High strength sealing glass

• US 6,245,699 B1
• Filed: 04/30/1999
• Issued: 06/12/2001
• Est. Priority Date: 04/30/1999
• Status: Expired due to Fees

• Current Assignee: Techneglas, Inc.
• Original Assignee: Techneglas, Inc.
• Inventors: Hudecek, Carl J., Bobinski, Jon G., Peer, Joseph V.
• Primary Examiner(s): Sample, David R
• Application Number:
  US09/303,297
• Time in Patent Office: 774 Days
• Field of Search: 501/15, 501/18, 501/22, 501/26, 501/32, 501/76, 501/79, 501/49, 501/52, 65/43, 445/24, 445/25
• US Class Current: 501/18
• CPC Class Codes: C03C 8/14 Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
• CPC Class Codes: C03C 8/20 containing titanium compounds; containing zirconium compounds
• CPC Class Codes: C03C 8/245 containing more than 50% lead oxide, by weight

Abstract

A sealing glass composition in powdered form comprising a crystallizable base glass in the vitreous state and vanadium zirconium silicate in an amount from about 0.1 to 1 weight percent of the base glass. The sealing glass also may contain aluminum oxide having a particle size of about 90 to 99 percent minus 325 mesh in an amount from about 0.1 to 1.0 weight percent of the base glass and bismuth nitrate in an amount from about 0.02 to 0.08 weight percent of the base glass. The glass composition can be used to seal cathode ray tube face plates and funnels with excellent results when heated to a hold range of about 4300 C to 4500 C. The crystallized sealing glass exhibits improved adhesion to seal edges of the face plates and funnels, increased strength, and improved resistance to organic contamination.

Claims

1. A sealing glass composition, comprising:

a crystallizable base glass; and

vanadium zirconium silicate in an amount from about 0.1 to 1 weight percent of the base glass.

2. The sealing glass composition according to claim 1, wherein the amount of vanadium zirconium silicate is about 0.3 to 0.7 weight percent of the base glass.

3. The sealing glass composition according to claim 1, wherein the vanadium zirconium silicate generally has a particle size of minus 325 mesh.

4. The sealing glass composition according to claim 1, further comprising:

aluminum oxide having a particle size of about 90 to 99 percent minus 325 mesh in an amount from about 0.1 to 1.0 weight percent of the base glass.

5. The sealing glass composition according to claim 4, wherein the amount of aluminum oxide is about 0.2 to 0.4 weight percent of the base glass.

6. The sealing glass composition according to claim 1, further comprising:

aluminum oxide particles in an amount from about 0.1 to 1.0 weight percent of the base glass, the aluminum oxide particles being of such size that the surface of the aluminum oxide particles is partially but not totally melted when the composition is heated to about 430°

C. to 450°

C. for about 17 to 60 minutes.

7. The sealing glass composition according to claim 1, further comprising:

bismuth nitrate in an amount from about 0.02 to 0.08 weight percent of the base glass.

8. The sealing glass composition according to claim 7, wherein the amount of bismuth nitrate is about 0.03 to 0.06 weight percent of the base glass.

9. The sealing glass composition according to claim 1, further comprising:

aluminum oxide having a particle size of about 90 to 99 percent minus 325 mesh in an amount from about 0.1 to 1.0 weight percent of the base glass; and

bismuth nitrate in an amount from about 0.02 to 0.08 weight percent of the base glass.

10. The sealing glass composition according to claim 9, wherein the amount of vanadium zirconium silicate is about 0.3 to 0.7 weight percent of the base glass, the amount of aluminum oxide is about 0.2 to 0.3 weight percent of the base glass, and the amount of bismuth nitrate is about 0.03 to 0.06 weight percent of the base glass.

11. The sealing glass composition according to claim 9, further comprising:

a nucleating agent.

12. The sealing glass composition according to claim 11, wherein the nucleating agent comprises zinc zirconium silicate.

13. The sealing glass composition according to claim 12, wherein the amount of zinc zirconium silicate is sufficient to form a devitrified seal suitable for sealing television picture tube components as evidenced by a DTA peak of 17 to 30 minutes when the composition is heated to a hold range of about 430°

C. to 450°

C.

14. The sealing glass composition according to claim 1, wherein the nucleating agent comprises zinc zirconium silicate having a particle size of about 2 to 8 microns and zirconium silicate having a particle size of about 99.98 percent minus 325 mesh.

15. The sealing glass composition according to claim 14, wherein the amount of zinc zirconium silicate is about 0.02 to 0.7 weight percent of the base glass and the amount of zirconium silicate nucleating agent is about 0.1 to 0.4 weight percent of the base glass.

16. The sealing glass composition according to claim 11, further comprising a filler in an amount from about 0.1 to 1.0 weight percent of the base glass.

17. The sealing glass composition according to claim 16, wherein the filler comprises zirconium silicate filler having a particle size of about 90 percent minus 325 mesh.

18. The sealing glass composition according to claim 17, wherein the amount of zirconium silicate filler is about 0.1 to 0.6 weight percent of the base glass.

19. The sealing glass composition according to claim 9, further comprising:

manganese sesquioxide.

20. The sealing glass composition according to claim 19, wherein the amount of manganese sesquioxide is about 0.2 to 1.4 weight percent of the base glass.

21. The sealing glass composition according to claim 1, wherein the base glass comprises the following ingredients in approximate percent by weight:

22. The sealing glass composition according to claim 21, wherein the base glass comprises the following ingredients in approximate percent by weight:

23. The sealing glass composition according to claim 22, wherein the base glass comprises the following ingredients in approximate percent by weight:

24. The sealing glass composition according to claim 9, wherein the composition comprises the following ingredients in approximate percent by weight:

25. The sealing glass composition according to claim 24, wherein the composition comprises the following ingredients in approximate percent by weight:

26. The sealing glass composition according to claim 9, wherein the composition comprises the following ingredients in approximate percent by weight:

27. The sealing glass composition according to claim 9, wherein the base glass particles are milled using large round milling media.

28. A sealing glass composition for sealing a glass face plate and funnel, comprising:

a crystallizable base glass;

vanadium zirconium silicate in an amount from about 0.1 to 1 weight percent of the base glass for improving adhesion of the liquefied sealing glass composition to seal edges of the face plate and funnel;

aluminum oxide having a particle size of about 90 to 99 percent minus 325 mesh in an amount from about 0.1 to 1.0 weight percent of the base glass for increasing the strength of the crystallized sealing glass matrix; and

bismuth nitrate in an amount from about 0.02 to 0.08 weight percent of the base glass for improving resistance to organic contamination during sealing.

29. The sealing glass composition according to claim 28, wherein the vanadium zirconium silicate generally has a particle size of minus 325 mesh.

30. The sealing glass composition according to claim 28, wherein the base glass is milled using large round milling media to produce smooth particles.

31. The sealing glass composition according to claim 28, further comprising:

zinc zirconium silicate in an amount from about 0.02 to 0.7 weight percent for nucleating controlled crystallization of the sealing glass composition; and

zirconium silicate in an amount from about 0.1 to 0.4 weight percent for enhancing nucleation and reducing crystallization time.

32. The sealing glass composition according to claim 31, further comprising:

a filler in an amount from about 0.1 to 1.0 weight percent of the base glass.

33. The sealing glass composition according to claim 32, wherein the filler comprises zirconium silicate having a particle size of about 90 percent minus 325 mesh.

34. A method of making a sealing glass composition that forms satisfactory devitrified seals when heated to a hold range of about 430°

C. to 450°

C., said method comprising the steps of;

selecting a crystallizable base glass in the vitreous state;

adding bismuth nitrate to the base glass in an amount from about 0.02 to 0.08 weight percent of the base glass;

blending vanadium zirconium silicate particles in an amount from about 0.1 to 1 weight percent of the base glass into the glass composition; and

blending aluminum oxide having a particle size of about 90 to 99 percent minus 325 mesh in an amount from about 0.1 to 1.0 weight percent of the base glass into the glass composition.

35. The method according to claim 34, further comprising the step of:

providing vanadium zirconium silicate generally having a particle size of minus 325 mesh.

36. The method according to claim 34, wherein the step of adding bismuth nitrate further comprises the step of uniformly distributing bismuth nitrate in the base glass.

37. The method according to claim 34, further comprising the step of:

milling the base glass using large round milling media to produce smooth particles.

38. The method according to claim 37, wherein the base glass particles have a mean particle size of 15-23 microns.

39. The method according to claim 34, further comprising the steps of:

adding an effective nucleating amount of zinc zirconium silicate.

40. The method according to claim 34, further comprising the step of:

adding very fine granular zirconium silicate.

41. The method according to claim 34, further comprising the step of:

adding a filler.

42. A method of sealing glass face plates and funnels, comprising the steps of:

selecting a crystallizable base glass in the vitreous state;

uniformly distributing bismuth nitrate in an amount from about 0.02 to 0.08 weight percent of the base glass into the base glass;

blending vanadium zirconium silicate in an amount from about 0.1 to 1 weight percent of the base glass into the glass composition;

blending aluminum oxide having a particle size of about 90 to 99 percent minus 325 mesh in an amount from about 0.1 to 1.0 weight percent of the base glass into the glass composition;

applying a sealing amount of the sealing glass composition between the sealing edges of the face plate and funnel; and

subjecting the applied sealing glass composition to a sealing temperature within the sealing temperature range of between about 430°

C. and 450°

C. for a time sufficient to fuse the sealing glass composition and form a seal to and between the sealing edges of the face plate and funnel.

43. The method of claim 42 further comprising the step of:

providing vanadium zirconium silicate generally having a particle size of minus 325 mesh.

44. The method according to claim 42, further comprising the step of:

milling the base glass using large round milling media to produce smooth particles.

45. The method according to claim 42, further comprising the step of:

adding an effective amount of at least one nucleating agent such that the crystallizing glass composition has a peak at about 17 to 30 minutes when the composition is heated to the hold range of about 430°

C. to 450°

C. as evidenced by a DTA curve.