US5115090A
Expired / Lapsed
US
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Viscosity stable, essentially gel-free polyamic acid compositions
Assignee: International Business Machines Corp
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Filing: 1990-03-30
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Granted: 1992-05-19
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Expires: 2010-03-30
Abstract
Abstract Viscosity stable, essentially gel-free linear polyamic acids are provided by a process utilizing offset stoichiometry. Polyimides formed from such polyamic acids have low TCE and low dielectric constants. Methods for improved adhesion of polyimides are also disclosed.
Inventors
- 👤 Krishna G. Sachdev
- 👤 John P. Hummel
- 👤 Ranee W. Kwong
- 👤 Robert N. Lang
- 👤 Leo L. Linehan
- 👤 Harbans S. Sachdev
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:17
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/45; H10W20/48; C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/101; C08G73/1014; H10W70/00; H10W70/60; H10W70/67; H10W70/69; H10W74/00; H10W74/40; H10W74/47; H05; H05K; H05K3/00; H05K3/46; H05K3/4644; H05K3/4673; H05K3/4676
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
58 words
An improved polyamic acid composition comprising the viscosity-stable essentially gel-free reaction product N-methyl-2-pyrrolidone as a solvent with a stoichiometry of 100 mole parts of a linear aromatic diamine with from 97 to 99.5 mole parts of an aromatic dianhydride and a sufficient amount of an aromatic anhydride to react with the residual amine sites and stabilize the composition.
Claim 2
Dependent Claim
58 words
An improved polyamic acid composition comprising the viscosity-stable essentially gel-free reaction product N-methyl-2-pyrrolidone as a solvent with a stoichiometry of 100 mole parts of a linear aromatic diamine with from 97 to 99.5 mole parts of an aromatic dianhydride and a sufficient amount of an aromatic anhydride to react with the residual amine sites and stabilize the composition.
Claim 3
Dependent Claim
27 words
The polyamic acid composition of claim 1 wherein the aromatic diamine is selected from the group consisting of p-phenylene diamine, 4,4'diaminobiphenyl, 2,2'ditrifluoromethyl-4,4'diaminobiphenyl, 4,4"-diaminoterphenyl, ditrifluoromethyl-4,4"-diaminoterphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl and 3,3',5,5'-tetramethyl-4,4'-diaminobiphenyl.
Claim 4
Dependent Claim
23 words
The polyamic acid composition of claim 1 wherein the aromatic dianhydride is selected from the group consisting of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.
Claim 5
Dependent Claim
19 words
The polyamic acid composition of claim 1 wherein the aromatic anhydride is phthalic anhydride or a substituted phthalic anhydride.
Claim 6
Dependent Claim
21 words
The polyamic acid composition of claim 1 wherein the weight average molecular weight is in the range from 20,000 to 50,000.
Claim 7
Dependent Claim
23 words
The polyamic acid composition of claim 1 which further comprises N-methyl-2-pyrrolidone as a solvent and which comprises from about 9 to about 20%.
Claim 8
Dependent Claim
25 words
The polyamic acid composition of claim 1 which comprises the reaction product of 100 mole parts p-phenylene diamine and 98.5 mole parts of 3,3',4,4'biphenyltetracarboxylic dianhydride.
Claim 9
Dependent Claim
50 words
The polyamic acid composition of claim 7 which has intrinsic viscosity in NMP at 25° C. in the range 1.1-1.5 dl/gm, a weight average molecular weight of from 25,000 to 37,000, a solution viscosity of from 2200 to 3000 centistokes and which contains from about 10.5% to about 12.5% solids.
Claim 10
Dependent Claim
23 words
The polyamic acid composition of claim 1 which comprises 100 mole parts phenylene diamine, from 98.8 to 99.5 mole parts of 3,3',4,4'-biphenyltetracarboxylic dianhydride.
Claim 11
Dependent Claim
53 words
The polyamic acid composition of claim 9 which has instrinsic viscosity in NMP at 25° C. in the range 1.1-1.7 dl/gm, a weight average molecular weight from about 32,000 to about 50,000, a solution viscosity of from about 29,000 to about 40,000 centistokes and which has from about 13.5% to about 15.5% solids.
Claim 12
Dependent Claim
14 words
The polyimide formed from the thermal curing of the polyamic acid of claim 1.
Claim 13
Dependent Claim
17 words
The polyimide of claim 11 having a glass transition temperature (Tg) of at least about 390° C.
Claim 14
Dependent Claim
26 words
The polyimide of claim 11 wherein the coefficient of thermal expansion is from about 3 to about 10 parts per million per degree at 100° C.
References Cited (Backward Citations)
CA901701A
Cited
US4959437A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-19 | 1995-11-18 | 1996-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-19 | 1999-11-18 | 2000-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-19 | 2003-11-18 | 2004-05-19 | $7700.00 | Window Closed / Lapsed |