US2803575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gypsum board
Assignee: Kaiser Gypsum Co Inc
•
Filing: 1953-08-17
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Granted: 1957-08-20
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Expires: 1973-08-17
Abstract
No abstract record available.
Inventors
- 👤 Wallace C Riddell
- 👤 George B Kirk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:49
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/044; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249967; Y10T428/249968; Y10T428/249971; Y10T428/249973
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
102 words
A METHOD OF PREPARING A LIGHTWEIGHT FLEXIBLE WALLBOARD WEIGHT FROM 1600 TO 190 POUNDS PER THOUSAND SQUARE FEET AT ONE-HALF THICKNESS, WHICH COMPRISES PREPARING AN ADMIXTURE OF CALCINED GYPSUM AND FROM 0.5% TO 10% BY WEIGHT OF EXPANDED VESICULATED PERLITE HAVING A BULK DENSITY OF FROM 5 TO 15 POUNDS PER CUBIC FOOT AND OF PARTICLE SIZE SUBSTANTIALLY ENTIRELY PASSING A NO. 8 SCREEN AND RETAINED ON A NO. 100 SCREEN, ADMIXING WITH WATER TO FORM A PLASTIC SLURRY, DEPOSITING AND SLURRY BETWEEN FIBROUS LINERS AND FORMING INTO A BOARD AND DRYING AND HARDENING AT A TEMPERATURE OF NOT OVER ABOUT 400*F.
References Cited (Backward Citations)
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Cited
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Cited
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Cited
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Cited
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Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-08-19 | 1961-02-18 | 1961-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-19 | 1965-02-18 | 1965-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-19 | 1969-02-18 | 1969-08-20 | $7700.00 | Window Closed / Lapsed |