US3853689A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sag resistant gypsum board and method
Assignee: Johns Manville Corp
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Filing: 1972-06-01
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Granted: 1974-12-10
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Expires: 1992-06-01
Abstract
Abstract The sag resistance of gypsum board is improved by incorporating a small amount of polyvinyl alcohol in the gypsum core of the board.
Inventors
- 👤 N Morrone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:52
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/30; B32B27/306; C; C04; C04B; C04B24/00; C04B24/24; C04B24/26; C04B24/2623; B32B27/06; B32B27/10; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/3188; Y10T428/31895; Y10T428/31971; Y10T428/31993; Y10T428/31996
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
62 words
A GYPSUM BOARD COMPRISING A CORE OF SET GYPSUM HAVING INCORPORATED THEREIN POLYVINYL ALCOHOL IN AN AMOUNT OF FROMAPPORXIMATELY 0.15 TO ABOUT 0.40 PERCENB BY WEIGHT OF THE GYPSUM IN THE CORE WHEREBY TO IMPROVE THE SAG RESISTANCE OF THE BOARD, AND A PAIR OF PAPER COVER SHEETS WITH ONE COVER SHEET ADHERED TO EACH FACE OF THE CORE OF SET GYPSUM.
Claim 2
Dependent Claim
62 words
A GYPSUM BOARD COMPRISING A CORE OF SET GYPSUM HAVING INCORPORATED THEREIN POLYVINYL ALCOHOL IN AN AMOUNT OF FROMAPPORXIMATELY 0.15 TO ABOUT 0.40 PERCENB BY WEIGHT OF THE GYPSUM IN THE CORE WHEREBY TO IMPROVE THE SAG RESISTANCE OF THE BOARD, AND A PAIR OF PAPER COVER SHEETS WITH ONE COVER SHEET ADHERED TO EACH FACE OF THE CORE OF SET GYPSUM.
Claim 3
Dependent Claim
17 words
The gypsum board of claim 1 in which the gypsum core contains about 0.33 percent polyvinyl alcohol.
Claim 4
Dependent Claim
35 words
The gypsum board of claim 1 in which the molecular weight of the polyvinyl alcohol is from 5,000 - 15,000, and the polyvinyl alcohol has a residual polyvinyl acetate content of 15-25 percent by weight.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |