Method for coating metallic surfaces with a composition that is rich in polymers

Abstract

A method for coating a metallic surface with an aqueous composition for pretreating before applying another coating or for treating said metallic surface. In addition to water, the composition contains: a) at least one hydrolyzable or at least partially hydrolyzed silane; b) at least one metal chelate; c) at least one organic film former, and; d) at least one long-chain alcohol that serves as a film forming aid. The unsoiled, scoured, cleaned and/or pretreated metallic surface is brought into contact with the aqueous composition so that a film forms on the metallic surface, which is subsequently dried, compacted in part or completely by film formation and, if necessary, additionally hardened. The dried and, if necessary, additionally hardened film has a layer thickness ranging from 0.01 to 10 μm. The invention also relates to corresponding aqueous compositions.

1 - 40 . (canceled) 
     
     
         41 . A process comprising:
 contacting a metallic surface that is at least one of clean, pickled, cleaned or pretreated with an aqueous composition having a solids content to form a film on the metallic surface to form a coated substrate, which is then dried to partly or completely compact the formed dried film,
 wherein the dried film has a layer thickness in the range from 0.01 to 10 μm, for pretreatment before a further coating or for treatment, 
   wherein the aqueous composition has a pH of from 4 to 9.5 and is largely or completely free of chromium(VI) compounds,   wherein the aqueous composition comprises:   water;   a hydrolysable or at least partly hydrolyzed silane;   a metal chelate which has only a low reactivity in the aqueous composition;   a crosslinking agent based on a member selected from the group consisting of a titanium cation, a hafnium cation, a zirconium cation, a carbonate anion or and an ammonium carbonate anion;   an organic film-forming agent comprising at least one of a water-soluble organic polymer, a water-dispersible organic polymer, a water soluble organic copolymer, or a water-dispersible organic-copolymer with an acid number in the range from 3 to 250 and wherein the organic film-forming agent, based on the solids the composition, is present in an amount of >45 wt. % and contains an acid group, and
 a long-chain alcohol as a film-forming auxiliary. 
   
     
     
         42 . A process according to  claim 41 , wherein the content of the crosslinking agent in the aqueous composition is in the range from 0.01 to 3 wt. %. 
     
     
         43 . A process according to  claim 41 , wherein the aqueous composition further comprises a further component selected from the group consisting of at least one inorganic compound in particle form with an average particle diameter, measured on a scanning electron microscope, in the range from 0.005 to 0.3 μm diameter, a lubricant, an organic corrosion inhibitor, an anticorrosion pigment, an agent for neutralization of the synthetic resin; an agent for steric stabilization of the synthetic resin, an organic solvent and a siloxane. 
     
     
         44 . A process according to  claim 41 , wherein the organic film-forming agent is a synthetic resin mixture of at least one polymer or copolymer, wherein the polymer or copolymer containing a content of synthetic resin based on a member selected from the group consisting of acrylate, epoxide, ethylene, urea-formaldehyde, phenol, polyester, polyurethane, styrene, styrene-butadiene and vinyl. 
     
     
         45 . A process according to  claim 41 , wherein the organic film-forming agent comprises as a synthetic resin a content of organic polymer, copolymer, or mixtures thereof based on a member selected from the group consisting of polyethyleneimine, polyvinyl alcohol, polyvinylphenol, polyvinylpyrrolidone and polyaspartic acid. 
     
     
         46 . A process according to  claim 41 , wherein the organic film-forming agent contains a content of at least one copolymer with an acid number in the range from 3 to 80, in particular to the extent of at least 50 wt. % of the synthetic resins added. 
     
     
         47 . A process according to  claim 41 , wherein the organic film-forming agent contains at least one component based on a member selected from the group consisting of
 acrylic-polyester-polyurethane copolymer, acrylic-polyester-polyurethane-styrene copolymer,   acrylic acid ester,   acrylic acid ester-methacrylic acid ester, optionally with free acids or acrylonitrile,   ethylene-acrylic mixture,   ethylene-acrylic copolymer,   ethylene-acrylic-polyester copolymer,   ethylene-acrylic-polyurethane copolymer,   ethylene-acrylic-polyester-polyurethane copolymer,   ethylene-acrylic-polyester-polyurethane-styrene copolymer,   ethylene-acrylic-styrene copolymer,   polyester resins with free carboxyl groups combined with melamine-formaldehyde resins,   a synthetic resin mixture or/and copolymer based on acrylate and styrene,   a synthetic resin mixture or/and copolymer based on styrene-butadiene,   a synthetic resin mixture or/and copolymer of acrylate and epoxide,   based on an acrylic-modified polyester containing carboxyl groups together with melamine-formaldehyde and ethylene-acrylic copolymer,   polycarbonate-polyurethane,   polyester-polyurethane,   styrene,   styrene-vinyl acetate,   vinyl acetate,   vinyl ester and   vinyl ether.   
     
     
         48 . A process according to  claim 41 , wherein at least 30 wt. % of the organic film-forming agent added comprises a film-formable thermoplastic resin. 
     
     
         49 . A process according to  claim 41 , wherein the molecular weights of the synthetic resins added are in the range of at least 1,000 u. 
     
     
         50 . A process according to  claim 41 , wherein the acid groups of the synthetic resins are stabilized with a member selected from the group consisting of ammonia, an amine and an alkali metal compound. 
     
     
         51 . A process according to  claim 41 , wherein the aqueous composition contains 0.1 to 980 g/l of the organic film-forming agent. 
     
     
         52 . A process according to  claim 41 , wherein the silane is selected from the group consisting of acyloxysilane, alkoxysilane, a silane with at least one amino group, a silane having at least one succinic acid group, a silane having a succinic acid anhydride group, a bis-silyl-silane, a silane with at least one epoxide group, a (meth)acrylato-silane, a multi-silyl-silane, a ureidosilane and a vinylsilane, or wherein the silane is a silanol or siloxane of a composition which corresponds chemically thereto. 
     
     
         53 . A process according to  claim 41 , wherein the composition contains at least one silane chosen from the group consisting of
 glycidoxyalkyltrialkoxysilane,   methacryloxyalkyltrialkoxysilane,   (trialkoxysilyl)alkyl-succinic acid-silane,   aminoalkylaminoalkylalkyldialkoxysilane,   (epoxycycloalkyl)alkyltrialkoxysilane,   bis-(trialkoxysilylalkyl)amine,   bis-(trialkoxysilyl)ethane,   (epoxyalkyl)trialkoxysilane,   aminoalkyltrialkoxysilane,   ureidoalkyltrialkoxysilane,   N-(trialkoxysilylalkyl)alkylenediamine,   N-(aminoalkyl)aminoalkyltrialkoxysilane,   N-(trialkoxysilylalkyl)dialkylenetriamine,   poly(aminoalkyl)alkyldialkoxysilane,   tris(trialkoxysilyl)alkyl isocyanurate,   ureidoalkyltrialkoxysilane and   acetoxysilane.   
     
     
         54 . A process according to  claim 41 , wherein the composition contains at least one silane chosen from the group consisting of
 3-glycidoxypropyltriethoxysilane,   3-glycidoxypropyltrimethoxysilane,   3-methacryloxypropyltriethoxysilane,   3-methacryloxypropyltrimethoxysilane,   3-(triethoxysilyl)propyl-succinic acid-silane,   aminoethylaminopropylmethyldiethoxysilane aminoethylaminopropylmethyldimethoxysilane,   beta-(3,4-epoxycyclohexyl)ethyltriethoxy-silane,   beta-(3,4-epoxycyclohexyl)ethyltrimethoxy-silane,   beta-(3,4-epoxycyclohexyl)methyltriethoxy-silane,   beta-(3,4-epoxycyclohexyl)methyltrimethoxy-silane,   gamma-(3,4-epoxycyclohexyl)propyltriethoxysilane,   gamma-(3,4-epoxycyclohexyl)propyltrimethoxysilane,   bis(triethoxysilylpropyl)amine,   bis(trimethoxysilylpropyl)amine,   (3,4-epoxybutyl)triethoxysilane,   (3,4-epoxybutyl)trimethoxysilane,   gamma-am inopropyltriethoxysilane,   gamma-aminopropyltrimethoxysilane,   gamma-ureidopropyltrialkoxysilane,   N-(3-(trimethoxysilyl)propyl)ethylenediamine,   N-beta-(aminoethyl)-gamma-aminopropyltri-ethoxy-silane,   N-beta-(aminoethyl)-gamma-aminopropyltri-methoxysilane,   N-(gamma-triethoxysilylpropyl)diethylene-triamine,   N-(gamma-trimethoxysilylpropyl)diethylene-triamine,   N-(gamma-triethoxysilylpropyl)dimethylene-triamine,   N-(gamma-trimethoxysilylpropyl)dimethylene-triamine,   poly(aminoalkyl)ethyldialkoxysilane,   poly(aminoalkyl)methyldialkoxysilane,   tris(3-(triethoxysilyl)propyl) isocyanurate tris(3-(trimethoxysilyl)propyl) isocyanurate and   vinyltriacetoxysilane.   
     
     
         55 . A process according to  claim 41 , wherein the content of the at least one silane in the aqueous composition, including any reaction products formed therefrom, is 0.1 to 50 g/l. 
     
     
         56 . A process according to  claim 41 , wherein the at least one metal chelate is chosen from chelate complexes based on a member selected from the group consisting of an acetylacetonate, an acetoacetate, an acetonate, an alkylenediamine, an amine, a lactate, a carboxylic acid, a citrate and a glycol, wherein the content of the at least one chelate in the aqueous composition, including any reaction products formed therefrom, is from 0.1 to 80 g/l. 
     
     
         57 . A process according to  claim 41 , wherein the at least one metal chelate is a member selected from the group consisting of acetylacetonate,
 alkali metal lactate,   alkanolamine,   alkyl acetoacetate,   alkylenediamine tetraacetate,   ammonium lactate,   citrate,   dialkyl citrate,   dialkyl ester-citrate,   dialkylenetriamine,   diisoalkoxybisalkyl acetoacetate,   diisopropoxybisalkyl acetoacetate,   di-n-alkoxy-bisalkyl acetoacetate,   hydroxyalkylenediamine triacetate,   trialkanolamine and   trialkylenetetramine.   
     
     
         58 . A process according to  claim 41 , wherein the inorganic compound is in the form of particles, and wherein the particles are added as a finely divided powder, a dispersion or a suspension. 
     
     
         59 . A process according to  claim 41 , wherein inorganic compound is based on at least one member selected from the group consisting of aluminum, barium, cerium, calcium, lanthanum, silicon, titanium, yttrium, zinc and zirconium. 
     
     
         60 . A process according to  claim 41 , wherein the inorganic compound is selected from the group consisting of aluminum oxide, barium sulfate, cerium dioxide, silicon dioxide, silicate, titanium oxide, yttrium oxide, zinc oxide and zirconium oxide. 
     
     
         61 . A process according to  claim 41 , wherein the aqueous composition contains 0.1 to 500 g/l of the at least one inorganic compound in particle form. 
     
     
         62 . A process according to  claim 41 , wherein the aqueous composition contains at least one organic corrosion inhibitor based on a member selected from the group consisting of an amine, a TPA-amine complex, a cyanic acid, a metal salt of a sulfonic acid, an amino and transition metal complex of toluenepropionic acid, 2-mercapto-benzothiazolyl-succinic acid, an ammonium salt, a conductive polymer and a thiol, the content of organic corrosion inhibitors in the aqueous composition preferably being in the range from 0.01 to 5 wt. %. 
     
     
         63 . A process according to  claim 41 , wherein the crosslinking agent is basic. 
     
     
         64 . A process according to  claim 41 , wherein no inorganic acids or organic carboxylic acids are added to the aqueous composition. 
     
     
         65 . A process according to  claim 41 , wherein at least one long-chain alcohol is selected from the group consisting of a diol, a butanediol, a propanediol, a decanediol, a butyl glycol, a butyl diglycol, an ester-alcohol, an ethylene glycol, an ethylene glycol ether, a glycol ether, a polyether, a polyethylene glycol, a polyethylene glycol ether, a polyglycol, a polypropylene glycol, a propylene glycol, a propylene glycol ether, a polypropylene glycol ether, a glycol ether and a trimethylpentanediol diisobutyrate. 
     
     
         66 . A process according to  claim 41 , wherein wax is selected from the group consisting of a paraffin, a polyethylene and a polypropylene. 
     
     
         67 . A process according to  claim 41 , wherein the lubricant comprises a wax and at least one member selected from the group consisting of a polymer and a copolymer. 
     
     
         68 . A process according to  claim 41 , wherein the coating is cured partly by drying and film formation and partly by actinic radiation, cationic polymerization and thermal crosslinking.