US4895972A
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US
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Process for lowering the dielectric constant of polyimides using diamic acid additives
Assignee: National Aeronautics and Space Administration
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Filing: 1988-09-01
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Granted: 1990-01-23
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Expires: 2008-09-01
Abstract
Abstract Linear aromatic polyimides with low dielectric constants are produced by adding a diamic acid additive to the polyamic acid resin formed by the condensation of an aromatic dianhydride with an aromatic diamine. The resulting modified polyimide is a better electrical insulator than state-of-the-art commercially available polyimides.
Inventors
- 👤 Diane M. Stoakley
- 👤 Anne K. St. Clair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:26
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067; C08G73/1003; C08G73/1007; C08G73/1039; C08G73/1046; C08G73/1057; C08G73/1064; C08G73/1071; C08J; C08J5/00; C08J5/18; C08J7/00; C08J7/04; C08J7/044; H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/303; H01B3/306; H01B3/38
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
158 words
A method for producing high temperature linear aromatic polyimide films and coatings having low dielectric constants comprising: forming a polyamic acid solution by chemically reacting equimolar quantities of an aromatic diamine and an aromatic dianhydride in a solvent medium; adding a diamic acid additive to the polyamic acid solution so that the concentration of the diamic acid additive is about 1-20 percent by weight based on the percent solids in the polyamic acid resin, the diamic acid additive being selected from the group consisting of: 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride-aniline diamic acid; 3,3,'-diaminodiphenylsulfone-phthalic anhydride diamic acid; 4,4,'-oxydiphthalic anhydride-aniline diamic acid; 2,2-bis[4(4-aminophenoxy)phenyl]hexafluoropropane-phthalic anhydride diamic acid; 2,2-bis[4(3-aminophenoxy)phenyl]hexafluoropropane-phthalic anhydride diamic acid; and 4,4'-oxydianiline-phthalic anhydride diamic acid; applying onto a surface a desired thickness film layer of the polyamic acid solution containing the diamic acid additive; and thermally curing the applied film in the temperature range of 250° C. to 300° C. for at least one hour to yield a low dielectric polyimide film layer.
Claim 2
Independent Claim
158 words
A method for producing high temperature linear aromatic polyimide films and coatings having low dielectric constants comprising: forming a polyamic acid solution by chemically reacting equimolar quantities of an aromatic diamine and an aromatic dianhydride in a solvent medium; adding a diamic acid additive to the polyamic acid solution so that the concentration of the diamic acid additive is about 1-20 percent by weight based on the percent solids in the polyamic acid resin, the diamic acid additive being selected from the group consisting of: 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride-aniline diamic acid; 3,3,'-diaminodiphenylsulfone-phthalic anhydride diamic acid; 4,4,'-oxydiphthalic anhydride-aniline diamic acid; 2,2-bis[4(4-aminophenoxy)phenyl]hexafluoropropane-phthalic anhydride diamic acid; 2,2-bis[4(3-aminophenoxy)phenyl]hexafluoropropane-phthalic anhydride diamic acid; and 4,4'-oxydianiline-phthalic anhydride diamic acid; applying onto a surface a desired thickness film layer of the polyamic acid solution containing the diamic acid additive; and thermally curing the applied film in the temperature range of 250° C. to 300° C. for at least one hour to yield a low dielectric polyimide film layer.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein the aromatic diamine is selected from the group of diamines consisting of: 3,3'-, 3,4'-, or 4,4'-oxydianiline; 3,3'-, 3,4'-, or 4,4'-diaminobenzophenone; 3,3'-, 3,4'-, or 4,4'-diaminodiphenylmethane; meta- or, para-phenylenediamine; 3,3'-, 3,4'-, or 4,4'-diaminodiphenylsulfone; 2,2-bis[4(4-aminophenoxy)phenyl]hexafluoropropane; 2,2-bis[4(3-aminophenoxy)phenyl]hexafluoropropane.
Claim 4
Dependent Claim
33 words
The method of claim 1 wherein the dianhydride is selected from the group of aromatic dianhydrides consisting pyromellitic dianhydride; 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride; 4,4'-oxydiphthalic anhydride; 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride; 3,3',4,4'-benzophenone tetracarboxylic dianhydride; and 3,4,3',4'-biphenyltetracarboxylic dianhydride.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the solvent is selected from the group consisting of: N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, and bis(2-methoxyethyl)ether.
Claim 6
Dependent Claim
27 words
The method of claim 1 wherein the concentration of diamic acid additive is 3-15 percent by weight based on the percent solids in the polyamic acid resin.
Claim 7
Dependent Claim
20 words
The method of claim 1 wherein the diamine is selected from the group of diamines consisting of: 4,4'-oxydianiline; and 2,2-bis[4(4-aminophenoxy)phenyl]hexafluoropropane.
Claim 8
Dependent Claim
24 words
The method of claim 1 wherein the dianhydride is selected from the group of aromatic dianhydrides consisting of: pyromellitic dianhydride; 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein the polyamic acid resin is selected from the group consisting of: 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride/2,2-bis[4(4-aminophenoxy)phenyl]hexafluoropropane; and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4(4-aminophenoxy)phenyl]hexafluoropropane; and pyromellitic dianhydride/4,4'-oxydianiline.
Claim 10
Dependent Claim
10 words
The method of claim 1 wherein the solvent is N,N-dimethylacetamide.
References Cited (Backward Citations)
No citation records indexed.
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