Insulated wire, electrical equipment, and method of producing insulated wire

1. An insulated wire comprising:

a conductor;

a foamed insulating layer containing a thermosetting resin having cells, coated directly or indirectly onto the outer periphery of the conductor; and

an outer insulating layer containing a thermoplastic resin having a melting point of 240° C. or higher in the case where the thermoplastic resin is a crystalline resin or a thermoplastic resin having a glass transition temperature of 240° C. or higher in the case where the thermoplastic resin is a non-crystalline resin, on the outer side of the foamed insulating layer.

2. The insulated wire according to claim 1 , wherein the thermoplastic resin has a storage elastic modulus of 1 GPa or more at 25° C.

3. The insulated wire according to claim 1 , wherein a thickness ratio of the foamed insulating layer to the outer insulating layer (foamed insulating layer/outer insulating layer) is from 5/95 to 95/5.

4. The insulated wire according to claim 1 , wherein the thermoplastic resin comprises a crystalline thermoplastic resin having a melting point of 270° C. or higher.

5. The insulated wire according to claim 1 , used for a motor coil.

6. A method of producing the insulated wire according to claim 1 , comprising the steps of:

forming a foamed insulating layer by applying directly or indirectly a varnish for forming the foamed insulating layer on the outer periphery of a conductor, and by generating foams in the process of baking; and

forming an outer insulating layer by extrusion-molding a thermoplastic resin composition for forming the outer insulating layer on the outer periphery of the foamed insulating layer.

7. Electrical equipment, using the insulated wire according to claim 1 .