US2640756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of tetrasilicates
Assignee: PQ Corp
•
Filing: 1948-02-09
•
Granted: 1953-06-02
•
Expires: 1968-02-09
Abstract
No abstract record available.
Inventors
- 👤 John H Wills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:21
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/20; C01B33/36; C01B33/38; C01B33/113; C01B33/12
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
8 words
AS NEW PRODUCTS BIREFRINGENT TETRASILICATES HAVING THE FORMULA
References Cited (Backward Citations)
USRE23043E
Cited
US1959748A
Cited
US2179806A
Cited
US2278590A
Cited
US2384563A
Cited
US2364015A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-01 | 1956-12-01 | 1957-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-01 | 1960-12-01 | 1961-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-01 | 1964-12-01 | 1965-06-02 | $7700.00 | Window Closed / Lapsed |