Process for treatment of aluminum - or metal cans to increase the corrosion resistance and to reduce the coefficient of friction and composition of the treatment liquid.

摘要

A corrosion resistant film with a low coefficient of friction that facilitates automatic conveying can be formed on the surface of tin-plated steel or of aluminum, particularly DI cans of one of these types of metal, by contacting the aluminum or the tin plated steel with an aqueous liquid composition having a pH in the range from 2.0 to 6.5 and containing: (A) from 1 to 30 g/L of phosphate ions, (B) from 0.1 to 10 g/L of condensed phosphate ions, and (C) from 0.1 to 20 g/L as solids of a water-soluble resin component selected from the group of resins, including mixtures of resins, having general chemical formula (I) wherein n is an integer within the range from 10 to 80 inclusive; each of X and Y is independently selected from hydrogen or a group 'Z' with formula (II), except that at least 15 % the total of all of the X and Y groups in this component of the composition are Z rather than hydrogen; and (II) wherein each of R1 and R2 in each of the phenyl rings in the formula independently is selected from the group consisting of alkyl groups containing from 1 to 10 carbon atoms per group and hydroxyalkyl groups containing from 1 to 10 carbon atoms per group.