US4169747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composition for accelerating the setting of calcined gypsum and the product formed thereby
Assignee: United States Gypsum Co
•
Filing: 1977-06-06
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Granted: 1979-10-02
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Expires: 1997-06-06
Abstract
Abstract A composition for accelerating the setting of an aqueous calcined gypsum slurry, the composition comprising finely ground calcium sulfate dihydrate and a lignosulfonate. The composition, when added to an aqueous calcined gypsum slurry, accelerates the setting process and shortens the set time period as determined by the temperature rise set test procedure. The composition is useful for making gypsum wallboard.
Inventors
- 👤 Felix J. De Rooy
- 👤 Thell D. Daniel
- 👤 Erle C. Annes
- 👤 Billy G. Arnold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:22
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/14
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A method of making gypsum wallboard, comprising (a) forming a dry accelerator composition by grinding together calcium sulfate dihydrate and a lignosulfonate to fine particle size, said lignosulfonate being present in an amount from about 0.5% to about 99% by weight of said composition, (b) mixing a minor proportion of said acclerator composition and a major proportion of calcium sulfate hemihydrate with water to form an aqueous slurry, (c) depositing said slurry on a surface and permitting said slurry to set, and drying the gypsum wallboard formed thereby.
Claim 2
Independent Claim
88 words
A method of making gypsum wallboard, comprising (a) forming a dry accelerator composition by grinding together calcium sulfate dihydrate and a lignosulfonate to fine particle size, said lignosulfonate being present in an amount from about 0.5% to about 99% by weight of said composition, (b) mixing a minor proportion of said acclerator composition and a major proportion of calcium sulfate hemihydrate with water to form an aqueous slurry, (c) depositing said slurry on a surface and permitting said slurry to set, and drying the gypsum wallboard formed thereby.
Claim 3
Dependent Claim
15 words
A method according to claim 1, wherein said lignosulfonate has a wood sugar associated therewith.
Claim 4
Dependent Claim
34 words
A method according to claim 2, wherein the particles of said composition have a surface area of from about 5,000 to about 20,000 square centimeters per gram as determined by a Fisher Sub-sieve Sizer.
Claim 5
Dependent Claim
30 words
A method according to claim 2, wherein the total amount of said lignosulfonate and associated wood sugar is from about 3% to about 75% by weight of said accelerator composition.
Claim 6
Dependent Claim
12 words
A method according to claim 2, wherein said lignosulfonate is ammonium lignosulfonate.
Claim 7
Dependent Claim
12 words
A method according to claim 2, wherein said lignosulfonate is sodium lignosulfonate.
Claim 8
Dependent Claim
12 words
A method according to claim 2, wherein said lignosulfonate is calcium lignosulfonate.
Claim 9
Dependent Claim
14 words
A method according to claim 2, wherein said lignosulfonate is in the acid form.
Claim 10
Dependent Claim
28 words
A method according to claim 2, wherein the amount of said lignosulfonate and associated wood sugar is from about 5% to about 50% by weight of said composition.
Claim 11
Dependent Claim
14 words
A method according to claim 2, wherein said lignosulfonate is in the solid state.
Claim 12
Dependent Claim
27 words
A method according to claim 2, wherein the amount by weight of said accelerator composition is from about 0.01% to about 1.5% of said dry calcined gypsum.
Claim 13
Dependent Claim
27 words
A method according to claim 2, wherein the amount by weight of said accelerator composition is from about 0.15% to about 1.5% of said dry calcined gypsum.
References Cited (Backward Citations)
US2078198A
Cited
US2856304A
Cited
US2957774A
Cited
US3053673A
Cited
US3108008A
Cited
US3573947A
Cited
US3813312A
Cited
US3723145A
Cited
US3772045A
Cited
US3725090A
Cited
US3864141A
Cited
US3870538A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-01 | 1983-04-02 | 1983-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-01 | 1987-04-02 | 1987-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-01 | 1991-04-02 | 1991-10-02 | $7700.00 | Window Closed / Lapsed |