US3853813A
Expired / Lapsed
US
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Polyimide precursor and method and composition for preparing it
Assignee: Westinghouse Electric Corp
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Filing: 1973-05-24
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Granted: 1974-12-10
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Expires: 1993-05-24
Abstract
Abstract A composition is disclosed of a dianhydride and a tetracarboxylic acid in the proportions of about 50 to about 70 mole % dianhydride to about 30 to about 50 mole % tetracarboxylic acid, a stoichiometric amount of an aromatic diisocyanate, and a solvent for the dianhydride, the tetracarboxylic acid, and the diisocyanate. A polyimide precursor is prepared by heating the composition at about 30* to 70*C until the evolution of carbon dioxide substantially ceases, and then at about 30* to about 100*C until its viscosity is about Q to about Z6 on the GardnerHoldt viscosity scale at 18% solids. The polyimide precursor can be spread on a substrate and cured to produce a polyimide film or coated on a wire and cured to produce a polyimide wire enamel.
Inventors
- 👤 L Edelman
- 👤 W Alvino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:51
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/30; C08G18/34; C08G18/343; C08G18/346; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1035; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/294
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
9 words
A METHOD OF MAKING A SOLUBLE POLYIMIDE PRECURSOR COMPRISING:
Claim 2
Independent Claim
9 words
A METHOD OF MAKING A SOLUBLE POLYIMIDE PRECURSOR COMPRISING:
Claim 3
Dependent Claim
125 words
PREPARING A COMPOSITION WHICH COMPRISES: (A) A DIANHYDRIDE AND A TETRACARBOXYLIC ACID IN THE PROPORTIONS OF ABOUT 50 TO ABOUT 70 MOLE PERCENT DIANHYDRIDE AND ABOUT 30 TO ABOUT 50 MOLE PERCENT TETRACARBOXYLIC ACID; (B) A STOICHIOMETRIC AMOUNT OF AN AROMATIC DIISOCYANATE; AND (C) A SOLVENT FOR SAID DIANHYDRIDE, SAID TETRACARBOXYLIC ACID, SAID AROMATIC DIISOCYANATE, AND SAID POLYIMIDE PRECURSOR IN AN AMOUNT SUFFICIENT TO MAKE A SOLUTION HAVING A SOLIDS CONTENT OF ABOUT 12 TO ABOUT 25 PERCENT; (2) HEATING SAID COMPOSITION AT ABOUT 30 TO ABOUT 70*C UNTIL THE EVOLUTION OF CARBON DIOXIDE SUBSTANTIALLY CEASES; AND (3) HEATING SAID COMPOSITION AT ABOUT 30 TO ABOUT 100*C UNTIL ITS VISCOSITY IS ABOUT Z TO ABOUT Z6 ON THE GARDNERHOLDT VISCOSITY SCALE AT 18 PERCENT SOLIDS.
Claim 4
Dependent Claim
125 words
PREPARING A COMPOSITION WHICH COMPRISES: (A) A DIANHYDRIDE AND A TETRACARBOXYLIC ACID IN THE PROPORTIONS OF ABOUT 50 TO ABOUT 70 MOLE PERCENT DIANHYDRIDE AND ABOUT 30 TO ABOUT 50 MOLE PERCENT TETRACARBOXYLIC ACID; (B) A STOICHIOMETRIC AMOUNT OF AN AROMATIC DIISOCYANATE; AND (C) A SOLVENT FOR SAID DIANHYDRIDE, SAID TETRACARBOXYLIC ACID, SAID AROMATIC DIISOCYANATE, AND SAID POLYIMIDE PRECURSOR IN AN AMOUNT SUFFICIENT TO MAKE A SOLUTION HAVING A SOLIDS CONTENT OF ABOUT 12 TO ABOUT 25 PERCENT; (2) HEATING SAID COMPOSITION AT ABOUT 30 TO ABOUT 70*C UNTIL THE EVOLUTION OF CARBON DIOXIDE SUBSTANTIALLY CEASES; AND (3) HEATING SAID COMPOSITION AT ABOUT 30 TO ABOUT 100*C UNTIL ITS VISCOSITY IS ABOUT Z TO ABOUT Z6 ON THE GARDNERHOLDT VISCOSITY SCALE AT 18 PERCENT SOLIDS.
Claim 5
Dependent Claim
8 words
a stoichiometric amount of an aromatic diisocyanate; and
Claim 6
Dependent Claim
8 words
a stoichiometric amount of an aromatic diisocyanate; and
Claim 7
Dependent Claim
33 words
A method according to claim 1 wherein the proportion of dianhydride to tetracarboxylic acid is about 60 to about 70 mole % dianhydride and about 30 to about 40 mole % tetracarboxylic acid.
Claim 8
Dependent Claim
28 words
A method according to claim 1 wherein said composition in step (2) is heated at about 40* to about 70*C until the evolution of carbon dioxide substantially ceases.
Claim 9
Dependent Claim
11 words
a solvent for said dianhydride, said tetracarboxylic acid and said diisocyanate.
Claim 10
Dependent Claim
11 words
a solvent for said dianhydride, said tetracarboxylic acid and said diisocyanate.
Claim 11
Dependent Claim
38 words
A method according to claim 1 wherein said composition in step (3) is heated at about 70 to about 90*C until its viscosity is about Z to about Z6 on the Gardner-Holdt viscosity scale at 18 percent solids.
Claim 12
Dependent Claim
15 words
A method according to claim 1 wherein said dianhydride and said tetracarboxylic acid are aromatic.
Claim 13
Dependent Claim
44 words
A method according to claim 5 wherein said dianhydride is selected from the group conSisting of pyromellitic dianhydride, 3,3'',4,4''-benzophenone tetracarboxylic dianhydride, and mixtures thereof, and said tetracarboxylic acid is selected from the group consisting of pyromellitic tetracarboxylic acid, 3,3'',4,4''-benzophenone tetracarboxylic acid, and mixtures thereof.
Claim 14
Dependent Claim
13 words
A method according to claim 1 wherein said aromatic diisocyanate is p, p''-diisocyanatodiphenylether.
Claim 15
Dependent Claim
13 words
A method according to claim 1 wherein said aromatic diisocyanate is p, p''-diisocyanatodiphenylmethane.
Claim 16
Dependent Claim
24 words
A method according to claim 1 wherein after step (3) said composition is spread on a substrate and cured at to form a film.
Claim 17
Dependent Claim
26 words
A method according to claim 1 wherein after step (3) said composition is coated on a paper or fabric and cured to form an insulating sheet.
Claim 18
Dependent Claim
24 words
A method according to claim 1 wherein after step (3) said composition is coated on a wire and cured to form a wire enamel.
Claim 19
Dependent Claim
17 words
A method according to claim 11 wherein said composition is cured at about 275* to about 300*C.
Claim 20
Dependent Claim
30 words
A method according to claim 1 wherein said composition is formed by mixing said dianhydride with said solvent, adding water to form said tetracarboxylic acid, then adding said aromatic diisocyanate.
Claim 21
Dependent Claim
3 words
A composition comprising:
Claim 22
Dependent Claim
3 words
A composition comprising:
Claim 23
Dependent Claim
33 words
A composition according to claim 14 wherein the proportion of dianhydride to tetracarboxylic acid is about 60 to about 70 mole % dianhydride and about 30 to about 40 mole % tetracarboxylic acid.
Claim 24
Dependent Claim
15 words
A composition according to claim 14 wherein said dianhydride and said tetracarboxylic acid are aromatic.
Claim 25
Dependent Claim
44 words
A composition according to claim 16 wherein said dianhydride is selected from the group consisting of pyromellitic dianhydride, 3,3'',4,4''-benzophenone tetracarboxylic dianhydride, and mixtures thereof, and said tetracarboxylic acid is selected from the group consisting of pyromellitic tetracarboxylic acid, 3,3-benzophenone tetracarboxylic acid, and mixtures thereof.
Claim 26
Dependent Claim
14 words
A composition according to claim 14 wherein said aromatic diisocyanate is p, p'' -diisocyanatodiphenylether.
Claim 27
Dependent Claim
14 words
A composition according to claim 14 wherein said aromatic diisocyanate is p, p'' -diisocyanatodiphenylmethane.
Claim 28
Dependent Claim
10 words
An polyimide precursor made according to the method of claim
Claim 29
Dependent Claim
16 words
A polyimide precursor according to claim 20 wherein said dianhydride and said tetracarboxylic acid are aromatic.
Claim 30
Dependent Claim
45 words
A polyimide precursor according to claim 21 wherein said dianhydride is selected from the group consisting of pyromellitic dianhydride, 3,3'',4,4''-benzophenone tetracarboxylic dianhydride, and mixtures thereof, and said tetracarboxylic acid is selected from the group consisting of pyromellitic tetracarboxylic acid, 3,3'',4,4''-benzophenone tetracarboxylic acid, and mixtures thereof.
Claim 31
Dependent Claim
14 words
A polyimide precursor according to claim 20 wherein said aromatic diisocyanate is p,p'' -diisocyanatodiphenylether.
Claim 32
Dependent Claim
13 words
A polyimide precursor according to claim 20 wherein said aromatic diisocyanate is p,p''-diisocyanatodiphenylmethane.
Claim 33
Dependent Claim
27 words
A method according to claim 1 wherein after step (3) said composition is cured at about 100* to about 375*C for about 1 to about 2 hours.
Claim 34
Dependent Claim
24 words
A method according to claim 22 wherein said composition is cured at about 275* to about 300*C for about 1/4 to about 1/2 hour.
Claim 35
Dependent Claim
12 words
A method according to claim 1 wherein said solvent is N-methyl pyrrolidone.
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) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |