ELECTROMAGNETIC STEEL SHEET HAVING INSULATING COATING FILM WITH EXCELLENT THERMAL CONDUCTIVITY THEREIN, AND PROCESS FOR PRODUCTION THEREOF

摘要

An electromagnetic steel sheet comprises an electromagnetic steel sheet and an insulating coating film formed on the surface of the electromagnetic steel sheet. The insulating coating film is mainly composed of: a chromic acid metal salt; and a mixture or a copolymer of one or more members selected from a styrene resin, an acrylic resin, an epoxy resin and a polyimide resin, which has a rate of crystallization of 10 to 50% and is contained in an amount of 0.01 to 0.5 part by weight relative to 1 part by weight of the chromic acid metal salt (in terms of the CrO3 content). In the insulating coating film, a chromium hydroxide compound is contained as a chromic acid compound in an amount of 30% or more in terms of the chromium (III) oxide (Cr2O3) content relative to the total amount (100%) of the chromic acid compound in terms of the chromium (III) oxide (Cr2O3) content.