Patent US4020237A successfully refreshed from Google Patents.
US4020237A
Expired / Lapsed
US
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Paper covered gypsum board and process of manufacture
Assignee: United States Gypsum Co
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Filing: 1975-09-22
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Granted: 1977-04-26
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Expires: 1995-09-22
Abstract
Abstract A paper covered gypsum board and a process for its manufacture, with at least one cover of the board comprising a multiply paper sheet containing a major proportion of cellulosic fibers and a minor proportion of short mineral fibers.
Inventors
- 👤 Romulis S. von Hazmburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:29
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/043; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31971; Y10T428/31975; Y10T428/31978; Y10T428/31982; Y10T428/31993; Y10T428/31996
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
81 words
A gypsum board comprising a core of cast gypsum and having a porous paper cover sheet formed of a plurality of plies, said paper cover sheet consisting of essentially of a major proportion of cellulosic fibers and a minor proportion of mineral fibers in an amount of from about 2 to 20% by weight of said paper cover sheet with the amount of mineral fibers in any one ply of said paper cover sheet not exceeding about 43% by weight thereof.
Claim 2
Dependent Claim
81 words
A gypsum board comprising a core of cast gypsum and having a porous paper cover sheet formed of a plurality of plies, said paper cover sheet consisting of essentially of a major proportion of cellulosic fibers and a minor proportion of mineral fibers in an amount of from about 2 to 20% by weight of said paper cover sheet with the amount of mineral fibers in any one ply of said paper cover sheet not exceeding about 43% by weight thereof.
Claim 3
Dependent Claim
27 words
A gypsum board in accordance with claim 1 wherein a ply of said cover sheet containing said mineral fibers is in contact with the cast gypsum core.
Claim 4
Dependent Claim
56 words
A gypsum board in accordance with claim 1 having a multiply paper cover sheet containing in a plurality of plies thereof mineral fibers in an amount from about 2 to 20% by weight of said paper cover sheet with the amount of said mineral fibers in any one ply not exceeding about 43% by weight thereof.
Claim 5
Dependent Claim
80 words
A gypsum board comprising a core of cast gypsum having face and back porous paper cover sheets therefor, each of said sheets being formed of a plurality of plies and consisting essentially of a major proportion of cellulosic fibers and a minor proportion of mineral fibers in an amount from about 2 to 20% by weight of each of said paper cover sheets with the amount of mineral fibers in any one ply not exceeding about 43% by weight thereof.
Claim 6
Dependent Claim
80 words
A gypsum board comprising a core of cast gypsum having face and back porous paper cover sheets therefor, each of said sheets being formed of a plurality of plies and consisting essentially of a major proportion of cellulosic fibers and a minor proportion of mineral fibers in an amount from about 2 to 20% by weight of each of said paper cover sheets with the amount of mineral fibers in any one ply not exceeding about 43% by weight thereof.
Claim 7
Dependent Claim
26 words
A gypsum board in accordance with claim 4 wherein said plies of said cover sheets containing mineral fibers are in contact with the cast gypsum core.
Claim 8
Dependent Claim
69 words
A gypsum board in accordance with claim 4 containing mineral fibers in a plurality of plies of each of said back and face cover sheets, the mineral fibers being employed in an amount from about 2 to 20% by weight of each of said paper cover sheets with the amount of mineral fibers in any one ply of said paper cover sheets not exceeding about 43% by weight thereof.
Claim 9
Dependent Claim
33 words
A gypsum board in accordance with claim 4 wherein the exposed surface ply of each of said face and back cover sheets contains less mineral fiber than other plies of said cover sheets.
Claim 10
Dependent Claim
26 words
A gypsum board in accordance with claim 7 wherein the exposed surface plies of said face and back cover sheets are substantially free of mineral fiber.
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) | 1980-04-25 | 1980-10-25 | 1981-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-25 | 1984-10-25 | 1985-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-25 | 1988-10-25 | 1989-04-26 | $7700.00 | Window Closed / Lapsed |