Patent ID: 8741441

Claim:
An insulated wire, comprising: a conductor; and an insulating covering layer formed on the periphery of the conductor and comprising two or more insulating coatings, wherein the insulating covering layer comprises a first insulating coating formed on the periphery of the conductor and a second insulating coating formed on the periphery of the first insulating coating, wherein the first insulating coating consists of a polyamide-imide resin material synthesized by reacting at least one of the group consisting of 4,4′-diphenylmethane diisocyanate (4,4′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI) and 4,4′-diphenyl ether diisocyanate with trimellitic anhydride (TMA), the first insulating coating formed by applying to the periphery of the conductor and baking the polyamide-imide resin insulating material, the second insulating coating consists of a polyamide-imide resin insulating material obtained by reacting an imide group containing dicarboxylic acid with a diisocyanate, the imide group containing dicarboxylic acid being obtained by dehydration reaction of a diamine component consisting of at least one divalent aromatic diamine including three or more aromatic rings selected from the group consisting of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]ether, and 1,4-bis(4-aminophenoxy)benzene with TMA or benzophenone tricarboxylic acid as an acid using a solvent and the diisocyanate being at least one of the group consisting of 4,4′-diphenylmethane diisocyanate (MDI), 2,2-bis[4-(4-isocyanatephenoxy)phenyl]propane (BIPP), tolylene diisocyanate (TDI), xylylene diisocyanate, diphenyl sulfone diisocyanate and diphenyl ether diisocyanate, and the second insulating coating formed by applying to the periphery of the first insulating coating and baking the polyamide-imide resin insulating material, and wherein the insulating covering layer has a relative dielectric constant of 3 or less.