Lightweight Composite Material Having a Scratch-Resistant Surface and Method for the Production Thereof

Abstract

The present invention relates to a lightweight composite material having a binder and at least one first and at least one second filler, the first filler having a density of >2 kg/l and a Mohs hardness of >4 and the second filler having a bulk density of <2.5 kg/l. The concentration of the first filler in the composite material decreases starting from a first surface of the composite material in the direction of an opposite second surface of the composite material. In addition, the invention relates to a method for producing a composite material. This method includes the steps of providing a first filler which has a density of >2 kg/l and a Mohs hardness of >4, and providing a second filler which differs from the first filler and has a bulk density of <2.5 kg/l, and setting a concentration of the first filler in the resin that decreases in the vertical direction from a base surface of the casting mould by utilising the different mobilities of the filler particles in the resin.

Claims

1-15. (canceled)

16. A composite material comprising a binder and at least one first and at least one second filler, the first filler having a density of >2 kg/l and a Mohs hardness of >4 and the second filler having a bulk density of <2.5 kg/l, wherein the concentration of the first filler in the composite material decreases starting from a first surface of the composite material in the direction of an opposite second surface of the composite material.

17. The composite material according to claim 16, wherein the decrease in the concentration of the first filler in the composite material starting from the first surface of the composite material in the direction of the second surface is described by a continuous function.

18. The composite material according to claim 16, wherein the function is an exponential function having a base <1.

19. The composite material according to claim 16, wherein the increase in the concentration of the second filler in the composite material starting from the first surface of the composite material in the direction of the second surface of the composite material is described by a continuous function.

20. The composite material according to claim 16, wherein the function is an exponential function having a base >1.

21. The composite material according to claim 16, wherein particles of the first filler and the particles of the second filler differ in at least one property which allows a separation and/or an enrichment or a depletion within predetermined regions of the composite material before its hardening.

22. The composite material according to claim 16, wherein the distinguishing property is selected from a group comprising density, grain size (Sedi-Graph), morphology, and contact angle to the binder.

23. The composite material according to claim 16, wherein the concentration of the first filler in the composite material decreases along a height direction of the composite material, the composite material having an extension in the height direction of ≤10 cm.

24. The composite material according to claim 16, wherein the first and/or second filler(s) comprise(s) an isotropic granular material.

25. The composite material according to claim 16, wherein the binder is a viscous resin which has a viscosity of ≥100 mPa.Math.s and ≤5,000 mPa.Math.s.

26. The composite material according to claim 25, wherein the resin comprises an acrylic resin and/or a polyester resin and/or a PU resin.

27. The composite material according to claim 16, wherein a change in the coefficient of thermal expansion starting from the first surface of the composite material in the direction of the second surface of the composite material has a continuous course.

28. The composite material according to claim 16, wherein the first filler has a particle size (d50 SediGraph) of ≥01 μm and ≥500 μm.

29. The composite material according to claim 16, wherein particles of the first and/or the second filler have a surface coating which changes the visual appearance of the particle.

30. The composite material according to claim 29, wherein different particle fractions of the filler have surface coatings of the same colour or different colours and/or a surface coating which changes the light refraction and/or the reflection.

31. The composite material according to claim 16, wherein the binder contains a pigment which gives the binder a colour that is different from the particles of at least one filler.

32. A material comprising the composite material of claim 16, wherein the material is selected from a group comprising flooring, wall covering, sanitary product, wash basins or shower trays, furniture construction, kitchen sinks, work surface, and worktop.

33. A method for producing a composite material, comprising the steps of: providing a casting mould, providing a resin, providing a first filler which has a density of >2 kg/l and a Mohs hardness of >4, providing a second filler which differs from the first filler in at least one property and has a bulk density of <2.5 kg/l, setting a viscosity of the resin at which the mobility of particles of the first filler differs from the mobility of particles of the second filler in the resin, filling the provided substances into the casting mould, setting a concentration of the first filler in the resin that decreases in the vertical direction from a base surface of the casting mould by utilising the different mobility of the particles of the first filler and the mobility of the particles of the second filler, and subsequently hardening the resin to form a composite material.

34. The method for producing a composite material according to claim 33, wherein a surface coating which changes the visual appearance of the particles is applied to particles of the first and/or the second filler before being mixed with the resin.

35. The method for producing a composite material according to claim 33, wherein a pigment is added to the resin that gives the resin a colour which is different from the particles of at least one filler.

Description

[0069] Further advantages and embodiments can be found in the accompanying figures, in which:

[0070] FIG. 1 is a section through a composite material according to the invention in a first embodiment;

[0071] FIG. 2 is a section through a composite material according to the invention in a second embodiment;

[0072] FIG. 3 is a section through a composite material according to the invention in a third embodiment;

[0073] In FIG. 1-3, different embodiments of a composite material according to the invention are shown in each case. All embodiments contain dark-coloured sand as the first filler and pumice as the second filler. The binder is identical in each case.

[0074] In the embodiments of the composite material according to the invention shown in FIGS. 1 and 2, the first filler and the second filler as well as the binder are each identical. The composite materials shown in FIGS. 1 and 2 nevertheless differ in the course of the gradient by which the concentration of the first (darker) filler decreases with decreasing height. While the gel time of the binder was selected to be extremely short in the composite material shown in FIG. 1, the composite material shown in FIG. 2 is based on a mixture which had a long gel time of the binder. Due to the longer gel time, the mixture shown in FIG. 2 had a comparatively long time available for the enrichment or depletion of the particles of the first and second filler in specific regions of the composite material. Accordingly, the embodiment shown in FIG. 1 has an extremely flat gradient, while the gradient in the embodiment shown in FIG. 2 can be clearly seen.

[0075] By comparing the embodiments of the composite material according to the invention shown in FIGS. 1 and 2, the influence of the particle size on the steepness of the gradient can also be seen. The type of first and second fillers is identical (coloured sand), but the average particle size (d.sub.50 SediGraph) of the first fillers is different in the embodiments of the composite material according to the invention shown in FIGS. 1 and 2. The particles of the first fillers used in the embodiment shown in FIG. 3 have a larger particle size (d.sub.50 SediGraph) than those of the first fillers in the composite material shown in FIG. 2. In the case of the same gel time of the binder, the larger particle size results in an even steeper gradient in the decrease in the concentration of the particles of the first filler than in the embodiment shown in FIG. 2.

[0076] As can be seen from these figures, the gradient of the decrease in the concentration of the particles of the first filler can therefore be influenced not only by the selection of the various different fillers, but also by the viscosity of the mixture, the gel time and the grain size distribution of the first filler and can be set according to the specifications on each composite material.

[0077] The applicant reserves the right to claim all the features disclosed in the application documents as essential to the invention, provided that these are novel, individually or in combination, over the prior art.