Surface treatment agent, surface-treated metal, and surface treatment method

Abstract

The surface treatment agent is designed to improve adhesion to a coating film. This agent contains at least one metal component (A) selected from the group consisting of zirconium, titanium, and hafnium, as well as an alkyldiallylamine polymer (C). The metal component (A) has a content ranging from 10 ppm to 10,000 ppm by mass, in terms of metal element, relative to the total mass of the surface treatment agent. Furthermore, the alkyldiallylamine polymer (C) includes a segment with a heterocyclic structure represented by formula (1a) or (1b).

What is claimed is: 
     
         1 . A surface treatment agent comprising:
 at least one metal component (A) selected from the group consisting of zirconium, titanium, and hafnium; and an alkyldiallylamine polymer (C),   wherein the metal component (A) has a content of 10 to 10000 ppm by mass in terms of metal element with respect to a total mass of the surface treatment agent, and   wherein the alkyldiallylamine polymer (C) comprises at least one of a segment having a heterocyclic structure represented by the following formula (1a) or a segment having a heterocyclic structure represented by the following formula (1b):   
       
         
           
           
               
               
           
         
         wherein R 1  in the above formulas (1a) and (1b) represents an alkyl group or an aralkyl group. 
       
     
     
         2 . The surface treatment agent according to  claim 1 , wherein the alkyldiallylamine polymer (C) has a weight average molecular weight of 500 to 500,000 and a content of 25 to 5,000 ppm by mass in terms of resin solid content concentration with respect to the total mass of the surface treatment agent. 
     
     
         3 . The surface treatment agent according to  claim 1 , further comprising at least one metal component selected from the group consisting of aluminum, copper, and zinc. 
     
     
         4 . The surface treatment agent according to  claim 1 , wherein the surface treatment agent has a pH of 2.0 to 6.0. 
     
     
         5 . The surface treatment agent according to  claim 1 , wherein the alkyldiallylamine polymer (C) has a content ratio of a sum of the segment having a heterocyclic structure represented by the above formula (1a) and the segment having a heterocyclic structure represented by the above formula (1b) of 25 mol % or more and 100 mol % or less with respect to all segments comprised in the alkyldiallylamine polymer (C). 
     
     
         6 . The surface treatment agent according to  claim 1 , wherein the surface treatment agent further comprises fluorine (B), and the fluorine (B) has a concentration of 10 to 12,500 ppm by mass in terms of fluorine element with respect to the total mass of the surface treatment agent. 
     
     
         7 . A surface-treated metal having a surface on which a surface treatment film is formed by the surface treatment agent according to  claim 1 . 
     
     
         8 . The surface-treated metal according to  claim 7 , wherein the surface treatment film has a content of the metal component (A) of 5 to 500 mg/m 2  in terms of metal element. 
     
     
         9 . A surface treatment method comprising forming a surface treatment film by treating a surface of an object to be coated with the surface treatment agent according to  claim 1 . 
     
     
         10 . The surface treatment method according to  claim 9 , further comprising forming an electrodeposited coating film by subjecting the object to be coated having the surface treatment film formed thereon to electrodeposition coating.