Title of Invention	MOLDED PLASTIC BODY AND METHOD FOR PRODUCING THE SAME
Abstract	The invention relates o a molded plastic body (1) which is produced from a cured reaction mixture (2). Said reaction mixture (2) is pourable in the non-cured state and comprises 50 to 90% by weight, based on the reaction mixture (2), of an inorganic particulate filler (3), a cross-linking agent (4), and 10 to 50% by weight, based on the reaction mixture (2), of a binder solution (5). Said binder solution (5) comprises a monomer and a polymer dissolved therein. The inventive molded plastic body is characterized in that the percentage of the cross-linking agent (4) admixed to the binder solution (5) is more than 10% by weight based on the percentage of the monomer in the binder solution (5). The invention also relates to a method for producing the molded plastic body.

Title of Invention

MOLDED PLASTIC BODY AND METHOD FOR PRODUCING THE SAME

Abstract

The invention relates o a molded plastic body (1) which is produced from a cured reaction mixture (2). Said reaction mixture (2) is pourable in the non-cured state and comprises 50 to 90% by weight, based on the reaction mixture (2), of an inorganic particulate filler (3), a cross-linking agent (4), and 10 to 50% by weight, based on the reaction mixture (2), of a binder solution (5). Said binder solution (5) comprises a monomer and a polymer dissolved therein. The inventive molded plastic body is characterized in that the percentage of the cross-linking agent (4) admixed to the binder solution (5) is more than 10% by weight based on the percentage of the monomer in the binder solution (5). The invention also relates to a method for producing the molded plastic body.

Full Text	WO 2006/048214 PCT/EP2005/011627 1 Schock GmbH Gmiinder Strasse 65, D-73614 Schomdorf Molded Plastic Body and Method for Producing the Same The invention relates to a molded plastic body according to the preamble of claim 1 and a method for producing a molded plastic body according to the preamble of the independent claim. Generic molded bodies are used for example in the kitchen and bathroom, in particular as sinks, working surfaces, shower trays or the like. In these applications it is especially important that the molded bodies can be easily and thoroughly cleaned, and have high resistivity to mechanical and thermal loads and especially to cyclic thermal loads in conjunction with water or water vapor. DE 38 32 351 Al discloses molded plastic bodies according to the preamble of claim 1. Matched to the mass of the monomer in the binder solution, in the prior art a so-called crosslinking agent is added which causes three-dimensional crosslinking of the polymer chains among one another and thus increases the hardness and solvent resistance of the molded body which has been produced. The upper limit of the proportion of crosslinking agent is approximately 4% by weight relative to the monomer proportion. WO 2006/048214 PCT/EP2005/011627 2 A higher proportion of the crosslinking agent, depending on the particle size of the inorganic particulate filler, leads to different results which are however undesirable. If for example the proportion of crosslinking agent is increased when using a filler with a very small particle size, this leads to the molded bodies tearing in the course of shaping polymerization. For coarser fillers conversely an increase of the proportion of crosslinking agent leads to much more visible, in particular white regions on the surface or directly under the surface, with a distribution which is moreover irregular, and the associated molded body does not meet the quality requirements imposed on appearance. DE 199 49 461 Al discloses a curable casting mass which contains a proportion of 2.5% by weight of the crosslinking agent (relative to the monomer content of the binder solution) in the binder solution formed from the monomer (MMA) and polymer (PMMA). Tn some of the described embodiments another crosslinking agent which is different from the crosslinking agent in the binder solution is not added to the binder solution, but to a dye pigment dispersion. The molded parts produced accordingly do not have the properties which can be achieved by this invention, especially with respect to attainable smoothness of the surface and the outstanding cleanability which can be achieved thereby. DE 195 21 638 Al discloses a process for producing highly-filled plastics with a sparkle effect, with a filler suspension with a content of crosslinking monomers given at preferably 0.1 to 5% by weight relative to the monomer content. JP 09 067497 A and JP 63 068655 A likewise disclose reaction mixtures which contain crosslinking agents and which however also are not castable in the uncured state. The object of the invention is to make available a generic molded plastic body and the pertinent production process which overcome the disadvantages of the prior art. In particular the molded body should have good usage properties, especially good care properties and high resistance WO 2006/048214 PCT/EP2005/011627 3 to mechanical and thermal loads, and high visual quality. The pertinent production process should easily and economically yield molded bodies of high mechanical and visual quality. This object is achieved by the molded body defined in claim 1 and by the production process defined in the independent claim. Special embodiments of the invention are defined in the dependent claims. In a molded plastic body which is produced from a cured reaction mixture, the castable reaction mixture in the uncured state having an inorganic particulate filler with a portion of 50 to 90% by weight relative to the reaction mixture, a crosslinking agent, and a binder solution with a proportion from 10 to 50% by weight relative to the reaction mixture, the binder solution having a monomer and a polymer dissolved therein, the object is achieved in that the proportion of the crosslinking agent is more than 10% by weight relative to the proportion of the monomer in the binder solution. The molded body is produced preferably in a casting mold. It is quite surprising that on the basis of aproportion of the crosslinking agent of approximately 3% by weight relative to the monomer portion, upon an increase especially the visual properties of the molded bodies produced are first degraded in order to again distinctly improve when the proportion is increased further. Especially for an increase beyond 10% by weight, molded bodies are surprisingly obtained which with respect to wear resistance, scratch resistance and ease of cleaning combine an optimum of these properties. According to the invention a uniform distribution of small polymer regions is achieved which no longer exhibit the negative properties of spot formation and still adequately stabilize the molded body which has been produced in order to prevent tearing during and after forming. Moreover a closed surface is formed which in addition also combines haptically distinct advantages over molded bodies from the prior art and a resistant surface with high visual appeal. The surface has improved resistance to falling objects and/or higher scratch resistance, and is also more resistant to hot surfaces. WO 2006/048214 PCT/EP2005/011627 4 The attainable usage properties also depend on the grain size of the filler used. Fillers with a grain size less than 0.05 mm can be referred to as fine fillers for many applications. When using these fine fillers the surface is generally smooth and can be especially easily cleaned. However the visibility of scratches is increased, in a hot pot test dulling can occur and the abrasion resistance is less compared to molded bodies with coarser fillers. When using coarser filler there is conversely generally higher resistivity to mechanical and thermal stresses, but brightening in hot/cold cycle test and in the water vapor test can occur, for example under the action of hot water. Moreover roughened areas can occur in the region of the sink bottom. Ease of cleaning of molded bodies produced in this way is generally less. Nor does a combination of fine and coarse fillers lead directly to an optimum result. Both for fine and also coarse fillers however a further improvement of usage properties can be achieved when the proportion of the crosslinldng agent is more than 10% by weight, preferably more than 20 and in particular between 20 and 30% by weight, each relative to the proportion of monomer in the binder solution. Preferably a crosslinking agent is used which polymerizes more quickly than the other polymerizable binder solution. In this way an especially hard surface with correspondingly good usage properties is produced. The crosslinking agent is preferably a bifunctional or multifunctional monomer or polymer, in particular a bifunctional or multifunctional acrylatc or methacrylate, such as for example ethylene glycol dimethacrylate or trimei:hylolpropane trimethacrylate. Another possible crosslinking agent is pentaerythritol triacrylate or pentaerythritol tetraacrylate or glycerin dimethacrylate. Research has shown that the crosslinking agent bisphenol- A-ethoxylate(2)dimethacrylate in spite of a proportion of binder solution which is high according to the invention does not deliver the desired results, for which reason in one preferred embodiment of the invention this crosslinking agent is not suited, but other crosslinldng agents are preferred, in particular trimethylol propane trimethacrylate or one of the aforementioned crosslinking agents. It can also be advantageous to use a combination of two or more such crosslinking agents. The overall designation acrylate can thus comprise both acrylates and also methacrylates. WO 2006/048214 PCT/EP2005/011627 5 The proportion of the binder solution is between 10 and 45%, in particular between 15 and 40%, and preferably between 20 and 35% by weight, each relative to the reaction mixture. At these percentages the crosslinking agent with its proportion which is high according to the invention is not attributed to the binder solution. Monomers can be in particular styrene, acrylic acid or methacrylic acid or its esters. In one special embodiment the binder solution has a mixture of methyl methacrylate and polymethyl methacrylate, or a mixture of methyl methacrylate and a polymer, in particular a mixture of methyl methacrylate and a homopolymer or copolymer of methyl methacrylate, the copolymer preferably containing the comonomer ethylmethacrylate or butyl methacrylate. The ratio of the proportions by weight of the polymer to the monomer in the binder solution is between 1:1 and 1:10, in particular between 1:2 and 1:7 and preferably between 1:3 and 1:5. As a rule, the size of the filler particles used and the required proportion of the binder solution in particular interact with one another such that when the proportion is increased coarser filler particles of the proportion of binder solution tend to be able to be reduced. The proportion of particulate inorganic filler is preferably between 55 and 85% by weight, in particular between 60 and 80% by weight and preferably between 65 and 75% by weight, each relative to the reaction mixture. In this case it is preferably a mineral inorganic filler, in particular a crystalline filler such as for example silica sand. Preferably the filler particles have a Mohs hardness of more than 5, in particular more than 6 and preferably approximately 7. This applies in any case to the overwhelming proportion of the filler particles used. For technical and economic reasons the use of silicon dioxide with a Mohs hardness of approximately 7 is preferred. Alternatively or in addition also other and in particular harder filler particles can be used which are obtained naturally or synthetically. Examples here include the corresponding glass, silicon carbide, aluminum oxide, or carbon in the diamond modification. WO 2006/048214 PCT7EP2005/011627 6 With respect to the hard layer near the surface, due to the high proportion of crosslinking agent comparatively soft fillers with a Mohs hardness of less than 5 are possible, especially those with a Mohs hardness of 3 to 4, such as for example calcium carbonate or the like. Preferably use is made of naturally obtained silica sands. Especially those silica sands are advantageous which are of high chemical purity, in particular with a low content of iron oxide, and moreover which occur with a very narrow particle size range, for example between 0.05 and 0.3 mm, with a predominant mass proportion between 0.1 mm and 0.2 mm. These silica sands are offered for example by the DORFNER company under the trade name GEBA, see http://wvvw.dorfher.de. The reaction mixture cures with unswollen filler particles and in the uncured state cannot be cast, so that all the crosslinking agent which has been added to the binder solution is available for crosslinking of the binder solution. Preferably the reaction mixture moreover has a substance which prevents settling of filler particles, in particular a thixotroping agent. In this way warping of the polymerized molded body will be prevented. The proportion of the substance which prevents settling of filler particles is less than 1% by weight, relative to the reaction mixture, in particular less than 0.5% by weight, and preferably approximately 0.15% by weight. fn one special embodiment of the invention the reaction mixture moreover has dye pigments. In particular the ease of cleaning of the molded bodies can thus be improved for example in that in the entry areas of public buildings due to the coloring of the molded bodies dirt is not overly conspicuous. Conversely, in areas with increased hygiene requirements, such as for example hospitals or swimming pools, dirt can be clearly visible due to the coloring of the molded plastic bodies. The dye pigments can be uniformly or unevenly distributed depending on the application. The dye pigments can also be prepared in a dye pigment dispersion which is later added to the WO 2006/048214 PCT/EP2005/011627 binder solution and mixed with it. In one embodiment of the invention the dye pigment dispersion does not contain any crosslinking agent, but the entire crosslinking agent is added to the binder solution as long as it does not contain any dye pigments or in any event as long as it is not mixed with a dye pigment dispersion. In addition to inorganic dye pigments, also organically based dye pigments can be used, for example also an additional filler material in particle form with a size up to a few millimeters which is formed by polymerization with other included inorganic filler particles. Moreover by adding dye pigments it is possible to assign signal effects to the molded plastic bodies which have been produced, for example molded plastic bodies that are colored as required, such as for example tiles, in commercial areas can mark stop lines, walkways and driveways or the like, or also a floor area with increased slip resistance can be delineated from a bordering floor area with normal slip resistance in a recognizable manner. Preferably the filler particles after polymerization on the surface of the usage side are coated with a closed layer of polymerized mass. This improves especially the cleanability. Studies of molded plastic bodies produced according to the invention have shown that a high proportion of crosslinking agent in the binder solution does not effect shrinkage of the binder matrix away from casting mold surface, but that rather the casting'mold surface is perfectly reproduced by the produced molded body. The surface roughness which can be ascertained on the produced molded body corresponds to the surface roughness of the casting mold surface and can be set exactly, for example by working the casting mold surface in a specific manner in order to prepare the surface topography desired on the molded body. In one embodiment the casting mold surface is provided with a defined surface structure. The casting mold surface is shaped exactly. The differences in contour of the casting mold surface along a curved path and the contour of the molded body along the corresponding curved path are less than 5 μm, in particular less than 2 μm, and preferably less than 1 μm. WO 2006/048214 PCT/EP2005/0J1627 8 The high proportion of the crosslinking agent in the binder solution on the surface of the molded body does not cause the protrusion of filler particles near the surface which is known in the prior art and which is to some extent even required with respect to the desired hardness by the shrinking back of the surrounding binder matrix which leads to a surface topography, but the reaction mixture is tensioned in the cured state over the filler particles near the surface and thus results in the extremely smooth surface. Thus for example for the molded bodies according to the invention, on a section between two filler particles near the surface, aside from topographies of the casting mold surface, at the filler content according to the invention, as is described for example in the embodiment of formulation 3 explained below, the maximum "height difference" is less than 5 urn, in particular less than 3 urn and preferably less than 2 μrn, in particular less than 1% of the length of the section. The high degree of crosslinking is also confirmed by the low swelling, especially of the layers of the produced molded body near the surface. Thus in a swelling test according to accepted practice in polymer chemistry, especially when embedded in methyl methacrylate at atmospheric pressure and room temperature for an interval of 20 hours with the visible side layer of the molded plastic bodies according to the invention only a volumetric increase of less than 10% occurs, relative to the initial volume, while in molded bodies from the prior art the volumetric increase under the same conditions is generally more than 20%. The measurement of the volume increase for highly filled materials, as in this case, yields greater relative increases compared to measurement of the mass increase. By preference glossy particles which induce a metallic gloss in the produced molded bodies are added to the reaction mixture. In this connection in particular glossy particles are used which do not have their own color, but for example due to coatings and the interference which occur thereby cause color phenomena for the viewer. This is associated not only with outstanding visual appearance, but also usage properties are improved. Suitably coated mica flakes are especially preferred with respect to the layer material and/or layer thickness. WO 2006/048214 ' PCT/EP2005/011627 9 The invention also relates to a process for producing a molded plastic body as described above, the process being characterized in that more than 10% by weight of a crosslinking agent relative to the proportion of the monomer in the binder solution are added to the not yet cured reaction mixture. By preference the mold is filled with the reaction mixture as a dispersion and then the polymerization process is started from the mold part which forms the usage side. Starting takes place conventionally by heating up the pertinent mold part. The reaction mixture is polymerized proceeding from the usage side to the opposite side of the molded body to be produced. Preferably the mold part which forms the usage side is located underneath, but also any other configuration of the mold part which forms the usage side would lead to the effect according to the invention. By choosing the particle size and the proportion of filler particles in conjunction with the proportion of the bifunctional or multifunctional monomer or polymer, settling of the filler particles caused by gravitation is largely avoided. Unnecessary, a specific proportion of a substance which prevents settling of the filler particles, in particular a thixotropy agent, is added. The crosslinking agent is preferable mixed with the binder solution directly and is uniformly distributed in it. Curing of the reaction mixture by polymerization of the binder solution takes place preferably in a mold, and especially in the production of three-dimensional molded bodies it can be a closed mold. Simple two-dimensional molded bodies such as for example tiles or surfaces can also generally be produced in open molds. Further features and advantages of the invention will be 'apparent from the dependent claims and the following description in which several embodiments of the invention are described in connection with the drawings. The features referred to in the claims and in the specification are essential for the invention individually or in any combination. WO 2006/048214 PCT/EP2005/011627 10 FIG. 1 shows some components of the reaction mixture in a schematic. FIG. 2 schematically shows the connection of quality of molded plastic bodies produced according to the invention depending on the proportion of the crosslinking agent, FTG. 3 shows in a perspective a generic molded plastic body, FIG. 4 shows in table form the composition of a total of five formulations, FIG. 5 shows in table form the results of the formulations of FIG. 4, and FIG. 6 shows in table form the results of the formulations with and without filler. FIG. 1 shows schematically some components of the reaction mixture 2, in particular the particulatc inorganic filler 3, the crosslinking agent 4 and binder solution 5 which is formed from a so-called syrup with monomer components 5a, for example methyl methacrylate, and polymer components 5b, for example polymethyl methacrylate. In the uncured state the reaction mixture 2 is of such low viscosity that it is castable, in particular can be produced by cast molding of the molded plastic bodies 1 according to the invention (FIG. 3). FIG. 2 schematically shows the connection of the quality of molded plastic bodies produced according to the invention depending on the proportion of the crosslinking agent 4 in % by weight relative to the proportion of monomer in the binder solution 5. On the basis of a value of 3% by weight which is known from the prior art, in particular the visual quality of the produced molded plastic bodies 1 decreases with an increasing proportion of crosslinking agent and reaches an undesirable minimum at approximately 6% by weight. Surprisingly, as the proportion of the crosslinking agent 4 continues to increase the quality increases again and exceeds the quality of known molded plastic bodies in many applications for values above 10% by weight. WO 2006/048214 PCT/EP2005/011 627 11 FIG. 3 shows in perspective a generic molded plastic body 1, in the illustrated case a built-in sink with double sinks. For production purposes closed casting molds are used to which the reaction mixture is added and then is cured by polymerization which is effected by supply of energy. Two- dimensional molded bodies such as for example tiles or surfaces basically can be produced analogously. FIG. 4 shows in table form the composition of five formulations, of which formulation 3 is according to the invention. Unless otherwise indicated, all percentages are percentages by weight relative to the reaction mixture. The proportions of polymer and monomer (methyl methacrylate) together yield 100% of the binder solution which has an approximately 30% proportion of the reaction mixture for the five formulations. The proportion of the binder solution from polymethyl methacrylate arid methyl methacrylate in the total reaction mixture in formulation (1) is 33.61%, in formulation (2) 28.61%, in formulation (3) 24.18%, in formulation (4) 29.28% and in formulation (5) 24.91%. The information pertaining to the crosslinking agent and peroxides relates conversely as percent by weight to the proportion of monomer in the binder solution which is formed from the polymer and methyl methacrylate. The information pertaining to the separating agent relates as percent by weight to the binder solution. In formulation 1 the filler is cristobalite flour with a proportion of 61.42% and crosslinking agent proportion of 2.64%. In formulation 2 the filler is natural colored silica sand with a particle stee from 0.05 to 0.3 mm, as sold by the DORFNER company under the trade name GEBA, with a proportion of 68.17% and a crosslinking agent proportion of 3.05%. WO 2006/048214 PCT7EP2005/011627 12 In formulation 3 the filler is natural colored silica sand with a particle size from 0.05 to 0.3 mm, as sold by the DORFNER company under the trade name GEBA with a proportion of 68.22% and a crosslinking agent proportion of 27.62%. In formulation 4 the filler is natural colored silica sand with a particle size from 0.05 to 0.3 mm, as sold by the DORFNER company under the trade name GEBA with a proportion of 68.17%. In formulation 4 no crosslinking agent is used. In formulation 5 the filler is composed of two different silica sands, specifically of a black- coated silica sand with a particle size between 0.1 and 0.6 mm with a proportion of 52.592% and of a natural colored silica sand with a particle size from 0.05 to 0.3 mm, as sold by the DORFNER company under the trade name GEBA with a proportion of 19.526% and a crosslinking agent proportion of 2.95%. Formulations 2, 3, and 4 have the same filler, GEBA, with an essentially identical proportion by weight of approximately 68%, formulation 2 having the conventional proportion of crosslinking agent, formulation 3 the proportion of crosslinking agent according to the invention and formulation 4 having no crosslinking agent in order to obtain comparison values for the results which can be achieved with formulation 3 according to the invention. Aside from the filler, formulations 2 and 5 are similar, in order to obtained comparison values for different fillers at conventional proportions of crosslinking agents. The reaction mixture 2, besides the binder solution 5 which for its part has monomer portions 5a, in particular methyl methacrylate, and polymer portions 5b, and the filler 3, consists of a series of loading materials, including the crosslinking agent 4, a so-called internal separating agent for improved release of the cured molded body from the mold, pigments for coloring, antisettling agents for homogenization of the fillers in the reaction mixture to be cured and peroxides for uniform controlled starting of polymerization. In this connection, except for the pigments and the WO 2006/048214 PCT/EP2005/011627 13 antisettling agents, the loading materials are added to the binder solution. The percentages for the crosslinking agent and the peroxides in the aforementioned formulations relate to the monomer. FIG. 5 shows in table form the results of the formulations of FIG. 4 with respect to important usage properties. This clearly indicates that formulation 3 according to the invention optimally combines the positive properties of formulations 1 and 2 with one another. The hot pot test (HTT) based on standard EN 13310 upon visual inspection does not show any detectable damage. The corresponding applies to the water vapor test (WDT) based on standard EN 13310. In the hot/cold cycle test based on standard EN 13310 there is no visible brightening and no perceptible roughening. Decorative cracks as a result of hot/cold cycles (HKZ) at the most appear slightly. The soiling test (AST) does not reveal any dirt residue; this confirms the good result relating to roughening after the hot/cold cycle test. The DE value of 0.46 corresponds to an only very slight color change. Finally the Taber abrasion test (TAT) according to DIN 53799 [DIN - German Industrial Standard] also yields a very low and thus good value; the level of the numerical value corresponds to the weight loss by abrasion per 100 revolutions. Formulation 1 yields a single-color black molded body with a smooth surface. Formulation 2 yields a molded body with a granite appearance with a black ground shade. Formulation 3 yields a molded body with a novel surface in the color black. Formulation 3 yields a molded body with a smooth acrylic surface in the color black. Formulation 5 yields a molded body with granite appearance with a surface in the color black. One special feature of the molded body according to the invention consists in that the surface is very hard and thus has high scratch resistance. Moreover, especially smooth surfaces are formed, particularly when using fillers with an average and great grain size. WO 2006/048214 PCT/EP2005/011627 14 FIG. 6 shows in table form other results of the formulations of FIG. 4, this time relating to roughness before and after a scratch test and the Rockwell hardness. For hardness measurements sample pieces were produced without fillers, so that the hardness measurements are not adulterated by filler particles, but actually the hardness of the polymerized surface layer is determined. The hardness measurements were taken by means of a hardness measuring device ASTM 785-03 of ASTM International, 100 Barr Harbor Drive, in West Conshohocken, PA 19428-2959, USA. Here the Rockwell scale "£" was used which employs an indenter body ball with a diameter of 3.175 mm at a preliminary force of 10 kg and a main force of 100 kg. The measurements were taken according to a so-called "Procedure A" as is stated in the instruction "Standard Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials" of ASTM International for D-785-03. As a result of the hardness test, for formulation 3 according to the invention a very good value of 17.0 arises, conversely for formulation 2 with a proportion of crosslinking agent of 3.05% by weight the value is 1.0, and the sample piece according to formulation 4 without a proportion of the crosslinking agent with -30.0 has the lowest value. Within the framework of these tests the crosslinking agent was trimethylolpropane trimethacrylate (TRIM). FTG. 6 furthermore shows results of roughness measurements for determining the smoothness of the surface, For the measured parameters surface roughness Rt, maximum surface roughness Rmax and averaged surface roughness Rz, it holds that the measured values are smaller, the smoother the surface. The surface roughness Rt arises from the difference of a local maximum to a local minimum of a section of definable length of the measured sections. There are no standardized measurement conditions for this characteristic. The determination of the averaged surface roughness Rz and the maximum surface roughness Rmax was conversely carried out according to DIN 4768 or DIN EN ISO 11562, edition: 1998-09. The averaged surface roughness Rz is determined by averaging over five individual surface roughnesses so that the effect of outliers on the measured value is reduced. The maximum surface roughness Rmax is the greatest individual surface roughness within the overall measured distance, with a length which can be defined. WO 2006/048214 PCT/EP2005/011627 15 The roughness was measured after producing the sample piece as "roughness before the scratch test". Then for sample pieces of formulations 2,3 and 4 without a filler and in sample pieces of formulations 1 and 3 with a filler a scratch test was run, the pertinent scratching device corresponding to DIN 53799 Tl0 or DIN 13310, and the scratching diamond having a 90° conical ground surface with 90 urn edge diameter. In the sample pieces of formulations 2,3 and 4 without fillers there was minor roughness, as expected, before the scratching test. This smooth surface is however greatly roughened by the scratch test for formulations 2 and 4 with a conventional proportion of crosslinking agent or without crosslinking agents, as follows from the high numerical values for parameters Rt, Rmax and Rz of more than 20. Conversely the sample piece according to formulation 3 according to the invention shows only relatively little roughening by the scratching test with measured values for Rt, Rmax and Rz of under 10 each. A corresponding result is also shown by the sample pieces of formulations 1 and 3 with fillers. Here for the sample piece of formulation 1 before the scratch test even smaller measured values for roughness arise, only because in formulation 1 a much finer filler is used, see FIG. 4. Formulation 3 according to the invention before the scratch test likewise yields very smooth surfaces with results for Rt, Rmax and Rz of a maximum 2, conversely formulations 2 and 4 which are comparable with respect to the filler used with a conventional proportion of crosslinking agent or without a portion of crosslinking agent have much higher roughness values of approximately 10 or more, for which reason a comparable scratch test could no longer be conducted, and accordingly in FIG. 6 with respect to formulations 2 and 4 no measurement results for roughness after the scratch test are listed. It is striking here that proceeding from formulation 4 (no crosslinking agent) when the proportion of the crosslinking agent increases (formulation 2), the roughness first increases. It is quite surprising that as the proportion of the crosslinking agent continues to increase (formulation 3), the roughness all at once decreases drastically and thus much smoother surfaces are formed. This 2006/048214 PCT/EP2005/011627 16 result corresponds to that behavior of the quality shown schematically in FIG. 2 over the proportion of the crosslinking agent Formulation 3 according to the invention after the scratch test also shows low roughness values of less than 3, conversely the comparison formulation 1 has much greater roughness in spite of the much finer filler used there. FIGS. 7a and 7b show the topography of the molded bodies which have been produced in cross section, FIG, 7a for a molded body 10 according to the prior art and FIG. 7b for a molded body 1 according to the invention. For the known molded body 10 shrinkage of the surface 16 of the molded body 10 away from the casting mold surface 20, as a result of shrinkage of the binder matrix and thus molding of the filler particles 13 to the surface of the molded body 10, and for this reason protrusion of the filler particles 13, occur. A topography forms on the surface 16 which is not decisively determined by the casting mold surface 20 and which is dependent on the size of the filler particles 13 and the distance of two adjacent filler particles 13. for fillers on the order of 100 and 200 urn the maximum height difference 18 on the section between the two adjacent filler particles 13 can be up to 13 um or up to 7% of the distance between the adjacent filler particles. For otherwise identical molded bodies 1 according to the invention which however have a high proportion of the crosslinking agent (FIG. 7b), this maximum height difference 18 on the distance between two adjacent filler particles 4 is less than 2 urn or less than 1% of the distance between the adjacent filler particles; this results in perfect reproduction of the casting mold surface 20. WO 2006/0482J4 PCT/EP2005/OH627 17 Claims 1. Molded plastic body (1) which is produced from a cured reaction mixture (2), the reaction mixture (2) in the uncured state being castable and having an inorganic paniculate filler (3) with a proportion of 50 to 90% by weight relative to the reaction mixture (2), a crosslinking agent (4), and a binder solution (5) with a proportion from 10 to 50% by weight relative to the reaction mixture (2), the binder solution (5) having a monomer and a polymer dissolved therein, characterized in that the proportion of the crosslinking agent (4) which has been mixed with the binder solution (5) is more than 10% by weight relative to the proportion of the monomer in the binder solution (5). 2. The molded plastic body (1) according to claim I, wherein the proportion ofuhe crosslinking agent (4) is more than 12% by weight, relative to the proportion of monomer in the binder solution (5), preferably more than 15% by weight, and in particular between 20 and 30% by weight. 3. The molded plastic body (1) according to claim 1 or 2, wherein the crosslinking agent (4) is preferably a bifiinctional or multifunctional monomer or polymer, in particular a bifunctional or multifunctional acrylate or polyacrylate, preferably ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, or butane diol dimethacrylate. 4. The molded plastic body (1) according to one of claims 1 to 3, wherein the crosslinking agent (4) polymerizes more quickly than the polymerizable binder solution. 5. The molded plastic body (1) according to one of claims 1 to 4, wherein the crosslinking agent (4) is a combination of two or more bifunctional or multifunctional monomers or polymers, in particular a combination of two more bifunctional or multifunctional acrylates orpolyacrylates. WO 2006/048214 PCT/EP2005/011627 18 6. The molded plastic body (1) according to one of claims 1 to 5, wherein the crosslinking agent (4) is uniformly distributed in the reaction mixture (2), in particular wherein the crosslinking agent (4) is uniformly distributed in the binder solution (5). 7. The molded plastic body (1) according to one of claims 1 to 6, wherein the proportion of the binder solution (5) is between 10 and 45% by weight, in particular between 15 and 40% by weight and preferably between 20 and 35% by weight, each relative to the reaction mixture (2). 8. The molded plastic body (1) according to one of claims 1 to 7, wherein the ratio of the proportions by weight of the polymer to the monomer in the binder solution (5) is between 1:1 and 1:10, in particular between 1:2 and 1:7, and preferably between 1:3 and 1:5. 9. The molded plastic body (1) according to one of claims 1 to 8, wherein the binder solution (5) has a mixture of methyl methacrylate and polymethyl methacrylate. 10. The molded plastic body (1) according to one of claims 1 to 9, wherein the proportion of the paniculate inorganic filler (3) is between 55 and 85% by weight, in particular between 60 and 80% by weight and preferably between 65 and 75% by weight, each relative to the reaction mixture (2). 11. The molded plastic body (1) according to one of claims 1 to 10, wherein the particulate inorganic filler (3) is mineral, in particular crystalline. 12. The molded plastic body (1) according to one of claims 1 to 11, wherein more than 90% by weight of the particulate inorganic filler (3), in particular more than 95% by weight, each relative to the entire filler (3), has a grain size between 0.05 and 2 mm, in particular between 0.05 and 1.0 mm, and preferably between 0.05 and 0.3 mm. WO 2006/048214 PCT/EP2005/011627 19 13. The molded plastic body (1) according to one of claims 1 to 12, wherein the reaction mixture (2) moreover has a substance which prevents settling of filler particles (3), for example highly dispersed silicic acid. 14. The molded plastic body (1) according to one of claims 1 to 13, wherein the reaction mixture (2) moreover has dye pigments. 15. The molded plastic body (1) according to one of claims 1 to 14, wherein the reaction mixture (2) moreover has glossy particles, in particular glossy particles which do not have their own color, for example coated mica. 16. The molded plastic body (1) according to one of claims 1 to 15, wherein the filler particles (3) after polymerization on at least one surface of the molded body (1) is coated with a closed layer of polymerized binder solution (5). 17. The molded plastic body (1) according to one of claims I to 16, wherein the molded body (1) has a three-dimensional shape, for example a sink or a shower tray or bathtub, and wherein the reaction mixture (2) is cured in a mold. 18. The molded plastic body (1) according to one of claims 1 to 16, wherein the molded body (1) has an essentially two-dimensional shape, for example a tile or a surface, and wherein the reaction mixture (2) is cured in a mold. 19. Process for producing a molded plastic body (1) by curing a reaction mixture (2) which is castable in the uncured state and has an inorganic particulate filler (3) with a proportion of 50 to 90% by weight relative to the reaction mixture (2), and a binder solution (5) with a proportion from 10 to 50% by weight relative to the reaction mixture (2), the binder solution WO 2006/048214 PCT/EP200S/011627 20 (5) having a monomer and a polymer dissolved therein, wherein at least 10% by weight of a crosslinking agent (4) relative to the proportion of the monomer in the binder solution (5) are mixed into the binder solution (5). 20. The process according to claim 19, wherein the reaction mixture (2) is cured by polymerization of the binder solution (5). The invention relates o a molded plastic body (1) which is produced from a cured reaction mixture (2). Said reaction mixture (2) is pourable in the non-cured state and comprises 50 to 90% by weight, based on the reaction mixture (2), of an inorganic particulate filler (3), a cross-linking agent (4), and 10 to 50% by weight, based on the reaction mixture (2), of a binder solution (5). Said binder solution (5) comprises a monomer and a polymer dissolved therein. The inventive molded plastic body is characterized in that the percentage of the cross-linking agent (4) admixed to the binder solution (5) is more than 10% by weight based on the percentage of the monomer in the binder solution (5). The invention also relates to a method for producing the molded plastic body.

Full Text

WO 2006/048214 PCT/EP2005/011627
1
Schock GmbH
Gmiinder Strasse 65, D-73614 Schomdorf
Molded Plastic Body and Method for Producing the Same
The invention relates to a molded plastic body according to the preamble of claim 1 and a
method for producing a molded plastic body according to the preamble of the independent claim.
Generic molded bodies are used for example in the kitchen and bathroom, in particular as
sinks, working surfaces, shower trays or the like. In these applications it is especially important that
the molded bodies can be easily and thoroughly cleaned, and have high resistivity to mechanical and
thermal loads and especially to cyclic thermal loads in conjunction with water or water vapor.
DE 38 32 351 Al discloses molded plastic bodies according to the preamble of claim 1.
Matched to the mass of the monomer in the binder solution, in the prior art a so-called crosslinking
agent is added which causes three-dimensional crosslinking of the polymer chains among one
another and thus increases the hardness and solvent resistance of the molded body which has been
produced. The upper limit of the proportion of crosslinking agent is approximately 4% by weight
relative to the monomer proportion.

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A higher proportion of the crosslinking agent, depending on the particle size of the inorganic
particulate filler, leads to different results which are however undesirable. If for example the
proportion of crosslinking agent is increased when using a filler with a very small particle size, this
leads to the molded bodies tearing in the course of shaping polymerization. For coarser fillers
conversely an increase of the proportion of crosslinking agent leads to much more visible, in
particular white regions on the surface or directly under the surface, with a distribution which is
moreover irregular, and the associated molded body does not meet the quality requirements imposed
on appearance.
DE 199 49 461 Al discloses a curable casting mass which contains a proportion of 2.5% by
weight of the crosslinking agent (relative to the monomer content of the binder solution) in the
binder solution formed from the monomer (MMA) and polymer (PMMA). Tn some of the described
embodiments another crosslinking agent which is different from the crosslinking agent in the binder
solution is not added to the binder solution, but to a dye pigment dispersion. The molded parts
produced accordingly do not have the properties which can be achieved by this invention, especially
with respect to attainable smoothness of the surface and the outstanding cleanability which can be
achieved thereby.
DE 195 21 638 Al discloses a process for producing highly-filled plastics with a sparkle
effect, with a filler suspension with a content of crosslinking monomers given at preferably 0.1 to
5% by weight relative to the monomer content.
JP 09 067497 A and JP 63 068655 A likewise disclose reaction mixtures which contain
crosslinking agents and which however also are not castable in the uncured state.
The object of the invention is to make available a generic molded plastic body and the
pertinent production process which overcome the disadvantages of the prior art. In particular the
molded body should have good usage properties, especially good care properties and high resistance

WO 2006/048214 PCT/EP2005/011627
3
to mechanical and thermal loads, and high visual quality. The pertinent production process should
easily and economically yield molded bodies of high mechanical and visual quality.
This object is achieved by the molded body defined in claim 1 and by the production
process defined in the independent claim. Special embodiments of the invention are defined in the
dependent claims.
In a molded plastic body which is produced from a cured reaction mixture, the castable
reaction mixture in the uncured state having an inorganic particulate filler with a portion of 50 to
90% by weight relative to the reaction mixture, a crosslinking agent, and a binder solution with a
proportion from 10 to 50% by weight relative to the reaction mixture, the binder solution having a
monomer and a polymer dissolved therein, the object is achieved in that the proportion of the
crosslinking agent is more than 10% by weight relative to the proportion of the monomer in the
binder solution. The molded body is produced preferably in a casting mold.
It is quite surprising that on the basis of aproportion of the crosslinking agent of
approximately 3% by weight relative to the monomer portion, upon an increase especially the visual
properties of the molded bodies produced are first degraded in order to again distinctly improve
when the proportion is increased further. Especially for an increase beyond 10% by weight, molded
bodies are surprisingly obtained which with respect to wear resistance, scratch resistance and ease
of cleaning combine an optimum of these properties. According to the invention a uniform
distribution of small polymer regions is achieved which no longer exhibit the negative properties of
spot formation and still adequately stabilize the molded body which has been produced in order to
prevent tearing during and after forming. Moreover a closed surface is formed which in addition
also combines haptically distinct advantages over molded bodies from the prior art and a resistant
surface with high visual appeal. The surface has improved resistance to falling objects and/or higher
scratch resistance, and is also more resistant to hot surfaces.

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The attainable usage properties also depend on the grain size of the filler used. Fillers with a
grain size less than 0.05 mm can be referred to as fine fillers for many applications. When using
these fine fillers the surface is generally smooth and can be especially easily cleaned. However the
visibility of scratches is increased, in a hot pot test dulling can occur and the abrasion resistance is
less compared to molded bodies with coarser fillers. When using coarser filler there is conversely
generally higher resistivity to mechanical and thermal stresses, but brightening in hot/cold cycle test
and in the water vapor test can occur, for example under the action of hot water. Moreover
roughened areas can occur in the region of the sink bottom. Ease of cleaning of molded bodies
produced in this way is generally less. Nor does a combination of fine and coarse fillers lead directly
to an optimum result.
Both for fine and also coarse fillers however a further improvement of usage properties can
be achieved when the proportion of the crosslinldng agent is more than 10% by weight, preferably
more than 20 and in particular between 20 and 30% by weight, each relative to the proportion of
monomer in the binder solution. Preferably a crosslinking agent is used which polymerizes more
quickly than the other polymerizable binder solution. In this way an especially hard surface with
correspondingly good usage properties is produced. The crosslinking agent is preferably a
bifunctional or multifunctional monomer or polymer, in particular a bifunctional or multifunctional
acrylatc or methacrylate, such as for example ethylene glycol dimethacrylate or trimei:hylolpropane
trimethacrylate. Another possible crosslinking agent is pentaerythritol triacrylate or pentaerythritol
tetraacrylate or glycerin dimethacrylate. Research has shown that the crosslinking agent bisphenol-
A-ethoxylate(2)dimethacrylate in spite of a proportion of binder solution which is high according to
the invention does not deliver the desired results, for which reason in one preferred embodiment of
the invention this crosslinking agent is not suited, but other crosslinldng agents are preferred, in
particular trimethylol propane trimethacrylate or one of the aforementioned crosslinking agents. It
can also be advantageous to use a combination of two or more such crosslinking agents. The
overall designation acrylate can thus comprise both acrylates and also methacrylates.

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The proportion of the binder solution is between 10 and 45%, in particular between 15 and
40%, and preferably between 20 and 35% by weight, each relative to the reaction mixture. At these
percentages the crosslinking agent with its proportion which is high according to the invention is not
attributed to the binder solution. Monomers can be in particular styrene, acrylic acid or methacrylic
acid or its esters. In one special embodiment the binder solution has a mixture of methyl
methacrylate and polymethyl methacrylate, or a mixture of methyl methacrylate and a polymer, in
particular a mixture of methyl methacrylate and a homopolymer or copolymer of methyl
methacrylate, the copolymer preferably containing the comonomer ethylmethacrylate or butyl
methacrylate.
The ratio of the proportions by weight of the polymer to the monomer in the binder solution
is between 1:1 and 1:10, in particular between 1:2 and 1:7 and preferably between 1:3 and 1:5. As a
rule, the size of the filler particles used and the required proportion of the binder solution in
particular interact with one another such that when the proportion is increased coarser filler particles
of the proportion of binder solution tend to be able to be reduced.
The proportion of particulate inorganic filler is preferably between 55 and 85% by weight,
in particular between 60 and 80% by weight and preferably between 65 and 75% by weight, each
relative to the reaction mixture. In this case it is preferably a mineral inorganic filler, in particular a
crystalline filler such as for example silica sand.
Preferably the filler particles have a Mohs hardness of more than 5, in particular more than 6
and preferably approximately 7. This applies in any case to the overwhelming proportion of the
filler particles used. For technical and economic reasons the use of silicon dioxide with a Mohs
hardness of approximately 7 is preferred. Alternatively or in addition also other and in particular
harder filler particles can be used which are obtained naturally or synthetically. Examples here
include the corresponding glass, silicon carbide, aluminum oxide, or carbon in the diamond
modification.

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With respect to the hard layer near the surface, due to the high proportion of crosslinking
agent comparatively soft fillers with a Mohs hardness of less than 5 are possible, especially those
with a Mohs hardness of 3 to 4, such as for example calcium carbonate or the like.
Preferably use is made of naturally obtained silica sands. Especially those silica sands are
advantageous which are of high chemical purity, in particular with a low content of iron oxide, and
moreover which occur with a very narrow particle size range, for example between 0.05 and 0.3
mm, with a predominant mass proportion between 0.1 mm and 0.2 mm. These silica sands are
offered for example by the DORFNER company under the trade name GEBA, see
http://wvvw.dorfher.de. The reaction mixture cures with unswollen filler particles and in the uncured
state cannot be cast, so that all the crosslinking agent which has been added to the binder solution is
available for crosslinking of the binder solution.
Preferably the reaction mixture moreover has a substance which prevents settling of filler
particles, in particular a thixotroping agent. In this way warping of the polymerized molded body
will be prevented. The proportion of the substance which prevents settling of filler particles is less
than 1% by weight, relative to the reaction mixture, in particular less than 0.5% by weight, and
preferably approximately 0.15% by weight.
fn one special embodiment of the invention the reaction mixture moreover has dye
pigments. In particular the ease of cleaning of the molded bodies can thus be improved for example
in that in the entry areas of public buildings due to the coloring of the molded bodies dirt is not
overly conspicuous. Conversely, in areas with increased hygiene requirements, such as for example
hospitals or swimming pools, dirt can be clearly visible due to the coloring of the molded plastic
bodies.
The dye pigments can be uniformly or unevenly distributed depending on the application.
The dye pigments can also be prepared in a dye pigment dispersion which is later added to the

WO 2006/048214 PCT/EP2005/011627
binder solution and mixed with it. In one embodiment of the invention the dye pigment dispersion
does not contain any crosslinking agent, but the entire crosslinking agent is added to the binder
solution as long as it does not contain any dye pigments or in any event as long as it is not mixed
with a dye pigment dispersion. In addition to inorganic dye pigments, also organically based dye
pigments can be used, for example also an additional filler material in particle form with a size up to
a few millimeters which is formed by polymerization with other included inorganic filler particles.
Moreover by adding dye pigments it is possible to assign signal effects to the molded plastic bodies
which have been produced, for example molded plastic bodies that are colored as required, such as
for example tiles, in commercial areas can mark stop lines, walkways and driveways or the like, or
also a floor area with increased slip resistance can be delineated from a bordering floor area with
normal slip resistance in a recognizable manner.
Preferably the filler particles after polymerization on the surface of the usage side are coated
with a closed layer of polymerized mass. This improves especially the cleanability.
Studies of molded plastic bodies produced according to the invention have shown that a
high proportion of crosslinking agent in the binder solution does not effect shrinkage of the binder
matrix away from casting mold surface, but that rather the casting'mold surface is perfectly
reproduced by the produced molded body. The surface roughness which can be ascertained on the
produced molded body corresponds to the surface roughness of the casting mold surface and can be
set exactly, for example by working the casting mold surface in a specific manner in order to
prepare the surface topography desired on the molded body. In one embodiment the casting mold
surface is provided with a defined surface structure. The casting mold surface is shaped exactly. The
differences in contour of the casting mold surface along a curved path and the contour of the molded
body along the corresponding curved path are less than 5 μm, in particular less than 2 μm, and
preferably less than 1 μm.

WO 2006/048214 PCT/EP2005/0J1627
8
The high proportion of the crosslinking agent in the binder solution on the surface of the
molded body does not cause the protrusion of filler particles near the surface which is known in the
prior art and which is to some extent even required with respect to the desired hardness by the
shrinking back of the surrounding binder matrix which leads to a surface topography, but the
reaction mixture is tensioned in the cured state over the filler particles near the surface and thus
results in the extremely smooth surface. Thus for example for the molded bodies according to the
invention, on a section between two filler particles near the surface, aside from topographies of the
casting mold surface, at the filler content according to the invention, as is described for example in
the embodiment of formulation 3 explained below, the maximum "height difference" is less than 5
urn, in particular less than 3 urn and preferably less than 2 μrn, in particular less than 1% of the
length of the section.
The high degree of crosslinking is also confirmed by the low swelling, especially of the
layers of the produced molded body near the surface. Thus in a swelling test according to accepted
practice in polymer chemistry, especially when embedded in methyl methacrylate at atmospheric
pressure and room temperature for an interval of 20 hours with the visible side layer of the molded
plastic bodies according to the invention only a volumetric increase of less than 10% occurs, relative
to the initial volume, while in molded bodies from the prior art the volumetric increase under the
same conditions is generally more than 20%. The measurement of the volume increase for highly
filled materials, as in this case, yields greater relative increases compared to measurement of the
mass increase.
By preference glossy particles which induce a metallic gloss in the produced molded bodies
are added to the reaction mixture. In this connection in particular glossy particles are used which do
not have their own color, but for example due to coatings and the interference which occur thereby
cause color phenomena for the viewer. This is associated not only with outstanding visual
appearance, but also usage properties are improved. Suitably coated mica flakes are especially
preferred with respect to the layer material and/or layer thickness.

WO 2006/048214 ' PCT/EP2005/011627
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The invention also relates to a process for producing a molded plastic body as described
above, the process being characterized in that more than 10% by weight of a crosslinking agent
relative to the proportion of the monomer in the binder solution are added to the not yet cured
reaction mixture.
By preference the mold is filled with the reaction mixture as a dispersion and then the
polymerization process is started from the mold part which forms the usage side. Starting takes
place conventionally by heating up the pertinent mold part. The reaction mixture is polymerized
proceeding from the usage side to the opposite side of the molded body to be produced. Preferably
the mold part which forms the usage side is located underneath, but also any other configuration of
the mold part which forms the usage side would lead to the effect according to the invention.
By choosing the particle size and the proportion of filler particles in conjunction with the
proportion of the bifunctional or multifunctional monomer or polymer, settling of the filler particles
caused by gravitation is largely avoided. Unnecessary, a specific proportion of a substance which
prevents settling of the filler particles, in particular a thixotropy agent, is added.
The crosslinking agent is preferable mixed with the binder solution directly and is uniformly
distributed in it. Curing of the reaction mixture by polymerization of the binder solution takes place
preferably in a mold, and especially in the production of three-dimensional molded bodies it can be
a closed mold. Simple two-dimensional molded bodies such as for example tiles or surfaces can also
generally be produced in open molds.
Further features and advantages of the invention will be 'apparent from the dependent
claims and the following description in which several embodiments of the invention are
described in connection with the drawings. The features referred to in the claims and in the
specification are essential for the invention individually or in any combination.

WO 2006/048214 PCT/EP2005/011627
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FIG. 1 shows some components of the reaction mixture in a schematic.
FIG. 2 schematically shows the connection of quality of molded plastic bodies produced according
to the invention depending on the proportion of the crosslinking agent,
FTG. 3 shows in a perspective a generic molded plastic body,
FIG. 4 shows in table form the composition of a total of five formulations,
FIG. 5 shows in table form the results of the formulations of FIG. 4, and
FIG. 6 shows in table form the results of the formulations with and without filler.
FIG. 1 shows schematically some components of the reaction mixture 2, in particular the
particulatc inorganic filler 3, the crosslinking agent 4 and binder solution 5 which is formed from a
so-called syrup with monomer components 5a, for example methyl methacrylate, and polymer
components 5b, for example polymethyl methacrylate. In the uncured state the reaction mixture 2 is
of such low viscosity that it is castable, in particular can be produced by cast molding of the molded
plastic bodies 1 according to the invention (FIG. 3).
FIG. 2 schematically shows the connection of the quality of molded plastic bodies produced
according to the invention depending on the proportion of the crosslinking agent 4 in % by weight
relative to the proportion of monomer in the binder solution 5. On the basis of a value of 3% by
weight which is known from the prior art, in particular the visual quality of the produced molded
plastic bodies 1 decreases with an increasing proportion of crosslinking agent and reaches an
undesirable minimum at approximately 6% by weight. Surprisingly, as the proportion of the
crosslinking agent 4 continues to increase the quality increases again and exceeds the quality of
known molded plastic bodies in many applications for values above 10% by weight.

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FIG. 3 shows in perspective a generic molded plastic body 1, in the illustrated case a built-in
sink with double sinks. For production purposes closed casting molds are used to which the reaction
mixture is added and then is cured by polymerization which is effected by supply of energy. Two-
dimensional molded bodies such as for example tiles or surfaces basically can be produced
analogously.
FIG. 4 shows in table form the composition of five formulations, of which formulation 3 is
according to the invention.
Unless otherwise indicated, all percentages are percentages by weight relative to the reaction
mixture. The proportions of polymer and monomer (methyl methacrylate) together yield 100% of
the binder solution which has an approximately 30% proportion of the reaction mixture for the five
formulations. The proportion of the binder solution from polymethyl methacrylate arid methyl
methacrylate in the total reaction mixture in formulation (1) is 33.61%, in formulation (2) 28.61%,
in formulation (3) 24.18%, in formulation (4) 29.28% and in formulation (5) 24.91%. The
information pertaining to the crosslinking agent and peroxides relates conversely as percent by
weight to the proportion of monomer in the binder solution which is formed from the polymer and
methyl methacrylate. The information pertaining to the separating agent relates as percent by weight
to the binder solution.
In formulation 1 the filler is cristobalite flour with a proportion of 61.42% and crosslinking
agent proportion of 2.64%.
In formulation 2 the filler is natural colored silica sand with a particle stee from 0.05 to 0.3
mm, as sold by the DORFNER company under the trade name GEBA, with a proportion of 68.17%
and a crosslinking agent proportion of 3.05%.

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In formulation 3 the filler is natural colored silica sand with a particle size from 0.05 to 0.3
mm, as sold by the DORFNER company under the trade name GEBA with a proportion of 68.22%
and a crosslinking agent proportion of 27.62%.
In formulation 4 the filler is natural colored silica sand with a particle size from 0.05 to 0.3
mm, as sold by the DORFNER company under the trade name GEBA with a proportion of 68.17%.
In formulation 4 no crosslinking agent is used.
In formulation 5 the filler is composed of two different silica sands, specifically of a black-
coated silica sand with a particle size between 0.1 and 0.6 mm with a proportion of 52.592% and of
a natural colored silica sand with a particle size from 0.05 to 0.3 mm, as sold by the DORFNER
company under the trade name GEBA with a proportion of 19.526% and a crosslinking agent
proportion of 2.95%.
Formulations 2, 3, and 4 have the same filler, GEBA, with an essentially identical
proportion by weight of approximately 68%, formulation 2 having the conventional proportion of
crosslinking agent, formulation 3 the proportion of crosslinking agent according to the invention
and formulation 4 having no crosslinking agent in order to obtain comparison values for the results
which can be achieved with formulation 3 according to the invention. Aside from the filler,
formulations 2 and 5 are similar, in order to obtained comparison values for different fillers at
conventional proportions of crosslinking agents.
The reaction mixture 2, besides the binder solution 5 which for its part has monomer
portions 5a, in particular methyl methacrylate, and polymer portions 5b, and the filler 3, consists of
a series of loading materials, including the crosslinking agent 4, a so-called internal separating agent
for improved release of the cured molded body from the mold, pigments for coloring, antisettling
agents for homogenization of the fillers in the reaction mixture to be cured and peroxides for
uniform controlled starting of polymerization. In this connection, except for the pigments and the

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antisettling agents, the loading materials are added to the binder solution. The percentages for the
crosslinking agent and the peroxides in the aforementioned formulations relate to the monomer.
FIG. 5 shows in table form the results of the formulations of FIG. 4 with respect to
important usage properties.
This clearly indicates that formulation 3 according to the invention optimally combines the
positive properties of formulations 1 and 2 with one another. The hot pot test (HTT) based on
standard EN 13310 upon visual inspection does not show any detectable damage. The
corresponding applies to the water vapor test (WDT) based on standard EN 13310.
In the hot/cold cycle test based on standard EN 13310 there is no visible brightening and no
perceptible roughening. Decorative cracks as a result of hot/cold cycles (HKZ) at the most appear
slightly. The soiling test (AST) does not reveal any dirt residue; this confirms the good result
relating to roughening after the hot/cold cycle test. The DE value of 0.46 corresponds to an only
very slight color change. Finally the Taber abrasion test (TAT) according to DIN 53799 [DIN -
German Industrial Standard] also yields a very low and thus good value; the level of the numerical
value corresponds to the weight loss by abrasion per 100 revolutions.
Formulation 1 yields a single-color black molded body with a smooth surface. Formulation
2 yields a molded body with a granite appearance with a black ground shade. Formulation 3 yields a
molded body with a novel surface in the color black. Formulation 3 yields a molded body with a
smooth acrylic surface in the color black. Formulation 5 yields a molded body with granite
appearance with a surface in the color black.
One special feature of the molded body according to the invention consists in that the
surface is very hard and thus has high scratch resistance. Moreover, especially smooth surfaces are
formed, particularly when using fillers with an average and great grain size.

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FIG. 6 shows in table form other results of the formulations of FIG. 4, this time relating to
roughness before and after a scratch test and the Rockwell hardness. For hardness measurements
sample pieces were produced without fillers, so that the hardness measurements are not adulterated
by filler particles, but actually the hardness of the polymerized surface layer is determined. The
hardness measurements were taken by means of a hardness measuring device ASTM 785-03 of
ASTM International, 100 Barr Harbor Drive, in West Conshohocken, PA 19428-2959, USA. Here
the Rockwell scale "£" was used which employs an indenter body ball with a diameter of 3.175 mm
at a preliminary force of 10 kg and a main force of 100 kg. The measurements were taken according
to a so-called "Procedure A" as is stated in the instruction "Standard Test Method for Rockwell
Hardness of Plastics and Electrical Insulating Materials" of ASTM International for D-785-03.
As a result of the hardness test, for formulation 3 according to the invention a very good
value of 17.0 arises, conversely for formulation 2 with a proportion of crosslinking agent of 3.05%
by weight the value is 1.0, and the sample piece according to formulation 4 without a proportion of
the crosslinking agent with -30.0 has the lowest value. Within the framework of these tests the
crosslinking agent was trimethylolpropane trimethacrylate (TRIM).
FTG. 6 furthermore shows results of roughness measurements for determining the
smoothness of the surface, For the measured parameters surface roughness Rt, maximum surface
roughness Rmax and averaged surface roughness Rz, it holds that the measured values are smaller,
the smoother the surface. The surface roughness Rt arises from the difference of a local maximum
to a local minimum of a section of definable length of the measured sections. There are no
standardized measurement conditions for this characteristic. The determination of the averaged
surface roughness Rz and the maximum surface roughness Rmax was conversely carried out
according to DIN 4768 or DIN EN ISO 11562, edition: 1998-09. The averaged surface roughness
Rz is determined by averaging over five individual surface roughnesses so that the effect of outliers
on the measured value is reduced. The maximum surface roughness Rmax is the greatest individual
surface roughness within the overall measured distance, with a length which can be defined.

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The roughness was measured after producing the sample piece as "roughness before the
scratch test". Then for sample pieces of formulations 2,3 and 4 without a filler and in sample pieces
of formulations 1 and 3 with a filler a scratch test was run, the pertinent scratching device
corresponding to DIN 53799 Tl0 or DIN 13310, and the scratching diamond having a 90° conical
ground surface with 90 urn edge diameter. In the sample pieces of formulations 2,3 and 4 without
fillers there was minor roughness, as expected, before the scratching test. This smooth surface is
however greatly roughened by the scratch test for formulations 2 and 4 with a conventional
proportion of crosslinking agent or without crosslinking agents, as follows from the high numerical
values for parameters Rt, Rmax and Rz of more than 20. Conversely the sample piece according to
formulation 3 according to the invention shows only relatively little roughening by the scratching
test with measured values for Rt, Rmax and Rz of under 10 each.
A corresponding result is also shown by the sample pieces of formulations 1 and 3 with
fillers. Here for the sample piece of formulation 1 before the scratch test even smaller measured
values for roughness arise, only because in formulation 1 a much finer filler is used, see FIG. 4.
Formulation 3 according to the invention before the scratch test likewise yields very smooth
surfaces with results for Rt, Rmax and Rz of a maximum 2, conversely formulations 2 and 4 which
are comparable with respect to the filler used with a conventional proportion of crosslinking agent
or without a portion of crosslinking agent have much higher roughness values of approximately 10
or more, for which reason a comparable scratch test could no longer be conducted, and accordingly
in FIG. 6 with respect to formulations 2 and 4 no measurement results for roughness after the
scratch test are listed.
It is striking here that proceeding from formulation 4 (no crosslinking agent) when the
proportion of the crosslinking agent increases (formulation 2), the roughness first increases. It is
quite surprising that as the proportion of the crosslinking agent continues to increase (formulation
3), the roughness all at once decreases drastically and thus much smoother surfaces are formed. This

2006/048214 PCT/EP2005/011627
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result corresponds to that behavior of the quality shown schematically in FIG. 2 over the proportion
of the crosslinking agent
Formulation 3 according to the invention after the scratch test also shows low roughness
values of less than 3, conversely the comparison formulation 1 has much greater roughness in spite
of the much finer filler used there.
FIGS. 7a and 7b show the topography of the molded bodies which have been produced in
cross section, FIG, 7a for a molded body 10 according to the prior art and FIG. 7b for a molded
body 1 according to the invention. For the known molded body 10 shrinkage of the surface 16 of the
molded body 10 away from the casting mold surface 20, as a result of shrinkage of the binder
matrix and thus molding of the filler particles 13 to the surface of the molded body 10, and for this
reason protrusion of the filler particles 13, occur. A topography forms on the surface 16 which is not
decisively determined by the casting mold surface 20 and which is dependent on the size of the filler
particles 13 and the distance of two adjacent filler particles 13. for fillers on the order of 100 and
200 urn the maximum height difference 18 on the section between the two adjacent filler particles
13 can be up to 13 um or up to 7% of the distance between the adjacent filler particles. For
otherwise identical molded bodies 1 according to the invention which however have a high
proportion of the crosslinking agent (FIG. 7b), this maximum height difference 18 on the distance
between two adjacent filler particles 4 is less than 2 urn or less than 1% of the distance between the
adjacent filler particles; this results in perfect reproduction of the casting mold surface 20.

WO 2006/0482J4 PCT/EP2005/OH627
17
Claims
1. Molded plastic body (1) which is produced from a cured reaction mixture (2), the reaction
mixture (2) in the uncured state being castable and having an inorganic paniculate filler (3)
with a proportion of 50 to 90% by weight relative to the reaction mixture (2), a crosslinking
agent (4), and a binder solution (5) with a proportion from 10 to 50% by weight relative to
the reaction mixture (2), the binder solution (5) having a monomer and a polymer dissolved
therein, characterized in that the proportion of the crosslinking agent (4) which has been
mixed with the binder solution (5) is more than 10% by weight relative to the proportion of
the monomer in the binder solution (5).
2. The molded plastic body (1) according to claim I, wherein the proportion ofuhe crosslinking
agent (4) is more than 12% by weight, relative to the proportion of monomer in the binder
solution (5), preferably more than 15% by weight, and in particular between 20 and 30% by
weight.
3. The molded plastic body (1) according to claim 1 or 2, wherein the crosslinking agent (4) is
preferably a bifiinctional or multifunctional monomer or polymer, in particular a
bifunctional or multifunctional acrylate or polyacrylate, preferably ethylene glycol
dimethacrylate, trimethylolpropane trimethacrylate, or butane diol dimethacrylate.
4. The molded plastic body (1) according to one of claims 1 to 3, wherein the crosslinking
agent (4) polymerizes more quickly than the polymerizable binder solution.
5. The molded plastic body (1) according to one of claims 1 to 4, wherein the crosslinking
agent (4) is a combination of two or more bifunctional or multifunctional monomers or
polymers, in particular a combination of two more bifunctional or multifunctional acrylates
orpolyacrylates.

WO 2006/048214 PCT/EP2005/011627
18
6. The molded plastic body (1) according to one of claims 1 to 5, wherein the crosslinking
agent (4) is uniformly distributed in the reaction mixture (2), in particular wherein the
crosslinking agent (4) is uniformly distributed in the binder solution (5).
7. The molded plastic body (1) according to one of claims 1 to 6, wherein the proportion of the
binder solution (5) is between 10 and 45% by weight, in particular between 15 and 40% by
weight and preferably between 20 and 35% by weight, each relative to the reaction mixture
(2).
8. The molded plastic body (1) according to one of claims 1 to 7, wherein the ratio of the
proportions by weight of the polymer to the monomer in the binder solution (5) is between
1:1 and 1:10, in particular between 1:2 and 1:7, and preferably between 1:3 and 1:5.
9. The molded plastic body (1) according to one of claims 1 to 8, wherein the binder solution
(5) has a mixture of methyl methacrylate and polymethyl methacrylate.
10. The molded plastic body (1) according to one of claims 1 to 9, wherein the proportion of the
paniculate inorganic filler (3) is between 55 and 85% by weight, in particular between 60
and 80% by weight and preferably between 65 and 75% by weight, each relative to the
reaction mixture (2).
11. The molded plastic body (1) according to one of claims 1 to 10, wherein the particulate
inorganic filler (3) is mineral, in particular crystalline.
12. The molded plastic body (1) according to one of claims 1 to 11, wherein more than 90% by
weight of the particulate inorganic filler (3), in particular more than 95% by weight, each
relative to the entire filler (3), has a grain size between 0.05 and 2 mm, in particular between
0.05 and 1.0 mm, and preferably between 0.05 and 0.3 mm.

WO 2006/048214 PCT/EP2005/011627
19
13. The molded plastic body (1) according to one of claims 1 to 12, wherein the reaction
mixture (2) moreover has a substance which prevents settling of filler particles (3), for
example highly dispersed silicic acid.
14. The molded plastic body (1) according to one of claims 1 to 13, wherein the reaction
mixture (2) moreover has dye pigments.
15. The molded plastic body (1) according to one of claims 1 to 14, wherein the reaction
mixture (2) moreover has glossy particles, in particular glossy particles which do not have
their own color, for example coated mica.
16. The molded plastic body (1) according to one of claims 1 to 15, wherein the filler particles
(3) after polymerization on at least one surface of the molded body (1) is coated with a
closed layer of polymerized binder solution (5).
17. The molded plastic body (1) according to one of claims I to 16, wherein the molded body
(1) has a three-dimensional shape, for example a sink or a shower tray or bathtub, and
wherein the reaction mixture (2) is cured in a mold.
18. The molded plastic body (1) according to one of claims 1 to 16, wherein the molded body
(1) has an essentially two-dimensional shape, for example a tile or a surface, and wherein
the reaction mixture (2) is cured in a mold.
19. Process for producing a molded plastic body (1) by curing a reaction mixture (2) which is
castable in the uncured state and has an inorganic particulate filler (3) with a proportion of
50 to 90% by weight relative to the reaction mixture (2), and a binder solution (5) with a
proportion from 10 to 50% by weight relative to the reaction mixture (2), the binder solution

WO 2006/048214 PCT/EP200S/011627
20
(5) having a monomer and a polymer dissolved therein, wherein at least 10% by weight of a
crosslinking agent (4) relative to the proportion of the monomer in the binder solution (5)
are mixed into the binder solution (5).
20. The process according to claim 19, wherein the reaction mixture (2) is cured by
polymerization of the binder solution (5).

The invention relates o a molded plastic body (1) which is produced from a cured
reaction mixture (2). Said reaction mixture (2) is pourable in the non-cured state
and comprises 50 to 90% by weight, based on the reaction mixture (2), of an
inorganic particulate filler (3), a cross-linking agent (4), and 10 to 50% by weight,
based on the reaction mixture (2), of a binder solution (5). Said binder solution (5)
comprises a monomer and a polymer dissolved therein. The inventive molded
plastic body is characterized in that the percentage of the cross-linking agent (4)
admixed to the binder solution (5) is more than 10% by weight based on the
percentage of the monomer in the binder solution (5). The invention also relates to
a method for producing the molded plastic body.

Documents:

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Patent Number

270610

Indian Patent Application Number

1167/KOLNP/2007

PG Journal Number

02/2016

Publication Date

08-Jan-2016

Grant Date

01-Jan-2016

Date of Filing

04-Apr-2007

Name of Patentee

SCHOCK GMBH

Applicant Address

HOFBAUERSTRASSE 1, 94209 REGEN

Inventors:

#	Inventor's Name	Inventor's Address
1	PATERNOSTER, RUDOLF	LINDENSTRASSE 41, 94269 RINCHNACH
2	REICHENBERGER, ROLAND	POSCHETSRIEDERSTRASSE 24, 94209 REGEN
3	HOCK, KLAUS	ST. ANTON STRASSE 18, 94209 REGEN,

PCT International Classification Number

C08F 2/44

PCT International Application Number

PCT/EP2005/011627

PCT International Filing date

2005-10-31

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2004 055 365.3	2004-11-04	Germany