DE102024107620A1 - Composite molded part with composite molded part core comprising granular molding material, process for its production and its use - Google Patents

Abstract

The invention relates to a composite molded part core comprising a particulate material and an at least partially cured binder which connects particles of the particulate material to one another. The composite molded part core is characterized in that a mass fraction of the at least partially cured binder is ≤ 15 mass percent. The invention also relates to a method for producing a composite material and a molded part comprising such a composite molded part core.

Description

The present invention relates to a composite molded part core comprising a particulate material and an at least partially cured binder which bonds particles of the particulate material together. The invention further relates to a method for producing a composite material, a method for recycling a composite molded part core, and a molded part with such a composite molded part core.

Molded parts made of a granular material, such as sand, are known from the state of the art. In such molded parts, the granular material is fixed by a binding agent so that the molded part permanently retains its shape. The molded part is given the desired shape by filling a molding compound into a negative mold and allowing it to harden (at least partially) in it. Such molded parts are used in many applications. Of particular importance are applications in the kitchen and sanitary area, for example in the form of wash basins or sinks, shower trays and bathtubs.

There are a number of protective rights for such molded parts. For example, reference is made to the documents DE 3832351 A1, DE 4040 602 A1 , DE 44 07 321 A1 , DE 4410526 A1 and DE 199 20 719 A1 referred to.

The above-mentioned examples of intellectual property rights describe positive properties of various sands as well as various fillers, various binders, additives and pigments, as well as various manufacturing processes and/or various molded part geometries.

Molded parts of this type have the advantage that they are almost unlimited in their geometry due to the small size of the sand grains and the variable arrangement of the sand grains in relation to each other. This means that wash basins, sinks, shower trays and bathtubs can be manufactured in geometric shapes that cannot be realized using other techniques.

A large number of particulate fillers are known from the state of the art. A typical average particle size of the filler is in the range of 1 µm to 3 mm. Known fillers include oxides, silicates, phosphates, carbonates, sulfates, glasses, ceramics and amorphous materials. These particles can come from a natural source, be specifically manufactured or be obtained from a recycling process.

For example, this recycled material can consist of shredded polymer-bonded kitchen sinks, wash basins, shower trays or bathtubs based on e.g. quartz, ATH or carbonates as described above. The polymer used in these materials is e.g. polyester or acrylic based.

In the effort to produce products in the most resource-efficient and sustainable way possible, organic fillers based on renewable raw materials are increasingly being used. These include, for example, nut shells or olive stones, which are used as flour or as particles ground to a certain grain size.

However, quartz sand is still predominantly used to produce such molded parts. The average grain size d ₅₀ (sieve analysis or laser diffraction) of the sand particles used is usually in a range of approx. 0.1 - 1.0 mm. The sand can be used in a natural color or colored. If coloring of the molded part is desired even with uncolored sand, the binding agent used can be mixed with organic and/or inorganic pigments.

Optionally, other components can be added to the molding compound. Examples of such additives are fine particulate substances such as quartz powder. Optionally, other minerals, particles of different grain sizes or powders can also be used. The use of so-called organic and/or inorganic rheology additives is also known. One example of such a rheology additive is fine glass beads.

It is also known that fibers can be added to the molding compound. These serve to reduce weight as well as to stabilize and increase strength. In particular, this can reduce waste due to breakage.

Most of the known processes have in common that the particulate components are mixed with a) a resin (syrup) made of polymethyl methacrylate (PMMA) and/or methyl methacrylate (methyl methacrylate, MMA) and cured in molded parts under certain pressure and temperature or b) are cast with polyester (precursors) in casting machines to form molded parts and cured.

The polyester used in b) can optionally also contain a certain amount of MMA. There is also currently an effort to obtain the polymers used from renewable raw materials. Examples of molding compounds with polymers or binders based on renewable raw materials are known.

A major disadvantage of these processes is that the composition from which the molded part is created after the binder has hardened always has a resin content of >25% by mass. The binder content is often even >35% by mass. Since the binder is much more expensive - especially compared to sand - such molded parts are comparatively expensive. This is exacerbated when binders based on renewable raw materials are used, which are even more expensive. However, this is increasingly desired in order to be able to produce molded parts more sustainably and to advertise them accordingly.

Even if molded parts are usually used for several years, the disadvantage is that they cannot be recycled at the end of their useful life, or can only be recycled with great effort. Due to the high polymer/binder content in particular, the reuse of sand with residues of the binder remaining on the individual grains is not possible, or only possible to a very limited extent. This disadvantage cannot be eliminated even by using binders from renewable sources.

The technology described above is nevertheless widely used. Possible reasons include the ability to automate the manufacturing process and the ability to quickly produce molded parts in large quantities. If acrylic resin is used as a binding agent, the molds required are somewhat more expensive to produce, but last longer than corresponding molds for molding compounds with a polyester-based binding agent. Molding compounds with a polyester-based binding agent are therefore used in particular when certain geometries are only to be produced in relatively small quantities, for example in small series.

However, both types of molded parts are overall very mechanically stable and visually and haptically very appealing. They are also very hard, climate and moisture stable, chemically stable, thermally stable, impact and scratch resistant, break-proof and colorfast, and can also withstand constant temperature changes, such as those that occur in kitchen sinks in particular. Due to these advantages, the number of units and thus the sales that can be achieved with such products have increased significantly in recent years for both technologies. Millions of molded parts are brought onto the market worldwide every year.

In order to meet the demand for individual geometries, such molded parts have also been manufactured using 3D printing for a few years. The materials used and usable are essentially the same as those mentioned above, plus furan or phenolic resin binders or inorganic binders, as well as near-surface epoxy resin impregnation, which also acts as a binder, usually followed by mechanical surface treatment with a final coat of paint. This technology offers an extremely wide range of design options in terms of the three-dimensional structure, but compared to the standard process described above, it is characterized as very slow due to the significantly lower number of pieces per unit of time and, as above, very complex to post-process. Accordingly, molded parts manufactured in this way are expensive and only available in comparatively small quantities. Even if the machines used are of the highest technological level, such molds are therefore mainly used in areas where small quantities are required and/or in manufacturing operations. It does not matter whether these molded parts are used as sinks in kitchens or as washbasins, shower trays or bathtubs in the sanitary area.

The task is therefore to provide molded parts that can be manufactured in large quantities at a reasonable price and of sufficient quality. In terms of possible geometries, they should be as flexible as possible as the molded parts known from the state of the art that are manufactured in large quantities. Furthermore, the molded parts should be as inexpensive as possible and be able to be produced in many colors. They should also be as easy to recycle as possible than the molded parts known from the state of the art.

This object is achieved by a composite molded part core which comprises a particulate material and an at least partially cured binder which bonds particles of the particulate material together. Such a composite molded part core is characterized in particular by the fact that a mass fraction of the at least partially cured binder is ≤ 15 mass percent.

Preferably, at least one surface of the composite molded part core is covered at least in sections by a composite molded part shell. This allows the composite molded part core to be protected, for example from mechanical and/or thermal stress or the undesirable penetration of liquid. In particular, it is preferred that all surfaces of the composite molded part core are covered at least in sections by a composite molded part shell, i.e. the composite molded part core is completely covered by a composite molded part shell.

Surprisingly, it was found that such a composite molded part core is sufficiently stable to form a composite molded part core for a molded part according to an embodiment of the present invention. The binder content is usually very low - at least in comparison to the composite materials described in the prior art - and is below 15 percent by mass, usually even significantly lower, preferably ≤ 12 percent by mass, preferably ≤ 10 percent by mass, more preferably ≤ 8 percent by mass, most preferably ≤ 5 percent by mass.

Any information on the binder content preferably refers (throughout the description of the invention) to the mass fraction of the polymer used and/or the polymer precursor in one or more (uncured) precursor(s), for example a molding compound(s), as provided before the molding process.

In a preferred embodiment, the binder content in the composite molded part core is so low that - for example after applying a composite molded part shell and/or impregnation - the mass fraction of all binders and coating agents used in the entire composite molded part is still ≤ 25 mass percent, preferably ≤ 22 mass percent, preferably ≤ 20 mass percent, more preferably ≤ 18 mass percent, most preferably ≤ 15 mass percent. These details preferably relate to the mass fraction of the polymer used, or the sum of the polymers or polymer precursors used, in the total mass of all compositions used to produce the composite molded part, i.e. in particular the compositions used to produce the composite molded part core and optionally the composite molded part shell.

In one variant, the composite molded part shell can additionally be provided with one or more top coatings, which can also have a polymer content. In this case, their polymer content is also included in the previously mentioned ≤ 25 mass percent total polymer content (based on a composite molded part).

It should be noted that all binders/polymers used in the composite molded part can also be different and in a preferred embodiment are different. Preferably, the binder used for the composite molded part core differs from that used to form the composite molded part shell.

In the context of this invention, the term molding compound is understood to mean the composition used to form the composite molded part core.

In the context of this invention, all percentages - unless explicitly stated otherwise - are to be understood as percent by mass.

For the purposes of this invention, all information on grain size - unless explicitly stated otherwise - should be understood as the average grain size d _50. Any information on grain size (i.e. d ₅ , d ₁₀ , d ₅₀ , d ₉₀ , d ₉₅ or others) should - unless explicitly stated otherwise - be understood as determined by sieve analysis and/or laser diffraction. Whether the (average) grain size is to be determined by sieve analysis or laser diffraction depends essentially on the expected average grain size d ₅₀ : A person skilled in the art knows that sieve analysis is suitable for determining the size of larger (average) grain sizes, whereas laser diffraction is suitable for determining the size of smaller (average) grain sizes.

In a preferred embodiment of a composite molded part core, the binding ability of the at least partially cured binder can be reduced by an activator. The activator is ator preferably a temperature application or reagent application, by which a chemical and / or physical reaction can be triggered in or with the binder, by which the composite molded part core itself or the binder can be converted into a subsequent product with reduced binding ability.

A composite mold core therefore preferably has the additional advantage that the composite mold core can disintegrate when exposed to temperature. Such a property is known, for example, from the field of metal casting. There, such a thermally induced disintegration of a casting mold or a casting mold core is often provided for, since such a casting mold or such a casting mold core can disintegrate due to the high temperature of the poured material and the long exposure to temperature. This has the advantage that its residues can be easily removed from the cooled casting. In addition, this enables the sand used for the casting mold or the casting mold core to be fed into a (sand) cycle. This means that the costs of the sand can be kept low. This recycled sand is usually reused in the foundry to produce an external, usually bentonite-bonded mold part.

Analogously, this is also possible with a preferred composite molded part core according to the present invention. For such composite molded part cores and/or molded parts with such a composite molded part core, recycling is therefore also easily possible, since it or its composite molded part core disintegrates when exposed to high temperatures, preferably ≥ 150°C, more preferably ≥ 200°C, more preferably ≥ 250°C, even more preferably ≥ 300°C, most preferably ≥ 400°C. This preferably takes place with (at least partial) decomposition and/or degradation of the binder. In addition or as an alternative to at least one of the aforementioned temperatures, the decomposition of the composite molded part core or even of the entire composite material preferably occurs when exposed to a temperature that is preferably ≤ 1500°C, more preferably ≤ 1250°C, more preferably ≤ 1100°C, even more preferably ≤ 1000°C, most preferably ≤ 750°C. By selecting the decomposition temperature below the stated value, the energy consumption during recycling can be kept acceptable.

A composite molded part core is therefore preferred in which the binding ability of the at least partially cured binder can be reduced by applying heat. The temperature above which the binding ability of the at least partially cured binder is reduced is preferably ≥ 150°C, more preferably ≥ 200°C, more preferably ≥ 250°C, even more preferably ≥ 300°C, most preferably ≥ 400°C. In addition or as an alternative, this temperature is preferably ≤ 1500°C, more preferably ≤ 1250°C, more preferably ≤ 1100°C, even more preferably ≤ 1000°C, most preferably ≤ 750°C.

In addition to thermal stress, mechanical stress can also be applied alternatively or in combination to separate the particles of the particulate material (also referred to herein as "grains") from one another. A single process or a combination of several processes selected from a group that includes coarse crushing (e.g. jaw crushers), fine crushing (e.g. rotating ball mills) or attrition processes (introduction of frictional energy) has proven to be particularly suitable for this purpose. These processes are also particularly suitable for separating the separated particles from binder residues (in parallel to or after the separation of the particles from one another). The processes can be used dry or wet, either in water and/or solvents or mixtures, possibly with cleaning additives. Optionally, separating processes can also be used before, between or after the mechanical treatments, e.g. sieving, sifting, optical sorting or (separation) processes based on density differences.

Both organic and inorganic components have proven to be suitable as binding agents. Polyurethane resin (PU resin) has proven to be particularly suitable for producing a composite molded part core. Polyurethane resin (PU resin) is already used on a large scale as a binding agent in the so-called "cold box process". It is therefore available almost worldwide in large quantities and at affordable prices.

Preferably, the particulate material is mixed with a PU resin, with the polyurethane resin content being approximately 0.5 - 2% by mass. In particular, it is preferred that the particles are coated by mixing with the PU resin and that these coated particles are then brought into the desired geometry and gassed with amine to cure.

In a preferred embodiment, one or more additives are also added to the mixing process.

The PU resin hardens when gassed. After hardening, the particles are connected to one another via resin bridges. Since the cost of the resin (per unit weight) far exceeds that of the sand, it is advantageous to keep the amount of resin used low. One solution to this is to limit the grain distribution of the particulate material. This keeps the specific surface area (or the surface-to-volume ratio) of the particulate material low. Accordingly, the surface area present in the particulate material that must be connected using the resin is comparatively small. This preferred embodiment makes it possible to produce a composite molded part core particularly inexpensively.

A composite molded part core is therefore preferred in which the particulate material comprises sand whose average particle size d ₅₀ (sieve analysis or laser diffraction) is in a range of 5 µm - 10 mm, preferably 10 µm - 5 mm, particularly preferably 20 µm - 1 mm. Of course, the particulate material is not limited to sand, but can additionally or alternatively comprise other particulate substances. However, sand is preferred due to its wide (worldwide) distribution and comparatively low cost. Sand particles are also characterized by great hardness.

In one variant, it may also be desirable to use the quartz content, representative of all forms of crystalline silica, only in a proportion of < 0.1 mass % (based on the total mass of the composition or the composite molded part).

Preferably, for such a variant, only fillers are used which, alone or in the sum of the (various) fillers, have a proportion of crystalline silica < 0.1 wt.%.

In a preferred embodiment, a filler fraction comprises inorganic and/or organic fillers or mixtures thereof, wherein each of the fillers preferably has a sufficiently low crystalline quartz content (of, for example, < 0.1% by mass). The mixing ratio of two fillers can be selected in a ratio between 99.9:0.1 - 0.1:99.9.

Additionally or alternatively, it is preferred that the particulate (granular) material used to produce the composite molded part core has a particle size (d ₅₀ Sedigraph or laser diffraction) ≥ 5 µm, preferably ≥ 10 µm, preferably ≥ 20 µm. Additionally or alternatively, it is preferred that the particulate (granular) material used to produce the composite molded part core has a particle size (d ₅₀ analogous to e.g. sieve analysis)) ≤ 3000 µm, ≤ 2000 µm, preferably ≤ 1000 µm, preferably ≤ 500 µm, preferably ≤ 250 µm, preferably ≤ 200 µm, preferably ≤ 150 µm, preferably ≤ 100 µm.

A composite molded part core is preferred in which the particles of the particulate material (in the context of this invention also occasionally referred to as "filler") are packed as densely as possible. Accordingly, a composite molded part core according to this invention preferably has a particularly dense grain packing. In addition to the advantages already mentioned above, this also makes it possible (alternatively or additionally) to obtain a comparatively smooth (flat) surface of the composite molded part core.

In a preferred embodiment, a particularly smooth (flat) surface of the composite molded part core is achieved by mixing particles of different grain bands and using them together. In this embodiment, the particles of the smaller grain band can fill gaps that remain between the particles of the larger grain band.

If a particularly smooth surface and/or particularly dense packing is desired, it is therefore preferred that the composite molded part core comprises a particulate material which comprises at least two components which differ at least in an average particle size d ₅₀ (sieve analysis or laser diffraction).

Conversely, it is also possible to deliberately use the situation described above to produce a composite molded part core that has increased porosity. In this case, the intention is that gaps between particles of one grain band fraction are not filled by particles of the same or another grain band fraction. This can be advantageous in some cases, as this increased Porosity during subsequent surface treatment, for example, means that a (liquid) surface treatment material can intentionally and specifically penetrate better and deeper into these pores. This can be used, for example, to significantly increase strength if necessary.

In a preferred embodiment of the composite molded part core already described above, a surface of the composite molded part core is covered at least in sections by a composite molded part shell. Such a composite molded part shell preferably comprises a polymer. The composite molded part shell can completely envelop the composite molded part core or only cover individual surfaces or surface portions of the composite molded part core. The surface covered by the composite molded part shell is preferably a surface of the composite molded part core which is exposed to particular stress when the composite material formed therefrom is used and/or which forms a visible side.

The polymer of the composite molded part shell is preferably a solid or liquid or disperse polymer, which is preferably selected from a group and/or is produced from a precursor selected from a group comprising acrylates, styrene acrylates, silanes, silicones, alkanes, alkenes, alkynes, alcohols, urethanes, epoxies, cellulose, methylcellulose, inorganic polymers and mixtures thereof.

It is conceivable, for example, that a composite molded part core is coated with a coating after it has hardened. A coating is a suspension of, for example, a refractory material that can be applied to a composite molded part core surface and improves its properties. Any unevenness that may occur, for example caused by the structure of the sand grains, could be compensated for by such a composite molded part shell (also referred to as a coating or, as above, as a coating).

Similarly, in the case of a composite molded part core, according to a preferred embodiment, it is possible to refine the surface of the composite molded part core. This refinement can form the composite molded part shell or be part of the composite molded part shell. The composite molded part shell can serve, for example, to give the molded part a desired optical property (for example color or gloss) and/or a desired feel and/or mechanical property (scratch/abrasion resistance) and/or chemical and/or thermal resistance.

In order to achieve these additional advantageous properties, the composite molded part shell can, in one variant, additionally be provided with one or more top coatings, which can be based on the above-mentioned polymers.

As an alternative or supplement to the use of quartz sand for producing composite molded part cores, other particulate materials from the prior art are also conceivable. For example, composite molded part cores are conceivable and preferred for some applications, which comprise a particulate material selected from a group comprising feldspar, chromite sand, andalusite, chamotte, cerabeads, olivine, aluminum oxide balls and zircon sand. Furthermore, the use of mixtures of some of these materials, for example feldspar and quartz sand and ceramic balls, is also conceivable and preferred for some applications. Some of the materials used and their properties are shown in Table 1. Table 1: Overview of preferred particulate materials for composite molded part cores and their type Aluminium silicates Material type e.g. feldspar J-Sand Natural mineral mixture Kerphalite KF Natural mineral, processed Cerabeads Sintered ceramics Fireclay Sintered ceramics M-Sand Oxide ceramics Bauxite sand Oxide ceramics R-Sand Natural mineral, processed SiC Non-oxide ceramics

These materials have shown that they are suitable for use alone or in combination with each other or in combination with quartz sand to produce a composite molded part core. They can be considered as non-exclusive examples of the fillers based on oxides, silicates, phosphates, carbonates, sulfates, glasses and ceramics mentioned above.

In an article by Hüttenes-Albertus Chemische Werke GmbH entitled: "Special sands - molding materials for modern core and mold production" by Ulrich Recknagel and Martin Dahlmann, 2008, the advantages and properties of various particulate materials are presented using the example of their use as casting molds. It has been shown that the respective advantages of the various materials or mixtures can also be used in an analogous manner to produce composite molding cores.

For example, the above-mentioned article describes that specially prepared high-quality quartz sands are preferred. These sands are particularly suitable as particulate material for the production of composite molding cores. Thanks to numerous deposits, quartz sand is available in sufficient quantities and at low cost in Germany and many other parts of the world, so that in addition to the technical advantages, there are also cost advantages. The production of composite molding cores can therefore take place almost independently of location and the processes for handling and processing these raw materials have long been established.

In addition, there are already sufficient plant capacities available at various locations for the treatment, processing and conversion of these raw materials on an industrial scale. The known processes can be used in an analogous manner to produce composite molded part cores in large quantities.

Another advantage is that inexpensive molds and processes for producing molded part cores already exist. For example, molds for producing molded parts for the metal casting industry are available in a wide variety of shapes and sizes. It has been shown that such systems can also be used to produce composite molded part cores ranging in size from a few centimeters to several meters. This makes it possible to design and produce composite molded part cores relatively inexpensively and in almost any size and shape.

In a preferred embodiment, the composite molded part core is formed as a positive mold. In particular, such a mold is selected from a group comprising the mold of a kitchen sink, a washbasin, a shower tray, a bathtub and a worktop.

The composite molded part core can be uncolored or colored. In a preferred embodiment, coloring can be achieved by giving at least one fraction of the particulate material a color, for example by applying a pigment beforehand. Alternatively, a particulate material can be used which, due to its type and origin, already has an advantageous color of its own, for example deep black. In addition or as an alternative, a pigment or a dye can also be introduced independently of a fraction of the particulate material used. In a preferred embodiment, a pigment and/or dye is contained in a binder composition.

Alternatively or additionally, it is preferred that a layer of paint is applied to a surface of the composite molded part core. This layer of paint can be part of the composite molded part shell or can itself form the composite molded part shell. Alternatively, the layer of paint can also be transparent, comparable to a clear varnish, for example.

To produce a composite molded part with a composite molded part core as described above, the composite molded part core is preferably provided with at least one layer on at least one surface. This layer forms the composite molded part shell or is part of the composite molded part shell.

The layer can be clear and unpigmented (colorless). In a further embodiment, this layer can contain transparent colored components. In a preferred embodiment, however, the layer comprises a pigment. Preferably, this layer can impart a desired color to the composite molded part.

In addition, a color layer can also be achieved by one or more pigmented or dye-containing top coats.

Preferably, the above-mentioned first and/or further layer and/or composite molded part shell comprises in one embodiment (independently of the other features mentioned above) a polymer and/or a polymer precursor. The polymer and/or the polymer precursor is or preferably comprises a solid or liquid or disperse polymer, oligomer or monomer, which is preferably selected from a group comprising acrylates, styrene acrylates, silanes, silicones, alkanes, alcohols, urethanes, epoxides, celluloses, methylcelluloses, or mixtures thereof and/or can be converted into a substance from this group. Alternatively or additionally, the polymer and/or the polymer precursor can also be inorganic. An inorganic polymer and/or an organic polymer can be used as the only polymer or in combination with one or more other inorganic polymers and/or organic polymers. Combinations of several inorganic polymers, several organic polymers or combinations of one or more inorganic polymers with one or more organic polymers are therefore possible and preferred in some variants.

In a preferred embodiment, a polymer is first formed in the desired form. It therefore does not have to be used as a 1-component system, but in this embodiment is the product of a 2-component system. Such a 2-component system can include a solvent. Preferably, it is water-based or based on an organic solvent or it is a 100% system (i.e. both water- and solvent-free).

Preferably, the composite molded part shell comprises an additive, wherein the additive preferably comprises a coloring component, preferably a dye, a color paste and/or a pigment and/or the additive has a Mohs hardness > 4, preferably > 4.5, more preferably > 5.

Preferably, the composite molded part shell comprises several layers. These can each give the composite molded part different properties. For example, it is conceivable that one layer gives the molded part a desired optical effect (for example color or gloss), while another layer increases scratch resistance, provides a desired feel, improves fracture resistance, improves hot-cold cycling resistance, increases chemical resistance and/or improves (UV) light resistance.

Of course, a single layer can also give the composite molded part several of the aforementioned desired effects. For example, a single layer can contain pigments or dyes as well as other components that have another positive effect, such as fine fillers (which fill gaps between particles and improve the smoothness (and thus the shine) but also the feel and possibly also the UV barrier properties of the layer). Other additives such as silanes or silicones can also be included in such a layer, which can also improve the feel, the shine and/or the bond to an adjacent layer, as well as lead to a desired hydrophobicity, e.g. the so-called lotus effect. Finally, additives can also be introduced which give the surface a biocidal, e.g. bactericidal effect.

If there are several layers, they can be applied together or at different times or locations. For example, it is conceivable that after applying a layer, this layer is first cured and only then is another layer applied.

Preferably, a layer is cured after it has been applied. This is preferably done by gassing, UV exposure, light exposure, IR exposure and/or thermal treatment. An example of such a layer is a thermally curable varnish and/or a powder coating.

Preferably, a layer is applied to the composite molding core (or previously applied layers) by brushing, spraying, flooding or dipping. This can be done using of overpressure or underpressure (e.g. vacuum). Many methods are established for applying layers to a body, including manual and mechanical (automated) methods.

In a preferred variant, the composite molded part core and/or the composite molded part shell is subjected to a further processing step. This processing step is in particular a mechanical processing step. This mechanical processing is preferably selected from a group that includes smoothing, grinding, brushing and dust removal. This can, for example, produce a smoother and/or easier to coat surface.

The mechanical processing can be carried out on the composite molded part core, for example immediately after the composite molded part core production and/or before and after the application of a first or further coating, for example the composite molded part shell.

In addition, further mechanical processing can be provided, which is preferably selected from a group that includes milling, drilling, polishing and deburring. This step can serve in particular to provide the molded part with a desired functionality. This can be done, for example, by attaching attachments to the molded part, with an attachment preferably being selected from a group that includes a faucet, a drain strainer, a waste water connection, a control element (for example for controlling the drain), a soap or detergent dispenser and a storage element. It is also conceivable that sensors are inserted or attached which record certain physical properties, e.g. the temperature, or that operating elements are attached, e.g. with a touch function for operation.

This further processing step can be carried out before, during or after the application of the layers described above or of a composite molded part shell.

Preferably, the particulate (granular) material used to produce the composite molded part core has a density of < 5 kg/l, preferably < 4 kg/l, most preferably < 3 kg/l. This has the advantage that the composite molded part core or the composite molded part containing it can be made comparatively light, which reduces transport costs and improves handling.

In order to keep the composite molded part as light as possible and thus transportable and handleable, the particulate (granular) material used to produce the composite molded part core preferably has a bulk density of < 2.5 kg/l, preferably < 2 kg/l, preferably < 1.5 kg/l, more preferably < 1 kg/l, particularly preferably < 0.8 kg/l.

Alternatively, the mass of a composite molded part can be reduced by adding fiber materials to the composite molded part core during production, which leads to an increase in mechanical strength. This allows the wall thickness to be reduced, which ultimately also reduces the weight. Such fibers can be organic or inorganic, mineral, amorphous, synthetic or bio-based.

The binder of the composite molded part core and/or the composite molded part shell preferably has (optionally independently of one another) a density ≥ 0.6 kg/l, preferably ≥ 0.9 kg/l, preferably ≥ 1 kg/l, preferably ≥ 1.1 kg/l, preferably ≥ 1.2 kg/l, and additionally or alternatively ≤ 1.7 kg/l, preferably ≤ 1.6 kg/l, preferably ≤ 1.5 kg/l, preferably ≤ 1.4 kg/l, preferably ≤ 1.3 kg/l, preferably ≤ 1.2 kg/l, preferably ≤ 1.1 kg/l.

In a preferred embodiment, the composite molded part (in its entirety) has a mass fraction of the particulate (granular) material used to produce the molded part core of ≥ 70%, preferably ≥ 75%, particularly preferably ≥ 80%, preferably ≥ 85%, most preferably ≥ 90% and additionally or alternatively ≤ 99%, preferably ≤ 98%, preferably ≤ 97%, preferably ≤ 96%, preferably ≤ 95%. A weight fraction of the particulate material in this range has proven to be advantageous, since the proportion of the cost-intensive binder can be minimized, but at the same time sufficient strength and cross-linking can be ensured by the binder.

An embodiment of the composite molded part core has proven to be particularly preferred in which a value which corresponds to one hundred times the quotient of the binder content in percent by mass and the theoretical specific surface area in cm ² /g (BET) of the particulate material is small less than or equal to 5, preferably ≤ 4.5, further preferably ≤ 4, more preferably ≤ 3.5 and particularly preferably ≤ 3. Surprisingly, a composite molded part core with such a value has excellent strength while still having a low binder content. This is advantageous both in terms of production costs and in terms of handling and use in practice.

Preferably, the composite molded part core and/or the composite molded part shell is impregnated at least in sections. The composite molded part shell can also be formed by the impregnate. The impregnate is preferably a polymer, for example a resin, preferably an epoxy resin, PU resin, acrylic resin, most preferably an epoxy resin. If the impregnate forms the composite molded part shell, it is conceivable that it also penetrates at least partially into pores of the composite molded part core. This penetration has the advantage that in addition to the adhesion to the surface of the composite molded part core, a mechanical bond in the sense of interlocking and/or anchoring of the composite molded part shell in the pores of the composite molded part core also occurs. It has surprisingly been shown that the hardness and/or breaking strength of a composite molded part core and/or a composite molded part shell is significantly increased by impregnation compared to non-impregnated composite molded parts.

In particular, it is preferred that the composite molded part core is impregnated at least in sections and/or that a composite molded part shell is formed by an impregnate that penetrates at least in sections into the composite molded part core. The impregnate preferably comprises a curable polymer, for example a resin. An embodiment in which the curable polymer is a PU resin, acrylic resin and very particularly preferably an epoxy resin has proven to be particularly advantageous. Epoxy resins can penetrate particularly well into the pores of the composite molded part core and cure there. In doing so, they stabilize the composite molded part core. Preferably, portions of the curable polymer remaining outside the composite molded part core form parts of the composite molded part shell. This is particularly advantageous because the curable polymer penetrating into the pores of the composite molded part core not only stabilizes the composite molded part core, but also creates a mechanical bond in the sense of interlocking and/or anchoring the composite molded part shell in the pores of the composite molded part core.

• - Bereitstellen einer Zusammensetzung umfassend ein partikuläres Material und ≤ 15 Masseprozent eines Bindemittels bezogen auf die Gesamtmasse der Zusammensetzung,
• - Herstellen eines geformten Verbundwerkstoffformteilkern durch zumindest teilweises Aushärten des Bindemittels,
• - Erzeugen einer Verbundwerkstoffformteilhülle, welche im Verbundwerkstoff zumindest eine Oberfläche des Verbundwerkstoffformteilkerns abschnittsweise überdeckt.

Furthermore, the invention is directed to a method for producing a composite molded part,
comprehensive the steps:

• - Providing a composition comprising a particulate material and ≤ 15% by weight of a binder based on the total mass of the composition,
• - producing a shaped composite molded part core by at least partially curing the binder,
• - Creating a composite molded part shell which partially covers at least one surface of the composite molded part core in the composite material.

This process makes it particularly easy to produce a composite molded part as described above with a composite molded part core and a composite molded part shell.

Preferably, a composition is provided which contains the particulate material and less than 15% by mass, preferably ≤ 12% by mass, preferably ≤ 10% by mass, more preferably ≤ 8% by mass, most preferably ≤ 5% by mass of the binder based on the total mass of the composition. By reducing the proportion of the comparatively expensive binder, the costs of a composite molded part core made from this composition can be significantly reduced.

It should be noted that the steps of producing the composite molded part core and producing a composite molded part shell do not have to be carried out in the order given above. It is also conceivable that the composite molded part shell is produced first, for example by spraying a composite molded part shell raw material composition into a negative mold, into which - if necessary after formation (for example curing) of the composite molded part shell - the composition provided is introduced to form the composite molded part core.

Alternatively, in a process variant, it is preferred that the composite molded part core is first produced and that this is covered at least in sections with the composite molded part shell in a subsequent process step. This in turn can be provided with one or more additional thin cover layers

In all cases, it is possible and preferred in some process variants that the step of producing the composite molded part shell takes place at a time and/or location apart from the step of producing the composite molded part core. It is conceivable, for example, that the composite molded part core is manufactured at one location and later adapted at another location by the same or another company in a customer-specific manner by applying the desired composite molded part shell and/or cover layer.

Preferably, a composition for producing the composite molded part shell is selected such that a mass fraction of all binding agents used to produce the composite molded part is ≤ 25 mass percent, preferably ≤ 22 mass percent, preferably ≤ 20 mass percent, more preferably ≤ 18 mass percent, most preferably ≤ 15 mass percent. As a result, a composite molded part can be produced and offered particularly cost-effectively.

• - Beaufschlagung mit einer Temperatur ≥ 25°C, weiter bevorzugt ≥ 30°C, mehr bevorzugt ≥ 40°C, noch mehr bevorzugt ≥ 50°C, meist bevorzugt ≥ 60°C, und/oder
• - Beaufschlagung mit einem Reagenz, vorzugsweise Begasung, bevorzugt mit einem Amin, und/oder
• - Beaufschlagung mit elektromagnetischer Strahlung, bevorzugt UV-Beaufschlagung, Lichtbeaufschlagung und/oder IR-Beaufschlagung und/oder
• - durch Zusatz eines Katalysators

erfolgt. Es hat sich gezeigt, dass dadurch eine besondere Festigkeit und/oder Strapazierfähigkeit des Verbundwerkstoffformteilkerns erreicht werden kann.In a preferred process variant, it is provided that the at least partial hardening of the binder under

• - exposure to a temperature ≥ 25°C, more preferably ≥ 30°C, more preferably ≥ 40°C, even more preferably ≥ 50°C, most preferably ≥ 60°C, and/or
• - Exposure to a reagent, preferably gassing, preferably with an amine, and/or
• - Exposure to electromagnetic radiation, preferably UV exposure, light exposure and/or IR exposure and/or
• - by adding a catalyst

It has been shown that this can achieve a particular strength and/or durability of the composite molded part core.

Furthermore, a method variant is preferred in which a surface of the composite molded part core and/or the composite molded part shell is processed. This is preferably processed mechanically. The processing preferably comprises at least one step which is selected from a group comprising smoothing, grinding, brushing, dust removal, milling, drilling, polishing and deburring. By means of one or more of these steps, it is easily possible to adapt the composite molded part core or the entire composite molded part comprising the composite molded part core to specific customer wishes and/or requirements.

In a preferred process variant, the composite molded part core and/or the composite molded part shell is impregnated. The impregnate is preferably a polymer, for example a resin, preferably acrylates, urethanes or epoxies, most preferably an epoxy resin. Surprisingly, it has been shown that such an impregnation can significantly increase the hardness and breaking strength of a composite molded part, or of the composite molded part core and/or the composite molded part shell. The impregnation process can be supported by external influences, for example by ultrasonic exposure or shaking.

In addition to these and other technical advantages, the novel process also leads to significant economic and ecological advantages, which is ultimately also enormously beneficial for the economic and ecological evaluation of the composite molded parts produced thereby and/or the end products containing such a composite molded part, such as sinks, washbasins, shower trays, bathtubs and worktops.

Furthermore, the object underlying the invention is achieved by a method for recycling a composite molded part core and/or a composite molded part produced according to the method described above. This method is characterized in that a binding ability of the at least partially cured binder is reduced in such a way that the bond between two adjacent particles of the particulate material is eliminated. If this bond between several, preferably (almost) all particles of the particulate material is eliminated, the composite material disintegrates. molded part core and/or the composite molded part. The individual components can be separated from one another and sent for further recycling separately. In particular, this makes it possible to recover the particulate material and, for example, use it again as particulate material in a composite molded part core.

A process variant has proven to be particularly preferred in which the binding ability of the at least partially cured binder is reduced by the application of pressure and/or shear force. The pressure and/or shear force can be introduced, for example, by means of a mixer or stirrer.

Alternatively or in addition to this, a reduction in the binding capacity of the at least partially cured binding agent by exposure to temperature is conceivable and preferred in some variants. When exposed to temperature, the at least partially cured binding agent can denature and/or decompose, thereby reducing its ability to bind the particles of the particulate material.

The invention is also directed to a composite molded part which comprises a composite molded part core as described above. Such a composite molded part has proven to be particularly advantageous if it is intended and suitable for use in the kitchen and/or sanitary area. In particular, it is preferred that the composite molded part is selected from a group which includes wash basins, sinks, shower trays, bathtubs, bidets, toilets, worktops, furniture or furniture parts, floor coverings, wall coverings and tiles.

In a preferred embodiment, such a composite molded part has a mass fraction of all binding agents used to produce it of ≤ 25 mass percent, preferably ≤ 22 mass percent, preferably ≤ 20 mass percent, more preferably ≤ 18 mass percent, most preferably ≤ 15 mass percent. Such a small proportion of the comparatively expensive binding agent makes it possible to produce and offer such a composite molded part particularly cost-effectively.

It has been shown that, in particular by adapting the properties of a composite molded part shell, the properties of the composite molded part can be adapted in such a way that it also achieves or even exceeds the properties of the products known from the state of the art that are relevant for the respective application.

A composite molded part as described above can preferably be produced using the method described above. Accordingly, all properties resulting directly or indirectly from the method should be considered as disclosed for the composite molded part. The method is particularly suitable and/or intended for producing a composite molded part as described above.

Conversely, all described properties of the composite molded part and/or the composite molded part core, individually or in combination, should also serve to characterize the process described above in its entirety or individual raw materials or compositions used and/or the (intermediate) products obtained thereby.

Further advantages, objects and characteristics of the present invention are explained using the following examples of selected embodiments and variants.

Examples and test results

In a first series of tests, the influence of the particle size of the particulate material and the amount of binding agent on strength and processability was investigated. For this purpose, various test specimens were produced and compared with each other.

Sands with different average particle sizes were used as particulate material. The physical characteristics of these sands are shown in Table 2. Based on the average particle size of these three sands, they are designated as No. 15 (average particle size ≈ 0.15 mm (sieve analysis)), No. 19 (average particle size ≈ 0.19 mm (sieve analysis)) and No. 25 (average particle size ≈ 0.25 mm (sieve analysis)). Table 2: Physical characteristics of various sands Physical characteristics No. 15 No. 19 No. 25 Average particle size (sieve analysis) 0.146mm 0.2mm 0.242mm AFS Key Figure 91 66 57 Theoretical specific surface area 165 ^cm2 /g 117 ^cm2 /g 99 ^cm2 /g Degree of uniformity 75% 63% 88% Loss on ignition < 0.2% < 0.2% < 0.2% Start of sintering > 1550-1600 °C > 1550 °C > 1550 °C Bulk density fire dried 1.34 tons/m ³ 1.37 tons/m ³ 1.37 tons/m ³

A composition known as a cold box binder system was used as the binder. For the test series described, this includes “Askocure 388” (Part 1) and “Askocure 688” (Part 2) in a 1:1 mixing ratio as well as a catalyst “ASK 704” (amine).

To produce the compositions, the binding agent system was added to the three different sands in three different quantities: Sand No. 15 in quantities of 3 wt.%, 4 wt.% and 5 wt.%; Sand No. 19 in quantities of 2 wt.%, 3 wt.% and 4 wt.%; and Sand No. 25 in quantities of 1 wt.%, 2 wt.% and 3 wt.%. As can be seen from Table 3, these figures refer to the total mass of the mix of the components Part 1 and Part 2 (see Table 3).

The compositions were produced on the basis of 30 kg of the respective sand. The respective sand was mixed in a forced mixer for 5 minutes with the binding agent in the amount specified in Table 3. Composite molded cores, in this example bending bars in the format 22 x 22 x 160 mm, were produced from each composition using a laboratory core shooting machine (semi-automatic ramming device, PN/DIN from Morek Multiserw). The strengths of the manufactured bending bars were measured after the times specified in Table 3 using a strength testing device (universal strength testing device 0 - 6000 N/cm ² , Morek Multiserw). The results are listed in Table 3. Table 3. Testing the strengths*** of various bending bars Experiment No. Sand*-No. Mass fraction Mass fraction BET** in cm ² /g Strength in N/cm ² (based on PN 83 H-11073 / EN) immediately 0.5 hours 1 hour 2 hours 24 hours Askocure 388 in % Askocure 688 in % Total binder content (Ma-%) after removal from core shooter 1 15 1.5 1.5 3 165 421 485 587 600 697 2 15 2.0 2.0 4 165 584 770 885 860 967 3 15 2.5 2.5 5 165 630 720 871 941 1010 4 19 1.0 1.0 2 117 305 410 441 440 487 5 19 1.5 1.5 3 117 310 408 421 442 463 6 19 2.0 2.0 4 117 418 510 520 615 728 7 25 0.5 0.5 1 99 130 217 230 211 217 8 25 1.0 1.0 2 99 310 410 418 457 488 9 25 1.5 1.5 3 99 380 550 564 604 640 10 Mix**** 1.0 1.0 2 132 440 493 595 620 723 11 Mix**** 2.0 2.0 4 132 610 780 905 915 942 * = based on the d ₅₀ value, which is approx. 150, 190 and 250 µm ** = BET = theoretical. specific surface in cm ² /g *** = Strengths in N/cm ² **** = Mix: No.15 and No.25 were mixed 1:1

As can be seen from Table 3, the measured strengths of almost every test specimen increase with increasing maturation time, i.e. the time that has passed until the strength is measured.

For test specimens No. 1 - 3, each containing the same sand (No. 15), the measured strengths increase significantly with increasing binder content.

For test specimens No. 4 - 6 (with sand No. 19), those test specimens with the highest binder content also show the highest strengths.

Also for test specimens No. 7 - 9, which each contain sand No. 25, the measured strength increases significantly with increasing binder content.

For test specimens No. 10 and No. 11, which contain the (bimodal) mixture of sands No. 15 and No. 25, a further increase in strength was measured. For example, the strength measured for test specimen 10 is greater than for test specimen No. 1 at each of the measured times after removal from the core shooter, despite the reduced binder content compared to test specimen 1. Even compared to test specimen No. 8, which has an identical binder content but only contains a single sand, namely sand No. 25, a higher strength was measured in each test than for test specimen No. 8 at the same time after removal from the core shooter.

With the same binder content of 3% by mass, clear differences in strength can be measured between test specimens 1, 5 and 9, which contain only one of the three different sands. It can be deduced from these measurements that the average particle size of the particulate material has a noticeable influence on the strength of the test specimens made from it. It is noteworthy that the test specimens made with sand No. 19, which has an average particle size between the other two sands No. 15 and No. 25, have the lowest strengths in comparison.

From these results it can be deduced that the manufacturing process and the properties of composite molded part cores can be specifically controlled via the average particle size, the grain distribution and the binder content. It is to be expected that this will also result in differences in the post-processing properties and/or the properties of a composite molded part produced from it, such as porosity, absorbency and smoothness.

In another series of tests, the influence of the average particle size and the binder content on the strength and processability of test specimens was determined. The three sands No. 15, No. 19 and No. 25 described above were also used for this purpose. However, an inorganic binder, namely ASK, Inotec EP 4158 (liquid, water glass preparation), was used as the binder and ASK, Inotec TC 4500 (powder) was used as the promoter (hardener). The test specimens were produced using the hotbox process, with a Loramendi, MDR-0.5, 2014, being used as the core shooter. The compositions were prepared manually using a Kenwood mixer based on 1 kg of the respective sand. The sand was added and the promoter was mixed in. The binder was then added.

The mold temperature was 150 °C and the shooting pressure was 5 bar. The gassing was carried out with hot gas at a temperature of 200 °C at a hot gas pressure of 3 bar over a hot gas purging time of 15 s.

As shown in Table 4, 8 different samples A - H were prepared. Samples A - C are based on sand No. 19, samples D and E on sand No. 25 and samples F and G on sand No. 15. In addition, for sample H, a bimodal mixture of sands No. 15 and No. 25 in a mass ratio of 1:1 was used.

Compositions with a low water glass content of 3 mass percent and a low additive content of 2.4 mass percent and a high water glass content of 5 mass percent and a high additive content of 4 mass percent were prepared from all three individual sands. Based on sand No. 19, a composition with a medium water glass content of 4 mass percent and a medium additive content of 3.2 mass percent was also prepared. For sample H, based on the bimodal mixture of sands No. 15 and No. 25, only the low water glass content of 3 mass percent and low additive content of 2.4 mass percent were used to produce the composition. The compositions of samples A - H can be found in Table 3. Table 3: Compositions of samples A - H Sample labeling Sand No. Water glass content in Ma-% Additive content in Ma-% A 19 3.0 2.4 B 19 4.0 3.2 C 19 5.0 4.0 D 25 3.0 2.4 E 25 5.0 4.0 F 15 3.0 2.4 G 15 5.0 4.0 H Mix* 3.0 2.4 *= Mix: Sand No.15 and No.25 were mixed in a mass ratio of 1:1

Strength measurements were carried out on the test specimens obtained from this. The determination was carried out using three-point bending on a ZwickRoell tension-compression testing machine with a support distance of 150 mm. First, a force of 20 N was applied and then the loading body was moved at a speed of 1 mm/min until it broke. The maximum force determined in triplicate is shown in Table 5. Table 5: Results of maximum force Water glass content in Ma-% Sand No. 19 Sand No. 25 Sand No. 15 Mix of sand No. 15 and No. 25 sample Max power sample Max power sample Max power sample Max power 3.0 A1 189 D1 182 F1 199 H1 220 A2 183 D2 164 F2 205 H2 225 A3 189 D3 151 F3 221 H3 235 4.0 B1 230 E1 235 G1 320 B2 239 E2 228 G2 284 B3 232 E3 220 G3 280 5.0 C1 251 C2 255 C3 245

As can be seen from Table 5, for all particle sizes of the sands used, the maximum force that can be applied to the test specimen until it breaks increases with increasing mass fraction of the binder used (water glass). The (bimodal) mixture of sands No. 15 and No. 25 has a higher maximum force than any of the measured test specimens based on a single sand with the same amount of binder (3 mass % water glass).

The table also shows that, with the same binder content, the measured strengths of the test specimens based on sands of different average particle sizes differ noticeably. It can therefore be concluded that the average particle size has a demonstrable influence on the strength, or the maximum force. For the only three average particle sizes measured, there is a tendency that a smaller average particle size leads to an increased strength of the test specimen.

Furthermore, gas permeability measurements were carried out on the test specimens A - H described above. The test setup used for this purpose was developed by the Technical University of Munich. It is available in 2 shown schematically.

The gas permeability was measured by measuring the volume flow through the sample with a pressure ramp in the test chamber from 0 to 440 mbar at 440 mbar/min. The results are shown in Table 6. Table 6: Results of the gas permeability test, details of the gas permeability as volume flow through the sample in m/s sample Pressure difference [Pa/m*10 ⁵ ] 1 2 3 4 5 6 A 0.15 0.31 0.44 0.57 0.69 0.81 B 0.15 0.30 0.43 0.56 0.68 0.80 C 0.12 0.25 0.36 0.47 0.57 0.67 D 0.23 0.43 0.60 0.76 0.88 1.01 E 0.23 0.42 0.59 0.75 0.88 1.00 F 0.1 0.20 0.30 0.39 0.48 0.56 G 0.09 0.18 0.27 0.36 0.44 0.53 H 0.07 0.15 0.24 0.32 0.40 0.49

As can be seen from Table 6, it can be seen that the gas permeability tends to be higher with coarser grain sizes of the particulate material. However, the influence of the binder content on the gas permeability is small or almost non-existent. The bimodal mixture (H) has a lower gas permeability than the test specimens based on sand No. 15 (samples F and G). Compared to test specimens based on sand No. 25 (samples D and E), the gas permeability is even significantly lower.

The influence of impregnation on the breaking strength of a selection of test specimens was examined. The test specimens for the investigation of this type of post-treatment were produced on the basis of a sand designated H33 with the grain size distribution given in Table 7 (determined by sieve analysis). Table 7: Grain size distribution of sand “H33” % by weight Grain size [mm] 0 > 1,000 0 0.710 0 0.500 6 0.355 46 0.250 39 0.180 8 0.125 1 < 0.125

Two different binder systems were used to produce the test specimens.

For test specimens of the first type, referred to here as "BAF", a two-component binder from Hüttenes Albertus was used as a binder, namely Biocure 7241 "P1" and Biocure 6324 "P2". For a batch of 3 kg, 24 g of each of these components P1 and P2 were used, which corresponds to 0.8 wt%. To do this, component P1 was first added to the sand and mixed in a laboratory concrete mixer with a volume of 5 liters for 2 minutes. P2 was then added and mixed again for 2 minutes. The pot life of the sand / binder mixture obtained in this way was at least 20 minutes.

Further processing into test specimens was carried out using a laboratory shooting machine, Morek Multiserw, PL, with a shooting time of 3 s, a delay of 3 s and subsequent amine application. The amount of amine was 0.5 ml. After the amine application, the specimen was rinsed for 30 s (bubble time after amine 30 s).

For test specimens of the second type, referred to here as "ASK", the same sand H33 was used, but a two-component binder from ASK, namely Askocure 688 "P1" and Askocure 388 "P2", was used. Analogous to the test specimens of the first type, 0.8 wt.% of the binder components were added to the sand. This was also done in two stages, namely in such a way that first the component P1 was mixed with the sand in a laboratory concrete mixer with a volume of 5 liters for 2 minutes. Then P2 was added and mixed again for 2 minutes. The test specimens were formed using a semi-automatic laboratory shooting machine.

Fracture tests and impregnation tests were then carried out on the test specimens of both types obtained in this way. The (fracture) strength of the (impregnated) test specimens was determined on a ZwickRoell tensile-compression testing machine as a three-point bend. The support distance was 150 mm. A test was carried out up to 20 N and then the loading body was moved until it broke at a travel speed of 1 mm/min.

Some of the test specimens of type “ASK” and type “BAF” obtained in this way were impregnated with a 2-component epoxy resin (EP resin). The EP resin components were CeTePox 255-3R (resin) and CeTePox 1502H (hardener). These were used in a mass ratio of 100:55.

For impregnation, the EP resin mixture obtained in this way was placed at room temperature and the test specimens were impregnated with it by completely immersing them for a period of 9 minutes. For the impregnation of some test specimens, the impregnation was additionally supported by a) exposure to ultrasound b) treatment on a vibrating table. After the immersion process was completed, the impregnated test specimens were cured for 12 hours at 65 °C.

The (breaking) strength of the (impregnated) test specimens was then measured on the ZwickRoell tensile-compression testing machine as a three-point bend as described above. The measured strengths of the various test specimens are given in Table 8. Table 8: (Breaking) strength of the (impregnated) test specimens Binders, impregnation Polymer content after impregnation* [Ma-%] Degree of filler, here quartz, [Ma-%] Strength [N] ASK, not impregnated 1.6 98.4 204 ASK, 2K-EP, without additional treatment 25.5 74.5 2292 ASK, 2K-EP, with ultrasonic treatment 26.2 73.9 2168 ASK, 2K-EP, with vibrating table treatment 25.1 74.9 2289 BAF, not impregnated 1.6 98.4 179 BAF, 2K-EP, without additional treatment 26.3 73.7 2486 BAF, 2K-EP, with ultrasonic treatment 27.4 72.6 2454 BAF, 2K-EP, with vibrating table treatment 27.1 72.9 2475 *) Polymer content based on the mass of the test specimen after impregnation

As can be seen from Table 8, the strength increases significantly through impregnation. The strength measured after impregnation is slightly higher for the “BAF” type test specimens than for the “ASK” type. Mechanical support during impregnation through ultrasound exposure or vibrating table treatment does not have a major positive influence.

For comparison, test specimens measuring 22 x 22 x 160 mm were cut from PMMA and polyester-bonded composite kitchen sinks. In addition, composite test bars measuring 22 x 22 x 160 mm were cast from polyester with quartz as a filler with various quartz contents. The test specimens were tested for strength as described above. The measured strengths of the various test specimens are shown in Table 9. Table 9: Strengths of the test specimens (comparison) Manufacturer binder Degree of filler, here quartz [Ma-%] type Strength N p. PMMA 73 cut 1060 E. PMMA 70 cut 632 D. polyester 73 cut 1035 D. polyester 73 cut 971 D. polyester 65 cast 1683 D. polyester 70 cast 1663 D. polyester 73 cast 1753

A comparison of the strengths of the test specimens listed in Table 9 with those in Table 8 shows that the measured strengths of the test specimens without additional impregnation are lower than those of the comparison test specimens listed in Table 9. However, if the test specimens are impregnated, their strength increases significantly in all cases and significantly exceeds the measured strengths of all comparison test specimens.

In order to investigate the effect of the impregnation in more detail, the test specimens of the "BAF" type and the "ASK" type described above were each impregnated for different time intervals. The EP resin components were identical to the impregnates described above, namely CeTePox 255-3R (resin) and CeTePox 1502H (hardener) in a mass ratio of 100:55. This EP resin mixture was introduced at room temperature and the test specimens were completely immersed in the resin mixture. In no case was mechanical support provided by ultrasonic exposure or vibrating table treatment.

The duration of the impregnation process was significantly reduced and was 1 s, 5 s or 15 s in this series of tests. Due to the shortened impregnation time, less impregnate was able to penetrate into the pores of the test specimens. The filling level resulting from the sum of binder and impregnate is therefore significantly lower than the filling level given in Table 8 for impregnated test specimens, but increases with longer impregnation time. After the test specimens were removed from the impregnating mass, the impregnated samples were cured for 12 hours at 65 °C, analogous to the above series of tests.

Unlike the “BAF” type test specimens, the “ASK” type test specimens were impregnated with an impregnating compound that contained a pigment in addition to the EP resin components. In the test series described, a black pigment (soot) was used and added to the impregnating compound in a mass fraction of 10%. The strengths determined for the test specimens impregnated in this way over shorter periods are shown in Table 10. Table 10: (Fracture) strengths of the (impregnated) test specimens binder Polymer content after impregnation*, [Ma-%] Degree of filler, here quartz, [Ma-%] Strength N BAF, not impregnated 1.6 98.4 201 BAF, 2K-EP, impregnated for 1 s 9.7 90.3 859 BAF, 2K-EP, impregnated for 5 s 13.6 86.4 1273 BAF, 2K-EP, impregnated for 15 s 13.1 86.9 1183 ASL, Blind 1.6 98.4 223 ASK, 2K-EP, impregnated for 1 s, black 9.3 90.7 861 ASK, 2K-EP, impregnated for 5 s, black 9.7 90.3 1070 ASK, 2K-EP, impregnated for 15 s, black 11.5 88.5 1153 *) Polymer content based on the mass of the test specimen after impregnation

Table 10 shows that the strength increases significantly with the impregnation time and thus with the filling level (of the EP resin).

The degree of blackening of the test specimen surface increases with the duration of the impregnation steps. A deep black, opaque surface is achieved after just 15 seconds of impregnation.

Furthermore, the influence of the binder content used on the manufacturing process and on the strength was investigated using various test specimens. In a similar way to the test specimens of type “BAF” described above, the sand H33 described above and the binder from Hüttenes Albertus, Biocure 7241 P1 and Biocure 6324 P2 were used. First, P1 was added to 3 kg of sand in a laboratory concrete mixer with a volume of 5 litres and mixed for 2 minutes. Then P2 was added and mixed for a further 2 minutes.

In contrast to the test specimens described above, however, the mass of the binder added was changed and set to a total of (P1 + P2) 2.0 wt. %, 4.0 wt. %, 6.0 wt. %, or 8.0 wt. % for the various test specimens. The pot life of the resulting compositions was at least 20 minutes in each case.

A laboratory shooting machine from Morek Multiserw, PL was used to produce the test specimens. The shooting time was 3 s and the delay was also 3 s. This was followed by an amine application, with the amine quantity being 1.5 ml. After the amine application, the specimen was rinsed for 30 s (bubble time after amine 30 s). The strengths measured on these test specimens (analogous to the measurement described above) are shown in Table 11. Table 11: Strengths of test specimens (type "BAF") with various binder proportions Binder and target proportion Polymer content of the test specimen* [Ma-%] Degree of filler, here quartz, [Ma-%] Strength in N BAF, 2 Ma-% 2.0 98.0 223 BAF, 4 Ma-% 3.9 96.1 441 BAF, 6 Ma-% 5.9 94.1 595 BAF, 8 Ma-% 7.2 92.8 706 *) Polymer content based on the mass of the test specimen

The trend is clearly visible that the strength increases with increasing proportion of polymer relative to the mass of the test specimen.

Analogous test specimens were also produced with a different binder, namely a 2-component epoxy resin. Test specimens of this type are referred to below as "EP" or "EP type". The epoxy resin was produced from 100 parts by mass of CeTePox 255-3R (resin) and 55 parts by mass of CeTePox 1502H (hardener). After these components had been thoroughly mixed, the resulting mixture was added to 3 kg of sand H33 in a laboratory concrete mixer with a volume of 5 liters and mixed for 2 minutes.

For the various test specimens, 2.0 wt.%, 4.0 wt.%, 6.0 wt.%, or 8.0 wt.% of the binder (in this case the mixture of resin and hardener) were also used. The test specimens were also produced using a laboratory shooting machine from Morek Multiserw, PL with a shooting time of 3 s and a delay of 3 s. Curing took place at a tool temperature of 70 °C for a period of 7.5 minutes. The strengths determined on the test specimens produced in this way are shown in Table 12. The resin and hardener quantities given in this table refer to the batch size of 3 kg sand described above. Table 12: Strengths of test specimens with various epoxy resin binder proportions Binder, target content Resin quantity / g Hardener quantity / g Polymer content of the test specimen* [Ma-%] Degree of filler, here quartz, [Ma-%] Strength N EP, 2 wt% 38.7 21.3 2.0 98.0 423 EP, 4 wt% 77.4 42.6 4.3 95.7 677 EP, 6 Ma-% 116.1 63.9 6.3 93.7 805 EP, 8 Ma-% 154.8 85.2 7.2 91.8 973 *) Polymer content based on the mass of the test specimen

Even when using an epoxy resin as a binder, the strength increases with increasing binder content - as can be seen in Table 12. The test specimens with EP resin as a binder show a higher strength than test specimens of the "BAF" type with the same binder content.

Other EP-type test specimens were also produced based on a different sand than the H33 sand used above. These test specimens were produced in a similar way to the process described above. The only difference is that a mixture of two black sands was used instead of the H33 sand. The sands used are called a) Mix 29/2013 and b) Mix 10/2022. These materials are pigmented sands with a grain size (sieve analysis) of 0.09 - 0.5 mm and an average grain size d ₅₀ = 0.25 mm, with the pigment fixed to the sand with a binder. These sands are used to manufacture acrylic and/or polyester-based kitchen sinks according to the state of the art, usually with a filling level of 65-70 mass% sand based on the total mass of the sink. Uniformly colored, deep black test specimens were obtained. The results of the strength test are shown in Table 13. Table 13: Strengths of test specimens with coloured sand mixtures Binder, target quantity sand Polymer content of the test specimen* [Ma-%] Degree of filler, here quartz, [Ma-%] Strength N EP, 2 wt%, Mix 29/2013 2.1 97.9 673 EP, 4 wt%, Mix 29/2013 4.2 95.8 822 EP, 2 wt%, 10/2022 2.0 98.0 651 EP, 4 wt%, 10/2022 4.2 95.8 805 *) Polymer content based on the mass of the test specimen

As can be seen from Table 13, the strength increases with the filling level, regardless of the sand used.

In a further series of tests, test specimens were examined that contained Croning sand “LH” as a particulate material. This is a resin-coated sand (phenolic resin-coated) with a grain size d ₅₀ (sieve analysis) of 250 µm. To produce the test specimens, the EP resin was used as a binder with a mass fraction of 2.0 wt. %, 2.5 wt. % or 3.0 wt. % as in the above tests. The mixture was molded into the mold by shooting as described above, with preheating to 120°C and the mold temperature being 300°C. The strength measurements were carried out analogously to the above and the strengths shown in Table 14 were determined. Table 14: Strengths of test specimens with Croning sand “LH” 2 Ma-%* 2.5 Ma-%* 3.0 Ma-%* Newton 653 921 1210 *) Polymer content based on the mass of the test specimen

Further advantages, objects and characteristics of the present invention will become apparent from the following description of the accompanying figures.

• 1 eine beispielhafte Geometrie eines Verbundwerkstoffformteils,
• 2 eine Vorrichtung zur Messung der Porosität eines Prüfkörpers
• 3a - 3e Teile einer Form, mit der Verbundwerkstoffformteilkerne hergestellt werden,
• 4a - 4b Ausschnitte eines Profils eines Verbundwerkstoffformteilkerns,
• 5a - 5b Ausschnitte eines Profils eines Verbundwerkstoffformteilkerns,
• 6a - 6d Beispielhafte Verbundwerkstoffformteilkerne
• 7 ein Beispiel eines mit einem Gießereialtstand hergestellten Verbundwerkstoffformteilkerns,
• 8a - 8b Beispiele einer Imprägnierung und Beschichtung, und
• 9a - 9b ein Beispiel eines Verbundwerkstoffformteils nach Imprägnierung und Beschichtung.

In the figures show:

• 1 an example geometry of a composite molded part,
• 2 a device for measuring the porosity of a test specimen
• 3a - 3e Parts of a mold used to produce composite mold cores,
• 4a - 4b Sections of a profile of a composite molded part core,
• 5a - 5b Sections of a profile of a composite molded part core,
• 6a - 6d Example composite molded cores
• 7 an example of a composite molded part core produced using a foundry-old stand,
• 8a - 8b Examples of impregnation and coating, and
• 9a - 9b an example of a composite molded part after impregnation and coating.

1 shows an example of a geometry of a composite molded part. In 1 a kitchen sink 1 is shown. It comprises a (at least largely flat) storage area 2 in the area shown on the left and a (washing) basin 3 in the area on the right. An opening 4 is arranged in this basin, which is usually designed as a closable drain 4 when in use.

In order to allow the drainage of liquid between objects arranged on the storage surface 2 into the basin 3, even underneath the respective object, the storage surface 2 has profiles 5. These can be designed as elevations or depressions. In the example shown, the profiles 5 are designed as elevations. In this variant, it is not absolutely necessary for the profiles 5 extend to the edge of the basin 3, as would be necessary for channels that would have to have an opening in the area of the basin 3 to allow liquid to drain into the basin. The elevations 5 ensure that at least in some areas a gap is formed between the storage surface 2 and an object arranged on it. This gap allows liquid to drain into the basin 3 and thus also into the drain 4.

The reference number 6 indicates an opening through which, for example, a liquid line can be guided. Such a liquid line is usually designed with a valve and usually also a mixing unit so that the liquid flow can be regulated and, if necessary, several liquids (usually hot and cold water) can be mixed together. Such a liquid line is therefore usually designed as a faucet and is firmly connected to the kitchen sink 1. The connection is usually realized by a clamp connection.

It is self-evident that the 1 is just an example variant of a composite molded part, shown here using the example of a kitchen sink. A kitchen sink can, for example, have two or more sink inserts or even additional storage areas. The design here (and elsewhere) is only an example. The same applies in principle to the variety of shapes and designs for washbasins, shower trays or bathtubs.

2 shows the device used to measure the porosity of a test specimen. This test device is a setup that is used at the Technical University of Munich to carry out gas permeability tests.

The sample identified by reference number 42 is located in a crucible 41, which is closed by an upper and a lower end piece 40. The crucible 41 can be tempered by a tempering system 30. The crucible 41 with the sample 42 is located in a housing 39, the internal temperature of which can be measured with a temperature sensor 34. The temperature of the crucible 41 itself can be determined without contact using a pyrometer 32.

The gas permeability is measured by feeding a gas, in this case the inert gas argon, from a pressure reservoir 31 into the housing interior 39. On the way between the pressure reservoir 31 and the housing interior 39, the gas passes a control device 33, by means of which the flow and pressure of the gas can be regulated. The gas flowing into the housing interior 39 is applied to the test body 42. The gas passing through the test body 42 can flow out through an exhaust line 36 in the direction of the arrow P. In doing so, it passes a flow measuring device 35, which provides data that is characteristic of the gas permeability of the sample.

The exhaust pipe 36 preferably opens into a container filled with water 37. The depth to which the end piece of the exhaust pipe 36 is immersed in the water 37 allows the counterpressure acting on the exhaust gas flow to be set very precisely. In order to ensure consistent conditions in this regard, the container filled with water 37 is preferably arranged on an analytical balance 38. This makes it possible to precisely set and document the water quantities and thus the counterpressure acting on the exhaust gas flow.

The 3a to 3e show parts of a mold used to produce composite mold cores. 3e shows the individual parts shown in the previous figures in an arrangement as they are placed on top of each other to form a mold. As can be seen in particular in 3a As can be seen, the shape has openings to allow displaced gas to escape.

At the 3b In the exposed contact surfaces between two adjacent molded parts, channels can be seen through which a tempering medium can flow, by means of which the molded parts can be set to a desired temperature.

With the 3a to 3e Composite molded part cores 100 were produced in the form shown and used for further testing and optical evaluation. The 3a to 3e The shape shown was chosen because it is similar to a mold used to make a kitchen sink or wash basin. However, it has fine contours all around, so that the formation of these contours allows a very accurate assessment of the quality of the molding process.

Compositions as described above in Table 3 were used for the tests. Askocure 388 and Askocure 688 were used as binders. An amine (ASK 704) served as a catalyst. Approximately 6 kg of the respective composition were used for each of the test specimens produced in this way.

The composite mold cores 100 obtained were subjected to a visual inspection. As indicated above, the formation of the profiles in the peripheral area of the mold was of particular importance. Some sections of the obtained profiles are shown in the 4a to 6b shown. The 4a The profile shown is an example of a composite molded part core in which the molding has not been completed. In the area of a projection 60, defects 62 are clearly visible.

The situation is different with the 4b The section of the profile shown in 4b In the composite molded part core shown, the profile is completely formed and the projection 60 also has no defects.

For a better overview, such a situation is also included in the 5a and 5b The profiling is completely formed in the composite molded part core 100 marked with the number 8. No defects are visible. In contrast, in the case of the 5b In the composite molded part core 100 shown and marked with the number 9, a defect 62 can be seen in the profile marked with reference number 60.

A summary of the results of the optical evaluation is shown in Table 15 below. It is noteworthy that the molding was not complete for the composite molding cores with numbers 3, 6 and 9. These are the composite molding cores with the highest binder content for their group (with an identical average particle size) of 5 mass percent, 4 mass percent and 3 mass percent respectively. Table 15: Result of the optical evaluation of various moldings No. Sand* 388 688 Total binder [Ma-%] BET* Key figure: BM/BETx100 Forming 1 15 1.5 1.5 3 165 1.82 full 2 15 2.0 2.0 4 165 2.42 full 3 15 2.5 2.5 5 165 3.03 Not full 4 19 1.0 1.0 2 117 1.71 full 5 19 1.5 1.5 3 117 2.56 Full 6 19 2.0 2.0 4 117 3.42 Not full 7 25 0.5 0.5 1 99 1.01 Full 8 25 1.0 1.0 2 99 2.02 Full 9 25 1.5 1.5 3 99 3.03 Not full *BET = theoretical. specific surface in cm ² /g

Surprisingly, it was found that there is a relationship between the forming behavior and the 100-fold ratio of the binder content in mass percent (“BM”) to the BET value. Complete forming could be achieved if this index did not exceed the value 3. However, if the index was above 3, the forming of the test specimens was not complete.

Further composite molding cores were manufactured on the basis of a sand designated as sand no. 19 with the binder system also used for the composite molding cores described above, comprising the components Askocure 388 (P1), Askocure 688 (P2) in a mass ratio of 1:1 and the amine ASK 704. The mass fractions of the binder were 0.8%, 1.0% or 1.2%, which results in a BM/BETx100 index of significantly less than 3. Sand no. 19 has the properties listed in Table 16. Table 16: Properties of sand No. 19 Physical characteristics | Physical characteristics Medium grain size 0.2mm AFS number | AFS number 66 Theoretical specific surface area | Theoretic specific 117 ^cm2 /g Uniformity ratio 63% Loss of ignition | Loss on ignition < 0.2% Start of sintering | Sintering point > 1550 °C Bulk density fire dried | Bulk density fire dried 1.37 tons/m ³

The preparation of the compositions and the manufacture of the composite molding cores was carried out according to the same procedure as in connection with the 4a and 5b described composite molded part cores. The mold used was also identical.

As can be seen from Table 17, complete molding can be achieved for all composite molding cores produced in this way. Examples of composite molding cores from this test series are shown in the 6a - 6d As can be seen from these, complete molding was achieved for all composite mold cores of this type. 6a a representation of a composite molded part core, which was manufactured with a binder content of 1.2 mass percent, whereas 6b - 6c Representations of a composite molded core for which a binder content of 1.5 mass percent was used. 6d shows a detailed section in the area of the recess. Table 17: optical evaluation of the shape and index BM/BET*100 No. Sand* 388 688 Total binder [Ma-%] BET** Key figure: BM/BET*100 Forming 4 19 0.4 0.4 0.8 117 0.68 full 5 19 0.6 0.6 1.2 117 1.03 full 6 19 0.75 0.75 1.5 117 1.28 full * = based on the d ₅₀ value, which is approx. 150, 190 and 250 µm ** = BET = theoretical. specific surface in cm ² /g

Further composite molding cores were manufactured based on other particulate materials. The binder system used for the composite molding cores described above was also used for this purpose, with the components Askocure 388 (P1), Askocure 688 (P2) in a mass ratio of 1:1 and subsequent amine application. The mass fractions of the binder were between 2 and 5 mass percent, as listed in Table 18. The binder content was chosen to be somewhat higher than for the above series of tests based on sand No. 19 due to the partially higher specific surface area and partially higher absorbency of the materials used. The BM/BETx100 index calculated as a function of the BET of the various particulate materials used was between 1.53 and 2.32. The particle sizes given in Table 18 for the various materials were determined by sieve analysis.

The foundry waste listed as No. 1 is foundry waste sand, i.e. old sand that accrues in an iron foundry. This includes both core and molding sand in a ratio of approximately 1:1. The 0.1 - 0.5 mm fraction was sieved out of this old sand and used as particulate material in the sense of this invention.

The nutshell granulate (No. 2) is a nutshell granulate available on the market, which is mainly based on hazelnut shells. This was sieved at 0.1 - 0.5 mm and this fraction was used as particulate material in the sense of this invention.

The olive stone granulate (No. 3) is also a product available on the market, which was sieved at 0.1 - 0.5 mm and this fraction was used as particulate material in the sense of this invention.

The recycled glass granulate listed as No. 4 is a white glass granulate available on the market which was sieved at 0.1 - 0.5 mm and this fraction was used as particulate material in the sense of this invention.

To produce the recyclate from PMMA kitchen sinks listed as No. 5, PMMA/quartz-based kitchen sinks were crushed and the 0.1 - 0.5 mm fraction was sieved out and this fraction was used as particulate material within the meaning of this invention.

Recyclate No. 6 was obtained in an analogous manner from polyester/quartz-based kitchen sinks. For this purpose, kitchen sinks were broken up and the 0.1-0.5 mm fraction was sieved out. This fraction was then used as particulate material in the sense of this invention.

Alternatively, this material preparation can also be applied to kitchen worktops, wash basins, shower trays or bathtubs based on polyester/quartz (or other fillers) as well as acrylate/quartz (or other fillers). Table 18: Strength and index of composite molding cores based on alternative particulate materials material BET** Binder content, [Ma-%] Key figure: BM/BETx100 Strength* N 1. Foundry old stock, black, 0.1-0.5 mm 253 5 2.00 675 2. Nut shell granules, 0.1-0.5 mm 245 4 1.63 723 3.Olive kernel granules, 0.1-0.5 mm 262 4 1.53 747 4. Recycled glass granules 0.1-0.5 mm 115 2 1.74 535 5. Recycled, PMMA kitchen sinks, 0.1-0.5 mm 172 4 2.32 642 6. Recycled polyester kitchen sinks, 0.1 - 0.5 mm 195 4 2.05 605 * the strength was measured on cut test bars 22x22x160 mm ** = BET = theoretical. specific surface in cm ² /g

An example of a composite mold core produced with a foundry old stock (No. 1 in Table 18) is shown in 7 The comparison with the figures in 4 - 6 The darker coloring of the composite mold cores shown is induced by the darker color of the foundry sand compared to the other sands used.

Tests were carried out on some composite molding cores for post-treatment, such as the application of a composite molding shell. The composite molding shell was applied by impregnation and/or coating.

• - mit einer Flut-Grundierung auf Basis eines wässrigen Acrylats (AC3600) in Kombination mit einem 2-Komponenten-Epoxidharz,
• - einer alleinigen Behandlung mit 2-Komponenten-Epoxidharz (2-K-EP) durch Imprägnierung bzw. Beschichtung, sowie optional
• - einer Schwarz-Lackierung.

The treatment of the composite molded part cores was carried out

• - with a flood primer based on an aqueous acrylate (AC3600) in combination with a 2-component epoxy resin,
• - a sole treatment with 2-component epoxy resin (2-K-EP) by impregnation or coating, and optionally
• - a black paint finish.

The 8a shows an example of flood impregnation of a composite molded part core.

8b shows an example of a 2-K-EP coating and subsequent black painting.

The 9a and 9b show a composite molded part after impregnation and coating. The composite molded part core for this composite molded part was the 6c and 6d The composite molded part core shown in the figure is used. In particular, when comparing the representations of the 6c and 6d compared to those of 9a and 9b the homogeneous and full-surface composite molded part shell becomes visible.

The applied composite molded part shell can be very thin, chemically and physically very resistant and/or decorative. The composite molded part shell can itself be surface-coated and/or itself represent a fully colored and functionalized outer layer. Due to the low layer thickness and the possibilities for saving binding agents for producing the composite molded part core, the composite molded part shell can also be comparatively expensive.

The composite molded part core can - since it can be covered and/or protected by the composite molded part shell - be manufactured very inexpensively, light, recyclable, sustainable, with an even further reduced binder content, renewable raw materials, inorganic or organic recyclates or mixtures of these, e.g. old foundry sand, rice husk ash, limestone granulate, ceramic granulate, wood chips, expanded glass, polystyrene, expanded clay and others.

Table 20 shows that the exemplary composite molded parts, as obtained with composite molded part cores as described in this invention, are at least equal to the composite molded parts available on the market - in this case PMMA and polyester-based kitchen sinks - and are usually even better when comparing various technical properties. Table 20: Comparison of new composite molded parts (AD) with composite molded parts available on the market (Sch, E, B, A, M, W., K) Manufacturer sink Resin type Surface roughness Hot-cold test (4000 cycles) Hot-cold test (4000 cycles) Scratch resistance / abrasion Force input Abrasion, Taber Filling level Here quartz sand Cracking Blushing dL [Ma-%] School 1 1 PMMA 1 - - 4 7 0.03 69.5 Sch. 2 2 PMMA 5 3 3.5 4 7 0.03 73 E. 3 PMMA 6 2 6.8 2 8 0.03 69.5 b. 4 PMMA 4 1 2 1 9 0.03 71 A. 5 polyester 2 4 21 4 7 0.08 71 M. 6 polyester 3 4 17 5 6 0.08 70 W. 7 polyester 7 5 17 6 4 0.16 73 K. 8 polyester 8 - - 3 7.5 0.11 71 Embodiment 1 A 2K EP* 4 4 20 3 6 0.08 85 Embodiment 2 B PMMA* 2 3 8 2 7 0.03 87 Embodiment 3 C 2K PU* 2 3 12 2 7 0.04 87 Embodiment 4 D Acrylate** 3 4 17 4 5 0.10 83 * The polymers listed under A to D were used in these examples as the basis for the surface coating ** water-based

The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they, individually or in combination, are superior to the prior art. Technology is new. It is also pointed out that the individual figures also describe features which can be advantageous in themselves. The person skilled in the art will immediately recognize that a particular feature described in a figure can also be advantageous without adopting further features from this figure. The person skilled in the art will also recognize that advantages can also arise from a combination of several features shown in individual or different figures.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 4040602 A1 [0003]
• DE 4407321 A1 [0003]
• DE 4410526 A1 [0003]
• DE 19920719 A1 [0003]

Claims (15)

Composite molded part core comprising a particulate material and an at least partially cured binder which bonds particles of the particulate material to one another, characterized in that a mass fraction of the at least partially cured binder is ≤ 15 mass percent. Composite molded core according to Claim 1 , characterized in that at least one surface of the composite material molded part core is at least partially, preferably completely, covered by a composite material molded part shell. Composite molded part core according to one of the preceding claims, characterized in that a binding ability of the at least partially cured binder can be reduced by an activator, wherein the activator is preferably a temperature application or reagent application, by means of which a chemical and/or physical reaction can be triggered in or with the binder, which reduces the strength of the entire composite molded part core and/or converts the binder into a subsequent product with reduced binding ability. Composite molded part core according to one of the preceding claims, characterized in that the composite molded part core is impregnated at least in sections and/or a composite molded part shell is formed by an impregnate penetrating at least in sections into the composite molded part core, wherein the impregnate preferably comprises a curable polymer, for example a resin, wherein the curable polymer is preferably an epoxy resin. Composite molded part core according to one of the preceding claims, characterized in that the particulate material has a particle size (d ₅₀ Sedigraph or laser diffraction) ≥ 5 µm, preferably ≥ 10 µm, preferably ≥ 20 µm and a particle size (d ₅₀ sieve analysis or laser diffraction) ≤ 3000 µm, preferably ≤ 250 µm, preferably ≤ 100 µm or comprises a sand whose average particle size d ₅₀ (sieve analysis or laser diffraction) is in a range of 5 µm - 10 mm, preferably 10 µm - 5 mm, particularly preferably 20 µm - 1 mm. Composite molded part core according to one of the preceding claims, characterized in that the particulate material comprises at least two components which differ at least in an average particle size d ₅₀ (sieve analysis or laser diffraction). Composite molded core according to one of the Claims 2 - 6 , characterized in that the composite molded part shell comprises a polymer, wherein the polymer is preferably a solid or liquid or disperse polymer, which is preferably selected from a group comprising acrylates, styrene acrylates, silanes, silicones, alkanes, alcohols, urethanes, epoxies, cellulose, methylcellulose, inorganic polymers and mixtures thereof, preferably acrylates, urethanes or epoxies. Composite molded part core according to one of claims 7, characterized in that the composite molded part shell comprises at least one additive, wherein the additive preferably comprises a coloring component, preferably a dye, a color paste and/or a pigment and/or the additive has a Mohs hardness > 4, preferably > 4.5, more preferably > 5. Composite molded part core according to one of the preceding claims, characterized in that a value which corresponds to one hundred times the quotient of the binder content in percent by mass and the theoretical specific surface area in cm ² /g (BET) of the particulate material is less than or equal to 5, preferably ≤ 4.5, further preferably ≤ 4, more preferably ≤ 3.5 and particularly preferably ≤ 3. Method for producing a composite molded part, comprising the steps: - providing a composition comprising a particulate material and ≤ 15 percent by mass of a binder based on the total mass of the composition, - producing a molded composite molded part core by at least partially curing the binder, - producing a composite molded part shell which partially covers at least one surface of the composite molded part core in the composite material. Process for producing a composite material according to Claim 10 , characterized in that the production of the composite material molded part shell takes place at a time and/or location apart from the production of the composite material molded part core and the application of one or more cover layers to the composite material molded part shell, preferably at a time and/or location apart. Process for producing a composite material according to one of the Claims 10 - 11 , characterized in that the at least partial curing of the binder takes place under - exposure to a temperature ≥ 25°C, more preferably ≥ 30°C, more preferably ≥ 40°C, even more preferably ≥ 50°C, most preferably ≥ 60°C, and/or - exposure to a reagent, preferably gassing, preferably with an amine, and/or - exposure to electromagnetic radiation, preferably UV exposure, light exposure and/or IR exposure and/or - by adding a catalyst. Process for producing a composite material according to one of the Claims 10 - 12 , characterized in that a surface of the composite molded part core and/or the composite molded part shell is machined, preferably mechanically machined, wherein the machining preferably comprises at least one step which is selected from a group comprising smoothing, grinding, brushing, dusting, milling, drilling, polishing and deburring. Process for recycling a composite molded part core according to one of the Claims 1 - 9 and/or one according to one of the Claims 10 - 13 manufactured composite material, characterized in that a binding ability of the at least partially cured binder is reduced such that the bond between two adjacent particles of the particulate material is eliminated, preferably under the action of pressure and/or shear force, preferably pressure and/or shear force of a mixer or stirrer. Composite molded part comprising a composite molded part core according to one of the Claims 1 - 8 , wherein the molded part is preferably intended and suitable for use in the kitchen and/or sanitary area, and/or is preferably selected from a group comprising wash basins, sinks, shower trays, bathtubs, bidets, toilets, worktops, furniture or furniture parts, floor coverings, wall coverings and tiles.