| 摘要 |
1,185,706. Coatings. YAWATA IRON & STEEL CO. Ltd. 14 March, 1967 [18 March, 1966], No. 11814/67. Heading B2K. [Also in Divisions C7 and H1] An electrically insulating coating is formed on an electric steel sheet by applying an aqueous composition containing a phosphorus compound and a lignin derivative and heating at 20-500‹C for 1-120 seconds. Sulphurous, nitric or hydrochloric acid derivatives of lignin, or lignin sulphonates of ammonium, alkali alkaline earth, Group IB or Group IIB metals may be used in an amount 1-90% by wt of the composition. The phosphorous compound may be ortho-, pyro- or polyphosphoric acid, phosphorous or hypophosphorous acid, or an orthophosphate, preferably in an amount 0.5- 15% by wt. The composition may also contain chromic acid, or a water-soluble chromium compound, or boric acid or a watersoluble boron compound. Optional additives also include an alcohol, polyalcohol or formalin solvent; ethylene or polyethylene glycol, glycerine, polyvinyl alcohol, methyl ethyl cellulose, starch, polyacrylic acid or an amino resin in a ratio .1-1:1 by wt. of the lignin compound, to improve adhesion; oxides of Mg, Ti, V, Mo, Mn, Fe, Ni, Cu, Zn, Al, Pb, Sb, Si, or mica, talc or bentonite to increase heat and electrical resistance; and a polyethylene glycol lauryl ether as surfactant. The pH may be controlled by addition of CH 3 COOH, HC1, HNO 3 , HN0 2 , H 2 SO 4 , HC10, HClO 4 , or NH 3 or an alkali or alkaline earth metal compound. The organic components should constitute at least 30% by wt. of the dried coating. Compositions exemplified are as follows:-(1) (Comparative) Ca lignin sulphonate, H 2 O; (2) Ca lignin sulphonate, H 3 PO 4 , H 2 O; (3) lignin sulphonic acid, H 3 PO 4 , CrO 3 , H 2 O; (4) NH 4 lignin sulphonate, Zn(H 2 PO 4 ) 2 , polyvinyl alcohol, H 2 O; (5) Ca lignin sulphonate, H 3 PO 4 , polyvinyl alcohol, polyethylene glycol lauryl ether, H 2 O. The composition may be applied in an amount 0.5-10 g/m<SP>2</SP> (dried weight) by rolling or spraying. |
