CA2299926A1 - A process for the production of multiphase detergent tablets - Google Patents

Abstract

The invention relates to a process for the production of multiphase detergent tablets, in which a particulate premix is tabletted, one or more adhesion promoter(s) is/are optionally applied to the surfaces of the tablet, after which additional active substance is applied in solid, highly viscous or plastic form, optionally followed by an aftertreatment (post forming) of the active substances applied to the surface of the tablet. The detergent tablets obtained in this way are distinguished by excellent storage and transportation stability and are superior in their performance to conventional products in various fields of application

Description

08.12.1999 A Process for the Production of Multiphase Detergent Tablets This invention relates to a process for the production of multiphase tablets in which the individual phases may have different compositions.
The proposed process is particularly suitable for the production of detergent tablets such as, for example, bleach tablets, stain remover tablets, dishwasher tablets, laundry detergent tablets and water softening tablets.
Rotary presses for the production of tablets from various materials and for various applications are known from the prior art. In rotary presses, a die disk driven about a (generally vertical) axis comprises bores (dies) arranged in a circle with which pairs of punches synchronously revolving with the disk are associated. The punches are raised and lowered by control cams and pressure rollers so that the mixture introduced into the die is compressed and ejected. During the filling of the dies by a suitable filling tool (filling shoe), the base of the die is formed by the bottom punch, the die volume and hence the dosing of the mixture to be tabletted depending on the level of the bottom punch in the die bore. After introduction into the die, the premix is compressed to the required extent by lowering of the top punch by means of a pressure roller or by the movement of opposite punches towards one another, modern pressing stations comprising a preliminary and a principal pressure station. After compression, the top and bottom punches are raised so that the tablet emerges from the die at a certain point of the machine and can be removed from the die disk by suitable tools (strippers) and delivered to a discharge tube. During this phase, the top punch is generally raised faster and to a greater extent than the bottom punch.

With known rotary presses, it is possible to produce not only tablets of homogeneous composition, i.e. single-phase tablets, but also multilayer tablets through the incorporation of several filling shoes and pressure rollers or ejection rails. The first layer introduced is only lightly precompressed, if at all, the final compression taking place after the die has been filled with the premix for the last layer in order to improve the cohesion of the individual layers. Other geometric "phase divisions" such as, for example, jacketed tablets or ringlcore tablets (normally referred to in the pharmaceutical field as bull's-eye tablets) can also be produced in conventional rotary presses through the provision of a transfer and centering mechanism which places a precompressed core in the filled die before the mixture as a whole is compressed.
The shape of the die bores and the punch surfaces can be varied within wide limits. Thus, round, oval and angular tablets with a flat or curved surface or with bevelled edges can be produced.
The production of ring-shaped tablets in rotary presses is known from battery manufacture. The graphite/manganese rings subsequently filled with a carbon rod are produced by an annular bottom punch, a fixed central spike past which the bottom punch moves upwards and downwards projecting into the die from below. The bottom punch is provided in its lower part with two notches which slide past the mounting of the central spike.
Extensive literature is available on the production processes mentioned, particularly in the pharmaceutical field. Besides manuals on pharmaceutical technology, such as "Hagers Handbuch der pharmazeutischen Praxis'; Vol. 2, 5th Edition 199 9, Springer Verlag, Berlin, Heidelberg, New York, London, Paris, Tokyo, Hong Kong, Barcelona, Budapest, pages 938 et seq or K.H. Bauer, K.-H. Fromming, C.
Ftihrer "Pharmazeutische Technologie'; 4th Edition 7997, Gustav Fischer Verlag Stuttgart, Jena, Lubeck, Ulm, pages 299 et seq, there are numerous special works, for example the three-volume work of H.A. Liebermann, L.
Lachmann and J.B. Schwartz entitled Pharmaceutical Dosage Forms -Tablets'; M. Dekker Inc., New York, 1989.
There are also various patents on the production of multilayer or multiphase tablets. Thus, US patent 5,158,728 (Sanderson et al.) discloses a press for making specially shaped two-layer tablets. Three layer tablets which are used in battery production are described in EP-A-0 307 209 (Sharp). A rotary press for making two-layer tablets is also described in German utility model application G 92 08 040.5 U1. This press has an intermediate removal station with an adjustable ejector rail segment and a siding or switch by which the tablets can be delivered to a reject tube or to a test station.
Multiphase or multilayer tablets are also known in the field of detergents. In this case, considerable significance attaches to the separation of active ingredients. Thus, European patent applications EP
851 023, EP 851 024 and EP 851 025 (all Unilever) describe two-layer tablets made by conventional tabletting technology which, in the first layer, contain builders, enzymes, a buffer system and optionally bleaching agents while a wax, acidifying agents and optionally peracids andlor antiscaling polymers are accommodated in a second layer. Temperature-controlled release of the active substances in the second layer can be achieved through the choice of the melting point of the waxes used (35-50°C or 70°C).
Another process for producing two-phase or multiphase detergent tablets is described in hitherto unpublished German patent application DE
198 31 704.2 (Henkel KGaA). According to the teaching of this document, a particulate premix is compressed to form tablets which have a recess.
This recess is then filled with a melt suspension or emulsion of a coating material with a melting point above 30°C and one or more active substances) dispersed or suspended therein at temperatures above the melting point of the coating material, after which the tablets are cooled and optionally aftertreated.
This process enables tablets differing from the conventional layered structure to be produced. This optical differentiation on the one hand underscores the unmistakability of a product; on the other hand, aesthetic advantages are achieved because the recognition effect is greater with optical differentiation so that consumer acceptance increases.
Now, the problem addressed by the present invention was to develop other processes for the production of multiphase detergent tablets.
These processes on the one hand would be inexpensive to cant' out, even on an industrial scale, and would allow incompatible ingredients to be separated; on the other hand, the tablets produced by the proposed process would have a high level of optical independence which would increase consumer acceptance. Known tablet forms, such as multilayer tablets, ring core tablets, jacket tablets, recess tablets, bull's-eye tablets, etc., were not considered as a solution.
The present invention relates to a process for the production of multiphase detergent tablets which comprises the following steps:
a) tabletting a particulate premix, b) optionally applying one or more adhesion promoters to one or more surfaces of the tablet, c) applying additional active substance in solid, highly viscous or plastic form, d) optionally aftertreating (postforming) the active substances applied to the surtace of the tablet.
The process according to the invention is explained step-by-step in the following.
In step a), a particulate premix containing ingredients of detergents is conventionally compacted between two punches in a die to form a solid compactate. This process, which is referred to in short hereinafter as tabletting, comprises four phases, namely metering, compacting (elastic deformation), plastic deformation and ejection.
The premix is first introduced into the die, the filling level and hence the weight and shape of the tablet formed being determined by the position of the lower punch and the shape of the die. Uniform metering, even at high tablet throughputs, is preferably achieved by volumetric metering of the premix. As the tabletting process continues, the top punch comes into contact with the premix and continues descending towards the bottom punch. During this compaction phase, the particles of the premix are pressed closer together, the void volume in the filling between the punches continuously diminishing. The plastic deformation phase in which the particles coalesce and form the tablet begins from a certain position of the top punch (and hence from a certain pressure on the premix). Depending on the physical properties of the premix, its constituent particles are also partly crushed, the premix sintering at even higher pressures. As the tabletting rate increases, i.e. at high throughputs, the elastic deformation phase becomes increasingly shorter so that the tablets formed can have more or less large voids. In the final step of the tabletting process, the tablet is forced from the die by the bottom punch and carried away by following conveyors. At this stage, only the weight of the tablet is definitively established because the tablets can still change shape and size as a result of physical processes (re-elongation, crystallographic effects, cooling, etc.).
The tabletting process is carried out in commercially available tablet presses which, in principle, may be equipped with single or double punches. In the latter case, not only is the top punch used to build up pressure, the bottom punch also moves towards the top punch during the tabletting process while the top punch presses downwards. For small production volumes, it is preferred to use eccentric tablet presses in which the punches) islare fixed to an eccentric disc which, in turn, is mounted on a shaft rotating at a certain speed. The movement of these punches is comparable with the operation of a conventional four-stroke engine.
Tabletting can be carried out with a top punch and a bottom punch, although several punches can also be fixed to a single eccentric disc, in which case the number of die bores is correspondingly increased. The throughputs of eccentric presses vary according to type from a few hundred to at most 3,000 tablets per hour.
For larger throughputs, rotary tablet presses are generally used. In rotary tablet presses, a relatively large number of dies is arranged in a circle on a so-called die table. The number of dies varies - according to model - between 6 and 55, although even larger dies are commercially available. Top and bottom punches are associated with each die on the die table, the tabletting pressures again being actively built up not only by the top punch or bottom punch, but also by both punches. The die table and the punches move about a common vertical axis, the punches being brought into the filling, compaction, plastic deformation and ejection positions by means of curved guide rails. At those places where the punches have to be raised or lowered to a particularly significant extent (filling, compaction, ejection), these curved guide rails are supported by additional push-down members, pull-down rails and ejection paths. The die is filled from a rigidly arranged feed unit, the so-called filling shoe, which is connected to a storage container for the compound. The pressure applied to the premix can be individually adjusted through the tools for the top and bottom punches, pressure being built up by the rolling of the punch shank heads past adjustable pressure rollers.
To increase throughput, rotary presses can also be equipped with two filling shoes so that only half a circle has to be negotiated to produce a tablet. To produce two-layer or multiple-layer tablets, several filling shoes are arranged one behind the other without the lightly compacted first layer being ejected before further filling. Given suitable process control, shell and bull's-eye tablets - which have a structure resembling an onion skin -can also be produced in this way. In the case of bull's-eye tablets, the upper surface of the core or rather the core layers is not covered and thus remains visible. Rotary tablet presses can also be equipped with single or multiple punches so that, for example, an outer circle with 50 bores and an inner circle with 35 bores can be simultaneously used for tabletting.
Modern rotary tablet presses have throughputs of more than one million tablets per hour.
Tabletting machines suitable for step a) of the process according to the invention can be obtained, for example, from the following companies:
Apparatebau Holzwarth GbR, Asperg, Wilhelm Fette GmbH, Schwarzenbek, Hofer GmbH, Weil, KILIAN, Cologne, KOMAGE, Kell am See, KORSCH Pressen GmbH, Berlin, Mapag Maschinenbau AG, Bern (Switzerland) and Courtoy N.V., Halle (BE/LU). One example of a particularly suitable tabletting machine is the model HPF 630 hydraulic double-pressure press manufactured by LAEIS, D.
The tablets can be made in certain shapes and certain sizes.
Suitable shapes are virtually any easy-to-handle shapes, for example slabs, bars, cubes, squares and corresponding shapes with flat sides and, in particular, cylindrical forms of circular or oval cross-section. This last embodiment encompasses shapes from tablets to compact cylinders with a height-to-diameter ratio of more than 1.
The portioned pressings may be formed as separate individual elements which correspond to a predetermined dose of the detergent.
However, it is also possible to form pressings which combine several such units in a single pressing, smaller portioned units being easy to break off in particular through the provision of predetermined weak spots. For the use of laundry detergents in machines of the standard European type with horizontally arranged mechanics, it can be of advantage to produce the portioned pressings a~s cylindrical or square tablets, preferably with a diameter-to-height ratio of about 0.5:2 to 2:0.5. Commercially available hydraulic presses, eccentric presses and rotary presses are particularly suitable for the production of pressings such as these.
The three-dimensional form of another embodiment of the tablets according to the invention is adapted in its dimensions to the dispensing compartment of commercially available domestic washing machines, so that the tablets can be introduced directly, i.e. without a dosing aid, into the dispensing compartment where they dissolve on contact with water. If dishwasher tablets according to the invention are to be produced, a rectangular base where the height of the tablet is smaller than the smaller side of the rectangle is recommended. Rounded-off corners are preferred for this form of tablet.
Another preferred tablet which can be produced has a plate-like or slab-like structure with alternately thick long segments and thin short segments, so that individual segments can be broken off from this "bar" at the predetermined weak spots, which the short thin segments represent, and introduced into the machine. This "bar" principle can also be embodied in other geometric forms, for example vertical triangles which are only joined to one another at one of their longitudinal sides.
In another possible embodiment, however, the various components are not compressed to form a single tablet, instead the tablets obtained in steo a) comprise several layers, i.e. at least two layers. These various layers may have different dissolving rates. This can provide the tablets with favorable performance properties. If, for example, the tablets contain components which adversely affect one another, one component may be integrated in the more quickly dissolving layer while the other component may be incorporated in a more slowly dissolving layer so that the first component can already have reacted off by the time the second component dissolves. The various layers of the tablets can be arranged in the form of a stack, in which case the inner layers) dissolve at the edges of the tablet before the outer layers have completely dissolved. Alternatively, however, the inner layers) may also be completely surrounded by the layers lying further to the outside which prevents constituents of the inner layers) from dissolving prematurely.
After pressing, the detergent tablets have high stability. The fracture resistance of cylindrical tablets can be determined via the diametral fracture stress. This in turn can be determined in accordance with the following equation:

a-nDt.
The premix to be tabletted may contain any typical detergent ingredients, its composition varying according to the application envisaged for the subsequent tablet. Thus, laundry detergent tablets contain larger quantities of surfactants than dishwasher tablets whereas bleach tablets and water softening tablets are normally surfactant-free. The quantity and type builders, bleaching agents, etc. used may also vary according to the application envisaged. Irrespective of the intended application, most detergent tablets contain one or more substances from the group of builders. The builder present in the laundry and dishwasher detergent tablets produced in step a) of the process according to the invention may be selected from any of the builders typically present in detergents, i.e. in particular zeolites, silicates, carbonates, organic cobuilders and also the phosphates.
Suitable crystalline layered sodium silicates correspond to the general formula I NaMSiXO~+~~ yH20, where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x being 2, 3 or 4. Crystalline layered silicates such as these are described, for example, in European patent application EP-A-0 164 514. Preferred crystalline layered silicates corresponding to the above formula are those in which M is sodium and x assumes the value 2 or 3. Both a- and b-sodium disilicates NaZSi205 ~ yH20 are particularly preferred, ~i-sodium disilicate being obtainable, for example; by the process described in International patent application WO-A- 91108171.
Other useful builders are amorphous sodium silicates with a modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash cycle properties. The delay in dissolution in relation to conventional amorphous sodium silicates can have been obtained in various ways, for example by surface treatment, compounding, compacting or by overdrying.
In the context of the invention, the term "amorphous" is also understood to encompass "X-ray amorphous". In other words, the silicates do not produce any of the sharp X-ray reflexes typical of crystalline substances in X-ray diffraction experiments, but at best one or more maxima of the scattered X-radiation which have a width of several degrees of the diffraction angle. However, particularly good builder properties may even be achieved where the silicate particles produce crooked or even sharp diffraction maxima in electron diffraction experiments. This may be interpreted to mean that the products have microcrystalline regions between 10 and a few hundred nm in size, values of up to at most 50 nm and, more particularly, up to at most 20 nm being preferred. So-called X
ray amorphous silicates such as these, which also dissolve with delay in relation to conventional waterglasses, are described for example in German patent application DE-A-44 00 024. Compacted amorphous silicates, compounded amorphous silicates and overdried X-ray-amorphous silicates are particularly preferred.
The finely crystalline, synthetic zeolite containing bound water used in accordance with the invention is preferably zeolite A andlor zeolite P.
Zeolite MAP~ (Crosfield) is a particularly preferred P-type zeolite.
However, zeolite X and mixtures of A, X andlor P are also suitable.
According to the invention, it is prefer-ed to use, for example, a commercially obtainable co-crystallizate of zeolite X and zeolite A (ca. 80%
by weight zeolite X) which is marketed by CONDEA Augusta S.p.A. under the name of VEGOBOND AX~ and which may be described by the following formula:
nNa20 ~ (1-n)K20 ~ AI203 - (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and for "powdering" the entire mixture to be tabletted, both these options normally being used to incorporate the zeolite in the premix. Suitable zeolites have a mean particle size of less than 10 pm (volume distribution, as measured by the Coulter Counter Method) and contain preferably 18 to 22% by weight and more preferably 20 to 22% by weight of bound water.
The generally known phosphates may of course also be used as builders providing their use should not be avoided on ecological grounds.
The sodium salts of the orthophosphates, the pyrophosphates and, in particular, the tripolyphosphates are particularly suitable.
Organic cobuilders suitable for use in the deternPnt tahlatc according to the invention are, in particular, polycarboxylateslpolycarboxylic acids, polymeric polycarboxylates, aspartic acid, polyacetals, dextrins, other organic cobuilders (see below) and phosphonates. These classes of substances are described in the following.
Useful organic builders are, for example, the polycarboxylic acids usable, for example, in the form of their sodium salts, polycarboxylic acids in this context being understood to be carboxylic acids which bear morre than one acid function. Examples of such carboxylic acids are citric acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing their use is not ecologically unsafe, and mixtures thereof.
Preferred salts are the salts of the polycarboxylic acids, such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid, sugar acids and mixtures thereof.
The acids per se may also be used. Besides their builder effect, the acids also typically have the property of an acidifying component and, hence, also serve to establish a relatively low and mild pH value in detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof are particularly mentioned in this regard.
Other suitable builders are polymeric polycarboxylates such as, for example, the alkali metal salts of polyacrylic or polymethacrylic acid, for example those with a relative molecular weight of 500 to 70,000 g/mol.
The molecular weights mentioned in this specification for polymeric polycarboxylates are weight-average molecular weights Mw of the particular acid form which, basically, were determined by gel permeation chromatography (GPC) using a UV detector. The measurement was carried out against an external polyacrylic acid standard which provides realistic molecular weight values by virtue of its structural similarity to the polymers investigated. These values differ distinctly from the molecular weights measured against polystyrene sulfonic acids as standard. The molecular weights measured against polystyrene sulfonic acids are generally higher than the molecular weights mentioned in this specification.
Particularly suitable polymers are polyacrylates which preferably have a molecular weight of 2,000 to 20,000 glmol. By virtue of their superior solubility, preferred representatives of this group are the short-chain polyacrylates which have molecular weights of 2,000 to 10,000 g/mol and, more particularly, 3,000 to 5,000 g/mole.
Also suitable are copolymeric polycarboxylates, particularly those of acrylic acid with methacrylic acid and those of acrylic acid or methacrylic acid with malefic acid. Acrylic acidlmaleic acid copolymers containing 50 to 90% by weight of acrylic acid and 50 to 10% by weight of malefic acid have proved to be particularly suitable. Their relative molecular weights, based on the free acids, are generally in the range from 2,000 to 70,000 glmol, preferably in the range from 20,000 to 50,000 g/mol and more preferably in the range from 30,000 to 40,000 g/mol.
The (co)polymeric polycarboxylates may be used either in powder form or in the form of an aqueous solution. The content of (co)polymeric polycarboxylates in the detergent is preferably from 0.5 to 20% by weight and more preferably from 3 to 10% by weight.
In order to improve solubility in water, the polymers may also contain allyl sulfonic acids, such as allyloxybenzene sulfonic acid and methallyl sulfonic acid, as monomer.
Other particularly preferred polymers are biodegradable polymers of more than two different monomer units, for example those which contain salts of acrylic acid and malefic acid and vinyl alcohol or vinyl alcohol derivatives as monomers or those which contain salts of acrylic acid and 2-alkylallyl sulfonic acid and sugar derivatives as monomers.
Other prefer-ed copolymers are those which are described in German patent applications DE-A-43 03 320 and DE-A-44 17 734 and which preferably contain acrolein and acrylic acidlacrylic acid salts or acrolein and vinyl acetate as monomers.
Other preferred builders are polymeric aminodicarboxylic acids, salts or precursors thereof. Particular preference is attributed to polyaspartic acids or salts and derivatives thereof which, according to German patent application DE-A-195 40 086, are also said to have a bleach-stabilizing effect in addition to their co-builder properties.
Other suitable builders are polyacetals which may be obtained by reaction of dialdehydes with polyol carboxylic acids containing 5 to 7 carbon atoms and at least three hydroxyl groups. Preferred polyacetals are obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthal-aldehyde and mixtures thereof and from polyol carboxylic acids, such as gluconic acid andlor glucoheptonic acid.

Other suitable organic builders are dextrins, for example oligomers or polymers of carbohydrates which may be obtained by partial hydrolysis of starches. The hydrolysis may be carried out by standard methods, for example acid- or enzyme-catalyzed methods. The end products are preferably hydrolysis products with average molecular weights of 400 to 500,000 g/mol. A polysaccharide with a dextrose equivalent (DE) of 0.5 to 40 and, more particularly, 2 to 30 is preferred, the DE being an accepted measure of the reducing effect of a polysaccharide by comparison with dextrose which has a DE of 100. Both maltodextrins with a DE of 3 to 20 and dry glucose sirups with a DE of 20 to 37 and also so-called yellow dextrins and white dextrins with relatively high molecular weights of 2,000 to 30,000 g/mol may be used.
The oxidized derivatives of such dextrins are their reaction products with oxidizing agents which are capable of oxidizing at least one alcohol function of the saccharide ring to the carboxylic acid function. Dextrins thus oxidized and processes for their production are known, for example, from European patent applications EP-A-0 232 202, EP-A-0 427 349, EP-A-0 472 042 and EP-A-0 542 496 and from International patent applications WO 92118542, WO 93!08251, WO 93/16110, WO 94128030, WO 95!07303, WO 95112619 and WO 95120608. An oxidized oligosaccharide corresponding to German patent application DE-A-196 00 018 is also suitable. A product oxidized at Cs of the saccharide ring can be particularly advantageous.
Other suitable co-builders are oxydisuccinates and other derivatives of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine N,N'-disuccinate (EDDS) is preferably used in the form of its sodium or magnesium salts. Glycerol disuccinates and glycerol trisuccinates are also preferred in this connection. The quantities used in zeolite-containing andlor silicate-containing formulations are from 3 to 15% by weight.
Other useful organic co-builders are, for example, acetylated hydroxycarboxylic acids and salts thereof which may optionally be present in lactone form and which contain at least 4 carbon atoms, at least one hydroxy group and at most two acid groups. Co-builders such as these are described, for example, in International patent application WO-A-95120029.
Another class of substances with co-builder properties are the phosphonates, more particularly hydroxyalkane and aminoalkane phos-phonates. Among the hydroxyalkane phosphonates, 1-hydroxyethane-1,1-diphosphonate (HEDP) is particularly important as a co-builder. It is preferably used in the form of a sodium salt, the disodium salt showing a neutral reaction and the tetrasodium salt an alkaline ration (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene phosphonate (EDTMP), diethylenetriamine pentamethylene phosphonate (DTPMP) and higher homologs thereof. They are preferably used in the form of the neutrally reacting sodium salts, for example as the hexasodium salt of EDTMP and as the hepta- and octasodium salt of DTPMP. Within the class of phosphonates, HEDP is preferably used as builder. The aminoalkane phosphonates also show a pronounced heavy metal binding capacity. Accordingly, it can be of advantage, particularly where the detergents also contain bleaching agents, to use aminoalkane phosphonates, more especially DTPMP, or mixtures of the phosphonates mentioned.
In addition, any compounds capable of forming complexes with alkaline earth metal ions may be used as co-builders.
In dishwasher tablets produced in accordance with the invention, water-soluble builders are preferably used because, generally, they tend less to form insoluble residues on tableware and hard surfaces.
Conventional builders which may be present in dishwasher detergents according to the invention in quantities of 10 to 90% by weight are the low molecular weight polycarboxylic acids and salts thereof, the homopolymeric and copolymeric polycarboxylic acids and salts thereof, the carbonates, phosphates and silicates. Trisodium citrate and/or pentasodium tripolyphosphate andlor sodium carbonate andlor sodium bicarbonate andlor gluconates and/or silicate-based builders from the class of disilicates and/or metasilicates are preferably used for the production of dishwasher tablets. A builder system containing a mixture of tripoly-phosphate and sodium carbonate is particularly preferred. A builder system containing a mixture of tripolyphosphate and sodium carbonate and sodium disilicate is also particularly preferred.
According to the invention, preferred process variants are characterized in that the particulate premix tabletted in step a) contains builders in quantities of 20 to 80% by weight, preferably in quantities of 25 to 75% by weight and more preferably in quantities of 30 to 70% by weight, based on the premix.
In addition to the builders described above, the premix may also contain the detersive substances already mentioned which are particularly important ingredients for detergent tablets. Depending on the tablet to be produced, different answers are possible to the questions of whether to use surfactants and, if so, which surfactants to use. Laundry detergent tablets may normally contain various surfactants from the groups of anionic, nonionic, cationic and amphoteric surfactants whereas dishwasher tablets preferably contain only low-foaming nonionic surfactants and water softening tablets or bleach tablets are free from surfactants. When it comes to incorporating the surfactants in the particular premix to be compressed, there are no limits to the freedom of formulation available to the expert.
Suitable anionic surfactants are, for example, those of the sulfonate and sulfate type. Suitable surfactants of the sulfonate type are preferably Cs_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the disulfonates obtained, for example, from C,2_~8 monoolefins with an internal or terminal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Other suitable surfactants of the sulfonate type are the alkane sulfonates obtained from C~2_~8 alkanes, for example by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated methyl esters of hydrogenated coconut, palm kernel or tallow fatty acids, are also suitable.
Other. suitable anionic surfactants are sulfonated fatty acid glycerol esters. Fatty acid glycerol esters in the context of the present invention are the monoesters, diesters and triesters and mixtures thereof which are obtained where production is can-ied out by esterification of a monoglycerol with 1 to 3 moles of fatty acid or in the transesterification of triglycerides with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid glycerol esters are the sulfonation products of saturated fatty acids containing 6 to 22 carbon atoms, for example caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in particular, the sodium salts of the sulfuric acid semiesters of C~2_~8 fatty alcohols, for example coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl or stearyl alcohol, or C~o_2o oxoalcohols and the corresponding semiesters of secondary alcohols with the same chain length. Other preferred alk(en)yl sulfates are those with the chain length mentioned which contain a synthetic, linear alkyl chain based on a petrochemical and which are similar in their degradation behavior to the corresponding compounds based on oleochemical raw materials. C~Z_~s alkyl sulfates, C~2_~5 alkyl sulfates and C,ø~5 alkyl sulfates are preferred from the point of view of washing technology. Other suitable anionic surfactants are 2,3-alkyl sulfates which may be produced, for example, in accordance with US
3,234,258 or US 5,075,041 and which are commerially obtainable as products of the Shell Oil Company under the name of DANA.

The sulfuric acid monoesters of linear or branched C~_2, alcohols ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched Cs_> > alcohols containing on average 3.5 moles of ethylene oxide (EO) or C,2_,8 fatty alcohols containing 1 to 4 EO, are also suitable. In view of their high foaming capacity, they are only used in relatively small quantities, for example in quantities of 1 to 5% by weight, in dishwashing detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or as sulfosuccinic acid esters and which represent monoesters and/or diesters of sulfosuccinic acid with alcohols, preferably fatty alcohols and, more particularly, ethoxylated fatty alcohols. Preferred sulfosuccinates contain Cs_~8 fatty alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates contain a fatty alcohol residue derived from ethoxylated fatty alcohols which, considered in isolation, represent nonionic surfactants (for a description, see below). Of these sulfosuccinates, those of which the fatty alcohol residues are derived from narrow-range ethoxylated fatty alcohols are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to 18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable soaps are saturated fatty acid soaps, such as the salts of lauric acid, myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and behenic acid, and soap mixtures derived in particular from natural fatty acids, for example coconut oil, palm kernel oil or tallow fatty acids.
The anionic surfactants, including the soaps, may be present in the form of their sodium, potassium or ammonium salts and as soluble salts of organic bases, such as mono-, di- or triethanolamine. The anionic surfactants are preferably present in the form of their sodium or potassium salts and, more preferably, in the form of their sodium salts.
If laundry detergent tablets are produced by the process according to the invention, they preferably contain anionic surfactants) in quantities H 3841-I PCT 1 g of 5 to 50% by weight, preferably in quantities of 7.5 to 40% by weight and more preferably in quantities of 10 to 20% by weight, based on the weight of the tablet.
So far as the choice of the anionic surfactants used in the detergent tablets according to the invention is concerned, there are no basic requirements to restrict freedom of formulation. However, preferred detergent tablets do have a soap content of more than 0.2% by weight, based on the total weight of the tablet. Preferred anionic surfactants are the alkyl benzenesulfonates and fatty alcohol sulfates, preferred detergent tablets containing 2 to 20% by weight, preferably 2.5 to 15% by weight and more preferably 5 to 10% by weight of fatty alcohol sulfate(s), based on the weight of the tablet.
Preferred nonionic surfactants are alkoxylated, advantageously ethoxylated, more especially primary alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol radical may be linear or, preferably, methyl-branched in the 2-position or may contain linear and methyl-branched radicals in the form of the mixtures typically present in oxoalcohol radicals. However, alcohol ethoxylates containing linear radicals of alcohols of native origin with 12 to 18 carbon atoms, for example coconut oil, palm oil, tallow or oleyl alcohol, and on average 2 to 8 EO per mole of alcohol are particularly preferred. Preferred ethoxylated alcohols include, for example, C,2_~4 alcohols containing 3 EO or 4 EO, Cs_» alcohol containing 7 EO, C,3_,s alcohols containing 3 EO, 5 EO, 7 EO or 8 EO, C~2_~8 alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such as mixtures of C~2_~4 alcohol containing 3 EO and C~2_~8 alcohol containing 5 E0. The degrees of ethoxylation mentioned represent statistical mean values which, for a special product, can be a whole number or a broken number. Preferred alcohol ethoxylates have a narrow homolog distribution (narrow range ethoxylates, NRE). In addition to these nonionic surfactants, fatty alcohols containing more than 12 EO may also be used, examples including tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
Another class of preferred nonionic surfactants which may be used either as sole nonionic surtactant or in combination with other nonionic surfactants are alkoxylated, preferably ethoxylated or ethoxylated and propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon atoms in the alkyl chain, more especially the fatty acid methyl esters which are described, for example, in Japanese patent application JP 58/217598 or which are preferably produced by the process described in International patent application WO-A-90113533.
Another class of nonionic surtactants which may advantageously be used are the alkyl polyglycosides (APGs). Suitable alkyl polyglycosides correspond to the general formula RO(G)Z where R is a linear or branched, more particularly 2-methyl-branched, saturated or unsaturated aliphatic radical containing 8 to 22 and preferably 12 to 18 carbon atoms and G
stands for a glycose unit containing 5 or 6 carbon atoms, preferably glucose. The degree of glycosidation is between 1.0 and 4.0, preferably between 1.0 and 2.0 and more preferably between 1.1 and 1.4.
Linear alkyl polyglucosides, i.e. alkyl polyglycosides in which the polyglycosyl moiety is a glucose unit and the alkyl moiety is an n-alkyl group, are preferably used.
The detergent shaped bodies according to the invention may advantageously contain alkyl polyglycosides, APG contents in the tablets of more than 0.2% by weight, based on the tablet as a whole, being preferred.
Particularly preferred detergent tablets contain APGs in quantities of 0.2 to 10% by weight, preferably in quantities of 0.2 to 5% by weight and more preferably in quantities of 0.5 to 3% by weight.
Nonionic surfactants of the amine oxide type, for example N
cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethyl amine oxide, and the fatty acid alkanolamide type are also suitable. The quantity in which these nonionic surfactants are used is preferably no more than the quantity in which the ethoxylated fatty alcohols are used and, more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides corresponding to formula (I):
R' R-C O-N-[Z] ( I ) in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms, R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon atoms and (Z] is a linear or branched polyhydroxyalkyl group containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid amides are known substances which may normally be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds corresponding to formula (II):
R'-O-R2 R-C O-N-[Z] ( I I ) in which R is a linear or branched alkyl or alkenyl group containing 7 to 12 carbon atoms, R' is a linear, branched or cyclic alkyl group or an aryl group containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms, C,~, alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxy-alkyl group, of which the alkyl chain is substituted by at least two hydroxyl groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives of that group.

[Z] is preferably obtained by reductive amination of a reduced sugar, for example glucose, fructose, maltose, lactose, galactose, mannose or xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be converted into the required polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the presence of an alkoxide as catalyst, for example in accordance with the teaching of International patent application WO-A-95107331.
In the production of dishwasher tablets, the surtactants used may again be selected in principle from any surfactants. However, the nonionic surfactants described above are preferably used for this particular application, low-foaming nonionic surfactants being particularly suitable.
Alkoxylated alcohols, above all ethoxylated andlor propoxylated alcohols, are particularly preferred. The expert generally understands alkoxylated alcohols to be the reaction products of alkylene oxide, preferably ethylene oxide, with alcohols, preferably - for the purposes of the present invention -relatively long-chain alcohols (C~o to C~e, preferably C~2 to C~6, such as for example C~~, C~2, C~3, C~4, CAS, Cps, C» and C~8 alcohols). In general, a complex mixture of addition products with different degrees of ethoxylation is formed from n moles of ethylene oxide and 1 mole of alcohol, depending on the reaction conditions. Another embodiment consists in the use of mixtures of alkylene oxide, preferably a mixture of ethylene oxide and propylene oxide. If desired, "end-capped" alcohol ethoxylates, which may also be used in accordance with the invention, may also be obtained by etherification with short-chain alkyl groups, such as preferably the butyl group, in a concluding step. Highly ethoxylated fatty alcohols or mixtures thereof with end-capped fatty alcohol ethoxylates are most particularly preferred for the purposes of the invention.
If the process according to the invention is used for the production of dishwasher tablets, the particulate premix tabletted in step a) preferably contains surfactants, preferably nonionic surfactant(s), in quantities of 0.5 to 10% by weight, preferably in quantities of 0.75 to 7.5% by weight and more preferably in quantities of 1.0 to 5% by weight, based on the premix.
Irrespective of the intended application of the tablets to be produced, it can be of advantage if the premix to be tabletted in step a) of the process according to the invention has certain physical properties. In this connection, particularly prefer-ed processes according to the invention are characterized in that the particulate premix tabletted in step a) has a bulk density above 600 gll, preferably above 700 gll and more preferably above 800 gll.
The particle size distribution of the premix can also influence the properties of the tablets produced in step a). Preferred processes according to the invention are characterized in that the particulate premix tabletted in step a) has a particle size distribution where less than 10% by weight, preferably less than 7.5% by weight and more preferably less than 5% by weight of the particles are larger than 1600 Nm or smaller than 200 Nm. The particle size distribution of the premix tabletted in step a) is preferably even narrower so that particularly preferred processes are characterized in that the particulate premix tabletted in step a) has a particle size distribution where more than 30% by weight, preferably more than 40% by weight and more preferably more than 50% by weight of the particles have a particle size of 600 to 1,000 Nm.
As described at the beginning, not only single-phase tablets but also multiphase or multilayer tablets produced in known manner by compressing several different particulate premixes onto one another can be produced in step a). Particular preference is attributed to the production of two-layer tablets in step a) by compressing two different particulate premixes, one of which contains one or more bleaching agents and the other one or more enzymes, onto one another. It is of course possible in this way to separate not only bleaching agent and oxidation-sensitive substances (enzymes, dyes and perfumes), but also bleaching agent and bleach activator by compressing two different particulate premixes, one of which contains one or more bleaching agents and the other one or more bleach activators, onto one another.
The ingredients mentioned and other ingredients of detergents such as, for example, disintegration aids, silver protectors, optical brighteners, dye transfer inhibitors, corrosion inhibitors, pH regulators, surfactants, enzymes, polymers, fluorescers, foam inhibitors, redeposition inhibitors, discoloration inhibitors and mixtures thereof may be present in the premixes which are tabletted in known manner in step a). These substances are described in the following.
Among the compounds yielding H202 in water which serve as bleaching agents, sodium perborate tetrahydrate and sodium perborate monohydrate are particularly important. Other useful bleaching agents are, for example, sodium percarbonate, peroxypyrophosphates, citrate perhy-drates and H202-yielding peracidic salts or peracids, such as perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. Where bleaching agents are used, it is again possible to leave out surfactants andlor builders so that pure bleach tablets can be produced. If such bleach tablets are to be used for washing laundry, sodium carbonate is preferably used irrespective of what other ingredients the tablets contain. If detergent or bleach tablets for dishwashing machines are being produced, bleaching agents from the group of organic bleaches may also be used. Typical organic bleaching agents are diacyl peroxides, such as dibenzoyl peroxide for example.
Other typical organic bleaching agents are the peroxy acids, of which alkyl peroxy acids and aryl peroxy acids are particularly mentioned as examples.
Preferred representatives are (a) peroxybenzoic acid and ring-substituted derivatives thereof, such as alkyl peroxybenzoic acids, but also peroxy-a-naphthoic acid and magnesium monoperphthalate, (b) aliphatic or substituted aliphatic peroxy acids, such as peroxylauric acid, peroxystearic acid, g-phthalimidoperoxycaproic acid [phthaloiminoperoxyhexanoic acid (PAP)], o-carboxybenzamidoperoxycaproic acid, N-nonenylamidoperadipic acid and N-nonenylamidopersuccinates and (c) aliphatic and araliphatic peroxydicarboxylic acids, such as 1,12-diperoxycarboxylic acid, 1,9-diperoxyazelaic acid, diperoxysebacic acid, diperoxybrassylic acid, diperoxyphthalic acids, 2-decyldiperoxybutane-1,4-dioic acid, N,N-terephthaloyl-di(6-aminopercaproic acid).
Other suitable bleaching agents in dishwasher tablets are chlorine and bromine-releasing substances. Suitable chlorine- or bromine-releasing materials are, for example, heterocyclic N-bromamides and N-chloramides, for example trichloroisocyanuric acid, tribromoisocyanuric acid, dibromo-isocyanuric acid andlor dichloroisocyanuric acid (DICA) and/or salts thereof with cations, such as potassium and sodium. Hydantoin compounds, such as 1,3-dichloro-5,5-dimethyl hydantoin, are also suitable.
In order to obtain an improved bleaching effect where washing is carried out at temperatures of 60°C or lower, bleach activators may be incorporated in the premix to be tabletted. The bleach activators may be compounds which form aliphatic peroxocarboxylic acids containing preferably 1 to 10 carbon atoms and more preferably 2 to 4 carbon atoms andlor optionally substituted perbenzoic acid under perhydrolysis conditions. Substances bearing O- and/or N-acyl groups with the number of carbon atoms mentioned and/or optionally substituted benzoyl groups are suitable. Preferred bleach activators are polyacylated alkylene-diamines, more particularly tetraacetyl ethylenediamine (TAED), acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated glycolurils, more particularly tetraacetyl glycoluril (TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides, more particularly phthalic anhydride, acylated polyhydric alcohols, more H 3841-I PCT 2g particularly triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-dihydrofuran.
In addition to or instead of the conventional bleach activators mentioned above, so-called bleach catalysts may also be incorporated in the shaped bodies. Bleach catalysts are bleach-boosting transition metal salts or transition metal complexes such as, for example, manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper complexes with nitrogen-containing tripod ligands and cobalt-, iron-, copper- and ruthenium-ammine complexes may also be used as bleach catalysts.
Suitable enzymes in premixes for dishwasher tablets are, in particular, those from the classes of hydrolases, such as proteases, esterases, lipases or lipolytic enzymes, amylases, cellulases or other glycosyl hydrolases and mixtures thereof. All these hydrolases contribute to the removal of stains, such as protein-containing, fat-containing or starch-containing stains. Oxidoreductases may also be used for bleaching.
Enzymes obtained from bacterial strains or fungi, such as Bacillus subtilis, Bacillus licheniformis, Streptomyces griseus, Coprinus cinereus and Humicola insolens and from genetically modified variants are particularly suitable. Proteases of the subtilisin type are preferably used, proteases obtained from Bacillus lentus being particularly preferred. Of particular interest in this regard are enzyme mixtures, for example of protease and amylase or protease and lipase or lipolytic enzymes or of protease, amylase and lipase or lipolytic enzymes or protease, lipase or lipolytic enzymes, but especially protease- andlor lipase-containing mixtures or mixtures with lipolytic enzymes. Examples of such lipolytic enzymes are the known cutinases. Peroxidases or oxidases have also been successfully used in some cases. Suitable amylases include in particular a-amylases, isoamylases, pullanases and pectinases.

The enzymes may be adsorbed to supports and/or encapsulated in shell-forming substances to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme granules in the tablets according to the invention may be, for example, from about 0.1 to 5% by weight and is preferably from 0.5 to about 4.5% by weight.
In premixes for laundry detergent tablets, cellulases may also be used in addition to the enzymes mentioned above. Cellulases and other glycosyl hydrolases can contribute towards color retention and towards increasing fabric softness by removing pilling and microfibrils. Preferred cellulases are cellobiohydrolases, endoglucanases and ~i-glucosidases, which are also known as cellobiases, and mixtures thereof. Since the various cellulase types differ in their CMCase and avicelase activities, the desired activities can be established by mixing the cellulases in the appropriate ratios.
If dishwasher tablets according to the invention are to be produced, they may contain corrosion inhibitors to protect the tableware or the machine itself, silver protectors being particularly important for dishwashing machines. Known corrosion inhibitors may be used. Above all, silver protectors selected from the group of triazoles, benzotriazoles, bisbenzotriazoles, aminotriazoles, alkylaminotriazoles and the transition metal salts or complexes may generally be used. Benzotriazole andlor alkylaminotriazole is/are particularly preferred. In addition, dishwashing formulations often contain corrosion inhibitors containing active chlorine which are capable of distinctly reducing the corrosion of silver surfaces.
Chlorine-free dishwashing detergents contain in particular oxygen- and nitrogen-containing organic redox-active compounds, such as dihydric and trihydric phenols, for example hydroquinone, pyrocatechol, hydroxy-hydroquinone, gallic acid, phloroglucinol, pyrogallol and derivatives of these compounds. Salt-like and complex-like inorganic compounds, such as salts of the metals Mn, Ti, Zr, Hf, V, Co and Ce are also frequently used.
Of these, the transition metal salts selected from the group of manganese andlor cobalt salts and/or complexes are preferred, cobalt(ammine) complexes, cobalt(acetate) complexes, cobalt(carbonyl) complexes, chlorides of cobalt or manganese and manganese sulfate being particularly preferred. Zinc compounds may also be used to prevent corrosion of tableware.
In addition, premixes for laundry detergent tablets produced in accordance with the invention may also contain components with a positive effect on the removability of oil and fats from textiles by washing (so-called soil repellents). This effect becomes particularly clear when a textile which has already been repeatedly washed with a detergent according to the invention containing this oil- and fat-dissolving component is soiled.
Preferred oil- and fat-dissolving components include, for example, nonionic cellulose ethers, such as methyl cellulose and methyl hydroxypropyl cellulose containing 15 to 30% by weight of methoxyl groups and 1 to 15%
by weight of hydroxypropoxyl groups, based on the nonionic cellulose ether, and the polymers of phthalic acid andlor terephthalic acid known from the prior art or derivatives thereof, more particularly polymers of ethylene terephthalates and/or polyethylene glycol terephthalates or anionically and/or nonionically modified derivatives thereof. Of these, the sulfonated derivatives of phthalic acid and terephthalic acid polymers are particularly preferred.
If laundry detergent tablets are to be produced, the premix to be tabletted may contain derivatives of diaminostilbenedisulfonic acid or alkali metal salts thereof as optical brighteners. Suitable optical brighteners are, for example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6 amino)-stilbene-2,2'-disulfonic acid or compounds of similar composition which contain a diethanolamino group, a methylamino group, an anilino group or a 2-methoxyethylamino group instead of the morpholino group.

H 3841-f PCT
9righteners of the substituted Biphenyl styryl h~Pe, ~ ample alkali metal salts of 4,4'-bas-(2-sulfostytyll-dlPhsnYl. 4,4'-bas-(4~oro-3~utfostyrylr Biphenyl or 4-(4-chlorostyryllf-4'-(2-sulfostyrYl)-GPh~YI, meY also be present. AAoctures of the brighteners mentioned above may also be used.
Perfumes may be added to the premix in the process aooor~ding to the invention to improve the aesdl~ impression created by the products and to provide the consumer not only with the required washing performance but also with a visually and sensotially "typical and unmistakable" product_ Suitable peTfutne oils or fragrances include individual perfume compounds, for example synthetic products ail the ester, ether, atdehyde, ketone, alcohol and hydrocarbon type. Perfume compounds of the ester type are, for example, benzyt acetate, phenoxyethyt isobutyrate, p-tert.butyt cydottexYl ate, linalyt acetate, dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzyt formats, ethyl methyl phenyl glydnate, allyl cydohexyi propionate, styrallyl propionate and benzyl salicyiate. The include, for example.
benzyl ethyl ether; the aldehydes include, for example, the I'weat alkanals containing B to 18 carbon atoms, dual,- atconellal, dtronellyi-oxyacetaldehyde, .cyclamen aldehyde, hydroxydtroneliel, filial and bourgeonai; the ketoses include, for example, the ionones, a -isomethyl ionone and methyl vedryl acetone; the alc#Ws include anetttol, citronellol, eugenol, geraniol, linalool, phenyl ethyl alcohol and terpineol and the hydrocarbons include, above all, the terperies, suds as limonene and pinene. However, mixtures of various perfumes which together produce an attractive perfume note are preferably used. Pertume oils such as these may also contain natural pefume mss obtainable from vegetable sources, for example pine, altos, jasmine, patd~ouli, rose or ylang ytang oil. Also suitadle are dory oil, camomile oil, dove oil, melissa oil, mint oil, cinnamon leaf oil, lime blossom oil, juniper berry oil. vetiver oil, olibanum oil, gaibanum oil and labdanum oil and orange blossom oil, neroli oil, orange peel oil and sandalwood oil.
The perfumes may be directly incorporated in the premix, although it can also be of advantage to apply the fragrances to supports which strengthen the adherence of the perfume to the washing and which provide the textiles with a long-lasting fragrance through a slower release of the perfume. Suitable support materials are, for example, cyclodextrins, the cyclodextrin/perfume complexes optionally being coated with other auxiliaries.
In order to facilitate the disintegration of heavily compacted tablets, disintegration aids, so-called tablet disintegrators, may be incorporated in them to shorten their disintegration times. According to Rompp (9th Edition, Vol. 6, page 4440) and Voigt "Lehrbuch der pharmazeutischen Technologie" (6th Edition, 1987, pages 182-184), tablet disintegrators or disintegration accelerators are auxiliaries which promote the rapid disintegration of tablets in water or gastric juices and the release of the pharmaceuticals in an absorbable form.
These substances, which are also known as "disintegrators" by virtue of their effect, are capable of undergoing an increase in volume on contact with water so that, on the one hand, their own volume is increased (swelling) and, on the other hand, a pressure can be generated through the release of gases which causes the tablet to disintegrate into relatively small particles. Well-known disintegrators are, for example, carbonate/citric acid systems, although other organic acids may also be used. Swelling disintegration aids are, for example, synthetic polymers, such as polyvinyl pyrrolidone (PVP), or natural polymers and modified natural substances, such as cellulose and starch and derivatives thereof, alginates or casein derivatives.
Preferred detergent tablets contain 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight of one or more disintegration aids, based on the weight of the tablet.

According to the invention, preferred disintegrators are cellulose-based disintegrators, so that preferred detergent tablets contain a cellulose-based disintegrator in quantities of 0.5 to 10% by weight, preferably 3 to 7% by weight and more preferably 4 to 6% by weight. Pure cellulose has the formal empirical composition (CsH~o05)~ and, formally, is a ~i-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules of glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units and, accordingly, have average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose by polymer-analog reactions may also be used as cellulose-based disintegrators. These chemically modified celluloses include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms have been substituted. However, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as cellulose derivatives.
The group of cellulose derivatives includes, for example, alkali metal celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and aminocelluloses. The cellulose derivatives mentioned are preferably not used on their own, but rather in the form of a mixture with cellulose as cellulose-based disintegrators. The content of cellulose derivatives in mixtures such as these is preferably below 50% by weight and more preferably below 20% by weight, based on the cellulose-based disintegrator. In one particularly preferred embodiment, pure cellulose free from cellulose derivatives is used as the cellulose-based disintegrator.
The cellulose used as disintegration aid is preferably not used in fine-particle form, but is converted into a coarser form, for example by granulation or compacting, before it is added to and mixed with the premixes to be tabletted. Detergent tablets which contain granular or optionally co-granulated disintegrators are described in German patent applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel) and in International patent application WO 98/40463 (Henkel). Further particulars of the production of granulated, compacted or co-granulated cellulose disintegrators can also be found in these patent applications. The particle sizes of such disintegration aids is mostly above 200 Nm, at least 90% by weight of the particles being between 300 and 1600 Nm in size and, more particularly, between 400 and 1200 Nm in size. According to the invention, the above-described relatively coarse-particle cellulose-based disintegrators described in detail in the cited patent applications are preferably used as disintegration aids and are commercially obtainable, for example under the name of Arbocel~ TF-30-HG from Rettenmaier.
Microcrystalline cellulose may be used as another cellulose-based disintegration aid or as part of such a component. This microcrystalline cellulose is obtained by partial hydrolysis of celluloses under conditions which only attack and completely dissolve the amorphous regions (ca. 30%
of the total cellulose mass) of the celluloses, but leave the crystalline regions (ca. 70%) undamaged. Subsequent de-aggregation of the microfine celluloses formed by hydrolysis provides the microcrystalline celluloses which have primary particle sizes of ca. 5 Nm and which can be compacted, for example, to granules with a mean particle size of 200 Nm.
In step b) of the process according to the invention, adhesion promoters are optionally applied to one or more surfaces of the tablets.
Step b) is necessary above all when the active substances to be applied in the following step are not sufficiently adhesive on their own to remain on the tablet and to withstand the mechanical stresses involved in packaging, transportation and handling without abrasion. Accordingly, where the active substances are not sufficiently adhesive, the function of step b) of the process is to "stick on" the substances in question. If the active substances selected in step c) are not sufficiently adhesive on their own, it is possible through step b) of the process to determine those surfaces of the tablet to which active substance is intended to adhere.

Suitable adhesion promoters are substances which provide the surfaces of the tablet to which they are applied with sufficient adhesiveness ("tackiness") for the substances applied in the following step of the process to adhere permanently to those surfaces. In principle, the substances mentioned in the relevant literature on adhesives and, in particular, in the textbooks on this subject are suitable as adhesion promoters. According to the present invention, particular significance attaches to the application of melts which have an adhesion-promoting effect at elevated temperature, but are solid, i.e. no longer tacky, after cooling.
Accordingly, preferred processes according to the invention are characterized in that melts of one or more substances with a melting range of 40°C to 75°C are applied as adhesion promoters to one or more surfaces of the tablet in step b).
The adhesion promoters optionally applied in step b) of the process are expected to satisfy various requirements on the one hand in relation to their melting of solidification behavior and, on the other hand, in regard to the material properties of the coating in the solidified state at ambient temperature. Since the layer of adhesion promoter applied to the tablet is intended permanently to hold the active substances "stuck on" during transportation or storage, it must be highly resistant to the impacts encountered, for example, during packaging or transportation. Accordingly, the adhesion promoters should either have at least partly elastic or at least plastic properties in order to be able to react to impact through elastic or plastic deformation without breaking up. The adhesion promoters should have a melting range (solidification range) in a temperature range in which the active substances to be applied are not exposed to excessive heat. On the other hand, however, the melting range must be high enough to afford the active substances applied effective adhesion at at least slightly elevated temperature. According to the invention, the adhesion promoters preferably have a melting point above 30°C. The width of the melting range of the adhesion promoters also impacts directly on the operation of the process. The tablet coated with adhesion promoter has to be brought into contact with the active substances to be applied in the following process step without any loss of adhesiveness in the meantime. After the active substances have been applied, adhesiveness should be reduced as quickly as possible in order to avoid unnecessary losses of time and caking or blockages in following process steps or during handling and packaging.
In cases where melts are used, the reduction in adhesiveness can be supported by cooling (for example by blowing on cold air).
It has been found to be of advantage if the adhesion promoters do not have a sharply defined melting point, as would normally be the case with pure crystalline substances, but rather a melting range possibly covering several degrees Celsius.
The adhesion promoters preferably have a melting range of about 45°C to about 75°C. This means in the present case that the melting range lies within the temperature range mentioned and does not denote the width of the melting range. The width of the melting range is preferably at least 1 °C and more preferably about 2 to about 3°C.
The properties mentioned above are generally exhibited by so-called waxes. "Waxes" in the context of the present invention are understood to be any of a number of natural or synthetic substances Which generally melt above 40°C without decomposing and, even just above their melting point, are of relatively low viscosity and non-stringing. Their consistency and solubility are dependent to a large extent on temperature.
Waxes are divided into three groups according to their origin, namely: natural waxes, chemically modified waxes and synthetic waxes.
The natural waxes include, for example, vegetable waxes, such as candelilla wax, carnauba wax, Japan wax, espartograss wax, cork wax, guaruma wax, rice oil wax, sugar cane wax, ouricury wax or montan wax, animal waxes, such as bees wax, shellac wax, spermaceti, lanolin (wool wax) or uropygial fat, mineral waxes, such as ceresine or ozocerite (earth wax), or petrochemical waxes, such as petrolatum, paraffin waxes or microwaxes.
The chemically modified waxes include, for example, hard waxes, such as montan ester waxes, sassol waxes or hydrogenated jojoba waxes.
Synthetic waxes are generally understood to be polyalkylene waxes or polyalkylene glycol waxes. Compounds from other classes which satisfy the above-mentioned softening point requirements may also be used as adhesion promoters. For example, higher esters of phthalic acid, more particularly the dicyclohexyl phthalate commercially available under the name of Unimoll~ 66 (Bayer AG), have proved to be suitable synthetic compounds. Synthetic waxes of lower carboxylic acids and fatty alcohols, for example the dimyristyl tartrate commercially available under the name of Cosmacol~ ETLP (Condea), are also suitable. Conversely, synthetic or partly synthetic esters of lower alcohols with fatty acids from native sources may also be used. This class of substances includes, for example, Tegin~
90 (Goldschmidt), a glycerol monostearate palmitate. Shellac, for example Schellack-KPS-Dreiring-SP (Kalkhoff GmbH), may also be used as an adhesion promoter in accordance with the invention.
In the context of the invention, the waxes also include, for example, the so-called wax alcohols. Wax alcohols are relatively high molecular weight water-insoluble fatty alcohols generally containing about 22 to 40 carbon atoms. The wax alcohols are used as a principal constituent of many natural waxes, for example in the form of wax esters of relatively high molecular weight fatty acids (wax acids). Examples of wax alcohols are lignoceryl alcohol (1-tetracosanol), cetyl alcohol, myristyl alcohol or melissyl alcohol. The adhesion promoters optionally applied in step b) may also contain wool wax alcohols which are understood to be triterpenoid and steroid alcohols, for example the lanolin obtainable, for example, under the name of Argowax~ (Pamentier & Co.). According to the invention, fatty acid glycerol esters or fatty acid alkanolamides and also water-insoluble or substantially water-insoluble polyalkylene glycol compounds may also be used at least partly as a constituent of the adhesion promoters.
In one preferred embodiment, the adhesion promoters used in step b) of the process according to the invention predominantly contain paraffin wax. In other words, at least 50% by weight of the adhesion promoters and preferably more consists of paraffin wax. Paraffin wax contents in the adhesion promoter of about 60% by weight, about 70% by weight or about 80% by weight are particularly suitable, even higher contents of, for example, more than 90% by weight being particularly preferred. In one particular embodiment of the invention, the adhesion promoter applied in step b) consists entirely of paraffin wax.
So far as the present invention is concerned, paraffin waxes have the advantage over the other natural waxes mentioned that the waxes do not undergo hydrolysis in an alkaline detergent environment (as might be expected, for example, in the case of the wax esters), because a paraffin wax does not contain any hydrolyzable groups.
Paraffin waxes consist principally of alkanes and small amounts of iso- and cycloalkanes. The paraffin to be used in accordance with the invention preferably contains virtually no constituents with a melting point above 70°C and, more preferably, above 60°C. If the temperature in the cleaning solution falls below this melting temperature, high-melting alkanes in the paraffin can leave unwanted wax residues behind on the surfaces to be cleaned or the ware to be cleaned. Wax residues such as these generally leave the cleaned surface with an unattractive appearance and should therefore be avoided.
The adhesion promoters used in step b) according to the invention preferably contain at least one paraffin wax with a melting point of about 50°C to about 55°C.
The paraffin wax used preferably has a high content of alkanes, H 3841-I PCT ~ 37 isoalkanes and cycloalkanes solid at ambient temperature (generally about to about 30°C). The higher the percentage of solid wax constituents present in a wax at room temperature, the more useful that wax is as an adhesion promoter in step b) of the process according to the invention. The 5 higher the percentage of solid wax constituents, the greater the resistance of the layer of adhesion promoter to impact or friction with other surfaces which leads to longer lasting adhesion of the coated active substances.
Large percentages of oils or liquid wax constituents can weaken particle adhesion so that the active substances "stuck on" separate from the tablet.
10 Besides paraffin as principal constituent, the adhesion promoters may also contain one or more of the waxes or wax-like substances mentioned above. Basically, the composition of the adhesion promoters should be such that the "adhesive layer" is at least substantially insoluble in water. The solubility in water should not exceed about 10 mgll at a temperature of about 30°C and should preferably be below 5 mg/l.
If temperature-controlled release of the stuck-on active substances is required, the adhesion promoters should have very low solubility in water, even in water at elevated temperature, in order largely to avoid the coated active substances being released independently of temperature.
The adhesion promoters to be applied in step b) of the process may be pure substances or mixtures. In the latter case, the melt may contain varying amounts of adhesion promoters and auxiliaries.
The principle described above facilitates the delayed release of the active substances "stuck on" in step c) at a certain time, for example in the wash cycle of a dishwasher, and may be applied with particular advantage when the main wash cycle is carried out at a relatively low temperature (for example 55°C), so that the active substance is only released from the adhesive layer in the final rinse cycle at relatively high temperatures (ca.
70°C).
However, the principle mentioned may also be reversed so that the active substances) islare released from the adhesive layer more quickly rather than with delay. In the process according to the invention, this may readily be achieved by using dissolution accelerators rather than dissolution retarders as adhesion promoters in step b), so that the active substances stuck on separate from the tablet more quickly rather than more slowly. In contrast to the poorly water-soluble adhesion promoters described above, preferred adhesion promoters for rapid dissolution are highly soluble in water. The solubility of the adhesion promoters in water can be distinctly increased by certain additives, for example by incorporating readily soluble salts or effervescent systems. Quick-dissol-ving adhesion promoters such as these (with or without additions of other solubility improvers) lead to rapid dissolution and release of the active substances at the beginning of the wash cycle.
Rapid dissolution can also be achieved or supported by certain geometric factors. Relevant particulars can be found in the following.
Particularly suitable adhesion promoters for the accelerated release of the active substances from the detergent tablets are the above-mentioned synthetic waxes from the group of polyethylene glycols and polypropylene glycols.
Polyethylene glycols (PEGs) suitable for use in accordance with the invention are polymers of ethylene glycol which correspond to general formula III:
H-(O-CH2-CH2)~-OH (II I) in which n may assume a value of 1 (ethylene glycol) to more than 100,000. A critical factor in evaluating whether a polyethylene glycol is suitable for use in accordance with the invention is the aggregate state of the PEG, i.e. the melting point of the PEG must be above 30°C, so that the monomer (ethylene glycol) and the lower oligomers where n = 2 to about H 3841-I PCT 3g 16 cannot be used because they have a melting point below 30°C. The polyethylene glycols with relatively high molecular weights are polymolecular, i.e. they consist of groups of macromolecules with different molecular weights. Various nomenclatures are used for polyethylene glycols which can lead to confusion. It is common practice to indicate the mean relative molecular weight after the initials "PEG", so that "PEG 200"
characterizes a polyethylene glycol having a relative molecular weight of about 190 to about 210. Under this nomenclature, the standard polyethylene glycols PEG 1550, PEG 3000, PEG 4000 and PEG 6000 may be used for the purposes of the present invention.
Cosmetic ingredients are covered by another nomenclature in which the initials PEG are followed by a hyphen and the hyphen is in turn directly followed by a number which corresponds to the index n in general formula III above. Under this nomenclature (so-called INCI nomenclature, CTFA
International Cosmetic Ingredient Dictionary and Handbook, 5th Edition, The Cosmetic, Toiletry and Fragrance Association, Washington, 1997), PEG-32, PEG-40, PEG-55, PEG-60, PEG-75, PEG-100, PEG-150 and PEG-180, for example, may advantageously be used in accordance with the present invention.
Polyethylene glycols are commercially obtainable, for example under the trade names of Carbowax~ PEG 540 (Union Carbide), Emkapol~ 6000 (ICI Americas), Lipoxol~ 3000 MED (HULS America), Polyglycol~ E-3350 (Dow Chemical), Lutrol~ E4000 (BASF) and the corresponding trade names with higher numbers.
Polypropylene glycols (PPGs) suitable for use in accordance with the invention are polymers of propylene glycol which correspond to general formula IV:

H-(O-CH-CH2)"-OH (lV) where n may assume values of 1 (propylene glycol) to about 1000. As with the PEGs described above, a critical factor in evaluating whether a polypropylene glycol is suitable for use in accordance with the invention is the aggregate state of the PPG, i.e. the melting point of the PPG must be above 30°C, so that the monomer (propylene glycol) and the lower oligomers where n = 2 to about 15 cannot be used because they have a melting point below 30°C.
Besides the PEGs and PPGs preferably used as adhesion promoters, other substances may of course also be used providing they have a sufficiently high solubility in water and a melting point above 30°C.
Preferred processes according to the invention are characterized in that one or more substances from the groups of paraffin waxes, preferably with a melting range of 50°C to 55°C, andlor polyethylene glycols (PEGs) andlor polypropylene glycols (PPGs) and/or natural waxes andlor fatty alcohols islare applied as adhesion promoters in step b).
Besides melts, other substances may be applied as adhesion promoters in step b) of the process according to the invention. These other substances include, for example, concentrated salt solutions which, after application of the active substances, are converted by crystallization or evaporation into an adhesion-promoting salt crust. Supersaturated solutions or solutions of salts in solvent mixtures may of course also be used.
Solutions or suspensions of water-soluble or water-dispersible polymers, preferably polycarboxylates, may also be used as adhesion promoters in step b). These substances were described earlier on for their co-builder properties.
Other particularly suitable adhesion promoters are solutions of water-soluble substances from the group of (acetalized) polyvinyl alcohol, polyvinyl pyrrolidone, gelatin and mixtures thereof.
Polyvinyl alcohols, referred to in short as PVALs are polymers with the following general structure:
[-CHZ-CH(OH)-j~
which also contain small amounts of structural units of the following type:
[-CH2-CH(OH)-CH(OH)-CH2j Since the corresponding monomer, vinyl alcohol, is not stable in free form, polyvinyl alcohols are produced via polymer-analog reactions by hydrolysis and - on an industrial scale - above all by alkali-catalyzed transesterification of polyvinyl acetates with alcohols (preferably methanol) in solution.
PVALs containing a predetermined residual percentage of acetate groups can also be obtained by these industrial processes.
Commercially available PVALs (for example Mowiol~ types, products of Hoechst) are marketed as white-yellowish powders or granules with degrees of polymerization of ca. 500 to 2,500 (corresponding to molecular weights of ca. 20,000 to 100,000 g/mole) and have different degrees of hydrolysis of 98-99 or 87-89 mole-%. Accordingly, they are partly saponified polyvinyl acetates with a residual content of acetyl groups of ca.
1-2 or 11-13 mole-%.
The solubility of PVAL in water can be reduced and thus selectively adjusted to required values by aftertreatment with aldehydes (acetaliz-ation), by complexing with Ni or Cu salts or by treatment with dichromates, boric acid, borax. The rheological properties of PVAL solutions can also be adjusted to the required values by altering the molecular weight or the concentration, depending on how the solution is to be applied as adhesion _ H 3841-I PCT 42 promoter.
Polyvinyl pyrrolidones, referred to in short as PVPs, correspond to the following general formula:

N
~O
n PVPs are produced by radical polymerization of 1-vinyl pyrrolidone.
Commercially available PVPs have molecular weights of ca. 2,500 to 750,000 g/mole and are commercially available as white hygroscopic powders or as aqueous solutions.
Gelatin is a polypeptide (molecular weight ca. 15,000 - >250,000 g/mole) which is mainly obtained by hydrolysis of the collagen present in the skin and bones of animals under acidic or alkaline conditions. The amino acid composition of gelatin largely corresponds to that of the collagen from which it was obtained and varies according to its provenance. The use of gelatin as a water-soluble capsule material is particularly widespread in pharmacy (hard or soft gelatin capsules).
Adhesion promoters from the group of starch and starch derivatives, cellulose and cellulose derivatives, more especially methyl cellulose, and mixtures thereof are also preferred for the purposes of the present invention.
Starch is a homoglycan in which the glucose units are attached by D-glycoside bonds. Starch is made up of two components of different molecular weight, namely ca. 20-30% straight-chain amylose (molecular weight ca. 50,000 to 150,000) and 70-80% of branched-chain amylopectin (molecular weight ca. 300,000 to 2,000,000). Small quantities of lipids, phosphoric acid and rations are also present. Whereas the amylose - on account of the bond in the 1,4-position - forms long, helical intertwisted chains containing about 300 to 1,200 glucose molecules, the amylopectin chain branches through a 1,6-bond after - on average - 25 glucose units to form a branch-like structure containing about 1,500 to 12,000 glucose molecules. Besides pure starch, starch derivatives obtainable from starch by polymer-analog reactions may also be used in accordance with the invention for the production of water-soluble bags. Such chemically modified starches include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms were substituted.
However, starches in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as starch derivatives. The group of starch derivatives includes, for example, alkali metal starches, carboxymethyl starch (CMS), starch esters and ethers and amino starches.
Pure cellulose has the formal empirical composition (C6H~o05)" and, in formal terms, is a (3-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules of glucose. Suitable celluloses consist of ca. 500 to 5,000 glucose units and, accordingly, have average molecular weights of 50,000 to 500,000. Other cellulose-based disintegrating agents which may be used in accordance with the present invention are cellulose derivatives obtainable from cellulose by polymer-analog reactions. Such chemically modified celluloses include, for example, products of esterification or etherification reactions in which hydroxy hydrogen atoms were substituted.
However, celluloses in which the hydroxy groups have been replaced by functional groups that are not attached by an oxygen atom may also be used as cellulose derivatives. The group of cellulose derivatives includes, for example, alkali metal celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and also amino celluloses.
Preferred adhesion promoters, which may be used in the form of an aqueous solution in the process according to the invention, consist of a polymer with a molecular weight in the range from 5,000 to 500,000 dalton, preferably in the range from 7,500 to 250,000 dalton and more preferably in the range from 10,000 to 100,000 dalton. The layer of adhesion promoter present between the individual regions of the tablet after drying of the adhesion promoter preferably has a thickness of 1 to 150 Nm, preferably 2 to 100 Nm, more preferably 5 to 75 Nm and most preferably 10 to 50 pm.
The third step of the process comprises applying active substances to one or more surfaces of the tablet optionally provided with adhesion promoters. The active substances may be applied to one or more or to all the surfaces of the tablet in solid, highly viscous or plastic form.
The application of solid active substances to the surfaces of the tablet produced in step a) and optionally provided with adhesion promoters in step b) is carried out with machinery known, for example, from the confectionery industry. Accordingly, the solid active substances applied in step c) are referred to hereinafter as "crumbs".
The precision with which a certain quantity of more active substance is applied varies according to the dosage and to the shape and size of the crumbs. In the application of crumbs, this dosing precision generally has a certain range or variation of about t10%. Substances which are intended to dissolve quickly in the washing or cleaning process, for example enzymes, have proved to be particularly suitable active substances for the solid crumbs to be applied to the tablet surface.
As already mentioned, the crumbs can be produced in different shapes and sizes. In principle, "crumb sprinkling" is also understood to be the adhesion of a single dosage unit to a tablet surface, this single dosage unit naturally having a higher volume than the individual volume of dosage units repeatedly applied to the tablet. According to the invention, therefore, a hemispherical crumb for example can be stuck onto one surface of an orthorhombic tablet. "Crumbs" and tablets can also be made in other shapes, such as cubes, squares, semiellipsoids, cylinder segments, prisms, etc.
In preferred embodiments of process step c), however, the number of crumbs applied to the tablet is greater than 1. Thus, it can be visually attractive to provide several surfaces of a tablet with a single crumb - in a way extending the above-mentioned principle to a second, third, fourth etc.
surface of the tablet up to the coverage of all surtaces with one or more crumbs.
Since the above-described embodiments involve the selective application of a single crumb to a defined surface of the tablet, the outlay on machinery for carrying out step c) of the process is extremely high in cases such as these. In the interests of process economy, therefore, the crumbs to be applied are preferably much smaller than the tablet itself and are applied in large numbers to one or more surfaces, more than 10 to several hundred crumbs preferably being applied.
Corresponding crumbs thus advantageously have the dimensions of typical detergents in powder, granular, extrudate, flake or platelet form and are "stuck on" in large numbers in step c). In the most simple case, this is done by pressing a surface optionally provided with adhesion promoter into a bed of crumbs. Other embodiments of this step are also possible, i.e. for example dipping a tablet to a percentage of its height into an adhesion promoter and then pressing the tablet into the bed of crumbs. In this wav.
a layered structure can be suggested in the final tablet. The percentage mentioned above is normally between 10 and 50%, preferably between 20 and 40% and more preferably between 25 and 35% of the tablet height.
According to the invention, the entire tablet optionally provided with adhesion promoter may be rolled in an optionally agitated bed of crumbs or the tablet may be dipped into adhesion promoter and then into an optionally agitated bed of crumbs. This results in completely crumb-covered tablets which resemble the rum balls mentioned at the beginning, suitable basic forms being of course not only spheres, but also cubes, squares, orthorhombi, cylinder segments, prisms, etc.
In summary, therefore, preferred processes are characterized in that additional active substance in the form of powders, agglomerates, granules, extrudates, flakes or platelets is applied to one or more surtaces of the tablet in step c).
The application of extrudates in particular may be carried out in a visually attractive manner. Whereas powders, agglomerates and granules have an irregular particle structure which, ideally, is substantially round, extrudates can be produced in any shape. Besides ideally round extrudates, such as Megaperls~ (trademark of Henkel KGaA), extrudates can also be produced in special shapes and applied in step c) of the process according to the invention. Examples of such special shapes are extrudate disks in the form of stars, half moons, trees, animal bodies etc., which look particularly attractive on a tablet surface when they are contrastingly colored.
In the case of tablets where the additional active substance is to be applied in the form of one or more solid dosage units in step c), it is advisable to apply the additional active substance to flat surfaces of the tablet, for example the top andlor bottom surface of cylindrical tablets or one, two, three, four, five or six surfaces of a square tablet. With flat surfaces such as these, it is preferred to apply the additional active substance in several dosage units, as mentioned above. However, it can be of advantage to apply additional active substance in the form of a single dosage unit in cases where the surface is not flat. In other words, the anchorage of additional active substance in the form of a single dosage unit in step c) of the process according to the invention can be supported by a suitable tablet surface. Thus, it is readily possible in accordance with the invention to bond two separately produced tablets designed to interengage or interlock with one another. Besides applying or inserting individual dosage units which have been produced by other processes, for example casting, extrusion, molding, etc., separately produced tablets in particular may serve as a single dosage unit. Accordingly, preferred processes are characterized in that the individual dosage unit is a separately produced tablet.
Besides the simple "stacking" of flat tablets, it is possible in particular here to insert relatively small tablets into cavities of larger tablets preferably provided with adhesion promoter. According to the invention, processes in which the tablet produced in step a) has a cavity into which the individual dosage unit is inserted are preferred. In one particularly preferred embodiment of the present invention, the tablet produced in step a) has a cavity of which the base andlor sides are optionally provided with adhesion promoter, after which a separately produced tablet fitting into the cavity is "stuck" in place. Alternatively, the adhesion promoters may also be applied to individual surfaces of the tablet to be stuck in place.
The cavity in the tablet produced in step a) may assume any shape.
It may extend throughout the tablet, i.e. may have an opening at the top and bottom of the tablet, although it may also be a cavity which does not extend throughout the tablet, i.e. a cavity of which the opening is only visible on one side of the tablet.
In preferred processes, the cavity is a hole, preferably of circular cross-section, through the tablet produced in step a). In one particularly preferred embodiment, the tablet produced in step a) is ring-shaped.
The tablet produced in step a) may assume any geometric form, concave, convex, biconcave, biconvex, cubic, tetragonal, orthorhombic, cylindrical, spherical, cylinder-segment-like, disk-shaped, tetrahedral, dodecahedral, octahedral, conical, pyramidal, ellipsoidal, pentagonal-, heptagonal- and hexagonal-prismatic and rhombohedral forms being particularly preferred. Completely irregular bases, such as arrow and animal shapes, trees, clouds etc. can also be produced. If the tablet produced in step a) has corners and edges, they are preferably rounded off. As an additional optical differentiation, an embodiment with rounded-off corners and bevelled ("chamfered") edges is preferred.
The tablet produced in step a), through which there is a hole in this preferred embodiment, may of course also be produced as a multiphase tablet. In the interests of process economy, two-layered tablets have proved to be particularly effective.
The shape of the hole through the tablet can also be freely selected, preferred tablets being characterized in that the hole has circular, ellipsoidal, triangular, rectangular, square, pentagonal, hexagonal, hepta gonal or octagonal horizontal sections. The hole may also assume completely irregular shapes, such as an-ow or animal shapes, trees, clouds, etc. As with the basic tablets, angular holes preferably have rounded-off corners and edges or rounded-off corners and chamfered edges, The geometric forms mentioned above may be combined as required with one another. Thus, tablets with a rectangular or square base and circular holes can be produced just as well as round tablets with octagonal holes, the various combination possibilities being unlimited. In the interests of process economy and consumer acceptance, particularly preferred holed tablets are characterized in that the base of the tablet and the cross-section of the hole have the same geometric form, for example tablets with a square base and a centrally located square hole. Ring tablets, i.e. circular tablets with a circular hole, are particularly preferred.
If the above-mentioned principle of the hole open on two opposite sides of the tablet is reduced to one opening, the result is a recess tablet.
According to the invention, processes in which the tablet produced in step a) has a recess are also preferred.
As with the "hole tablets", the tablet produced in step a) may again assume any geometric form, concave, convex, biconcave, biconvex, cubic, tetragonal, orthorhombic, cylindrical, spherical, cylinder-segment-like, disk shaped, tetrahedral, dodecahedral, octahedral, conical, pyramidal, ellip-soidal, pentagonal-, heptagonal- and octagonal-prismatic and rhombohedral forms being particularly preferred. The base of the tablet may even assume a completely irregular shape, such as arrow or animal shapes, trees, clouds, etc. If the tablet has corners and edges, they are preferably rounded-off. As an additional optical differentiation, an embodiment with rounded-off corners and chamfered ("bevelled") edges is preferred.
The shape of the recess may also be freely selected, tablets in which at least one recess may assume a concave, convex, cubic, tetragonal, orthorhombic, cylindrical, spherical, cylinder-segment-like, disk shaped, tetrahedral, dodecahedral, octahedral, conical, pyramidal, ellip soidal, pentagonal-, heptagonal- and hexagonal-prismatic and rhombohedral form being preferred. The recess may also assume a totally irregular shape, such as arrow or animal shapes, trees, clouds etc. As with the tablets produced in step a), recesses with rounded-off corners and edges or with rounded-off corners and chamfered edges are preferred.
The recess shapes described in earlier German patent application DE 198 22 973.9 (Henkel KGaA), to which reference is expressly made here, are particularly preferred.
The size of the recess by comparison with the tablet as a whole is governed by the application envisaged for the tablets. The size of the recess can vary according to whether additional active substance applied or introduced in step c) is intended to contain a relatively small or relatively large quantity of active substance. Irrespective of the intended application, preferred detergent tablets are characterized in that the ratio by weight of the basic tablet to the recess filling is in the range from 1:1 to 100:1, preferably in the range from 2:1 to 80:1, more preferably in the range from 3:1 to 50:1 and most preferably in the range from 4:1 to 30:1.
Similar observations may be made on the contributions made by the basic tablet and the recess filling to the total surface of the detergent tablet.
In preferred detergent tablets, the surface of the pressed-in recess filling makes up 1 to 25%, preferably 2 to 20%, more preferably 3 to 15% and most preferably 4 to 10% of the total surface of the filled tablet.
If, for example, the tablet as a whole has dimensions of 20 x 20 x 40 mm and, hence, a total surface area of 40 cm2, preferred recess fillings have a surface area of 0.4 to 10 cm2, preferably 0.8 to 8 cm2, more preferably 1.2 to 6 cm2 and most preferably 1.6 to 4 cm2.
Entirely analogous considerations in regard to ratio by weight, volume and surface apply of course to the "holed" tablets where the surface is divided between the upper and lower faces of the tablet.
In step b), adhesion promoter is optionally applied to one or more tablet surfaces. In the above-mentioned processes where two tablets are joined together, the adhesion promoter may be applied either to the cavity tablet or to the tablet which fills the cavity. In preferred processes, adhesion promoter is introduced into the cavity of the tablet in step b).
This procedure is particularly suitable for recess tablets because step b) of the process according to the invention can be carried out simply by introducing liquid adhesion promoters dropwise into the recess.
Suitable dosing machines for the industrial dosage of small quantities of liquids into cavities are sufficiently well known to the expert.
In many cases, it is technically simpler to apply adhesion promoter to the tablet filling the cavity. In cases such as these, processes which are characterized in that adhesion promoter is applied to one or more surfaces, preferably to one surface, of the individual dosage unit in step b) are particularly preferred.
The application of adhesion promoter to preferably one surface of the individual dosage unit may be carried out in various ways. For example, the separate dosage unit may be wetted with adhesion promoter on one side by dipping and then placed in the cavity. Although this is easy to do from the technological point of view, it does involve the danger of adhesive soiling the surface of the cavity tablet. In this variant, the quantity of adhesive can be controlled by varying the theological properties of the adhesion promoters.
Another and - according to the invention - preferred method of applying adhesion promoter to preferably one surface of the individual dosage unit comprises moving this dosage unit past adhesive dosing systems and then placing it in the cavity. This can be done by using adhesion promoter nozzles, brushes or fleeces impregnated with adhesion promoters or by rollers. The last of these variants is particularly simple because the separate dosage unit has only a small contact surface with the roller. The adhesion promoter can be added from the interior of the roller, although it may also be applied to the roller at a point remote from the point of contact between the roller and the separate dosage units. Accordingly, processes in which the adhesion promoters) islare applied to one surface of the individual dosage unit, preferably using adhesion-promoter-transferring rollers, brushes or fleeces, are preferred.
The filling of the cavity may completely fill the cavity or alternatively may also project from or only partly fill the cavity, no limits being imposed on the imaginativeness of the product developer. By varying the shape of the tablet with a hole or recess, the shape of the recess or the hole and the shape of the separate dosage unit, it is possible to produce various tablets which, visually, differ considerably from one another. For example, the circular ring tablet with a circular hole described above can be filled with an interengaging cylinder. However, it is also possible, for example, to use a sphere, a square in edge contact only, a three-, five- or six-sided prism or any other irregular shape. Depending on the proposed investment, the separate dosage unit may also assume octahedral, multiple-overlap prismatic or eicosahedral forms.
Both in the case of the hole tablets and in the case of the recess tablets, the adhesion of the separate dosage unit in the cavity decreases with decreasing contact surface. Maximum adhesion between the two tablets is obtained when the ring or recess tablet and the separate dosage unit interengage without any gaps. Accordingly, processes in which the individual dosage unit can be fitted into the cavity of the tablet are preferred.
In complete analogy to the above-described production of two-phase tablets by "sticking" two separately produced tablets onto or into one another, it is also possible to produce three-phase tablets. To this end, three separately produced tablets may be stuck onto or into one another, although it is also possible and preferred to produce a two-phase tablet, for example a two-layer tablet, and then to fit another tablet onto or into the two-phase tablet.
The above-mentioned principle may be extended to other multiphase detergent tablets. For example, four-phase tablets can be produced by joining two two-phase tablets to one another. In the most simple case, this is done in the process according to the invention by separately producing two two-phase tablets, preferably by two-layer tabletting, and then joining the two tablets to one another using adhesion promoters. Four-phase 3:1 tablets can also be produced in this way. The two-phase tablets to be joined together may of course also be produced in another way. For example, one single-layer or multilayer recess tablet can be produced, the recess filled with an active substance (for example in the form of a melt, powder, granules, extrudate, flakes, etc.) and another single-phase, two-phase or three-phase tablet may be applied to the tablet.
There are various possibilities - for example a two-layer recess tablet of which the recess is filled with a melt or a particulate mixture, another tablet being adhesively applied to that side of the tablet where the recess is located. In this way, the recess in a way becomes the "core" because the filling is now surrounded on all sides. Exactly the same procedure can be applied to a tablet with a hole through it ("ring tablet") which is subsequently "closed" on both sides with another tablet.
The above-mentioned possibilities for fitting tablets onto or into one another may also be used to make the tablet as a whole or parts thereof dissolve more quickly. If, for example, two flat tablets are stuck together with adhesion promoter, water can only reach the adhesion promoter at the edges of the tablet in its undissolved state under in-use conditions. Even where readily water-soluble adhesion promoters are used, the bond can only be broken when part of the tablet as a whole has dissolved.
The disadvantages mentioned above can be overcome by selective application of the adhesion promoter. For example, it is possible and preferred in the joining of two tablets with their flat surfaces not to apply the adhesion promoter to the contact surface, but only to apply "spots" of adhesion promoter along the contact edge or at the corners. Under in-use conditions, these spots are immediately exposed to the washing water so that the two tablets separate more quickly from one another. If two cubic tablets are joined together in this way, the adhesion promoter does not have to be applied along all four edges. Instead, the bond can be made to dissolve even more quickly by applying spots of adhesion promoter to the four corners only. To ensure even faster dissolution, individual spots of adhesion promoter can be omitted, so that for example only two diagonally opposite contact corners are provided with adhesion promoter.
In summary, it may be said that, if fast dissolution of the tablet as a whole or individual parts thereof is required, rapid surface enlargement by dissolution of the adhesive bond is optimal. This may be achieved or supported by selecting a suitable form of adhesive bond. In cases such as these, linear bonding is preferred to surface bonding, spot bonding being particularly preferred.
In addition, the shape of the tablet parts to be joined with the adhesion promoter can also accelerate dissolution. Preferred tablets are characterized in that, after the bond established by the adhesion promoter has been broken, the tablets are able to move freely in relation to one another, i.e. are not ring core tablets, but preferably basic tablets which have "satellite tablets" at their outer faces. The range of suitable geometric forms is virtually unlimited. In the interests of process economy, however, orthorhombic, tetragonal or cubic tablets are preferred. Tablets with a circular base can only be bonded along their generatrix by correspondingly biconcave intermediate elements which, in turn, are fairly difficult to tablet.
Nevertheless, tablets such as these can be fitted together in accordance with the invention.
The linear bonding or spot bonding process can also be simplified by designing the tablets to interengage exactly through their geometry.
Whereas in the case of cylindrical tablets, for example, tablets in contact at their round sides are capable of shifting horizontally, this can be prevented by elevations or depressions on or in the contact surfaces and correspond-ing depressions or elevations in or on the opposite surfaces which facili-tates the precision application of spots of adhesive. Interengaging detergent tablets such as these, which may be bonded to one another in accordance with the present invention, are described in earlier German patent application DE 199 08 057.7, to which reference is expressly made here.
Irrespective of the shape of the tablets) applied as additional active substance c) to the tablet produced in step a), active substance tablets c) containing surfactants are particularly preferred, these surfactants preferably being present in dissolution-retarded form in order to ensure that the ingredients are only released from the compressed portion c) in the final rinse cycle.
Active substance tablets c) of the type in question can be produced, for example, by casting, extrusion or tabletting. In one particularly preferred embodiment, the active substance tablets c) are produced by tabletting particulate compositions. The rinse aid particles described in earlier German patent application DE 199 14 364.1 (Henkel KGaA) have proved to be particularly useful in this regard. These particles which are preferably tabletted consist of 30 to 90% by weight of one or more carrier materials, 5 to 40% by weight of one or more coating materials with a melting point above 30°C, 5 to 40% by weight of one or more active substances and 0 to 10% by weight of other active substances and auxiliaries. Reference is specifically made to the disclosure of this document. Nevertheless, the most important ingredients of these "rinse aid particles" designed to be compressed to active substance tablets are described in the following. Suitable carrier materials a) are any substances which are solid at room temperature. Substances which develop an additional effect in the wash cycle will normally be selected, builders being particularly suitable. In preferred particulate rinse aids to be tabletted, substances from the group of water-soluble detergent ingredients, preferably carbonates, hydrogen carbonates, sulfates, phosphates and the organic oligocarboxylic acids solid at room temperature are present as carrier materials in quantities of 55 to 85% by weight, preferably 60 to 80%
by weight and more preferably 65 to 75% by weight, based on the weight of the particles.
The preferred carrier materials mentioned were described in detail earlier on.
The coating of the solid particles is expected to satisfy various requirements which relate on the one hand to the melting or solidification behavior of the coating and, on the other hand, to the material properties of the coating in the solidified range at ambient temperature. Since the coating is intended permanently to protect the solid particles encapsulated therein against outside influences during transportation and storage, it must show high stability to the impacts occurring, for example, during transportation or refilling processes, particularly to collisions with other particles or vessel walls. Accordingly, the coating should have either at least partly elastic or at least plastic properties in order to react to impact without breaking by elastic or plastic deformation. The coating should have a melting range (solidification range) at temperatures at which the solid particles to be coated are not exposed to significant thermal stressing. On the other hand, however, the melting range must be high enough still to afford the encapsulated particles effective protection at at least slightly elevated temperatures.
It has been found to be of advantage if the coating does not have a sharply defined melting point, as would normally be the case with pure crystalline substances, but rather a melting range possibly covering several degrees Celsius.
The coating preferably has a melting range of about 45°C to about 75°C and, more preferably, about 50°C to about 60°C. This means in the present case that the melting range lies within the temperature range mentioned and does not denote the width of the melting range.
The width of the melting range is preferably at least 1 °C and more preferably about 2 to about 3°C.
The properties mentioned above are generally exhibited by so-called waxes. "Waxes" in the context of the present invention are understood to be any of a number of natural or synthetic substances which generally melt above 40°C without decomposing and, even just above their melting point, are of relatively low viscosity and non-stringing. Their consistency and solubility are dependent to a large extent on temperature.
Waxes are divided into three groups according to their origin, namely: natural waxes, chemically modified waxes and synthetic waxes.
The natural waxes include, for example, vegetable waxes, such as candelilla wax, carnauba wax, Japan wax, esparto grass wax, cork wax, guaruma wax, rice oil wax, sugar cane wax, ouricury wax or montan wax, animal waxes, such as bees wax, shellac wax, spermaceti, lanolin (wool wax) or uropygial fat, mineral waxes, such as ceresine or ozocerite (earth wax), or petrochemical waxes, such as petrolatum, paraffin waxes or microwaxes.
The chemically modified waxes include, for example, hard waxes, such as montan ester waxes, sassol waxes or hydrogenated jojoba waxes.
Synthetic waxes are generally understood to be polyalkylene waxes or polyalkylene glycol waxes. Compounds from other classes which satisfy the above-mentioned softening point requirements may also be used as coating materials. For example, higher esters of phthalic acid, more particularly the dicyclohexyl phthalate commercially available under the name of Unimoll~ 66 (Bayer AG), have proved to be suitable synthetic compounds. Synthetic waxes of lower carboxylic acids and fatty alcohols, for example the dimyristyl tartrate commercially available under the name of Cosmacol~ ETLP (Condea), are also suitable. Conversely, synthetic or partly synthetic esters of lower alcohols with fatty acids from native sources may also be used. This class of substances includes, for example, Tegin~
90 (Goldschmidt), a glycerol monostearate palmitate. Shellac, for example Schellack-KPS-Dreiring-SP (Kalkhoff GmbH), may also be used as a coating material in accordance with the invention.
In the context of the invention, the waxes also include, for example, the so-called Wax alcohols. Wax alcohols are relatively high molecular weight water-insoluble fatty alcohols generally containing about 22 to 40 carbon atoms. The wax alcohols are used as a principal constituent of many natural waxes, for example in the form of wax esters of relatively high molecular weight fatty acids (wax acids). Examples of wax alcohols are lignoceryl alcohol (1-tetracosanol), cetyl alcohol, myristyl alcohol or melissyl alcohol. The coating of the solid particles coated in accordance with the invention may also contain wool wax alcohols which are understood to be triterpenoid and steroid alcohols, for example the lanolin obtainable, for 3U example, under the name of Argowax~ (Pamentier & Co.). According to the invention, fatty acid glycerol esters or fatty acid alkanolamides and also water-insoluble or substantially water-insoluble polyalkylene glycol compounds may also be used at least partly as a constituent of the coating.
Particularly preferred coating materials in the rinse aid particles to be pressed into the recess are those from the group of polyethylene glycols (PEGs) and/or polypropylene glycols (PPGs), polyethylene glycols with molecular weights of 1500 to 36,000 being preferred, those with molecular weights of 2000 to 6000 being particularly preferred and those with molecular weights of 3000 to 5000 being most particularly preferred.
Particularly preferred rinse aid particles contain polyethylene glycols (PPGs) andlor polyethylene glycols (PEGs) as sole coating material. Poly-propylene glycols (PPGs) suitable for use in accordance with the invention are polymers of propylene glycol which correspond to general formula III
above, where n may assume a value of 10 to 2000. Preferred PPGs have molecular weights of 1000 to 10,000 corresponding to values for n of 17 to about 170.
According to the invention, preferred polyethylene glycols (PEGs) are polymers of ethylene glycol which correspond to general formula IV
above, where n may assume a value of 20 to about 1000. The preferred molecular weight ranges mentioned above correspond to preferred ranges for the value of n in formula IV of about 30 to about 820 (more exactly 34 to 818), mare preferably of about 40 to about 150 (more exactly 45 to 136) and, in one particular embodiment, of about 70 to about 120 (more exactly 68 to 113).
In one preferred embodiment, the coating used in the process according to the invention predominantly contains paraffin wax. In other words, at least 50% by weight of the coating and preferably more consists of paraffin wax. Paraffin wax contents in the coating of about 60% by weight, about 70% by weight or about 80% by weight are particularly suitable, even higher contents of, for example, more than 90% by weight H 3841-I PCT 5g being particularly preferred. In one particular embodiment of the invention, the coating consists entirely of paraffin wax.
So far as the present invention is concerned, paraffin waxes have the advantage over the other natural waxes mentioned that the waxes do not undergo hydrolysis in an alkaline detergent environment (as might be expected, for example, in the case of the wax esters), because a paraffin wax does not contain any hydrolyzable groups.
Paraffin waxes consist principally of alkanes and small amounts of iso- and cycloalkanes. The paraffin to be used in accordance with the invention preferably contains virtually no constituents with a melting point above 70°C and, more preferably, above 60°C. If the temperature in the cleaning solution falls below this melting temperature, high-melting alkanes in the paraffin can leave unwanted wax residues behind on the surfaces to be cleaned or the material to be cleaned. Wax residues such as these generally leave the cleaned surface with an unattractive appearance and should therefore be avoided.
The coating according to the invention preferably contains at least one paraffin wax with a melting point of about 50°C to about 55°C.
The paraffin wax used preferably has a high content of alkanes, isoalkanes and cycloalkanes solid at ambient temperature (generally about 10 to about 30°C). The higher the percentage of solid wax constituents present in a wax at room temperature, the more useful that wax is for the purposes of the present invention. The higher the percentage of solid wax constituents, the greater the resistance of the coating to impact or friction with other surfaces, which leads to longer lasting protection of the coated solid particles. Large percentages of oils or liquid wax constituents can weaken the coating so that pores are opened and the coated particles are thus exposed to the outside influences mentioned.
Besides paraffin as principal constituent, the coating may also contain one or more of the waxes or wax-like substances mentioned above.

Basically, the composition of the mixture forming the coating should be such that the coating is at least substantially insoluble in water. The solubility of the coating in water should not exceed about 10 mgll at a temperature of about 30°C and should preferably be below 5 mgll.
At all events, however, the coating should have low solubility in water, even in water at elevated temperature, in order largely to avoid the coated solid particles being released independently of temperature.
The principle described above facilitates the delayed release of ingredients at a certain time in the wash cycle and may be applied with particular advantage when the main wash cycle is carried out at a relatively low temperature (for example 55°C), so that the active substance is only released from the rinse aid particles in the final rinse cycle at relatively high temperatures (ca. 70°C).
Preferred particulate rinse aids capable of being compressed in accordance with the invention to form active substance tablets c) are characterized in that they contain one or more substances with a melting range of 40°C to 75°C as coating material in quantities of 6 to 30% by weight, preferably 7.5 to 25% by weight and more preferably 10 to 20% by weight, based on the weight of the particles.
Active substance(s):
The active substances present in the rinse aid particles designed to be compressed in accordance with the invention to form active substance tablets c) may be present both in solid and in liquid form at the processing temperature (i.e. at the temperature at which the particles are produced).
The active substances present in the rinse aid particles perform certain functions. Cleaning pertormance can be improved through the separation of certain substances or through the accelerated or delayed release of additional substances. Accordingly, active substances preferably incorporated in the rinse aid particles are ingredients of detergents which are crucially involved in the washing or cleaning process.
Accordingly, one or more substances from the groups of surfactants, enzymes, bleaching agents, bleach activators, corrosion inhibitors, scale inhibitors, co-builders and/or perfumes are present as active substance in quantities of 6 to 30% by weight, preferably 7.5 to 25% by weight and more preferably 10 to 20% by weight, based on the weight of the particles, in rinse aid particles preferably designed for compression to active substance tablets c).
By incorporating surfactants in molten coating material, it is possible to prepare a melt suspension or emulsion which provides additional detersive substance at a predetermined time in the final rinse aid particles or in the final tablets according to the invention. For example, it is possible in this way to produce tablettable rinse aid particles for dishwashers which only release the additional surfactant from the tablet according to the invention at temperatures which domestic dishwashers only reach in the final rinse cycle. In this way, additional detergent is available in the final rinse cycle to accelerate drainage of the water and thus effectively to prevent stains on the tableware. Thus, with a suitable quantity of solidified melt suspension or emulsion in the rinse aid particles, there is no longer any need to use the additional rinse aid typically encountered today.
Accordingly, in rinse aid particles preferably designed for compression to active substance tablets c), the active substances) is/are selected from the group of nonionic surfactants, more particularly alkoxylated alcohols. These substances have already been described in detail.
Another class of active substances which may be incorporated with particular advantage in the rinse aid particles tablettable in accordance with the invention are bleaching agents. In their case, particles can be produced and compressed to active substance tablets c) which only release the bleaching agent on reaching certain temperatures, for example fully compounded detergents which clean enzymatically in the prerinse cycle and only release the bleaching agent in the main wash cycle.
Dishwasher detergents can also be produced in such a way that additional bleaching agents are released in the final rinse cycle so that difficult stains, for example tea stains, are more effectively removed.
Accordingly, in particulate rinse aid particles designed for compression to active substance tablets c), the active substances) islare selected from the group of oxygen or halogen bleaching agents, more particularly chlorine bleaching agents. These substances have also been described in detail.
Another class of compounds which may preferably be used as active substances in the rinse aid particles compressible in accordance with the invention are bleach activators. The important representatives of this group were also described earlier on. Rinse aid particles preferably designed for compression to active substance tablets c) in accordance with the present invention contain bleach activators, more particularly from the groups of polyacylated alkylenediamines, more particularly tetraacetyl ethylenedi-amine (TAED), N-acyl imides, more particularly N-nonanoyl succinimide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or iso-nonanoyl oxybenzenesulfonate (n- or iso-NOBS), n-methyl morpholinium acetonitrile methyl sulfate (MMA), as active substance.
In another important embodiment of the present invention, enzyme-containing rinse aid particles are compressed to active substance tablets c) which are subsequently attached to the basic tablet. These rinse aid particles contain the enzymes described in detail earlier on as active substance(s). Particularly preferred particulate particles are those which contain 40 to 99.5% by weight, preferably 50 to 97.5% by weight, more preferably 60 to 95% by weight and most preferably 70 to 90% by weight of one or more coating materials) having a melting point above 30°C, 0.5 to 60% by weight, preferably 1 to 40% by weight, more preferably 2.5 to 30%

by weight and most preferably 5 to 25% by weight of one or more liquid enzyme preparations) dispersed in the coating materials) and 0 to 20% by weight, preferably 0 to 15% by weight, more preferably 0 to 10% by weight and most preferably 0 to 5% by weight and optionally other carrier materials, auxiliaries andlor active substances. The coating materials are preferably polyethylene glycols andlor polypropylene glycols while liquid enzyme preparations have been successfully used as active substances.
Corresponding liquid enzyme concentrates are based either homogene-ously on propylene glycollwater or heterogeneously on a slurry or are present in microencapsulated form. Preferred liquid proteases are, for example, Savinase~ L, Durazym~ L, Esperase~ L and Everlase~ (Novo Nordisk); Optimase~ L, Purafect~ L, Purafect~ OX L, Properase~ L
(Genencor International) and BLAP~ L (Biozym GmbH). Preferred amy-lases are Termamyl~ L, Duramyl~ L and BAN~ (Novo Nordisk); Maxamyl~
WL and Purafect~ HPAm L (Genencor International). Preferred lipases are Lipolase~ L, Lipolase~ ultra L and Lipoprime~ L (Novo Nordisk) and Lipomax~ L (Genencor International).
Such products as Novo Nordisk's SL and LCC, for example, may be used as slurries or microencapsulated liquid products. The commercially available liquid enzyme preparations mentioned contain, for example, 20 to 90% by weight of propylene glycol or mixtures of propylene glycol and water. According to the invention, enzyme particles preferably designed for compression are characterized in that they contain one or more liquid amylase preparations and/or one or more liquid protease preparations.
Perfumes may also be incorporated as active substances in the rinse aid particles to be compressed in accordance with the invention. All the perfumes described in detail earlier on may be used as active substance. Where perfumes are incorporated in the rinse aid particles, detergents which release all or part of the perfume with delay are obtained.
According to the invention, it is possible in this way for example to produce dishwasher detergents where the consumer experiences the perfume note even after the machine has been opened on completion of the program. In this way, the unwanted "alkali smell" characteristic of many dishwasher detergents can be eliminated.
Corrosion inhibitors may also be introduced as active substance into the rinse aid particles, any of the corrosion inhibitors familiar to the expert being suitable. A combination of enzyme (for example lipase) and lime soap dispersant, for example, has been successfully used as a scale inhibitor.
Auxiliaries:
At extremely low temperatures, for example at temperatures below 0°C, the rinse aid particles can disintegrate under impact or friction or during their compression to form the active substance tablet c). In order to improve stability at temperatures as low as these, additives may optionally be incorporated in the coating materials. Suitable additives must be completely miscible with the molten wax, should not significantly alter the melting range of the coating materials, should improve the elasticity of the coating at low temperatures, should generally not increase the permeability of the coating to water or moisture and should not increase the viscosity of the molten coating material to such an extent as to make processing difficult or even impossible. Suitable additives which reduce the brittleness of a coating consisting essentially of paraffin at low temperatures are, for example, EVA copolymers, hydrogenated resin acid methyl esters, poly-ethylene or copolymers of ethyl acrylate and 2-ethylhexyl acrylate.
Another useful additive where paraffin is used as the coating is a surfactant, for example a C~2_~8 fatty alcohol sulfate, used in a small quantity. This additive improves the wetting of the material to be encapsulated by the coating. In one advantageous embodiment, it is added in a quantity of about <5% by weight and preferably < about 2% by weight based on the coating material. In many cases, the effect of adding an additive can be to promote the coating of even those active substances which, without the additive, would generally form a viscous plastic mass of paraffin and partly dissolved active substance after melting of the coating material.
It can also be of advantage to incorporate other additives in the coating material, for example to prevent premature sedimentation of the active substances. This is particularly advisable in the production of the rinse aid particles according to the invention without carrier materials.
Suitable antisedimenting agents, which are also known as antisettling agents, are known from the prior art, for example from the production of paints and printing inks. Sedimentation phenomena and concentration gradients of the substances to be coated during the transition from the plastic solidification range to the solid can be counteracted, for example, by interfacially active substances, waxes dispersed in solvents, montmoril-Ionites, organically modified bentonites, (hydrogenated) castor oil derivatives, soya lecithin, ethyl cellulose, low molecular weight polyamides, metal stearates, calcium soaps or hydrophobicized silicas. Other sub-stances which have the effects mentioned belong inter alia to the group of antifloating agents and thixotropicizing agents and, chemically, may be classed as silicone oils (dimethyl polysiloxanes, methylphenyl polysiloxanes, polyether-modified methylalkyl polysiloxanes), oligomeric titanates and silanes, polyamines, salts of long-chain polyamines and polycarboxylic acids, aminelamide-functional polyesters and aminelamide functional polyacrylates.
Additives from the classes mentioned above are commercially available in large numbers. Commercial products which may advantage-ously be used as additives in the process according to the invention are, for example, Aerosil~ 200 (pyrogenic silica, Degussa), Bentone~ SD-1, SD-2, 34, 52 and 57 (bentonite, Rheox), Bentone~ SD-3, 27 and 38 (hectorite, Rheox), Tixogel~ EZ 100 or VP-A (organically modified smectite, Sudchemie), Tixogel~ VG, VP and VZ (QUAT-charged montmorillonite, Siadchemie), Disperbyk~ 161 (block copolymer, Byk-Chemie), Borchigen~
ND (sulfo-group-free ion exchanger, Borchers), Ser-Ad~ FA 601 (Servo), Solsperse~ (aromatic ethoxylate, ICI), Surfynol~ types (Air Products), Tamol~ and Triton~ types (Rohm 8~ Haas), Texaphor~ 963, 3241 and 3250 (polymers, Henkel), Rilanit~ types (Henkel), Thixcin~ E and R (castor oil derivatives, Rheox), Thixatrol~ ST and GST (castor oil derivatives, Rheox).
Thixatrol~ SR, SR 100, TSR and TSR 100 (polyamide polymers, Rheox), Thixatrol~ 289 (polyester polymer, Rheox) and the various M-P-A~ types X, 60-X, 1078-X, 2000-X and 60-MS (organic compounds Rheox).
The additives mentioned may be used in varying quantities in the rinse aid particles to be compressed in accordance with the invention, according to the coating material and the active substance. The antisettling agents, thixotropicizing agents and dispersants mentioned above are typically used in concentrations of 0.5 to 8.0% by weight, preferably in concentrations of 1.0 to 5.0% by weight and more preferably in concentrations of 1.5 to 3.0% by weight, based on the total quantity of coating material and active substances.
According to the invention, particulate rinse aids preferably designed to be pressed into the recess contain further auxiliaries from the group of antisedimenting agents, antisettling agents, antifloating agents, thixotropi-cizing agents and dispersion aids in quantities of 0.5 to 9% by weight, preferably in quantities of 1 to 7.5% by weight and more preferably in quantities of 1.5 to 5% by weight, based on the weight of the particles.
Particularly in the production of melt suspensions or emulsions containing active substances which are liquid at the processing temper-ature, it is of advantage to use special emulsifiers. It has been found that, above all, emulsifiers from the group of fatty alcohols, fatty acids, polyglycerol esters and polyoxyalkylene siloxanes are particularly suitable.

Further particulars of the production of the rinse aid particles according to the invention are given in the following.
In the context of the invention, fatty alcohols are understood to be the C~~ alcohols obtainable from native fats or oils via the corresponding fatty acids (see below). Depending on the origin of the fat or oil from which they are obtained, these alcohols may be substituted or locally unsaturated in the alkyl chain.
Accordingly, C~~ fatty alcohols, preferably C&22 fatty alcohols, more preferably C~Z_~e fatty alcohols and most preferably C»~8 fatty alcohols are used as emulsifiers in the rinse aid particles according to the invention.
Other suitable emulsifiers are any fatty acids obtained from vegetable or animal oils and fats. Irrespective of their aggregate state, the fatty acids may be saturated or mono- to polyunsaturated. With the unsaturated fatty acids also, the species solid at room temperature are preferred to the liquid or paste-form species. It is of course possible to use not only "pure" fatty acids, but also the technical fatty acid mixtures obtained in the hydrolysis of fats and oils, these mixtures being distinctly preferred from the economic point of view.
For example, individual species or mixtures of the following acids may be used as emulsifiers in accordance with the present invention:
caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, octadecan-12-oleic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, 10-undecenoic acid, petroselic acid, petroselaidic acid, oleic acid, elaidic acid, ricinoleic acid, linolaidic acid, a- and ~i-elaeostearic acid, gadoleic acid, erucic acid, brassidic acid.
It is of course also possible to use the fatty acids with an odd number of carbon atoms, for example undecanoic acid, tridecanoic acid, pentadeca-noic acid, heptadecanoic acid, nonadecanoic acid, heneicosanoic acid, tricosanoic acid, pentacosanoic acid, heptacosanoic acid.
C~22 fatty acids, preferably C$_~ fatty acids, more preferably C,2_,8 ' H 3841-I PCT 68 fatty acids and most preferably C~s.~B fatty acids are used as emulsifiers) in preferred rinse aid particles.
According to the invention, particularly preferred emulsifiers are polyglycerol esters, more particularly esters of fatty acids with poly-glycerols. These preferred polyglycerol esters may be represented by general formula V:
R' HO-(CHZ-CH-CH2-O]"-H ( in which the substituents R' in each glycerol unit independently of one another represent hydrogen or a fatty acyl group containing 8 to 22 and preferably 12 to 18 carbon atoms and n is a number of 2 to 15 and preferably 3 to 10.
These polyglycerol esters are known and commercially available, more especially with degrees of polymerization n of 2, 3, 4, 6 and 10.
Since substances of the type mentioned are also widely used in cosmetic formulations, some of them are also classified in the INCI nomenclature (CTFA International Cosmetic Ingredient Dictionary and Handbook, 5'n Edition, The Cosmetic, Toiletry and Fragrance Association, Washington, 1997). For example, this cosmetic dictionarylhandbook contains information on the keywords POLYGLYCERYL-3-BEESWAX, POLYGLY-CERYL-3-CETYL ETHER, POLYGLYCERYL-4-COCOATE, POLYGLY-CERYL-10-DECALINOLEATE, POLYGLYCERYL-10-DECAnI FATE
POLYGLYCERYL-10-DECASTEARATE, POLYGLYCERYL-2-DIISO-STEARATE, POLYGLYCERYL-3-DIISOSTEARATE, POLYGLYCERYL-10-DISOSTEARATE, POLYGLYCERYL-2-DIOLEATE, POLYGLYCERYL-3-- DIOLEATE, POLYGLYCERYL-6-DIOLEATE, POLYGLYCERYL-10-DIOLE-ATE, POLYGLYCERYL-3-DISTEARATE, POLYGLYCERYL-6-DISTEAR-ATE, POLYGLYCERYL-10-DISTEARATE, POLYGLYCERYL-10-HEPTA-OLEATE, POLYGLYCERYL-12-HYDROXYSTEARATE, POLYGLYCERYL-10-HEPTASTEARATE, POLYGLYCERYL-6-HEXAOLEATE, POLYGLY-CERYL-2-ISOSTEARATE, POLYGLYCERYL-4-ISOSTEARATE, POLY-GLYCERYL-6-ISOSTEARATE, POLYGLYCERYL-10-LAURATE, POLY-GLYCERYLMETHACRYLATE, POLYGLYCERYL-10-MYRISTATE, POLY-GLYCERYL-2-OLEATE, POLYGLYCERYL-3-OLEATE, POLYGLYCERYL-4-OLEATE, POLYGLYCERYL-6-OLEATE, POLYGLYCERYL-8-OLEATE, POLYGLYCERYL-10-OLEATE, POLYGLYCERYL-6-PENTAOLEATE, POLYGLYCERYL-10-PENTAOLEATE, POLYGLYCERYL-6-PENTASTEARATE, POLYGLYCERYL-10-PENTASTEARATE, POLYGLY-CERYL-2-SESQUIISOSTEARATE, POLYGLYCERYL-2-SESQUIOLEATE, POLYGLYCERYL-2-STEARATE, POLYGLYCERYL-3-STEARATE, POLY-GLYCERYL-4-STEARATE, POLYGLYCERYL-8-STEARATE, POLYGLY-CERYL-10-STEARATE, POLYGLYCERYL-2-TETRAISOSTEARATE, POLYGLYCERYL-10-TETRAOLEATE, POLYGLYCERYL-2-TETRA-STEARATE, POLYGLYCERYL-2-TRIISOSTEARATE, POLYGLYCERYL-10-TRIOLEATE, POLYGLYCERYL-6-TRISTEARATE. The commercially obtainable products of various manufacturers which are classified under the above-mentioned keywords in the dictionarylhandbook mentioned above may advantageously be used as emulsifiers in process step b) according to the invention.
Another group of emulsifiers which may be used in the rinse aid particles according to the invention are substituted silicones which carry side chains reacted with ethylene or propylene oxide. These polyalkylene siloxanes may be represented by general formula IV:
R' R' R' H3C- i i-O-[ i I-O]~- i i-CH3 (VI) R' R' R' in which the substituents R' independently of one another represent -CH3 or a polyoxyethylene or polyoxypropylene group -[CH(R2)-CH2-O]XH group, R2 represents -H or -CH3, x is a number of 1 to 100, preferably 2 to 20 and more particularly below 10 and n is the degree of polymerization of the silicone.
The polyoxyalkylene siloxanes mentioned may also be etherified or esterified at the free OH groups of the polyoxyethylene or polyoxypropylene side chains. The unetherified and unesterified polymer of dimethyl siloxane with polyoxyethylene and/or polyoxypropylene is known under the /NCI
nomenclature as DIMETHICONE COPOLYOL and is commercially available under the names of Abil~ B (Goldschmidt), Alkasil~ (Rhone-Poulenc), Silwet~ (Union Carbide), or Belsil~ DMC 6031.
The DIMETHICONE COPOLYOL ACETATE esterified with acetic acid (for example Belsil~ DMC 6032, 6033 and 6035, Wacker) and the DIMETHICONE COPOLYOL BUTYL ETHER (for example KF352A, Sin Etsu) may also be used as emulsifiers in accordance with the invention.
In the same way as the coating materials and the substances to be coated, the emulsifiers may be used over a widely varying range.
Emulsifiers of the type mentioned normally make up 1 to 25% by weight, preferably 2 to 20% by weight and more preferably 5 to 10% by weight of the sum of coating materials and active substances.
According to the invention, particulate rinse aids preferably designed for tabletting additionally contain emulsifiers from the group of fatty alcohols, fatty acids, polyglycerol esters and/or polyoxyalkylene siloxanes in quantities of 0.1 to 5% by weight, preferably in quantities of 0.2 to 3.5%
by weight, more preferably in quantities of 0.5 to 2% by weight and most preferably in quantities of 0.75 to 1.25% by weight, based on the weight of the particles.
An embodiment of the invention in which the active-substance-containing, preferably dissolution-retarded particles were compressed to active substance tablets c) which are subsequently applied to one or more surfaces of the tablets according to the invention was described in the foregoing. The active-substance-containing particles per se may of course also be applied as additional active substance to one or more surfaces of the tablets according to the invention in step c) of the process according to the invention. The particles may be used as active substance c) either directly or after tabletting, depending on whether "crumb-coated tablets"
with numerous relatively small particles or tablets which comprise only one large dosage unit on one surface of the tablet are to be produced.
The particles may be freely selected both in regard to their particle size and in regard to their bulk density and their origin, i.e. the process used for their production. In particular, therefore, dusts, powders, granules, extrudates, agglomerates, compactates, flakes, etc. as particles may either be directly applied as active substance c) or may be tabletted to form an active substance tablet c).
Where fusible substances are used as an ingredient of the additional active substance c), particulate preparations applied either directly or after tabletting to one or more tablet surfaces may also be produced by other processes, which is preferred in accordance with the present invention.
These other processes include, in particular, prilling, pelleting or flaking.
The process preferably used in accordance with the invention for the production of tablettable particles, which is referred to in short as prilling, comprises the production of granules from fusible substances, the melt of the particular ingredients being sprayed in at the top of a tower in the form of droplets of predetermined size which solidify in free fall and collect at the bottom of the tower in the form of granules.
Generally speaking, any gases may be used as the cold gas stream, the temperature of the gas being below the melting temperature of the melt.
In order to avoid long free falls, cooled gases, for example super cooled air or even liquid nitrogen, which are sprayed into the spraying towers, are _ H 3841-I PCT
often used.
The grain size of the prills formed can be varied through the choice of the droplet size, particle sizes of 0.5 to 2 mm and preferably of the order of 1 mm being easy to handle on an industrial scale.
An alternative process to prilling is pelleting. Accordingly, another embodiment of the present invention relates to the production of pelleted detergent components in which a melt is applied to cooled pelleting plates, the pellets being applied immediately afterwards to one or more tablet surfaces or being tabletted beforehand.
Pelleting comprises applying a melt of the particular ingredients to rotating inclined plates which have a temperature below the melting temperature of the melt and are preferably cooled below room temperature.
Process variants where the pelleting plates are supercooled can again be carried out. In this case, however, measures have to taken to prevent the condensation of atmospheric moisture.
Pelleting gives relatively large particles which, in conventional industrial processes, are between 2 and 10 mm and preferably between 3 and 6 mm in size.
The use of cooling rollers represents a more economical variant for the production of particulate detergent components with the composition mentioned from melts. Accordingly, another possible step of the present invention is a process for the production of particulate detergent components in which a melt is applied to or sprayed onto a cooling roller, the solidified melt is scraped off and, if necessary, size-reduced. The particles obtained may then be tabletted for form active substance tablets c) or may be directly used as active substance c). By using cooling rollers, it is readily possible to adjust the required particle size range which, in this process, may even be below 1 mm and, for example, is in the range from 200 to 700 Nm.
However, the active substances to be applied in step c) may be applied to one or more surfaces of the tablet not only in solid form, but also in highly viscous form. To this end, it is of advantage so far as the subsequent handling of the tablets are concerned if the active substance applied in highly viscous form in step c) can be subsequently converted into the solid form, for example by cooling, chemical reaction, hardening, etc.
To carry out this variant of the process according to the invention, the active substance itself does not have to be present in highly viscous form, instead solid or liquid active substance may be embedded in a highly viscous matrix. In the context of the present invention, the expression "highly viscous" characterizes dosable liquids or pastes which have such a high viscosity that the quantity of highly viscous material applied no longer runs down from or soils the tablet surface. The viscosities in question are normally above 1 Pas, preferably above 10 Pas and more preferably above 100 Pas. One advantage of applying active substance in this way is that dosing is accurate to t 1 %.
In order to limit the flow of the highly viscous material on the tablet surface to an acceptable extent, preferred process variants according to the invention are characterized in that process step c) is carried out at temperatures at most 10°C, preferably at most 5°C and more preferably at most 2°C above the solidification temperature of the highly viscous, post-curing melt or paste.
The above-described adhesion promoters, for example, are suitable as highly viscous melts which can be applied to the tablet in step c).
According to the invention, melt suspensions or melt emulsions of active substances in waxes, paraffins, polyethylene glycols, etc. may be applied to one or more tablet surfaces where they solidify through suitable after-treatment (cooling).
Besides the cooling of highly viscous melts to form hard particles on the tablet surface, other curing mechanisms may also be used. Thus, it is also possible in accordance with the invention to use suspensions or _ CA 02299926 2000-03-03 emulsions of active substances in curable matrices for step c), curing taking place for example by radiation (UV light, gamma rays, microwaves) or by chemical reaction (use of hardeners, oxidation, reduction, polymerization, polycondensation, polyaddition, etc.).
If the active substance itself can be melted or otherwise converted into a highly viscous form in which it can be subsequently cured, it is of course possible and preferred not to use additional matrix materials, i.e. to use the active substance on its own.
Preferred processes according to the invention are characterized in that additional active substance in the form of highly viscous post-curing pastes, more particularly melts, is applied to one or more surfaces of the tablet in step c).
An intermediate position between the solids and the (preferably solidifying or curable) highly viscous liquids is occupied by plastic masses which may also be used as a medium for applying active substance in accordance with the present invention. Plastic masses or substances in plastic form in the context of the present invention are understood to be materials which show the phenomenon of plasticity, i.e. undergo permanent deformation on exposure to outside forces. In contrast to so-called pseudoplastic materials, plastic materials have a yield point. Plastic flow only occurs beyond that point. Informally, the above-mentioned cooling melts of waxes or paraffins also show plastic behavior (in the sense of deformability) within a certain temperature range. Strictly speaking, however, the boundary between plasticity and viscosity is known as viscoplasticity.
Other preferred variants of the process according to the invention are characterized in that additional active substance is applied in the form of plastic masses to one or more surfaces of the tablet in step c).
In the same way as the pseudoplastic substances mentioned, plastic substances have the advantage over the active substances to be applied in solid form that step d) of the process, optional post-forming, is particularly easy to cant' out. Accordingly, in one embodiment of the process according to the invention, a dosage unit of a plastic mass is applied to one tablet surface and is firmly pressed onto the surface and at the same time shaped by a mold pressed onto the surface. This step d) is described hereinafter.
Besides applying formable substances to flat tablet surtaces, such substances may also be introduced into cavities of the tablet and fixed therein by the post-forming step d). According to the invention, it is possible, for example, to prill a formable substance and to press the resulting prills onto the tablet. The grills mentioned are preferably pressed into cavities of the tablet, preferably recesses. Prilling is a forminglshaping process known to the expert for the production of granules from fusible substances by solidifying the droplets of a sprayed melt, the substances being sprayed in, for example, at the top of a tower in the form of droplets of predetermined size which solidify in free fall and collect at the bottom of the tower in the form of granules. Alternatively, the melt may even be sprayed onto cooled surfaces. The grills may be further treated, for example surface-treated, before they are pressed onto or into the tablet surfaces or cavities. It is of course also possible to produce pressings from the grills in a preceding process step and then to bond the pressings thus formed to the tablet in step d) of the process according to the invention. If recess tablets are filled with such pressings, the pressings are preferably shaped to fit the recess.
As mentioned above, any detergent ingredients may be applied as active substances to the surface of the tablet in step c), adhesiveness optionally being guaranteed or increased by adhesion promoters and matrix substances. If the corresponding active substances) islare simultaneously removed from the premix to be tabletted in step a), the result is the separation of active substances so that advantageous properties can be imparted to the tablet as a whole. In preferred processes, the active substances) applied to one or more surfaces of the tablet in step c) is/are selected from the group of enzymes, bleaching agents, bleach activators, surfactants, corrosion inhibitors, scale inhibitors, co-builders andlor perfumes. Soil repellent polymers may also be applied with advantage in step c).
In one particularly preferred embodiment, bleaching agents are applied as active substance so that preferred processes are characterized in that the active substances) applied to one or more surfaces to the tablet in step c) is/are selected from the group of oxygen or halogen bleaching agents, more particularly chlorine bleaching agents.
Other substances which have a critical influence on bleaching performance may also be applied with advantage to the tablet surface.
Accordingly, preferred processes are processes in which the active substances) applied to one or more surfaces of the tablet in step c) islare selected from the group of bleach activators, more particularly from the groups of polyacylated alkylenediamines, more especially tetraacetyl ethylenediamine (TAED), N-acyl imides, more particularly N-nonanoyl succinimide imide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyl oxybenzenesulfonate (n- or iso-NOBS), n-methyl morpholinium acetonitrile methyl sulfate (MMA). The described bleach catalysts, such as Mn and Co complexes, etc., may also be analogously used here.
As already mentioned, the process according to the invention enables a single dosage unit of the additional active substance or several dosage units up to several hundred "crumbs" to be applied in step c).
According to the invention, preferred processes are characterized in that the active substance applied in step c) is applied in the form of a single dosage unit of which the volume makes up 0.05 to 1 times, preferably 0.1 to 0.75 times and more preferably 0.15 to 0.5 times the volume the tablet to which the active substance is applied. If several dosage units are to be applied, preferred processes are processes in which the active substance applied in step c) is applied in the form of 2 to 20 dosage units to one or more surfaces of the tablet, the volume of one of these dosage units making up 0.0025 to 0.5 times, preferably 0.005 to 0.375 times and more preferably 0.0075 to 0.25 times the volume of the tablet to which the active substance is applied. In one particularly preferred embodiment of the invention, the entire tablet (or individual surfaces thereof) is coated with "crumbs" so that particularly preferred processes are characterized in that the active substance applied in step c) is applied in the form of more than 20, preferably more than 50 and more preferably more than 100 dosage units to one or more surfaces of the tablet.
In process step d), the active substances applied to the tablet surfaces) are optionally subjected to postforming. This is particularly preferred in cases where one or less dosage units is applied in step c) providing highly viscous or plastic substances were applied there.
Postforming can be carried out by pressing a mould onto the particular tablet surface(s); rollers with a textured surtace may also be allowed to roll over the tablet surface.
Examples Production of dishwasher tablets Process step a): production of tablets Two-layer rectangular tablets were produced by tabletting two different premixes. 75% by weight of the tablets consisted of lower phase and 25% by weight of upper phase. The composition (in % by weight, based on the particular premix) of the two premixes and hence of the two different phases of the recess tablets is shown in the following Table:

Premix 1 Premix 2 lower hase a er hase Sodium carbonate 32.7 -Sodium tri of hos hate 52.0 91.4 Sodium erborate 10.0 -Tetraacet I eth lenediamine 2.5 -Benzotriazole 0.3 -C~2 fatt alcohol + 3E0 2.5 -D a - 0.2 Enz mes - 6.0 Perfume - 0.4 Pol eth lene I col 400 - 2.0 Process step b): optional application of adhesion promoter A melt was prepared by heating paraffin (melting point: 57-60°C) and was applied to the upper surface of the tablet. Alternatively, lower-melting paraffins (Mp.: 50-55°C), PEG 1550 (Mp.: 45-50°C), PEG

(Mp.: 50-56°C), PEG 4000 or mixtures of these substances may be used.
Process step c): application of active substances Different active substances in the form of "crumbs" (diameter 0.5-1 mm) were then applied to the adhesion-promoter-coated tablets. Based on the weight of the tablet, the quantity of active substance applied was 2% by weight. By allowing the tablets to cool to room temperature, a firmly adhering layer of crumbs was formed on the surface. The comparison tablets C were not provided with active substance, but were left to cool without any further additions.
The additives introduced into the tablets produced in step a) (% by weight, based on the additive-free tablet) are shown in the following Table:

H 3841-I PCT 7g Adhesion romoter 1.0 1.0 1.0 Sokalan~ BM 1 2.0 - -BLAP 300 S ** - 2.0 -n-methyl morpholinium acetonitrile methyl sulfate (MMA), ca. 50% on a support (BASF) ** Protease on a support (Henkel) Process step d): aftertreatment The filled tablets were left to cool at room temperature and were then individually packed.
The cleaning performance of tablets E1, E2 and C was then tested by several examiners in several commercial dishwashers. To this end, the tablets were placed in the dispensing compartment of the machine (Bosch SMU 4032) and a 55°C program was carried out after loading of the machine (water hardness: 16°dH). No additional detergents or rinse aids were used in any of the tests.
(1 ) Preparation of the tea soil 16 Liters of cold mains water (16°dH) were heated briefly to boiling point in a water heater. With the lid on, 96 g of black tea in a nylon gauze were allowed to draw for 5 minutes, after which the tea was transferred to an immersion apparatus equipped with a heating system and stirrer.
60 Teacups were immersed 25 times for 1 minute in the prepared tea brew at 70°C. The cups were then removed and placed upside-down on a draining board to dry.

(2) Preparation of the minced meat soil To prepare the "dried-on minced meat", 225 g of minced meat were H 3841-I PCT 8p mixed with 75 g of whole egg and 80 ml of water and the resulting mixture was homogenized with a kitchen mixing spoon. 3 g of the resulting mixture were spread onto a white china plate using a fork and dried for 2 h at 120°C.
To prepare the "burnt-on minced meat", the above-mentioned mixture was spread over glass bowls using a spatula-like rubber wiper and baked on for 10 minutes in a drying oven preheated to 200°C.

(3) Preparation of the egp oils To prepare the yolk soil, 1 g of egg yolk was applied by brush to a brushed side of stainless steel plates (140 cmz). The plates were then dried horizontally for 4 h at room temperature, immersed in boiling water for 30 seconds and then dried for 30 minutes at 80°C.
To prepare the egg/milk soil, 160 g of whole egg (yolk and egg white) and 50 ml of low-fat milk (1.5% fat) were mixed with a whisk and 1 g of the resulting mixture was applied by brush to a brushed side of stainless steel plates (140 cmz). The plates were then dried horizontally for 4 h at room temperature, immersed for 30 seconds in boiling water and then dried for 30 minutes at 80°C.

(4) Test results The cleaning performance of the tablets against the soils prepared as described in (1) to (3) was visually evaluated by experts on a scale of 0 to 10 where a score of "0" means no cleaning and a score of "10" means complete removal of the soils. The results of the cleaning tests are set out in the following Table:

. H 3841-I PCT 81 Boll , E1 E2 C

Tea 1 9.5 6.0 6.0 Burnt-on minced meat 7.0 6.8 7.0 Dried-on minced meat 9.5 9.8 9.5 E olk 5.0 7.2 5.0 E /milk 10.0 10.0 10.0 The results show that tablets E1 and E2 according to the invention are superior to comparison tablets C in their cleaning performance against various soils. Accordingly, the process according to the invention is also suitable for the "revaluation" and performance boosting of tablets.
Example 2 Production of detergent tablets Process step a): production of tablets As in Example 1, two rectangular tablets were produced by tabletting two different premixes. Tablet 1 weighed 18 g while tablet 2 weighed 7 g.
Process step b)' optional application of adhesion promoter A melt was prepared by heating PEG and was applied in the form of spots to the upper surface of tablet 1.
Process step c): application of active substances in solid form Tablet 2 was "stuck" to adhesion-promoter-spotted tablet 1. A two-layer tablet was formed by cooling to room temperature. Comparison tablet C was produced in known manner in a rotary press by tabletting the premixes for tablets 1 and 2 in a ratio of 18:7 grams to form a conventional two-phase tablet.

The dissolving behavior of the two tablets was then determined. To this end, 2 liters of deionized water (25°C) were placed in a glass beaker, the tablets accommodated in a wire basket were immersed in the water and dissolved by stirring with a propeller stirrer (diameter 4.5 cm, 800 r.p.m.). During the immersion of the tablet, a heating source was switched on, heating the water to 55°C at a rate of 3°C per minute and recording the conductivity as a function of time. The two-layer tablet reached maximum conductivity after 12 minutes while the conventional two-phase tablet took 21 minutes. In addition, the two-layer tablet is superior in its cleaning performance against enzymatic soils.

Claims (32)

1. A process for the production of multiphase detergent tablets, characterized in that it comprises the following steps:
a) tabletting a particulate premix, b) optionally applying one or more adhesion promoters to one or more surfaces of the tablet, c) applying more active substance in solid, highly viscous or plastic form, d) optionally aftertreating (postforming) the active substances applied to the surface of the tablet.

2. A process as claimed in claim 1, characterized in that the particulate premix tabletted in step a) contains builder in quantities of 20 to 80% by weight, preferably in quantities of 25 to 75% by weight and more preferably in quantities of 30 to 70% by weight, based on the premix.

3. A process as claimed in claim 1 or 2, characterized in that the particulate premix tabletted in step a) contains surfactant(s), preferably nonionic surfactant(s), in quantities of 0.5 to 10% by weight, preferably in quantities of 0.75 to 7.5% by weight and more preferably in quantities of 1.0 to 5% by weight, based on the premix.

4. A process as claimed in any of claims 1 to 3, characterized in that the particulate premix tabletted in step a) has a bulk density above 600 g/l, preferably above 700 g/l and more preferably above 800 g/l.

5. A process as claimed in any of claims 1 to 4, characterized in that the particulate premix tabletted in step a) has a particle size distribution where less than 10% by weight, preferably less than 7.5% by weight and more preferably less than 5% by weight of the particles are larger than 1600 µm or smaller than 200 µm in size.

6. A process as claimed in claim 5, characterized in that the particulate premix tabletted in step a) has a particle size distribution where more than 30% by weight, preferably more than 40% by weight and more preferably more than 50% by weight of the particles are between 600 and 1000 µm in size.

7. A process as claimed in any of claims 1 to 6, characterized in that multilayer tablets are produced in known manner in step a) by pressing several different particulate premixes onto one another.

8. A process as claimed in claim 7, characterized in that two-layer tablets are produced in step a) by pressing two different particulate premixes, of which one contains one or more bleaching agents and the other one or more enzymes, onto one another.

9. A process as claimed in claim 7 or 8, characterized in that two-layer tablets are produced in step a) by pressing two different particulate premixes, one of which contains one or more bleaching agents and the other one or more bleach activators, onto one another.

10. A process as claimed in any of claims 1 to 9, characterized in that melts of one or more substances with a melting range of 40°C to 75°C are applied as adhesion promoters to one or more surfaces of the tablet in step b).

11. A process as claimed in claim 10, characterized in that one or more substances from the groups of paraffin waxes, preferably with a melting range of 50°C to 55°C, and/or polyethylene glycols (PEG) and/or polypro-propylene glycols (PPG) and/or natural waxes and/or fatty alcohols is/are applied as adhesion promoter(s) in step b).

12. A process as claimed in any of claims 1 to 9, characterized in that concentrated salt solutions are applied as adhesion promoter to one or more surfaces of the tablet in step b).

13. A process as claimed in any of claims 1 to 9, characterized in that solutions or suspensions of water-soluble or water-dispersible polymers, preferably polycarboxylates, are applied as adhesion promoters to one or more surfaces of the tablet in step b).

14. A process as claimed in any of claims 1 to 13, characterized in that additional active substance in the form of powders, agglomerates, granules, extrudates, flakes or platelets is applied to one or more surfaces of the tablet in step c).

15. A process as claimed in any of claims 1 to 13, characterized in that additional active substance in the form of highly viscous post-curing pastes, more particularly melts, is applied to one or more surfaces of the tablet in step c).

16. A process as claimed in any of claims 1 to 13, characterized in that additional active substance in the form of plastic masses is applied to one or more surfaces of the tablet in step c).

17. A process as claimed in any of claims 1 to 16, characterized in that the active substance(s) applied to one or more surfaces of the tablet in step c) is/are selected from the group of enzymes, bleaching agents, bleach activators, surfactants, corrosion inhibitors, scale inhibitors, co-builders and/or perfumes.

18. A process as claimed in claim 17, characterized in that the active substance(s) applied to one or more surfaces to the tablet in step c) is/are selected from the group of oxygen or halogen bleaching agents, more particularly chlorine bleaching agents.

19. A process as claimed in claim 17, characterized in that the active substance(s) applied to one or more surfaces of the tablet in step c) is/are selected from the group of bleach activators, more particularly from the groups of polyacylated alkylenediamines, more especially tetraacetyl ethylenediamine (TAED), N-acyl imides, more particularly N-nonanoyl succinimide imide (NOSI), acylated phenol sulfonates, more particularly n-nonanoyl or isononanoyl oxybenzenesulfonate (n- or iso-NOBS), n-methyl morpholinium acetonitrile methyl sulfate (MMA).

20. A process as claimed in claim 15 or 16, characterized in that process step c) is carried out at temperatures at most 10°C, preferably at most 5°C and more preferably at most 2°C above the solidification temperature of the highly viscous post-curing melt or the paste-form substance.

21. A process as claimed in any of claims 1 to 20, characterized in that the active substance applied in step c) is applied in the form of a single dosage unit of which the volume makes up 0.05 to 1 times, preferably 0.1 to 0.75 times and more preferably 0.15 to 0.5 times the volume the tablet to which the active substance is applied.

22. A process as claimed in claim 21, characterized in that the individual dosage unit is a separately produced tablet.

23. A process as claimed in claim 20 or 21, characterized in that the tablet produced in step a) has a cavity into which the individual dosage unit is inserted.

24. A process as claimed in claim 23, characterized in that the cavity is a hole of preferably circular cross-section through the tablet, a particularly preferred embodiment of the tablet produced in step a) being ring-shaped.

25. A process as claimed in claim 23, characterized in that the tablet produced in step a) has a recess.

26. A process as claimed in any of claims 22 to 25, characterized in that adhesion promoters are introduced into the cavity of the tablet in step b).

27. A process as claimed in claim 22, characterized in that adhesion promoter is applied to one or more surfaces, preferably to one surface, of the individual dosage unit in step b).

28. A process as claimed in claim 27, characterized in that the adhesion promoter(s) is/are applied to one surface of the individual dosage unit, preferably using adhesion promoter-transferring rollers, brushes or fleeces.

29. A process as claimed in any of claims 22 to 28, characterized in that the individual dosage unit is designed to interengage with the cavity of the tablet.

30. A process as claimed in any of claims 1 to 20, characterized in that the active substance applied in step c) is applied in the form of 2 to 20 dosage units to one or more surfaces of the tablet, the volume of one of these dosage units making up 0.0025 to 0.5 times, preferably 0.005 to 0.375 times and more preferably 0.0075 to 0.25 times the volume of the tablet to which the active substance is applied.

31. A process as claimed in any of claims 1 to 20, characterized in that the active substance applied in step c) is applied in the form of more than 20, preferably more than 50 and more preferably more than 100 dosage units to one or more surfaces of the tablet.

32. A process as claimed in any of claims 1 to 31, characterized in that process step d) comprises pressing a mold onto the surface(s) of the tablet to which the active substance has been applied.