Aqueous metal surface treatment agent and method for producing metal foil laminate

Abstract

To provide an aqueous surface treatment agent which is capable of improving adhesion and electrolyte solution resistance when laminating a metal.SOLUTION: An aqueous metal surface treatment agent is used for surface treatment of a metal and includes a trivalent chromium compound (A), a water-soluble or water-dispersible acrylic resin (B), and a phosphoric acid compound (C). The water-soluble or water-dispersible acrylic resin (B) has a weight average molecular weight of 50,000 to 1,000,000 inclusive, and a solid acid value of more than 740 mgKOH / g.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous metal surface treatment agent and a method for manufacturing a metal foil laminate.

Background Art

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

[0003] In order to maintain the aesthetic appearance and corrosion resistance of the laminated metal, it is important to improve the adhesion of the laminate film. For example, a method of forming a chemical conversion treatment layer on one or both surfaces of an aluminum foil is known.

[0004] As a method of forming a chemical conversion treatment layer on the aluminum surface, for example, a method using a surface treatment agent containing a water-soluble trivalent chromium compound and an aqueous organic polymer compound is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Here, when applying the laminated metal to an exterior material for a battery, it is desired to improve the adhesion and the electrolyte resistance.

[0007] An object of the present invention is to provide an aqueous surface treatment agent capable of improving the adhesion and the electrolyte resistance when laminating a metal.

Means for Solving the Problems

[0008] (1) The present disclosure relates to an aqueous metal surface treatment agent used for surface treatment of metals, which contains a trivalent chromium compound (A), a water-soluble or water-dispersible acrylic resin (B), and a phosphoric acid compound (C), wherein the water-soluble or water-dispersible acrylic resin (B) has a weight average molecular weight of 50,000 or more and 1,000,000 or less, and a solid content acid value exceeding 740 mgKOH / g.

[0009] (2) With respect to the total solid content of the aqueous metal surface treatment agent, the mass ratio of trivalent chromium contained in the trivalent chromium compound (A) is 5% or more and 15% or less as trivalent chromium, and with respect to the total solid content of the aqueous metal surface treatment agent, the solid content mass ratio of the phosphoric acid compound (C) is 5% or more and 40% or less as phosphate ions. The aqueous metal surface treatment agent according to (1).

[0010] (3) The aqueous metal surface treatment agent further contains nitrate ions (D), and the molar ratio (A / D) of the trivalent chromium compound (A) to the nitrate ions (D) is 0.3 or more and 0.4 or less. The aqueous metal surface treatment agent according to (1) or (2).

[0011] (4) Further, the present disclosure relates to a method for manufacturing a metal foil laminate, which includes a surface treatment step of treating at least one surface of a metal foil, and a lamination step of laminating a film on the surface of the metal foil treated in the surface treatment step, wherein the aqueous metal surface treatment agent used in the surface treatment step contains a trivalent chromium compound (A), a water-soluble or water-dispersible acrylic resin (B), and a phosphoric acid compound (C), and the water-soluble or water-dispersible acrylic resin (B) has a weight average molecular weight of 50,000 or more and 1,000,000 or less, and a solid content acid value exceeding 740 mgKOH / g.

[0012] (5) The mass ratio of trivalent chromium contained in the trivalent chromium compound (A) is 5% or more and 15% or less as trivalent chromium with respect to the total solid content of the aqueous metal surface treatment agent, and the solid content mass ratio of the phosphoric acid compound (C) is 5% or more and 40% or less as phosphate ions with respect to the total solid content of the aqueous metal surface treatment agent. The method for manufacturing a metal foil laminate according to (4).

[0013] (6) The aqueous metal surface treatment agent further contains nitrate ions (D), and the molar ratio (A / D) of the trivalent chromium compound (A) to the nitrate ions (D) is 0.3 or more and 0.4 or less. The method for manufacturing a metal foil laminate according to (4) or (5). [Advantages of the Invention]

[0014] According to the present invention, when laminating a metal, it is possible to provide an aqueous surface treatment agent capable of improving adhesion and electrolytic solution resistance. [Embodiments for Carrying Out the Invention]

[0015] Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the descriptions of the following embodiments.

[0016] [Aqueous Surface Treatment Agent] The aqueous surface treatment agent of the present embodiment is used for surface treatment of metals.

[0017] The metal to be surface-treated is not particularly limited, and examples thereof include iron, zinc, aluminum, copper, nickel, etc., and two or more kinds 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, from the viewpoints of workability and adhesion, aluminum or an aluminum alloy, iron or an iron alloy, or copper or a copper alloy is preferable, and aluminum or an aluminum alloy is more preferable. Examples of aluminum alloys include Al-Cu-based alloys, Al-Mn-based alloys, Al-Si-based alloys, Al-Mg-based alloys, Al-Mg-Si-based alloys, Al-Zn-Mg-based alloys, aluminum die cast (ADC material), etc. When the surface-treated metal of the present embodiment described later is used as an exterior material for a battery, it is preferable to use 8079 material or the like as the aluminum alloy. Examples of aluminum alloys applicable to other uses include 3004 material, 3104 material, 3005 material, etc. for beverage and food can bodies, 5052 material, 5182 material, etc. for beverage and food can lids, 1050 material, 1100 material, 1200 material, etc. for dry battery containers, 8021 material, etc. for electrode materials. Examples of iron alloys include cold-rolled steel sheets such as SPCC, SPCD, SPCE, and stainless steel (SUS). Examples of SUS include austenitic stainless steels such as SUS304, SUS301, SUS316, ferritic stainless steels such as SUS430, and martensitic stainless steels such as SUS410. Examples of zinc alloys include Zn-Al-based alloys. Examples of copper alloys include brass. Examples of nickel alloys include Ni-P alloys.

[0018] The metal that may be an alloy may be subjected to plating. Examples of the plating types include metals such as nickel, zinc, chromium, iron, tin, copper, silver, platinum, gold, etc., and two or more metals may be used in combination. Examples of the plating methods include electroplating, electroless plating, hot dip plating, vacuum evaporation, sputtering, ion plating, etc. Examples of the metal being plated include Ni-plated steel materials, Ni-plated copper materials, Zn-plated steel materials, Zn-Ni plated steel materials, etc. As the metal (base material) to be plated, for example, cold-rolled steel sheets such as SPCC, SPCD, SPCE, copper plates, etc. can be used.

[0019] The aqueous metal surface treatment agent according to this embodiment contains a trivalent chromium compound (A), a water-soluble or water-dispersible acrylic resin (B), and a phosphoric acid compound (C). Further, it is preferably further contains nitrate ions (D).

[0020] The aqueous surface treatment agent of this embodiment may contain hexavalent chromium. In this case, the content of hexavalent chromium in the aqueous surface treatment agent of this embodiment is, for example, less than 0.04% by mass, less than 0.02% by mass, less than 0.01% by mass, less than 0.001% by mass, less than 0.0001% by mass, less than 0.00001% by mass or less than 0.000001% by mass. The content of hexavalent chromium in the aqueous surface treatment agent of this embodiment is preferably minimized, that is, it is preferably trace, and most preferably 0% by mass. The film formed by surface-treating a metal with the aqueous surface treatment agent of this embodiment preferably substantially does not contain hexavalent chromium, and most preferably does not contain hexavalent chromium.

[0021] (Trivalent chromium compound (A)) When the trivalent chromium compound (A) is contained in the aqueous surface treatment agent, the electrolytic solution resistance is improved when laminating the metal. The electrolytic solution may contain a fluorine compound such as LiPF6. The fluorine compound reacts with water to generate hydrofluoric acid, and hydrofluoric acid causes corrosion of metals such as aluminum. The trivalent chromium compound (A) can form a film excellent in electrolytic solution resistance against the above-mentioned electrolytic solution.

[0022] The trivalent chromium compound (A) is not particularly limited, and 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, chromium(III) iodide, and the like.

[0023] The content of the trivalent chromium compound (A) is preferably 5% or more and 15% or less in terms of trivalent chromium conversion (chromium concentration) contained in the trivalent chromium compound (A) with respect to the total solid content of the aqueous surface treatment agent. Thereby, the electrolytic solution resistance can be improved when laminating the metal. The trivalent chromium concentration in the aqueous surface treatment agent is more preferably 5% or more and 10% or less.

[0024] The concentration of the trivalent chromium compound (A) is preferably 0.1% or more and 0.45% or less in the aqueous surface treatment agent in terms of trivalent chromium conversion (chromium concentration) contained in the trivalent chromium compound (A). Thereby, the electrolytic solution resistance can be improved when laminating the metal. The trivalent chromium concentration in the aqueous surface treatment agent is more preferably 0.15% or more and 0.45% or less.

[0025] (Water-soluble or water-dispersible acrylic resin (B)) The water-soluble or water-dispersible acrylic resin (B) is contained in the aqueous surface treatment agent to improve the adhesion when laminating a metal. The water-soluble or water-dispersible acrylic resin (B) contains, for example, a structural unit derived from a monomer having a carboxyl group. The monomer having a carboxyl group is not particularly limited, and examples thereof include (meth)acrylic acid, crotonic acid, isocrotonic acid, (meth)acrylic acid dimer, ε-caprolactone adduct of (meth)acrylic acid, and the like. Examples of monomers having a carboxyl group other than the above include unsaturated dibasic acids such as maleic acid, fumaric acid, and itaconic acid, and their half esters, half amides, half thioesters, etc., and two or more kinds may be used in combination.

[0026] From the viewpoint of electrolytic solution resistance when laminating a metal, the water-soluble or water-dispersible acrylic resin (B) is preferably poly(meth)acrylic acid, and more preferably polyacrylic acid.

[0027] Examples of commercially available polyacrylic acids include Julimer AC-10L, AC-10H, AC-20L, SH-5 (all manufactured by Toagosei Co., Ltd.), and the like.

[0028] The water-soluble or water-dispersible acrylic resin (B) may further contain a structural unit derived from a monomer having a hydroxyl group.

[0029] The monomers having a hydroxyl group are not particularly limited. For example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1,4-cyclohexanedimethanol mono (meth)acrylate, glycerin mono (meth)acrylate, (meth)allyl alcohol, N-methylol (meth)acrylamide, N-(2-hydroxyethyl)acrylamide, N-(2-hydroxypropyl)acrylamide, ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate, etc. may be mentioned, and two or more of them may be used in combination.

[0030] The water-soluble or water-dispersible acrylic resin (B) may further contain structural units derived from monomers other than the above (other monomers).

[0031] The other monomers are not particularly limited. For example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, 1-methylethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, dihydrodicyclopentadienyl (meth)acrylate, methoxypolyethylene (meth)acrylate, etc. may be mentioned. Other monomers other than the above include styrene, α-methylstyrene, vinyl ketone, t-butylstyrene, p-chlorostyrene, vinyl naphthalene, acrylonitrile, methacrylonitrile, ethylene, propylene, vinyl acetate, vinyl propionate, butadiene, isoprene, etc., and two or more of them may be used in combination.

[0032] The weight average molecular weight of the water-soluble or water-dispersible acrylic resin (B) is 50,000 or more and 1,000,000 or less. Thereby, a film excellent in adhesion and electrolytic solution resistance can be formed. The weight average molecular weight of the water-soluble or water-dispersible acrylic resin (B) is preferably 50,000 or more and 250,000 or less. When the weight average molecular weight of the water-soluble or water-dispersible acrylic resin (B) is less than 50,000, the adhesion of the laminate film decreases when laminating to a metal. When it exceeds 1,000,000, the aqueous surface treatment agent tends to gel and handling becomes difficult.

[0033] In this specification and the claims, the weight average molecular weight of the water-soluble or water-dispersible acrylic resin (B) is the molecular weight determined by the GPC method using polyethylene oxide as a standard substance.

[0034] The solid content acid value of the water-soluble or water-dispersible acrylic resin (B) is more than 740 mgKOH / g. Thereby, a film excellent in adhesion and electrolytic solution resistance can be formed. The solid content acid value of the water-soluble or water-dispersible acrylic resin (B) may be 779 mgKOH / g or less.

[0035] In this specification and the claims, the solid content acid value of the water-soluble or water-dispersible acrylic resin (B) means the theoretical value of the solid content acid value calculated by calculating the amount of potassium hydroxide (unit: mg) required to neutralize the acid groups contained in 1 g of the solid content of the acrylic resin based on the charging ratio of each monomer used in the polymerization of the acrylic resin. The solid content acid value of the water-soluble or water-dispersible acrylic resin (B) can be controlled to a desired value by adjusting the types and charging ratios of the monomers constituting the monomer composition used in the polymerization.

[0036] (Phosphoric acid compound (C)) The phosphoric acid compound (C) is contained in the aqueous surface treatment agent to improve the electrolytic solution resistance when laminating a metal. The phosphoric acid compound (C) is not particularly limited, and examples thereof include phosphoric acid, condensed phosphoric acid, phosphates, condensed phosphates, etc., and two or more kinds may be used in combination. Among these, phosphoric acid is preferable. Examples of the condensed phosphoric acid include pyrophosphoric acid, tripolyphosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid, ultraphosphoric acid, etc. Examples of the salt in the phosphate or condensed phosphate include alkali metal salts, ammonium salts, etc.

[0037] The ratio of the solid content mass of the phosphoric acid compound (C) to the total solid content of the aqueous metal surface treatment agent is preferably 5% or more and 40% or less as phosphoric acid ions. Thereby, the electrolytic solution resistance when laminating a metal can be improved. The content of the phosphoric acid compound (C) in the above aqueous surface treatment agent is more preferably 10% or more and 40% or less.

[0038] The concentration of the phosphoric acid compound (C) in the aqueous metal surface treatment agent is preferably 0.2% or more and 0.8% or less as phosphoric acid ions. Thereby, the electrolytic solution resistance when laminating a metal can be improved. The concentration of the phosphoric acid compound (C) in the above aqueous surface treatment agent is more preferably 0.2% or more and 0.5% or less.

[0039] (Nitrate ion (D)) Nitrate ion (D) is preferably contained in the aqueous metal surface treatment agent as a counter ion of trivalent chromium in the trivalent chromium compound (A). The inclusion of nitrate ion (D) and / or phosphate ion in the aqueous metal surface treatment agent can improve the corrosion resistance and adhesion of the formed film. For example, when using chromium(III) nitrate as the trivalent chromium compound (A), chromium(III) nitrate can be a source of nitrate ion (D). In addition to the above, a substance that can be a source of nitrate ion (D) may be blended in the aqueous surface treatment agent. Examples of such a substance include nitric acid. When using chromium(III) nitrate as the trivalent chromium compound (A), it is preferable that the source of nitrate ion (D) is only chromium(III) nitrate.

[0040] When the aqueous surface treatment agent according to this embodiment contains nitrate ion (D), the molar ratio (A / D) of the trivalent chromium compound (A) to nitrate ion (D) is preferably 0.3 or more and 0.4 or less. When the molar ratio (A / D) is less than 0.3, nitrate ions may be in excess and the adhesion may be poor. When the molar ratio (A / D) exceeds 0.4, nitrate ions, which are counter ions necessary to stabilize trivalent chromium, are insufficient, resulting in a lack of liquid stability and an increased likelihood of precipitation.

[0041] The concentration of nitrate ion (D) in the aqueous metal surface treatment agent is preferably 0.3% or more and 1.7% or less. This can ensure liquid stability and electrolytic solution resistance. The concentration of nitrate ion (D) in the above aqueous surface treatment agent is more preferably 0.5% or more and 1.6% or less.

[0042] The pH of the aqueous surface treatment agent of this embodiment is not particularly limited, but is, for example, 1 or more and 4 or less.

[0043] (Other components) The water content in the aqueous surface treatment agent of this embodiment is not particularly limited, but for example, it is 50% by mass or more and 99.9% by mass or less. Further, the aqueous surface treatment agent may further contain an organic solvent miscible with water as necessary to adjust the solid content concentration and drying rate. The organic solvent miscible with water is not particularly limited, but for example, ketone solvents such as acetone and methyl ethyl ketone; amide solvents such as N,N'-dimethylformamide and dimethylacetamide; alcohol solvents such as methanol, ethanol, isopropyl alcohol, and 1-methoxy-2-propanol; ether solvents such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether; pyrrolidone solvents such as 1-methyl-2-pyrrolidone and 1-ethyl-2-pyrrolidone, etc. can be mentioned.

[0044] The aqueous surface treatment agent of this embodiment may further contain known additives such as crosslinking agents, surface conditioners, antifoaming agents, plasticizers, antioxidants, antibacterial agents, and colorants as necessary.

[0045] [Surface-treated metal] By surface-treating a metal with the aqueous surface treatment agent of this embodiment, a surface-treated metal with a film formed on the surface can be obtained. The shape of the metal is not particularly limited, but for example, foil shape, plate shape, etc. can be mentioned. When using a foil-shaped or plate-shaped metal, one side may be surface-treated with the aqueous surface treatment agent of this embodiment, or both sides may be surface-treated with the aqueous surface treatment agent of this embodiment. Further, when surface-treating both sides with the aqueous surface treatment agent of this embodiment, both sides may be surface-treated with the same aqueous surface treatment agent, or both sides may be surface-treated with different aqueous surface treatment agents.

[0046] The surface-treated metal of this embodiment may be a metal having a film that is laminated. That is, a laminate film may be adhered to the film formed by surface-treating the metal. When using a foil-shaped or plate-shaped metal, the laminate film may be adhered to one side, or the laminate film may be adhered to both sides. Further, when the laminate film is adhered to both sides, the same laminate film may be adhered to both sides, or different laminate films may be adhered to both sides.

[0047] The material constituting the laminate film is not particularly limited. For example, polyethylene-based resins, polypropylene-based resins, polycarbonate-based resins, polyvinyl alcohol-based resins, polyvinyl acetal-based resins, polyvinylidene chloride-based resins, polyvinyl acetate-based resins, polyethylene terephthalate-based resins, polyethylene naphthalate-based resins, polybutylene terephthalate-based resins, polyethylene isophthalate-based resins, copolymerized polyester-based resins, polyester-based resins, polyamide-based resins, polyimide-based resins, polyetherimide-based resins, polyphenylene sulfide-based resins, fluorine-based resins, silicone-based resins, nylon-based resins, phenol-based resins, (meth)acrylic-based resins, epoxy-based resins, polymetaxylylene adipamide-based resins, etc. may be mentioned, and two or more kinds may be used in combination.

[0048] As the laminate film, a single-layer film or a multilayer film may be used. In the case of a multilayer film, a plurality of films may be laminated via an adhesive, or a plurality of films may be laminated without using an adhesive. The adhesive may be a one-component curable adhesive or a two-component curable adhesive. Examples of the resin component constituting the adhesive include polyester-based resins, polyether-based resins, polyurethane-based resins, epoxy-based resins, phenol-based resins, polyamide-based resins, polyolefin-based resins, polyvinyl acetate-based resins, cellulose-based resins, (meth)acrylic-based resins, polyimide-based resins, amino-based resins, rubbers, and silicone-based resins. The method for laminating a plurality of films without using an adhesive is not particularly limited, and examples thereof include coextrusion methods, sand lamination methods, thermal lamination methods, and the like.

[0049] The surface-treated metal of the present embodiment may have a layer other than the film and the laminate film (hereinafter referred to as "other layer"). The other layer may be present between the film and the laminate film, or may be present on the laminate film. Further, in the surface-treated metal of the present embodiment, the laminate film may not adhere to the metal having the film, and another layer may be present on the film.

[0050] The other layer is 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 decorative layer, a printing layer, a polarizing plate, a coloring layer, a liquid crystal layer, a light guide plate, a transparent conductive film, and a spacer, and two or more kinds thereof may be used in combination.

[0051] The adhesive layer may be formed of a one-component adhesive or a two-component adhesive.

[0052] Examples of the resin constituting the adhesive that can be used for forming the subsequent 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, ethylene-propylene fluoride copolymer resins, etc., and two or more of them may be used in combination. Examples of the combination of resins used in combination include, for example, 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, polyester resins and metal-modified polyolefin resins, etc.

[0053] Polyolefin resins include acid-modified polyolefin resins and metal-modified polyolefin resins. Examples of acid-modified polyolefin resins include polyolefin resins acid-modified with unsaturated carboxylic acids such as maleic anhydride-modified polypropylene and their anhydrides. Commercially available acid-modified polypropylene 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, Unistole (R-200X, R-303XE, E-200EM, A-200PM, A-201PM, H-100, H-200, XP01A, XP01B / 11B, XP03F, XP04A, etc.) manufactured by Mitsui Chemicals, Modic (P502, P512VB, P553A, P674V, P565, P555, P908H511, H503, H514, L502, L504, M142, M512, M522, M545, A543, F502, F573, F534A, etc.) manufactured by Mitsubishi Chemical, Arrow Base (SB-1200, SE-1200, SD-1200, DA1010, DC-1010, YA-6010, etc.) manufactured by Unitika, etc.

[0054] The method for forming the adhesive layer is not particularly limited, and examples thereof include an extrusion molding method and a dispersion method.

[0055] Examples of the uses of the surface-treated metal of the present embodiment include, for example, exterior materials for batteries, packaging materials for food, bodies or lids of food cans, bodies or lids of beverage cans, flexible packaging materials or surface protection materials containing metal foils such as aluminum pouches, separators for batteries, tab leads, capacitor cases, heat exchangers, electronic equipment 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 members, bicycle parts, vending machines, car body side plates of elevators, speed governors or hoisting machines, steps or interior panels of escalators, machine tools, injection molding machines, structural members or drive members of industrial robots, semiconductor manufacturing equipment, displays, submarines, signals, automatic looms, tunnel boring machines, pipelines, road signs, generators, garbage incinerators, exhaust gas treatment devices, motors, transformers, electronic circuits, electric bulbs, photomultiplier tubes, golf clubs, antennas, bolts, nuts, screws, etc. Among these, from the viewpoint of electrolyte resistance, exterior materials for batteries are preferable, and exterior materials for lithium-ion batteries are particularly preferable.

[0056] [Method for manufacturing metal foil laminate] The method for manufacturing a metal foil laminate according to the present embodiment includes a surface treatment step and a lamination step.

[0057] (Surface treatment step) The surface treatment step is, for example, a step of applying the aqueous surface treatment agent of the above embodiment to at least one surface of the prepared metal foil and then drying it.

[0058] The method for applying the aqueous surface treatment agent of the present embodiment is not particularly limited. For example, 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 can be mentioned.

[0059] The drying method is not particularly limited, and known methods can be used. For example, heating drying methods such as drying using an oven, drying by forced circulation of hot air, and drying by an electromagnetic induction heating furnace using an IH heater or the like can be mentioned. The conditions of the heating drying method 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 such as the air volume and air velocity set during heating drying can be arbitrarily set.

[0060] In the surface treatment step, it may be dried while applying the aqueous surface treatment agent of the present embodiment to the surface of the metal foil. For example, the aqueous surface treatment agent of the present embodiment may be applied to the surface of the preheated metal foil and dried.

[0061] The amount of the film formed after drying in the surface treatment step is preferably 0.1 mg / m 2 or more and 5000 mg / m 2 or less, and more preferably 1 mg / m 2 or more and 500 mg / m 2 or less.

[0062] (Lamination step) The lamination step is a step of laminating a film on the surface of the metal foil treated by the above surface treatment step. The method of lamination is not particularly limited, and known methods such as dry lamination method, heat lamination method, and extrusion lamination method can be used.

[0063] The manufacturing method of the metal foil laminate according to the present embodiment may include steps other than those described above, as long as the effects of the present invention are not inhibited.

Examples

[0064] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the examples.

[0065] [Preparation of Aqueous Metal Surface Treatment Agent] The aqueous metal surface treatment agents according to each example and comparative example were prepared by mixing with pure water so that each component had the amount shown in Table 1. (A) shown in Table 1 means a trivalent chromium compound (A), and the content means the mass ratio (% by mass) of trivalent chromium to the total solid content of the aqueous metal surface treatment agent. Similarly, (B) means a resin such as a water-soluble or water-dispersible acrylic resin (B), and the content means the mass ratio (% by mass) to the total solid content of the aqueous metal surface treatment agent. Similarly, (C) means a phosphoric acid compound (C), and the content means the mass ratio (% by mass) of the solid content as phosphate ions to the total solid content of the aqueous metal surface treatment agent. (A / D) means the molar ratio (A / D) of the trivalent chromium compound (A) to nitrate ions (D).

[0066] In each example and comparative example, a 35% chromium nitrate solution was used as the trivalent chromium compound (A). A 75% phosphoric acid aqueous solution was used as the phosphoric acid compound (C). In Comparative Example 9, nitric acid was further used as the source of nitrate ions (D).

[0067] Here, the definitions of the abbreviations in Table 1 are shown below. B1: Julimer AC-10L (manufactured by Toagosei Co., Ltd.) Polyacrylic acid Weight average molecular weight 50,000 Solid content acid value 779 mgKOH / g B2: Polyacrylic acid manufactured by Wako Pure Chemical Industries, Ltd. Weight average molecular weight 250,000 Solid content acid value 779 mgKOH / g B3: Julimer AC-10H (manufactured by Toagosei Co., Ltd.) Polyacrylic acid Weight average molecular weight 800,000 Solid content acid value 779 mgKOH / g B4: Julimer AC-10H (manufactured by Toagosei Co., Ltd.) Polyacrylic acid Weight average molecular weight 3,000,000 Solid content Acid value 779 mgKOH / g B5: Aron A-10SL (manufactured by Toagosei Co., Ltd.) Polyacrylic acid Weight average molecular weight 5,000 Solid content Acid value 779 mgKOH / g B6: Allic HL-415 (manufactured by Nippon Shokubai Co., Ltd.) Polyacrylic acid Weight average molecular weight 10,000 Solid content Acid value 779 mgKOH / g B7: Haricot G-51 (manufactured by Harima Chemicals, Inc.) Acrylamide B8: PVA-HC (manufactured by Kuraray Co., Ltd.) Polyvinyl alcohol B9: A-12SL (manufactured by Toagosei Co., Ltd.) Sulfonic acid copolymer B10: Addibond021 (manufactured by Solvay) Phosphonic acid-modified acrylic acid B11: K-30 (manufactured by Nippon Shokubai Co., Ltd.) Polyvinylpyrrolidone

[0068] [Coating of aqueous metal surface treatment agent (surface treatment)] The aqueous metal surface treatment agents according to the above-prepared respective examples and comparative examples were applied to an aluminum foil using a #0.8 nylon bar (bar coater). Then, baking was performed at 190 °C for 2 minutes.

[0069] [Dry lamination processing (lamination treatment)] XP01A (modified polyolefin, manufactured by Mitsui Chemicals, Inc.) and D-370N (isocyanate, manufactured by Mitsui Chemicals, Inc.) were mixed and stirred so that the mass ratio became 100:0.59 to prepare an adhesive solution. Next, the adhesive solution was applied to each sample coated with the above aqueous metal surface treatment agent using a #20 stainless steel bar (bar coater). Then, baking was performed at 100 °C for 60 seconds to form an adhesive layer. A CPP film was placed on the prepared sample, sandwiched with a PET film, and passed through a laminator for heat pressing. Then, it was aged at 60 °C for 3 days to obtain samples according to the respective examples and comparative examples.

[0070] [Evaluation] [Peel strength test (initial) (adhesion of laminated film)] Samples according to each example and comparative example were adjusted to a width of 15 mm, and a cut was made from the back with a cutter at a position about 1 cm below the film adhesion part, and the sample was bent. Next, the film at the bent part was pulled about 2 mm in the direction of the remaining part of the sample (180° direction), the seal strength (N / 15 mm) was measured, and the adhesion was evaluated. A tensile compression tester: LST-200N-S100 (manufactured by Minebea Mitsumi Inc.) was used for the test. The measurement was performed with n = 2, and the average value is shown in Table 1.

[0071] [Peeling Strength Test (Electrolyte Solution) (Electrolyte Resistance)] Deionized water was added to an electrolyte solution in which 1 M of LiPF6 was dissolved in a mixed solvent of ethylene carbonate / dimethyl carbonate / diethyl carbonate (volume ratio 1 / 1 / 1) at 10000 ppm to obtain a test electrolyte solution. After immersing the samples according to the above examples and comparative examples in the test electrolyte solution at 85 °C for 1 day, the peeling strength was measured in the same manner as above, and the electrolyte resistance was evaluated. Note that the film of the sample of Comparative Example 8 was completely peeled off, and the peeling strength could not be measured.

[0072] [Handling] Aqueous metal surface treatment agents according to each example and comparative example were prepared and allowed to stand at room temperature for one day, and the presence or absence of gelation and precipitation was visually confirmed. When neither gelation nor precipitation occurred, it was judged as acceptable, and when gelation or precipitation occurred, it was judged as unacceptable. The results are shown in Table 1 as acceptable (A) and unacceptable (B).

[0073]

Table 1

[0074] From the results shown in Table 1, it can be seen that when the metal plate is surface-treated with the aqueous surface treatment agent according to each example, the adhesion and electrolyte resistance of the laminate film of the laminated metal plate are higher than those when the metal plate is surface-treated with the aqueous surface treatment agent according to each comparative example. Note that the aqueous surface treatment agent according to Comparative Example 1 had high adhesion and electrolyte resistance of the laminate film, but had low handleability and was not practical.

Claims

1. An aqueous metal surface treatment agent for use in surface treatment of metals, comprising: The composition comprises a trivalent chromium compound (A), a water-soluble or water-dispersible acrylic resin (B), and a phosphoric acid compound (C), The water-soluble or water-dispersible acrylic resin (B) has a weight average molecular weight of 50,000 or more and 1,000,000 or less and an acid value of the solid content of more than 740 mgKOH / g.

2. a mass ratio of trivalent chromium contained in the trivalent chromium compound (A) to a total solid content of the aqueous metal surface treatment agent is 5% or more and 15% or less, calculated as trivalent chromium; 2. The aqueous metal surface treatment agent according to claim 1, wherein the ratio of the solid content mass of the phosphate compound (C) to the total solid content mass of the aqueous metal surface treatment agent is 5% or more and 40% or less in terms of phosphate ions.

3. The aqueous metal surface treatment agent further contains nitrate ions (D), 3. The aqueous metal surface treatment agent according to claim 1, wherein a molar ratio (A / D) of the trivalent chromium compound (A) to the nitrate ions (D) is 0.3 or more and 0.4 or less.

4. A method for producing a metal foil laminate, comprising the steps of: a surface treatment step of treating at least one surface of the metal foil; A lamination step of laminating a film on the surface of the metal foil treated by the surface treatment step, the aqueous metal surface treatment agent used in the surface treatment step comprises a trivalent chromium compound (A), a water-soluble or water-dispersible acrylic resin (B), and a phosphoric acid compound (C); The water-soluble or water-dispersible acrylic resin (B) has a weight average molecular weight of 50,000 or more and 1,000,000 or less and an acid value of the solid content of more than 740 mgKOH / g.

5. a mass ratio of trivalent chromium contained in the trivalent chromium compound (A) to a total solid content of the aqueous metal surface treatment agent is 5% or more and 15% or less, calculated as trivalent chromium; 5. The method for producing a metal foil laminate according to claim 4, wherein a ratio of a solid content mass of the phosphate compound (C) to a total solid content mass of the aqueous metal surface treatment agent is 5% or more and 10% or less in terms of phosphate ions.

6. The aqueous metal surface treatment agent further contains nitrate ions (D), 6. The method for producing a metal foil laminate according to claim 4, wherein a molar ratio (A / D) of the trivalent chromium compound (A) to the nitrate ions (D) is 0.3 or more and 0.4 or less.

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