COATING SOLUTION FOR FORMING INSULATING FILM, METHOD FOR FORMING INSULATING FILM OF NON-ORIENTED ELECTRICAL STEEL SHEET AND NON-ORIENTED ELECTRICAL STEEL SHEET BY USING IT

摘要

Disclosed is a coating composition having superior compatibility and surface gloss for forming an insulating film and a method of forming the film. The coating composition includes, based on 100 g of a mixture solution of monoaluminum phosphate and monozinc phosphate, 0.5-5 g of a mixture solution of cobalt hydroxide and strontium hydroxide, 150-300 g of a polyester emulsion resin, 3-10 g of aluminum silicate, and 0.5-6.0 g of a chelating agent, in which the polyester emulsion resin has a weight average molecular weight of 2,000-15,000, a solid content of 15-25% and a viscosity of 100-500 cp. Even when the coating composition which is chromium-free is applied in the form of a thick film on a non-oriented electrical steel sheet, superior insulating properties, corrosion resistance, film adhesion, compatibility and surface gloss can be exhibited.