Plaster mold compositions
Abstract
Abstract A COMPOSITION FOR THE MANUFACTURE OF PATTERNS AND MOLDS, PARTICULARLY CERAMIC MOLDS COMPRISING TWO PRINCIPAL CONSTITUENTS: (A) A MIXTURE COMPRISING AN A- AND/OR B-SEMIHYDRATE OF GYPSUM; SODIUM POTASSIUM TARTRATE TO REDUCE EXPANSION AND; CALCIUM HYDROGEN PHOSPHATE TO PROMOTE HARDENING AND CAPILLARITY; AND (B) A MODIFIED MELAMINE FORMALDEHYDE RESIN, E.G., A MELAMINE FORMALDEHYDE RESIN HAVING AT LEAST ONE OR MORE AMINO GROUPS SUBSTITUTED BY A SULFITE OR SULFONIC-ACID GROUP. CONVENTIONAL RETARDERS, ACCELERATORS AND A SECOND HARDENING AGENT SUCH AS FINELYGROUND ANHYDROUS ALUMINUM SULFATE MAY BE PRESENT IN THE MIXTURE. THE COMPOSITION HAS REDUCED EXPANSION ON SETTING WHILE HAVING INCREASED STRENGTH, LIFETIME, EXCELLENT CAPILLARITY AND GAS PERMEABILITY.
Inventors
- 👤 W Reingen
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |