Patent US3883452A successfully refreshed from Google Patents.
US3883452A
Expired / Lapsed
US
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Composition of polyimide powder and polyformaldehyde
Assignee: EIDP Inc
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Filing: 1973-05-15
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Granted: 1975-05-13
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Expires: 1993-05-15
Abstract
Abstract A composition of a coalescible polyimide powder and a polymer of formaldehyde is provided, said composition adapted for fabricating porous polyimide shaped articles by subjecting said composition to a forming pressure of about 100,000 psi to provide a preform, and thereafter sintering said preform by heating said preform to a temperature above about 300*C. to provide a porous polyimide shaped article having interconnecting pores; said porous polyimide shaped articles being useful as, for example, oil-impregnated bearings.
Inventors
- 👤 Edwin Louis Scheuerlein
- 👤 Jr Frank Clyde Starr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:26
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; C08J9/36; C08J9/40; F; F16; F16C; F16C33/00; F16C33/02; F16C33/04; F16C33/20; F16C33/201; C08J2201/00; C08J2201/04; C08J2201/046; C08J2379/00; C08J2379/04; C08J2379/08
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
39 words
A COMPOSITION COMPRISING A COALESCIBLE POLYIMIDE POWDER AND 5 TO 50% BY WEIGHT, BASED UPON THE TOTAL WEIGHT OF SAID COMPOSITION, OF A SOLID, PARTICULATE HOMOPOLYMER OF FORMALDEHYDE, WHEREIN SAID POLYIMIDE IS CHARACTERIZED BY THE FOLLOWING RECURRING STRUCTURAL UNIT:
Claim 2
Dependent Claim
39 words
A COMPOSITION COMPRISING A COALESCIBLE POLYIMIDE POWDER AND 5 TO 50% BY WEIGHT, BASED UPON THE TOTAL WEIGHT OF SAID COMPOSITION, OF A SOLID, PARTICULATE HOMOPOLYMER OF FORMALDEHYDE, WHEREIN SAID POLYIMIDE IS CHARACTERIZED BY THE FOLLOWING RECURRING STRUCTURAL UNIT:
Claim 3
Dependent Claim
15 words
The composition of claim 1 wherein said solid particulate polymer of formaldehyde is unstabilized polyoxymethylene.
Claim 4
Dependent Claim
12 words
The composition of claim 1 wherein said polymer of formaldehyde is paraformaldehyde.
Claim 5
Dependent Claim
11 words
The article of claim 1 wherein said polyimide is poly-N,N''-(4,4''-oxydiphenylene) pyromellitimide.
Claim 6
Dependent Claim
9 words
The article of claim 4 having present therein graphite.
Claim 7
Dependent Claim
9 words
The article of claim 4 having present therein polytetrafluoroethylene.
Claim 8
Dependent Claim
9 words
The article of claim 5 having present therein polytetrafluoroethylene.
Claim 9
Dependent Claim
24 words
The article of claim 1 wherein said polyimide is a polyimide of 3,3'',4,4''-benzophenone tetracarboxylic dianhydride and an organic diamine having a divalent aromatic radical.
Claim 10
Dependent Claim
9 words
The article of claim 8 having present therein graphite.
Claim 11
Dependent Claim
9 words
The article of claim 8 having present therein polytetrafluoroethylene.
Claim 12
Dependent Claim
9 words
The article of claim 9 having present therein polytetrafluoroethylene.
Claim 13
Dependent Claim
11 words
The article of claim 9 wherein said organic diamine is methaphenylenediamine.
Claim 14
Dependent Claim
11 words
The article of claim 9 wherein said organic diamine is 4,4''-oxydianiline.
Claim 15
Dependent Claim
11 words
The article of claim 10 wherein said organic diamine is metaphenylenediamine.
Claim 16
Dependent Claim
12 words
The article of claim 10 wherein said organic diamine is 4, 4''-oxydianiline.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |