Water-based surface treatment agents and surface-treated metals

Abstract

To provide an aqueous surface treatment agent which can improve electrolyte resistance when metal is laminated.SOLUTION: An aqueous surface treatment agent that is used in metal surface treatment contains an ethylene-vinyl alcohol copolymer (A1), a carboxyl group-containing polymer (A2) having a structural unit derived from a radical-polymerizable carboxyl group-containing monomer, and a trivalent chromium compound (B), wherein a mass ratio (M / A1+A2) of a mass (M) of a trivalent chromium contained in the trivalent chromium compound (B) with respect to the total amount of the ethylene-vinyl alcohol copolymer (A1) and the carboxyl group-containing polymer (A2) having the structural unit derived from the radical-polymerizable carboxyl group-containing monomer is 0.05 or more and 2.90 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous surface treatment agent and a surface-treated metal. [Background technology]

[0002] Conventionally, in order to protect metal and to provide a design, metal is laminated by adhering a laminate film to the metal.

[0003] To maintain the aesthetic appearance and corrosion resistance of the laminated metal, it is important to improve the adhesion of the laminate film, and for example, a method of treating aluminum or an aluminum alloy with a surface treatment agent is known (see Patent Document 1). Here, the surface treatment agent contains a water-soluble zirconium compound, a water-soluble or water-dispersible acrylic resin, and a water-soluble or water-dispersible thermosetting crosslinking agent.

[0004] On the other hand, laminate films are excellent in processability, corrosion resistance, barrier properties, etc., and are also less likely to generate volatile organic compounds when laminated to metals. Therefore, laminated metals are used, for example, as exterior materials for batteries. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-265821 Summary of the Invention [Problem to be solved by the invention]

[0006] When a laminated metal is used as an exterior material for a battery, it is desirable to improve the resistance to an electrolyte.

[0007] An object of the present invention is to provide an aqueous surface treatment agent that can improve resistance to an electrolyte when laminating metals. [Means for solving the problem]

[0008] (1) The present invention relates to an aqueous surface treatment agent used for the surface treatment of metals, comprising an ethylene-vinyl alcohol copolymer (A1), a carboxyl group-containing polymer (A2) having structural units derived from a radically polymerizable carboxyl group-containing monomer, and a trivalent chromium compound (B), wherein the mass ratio (M / A1+A2) of the mass of trivalent chromium (M) contained in the trivalent chromium compound (B) to the total amount of the ethylene-vinyl alcohol copolymer (A1) and the carboxyl group-containing polymer (A2) having structural units derived from a radically polymerizable carboxyl group-containing monomer is 0.05 or more and 2.90 or less.

[0009] (2) The aqueous surface treatment agent according to (1), further comprising a hydroxyl group-crosslinking compound (C1) capable of reacting with the hydroxyl groups of the ethylene-vinyl alcohol copolymer (A1) to form crosslinks.

[0010] (3) The aqueous surface treatment agent according to (2), wherein the hydroxyl group-crosslinking compound (C1) is one or more compounds selected from the group consisting of organic titanium compounds, organic zirconium compounds, melamine resins, and blocked isocyanates.

[0011] (4) The aqueous surface treatment agent according to any one of (1) to (3), further comprising a carboxyl group-crosslinking compound (C2) capable of reacting with a carboxyl group of the carboxyl group-containing polymer (A2) having a structural unit derived from the radically polymerizable carboxyl group-containing monomer to form a crosslink.

[0012] (5) The aqueous surface treatment agent according to (4), wherein the carboxyl group-crosslinking compound (C2) is one or more compounds selected from the group consisting of oxazoline compounds, silane coupling agents, epoxy compounds, and carbodiimide compounds.

[0013] (6) The aqueous surface treatment agent according to any one of (1) to (5), further comprising an organic chelating agent (D).

[0014] (7) The aqueous surface treatment agent according to (6), wherein the organic chelating agent (D) has one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, a phosphonic acid group, a phosphoric acid group, and an amino group.

[0015] (8) A surface-treated metal having a coating formed by treating the metal with the aqueous surface treatment agent according to any one of (1) to (7).

[0016] (9) The surface-treated metal according to (8), wherein the metal is aluminum or an aluminum alloy, iron or an iron alloy, or copper or a copper alloy.

[0017] (10) The surface-treated metal according to (8) or (9), wherein the metal is plated.

[0018] (11) The surface-treated metal according to any one of (8) to (10), wherein the metal having the coating is laminated.

[0019] (12) The surface-treated metal according to (11), which is an exterior material for a battery. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an aqueous surface treatment agent that can improve the electrolyte resistance when laminated on a metal. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described.

[0022] [Water-based surface treatment agent] The aqueous surface treatment agent of the present embodiment is used for treating the surface of a metal.

[0023] The metal is not particularly limited, but examples thereof include iron, zinc, aluminum, copper, nickel, etc., and two or more types may be used in combination. That is, the metal may be an alloy. The alloy components may include, for example, carbon, nitrogen, oxygen, phosphorus, sulfur, silicon, manganese, chromium, titanium, molybdenum, etc. Among these, aluminum or aluminum alloys, iron or iron alloys, or copper or copper alloys are preferred from the viewpoints of workability and adhesion, and aluminum or aluminum alloys are more preferred. Examples of aluminum alloys include Al-Cu alloys, Al-Mn alloys, Al-Si alloys, Al-Mg alloys, Al-Mg-Si alloys, Al-Zn-Mg alloys, and aluminum die-cast (ADC material). When the surface-treated metal of this embodiment described below is used as a battery exterior material, it is preferable to use 8079 material or the like as the aluminum alloy. Examples of aluminum alloys that can be used for other applications include 3004, 3104, and 3005 materials for beverage and food can bodies, 5052 and 5182 materials for beverage and food can lids, 1050, 1100, and 1200 materials for dry battery containers, and 8021 materials for electrodes. Examples of iron alloys include cold-rolled steel sheets such as SPCC, SPCD, and SPCE, and stainless steel (SUS). Examples of SUS include austenitic stainless steels such as SUS304, SUS301, and SUS316, ferritic stainless steels such as SUS430, and martensitic stainless steels such as SUS410. Examples of zinc alloys include Zn-Al alloys. Examples of copper alloys include brass. Examples of nickel alloys include Ni-P alloys.

[0024] Metals (including alloys) may be plated. Examples of the metals to be plated include nickel, zinc, chromium, iron, tin, copper, silver, platinum, and gold, and two or more metals may be used in combination. Examples of plating methods include electroplating, electroless plating, hot-dip plating, vacuum deposition, sputtering, and ion plating. Examples of plated metals include Ni-plated steel, Ni-plated copper, Zn-plated steel, and Zn-Ni-plated steel. Examples of the metal (base material) to be plated include cold-rolled steel sheets such as SPCC, SPCD, and SPCE, and copper sheets.

[0025] The aqueous surface treatment agent of this embodiment contains an ethylene-vinyl alcohol copolymer (A1), a carboxyl group-containing polymer (A2) having structural units derived from a radically polymerizable carboxyl group-containing monomer, and a trivalent chromium compound (B). Here, the aqueous surface treatment agent of this embodiment is preferably a hexavalent chromium-free aqueous surface treatment agent that does not contain any hexavalent chromium compound.

[0026] (Ethylene-vinyl alcohol copolymer (A1)) An ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH") (A1) constitutes an aqueous resin dispersion together with a carboxyl group-containing polymer (A2). The EVOH (A1) has ethylene structural units and vinyl alcohol structural units. The content of the ethylene structural units in the EVOH (A1) is preferably 25 to 44 mol %. When the content of the ethylene structural units is within this range, an aqueous resin dispersion having excellent dispersion stability can be obtained.

[0027] As the EVOH (A1), commercially available products can be used, such as "EVAL (registered trademark)" manufactured by Kuraray Co., Ltd. and "Soarnol (registered trademark)" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

[0028] (Carboxyl group-containing polymer (A2)) The carboxyl group-containing polymer (A2) has structural units derived from a radically polymerizable carboxyl group-containing monomer, i.e., the carboxyl group-containing polymer (A2) can be obtained by radically polymerizing radically polymerizable monomers that essentially contain a radically polymerizable carboxyl group-containing monomer.

[0029] Examples of radically polymerizable carboxyl group-containing monomers constituting the carboxyl group-containing polymer (A2) include unsaturated monocarboxylic acids such as itaconic acid, acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid; unsaturated dicarboxylic acids and anhydrides such as maleic acid, fumaric acid, citraconic acid, and chloromaleic acid; and monoesters of unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monomethyl itaconate, monoethyl itaconate, and monobutyl itaconate. These may be used alone or in combination of two or more. Metal salts or ammonium salts of these may also be used. Among these, itaconic acid, acrylic acid, and methacrylic acid are particularly preferred.

[0030] The mass ratio (A1) / (A2) of the EVOH (A1) to the mass of the carboxyl group-containing polymer (A2) is preferably 0.43 to 2.33.

[0031] In addition to the EVOH (A1) and the carboxyl group-containing polymer (A2), the aqueous resin dispersion may contain a polymer. The polymer has at least one structural unit selected from the group consisting of a radically polymerizable sulfonic acid monomer and a radically polymerizable monomer having neither a carboxyl group nor a sulfonic acid group. In addition to the above, the aqueous resin dispersion may contain a hydrophilic compound.

[0032] Examples of the radical polymerizable sulfonic acid monomer include methacrylate-based sulfonic acid monomers, acrylamide-based sulfonic acid monomers, allyl-based sulfonic acid monomers, vinyl-based sulfonic acid monomers, and styrene-based sulfonic acid monomers.

[0033] The radical polymerizable monomer having neither a carboxyl group nor a sulfonic acid group includes a radical polymerizable monomer represented by the following formula (a). CH2=C(R 1 )CO-(OCH2CH2) m -OR 2 … Formula (a) [In formula (a), R 1 represents hydrogen or a methyl group. 2 represents hydrogen or a methyl group, and m is an integer of 1 to 200.

[0034] Specific examples of the radical polymerizable monomer represented by formula (a) include (poly)ethylene glycol mono(meth)acrylate or methoxypolyethylene glycol (meth)acrylate, in which m is an integer of 1 to 200, or may have an amide bond, which provides dispersion stability to the aqueous resin dispersion.

[0035] In addition to the above, examples of radically polymerizable monomers that do not have a carboxyl group or a sulfonic acid group include radically polymerizable hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate, radically polymerizable amide group-containing monomers such as (meth)acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, N-methylol (meth)acrylamide, and N,N-dimethyl (meth)acrylamide, radically polymerizable silyl group-containing monomers such as γ-(meth)acryloxypropyltrimethoxysilane, radically polymerizable epoxy group-containing monomers such as glycidyl methacrylate, radically polymerizable ester group-containing monomers such as methyl (meth)acrylate and ethylene glycol dimethacrylate, and vinyl group-containing monomers such as vinyl acetate, styrene, acrylonitrile, and divinylbenzene. These monomers may be used alone or in combination of two or more.

[0036] Examples of the hydrophilic compound include polyethylene glycol (PEG), polyethylene oxide (PEO), polyoxyethylene group-containing polyvinyl alcohol (EO-PVA), polyvinylpyrrolidone (PVP), PVP-modified polyvinyl alcohol, etc. These may be used alone or in combination of two or more. Among these, polyethylene glycol (PEG), polyethylene oxide (PEO), and polyoxyethylene group-containing polyvinyl alcohol (EO-PVA) are particularly preferred.

[0037] The method for obtaining an aqueous resin dispersion from EVOH (A1) and a carboxyl group-containing polymer (A2) is not particularly limited, but examples thereof include a method including a step of obtaining a radical polymer by (co)polymerization in a solution containing EVOH (A1). When a hydrophilic compound is contained in the aqueous resin dispersion, it is preferable to include a step of obtaining a radical polymer by (co)polymerization in a solution containing EVOH (A1) and, if necessary, a hydrophilic compound. Conventionally known methods are used for the radical polymerization method, and conventionally known radical polymerization initiators are also used.

[0038] (Trivalent chromium compounds (B)) The trivalent chromium compound (B) is not particularly limited, but examples thereof include chromium(III) fluoride, chromium(III) nitrate, chromium(III) phosphate, chromium(III) acetate, chromium(III) chloride, chromium(III) sulfate, chromium(III) oxalate, chromium(III) formate, chromium(III) hydroxide, chromium(III) oxide, chromium(III) bromide, and chromium(III) iodide.

[0039] In this embodiment, the mass ratio (M / A1+A2) of the mass of trivalent chromium (M) contained in the trivalent chromium compound (B) to the total amount of the EVOH (A1) and the carboxyl group-containing polymer (A2) is 0.05 or more and 2.90 or less, and preferably 0.6 or more and 2.54 or less.

[0040] The content of trivalent chromium contained in the trivalent chromium compound (B) in the aqueous surface treatment agent of this embodiment is not particularly limited, but is, for example, 500 mass ppm or more and 60,000 mass ppm or less. In one embodiment, the content of trivalent chromium contained in the trivalent chromium compound (B) in the aqueous surface treatment agent is 1,000 mass ppm or more, 1,500 mass ppm or more, 2,000 mass ppm or more, 2,500 mass ppm or more, 3,000 mass ppm or more, 3,500 mass ppm or more, 4,000 mass ppm or more, 4,500 mass ppm or more, 5,000 mass ppm or more, 5,500 mass ppm or more, 6,000 mass ppm or more, 6,500 mass ppm or more, 7,000 mass ppm or more, 7,500 mass ppm or more, 8,000 mass ppm or more, 8,500 mass ppm or more, 9,000 mass ppm or more, 10,000 mass ppm or more, 11,000 mass ppm or more, 12,000 mass ppm or more, 13,000 mass ppm or more, 14,000 mass ppm or more, 15,000 mass ppm or more, 16,000 mass ppm or more, 17,000 mass ppm or more, 18,000 mass ppm or more, 19,000 mass ppm or more, 20,000 mass ppm or more, 21,000 mass ppm or more, 22,000 mass ppm or more, 23,000 mass ppm or more, 24,000 mass ppm or more, 25,000 mass ppm or more, 26,000 mass ppm or more, 27,000 mass ppm or more, 28,000 mass ppm or more, 29, ppm or more, 9500 mass ppm or more, 10000 mass ppm or more, 10500 mass ppm or more, 11000 mass ppm or more, 11500 mass ppm or more, 12000 mass ppm or more, 13000 mass ppm or more, 14000 mass ppm or more, 15000 mass ppm or more , 16000 mass ppm or more, 17000 mass ppm or more, 18000 mass ppm or more, 19000 mass ppm or more, 20000 mass ppm or more, 30000 mass ppm or more, 40000 mass ppm or more, 50000 mass ppm or more, 59500 mass ppm or more.In another embodiment, the content of trivalent chromium contained in the trivalent chromium compound (B) in the aqueous surface treatment agent is 59,500 ppm by mass or less, 50,000 ppm by mass or less, 40,000 ppm by mass or less, 30,000 ppm by mass or less, 20,000 ppm by mass or less, 19,000 ppm by mass or less, 18,000 ppm by mass or less, 17,000 ppm by mass or less, 16,000 ppm by mass or less, 15,000 ppm by mass or less, 14,000 ppm by mass or less, 13,000 ppm by mass or less, 12,000 ppm by mass or less, 11,500 ppm by mass or less, 11,000 ppm by mass or less, 10 500 mass ppm or less, 10000 mass ppm or less, 9500 mass ppm or less, 9000 mass ppm or less, 8500 mass ppm or less, 8000 mass ppm or less, 7500 mass ppm or less, 7000 mass ppm or less, 6500 mass ppm or less, 6000 mass ppm or less, 5 500 mass ppm or less, 5000 mass ppm or less, 4500 mass ppm or less, 4000 mass ppm or less, 3500 mass ppm or less, 3000 mass ppm or less, 2500 mass ppm or less, 2000 mass ppm or less, 1500 mass ppm or less, 1000 mass ppm or less.

[0041] (Hydroxy group crosslinkable compound (C1)) The aqueous surface treatment agent of this embodiment preferably further contains a hydroxyl group-crosslinking compound (C1) capable of reacting with the hydroxyl groups of the EVOH (A1) to form crosslinks. Examples of the hydroxyl group-crosslinking compound (C1) include one or more compounds selected from the group consisting of organotitanium compounds, organozirconium compounds, melamine resins, and blocked isocyanates. By including the hydroxyl group-crosslinking compound (C1) in the aqueous surface treatment agent, the electrolyte blocking properties of the film formed by the aqueous surface treatment agent are improved, resulting in improved electrolyte resistance.

[0042] (Carboxyl group cross-linking compound (C2)) The aqueous surface treatment agent of this embodiment preferably further contains a carboxyl group-crosslinking compound (C2) capable of reacting with the carboxyl groups of the carboxyl group-containing polymer (A2) to form crosslinks. Examples of the carboxyl group-crosslinking compound (C2) include one or more compounds selected from the group consisting of oxazoline compounds, silane coupling agents, epoxy compounds, and carbodiimide compounds. By including the carboxyl group-crosslinking compound (C2) in the aqueous surface treatment agent, the electrolyte blocking properties of the film formed by the aqueous surface treatment agent are improved, resulting in improved electrolyte resistance.

[0043] The total content of the hydroxyl group-crosslinking compound (C1) and the carboxyl group-crosslinking compound (C2) is preferably 0.05 to 30 parts by mass per 100 parts by mass of the solids content of the aqueous surface treatment agent. Compounds that fall under both the hydroxyl group-crosslinking compound (C1) and the carboxyl group-crosslinking compound (C2) may also be present. In this case, the content may be calculated by assuming that the compound falls under either the hydroxyl group-crosslinking compound (C1) or the carboxyl group-crosslinking compound (C2). When a compound containing a metal element, such as an organotitanium compound or an organozirconium compound, is used as the hydroxyl group-crosslinking compound (C1), the content of the compound is expressed as the metal element content.

[0044] (Organic chelating agent (D)) The aqueous surface treatment agent of this embodiment preferably further contains an organic chelating agent (D). This improves the storage stability of the aqueous surface treatment agent of this embodiment. Here, the organic chelating agent (D) is a ligand having multiple coordination sites per molecule (multidentate ligand) and has multiple functional groups per molecule.

[0045] The organic chelating agent (D) preferably has one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, a phosphonic acid group, a phosphoric acid group, and an amino group.

[0046] The organic chelating agent (D) having a hydroxyl group is not particularly limited, but examples thereof include ethylene glycol, propylene glycol, butylene glycol, hexanediol, thiodiglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, catechol, pyrogallol, hexahydroxybenzene, tartaric acid, malic acid, citric acid, ascorbic acid, N,N-bis(2-hydroxyethyl)glycine, hydroxyethylenediaminetriacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, N-(2-hydroxyethyl)ethylenediaminetri ... Examples of the hydroxybenzoic acid include dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 2,6-dihydroxy-4-methylbenzoic acid, 4-hydroxy-3,5-dimethylbenzoic acid, and glycerophosphate.

[0047] The organic chelating agent (D) having a carboxyl group is not particularly limited, and examples thereof include tartaric acid, malic acid, citric acid, ascorbic acid, succinic acid, itaconic acid, maleic acid, fumaric acid, phthalic acid, trimellitic acid, hemimellitic acid, trimesic acid, pyromellitic acid, mellitic acid, N,N-bis(2-hydroxyethyl)glycine, nitrilotriacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, ethylenediaminetetraacetic acid, 1,3-propanediaminetetraacetic acid, hydroxyethylenediaminetriacetic acid, N-(2-hydroxyethyl)ethylenedinitrilotriacetic acid, 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid, glycol ether diaminetetraacetic acid, trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, ethylenetriaminepentaacetic acid, triethylenetetramine-N,N,N',N'',N''',N'''-hexaacetic acid, and the like. Acetic acid, 1,3-propanedicarboxylic acid, 1,4-butanedicarboxylic acid, 1,5-heptanedicarboxylic acid, 1,2,3-butanetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,3,4,5,6-cyclohexanehexacarboxylic acid, gallic acid, pyrogallol-4-carboxylic acid, 2-hydroxybenzoic acid, 2,3-dicarboxylic acid Examples include hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 2,6-dihydroxy-4-methylbenzoic acid, 4-hydroxy-3,5-dimethylbenzoic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 3-phosphonopropionic acid, 4-phosphonobutyric acid, and phosphoserine.

[0048] The carboxyl groups of the organic chelating agent (D) having a carboxyl group may be partially or completely neutralized to form a metal salt or an ammonium salt.

[0049] The organic chelating agent (D) having a phosphonic acid group is not particularly limited, but examples thereof include methylene diphosphonic acid, 1,2-ethylene diphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilotris(methylphosphonic acid), 2-phosphonobutane-1,2,4-tricarboxylic acid, 3-phosphonopropionic acid, 4-phosphonobutyric acid, ethylenediaminetetramethylenephosphonic acid, and diethylenetriaminepentamethylenephosphonic acid.

[0050] The phosphonic acid groups of the organic chelating agent (D) may be partially or completely neutralized to form metal salts or ammonium salts.

[0051] The organic chelating agent (D) having a phosphate group is not particularly limited, but examples thereof include phytic acid, O-phosphorylethanolamine, phosphoserine, and glycerophosphate.

[0052] The phosphate groups of the organic chelating agent (D) may be partially or completely neutralized to form metal salts or ammonium salts.

[0053] The organic chelating agent (D) having an amino group is not particularly limited, but examples thereof include ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, diethylenetriamine, triethylenetetramine, O-phosphorylethanolamine, and phosphoserine.

[0054] The amino groups of the organic chelating agent (D) having amino groups may be partially or entirely neutralized with an acid to form salts.

[0055] The solid content of the organic chelating agent (D) in the aqueous surface treatment agent of this embodiment is not particularly limited, but is, for example, 0.1% by mass or more and 30% by mass or less. In one embodiment, the solid content of the organic chelating agent (D) in the aqueous surface treatment agent is 0.5% by mass or more, 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, 5% by mass or more, 6% by mass or more, 7% by mass or more, 8% by mass or more, 9% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, or 28% by mass or more. In another embodiment, the solids content of the organic chelating agent (D) in the aqueous surface treatment agent is 28% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, or 0.5% by mass or less.

[0056] The content of water in the aqueous surface treatment agent of this embodiment is not particularly limited, but is, for example, 60% by mass or more and 99.9% by mass or less.

[0057] The pH of the aqueous surface treatment agent of the present embodiment is preferably 1 or more and 11 or less, and more preferably 2 or more and 9 or less. When the pH of the aqueous surface treatment agent of the present embodiment is 1 or more and 11 or less, the storage stability of the aqueous surface treatment agent of the present embodiment is improved.

[0058] The aqueous surface treatment agent of this embodiment may further contain an acid or base as necessary to adjust the pH. Examples of acids include, but are not limited to, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, pyrophosphoric acid, metaphosphoric acid, and hydrofluoric acid; and organic acids such as acetic acid, oxalic acid, lactic acid, tartaric acid, fumaric acid, maleic acid, citric acid, benzoic acid, methanesulfonic acid, benzenesulfonic acid, and toluenesulfonic acid. Examples of bases include, but are not limited to, inorganic bases such as ammonia, sodium hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; and organic bases such as trimethylamine, diethylamine, triethylamine, and triethanolamine.

[0059] The aqueous surface treatment agent of the present embodiment may further contain known additives such as a surface conditioner, an antifoaming agent, a plasticizer, an antioxidant, an antibacterial agent, and a colorant, as needed.

[0060] Examples of the surface conditioner include nonionic or cationic surfactants, polyethylene oxide or polypropylene oxide adducts of polyacetylene glycol, and acetylene glycol compounds.

[0061] Examples of the antifoaming agent include mineral oil-based antifoaming agents, fatty acid-based antifoaming agents, and silicone-based antifoaming agents.

[0062] Examples of the plasticizer include 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, diethylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether, dipropylene glycol n-butyl ether, and diethylene glycol dibutyl ether.

[0063] Examples of antioxidants include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, etc. Specific examples include 2,6-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol, butylhydroxytoluene (BHT), 2,6-di-t-butyl-4-ethylphenol, 2,4,6-tri-t-butylphenol, 2,6-di-t-butyl-4-s-butylphenol, butylhydroxyanisole (BHA), tocopherol, 2,6-di-t-butyl-4-hydroxymethylphenol, n-octadecyl-β-(4′-hydroxy-3′,5′-di-t-butylphenyl)propionate, 2-t- Butyl-4-(N,N-dimethylaminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonic acid diethyl ester, propyl gallate, octyl gallate, lauryl gallate, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-methylenebis(2,6-di-t-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-dihydroxy-3,3'-bis(α -methylcyclohexyl)-5,5'-dimethyldiphenylmethane, 2,2'-dimethylenebis(6-α-methylbenzyl-p-cresol), 2,2'-ethylidenebis(4,6-di-t-butylphenol), 2,2'-butylidenebis(4-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], 1,6-hexanediol bis[3-(3,5-di -t-butyl-4-hydroxyphenyl)propionate], bis[2-t-butyl-4-methyl-6-(3-t-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 4,4'-thiobis(6-t-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 2,2'-thiobis(4-methyl-6-t-butylphenol), bis(3,5-di-t-butyl-4-hydroxybenzyl) sulfide, 4,4'-di- and trithiobis(2,6-di-t-butylphenol), 2,2-thiodiethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy3',5'-di-t-butylanilino)-1,3,5-triazine, N,N'-hexamethylenebis-(3,5-di-t-butyl-4 -Hydroxyhydrocinnamide, N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine, calcium (3,5-di-t-butyl-4-hydroxybenzyl monoethylphosphonate), alkylated bisphenol, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-t-butyl-4-hydroxy phenyl) isocyanurate, tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris[{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy}ethyl]isocyanurate, tetrakis[methylene-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate]methane, butylic acid, [3,3-bis(3-t-butyl- 4-hydroxyphenyl)butyric acid]ethylene, triphenyl phosphite, diphenyl nonylphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, tris(nonylphenyl) phosphite, tris(mono and di-mixed nonylphenyl) phosphite, diphenyl isooctyl phosphite, 2,2'-methylenebis(4,6-di-t-butylphenyl) octyl phosphite, diphenyl isodecyl phosphite, diphenyl monotridecyl phosphite, 2,2'-ethylidenebis(4,6-di-t-butylphenol)fluorophosphite, phenyl diisodecyl phosphite, phenyl ditridecyl phosphite, tris(2-ethylhexyl) phosphite, triisodecyl phosphite, tritridecyl phosphite, dibutyl hydrogen phosphite, trilauryl trithiophosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite, 4,4'-isopropylidenediphenol alkyl (C12-C15) phosphite, 4,4'-butylidenebis(3-methyl -6-t-butylphenyl)ditridecyl phosphite, distearyl pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, cyclic neopentanetetraylbis(2,6-di-t-butyl-4-methylphenyl)phosphite, phenyl bisphenol A pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphite, 1,1,3-tris(2-methyl-4-ditridecyl phosphite), Phosphite-5-t-butylphenyl)butane, tetraphenyltetratridecylpentaerythritol tetraphosphite, zinc dialkyldithiophosphate (ZnDTP), 3,4,5,6-dibenzo-1,2-oxaphosphane-2-oxide, 3,5-di-t-butyl-4-hydroxybenzylphosphonic acid diethyl ester, hydrogenated bisphenol A phosphite polymer, 3,3'-thiodipropionate dilauryl (DLTTDP), 3,3'-thiodipropionate ditridecyl, 3,3'-thiodipropionate dimyristyl (DMTDP), Examples of such thiodipropionates include distearyl 3,3'-thiodipropionate (DSTDP), laurylstearyl 3,3'-thiodipropionate, pentaerythritol tetrakis(β-laurylthiopropionate), stearylthiopropionamide, bis[2-methyl-4-(3-n-alkyl(C12-C14)thiopropionyloxy)-5-t-butylphenyl]sulfide, dioctadecyl disulfide, 2-mercaptobenzimidazole, 2-mercapto-6-methylbenzimidazole, and 1,1'-thiobis(2-naphthol).

[0064] Examples of antibacterial agents include zinc pyrithione, 2-(4-thiazolyl)benzimidazole, 1,2-benzisothiazoline, 2-n-octyl-4-isothiazolin-3-one, N-(fluorodichloromethylthio)phthalimide, N,N-dimethyl-N'-phenyl-N'-(fluorodichloromethylthio)sulfamide, 2-benzimidazole methylcarbamate, bis(dimethylthiocarbamoyl)disulfide, N-(trichloromethylthio)-4-cyclohexane-1,2-dicarboximide, barium metaborate, allyl isothiocyanate; polyoxyalkylene trialkylammonium, organic silicone quaternary ammonium salts, quaternary ammonium salts such as hexamethylene biguanide hydrochloride; quaternary phosphonium salts such as tri-n-butyltetradecylphosphonium chloride; polyphenol-based antibacterial agents, phenylamide-based antibacterial agents, and biquanide-based antibacterial agents.

[0065] Examples of colorants include organic pigments such as quinacridones, anthraquinones, perylenes, perinones, diketopyrrolopyrroles, isoindolinones, condensed azos, benzimidazolones, monoazos, insoluble azos, naphthols, flavanthrones, anthrapyrimidines, quinophthalones, pyranthrones, pyrazolones, thioindigos, anthanthrones, dioxazines, phthalocyanines, and indanthrones; metal complexes such as nickel dioxin yellow and copper azomethine yellow; metal oxides such as titanium oxide, iron oxide, and zinc oxide; metal salts such as barium sulfate and calcium carbonate; and inorganic pigments such as carbon black, aluminum, and mica; and dyes such as azos, quinolines, stilbenes, thiazoles, indigoids, anthraquinones, and oxazines.

[0066] The aqueous surface treatment agent of this embodiment contains predetermined amounts of EVOH (A1), a carboxyl group-containing polymer (A2), and a trivalent chromium compound (B). This allows for excellent coating workability and storage stability, and the surface-treated metal of this embodiment (described below) exhibits sufficient adhesion to a laminate film. While aqueous surface treatment agents simply containing EVOH (A1), a carboxyl group-containing polymer (A2), and a trivalent chromium compound (B) can improve the corrosion resistance of the surface-treated metal, the aqueous surface treatment agent of this embodiment can improve the adhesion to the laminate film and electrolyte resistance of the surface-treated metal of this embodiment (described below), as well as corrosion resistance. Therefore, the aqueous surface treatment agent of this embodiment is particularly suitable for use in the production of surface-treated metals that require adhesion to a laminate film, electrolyte resistance, and corrosion resistance after lamination.

[0067] [Surface-treated metal] The surface-treated metal of this embodiment has a coating formed by surface treating the metal with the aqueous surface treatment agent of this embodiment.

[0068] The shape of the metal is not particularly limited, and examples thereof include a foil or plate. When a foil or plate metal is used, only one side may be surface-treated with an aqueous surface treatment agent, or both sides may be surface-treated with an aqueous surface treatment agent. When both sides are surface-treated, both sides may be surface-treated with a single aqueous surface treatment agent, or each side may be surface-treated with an aqueous surface treatment agent having a different composition.

[0069] The surface-treated metal of this embodiment may be a metal having a coating that has been laminated. That is, a laminate film may be adhered to the metal having a coating. When a foil-like or plate-like metal having a coating is used, a laminate film may be adhered to only one side, or may be adhered to both sides. Furthermore, when a laminate film is adhered to both sides, the same type of laminate film may be adhered to both sides, or a different type of laminate film may be adhered to each side.

[0070] The material constituting the laminate film is not particularly limited, but examples thereof include polyethylene resins, polypropylene resins, polycarbonate resins, polyvinyl alcohol resins, polyvinyl acetal resins, polyvinylidene chloride resins, polyvinyl acetate resins, polyethylene terephthalate resins, polyethylene naphthalate resins, polybutylene terephthalate resins, polyethylene isophthalate resins, copolymer polyester resins, polyester resins, polyamide resins, polyimide resins, polyetherimide resins, polyphenylene sulfide resins, fluorine-containing resins, silicone resins, nylon resins, phenolic resins, (meth)acrylic resins, epoxy resins, polymetaxylylene azibamide resins, etc. These materials may be used alone or in combination of two or more.

[0071] The laminate film may be uniaxially stretched or biaxially stretched.

[0072] The laminate film may be a single-layer film or a multilayer film in which multiple (types of) films are laminated. When multiple films are laminated, the films may be laminated via an adhesive, or may be laminated directly without an adhesive. The adhesive may be a one-component curing adhesive or a two-component curing adhesive. Examples of resin components constituting the adhesive include polyester resins, polyether resins, polyurethane resins, epoxy resins, phenolic resins, polyamide resins, polyolefin resins, polyvinyl acetate resins, cellulose resins, (meth)acrylic resins, polyimide resins, amino resins, rubber, and silicone resins. Examples of methods for directly laminating multiple films without an adhesive include methods in which the films are bonded in a hot-melt state, such as coextrusion, sand lamination, and thermal lamination.

[0073] The surface-treated metal of this embodiment may have layers (other layers) other than the coating and the laminate film. The other layers may be placed between the coating and the laminate film, or may be placed on the laminate film. Alternatively, the other layers may be placed on the coating without using a laminate film.

[0074] The other layers are not particularly limited, and examples thereof include known layers such as an adhesive layer, a coating film, a hard coat layer, an antifouling layer, an antiglare layer, a design layer, a printed layer, a polarizing plate, a colored layer, a liquid crystal layer, a light guide plate, a transparent conductive film, a spacer, etc. The other layers may be used singly or in combination of two or more.

[0075] The adhesive layer may be formed from a one-component adhesive or a two-component adhesive.

[0076] Examples of resin components constituting the adhesive that can be used to form the adhesive layer include polyolefin resins, polyester resins, polyether resins, polyurethane resins, polycarbonate resins, epoxy resins, phenolic resins, polyamide resins, polyvinyl acetate resins, cellulose resins, (meth)acrylic resins, polyimide resins, amino resins, chloroprene rubber resins, nitrile rubber resins, styrene-butadiene rubber resins, silicone resins, and fluorinated ethylene-propylene copolymer resins. These resin components may be used alone or in combination of two or more. Examples of combinations of two or more adhesives include polyurethane resins and modified polyolefin resins, polyamide resins and acid-modified polyolefin resins, polyamide resins and metal-modified polyolefin resins, polyamide resins and polyester resins, polyester resins and acid-modified polyolefin resins, and polyester resins and metal-modified polyolefin resins.

[0077] Polyolefin resins include acid-modified polyolefin resins and metal-modified polyolefin resins. Examples of acid-modified polyolefin resins include polyolefin resins obtained by acid-modifying polyolefins with unsaturated carboxylic acids or their anhydrides. Examples of polyolefin resins obtained by acid-modifying polyolefins with unsaturated carboxylic acids or their anhydrides include maleic anhydride-modified polypropylene. Commercially available acid-modified polyolefin resins include Admer (NB508, NF518, LB548, QB510, QB550, LB458, NF528, LF128, LF308, NF308, NF548, NF558, SF600, SF700, SF731, SF715, SE800, NE060, NE065, NE090, XE070, HE040, QE060, QF500, QF551, QF570, NR106, NS101, etc.) manufactured by Mitsui Chemicals, and Unistall (R-200X, R-303XE, E-200EM, A-200EM, etc.) manufactured by Mitsui Chemicals. 00PM, A-201PM, H-100, H-200, XP01A, XP01B / 11B, XP03F, XP04A, etc.), Mitsubishi Chemical's Modic (P502, P512VB, P553A, P674V, P565, P555, P908H511, H503, H514, L502, L504, M142, M512, M522, M545, A543, F502, F573, F534A, etc.), and Unitika's Arrow Base (SB-1200, SE-1200, SD-1200, DA1010, DC-1010, YA-6010, etc.).

[0078] The method for forming the adhesive layer is not particularly limited, but examples thereof include an extrusion molding method and a dispersion method.

[0079] The surface-treated metal of this embodiment can be applied to battery exterior materials, but may also be applied to, for example, food packaging materials, food can bodies or lids, beverage can bodies or lids, soft packaging materials or surface protective materials containing metal foil such as aluminum pouches, battery separators, tab leads, condenser cases, heat exchangers, electronic device housings, metal building materials, vehicle bodies, engine parts or chassis parts, aircraft bodies, main wings, frames, fuel tanks, engine turbines, engine fans or parts, railway vehicle bodies, bogies or parts, ships, rocket parts, bicycle parts, vending machines, elevator car side panels, governors or hoists, escalator steps or interior panels, machine tools, injection molding machines, structural members or drive members for industrial robots, semiconductor manufacturing equipment, displays, submarines, traffic lights, automatic looms, tunnel boring machines, pipelines, road signs, generators, waste incinerators, exhaust gas treatment devices, motors, transformers, electronic circuits, light bulbs, photomultiplier tubes, golf clubs, antennas, bolts, nuts, screws, and the like.

[0080] [Surface treatment method] The surface treatment method of this embodiment includes a film formation step of forming a film by treating the surface of a metal with the aqueous surface treatment agent of this embodiment.

[0081] In the film forming step, for example, the aqueous surface treatment agent of this embodiment is applied to the surface of the metal, and then dried.

[0082] The method for applying the aqueous surface treatment agent of the present embodiment is not particularly limited, and examples thereof include roll coater coating, gravure coater coating, reverse coater coating, slot die coater coating, lip coater coating, knife coater coating, blade coater coating, chamber doctor coater coating, air knife coater coating, curtain coat coating, spin coat coating, brush coating, roller coating, bar coater coating, dip coating, applicator coating, spray coating, flow coating, and combinations thereof.

[0083] The drying method is not particularly limited, and known methods can be used, including heat drying methods such as drying using an oven, drying by forced circulation of hot air, and drying in an electromagnetic induction heating furnace using an IH heater or the like. The heat drying conditions can be, for example, a temperature of 40°C or higher and 230°C or lower for 2 seconds or longer and 180 seconds or shorter. Here, the conditions set for heat drying, such as air volume and air speed, can be set as desired.

[0084] In the film formation step, the aqueous surface treatment agent of the present embodiment may be applied to the surface of the metal while being dried. For example, the aqueous surface treatment agent of the present embodiment may be applied to the surface of a preheated metal and then dried.

[0085] The amount of film formed after drying in the film formation process is 0.1 mg / m 2 More than 5000mg / m 2 Preferably, it is 1 mg / m or less. 2 More than 500mg / m 2 It is even more preferable that:

[0086] The surface treatment method of this embodiment may further include a laminating step of laminating the metal having the coating.

[0087] The method for laminating the metal having the coating is not particularly limited, but known methods such as dry lamination, heat lamination, and extrusion lamination can be used.

[0088] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments may be modified as appropriate within the scope of the spirit of the present invention. [Example]

[0089] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0090] [Synthesis Example 1] The aqueous resin dispersion of Synthesis Example 1 was produced by the following method: A flask equipped with a stirrer, a cooler, a temperature controller, and two dropping funnels was charged with 30% by mass of pellet-shaped EVOH (A1) and 9 times by mass of a mixed solution of water and methanol (water:methanol=1:1 by mass ratio), heated to 75°C, and vigorously stirred for 1 hour or more to obtain an EVOH (A1) solution.

[0091] Next, a methanol solution of 20% by mass of itaconic acid and 50% by mass of acrylic acid as monomers for the carboxyl group-containing polymer (A2) and an aqueous solution of 0.6% by mass of ammonium persulfate were placed in separate dropping funnels and added dropwise to the EVOH (A1) solution under a nitrogen atmosphere. The liquid temperature was kept at 75°C and the addition was carried out over 30 minutes. After the addition was completed, the mixture was stirred at the same temperature for 2 hours.

[0092] Next, a carboxyl group equivalent of ammonia water (diluted with the same amount of methanol as the water in the ammonia water) was added dropwise over about 20 minutes to neutralize. Then, a cooling tube for removing the solvent was attached, and the mixture was heated while adding water to distill off the methanol and replace the medium with water. After that, the mixture was cooled and filtered to obtain the aqueous resin dispersion of Synthesis Example 1.

[0093] [Synthesis Examples 2 to 6] Aqueous resin dispersions of Synthesis Examples 2 to 6 were obtained in the same manner as in Synthesis Example 1, except that the types and contents of the EVOH (A1) and the carboxyl group-containing polymer (A2) monomers were changed as shown in Table 1. The values ​​in Table 1 indicate the blending ratios (% by mass).

[0094] [Table 1]

[0095] [Examples 1 to 29, Comparative Examples 1 to 7] An aqueous surface treatment agent was obtained by mixing ion-exchanged water, an aqueous resin dispersion, a trivalent chromium compound (B), a hydroxyl group-crosslinking compound (C1), a carboxyl group-crosslinking compound (C2), and an organic chelating agent (D). In Comparative Examples 5 to 7, the aqueous resin dispersions shown in Table 2 were used instead of the aqueous resin dispersions containing EVOH (A1) and carboxyl group-containing polymer (A2) according to Synthesis Examples 1 to 6. In Comparative Example 3, no aqueous resin dispersion was used. In Comparative Example 7, EVOH was dissolved at 75°C in a mixed solution of water and methanol (water:methanol = 1:1 by mass) instead of ion-exchanged water.

[0096] The types and contents of the aqueous resin dispersion, trivalent chromium compound (B), hydroxyl group cross-linking compound (C1), carboxyl group cross-linking compound (C2), and organic chelating agent (D) are shown in Table 2. The contents of C1a and C1b shown in Table 2 are expressed in terms of metal elements.

[0097] [Table 2]

[0098] The definitions of the abbreviations in Table 2 are as follows: PAA: Polyacrylic acid; Jurimer AC-10L (manufactured by Toagosei) PVA: Polyvinyl alcohol; Poval 105MC (Kuraray) EVOH: EVOH (A1) used in Synthesis Example 1

[0099] B1: Chromium(III) fluoride B2: Chromium(III) nitrate B3: Chromium(III) phosphate

[0100] C1a: Titanium compound: Orgatics TC300 (Matsumoto Fine Chemical) C1b: Zirconium compound; Zircosol AC7 (manufactured by Daiichi Kigenso Kagaku) C1c: Methylated melamine resin; Cymel 370N (manufactured by Allnex Japan) C1d: Blocked isocyanate: Trixene Aqua BI 220 (GSI Creos) C2a: Oxazoline group-containing polymer; Epocross WS300 (manufactured by Nippon Shokubai) C2b: Silane coupling agent: KBM-403 (Shin-Etsu Silicone) C2c: Epoxy compound: Denacol EX313 (Nagase ChemteX) C2d: Carbodiimide compound: Carbodilite V-02 (Nisshinbo Chemical)

[0101] D1: 1,3-propanediaminetetraacetic acid D2: 2-phosphonobutane-1,2,4-tricarboxylic acid D3: Ethylenediaminetetramethylenephosphonic acid D4: Phytic acid

[0102] [Primary rust prevention treatment (film formation)] A 40 μm-thick metal plate (see Table 3) was surface-treated with the aqueous surface treatment agent to form a coating. Specifically, the metal plate was degreased with a 2% by weight diluted solution of Surf Cleaner 330 (manufactured by Nippon Paint Surf Chemicals) at 65°C for 3 seconds. Next, the aqueous surface treatment agent was applied using a bar coater (#6), and the plate was then dried in a hot air oven at a temperature of 190°C or higher for 2 minutes.

[0103] [Lamination method] The metal plate on which the film was formed was laminated. Specifically, a maleic anhydride-modified polypropylene dispersion was applied as an adhesive at a dry coating amount of 3 g / m. 2 The adhesive layer was formed by applying the adhesive to the film formed on the surface of the metal plate and then drying the film. Next, a polypropylene film was heat-pressed onto the metal plate with the adhesive layer formed thereon at 190°C and 0.38 MPa.

[0104] [Adhesion of laminate film] The laminated metal plate was cut into a size of 150 mm x 15 mm to obtain a test piece. Next, the peel strength was measured when the polypropylene film was peeled from the metal plate of the test piece at an angle of 180 degrees at a peeling speed of 50 mm / min using a bench-top precision universal testing machine Autograph AGS-5KNX (Shimadzu Corporation), and the adhesion of the laminate film was evaluated.

[0105] [Electrolyte resistance] 1000 ppm of ion-exchanged water was added to electrolyte LBG-00015 (Kishida Chemical Co., Ltd.), which was 1M LiPF6 dissolved in a mixed solvent of ethylene carbonate / dimethyl carbonate / diethyl carbonate (volume ratio 1 / 1 / 1), to obtain a test electrolyte.

[0106] The test piece was immersed in the test electrolyte at 85° C. for 14 days, and then the peel strength was measured in the same manner as above to evaluate the electrolyte resistance.

[0107] Table 3 shows the evaluation results of the adhesion and electrolyte resistance of the laminate film on the laminated metal plate.

[0108] [Table 3]

[0109] The definitions of the abbreviations in Table 3 are as follows: Al plate: Aluminum alloy plate (8079 material) SUS plate: Stainless steel plate (SUS304) Ni-plated steel sheet: Nickel-plated steel sheet (base material: SPCC) Ni-plated Cu plate: Nickel-plated copper plate EG plate: Electrogalvanized steel plate (base material: SPCC)

[0110] The results in Table 3 clearly show that the aqueous surface treatment agents according to the examples have higher adhesion and electrolyte resistance than the aqueous surface treatment agents according to the comparative examples.

Claims

1. An aqueous surface treatment agent used for metal surface treatment, The composition comprises an ethylene-vinyl alcohol copolymer (A1), a carboxyl group-containing polymer (A2) having a structural unit derived from a radically polymerizable carboxyl group-containing monomer, and a trivalent chromium compound (B), the mass ratio (M / A1+A2) of the mass of trivalent chromium (M) contained in the trivalent chromium compound (B) to the total amount of the ethylene-vinyl alcohol copolymer (A1) and the carboxyl group-containing polymer (A2) having a structural unit derived from a radically polymerizable carboxyl group-containing monomer is 0.05 or more and 2.90 or less.

2. 2. The aqueous surface treatment agent according to claim 1, further comprising a hydroxyl group-crosslinking compound (C1) capable of reacting with hydroxyl groups of the ethylene-vinyl alcohol copolymer (A1) to form crosslinks.

3. 3. The aqueous surface treatment agent according to claim 2, wherein the hydroxyl group-crosslinking compound (C1) is one or more compounds selected from the group consisting of organic titanium compounds, organic zirconium compounds, melamine resins, and blocked isocyanates.

4. 4. The aqueous surface treatment agent according to claim 1, further comprising a carboxyl group-crosslinking compound (C2) capable of reacting with a carboxyl group in the carboxyl group-containing polymer (A2) having a structural unit derived from a radically polymerizable carboxyl group-containing monomer to form a crosslink.

5. 5. The aqueous surface treatment agent according to claim 4, wherein the carboxyl group-crosslinking compound (C2) is one or more compounds selected from the group consisting of oxazoline compounds, silane coupling agents, epoxy compounds, and carbodiimide compounds.

6. The aqueous surface treatment agent according to claim 1 , further comprising an organic chelating agent (D).

7. 7. The aqueous surface treatment agent according to claim 6, wherein the organic chelating agent (D) has one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, a phosphonic acid group, a phosphoric acid group, and an amino group.

8. A surface-treated metal having a coating formed by treating the metal surface with the aqueous surface treatment agent according to any one of claims 1 to 7.

9. The surface-treated metal according to claim 8, wherein the metal is aluminum or an aluminum alloy, iron or an iron alloy, or copper or a copper alloy.

10. The surface-treated metal according to claim 8 or 9, wherein the metal is plated.

11. The surface-treated metal according to any one of claims 8 to 10, wherein the metal having the coating is laminated.

12. The surface-treated metal according to claim 11, which is an exterior material for a battery.

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