Patent US3005103A successfully refreshed from Google Patents.
Patent US3793362A successfully refreshed from Google Patents.
US3793362A
Expired / Lapsed
US
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Reduction of acidic impurities in polymethylene polyphenylisocyanates
Assignee: Pharmacia and Upjohn Co
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Filing: 1971-10-18
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Granted: 1974-02-19
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Expires: 1991-10-18
Abstract
Abstract A PROCESS IS DISCLOSED FOR REDUCING ACIDITY AND HYDROLYZABLE CHLORIDE LEVELS IN POLYMETHYLENE POLYPHENYLSIOCYANATES. THE PROCESS COMPRISES TREATING THE POLYMERIC ISOCYANARE WITH FROM 0.25 TO 1.0 EPOXY EQUIVALENTS OF A MONOMERIX EPOXIDE COMPOUND FOR EACH EQUIVALENT OF ACID PRESENT IN THE ISOCYANATE. THE PROCESS IS PARTICULARLY ADVANTAGEOUS IN THE REDUCTION OF ACID AND HYDROLYZABLE CHLORIDE LEVELS IS OBTAINED WITOUT APPRECIALE INCREASES IN POLYMER VISCOSITY. POLYMETHYLENE POLYPHENYLISOCYANATES TREATED BY THE PROCESS OF THE INVENTION SHOW IMPROVED REACCTIVITY RATES IN THE PREPARATION OF POLYURETHANE AND POLYISOCYANURATE FOAMS, AND RESULT IN FORMS OF IMPROVED STRUCTURE.
Inventors
- 👤 R Kolakowski
- 👤 A Mclaughlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:10
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-18 | 1977-08-20 | 1978-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-18 | 1981-08-20 | 1982-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-18 | 1985-08-20 | 1986-02-19 | $7700.00 | Window Closed / Lapsed |