| 摘要 |
<p>A composition comprising a solution in at least one organic solvent of: (A) 50 to 65 parts by weight of a composition consisting essentially of one part by weight of a polymeric polyol (i.e. a polymer containing several hydroxy groups), 0.05 to 5.0 parts of an epoxy aryl ether, and 0.1 to 2.0 parts of phosphoric acid; (B) 0.01 to 1.5 parts of a dilute aqueous solution of at least one inorganic, water-soluble chromium compound, at least a portion of the chromium in said solution being hexavalent chromium; and (C) 4-30 parts of a non-reactive inorganic filler. Preferred component A is a styrene-alkyl alcohol copolymer and the epoxy aryl ether prepared by the reaction of epihalohydrin with a phenolic compound, e.g. epichlorohydrin with bisphenol A. Preferred component B is a dilute aqueous solution containing (1) calcium dichromate and (2) partially reduced chromic acid. Preferred components C are silica, alumina, carbon black, titanium dioxide, magnesium silicate or a clay. Organic solvents employed in the examples are methyl isobutyl ketone, xylene, ethyl acetate, isobutyl alcohol, ethylene glycol monobutyl ether and high boiling aromatic solvent. In examples, component B is prepared by partially reducing chromic acid with methanol and water and adding calcium dichromate.ALSO:A metal article is provided with a protective film by applying to its surface a film comprising a composition comprising a solution in at least one organic solvent of (A) 50-65 parts by weight of a composition consisting essentially of one part by weight of a polymeric polyol (i.e. a polymer containing several hydroxy groups, 0.05-5.0 parts of an epoxy aryl ether, and 0.1-2.0 parts of phosphoric acid; (B) 0.01-1.5 parts of a dilute aqueous solution of at least one inorganic, water-soluble chromium compound, at least a portion of the chromium in said solution being hexavalent chromium; and (C) 4-30 parts of a non-reactive inorganic filler, and drying said film. The compositions may be applied by dip-coating, roller-coating or spraying &c. They are particularly suitable as primer coatings for steel surfaces, also aluminium, galvanized steel and similar metal surfaces. The primer-coated surface may then be further treated with a siccative organic coating composition e.g. an alkyd, epoxy or acrylic paint.</p> |
