GLASS-CERAMIC ITEM

Abstract

The present invention relates to an article, especially a cooktop or a furniture element, comprising at least one substrate, such as a plate, made of glass-ceramic, said substrate being coated in at least one zone with a paint comprising at least: 1) a silicone resin comprising methyl and phenyl group(s), 2) a silicone resin comprising methyl group(s) and devoid of phenyl group(s), 3) one or more lamellar inorganic fillers with a thickness of less than 2 μm and with lateral dimensions, for at least 80% by weight of said fillers, of less than 10 μm, including talc and/or one or more carbonates, 4) one or more black pigments.

The present invention also relates to a process for obtaining said article.

Claims

1. An article, comprising at least one substrate made of glass-ceramic, said substrate being coated in at least one zone with a paint comprising at least: 1) a silicone resin comprising methyl and phenyl groups; 2) a silicone resin comprising methyl group(s) and devoid of phenyl group(s); 3) one or more lamellar inorganic fillers with a thickness of less than 2 μm and with lateral dimensions, for at least 80% by weight of said fillers, of less than 10 μm, comprising talc and/or one or more carbonates; and 4) one or more black pigments.

2. The article as claimed in claim 1, wherein the silicone resin(s) of said paint are devoid of one or more functional groups selected from the group consisting of: halogen, epoxy, polyester, alkenyl, vinyl, allyl, alkynyl, mercapto, thiol, and acrylic.

3. The article as claimed in claim 1 wherein said paint comprises, as silicone resins, at least 75% by weight of the silicone resin(s) comprising methyl and phenyl groups and the silicone resin(s) comprising methyl group(s) and devoid of phenyl group(s), and wherein said paint is devoid of silicone resins of alkyd type and/or of epoxy type and/or of polyester type.

4. The glass-ceramic article as claimed in claim 1, wherein a content of the silicone resin(s) is between 20% and 50% by weight of said paint.

5. The glass-ceramic article as claimed in claim 1, wherein a content of said lamellar fillers is from 5% to 20% by weight.

6. The glass-ceramic article as claimed in claim 1, wherein a content of pigment(s) is between 10% and 30%, and wherein at least 50% of the particles of pigments exhibit a size of less than 1 μm.

7. The glass-ceramic article as claimed in claim 1, wherein the thickness of the paint coating is between 20 and 40 μm.

8. The glass-ceramic article as claimed in claim 1, wherein the paint coating exhibits a lightness L* of less than 5.

9. A process for the manufacture of the article as claimed in claim 1, the process comprising: coating a glass-ceramic substrate in at least one zone with a paint comprising at least: 1) a silicone resin comprising methyl and phenyl group(s); 2) a silicone resin comprising methyl group(s) and devoid of phenyl group(s); 3) one or more lamellar inorganic fillers with a thickness of less than 2 μm and with lateral dimensions, for at least 80% by weight of said fillers, of less than 10 μm, including talc and/or one or more carbonates; and 4) one or more black pigments.

10. The process as claimed in claim 9, wherein the paint is applied by screen printing to the glass-ceramic substrate, and is fired at temperatures between 350 and 480° C. for from 40 to 60 min.

11. The article as claimed in claim 1, wherein the article is a cooktop or a furniture element.

12. The article as claimed in claim 1, wherein the silicone resin comprising the methyl and phenyl groups is at least one selected from the group consisting of one or more polyphenylmethylsiloxane resins and one or more polydiphenyldimethylsiloxane resins.

13. The article as claimed in claim 1, wherein the silicone resin comprising methyl group(s) and devoid of phenyl group(s) is at least one selected from the group consisting of one or more polymethylsiloxane resins and one or more polydimethylsiloxane resins.

14. The article as claimed in claim 1, wherein said paint comprises, as silicone resins, at least 80% by weight of the silicone resin(s) comprising methyl and phenyl groups and the silicone resin(s) comprising methyl group(s) and devoid of phenyl group(s), and wherein said paint is devoid of silicone resins of alkyd type and/or of epoxy type and/or of polyester type.

15. The article as claimed in claim 1, wherein said paint comprises, as silicone resins, 100% by weight of the silicone resin(s) comprising methyl and phenyl groups and the silicone resin(s) comprising methyl group(s) and devoid of phenyl group(s).

16. The glass-ceramic article as claimed in claim 5, wherein said lamellar fillers are devoid of mica particles.

17. The glass-ceramic article as claimed in claim 6, wherein at least 75% of the particles of pigments exhibit a size of less than 1 μm.

18. The glass-ceramic article as claimed in claim 6, wherein at least 90% of the particles of pigments exhibit a size of less than 1 μm.

19. The glass-ceramic article as claimed in claim 6, wherein 100% of the particles of pigments exhibit a size of less than 1 μm.

20. The process as claimed in claim 10, wherein the screen-printing screen employed has a number of yarns per cm of between 32 and 43 yarns per cm.

Description

EXAMPLE 1 ACCORDING TO THE INVENTION

[0055] The paint used is prepared by mixing: [0056] 15% by weight of silicone resin of methyl/phenyl type sold under the reference RSN-0249 by Dow Corning, [0057] 15% by weight of silicone resin of methyl type sold under the reference Bayer P850 by Bayer, [0058] 20% by weight of black pigments based on iron and manganese oxide, the size distribution of which is less than 0.5 μm, these pigments being sold under the reference PBk 26.77494 by Kremer, [0059] 18% by weight of (fillers in the form of) talc sold by Imerys, these talc particles being of lamellar shape and with a thickness of less than 2 pm and exhibiting a D80 of 9 μm, [0060] 1% by weight of dispersant of reference Disperbyk 103 from Byk, [0061] 1% by weight of air-release agent of reference Byketol OK from Byk, [0062] 30% by weight of solvent of naphtha type sold under the reference Solvesso 100 by Exxon.

[0063] The paint is subsequently applied by screen printing with a mesh of reference 32 (32 yarns per cm) to the substrate and then dried at 160° C. for 4 minutes. It is subsequently fired using a heat treatment from 350° C. to 450° C. for 45 minutes.

EXAMPLE 2 ACCORDING TO THE INVENTION

[0064] The paint used is prepared by mixing: [0065] 15% by weight of silicone resin of methyl/phenyl type sold under the reference Silres 604 by Wacker, [0066] 15% by weight of silicone resin of methyl type sold under the reference Bayer P850 by Bayer, [0067] 20% by weight of black pigments based on iron and manganese oxide, the size distribution of which is less than 0.5 μm, these pigments being sold under the reference PBk 26.77494 by Kremer, [0068] 18% by weight of (fillers in the form of) talc sold by Imerys, these talc particles being of lamellar shape and with a thickness of less than 2 μm and exhibiting a D80 of 9 μm, [0069] 1% by weight of dispersant of reference Disperbyk 103 from Byk, [0070] 1% by weight of air-release agent of reference Byketol OK from Byk, [0071] 30% by weight of solvent of naphtha type sold under the reference Solvesso 100 by Exxon.

[0072] The paint is subsequently applied by screen printing with a mesh of reference 32 to the substrate and then dried at 160° C. for 4 minutes. It is subsequently fired using a heat treatment from 350° C. to 450° C. for 45 minutes.

REFERENCE EXAMPLE 1 NOT IN ACCORDANCE WITH THE INVENTION

[0073] The paint used is prepared by mixing: [0074] 35% by weight of silicone resin of methyl/phenyl type sold under the reference RSN-0249 by Dow Corning, [0075] 25% by weight of black pigments based on copper, chromium and manganese oxide, the size distribution of which is 0.6 μm, these pigments being sold under the reference 42-303B by Tomatec, [0076] 8% by weight of (fillers in the form of) talc sold by Imerys, these talc particles being of lamellar shape and with a thickness of less than 2 μm and exhibiting a D80 of 8 μm, [0077] 1% by weight of dispersant of reference Disperbyk 103 from Byk, [0078] 1% by weight of air-release agent of reference Byketol OK from Byk, [0079] 30% by weight of solvent of naphtha type sold under the reference Solvesso 100 by Exxon.

[0080] The paint is subsequently applied by screen printing with a mesh of reference 32 to the substrate and then dried at 160° C. for 4 minutes. It is subsequently fired using a heat treatment from 350° C. to 450° C. for 45 minutes.

REFERENCE EXAMPLE 2 NOT IN ACCORDANCE WITH THE INVENTION

[0081] The paint used is prepared by mixing: [0082] 35% by weight of silicone resin of methyl type sold under the reference KR-220L by Shin-Etsu, [0083] 20% by weight of black pigments based on iron and manganese oxide, the size distribution of which is less than 0.5 μm, these pigments being sold under the reference PBk 26.77494 by Kremer, [0084] 13% by weight of (fillers in the form of) talc sold by Imerys, these talc particles being of lamellar shape and with a thickness of less than 2 μm and exhibiting a D80 of 8 μm, [0085] 1% by weight of dispersant of reference Disperbyk 103 from Byk, [0086] 1% by weight of air-release agent of reference Byketol OK from Byk, [0087] 30% by weight of solvent of naphtha type sold under the reference Solvesso 100 by Exxon.

[0088] The paint is subsequently applied by screen printing with a mesh of reference 32 to the substrate and then dried at 160° C. for 4 minutes. It is subsequently fired using a heat treatment from 350° C. to 450° C. for 45 minutes.

[0089] A sample of each glass-ceramic provided with each paint is subsequently placed on a heating element. The temperature measured at the coating is 260° C. (corresponding to the temperature experienced by the coating during the cooking of food of sausages type). Several heating cycles of 15 minutes at 260° C., followed by cooling down to ambient temperature, are subsequently carried out (total duration of each cycle of 20 minutes).

[0090] It is observed that the paint in the examples according to the invention withstands at least 1500 heating cycles without splitting or exhibiting cracks or delaminating, whereas, in the reference comparative examples, the paint splits/exhibits cracks and delaminates after 100 cycles. Furthermore, the paint of the examples according to the invention is particularly black (with an L*<5) and adheres well to the glass-ceramic substrate, the scratch tests according to the standards ISO 15184 and ISO 1518-1 respectively giving a resistance to a 2B pencil and a resistance to a force of at least 1N.

[0091] The articles, in particular plates, according to the invention can in particular be used with advantage to produce a novel range of cooktops for kitchen ranges or cooking surfaces or a novel range of work tables, consoles, central islands, and the like.