US4590171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low temperature lead and cadmium-free frits
Assignee: Corning Glass Works
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Filing: 1985-05-29
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Granted: 1986-05-20
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Expires: 2005-05-29
Abstract
Abstract This invention relates to the production of frits especially suitable for use in contact with foods. The frits are essentially free from cadmium and lead and consist essentially, in weight percent on the oxide basis, of: Li 2 O: 3-4 Na 2 O: 0.75-3 BaO: 3.5-9.5 B 2 O 3 : 14-17.5 Al 2 0 3 : 6.75-8.75 SiO 2 : 48-55 ZrO 2 : 6.75-10.5 F: 3-4.
Inventors
- 👤 Jaroslava M. Nigrin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:38
CPC Classifications
C; C03; C03C; C03C8/00; C03C8/02; C03C8/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
94 words
A frit essentially free from cadmium and lead demonstrating good glass stability, a coefficient of thermal expansion (20°-300° C.) between about 58-62×10 -7 /°C., a softening point between about 600°-625° C., and excellent resistance to attack by acids found in foods and to attack by alkaline detergents, said frit consisting essentially, expressed in terms of weight percent on the oxide basis, of Li 2 O: 3-4 Na 2 O: 0.75-3 BaO: 3.5-9.5 B 2 O 3 : 14-17.5 Al 2 O 3 : 6.75-8.75 SiO 2 : 48-55 ZrO 2 : 6.75-10.5 F: 3-4.
Claim 2
Dependent Claim
94 words
A frit essentially free from cadmium and lead demonstrating good glass stability, a coefficient of thermal expansion (20°-300° C.) between about 58-62×10 -7 /°C., a softening point between about 600°-625° C., and excellent resistance to attack by acids found in foods and to attack by alkaline detergents, said frit consisting essentially, expressed in terms of weight percent on the oxide basis, of Li 2 O: 3-4 Na 2 O: 0.75-3 BaO: 3.5-9.5 B 2 O 3 : 14-17.5 Al 2 O 3 : 6.75-8.75 SiO 2 : 48-55 ZrO 2 : 6.75-10.5 F: 3-4.
Claim 3
Dependent Claim
58 words
A frit according to claim 1 also containing up to 7.5% total of at least one metal oxide in the indicated proportion selected from the group of 0-3% Bi 2 O 3 , 0-1.5% CaO, 0-2% K 2 O, 0-5% Sb 2 O 3 , 0-2% SnO 2 , 0-2% SrO, 0-3% TiO 2 , and 0-2.5% ZnO.
References Cited (Backward Citations)
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US4311504A
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US4316963A
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US4417913A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |