Composite material with decorative coating and method for producing same

Abstract

The invention relates to a method for producing a composite material with a decorative coating, wherein a porous layer that includes pigment particles is applied onto a glass or glass ceramic substrate. The porous layer is filled with a polymer.

Claims

1. A composite material, comprising a glass ceramic substrate with a composite layer disposed on the glass ceramic substrate, the composite layer having a predominantly inorganic skeleton that has first pigment particles, wherein the composite layer is porous having nanoscale pores filled with a polymer, wherein the polymer is a polysiloxane, wherein the polymer comprises second pigment particles, and wherein the second pigment particles are platelet-shaped and lie upon the composite layer as an additional layer.

2. The composite material as claimed in claim 1, wherein the composite layer has a closed porosity of less than 20%.

3. The composite material as claimed in claim 1, wherein the composite layer has a closed porosity of less than 5%.

4. The composite material as claimed in claim 1, wherein the composite layer has a degree of gloss of G1 according to EN ISO 2813 standard.

5. The composite material as claimed in claim 1, wherein the composite material is suitable for a use selected from the group consisting of a part of a cooktop, a fireplace window, and a part of an oven door.

6. The composite material as claimed in claim 1, wherein the predominantly inorganic skeleton comprises a sol-gel layer.

7. The composite material as claimed in claim 6, wherein the sol-gel layer comprises the first pigment particles and oxide particles.

8. The composite material as claimed in claim 7, wherein the oxide particles are nanoparticles.

9. The composite material as claimed in claim 7, wherein the oxide particles are SiO.sub.2 nanoparticles.

10. The composite material as claimed in claim 7, wherein the oxide particles have a fibrous and/or chain-like morphology.

11. The composite material as claimed in claim 1, wherein the nanoscale pores have a mean pore diameter of less than 5 nm.

12. The composite material as claimed in claim 1, wherein the nanoscale pores have a mean pore diameter of less than 10 nm.

13. The composite material as claimed in claim 1, wherein the nanoscale pores have a mean pore diameter between 1 and 200 nm.

14. The composite material as claimed in claim 1, wherein the nanoscale pores have a mean pore diameter between 0.5 and 500 nm.

15. The composite material as claimed in claim 1, wherein the nanoscale pores have a mean pore diameter between 5 and 100 nm.

16. The composite material as claimed in claim 1, wherein the polymer has a density from 1.3 to 2.2 g/cm.sup.3.

17. The composite material as claimed in claim 1, wherein the polymer has a density from 1.5 to 1.9 g/cm.sup.3.

18. The composite material as claimed in claim 1, further comprising a volume ratio of material of the predominantly inorganic skeleton that has the first pigment particles to material of the polymer in the composite layer is from 10 to 0.5.

19. The composite material as claimed in claim 18, wherein the volume ratio is from 3 to 1.5.

20. A composite material, comprising a glass ceramic substrate with a composite layer disposed on the glass ceramic substrate, the composite layer having a predominantly inorganic skeleton that has first pigment particles and has nanoscale pores and having a polymer layer on the predominantly inorganic skeleton so as to fill in the nanoscale pores, the polymer layer comprising second pigments particles, the polymer layer having a polymer with a density from 1.0 to 2.5 g/cm.sup.3, and the composite layer having a closed porosity of less than 20%.

21. A composite material, comprising a glass ceramic substrate with a composite layer disposed on the glass ceramic substrate, the composite layer having a predominantly inorganic skeleton that has pigment particles and has nanoscale pores and having a polysiloxane layer on the predominantly inorganic skeleton so as to fill in the nanoscale pores.

22. A composite material, comprising: a glass ceramic substrate; a composite layer disposed on the glass ceramic substrate, the composite layer having a predominantly inorganic skeleton that has first pigment particles, wherein the composite layer has nanoscale pores; and a sealing layer comprising a polymer and platelet-shaped second pigment particles, the polymer filling the nanoscale pores and extending above the composite layer such that a portion of the sealing layer above the composite layer does not contain any of the first pigment particles, the second pigment particles being in the portion and lying upon the composite layer.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention will now be explained in more detail by way of schematically illustrated exemplary embodiments and with reference to the drawings of FIGS. 1 to 6.

(2) For illustration purposes, FIG. 1 schematically shows a composite material 1 including a composite layer applied according to the invention. A composite layer applied on a glass ceramic substrate 2 consists of a porous layer that has been filled with a polymer layer.

(3) The composite layer comprises coloring pigment particles 3. At the same time, the pigment particles 3 are used to form a porous skeleton. For example a manganese-ferrite spinel having an average particle size of less than 100 nm can be used.

(4) Furthermore, the material of the first layer initially applied as a sol-gel layer comprises non-coloring filler particles, in the present exemplary embodiment filler particles 4 having a mean diameter between 15 and 150 nm. Further particles 5 are likewise non-coloring skeletal particles from a molecular sol-gel precursor, for example silicon oxide having a granular structure with a mean particle size of less than 5 nm from pyrolyzed and previously hydrolyzed hybrid polymers (e.g. GPTES, TEOS).

(5) Particles 3, 4, 5 of the initially applied layer are filled with a polymer material 6, in the present exemplary embodiment with a high-temperature resistant polysiloxane, so that a dense composite material 8 has been formed.

(6) In the exemplary embodiment illustrated, the polymer material 6 was applied in such a large amount that a sealing layer 9 was created above the composite material 8, which does not contain any filler particles 4, 5, nor pigment particles 3 of the material of the first porous layer.

(7) Rather, the polymer material 6 was mixed with comparatively large platelet-shaped pigments which lie upon the particles of the first layer as an additional layer. Thus, a sealing layer 9 has been formed.

(8) FIG. 2a and FIG. 2b show flow charts which illustrate the essential process steps of one exemplary embodiment of the invention.

(9) First, a glass ceramic substrate is provided.

(10) Then a pigmented sol-gel layer is applied.

(11) The sol-gel layer is dried or cured and is optionally (FIG. 2b) baked at a temperature above 350 C. thereby producing a partially nanoscale porous, partially inorganic skeleton that is infiltrable by the silicone paint.

(12) Then, a pigmented silicone paint is applied, and the layer composite so produced in which the silicone paint fills the nanoscale pores of the sol-gel layer is baked at a temperature of more than 300 C. It will be understood that this may involve removal of organic components, in particular from the sol-gel layer. However, the silicone paint used should exhibit temperature resistance for baking the layer composite.

(13) FIG. 3 shows a table with a composition of the sol-gel coating material used, in a simple embodiment and in preferred and more preferred embodiments.

(14) Firstly, the hybrid polymer paint comprises binder components including a sol-gel hydrolyzate and nanoparticles.

(15) As coloring components, inorganic pigments are added.

(16) Furthermore, the hybrid polymer paint comprises a high boiling solvent.

(17) Optionally, initiators, organic crosslinkers and additives may be added in the specified amount.

(18) FIG. 4 shows a scanning electron micrograph of an exemplary embodiment of a dried hybrid polymer layer which was applied as the first layer, but has not yet been infiltrated by a polymer.

(19) In particular due to nanoscale particles added, an infiltrable layer has been formed.

(20) FIG. 5 shows this layer after the application of a polysiloxane. The texture of the first layer is still clearly visible. The first layer has been infiltrated by the polysiloxane, a thick composite layer has been formed.

(21) FIG. 6 shows the composite layer of FIG. 5 after having been subjected to a thermal load of more than 500 C. The texture visible in FIG. 5 largely remained intact. Hence, the layer is thermally stable up to above 500 C.

(22) FIG. 7 shows the layer illustrated in FIG. 4 without silicone infiltration after a thermal treatment at 400 C.

(23) A porous layer without infiltrated silicone resin has been formed.

(24) Specifically, a composite material of the invention may be produced as follows:

EXAMPLE 1

(25) First, 4 mol of MPTES (methacryloxypropyltriethoxysilane) is hydrolyzed with 1 mol of TEOS and 2.3 g of H.sub.2O in which 0.344 g of p-toluenesulfonic acid has been dissolved. Subsequently, the solvent is removed from this mixture on a rotary evaporator to obtain the so-called hydrolyzate.

(26) 18 g of the hydrolyzate are then mixed with 55 g of a 35 mass % solution of chain-like SiO.sub.2 nanoparticles in diethylene glycol monoethyl ether. Subsequently, 30 g of a nanoscale (<100 nm) black pigment (manganese ferrite spinel) is added to this solution.

(27) The paint is homogeneously stirred using a dissolver disk.

(28) The paint is then printed onto a transparent glass ceramic using a 140-mesh screen and thereafter is dried at 170 C. for 1 hour. Thus, the component which later forms a nanoscale skeleton has now been applied.

(29) Then, a second layer with the infiltrating component is applied on the first layer, likewise by screen printing. For this purpose, a silicone paint based on a methyl/phenyl silicone resin diluted in xylene (REN 80 from Wacker) is used. The silicone paint was mixed with 22 mass % of mica-shaped pigments having a mean particle size of 15 m. A 77 mesh screen is used for the screen printing of the infiltrating component.

(30) Subsequently, the entire layer stack is baked at 380 C. for 1 hour.

(31) In this way, a glass ceramic substrate with a dense homogeneous composite layer covered by a pigmented silicone layer is produced.

EXAMPLE 2

(32) First, 4 mol of GPTES (glycidoxypropyltriethoxysilane) is hydrolyzed with 1 mol of TEOS and 2.3 g of H.sub.2O in which 0.344 g of p-toluenesulfonic acid has been dissolved. Then, the solvent is removed from this mixture on a rotary evaporator to obtain the so-called hydrolysate.

(33) 18 g of the hydrolyzate are then mixed with 55 g of a 35 mass % solution of chain-like SiO.sub.2 nanoparticles in diethylene glycol monoethyl ether. Subsequently, 30 g of a nanoscale (<100 nm) black pigment (manganese ferrite spinel) is added to this solution.

(34) The paint is homogeneously stirred using a dissolver disk.

(35) The paint is then printed onto a transparent glass ceramic using a 140-mesh screen and thereafter is dried at 170 C. for 1 hour, and the layer is baked at 400 C. Thus, the component which later forms the nanoscale skeleton has now been applied.

(36) Then, a second layer with the infiltrating component is applied on the first layer, likewise by screen printing. For this purpose, a silicone paint is used which is based on a methyl/phenyl silicone resin diluted in xylene (DC 805 from Dow Corning). The silicone paint was mixed with 30 mass % of mica-shaped pigments having a mean particle size of 15 m. A 77-mesh screen is used for the screen printing of the infiltrating component.

(37) Subsequently, the entire layer stack is baked at 420 C. for 1 hour.

(38) In this way, a glass-ceramic substrate with a dense homogeneous composite layer covered by a pigmented silicone layer is produced.

(39) The invention enabled to provide a method which permits to very easily apply heat-resistant decorative coatings of almost any color location on a glass ceramic substrate.