Patent ID: 8466251

Claim:
A polyamide-imide resin insulating paint, including a low permittivity polyamide-imide resin containing no halogen element in its molecular chain which is dissolved in a polar solvent, wherein: the low permittivity polyamide-imide resin contains an aromatic diisocyanate component (A) consisting of an aromatic isocyanate having three or more benzene rings in a monomer, an aromatic diisocyanate component (B) consisting of an aromatic isocyanate having two or less benzene rings in a monomer, and an acid component which consists of an aromatic tricarboxylic anhydride (C) alone or comprises both the aromatic tricarboxylic anhydride (C) and an aromatic tetracarboxylic dianhydride (D) simultaneously, having a compounding ratio between A and C or among A, C and D of A/(C+D)=50/100 to 70/100, and a ratio M/N between a molecular weight (M) of the polyamide-imide resin per repeat unit and an average number (N) of amide groups and imide groups is equal to or more than 200.