POLYAMIDE-IMIDE RESIN INSULATING VARNISH AND METHOD OF MANUFACTURING THE SAME, INSULATED WIRE AND COIL

1 . A polyamide-imide resin insulating varnish, comprising:

an amic acid-containing amide compound comprising a repeating unit represented by a general formula (1):

where X is a divalent organic group, and R 1 is a divalent organic group derived from a diamine.

2 . The polyamide-imide resin insulating varnish according to claim 1 , wherein the amic acid-containing amide compound further comprises:

an amide compound represented by a general formula (2); and

a diamine component (C) alone or the diamine component (C) and a tetracarboxylic dianhydride (D),

where X is the divalent organic group.

3 . The polyamide-imide resin insulating varnish according to claim 1 , wherein the R 1 is a site including a diamine component (C) and a tetracarboxylic dianhydride (D).

4 . The polyamide-imide resin insulating varnish according to claim 3 , wherein the whole or a part of the diamine component (C) and the tetracarboxylic dianhydride (D) is a compound containing not less than three benzene rings.

5 . A method of manufacturing a polyamide-imide resin insulating varnish, comprising:

blending a tricarboxylic anhydride (A) and a diisocyanate component (B) so as to prepare a mixture; and

adding a diamine component (C) or the diamine component (C) and a tetracarboxylic dianhydride (D) to the mixture so as to react with each other to produce an amic acid-containing compound.

6 . The method according to claim 5 , wherein the blending of the tricarboxylic anhydride (A) and the diisocyanate component (B) is conducted to produce an amide compound represented by a general formula (2):

7 . An insulated wire, comprising:

a conductor; and

an insulation covering formed on the conductor directly or via an other covering thereon,

wherein the insulation covering comprises the polyamide-imide resin insulating varnish according to claim 1 .

8 . A coil comprising the insulated wire according to claim 7 .