US4524171A
Expired / Lapsed
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Preparation of an aromatic polyimide acid by solution polymerization using propylene glycol methyl ether
Assignee: Chevron USA Inc
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Filing: 1984-08-20
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Granted: 1985-06-18
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Expires: 2004-08-20
Abstract
Abstract A one-step solution technique for preparing an aromatic polyimide acid which comprises reacting an aromatic dianhydride with an aromatic diamine in the presence of propylene glycol methyl ether.
Inventors
- 👤 Kiran R. Bakshi
- 👤 Walter P. Barie
- 👤 Edward T. Sabourin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:08
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1032; C08G73/1067
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
37 words
A method for preparing a solution of an aromatic polyimide acid which comprises: reacting an aromatic dianhydride with an approximately equimolar quantity of an aromatic diamine in the presence of a solvent comprising propylene glycol methyl ether.
Claim 2
Independent Claim
37 words
A method for preparing a solution of an aromatic polyimide acid which comprises: reacting an aromatic dianhydride with an approximately equimolar quantity of an aromatic diamine in the presence of a solvent comprising propylene glycol methyl ether.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein the dianhydride has the formula: ##STR7## where Z is selected from the group consisting of --0-- and ##STR8##
Claim 4
Dependent Claim
16 words
A method according to claim 2 wherein the dianhydride is 3,3', 4,4', benzophenone tetracarboxcyclic acid dianhydride.
Claim 5
Dependent Claim
26 words
A method according to claim 1 wherein the aromatic diamine has the formula: ##STR9## where Z is selected from the group consisting of --O-- and ##STR10##
Claim 6
Dependent Claim
13 words
A method according to claim 4 wherein the aromatic diamine is meta, meta'-diaminobenzophenone.
Claim 7
Dependent Claim
43 words
A method according to claim 1 wherein the aromatic dianhydride is added to a slurry of the aromatic diamine and the solvent at a rate such that the temperature of reaction is maintained at a temperature below the temperature where imidization would occur.
Claim 8
Dependent Claim
18 words
A method according to claim 6 wherein the reaction temperature is maintained at less than about 40° C.
Claim 9
Dependent Claim
28 words
A method in accordance with claim 1 wherein the weight percent of the propylene glycol methyl ether is from 65 to 90 weight percent of the reaction mixture.
Claim 10
Dependent Claim
24 words
A method in accordance with claim 1 wherein the molar ratio of said dianhydride to said diamine is from about 0.95:1 to about 1.05:1.
References Cited (Backward Citations)
US4065345A
Cited
US4115341A
Cited
US4181641A
Cited
US4255471A
Cited
US4332708A
Cited
US4382126A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-17 | 1988-12-17 | 1989-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-17 | 1992-12-17 | 1993-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-17 | 1996-12-17 | 1997-06-18 | $7700.00 | Window Closed / Lapsed |