Methods for producing metallic materials with chemically denatured coating films.

Abstract

DEPCT6827 / 08 / 2568 The purpose of this invention is to provide a method for producing coated metallic materials. Chemical conversion coating, where a chemical conversion coating is designed to achieve a specific effect. Excellent external appearance after chemical transformation treatment, including resistance. Excellent corrosion resistance as evaluated by, for example, the exposure test or method VDA621-415. After painting, and with chemically transforming coatings, they can be used over a wide temperature range for various purposes. This is achieved through the process of producing metallic materials with chemically denatured coatings. Chemical transformations are created on or over the surface of metallic materials; methods include: Step I. The process of exposing metallic materials to a chemical transformation treatment substance involves the following: an ion source. Fluorine; source A of ions containing zirconium; source B of ions containing aluminum; and 0.0001 g / L. Up to 1,000 g / L of water-soluble or water-dispersible polymer, or salts of this C, which has structural units represented by the following formula(i) that is not less than 90% by mole; and step II of the introduction Metallic materials that have been exposed to a chemical treatment substance, come into contact with... An aqueous solution with a pH of 4 to 12 at least once; where the value is obtained by subtracting the obtained value. The following formula (2) from the values ​​obtained according to the following formula (1) will not be less than 0.2. (Ac+Bc)x(pH-2.7) to the power of 8...formula(1) (D / 0.18)raised to the power of 3 x (t / 1.5)raised to the power of 5...formula(2);

Description

Method for manufacturing metal material with chemical conversion coating

[0001] The present invention relates to a method for producing a metal material having a chemical conversion coating formed on or at the surface of a metal material.

[0002] Conventionally, metal surface treatment solutions have been developed that enable surface treatments with excellent corrosion resistance and good adhesion. For example, Patent Document 1 discloses a surface treatment composition for aluminum, an aluminum alloy, magnesium, or a magnesium alloy, which comprises: compound A containing at least one metal element selected from Hf(IV), Ti(IV), and Zr(IV); a fluorine-containing compound in an amount sufficient to cause fluorine to be present in the composition at a molar concentration at least five times the total molar concentration of the metals contained in compound A; at least one metal ion B selected from the group consisting of alkaline earth metals; at least one metal ion C selected from Al, Zn, Mg, Mn, and Cu; and nitrate ions.

[0003] WO 03 / 074761

[0004] However, in surface treatment, in addition to adhesion and corrosion resistance, appearance as a finished product is also considered important. Regarding finish quality, excessive deposition of the chemical conversion treatment agent or excessive deposition time between the contact step and the next step can result in uneven appearance and adverse effects on corrosion resistance. It is necessary to specify optimal chemical conversion treatment agent formulation conditions, as well as the deposition amount and deposition time of the chemical conversion treatment agent, to achieve sufficient performance. Furthermore, in corrosion resistance testing, exposure tests and corrosion tests that are closer to actual environmental conditions than common salt spray tests (SST) and JASO-M609 methods have recently become more important. Furthermore, in recent years, lowering the chemical conversion treatment temperature has also become more important from the perspective of reducing environmental impact. The present invention aims to provide a method for producing a chemical conversion-coated metal material with a chemical conversion coating that exhibits excellent corrosion resistance, as evaluated by post-chemical treatment appearance and post-painting exposure tests and VDA 621-415 methods, and that can be used over a wide temperature range.

[0005] As a result of extensive research to solve the above-mentioned problems, the present inventors have discovered that a chemical conversion coating that is excellent in corrosion resistance and appearance after chemical conversion treatment can be produced by a method for producing a metal material with a chemical conversion coating, the method comprising the steps of contacting a metal material with a chemical conversion treatment agent containing a fluoride ion source, a zirconium-containing ion source A, an aluminum-containing ion source B, and a specific water-soluble or water-dispersible polymer or a salt thereof C, and contacting the metal material at least once with an aqueous solution having a pH of 4 to 12, when the method is carried out under conditions that satisfy predetermined parameters, thereby completing the present invention.

[0006] The present invention includes the following: [1] A method for producing a metal material with a chemical conversion coating, in which a chemical conversion coating is formed on or at the surface of the metal material, comprising: Step I of contacting a metal material with a chemical conversion treatment agent containing a fluorine ion source, a zirconium-containing ion source A, an aluminum-containing ion source B, and 0.0001 g / L to 1.000 g / L of a water-soluble or water-dispersible polymer or salt thereof C, the polymer having 90% or more, in terms of moles, of a structural unit represented by the following formula (i): and Step II, in which the metal material that has been contacted with the chemical conversion treatment agent is contacted at least once with an aqueous solution having a pH of 4.0 or more and 12.0 or less, wherein the value obtained by subtracting the value obtained by the following formula (2) from the value obtained by the following formula (1) is 0.2 or more: (Ac + Bc) × (pH - 2.7). ８ ...Formula (1) (D / 0.18) ３ × (t / 1.5) ５ ...Equation (2) In the above equation (1), Ac is the concentration of zirconium element derived from source A in the chemical conversion treatment agent and is 2 g / L or less; Bc is the concentration of aluminum element derived from source B in the chemical conversion treatment agent and is 2 g / L or less; the ratio of Bc to Ac, Bc / Ac, is 0.03 or more and 10.0 or less; pH is the pH of the chemical conversion treatment agent and is 3.2 or more and 6.0 or less; and in the above equation (2), D is the liquid adhesion amount of the chemical conversion treatment agent that adheres to the surface of the metal material between step I and step II and is 0 L / m ２Super 0.5L / m ２ or less, where t is the time from the completion of step I to the start of step II and is 0.01 minutes or more and 3.00 minutes or less; [2] The method for producing a metal material with a chemical conversion coating according to [1], which includes, before step I, step III of contacting the metal material with an alkaline solution having a pH of 8.0 to 13.0, and step IV of contacting the metal material with an aqueous solution having a pH of 7.0 to 12.0; [3] The method for producing a metal material with a chemical conversion coating according to [1] or [2], wherein the metal material is at least one of an iron material, a zinc or zinc-based plated material, an aluminum material, an aluminum alloy material, an aluminum-based plated material, a magnesium material, and a magnesium alloy material; and the like.

[0007] According to the present invention, it is possible to provide a method for producing a metal material with a chemical conversion coating, in which a chemical conversion coating is formed on or on the surface of a metal material, which has excellent appearance after chemical conversion treatment, excellent corrosion resistance as evaluated by exposure tests after painting and the VDA 621-415 method, and which can be used over a wide temperature range.

[0008] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less. A method for producing a metal material with a chemical conversion coating according to one embodiment of the present invention will be described below.

[0009] (Chemical Conversion Treatment Agent) The chemical conversion treatment agent used in this embodiment is obtained by blending, in predetermined amounts, a fluorine ion source, a zirconium-containing ion source A, an aluminum-containing ion source B, and a water-soluble or water-dispersible polymer or salt thereof C having, in molar terms, 90% or more of a structural unit represented by formula (i). Use of this chemical conversion treatment agent makes it possible to form a chemical conversion coating on a metal material that exhibits excellent corrosion resistance and coating appearance after painting. The chemical conversion treatment agent used in this embodiment may be one in which only the fluorine ion source, source A, source B, and the predetermined polymer or salt thereof C are blended in an aqueous medium, or one in which other components are further blended.

[0010] (Fluorine Ion Source) The chemical conversion treatment agent used in this embodiment contains a fluorine ion source. The fluorine ion source is not particularly limited as long as it is a compound (hereinafter referred to as a "fluorine-containing compound") that can supply fluorine ions when incorporated into the chemical conversion treatment agent. Examples of fluorine-containing compounds 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, hydrosilicic acid, sodium fluoride, and sodium hydrogen fluoride. Compounds containing zirconium and fluorine, such as hexafluorozirconic acid, can supply both zirconium-containing ions and fluorine ions. Furthermore, only one type of fluorine-containing compound may be incorporated, or two or more types may be incorporated. There are no particular restrictions on the amount of fluorine-containing compound added, but it is preferable to add it in an amount that does not affect the formation of the chemical conversion coating, specifically, so that the fluorine ion concentration is 4 to 8 times the molar concentration of zirconium contained in the chemical conversion treatment agent plus 2 to 4 times the molar concentration of aluminum contained in the chemical conversion treatment agent. By adding the fluorine-containing compound in this range, the free fluorine ion concentration during treatment becomes appropriate, and the reaction rate between the metal material and the chemical conversion treatment agent becomes appropriate. This results in an appropriate amount of coating being formed.

[0011] (Source A) The chemical conversion treatment agent used in this embodiment contains source A. There are no particular limitations on source A, as long as it is a compound that can supply zirconium-containing ions (hereinafter referred to as "zirconium-containing ions") when incorporated into the chemical conversion treatment agent. Therefore, the chemical conversion treatment agent used in this embodiment contains zirconium-containing ions. Examples of zirconium-containing ions include metal ions of zirconium; complex ions containing zirconium; and zirconium oxide ions. Specific examples of source A for zirconium-containing ions include hexafluorozirconic acid, zirconium nitrate, zirconyl nitrate, zirconium carbonate, zirconium hydroxide, and zirconium oxide. Furthermore, if these can take the form of a salt, the salt may be used. Only one of these sources may be incorporated, or two or more may be incorporated.

[0012] The zirconium-containing ion concentration in the chemical conversion treatment agent is not particularly limited, but the zirconium element concentration Ac derived from Source A in the chemical conversion treatment agent is usually 0.02 g / L or more, preferably 0.05 g / L or more, and usually 2 g / L or less, preferably 1.5 g / L or less. When two or more sources are blended in the chemical conversion treatment agent, the concentration refers to the total concentration of zirconium element contained therein. By keeping the zirconium element concentration Ac within the above range, an effective amount of Zr can be obtained in the chemical conversion coating.

[0013] (Source B) The chemical conversion treatment agent used in this embodiment contains source B. There are no particular limitations on source B, as long as it is a compound that can supply aluminum-containing ions (hereinafter referred to as "aluminum-containing ions") when incorporated into the chemical conversion treatment agent. Therefore, the chemical conversion treatment agent used in this embodiment contains aluminum-containing ions. Examples of aluminum-containing ions include metal aluminum ions; aluminum-containing complex ions; and aluminum oxide ions. Specific examples of source B for aluminum-containing ions include, but are not limited to, aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum carbonate, and aluminum oxide. Furthermore, if these can take the form of a salt, the salt may be used. Only one of these sources may be incorporated, or two or more may be incorporated.

[0014] The aluminum-containing ion concentration in the chemical conversion treatment agent is not particularly limited, but the aluminum element concentration Bc derived from Source B in the chemical conversion treatment agent is usually 0.02 g / L or more, preferably 0.05 g / L or more, and usually 2 g / L or less, preferably 1.5 g / L or less. When two or more types of Source B are blended in the chemical conversion treatment agent, this refers to the total concentration of aluminum element derived from them. By setting the aluminum element concentration Bc within the above range, the free fluorine ion concentration in the chemical conversion treatment agent can be made appropriate.

[0015] (Ratio of Sources A and B) 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 0.03 or more and usually 10.0 or less.

[0016] (Water-soluble or water-dispersible polymer or salt thereof C) The chemical conversion treatment agent used in this embodiment contains a water-soluble or water-dispersible polymer or salt thereof C (hereinafter simply referred to as "polymer C"). There are no particular restrictions on polymer C, as long as it is a polymer having 90% or more of the structural unit represented by formula (i) above in terms of moles. Specific examples of polymer C include polydiallylamines such as diallylamine polymers; and salts of diallylamine polymers such as diallylamine hydrochloride polymers, diallylamine sulfate polymers, and diallylamine acetate polymers.

[0017] The degree of polymerization of polymer C is not particularly limited, but the weight-average molecular weight is usually 1,000 or more, preferably 5,000 or more. The weight-average molecular weight is a value measured by GPC (gel permeation column chromatography) and converted into polystyrene. The content (blending amount) of polymer C in the chemical conversion treatment agent is usually 0.0001 g / L or more, preferably 0.001 g / L or more, more preferably 0.005 g / L or more, in terms of solids mass concentration, and is usually 1.000 g / L or less, preferably (0.16 × Ac + 0.23) g / L or less. By keeping the content of polymer C within the above range, the adhesion and corrosion resistance of the chemical conversion coating are improved.

[0018] (Aqueous Medium) The chemical conversion treatment agent used in this embodiment may contain an aqueous medium. The aqueous medium is not particularly limited as long as it is water or a mixture of water and a water-miscible organic solvent (containing 50% or more by volume of water based on the volume of the aqueous medium). The water-miscible organic solvent is not particularly limited as long as it is miscible with water, and examples 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 may be mixed with water.

[0019] (Other Components) The chemical conversion treatment agent used in this embodiment may contain other additives as long as they do not impair the effects of the present invention. Specific examples include organic acids, oxidizing agents, metal ion sources other than Sources A and B, organosilane compounds, metal alkoxides, water-soluble or water-dispersible resins other than Polymer C, surfactants, pH adjusters, etc. These other components may be contained alone or in combination of two or more.

[0020] (Organic Acid) Examples of organic acids that may be contained in the chemical conversion treatment agent used in this embodiment include organic sulfonic acids, organic phosphonic acids, organic phosphoric acids, aliphatic carboxylic acids, and aromatic carboxylic acids, and specific examples include, but are not limited to, methanesulfonic acid, ethanesulfonic acid, lactic acid, oxalic acid, citric acid, etc. The organic acid may contain only one type, or may contain two or more types.

[0021] (Oxidizing Agent) Examples of oxidizing agents that can be blended into the chemical conversion treatment agent used in this embodiment include hydrogen peroxide, nitrates, nitrites, permanganates, chlorates, persulfates, nitro group-containing compounds, hypochlorous acid, organic peroxides, and bromates, with hydrogen peroxide, nitrates, and nitrites being preferred, but not limited to these. Only one type of oxidizing agent may be blended, or two or more types may be blended. Furthermore, sulfate ions may or may not be included.

[0022] (Metal Ion Sources Other Than Sources A and B) Examples of metal ion sources other than sources A and B that can be blended into the chemical conversion treatment agent used in this embodiment include, but are not limited to, compounds containing copper, iron, manganese, magnesium, nickel, cobalt, zinc, tungsten, etc. Only one type of metal ion source other than sources A and B may be blended, or two or more types may be blended.

[0023] (Organic Silane Compound) Examples of organic silane compounds that can be blended into the chemical conversion treatment agent used in this embodiment include aminosilane compounds, epoxysilane compounds, and alkoxysilane compounds. Specific examples include 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, and 3-aminopropyldimethylmeth Examples of the organic silane compound include, but are not limited to, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropylethyldiethoxysilane, 3-glycidoxypropyldiethylethoxysilane, 3-glycidoxypropyltriethoxysilane, etc. Furthermore, each organic silane compound in the chemical conversion treatment agent may be in the form of an unmodified hydrolyzate obtained by hydrolyzing the organic silane compound, a condensation polymer obtained by condensation polymerization of the hydrolyzate, a copolymer obtained by copolymerizing each hydrolyzate (such as an alternating copolymer, random copolymer, block copolymer or graft copolymer), or a mixture of multiple forms.

[0024] (Metal Alkoxides) Examples of metal alkoxides that can be blended into the chemical conversion treatment agent used in this embodiment include, but are not limited to, zirconium tetrapropoxide, zirconium tetraisopropoxide, zirconium tetra-normal propoxide, zirconium tetra-normal butoxide, titanium methoxide, titanium ethoxide, titanium tetraisopropoxide, titanium tetra-normal butoxide, titanium butoxide dimer, titanium tetra-2-ethylhexoxide, triisopropoxide vanadium(V) oxide, vanadium butoxide, triethoxyvanadium(V) oxide, aluminum isopropoxide, aluminum tert-butoxide, etc. One type of metal alkoxide may be blended alone, or two or more types may be blended. Furthermore, the metal alkoxides in the chemical conversion treatment agent may be in the form of a hydrolyzate obtained by hydrolyzing the metal alkoxides, in the form of a condensation polymer obtained by condensation polymerization of the hydrolyzate or the hydrolyzate of an organosilane compound, or in the form of a copolymer obtained by copolymerization of each hydrolyzate or the hydrolyzate of an organosilane compound (alternating copolymer, random copolymer, block copolymer, graft copolymer, etc.), or a mixture of multiple forms. The zirconium-containing metal alkoxide is also treated as source A, and the aluminum-containing metal alkoxide is also treated as source B.

[0025] (Water-soluble or water-dispersible resin other than polymer C) Examples of water-soluble or water-dispersible resins other than polymer C that can be blended into the chemical conversion treatment agent used in this embodiment include, but are not limited to, poly(meth)acrylic acid resins, urethane resins, acrylic resins, epoxy resins, phenolic resins, amine resins that do not contain a structural unit represented by formula (i), etc. One type of water-soluble or water-dispersible resin other than polymer C may be blended alone, or two or more types may be blended.

[0026] (Surfactant) Examples of surfactants that can be incorporated into the chemical conversion treatment agent used in this embodiment include ionic surfactants such as nonionic surfactants, cationic, anionic, or amphoteric surfactants. Nonionic surfactants include, but are not limited to, polyethylene glycol-type nonionic surfactants such as polyoxyethylene alkylphenyl 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. Cationic surfactants include, but are not limited to, amine salt-type cationic surfactants such as higher alkylamine salts and polyoxyethylene higher alkylamines; and quaternary ammonium salt-type cationic surfactants such as alkyltrimethylammonium salts. Anionic surfactants include, but are not limited to, higher alkyl ether sulfate ester salts to which ethylene oxide is added. The HLB value (calculated by the Griffin method) of the surfactant is not particularly limited, but is preferably from 6 to 18, and more preferably from 10 to 14. The surfactant may be blended into the chemical conversion treatment agent used in this embodiment either as a single type or as a combination of two or more types. By including the surfactant in the chemical conversion treatment agent, it becomes possible to carry out chemical conversion treatment and degreasing treatment simultaneously in one step.

[0027] (pH of Chemical Conversion Treatment Agent) The pH of the chemical conversion treatment agent used in this embodiment is typically in the acidic to neutral range, specifically within the range of 3.2 to 6.0, more preferably within the range of 3.4 to 6.0, and particularly preferably within the range of 4.1 to 5.1. Here, the pH value in this specification refers to a value measured at 40°C using a pH meter. The pH of the chemical conversion treatment agent can be adjusted using a pH adjuster such as, for example, acid components such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, and organic acids; or alkali components such as lithium hydroxide, potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, alkali metal salts, ammonia, ammonium salts, and amines, but is not limited to these components. Note that one or more pH adjusters may be used.

[0028] (Method for producing chemical conversion treatment agent) The chemical conversion treatment agent can be produced by mixing predetermined amounts of a fluoride ion source, source A, source B, and a predetermined polymer or a salt thereof C as raw materials in an aqueous medium.

[0029] (Method for forming a chemical conversion coating) The method for producing a metal material with a chemical conversion coating formed on or at the surface of a metal material according to this embodiment includes step I of contacting the surface or surface of a metal material with the chemical conversion treatment agent. This forms a chemical conversion coating on or at the surface of the metal material. Methods for contacting the metal material with the chemical conversion treatment agent include, but are not limited to, conventional contact methods, such as immersion treatment, spray treatment, pouring treatment, or combinations of these.

[0030] The contact temperature in the contact step is preferably in the range of 10°C to 60°C, and more preferably in the range of 20°C to 50°C. In this embodiment, a temperature in the range of 10°C to 25°C is defined as "low temperature," and a temperature in the range of more than 25°C to 50°C is defined as "high temperature." The contact time is preferably in the range of 30 to 300 seconds, and more preferably in the range of 60 to 180 seconds, but is not limited to these times.

[0031] The method for producing a metal material with a chemical conversion coating according to this embodiment includes, after step I of contacting a metal material with a chemical conversion treatment agent, step II of contacting the metal material contacted with the chemical conversion treatment agent with an aqueous solution having a pH of 4.0 to 12.0. The contact with the aqueous solution in contacting step II can be performed, for example, by immersion treatment, spray treatment, or the like, but is not limited thereto. The pH of the aqueous solution in contacting step II is in the range of 4.0 to 12.0, preferably in the range of 5.0 to 10.0, and particularly preferably in the range of 6.5 to 9.0. There are no particular limitations on the aqueous solution in contacting step II as long as it is within the above pH range, but examples include tap water, deionized water, and an aqueous sodium hydroxide solution. The contact in contacting step II needs to be performed at least once, but may be performed multiple times. Furthermore, a drying step of drying the surface of the metal material may be performed after contacting step II.

[0032] (Liquid Adhesion Amount D) In ​​the method for producing a metal material with a chemical conversion coating according to this embodiment, the liquid adhesion amount D is the liquid adhesion amount of the chemical conversion treatment agent that adheres to the surface of the metal material between step I and step II. When the contact method in step I is an immersion method, this refers to the adhesion amount per unit area of ​​the chemical conversion treatment agent remaining on the surface of the metal material at the time when the metal material is pulled out of the chemical conversion treatment bath and no longer comes into contact with the liquid surface. Furthermore, when the contact method in step I is a spray treatment or pouring treatment, this refers to the adhesion amount per unit area of ​​the chemical conversion treatment agent remaining on the surface of the metal material at the time when the spraying or pouring of the chemical conversion treatment agent onto the metal material is stopped. The liquid adhesion amount D is 0 L / m ２ greater than 0.5 L / m ２ or less, preferably 0.4 L / m ２ It is preferable that the content is within the following range.

[0033] (Time t from Step I to Step II) In the method for producing a metal material with a chemical conversion coating according to this embodiment, the time from the completion of Step I to the start of Step II is designated as t. If the contact method in Step I is an immersion method, the completion of Step I refers to the time when the metal material is pulled out of the chemical conversion treatment bath and no longer comes into contact with the liquid surface. If the contact method in Step I is a spray treatment or pouring treatment, the completion of Step I refers to the time when the spraying or pouring of the chemical conversion treatment agent onto the metal material stops. The start of Step II refers to the time when the metal material comes into contact with the aqueous solution in Step II. t is preferably 0.01 minutes or more and 3.00 minutes or less, more preferably 0.08 minutes or more and 2.00 minutes or less, and particularly preferably 0.1 minutes or more and 1.5 minutes or less.

[0034] (Values ​​of specific parameters) In the method for producing a metal material with a chemical conversion coating according to this embodiment, the numerical value derived from formula (1), which relates to the properties of the chemical conversion treatment agent, and the numerical value derived from formula (2), which relates to the liquid adhesion amount and residence time of the chemical conversion treatment agent, have a predetermined relationship. Specifically, the value obtained by subtracting formula (2) from formula (1) is usually 0.2 or more and 5,000 or less, preferably 0.5 or more and 2,000 or less, and more preferably 2.5 or more and 1,000 or less. When the value obtained by subtracting formula (2) from formula (1) is within the above range, a chemical conversion coating that not only has excellent corrosion resistance after painting but also excellent appearance after chemical conversion treatment can be formed on or over the surface of the metal material.

[0035] Furthermore, prior to step I of contacting with the chemical conversion treatment agent, step III of contacting with an alkaline solution having a pH of 8.0 to 13.0 and step IV of contacting with an aqueous solution having a pH of 7.0 to 12.0 may be further included. By performing steps III and IV in this manner, oil and dirt adhering to the surface of the metal material can be removed. The alkaline solution used in step III is not particularly limited as long as it is an alkaline solution having a pH of 8.0 to 13.0, and an example thereof is an alkaline solution containing a degreasing agent. Furthermore, the aqueous solution used in step IV is not particularly limited as long as it is an aqueous solution having a pH of 7.0 to 12.0, and an example thereof is an aqueous sodium hydroxide solution.

[0036] In the method for producing a metal material with a chemical conversion coating according to this embodiment, a pretreatment step may be performed in addition to steps III and IV prior to step I of contacting the metal material with a chemical conversion treatment agent. Examples of pretreatment steps include an acid pickling step, a degreasing step, an alkali cleaning step, a chromate conversion treatment step, a phosphate conversion treatment step using a phosphate such as zinc phosphate or iron phosphate, a bismuth immersion plating step, a zirconium conversion treatment step, a titanium conversion treatment step, a hafnium conversion treatment step, and a vanadium conversion treatment step. These pretreatment steps may be performed individually, or two or more steps may be combined and performed sequentially. Examples of combinations of two or more steps include a phosphate conversion treatment step and a chromate conversion treatment step, a bismuth immersion plating step, a zirconium conversion treatment step, a titanium conversion treatment step, a hafnium conversion treatment step, or a vanadium conversion treatment step. The zirconium conversion treatment step performed as the pretreatment step may use the above-mentioned chemical conversion treatment agent, or a chemical conversion treatment agent different from the above-mentioned chemical conversion treatment agent. When the above-mentioned various pretreatment steps are performed, a water washing treatment step may be performed after each pretreatment step. When a plurality of various pretreatment steps are performed, a water washing treatment step may be performed after each step or after some of the steps. Furthermore, when a water washing treatment step is performed, a drying step for drying the surface of the metal material may be performed thereafter. The order of steps III and IV and the pretreatment step is not particularly limited, and a pretreatment step may be performed before steps III and IV, or after steps III and IV. Furthermore, when two or more pretreatment steps are performed, a pretreatment step may be performed before or after steps III and IV.

[0037] Furthermore, in the method for producing a metal material with a chemical conversion coating according to this embodiment, after the contact step II, a post-treatment step such as an alkali washing step, a water washing step, a chromate conversion treatment, a zinc phosphate conversion treatment, a bismuth substitution plating step, an iron phosphate conversion treatment, a zirconium conversion treatment, a titanium conversion treatment, a hafnium conversion treatment, or a drying step may be performed. These post-treatment steps may be performed singly or in combination of two or more steps. The zirconium conversion treatment step performed as a post-treatment step may use the above-mentioned chemical conversion treatment agent, or may use a chemical conversion treatment agent different from the above-mentioned chemical conversion treatment agent. When the above-mentioned various post-treatment steps are performed, a water washing step may be performed after each of the various post-treatment steps. When multiple post-treatment steps are performed, a water washing step may be performed after each of the various post-treatment steps or after some of the steps. Furthermore, when a water washing step is performed, a drying step may be performed after the water washing step to dry the surface of the metal material.

[0038] Furthermore, a coated metal material having a chemical conversion coating and a coating film can be produced by forming a coating film on the chemical conversion coating formed by the method for producing a chemical conversion-coated metal material according to this embodiment. In this case, after the formation of the chemical conversion coating, a coating film formation process, such as a painting process and a drying process (which may include a baking process, a curing process, etc.) for drying the paint on the surface of the painted metal material to form a coating film, may be performed. A drying process may also be performed on the surface of the metal material that has undergone the water-washing treatment step II. Furthermore, one or more of the above post-treatment steps may be performed after the above step II and before the painting process. Note that, when the above various post-treatment steps are performed, a water-washing treatment step may be performed after each of the various post-treatment steps. When multiple various post-treatment steps are performed, a water-washing treatment step may be performed after each of the various post-treatment steps or after some of the steps. Furthermore, when a water-washing treatment step is performed, a drying process may be performed after the water-washing treatment step to dry the surface of the metal material.

[0039] The coating process is carried out on the surface of the metal material with the chemical conversion coating using a paint. The coating method is not particularly limited, and conventionally known methods such as rolling coating, electrodeposition coating (e.g., cationic electrodeposition coating, anionic electrodeposition coating, etc.), spray coating, hot spray coating, airless spray coating, electrostatic (powder) coating, roller coating, curtain flow coating, brush coating, bar coating, and fluidized bed coating can be applied.

[0040] Examples of the paint include known paints such as oil-based paints, cellulose derivative paints, phenolic resin paints, alkyd resin paints, aminoalkyd resin paints, urea resin paints, unsaturated resin paints, vinyl resin paints, acrylic resin paints, epoxy resin paints, polyurethane resin paints, silicone resin paints, fluororesin paints, rust-preventive paints, antifouling paints, powder paints, cationic electrodeposition paints, anionic electrodeposition paints, water-based paints, and solvent-based paints. The coating process may involve one or more coats of the same or different paints. The drying process involves drying and curing the applied paint. Examples of drying methods include natural drying, reduced-pressure drying, convection-type heat drying (e.g., natural convection-type heat drying, forced convection-type heat drying), radiation-type drying (e.g., near-infrared drying, far-infrared drying), ultraviolet curing drying, electron beam curing drying, vapor curing, and baking drying. These drying methods may be used alone or in combination of two or more.

[0041] Known methods can be used for the cationic electrodeposition coating. For example, a cationic electrodeposition coating containing an amine-added epoxy resin and a blocked polyisocyanate curing agent as a curing component is used, and the metal material with a chemical conversion coating is immersed in the coating. Cationic electrodeposition coating is performed, for example, by maintaining the temperature of the coating at a predetermined temperature, stirring the coating, and applying a voltage using a rectifier with the metal material with a chemical conversion coating as the cathode. A coating film can be formed on the chemical conversion coating by rinsing and baking the metal material that has been subjected to cationic electrodeposition coating in this manner. Baking is performed for a certain period of time within a predetermined temperature range. For example, baking can be performed at 170°C for 20 minutes. When using a cationic electrodeposition coating method using a cationic electrodeposition coating, it is preferable to perform the water rinsing process using water with a sodium ion concentration of less than 500 ppm by mass before the coating process to prevent aggregation of the coating due to sodium ions.

[0042] Known methods can be used for applying powder coatings, such as spray coating, electrostatic powder coating, and fluidized bed dipping. Examples of powder coatings include those containing a polyester resin and, as a curing agent, a blocked isocyanate curing agent, a β-hydroxyalkylamide curing agent (see, for example, JP 2011-88083 A), or triglycidyl isocyanurate. Baking is performed for a certain period of time within a predetermined temperature range. For example, baking is performed at 130°C to 250°C for 20 minutes.

[0043] Known methods can be used for applying the solvent-based paint, such as spray painting, electrostatic painting, and bar coating. Examples of solvent-based paints include those containing a resin such as melamine resin, acrylic resin, urethane resin, or polyester resin, and an organic solvent such as thinner. Baking is performed for a certain period of time within a predetermined temperature range. For example, baking at 130°C for 20 minutes can be used.

[0044] Drying methods for curing the applied paint include, for example, natural drying, reduced pressure drying, convection heat drying (e.g., natural convection heat drying, forced convection heat drying), radiation drying (e.g., near-infrared drying, far-infrared drying), ultraviolet curing drying, electron beam curing drying, vapor curing, etc. These drying methods may be used alone or in combination of two or more.

[0045] The coating film obtained by the coating process may be a single layer or multiple layers. In the case of multiple layers, the paints for forming the various coating films, the coating method using the paints, the method for drying the coated metal material, etc. may be the same or different.

[0046] Examples of metal materials include iron (e.g., cold-rolled steel plate, hot-rolled steel plate, high-tensile steel plate, tool steel, alloy tool steel, spheroidized graphite cast iron, gray cast iron, etc.); plated materials, for example, zinc and zinc-based plated materials (e.g., electrogalvanized, hot-dip galvanized, hot-dip zinc-aluminum plated, hot-dip zinc-aluminum-magnesium plated, alloyed hot-dip galvanized, electrogalvanized, etc.); aluminum and aluminum alloy materials (e.g., 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 castings, aluminum alloy castings, die-cast materials, etc.); aluminum-based plated materials; and magnesium and magnesium alloy materials (e.g., AZ91, AZ61AZ31, etc.).

[0047] The chemical conversion coating formed by the method for producing a metal material with a chemical conversion coating according to this embodiment has a mass of zirconium contained in the chemical conversion coating of 5 mg / m per unit area. ２ It is preferable that the concentration is 10 mg / m or more. ２ More preferably, it is 20 mg / m or more. ２ The upper limit is not particularly limited, but is preferably 800 mg / m ２It is preferable that the mass of zirconium in the chemical conversion coating is not more than 100%. The mass of zirconium in the chemical conversion coating can be measured, for example, by using an X-ray fluorescence analyzer.

[0048] The metal material having a chemical conversion coating produced by the method for producing a metal material with a chemical conversion coating according to this embodiment may have one or more of the above-mentioned various coatings (e.g., a chromate chemical conversion coating, a phosphate conversion coating, a bismuth displacement plating coating, etc.) on or under the chemical conversion coating obtained by contacting the metal material with the chemical conversion treatment agent according to this embodiment.

[0049] A coated metal material having a chemical conversion coating and a coating film can be produced by applying a paint to the surface of a metal material having a chemical conversion coating according to this embodiment to form a coating film. The coated metal material may have a coating film on the surface of the metal material having a chemical conversion coating according to this embodiment, or may have a coating film on the surface of one or more of the above-mentioned various coatings (e.g., chromate conversion coating, phosphate conversion coating, bismuth substitution plating coating, vanadium conversion coating, etc.) further formed on the chemical conversion coating. The coating film may consist of one layer or two or more layers. The thickness of the coating film is not particularly limited and is set appropriately depending on the intended use of the coated metal material.

[0050] The effects of the present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. <Metallic Materials> As metallic materials, cold-rolled mild steel sheet (SPCC: thickness 0.8 mm) conforming to JIS G3141:2011, galvannealed steel sheet (GA: thickness 0.8 mm) conforming to JIS G3302:2012, aluminum alloy sheet (A6061: thickness 0.8 mm) conforming to JIS H4000:2014, hot-dip galvanized steel sheet (SGCC: thickness 0.8 mm) conforming to JIS G3302:2012, magnesium alloy sheet (MP-AZ31B: thickness 0.8 mm) conforming to JIS H4201:2018, and hot-dip zinc-aluminum-magnesium coating (ZM40 / 40: thickness 0.8 mm) were each cut to a size of 70 mm long x 150 mm wide and used.

[0051] <Components used in preparing the chemical conversion treatment agent> The following raw materials were used in preparing the chemical conversion treatment agent. (Source A) A1: hexafluorozirconic acid A2: zirconium nitrate A3: zirconium hydroxide (Source B) B1: aluminum nitrate B2: aluminum hydroxide (Polymer C) C1: diallylamine polymer (PAS-21; Nittobo Medical Co., Ltd., formula (i) content: 100%) C2: diallylamine hydrochloride polymer (PAS-21CL; Nittobo Medical Co., Ltd., formula (i) content: 100%) C3: allylamine hydrochloride-diallylamine hydrochloride polymer (PAA-D11-HCL; Nittobo Medical Co., Ltd., formula (i) content: 50%) Note that hydrofluoric acid was used as a source of fluoride ions.

[0052] In addition, the following raw materials were used as other additives. (Organic acids D) D1: methanesulfonic acid D2: ethanesulfonic acid D3: succinic acid D4: citric acid (Oxidizing agents E) E1: nitric acid (Metals F other than sources A and B) F1: ferric sulfate F2: iron (III) nitrate F3: copper nitrate (Organic silane compounds G) 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: isocyanatepropyltriethoxysilane (Metal alkoxides H) H1: titanium methoxide H2: Vanadium propoxide H3: Zirconium tetra-normal propoxide H4: Aluminum isopropoxide H5: Vinyltrimethoxysilane (Other components) I1: Hydroxylamine sulfate I2: Ascorbic acid

[0053] <Preparation of Chemical Conversion Treatment Agents> As shown in Tables 1 to 5, the chemical conversion treatment agents of Examples 1 to 59 and Comparative Examples 1 to 27 were prepared by blending the respective components in predetermined amounts and then adjusting the pH to a predetermined value with sodium hydroxide.

[0054] <Production of Metallic Materials with Chemical Conversion Coatings> As shown in Tables 1 to 5, various metallic materials were treated to produce metallic materials with chemical conversion coatings. That is, various metallic materials were dissolved in water to a concentration of degreasing agent (FC-E2093; Nihon Parkerizing Co., Ltd.; Agent A 13 g / L, Agent B 11 g / L), and then degreased with sodium hydroxide or CO. ２ The metal material was immersed in an alkaline solution (adjusted to a predetermined pH with a gas) at 43°C for 120 seconds (Step III). After contact with the alkaline solution, an aqueous solution adjusted to a predetermined pH with sodium hydroxide was sprayed at 25°C for 30 seconds (Step IV). When two types of aqueous solutions were used in Step IV, each aqueous solution was sprayed for 30 seconds at 25°C. After spraying, the metal material was placed flat on a plane, and various chemical conversion treatment agents (chemical conversion treatment agents of Examples 1 to 59 and Comparative Examples 1 to 27) were applied to the evaluation surface at a liquid deposition amount D (L / m) shown in Tables 1 to 5. ２ ) for 120 seconds (Step I). The temperature of the treatment solution during spraying was set at 15°C as the low temperature and 38°C as the high temperature. After spraying the chemical conversion treatment solution, it was left to stand for the predetermined time t minutes shown in Tables 1 to 5 (Steps I to II). Thereafter, the surface of the metal material having the obtained chemical conversion coating was washed with tap water of pH 6 and deionized water of pH 7, in that order (Step II). After washing with water, the test piece for appearance evaluation was dried at 40°C for 10 minutes. The test piece for corrosion resistance after painting was not dried and was subjected to painting as described below.

[0055]

[0056]

[0057]

[0058]

[0059]

[0060] <Production of Metallic Materials with Coating Films> Metallic materials with coating films were produced by painting on the chemical conversion coatings formed on the surfaces of various metallic materials and then baking them. Details of the painting method and baking conditions are shown below.

[0061] (Cationic Electrodeposition Coating) A metal material having a chemical conversion coating was used as the cathode, and a cationic electrodeposition paint (KG-400; manufactured by Kansai Paint Co., Ltd.) was used to electrolyze the metal material to form a coating film. The electrolysis was performed at an applied voltage of 180 V and a temperature of 30.0±0.5°C. The amount of electricity was adjusted so that the coating film thickness was 15.0±1.0 μm. After cationic electrodeposition, the surface of the coating film was washed with deionized water and baked at 170°C for 20 minutes to produce a metal material (each test piece) having a coating film.

[0062] <Chemical Appearance> The appearance of the coating of the test pieces having the chemical conversion coatings obtained in each Example and Comparative Example was visually evaluated. <Evaluation Criteria> A: No unevenness on the flat surface and edges when the test piece was viewed from the front, and no unevenness on the flat surface and edges when the test piece was tilted 20° from the front B: No unevenness on the flat surface and edges when the test piece was viewed from the front, and unevenness on the flat surface and edges when the test piece was tilted 20° from the front C: No unevenness on the flat surface and unevenness on the edges when the test piece was viewed from the front, and unevenness on the flat surface and edges when the test piece was tilted 20° from the front D: Unevenness on the flat surface and edges when the test piece was viewed from the front, and unevenness on the flat surface and edges when the test piece was tilted 20° from the front

[0063] <Corrosion Resistance Test (Exposure Test)> Using a utility knife, an X-shaped scratch (cross cut) was made on the coating surface of various test pieces having a coating, reaching down to the metal substrate, and the test pieces were exposed near the sea off Okinawa. After two years, the coating blister width (maximum blister width on one side) from the scratch (cross cut) on the test piece was measured. Corrosion resistance was evaluated according to the following evaluation criteria. <Evaluation Criteria - Cross Cut> A: Blister width on one side is less than 5.0 mm B: Blister width on one side is 5.0 mm or more and less than 10.0 mm C: Blister width on one side is 10.0 mm or more and less than 15.0 mm D: Blister width on one side is 15.0 mm or more

[0064] <Corrosion Resistance Test (VDA Method)> Using a utility knife, a single scratch was made in the center of the coating surface of each test piece having a coating, reaching down to the metal substrate, and a corrosion cycle test was performed for six cycles according to VDA test 621-415 and DIN EN ISO 20567-1 (1982 version; method C). The blister width (maximum blister width on one side) from the scratch (cut) on the test piece was measured. Corrosion resistance was evaluated according to the following evaluation criteria. <Evaluation Criteria—Cut Part> A: Blister width on one side less than 5.0 mm B: Blister width on one side 5.0 mm or more but less than 10.0 mm C: Blister width on one side 10.0 mm or more but less than 15.0 mm D: Blister width on one side 15.0 mm or more The results of each evaluation test are shown in Tables 6 to 8. In all evaluations, a grade of B or higher was considered a pass level.

[0065]

[0066]

[0067]

[0068] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the invention.

Claims

DEPCT6827 / 08 / 25681. Methods for the production of metallic materials with chemical conversion coatings; chemical conversion coatings which are formed on or over the surface of metallic materials; methods which consist of: Step I of exposing the metallic material to a chemical conversion treatment agent containing: a source of fluorine ions; a source A of zirconium ions; a source B of aluminum ions; and 0.0001 g / L to 1.000 g / L of a water-soluble or water-dispersible polymer. Or a salt of this C, whose structural unit is represented by the following formula(i):(chemical formula)...formula(i) not less than 90% by mole; and step II of bringing the metallic material which has been exposed to the chemical transformation agent, to an aqueous solution with a pH of 4.0 to 12.0 at least once; where the value obtained by subtracting the value obtained by the following formula(2) from the value obtained by the following formula(1):(Ac+Bc)x(pH-2.7)to the power of 8...formula(1)(D / 0.18)to the power of 3x(t / 1.5)to the power of 5...formula(2) shall not be less than 0.2, where in formula(1), Ac is the concentration of zirconium obtained from source A in the chemical transformation agent, and not more than 2 g / L; Bc is the concentration of aluminum obtained from source B in the chemical transformation agent, and 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 transformation agent, and is 3.2 to 6.0; where in formula(2), D is the amount of liquid adhesion of the chemical transformation agent to the surface of the material being treated.

1. The metallization rate between steps I and II shall be no less than 0 L / m² and no more than 0.5 L / m²; and t is the time from the completion of step I until the start of step II, and shall be between 0.01 minutes and 3.00 minutes.

2. The method of producing a chemically transforming coating on the metallized material according to claim 1 shall consist of: step III of exposing the metallized material to an alkaline liquid with a pH of 8.0 to 13.0; and step IV of exposing the metallized material to an aqueous solution with a pH of 7.0 to 12.0; before step I. 3.Methods of producing metallic materials with chemically transformed coatings according to claim 1 or 2 where the metallic material is at least one or more types of iron, zinc or zinc-based plated material, aluminum, aluminum alloy, aluminum-based plated material, magnesium, and magnesium alloy;