Zr, mo and acid-functional polymer containing aqueous compositions for treatment of metallic surfaces

Abstract

Disclosed herein are a method for treatment of at least one metallic surface of a substrate including at least a step of contacting said surface with an acidic aqueous composition (A), said acidic aqueous composition (A) including Zr ions (a) at least one polymer (P) selected from the group consisting of poly(meth)acrylic acids and (meth)acrylic copolymers, as constituent (b), and Mo ions (c), where the relative weight ratio of Zr ions (a) to Mo ions (c), in each case calculated as metal, is in a range of from 40:1 to 7.5:1, to a corresponding acidic aqueous composition (A) as such,a method of using the acidic aqueous composition (A) for treating metallic surfaces and substrates including the thus treated surfaces.

1 . A method for treatment of at least one surface of a substrate, wherein said surface is at least partially made of at least one metal, comprising 
 (1) contacting the at least one surface of the substrate with an acidic aqueous composition (A), 
 wherein the acidic aqueous composition (A) has a pH value in a range of from 2.5 to <5.0 and comprises 
 (a) zirconium ions in an amount in a range of from 10 to 200 ppm, calculated as metal, 
 (b) at least one polymer (P), wherein the polymer (P) is selected from the group consisting of poly(meth)acrylic acids and (meth)acrylic copolymers, which bear carboxylic acid groups, and mixtures thereof, and 
 (c) molybdenum ions in an amount in a range of from 0.5 to 10 ppm, calculated as metal, 
 wherein the relative weight ratio of zirconium ions (a) to molybdenum ions (c), in each case calculated as metal, is in a range of from 40:1 to 7.5:1. 
 
   
     
     
         2 . The method according to  claim 1 , wherein the relative weight ratio of zirconium ions (a) to molybdenum ions (c), in each case calculated as metal, is in a range of from 35:1 to 8:1. 
     
     
         3 . The method according to  claim 1 , wherein the acidic aqueous composition (A) comprises 
 zirconium ions in an amount in a range of from 15 to 150 ppm, in each case calculated as metal, and/or,   molybdenum ions in an amount in a range of from 1 to 8 ppm in each case calculated as metal.   
     
     
         4 . The method according to  claim 1 , wherein the acidic aqueous composition (A) has a pH value in a range of from 2.6 to 4.8. 
     
     
         5 . The method according to  claim 1 , wherein the acidic aqueous composition (A) has a temperature in a range of from 18 to 35° C. 
     
     
         6 . The method according to  claim 1 , wherein the at least one polymer (P) has a weight average molecular weight (M w ) in a range of from 40000 to 350000 g/mol. 
     
     
         7 . The method according to  claim 1 , wherein polymer (P) is a poly(meth)acrylic acid . 
     
     
         8 . The method according to  claim 1 , wherein polymer (P) is present in composition (A) in an amount in the range of from 50 to 2000 ppm. 
     
     
         9 . The method according to  claim 1 , wherein the zirconium ions (a) are incorporated into composition (A) in form of their complex fluorides. 
     
     
         10 . The method according to  claim 1 , wherein the molybdenum ions (c) are incorporated into composition (A) in form of at least one molybdate . 
     
     
         11 . The method according to  claim 1 , wherein the acidic aqueous composition (A) contains free fluoride ions in an amount in the range of from 1 to 500 ppm. 
     
     
         12 . The method according to  claim 1 , wherein polymer (P) does not contain any phosphonic acid and/or phosphonate groups. 
     
     
         13 . An acidic aqueous composition (A), wherein the acidic aqueous composition (A) has a pH value in a range of from 2.5 to <5.0 and comprises 
 (a) zirconium ions in an amount in a range of from 10 to 200 ppm, calculated as metal,   (b) at least one polymer (P), wherein the polymer (P) is selected from the group consisting of poly(meth)acrylic acids and (meth)acrylic copolymers, which bear carboxylic acid groups, and mixtures thereof, and   (c) molybdenum ions in an amount in a range of from 0.5 to 10 ppm, calculated as metal,   wherein the relative weight ratio of zirconium ions (a) to molybdenum ions (c), in each case calculated as metal, is in a range of from 40:1 to 7.5:1.   
     
     
         14 . A method of using the acidic aqueous composition (A) of  claim 13 , the method comprising using the acidic aqueous composition(A) for treating at least one surface of a substrate, wherein said surface is at least partially made of at least one metal. 
     
     
         15 . A substrate comprising at least one surface, wherein said surface is at least partially made of at least one metal, wherein said at least one surface has been treated according to the method of  claim 1 . 
     
     
         16 . The method according to  claim 1 , wherein the relative weight ratio of zirconium ions (a) to molybdenum ions (c), in each case calculated as metal, is in a range of from 12:5 to 10:1. 
     
     
         17 . The method according to  claim 1 , wherein the acidic aqueous composition (A) comprises
 zirconium ions in an amount in a range of from 20 to 35 ppm, in each case calculated as metal, and,   molybdenum ions in an amount in a range of from >2 to 3 ppm, in each case calculated as metal.   
     
     
         18 . The method according to  claim 1 , wherein the acidic aqueous composition (A) has a pH value in a range of from 3.2 to 3.8. 
     
     
         19 . The method according to  claim 1 , wherein the acidic aqueous composition (A) has a temperature in a range of from 20 to 30° C. 
     
     
         20 . A substrate comprising at least one surface, wherein said surface is at least partially made of at least one metal, wherein said at least one surface has been treated by the acidic composition (A) according to  claim 13 .