Filiform corrosion-resistant primer coating composition and method for preventing filiform corrosion

摘要

A filiform corrosion-resistant primer coating composition for use in application to a metallic substrate, comprising a film forming component containng a film-forming resinous material and a hydrotalcite component, characterized in that the hydrotalcite component is a hydrotalcite solid solution represented by the following formula (1)wherein M²⁺ represents at least one divalent metal cation elected from the group consisting of Zn, Cd, Pb, Ca and Sr, M³⁺ represents a trivalent metal cation, A^n- represents an anion having a valence of n, and x, y1, y2 and m represent positive numbers which satisfy the following conditions: 0x50.5, 0y1, 0y2, 0.5≦y1 + y21, and O≦m2, the amount of the hydrotalcite solid solution being 0.1 to 20 parts by weight per 100 parts by weight of the film-forming component.