An electroplated composite coating of the invention which comprises 70 to 99.9 percent by weigth of zinc or an alloy of zinc and 0.1 to 30 percent by weight of an organic polymer, said polymer being soluble in water and anionic, carionic or amphoteric, having been dispersed in the electroplated crystal grains or gain boundaries of the zinc and/or the zinc alloy, having a weight-average molecular weight of 1,000 to 1,000,000,
said polymer having at least one aromatic ring and 1 to 10 hydroxyl group on the average per a molecular weight unit of 500,
said polymer containing therein a polar group selected from the group consisting of: sulfo group,
a phosphoric acid group of the formula -O-PO(OR)2,
a phosphorous acid group of the formula -0-PO(OR)2,
a phosphonic acid group of the formula -PO(OR)2,
a phosphonous acid group of the formula -P(OR)2,
a phosphinic acid group of the formula -RPO(OR),
a phosphinous acid group of the formula -PR(OR),
a tertiary amino group of the formula -NR1 R2,
a quaternary ammonium group of the formula -NR1 R2R3.X and
carboxyl group having the formula -COOH,
in which R is hydrogen or a hydrocarbon group and R1, R2 and R3 each are a straight or branched alkyl, a straight or branched hydroxyalkyl, an aromatic ring and X is a counter anion,
the sulfo group being contained therein on the average in an amount of 0.1 to 4 groups per a molecular weight unit of 500, the other groups being contained therein on the average in a total amount of 0.1 to 5 groups per a molecular weight of 500,
the main chain briding between two aromatic rings being at least one of C-C linkage, C = C linkage and an ether linkage (C-O-C).
本发明的一种电镀复合涂层,由重量百分比为 70%至 99.9%的
锌或
锌合
金和重量百分比为 0.1%至 30%的有机聚合物组成,所述聚合物可溶于
水,具有阴离子、阳离子或两性离子特性,分散在
锌和/或
锌合
金的电镀晶粒或增殖边界中,其重量平均分子量为 1,000 至 1,000,000 、
所述聚合物具有至少一个芳香环和 1 至 10 个羟基,平均每个分子量单位为 500、
所述聚合物含有一个极性基团,该极性基团选自以下组别: 磺基、
式-O-PO(OR)2.的
磷酸基团
式-0-PO(OR)2 的
磷酸基团
式-PO(OR)2 的
膦酸基团
式-P(OR)2 的
亚磷酸基团
式-RPO(OR)2 的
膦酸基团
式-PR(OR)的
膦酸基
式-NR1 R2 的叔
氨基
式-NR1 R2R3.X 的季
铵基团和
式-COOH.X 的羧基、
其中 R 为氢或烃基,R1、R2 和 R3 分别为直链或支链烷基、直链或支链羟烷基、芳香环,X 为反阴离子、
磺基的平均含量为每 500 个分子量单位 0.1 至 4 个基团,其他基团的平均含量为每 500 个分子量单位 0.1 至 5 个基团、
两个芳香环之间的主链至少是 C-C 连接、C = C 连接和醚连接(C-O-C)中的一种。