SILICON STEEL SHEET WITH INSULATING COATING PRODUCIBLE BY LOW TEMPERATURE BAKING, CAPABLE OF STRESS RELIEVING ANNEALING AND GOOD IN BOILING WATER VAPOR RESISTANCE AND SOLVENT RESISTANCE

摘要

PROBLEM TO BE SOLVED: To obtain a silicon steel with insulating coating producible by low temp. baking, capable of stress relieving annealing and good in boiling water vapor resistance and solvent resistance by blending resin whose glass transition point lines in a specified range with alumina. ;SOLUTION: Water base resin having 30 to 150°C glass transition point is blended into a treating soln. Furthermore, for enabling stress relieving annealing without deteriorating its boiling water vapor resistance, alumina is blended by 3 to 300 pts.wt. expressed in terms of Al₂O₃ to 100 pts.wt. resin solid content. As a stabilizer for alumina, preferably, organic acid such as carboxylic acid of formic acid, active acid, propionic acid or the like are used. This coating soln. is applied to the surface of a silicon steel sheet, which is baled at 50 to 250°C arrival sheet temp. To obtain the silicon steel sheet with insulated coating in which the coating weight of the insulated coating is regulated to 0.05 to 4g/m². In the case the glass transition point of the resin is less than 30°C, its boiling water vapor resistance and solvent resistance and made poor, and in the case of 150°C, coating formability at the time of the low temp. baking deteriorates.;COPYRIGHT: (C)1998,JPO