Thermally tempered glass element and use thereof

Patent metadata

Field	Value
Publication number	US-10494293-B2
Application number	US-201615360370-A
Country	US
Kind code	B2
Filing date	Nov 23, 2016
Priority date	Nov 26, 2015
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

A thermally tempered glass element is provided made of glass with two opposite faces that are under compressive stress of at least 40 MPa. The glass has a working point at which the glass has a viscosity of 104 dPa·s of at most 1350° C. The glass has a viscosity versus temperature profile and a coefficient of thermal expansion versus temperature profile of the glass are such that a variable (750° C.−T13)/(CTELiq−CTESol) has a value of at most 5*106 K2. The CTELiq is a coefficient of linear thermal expansion of the glass above a glass transition temperature Tg, the CTESol is a coefficient of linear thermal expansion of the glass in a temperature range from 20° C. to 300° C., and the T13 is a temperature at which the glass has a viscosity of 1013 dPa·s.

First claim

What is claimed is:

1. A thermally tempered glass element, comprising:
glass with two opposite faces that are under compressive stress of at least 40 MPa,
wherein the glass has a working point at which the glass has a viscosity of 10 4 dPa·s of at most 1350° C.,
wherein the glass has a viscosity versus temperature profile and a coefficient of thermal expansion versus temperature profile of the glass are such that a variable
(750° C.− T 13 )/(CTE Liq −CTE Sol )

has a value of at most 5*10 6 K 2 ,
wherein CTE Liq is a coefficient of linear thermal expansion of the glass above a glass transition temperature T g ,
wherein CTE sol is a coefficient of linear thermal expansion of the glass in a temperature range from 20° C. to 300° C.,
wherein T 13 is a temperature at which the glass has a viscosity of 10 13 dPa·s, and
wherein the glass has a composition, in percent by weight, comprising:

SiO 2
63-75,

Al 2 O 3
 8-21; and

B 2 O 3
 0-8.

2. The glass element as claimed in claim 1 , wherein the coefficient of linear thermal expansion CTE sol is in a range from 3.5*10 −6 K −1 to 6*10 −6 K −1 .

3. The glass element as claimed in claim 1 , wherein the coefficient of linear thermal expansion CTE Liq is in a range from 11*10 −6 K −1 to 45*10 −6 K −1 .

4. The glass element as claimed in claim 1 , wherein the glass has a density of at least 2.4 grams per cubic centimeter.

5. The glass element as claimed in claim 1 , wherein the glass has a chemical resistance H, S, L of at least 2, 3, 3 or better, the chemical resistance being defined as hydrolytic class H according to ISO 719, acid class S according to DIN 12116, and alkali class L according to ISO 695.

6. The glass element as claimed in claim 1 , further comprising a coating on at least one of the two opposite faces.

7. The glass element as claimed in claim 6 , wherein the coating is a glass flux-based coating.

8. The glass element as claimed in claim 6 , wherein the coating has a coefficient of thermal expansion, CTE Coat , is adapted to the coefficient of thermal expansion CTE sol of the glass so that an absolute value of a difference of thermal expansion coefficients, |ΔCTE|=|CTE Sol −CTE Coat |, is not more than 1 ppm/K.

9. The glass element as claimed in claim 8 , wherein the difference is not more than 0.5 ppm/K.

10. The glass element as claimed in claim 8 , wherein the difference is not more than 0.3 ppm/K.

11. The glass element as claimed in claim 1 , further comprising a thickness between the two faces that is between greater than or equal to 2 mm and less than or equal to 5 mm.

12. The glass element as claimed in claim 1 , further comprising a thickness between the two faces that is between greater than or equal to 3 mm and less than or equal to 5 mm.

13. The glass element as claimed in claim 1 , wherein the composition, in percent by weight, further comprises:

Li 2 O
0-5,

Na 2 O
 0-14,

K 2 O
0-5,

MgO
 0-12,

CaO
 0-18,

SrO
0-5,

TiO 2
      0-5, and

ZrO 2
0-9.

14. The glass element as claimed in claim 13 , wherein the composition further comprises one more elements selected from the group consisting of refining agents, coloring agents, trace impurities inevitably contained in raw materials, and any combinations thereof, and wherein the one or more elements amount to a total of less than 2 wt %.

15. The glass element as claimed in claim 1 , wherein the glass with two opposite faces is configured for a use selected from the group consisting of a door of a cooking chamber, a door of an electric oven, a door of an electric oven having a pyrolysis function, a cooking surface, a cover for a heating element, a cooking surface, a frying surface, a cover for a heating radiator, a grilling surface, a fireplace window, a carrier sheet, a furnace lining, a solar device, a pharmaceutical device, a medical device, a furnace lining for chemical or physical coating processes, a chemically resistant laboratory equipment, a substrate for high temperature applications, a substrate for extreme low temperature applications, a combustion furnace window, a heat shield for hot environment, a cover for a radiator, an IR radiator, an IR radiator appliance, a reflector, a floodlight, a projector, a video projector, a photocopier, thermo-mechanical load device, a night vision device, a wafer substrate, UV protection substrate, a housing component, an electronic device housing, a cover glass, a mobile phone cover glass, a laptop computer cover glass, a scanner cover glass, a facade panel, a fire protection glazing, and a ballistic protection component.

16. The glass element as claimed in claim 1 , wherein the composition is free of B 2 O 3 .

Assignees

• Schott Ag

Inventors

• Schwall Michael
• Mlx Christian
• Alkemper Jochen
• Thomas Peter

Classifications

• C03C3/097 Primary

  containing phosphorus, niobium or tantalum · CPC title

• C03C3/091

  containing aluminium · CPC title

• C03B27/00

  Tempering {or quenching} glass products · CPC title

• C03C3/087 Primary

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• C03C17/02

  with glass (C03C17/34, C03C17/44 take precedence) · CPC title