Surface treatment agent, method for forming surface treatment coating, and aluminum material or aluminum alloy material having surface treatment coating thereon/over

Abstract

To provide a non-chromate surface treatment agent that, without using one or two or more iron group compounds selected from oxides, hydroxides, or oxyhydroxides of iron, nickel, or cobalt, or the like, allows a surface treatment coating having excellent adhesion to an aluminum material or the like and an upper layer film and providing excellent corrosion resistance to the aluminum material or the like to be formed between the aluminum material or the like and the upper layer film, a method for forming a surface treatment coating using the surface treatment agent, and an aluminum material or an aluminum alloy material having thereon the surface treatment coating. The above challenge can be solved by a surface treatment agent that contains a water-soluble or water-dispersible organic polymer (A) containing a carbonyl group and/or hydroxyl group in a unit structure and an organic polymer (B) containing a phosphonic group.

1 . A surface treatment agent for treating a surface of an aluminum material or an aluminum alloy material, comprising:
 a water-soluble or water-dispersible organic polymer (A) having a carbonyl group and/or a hydroxyl group in a unit structure;   an organic polymer (B) having a phosphonic group; and optionally a metal compound (C), wherein   if the surface treatment agent comprises the metal compound (C), a ratio of the mass of metal (M M ) in the metal compound (C) to the mass of phosphorus (M P ) in the organic polymer (B), M M /M P , is 0.30 or less, and   the surface treatment agent does not comprise any of iron, nickel, cobalt, hexavalent chromium, compounds including metals thereof, and an amine compound having three or more hydroxyl groups in one molecule.   
     
     
         2 . The surface treatment agent according to  claim 1 , wherein the organic polymer (A) has a carboxyl group or a carboxylate ester group in a unit structure. 
     
     
         3 . The surface treatment agent according to  claim 1 , wherein the organic polymer (B) has three or more carbon atoms and two or more phosphonic groups in one molecule. 
     
     
         4 . The surface treatment agent according to  claim 1 , wherein the metal compound (C) has one or more transition metals. 
     
     
         5 . The surface treatment agent according to  claim 1 , wherein the metal compound (C) has one or more transition metals selected from titanium, tungsten, manganese, zirconium, and cerium. 
     
     
         6 . The surface treatment agent according to  claim 1 , wherein a weight average molecular weight of the organic polymer (A) is 2,000 or more and 1,000,000 or less. 
     
     
         7 . A method for forming a surface treatment coating, comprising a step of bringing the surface treatment agent according to  claim 1  into contact with a surface of an aluminum material or an aluminum alloy material. 
     
     
         8 . An aluminum material or an aluminum alloy material having thereon/over a surface treatment coating obtained using a method comprising a step of bringing the surface treatment agent according to  claim 1  into contact with a surface of an aluminum material or an aluminum alloy material. 
     
     
         9 . An aluminum material or an aluminum alloy material having a surface treatment coating thereon/over, wherein
 the surface treatment coating comprises:
 a water-soluble or water-dispersible organic polymer (A) having a carbonyl group and/or a hydroxyl group in a unit structure; 
 an organic polymer (B) having a phosphonic group; and 
 optionally a metal compound (C), 
   if the surface treatment coating comprises the metal compound (C), a ratio of the mass of metal (M M ) in the metal compound (C) to the mass of phosphorus (M P ) in the organic polymer (B), M M /MP, is 0.30 or less, and   the surface treatment coating does not comprise any of iron, nickel, cobalt, hexavalent chromium, compounds including metals thereof, and an amine compound having three or more hydroxyl groups in one molecule.