Fining agents for silicate glasses

• US 10,626,042 B2
• Filed: 06/04/2015
• Issued: 04/21/2020
• Est. Priority Date: 02/26/2008
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Dejneka, Matthew John, Gomez, Sinue
• Primary Examiner(s): Lazorcik, Jason L
• Application Number:
  US14/730,354
• Publication Number:
  US 20150266768A1
• Time in Patent Office: 1,783 Days
• CPC Class Codes: C03B 17/064 by the overflow downdraw fusion process; Isopipes therefor
• CPC Class Codes: C03B 5/225 Refining C03B5/18 takes precedence ; Refining agents C03C1/004
• CPC Class Codes: C03C 1/004 Refining agents refining C03B5/225
• CPC Class Codes: C03C 14/008 the non-glass component being in molecular form
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/083 containing aluminium oxide or an iron compound
• CPC Class Codes: C03C 3/085 containing an oxide of a divalent metal
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/095 containing rare earths
• CPC Class Codes: Y02A 40/28 specially adapted for farming
• CPC Class Codes: Y10T 428/315 Surface modified glass [e.g., tempered, strengthened, etc.]

Abstract

A fining agent for reducing the concentration of seeds or bubbles in a silicate glass. The fining agent includes at least one inorganic compound, such as a hydrate or a hydroxide that acts as a source of water. In one embodiment, the fining agent further includes at least one multivalent metal oxide and, optionally, an oxidizer. A fusion formable and ion exchangeable silicate glass having a seed concentration of less than about 1 seed/cm³ is also provided. Methods of reducing the seed concentration of a silicate glass, and a method of making a silicate glass having a seed concentration of less than about 1 seed/cm³ are also described.

Claims

1. A method of making a silicate glass having a seed concentration of less than about 1 seed/cm³, wherein the method comprises:

melting at a first temperature a glass batch comprising 60-70 mol % SiO₂;

6-14 mol % Al₂O₃;

0-3 mol % B₂O₃;

0-1 mol % Li₂O;

8-18 mol % Na₂O;

0-5 mol % K₂O;

0-2.5 mol % CaO;

above 0 to 3 mol % ZrO₂; and

a fining agent, wherein 12 mol %≤

Li₂O +Na₂O+K₂O≤

20 mol %, and wherein the glass batch comprises less than 50 ppm As₂O₃; and

heating at a second temperature greater than the first temperature for a time sufficient to produce the silicate glass having a seed concentration of less than about 1 seed/cm³,

wherein the fining agent is selected from the group consisting of SnO₂, CeO₂, and combinations thereof, and the fining agent comprises from 0-1 mol % SnO₂ and 0-1 mol % CeO₂ of the glass batch.

2. The method of claim 1 wherein the first temperature is about 1425°

C. to about 1550°

C. and the second temperature is about 1525°

C. to about 1675°

C.

3. The method of claim 1 wherein the difference between the second temperature and the first temperature is about 50°

C. to about 250°

C.

4. The method of claim 3 wherein the difference between the second temperature and the first temperature is about 75°

C. to about 100°

C.

5. The method of claim 1 wherein the glass batch comprises at least one inorganic compound that acts as of a source of H₂O at a temperature where a melt is formed.

6. The method of claim 1 wherein the glass batch comprises an oxidizer fining agent.

7. The method of claim 1 wherein the glass batch comprises fining agent selected from the group consisting of aluminum hydroxide, sodium hydroxide, or combinations thereof.

8. The method of claim 1 further comprising ion exchanging the silicate glass to achieve a surface compressive stress of at least about 200 MPa and a surface compressive layer having a depth of at least about 30 μ

m.

9. The method of claim 1 further comprising forming a glass sheet from the silicate glass via down-draw method.

10. The method of claim 1, wherein the glass batch further comprises at least one clay or zeolite.

11. The method of claim 1, wherein the glass batch further comprises aluminum silicate hydroxides, talc, montmorillonitesmectite, and combinations thereof.

12. A method of making a silicate glass having a seed concentration of less than about 1 seed/cm³, wherein the method comprises:

melting at a first temperature a glass batch comprising 60-70 mol % SiO₂;

0-3 mol % B₂O₃;

0-1 mol % Li₂O;

8-18 mol % Na₂O;

0-5 mol % K₂O;

0-2.5 mol % CaO;

above 0 to 3% mol ZrO₂; and

a fining agent, wherein 12 mol %<

Li₂O+Na₂O+K₂O≤

20 mol %, and wherein the glass batch is substantially free of As₂O₃; and

heating at a second temperature greater than the first temperature for a time sufficient to produce the silicate glass having a seed concentration of less than about 1 seed/cm³,

wherein the fining agent is selected from the group consisting of SnO₂, CeO₂, and combinations thereof, and the fining agent comprises 0-1 mol % SnO₂ and 0-1 mol % CeO₂ of the glass batch.

13. The method of claim 12 wherein the first temperature is about 1425°

C. to about 1550°

C. and the second temperature is about 1525°

C. to about 1675°

C.

14. The method of claim 12 wherein the difference between the second temperature and the first temperature is about 50°

C. to about 250°

C.

15. The method of claim 14 wherein the difference between the second temperature and the first temperature is about 75°

C. to about 100°

C.

16. The method of claim 12 wherein the glass batch comprises at least one inorganic compound that acts as of a source of H₂O at a temperature where a melt is formed.

17. The method of claim 12 wherein the glass batch comprises an oxidizer fining agent.

18. The method of claim 12 wherein the glass batch comprises fining agent selected from the group consisting of aluminum hydroxide, sodium hydroxide, or combinations thereof.

19. The method of claim 12 further comprising ion exchanging the silicate glass to achieve a surface compressive stress of at least about 200 MPa and a surface compressive layer having a depth of at least about 30 μ

m.

20. The method of claim 12 further comprising forming a glass sheet from the silicate glass via down-draw method.

21. A method of making a silicate glass having a seed concentration of less than about 1 seed/cm³, wherein the method comprises:

melting at a first temperature a glass batch comprising 60-70 mol % SiO₂;

6-14 mol % Al₂O₃;

0-15 mol % B₂O₃;

0-1 mol % Li₂O;

0-20 mol % Na₂O;

0-10 mol % K₂O;

0-10 mol % CaO;

0-5 mol % ZrO₂;

wherein 12 mol %≤

Li₂O+Na₂O+K₂O≤

20 mol %, wherein the glass batch comprises less than 50 ppm As₂O₃, wherein the glass batch comprises a fining agent comprising a multivalent metal oxide, an oxidizer, and at least one inorganic compound that acts as of a source of water at a temperature where a melt is formed; and

heating at a second temperature greater than the first temperature for a time sufficient to produce the silicate glass having a seed concentration of less than about 1 seed/cm³.

22. The method of claim 21 wherein the first temperature is about 1425°

C. to about 1550°

C. and the second temperature is about 1525°

C. to about 1675°

C.

23. The method of claim 21 wherein the difference between the second temperature and the first temperature is about 50°

C. to about 250°

C.

24. The method of claim 23 wherein the difference between the second temperature and the first temperature is about 75°

C. to about 100°

C.

25. The method of claim 21 wherein the glass batch comprises at least one inorganic compound that acts as of a source of H₂O at a temperature where a melt is formed.

26. The method of claim 21 wherein the glass batch comprises an oxidizer fining agent.

27. The method of claim 21 wherein the glass batch comprises fining agent selected from the group consisting of aluminum hydroxide, sodium hydroxide, or combinations thereof.

28. The method of claim 21 further comprising ion exchanging the silicate glass to achieve a surface compressive stress of at least about 200 MPa and a surface compressive layer having a depth of at least about 30 μ

m.

29. The method of claim 21 further comprising forming a glass sheet from the silicate glass via down-draw method.

30. The method of claim 21 wherein the multivalent oxide fining agent is selected from the group consisting of SnO₂, CeO₂, and combinations thereof.