Conventionally, a round wire or a rectangular wire is employed as an insulated wire (magnet wire) used for a stator of an electric generator (motor generator) installed in automobiles. By employing a rectangular wire, a fill factor of the stator can be increased as compared to a case where a conductor having a generally round cross section is employed, and thus an electric generator having a reduced size and a higher power can be obtained. Recently, along with electric generators having a reduced size and higher power as described above, an insulated wire of the generator for vehicles is required to have properties, such as an insulating property, resistance to thermal softening, flexibility, and a long-term heat resistance, which are improved as compared to those of a conventional configuration.

By forming a single or a plurality of thermoplastic resin layers on an enamel layer and specifying the range/ranges of relative crystallinity of the thermoplastic resin layer/layers formed on the enamel layer, adhesion between insulating layers and prevention of occurrence of a crack can be achieved together, and that, further, an excellent ATF-resistant property can be obtained. 

(1) A rectangular insulated wire comprising:
a rectangular conductor having a generally rectangular cross section; a thermosetting resin layer provided to cover the rectangular conductor; and a plurality of thermoplastic resin layers provided on the thermosetting resin layer,man adhesion strength between the thermosetting resin layer and the thermoplastic resin layer being 50 gf/mm to 100 gf/mm.
(2) The rectangular insulated wire according to the aforementioned statement (1), wherein the thermoplastic resin layer is a crystalline resin layer formed of any of materials selected from the group comprising polyetheretherketone, polyetherketoneketone, polyetherketone, polyphenylene sulfide and thermoplastic polyimide.
(3) The rectangular insulated wire according to the aforementioned statements (1) or (2), wherein adhesion strengths between the plurality of thermoplastic resin layers are 50 gf/mm to 100 gf/mm, respectively.
(4) The rectangular insulated wire according to any one of the aforementioned statements (1) to (3), wherein the thermosetting resin layer is formed of one or a plurality of materials selected from the group comprising polyamide-imide, polyesterimide, polyimide, class H polyester and polyetherimide.
(5) The rectangular insulated wire according to the aforementioned (1), wherein the thermosetting resin layer is formed on the rectangular conductor by bake-on coating.
(6) The rectangular insulated wire according to the aforementioned statement
(1), wherein the plurality of thermoplastic resin layers comprises a first thermoplastic resin layer and a second thermoplastic resin layer provided on the first thermoplastic resin layer.
(7) The rectangular insulated wire according to the aforementioned statement (6), wherein the first thermoplastic resin layer is formed on the thermosetting resin layer by extrusion, and further, the second thermoplastic resin layer is formed on the first thermoplastic resin layer by extrusion.
(8) The rectangular insulated wire according to any one of the aforementioned statements (1) to (4), wherein the rectangular conductor is one of aluminum or aluminum alloy and copper or copper alloy.
(9) An electric generator coil formed by winding the rectangular insulated wire as claimed in any one of the aforementioned statements (1) to (8).

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