JP2016524662A - Method to improve dewatering efficiency in papermaking, increase sheet wet web strength, increase sheet wet strength, and enhance filler yield - Google Patents

Abstract

The present invention provides a method for improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength, and enhancing filler yield in a papermaking process. The method improves the efficiency of a drainage aid or wet web strength aid or wet strength aid by coating at least some of the filler particles with a material that prevents adhesion of the filler material to their additives. . The drainage additive or wet web strength additive or wet strength aid holds the cellulose fibers firmly together and is not wasted on the filler particles.

Description

  The present invention relates to a method for improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength, and enhancing filler yield in a papermaking process. Typically, in the papermaking process, chemicals are added to assist in dewatering the slurry at the wet end, increasing yield and improving wet or dry sheet strength. The wet end of the papermaking process indicates the stage in the papermaking process where the fibers are dispersed in water in a slurry form. The fiber-water slurry is then passed through a drainage and dewatering process to form a wet web. The solid content after this wet forming process is about 50%. The wet web is further dried to form a dry sheet of paper mat. Paper mats contain water and solids, usually 4 to 8% water. The solid portion of the paper mat includes fibers (typically cellulosic fibers) and can also include fillers.

  Fillers are mineral particles that are added to the paper mat during the papermaking process to enhance the opacity and light reflection properties of the resulting paper. Some examples of fillers are described in US Pat. No. 7,211,608. Fillers include inorganic and organic particles or pigments used to increase opacity or brightness, reduce porosity, or reduce the cost of paper or paperboard sheets. Some examples of fillers include one or more of the following: pigments such as kaolin clay, talc, titanium dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, calcium carbonate, and the like.

  Calcium carbonate filler is provided in two forms, GCC (heavy calcium carbonate) and PCC (precipitated calcium carbonate). GCC is a naturally occurring calcium carbonate rock and PCC is a synthetically produced calcium carbonate. Because it has a larger specific surface area, PCC has greater light scattering capability and provides better optical properties to the paper. However, for the same reason, PCC-filled paper mats produce paper with lower dry strength, wet strength and wet web strength than GCC-filled paper.

  Fillers are generally much smaller than fibers so that fillers have a much larger specific surface area than fibers. One of the challenges found to increase the amount of filler in the sheet is that high filler amounts reduce the efficiency of wet end chemicals such as dehydration aids, wet web strength aids and wet strength aids. That is. The present invention provides a novel filler pretreatment, so that the adsorption of wet end chemicals onto the filler surface is reduced, and thus wet end chemicals such as dehydration aids, wet web strength aids and The efficiency of the wet strength aid increased.

  Paper wet web strength is very important to papermakers because increasing paper wet web strength increases machine operability and reduces sheet tearing and machine downtime. Paper wet web strength is a function of the number and strength of bonds formed between the interwoven fibers of a paper mat. Filler particles having a larger surface area are likely to engage their fibers and interfere with the number and strength of their bonds. Because of its larger surface area, PCC fillers hinder their bonding to a greater extent than GCC.

  Paper dewatering efficiency is also very important for papermakers, because decreasing dewatering efficiency on wet webs will increase the steam demand for drying operations and reduce machine speed and production efficiency. Because it's waxy. Dehydration aids are widely used to improve dewatering efficiency for the purpose of reducing energy consumption and increasing machine speed and production efficiency.

US Pat. No. 7,211,608 US Pat. No. 7,125,469 US Pat. No. 7,615,135 US Pat. No. 7,641,776 US Pat. No. 5,221,435 US Pat. No. 6,592,718 US Pat. No. 4,605,702 US Patent Application Publication No. 2005/0161181 US Pat. No. 5,993,670 German Patent Application No. 4029824 German Patent Application Publication No. 3901292

In order to meet the long-standing and unresolved needs identified above, at least one embodiment of the invention relates to a papermaking method comprising a filler, the method comprising:
Providing a blend of filler particles, at least one drainage additive or wet web strength additive or wet strength aid, and a cellulose fiber stock;
Treating the filler particles with the material composition without the cellulose fiber stock;
Combining filler particles with cellulose fiber stock;
Treating the combination with at least one wet strength aid or wet web strength additive or drainage additive, and forming a paper mat from the combination;
Here, at least 10% of the filler particles are precipitated calcium carbonate, at least 10% of the filler particles are heavy calcium carbonate, the cellulose fiber stock includes a plurality of cellulose fibers and water, and the material composition is a paper mat. Enhance the performance of wet strength aids or wet web strength additives or drainage additives in
Here, at least some of the material composition is added to the filler using a rotary mixing device, which is rotated by a drive, placed in a container containing a slurry of filler particles, and associated with a rotational plane. A dispensing head having a dispensing outlet and a mixing blade along which the composition is injected into the slurry along its circumference surrounding the axis of rotation;
Characterized in that the outlet is formed as an opening and the mixing blade is formed as a strip extending at right angles to the plane of rotation and having a length equal to at least half the inner diameter of the slurry pipe;
As well, the composition is delivered to the dispensing head for mixing the composition into the filler slurry.

  Additional features and advantages are described herein and will be apparent from the following detailed description.

  The detailed description of the invention is set forth below with particular reference to the drawings:

1 is a cross-sectional view of an apparatus used to supply the present invention to a slurry of filler particles. 1 is an exploded view of a cross-sectional view of an apparatus used to supply the present invention to a slurry of filler particles.

  For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated. The drawings are merely illustrative of the principles of the invention and are not intended to limit the invention to the particular embodiments illustrated.

  In at least one embodiment of the invention, a method of making a paper containing a filler is provided. In at least one embodiment of the invention, the papermaking method is a step of making a filler blend of PCC and GCC, where PCC occupies at least 10% by weight of the filler and GCC occupies at least 10% of the filler mass. Pre-treating at least some of the filler particles with a wet web strength additive or a drainage aid or a coating that reduces adhesion between the wet strength aid and the filler particles, and filler blends and wet web strength additives Or adding both drainage aid or wet strength aid to the paper mat.

  Adding wet web strength additives or drainage aids or wet strength aids to the paper mat increases the wet web strength of the resulting paper, or enhances drainage, or improves machine speed and operability. It has been known for some time that sheet wet strength is enhanced. Some examples of wet strength aids, wet web strength additives and drainage aids are described in US Pat. Nos. 7,125,469, 7,615,135 and 7,641,776. Yes.

  Unfortunately, it is not practical to add a large amount of wet strength aid or wet web strength additive or drainage aid to compensate for the fragility due to the large amount of filler in the paper mat. One reason is that these additives are expensive and the use of large amounts of additive results in production costs that cannot be survived commercially. In addition, the addition of excessive additives adversely affects the papermaking process and impairs the operability of various forms of papermaking equipment. Furthermore, cellulose fibers can only adsorb limited amounts of wet strength aids or wet web strength additives or drainage aids. This places a limit on the amount of additive that can be used. One reason for this is that wet strength aids or wet web strength additives or drainage aids tend to neutralize the charge of anionic fibers / fillers, and when these charges are neutralized This is because further adsorption of these additives is inhibited.

  When filler is added to the paper mat, the effectiveness of the wet strength aid or wet web strength additive or drainage aid is also reduced. These additives have a tendency to coat the filler particles. The more filler particles that are present, the more additives will coat the filler particles and thus less wet strength aids or wet web strength additives or freezing agents can be used to bind the cellulose fibers together. . Because there is a maximum amount of wet strength aid or wet web strength additive or freezing agent that can be added, more fillers always meant less effective strength additives. This effect is more severe with PCC than GCC because the higher surface area of PCC is coated with more additives than GCC.

  In at least one embodiment of the invention, at least some of the filler particles comprise a material composition to at least partially prevent adhesion of wet strength aid or wet web strength additive or drainage aid to the filler particles. Preprocessed with. The pretreatment contemplates completely coating some or all of the one or more filler particles with the material composition. In other cases, the pre-treatment involves applying the material composition to only a portion of one or more filler particles, or completely coating some filler particles, and applying the material composition to some other It is intended to apply to only a part of the particles. In at least one embodiment, the pretreatment is performed using at least some of the material compositions described in US Pat. No. 5,221,435, in particular the cationic charge bias species described therein. In at least one embodiment, the pretreatment is performed using a diallyl-N, N-disubstituted ammonium halide-acrylamide copolymer as described in US Pat. No. 6,592,718.

  Although pretreatment of filler particles is known in the art, prior art methods for pretreatment of filler particles include wet strength aids or wet web strength additives or drainage aids to filler particles. Not directed to the effect on adhesion. In fact, many prior art pretreatments increase the adhesion of strength additives to filler particles. For example, US Pat. No. 7,211,608 describes a method of pretreating filler particles with a hydrophobic polymer. However, this pretreatment does not help the adhesion between the strength additive and the filler particles and only repels water to balance the excess water absorbed by the strength additive. In contrast, the present invention reduces the interaction between wet strength aids or wet web strength additives or drainage aids and filler particles, and is unexpectedly large in paper strength, sheet dewatering and machine availability. An increase is obtained.

  When the wet tensile strength of a given paper is compared against the percentage of filler relative to the total solids of the paper mat used to produce the given paper, the results show that the sheet has a wet strength aid 63700. It is clearly shown that without the addition of (temporary wet strength aid) it had a very weak wet strength. Velox was able to significantly increase sheet wet strength. Filler pretreatment alone did not increase sheet wet strength. However, the filler pretreatment further enhanced the Velox performance and resulted in higher sheet wet strength.

  Comparing the wet web tensile strength of a given paper with the percentage of filler relative to the total solids of the paper mat used to produce the given paper, the increase in filler content and paper wet web strength The relationship between the decrease is a linear relationship. Without the addition of Nalco dehydration aid (wet web strength aid) 63700, the paper sheet had very poor wet web strength. The sheet wet web strength could be remarkably improved by using Nalco dehydration aid 63700. Filler pretreatment alone had little effect on paper wet web strength. However, filler pretreatment can further enhance the performance of Nalco Dehydration Aid 63700, and an additional 20% wet strength improvement was achieved by filler pretreatment with lower ash. For higher ash content, 63700 performance was enhanced even higher than 20%. This is because the reduced effectiveness of the strength additive trapped in the filler particles has been released by the filler pretreatment.

  At least some of the fillers encompassed by this invention are well known and commercially available. They include any inorganic or organic particles or pigments used to increase opacity or brightness, reduce porosity, or reduce the cost of paper or paperboard sheets. The most common fillers are calcium carbonate and clay. However, talc, titanium dioxide, alumina trihydrate, barium sulfate, and magnesium hydroxide are also suitable fillers. Calcium carbonate includes heavy calcium carbonate (GCC) in dry or dispersed slurry form, chalk, precipitated calcium carbonate (PCC) in any form, and precipitated calcium carbonate in dispersed slurry form. GCC or PCC dispersed slurry forms are typically produced using polyacrylic acid polymer dispersants or sodium polyphosphate dispersants. Each of these dispersants imparts a significant anionic charge to the calcium carbonate particles. Kaolin clay slurry is also dispersed using polyacrylic acid polymer or sodium polyphosphate.

  In at least one embodiment, the treatment material composition is any one or combination of material compositions described in US Pat. No. 6,592,718. In particular, any of the AcAm / DADMAC copolymer compositions described in detail therein are suitable as processing material compositions. An example of an AcAm / DADMAC copolymer composition is product # Nalco-4690 (hereinafter referred to as 4690) manufactured by Nalco Company of Naperville, Illinois.

  The treating substance composition can be a coagulant. The coagulants included in this invention are well known and are commercially available. They may be inorganic or organic. Typical inorganic coagulants include alum, sodium aluminate, polyaluminum chloride or PAC (aluminum chlorohydroxide, aluminum hydroxide chloride, and polyaluminum hydroxychloride). Known), sulfated polyaluminum chloride, polyaluminum silica sulfate, ferric sulfate, ferric chloride, and the like, and blends thereof.

  Some organic coagulants suitable as processing material compositions are formed by condensation polymerization. Examples of this type of polymer include epichlorohydrin-dimethylamine (EPI-DMA), and EPI-DMA ammonia cross-linked polymer.

  Additional coagulants suitable as processing material compositions include ethylene dichloride and ammonia, or ethylene dichloride and dimethylamine, with or without addition of ammonia, polyfunctional amines such as diethylenetriamine, tetraethylenepenta Mention may be made of condensation polymers with ethylene dichloride and polymers produced by condensation reactions, such as melamine formaldehyde resins, such as min, hexamethylenediamine.

  Additional coagulants suitable as processing material compositions include cationically charged vinyl addition polymers such as (meth) acrylamide, diallyl-N, N-disubstituted ammonium halides, dimethylaminoethyl methacrylate and its four. Quaternary ammonium salt, dimethylaminoethyl acrylate and its quaternary ammonium salt, methacrylamidopropyltrimethylammonium chloride, diallylmethyl (β-propionamido) ammonium chloride, methylsulfuric acid (β-methacryloyloxyethyl) trimethylammonium, quaternized polyvinyl Polymers, copolymers of lactams, vinylamines, and acrylamides or methacrylamides (reacted to produce Mannich or quaternary Mannich derivatives), and Porima, and the like. Preferred quaternary ammonium salts may be formed using methyl chloride, dimethyl sulfate, or benzyl chloride. The terpolymer may comprise an anionic monomer such as acrylic acid or 2-acrylamido 2-methylpropane sulfonic acid as long as the overall charge on the polymer is cationic. The molecular weights of both these polymers, vinyl additions and condensations range from as low as hundreds to as high as millions. Preferably, the molecular weight range is from about 20,000 to about 1,000,000. In at least one embodiment, the pretreatment is pre-made with any one, some, or a combination of any of the material compositions described as suitable material compositions for pretreating filler particles. .

  In at least one embodiment, the wet strength aid or wet web strength additive or drainage aid has the same charge as the material composition suitable for treating the filler particles. If the two have the same charge, the filler additive is less likely to adsorb wet strength aid, wet web strength additive or drainage aid on its surface. Wet strength aids, wet web strength additives or drainage aids encompassed by the invention are those of the substance compositions described in US Pat. No. 4,605,702 and US Patent Application Publication No. 2005/0161181. Any one, particularly the various glyoxylated acrylamide / DADMAC copolymer compositions described therein. An example of a glyoxylated acrylamide / DADMAC copolymer composition is product #Nalco 63700 (manufactured by Nalco Company, Naperville, Ill.). Another example is an amine-containing polymer including allylamine / acrylamide copolymer and polyvinylamine, another example is polyamide-polyamine-epichlorohydrin (PAE).

  In at least one embodiment, the filler used is PCC, GCC, and / or kaolin clay. In at least one embodiment, the filler used is PCC, GCC, and / or kaolin clay or blends thereof with a polyacrylic acid polymer dispersant. The ratio of wet strength additive or wet web strength aid or drainage additive to the solid paper mat can be 3 kg additive per ton of paper mat.

  In at least one embodiment, at least some of the filler particles are pretreated using a rotary mixing device. The rotary mixing device comprises a dispensing head constructed and arranged to rotate as the processing chemical is dispersed in the filler particles. In at least one embodiment, the rotary mixing device is the device described in US Pat. No. 5,993,670. The device can mix the flocculant liquid (s) into the process stream, in which case the dispensing head is rotated by the drive, placed in the pipe / conduit (through which the slurry of filler particles flows) and rotated. The dispensing head is associated with a flat surface and has a flocculant outlet and a mixing blade distributed along its circumference surrounding the axis of rotation and is connected to the flocculant liquid delivery conduit.

  In at least one embodiment, the invention also relates to the use of an apparatus for mixing a flocculant liquid, wherein the flocculant liquid is formed by a mixture of an activator and water, wherein n parts are added to 100 parts filler slurry, The solution is added to 100 parts slurry containing the required amount of active agent.

  There are cases where good results are obtained when a device for mixing is placed downstream of the delivery pump or centrifuge in the direction of the filler slurry flow and this device mixes the flocculant liquid and filler with each other. . However, there are a significant number of cases where this is not the case, in which case the mixing device cannot perform sufficient mixing of the flocculant liquid and filler. In a known device of the type described above (DE-05 40 29 824), the flocculant outlet is formed as a hole or nozzle, each mixing blade is formed as a journal-like protrusion, and a mixing blade in a direction perpendicular to the plane of rotation and The exit dimensions are very small compared to the width of the filler slurry stream. In some cases, the flocculant liquid obtained using this apparatus is poorly mixed into the slurry, i.e., the added flocculant liquid is not distributed sufficiently uniformly in the slurry stream behind the apparatus, It is not included in the slurry in an amount necessary for sufficient agglomeration. The object of the present invention is therefore an apparatus of the above type in which better mixing of the flocculant liquid into the slurry is achieved. The device according to the invention achieves this object, the flocculant outlet is formed as a slot, the mixing blade is formed as a strip, the mixing blade extends perpendicular to the plane of rotation and is equal to at least half the width of the slurry stream. It has a length.

  In at least one embodiment, only one, some or all of the chemicals added in the pretreatment process are added using a rotating device.

  In at least one embodiment, the structure of the dispensing head of the device achieves improved mixing and dispensing of the flocculant liquid in the slurry. The flocculant liquid exits from all slots in the form of wide strips, into which the following mixing blades are inserted in the direction opposite to the direction of rotation, allowing the flocculant liquid to flow along its edges. Pull out as a mist-like strip and pass through the slurry. The flocculant liquid is delivered through the slot into the slurry as an interrupted rapid flow, and the slots and strips are arranged one after the other in the direction of rotation. Slot and blade length dimensions depend on the diameter of the stream or dispensing head.

  In at least one embodiment, the flocculant slots and strip shaped blades can extend both in the direction of the slurry stream and in a direction substantially perpendicular to the slurry stream. Another embodiment of the invention is possible in which the axis of rotation of the mixing head extends at an angle to the slurry stream. In principle, however, the plane of rotation of the mixing head extends substantially in the direction of the slurry stream.

  For example, each slot of two or more slot sections arranged in a row is formed. However, it is particularly effective and advantageous if each slot is continuous along its entire length. This prevents clogging and undesirably high exit velocity of the flocculant liquid.

  Each strip-shaped mixing blade is divided, for example, with a comb-like radial cut along its length. However, it is particularly effective and advantageous if each strip-shaped mixing blade is continuous over its length. This improves the rigidity of the strip-shaped mixing blade and improves the mixing action.

  The cross section of each outlet slot can be varied along its length to control the amount of flocculant liquid exiting. It is particularly effective and advantageous if the cross section of each outlet slot is increased towards the center when viewed along its length. This shape of the outlet slot is used when the slot extends at right angles to the stream direction because there is more slurry in the middle of the slurry pipe than on the sides. Having a uniform slot width achieves uniform delivery of the flocculant into the slurry.

  In at least one embodiment, the slot forming the outlet for the flocculant liquid has a width of, for example, 7-9 mm. The larger the amount of flocculant liquid delivered per unit time, the wider the slot, and the smaller the amount of flocculant liquid delivered per unit time, the narrower the width.

  It is particularly effective and advantageous if the edge of each strip-shaped mixing blade extends substantially parallel to the inner contour of the slurry pipe and a clearance is formed therebetween. A radially extending elongated strip-shaped mixing blade improves the mixing action. However, clearance must remain between the mixing blade and the slurry conduit, and the clearance is large enough to allow the passage of stone pieces present in the slurry.

  This clearance is particularly important and increases when the strip-shaped mixing blade extends perpendicular to the stream. If the strip-shaped mixing blade extends perpendicular to the stream, the clearance is preferably smaller in the direction of the axis of rotation than in the direction perpendicular to the axis of rotation.

  A particularly effective and advantageous embodiment of the invention is obtained if the direction of rotation of the dispensing head drive can be changed. In the device according to the invention, the mixing blade is relatively large or protrudes with respect to the slurry pipe cross section, so that if the dispensing head rotates for a long time in the same direction, clogging with hard pieces and fibers or yarns There is a risk of accumulation. Reverse clogging prevents such clogging and accumulation.

  One, two, and / or more flocculant outlets can be provided, for example, between two mixing blades. However, it is particularly effective and advantageous if the outlet slots and strip-shaped mixing blades are alternately present in the direction of rotation. This also improves the mixing process. On the dispensing head, two or more outlet slots and two or more strip-shaped mixing blades are provided in the direction of rotation.

  It is even more particularly advantageous and advantageous if the inner cross section of the slurry pipe in the region of the dispensing head is similar to the farther inner cross section of the slurry pipe. Thus, the apparatus according to the present invention eliminates the narrowing of the slurry pipe, and the associated increase in slurry flow rate. The dispensing head already forms a larger narrowing of the cross section that can be used for the slurry.

  It is particularly effective and advantageous if the dispensing head is formed as a cylindrical tubular section and / or if the outer diameter of the dispensing head is at least equal to 0.4 of the inner diameter of the slurry pipe. This simplifies the structure, improves the rigidity of the dispensing head, and the outlet slot shape and the strip-shaped mixing blade show increased demands on the rigidity of the dispensing head.

  The dispensing head is passed through a rotatably supported connecting tube, the connecting tube extends away from the slurry pipe, is connected to the drive and flocculant liquid delivery conduit, and is further provided with an inlet opening in the connecting chamber. A particularly effective and advantageous embodiment of the invention is formed when it is rotatably supported and an aggregating agent delivery conduit is opened in the connection chamber. This mode of delivery of the flocculant liquid to the rotatable dispensing head ensures increased rigidity of the connecting tube and its support by simple means. This is possible in the apparatus according to the invention due to the “stone crushing” cooperation of the strip-shaped mixing blade and the slurry pipe.

  For sufficient delivery through the outlet slot of the flocculant liquid (s), the flow cross section available for the flocculant liquid (s) is very important. In one embodiment of the invention, all of the outlet slots together have a cross section that is smaller than the previous flow cross section of the flocculant liquid. The overall cross section of the inlet opening is not smaller than the flow cross section in the delivery conduit and connecting tube. The flow cross sections in the distribution head and the connecting tube are similar. The flow cross section of the flocculant liquid can be optimized by the arrangement of the connection tube in the sealed connection chamber.

  It is particularly effective and advantageous when the check valve is arranged in the flocculant liquid delivery conduit, such as when the flocculant liquid before the check valve is not under pressure, for example when the flocculant liquid pump does not operate. Can penetrate the outlet slot. If the flocculant liquid from the flocculant liquid pump is also not under pressure, the seals and bearings in the connection chamber remain lubricated with the flocculant liquid.

  A particularly effective and advantageous embodiment of the invention is obtained when the dispensing head is driven at a rotational speed of 700-2,500 revolutions / minute, preferably 1,000-2,000 revolutions / minute. At this relatively high rotational speed, the desired improved mixing and distribution of the flocculant liquid in the slurry occurs. If the rotational speed is too low, less than 500 revolutions / minute, the flocculant liquid strip or stream will be interrupted. However, at high speeds, too high a cost is required to achieve the desired effect. In known devices of the above type (DE-05 4029824), flocculants stored in reservoirs can be used. Furthermore, it is known that fresh water is added to the available flocculant in liquid or powder form, resulting in about 1% flocculant parent solution (DE-05 39 01 292). The flocculant parent solution is then mixed with 4-10 parts by volume of make-up water at the filling station to obtain the flocculant in the form of a so-called commercial solution. This flocculant is added in an amount of 18-20% of the amount of filler slurry added to the slurry, ie about 20 parts of the flocculant liquid in the form of flocculant material is added to 100 parts of filler particles. The In addition, the flocculant-containing slurry, i.e. the conditioned filler, contains 1/6 of the liquid by further mixing of the flocculant liquid added.

  In known applications, large amounts of water are used for additional processing of the flocculant material, but the use of large amounts of water is expensive. For processing, in addition to an apparatus for obtaining a parent solution, an apparatus for obtaining a commercial solution is required. This device incurs additional costs associated with the device and additional costs associated with driving the device. The flocculant and its water are delivered until well mixed with the slurry, energy is required for delivery and energy delivery is costly. The water component of the flocculant must be delivered to the filter press along with the slurry, pass through the filter press and finally be purified again. Thus, in known applications, the additional cost increase is associated with the water contained in the flocculant liquid.

  The object of the present invention is therefore to improve the above process and eliminate the costs associated with the use of flocculant liquids or increased water content. This object is achieved according to the invention by designing the device according to the invention such that the required amount of flocculant liquid provided for a 100 t filler slurry is a maximum of 3 t.

  It has been found that the use of the dispensing head of the apparatus according to the invention makes it possible to eliminate the water component of the flocculant liquid without eliminating the effectiveness of the flocculant liquid mixed with the slurry. On the other hand, in known applications, a large amount of water component is required to achieve a predetermined effect using a predetermined amount of additive, but a large amount is required when the device of the present invention is used. The water component is not necessary. The water component of the flocculant liquid can be reduced to a very large extent, so that the costs associated with this water content are eliminated accordingly. As less water is needed, less water needs to be pumped and less water needs to be purified.

  The improved effectiveness achieved by the present invention can be explained as follows and does not have to claim that the explanation is correct: the special shape of the mixing blade of the device of the present invention The filler slurry particles are severely broken and the resulting broken pieces form open cracks. The special shape of the flocculant outlet ensures that the flocculant liquid takes the form of a large surface veil, which covers the newly opened cracks, thus mixing the filler and flocculant Will increase. Since the flocculant liquid according to the invention is already mixed in a finely distributed state, it is not necessary to dilute the additive with a larger amount of water, i.e. to increase the water component of the flocculant liquid. Thus, according to a particularly effective and advantageous embodiment of the present invention, the flocculant liquid is used as a parent solution and the additive is mixed with water in a single step. With this embodiment, additional stations for further mixing with water are eliminated.

  1 and 2, in at least one embodiment, the apparatus can be attached to a filler slurry carrying conduit / pipe 1 through which the filler slurry flows in the direction of arrow 2. Has been. The apparatus can be attached to the slurry pipe 1 by means of an elongated flange 3 and includes a connection chamber 4 protruding from the flange 3. From the connection chamber 4 a distribution head 6 extends into the slurry pipe 1 and is provided at the opposite end of the chamber 4 and rotated by a drive 7 formed as an electric motor. A flocculant liquid conduit 8 opens into the chamber 4 and a check valve 9 is disposed in the conduit 8. The dispensing head 6 forms an outlet slot 10 and comprises a mixing strip shaped blade (11).

  The sleeve 14 supports the connecting tube 15 in a shaft extension 12 extending from the drive 7, and in the end wall of the connecting chamber 4 an axial face seal 16 is provided, which is an axial face seal. A shaft extension 13 extends through 16. The connecting tube 15 has a plurality of elongated inlet openings 17 through which the flocculant flows from the connecting chamber into the connecting tube. The connecting tube 15 projects into the connecting chamber 4 through a sliding bearing sleeve 5 provided in the flange 3, and the tubular-shaped dispensing head 6 forms an integral part of the tube 15. The dispensing head 6 is associated with a rotation plane 18 designated by a broken line. Each mixing blade 11 forms an arcuate edge 19, which limits the extent of the slot 20 for a slurry pipe 1 having a circular cross section at the corresponding position of the blade.

  The foregoing can be better understood with reference to the following examples, which are presented for purposes of illustration and are not intended to limit the scope of the invention.

Example 1
1 (i) Filler pretreatment:
A blend of filler particles was obtained from a paper mill. The blend filler was a mixture of 50% PCC and 50% 100% GCC. The filler blend was diluted with tap water to a solid content of 20%. 200 mL of diluted filler blend was placed in a 500 mL glass beaker. Agitation was carried out for at least 30 seconds before addition of the coagulant. The stirrer was a Eurostar digital overhead mixer equipped with an R1342, 50 mm, 4-blade propeller (both from IKA Works, Inc., Wilmington, NC). The coagulant solution was added gradually after the first 30 seconds of mixing under 800 rpm stirring. The coagulant solution used was 4690. The dosage of the coagulant was 1 kg / ton based on the dry filler weight. Stirring was continued at 800 rpm until all of the coagulant was added. Thereafter, the stirring speed was increased to 1500 rpm for 1 minute.

1 (ii) Use of filler:
The furnish was prepared by decomposing commercially available bleached hardwood dry lap. A mixture of 50% PCC and 50% GCC was added to the pulp furnish to achieve different filler amounts in the sheet. 200 ppm Nalco 61067 was used as a yield improver. For pretreatment evaluation, the filler mixture was pretreated with Nalco coagulant 4690, after which the filler was incorporated into the furnish. During the preparation of the handsheet, 3 kg / ton Nalco 63700 was added to improve the sheet wet web strength. We sought to evaluate the effect of filler pretreatment on 63700 press dewatering performance by measuring sheet wet web strength. Required to press the handsheet to a constant solids (50%) by controlling the same pressure level at 60 ° C. and to completely grind the wetsheet in water under 1000 RPM shear force. The sheet wet web strength was compared. Sheet wet web strength was expected to indirectly reflect press dewatering. The results show that the sheet wet web strength could be significantly improved by adding 63700. The filler pretreatment could further enhance the sheet wet web strength with an additional 20% at a lower ash content. For higher ash content, the performance of 63700 was even higher than 20%.

Example 2
A mechanical test was performed in which the papermaking machine made GAB300 at a machine speed of 900 m / min. A composition was provided in which the cellulose fibers were 14% MXW, 3% coated waste paper, 17% SOW, 12% uncoated waste paper, 44% DIP and 10% ONP. The furnish also included GCC. During the test, 15 / ton of Nalcopress dehydration aid 63700, retention aid, sizing agent, and wet end additives including cationic starch were all kept constant.

1) Filler yield enhancement:
4690 was gradually increased from 0.5 kg / ton to 2 kg / ton based on the filler. Online ash was found to gradually increase with the addition of 4690 to the filler pipe. Clearly, an ash point increase of 0.7 from 15.6% to 16.3% was obtained with the filler pretreatment. Historically, in the same grade production, the recorded ash content of DCS was about 12% without the use of Nalco 63700. It should be pointed out that the ash improvement was provided only by the filler ply. Therefore, since the filler ply accounted for half the basis weight of the final product, the increase in ash content in the filler ply was assumed to be about 1.4%. FPAR increased from 70% to 75%, which could explain why the final ash was significantly enhanced.

2) Vapor pressure reduction:
It was also found that the predryer vapor pressure was reduced by filler treatment. The vapor pressure gradually decreased from 2.15 to 2 bar from 10:30 am to 2:00 pm. Even if the press pressure of the first press section and the press pressure of the second press section were reduced from 550 to 470 and 600 to 580, respectively, only the vapor pressure returned to 2.05.

  During the test, the ash increased from approximately 15.6% to 16.3% approximately 1 hour after pre-treatment of the filler and then maintained at the same level for several hours. On the other hand, the vapor pressure continued to decrease for several hours until the press load was reduced. This is believed to indicate that the steam reduction was not due solely to the increase in ash. Moreover, the steam demand reduction of this test comes from the filler ply only. 4690 is applied only to this ply, so the total steam reduction caused by ash increase alone should be small. Therefore, the results showed that filler pretreatment can enhance 63700 performance as a press dehydrating agent or wet web strength aid.

  A person skilled in the art can apply all of the previously described methods to a paper mat containing other non-cellulosic fiber materials, cellulosic and non-cellulosic fiber materials, and / or mixtures of synthetic fiber materials. You will recognize that it is applicable.

  Variations in the composition, operation, and arrangement of the methods of the invention described herein are possible without departing from the concept and scope of the invention as defined in the claims. While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. This disclosure is illustrative of the principles of the invention and is not intended to limit the invention to the particular embodiments described. Furthermore, the invention encompasses any possible combination of some or all of the various embodiments described herein. All patents, patent applications, and other cited materials mentioned elsewhere in this application or in any cited patent, cited patent application, or other cited material are Is incorporated by reference in its entirety. Furthermore, the present invention contemplates embodiments that exclude one, some, or all of the compositions, methods, components, elements, or other parts of any cited material.

  The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and modifications are intended to be included within the scope of the claims, where the term “comprising” means “including, but not limited to”. Those skilled in the art will recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.

  This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art will recognize other equivalents to the specific embodiments described herein, which equivalents are intended to be encompassed by the following claims.

Claims (19)

A papermaking method including a filler,
Providing a blend of filler particles, at least one drainage additive or wet web strength additive or wet strength aid, and a cellulose fiber stock;
Treating the filler particles with the material composition without the cellulose fiber stock;
Combining the filler particles with the cellulose fiber stock;
Treating the combination with at least one wet strength aid or wet web strength additive or drainage additive, and forming a paper mat from the combination,
At least 10% of the filler particles are precipitated calcium carbonate, at least 10% of the filler particles are heavy calcium carbonate, the cellulose fiber stock includes a plurality of cellulose fibers and water, and the substance composition is the paper. Enhance the performance of the wet strength aid or wet web strength additive or drainage additive in the mat,
At least some of the material composition is added to the filler using a rotary mixing device, the device is rotated by a drive, placed in a container containing the slurry of filler particles, and associated with a plane of rotation. A dispensing head, the dispensing head having a dispensing outlet and a mixing blade along its circumference surrounding the axis of rotation through which the composition is injected into the slurry;
The outlet is formed as an opening, and the mixing blade is formed as a strip extending perpendicular to the plane of rotation and having a length equal to at least half the inner diameter of the slurry pipe;
And the composition is delivered to the dispensing head for mixing the composition into the filler slurry.   The method of claim 1, wherein the paper mat is formed by removing some water from the combination.   The method of claim 1, wherein at least some of the calcium carbonate is in one form selected from a list consisting of non-dispersed calcium carbonate, dispersed slurry calcium carbonate, chalk, and any combination thereof.   At least a portion of the calcium carbonate is in the form of a dispersed slurry calcium carbonate, wherein the dispersed slurry calcium carbonate is at least selected from a polyacrylic acid polymer dispersant, a sodium polyphosphate dispersant, a kaolin clay slurry, and any combination thereof. The method of claim 1, further comprising an item.   The method of claim 1, wherein the blend of filler particles is 50% heavy calcium carbonate and 50% precipitated calcium carbonate.   The method of claim 1, wherein the substance composition is a coagulant.   The method of claim 1, wherein the material composition is a coagulant selected from the list consisting of an inorganic coagulant, an organic coagulant, a condensation polymerization coagulant, and any combination thereof.   The method of claim 1, wherein the material composition is a coagulant having a molecular weight range between 200 and 1,000,000.   The substance composition comprises alum, sodium aluminate, polyaluminum chloride, chlorohydroxyaluminum, aluminum hydroxide chloride, polyaluminum hydroxychloride, sulfated polyaluminum chloride, polyaluminum silica sulfate, ferric sulfate, ferric chloride. Iron, epichlorohydrin-dimethylamine (EPI-DMA), EPI-DMA ammonia cross-linked polymer, ethylene dichloride and ammonia polymer, ethylene dichloride polymer, dimethylamine polymer, polyfunctional diethylenetriamine condensation polymer, poly Functional tetraethylenepentamine condensation polymer, polyfunctional hexamethylenediamine condensation polymer, polyfunctional ethylene dichloride condensation polymer, melamine polymer, formaldehyde resin polymer, cationic charged polymer Le addition polymer, and a coagulant selected from the list consisting of any combination thereof, The method of claim 1.   The method of claim 1, wherein the material composition is an AcAm / DADMAC copolymer.   The drainage additive or wet web strength additive or wet strength aid is selected from the list of glyoxylated acrylamide / DADMAC copolymers, polyvinylamine, polyvinylamide, polydiallylamine, and any combination thereof. The method of claim 1.   The ratio of the drainage additive or wet web strength additive or wet strength aid to the solid portion of the paper mat is 0.3 to 5 kg strength additive per ton of paper mat. Method.   The method of claim 1, wherein at least some of the GCC particles are treated with the material composition.   The method of claim 1, wherein none of the PCC particles are treated with the material composition.   The method of claim 1, wherein the paper mat has a solid portion, and the filler particles in the paper mat account for more than 50% of the combined mass of the solid portions of the paper mat.   The method of claim 1, wherein the drainage additive or wet web strength additive or wet strength aid and the material composition have the same charge.   The blend of filler particles comprises one item selected from the list consisting of organic pigments, inorganic pigments, clays, talc, titanium dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, and any combination thereof. The method of claim 1, further comprising: A papermaking method including the use of fillers,
Providing a blend of filler particles, at least one dry strength aid, and a cellulose fiber stock;
Treating the filler particles with the material composition without the cellulose fiber stock;
Combining the filler particles with the cellulose fiber stock;
Treating the combination with at least one dry strength aid, and forming a paper mat from the combination,
At least 10% of the filler particles are in the form of dispersed slurry calcium carbonate,
The cellulose fiber stock includes a plurality of cellulose fibers and water, and the substance composition enhances the performance of the dry strength aid in the paper mat;
At least some of the material composition is added to the filler using a rotary mixing device, the device is rotated by a drive, placed in a container containing the slurry of filler particles, and associated with a plane of rotation. Having a dispensing head, the dispensing head having a dispensing outlet and a mixing blade along its circumference surrounding the axis of rotation through which the composition is injected into the slurry;
The outlet is formed as an opening, and the mixing blade extends perpendicular to the plane of rotation and is formed as a strip having a length equal to at least half the inner diameter of the slurry pipe;
And the composition is delivered to the dispensing head for mixing the composition into the filler slurry. A method for increasing the interaction between drainage additive or wet web strength additive or wet strength aid and cellulose fibers mixed with filler particles, comprising:
Pre-treating the filler particles with the material composition without the cellulose fiber stock;
Combining pre-treated filler particles with cellulose fibers, and treating the combination with at least one drainage additive or wet web strength additive or wet strength aid,
The filler particles are selected from the list consisting of precipitated calcium carbonate, heavy calcium carbonate, and any combination thereof, and the substance composition is the drainage additive or the wet web strength additive or the wet strength aid. Suppresses adhesion of the agent to the filler particles,
At least some of the material composition is added to the filler using a rotary mixing device, the device is rotated by a drive, placed in a container containing the slurry of filler particles, and associated with a plane of rotation. A dispensing head, the dispensing head having a dispensing outlet and a mixing blade along its circumference surrounding the axis of rotation through which the composition is injected into the slurry;
The outlet is formed as an opening, and the mixing blade extends perpendicular to the plane of rotation and is formed as a strip having a length equal to at least half the inner diameter of the slurry pipe;
And the composition is delivered to a dispensing head for mixing the composition into the filler slurry.

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