Substrate provided with a coating based on a glass flux, glass flux material, and method for coating a glass or glass ceramic substrate

1. A coated glass substrate, comprising:

a glass substrate having a coefficient of linear thermal expansion α at 20° C. to 300° C. of up to 5.5*10 −6 ; and

an opaque coating applied to the glass substrate as a glass flux material, the glass flux material including at least one pigment and a glass component, the glass component comprising:

SiO 2 58-65 mol %,

Al 2 O 3 2.5-3.6 mol %,

Bi 2 O 3 0.5-2 mol %, and

B 2 O 3 18-25 mol %,

with at least 2.5 mol % of at least one oxide of the group Li 2 O, Na 2 O and K 2 O, and

a ratio of alkali oxides to aluminum oxide ΣR 2 O/Al 2 O 3 that is greater than 2.1 and less than 6,

wherein the glass component has a softening temperature of less than 680° C.

2. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the ratio of alkali oxides to aluminum oxide ΣR 2 O/Al 2 O 3 is greater than 2.1 and less than 4.5.

3. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the glass component comprises:

Li 2 O 0-15 mol %,

Na 2 O 0-12 mol %, and

K 2 O 0-4 mol %.

4. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the glass component further comprises at least one material selected from the group consisting of up to 2 mol % of ZrO 2 , up to 2 mol % of TiO 2 , up to 3 mol % of alkaline earth metal oxides, up to 3 mol % of ZnO, and combinations thereof.

5. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the glass flux material is provided in form of a paste including a ground glass component, wherein the ground glass component has a particle size distribution with d 50 between 1.2 and 2.5 μm.

6. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the opaque coating has a thickness of more than 4 μm.

7. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the coated glass substrate is employed for a use selected from the group consisting of a bullet-proof glass laminate composite, a fireplace window, a pyrolysis oven window, a fire protection glazing, a lamp, and a pharmaceutical packaging.

8. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the glass component comprises at least 2.5 mol % of Li 2 O.

9. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the ΣR 2 O is at least 8 mol %.

10. The coated glass or glass ceramic substrate as claimed in claim 9 , wherein the ΣR 2 O is less than 18 mol %.

11. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the glass flux-based coating has, in L*a*b* color space, an L* value of more than 86 or less than 27, and an a* value of less than 0.05, and a b* value of less than 0.05.

12. The coated glass or glass ceramic substrate as claimed in claim 1 , wherein the glass flux-based coating is lead free.

13. A glass flux material for applying an opaque coating, comprising:

a paste of at least one pigment and a glass component, the glass component comprising:

SiO 2 58-65 mol %,

Al 2 O 3 2.5-3.6 mol %,

Bi 2 O 3 0.5-2 mol %, and

B 2 O 3 18-25 mol %,

with at least 2.5 mol % of at least one oxide of the group Li 2 O, Na 2 O, and K 2 O, and

a ratio of alkali oxides to aluminum oxide ΣR 2 O/Al 2 O 3 that is greater than 2.1 and less than 6,

wherein the glass component is ground and has a particle size distribution with a d50 between 1.2 and 2.5 mm, and

wherein the glass component has a softening temperature of less than 680° C.

14. The glass flux material as claimed in claim 13 , wherein the glass component comprises at least 2.5 mol % of Li 2 O.

15. A coated glass c, comprising:

a glass substrate having a coefficient of linear thermal expansion α at 20° C. to 300° C. of up to 5.5*10 −6 /K; and

a glass flux-based coating having a coefficient of linear thermal expansion α at 20° C. to 300° C. of less than 7*10 −6 /K, wherein the glass flux-based coating comprises at least one pigment and a glass component, the glass component comprising at least 2.5 mol % of Li 2 O, 2.5 to 3.6 mol % of Al 2 O 3 , 18 to 25 mol % of B 2 O 3 , and a ratio of alkali oxides to aluminum oxide ΣR 2 O/Al 2 O 3 that is greater than 2.1 and less than 6, and wherein the glass flux-based coating exhibits a transmittance of less than 1% in a wavelength range from 380 to 780 nm.

16. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the transmittance of the glass flux-based coating is less than 0.5%.

17. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the glass flux-based coating comprises pigments with a degree of volume filling from 10 to 60%.

18. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the substrate is curved, at least in portions thereof.

19. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the substrate is a multilayer composite.

20. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the glass flux-based coating has a thickness of more than 5 μm.

21. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the glass flux-based coating has, in L*a*b* color space, an L* value of more than 86 or less than 28.

22. The coated glass or glass ceramic substrate as claimed in claim 15 , wherein the glass flux-based coating has, in L*a*b* color space, an a* value and a b* value of less than 1.

23. A coated glass substrate, comprising:

a glass substrate having a coefficient of linear thermal expansion α at 20° C. to 300° C. of up to 5.5*10 31 6 /K; and

an opaque coating applied to the glass substrate as a glass flux material, the glass flux material including at least one pigment and a glass component, the glass component comprising:

SiO 2 58-65 mol %,

Al 2 O 3 2.5-3.6 mol %,

Bi 2 O 3 0.5-2 mol %,

B 2 O 3 18-25 mol %, and

at least 2.5 mol % of an alkali oxide selected from the group consisting of Li 2 O, Na 2 O, K 2 O, and any combinations thereof,

wherein the glass component comprises a ratio of the alkali oxide to aluminum oxide that is greater than 2.1 and less than 6, and

the glass component comprises a sum of alkali oxides that is at least 8 mol %.

24. The glass flux material as claimed in claim 23 , wherein the substrate is made of borosilicate glass.

25. A glass flux material for applying an opaque coating, comprising:

a paste of at least one pigment and a glass component, the glass component comprising:

SiO 2 58-65 mol %,

Al 2 O 3 2.5-3.6 mol %,

Bi 2 O 3 0.5-2 mol %,

B 2 O 3 18-25 mol %, and

with at least 2.5 mol % of at least one oxide of the group Li 2 O, Na 2 O, and K 2 O, and

a ratio of alkali oxides to aluminum oxide ΣR 2 O/Al 2 O 3 that is greater than 2.1 and less than 6,

wherein the glass component is ground and has a particle size distribution with a d50 between 1.2 and 2.5 μm, and

wherein Na 2 O is present in an amount that is less than 5 mol % and/or in an amount that is less than an amount of Al 2 O 3 .

26. The glass flux material as claimed in claim 25 , wherein Na 2 O is less than or equal to 1.3 mol %.