To increase bonding strength, anticorrosion and blocking resistance, by spreading water-based paint where hardening agent is compounded with water-dispersed type resin at a specified ratio, on at least a single side of an electromagnetic steel plate in such a manner that a specified dry film thickness is obtained, and baking the water-based paint at a specified temperature.
Water-dispersed type resin which is grafting material of polymeric epoxy resin and polymeric acrylic based resin is used as base resin. Regarding the grafting material of the polymeric epoxy resin (A) and the polymeric acrylic based resin (B), solid content weight % of (A)/(B) is set to be 55/45-95/5. Number-average molecular weight of the polymeric epoxy resin (A) is set to be 1200-8000. The loadings of hardening agent in water-based paint, as a ratio of the solid content, is set to be 1-40 pts.wt. to the water-dispersed type resin 100 pts.wt. The water-based paint is spread on an electromagnetic steel plate and baked, and a covering film for lamination bonding is formed. The film thickness of the covering film is set to be 1.0-12 μm as dry film thickness, and the baking temperature is set to be 100-300°C as reaching plate temperature.
KUBOTA TAKAHIRO
SAGIYAMA MASARU
IMAZAKI YOSHIO
EZAKI SUMIO
KANSAI PAINT CO LTD