Siloxane-containing polyimide coatings for electronic devices
AssigneePolytechnic Institute of New York
InventorsGiuliana C. Tesoro, Vinod R. Sastri, Subash C. Narang
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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.
Claims10
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.sub.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.
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.sub.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.sub.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.
Dependencies are inferred from the claim text.