US4944824A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparation of tooling of carbon fiber reinforced polyimide for composites manufacture
Assignee: Fiberite Inc
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Filing: 1988-09-23
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Granted: 1990-07-31
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Expires: 2008-09-23
Abstract
Abstract Two-stage curing of composite tooling of carbon fiber reinforced polyimide of high Tg.
Inventors
- 👤 Dipak Gupta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:55
CPC Classifications
B; B32; B32B; B32B27/00; C; C08; C08J; C08J3/00; C08J3/24; C08J3/247; B29; B29C; B29C35/00; B29C35/02; B29C35/0227; B29C70/00; B29C70/04; B29C70/28; B29C70/40; B29C70/42; B29C70/44; C08J5/00; C08J5/24; C08J5/241; C08J5/243; B29C2791/00; B29C2791/001; B29C43/00; B29C43/02; B29C43/10; B29C43/12; B29K; B29K2079/00; B29K2307/00; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10T; Y10T428/00; Y10T428/30
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
174 words
A method for preparing a composite tool suitable for fabricating composite articles of high Tg comprising forming a lay-up of prepregs containing carbon fiber reinforcement and substantially stoichiometric quantities of a mixture of diamines consisting essentially of about 95% p-phenylene diamine with the remainder m-phenylene diamine and 2,3-bis-(3',4'-dicarboxyphenyl)hexafluoropropanol in an amount sufficient to produce 35 to 45 volume % of polyimide in the prepreg upon curing, enclosing the lay-up in a vacuum bag, heating the lay-up to a temperature in the range of about 250° to 400° F. while pulling a vacuum on the contents of the bag and while applying a pressure on the bag of at least 180 pounds per square inch, cooling the assembly while releasing the pressure and vacuum, and curing the assembly by heating in an oven to a temperature of at least 700°-725° F. at a rate of 1°-3° F. per minute until the Tg of the composite tool reaches at least 730° F. without application of external pressure but with application of vacuum to remove polymerization byproducts.
Claim 2
Independent Claim
174 words
A method for preparing a composite tool suitable for fabricating composite articles of high Tg comprising forming a lay-up of prepregs containing carbon fiber reinforcement and substantially stoichiometric quantities of a mixture of diamines consisting essentially of about 95% p-phenylene diamine with the remainder m-phenylene diamine and 2,3-bis-(3',4'-dicarboxyphenyl)hexafluoropropanol in an amount sufficient to produce 35 to 45 volume % of polyimide in the prepreg upon curing, enclosing the lay-up in a vacuum bag, heating the lay-up to a temperature in the range of about 250° to 400° F. while pulling a vacuum on the contents of the bag and while applying a pressure on the bag of at least 180 pounds per square inch, cooling the assembly while releasing the pressure and vacuum, and curing the assembly by heating in an oven to a temperature of at least 700°-725° F. at a rate of 1°-3° F. per minute until the Tg of the composite tool reaches at least 730° F. without application of external pressure but with application of vacuum to remove polymerization byproducts.
References Cited (Backward Citations)
US3575756A
Cited
US4336175A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-30 | 1994-01-29 | 1994-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-30 | 1998-01-29 | 1998-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-30 | 2002-01-29 | 2002-07-31 | $7700.00 | Window Closed / Lapsed |