Aqueous metal surface treatment agent for lithium ion secondary battery

Abstract

This is to provide an aqueous metal surface treatment agent for a lithium ion secondary battery which can improve interlaminar adhesiveness between a metal member and a resin coating layer such as a film or a coated film, and solvent resistance without using trivalent chromium. The aqueous metal surface treatment agent for a lithium ion secondary battery comprises a polyvinyl alcohol resin containing 2 to 15 mol % of a 1,2-diol structural unit represented by the formula (1): having a degree of saponification of 90 to 99.9 mol % and an average degree of polymerization of 250 to 3000; and a metallic crosslinking agent.

1 . An aqueous metal surface treatment agent for a lithium ion secondary battery which comprises a polyvinyl alcohol resin containing 2 to 15 mol % of a 1,2-diol structural unit represented by the formula (1): 
       
         
           
           
               
               
           
         
       
       wherein R1, R2 and R3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a connecting chain, and R4, R5 and R6 each independently represent a hydrogen atom or an organic group, and having a degree of saponification of 90 to 99.9 mol % and an average degree of polymerization of 250 to 3000; and a metallic crosslinking agent. 
     
     
         2 . The metal surface treatment agent according to  claim 1 , wherein a molar ratio of the polyvinyl alcohol resin:the metallic crosslinking agent is 1:5 to 500:1. 
     
     
         3 . The metal surface treatment agent according to  claim 1 , wherein the metallic crosslinking agent is selected from the group consisting of an oxide, a hydroxide, a complex compound, an organometallic compound, an organic acid salt and an inorganic acid salt of titanium, aluminum, zirconium, vanadium, molybdenum, cerium, lanthanum or tungsten. 
     
     
         4 . The metal surface treatment agent according to  claim 2 , wherein the metallic crosslinking agent is selected from the group consisting of an oxide, a hydroxide, a complex compound, an organometallic compound, an organic acid salt and an inorganic acid salt of titanium, aluminum, zirconium, vanadium, molybdenum, cerium, lanthanum or tungsten.