Patent US4354016A successfully refreshed from Google Patents.
US4354016A
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US
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Method of preparing polyesters modified with trihydroxybenzophenone
Assignee: Imperial Chemical Industries Ltd
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Filing: 1980-11-28
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Granted: 1982-10-12
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Expires: 2000-11-28
Abstract
Abstract UV stable linear polyesters, e.g. polyethylene terephthalate, contain in their chain copolymerized 2-hydroxy-di(hydroxyalkoxy)benzophenone. The polyesters are useful for making biaxially oriented films. The polyesters can be made by polycondensation in the presence of 2,4,4'-trihydroxybenzophenone.
Inventors
- 👤 Robert B. Rashbrook
- 👤 Patrick J. Horner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:51
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/66; C08G63/668; C08G63/672
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
73 words
A method of making a linear polyester which has as its repeating unit: --O--Y--O--CO--X--CO-- wherein at least 80 mole % of the X groups represent p-phenylene and the remainder represent m-phenylene and at least 90% of the Y groups represent --CH 2 CH 2 -- and at least 0.1% of the Y groups represent esterification residues of the formula ##STR1## said method comprising polycondensing a glycol terephthalate precursor in the presence of 2,4,4'-trihydroxybenzophenone.
Claim 2
Independent Claim
73 words
A method of making a linear polyester which has as its repeating unit: --O--Y--O--CO--X--CO-- wherein at least 80 mole % of the X groups represent p-phenylene and the remainder represent m-phenylene and at least 90% of the Y groups represent --CH 2 CH 2 -- and at least 0.1% of the Y groups represent esterification residues of the formula ##STR1## said method comprising polycondensing a glycol terephthalate precursor in the presence of 2,4,4'-trihydroxybenzophenone.
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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) | 1985-10-11 | 1986-04-12 | 1986-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-11 | 1990-04-12 | 1990-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-11 | 1994-04-12 | 1994-10-12 | $7700.00 | Window Closed / Lapsed |