US3671486A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filled fusible aromatic prepolymer composition
Assignee: Imperial Chemical Industries Ltd
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Filing: 1970-01-27
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Granted: 1972-06-20
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Expires: 1990-01-27
Abstract
Abstract Mixtures of aromatic tetracarboxylic dianhydrides and/or aromatic tricarboxylic anhydrides and urethane or urea derivatives of aromatic diamines, and soluble and fusible prepolymers obtained therefrom, are useful intermediates for fabricating polyimide articles.
Inventors
- 👤 David Rodney Dixon
- 👤 John Brewster Rose
- 👤 Cecil Nigel Turton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:43
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/14
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
13 words
A prepolymer according to claim 1 in which the filler is glass fiber.
Claim 2
Dependent Claim
13 words
A prepolymer according to claim 1 in which the filler is asbestos fiber.
Claim 3
Dependent Claim
13 words
A prepolymer according to claim 1 in which the filler is carbon fiber.
Claim 4
Dependent Claim
13 words
A prepolymer according to claim 1 in which the filler is metal fiber.
Claim 5
Dependent Claim
43 words
A filled composition comprising a soluble, fusible prepolymer and a solid lubricant as filler, said soluble, fusible prepolymer being the product obtained by heating a mixture of (i) at least one member of the group consisting of an aromatic tetracarboxylic dianhydride of formula
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |