US3644571A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of heating caprolactam graft copolymers to increase melt strength
Assignee: Gulf Research and Development Co
•
Filing: 1970-03-19
•
Granted: 1972-02-22
•
Expires: 1990-03-19
Abstract
Abstract WHEN OLEFIN-MALEIC ANHYDRIDE COPOLYMERS ARE EMPLOYED AT LOW LEVELS IN HYDROLYTIC POLYMERIZATION OF CAPROLACTAM TO YIELD GRAFTED CAPROLACTAM COPOLYMERS, THE RESULTING POLYMERS UPON HEATING IN THE SOLID STATE AT A TEMPERATURE OF AT LEAST 140*C. INCREASE IN MELT STRENGTH TO VALUES CONSIDERABLY ABOVE THE MELT STRENGTH OF CONVENTIONAL POLYCAPROLACTAM OF EQUIVALENT MELT INDEX. THE RESULTING PRODUCTS HAVING HIGH MELT STRENGTH MAY BE ADVANTAGEOUSLY USED FOR THE MANUFACTURE OF EXTRUDED AND BLOV XXX OLDED ARTICLES.
Inventors
- 👤 Raymond P Anderson
- 👤 Francis R Galiano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:15
CPC Classifications
C; C08; C08L; C08L77/00; C08L77/02; C08F; C08F8/00
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1975-02-21 | 1975-08-23 | 1976-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-21 | 1979-08-23 | 1980-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-21 | 1983-08-23 | 1984-02-22 | $7700.00 | Window Closed / Lapsed |