INSULATING COATING, INSULATED WIRE USING THE INSULATING COATING, AND COIL USING THE INSULATED WIRE

摘要

PROBLEM TO BE SOLVED: To provide an insulating coating which enables formation of a thinner and more homogeneous insulating film while having mechanical properties equivalent to or better than the conventional ones and is excellent in workability including viscosity adjustment, an insulated wire formed with an insulating film using the insulating coating, and a coil using the insulated wire.SOLUTION: An insulating coating is for forming an insulating film. The insulating coating is a solution of a polyamic acid obtained by polymerization reaction of an aromatic tetracarboxylic acid dianhydride, an aromatic diamine, and an acid anhydride having a carboxyl group in the presence of a polar solvent. A ratio of a molar quantity [A] of the mixed aromatic diamine to a molar quantity [B] of the mixed aromatic tetracarboxylic acid dianhydride is 102/100≤[A]/[B]≤105/100. A part of an amino group at the end of the polyamic acid is sealed by the acid anhydride having a carboxyl group.