Patent ID: 6369149
Filing Date: 2002-04-09
Classification: C09D,C23C

Abstract:
An aqueous surface treatment composition for aluminiferous surfaces, said composition having a pH from 2.5 to 4.5 and comprising water and the following concentrations of the following components:(A) at least 0.1 g/L of orthophosphate ions; (B) from 0.1 to 3 g/L of condensed phosphate ions; (C) from 0.1 to 0.5 g/L of free hydrofluoric acid; and (D) at least 0.1 g/L of water-soluble polymer molecules that, except for end groups as generally known in the art, conform to general formula (I) below: in which n is the degree of polymerization and has an integral value or each molecule, the average value of n for all of the molecules present being from 2 to 50 and not necessarily integral, X in each structural unit is independently selected from the hydrogen atom and a moiety Y conforming to general formula (II): wherein each of R1 and R2 is selected, independently of each other and independently from one Y moiety to another, except as noted below, from the group of moieties consisting of alkyl moieties and hydroxy alkyl moieties having from 1 to 3 carbon atoms each, all with the proviso that the polymer molecules must contain moieties Y in a sufficient amount that the molar ratio of Y to the total of aromatic rings is from 0.2:1.0 to 1.0:1.0.