Patent US3770468A successfully refreshed from Google Patents.
US3770468A
Expired / Lapsed
US
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Process for treating plaster of paris
Assignee: Knauf Gips KG
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Filing: 1971-05-10
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Granted: 1973-11-06
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Expires: 1991-05-10
Abstract
Abstract A plaster of paris which can be quickly mixed with water to produce a uniform and malleable mortar is produced by spraying powdered burnt plaster of paris with an aqueous solution of a wetting effect material, the amount of water being such that the plaster remains powdered but that the anhydrite III contained in the plaster of paris is converted to the hemihydrate.
Inventors
- 👤 A Schmidt
- 👤 F Wirsching
- 👤 A Knauf
- 👤 P Hartmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:52
CPC Classifications
C; C04; C04B; C04B11/00; C04B11/06; C04B28/00; C04B28/14; C04B28/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
16 words
A process as claimed in claim 1, wherein the said solution contains a retarder of set.
Claim 2
Dependent Claim
14 words
A process as claimed in claim 1, wherein the solution contains a wetting agent.
Claim 3
Dependent Claim
30 words
A process as claimed in claim 1, wherein the plaster of Paris is mixed with an additive selected from expanded perlite, quartz sand, clay, talc, bentonites, vermiculites and limestone gravel.
Claim 4
Dependent Claim
38 words
A process as claimed in claim 1, wherein the amount of water used is such as to increase the content of water of crystallization of said plaster of Paris to a value of from 5 to 6.2 percent.
Claim 5
Dependent Claim
26 words
A process as claimed in claim 1, wherein the solution is used in an amount of about 20 litres per tonne of said plaster of Paris.
Claim 6
Dependent Claim
42 words
A process as claimed in claim 1, wherein the wetting effect material is selected from the group consisting of phosphates, polyphosphates, carboxylic acids having at least four carbon atoms and at least one hydroxy group, ionogenic wetting agents and non-ionogenic wetting agents.
References Cited (Backward Citations)
US3311516A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |