US 12,080,448 B2
Insulated electrical wire and method of manufacturing insulated electrical wire
Hajime Nishi, Tokyo (JP); Ikumi Ando, Tokyo (JP); Takami Ushiwata, Tokyo (JP); and Yuki Honda, Tokyo (JP)
Assigned to Proterial, Ltd., Tokyo (JP)
Filed by PROTERIAL, LTD., Tokyo (JP)
Filed on Sep. 26, 2022, as Appl. No. 17/935,356.
Claims priority of application No. 2021-156780 (JP), filed on Sep. 27, 2021; and application No. 2022-126336 (JP), filed on Aug. 8, 2022.
Prior Publication US 2023/0099568 A1, Mar. 30, 2023
Int. Cl. H01B 7/02 (2006.01); H01B 3/30 (2006.01); H01B 13/06 (2006.01)
CPC H01B 7/0225 (2013.01) [H01B 3/306 (2013.01); H01B 13/06 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An insulated electrical wire comprising:
a conductor; and
an insulating film including pores, wherein
the insulating film at least includes one first insulating layer that is adjacent to the conductor and covers circumference of the conductor,
the first insulating layer includes a first center region, a first inner side region, and a first outer side region,
the first center region is a center region in a thickness direction of the first insulating layer and is formed of an insulating material and first pores that are the pores,
the first inner side region is a region that is closer to the conductor than the first center region in the thickness direction and is formed of an insulating material,
the first outer side region is a region that is opposite to the conductor relative to the first center region in the thickness direction and is formed of an insulating material,
the first pores are derived from a liquid thermally decomposable polymer, and
the first inner side region and the first outer side region are formed not to include the first pores.
 
8. A method of manufacturing an insulated electrical wire, the insulated electrical wire comprising:
a conductor; and
an insulating film including pores,
the insulating film at least including one first insulating layer that is adjacent to the conductor and covers circumference of the conductor,
the first insulating layer including a first center region, a first inner side region, and a first outer side region,
the first center region being a center region in a thickness direction of the first insulating layer and is formed of an insulating material and first pores that are the pores,
the first inner side region being a region that is closer to the conductor than the first center region in the thickness direction and is formed of an insulating material,
the first outer side region being a region that is opposite to the conductor relative to the first center region in the thickness direction and is formed of an insulating material,
the first pores being derived from a liquid thermally decomposable polymer, and
the first inner side region and the first outer side region being formed not to include the first pores,
the method of manufacturing the insulated electrical wire comprising:
a first application step of applying a coating material around a conductor, the coating material containing polyamic acid and a solvent and being obtained by adding a foaming agent composed of a liquid thermally decomposable polymer at a specific part by weight to a resin content of a pre-synthesis coating material and stirring the resulting mixture; and
a first insulating layer forming step of forming the first insulating layer including the first center region, the first inner side region, and the first outer side region by heating the coating material applied around the conductor in the first application step to a specific temperature to remove the solvent in the coating material, imidizing the polyamic acid contained in the coating material in a state in which the thermally decomposable polymer and the polyamic acid are phase-separated, and thermally decomposing the thermally decomposable polymer contained in the coating material.