US5162492A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrolytically and oxidatively stable polyimides
Assignee: L'Oréal SA
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Filing: 1990-10-11
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Granted: 1992-11-10
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Expires: 2010-10-11
Abstract
Abstract Polyimide prepared from 3,3'4,4'-biphenyltetracarboxylic dianhydride and an aromatic diamine which is at least about 60% meta-phenylene diamine exhibits excellent hydrolytic and oxidative stability.
Inventors
- 👤 Mureo Kaku
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:41
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067; C08K; C08K3/00; C08K3/02; C08K3/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
44 words
A substantially amorphous, solid particulate polyimide having the recurring unit ##STR3## wherein R is at least about 60% meta-phenylene units and up to about 40% para-phenylene units, the particles of polyimide having a surface area of greater than about 15 square meters per gram.
Claim 2
Dependent Claim
44 words
A substantially amorphous, solid particulate polyimide having the recurring unit ##STR3## wherein R is at least about 60% meta-phenylene units and up to about 40% para-phenylene units, the particles of polyimide having a surface area of greater than about 15 square meters per gram.
Claim 3
Dependent Claim
14 words
A polyimide of claim 1 wherein R is at least about 75% metaphenylene units.
Claim 4
Dependent Claim
12 words
A polyimide of claim 2 wherein R consists essentially of meta-phenylene units.
Claim 5
Dependent Claim
12 words
A polyimide of claim 1 further comprising at least about 1% filler
Claim 6
Dependent Claim
12 words
A polyimide of claim 4 wherein the filler is in particulate form.
Claim 7
Dependent Claim
12 words
A polyimide of claim 4 wherein the filler consists essentially of graphite.
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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) | 1995-11-10 | 1996-05-11 | 1996-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-10 | 2000-05-11 | 2000-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-10 | 2004-05-11 | 2004-11-10 | $7700.00 | Window Closed / Lapsed |