US3307987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of making a gypsum wallboard having a decreased starch content in the gypsum core
Assignee: National Gypsum Co
•
Filing: 1959-08-12
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Granted: 1967-03-07
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Expires: 1979-08-12
Abstract
No abstract record available.
Inventors
- 👤 Bieri David
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:47
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/14; E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/043; C04B2103/00; C04B2103/60; C04B2103/65; C04B2111/00; C04B2111/00474; C04B2111/00612; C04B2111/0062
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
77 words
THE METHOD OF MAKING PAPER COVERED GYPSUM WALLBOARD COMPRISING THE STEPS OF FORMING INTO BOARD FORM AN AQUEOUS CALCINED GYPSUM SLURRY BETWEEN TWO PAPER LINERS, SAID AQUEOUS CALCINED GYPSUM SLURRY CONTAINING ABOUT 2 POUNDS OF STARCH PER THOUSAND SQUARE FEET PER 3/8 INCH OF THICKNESS, EACH OF SAID LINERS BEING OF ABOUT .020 INCH THICKNESS, WITH SAID PAPER LINER INNER SURFACES BEING DISPOSED INWARDLY FOR BONDIN TO SAID GYPSUM, SAID PAPER LINERS HAVING, IMMEDIATELY PRIOR TO SAID
Claim 2
Independent Claim
77 words
THE METHOD OF MAKING PAPER COVERED GYPSUM WALLBOARD COMPRISING THE STEPS OF FORMING INTO BOARD FORM AN AQUEOUS CALCINED GYPSUM SLURRY BETWEEN TWO PAPER LINERS, SAID AQUEOUS CALCINED GYPSUM SLURRY CONTAINING ABOUT 2 POUNDS OF STARCH PER THOUSAND SQUARE FEET PER 3/8 INCH OF THICKNESS, EACH OF SAID LINERS BEING OF ABOUT .020 INCH THICKNESS, WITH SAID PAPER LINER INNER SURFACES BEING DISPOSED INWARDLY FOR BONDIN TO SAID GYPSUM, SAID PAPER LINERS HAVING, IMMEDIATELY PRIOR TO SAID
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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) | 1970-03-06 | 1970-09-05 | 1971-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-03-06 | 1974-09-05 | 1975-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-03-06 | 1978-09-05 | 1979-03-07 | $7700.00 | Window Closed / Lapsed |