US4564544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire-resistant gypsum board
Assignee: National Gypsum Properties LLC
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Filing: 1983-12-01
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Granted: 1986-01-14
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Expires: 2003-12-01
Abstract
Abstract A fire-retardant gypsum wallboard having, in the gypsum core, about 2% by weight of a feldspar-free muscovite, in combination with other minor additives including 1/2 inch long glass fibers.
Inventors
- 👤 Edward A. Burkard
- 👤 James J. Segada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:20
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/043; C; C04; C04B; C04B14/00; C04B14/02; C04B14/04; C04B14/20; C04B28/00; C04B28/14; C04B2111/00; C04B2111/00474; C04B2111/00612; C04B2111/0062; C04B2111/20; C04B2111/28; Y; Y10; Y10S; Y10S428/00; Y10S428/92; Y10S428/921; Y10T; Y10T428/00; Y10T428/23; Y10T428/232; Y10T428/31504; Y10T428/31971; Y10T428/31989
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
64 words
A gypsum wallboard comprising a set gypsum core and two opposed paper faces, said core comprising, as a major portion, set gypsum, and in minor portions muscovite and short glass fibers, said muscovite being substantially free of feldspar wherein substantially all of said muscovite will pass a 60 mesh screen, said core further comprising minor portions of a set accelerator, starch and foaming agent.
Claim 2
Dependent Claim
64 words
A gypsum wallboard comprising a set gypsum core and two opposed paper faces, said core comprising, as a major portion, set gypsum, and in minor portions muscovite and short glass fibers, said muscovite being substantially free of feldspar wherein substantially all of said muscovite will pass a 60 mesh screen, said core further comprising minor portions of a set accelerator, starch and foaming agent.
Claim 3
Dependent Claim
21 words
A gypsum wallboard as defined by claim 1 wherein said core comprises about 97% set gypsum and about 2% feldspar-free muscovite.
References Cited (Backward Citations)
US2136877A
Cited
US2970127A
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US3189511A
Cited
US3376147A
Cited
US4238546A
Cited
US4403006A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-13 | 1989-07-15 | 1990-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-13 | 1993-07-15 | 1994-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-13 | 1997-07-15 | 1998-01-14 | $7700.00 | Window Closed / Lapsed |