Patent US4957674A successfully refreshed from Google Patents.
US4957674A
Expired / Lapsed
US
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Method for producing calcium phosphate-based material
Assignee: Pentax Corp
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Filing: 1988-05-11
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Granted: 1990-09-18
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Expires: 2008-05-11
Abstract
Abstract A method for producing a calcium phosphate-based material comprising: (a) molding a calcium phosphate powder; (b) preliminarily calcining the resulting molding in a vacuum or under a reduced pressure until the relative density is 95% or more; and (c) firing the molding in air, an inert gas, or nitrogen gas.
Inventors
- 👤 Takeshi Ichitsuka
- 👤 Yasuhiko Hirayama
- 👤 Tetsuro Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:27
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/02; A61L27/12; A61K; A61K6/00; A61K6/80; A61K6/831; A61K6/838; C; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/32; C01B25/327; C01B25/38; C01B25/42; C01B25/44; C01B25/455; A61F; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
75 words
A method for producing a calcium phosphate-based material comprising: (a) molding a calcium phosphate powder; (b) preliminarily calcining the resulting molding in a vacuum or under a reduced pressure until the relative density is 95% or more; and (c) firing said molding in air, an inert gas, or nitrogen gas, wherein said preliminary calcining is carried out under a pressure of less than 1 Torr and at a temperature of from 950° to 1,100° C.
Claim 2
Independent Claim
75 words
A method for producing a calcium phosphate-based material comprising: (a) molding a calcium phosphate powder; (b) preliminarily calcining the resulting molding in a vacuum or under a reduced pressure until the relative density is 95% or more; and (c) firing said molding in air, an inert gas, or nitrogen gas, wherein said preliminary calcining is carried out under a pressure of less than 1 Torr and at a temperature of from 950° to 1,100° C.
Claim 3
Dependent Claim
29 words
A method for producing a calcium phosphate-based material as claimed in claim 1, wherein said final firing is carried out at a temperature of from 1,000° to 1,400° C.
Claim 4
Dependent Claim
76 words
A method for producing a calcium phosphate-based material as claimed in claim 1, wherein said calcium phosphate powder is at least one member selected from the group consisting of Ca 10 (PO 4 ) 6 (OH) 2 , Ca 3 (PO 4 ) 2 , Ca 2 P 2 O 7 , Ca(PO 3 ) 2 , Ca 10 (PO 4 ) 6 F 2 , and Ca 10 (PO 4 ) 6 Cl 2 .
Claim 5
Dependent Claim
28 words
A method for producing a calcium phosphate-based material as claimed in claim 3, wherein said calcium phosphate powder is Ca 10 (PO 4 ) 6 (OH) 2 .
Claim 6
Dependent Claim
27 words
A method for producing a calcium phosphate-based material as claimed in claim 1, wherein said preliminary calcining is carried out for about from 0.5 to 5 hours.
Claim 7
Dependent Claim
23 words
A method for producing a calcium phosphate-based material as claimed in claim 1, wherein said inert gas is argon gas or helium gas.
Claim 8
Dependent Claim
26 words
A method for producing a calcium phosphate-based material as claimed in claim 1, wherein said firing is carried out for about from 0.5 to 5 hours.
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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) | 1993-09-17 | 1994-03-19 | 1994-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-17 | 1998-03-19 | 1998-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-17 | 2002-03-19 | 2002-09-18 | $7700.00 | Window Closed / Lapsed |