Patent US3640981A successfully refreshed from Google Patents.
US3640981A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vinyl toluene-alpha methyl styrene co-polymers and method of preparing the same
Assignee: Reichhold Chemicals Inc
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Filing: 1969-04-23
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Granted: 1972-02-08
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Expires: 1989-04-23
Abstract
Abstract COPOLYMERS OF ALPHA METHYL STYRENE AND VINYL TOLUENE ARE PREPARED BY POLYMERIZING SAID MONOMERS IN PRESENCE OF PHOSPHORUS PENTAFLUORIDE AS A CATALYST IN AN AROMATIC DILUENT OR IN A BLEND OF AROMATIC AND ALIPHATIC DIIUENTS. IN ADDITION TRIPHENYL PHOSPHITE IS EMPLOYED TO PROTECT THE COPOLYMER DURING STRIPPING. SAID METHOD RESULTS IN CLEAR RESINS GIVING WATER WHILE SOLUTIONS IN MINERAL SPIRITS, WHICH ARE ODORLESS AND SUBSTANTIALLY FREE FROM AROMATICS.
Inventors
- 👤 Bernard J Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:55
CPC Classifications
C; C08; C08F; C08F212/00; C08F212/02; C08F212/04; C08F212/06; C08F212/12
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) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |