Enamel resin-insulating laminate, inverter surge-resistant insulated wire using the same and electric/electronic equipment

1. An inverter surge-resistant insulated wire, comprising:

a conductor; and

an enamel resin-insulating laminate that has a foamed region including cells and a non-foamed region including no cells on at least one surface of the foamed region on the conductor,

wherein a porosity of the foamed region in the enamel resin-insulating laminate is 25% or more and 70% or less,

wherein the foamed region is configured such that a non-cell layer including no cells has cell layers having cells on both surface sides of the non-cell layer,

wherein a thickness of each non-cell layer is larger than a thickness of a partition wall among the cells, and 5 to 60% of a thickness of the foamed region,

wherein a thickness ratio t/T is from 0.09 to 0.6 when T is a thickness of the foamed region and t is a thickness of all non-cell layers in the foamed region, and

wherein at least the cell layer in the foamed region is formed of a thermosetting resin.

2. The inverter surge-resistant insulated wire according to claim 1 , wherein a relative dielectric constant at 200° C. of the enamel resin-insulating laminate is 3.0 or less.

3. The inverter surge-resistant insulated wire according to claim 1 , wherein a thickness of the enamel resin-insulating laminate is 40 μm or more, and a thickness of at least one of the non-foamed regions is 10 μm or more.

4. The inverter surge-resistant insulated wire according to claim 1 , wherein a maximum cell diameter of the cells in a thickness direction is less than 20 μm.

5. The inverter surge-resistant insulated wire according to claim 1 , wherein the enamel resin-insulating laminate has a surface layer formed of a resin having a tensile elasticity at 25° C. of 1 GPa or more.

6. The inverter surge-resistant insulated wire according to claim 5 , wherein the surface layer includes at least one kind of thermoplastic resin selected from a polyether ether ketone resin, a thermoplastic polyimide resin, a polyphenylene sulfide resin, a polyesterimide resin and a polyamide resin.

7. The inverter surge-resistant insulated wire according to claim 1 , wherein the foamed region includes at least one kind of thermosetting resin selected from a polyamideimide resin and a polyimide resin.

8. The inverter surge-resistant insulated wire according to claim 1 , wherein the non-foamed region includes at least one kind of thermosetting resin selected from a polyimide resin, a polyamideimide resin, a polyesterimide resin, a polyetherimide resin and a polyimidehydantoin-modified polyester resin.

9. The inverter surge-resistant insulated wire according to claim 1 , wherein the enamel resin-insulating laminate further comprises at least one kind of particles selected from alumina, silica and titania.

10. The inverter surge-resistant insulated wire according to claim 1 , wherein the non-foamed region is formed of a thermoplastic resin and a degree of crystallinity in the non-foamed region formed of the thermoplastic resin is 50% or more.

11. The inverter surge-resistant insulated wire according to claim 1 , wherein the non-foamed region is arranged on a peripheral surface side.

12. Electric/electronic equipment, comprising the inverter surge-resistant insulated wire according to claim 11 .

13. A motor, comprising the inverter surge-resistant insulated wire according to claim 11 .

14. A transformer, comprising the inverter surge-resistant insulated wire according to claim 11 .