High punchability heat resistant coating for sheet metal

摘要

Sheet steel used for making the cores of electrical machines is improved as to its punchability by coating it with a heat resistant coating of a complex mixture of phosphates and resins compatible with acid phosphate ions. The coating contains between 60 and 95% by weight of the phosphates and between 5 and 40% by weight of the resins. The resins can be acrylic base resins, ethylene-vinyl acetate copolymer resins, or thermosetting epoxy resins.