Insulated flat conductive wire having high aspect ratio, method for manufacturing same, and coil

Patent metadata

Field	Value
Publication number	US-10706992-B2
Application number	US-201815937036-A
Country	US
Kind code	B2
Filing date	Mar 27, 2018
Priority date	Aug 22, 2017
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

This insulated flat conductive wire includes: a flat conductive wire having an aspect ratio a/b of 12 or more, wherein the aspect ratio is a ratio of a length a of a long side of a rectangular cross-section to a length b of a short side thereof; and an insulating film which consists of a polyamide-imide resin or a polyimide resin and coats the flat conductive wire, wherein the insulating film has a film thickness t1 of 10 μm or more at a center portion of the long side of the rectangular cross-section, and the insulating film has a film thickness ratio t1/t2 of 0.80 to 1.35, and wherein the film thickness ratio t1/t2 is a ratio of the film thickness t1 at the center portion of the long side to a film thickness t2 at an edge portion of the long side of the rectangular cross-section.

First claim

What is claimed is:

1. An insulated flat conductive wire having a high aspect ratio, comprising:
a flat conductive wire having an aspect ratio a/b of 12 or more, wherein the aspect ratio is a ratio of a length a of a long side of a rectangular cross-section to a length b of a short side thereof; and
an insulating film which consists of a polyamide-imide resin and coats the flat conductive wire, wherein
a cross-sectional area of the flat conductive wire is set so that a diameter of a round wire having the same cross-sectional area as the rectangular cross-section of the flat conductive wire becomes 0.5 mm to 4.5 mm,
the polyamide-imide resin has a number average molecular weight Mn of 2.0×10 4 to 4.0×10 4 when converted to standard polystyrene, and
the insulating film has a film thickness t1 of 10 μm or more at a center portion of the long side of the rectangular cross-section, and the insulating film has a film thickness ratio t1/t2 of 0.80 to 1.35, and wherein the film thickness ratio t1/t2 is a ratio of the film thickness t1 at the center portion of the long side to a film thickness t2 at an edge portion of the long side of the rectangular cross-section.

2. A coil comprising:
the insulated flat conductive wire having a high aspect ratio according to claim 1 which is coiled.

3. A method for manufacturing the insulated flat conductive wire having a high aspect ratio according to claim 1 , the method comprising:
an electrodeposition solution preparation step of mixing a polyamide-imide resin having a number average molecular weight Mn of 2.0×10 4 to 4.0×10 4 when converted to standard polystyrene, a polar organic solvent, and a base, stirring the mixture at a temperature of 20° C. to 25° C. for 3 hours or more to obtain a mixed solution, and subsequently adding water to the mixed solution to prepare an electrodeposition solution;
an electrodeposition step of immersing a flat conductive wire having an aspect ratio a/b of 12 or more in the electrodeposition solution, wherein the aspect ratio is a ratio of a length a of a long side of a rectangular cross-section to a length b of a short side thereof, and causing a direct current to flow at a voltage of 150 V or higher in the electrodeposition solution, thereby electrodepositing particles of the polyamide-imide resin on a surface of the flat conductive wire; and
a baking step of heating the flat conductive wire, on which the particles of the polyamide-imide resin have been electrodeposited, to form an insulating film on the surface of the flat conductive wire, wherein
a cross-sectional area of the flat conductive wire is set so that a diameter of a round wire having the same cross-sectional area as the rectangular cross-section of the flat conductive wire becomes 0.5 mm to 4.5 mm.

4. The method for manufacturing the insulated flat conductive wire according to claim 3 ,
wherein the baking step includes: a low-temperature heating step of heating the flat conductive wire, on which the particles of the polyamide-imide resin have been electrodeposited, at a low temperature of 150° C. to 220° C. for 0.25 to 30 minutes; and a high-temperature heating step of heating the flat conductive wire, which has been heated at the low temperature, at a high temperature that is 30° C. or more higher than the temperature in the low-temperature heating step for 0.25 to 30 minutes.

5. The insulated flat conductive wire according to claim 1 , wherein the film thickness ratio t1/t2 is in a range of 0.98 to 1.30.

6. The insulated flat conductive wire according to claim 1 , wherein the film thickness at the center portion is 100 μm or less.

7. The insulated flat conductive wire according to claim 1 , wherein the insulating film is formed by an electrodeposition method.

8. The insulated flat conductive wire according to claim 1 , wherein the film thickness t1 is an average value of two locations at an upper side and a lower side in a center of the long side of the rectangular cross-section.

9. The insulated flat conductive wire according to claim 1 , wherein the film thickness t2 is an average value of four locations at upper sides and lower sides in both edges of the long side of the rectangular cross-section.

10. The insulated flat conductive wire according to claim 1 , wherein the edge portion of the long side of the rectangular cross-section is an end portion of the rectangular cross-section where roundness of the insulating film disappears, and the long side of the flat conductive wire and a surface of the insulating film begin to be parallel to each other.

Assignees

• Mitsubishi Materials Corp

Inventors

• Sakurai Hideaki
• Hirano Koji

Classifications

• C09D5/4461

  Polyamides; Polyimides · CPC title

• C25D13/06

  with polymers {(not used, see C09D5/44)} · CPC title

• H01B7/02 Primary

  Disposition of insulation · CPC title

• H01B7/08

  Flat or ribbon cables · CPC title

• H01B13/06

  Insulating conductors or cables (H01B13/32 takes precedence) · CPC title