Method for providing coating systems with corrosion-protective properties

Abstract

The present invention is directed to a method for producing a coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably in the form of a dispersion (i.e. emulsion or latex, respectively), as well as to coating system thus produced and to its various applications. The resulting coating system provides superior properties with respect to corrosion protection, on the one hand, and adhesion to metal surfaces, on the other hand, while at the same time being environmentally compatible and easy to use and to apply and being producible in an economic way.

1 . A method for producing a coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion),
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties (i), (ii), (iii) and optionally (iv) according to the following definition and each being different from one another:   (i) a first ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (i)  ranging from 30° C. to 200° C., especially from 40° C. to 150° C.,   (ii) a second ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (ii)  ranging from −100° C. to −10° C., especially from −60° C. to −20° C.,   (iii) a phosphate-group containing methacrylic monomer (PAM), wherein the phosphate-group containing methacrylic monomer (PAM) is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, and   (iv) an optional further monomer selected from (1) perfluoroalkyl (meth)acrylates (PFA), (2) C 12 -C 22 -alkyl(meth)acrylates, especially C 12 -C 22 -alkyl(meth)acrylates forming semicrystalline homopolymers, preferably stearyl(meth)acrylates (SMA), and (3) mesogenic monomers comprising ethylenically unsaturated monomeric moieties, especially mesogenic monomers comprising (meth)acrylate monomeric units comprising side-chains and/or ester groups bearing mesogenic functionalities, especially biphenyl mesogen groups;   wherein:   (a) in a first stage (step), an emulsion prepolymerization of at least part of at least one of monomers (i), (ii) and/or optionally (iv) is performed in the absence of monomer (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then   (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and the remainder of monomers (i), (ii) and optionally (iv), if any, are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i), (ii), (iii) and optionally (iv).   
     
     
         2 . The method according to  claim 1 ,
 wherein moiety (i) and/or (i) the first ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (i)  ranging from 30° C. to 200° C., especially from 40° C. to 150° C., is selected from the group consisting of:   (1) linear, branched or cycloaliphatic C 1 -C 22 -alkyl(meth)acrylates, especially methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)-acrylate, lauryl(meth)acrylate, 2-ethylhexyl(meth)acrylate, stearyl(meth)acrylate, cyclohexyl(meth)acrylate, isobornyl(meth)acrylate and tert-butyl(meth)acrylate;   (2) aryl(meth)acrylates, especially benzyl(meth)acrylate and phenylacrylate, especially wherein the aryl radicals may be each unsubstituted or substituted with up to four substituents;   (3) mono(meth)acrylates of ethers, polyethyleneglycols, polypropyleneglycols or mixed polyethylene/propylene glycols each comprising 5 to 80 carbon atoms, especially tetrahydrofurfuryl(meth)acrylate, methoxyethoxyethyl(meth)acrylate, 1-butoxypropyl(meth)acrylate, cyclohexyloxymethyl(meth)acrylate, methoxymethoxy-ethyl(meth)acrylate, benzyloxymethyl(meth)acrylate, furfuryl(meth)acrylate, 2-butoxyethyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate, allyloxymethyl(meth)-acrylate, 1-ethoxybutyl(meth)acrylate, 1-ethoxyethyl(meth)acrylate, ethoxy-methyl(meth)acrylate, poly(ethyleneglycol)methylether(meth)acrylate and poly-(propyleneglycol)methylether(meth)acrylate;   (4) aminoalkyl(meth)acrylates, especially N,N-dimethylaminoethyl(meth)acrylate, 2-trimethylammoniumethyl(meth)acrylatchloride and N,N-dimethyl-aminopropyl(meth)acrylate;   (5) oxiranyl(meth)acrylates, especially 2,3-epoxybutyl(meth)acrylate, 3,4-epoxybutyl-(meth)acrylate and glycidyl(meth)acrylate;   (6) styrenes and substituted styrenes, especially α-methylstyrenes, 4-methylstyrenes, 4-vinylbenzoic acid and sodium-4-vinylbenzene sulfonate;   (7) (meth)acrylonitrile;   (8) ethylenically unsaturated sulfonic acids and sulfates and salts thereof, especially potassium[3-((meth)acryloyloxy)propyl]sulfonate and ammonium[2-((meth)acryloyloxy)ethyl]sulfate;   (9) vinylesters of carboxylic acids comprising 1 to 20 carbon atoms, especially vinylacetate;   (10) vinylesters of versatic acids;   (11) (meth)acrylamide;   (12) N-alkyl- and N,N-dialkyl-substituted (meth)acrylamides comprising linear, branched or cycloaliphatic C 1 -C 22 -alkyl groups, especially N-(tert-butyl)acrylamide and N,N-dimethylacrylamide.   
     
     
         3 . The method according to  claim 1  or  claim 2 ,
 wherein moiety (i) and/or (i) the first ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (l)  ranging from 30° C. to 200° C., especially from 40° C. to 150° C., is selected from the group consisting of: 
 (1) linear, branched or cycloaliphatic C 1 -C 22 -alkylmethacrylates, especially methylmethacrylate, ethylmethacrylate, n-butylmethacrylate, iso-butylmethacrylate, laurylmethacrylate, 2-ethylhexylmethacrylate, stearylmethacrylate, cyclohexylmethacrylate, isobornylmethacrylate and tert-butylmethacrylate; 
 (2) arylmethacrylates, especially benzylmethacrylate and phenylacrylate, especially wherein the aryl radicals are each unsubstituted or substituted with up to four substituents; 
 (3) monomethacrylates of ethers, polyethyleneglycols, polypropyleneglycols or mixed polyethylene/propylene glycols each comprising 5 to 80 carbon atoms, especially tetrahydrofurfurylmethacrylate, methoxyethoxyethylmethacrylate, 1-butoxypropylmethacrylate, cyclohexyloxymethylmethacrylate, methoxymethoxyethylmethacrylate, benzyloxymethylmethacrylate, furfurylmethacrylate, 2-butoxyethylmethacrylate, 2-ethoxyethylmethacrylate, allyloxymethylmethacrylate, 1-ethoxybutylmethacrylate, 1-ethoxyethylmethacrylate, ethoxymethylmethacrylate, poly-(ethyleneglycol)methylethermethacrylate and poly(propyleneglycol)methylethermethacrylate; 
 (4) aminoalkylmethacrylates, especially N,N-dimethylaminoethylmethacrylate, 2-trimethylammoniumethylmethacrylatchloride and N,N-dimethylaminopropylmethacrylate; 
 (5) oxiranylmethacrylates, especially 2,3-epoxybutylmethacrylate, 3,4-epoxybutylmethacrylate and glycidylmethacrylate; 
 (6) styrenes and substituted styrenes, especially α-methylstyrenes, 4-methylstyrenes, 4-vinylbenzoic acid and sodium-4-vinylbenzene sulfonate; 
 (7) methacrylonitrile; 
 (8) ethylenically unsaturated sulfonic acids and sulfates and salts thereof, especially potassium[3-(methacryloyloxy)propyl]sulfonate and ammonium[2-(methacryloyloxy)-ethyl]sulfate; 
 (9) vinylesters of carboxylic acids comprising 1 to 20 carbon atoms, especially vinylacetate; 
 (10) vinylesters of versatic acids; 
 (11) methacrylamide; 
 (12) N-alkyl- and N,N-dialkyl-substituted methacrylamides comprising linear, branched or cycloaliphatic C 1 -C 22 -alkyl groups, especially N-(tert-butyl)acrylamide and N,N-dimethylacrylamide. 
 
     
     
         4 . The method according to any of  claims 1  to  3 ,
 wherein moiety (i) and/or (i) the first ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (l)  ranging from 30° C. to 200° C., especially from 40° C. to 150° C., is methyl methacrylate (MMA). 
 
     
     
         5 . The method according to any of  claims 1  to  4 ,
 wherein moiety (ii) and/or (ii) the second ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (ii)  ranging from −100° C. to −10° C., especially from −60° C. to −20° C., is selected from the group consisting of: 
 (1) linear, branched or cycloaliphatic C 1 -C 22 -alkyl(meth)acrylates, especially methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate, iso-butyl(meth)-acrylate, lauryl(meth)acrylate, 2-ethylhexyl(meth)acrylate, stearyl(meth)acrylate, cyclohexyl(meth)acrylate, isobornyl(meth)acrylate and tert-butyl(meth)acrylate; 
 (2) aryl(meth)acrylates, especially benzyl(meth)acrylate and phenylacrylate, especially wherein the aryl radicals are each unsubstituted or substituted with up to four substituents; 
 (3) mono(meth)acrylates of ethers, polyethyleneglycols, polypropyleneglycols or mixed polyethylene/propylene glycols each comprising 5 to 80 carbon atoms, especially tetrahydrofurfuryl(meth)acrylate, methoxyethoxyethyl(meth)acrylate, 1-butoxypropyl(meth)acrylate, cyclohexyloxymethyl(meth)acrylate, methoxymethoxy-ethyl(meth)acrylate, benzyloxymethyl(meth)acrylate, furfuryl(meth)acrylate, 2-butoxyethyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate, allyloxymethyl(meth)-acrylate, 1-ethoxybutyl(meth)acrylate, 1-ethoxyethyl(meth)acrylate, ethoxymethyl-(meth)acrylate, poly(ethyleneglycol)methylether(meth)acrylate and poly(propylene-glycol)methylether(meth)acrylate; 
 (4) aminoalkyl(meth)acrylates, especially N,N-dimethylaminoethyl(meth)acrylate, 2-trimethylammoniumethyl(meth)acrylatchloride and N,N-dimethyl-aminopropyl(meth)acrylate; 
 (5) oxiranyl(meth)acrylates, especially 2,3-epoxybutyl(meth)acrylate, 3,4-epoxybutyl-(meth)acrylate and glycidyl(meth)acrylate; 
 (6) styrenes and substituted styrenes, especially α-methylstyrenes, 4-methylstyrenes, 4-vinylbenzoic acid and sodium-4-vinylbenzene sulfonate; 
 (7) (meth)acrylonitrile; 
 (8) ethylenically unsaturated sulfonic acids and sulfates and salts thereof, especially potassium[3-((meth)acryloyloxy)propyl]sulfonate and ammonium[2-((meth)acryloyloxy)ethyl]sulfate; 
 (9) vinylesters of carboxylic acids comprising 1 to 20 carbon atoms, especially vinylacetate; 
 (10) vinylesters of versatic acids; 
 (11) (meth)acrylamide; 
 (12) N-alkyl- and N,N-dialkyl-substituted (meth)acrylamides comprising linear, branched or cycloaliphatic C 1 -C 22 -alkyl groups, especially N-(tert-butyl)acrylamide and N,N-dimethylacrylamide. 
 
     
     
         6 . The method according to any of  claims 1  to  5 ,
 wherein moiety (ii) and/or (ii) the second ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (ii)  ranging from −100° C. to −10° C., especially from −60° C. to −20° C., is selected from the group consisting of: 
 (1) linear, branched or cycloaliphatic C 1 -C 22 -alkylacrylates, especially methylacrylate, ethylacrylate, n-butylacrylate, iso-butylacrylate, laurylacrylate, 2-ethylhexylacrylate, stearylacrylate, cyclohexylacrylate, isobornylacrylate and tert-butylacrylate; 
 (2) arylacrylates, especially benzylacrylate and phenylacrylate, especially wherein the aryl radicals are each unsubstituted or substituted with up to four substituents; 
 (3) monoacrylates of ethers, polyethyleneglycols, polypropyleneglycols or mixed polyethylene/propylene glycols each comprising 5 to 80 carbon atoms, especially tetrahydrofurfurylacrylate, methoxyethoxyethylacrylate, 1-butoxypropylacrylate, cyclohexyloxymethylacrylate, methoxymethoxyethylacrylate, benzyloxymethylacrylate, furfurylacrylate, 2-butoxyethylacrylate, 2-ethoxyethylacrylate, allyloxymethylacrylate, 1-ethoxybutylacrylate, 1-ethoxyethylacrylate, ethoxymethylacrylate, poly(ethylene-glycol)methyletheracrylate and poly(propyleneglycol)methyletheracrylate; 
 (4) aminoalkylacrylates, especially N,N-dimethylaminoethylacrylate, 2-trimethyl-ammoniumethylacrylatchloride and N,N-dimethylaminopropylacrylate; 
 (5) oxiranylacrylates, especially 2,3-epoxybutylacrylate, 3,4-epoxybutylacrylate and glycidylacrylate; 
 (6) styrenes and substituted styrenes, especially α-methylstyrenes, 4-methylstyrenes, 4-vinylbenzoic acid and sodium-4-vinylbenzene sulfonate; 
 (7) acrylonitrile; 
 (8) ethylenically unsaturated sulfonic acids and sulfates and salts thereof, especially potassium[3-(acryloyloxy)propyl]sulfonate and ammonium[2-(acryloyloxy)ethyl]-sulfate; 
 (9) vinylesters of carboxylic acids comprising 1 to 20 carbon atoms, especially vinylacetate; 
 (10) vinylesters of versatic acids; 
 (11) acrylamide; 
 (12) N-alkyl- and N,N-dialkyl-substituted acrylamides comprising linear, branched or cycloaliphatic C 1 -C 22 -alkyl groups, especially N-(tert-butyl)acrylamide and N,N-dimethylacrylamide. 
 
     
     
         7 . The method according to any of  claims 1  to  6 ,
 wherein moiety (ii) and/or (ii) the second ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (ii)  ranging from −100° C. to −10° C., especially from −60° C. to −20° C., is butyl acrylate (BA). 
 
     
     
         8 . The method according to any of  claims 1  to  7 ,
 wherein moiety (iv) and/or the optional further monomer (iv) is selected from perfluoroalkyl (meth)acrylates (PFA) and stearyl(meth)acrylates (SMA). 
 
     
     
         9 . The method according to any of  claims 1  to  8 ,
 wherein moiety (i) and/or (i) the first ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (i)  ranging from 30° C. to 200° C., especially from 40° C. to 150° C., is methyl methacrylate (MMA); and/or 
 wherein moiety (ii) and/or (ii) the second ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (ii)  ranging from −100° C. to −10° C., especially from −60° C. to −20° C., is butyl acrylate (BA); and/or 
 wherein moiety (iv) and/or the optional further monomer (iv) is selected from perfluoroalkyl (meth)acrylates (PFA) and stearyl(meth)acrylates (SMA). 
 
     
     
         10 . The method according to any of  claims 1  to  9 ,
 wherein moiety (i) and/or (i) the first ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (I)  ranging from 30° C. to 200° C., especially from 40° C. to 150° C., is methyl methacrylate (MMA); and 
 wherein moiety (ii) and/or (ii) the second ethylenically unsaturated monomer, the homopolymer of which has a glass transition temperature Tg (i)  ranging from −100° C. to −10° C., especially from −60° C. to −20° C., is butyl acrylate (BA); and 
 wherein moiety (iv) and/or the optional further monomer (iv) is selected from perfluoroalkyl (meth)acrylates (PFA) and stearyl(meth)acrylates (SMA). 
 
     
     
         11 . A method for producing a coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion), especially method according to any of  claims 1  to  10 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) an optional further monomer selected from perfluoroalkyl (meth)acrylates (PFA) and stearyl(meth)acrylates (SMA), 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of at least part of at least one of monomers (i), (ii) and/or optionally (iv) is performed in the absence of monomer (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and the remainder of monomers (i), (ii) and optionally (iv), if any, are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) an optional further monomer selected from perfluoroalkyl (meth)acrylates (PFA) and stearyl(meth)acrylates (SMA), 
 wherein (iii) the phosphate-group containing methacrylic monomer (PAM) is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates. 
 
     
     
         12 . The method according to any of  claims 1  to  11 ,
 wherein the first stage (step) (a) is performed in the presence of at least one polymerization initiator, especially a radical polymerization initiator, preferably selected from the group consisting of thermal polymerization initiators, redox polymerization initiators and combinations thereof, particularly inorganic and/or organic persulfates, peroxides, hydroperoxides, perbenzoates, peralkanoates, azoinitiators and combinations thereof, more preferably selected from the group consisting of inorganic and/or organic persulfates and azobisisobutyronitrile (AIBN), particularly selected from the group consisting of inorganic persulfates of alkali or earth alkaline metals and azobisisobutyronitrile (AIBN); and/or 
 wherein the first stage (step) (a) is performed in the presence of at least one surfactant (emulsifier), especially an anionic or non-ionic surfactant, especially selected from the group consisting of anionic organic sulfates and sulfonates and non-ionic alkylene oxides, especially ethylene and/or propylene oxides, and combinations thereof, preferably selected from the group consisting of organic sulfonates, particularly dodecyl diphenyloxide disulfonates; and/or 
 wherein the first stage (step) (a) is performed in the presence of at least one buffer, especially an inorganic carbonate or hydrogen carbonate buffer; and/or 
 wherein the first stage (step) (a) is performed under neutral or acidic conditions, preferably under acidic conditions; and/or 
 wherein the first stage (step) (a) is performed in a water-based (waterborne) liquid milieu or carrier, especially wherein the water-based (waterborne) liquid milieu or carrier additionally comprises at least one polymerization initiator and/or at least one surfactant and/or at least one buffer, preferably each as defined in any of the preceding claims, and/or optionally at least one further additive; and/or 
 wherein the first stage (step) (a) is performed at elevated temperatures and/or wherein the first stage (step) (a) is performed at a temperature in the range of from 40° C. to 200° C., especially in the range of from 50° C. to 150° C., preferably in the range of from 55° C. to 130° C., more preferably in the range of from 60° C. to 100° C.; and/or 
 wherein the first stage (step) (a) is performed at ambient pressure (1 bar or 101.325 kPa), at reduced pressure or at elevated pressure, preferably at ambient pressure (1 bar or 101.325 kPa); and/or 
 wherein the first stage (step) (a) is performed for a duration in the range of from 0.01 to 24 hours, especially in the range of from 0.1 to 12 hours, preferably in the range of from 0.5 to 6 hours, more preferably in the range of from 0.75 to 4 hours; and/or 
 wherein the first stage (step) (a) is performed until a solid content, based on the total weight of the emulsion prepolymerization product resulting from stage (a), of at least 5% by weight, especially of at least 7.5% by weight, preferably of at least 10% by weight, more preferably of at least 12.5% by weight, even more preferably of at least 15% by weight, most preferably of at least 20% by weight, has been reached and/or wherein the first stage (step) (a) is performed until a solid content, based on the total weight of the emulsion prepolymerization product resulting from stage (a), in the range of from 5 to 80% by weight, especially in the range of from 7.5 to 60% by weight, preferably in the range of from 10 to 50% by weight, more preferably in the range of from 12.5 to 40% by weight, even more preferably in the range of from 15 to 35% by weight, most preferably in the range of from 20 to 30% by weight, has been reached; and/or 
 wherein the first stage (step) (a) is performed in an at least essentially inert atmosphere, especially selected from nitrogen and noble gases, especially nitrogen; and/or 
 wherein the first stage (step) (a) is performed as an emulsion polymerization, particularly as a radical emulsion polymerization, especially as a miniemulsion polymerization, preferably with diameter sizes of the dispersed phase from 50 nm to 1 micrometer. 
 
     
     
         13 . The method according to any of  claims 1  to  12 ,
 wherein, after the first stage (step) (a) and/or before the second stage (step) (b), the emulsion prepolymerization product resulting from stage (a) and/or the polymerization milieu used in the second stage (step) (b) is/are neutralized or alkalized, preferably neutralized, or is/are adjusted to a neutral or slightly alkaline pH value, preferably to a neutral pH value, particularly by use of an alkaline agent. 
 
     
     
         14 . The method according to any of  claims 1  to  13 ,
 wherein the second stage (step) (b) is performed in the presence of at least one polymerization initiator, especially a radical polymerization initiator, preferably selected from the group consisting of thermal polymerization initiators, redox polymerization initiators and combinations thereof, particularly inorganic and/or organic persulfates, peroxides, hydroperoxides, perbenzoates, peralkanoates, azoinitiators and combinations thereof, more preferably selected from the group consisting of inorganic and/or organic persulfates and azobisisobutyronitrile (AIBN), particularly selected from the group consisting of inorganic persulfates of alkali or earth alkaline metals and azobisisobutyronitrile (AIBN); and/or 
 wherein the second stage (step) (b) is performed in the presence of at least one surfactant (emulsifier), especially an anionic or non-ionic surfactant, especially selected from the group consisting of anionic organic sulfates and sulfonates and non-ionic alkylene oxides, especially ethylene and/or propylene oxides, and combinations thereof, preferably selected from the group consisting of organic sulfonates, particularly dodecyl diphenyloxide disulfonates; and/or 
 wherein the second stage (step) (b) is performed under neutral or slightly alkaline conditions, preferably under at least essentially neutral conditions; and/or 
 wherein the second stage (step) (b) is performed in a water-based (waterborne) liquid milieu or carrier, especially wherein the water-based (waterborne) liquid milieu or carrier additionally comprises at least one polymerization initiator and/or at least one surfactant, preferably each as defined in any of the preceding claims, and/or optionally at least one further additive; and/or 
 wherein the second stage (step) (b) is performed at elevated temperatures and/or wherein the second stage (step) (b) is performed at a temperature in the range of from 40° C. to 200° C., especially in the range of from 50° C. to 150° C., preferably in the range of from 55° C. to 130° C., more preferably in the range of from 60° C. to 100° C.; and/or 
 wherein the second stage (step) (b) is performed at ambient pressure (1 bar or 101.325 kPa), at reduced pressure or at elevated pressure, preferably at ambient pressure (1 bar or 101.325 kPa); and/or 
 wherein the second stage (step) (b) is performed for a duration in the range of from 0.01 to 24 hours, especially in the range of from 0.1 to 12 hours, preferably in the range of from 0.5 to 6 hours, more preferably in the range of from 0.75 to 4 hours; and/or 
 wherein the second stage (step) (b) is performed until a solid content, based on the total weight of the polymerization product resulting from stage (b), of at least 25% by weight, especially of at least 30% by weight, preferably of at least 35% by weight, more preferably of at least 40% by weight, even more preferably of at least 45% by weight, most preferably of at least 50% by weight, has been reached and/or wherein the second stage (step) (b) is performed until a solid content, based on the total weight of the polymerization product resulting from stage (b), in the range of from 25 to 80% by weight, especially in the range of from 30 to 75% by weight, preferably in the range of from 35 to 70% by weight, more preferably in the range of from 40 to 65% by weight, even more preferably in the range of from 45 to 60% by weight, most preferably in the range of from 45 to 55% by weight, has been reached; and/or 
 wherein the second stage (step) (b) is performed in an at least essentially inert atmosphere, especially selected from nitrogen and noble gases, especially nitrogen; and/or 
 wherein the second stage (step) (b) is performed as an emulsion polymerization, particularly as a radical emulsion polymerization, preferably with diameter sizes of the dispersed phase from 50 nm to 1 micrometer. 
 
     
     
         15 . The method according to any of  claims 1  to  14 ,
 wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, comprises a phosphate group of the general formula (I) 
 
       
         
           
           
               
               
           
         
         in which formula (I) R 1  and R 2 , independently from each other, represent hydrogen or alkyl, preferably C 1 -C 10 -alkyl, preferably wherein both of R 1  and R 2  represent hydrogen at the same time; 
         and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, corresponds to the following general formula (II): 
       
       
         
           
           
               
               
           
         
         in which formula (II)
 R 1  and R 2 , independently from each other, represent hydrogen or alkyl, preferably C 1 -C 10 -alkyl, preferably wherein both of R 1  and R 2  represent hydrogen at the same time, 
 “Ext” represents an extender, particularly a chain extender, preferably on a polyalkylene glycol basis, more preferably on a polypropylene glycol (PPG) basis; 
 
         and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, corresponds to the following general formula (III): 
       
       
         
           
           
               
               
           
         
         
           in which formula (III) 
           R 1  and R 2 , independently from each other, represent hydrogen or alkyl, preferably C 1 -C 10 -alkyl, preferably wherein both of R 1  and R 2  represent hydrogen at the same time, 
           “Alk” represents an alkylene rest, preferably a C 2 - or C 3 -alkylene rest, more preferably a propylene rest; 
           “n” is a positive integer, preferably in the range of from 2 to 200, especially in the range of from 2 to 100, preferably in the range of from 2 to 50, more preferably in the range of from 2 to 25; 
         
         and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, corresponds to the following general formula (IV): 
       
       
         
           
           
               
               
           
         
         in which formula (IV)
 R 1  and R 2 , independently from each other, represent hydrogen or alkyl, preferably C 1 -C 10 -alkyl, preferably wherein both of R 1  and R 2  represent hydrogen at the same time, 
 “n” is a positive integer, preferably in the range of from 2 to 200, especially in the range of from 2 to 100, preferably in the range of from 2 to 50, more preferably in the range of from 2 to 25; 
 
         and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, is a mixture of monoalkylphosphate esters of polypropylene glycol monomethacrylate and dialkylphosphate esters of polypropylene glycol monomethacrylate, especially a mixture of mono(C 1 -C 10 -alkyl)phosphate esters of polypropylene glycol monomethacrylate and di(C 1 -C 10 -alkyl)phosphate esters of polypropylene glycol monomethacrylate, especially according to formula (IV); 
         and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM) is a phosphate of polypropylene glycol monomethacrylate, especially a phosphate according to formula (IV) where both of R 1  and R 2  represent hydrogen at the same time; 
         and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, is Sipomer® PAM-200 from Rhodia Solvay Group; and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, is characterized by a molecular weight, especially an average molecular weight Mw, in the range of from 250 to 3,000 g/mol, especially in the range of from 300 to 600 g/mol, preferably of about 500 g/mol; and/or 
         wherein (iii) the phosphate-group containing methacrylic monomer (PAM), which is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, is characterized by a viscosity at 23° C. of ≤4,700 cP and/or by a viscosity at 25° C. of ≤5,500 cP and/or by a glass transition temperature Tg of 0° C. and/or by a total acid number in the range of from 50 to 200 mg KOH/g. 
       
     
     
         16 . The method according to any of  claims 1  to  15 ,
 wherein (iv) the optional further monomer selected from perfluoroalkyl (meth)acrylates (PFA) is a perfluoroalkyl acrylate, preferably a perfluorooctyl acrylate (POA); and/or 
 wherein (iv) the optional further monomer selected from stearyl(meth)acrylates (SMA) is a stearyl acrylate (SA). 
 
     
     
         17 . The method according to any of  claims 1  to  16 ,
 wherein the method results in producing a coating system, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion), which comprises at least one of the following copolymers:
 (i)/(ii)/(iii)-copolymers and/or copolymers comprising moieties (i), (ii) and (iii), preferably with a (i)/(ii)/(iii)-weight ratio of (10-90)/(10-90)/(0.1-20), particularly (20-70)/(20-70)/(0.5-10), especially (40-60)/(40-60)/(1-5), however, with the proviso that the sum of the weight shares results in 100; 
 (i)/(ii)/(iii)/(iv)-copolymers and/or copolymers comprising moieties (i), (ii), (iii) and (iv), preferably with a (i)/(ii)/(iii)/(iv)-weight ratio of (20-60)/(10-50)/(0.1-20)/(10-50), particularly (25-50)/(20-40)/(0.5-10)/(20-40), especially (30-45)/(25-35)/(1-5)/(25-35), however, with the proviso that the sum of the weight shares results in 100; 
 (i)/(ii)/(iii)/(iv)-copolymers and/or copolymers comprising moieties (i), (ii), (iii) and (iv), preferably with a (i)/(ii)/(iii)/(iv)-weight ratio of (10-60)/(10-60)/(0.1-20)/(20-70), particularly (20-40)/(20-40)/(0.5-10)/(25-60), especially (25-35)/(25-35)/(1-5)/(30-50), however, with the proviso that the sum of the weight shares results in 100. 
 
 
     
     
         18 . The method according to any of  claims 1  to  17 ,
 wherein the method results in producing a coating system, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion), which comprises at least one of the following copolymers:
 MMA/BA/PAM-copolymers, preferably with a MMA/BA/PAM weight ratio of (10-90)/(10-90)/(0.1-20), particularly (20-70)/(20-70)/(0.5-10), especially (40-60)/(40-60)/(1-5), however, with the proviso that the sum of the weight shares results in 100; 
 MMA/BA/PAM/PFA-copolymers, especially MMA/BA/PAM/POA-copolymers, preferably with a MMA/BA/PAM/PFA weight ratio of (20-60)/(10-50)/(0.1-20)/(10-50), particularly (25-50)/(20-40)/(0.5-10)/(20-40), especially (30-45)/(25-35)/(1-5)/(25-35), however, with the proviso that the sum of the weight shares results in 100; 
 MMA/BA/PAM/SMA-copolymers, especially MMA/BA/PAM/SA-copolymers, preferably with a MMA/BA/PAM/SMA weight ratio of (10-60)/(10-60)/(0.1-20)/(20-70), particularly (20-40)/(20-40)/(0.5-10)/(25-60), especially (25-35)/(25-35)/(1-5)/(30-50), however, with the proviso that the sum of the weight shares results in 100. 
 
 
     
     
         19 . The method according to any of  claims 1  to  18 ,
 wherein the second stage (step) (b) is followed by a post-polymerization step; 
 especially wherein post-polymerization is performed so as to remove residual monomers; and/or 
 especially wherein post-polymerization is performed at elevated temperatures and/or wherein post-polymerization is performed at a temperature in the range of from 40° C. to 200° C., especially in the range of from 50° C. to 150° C., preferably in the range of from 55° C. to 130° C., more preferably in the range of from 60° C. to 100° C.; and/or 
 especially wherein post-polymerization is performed at ambient pressure (1 bar or 101.325 kPa), at reduced pressure or at elevated pressure, preferably at ambient pressure (1 bar or 101.325 kPa); and/or 
 especially wherein post-polymerization is performed for a duration in the range of from 0.01 to 24 hours, especially in the range of from 0.1 to 12 hours, preferably in the range of from 0.5 to 6 hours, more preferably in the range of from 0.75 to 4 hours. 
 
     
     
         20 . The method according to any of  claims 1  to  19 ,
 wherein the method is performed in the absence of organic solvents and/or in the absence of volatile organic compounds (VOCs). 
 
     
     
         21 . The method according to any of  claims 1  to  20 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i), (ii) and (iii), each as defined in any of the preceding claims, 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of a part of monomers (i) and (ii) is performed in the absence of monomer (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and the remainder of monomers (i) and (ii) are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i), (ii) and (iii). 
 
     
     
         22 . A method for producing a coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion), especially the method according to any of  claims 1  to  21 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA) and (iii) a phosphate-group containing methacrylic monomer (PAM), 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of a part of monomers (i) and (ii) is performed in the absence of monomer (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and the remainder of monomers (i) and (ii) are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA) and (iii) a phosphate-group containing methacrylic monomer (PAM), 
 wherein (iii) the phosphate-group containing methacrylic monomer (PAM) is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylate, especially as defined in any of the preceding claims. 
 
     
     
         23 . The method according to any of  claims 1  to  20 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i), (ii) and (iii) as defined in any of the preceding claims and (iv) a perfluoroalkyl (meth)acrylate (PFA), preferably a perfluorooctyl acrylate (POA), 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of a part of monomers (i) and (ii) and all of monomer (iv) is performed in the absence of monomer (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and the remainder of monomers (i) and (ii) are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i), (ii) and (iii) as defined in any of the preceding claims and (iv) perfluoroalkyl (meth)acrylate (PFA), preferably perfluorooctyl acrylate (POA). 
 
     
     
         24 . A method for producing a coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion), especially the method according to any of  claims 1  to  20  and  23 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) a perfluoroalkyl (meth)acrylate (PFA), preferably a perfluorooctyl acrylate (POA), 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of a part of monomers (i) and (ii) and all of monomer (iv) is performed in the absence of monomer (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and the remainder of monomers (i) and (ii) are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) perfluoroalkyl (meth)acrylate (PFA), preferably perfluorooctyl acrylate (POA), 
 wherein (iii) the phosphate-group containing methacrylic monomer (PAM) is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, especially as defined in any of the preceding claims. 
 
     
     
         25 . The method according to any of  claims 1  to  20 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i), (ii) and (iii) as defined in any of the preceding claims and (iv) a stearyl(meth)acrylate (SMA), preferably a stearyl acrylate, 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of all of monomer (iv) is performed in the absence of monomers (i), (ii) and (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and monomers (i) and (ii) are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i), (ii) and (iii) as defined in any of the preceding claims and (iv) a stearyl(meth)acrylate (SMA). 
 
     
     
         26 . A method for producing a coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably dispersion (emulsion), especially the method according to any of  claims 1  to  20  and  25 ,
 wherein the method comprises producing, via emulsion polymerization in a two-stage radical polymerization process, a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) a stearyl(meth)acrylate (SMA), preferably a stearyl acrylate, 
 wherein: 
 (a) in a first stage (step), an emulsion prepolymerization of all of monomer (iv) is performed in the absence of monomers (i), (ii) and (iii), so as to produce an emulsion prepolymerization product to be used as a seed in the subsequent second stage (step) (b); and then 
 (b) in a second stage (step), the emulsion prepolymerization product resulting from stage (a) and monomers (i) and (ii) are commonly polymerized together with and in the presence of monomer (iii), so as to yield a composition, preferably a dispersion (emulsion), which contains a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) a stearyl(meth)acrylate (SMA), 
 wherein (iii) the phosphate-group containing methacrylic monomer (PAM) is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, especially as defined in any of the preceding claims. 
 
     
     
         27 . A coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably in the form of a dispersion (emulsion),
 wherein the coating system is obtainable by a method as defined in any of  claims 1  to  26 .   
     
     
         28 . A coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably in the form of a dispersion (emulsion), especially the coating system according to  claim 27 ,
 wherein the coating system contains a copolymer comprising moieties of (i), (ii), (iii) and optionally (iv) as defined in any of the preceding claims.   
     
     
         29 . A coating system providing corrosion-protective properties when applied to metal surfaces, particularly in the form of a water-based (waterborne) composition, preferably in the form of a dispersion (emulsion), especially the coating system according to  claim 27  or  claim 28 ,
 wherein the coating system contains a copolymer comprising moieties of (i) methyl methacrylate (MMA), (ii) butyl acrylate (BA), (iii) a phosphate-group containing methacrylic monomer (PAM) and (iv) an optional further monomer selected from perfluoroalkyl (meth)acrylates (PFA) and stearyl(meth)acrylates (SMA), 
 wherein (iii) the phosphate-group containing methacrylic monomer (PAM) is selected from phosphates and phosphate esters of polyalkylene glycol monomethacrylates, especially as defined in any of the preceding claims. 
 
     
     
         30 . The coating system according to any of  claims 27  to  29 ,
 wherein the coating system is characterized by anyone of the features as defined in any of  claims 1  to  26 . 
 
     
     
         31 . The coating system according to any of  claims 27  to  30 ,
 wherein the coating system additionally comprises at least one surfactant, especially as defined in any of the preceding claims; and/or 
 wherein the coating system additionally comprises at least one buffer; and/or 
 wherein the coating system has a neutral or slightly alkaline pH value; and/or 
 wherein the coating system has a solid content, based on the total weight of the coating system, of at least 25% by weight, especially of at least 30% by weight, preferably of at least 35% by weight, more preferably of at least 40% by weight, even more preferably of at least 45% by weight, most preferably of at least 50% by weight; and/or 
 wherein the coating system has a solid content, based on the total weight of the coating system, in the range of from 25 to 80% by weight, especially in the range of from 30 to 75% by weight, preferably in the range of from 35 to 70% by weight, more preferably in the range of from 40 to 65% by weight, even more preferably in the range of from 45 to 60% by weight, most preferably in the range of from 45 to 55% by weight; and/or 
 wherein the coating system comprises the copolymer with absolute particle sizes, especially absolute particle diameters, in the range of from 50 nm to 5 micrometers, especially in the range of from 50 nm to 1 micrometers, preferably in the range of from 50 nm to 750 nm, more preferably in the range of from 60 nm to 500 nm, even more preferably in the range of from 60 nm to 250 nm. 
 
     
     
         32 . The coating system according to any of  claims 27  to  31 ,
 wherein the coating system comprises at least one of the following copolymers:
 (i)/(ii)/(iii)-copolymers and/or copolymers comprising moieties (i), (ii) and (iii), preferably with a (i)/(ii)/(iii)-weight ratio of (10-90)/(10-90)/(0.1-20), particularly (20-70)/(20-70)/(0.5-10), especially (40-60)/(40-60)/(1-5), however, with the proviso that the sum of the weight shares results in 100; 
 (i)/(ii)/(iii)/(iv)-copolymers and/or copolymers comprising moieties (i), (ii), (iii) and (iv), preferably with a (i)/(ii)/(iii)/(iv)-weight ratio of (20-60)/(10-50)/(0.1-20)/(10-50), particularly (25-50)/(20-40)/(0.5-10)/(20-40), especially (30-45)/(25-35)/(1-5)/(25-35), however, with the proviso that the sum of the weight shares results in 100; 
 (i)/(ii)/(iii)/(iv)-copolymers and/or copolymers comprising moieties (i), (ii), (iii) and (iv), preferably with a (i)/(ii)/(iii)/(iv)-weight ratio of (10-60)/(10-60)/(0.1-20)/(20-70), particularly (20-40)/(20-40)/(0.5-10)/(25-60), especially (25-35)/(25-35)/(1-5)/(30-50), however, with the proviso that the sum of the weight shares results in 100. 
 
 
     
     
         33 . The coating system according to any of  claims 27  to  32 ,
 wherein the coating system comprises at least one of the following copolymers:
 MMA/BA/PAM-copolymers, preferably with a MMA/BA/PAM weight ratio of (10-90)/(10-90)/(0.1-20), particularly (20-70)/(20-70)/(0.5-10), especially (40-60)/(40-60)/(1-5), however, with the proviso that the sum of the weight shares results in 100; 
 MMA/BA/PAM/PFA-copolymers, especially MMA/BA/PAM/POA-copolymers, preferably with a MMA/BA/PAM/PFA weight ratio of (20-60)/(10-50)/(0.1-20)/(10-50), particularly (25-50)/(20-40)/(0.5-10)/(20-40), especially (30-45)/(25-35)/(1-5)/(25-35), however, with the proviso that the sum of the weight shares results in 100; 
 MMA/BA/PAM/SMA-copolymers, especially MMA/BA/PAM/SA-copolymers, preferably with a MMA/BA/PAM/SMA weight ratio of (10-60)/(10-60)/(0.1-20)/(20-70), particularly (20-40)/(20-40)/(0.5-10)/(25-60), especially (25-35)/(25-35)/(1-5)/(30-50), however, with the proviso that the sum of the weight shares results in 100. 
 
 
     
     
         34 . Use of a coating system as defined in any of  claims 27  to  33  for providing corrosion protection to metal surfaces, especially metal surfaces of iron or iron-containing alloys, particularly steel, metal surfaces of aluminum and aluminum-containing alloys and metal surfaces of magnesium and magnesium-containing alloys, preferably iron or iron-containing metal surfaces, more preferably steel surfaces. 
     
     
         35 . The use according to  claim 34 ,
 wherein the coating system is applied to the metal surfaces to be provided with corrosion protection, followed by a drying step, particularly such that a polymeric film results which adheres to the metal surfaces to be protected, especially with a film thickness, based on the dry film, in the range of from 5 to 500 micrometers, preferably 10 to 250 micrometers, especially 20 to 150 micrometers, particularly 25 to 100 micrometers;   especially wherein the drying step is performed under controlled conditions, particularly at controlled temperatures and/or humidity; and/or   especially wherein the drying step is performed at temperatures in the range of from 20 to 80° C. and/or at a relative humidity in the range of from 30% to 80%; and/or   especially wherein the drying step is performed at temperatures in the range of from 20 to 30° C., preferably at about 23° C., and/or at a relative humidity in the range of from 50% to 70%, preferably at about 60%, particularly to increase phosphatization of the treated metal surfaces; and/or   especially wherein the drying step is performed at temperatures in the range of from 50 to 70° C., preferably at about 60° C., particularly to improve film formation and/or film homogeneity or coherence.   
     
     
         36 . Use of a coating system as defined in any of  claims 27  to  33  in paints, lacquers, varnishes, colors, impregnations, glazes, enamels and finishes for providing corrosion-protective properties to metal surfaces. 
     
     
         37 . Paints, lacquers, varnishes, colors, impregnations, glazes, enamels and finishes with corrosion-protective properties, comprising a coating system as defined in any of  claims 27  to  33 . 
     
     
         38 . A method for providing corrosion-protective properties to metal surfaces, wherein the method comprises a step of applying a coating system as defined in any of  claims 27  to  33  to the metal surfaces to be provided with corrosion protection. 
     
     
         39 . The method according to  claim 38 ,
 wherein the step of applying the coating system to the metal surfaces is followed by a drying step, particularly such that a polymeric film results which adheres to the metal surfaces to be protected, especially with a film thickness, based on the dry film, in the range of from 5 to 500 micrometers, preferably 10 to 250 micrometers, especially 20 to 150 micrometers, particularly 25 to 100 micrometers;   especially wherein the drying step is performed under controlled conditions, particularly at controlled temperatures and/or humidity; and/or   especially wherein the drying step is performed at temperatures in the range of from 20 to 80° C. and/or at a relative humidity in the range of from 30% to 80%; and/or   especially wherein the drying step is performed at temperatures in the range of from 20 to 30° C., preferably at about 23° C., and/or at a relative humidity in the range of from 50% to 70%, preferably at about 60%, particularly to increase phosphatization of the treated metal surfaces; and/or   especially wherein the drying step is performed at temperatures in the range of from 50 to 70° C., preferably at about 60° C., particularly to improve film formation and/or film homogeneity or coherence.   
     
     
         40 . A metal surface of an article, provided with corrosion-protective properties, wherein the metal surface has been treated with a coating system as defined in any of  claims 27  to  33 , especially by the method of  claim 38  or  claim 39 .