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US4526619A
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Gypsum composition for denture investment
Assignee: GC Corp
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Filing: 1983-07-22
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Granted: 1985-07-02
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Expires: 2003-07-22
Abstract
Abstract A gypsum composition for denture investment consists of 100 parts by weight of a mixture of 50-90 parts by weight of alpha -Gypsum hemihydrate ( alpha -CaSO4.1/2H2O) with 10-50 parts by weight of beta -Gypsum hemihydrate ( beta -CaSO4.1/2H2O) and 0.2-2.0 parts by weight of a soluble potassium salt. As the soluble potassium salt, use may be made of one or more of potassium sulfate, potassium chloride and potassium tartrate. The gypsum composition may further include 0.5-5.0 parts by weight of dihydrate gypsum.
Inventors
- 👤 Nobukazu Ohi
- 👤 Koji Ohno
- 👤 Satoshi Tosaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:17
CPC Classifications
C; C04; C04B; C04B11/00; C04B11/002; A; A61; A61K; A61K6/00; A61K6/80; A61K6/849; A61K6/858; C04B28/00; C04B28/14; C04B28/145; C04B28/147; C04B2111/00; C04B2111/00474; C04B2111/00836; C04B2111/00939
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
57 words
A gypsum composition for denture investment consisting of 100 parts by weight of a mixture of 50-90 parts by weight of α-Gypsum hemihydrate (α-CaSO 4 .1/2H 2 O), 10-50 parts by weight of β-Gypsum hemihydrate (β-CaSO 4 .1/2H 2 O), 0.2-2.0 parts by weight of a soluble potassium salt, and 0.5-5.0 parts by weight of gypsum dihydrate.
Claim 2
Dependent Claim
57 words
A gypsum composition for denture investment consisting of 100 parts by weight of a mixture of 50-90 parts by weight of α-Gypsum hemihydrate (α-CaSO 4 .1/2H 2 O), 10-50 parts by weight of β-Gypsum hemihydrate (β-CaSO 4 .1/2H 2 O), 0.2-2.0 parts by weight of a soluble potassium salt, and 0.5-5.0 parts by weight of gypsum dihydrate.
Claim 3
Dependent Claim
28 words
A gypsum composition as recited in claim 1, wherein the potassium salt is selected from the group consisting of potassium sulfate, potassium chloride, potassium tartrate and mixtures thereof.
Claim 4
Dependent Claim
24 words
A gypsum composition as recited in claim 1 or 2, in which the gypsum dihydrate contains up to 0.7% by weight of free water.
References Cited (Backward Citations)
US3305375A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |