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

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, which is then dried to partly or completely compact the formed film, and optionally curing the film,

• wherein the dried and optionally cured film has a layer thickness in the range from 0.01to 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, and comprises water and:
• a) at least one hydrolyzable or at least partly hydrolyzed silane, wherein said silane is an epoxy silane
• b) at least one metal chelate selected from the group consisting of an acetoacetate, an acetonate, an alkylenediamine, an amine, a lactacte, a carboxylic acid, a citrate and a glycol, wherein the content of the at least one chelate in the aqueous composition, including the any reaction products formed therefrom, is from 0.1 to 80g/l;
• c) at least one organic film-forming agent with an acid number of from 13 to 250which contains at least one of a water soluble organic polymer, a water dispersible organic polymer, a water soluble copolymer, or a water dispersible copolymer and wherein the organic film-forming agent, based on the solids content of the composition, is present in an amount of >45 wt. %,
• wherein said organic film-forming agent further comprises at least one 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 at least one of 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 mixture or copolymer based on acrylate and styrene,
• a mixture or a copolymer based on styrene-butadiene,
• a synthetic resin mixture or copolymer of acrylate and epoxide,
• 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;
• and
• d) at least one long-chain alcohol as a film-forming auxiliary,
• wherein the aqueous composition further comprises a crosslinking agent based on a hafnium cation, wherein the content of the crosslinking agent in the aqueous composition is in the range from 0.01 to 3 wt. %.

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, 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, and wherein the aqueous composition comprises water and:
• a) at least one hydrolyzable or at least partly hydrolyzed silane, wherein said silane is an epoxy silane;
• b) a metal chelate selected from the group consisting of a metal lactate;
• a metal ammonium lactate, a metal citrate, a metal lactate, a metal dialkylcitrate, and a metal dialkylester-citrate;
• c) an organic film-forming agent which comprises 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 content of organic film-forming agent, based on the solids the composition, is present in an amount of >45 wt. %″;
• and
• d) at least one long-chain alcohol,
• wherein the aqueous composition further comprises a crosslinking agent based on a hafnium cation, wherein the content of the crosslinking agent in the aqueous composition is in the range from 0.01 to 3 wt. %.

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, 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, and comprises water and:
• a) at least one hydrolyzable or at least partly hydrolyzed silane, wherein said silane is an epoxy silane;
• b) a metal chelate selected from the group consisting of a metal ammonium lactate, a metal lactate, a metal citrate, a metal dialkylcitrate, and a metal dialkylester-citrate;
• c) a copolymer with an acid number in the range from 3 to 250 and wherein the content of organic film-forming agent, based on the solids the composition, is present in an amount of >45wt. %;
• and
• d) at least one long-chain alcohol,
• wherein the aqueous composition further comprises a crosslinking agent based on a hafnium cation, wherein the content of the crosslinking agent in the aqueous composition is in the range from 0.01 to 3 wt. %.

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, which is then dried to partly or completely compact the formed 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, and comprises water and:
• a) at least one hydrolyzable or at least partly hydrolyzed silane, wherein said silane is an epoxy silane;
• b) at least one metal chelate based on
• 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;
• c) at least one organic film-forming agent which contains at least one of a water soluble polymer, a water dispersible polymer, a water soluble organic polymer, a water soluble organic copolymer and a water dispersible copolymer with an acid number in the range from 3 to 250, wherein the content of organic film-forming agent, based on the solids content of the composition, is >45 wt. %, and
• wherein said organic film-forming agent further comprises at least one 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 at least one of 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 mixture or copolymer based on acrylate and styrene,
• a mixture or copolymer based on styrene-butadiene,
• a mixture or copolymer of acrylate and epoxide,
• 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;
• and
• d) at least one long-chain alcohol as a film-forming auxiliary,
• wherein the aqueous composition further comprises a crosslinking agent based on a hafnium cation, wherein the content of the crosslinking agent in the aqueous composition is in the range from 0.01 to 3 wt. %.

A process for coating a metallic surface with an aqueous composition, the process comprising contacting the clean, pickled, cleaned or pretreated metallic surface with the aqueous composition with metallic surface to form a film thereon, wherein the film is then dried,

• wherein the dried film has a layer thickness in the range from 0.01 to 10 μm free from chromium(VI) compounds, for pretreatment before a further coating or for treatment,
• wherein the aqueous composition comprises water and,
• a) a hydrolysable or at least partly hydrolyzed silane,
• b) a metal chelate which has only a low reactivity in the aqueous composition,
• c) an organic film-forming agent which contains at least one water soluble or water dispersible organic polymer or/and copolymer with an acid number in the range from 3 to 250and wherein the content of organic film-forming agent, based on the solids content of the composition, is >45 wt. %, and
• d) at least one long-chain alcohol as a film-forming auxiliary,
• wherein the aqueous composition further comprises a crosslinking agent based on a hafnium cation, wherein the content of the crosslinking agent in the aqueous composition is in the range from 0.01 to 3 wt. %.