| 摘要 |
A surface of aluminiferous metal is brought into contact at 30 ~C to 65 ~C for 5 to 60 seconds with a surface treatment bath with a pH of 2.0 to 6.5 that contains phosphate ion, condensed phosphate ion, and a water soluble polymer in the following weight proportions: 1 - 30 : 0.1 - 10 : 0.2 - 20. This is followed by a water rinse and drying by heating. The water soluble polymer has a chemical structure conforming with formula (I), in which (i) each of X1 and X2 represents a hydrogen atom, a C1 to C5 alkyl group, or a C1 to C5 hydroxyalkyl group; (ii) each of Y1 and Y2 represents a hydrogen atom or a moiety "Z" that conforms to formula (II) or (III), wherein each of R1, R2, R3, R4, and R5 represents a C1 to C10 alkyl group or a C1 to C10 hydroxyalkyl group; (iii) the average value for the number of Z moieties substituted on each phenyl ring in the polymer molecule is from 0.2 to 1.0; (iv) n is an integer with a value from 2 to 50; and (v) each polymer molecule contains at least one Z moiety.
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