US3856540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cement additive
Assignee: Denka Co Ltd
•
Filing: 1973-01-26
•
Granted: 1974-12-24
•
Expires: 1993-01-26
Abstract
Abstract A cement additive consisting of calcium sulfate and calcium fluoroaluminate having the chemical formula 3CaO.3Al2O3.CaF2.
Inventors
- 👤 T Mizunuma
- 👤 T Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:18
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/02; C04B22/00; C04B22/0093
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
26 words
A CEMENT ADDITIVE COMPRISING CALCIUM SULFATE FROM 20 TO 90% BY WEIGHT AND CALCIUM FLUOROALUMINATE HAVING THE CHEMICAL FORMULA 3CAO.3AL2O3.CAF2 FROM 80 TO 10% BY WEIGHT.
Claim 2
Dependent Claim
26 words
A CEMENT ADDITIVE COMPRISING CALCIUM SULFATE FROM 20 TO 90% BY WEIGHT AND CALCIUM FLUOROALUMINATE HAVING THE CHEMICAL FORMULA 3CAO.3AL2O3.CAF2 FROM 80 TO 10% BY WEIGHT.
Claim 3
Dependent Claim
47 words
A cement composition comprising cement from 99 to 70% by weight and a cement additive from 1 to 30% by weight, said cement additive comprising calcium sulfate from 20 to 90% by weight and calcium fluoroaluminate having the chemical formula 3CaO.3Al2O3.CaF2 from 80 to 10% by weight.
Claim 4
Dependent Claim
47 words
A cement composition comprising cement from 99 to 70% by weight and a cement additive from 1 to 30% by weight, said cement additive comprising calcium sulfate from 20 to 90% by weight and calcium fluoroaluminate having the chemical formula 3CaO.3Al2O3.CaF2 from 80 to 10% by weight.
References Cited (Backward Citations)
US1904640A
Cited
US3628973A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |