Method for producing metal material with chemical conversion coating film

Abstract

An object of the present invention is to provide a method of producing a metallic material having a chemical conversion coating, which chemical conversion coating is formed to achieve excellent external appearance after chemical conversion treatment, as well as excellent corrosion resistance as evaluated by, for example, an exposure test or the VDA621-415 method after painting, and which chemical conversion coating can be used in a wide temperature range. The object is achieved by a method of producing a metallic material having a chemical conversion coating, the chemical conversion coating being formed on or over a surface of the metallic material, the method including: Step I of bringing the metallic material into contact with a chemical conversion treatment agent containing: a source of fluorine ions; a source A of ions containing zirconium; a source B of ions containing aluminum; and 0.0001 g / L to 1.000 g / L of a water-soluble or water-dispersible polymer, or a salt thereof C, containing structural units represented by the following Formula (i) at not less than 90% by mole; and Step II of bringing the metallic material that has been brought into contact with the chemical conversion treatment agent, into contact with an aqueous solution with a pH of 4.0 to 12.0 at least once; wherein the value obtained by subtracting the value obtained according to the following Formula (2) from the value obtained according to the following Formula (1) is not less than 0.2. Ac+Bc×pH−2.78 D / 0.183×t / 1.55

Description

TECHNICAL FIELD

[0001] The present invention relates to a method of producing a metallic material having a chemical conversion coating, the chemical conversion coating being formed on or over a surface of the metallic material.BACKGROUND ART

[0002] Conventionally, treatment liquids for treatment of metal surfaces, which treatment liquids enable application of surface treatment that achieves excellent corrosion resistance and favorable adhesiveness, have been developed. For example, Patent Document 1 discloses a surface treatment composition for aluminum, an aluminum alloy, magnesium, or a magnesium alloy, the composition comprising: Compound A, which contains at least one metallic element selected from Hf (IV), Ti (IV), and Zr (IV); a fluorine-containing compound in an amount sufficient to allow the presence, in the composition, of fluorine at least five times the total molar concentration of metals contained in the Compound A; at least one metal ion B, selected from the group of alkaline earth metals; at least one metal ion C, selected from Al, Zn, Mg, Mn, and Cu; and a nitrate ion.PRIOR ART DOCUMENT[Patent Document]

[0003] [Patent Document 1] WO 03 / 074761SUMMARY OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0004] However, for the surface treatment, not only adhesiveness and corrosion resistance, but also external appearance as a finishing performance have been considered to be important. Regarding the finishing performance, unevenness of the external appearance and deterioration of the corrosion resistance performance occur in cases where the amount of adhering liquid of the chemical conversion treatment agent is too much, or where the adhesion time is too long, during the period of transition from the contact step of the chemical conversion treatment agent to the subsequent step. For the production of a sufficient performance, it is necessary to specify the optimal conditions for the inclusion of the chemical conversion treatment agent, the amount of adhering liquid of the chemical conversion treatment agent, and the adhesion time. Further, in recent years, exposure tests and corrosion tests have been considered to be important in corrosion resistance tests since exposure tests and corrosion tests provide environmental conditions closer to the actual conditions compared to salt spray tests (SST) and the JASO-M609 method, which have been commonly employed. Further, in recent years, from the viewpoint of reducing the environmental load, lowering of the chemical conversion treatment temperature has also been considered to be important.

[0005] An object of the present invention is to provide a method of producing a metallic material having a chemical conversion coating, which chemical conversion coating is formed to achieve excellent external appearance after chemical conversion treatment, as well as excellent corrosion resistance as evaluated by, for example, an exposure test or the VDA621-415 method after painting, and which chemical conversion coating can be used in a wide temperature range.MEANS FOR SOLVING THE PROBLEMS

[0006] In order to solve the above problem, the present inventors intensively studied to discover that a chemical conversion coating having excellent corrosion resistance and excellent external appearance after chemical conversion treatment can be produced by a method of producing a metallic material having a chemical conversion coating when the method is carried out under conditions satisfying predetermined parameters, the method comprising: a step of bringing a metallic material into contact with a chemical conversion treatment agent containing: a source of fluorine ions; a source A of ions containing zirconium; a source B of ions containing aluminum; and a specific water-soluble or water-dispersible polymer, or a salt thereof C; and a step of bringing the metallic material into contact with an aqueous solution with a pH of 4 to 12 at least once, thereby completing the present invention.

[0007] The present invention includes, for example, the following: [1] a method of producing a metallic material having a chemical conversion coating, the chemical conversion coating being formed on or over a surface of the metallic material, the method comprising: Step I of bringing the metallic material into contact with a chemical conversion treatment agent containing: a source of fluorine ions; a source A of ions containing zirconium; a source B of ions containing aluminum; and 0.0001 g / L to 1.000 g / L of a water-soluble or water-dispersible polymer, or a salt thereof C, containing structural units represented by the following Formula (i): at not less than 90% by mole; and Step II of bringing the metallic material that has been brought into contact with the chemical conversion treatment agent, into contact with an aqueous solution with a pH of 4.0 to 12.0 at least once; wherein the value obtained by subtracting the value obtained according to the following Formula (2) from the value obtained according to the following Formula (1): Ac + Bc × pH − 2.7 8 D / 0.18 3 × t / 1.5 5 is not less than 0.2, wherein in the Formula (1), Ac is the concentration of zirconium element derived from the Source A in the chemical conversion treatment agent, and is not more than 2 g / L; Bc is the concentration of aluminum element derived from the Source B in the chemical conversion treatment agent, and is not more than 2 g / L; the ratio of Bc to Ac, Bc / Ac, is 0.03 to 10.0; and pH is the pH of the chemical conversion treatment agent, and is 3.2 to 6.0; wherein in the Formula (2), D is the amount of adhering liquid of the chemical conversion treatment agent on a surface of the metallic material between Step I and Step II, and is more than 0 L / m 2< and not more than 0.5 L / m 2< ; and t is a time from completion of the Step I to beginning of Step II, and is 0.01 minutes to 3.00 minutes; [2] the method of producing a metallic material having a chemical conversion coating according to [1], comprising: Step III of bringing the metallic material into contact with an alkaline liquid with a pH of 8.0 to 13.0; and Step IV of bringing the metallic material into contact with an aqueous solution with a pH of 7.0 to 12.0; before the Step I; and [3] the method of producing a metallic material having a chemical conversion coating according to [1] or [2], wherein the metallic material is at least one or more of iron materials, zinc or zinc-based plating materials, aluminum materials, aluminum alloy materials, aluminum-based plating materials, magnesium materials, and magnesium alloy materials. EFFECT OF THE INVENTION

[0008] The present invention can provide a method of producing a metallic material having a chemical conversion coating, the chemical conversion coating being formed on or over a surface of the metallic material, which metallic material has excellent external appearance after chemical conversion treatment, as well as excellent corrosion resistance as evaluated by, for example, an exposure test or the VDA621-415 method after painting, and which metallic material can be used in a wide temperature range.MODE FOR CARRYING OUT THE INVENTION

[0009] In the present description, a numerical value range expressed using "to" means the range that includes the numerical values described before and after the "to" as the lower limit value and the upper limit value, respectively, and "A to B" means a value that is not less than A and not more than B.

[0010] A method of producing a metallic material having a chemical conversion film according to one embodiment of the present invention is described below.(Chemical Conversion Treatment Agent)

[0011] The chemical conversion treatment agent used in the present embodiment comprises predetermined amounts of: a source of fluorine ions; a source A of ions containing zirconium; a source B of ions containing aluminum; and a water-soluble or water-dispersible polymer, or a salt thereof C, containing structural units represented by Formula (i) at not less than 90% by mole; in an aqueous medium. By using this chemical conversion treatment agent, a chemical conversion coating that achieves excellent corrosion resistance after painting, and excellent external appearance of the coating, can be formed for metallic materials. In the chemical conversion treatment agent used in the present embodiment, only the source of fluorine ions; Source A; Source B; and the predetermined polymer or a salt thereof C; may be contained in the aqueous medium, or other components may also be contained therein.(Source of Fluorine Ions)

[0012] The chemical conversion treatment agent used in the present embodiment contains a source of fluorine ions. The source of fluorine ions is not limited as long as it is a compound capable of supplying fluorine ions (hereinafter referred to as "fluorine-containing compound") when the source is included in the chemical conversion treatment agent. Examples of the fluorine-containing compound include, but are not limited to, hexafluorozirconic acid, hexafluorotitanic acid, hexafluorohafnic acid, hydrofluoric acid, ammonium fluoride, ammonium hydrogen fluoride, germanium fluoride, potassium fluoride, potassium hydrogen fluoride, iron fluoride, hydrofluosilicic acid, sodium fluoride, and sodium hydrogen fluoride. Compounds containing zirconium and fluorine, such as hexafluorozirconic acid, are capable of supplying both zirconium-containing ions and fluorine ions. Only one fluorine-containing compound may be included, or two or more fluorine-containing compounds may be included. The amount of the fluorine-containing compound included is not limited as long as the formation of the chemical conversion coating is not affected. Specifically, the fluorine-containing compound is preferably included such that the fluorine ion concentration is the sum of four to eight times the molar concentration of zirconium element contained in the chemical conversion treatment agent and two to four times the molar concentration of aluminum element contained in the chemical conversion treatment agent. By including the fluorine-containing compound within such a range, the free fluorine ion concentration during the treatment becomes appropriate, so that a favorable reaction rate can be achieved between the metallic material and the chemical conversion treatment agent. Thus, a favorable amount of coating can be formed.(Source A)

[0013] Source A is included in the chemical conversion treatment agent used in the present embodiment. Source A is not limited as long as it is a compound capable of supplying ions containing zirconium (hereinafter referred to as "zirconium-containing ions") when the source is included in the chemical conversion treatment agent. Therefore, the chemical conversion treatment agent used in the present embodiment contains zirconium-containing ions. Examples of the zirconium-containing ions include metal ions of zirconium; complex ions containing zirconium; and oxide ions of zirconium.

[0014] Specific examples of the source A of zirconium-containing ions, include hexafluorozirconic acid, zirconium nitrate, zirconyl nitrate, zirconium carbonate, zirconium hydroxide, and zirconium oxide. In cases where these may be in the forms of salts, such salts may be used. Only one of these sources may be included, or two or more of these sources may be included.

[0015] The concentration of zirconium-containing ions in the chemical conversion treatment agent is not limited, but the zirconium element concentration Ac derived from Source A, in the chemical conversion treatment agent is usually not less than 0.02 g / L, preferably not less than 0.05 g / L, and is usually not more than 2 g / L, preferably not more than 1.5g / L. In cases where two or more kinds of sources are included in the chemical conversion treatment agent, Ac means the total concentration of zirconium element contained in these.

[0016] In cases where the zirconium element concentration Ac is within the range described above, an effective amount of Zr can be achieved in the chemical conversion coating.(Source B)

[0017] Source B is included in the chemical conversion treatment agent used in the present embodiment contains Source B. Source B is not limited as long as it is a compound capable of supplying ions containing aluminum (hereinafter referred to as "aluminum-containing ions") when the source is included in the chemical conversion treatment agent. Therefore, the chemical conversion treatment agent used in the present embodiment contains aluminum-containing ions. Examples of the aluminum-containing ions include metal ions of aluminum; complex ions containing aluminum; and oxide ions of aluminum. Specific examples of the source B of aluminum-containing ions, include, but are not limited to, aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum carbonate, and aluminum oxide. In cases where these may be in the forms of salts, such salts may be used. Only one of these sources may be included, or two or more of these sources may be included.

[0018] The concentration of aluminum-containing ions in the chemical conversion treatment agent is not limited, but the aluminum element concentration Bc derived from Source B, in the chemical conversion treatment agent is usually not less than 0.02 g / L, preferably not less than 0.05 g / L, and is usually not more than 2 g / L, preferably not more than 1.5g / L. In cases where two or more kinds of Sources B are included in the chemical conversion treatment agent, Bc means the total concentration of aluminum element derived from these.

[0019] In cases where the aluminum element concentration Bc is within the range described above, an appropriate free fluorine ion concentration can be achieved in the chemical conversion treatment agent.(Ratio between Sources A and B)

[0020] The ratio (Bc / Ac) of the aluminum element concentration Bc derived from Source B, to the zirconium element concentration Ac derived from Source A, in the chemical conversion treatment agent is usually not less than 0.03, and usually not more than 10.0.(Water-Soluble or Water-Dispersible Polymer, or Salt Thereof C)

[0021] The chemical conversion treatment agent used in the present embodiment comprises a water-soluble or water-dispersible polymer, or a salt thereof C (hereinafter simply referred to as "Polymer C"). Polymer C is not limited as long as it is a polymer containing structural units represented by the Formula (i) at not less than 90% by mole. Specific examples of Polymer C include polydiallylamines including: diallylamine polymers; and salts of diallylamine polymers such as diallylamine hydrochloride polymers, diallylamine sulfate polymers, and diallylamine acetate polymers.

[0022] The degree of polymerization of Polymer C is not limited. Its weight average molecular weight is usually not less than 1000, preferably not less than 5000. The weight average molecular weight is a value measured by GPC (gel permeation column chromatography) and calculated in terms of polystyrene.

[0023] The content (amount included) of Polymer C in the chemical conversion treatment agent is usually not less than 0.0001 g / L, preferably not less than 0.001 g / L, more preferably not less than 0.005 g / L, and is usually not more than 1.000 g / L, preferably not more than (0.16 × Ac + 0.23) g / L, in terms of the mass concentration of solids. In cases where the content of Polymer C is within the range described above, adhesiveness and corrosion resistance of the chemical conversion coating can be improved.(Aqueous Medium)

[0024] The chemical conversion treatment agent used in the present embodiment may contain an aqueous medium. The aqueous medium is not limited as long as it is water, or a mixture of water and a water-miscible organic solvent (in which water is contained at not less than 50% by volume with respect to the volume of the aqueous medium). The water-miscible organic solvent is not limited as long as the solvent is miscible with water, and examples of the solvent include ketone-based solvents such as acetone and methyl ethyl ketone; amide-based solvents such as N,N'-dimethylformamide and dimethylacetamide; alcohol-based solvents such as methanol, ethanol, and isopropanol; ether-based solvents such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether; and pyrrolidone-based solvents such as 1-methyl-2-pyrrolidone and 1-ethyl-2-pyrrolidone. One of these water-miscible organic solvents may be mixed with water, or two or more of these may be mixed with water.(Other Components)

[0025] In the chemical conversion treatment agent used in the present embodiment, other additives may be included within ranges in which the effect of the present invention is not inhibited. Specific examples of the other components include organic acids; oxidizing agents; sources of metal ions other than Sources A and B; organosilane compounds; metal alkoxides; water-soluble resins or water-dispersible resins other than Polymer C; surfactants; and pH-adjusting agents. Only one of these other components may be included, or two or more of these other components may be included.(Organic Acids)

[0026] Examples of organic acids that may be included in the chemical conversion treatment agent used in the present embodiment include, but are not limited to, organic sulfonic acids, organic phosphonic acids, organic phosphoric acids, aliphatic carboxylic acids, and aromatic carboxylic acids; specifically, methanesulfonic acid, ethanesulfonic acid, lactic acid, oxalic acid, and citric acid. Only one organic acid may be included, or two or more organic acids may be included.(Oxidizing Agents)

[0027] Examples of oxidizing agents that may be included in the chemical conversion treatment agent used in the present embodiment include, but are not limited to, hydrogen peroxide, nitrate, nitrite, permanganate, chlorate, persulfate, nitro-containing compounds, hypochlorous acid, organic peroxide, and bromate; preferably, hydrogen peroxide, nitrate, and nitrite. Only one oxidizing agent may be included, or two or more oxidizing agents may be included. Sulfate ions may or may not be included.(Sources of Metal Ions Other Than Sources A and B)

[0028] Examples of sources of metal ions other than Sources A and B that may be included in the chemical conversion treatment agent used in the present embodiment include, but are not limited to, compounds containing copper, iron, manganese, magnesium, nickel, cobalt, zinc, tungsten, or the like. Only one source, or two or more sources, of metal ions other than Sources A and B may be included.(Organosilane Compounds)

[0029] Examples of organosilane compounds that may be included in the chemical conversion treatment agent used in the present embodiment include aminosilane compounds, epoxysilane compounds, and alkoxysilane compounds. Specific examples of the organosilane compounds include, but are not limited to, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyldimethylmethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyldiethylethoxysilane, N-2-(aminoethyl)-3-aminopropylethyldiethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyldiethylethoxysilane, 3-aminopropylethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropylethyldiethoxysilane, 3-glycidoxypropyldiethylethoxysilane, and 3-glycidoxypropyltriethoxysilane. In the chemical conversion treatment agent, each organosilane compound may be present as it is, may be in the form of a hydrolysate derived by hydrolysis of an organosilane compound, may be in the form of a polycondensate derived by polycondensation of the hydrolysate, may be in the form of a copolymer (alternating copolymer, random copolymer, block copolymer, graft copolymer, or the like) derived by copolymerization of individual hydrolysates, or may be a mixture of a plurality of forms.(Metal Alkoxides)

[0030] Examples of metal alkoxides that may be included in the chemical conversion treatment agent used in the present embodiment include, but are not limited to, zirconium tetrapropoxide, zirconium tetraisopropoxide, zirconium tetra-normal propoxide, zirconium tetranormal butoxide, titanium methoxide, titanium ethoxide, titanium tetraisopropoxide, titanium tetranormal butoxide, titanium butoxide dimer, titanium tetra-2-ethylhexoxide, triisopropoxide vanadium (v) oxide, vanadium butoxide, triethoxyvanadium (v) oxide, aluminum isopropoxide, and aluminum-tert-butoxide. One metal alkoxide may be included alone, or two or more metal alkoxides may be included. In the chemical conversion treatment agent, each metal alkoxide may be present as it is, may be in the form of a hydrolysate derived by hydrolysis of a metal alkoxide, may be in the form of a polycondensate derived by polycondensation of the hydrolysate, or of an organosilane compound hydrolysate, may be in the form of a copolymer (alternating copolymer, random copolymer, block copolymer, graft copolymer, or the like) derived by copolymerization of individual hydrolysates or organosilane compound hydrolysates, or may be a mixture of a plurality of forms.

[0031] Metal alkoxides containing zirconium are also regarded as Source A, and metal alkoxides containing aluminum are also regarded as Source B.(Water-Soluble Resins or Water-Dispersible Resins Other Than Polymer C)

[0032] Examples of water-soluble resins or water-dispersible resins other than Polymer C that may be included in the chemical conversion treatment agent used in the present embodiment include, but are not limited to, poly(meth)acrylate resins, urethane resins, acrylic resins, epoxy resins, and phenol resins; and amine resins not containing a structural unit represented by Formula (i). One water-soluble resin or water-dispersible resin other than Polymer C may be included alone, or two or more water-soluble resins and / or water-dispersible resins other than Polymer C may be included.(Surfactants)

[0033] Examples of surfactants that may be included in the chemical conversion treatment agent used in the present embodiment include nonionic surfactants; and ionic surfactants such as cationic, anionic, or amphoteric surfactants. Examples of the nonionic surfactants include, but are not limited to, polyethylene glycol-type nonionic surfactants such as polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene-polyoxypropylene-block polymers; polyhydric alcohol-type nonionic surfactants such as sorbitan fatty acid esters; and amide-type nonionic surfactants such as fatty acid alkylolamides. Examples of the cationic surfactants include, but are not limited to, amine salt-type cationic surfactants such as higher alkyl amine salts and polyoxyethylene higher alkyl amines; and quaternary ammonium salt-type cationic surfactants such as alkyltrimethylammonium salts. Examples of the anionic surfactants include, but are not limited to, higher alkyl ether sulfuric acid ester salts to which ethylene oxide is added. The HLB value (as calculated by the Griffin's method) of the surfactants is not limited, and is preferably 6 to 18, more preferably 10 to 14. One of the surfactants may be included alone, or two or more of the above surfactants may be included, in the chemical conversion treatment agent used in the present embodiment. By including the above surfactant(s) in the chemical conversion treatment agent, chemical conversion treatment and degreasing treatment can be carried out at the same time in one step.(pH of Chemical Conversion Treatment Agent)

[0034] The pH of the chemical conversion treatment agent used in the present embodiment is usually in the acidic to neutral range. Specifically, the pH is within the range of 3.2 to 6.0, more preferably within the range of 3.4 to 6.0, especially preferably within the range of 4.1 to 5.1. The pH value in the present description means a value measured at 40°C using a pH meter.

[0035] The pH of the chemical conversion treatment agent may be adjusted using a pH-adjusting agent, such as an acid component, for example, hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, or an organic acid; or an alkaline component, for example, lithium hydroxide, potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, an alkali metal salt, ammonia, an ammonium salt, or an amine. However, the components are not limited to these. One pH-adjusting agent, or two or more pH-adjusting agents may be used.(Method of Producing Chemical Conversion Treatment Agent)

[0036] The chemical conversion treatment agent can be produced by including predetermined amounts of a source of fluorine ions, Source A, Source B, and a predetermined polymer or a salt thereof C, as raw materials in an aqueous medium.(Method of Forming Chemical Conversion Coating)

[0037] The method of producing a metallic material having a chemical conversion coating, the chemical conversion coating being formed on or over a surface of the metallic material, according to the present embodiment comprises Step I of bringing the chemical conversion treatment agent into contact on or over the surface of the metallic material. By this, a chemical conversion coating is formed on or over the surface of the metallic material. Examples of the method of bringing the chemical conversion treatment agent into contact with the metallic material include, but are not limited to, conventional contact methods such as treatment methods including the immersion treatment method, the spray treatment method, the pouring treatment method, and combinations thereof.

[0038] The contact temperature in the above contact step is preferably within the range of 10°C to 60°C, more preferably within the range of 20°C to 50°C. In the present embodiment, the range of from 10°C to 25°C is regarded as "low temperature", and the range of from more than 25°C to not more than 50°C is regarded as "high temperature". The contact time is preferably within the range of 30 seconds to 300 seconds, more preferably within the range of 60 seconds to 180 seconds. However, the contact time is not limited thereto.

[0039] In the method of producing a metallic material having a chemical conversion coating according to the present embodiment, Step I of bringing the metallic material into contact with a chemical conversion treatment agent is followed by Step II of bringing the metallic material that has been brought into contact with the chemical conversion treatment agent, into contact with an aqueous solution with a pH of 4.0 to 12.0. The contact with the aqueous solution according to the contact step II is carried out, for example, by the immersion treatment method, the spray treatment method, or the like. However, the contact method is not limited to these. The pH of the aqueous solution according to the contact step II is within the range of 4.0 to 12.0, preferably within the range of 5.0 to 10.0, especially preferably within the range of 6.5 to 9.0. The aqueous solution according to the contact step II is not limited as long as the pH is within the range described above. Examples of the aqueous solution include tap water, deionized water, and aqueous sodium hydroxide solutions. The contact according to the contact step II may be carried out at least once, and may be carried out a plurality of times. After performing the contact step II, a drying step of drying the surface of the metallic material may be carried out.(Amount of Adhering Liquid D)

[0040] In the method of producing a metallic material having a chemical conversion coating according to the present embodiment, the amount of adhering liquid D, is the amount of adhering liquid of the chemical conversion treatment agent on the surface of the metallic material between Step I and Step II. In cases where the contact method in Step I is the immersion method, D refers to the amount of the chemical conversion treatment agent remaining on the surface of the metallic material per unit area at the time point when the metallic material is pulled out of the chemical conversion treatment bath and no longer in contact with the liquid surface. In cases where the contact method in Step I is spray treatment or pouring treatment, D refers to the amount of the chemical conversion treatment agent remaining on the surface of the metallic material per unit area at the time point when spraying or pouring of the chemical conversion treatment agent onto the metallic material is stopped. The amount of adhering liquid D is preferably within the range of from more than 0 L / m 2< to not more than 0.5 L / m 2< , preferably not more than 0.4 L / m 2< .(Time t from Step I to Step II, t)

[0041] In the method of producing a metallic material having a chemical conversion coating according to the present embodiment, t is defined as the time from the completion of Step I to the beginning of Step II. In cases where the contact method in Step I is the immersion method, the time point of the completion of Step I refers to the time point when the metallic material is pulled out of the chemical conversion treatment bath and no longer in contact with the liquid surface. In cases where the contact method in Step I is spray treatment or pouring treatment, the time point of the completion of Step I refers to the time point when spraying or pouring of the chemical conversion treatment agent onto the metallic material is stopped. The time point of the beginning of Step II refers to the time point when the metallic material is brought into contact with the aqueous solution in Step II. t is preferably 0.01 minutes to 3.00 minutes, more preferably 0.08 minutes to 2.00 minutes, especially preferably 0.1 minutes to 1.5 minutes.(Values of Specific Parameters)

[0042] In the method of producing a metallic material having a chemical conversion coating according to the present embodiment, there is a predetermined relationship between the value derived from Formula (1), which is related to properties of the chemical conversion treatment agent, and the value derived from Formula (2), which is related to the amount of adhering liquid of the chemical conversion treatment agent and the retention time of the liquid. The value obtained by subtracting Formula (2) from Formula (1) is usually 0.2 to 5000, preferably 0.5 to 2000, more preferably 2.5 to 1000. In cases where the value obtained by subtracting Formula (2) from Formula (1) is within the range described above, it is possible to form, on or over a surface of the metallic material, a chemical conversion coating having not only excellent corrosion resistance after painting, but also excellent external appearance after chemical conversion treatment.

[0043] Further, Step III of bringing the metallic material into contact with an alkaline liquid with a pH of 8.0 to 13.0 and Step IV of bringing the metallic material into contact with an aqueous solution with a pH of 7.0 to 12.0 may be included before Step I of bringing the metallic material into contact with the chemical conversion treatment agent. By carrying out Step III and Step IV in this manner, oil and dirt adhering to the surface of the metallic material can be removed. The alkaline liquid according to Step III is not limited as long as it is an alkaline liquid with a pH of 8.0 to 13.0. Examples of the alkaline liquid include alkaline liquids containing a degreasing agent. The aqueous solution according to Step IV is not limited as long as it is an aqueous solution with a pH of 7.0 to 12.0. Examples of the aqueous solution include aqueous sodium hydroxide solutions.

[0044] In the method of producing a metallic material having a chemical conversion coating according to the present embodiment, a pretreatment step may be carried out in addition to Step III and Step IV, before Step I of bringing the metallic material into contact with the chemical conversion treatment agent. Examples of the pretreatment step include an acid pickling step; a degreasing step; an alkali washing step; a chromate chemical conversion treatment step; a phosphate chemical conversion treatment step using a phosphate such as zinc phosphate or iron phosphate; a bismuth displacement plating step; a zirconium chemical conversion treatment step; a titanium chemical conversion treatment step; a hafnium chemical conversion treatment step; and a vanadium chemical conversion treatment step. One of these pretreatment steps may be carried out, or two or more of these pretreatment steps may be carried out sequentially in combination. Examples of the combination of two or more steps include the combination of a phosphate chemical conversion treatment step with a chromate chemical conversion treatment step, a bismuth displacement plating step, a zirconium chemical conversion treatment step, a titanium chemical conversion treatment step, a hafnium chemical conversion treatment step, or a vanadium chemical conversion treatment step. In the zirconium chemical conversion treatment step performed as a pretreatment step, the above chemical conversion treatment agent may be used, or a chemical conversion treatment agent different from the above chemical conversion treatment agent may be used. In cases where a pretreatment step(s) described above is / are carried out, water washing treatment step may be carried out after the pretreatment step(s). In cases where a plurality of pretreatment steps is carried out, a water washing treatment step may be carried out after each step, or after some of the steps. In cases where the water washing treatment step is carried out, a drying step of drying the surface of the metallic material may be carried out thereafter.

[0045] The order of Step III, Step IV, and the pretreatment step is not limited. The pretreatment step may be carried out before Step III and Step IV, or the pretreatment step may be carried out after Step III and Step IV In cases where two or more pretreatment steps are carried out, the pretreatment steps may be carried out before and after Step III and Step IV

[0046] In the method of producing a metallic material having a chemical conversion coating according to the present embodiment, the contact step II may be followed by a post-treatment step such as an alkali washing step, a water washing step, chromate chemical conversion treatment, a zinc phosphate chemical conversion treatment step, a bismuth displacement plating step, an iron phosphate chemical conversion treatment step, a zirconium chemical conversion treatment step, a titanium chemical conversion treatment step, a hafnium chemical conversion treatment step, or a drying step. One of these post-treatment steps may be carried out alone, or two or more of these steps may be carried out sequentially in combination. In the zirconium chemical conversion treatment step performed as a post-treatment step, the above chemical conversion treatment agent may be used, or a chemical conversion treatment agent different from the above chemical conversion treatment agent may be used. In cases where a post-treatment step(s) described above is / are carried out, water washing treatment step may be carried out after the post-treatment step(s). In cases where a plurality of post-treatment steps is carried out, a water washing treatment step may be carried out after each step, or after some of the steps. In cases where the water washing treatment step is carried out, a drying step of drying the surface of the metallic material may be carried out thereafter.

[0047] Further, a paint may be formed on a chemical conversion coating formed by the method of producing a metallic material having a chemical conversion coating according to the present embodiment, to produce a painted metallic material having the chemical conversion coating and the paint. In this case, the formation of the chemical conversion coating may be followed by a paint formation treatment for forming the paint, such as a painting step and a drying step of drying the paint material on the surface of the metallic material after the painting (which may include, for example, a baking step and a curing step).

[0048] After performing the water washing treatment step II, a drying step of drying the surface of the metallic material may be carried out. Further, one of, or two or more of the above post-treatment steps may be carried out after the Step II but before the painting step. In cases where a post-treatment step(s) described above is / are carried out, a water washing treatment step(s) may be carried out after the post-treatment step(s). In cases where a plurality of post-treatment steps is carried out, a water washing treatment step may be carried out after each step, or after some of the steps. In cases where the water washing treatment step is carried out, a drying step of drying the surface of the metallic material may be carried out thereafter.

[0049] The painting step is carried out using a paint material, for the surface of the metallic material having the chemical conversion coating. The painting method is not limited, and a conventionally known method may be applied. Examples of the conventionally known method include roll painting, electrodeposition painting (for example, cationic electrodeposition painting and anionic electrodeposition painting), spray painting, hot spray painting, airless spray painting, electrostatic (powder) painting, roller coating, curtain flow coating, brush painting, bar coating, and the fluidized bed painting method.

[0050] Examples of the paint material include known paint materials such as oilbased paint materials, cellulose derivative paint materials, phenol resin paint materials, alkyd resin paint materials, amino-alkyd resin paint materials, urea resin paint materials, unsaturated resin paint materials, vinyl resin paint materials, acrylic resin paint materials, epoxy resin paint materials, polyurethane resin paint materials, silicone resin paint materials, fluorine resin paint materials, anticorrosive paints, antifouling paint materials, powder paint materials, cationic electrodeposition paint materials, anionic electrodeposition paint materials, aqueous paint materials, and solvent paint materials. In the painting step, a single paint may be formed, or two or more paints may be formed using the same or different paint material(s). The drying step is a step of drying the paint material after painting, to cure the paint material. Examples of the drying method include air drying, vacuum drying, convective heat drying (for example, natural convective heat drying or forced convective heat drying), radiation drying (for example, near-infrared drying or far-infrared drying), ultraviolet dry-curing, electron beam dry-curing, Vapocure, and bake drying. One of these drying methods may be carried out, or two or more of these drying methods may be carried out in combination.

[0051] As the cationic electrodeposition paint, a known method may be applied. Examples of the method include a method using a cationic electrodeposition paint material containing: an amine-added epoxy resin as a paint material; and a blocked polyisocyanate curing agent as a curing component; wherein the metallic material having the chemical conversion coating is immersed in this paint material. The cationic electrodeposition paint is carried out, for example, by application of a voltage using a rectifier, and using the metallic material having the chemical conversion coating as a cathode, while the paint material is kept at a predetermined temperature under stirring. For the metallic material that has been subjected to the cationic electrodeposition paint in this manner, water washing and baking may be carried out to form a paint on the chemical conversion coating. The baking is carried out within a predetermined temperature range for a predetermined length of time. For example, in one mode, the baking is carried out at 170°C for 20 minutes. In cases where the cationic electrodeposition painting method using a cationic electrodeposition paint material is applied, the water washing treatment step is preferably carried out before the painting step, using water whose sodium ion concentration is less than 500 ppm by mass, in order to prevent aggregation of the paint material due to sodium ions.

[0052] In cases where a powder paint material is used, a known method may be applied as a painting method such as spray painting, electrostatic powder painting, or the fluidized bed painting method. Examples of the powder paint material include a material containing: a polyester resin; and a blocked polyisocyanate curing agent, a β-hydroxyalkylamide curing agent (see, for example, JP 2011-88083 A), or triglycidyl isocyanurate as a curing agent. The baking is carried out within a predetermined temperature range for a predetermined length of time. For example, in one mode, the baking is carried out at 130°C to 250°C for 20 minutes.

[0053] In cases where the solvent paint material is used, a known method may be applied as a painting method such as spray painting, electrostatic painting, or bar coating. Examples of the solvent paint material include a material containing: a resin such as a melamine resin, an acrylic resin, a urethane resin, or a polyester resin; and an organic solvent such as a thinner. The baking is carried out within a predetermined temperature range for a predetermined length of time. For example, in one mode, the baking is carried out at 130°C for 20 minutes.

[0054] Examples of the drying method for curing the paint material after painting include air drying, vacuum drying, convective heat drying (for example, natural convective heat drying or forced convective heat drying), radiation drying (for example, near-infrared drying or far-infrared drying), ultraviolet dry-curing, electron beam dry-curing, and Vapocure. One of these drying methods may be carried out, or two or more of these drying methods may be carried out in combination.

[0055] The paint obtained by the painting step may have a single layer or a plurality of layers. In cases where the paint has a plurality of layers, the paint materials for forming the paints, the painting methods using the paint materials, the drying methods for the metallic material after painting, and the like may each be the same or different.

[0056] Examples of the metallic material include iron (for example, cold-rolled steel sheets, hot-rolled steel sheets, high-tensile steel sheets, tool steels, alloy tool steels, spheroidal graphite cast irons, and gray cast iron); plated materials such as zinc and zinc-based plated materials (for example, zinc electroplated materials, zinc hot-dipped materials, zinc-aluminum-based hot-dipped materials, zinc-aluminum-magnesium-based hot-dipped materials, alloyed zinc hot-dipped materials, and zinc-based electroplated materials); aluminum and aluminum alloy materials (for example, 1000 series aluminum alloy materials, 2000 series aluminum alloy materials, 3000 series aluminum alloy materials, 4000 series aluminum alloy materials, 5000 series aluminum alloy materials, 6000 series aluminum alloy materials, 7000 series aluminum alloy materials, 8000 series aluminum alloy materials, aluminum casts, aluminum alloy casts, and die-cast materials); aluminum-based plated materials; and magnesium and magnesium alloy materials (for example, AZ91 and AZ61AZ31).

[0057] In the chemical conversion coating formed by the method of producing a metallic material having a chemical conversion coating according to the present embodiment, the mass of zirconium contained is preferably not less than 5 mg / m 2< , more preferably not less than 10 mg / m 2< , still more preferably not less than 20 mg / m 2< per unit area. Although there is no upper limit value, the mass is preferably not more than 800 mg / m 2< . The mass of zirconium in this chemical conversion coating may be measured, for example, using an X-ray fluorescence analyzer.

[0058] The metallic material having the chemical conversion coating produced by the method of producing a metallic material having a chemical conversion coating according to the present embodiment may have one of, or two or more of the above-described various coatings (for example, a chromate chemical conversion coating, a phosphate chemical conversion coating, or a bismuth displacement plating coating) on either side of the chemical conversion coating obtained by bringing the chemical conversion treatment agent according to the present embodiment into contact.

[0059] By painting the surface of a metallic material having a chemical conversion coating according to the present embodiment using a paint material, a paint can be formed to produce a painted metallic material having the chemical conversion coating and the paint. The painted metallic material may have the paint on the surface of the metallic material having the chemical conversion coating according to the present embodiment, or may have the paint on the surface of one or more of the above-described various coatings (for example, a chromate chemical conversion coating, a phosphate chemical conversion coating, a bismuth displacement plating coating, or a vanadium chemical conversion coating) additionally formed on the chemical conversion coating. The paint may have a single layer, or may have two or more layers. The thickness of the paint is not limited, and is set appropriately according to the use of the painted metallic material.EXAMPLES

[0060] The effects of the present invention are described below in detail by way of Examples. However, the present invention is not limited by the following Examples.<Metallic Materials>

[0061] As metallic materials, a cold-rolled mild steel sheet compatible with the JIS G3141:2011 standard (SPCC: thickness, 0.8 mm), an alloyed zinc hot-dipped steel sheet compatible with the JIS G3302:2012 standard (GA: thickness, 0.8 mm), an aluminum alloy sheet compatible with the JIS H4000:2014 standard (A6061: thickness, 0.8 mm), a zinc hot-dipped steel sheet compatible with the JIS G3302:2012 standard (SGCC: thickness, 0.8 mm), a magnesium alloy sheet compatible with the JIS H4201:2018 standard (MP-AZ31B: thickness, 0.8 mm), and a zinc-aluminum-magnesium-based hot-dipped material (ZM40 / 40: thickness, 0.8 mm) were used after cutting each of these to a size of 70 mm (length) × 150 mm (width).<Components Used in Preparation of Chemical Conversion Treatment Agents>

[0062] Chemical conversion treatment agents were prepared using the following raw materials.(Source A)

[0063] A1: Hexafluorozirconic acid A2: Zirconium nitrate A3: Zirconium hydroxide (Source B)

[0064] B1: Aluminum nitrate B2: Aluminum hydroxide (Polymer C)

[0065] C1: Diallylamine polymer (PAS-21; Nittobo Medical Co., Ltd.; content ratio of Formula (i), 100%) C2: Diallylamine hydrochloride polymer (PAS-21CL; Nittobo Medical Co., Ltd.; content ratio of Formula (i), 100%) C3: Allylamine hydrochloride-diallylamine hydrochloride polymer (PAA-D11-HCL; Nittobo Medical Co., Ltd.; content ratio of Formula (i), 50%)

[0066] Hydrofluoric acid was used as a source of fluorine ions.

[0067] In addition, the following raw materials were used as other additives.(Organic Acid D)

[0068] D1: Methanesulfonic acid D2: Ethanesulfonic acid D3: Succinic acid D4: Citric acid (Oxidizing Agent E)

[0069] E1: Nitric acid(Metals Other Than Sources A and B (Metal F))

[0070] F1: Ferric sulfate F2: Iron (III) nitrate F3: Copper nitrate (Organosilane Compound G)

[0071] G1: 3-Aminopropyldimethylmethoxysilane G2: 3-Aminopropylmethyldimethoxysilane G3: 3-Aminopropyldiethylethoxysilane G4: 3-Aminopropylethyldiethoxysilane G5: 3-Aminopropyltriethoxysilane G6: 3-Aminopropyltrimethoxysilane G7: 3-Glycidoxypropyltrimethoxysilane G8: Ethyltrimethoxysilane G9: Ureidopropyltriethoxysilane G10: Isocyanate propyltriethoxysilane (Metal Alkoxide H)

[0072] H1: Titanium methoxide H2: Vanadium propoxide H3: Zirconium tetranormal propoxide H4: Aluminum isopropoxide H5: Vinyltrimethoxysilane (Other Components)

[0073] I1: Hydroxylamine sulfate I2: Ascorbic acid <Preparation of Chemical Conversion Treatment Agents>

[0074] As shown in Tables 1 to 5, predetermined amounts of the components were added, and then the pH was adjusted to a predetermined value with sodium hydroxide, to prepare chemical conversion treatment agents of Examples 1 to 59 and Comparative Examples 1 to 27.<Production of Metallic Materials Having Chemical Conversion Coating>

[0075] As shown in Tables 1 to 5, metallic materials were treated to produce metallic materials having a chemical conversion coating. Specifically, each metallic material was immersed in a degreasing agent (FC-E2093; Nihon Parkerizing Co., Ltd.; an alkaline liquid prepared by dissolving Agent A and Agent B at concentrations of 13 g / L and 11 g / L, respectively, and adjusting the pH to a predetermined value with sodium hydroxide or CO 2 gas) at 43°C for 120 seconds (Step III). After the contact with the alkaline liquid, an aqueous solution whose pH had been adjusted to a predetermined value with sodium hydroxide was sprayed at 25°C for 30 seconds (Step IV). When two kinds of aqueous solutions were used in Step IV, each aqueous solution was sprayed at 25°C for 30 seconds. The metallic material after the spraying was placed flat on a flat surface, and various chemical conversion treatment agents (chemical conversion treatment agents of Examples 1 to 59 and Comparative Examples 1 to 27) were sprayed on the evaluation surface for 120 seconds such that the amounts (L / m 2< ) of adhering liquid, D, in Tables 1 to 5 were achieved (Step I). The temperature of the treatment liquid at the time of spraying was set to 15°C in the case of low temperature, and 38°C in the case of high temperature. After the spraying of the chemical conversion treatment liquid, the metallic material was left to stand for the predetermined time (t minutes) shown in Tables 1 to 5 (between Steps I and II). Thereafter, the surface of the resulting metallic material having the chemical conversion coating was washed with tap water at pH 6, and then with deionized water at pH 7 (Step II).

[0076] After the washing with water, a test piece for evaluation of the external appearance was dried at 40°C for 10 minutes. A test piece for the corrosion resistance after painting was not dried before it was subjected to the paint described below. <Production of Metallic Materials Having Paint>

[0077] The chemical conversion coating formed on the surface of each metallic material was painted, and then baking was carried out to prepare a metallic material having a paint.

[0078] Details of the painting method, and the baking conditions are described below.(Cationic Electrodeposition Paint)

[0079] A paint was formed by electrolysis using, as a cathode, a metallic material having each type of chemical conversion coating, and using a cationic electrodeposition paint material (KG-400; manufactured by Kansai Paint Co., Ltd.). The electrolysis was carried out at an applied voltage of 180 V and a temperature of 30.0 ± 0.5°C. In the electrolysis, the quantity of electricity was adjusted to achieve a paint thickness of 15.0 ± 1.0 µm. After the cationic electrodeposition, the surface of the paint was washed with deionized water, and baking was carried out at 170°C for 20 minutes, to prepare a metallic material (each test piece) having the paint.<External Appearance of Chemical Conversion Coating>

[0080] For the test piece having a chemical conversion coating obtained in each of Examples and Comparative Examples, the external appearance of the coating was rated by visual observation.<Evaluation Criteria>

[0081] A: Unevenness was found neither on the planar section nor the edges when the test piece was viewed from the front side. Unevenness was found neither on the planar section nor the edges when the test piece was viewed at an angle of 20° with respect to the front side. B: Unevenness was found neither on the planar section nor the edges when the test piece was viewed from the front side. Unevenness was found on the planar section and the edges when the test piece was viewed at an angle of 20° with respect to the front side. C: Unevenness was not found on the planar section, but was found on the edges when the test piece was viewed from the front side. Unevenness was found on the planar section and the edges when the test piece was viewed at an angle of 20° with respect to the front side. D: Unevenness was found on the planar section and the edges when the test piece was viewed from the front side. Unevenness was found on the planar section and the edges when the test piece was viewed at an angle of 20° with respect to the front side. <Corrosion Resistance Test (Exposure Test)>

[0082] Using a cutter knife, an X-shaped scratch (cross-cut) was made on the painted surface of each test piece having a paint, such that the scratch reached the metal substrate. The test piece was then placed near the sea in Okinawa to perform the exposure for 2 years. Thereafter, the blister width (the maximum blister width on one side) of the paint from the scratched portion (cross-cut portion) on the test piece was measured. Corrosion resistance was evaluated according to the following evaluation criteria.<Evaluation Criteria - Cross-Cut Portion>

[0083] A: The blister width on one side was less than 5.0 mm. B: The blister width on one side was not less than 5.0 mm, and less than 10.0 mm. C: The blister width on one side was not less than 10.0 mm, and less than 15.0 mm. D: The blister width on one side was not less than 15.0 mm. <Corrosion Resistance Test (VDA Method)>

[0084] Using a cutter knife, a single scratch was made at the center of the painted surface of each test piece having a paint, such that the scratch reached the metal substrate. Thereafter, six cycles of a corrosion cycle test were carried out using the VDA test according to 621-415 and DIN EN ISO 20567-1 (1982 version; method C). The blister width (the maximum blister width on one side) of the paint from the scratched portion (cut portion) on the test piece was measured. Corrosion resistance was evaluated according to the following evaluation criteria.<Evaluation Criteria - Cut Portion>

[0085] A: The blister width on one side was less than 5.0 mm. B: The blister width on one side was not less than 5.0 mm, and less than 10.0 mm. C: The blister width on one side was not less than 10.0 mm, and less than 15.0 mm. D: The blister width on one side was not less than 15.0 mm.

[0086] The results of the evaluation tests are shown in Tables 6 to 8. In all evaluations, test pieces with rank A or B were judged as acceptable.

[0087] Although the present invention is described in detail with reference to concrete examples, it is evident to those skilled in the art that various changes and modifications may be made without departing from the spirit and the scope of the present invention.

Claims

1. A method of producing a metallic material having a chemical conversion coating, the chemical conversion coating being formed on or over a surface of the metallic material, the method comprising: Step I of bringing the metallic material into contact with a chemical conversion treatment agent containing: a source of fluorine ions; a source A of ions containing zirconium; a source B of ions containing aluminum; and 0.0001 g / L to 1.000 g / L of a water-soluble or water-dispersible polymer, or a salt thereof C, containing structural units represented by the following Formula (i): at not less than 90% by mole; and Step II of bringing the metallic material that has been brought into contact with the chemical conversion treatment agent, into contact with an aqueous solution with a pH of 4.0 to 12.0 at least once; wherein the value obtained by subtracting the value obtained according to the following Formula (2) from the value obtained according to the following Formula (1): Ac + Bc × pH − 2.7 8 D / 0.18 3 × t / 1.5 5 is not less than 0.2, wherein in the Formula (1), Ac is the concentration of zirconium element derived from the Source A in the chemical conversion treatment agent, and is not more than 2 g / L; Bc is the concentration of aluminum element derived from the Source B in the chemical conversion treatment agent, and is not more than 2 g / L; the ratio of Bc to Ac, Bc / Ac, is 0.03 to 10.0; and pH is the pH of the chemical conversion treatment agent, and is 3.2 to 6.0; wherein in the Formula (2), D is the amount of adhering liquid of the chemical conversion treatment agent on a surface of the metallic material between Step I and Step II, and is more than 0 L / m2 and not more than 0.5 L / m2; and t is a time from completion of the Step I to beginning of Step II, and is 0.01 minutes to 3.00 minutes.

2. The method of producing a metallic material having a chemical conversion coating according to claim 1, comprising: Step III of bringing the metallic material into contact with an alkaline liquid with a pH of 8.0 to 13.0; and Step IV of bringing the metallic material into contact with an aqueous solution with a pH of 7.0 to 12.0; before the Step I.

3. The method of producing a metallic material having a chemical conversion coating according to claim 1 or 2, wherein the metallic material is at least one or more of iron materials, zinc or zinc-based plating materials, aluminum materials, aluminum alloy materials, aluminum-based plating materials, magnesium materials, and magnesium alloy materials.

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