WO2018185552A1

WO2018185552A1 - Process for the production of artificial stone

Info

Publication number: WO2018185552A1
Application number: PCT/IB2018/000413
Authority: WO
Inventors: Jan Interwies
Original assignee: N-Tec Gmbh; Cosentino Research & Development S.L.
Priority date: 2017-04-07
Filing date: 2018-03-25
Publication date: 2018-10-11
Also published as: DE102017107591A1

Abstract

The invention relates to a method for manufacturing artificial stone of a polymeric resin and an inorganic filler, wherein the one or a plurality silicon compounds are added to the mass of polymeric resin and inorganic filler, which mass is then placed in a mould and is cured.

Description

Process for the production of artificial stone

The present invention relates to a method for producing artificial stone, artificial stone produced in this way and its use.

The production of artificial stone is known from the state of the art and generally takes place by comminution of an inorganic substrate of natural or artificial origin to a desired grain size or an inorganic substrate of different kinds or different origins with a uniform grain size or as a mixture of different grain sizes and mixing with a reactive polymer resin, bringing into form, compacting, and curing the polymer resin subsequently by polymerisation reaction. As a result, the inorganic substrate or the inorganic filler is embedded in the cured polymer without being chemically bound.

Since the inorganic filler is only surrounded by the polymer, but not bound by a chemical, covalent bond, the disadvantage exists that filler particles are torn out during polishing and, as a result, larger holes or pores are formed, the removal of which is an additional expense.

The same also applies to the use of such an artificial stone, since the surface is easily damaged, for example, during cleaning with abrasive means, but also during normal use.

Typically, an inorganic filler is introduced into a matrix of reactive resin, densified and cured. As inorganic fillers, particles of various composition are used. Used are different Si0₂ compounds such as quartz, cristobalite, tridymite, Al₂0₃ Zr0₂, Ti0₂, B₂0₃ or other metal oxides, glass, carbides or other inorganic, chemically stable, insoluble substrates and dyes of various sizes. The size of the particles used can range from several nm to the mm range. Particular danger is caused by particles in the nm and small μηι range of≤20 μηι, which can cause a silicosis by inhalation of the fine dust.

The particles are blended and mixed with the resin so that the inorganic filler is incorporated into the organic resin matrix.

In order for the reaction to proceed, further substances are required. A starting catalyst is required to initiate crosslinking of the resin molecules. For this purpose, radical initiators such as peroxides or UV initiators are used which initiate the corresponding polymerization reaction thermally, by means of UV light or even at room temperature. Acids and bases, corresponding to the polymer used, may also be used for this purpose. Furthermore, the use of acceleration catalysts is state of the art. These molecules, usually metal organic compounds or organic compounds, are used to speed up the reaction and thereby shorten the time of curing. Metal organic compounds can have different organic ligands. The metal centres used are usually cobalt, titanium, zinc, tin, copper, iron, manganese, zirconium, but also rarer or more valuable metals such as ruthenium, palladium or platinum. Owing to the economy, catalysts are often used which are commercially available in large quantities. These catalysts are generally added to the used resin or to the used resin mixture in small amounts.

The use of certain silanes, vinyl or acrylic silanes in amounts of up to 5% by weight of the resin or resin mixture is also known. For example, 3-methacryloxypropyltrimethoxysilane, MEMO, is used as an adhesion promoter, co-polymer and/or crosslinker for the resin system in unsaturated polyester resins, thermoplastics, MMA resin and polyolefins.

Also known is the reaction of employed polymer resins to larger, more viscous units. This occurs before the resin is put into the reaction mass with the inorganic particles, wherein the resin is being admixed with a mixture of solvent and crosslinking agent or polymerization initiator or pure crosslinking agent or polymerization initiator. As crosslinking agents and polymerization initiators, molecules having unsaturated carbon compounds such as styrene, 1-hexene, 2-methyl-but-3-ene are used.

MEMO has the property of improving the adhesion. There is no formation of a chemical bond to the inorganic filler. Inorganic and organic constituents are still separated and are not linked by chemical or covalent bonds. The inorganic filler is surrounded by the resin and adhered or embedded in the organic matrix.

It is also known to use certain aminosilanes, such as 3-aminopropyltriethoxysilane or 2-aminoethyl- 3-aminopropyltrimethoxysilane, as an adhesion promoter in amounts of up to 5% by weight of the resin or resin mixture, wherein the aminosilanes are being added to the inorganic fillers prior to addition of the inorganic solid into the resin mass so as to pre-treat the solids. They then react at the surface of the filler such as Si0₂ or Al₂0₃ and act, like MEMO when added to the resin, as an adhesion promoter. The inorganic particles are better and more stably embedded in the organic resin matrix than with MEMO or without silane.

In the prior art, there are still problems with the bonding between the inorganic filler and the organic matrix in many areas. Since the grain and matrix are only attached or adhered to one another, the grain can easily be torn out of the matrix under mechanical or chemical stress. This opens up defects which are optically visible or further reduce the stability of the material against mechanical or chemical influences and thus have a strong influence on durability, optics, chemical and mechanical resistance and stability of the material.

After the above-mentioned components are compounded and mixed, the thus obtained raw mass is put into a mould and pressed. The pressure may vary during pressing. The pressure may be applied alone, but also with a thermal pretreatment, under vibration, and/or under vacuum. The material is then tempered for curing. This takes place in furnaces at temperatures of 50 °C to 250 °C or under UV radiation.

There are a number of commercially available products made by the method described

above. They have in common that they are, at least in part, significantly further improvable with regard to some material properties, such as, for example, material hardness, breaking strength, chemical resistance, in particular with regard to acids and bases, but also with respect to water as well as with regard to thermal conductivity or with resistance to temperature-induced stresses and abrasion.

It is therefore the object of the present invention to provide a process for producing artificial stone by which an artificial stone is produced as a result of the process which at least partially overcomes the disadvantages known from the prior art and can be produced economically. An artificial stone produced according to the inventive method and its use are likewise subject matter of the present invention.

The present object is achieved by a process of the type initially described and to which one or more Si compounds are added to the raw mass in an amount between 0.1 and 40% by weight of the total mass, and if, as one or more Si- compounds only monomeric silanes exclusively with aliphatic substituents on the Si atom having a chain length of Ci to C₃ are used, an additional catalyst in an amount of 0.1 to 10 wt.-% of the total amount of added Si compounds is added. In this Si compound the aliphatic substituent on the Si atom can be further substituted by a heteroatom.

However, the use of the latter catalyst is not required when Si compounds are used which have at least one aliphatic substituent with a chain length of at least 7 carbon atoms, an aromatic substituent or which are siloxanes, in particular disiloxanes, and silazanes. Therefore, these alkylsilanes, in all their n- and/or iso-forms, arylsilanes, siloxanes, polysiloxanes and

cyclosiloxanes are particularly preferred within the scope of the present invention.

In investigations in relation to the present invention, it has been surprisingly found that the addition of one or more Si compounds to the initially described raw mass of reactive polymer resin and inorganic filler with optionally present catalysts results in the fact that the raw material is already more easily distributable in the mould, has a higher density and is more compact. The raw mass thus modified shows a thixotropic behavior and is self-leveling. It can be compacted more easily by pressure and vibration, whereby an oily liquid emerges from the previously dry grain, unlike with the unmodified raw mass. The reason for this is considered to be the fact that the added Si compound functions as a lubricant which significantly reduces the friction between the particles of the inorganic filler and thus enables easier and stronger compression.

This oily liquid consists of excess silicon compound, resin, solvent, starting catalyst, accelerating catalyst, solvent, dissolved or colloidal inorganic constituents, and, optionally, the additional catalyst for the silicon compound. After pressing, the surface is already significantly smoother than without the inventive addition of one or more of the mentioned silicon compounds.

It also surprisingly appears that according to the invention the addition of one or more Si compounds, as already described optionally in combination with a corresponding catalyst, together with the polymer resin penetrates into the pores of the inorganic filler by the pressure applied during pressing. This pressure infiltration of the inorganic filler then obviously leads to a reaction between the polymer resin, the Si compound in these pores and, on the pore walls, with the inorganic filler. This results in an increase in the density as well as a greater hardness of the artificial stone produced by the method according to the invention, compared to an artificial stone from the prior art.

There is also an escape of air inclusions contained in the inorganic filler, since the liquid components present in the reaction mixture penetrate into existing pores, displace air contained, and react to form solid structures in the pores as well as in the intermediate spaces.

A further surprising advantage becomes apparent by the fact that the adhesion to paper is significantly reduced and the paper, which is conventionally inserted between the raw material and the mould or between the raw material and the stamp before the pressing as a release agent, can easily be removed after drying. This is not the case in the prior art.To the contrary, in a

conventional prior art method, this paper must laboriously be polished off, which causes considerable costs.

Depending on the composition of the material and the associated leakage of the oily liquid, the paper can be dispensed with altogether. Especially in the case of complicated 3-D moulds, this represents an enormous advantage in the release from the mould. Overall, it should be noted in this context that the effect of easy detachment of the paper used as mould release agent already occurs from an addition of 1 % by weight of Si compound relative to the total mass particularly easily and, starting with the addition of 2% by weight of Si compound, the paper detaches itself after curing. For this reason, an embodiment of the process according to the invention in which at least 1 % by weight of Si compound is added is preferred. Particular preference is given to an embodiment in which 2% by weight of Si compound is added.

Since the paper used as a release agent is warped or gets wavy by wetting, up to 2 cm of material must be removed for a complete removal of the paper by polishing on each side in the prior art. This is not only time-consuming and process-intensive, considerable amounts of material are also lost. According to the invention, this results in a significant cost saving alone for this reason.

On the whole, according to the invention, an artificial stone having significantly improved properties and characteristics can be produced in comparison with an artificial stone produced according to a method from the prior art.

These also in total completely unexpected improvements are, for example, an increase in hydrophobicity and an increased chemical resistance to acid, base and solvent, an increased stain resistance, greater hardness and, as a result, an increase in scratch resistance, a smoother surface and an increased gloss, a significant higher density compared to the the material of the prior art, a better thermal conductivity, the already described better detachment of the paper used as a release agent, a soft feel on touch designated as "soft touch", a generally improved mechanical and thermal stability, an increased melting point, reduced combustibility and improved

UV stability. It is to be understood in this connection that these advantages can be realized individually as well as in combination of several advantages depending on the starting materials used.

It has to be particularly pointed out, in especially when alkylsilanes and/or alkylsiloxanes or generally siloxanes are used, that the resulting artificial stone exhibits regenerative

properties. Investigations in this context have shown that, after treatment of the artificial stone with acetone or after abrasion with a household scrubber's sponge, the artificial stone first loses its brilliancy, but clearly regains shine after 24 hours. If subsequently cleaned with water, the initial gloss value is practically reached again and in some cases even exceeded. This is also done under conditions of artificial ageing where the chemically or mechanically stressed sample was held for 24 to 48 hours under UV irradiation.

The method according to the invention thus makes it possible to obtain an artificial stone which has been improved in a particularly unexpected manner, whereby a considerable cost saving can also be achieved in comparison with the prior art.

For a better understanding of the invention, the process for manufacturing artificial stone is described and explained in detail below. With regard to the following description of the invention, it is noted that no distinction is made between singular and plural with respect to the components used, and in particular with reference to the polymer resin, the filler and the Si compound, a reference to a single compound in each case includes the plurality thereof and vice versa.

Materials used as an inorganic filler are numerous and are subject to virtually no limitation. In particular, there are, for example, quartz, feldspar, basalt, mica, cristobalite, Si0₂, Al₂0₃, SiC, SiN, BN, BC, Si₃N₄, Zr₂0₃, Ti0₂, Fe₂0₃, Zr0₂, CuO, Cu0₂, ZnO, glass, glass fibres, TiC, natural inorganic pigments such as earth colours, mineral white, titanium dioxide, synthetic inorganic pigments such as metal effect pigments, carbon black, white pigments, iron oxide pigments or zirconium silicates and oxides, as well as ceramic fracture. Multiple references are included in this non-exhaustive list, since these compounds can be subsumed under different headings.

As a matter of course, organic pigments or colouring agents can also be added to the inorganic filler so long as they are stable at the temperatures of the heat treatment.

The particulate inorganic compounds are used here as fillers and/or as dyes. Any combinations can be selected.

The size of the inorganic filler used is generally from 0.1 μηι to 10 mm, wherein fillers of the same type, but also of different size and type can be used. The proportion of the inorganic filler is preferably from 50 to 97% by weight of the total mass of the raw mass of inorganic filler, reactive polymer resin and the silicon compound or silicon compounds added in accordance with the invention, as well as any catalysts present.

In order to increase the density and to improve the mechanical stability, it is preferred in a particular embodiment of the method according to the invention to add natural or artificial inorganic particles or powders as support grain with a clearly smaller grain size in the range from 10 nm to

30 μηι. Such supporting grain preferably consists of the above-mentioned materials and its proportion is determined in terms of size, type and colour of the inorganic filler used and is preferably in the range from 5 to 25% by weight of the inorganic filler used.

An addition of support grain is an advantageous feature of a particular and independent embodiment of the method according to the invention because, in this way both inter particle cavities and interstices as well as intra particle pores are filled and thus increases the density.

According to the invention, conventionally used reactive polymer resins for producing artificial stone according to the prior art used as the polymer resin. In particular, these polymer resins are saturated or unsaturated polyester resins, phenolic resins, epoxy resins, polyurethanes, urethane acrylate or polyamide resins. These are preferably used in a proportion of 3 to 40% by weight of the total mass, more preferably in a proportion of 7 to 13% by weight.

In order to cure the polymer resin with a procedurally and economically justifiable duration it is necessary, depending on the polymer resin selected, to provide a corresponding starter in the form of a catalyst, better starting catalyst, and/or an accelerator, also in the form of a catalyst, better acceleration catalyst, to the polymer resin.

It is preferred to add resin initiator or peroxide catalyst to the polymer as a starting catalyst in a proportion of from 0.5 to 5% by weight of the resin and/or accelerator or metal organic catalyst as an acceleration catalyst in a proportion of from 0.1 to 2 % by weight of the resin. For example, peroxide catalysts/initiators, available under the name Trigonox 301 , can be used in an amount of 2 % by weight based on the resin, generally from 0.5 to 5% by weight being possible.

As an acceleration catalyst, for example, cobalt can be used in an amount of 0.2 % by weight, based on the resin, available under the designation Octa-Soligen® Cobalt 6 from Borchers, with amounts of 0.1 to 2 % by weight being possible.

In general, it has to be noted that in this specification references are made to commercially available products which are generally not given in detail by the manufacturer in terms of their composition since these compositions are considered to be trade secrets.

While the above mentioned starting materials are generally known according to their type and amount for the production of artificial stone, the essential effect of the invention, i.e. the described improvement in the properties of the artificial stone, is due to the addition of one or more Si- compounds which are added in an amount between 0.1 and 40% by weight of the total mass and, when as one or more Si compound, only monomeric silanes having exclusively aliphatic substituents with a chain length of Ci to C₃ are used, a catalyst in an amount of 0.1 to 10% by weight of the amount of the Si compound is added to the Si compound. This addition of the catalyst is in principle carried out independently of catalyst already present in the polymer resin and serves exclusively to increase the activity of the Si atoms contained in these compounds, whereby these are able to bind firmly to the filler to form covalent bonds with the inorganic filler via oxygen atoms. For example, a greater hardness of the produced artificial stone is achievable, but other improvements are also possible. In the case of Si compounds exclusively with aliphatic

substituents with a chain length of 1 to 3 carbon atoms only by means of the addition of a catalyst. In the presence of Si compounds having at least one substituent having a chain length greater than 4 carbon atoms, such a catalyst addition is not required. Si compounds with at least one aromatic substituent can also be used in the context of the present invention without the addition of a catalyst.

Suitable catalysts for increasing the activity of these Si compounds with exclusively Ci to C₃ substituents are, in principle, metal organic catalysts, in particular commercial metal organicl catalysts, since they are comparatively inexpensive and readily available in sufficient and in sufficient quality. Particularly good results are obtained for metal centres with organic ligands of the elements titanium, zirconium, cobalt, copper, zinc, tin, iron, manganese, magnesium, aluminium and boron. Organometallic catalysts which contain the metals mentioned are therefore

preferred. However, elements such as vanadium, chromium, nickel, molybdenum, silver, gallium, germanium and bismuth also provide sufficiently good results, usually using only a single type of catalyst for these Si compounds.

Metal organic catalysts with alkyl groups which can be present both in n-form but also in all iso- forms are readily processable.

Examples of some organometallic catalysts which originate from carboxylic acids are octoates, laurates, oxalates, decanates and naphthenates.

Specific examples of such organometallic catalysts are cobalt(ll)2-ethylhexanoate, tin(ll)-2- ethylhexanoate, dibutyltin dilaurate, dioctyltin dilaurate, zincocteate, zinc oxalate, zirconium cteat, zinc 2-ethylhexanoate, copper oleate and copper naphthenate. Other ligands which are useful and therefore important in the context of the present invention are acetate, acetyl acetate, oleate and carboxylate, for example dibutyltin dicarboxylate, zinc acetate, cobalt acetate, bismuth carboxylate.

The acetylacetonates represent a particularly important group with numerous readily available and employable representatives. Particular examples are aluminium(lll)acetylacetonate, Al(acac)₃, calcium(ll)acetylacetonate, Ca(acac)₂, chromium(lll)acetylacetonate, Cr(acac)₃, cobaltic acetylacetonate, Co(acac)₃, ferric(lll)acetylacetonate, Fe(acac)₃, copper(l)acetylacetonate, Cu(acac), copper(ll)cetylacetonate, Cu (acac)₂, manganese(lll)acetylacetonate, Mn(acac)₃, nickel(ll)acetylacetonate, Ni(acac)₂, vanadyl acetylacetonate, V(0)(acac)₂ and zinc

acetylacetonate, Zn(acac)₂, to name only a few.

Another important group which can be used as catalysts are alkoxides and borates. Particular examples of particularly good catalysts are titanium iso-propoxide, titanium tetrabutanolate, zirconium n-propoxide, aluminium iso-propoxide and triisopropyl borate.

These catalysts and/or accelerators can also be used specifically for the functionalisation of the surfaces. For example, artificial stones act strongly anti-bacterial, antifungal and/or antiviral when containing catalysts with Zn, Sn or Cu components.

Aluminum and also zirconium catalysts improve the mechanical and/or chemical resistance of the workpieces.

In order to increase the reactivity and to control the Si compound, it is possible in an independent embodiment of the process according to the invention to add acids or bases to the same, preferably to a proportion in the range from 0.5 to 10% by weight of said silicon compound. This produces hydrolysates and/or condensates of the silicon compounds used, which react with inorganic filler and polymer resin to form essentially covalent bonds, although this reactionin principle also occurs out without addition of acid or base.

After addition and/or compounding of the Si compound with the mixture of inorganic filler, polymer resin, optionally with required catalysts, and optionally with a proportion of support grain, it is mixed until a homogeneous mass is obtained. This modified raw mass is moulded as is generally known, compacted and cured for 5 to 240 minutes at room temperature to 250 °C, preferably at 50 to 190 °C, and/or subjected to UV radiation.

It has proven to be particularly advantageous that the process according to the invention can be varied and adapted with regard to the design of the process steps, the use of the starting compounds and the product quality available. This is, in particular, economically advantageous and allows adaptation to the requirements for different fields of application of the artificial stone to be produced.

In principle, various possibilities of variation, which in each case represent independent embodiments of the method according to the invention, are possible.

In a first variant, as already described hereinbefore, the process is carried out and the one or more Si compounds are mixed with the raw mass produced from inorganic filler, polymer resin and, if appropriate, support grain as well as catalysts, for obtaining the modified raw material which is then moulded or spread as a mass layer, compacted and cured.

According to a second variant, Si compound and polymer, if appropriate with the addition of corresponding catalysts, are first mixed, and then with the prepared inorganic filler.

According to a third variant, Si compound and inorganic filler are first mixed, and then polymer is added and it is mixed again.

In a fourth variant, a raw mass of polymer and inorganic solid is prepared as usual in the prior art and brought into form. The one or more Si compounds are then applied to the raw mass. The application is effected, in particular, by spraying, but can also be carried out in a different manner, such as, for example, printing, pouring or flooding. This is followed by compaction, wherein by exerting the pressure the one or more Si compounds are distributed in the spatially upper region and deep in the already moulded form of the raw mass.

The Si compounds may, in principle, also be used in a suitable solvent in the process according to the invention and this is advantageous in cases where these silicon compounds are usually commercially available dissolved in a solvent. It is also particularly advantageous to use these compounds in a solvent if their viscosity is to be reduced for better processability, for example in spraying.

According to a further, fifth variant of the process according to the invention, the one or more Si compounds are applied in a smaller amount than in the above-described variant or after a pre- compacting of the raw mass.

These variants of the method according to the invention differ in part from the products resulting from the individual variants, which, although to a different extent, basically show the already described advantages over the prior art.

In the artificial stone obtainable according to the first three process variants, the entire raw mass is modified by addition of the one or more Si compounds and is uniform and homogeneous. It is distinguished, in particular, by a greater hardness and chemical resistance, hydrophobicity and greater density, and stress cracks can not be observed or can be observed to a very limited extent only even when heated in a limited part of the surface.

The artificial stone obtainable according to the fourth variant is similar and the advantages described in the first variant are also present with only minor deviations. Since, in this variant, there is usually no absolutely homogeneous distribution of the added silicon compound in the raw mass, small defects or hair cracks in the nm or pm range can occur. However, this is justifiable in many fields of application, the advantages gained clearly outweighing these minor disadvantages.

The artificial stone obtained by the last-described method variant exhibits marked differences to the two other variants in terms of the properties, since the moulded the raw material is only being superficially modified, and the artificial stone exhibits a greater hardness and chemical resistance and hydrophobicity on the modified surface, while the other side is not modified and has properties such as a synthetic stone from the prior art.

This material is particularly useful, for example, for kitchen worktops, wall tiles, floor tiles, facade tiles, 3-D castings, wash basins or shower trays, the surfaces of which are subject to a wide range of stresses, while the opposing surface, the underside of the worktop, is not exposed to these stresses.

These advantageous properties of the process product which can be realized according to the invention result from the three-dimensional cross linking within the entire substrate. In this connection, not only the resins crosslink, as is the case with prior art polymeric artificial stones. Rather cross-linking according to the invention takes place between the organic part of the artificial stone, the reactive polymeric resin, the silicon compound and the inorganic filler. The attached Figure 17 clearly shows the result in the produced artificial stone, and particularly shows the bonding between the inorganic filler, polymer resin or organic part and the employed Si compound.

In the likewise appended Figure 18, the covalent attachment of the polymer resin to the Si compound and the covalent bond of the Si compound to the inorganic filler is shown in an example in which as polymer resin is a polyester, as a Si compound, an amine compound, and as inorganic filler quartz is used. This diagram is intended only for the fundamental and general explanation of the modification according to the invention achieved, but the invention is not limited to the illustrated example.

In summary, the interactions of the individual components of the artificial stone produced by the inventive method are again, by way of example, and without limiting the invention to the illustrated example shown in the accompanying Figure 19.

The particles of the inorganic filler are glued or affixed in the prior art in the matrix. These particles are present in only weakly bound form in the resin matrix and during the polishing process as well as during subsequent use of the substrates, often torn from the matrix entirely under formation of large pores and holes.

According to the present invention, the inorganic and the organic components, particles and/or fillers are chemically bonded within the matrix, so that during further processing steps such as polishing, cutting, separating and roughing operation, as well as in daily use, these particles can not be torn out of the matrix any more, or rather only in a very difficult manner, and therefore no new open pores and/or holes are formed on the surface of the artificial stone.

Particular advantage of the invention is therefore a stable bond of all components present in the substrate with one another, as well as the self-filling or clogging of still open pores, voids and/or cracks before the hardening process by the growth of hybrid polymer structures. I.e. structures with chemical, usually covalent bonds between the inorganic filler, polymer resin and added silicon compound during the reactions between the modified raw mass components, in particular between the employed silicon compounds or their at least partially in situ formed hydrolysates and/or condensates, under the conditions described later, as well as the inorganic and/or organic compounds, particles and fillers.

The invention makes targeted use of the employed starting compounds through the formation of chemical, covalent bonds, or bonds with a high covalent bond proportion, by reacting with each other to form hybrid structures, hybrid polymers. By the growth of the molecules and their cross- linking, even small voids in the nm range are closed or are accrued, and glass-like or massive, hard, stone-like structures are formed, which in turn are mechanically and chemically very stable.

Depending on the use of the Si-compounds and/or their hydrolysates and/or their condensates, the molecular size of the molecule and the molecular growth can be controlled in a defined way. Ideally, short, medium and long-chain silanes, siloxanes optionally, polysiloxanes, or polysilazanes, siliazanes or their hydrolysates and/or condensates as well as silicone resins are employed. These lead to a closest packing, and a strong ball-like, or "cloudy", interwoven molecule growth and, associated therewith or resulting therefrom, to a self-closing of the porous spaces between, between the inorganic fillers, as well as within the fillers themselves. Further, an additional indentation during the reaction and growth process occurs. This is of particular importance when brittle or porous particulate inorganic or organic compounds or fillers are to be used. The growing of hybrid polymer structures into the pores of the fillers interlink these additionally by indentation in addition to chemical bonding and therefore act in a further stabilising way.

For this reason, less expensive fillers, usually highly porous and less solid fillers, can be used without negatively affecting the properties of the final product.

Further, it has been found that due to the growth of the polymers lesser amounts of resin can be used. This is of particular interest because the resin in the material composition is a particularly price-determining component.

Due to the strong growth of hybrid structures and the resulting filling of pores and interstices it has also been found that the admixing of the finest Si0₂ particles, for example cristobalite, having a size≤20 microns, and the associated risk of the health hazards upon mixing and processing the raw materials can partially or completely be omitted.

With very open-pore fillers, for example, the composition can still be selected in an independent embodiment of the method according to the invention so that by the addition of support grain having a grain diameter smaller than the pore diameter of the filler, the pores at least of a part of the inorganic filler are filled as far as possible.

Further, adhesion-promoting reactive groups are ideally selected on the outer sides of the hybrid structures, which crosslink with the likewise introduced fillers or pigments. The reactive groups are generally reactive functional groups, as for example, amino, carbonyl or epoxy groups. In this way, a highly advantageous improvement in adhesion to inorganic fillers yields from the hybrid polymer base. A three-dimensional cross-linking and matrix formation occurs, wherein a pre-silylation of the inorganic particles in the matrix, as it is at least partially done in the prior art, can be omitted.

The hybrid polymers thus obtained therefore have, in their simplest embodiment, already structures which are composed of inorganic and organic components at the molecular level and are chemically bound to one another. On the one hand they therefore have properties of organic polymers, on the other hand also interesting properties of inorganic materials. Thus, substrates can be provided which on one hand have a high flexibility, such as polymers, and can yet be glass-like hard and chemically resistant, such as inorganic materials.

Since these hybrid polymers have no or virtually imperceptible phase boundaries, also excellent optical properties result in the products produced by the inventive process.

The silicon compounds set forth below are preferably used in the present invention: alkyl silanes such as methoxy-, ethoxyslane or chlorosilanes, hexadecyltrimethoxysilane, commercially available under the designation Dynasylan 9116, methyltrimethoxysilane, commercially available under the designation Dynasylan MTMS, M1-Tri methoxy, iso-butyltriethoxysilane , sold under the designation Dynasylan IBTEO, n-octyltriethoxysilane, sold under the designation Dynasylan OCTEO, iso-butyl trimethoxy silane, sold under the designation Dynasylan IBTMO,

methyltriethoxysilane, sold under the designation Dynasylan MTES, hexadecyltriethoxysilane and -trichlorosilan, propyltriethoxysilane, available under the designation Dynasylan PTEO,

propyltriemethoxysilan, sold under the designation Dynasylan PTMO, octyltrimethoxysilane, sold under the designation Dynasylan OCTMO, octyltrichlorosilane, sold under the designation

Dynasylan OCTCS, dodecyltrimethoxysilan and triethoxysilane, octadecyltrimethoxysilane and -ethoxysilan, isooctyltrimethoxysilane and -ethoxysilan, n-butyltriethoxysilane, n- butyltrimethoxysilane.

Aryl silanes such as phenyltriethoxysilane, sold under the designation Dynasylan 9265 and phenyltrimethoxysilane, sold under the designation Dynasylan 9165.

Amino silanes and diaminosilanes such as 3-aminopropyltrimethoxysilane, available under the designation Dynasylan AMMO, DOG-TM 100, 3-aminopropyltriethoxysylan, sold under the designation Dynasylan AMEO, DEG TE 100, Genosil GF 93, 2-aminoethyl-3- aminopropyltrimethoxysilane, available under the designation Dynasylan DAMO, DOG-DiaAmino TM100, N- (n-butyl) -3-aminopropyltrimethoxysilane, triaminofunctional propyltrimethoxysilane, available under the designation Dynasylan TRIAMO, and 3-(2-aminoethylamino)

propyldimethoxymethylsilane, available under the designation Deolink Diamino DM-100.

Fluoroalkylsilanes such as tridecafluorooctyltriethoxysilane, sold under the designation Dynasylan 8261 , nonafluorohexyltrimethoxysilane and Heptadecylfluoroecyltrimethoxysilane.

Epoxysilanes, acetoxysilanes and silicic acid esters such as tetraethylorthosilicate available under the designation Dynasylan A, tetramethyl orthosilicate, available under the designation Dynasylan M, di-tert-butoxydiacetoxysilane, sold under the designation Dynasylan BDAC, and 3-glycidyloxy- propyltrimethoxysilane, available under the designation Dynasylan GLYMO.

In the context of the invention particularly to be emphasized siloxanes and cyclosiloxanes are hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, polydimethylsiloxane and octamethyltrisiloxane.

Examples of in this invention usable silazanes and polysilazanes are as polysilazane,

commercially available under the designation Durazane 1500 Rapid Cure and as silazane hexamethyldisilazane HMDS.

As the silicone resins are for example methylphenylsilicon resin solution, commercially available under the designation REN 80, methoxy functional methylpolysiloxane, sold under the designation MSE 100, silanol functional methylphenylsilicon resin, sold under the designation REN 168 or the product available under the designation 409 Sy.

As examples of usable silane/siloxane mixtures commercially available products Koratect LO-N, an alkylated silane/siloxane mixture Koratect SL 1 , a mixture of isomeric octyltriethoxysilane with iso- octyltriethoxysilane as a main component, Dow Corning Z 6689 containing octyltriethoxysilane, methyltrimethoxysilane, titanium tetrabutoxide and octamethylcyclotetrasiloxane and,

dimethyldimethoxysilane are to be mentioned.

In the present invention generally usable solvents include acetone, isopropanol, ethyl acetate and xylene, but are not limited thereto. In principle any solvents can be used that do not adversely affect the reactions described and which are environmentally friendly.

In a separate and independent embodiment of the process according to the invention UV-initiator may be added to the system. The UV initiator can in principle exert different effects.

First, the use of a passive additional starter is to be mentioned, which is activated by the blocked peroxide. Thereby the reaction rate is increased and the UV-initiator further also has positive effects on the hardness. By subsequent activation by UV light, there is a post-reaction of residues of the UV-initiator, which again positively influences the artificial stone. The yielded effect affects not only the curing reaction, but also the stability of the final product.

Finally, it has to be mentioned that residues of the UV initiator serve as UV quencher and decelerate yellowing of the resin. They not only have an impact on the pigments and the colour of the artificial stone, UV initiators may also act colour enhancing and bring forth even brighter or whiter plates or, on the other hand, darker, more intense coloured artificial stones.

Examples of in the present invention usable UV initiators are benzophenone, ferrocene, aryl diazonium, acetophenone, benzoin, camphorquinone, 1-hydroxycyclohexyl phenyl ketone, 2- hydroxy-2-methylpropiophenone, methylbenzoylformate, 4,4-dihydroxybenzophenone, 4,4'-bis (diethylamino) benzophenone, benzoinmethylether, anthraquinone-2-sulfonic acid sodium salt, as well as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide.

Within the scope of the present invention, particularly preferred silicon compounds, which can be used alone or in admixture, are also described below once again in more detail in connection with the artificial stone obtained with these.

Octyltriethoxysilane may be used pure and as hydrolysate (10%) in an amount between 10 and 20 wt.-%, based on the total weight. The artificial stone obtained with this Si compound is

hydrophobic, slightly oily and slightly harder than without modification by a Si compound. The artificial stone again improves with time gradually in hardness, but not as strong as with

hexadecyltrimethoxy silane.

Using the hydrolysate, the effect is comparable to the concentrate at the beginning. With

hydrolysate, however, a much improved post-reaction in terms of hardness and hydrophobicity is clearly to be noted, in other words, a much better curing.

Sterically more demanding alkylsilanes, such as iso-butyltriethoxysilane or phenyltriethoxysilane, are added separately as a concentrate in an amount from 5 to 20 wt.-% relative to the total mass, whereby very good results in hydrophobicity, hardness and oiliness can be achieved. The obtained surface is very smooth, with the smoothness after polishing being lost to a small extend. The artficial stone then turns slightly rough. Hydrophobicity and hardness improve after a few days by itself.

In combination with long-chain alkylsilanes, silicone resins or mixtures it becomes conspicuous that phenyltriethoxysilane and the other Si compounds individually usable with good results obviously negatively influence one another in their effect. Though in combination a sufficient hardness remains, smoothness and visual appearance, however, are somewhat reduced in comparison to Si compounds when individually used.

When using methylphenylsilicone resin, available under the designation REN 80, hydrophobicity, chemical resistance to acid, base and solvent are improved, the artificial stone has an increased stain resistance, hardness, smoothness, and a higher density, increased scratch resistance, soft touch and thermal stability and is slightly oily. The silicone resin should be dissolved in acetone and diluted to be sprayed. The mixing ratio is generally 1 : 1 or 1 :2 Si compound:solvent.

If the solution is sprayed, it is preferred to apply it at 1 to 2.5 wt.-% based on the total mass. The surface of the artificial stone is highly hydrophobic, hard, well compacted and very scratch resistant. The surface is smooth and has a soft touch.

The methylphenylsilicone resin solution can also be added in pure form, but this leads to the formation of lumps or dries the material severely.Generally, methylphenylsilicone resin solution may be employed in an amount of 1 to 10 wt.-%, based on the total weight.

The product is hard, smooth and hydrophobic after annealing.

The effect of methylphenylsilicone resin solution can greatly be improved when using further additives. For this reason, experimental series were performed with hexadecyltrimthoxysilane and Dow Corning Z 6689 as a mixture. Acetone was used as solvent.

The mixture consists of a solvent in an amount of 25 to 50 wt.-%, methylphenylsilicone resin solution in an amount of 12.5 to 25 wt.-%, hexadecyltrimethoxysilane in an amount of 25 to 50 wt.- %, and optionally Dow Corning Z 6689 in an amount of 25 wt.-% of the mixture and can both be sprayed, in an amount of 2 to 4 wt.-% Si compounds based on the total mass, or an amount of 0.5 to 7 wt.-% Si compounds based on the total mass can be added.

The improvement of the properties is constantly very good. Hydrophobicity, hardness, smoothness and "soft touch" improve significantly or will arise.

Dow Corning Z 6689 is a mixture of several substances and one of the few products which has no negative influence on the effect of individual, pure Si compounds during mixing. It goes well with hexadecyltrimethoxysilane and the methylphenylsilicone resin solution described. By use of this mixture particularly hydrophobicity, improved chemical resistance to acid, base and solvents, stain resistance, hardness, smoothness, density, gloss and scratch resistance are improved compared to the prior art. Also, better release of paper employed as a mould release agent can be observed.

The mixture is generally added in quantities of 1 to 20 wt.-% relative to the total mass of the raw mass, when used alone. The modified product thereby turns very hydrophobic, hard and smooth. A higher compaction occurs, since the raw mass modified with this mixture can be pressed well. In combination with methylphenylsilicone resin solution or hexadecyltnmethoxysilane the properties of Z 6689 are maintained or add up in admixture. The result is again better than used individually.

Aminosilanes and diaminosilanes that can be used in the present invention generally serve as a bonding agent for the inorganic filler. Their use leads to a scale-like growth and leads to a strong reaction with filler grain and attachment to the same.

In this case, short-chain aminosilanes with Ci to C₄ chain length, like short-chain alkylsilanes, separate resin and inorganic filler, when added in about 12 wt.-% relative to the total mass. They promote binding of the filler into the organic matrix.

Medium chain length aminosilanes, i.e. C₅ to C₈, favour the incorporation of the filler into the organic matrix. Scale-like growth also occurs. These aminosilanes can be added up to 20 wt.-% to the total mass.

Aminosilanes and diaminosilanes do not lead to the desired modification on their own, i.e. they do not alone lead to the underlying formation of hybrid polymers. When they are added as a component of a mixture in solvent or in a hydrolysate mixture, they improve the attachment of the grain into the newly formed matrix. Thus, the aminosilane does not interfere with the foramtion of other properties. Also, a greater hardness is detectable in the final product.

Polysilazanes, such as available under the designation Durazane 1500 Rapid Cure, can either be added as replacement for M EMO to the mass in 3 to 5 wt.-% based on the resin, or in 3 to 10 wt.- % relative to the total mass.

Silazanes lead to a drying of the raw mass and do not leak oil after pressing.

By the addition of silazanes the artificial stone is rendered extremely hard and hydrophobic after annealing. However, the modified raw mass foams heavily and is extremely rough and uneven.

Another finding is that the silanes, siloxanes and silazanes are not only responsible for the formation of hybrid polymers, but they also modify the resin itself. After addition, the

silanes/siloxanes/silazanes react with the resin and the hydroxy, oxy, amino, epoxy or ether groups and unsaturated carbon atoms. By the reaction, which proceeds with elimination of water in the presence of acid, or without, the characteristics of the silanes are added to the resin. In addition, unfavourable bonds are disrupted and the now broken, reactive structure is modified by silanes/siloxanes/silazanes. Due to this reaction the original resin is not present at the end anymore - rather a hybrid structure of silane and resin is present. It is a resin modified in situ with hybrid structure and its properties.

The resins, Si compounds and inorganic fillers react during the pressing and subsequent heat treatment allowing for two- or three-dimensional growth, forming spherical, woven structures or flakes, scales or platelets.

The hybrid polymers formed have thermoplastic properties to a certain extent, and this accounts for defects and/or pores being closed during the polishing process.

In certain cases it may be preferred when a pretreatment of the inorganic fillers, before their addition to the mixture, increases the reactivity and the binding of the fillers in the hybrid matrix.ln this case, the silanes hydrolyse and/or condense in situ and are deposited on the surfaces of the fillers, whereby the reactivity is increased.

But also ordinary acids and bases come into account for a reactivity enhancing pre-treatment. For this purpose, acids such as formic acid, acetic acid and nitric acid, and bases such as potassium hydroxide, sodium hydroxide and ammonia are commonly used.

For an illustrative presentation of the invention and the result of the inventive process, reference is made to the accompanying scanning electron micrographs. It is shown:

Figure 1 shows a view of the artificial stone produced by the inventive method with ingrown structures in cross section;

Figure 2 shows a detail of the right third of Figure 1 ;

Figure 3 shows a view of the artificial stone according to the prior art in top view in the same magnification as Figure 1 ;

Figure 4 shows a further view of an artificial stone manufactured according to process variant

3 in plan view;

Figure 5 shows another view of an artificial stone produced by the process of this invention in plan view and with no discernible grain boundaries;

Figure 6 shows a view of an artificial stone produced according to process variant 1 in cross section; with stress lines at the Si0₂ grain;

Figure 7 is a view of the artificial stone according to the prior art in cross section; Figure 8 shows another view of an artificial stone, produced according to process variant 1 in cross section with stress lines at the Si0₂ grain;

Figure 9 shows a further view of an artificial stone manufactured according to process variant

1 in cross section; quartz grain embedded with stress lines, modification of the structure was effected with Si compound with an aliphatic substituent having a chain length >C10;

Figure 10 shows a detail of the left-hand side in Figure 9;

Figure 11 is a view of the artificial stone produced in accordance with process variant 1 in cross section; modification of the structure was effected with Si compound having an aliphatic substituent with a chain length <C6 using a catalyst for activating the Si compound;

Figure 12 is a view of the artificial stone produced in accordance with process variant 1 in cross section; modification of the structure was effected with an aliphatic substituent having a chain length≤ C10 and >C6;

Figure 13 shows a further view of an artificial stone manufactured according to process variant

1 in cross section; Modification of the structure was effected with Si compounds with chain lengths≤C10 and <C6;

Figure 14 shows a further view of an artificial stone manufactured according to process variant

1 in cross section; the modification of the structure was effected by use of iso-butyl triethoxysilane;

Figure 15 shows a further view of an artificial stone manufactured according to process variant

1 in cross section; and

Figure 16 shows another view corresponding to Figure 15.

Figure 1 shows a view of an artificial stone produced by the inventive method with ingrown structures in cross section, wherein the bright area is a quartz grain, the spherical structures in the bright portion result from the inventive modification, that is, result from the introduction of the Si compound, resulting in hybrid polymer structures in pores of the quartz grain. Figure 2 shows the detail of the right third of Figure 1 with those ingrown structures in an enlarged representation. Figure 3 shows a view of an artificial stone according to the prior art in top view in the same magnification as Fig. 1. The uniform, unstructured area represents a quartz grain, while in the remaining part of the representation holes and coarser structures are recognizable.

An artificial stone prepared according to the fifth variant of the method is shown in cross-section in Figure 4 and a phase boundary can be recognised between the region infiltrated by Si to the left in the image and a non-infiltrated region to the right. The right area also corresponds to an artificial stone of the prior art, since this region has not been infiltrated with a Si compound. The higher density and uniformity of the infiltrated areas can be seen in this representation as well as the high degree of homogeneity in the structure.

Figure 5 shows a view of an artificial stone produced by the process of this invention in plan view, wherein the extremely uniform structure is recognizable and that virtually no grain boundaries are visible.

Figure 6 is a view of a site of fracture of the artificial stone according to process variant 1 , while Figure 7 shows a view of a of a site of fracture of the artificial stone according to the prior art at the same magnification in comparison, i.e. the same grain sizes of the inorganic filler were used. It is clearly discernible that the inventive product already shows a much smoother site of racture and a substantially more uniform structure than the artificial stone of the prior art as well as fewer and smaller pores. Conspicuous is further that there are holes caused by broken out filler particles noticeable in Figure 7 which is due to weak bonding to the polymer matrix. The conditions in the novel artificial stone are a result of better binding of all incorporated components with each other and ingrowth of hybrid structures into gaps and into the pores of the filler.

Particularly noteworthy is the fact derivable from Figure 8. This figure, a further view of an artificial stone produced according to process variant 1 in cross-section, shows the fracture surface of a quartz grain in the synthetic stone with stress lines at the Si0₂ grain. It can be seen that the rupture lines form mainly at the joints between matrix and grain. This shows that both are so strongly bonded together that they break in conjunction - and not independently. The grain is under compressive stress due to epitaxial growth, which is demonstrated by the stress lines.

The stress lines are formed not only vertically but also horizontally through the grain. The grain does not break at point defects or defects, but, similar to toughened safety glass, uniformly due to the high tensile and compressive stress.

Figure 9 is a further view of an artificial stone manufactured according to process variant 1 in cross-section. On the left side an embedded quartz grain with stress lines is discernible. In producing the depicted artificial stone a Si compound with an aliphatic substituent having a chain length >Cio was employed, which accounts for the cloudy or spherical, interwoven structures in the image.

The section of the left of Figure 9 shown in Figure 10 shows the cloudy or spherical, interwoven, hybrid polymer structures as well as the smooth texture of the broken-grain Si0₂ with stress lines at the edges.

Figure 11 is a further view of an artificial stone manufactured according to process variant 1 in cross-section. In this example, the modification of the structure was effected with a Si-compound having an aliphatic substituent with a chain length <C₆ using a catalyst for activating the Si compound. Clearly visible the flaky or scale-like hybrid polymeric structures, which are due to the use of the Si compound having a shorter chain length.

In the example of an artificial stone produced by the inventive method shown in Figure 12 a mixture of Si compounds with one aliphatic substituent having a chain length≥C10 and <C6 was used for modifying and there are therefore scale-like and cloud-like structures on the Si0₂ grain discernible as well as stress lines on the grain.

Figure 13 shows another example of the embodiment shown in Figure 12, with higher

magnification to further illustrate the scaly or flake-like and cloudy structures of the hybrid polymer caused by the differently substituted Si compounds. Also, the stress lines on the grain are clearly visible.

Figure 14 finally shows a view of an example of an artificial stone manufactured according to process variant 1 in cross-section, the modification of the structure being effected by iso- butlytriethoxysilane. In this view, the resultant cloud-shaped, hybrid polymer structures as well as stress lines at the Si0₂ particle are also clearly visible.

The attached Figures 15 and 16 show an artificial stone produced according to the process variant 1 in higher resolution, and show that the resulting hybrid structures are three-dimensional, web-like interwoven or form structures, which are very similar to those of convolutions of the brain. It appears that these structures account for a particularly hard and chemically resistant artificial stone. This is particularly true for scratch-resistance and mechanical strength.

It is also clearly discernible that the structures of the quartz in the outer portion of the grain dissolve, and that it is infiltrated. This infiltration takes place at very low temperatures at which the quartz usually is inert to attacks and it is concluded that the transition from the smooth quartz grain to the winding, hybrid polymer structures shown in these figures, prove the reaction with the quartz or Si0₂ and thus the firm chemical bond.

It therefore has to be noted summary that in the figures, the examples of the present invention reflect the strong link of an organic matrix to the inorganic filler. At the border, you can recognize some single molecular particles that are firmly tied to the grain. The particles are distributed throughout the entire grain. It is evidently clear that the tensile and compressive stress on the quartz grain has increased significantly. It can be seen that the rupture lines form mainly at the joints between the matrix and grain. This shows that both are so strongly bonded together that they jointly break, and not independently. The grain is under compressive stress due to the growth the hybrid polymer structures on the grain, which is demonstrated by the stress lines.

The following examples illustrate the invention.

Embodiment 1

This example illustrates the first variant of the process according to the invention. Here, the inorganic filler is first prepared, then the resin, unsaturated or saturated polyester resin, phenol resin, epoxy resin, polyurethane resin or polyamide resin, with the acceleration-catalyst, an organometallic compound with Co, Zn, Sn or Ti and optionally a pigment added to the inorganic filler and stirred.

The modifying additive, i.e. the Si compound selected from silane, siloxane, silazane, silicon resin, and optionally solvent, is added individually or as a mixture, hydrolysate or condensate to the mixture of polymer and inorganic filler and it is stirred. The amount in this case is between 0.1 and 40 wt.-% based on the total mass.

Finally a peroxide is added as a starting catalyst as known. Support grain is then optionally added and the raw mass obtained is now given into the paper-clad mould and covered with a paper on top. The mass is then pressed under high pressure and vacuum, shortly relieved, and then further compressed again at a higher pressure under vacuum. This process can be repeated several times until the appropriate firmness is attained. The so-modified raw mass behaves like the original unmodified moulding compound. Only when filling the form it can be noted that in contrast to the unmodified material the mass is easily distributed and sets already more densely and compact, is self-leveling and evenly

compressed. Even during filling it becomes apparent that the raw mass has thixotropic properties.

The material is thixotropic due to modifying. The material becomes liquid by vibration and pressure and is compressed better and stronger and above all more evenly compacted by the punch or plunger.

During pressing and vibrating an oily liquid exits from the previously dry grain, which consists of an excess of Si compound, resin, solvents, catalysts, solvents and dissolved or colloidal inorganic compounds. Upon exit of this oily liquid it to can be observed that air bubbles are displaced from the interior of the inorganic filler or the particles contained to the outside.

Depending on the employed material the surface is considerably smoother after the pressing and has a significantly reduced adhesion to the paper. The paper can be easily removed and from a proportion of 2 wt.-% Si compound, the paper after curing even comes off by itself after drying.

During the subsequent heat or temperature treatment molecular growth sets in. The material cures during a time of 5 to 240 minutes. The squeezed out oily substance, which is not required for forming the hybrid polymer, by the end of the process still floats on top and is leaked out under the raw mass. Depending on the oiliness of the employed Si compound the paper already comes off by itself or significantly easier than in the prior art.

The surface of the obtained artificial stone is already at this point smooth, harder and more compacted than that of an unmodified artificial stone, which has been produced by a process from the prior art. The paper adheres badly or not at all.

Corresponding to the modification by the Si compound the artificial stone is then directly hydrophobic and extremely hard.

The artificial stone according to the invention is then normally subjected to a final treatment by means of polishing or lapping.

Removal of the paper by polishing systems can be rendered superfluous compared to the prior art because the paper comes off by itself or because of the easier detachment of the paper used as a mould release agent. This allows to dispense with up to two polishing systems, as, according to the invention, up to 2 cm material do not have to be removed on each side. The final treatment can be performed directly. The hydrophobicity and hardness will not be lost, more likely they are increased.

Another saving is achievable due to the oily character of the artificial stone. Because of the leaked out oil on the surface, the plate or slab can rather be polished without the addition of water.

The artificial stone or material obtained is significantly more compact and harder. Since it is a homogeneous unit, and has no pores and cracks outside and inside, no predetermined breaking points are present. Thereby, the mechanical strength by pressure, weight and tension as well as the physical endurability against temperature and temperature variations increases. Generally, the thermal capacity against heat is increased since the melting point is significantly increased. The risk that the plate breaks due to local thermal stress is also minimized because heat or cold are distributed by the homogeneity of the material, and the heat input does not result in stress or tensions.

Embodiment 2

The second process variant is carried out comparable to variant 1. First the inorganic filler is prepared, after which the polymer resin. Subsequently, the Si compound, a mixture of Si compounds or a solution of one or more Si compounds, optionally mixed with a catalyst, is compounded with the polymer resin and this mixture is then added to the inorganic filler, mixed again and further processed as described.

Embodiment 3

A solution of Si compound, optionally with a catalyst, and solvent is prepared.

This solution is, after filling the raw mixture, prepared as in the prior art from polymer resin, optionally with catalysts, and inorganic filler into the mould, sprayed onto the mass. The amount is 0.5 to 30 wt.-% based on the total mass.

No visible change in the raw mass is recognizable.

The raw mass is rendered thixotropic by modifying with the Si compound. The material is liquefied by vibration and pressing and by pressing with the press die, better and more uniformly compacted.

Non-wetted sites are modified by the high creeping capability of the solution of the Si

compound. The excess mixture, which is not required for hybridization of the respective position of the plate, travels through the mass during pressing, included air is driven out and the Si compound reacts at these places with the resin and filler, until either the excess mixture emerges at the surface, or the reaction ends within the modified raw material.

After the pressing of an oily liquid emerges, which consists of an excess of Si compound, resin, solvent, acceleration catalyst, starting catalyst, and dissolved or colloidal inorganic compounds.

Depending on the sprayed amount an equal density of modification and oiliness is achieved as by addition into the mass. The results are analogous to adding to the mass.

Technically, the modification of properties behaves similarly to Embodiment 1. However, minor trade-offs have to be made in relation to density and homogeneity. The mechanical and thermal resistance is significantly increased compared to a stone from a non-modified raw mass.

Embodiment 4

With one exception the procedure is as in Embodiment 3. However, the amount of the solution of the Si compound used is significantly lower. In this way, only the properties of the treated surface or the upper layer of the artificial stone to be produced are altered.

At a low spray amount of 0.1 to≤ 2.0 wt.-% based on the total mass the formation of the oily release layer is almost entirely missing. This provides no advantages in the detachment of the paper. The hardened stone must be further processed by grinding off the paper used as mould release agent.

However, in the material a phase boundary between the modified upper layer and the lower part of the artificial stone is formed. The phases have different properties in terms of heat input, thermal conductivity and heat capacity. Thus, the stability of the material under extreme temperature fluctuations or temperature increase can be improved. The upper denser layer conducts heat much faster and more evenly and distributes the same evenly into the lower layers. Thus, stress fractures can be prevented. A lower addition is advantageous in that properties such as hydrophobicity, chemical resistance and hardness can be increased or improved. These improvements are limited to the treated upper layer.

Below are examples of mixtures of Si compounds and compositions for the raw mass are given to further illustrate the invention. For simplicity, and to a better comparison only quartz was used as the inorganic filler in the examples for the raw mass. Instead of quartz other inorganic fillers and pigments mentioned in the description may be used without further modification. The percentages are given in weight percent based on the total mass of the mixture.

Example 1

This example relates solely to the use of a mixture of long-chain silanes with a chain length of more than 12 carbon atoms.

Hexadecyltrimethoxysilane 38%

Dodecyltriethoxysilane 35%

Tetradecyltrimethoxysilane 15%

Octadecyltrimethoxysilane 2%

Acetone 10%

Example 2

This example illustrates the use of a mixture of short chain silanes with a chain length of 1 to 3 carbon atoms.

Methyltrimethoxysilane 40%

Propyltriethoxysilane 38%

3-Aminopropyltriethoxysilane 2%

Ti-isopropoxid 2.5%

Copper oleate 2.5%

Isopropanol 15%

Example 3

This example relates to the use of a mixture of silanes and siloxanes of different chain lengths. Hexadecyltrimethosxysilane 48%

Octyltriethoxysilane 15%

Methyltrimethoxysilane 12%

Dodecyltriethoxysilane 10%

Octadecyltrimethoxysilane 3%

Octamethylcyclotetrasiloxane 3%

Titaniumtetrabutanolate 3%

Polydimethylsiloxane 5%

Example 4

Si0₂ powder (about 20 microns) 21.90%

Alpha quartz (65 - 200 microns) 3.50%

0.1 -0.4 Alpha Quartz 30.45%

0,5 - 1 ,0 Alpha Quartz 30.45%

Unsaturated polyester resin 9.00%

Pigments 2.18%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Hexadecyltrimethoxysilane 0.76%

Dodecyltriethoxysilane 0.70%

Tetradecyltrimethoxysilane 0.30%

Acetone 0.20%

Octadecyltrimethoxysilane 0.04%

Example 5

Si0₂ powder (about 20 microns) 2 .90%

Alpha quartz (65 - 200 microns) 3.50%

0.1 - 0.4 Alpha Quartz 30.45%

0,5 - 1 ,0 Alpha Quartz 30.45%

Unsaturated polyester resin 9.00%

Pigments 2.18% Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Hexadecyltrimethoxysilane 1.20%

Methyltrimethoxysilane 0.60% n-Octyltrimethoxysilane 0.14% iso-Octyltrimethoxysilane 0.04%

Acetic acid 60% 0.02%

Example 6

Si0₂ powder (about 20 microns) 21.90%

Alpha quartz (65 - 200 microns) 3.50%

0.1 - 0.4 Alpha Quartz 30.45%

0,5 - 1 ,0 Alpha Quartz 30.45%

Unsaturated polyester resin 8.00%

Pigments 2.18%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Methyltrimethoxysilane 1.5%

3-Aminopropyltriethoxysilane 0.50%

(3-Glycidyloxypropyl)trimethoxysilane 0.31 %

Ti-isopropoxid 0.12%

Copper oleate 0.12%

Isopropanol 0.45%

Example 7

Si0₂ powder (about 20 microns) 21.70%

Alpha quartz (65 - 200 microns) 4.00%

0.1 - 0.4 Alpha Quartz 29.95%

0,5 - 1 ,0 Alpha Quartz 29.95%

Unsaturated polyester resin 9.70% Pigments 2.68%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Polydimethylsiloxane 0.8%

Octamethylcyclotetrasiloxane 0.5%

Hexamethyldisiloxane 0.2%

Example 8

Si0₂ powder (about 20 microns) 21.00%

Alpha quartz (65 - 200 microns) 4.50%

0.1 - 0.4 Alpha Quartz 29.30%

0,5 - 1 ,0 Alpha quartz 29,30%

Unsaturated Polyester Resin 11.00%

Pigments 2.08%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Methyltrimethoxysilane 0.78%

Hexadecyltrimethoxysilane 0.65%

Polydimethylsiloxane 0.65%

2- Aminoethyl-3-aminopropyltrimethoxysilane 0.11 % Tetraethylorthosilicate 0.11 %

Example 9

Si0₂ powder (about 20 microns) 21.30%

Alpha quartz (65 - 200 microns) 3.40%

0.1 - 0.4 Alpha Quartz 30.15%

0,5 - 1 ,0 Alpha Quartz 29.95%

Unsaturated polyester resin 9.00%

Pigments 2.18%

Peroxide starter 0.2%

3- Methacryloxypropyltrimethoxysilane 0.3% Cobalt accelerator 0.02%

Methyltrimethoxysilane 1.40%

Methyltriethoxysilane 0.53%

Dimethyldimethoxysilane 1.39%

Titanium tetrabutanolate 0.18%

Example 10

Quartz powder (about 10 microns) 18.30%

Quartz (50 - 150 microns) 5.1 %

Zirconium oxide (Zr₂0₃) (0, 1 - 0,4 mm) 35.72%

Alpha quartz (0,5 - 1 mm) 21.00%

Epoxy resin 13.00%

Pigments 2.18%

Peroxide starter 0.5%

3-Methacryloxypropyltrimethoxysilane 0.15%

Cobalt accelerator 0.05%

Dodecyltriethoxysilane 1.5%

Octadecyltrimethoxysilane 0.5% n-Octyltriethoxysilane 1.0% n-Hexyltrimethoxysilane 0.5%

Propyltrimethoxysilane 0.4%

Dioctyltin laurate 0.1 %

Example 11

Quartz powder (about 20 microns) 25.50%

Alpha quartz (50-200 microns) 8.43%

Aluminium oxide (0.1-0.6 mm) 27.98%

Zirconia (0.6 to 1.2 mm) 26.76%

Phenolic resin 13.00%

Pigments 1.00%

Peroxide starter 0.5%

3-Methacryloxypropyltrimethoxysilane 0.25% Cobalt accelerator 0.08%

Methyltriethoxysilane 2.3%

Isobutyltrimethoxysilane 0.5%

Isooctyltriethoxysilane 0.2%

Zinc acetylacetonate 0.35%

Iron acetylacetonate 0.15%

Example 12

Alumina powder (about 20 microns) 19.90%

Alpha quartz (80 - 200 microns) 7.50%

Alumina (01- 0.5 mm) 29.70%

Alpha quartz (0,5 - 1 ,5 mm) 29.70%

Polyamide resin 7.10%

Pigments 3.25%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.1 %

Cobalt accelerator 0.05%

Methylphenylsilicone resin 0.5%

Hexadecyltrimethoxysilane 1.0% n-Octyltrimethoxysilane 0.25%

Decamethylcyclopentasiloxane 0.25%

Acetone 0.5%

Example 13

Si0₂ powder (about 20 microns) 21.90%

Alpha quartz (65 - 200 microns) 3.50%

0.1-0.4 Alpha Quartz 30.45%

0,5 - 1 ,0 Alpha Quartz 30.45%

Unsaturated polyester resin 9.00%

Pigments 2.18%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02% Hexadecyltrimethosxysilane 1.33% iso-Butyl trimethoxysilane 0.46%

Octyltriethoxysilane 0.08%

Methyltrimethoxysilane 0.08%

Octadecyltrimethoxysilane 0.02%

Titanium tetrabutanolate 0.03%

Example 14

Si0₂ powder (about 20 microns) 21.90%

Alpha quartz (65 - 200 microns) 3.50%

0.1-0.4 Alpha Quartz 30.45%

0,5 - 1 ,0 Alpha Quartz 30.45%

Unsaturated polyester resin 9.00%

Pigments 2.18%

Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Hexadecyltrimethoxysilane 0.67%

Polydimethylsiloxane 0.66% iso-Butyl trimethoxysilane 0.46%

Octyltriethoxysilane 0.08%

Methyltrimethoxysilane 0.08%

Octadecyltrimethoxysilane 0.02%

Titanium tetrabutanolate 0.03%

Example 15

Si0₂ powder (about 20 microns) 21.90%

Alpha quartz (65 - 200 microns) 3.50%

0.1-0.4 Alpha Quartz 30.45%

0,5 - 1 ,0 Alpha Quartz 30.45%

Unsaturated polyester resin 9.00%

Pigments 2.18% Peroxide starter 0.2%

3-Methacryloxypropyltrimethoxysilane 0.3%

Cobalt accelerator 0.02%

Hexadecyltrimethoxysilane 0.90%

Polydimethylsiloxane 0.20%

iso-Butyl trimethoxysilane 0.64%

Octyltriethoxysilane 0.10%

Methyltrimethoxysilane 0.10%

Octadecyltrimethoxysilane 0.03%

Titanium tetrabutanolate 0.03%

It has generally to be noted further that one of the mixtures of silicon compounds may be used as a substitute for 3-methacryloxypropyltrimethoxysilane in an amount of 3 to 50 wt.-% based on the resin or with 0.1 to 40 wt.-%, based on the total mass can be used.

With a low amount of 1 to 3.5 wt.-%, based on the resin, the hydrophobicity is formed only moderately after the heat treatment. At higher concentrations of 5 wt.-%, based on the resin the achievable hydrophobicity is significantly better. The hydrophobicity again improves significantly after 1 and 2 days. The same applies to hardness, it is already well immediately after the heat treatment, but it is extremely well pronounced after 2 days, suggesting a post-reaction.

Visually, the artificial stone appears very smooth, the gloss is significantly increased compared to an unmodified reference. This is already clearly detectable at an addition of 1 to 7 wt.-% based on the resin. From an amount of 20 wt.-%, based on resin, the smoothness is lost, and the artificial stone becomes rough and must then be polished more intensely.

Using the hydrolysate, the effect is comparable to the concentrate at the beginning. With the hydrolysate, however, a significantly improved post-reaction in terms of hardness and

hydrophobicity is clearly noted.

In the scanning electron microscope a layered or scaly growth is noted short chain silanes, with long-chain silane a spherical interwoven growth. In a mixture of long- and medium or short-chain silanes the growth of the long-chain silanes dominates and spherical structures emerge.

The mixture of silicon compounds may be used with 0.75 up to 30 wt.-% based on the total mass. The hydrophobicity and hardness is significantly improved with this method. What is striking is the variation of the roughness, between 20 and 10 wt.-%the artificial stone is very rough, between 3% and 5% it is smooth and between 0.5 % and 2.5 % very smooth.

The best results are obtained based on 1 to 2.5 wt.-% based on the total mass. Hydrophobicity, hardness, chemical resistance and scratch resistance are significantly increased. The artificial stone is optically smooth with high gloss. The surface is oily, the paper used as mould release agent can be taken off very easily.

Silane and/or siloxane mixture may pure be sprayed onto the raw mass in an amount of 0.5 to 4 wt.-% based on the total mass, or dissolved in solvent 1 : 1.

Hydrophobicity, hardness and chemical resistance are significantly improved. With sufficient addition, from 1 wt -%, the surface becomes oily. Using less than 1 wt.-%, it is slightly oily or it remains dry when less than 0.5 wt.-% are used. If the silane mixture further diluted, more solution must be applied. It is important that the amounts given are adhered to with respect to the Si compound.

When a solution of Si compound or compounds sprayed, it is preferred to apply the same with 0.5 to 2.5 wt.-% based on the total mass. The surface of the artificial stone becomes highly hydrophobic, hard, is well compacted and very resistant to scratching or abrasion. The surface is smooth and has a soft touch.

Claims

1. A process for producing artificial stone from a polymer resin and an inorganic filler,

characterised in that

one or a plurality of Si compounds are added in an amount between 0.1 and 40 % by weight of the total mass and,

when used as a single or a plurality of silicon compounds only monomeric silanes having only aliphatic substituents on the Si atom with a chain length of Ci to C, an additional catalyst in an amount of 0.1 to 10 wt .-% of the total amount of Si compounds is added.

2. The process according to Claim 1 , characterized in that

the one or a plurality of silicon compounds is selected from the group comprising silanes, siloxanes, silazanes, and silicone resins.

3. The process according to claim 1 or 2, characterized in that

the metal organic catalyst present in addition to the Si compound is, in particular, a metal organic catalyst containing Ti, Zr, Co, Cu, Zn, Sn, Fe, Mn, Mg, Al or B.

4. The process according to any one of the preceding claims, characterized in that

the inorganic filler is one or more members of the group comprising quartz, mica, feldspar, broken ceramics, Si0₂, Al₂0₃, Zr₂0₃, Ti0₂, Fe₂0₃, Zr0₂, CuO, Cu0₂, ZnO, SiC, glass, glass fibres, TiC, metal oxides generally, alumo silicates, natural inorganic Pigments, such as earth colours, mineral white, titanium dioxide, synthetic inorganic pigments, such as metal effect pigments, carbon black, white pigments, iron oxide pigments or zirconium silicates and oxides, as well as ceramic fracture.

5. The process according to any one of the preceding claims, characterised in that

the inorganic filler is contained in a proportion of 50 to 97% by weight of the total mass and has a grain size of 0.1 μηι to 10 mm.

6. The process according to any one of the preceding claims, characterized in that

the polymer resin is a saturated or unsaturated polyester resin, a phenolic resin, an epoxy resin, a polyurethane resin, urethane acrylate or a polyamide resin.

7. The process according to any one of the preceding claims, characterised in that

the polymer resin is contained in a proportion of 3 to 40 % by weight, in particular in a proportion of 7 to 13 % by weight of the total mass.

8. The process according to any one of the preceding claims, characterized in that

the polymer resin an initiator or peroxide catalyst in a proportion of 0.5 to 5 % by weight of the resin and/or accelerator or metal organic catalyst in a proportion of 0.1 to 2 % by weight of the resin and/or acids or bases are added to one or a plurality of compounds from the group consisting of silanes, siloxanes, silazanes and silicone resins in a proportion in the range from 0.5 to 5% by weight of the silicon compound or silicon compounds.

9. The process according to any one of the preceding claims, characterized in that

the group consisting of silanes, siloxanes, silazanes and silicon resins comprises alkylsilazanes, arylsilanes, aminosilanes, diaminosilanes, fluoroalkylsilanes, epoxysilanes, acetoxysilanes, silicic esters, alkylsiloxanes, cycloalkylsiloxanes, alkylsilazanes, alkyldisilazanes, polysilazanes, methylphenylsilicone resins, methoxy-functional methylpolysiloxane resins, and silanol-functional methylphenylsilicone resins, and mixtures thereof. The silane, siloxanes, silazanes, and silicone resins include silanes, siloxanes, silazanes and silicone resins.

10. The process according to any one of the preceding claims, characterized in that

the one or plurality of Si compounds are dissolved in a solvent.

11. The process according to any one of the preceding claims, characterized in that

the compaction is in one or more steps effected by vibrating, by exerting pressure and/or applying vacuum.

12. The process according to any one of the preceding claims, characterized in that

natural or artificial inorganic particles or powders with a size in the range from 10 nm to 30 μηι are further added as support grain in a proportion between 5 to 25% by weight of the inorganic filler.

13. The process according to any one of the preceding claims, characterized in that

the curing is carried out by a heat treatment of 5 to 240 minutes at a temperature in the range from 50 to 250 °C.

14. The process according to any one of the preceding claims, characterized in that

the polymer resin is first mixed with the inorganic filler, and then the one or plurality of Si compounds are then added and mixed again, first the one or plurality of Si compounds are mixed with the polymer resin, and the inorganic filler is then added and mixed again, first one or plurality of Si compounds are mixed with the inorganic filler, and the polymer resin is then added and mixed again, or the polymer resin is first mixed with the inorganic filler, moulded and then the one or plurality of Si compounds subsequently applied.

15. Artificial stone produced by a process according to any one of the preceding claims.

16. An artificial stone according to claim 15 in the form of a plate , tile or slabs and in particular in the form of a kitchen worktop, a floor tile, a wash basin, a shower tray, a moulded 3-D article, or a wall or facade element.