Surface-treating agent for metallic material with excellent suitability for press forming and chemical treatment and method of treatment

Abstract

A metallic sheet for motor vehicles which is excellent press forming property and chemical layer generation property, and a process for producing the sheet. The treating chemicals apply to a metal surface consists of (A) particles of phosphate of metal selected from Zn, Fe, Mn, Ni, Co, Ca, Mg and Al, the average size of the particles are 3 μm or smaller, (B) a dispersing agent, and water. It is applied to a metal surface and then dried. Dispersing agent (B) include orthophosphoric acid, polyphosphoric acid, and organic phosphonic acid compounds. (B) also include polymer formed from a monomer represented by the chemical formula(1). Further more, monosaccharides, polysaccharaides or derivatives of vinylacetate may also be used as (B). It is applied to the metal surface so as to form a film in an amount of 0.05 to 3 g/m 2 on a dried basis.

1 . Treating chemicals apply to a metal surface for giving excellent properties in press forming and in chemical layer generation containing as main constituent (A): one or more than one phosphate particles of 2 valence or 3 valence metal being selected from Zn, Fe, Mn, Ni, Co, Ca, Mg and Al and having mean particle size of 3 μm or less, (B): dispersing agent for dispersing above phosphate particles, and water.  
     
     
         2 . Treating chemicals according to  claim 1  wherein dispersing agent (B) is one or more than one compound being selected from orthophosphoric acid, polyphosphoric acid and organic phosphonic acid.  
     
     
         3 . Treating chemicals according to  claim 1  wherein dispersing agent (B) is one or more than one polymer or copolymer obtainable by polymerize one or more than one monomer being selected from monomer of chemical formula (1) (wherein R 1  is H or CH 3 , R 2  is H or alkyl group of 1˜5 C or hydroxyalkyl group of 1˜5 C) and α, β unsaturated carboxylic acid monomer with less than 50 wt % of monomer being able to copolymerize with the afore said monomer.  
       
         
           
           
               
               
           
         
       
     
     
         4 . Treating chemicals according to  claim 1  wherein dispersing agent (B) is one or more than one compound being selected from monosaccharide, polysaccharide and their derivative.  
     
     
         5 . Treating chemicals according to  claim 1  wherein dispersing agent (B) is one or more than one water soluble polymer compound comprising polymer of vinylacetate or its derivative or copolymer between vinylacetate and monomer being able to copolymerize with the vinylacetate.  
     
     
         6 . Treating process of a metal surface for giving excellent press forming property and chemical layer generating property wherein any of the treating chemical in  claim 1  ˜5 is applied to the metal surface and dry, and form a film of 0.05˜3 g/m 2  on the metal surface.