Mixtures for coating metallic surfaces

Abstract

A method for coating a metallic surface by contacting it with an aqueous copolymer dispersion, wherein the aqueous copolymer dispersion comprises an effective amount of magnesium ions and phosphate or phosphonate ions, the copolymers present in the dispersion being constructed from the following components: (A) from 20 to 95 weight % of monoethylenically unsaturated hydrocarbons and/or hydrocarbons having two conjugated double bonds, (B) from 5 to 80 weight % of monoethylenically unsaturated monomers which contain acid groups, and/or anhydrides or salts thereof. Further provided are metallic surfaces coated with such copolymers, and the use of such aqueous copolymer dispersions to coat metallic surfaces.

1 . A method for coating a metallic surface, the method comprising:
 bringing the metallic surface into contact with an aqueous copolymer dispersion, wherein the aqueous copolymer dispersion comprises an aqueous copolymer, a magnesium ion and a phosphate or phosphonate ion,   wherein the aqueous copolymer comprises:   (A) from 20 to 95 weight % of a monoethylenically unsaturated hydrocarbon and/or a hydrocarbon having two conjugated double bonds,   (B) from 5 to 80 weight % of a monoethylenically unsaturated monomer comprising an acid group, and/or an anhydride or a salt thereof.   
     
     
         2 . The method according to  claim 1 , wherein the aqueous copolymer further comprises:
 (C) from 0 to 30 weight % of an ethylenically unsaturated monomer different from components (A) and (B).   
     
     
         3 . The method according to  claim 1 , wherein a total amount of the magnesium ion, a phosphate ion, and a phosphonate ion is from 0.1 to 5 weight %, based on an amount of the aqueous copolymer. 
     
     
         4 . The method according to  claim 1 , wherein component (A) is at least one alkene selected from the group consisting of ethene, propene, 1-butene, 2-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. 
     
     
         5 . The method according to  claim 1 , wherein the acid group is at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, and a phosphonic acid group. 
     
     
         6 . The method according to  claim 1 , wherein 0.5 to 50 mol % of an acid group in the aqueous copolymer is neutralized. 
     
     
         7 . The method according to  claim 1 , further comprising:
 applying the aqueous copolymer by spraying, injecting, dipping, spread-coating or electrophoretic painting.   
     
     
         8 . The method according to  claim 1 , wherein a metal in the metallic surface is one selected from the group consisting of Mg, Al, steel, Zn, and a steel coated with Zn, Al, Ni, Sn, Cr, or an alloy thereof. 
     
     
         9 . The method according to  claim 1 , further comprising:
 contacting the aqueous copolymer dispersion with an intermediate coat,   wherein the intermediate coat is in contact with the metallic surface.   
     
     
         10 . The method according to  claim 9 , wherein the intermediate coat is a Cr conversion coat. 
     
     
         11 . The method according to  claim 1 , wherein the aqueous copolymer dispersion further comprises a film-former, a crosslinking component, a wetting agent, or a corrosion inhibitor different from the aqueous copolymer. 
     
     
         12 . A copolymer-coated metallic surface obtainable by the method according to  claim 1 . 
     
     
         13 . The coated metallic surface according to  claim 12 , comprising:
 one or more paint coats applied one over another located on a copolymer-containing coat.   
     
     
         14 . An aqueous copolymer dispersion comprising:
 an aqueous copolymer, a magnesium ion and a phosphate or phosphonate ion,   wherein the aqueous copolymer comprises:   (A) from 20 to 95 weight % of a monoethylenically unsaturated hydrocarbon and/or a hydrocarbon having two conjugated double bonds,   (B) from 5 to 80 weight % of a monoethylenically unsaturated monomer comprising an acid group, and/or an anhydride or a salt thereof.   
     
     
         15 . The aqueous copolymer dispersion according to  claim 13 ,
 wherein the aqueous copolymer dispersion is brought into contact with an intermediate coat, and   the intermediate coat is in contact with the metallic surface.