IP Library › Granted Patent US 8,802,581
Granted Patent B2
US 8,802,581 · App. 12/856,840 · Granted Aug 12, 2014

Zircon compatible glasses for down draw

Inventors: Matthew John Dejneka (Corning, NY); Adam James Ellison (Painted Post, NY); Benjamin Zain Hanson (Big Flats, NY)
Assignee: Corning Incorporated
C03C3/083C03C3/091C03C21/00C03C3/085
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Quick Facts
Patent No.
US 8,802,581
App. No.
12/856,840
Granted
Aug 12, 2014
Kind
B2
Abstract

A glass that is down-drawable and ion exchangeable. The glass has a temperature T 35kp at which the viscosity is 35 kilopoise. T 35kp is less than the breakdown temperature T breakdown of zircon.

Claims (35)

1. A glass comprising SiO 2 , Al 2 O 3 , and Na 2 O, wherein SiO 2 +B 2 O 3 ≧66 mol %, Al 2 O 3 ≧7 mol %, B 2 O 3 ≦6.27 mol %, Na 2 O≧9 mol %, B 2 O 3 +Na 2 O+K 2 O+MgO+CaO≧18 mol %, and CaO≦2 mol %, wherein the glass has a temperature T 35kp at which the glass has a viscosity of 35 kpoise and a zircon breakdown temperature T breakdown at which zircon breaks down to form ZrO 2 and SiO 2 , wherein T breakdown is greater than T 35kp wherein T margin =T breakdown −T 35kp , wherein T margin (° C.)=446.6−50.2[Al 2 O 3 ]+22.6[B 2 O 3 ]−4.4[Na 2 O]−3.9[K 2 O]−1.2[MgO+CaO] where concentrations [Al 2 O 3 ], [B 2 O 3 ], [Na 2 O], [K 2 O], [MgO], and [CaO] are expressed in mol %, and wherein T margin ≧0.

2. The glass of claim 1 , wherein the glass comprises: 61 mol %≦SiO 2 ≦75 mol %; 7 mol %≦Al 2 O 3 ≦15 mol %; 0 mol %≦B 2 O 3 ≦6.27 mol %; 9 mol %≦Na 2 O≦21 mol %; 0 mol %≦K 2 O≦4 mol %; 0 mol %≦MgO≦7 mol %; and 0 mol %≦CaO≦2 mol %.

3. The glass of claim 1 , wherein T margin =T breakdown −T 35kp , wherein T margin =610.6−41.0[Al 2 O 3 ]+9.9[B 2 O 3 ]−3.5[Na 2 O]−20.2[K 2 O]−25.6[MgO]+34.2[CaO] where concentrations [Al 2 O 3 ], [B 2 O 3 ], [Na 2 O], [K 2 O], [MgO], and [CaO] are expressed in mol %, and wherein T margin ≧0.

4. The glass of claim 1 , wherein the glass is down-drawable.

5. The glass of claim 1 , wherein the glass is fusion drawn into a glass sheet.

6. The glass of claim 5 , wherein the glass sheet has less than one inclusion of solid ZrO 2 per pound of glass sheet.

7. The glass of claim 1 , wherein B 2 O 3 +Na 2 O+K 2 O−Al 2 O 3 ≧0 mol %.

8. The glass of claim 1 , wherein the glass has a liquidus viscosity of greater than about 100 kpoise.

9. The glass of claim 1 , wherein the glass has a temperature at a viscosity of 350 poise, T 350 , of less than or equal to 1650° C.

10. The glass of claim 1 , wherein the glass is formed into one of a cover plate, a window, a casing, a display screen, and a touch panel of an electronic device.

11. The glass of claim 1 , wherein the glass is ion exchangeable.

12. The glass of claim 11 , wherein the glass is ion exchanged to form a compressive layer on at least one surface of the glass.

13. The glass of claim 12 , wherein the ion exchanged glass has a compressive stress of at least 350 MPa and a compressive depth of layer of at least 20 microns.

14. The glass of claim 12 , wherein the ion exchanged glass has a central tension of at least 10 MPa.

15. A glass, the glass comprising SiO 2 , Al 2 O 3 , and Na 2 O and having a temperature T 35kp at which the glass has a viscosity of 35 kpoise, wherein SiO 2 +B 2 O 3 ≧66 mol %, Al 2 O 3 ≧7 mol %, B 2 O 3 ≦6.27 mol %, Na 2 O≧9 mol %, B 2 O 3 +Na 2 O+K 2 O+MgO+CaO≧18 mol %, and CaO≦2 mol %, and having a temperature T breakdown at which zircon breaks down to form ZrO 2 and SiO 2 , wherein T breakdown is greater than T 35kp , wherein T margin =T breakdown −T 35kp , wherein T margin (° C.)=446.6−50.2[Al 2 O 3 ]+22.6[B 2 O 3 ]−4.4[Na 2 O]−3.9[K 2 O]−1.2[MgO+CaO] where concentrations [Al 2 O 3 ], [B 2 O 3 ], [Na 2 O], [K 2 O], [MgO], and [CaO] are expressed in mol %, and wherein T margin ≧0.

16. The glass of claim 15 , wherein the glass comprises: 61 mol %≦SiO 2 ≦75 mol %; 7 mol %≦Al 2 O 3 ≦15 mol %; 0 mol %≦B 2 O 3 ≦6.27 mol %; 9 mol %≦Na 2 O≦21 mol %; 0 mol %≦K 2 O≦4 mol %; 0 mol %≦MgO≦7 mol %; and 0 mol %≦CaO≦2 mol %.

17. The glass of claim 15 , wherein T margin =T breakdown −T 35kp , wherein T margin =610.6−41.0[Al 2 O 3 ]+9.9[B 2 O 3 ]−3.5[Na 2 O]−20.2[K 2 O]−25.6[MgO]+34.2[CaO] where concentrations [Al 2 O 3 ], [B 2 O 3 ], [Na 2 O], [K 2 O], [MgO], and [CaO] are expressed in mol %, and wherein T margin ≧0.

18. The glass of claim 15 , wherein the glass is down-drawable.

19. The glass of claim 15 , wherein the glass is fusion drawn into a glass sheet.

20. The glass of claim 19 , wherein the glass sheet has less than one inclusion of solid ZrO 2 per pound of glass sheet.

21. The glass of claim 15 , wherein B 2 O 3 +Na 2 O+K 2 O−Al 2 O 3 ≧0 mol %.

22. The glass of claim 15 , wherein the glass has a liquidus viscosity of greater than about 100 kpoise.

23. The glass of claim 15 , wherein the glass has a temperature at a viscosity of 350 poise, T 350 , of less than or equal to 1650° C.

24. The glass of claim 15 , wherein the glass is formed into one of a cover plate, a window, a casing, a display screen, and a touch panel of an electronic device.

25. The glass of claim 15 , wherein the glass is ion exchangeable.

26. The glass of claim 19 , wherein the glass is ion exchanged to form a compressive layer on at least one surface of the glass.

27. The glass of claim 26 , wherein the ion exchanged glass has a compressive stress of at least 350 MPa and a compressive depth of layer of at least 20 microns.

28. The glass of claim 26 , wherein the ion exchanged glass has a central tension of at least 10 MPa.

29. A glass comprising SiO 2 , Al 2 O 3 , and Na 2 O, wherein SiO 2 +B 2 O 3 ≧66 mol %, Al 2 O 3 ≧7 mol %, B 2 O 3 ≦6.27 mol %, Na 2 O≧9 mol %, B 2 O 3 +Na 2 O+K 2 O+MgO+CaO≧18 mol %, and CaO≦2 mol %, and having a breakdown margin T margin , wherein T margin (° C.)=446.6−50.2[Al 2 O 3 ]+22.6[B 2 O 3 ]−4.4[Na 2 O]−3.9[K 2 O]−1.2[MgO+CaO], where concentrations [Al 2 O 3 ], [B 2 O 3 ], [Na 2 O], [K 2 O], [MgO], and [CaO] are expressed in mol %, and wherein T margin ≧0.

30. A glass comprising SiO 2 , Al 2 O 3 , and at least one alkali metal oxide which includes Na 2 O and, optionally, at least one of K 2 O and Rb 2 O, wherein SiO 2 +B 2 O 3 ≧66 mol %, Al 2 O 3 ≧7 mol %, B 2 O 3 ≦6.27 mol %, Na 2 O≧9 mol %, B 2 O 3 +Na 2 O+K 2 O+MgO+CaO≧18 mol %, and CaO≦2 mol %, and having a breakdown margin T margin , wherein T margin =T breakdown −T 35kp , wherein T margin (° C.)=446.6−50.2[Al 2 O 3 ]+22.6[B 2 O 3 ]−4.4[Na 2 O]−3.9[K 2 O]−1.2[MgO+CaO] where concentrations [Al 2 O 3 ], [B 2 O 3 ], [Na 2 O], [K 2 O], [MgO], and [CaO] are expressed in mol %, and wherein T margin ≧0.

31. The glass of claim 30 , wherein the glass has a temperature T 35kp at which the glass has a viscosity of 35 kpoise and a zircon breakdown temperature T breakdown at which zircon breaks down to form ZrO 2 and SiO 2 , wherein T breakdown is greater than T 35kp , and wherein T margin =T breakdown −T 35kp .

32. The glass of claim 30 , wherein the glass comprises: 61 mol %≦SiO 2 ≦75 mol %; 7 mol %≦Al 2 O 3 ≦15 mol %; 0 mol %≦B 2 O 3 ≦6.27 mol %; 9 mol %≦Na 2 O≦21 mol %; 0 mol %≦K 2 O≦4 mol %; 0 mol %≦MgO≦7 mol %; and 0 mol %≦CaO≦2 mol %.

33. The glass of claim 30 , wherein the glass has less than one inclusion of solid ZrO 2 per pound of glass.

34. The glass of claim 30 , wherein the glass is ion exchanged to form a compressive layer on at least one surface of the glass, and wherein the ion exchanged glass has a compressive stress of at least 350 MPa and a compressive depth of layer of at least 20 microns.

35. The glass of claim 34 , wherein the ion exchanged glass has a central tension of at least 10 MPa.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 16, 2010
From: DEJNEKA, MATTHEW JOHN; ELLISON, ADAM JAMES; HANSON, BENJAMIN ZAIN
To: CORNING INCORPORATED
Reel/Frame 024998/0432 →
Continuity (2)
Provisional Application 61235762 · Aug 21, 2009
Related Publication 20110045961A1 · Feb 24, 2011