Process for coating metallic surfaces with an aqueous composition, and this composition

Abstract

The invention relates to a process for coating metallic surfaces with a composition containing silane/silanol/siloxane/polysiloxane, the composition consisting essentially of a) at least one compound selected from silanes, silanols, siloxanes and polysiloxanes, b) at least two compounds selected from compounds containing titanium, hafnium, zirconium, aluminium and/or boron, and optionally c) at least one type of cation selected from cations of metals of subgroups 1 to 3 and 5 to 8, including lanthanides, and of main group 2 of the periodic table of the elements, and/or at least one corresponding compound, d) at least one organic compound selected from monomers, oligomers, polymers, copolymers and block copolymers, and/or e) at least one substance that influences the pH, as well as f) water, and g) optionally at least one organic solvent. The invention further relates to corresponding aqueous compositions.

1 .- 23 . (canceled) 
     
     
         24 . A process comprising coating a metallic surface with a composition, wherein said composition comprises:
 a) from 0.02 to 1 g/L of at least one compound selected from the group consisting of a silane, a silanol, a siloxane and a polysiloxane, wherein the silane, the silanol, the siloxane or the polysiloxane contains at least one group selected from the group consisting of an amino group, a urea group and a ureido group;   b) at least two complex fluorides of formula MeF 6  wherein Me is a metal selected from the group consisting of titanium, hafnium, zirconium, aluminum and boron;   water, and   c) at least one cation selected from the group consisting of cerium, chromium, iron, calcium cobalt, copper, magnesium, manganese, molybdenum, nickel, niobium, tantalum, yttrium, zinc, and tin;   
       wherein the total amount of the complex fluorides ranges from 0.01 to 100 g/L; and 
       wherein the composition contains no organic solvent. 
     
     
         25 . The process of  claim 24 , wherein prior to drying, at least one member selected from the group consisting of a lacquer, a primer and an adhesive is applied to the coating. 
     
     
         26 . A process comprising coating a plurality of metallic surfaces in a bath of a composition comprising
 a) at least one compound selected from the group consisting of a silane, a silanol, a siloxane and a polysiloxane ranging from 0.02 to 1 g/L and wherein the silane, the silanol, the siloxane or the polysiloxane has at least one member selected from the group consisting of an amino group, a urea group and a ureido group;   b) at least two complex fluorides of formula MeF 6  wherein Me is a metal selected from the group consisting of titanium, hafnium, zirconium, aluminum and boron;   water,   c) at least one cation selected from the group consisting of cerium, chromium, iron, calcium cobalt, copper, magnesium, manganese, molybdenum, nickel, niobium, tantalum, yttrium, zinc; and, and   d) at least one organic compound selected from monomers, oligomers, polymers, copolymers and block copolymers based on acrylic or urethane in a weight ratio of from 1:0.05 to 1:2 of compounds based on silane, silanol, siloxane or polysiloxane, calculated on the basis of the corresponding silanols, to compounds based on organic polymers, calculated as added solids, in the composition; and   
       rinsing the coating when freshly applied and prior to thorough drying; wherein said plurality of metallic surfaces comprise at least two different metals and said plurality of surfaces are coated in the same said bath, wherein the composition has a free fluoride content in the range of from 0.01 to 1 g/L, and wherein the total amount of the complex fluorides ranges from 0.01 to 100 g/L; and wherein the composition contains no organic solvent. 
     
     
         27 . A process according to  claim 26 , wherein said weight ratio is 1:0.05. 
     
     
         28 . A process according to  claim 26 , wherein said weight ratio is 1:2. 
     
     
         29 . A process according to  claim 24 , further comprising the step of applying a lacquer, a lacquer-like coating, a primer or an adhesive to the freshly applied silane-based coating that have not yet dried thoroughly. 
     
     
         30 . A process according to  claim 24 , wherein the rinsing is conducted with demineralized water. 
     
     
         31 . A process according to  claim 24 , wherein the coated surface is dried after rinsing. 
     
     
         32 . A process according to  claim 31 , wherein the coated surface is dried after rinsing at a temperature of 120° C. 
     
     
         33 . A process comprising coating a metallic surface with a composition, wherein said composition comprises:
 at least one silane, siloxane or polysiloxane having at least one member selected from the group consisting of an amino group, a urea group and a ureido group;   at least two compounds complex fluorides of formula MeF 6  wherein Me is a metal selected from the group consisting of titanium, hafnium, zirconium, aluminum and boron;   water, and   at least one cation selected from the group consisting of cerium, chromium, iron, calcium cobalt, copper, magnesium, manganese, molybdenum, nickel, niobium, tantalum, yttrium, zinc, and tin,   
       wherein the total amount of the complex fluorides ranges from 0.01 to 100 g/L; and 
       wherein the composition contains no organic solvent 
     
     
         34 . The process of  claim 24 , wherein the drying is conducted at a temperature above 70° C.