US4849501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyimide coating compositions based on meta-dialkyldihydrogen pyromellitate and aromatic diamines
Assignee: International Business Machines Corp
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Filing: 1988-04-19
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Granted: 1989-07-18
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Expires: 2008-04-19
Abstract
Abstract A composition for the application of a planar polyimide coating having a glass transition temperature above 300° C. comprises a solution in an anhydrous, aprotic solvent of an aromatic diamine and a dialkyldihydrogen pyromellitate which is more than 90% meta isomer.
Inventors
- 👤 Richard D. Diller, deceased
- 👤 Anthony F. Arnold
- 👤 Ying Ying Cheng
- 👤 Patricia M. Cotts
- 👤 Donald C. Hofer
- 👤 Mahmoud Khojasteh
- 👤 Elwood H. Macy
- 👤 Prabodh R. Shah
- 👤 Willi Volksen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:10
CPC Classifications
B; B05; B05D; B05D5/00; B05D5/12; C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1032; C08G73/1067; C08G73/1071; C08L; C08L79/00; C08L79/04; C08L79/08; C09; C09D; C09D179/00; C09D179/04; C09D179/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
44 words
A composition for applying to a substrate a planar polyimide coating having a glass transition temperature over 300° C., said composition comprising a solution in an anhydrous, aprotic solvent of an aromatic diamine and a dialkyldihydrogen pyromellitate which is more than 90% meta isomer.
Claim 2
Dependent Claim
44 words
A composition for applying to a substrate a planar polyimide coating having a glass transition temperature over 300° C., said composition comprising a solution in an anhydrous, aprotic solvent of an aromatic diamine and a dialkyldihydrogen pyromellitate which is more than 90% meta isomer.
Claim 3
Dependent Claim
15 words
A composition as claimed in claim 1 wherein the dialkyldihydrogen pyromellitate is the diethyl compound.
Claim 4
Dependent Claim
16 words
A composition as claimed in claim 1 wherein the aromatic diamine is p-phenylene diamine or 4,4'-diaminodiphenylether.
Claim 5
Dependent Claim
13 words
A composition as claimed in claim 1 wherein the solvent is N-methyl pyrrolidone.
Claim 6
Dependent Claim
17 words
A composition as claimed in claim 4 wherein the solvent also contains about 10% of N-cyclohexyl 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) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |