Patent US3728416A successfully refreshed from Google Patents.
US3728416A
Expired / Lapsed
US
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Process for producing high softening, non-crystalline condensation copolymers
Assignee: Eastman Kodak Co
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Filing: 1971-08-25
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Granted: 1973-04-17
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Expires: 1991-08-25
Abstract
Abstract An improved process for the preparation of copolymers from a copolymer derived from terephthalic acid, isophthalic acid and Bisphenol A and a homopolymer derived from isophthalic acid and Bisphenol A by extruding a molten mixture of the copolymer and the homopolymer whereby copolymerization of the two p9lymers occurs in situ to produce a randomized copolymer. The process is thus useful in the production of a copolymer product which finds application in the production of fibers, films, sheets, molded objects and other products.
Inventors
- 👤 G Akin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:48
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/12; C08G63/16; C08G63/18; C08G63/19; C08G63/193; C08G63/195; C08L; C08L67/00; C08L67/02; C08L67/03
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
67 words
The process of claim 1 in which there is employed about 100 parts by weight of the said copolymer (1) which is composed of approximately 70 mole percent terephthalic acid, approximately 30 mole percent of isophthalic acid and 100 mole percent of Bisphenol A, and about 40 parts by weight of the homopolymer (2) which is composed of equal mole proportions of isophthalic acid and Bisphenol A.
Claim 2
Dependent Claim
39 words
The process of claim 2 in which the mixture of copolymer and homopolymer is melted by subjecting the mixture to said temperature of 350*C.-390*C. while in contact with at least half the length of the screw of the extruder.
Claim 3
Dependent Claim
21 words
ThE process of claim 3 in which the residence time of the polymer mixture in the extruder is about 5 minutes.
References Cited (Backward Citations)
US3228997A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |