US4656235A
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Siloxane-containing polyimide coatings for electronic devices
Assignee: POLYTECHNIC INSTITUTE OF NEW YORK A CORP OF NEW YORK
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Filing: 1985-09-05
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Granted: 1987-04-07
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Expires: 2005-09-05
Abstract
Abstract Siloxane-containing polyimides, useful as conformal coatings for electrical devices, can be synthesized via a novel Diels-Alder reaction in which bis-maleimide derivatives are polymerized with siloxane-containing bis-furan derivatives. The Diels-Alder adduct can be aromatized, and applied as a coating to a mineral substrate. The aromatized, polyimide coating can be cured thermally without additional cyclization on the substrate.
Inventors
- 👤 Giuliana C. Tesoro
- 👤 Vinod R. Sastri
- 👤 Subash C. Narang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:39
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/12; C08F; C08F2/00; C08F2/60
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
112 words
A method for preparing silicon-containing polyimide useful as conformal coatings, comprising polymerizing in a Diels-Alder reaction (a) a reactive diene that is a symmetrical siloxane-containing bis-furan derivative of the general formula: ##STR14## wherein X n is a divalent bridging group linked through position 2 or 3 of the furan rings, where n is 0 or 1, each R', R" and R"' is hydrogen or a hydrocarbon radical of 1 to 6 carbon atoms, and R is a polydimethyl siloxane segment of the general formula: ##STR15## where m is 1-10, and (b) a bis-maleimide dienophile of the general formula: ##STR16## wherein R' is a divalent group of four (4) or more carbon atoms.
Claim 2
Independent Claim
112 words
A method for preparing silicon-containing polyimide useful as conformal coatings, comprising polymerizing in a Diels-Alder reaction (a) a reactive diene that is a symmetrical siloxane-containing bis-furan derivative of the general formula: ##STR14## wherein X n is a divalent bridging group linked through position 2 or 3 of the furan rings, where n is 0 or 1, each R', R" and R"' is hydrogen or a hydrocarbon radical of 1 to 6 carbon atoms, and R is a polydimethyl siloxane segment of the general formula: ##STR15## where m is 1-10, and (b) a bis-maleimide dienophile of the general formula: ##STR16## wherein R' is a divalent group of four (4) or more carbon atoms.
Claim 3
Dependent Claim
15 words
A method for preparing silicon-containing polyimide as recited in claim 1 wherein R' is ##STR17##
Claim 4
Dependent Claim
22 words
A method for preparing silicon-containing polyimide as recited in claim 1, further comprising aromatizing the Diels-Alder adduct by heating in acidic medium.
Claim 5
Dependent Claim
36 words
A method for preparing silicon-containing polyimide as recited in claim 2, wherein said aromatizing and said refluxing of said Diels-Alder adduct is in an acid selected from the group comprising acetic anhydride or glacial acetic acid.
Claim 6
Dependent Claim
34 words
A method for preparing silicon-containing polyimide as recited in claim 1 wherein said polymerizing of said bis-furan and bis-maleimide is by refluxing for 5-10 hours at 60-80 degrees C. in the presence of tetrahydrofuran.
Claim 7
Dependent Claim
22 words
A method for preparing silicon-containing polyimide as recited in claim 5 wherein said refluxing of said bis-furan and bis-maleimide is under nitrogen.
Claim 8
Dependent Claim
179 words
A silicon-containing polyimide useful as a conformal coating and formed as a product of a Diels-Alder reaction comprising the steps of (a) combining a siloxane-containing bis-furan derivative with a bis-maleimide in the presence of an inert solvent wherein the bis-furan derivative is of the general formula: ##STR18## wherein X n is a divalent bridging group linked through position 2 or 3 of the furan rings, where n is 0 or 1, each R', R" and R"' is hydrogen or a hydrocarbon radical of 1 to 6 carbon atoms, and R is a polydimethyl siloxane segment of the general formula: ##STR19## where m is 1-10; (b) polymerizing said mixture by heating in an inert solvent, and (c) aromatizing said polymer by heating in acid to form a polyimide having the general formula: ##STR20## where X n is a divalent bridging group with n is 0 or 1, R is a siloxane segment of the general formula: ##STR21## with m is 1-10, and R' is a divalent group of four or more carbon atoms, or said divalent group containing R units.
Claim 9
Dependent Claim
179 words
A silicon-containing polyimide useful as a conformal coating and formed as a product of a Diels-Alder reaction comprising the steps of (a) combining a siloxane-containing bis-furan derivative with a bis-maleimide in the presence of an inert solvent wherein the bis-furan derivative is of the general formula: ##STR18## wherein X n is a divalent bridging group linked through position 2 or 3 of the furan rings, where n is 0 or 1, each R', R" and R"' is hydrogen or a hydrocarbon radical of 1 to 6 carbon atoms, and R is a polydimethyl siloxane segment of the general formula: ##STR19## where m is 1-10; (b) polymerizing said mixture by heating in an inert solvent, and (c) aromatizing said polymer by heating in acid to form a polyimide having the general formula: ##STR20## where X n is a divalent bridging group with n is 0 or 1, R is a siloxane segment of the general formula: ##STR21## with m is 1-10, and R' is a divalent group of four or more carbon atoms, or said divalent group containing R units.
Claim 10
Dependent Claim
47 words
A silicon-containing polyimide useful as a conformal coating and formed as a product of a Diels-Alder reaction as in claim 7 wherein said polymerizing is conducted by heating in an inert solvent at a temperature of 60-80 degrees C. for 5-7 hours, or until polymerization is completed.
Claim 11
Dependent Claim
41 words
A silicon-containing polyimide useful as a conformal coating and formed as a product of a Diels-Alder reaction as in claim 7 wherein said aromatizing is by refluxing in an acid selected from the group comprising acetic anhydride or glacial acetic acid.
Claim 12
Dependent Claim
89 words
A silicon-containing polyimide useful as a conformal coating and formed as a product of a Diels-Alder reaction as in claim 7, wherein said siloxane containing bis-furan derivative has the general formula: ##STR22## wherein X n is a divalent bridging group linked through position 2 or 3 of the furan rings, where n is 0 or 1, each R', R" and R"' is hydrogen or a hydrocarbon radical of 1 to 6 carbon atoms, and R is a polydimethyl siloxane segment of the general formula: ##STR23## with m is 1-10.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |