US4226949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wholly aromatic polyamide foam
Assignee: EIDP Inc
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Filing: 1979-08-01
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Granted: 1980-10-07
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Expires: 1999-08-01
Abstract
Abstract Aromatic polyamide foams having a density of 0.025 to 0.7 g./cm.3 are prepared by heating N-alkyl aromatic polyamides having at least one beta hydrogen atom on the alkyl groups, a plasticizer and an aromatic sulfonic acid catalyst at 250 DEG to 340 DEG C. for a length of time sufficient to remove substantially all of the N-alkyl groups.
Inventors
- 👤 Wesley Memeger, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:59
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/02; C08J2377/00; C08J2377/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
65 words
A wholly aromatic polyamide foam prepared by dealkylation of an N-alkyl wholly aromatic polyamide wherein either the diamine residue or the dicarboxylic acid residue is para oriented, said foam having a density of 0.025 to 0.7 g./cm. 3 wherein the cell walls are oriented as evidenced by a birefringence of at least 10% of the maximum possible birefringence and having substantially no residual N-alkyl groups.
Claim 2
Dependent Claim
65 words
A wholly aromatic polyamide foam prepared by dealkylation of an N-alkyl wholly aromatic polyamide wherein either the diamine residue or the dicarboxylic acid residue is para oriented, said foam having a density of 0.025 to 0.7 g./cm. 3 wherein the cell walls are oriented as evidenced by a birefringence of at least 10% of the maximum possible birefringence and having substantially no residual N-alkyl groups.
Claim 3
Dependent Claim
17 words
The foam of claim 1 wherein both the diamine residue and the dicarboxylic acid residue are para-oriented.
Claim 4
Dependent Claim
12 words
The foam of claim 2 wherein the aromatic polyamide is poly(p-phenylene terephthalamide).
Claim 5
Dependent Claim
16 words
The foam of claim 3 wherein the walls of the cells comprising the foam have texture.
References Cited (Backward Citations)
US3770669A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-07 | 1984-04-07 | 1984-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-07 | 1988-04-07 | 1988-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-07 | 1992-04-07 | 1992-10-07 | $7700.00 | Window Closed / Lapsed |