Glass-ceramic article and enamel for the coating thereof

Patent metadata

Field	Value
Publication number	US-10155684-B2
Application number	US-201415029979-A
Country	US
Kind code	B2
Filing date	Oct 15, 2014
Priority date	Oct 18, 2013
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

A glass-ceramic article is at least partly coated with at least one layer of enamel, including a glass frit. The frit includes, expressed by weight, SiO 2 , 45-60%; Al 2 O 3 , 12-22%; B 2 O 3 , 12-22%; Li 2 O, 0-5%; Na 2 O, 0-2%; K 2 O, >2%; CaO, 0-4%; MgO, 0-4%; ZnO, 0-4%; BaO, 0-4%; ZrO 2 , 0-4%; and TiO 2 , 0-1%. The sum of oxides CaO+MgO+BaO+SrO+ZnO is at most 10%, preferably from 2 to 8%. A process can be used to obtain the article.

First claim

The invention claimed is:

1. A glass-ceramic article, at least partly coated with at least one layer of an enamel formed from a glass frit having the following composition, the proportions being expressed as weight percentages:
SiO 2 45-60%,
Al 2 O 3 12-22%,
B 2 O 3 12-22%,
Li 2 O 0-5%,
Na 2 O 0-2%
K 2 O >2%
CaO 0-4%,
MgO 0-4%,
ZnO 0-4%,
BaO 0-4%,
ZrO 2 0-4%,
TiO 2 0-1%,
the sum of the oxides CaO + MgO + BaO + SrO + ZnO moreover being less than or equal to 10%,
wherein the enamel provides an appearance that is merged with the glass-ceramic article on which it is coated or a contrast with respect to the remainder of the article depending on an angle of observation.

2. The glass-ceramic article as claimed in claim 1 , wherein the enamel comprises a pigment content of less than 5% by weight.

3. The glass-ceramic article of claim 1 , wherein the difference between the refractive index of the enamel and that of the glass-ceramic is less than 0.05.

4. The glass-ceramic article of claim 1 , having a softening point of less than 800° C.

5. The glass-ceramic article of claim 1 , wherein the difference between the lightness of the enamel and that of the glass-ceramic is less than 1.

6. The glass-ceramic article of claim 1 , wherein the brightness B of the enamel is greater than 50.

7. The glass-ceramic article of claim 1 , wherein the particle size distribution of the frit, and of optional pigments, in powder form is such that at least 90% by weight of the particles forming the powder have a diameter of less than 15 μm.

8. The glass-ceramic article of claim 1 , wherein the thickness of the enamel layer is from 2 μm to 4 μm.

9. The glass-ceramic article of claim 1 , wherein the article is formed from a glass-ceramic comprising less than 0.2% by weight of arsenic oxides.

10. The glass-ceramic article as claimed in claim 1 , wherein the enamel is devoid of pigment.

11. The glass-ceramic article of claim 1 , wherein the difference between the refractive index of the enamel and that of the glass-ceramic is less than 0.02.

12. The glass-ceramic article of claim 1 , wherein the brightness B of the enamel is greater than 60.

13. The glass-ceramic article of claim 1 , wherein the particle size distribution of the frit, and of the optional pigments, in powder form is such that at least 90% by weight of the particles forming the powder have a diameter of less than 4 μm.

14. The glass-ceramic article as claimed in claim 1 , wherein:
the difference between the lightness of the enamel and that of the glass-ceramic is less than 1;
the difference between the refractive index of the enamel and that of the glass-ceramic is less than 0.02;
the particle size distribution of the frit, and of optional pigments, in powder form is such that at least 90% by weight of the particles forming the powder have a diameter of 9-14 μm.

15. The glass-ceramic article of claim 14 , wherein the article is formed from a glass-ceramic comprising less than 0.2% by weight of arsenic oxides.

16. The glass-ceramic article of claim 14 , wherein the enamel is devoid of pigment.

17. The glass-ceramic article of claim 15 , wherein the enamel is devoid of pigment.

Assignees

• Eurokera

Inventors

• Lecomte Emmanuel
• Vilato Pablo

Classifications

• C03C17/04

  by fritting glass powder · CPC title

• C03C10/0027

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• H05B1/0266

  Cooktops · CPC title

• C03C10/00

  Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition · CPC title

• C04B41/5023

  Glass-ceramics (compositions of glass-ceramics C03C10/00) · CPC title