| 摘要 |
A method and aqueous coating composition for forming an anti-stick and insulative coating on cold-rolled, non-oriented, semi-processed steel; cold-rolled, non-oriented, fully-processed steel; cold-rolled motor lamination steel; and punching quality oriented electrical steel. The coating composition has an inorganic portion and an organic portion. The inorganic portion comprises, on a water-free basis and by weight, 3% to 11% Al+++, 3% to 15% Mg++ and 78% to 87% H2PO4- calculated as Al2O3, MgO and H3PO4, respectively, the total weight percentage being 100% on a water-free basis and the concentration being 100 parts by weight on a water-free basis; and either 33 to 250 parts by weight colloidal silica on a water-free basis, together with from 10 to 25 parts by weight chromic anhydride for every 100 parts by weight H2PO4- calculated as H3PO4, or from 30 to 250 parts by weight aluminum silicate calculated as Al2O3.SiO2 on a water-free basis. The inorganic portion contains by weight at least 60% water when colloidal silica is used and at least 40% water when aluminum silicate is used. The organic portion comprises a water soluble or dispersible resin containing by weight at least 40% water. The inorganic and organic portions are combined so that the organic content is from about 15 to about 1350 parts by weight per 100 parts Al2O3, MgO and H3PO4 on a water-free basis. The coating composition is applied to the steel and cured at a strip temperature of from about 250 DEG F. (120 DEG C.) to about 750 DEG F. (400 DEG C.) in air.
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