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US3967969A
Expired / Lapsed
US
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High zirconia containing glass ceramic cement
Assignee: National Research Development Corp UK
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Filing: 1974-07-09
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Granted: 1976-07-06
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Expires: 1994-07-09
Abstract
Abstract A glass ceramic cement comprising by weight 20% to 45% ZrO 2 , 20% to 60% Al 2 O 3 , 0% to 27% SiO 2 , 0% to 30% CaO, 0% to 10% Na 2 O, the cement including at least one material selected from the group B 2 O 3 and PbO, in the amounts up to 35% and 25% respectively, sufficient to assist in taking ZrO 2 into solution during the melting of said glass ceramic cement, B 2 O 3 in the absence of PbO being in an amount more than 5%, PbO in the absence of B 2 O 3 being in an amount more than 2%.
Inventors
- 👤 Terence Stanley Busby
- 👤 Geoffrey Charles Cox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:14
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/48; C03; C03C; C03C10/00; C03C10/0036; C04B35/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
112 words
A glass ceramic cement comprising by weight 20% to 45% ZrO 2 , 20% to 60% Al 2 O 3 , 0% to 27% SiO 2 , 0% to 30% CaO, 0% to 10% Na 2 O, the cement including at least one material selected from the group B 2 O 3 and PbO, in the amounts up to 35% and 25% respectively, sufficient to assist in taking ZrO 2 into solution during the melting of said glass ceramic cement, B 2 O 3 in the absence of PbO being in an amount more than 5%, PbO in the absence of B 2 O 3 being in an amount more than 2%.
Claim 2
Dependent Claim
112 words
A glass ceramic cement comprising by weight 20% to 45% ZrO 2 , 20% to 60% Al 2 O 3 , 0% to 27% SiO 2 , 0% to 30% CaO, 0% to 10% Na 2 O, the cement including at least one material selected from the group B 2 O 3 and PbO, in the amounts up to 35% and 25% respectively, sufficient to assist in taking ZrO 2 into solution during the melting of said glass ceramic cement, B 2 O 3 in the absence of PbO being in an amount more than 5%, PbO in the absence of B 2 O 3 being in an amount more than 2%.
Claim 3
Dependent Claim
61 words
A glass ceramic cement as in claim 1, comprising by weight 20% to 45% ZrO 2 , 25% to 55% Al 2 O 3 , 2% to 27% SiO 2 , 0% to 30% CaO, 0% to 10% Na 2 O the cement including B 2 O 3 and/or PbO in the amounts 0% to 35% and 0% to 25% respectively.
Claim 4
Dependent Claim
56 words
A glass ceramic cement as in claim 1, comprising by weight 20% to 29% ZrO 2 , 37% to 54% Al 2 O 3 , 8% to 27% SiO 2 , 0% to 16% CaO, 0% to 2% Na 2 O, and B 2 O 3 and/or PbO in amounts up to 19% and 8% respectively.
References Cited (Backward Citations)
US3826659A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-06 | 1980-01-05 | 1980-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-06 | 1984-01-05 | 1984-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-06 | 1988-01-05 | 1988-07-06 | $7700.00 | Window Closed / Lapsed |