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US3965236A
Expired / Lapsed
US
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Poly(meta-phenylene isophthalamide) powder and process
Assignee: EIDP Inc
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Filing: 1975-02-24
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Granted: 1976-06-22
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Expires: 1995-02-24
Abstract
Abstract A poly(meta-phenylene isophthalamide) powder is provided which is coalescible under the influence of pressure followed by heating at temperatures below its crystalline melting point to provide molded objects of a solid and homogeneous nature. A process for preparing coalescible powders of poly(meta-phenylene isophthalamide) also is provided wherein a solution of said polymer in a solvent such as DMAC is added to a precipitant such as water to provide a slurry which is filtered, followed by washing and drying the resulting filter cake to provide a crumb which is ground and screened through a sieve of 35 mesh size (U.S. Standard).
Inventors
- 👤 John William Turnbull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:43
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J3/14; B; B29; B29C; B29C43/00; B29C43/003; B29C43/006; B29K; B29K2077/00; B29K2077/10; B29K2105/00; B29K2105/25; B29K2105/251; C08J2377/00; C08J2377/10
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
102 words
A process for fabricating shaped articles from a coalescible and densifiable powder of poly(meta-phenylene isophthalamide) having a bulk density between about 0.02 g./cc. and about 0.4 g./cc. which comprises pressing said powder by subjecting said powder to a forming pressure of at least 10,000 psi. at a temperature up to about 250°C. to provide a preform having a density between about 1.0 g./cc. and about 1.30 g./cc., and sintering said preform by heating said preform in an inert atmosphere to a temperature between about 250°C. and about 350°C. to provide a shaped article having a density of at least about 1.24 g./cc.
Claim 2
Dependent Claim
102 words
A process for fabricating shaped articles from a coalescible and densifiable powder of poly(meta-phenylene isophthalamide) having a bulk density between about 0.02 g./cc. and about 0.4 g./cc. which comprises pressing said powder by subjecting said powder to a forming pressure of at least 10,000 psi. at a temperature up to about 250°C. to provide a preform having a density between about 1.0 g./cc. and about 1.30 g./cc., and sintering said preform by heating said preform in an inert atmosphere to a temperature between about 250°C. and about 350°C. to provide a shaped article having a density of at least about 1.24 g./cc.
Claim 3
Dependent Claim
41 words
The process of claim 1 wherein said preform is sintered by subjecting said preform to a heating cycle including heating said preform up to a temperature of 250°C., followed by heating said preform to a temperature between about 260°C. and 320°C.
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) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |