Coating composition for electrical steel sheet, electrical steel sheet, laminated core, and rotary electric machine

Patent metadata

Field	Value
Publication number	US-12344759-B2
Application number	US-202118010264-A
Country	US
Kind code	B2
Filing date	Jun 17, 2021
Priority date	Jun 17, 2020
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

An electrical steel sheet used for a laminated core is an electrical steel sheet including an insulation coating 3 on a surface of a base steel sheet 2 , the insulation coating being coated with a coating composition for an electrical steel sheet. The coating composition for an electrical steel sheet includes: an epoxy resin; an epoxy resin curing agent; and an elastomer-modified phenolic resin, in which the amount of the elastomer-modified phenolic resin is 10 parts by mass to 100 parts by mass with respect to 100 parts by mass of the epoxy resin.

First claim

What is claimed is:

1. A coating composition for an electrical steel sheet comprising:
an epoxy resin;
an epoxy resin curing agent; and
an elastomer-modified phenolic resin,
wherein an amount of the elastomer-modified phenolic resin is 10 parts by mass to 100 parts by mass with respect to 100 parts by mass of the epoxy resin,
wherein a weight average molecular weight of an elastomer portion of the elastomer-modified phenolic resin is 4,000 to 200,000,
wherein when the coating composition is applied to a surface of the electrical steel sheet and cured at a reaching temperature during baking of 120 to 200° C. and baking time of 5 to 40 seconds, a curing shrinkage rate measured by changing a coating thickness according to JIS K 6941 is 15% or less.

2. The coating composition for an electrical steel sheet according to claim 1 ,
wherein the curing shrinkage rate measured by changing a coating thickness according to JIS K 6941 is 10% or less.

3. An electrical steel sheet comprising:
an insulation coating containing the coating composition for an electrical steel sheet according to claim 2 on a surface of the electrical steel sheet, wherein the insulation coating is in a cured state, an uncured state, or a semi-cured state.

4. An electrical steel sheet comprising:
an insulation coating containing the coating composition for an electrical steel sheet according to claim 1 on a surface of the electrical steel sheet, wherein the insulation coating is in a cured state, an uncured state, or a semi-cured state.

5. A laminated core,
wherein a plurality of the electrical steel sheets according to claim 4 are laminated and caused to adhere together, and
wherein the insulation coating is in a cured state.

6. A rotary electric machine comprising:
the laminated core according to claim 5 .

Assignees

• Nippon Steel Corp

Inventors

• Takeda Kazutoshi
• TAKATANI Shinsuke
• Fukuchi Minako
• Tanaka Ichiro

Classifications

• B32B15/04

  comprising metal as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a bituminous or tarry layer B32B11/08; next to a water-setting substance layer B32B13/06; next to a glass layer B32B17/061; next to a cellulosic plastic layer B32B23/042)} · CPC title

• B32B15/08

  of synthetic resin · CPC title

• B32B15/043

  of metal (B32B15/01 takes precedence) · CPC title

• Y10T428/12965

  Both containing 0.01-1.7% carbon [i.e., steel] · CPC title

• Y10T428/12569

  Synthetic resin · CPC title