US3939109A
Expired / Lapsed
US
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Polyamic-acids prepared from 3,3,4,4-benzhydrol tetracarboxylic dianhydride
Assignee: Chevron USA Inc
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Filing: 1974-12-19
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Granted: 1976-02-17
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Expires: 1994-12-19
Abstract
Abstract A novel polyamic acid intermediate composition in a polar, aprotic solvent and the corresponding fully condensed polyimide are prepared from 3,3',4,4'-benzhydrol tetracarboxylic dianhydride and a diamine having at least two carbon atoms such as bis(4-aminophenyl)ether.
Inventors
- 👤 Walter P. Barie, Jr.
- 👤 Anatoli Onopchenko
- 👤 Johann G. D. Schulz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:50
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1046; C08G73/105; C08G73/1057; C08G73/1064; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31681
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
61 words
A polyamic acid having the general formula ##SPC4## where the carbonyl groups are independently in the 3-, 4- and 3'-, 4'- positions respectively, wherein n is greater than about 10 up to about 1000 and R is a divalent organic radical having at least two carbon atoms with each nitrogen atom chemically bonded to different carbon atoms of said R radical.
Claim 2
Dependent Claim
61 words
A polyamic acid having the general formula ##SPC4## where the carbonyl groups are independently in the 3-, 4- and 3'-, 4'- positions respectively, wherein n is greater than about 10 up to about 1000 and R is a divalent organic radical having at least two carbon atoms with each nitrogen atom chemically bonded to different carbon atoms of said R radical.
Claim 3
Dependent Claim
26 words
A solution containing from about 5 to about 35 weight percent of said polyamic acid of claim 1 and the remainder being a polar, aprotic solvent.
Claim 4
Dependent Claim
26 words
A solution containing from about 15 to about 30 weight percent of the polyamic acid of claim 1 and the remainder being a polar, aprotic solvent.
Claim 5
Dependent Claim
18 words
A polyamic acid in accordance with claim 1 in which n is between about 50 and about 200.
Claim 6
Dependent Claim
53 words
A polyamic acid in accordance with claim 1 in which R is the divalent radical ##SPC5## wherein A is a group selected from --O--, --CO--, --C(R') (R")--, --S--, --SO-- and --SO 2 --, where R' and R" are independently hydrogen or a lower alkyl radical having from one to about four carbon atoms.
Claim 7
Dependent Claim
29 words
A method of preparing the polyamic acid of claim 1 which comprises reacting 3,3',4,4'-benzhydrol tetracarboxylic dianhydride with a diamine at a temperature between about 0° and about 100° C.
Claim 8
Dependent Claim
24 words
A method in accordance with claim 6 in which said reaction is carried out at a temperature between about 20° and about 50° C.
References Cited (Backward Citations)
US3609123A
Cited
US3793291A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-16 | 1979-08-18 | 1980-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-16 | 1983-08-18 | 1984-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-16 | 1987-08-18 | 1988-02-17 | $7700.00 | Window Closed / Lapsed |