Non-chrome passivation of steel

Abstract

Chromate free treatments and compositions for applying a conversion or passivation coating to metal surfaces. Preferred compositions comprise a film forming latex polymer, fluoacid, phosphoric acid, and a polyoxyethylene/oxypropylene block copolymer. The requisite metal surfaces are contacted by the compositions and dried. Rinsing is optional.

1 . A method of forming a conversion or passivation coating on a metal surface comprising contacting said metal surface with an aqueous treatment composition comprising: 
 (a) a film forming latex polymer;    (b) a fluoacid;    (c) phosphoric acid; and    (d) a non-ionic polymeric surfactant.    
   
   
       2 . A method as recited in  claim 1  wherein said non-ionic polymeric surfactant comprises a polyoxyethylene/oxypropylene block copolymer.  
   
   
       3 . A method as recited in  claim 2  wherein said latex polymer comprises an acrylate resin.  
   
   
       4 . A method as recited in  claim 3  wherein acid acrylate resin comprises butyl acrylate, methyl methacrylate, and methacrylic acid polymers.  
   
   
       5 . A method as recited in  claim 2  wherein said fluoacid comprises a fluoacid of a Group IVB metal.  
   
   
       6 . A method as recited in  claim 2  wherein said polyoxyethylene/polypropylene block copolymer comprises a mole ratio of ethylene oxide (EO):propylene oxide (PO) groups of about 1:1-9.  
   
   
       7 . A method as recited in  claim 6  wherein said EO:PO molar ratio is about 1:5-9.  
   
   
       8 . A method as recited in  claim 7  wherein said polyoxyethylene/polypropylene block copolymer has a molecular weight of about 2,000-4,000.  
   
   
       9 . A method as recited in  claim 2  wherein said metal surface is a zinc covered metal surface.  
   
   
       10 . A method as recited in  claim 2  wherein said metal surface is galvanized steel.  
   
   
       11 . A method as recited in  claim 2  wherein said metal surface is aluminum.  
   
   
       12 . A method as recited in  claim 2  wherein said treatment composition is chromate free.  
   
   
       13 . A method as recited in  claim 2  further comprising drying said metal after said coating has been brought into contact with said metal, then painting said metal.  
   
   
       14 . Composition for treating metal surfaces to form a conversion or passivation coating thereon, said composition comprising (a) a film forming latex polymer; (b) a fluoacid of a Group IVB metal; (c) phosphoric acid; and (d) a non-ionic polymeric surfactant, and water.  
   
   
       15 . Composition for treating metal surfaces to form a conversion or passivation coating thereon, said composition comprising: 
 0.01-50 wt % of a film forming latex polymer;    0.01-40 wt % H 3 PO 4 ;    0.01-30 wt % fluoacid;    0.01-20 wt % polyoxyethylene/oxypropylene block copolymer;    remainder water, wherein said composition equals 100 wt %.    
   
   
       16 . Composition as recited in  claim 15  wherein said composition is devoid of chromate, said polyoxyethylene/oxypropylene block copolymer comprising a mole ratio of ethylene oxide (EO):propylene oxide (PO) groups of about 1:1-9.  
   
   
       17 . Composition as recited in  claim 16  wherein said EO:PO molar ratio is about 1:5-9 and wherein said polyoxyethylene/oxypropylene block copolymer has a molecular weight of about 2,000-4,000.  
   
   
       18 . Composition as recited in  claim 17  wherein said EO:PO molar ratio is about 1:9 and said molecular weight is about 3300.  
   
   
       19 . Composition as recited in  claim 15  wherein said fluoacid comprises fluotitanic acid.  
   
   
       20 . Composition as recited in  claim 15 , wherein said film forming latex polymer comprises an acrylate resin.  
   
   
       21 . Composition as recited in  claim 20  wherein said acrylate resin comprises butyl acrylate/methyl methacrylate and methacrylic acid polymers.