Patent US4772573A successfully refreshed from Google Patents.
US4772573A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-strength sintered article of calcium phosphate compound, raw material for production of said sintered article, and method for production of said sintered article
Assignee: National Institute of Advanced Industrial Science and Technology
•
Filing: 1987-01-02
•
Granted: 1988-09-20
•
Expires: 2007-01-02
Abstract
Abstract Sintered article suitable for artificial bones, for example, containing a calcium phosphate compound as a main component and additionally containing spinel or magnesium oxide formed by sintering magnesium oxalate dihydrate. This sintered article is produced by adding alumina and silica or magnesium oxalate dihydrate to a calcium phosphate compound and firing the resultant mixture.
Inventors
- 👤 Motohiro Toriyama
- 👤 Sukezo Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:10
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/02; A61L27/12; A61F; A61F2/00; A61F2/02; A61F2/28; A61K; A61K6/00; A61K6/50; A61K6/58; A61K6/80; A61K6/802; A61K6/807; A61K6/831; A61K6/838; C; C04; C04B; C04B35/00; C04B35/01; C04B35/447; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
64 words
A sintered article consisting essentially of tricalcium phosphate and 0.5 to 5% weight of needle crystals of mullite prepared by firing at a temperature of 1,100° to 1,500° C. a composition consisting essentially of tricalcium phosphate, silica in amount of 1 to 10% by weight, and alumina in an amount of 2 to 10% by weight, both based on the amount of tricalcium phosphate.
Claim 2
Dependent Claim
64 words
A sintered article consisting essentially of tricalcium phosphate and 0.5 to 5% weight of needle crystals of mullite prepared by firing at a temperature of 1,100° to 1,500° C. a composition consisting essentially of tricalcium phosphate, silica in amount of 1 to 10% by weight, and alumina in an amount of 2 to 10% by weight, both based on the amount of tricalcium phosphate.
Claim 3
Dependent Claim
18 words
The sintered article of claim 1, wherein the silica and alumina are in the form of a powder.
Claim 4
Dependent Claim
50 words
A raw material for the preparation of the sintered article of claim 1, consisting essentially of a mixture of tricalcium phosphate, silica in an amount of 1 to 10% by weight and alumina in an amount of 2 to 10% by weight, both based on the amount of tricalcium phosphate.
Claim 5
Dependent Claim
18 words
The raw material of claim 3, wherein the silica and alumina are in the form of a powder.
Claim 6
Dependent Claim
12 words
The raw material of claim 3 in the form of a slip.
Claim 7
Dependent Claim
57 words
A method for the preparation of the sintered article of claim 1, comprising firing at a temperature of 1,100° to 1,500° C. a composition consisting essentially of tricalcium phosphate, silica in an amount of 1 to 10% by weight, and alumina in an amount of 2 to 10% by weight, both based on the amount tricalcium phosphate.
Claim 8
Dependent Claim
17 words
The method of claim 6, wherein the silica and alumina are in the form of a powder.
References Cited (Backward Citations)
US4308064A
Cited
US4376168A
Cited
US4503157A
Cited
US4613577A
Cited
US4560666A
Cited
US4643982A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-20 | 1992-03-21 | 1992-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-20 | 1996-03-21 | 1996-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-20 | 2000-03-21 | 2000-09-20 | $7700.00 | Window Closed / Lapsed |