Low dielectric loss tangent resin composition, curable film and cured product, electrical part using the same and method for production thereof

A curable film which contains a crosslinking component having a weight average molecular weight of not more than 1,000 and a plurality of styrene groups and represented by the formula [1]

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• wherein R is a hydrocarbon skeleton which may have a substituent, R1 is hydrogen, methyl or ethyl, m is an integer of 1-4 and n is an integer of 2 or more, and further contains a high polymer having film-forming ability.

An electrical part having an insulator layer wherein the insulator layer contains a cured product of a low dielectric loss tangent resin composition which contains a crosslinking component having a weight average molecular weight of not more than 1,000 and a plurality of styrene groups and represented by the formula [1]

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• wherein R is a hydrocarbon skeleton which may have a substituent, R1 is hydrogen, methyl or ethyl, m is an integer of 1-4 and n is an integer of 2 or more, and further contains at least one member selected from a high plolymer having a weight average molecular weight of not less than 5,000 and a filler.

A method for producing an electrical part having an insulator layer wherein the insulator layer is a curable film containing a low dielectric loss tangent resin composition which contains a crosslinking component having a weight average molecular weight of not more than 1,000 and a plurality of styrene groups and represented by the formula [1]

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• wherein R is a hydrocarbon skeleton which may have a substituent, R1 is hydrogen, methyl or ethyl, m is an integer of 1-4 and n is an integer of 2 or more, and further contains a high polymer having film-forming ability, and the curable film is lamination-bonded onto a conductor layer.