Aqueous surface treatment agent and surface-treated metal

Abstract

Provided is an aqueous surface treatment agent capable of improving electrolyte solution resistance when a surface-treated metal is used as a tab for a secondary battery or an outer packaging material for a battery by being used in surface treatment of the metal. An aqueous surface treatment agent for treating the surface of a metal, the aqueous surface treatment agent comprising a cerium oxide sol (A), an organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group, and an oxazoline group-containing resin (C).

Description

Technical Field

[0001] The invention relates to a water-based surface treatment agent and a surface-treated metal. Background Art

[0002] The metal plate used in the tab lead for secondary batteries is subjected to surface treatment in order to prevent the insulating seal structure of the tab from peeling off due to the electrolyte. In addition, in the laminated outer packaging material for secondary batteries, surface treatment is also applied in order to prevent the metal foil and laminated film from peeling off due to the electrolyte. In such surface treatment of metals, an aqueous surface treatment agent is used.

[0003] For example, Patent Document 1 describes a lithium battery packaging material, which is characterized in that, in the lithium battery packaging material, an adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer, and a sealant layer are stacked in sequence on one surface of a substrate layer, and the coating layer is a layer (A) formed by mixing 1 to 100 parts by mass of phosphoric acid or a phosphate with respect to 100 parts by mass of a rare earth element oxide.

[0004] Patent document 2 describes an outer packaging material for a lithium ion battery, characterized in that, in the outer packaging material for a lithium ion battery, an adhesive layer, an aluminum foil layer, a coating layer, an adhesive resin layer, and a sealant layer are sequentially stacked on one surface of a substrate layer, wherein the coating layer is a layer comprising an anionic polymer (A), a cross-linking agent (B) for cross-linking the anionic polymer (A), a phosphorus compound (C), and a rare earth element oxide (D), and wherein the ratio W1 / W2 of the total content W1 (mass %) of the anionic polymer (A) and the cross-linking agent (B) to the total content W2 (mass %) of the phosphorus compound (C) and the rare earth element oxide (D) is less than 1.

[0005] Patent document 3 describes an outer packaging material for lithium ion batteries, which is composed of the following laminate, wherein an adhesive layer, a base treatment layer, an aluminum foil layer, an anti-corrosion treatment layer, an adhesive resin layer and a sealant layer are sequentially stacked on one surface of a substrate layer, wherein the base treatment layer comprises the following component (A), the following component (B) and the following component (C), and the total amount of the component (B) and the component (C) relative to 100 parts by mass of the component (A) is 200 to 12,000 parts by mass. (A) A cross-linked resin formed by a resin (A1) having two or more nitrogen-containing functional groups and a resin (A2) having a reactive functional group that reacts with the aforementioned nitrogen-containing functional group; (B) a rare earth element oxide; (C) phosphoric acid or a phosphate.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2008-210777

[0009] Patent Document 2: Japanese Patent Application Publication No. 2011-065834

[0010] Patent Document 3: International Publication No. 2014 / 181862 Summary of the invention

[0011] Problems to be solved by the invention

[0012] Here, in the surface treatment of metals, when the surface treated metal is used for secondary battery tabs or battery outer packaging materials, there is a problem that electrolyte resistance needs to be improved in order to maintain excellent adhesion with insulating sealing structures and laminate films even in an environment contacting electrolyte.

[0013] Therefore, an object of the present invention is to provide an aqueous surface treatment agent which can improve the electrolyte resistance of the surface treated metal when the surface treated metal is used as a secondary battery tab or a battery outer casing material by being used for the surface treatment of the metal.

[0014] Means used to solve problems

[0015] The aqueous surface treatment agent of the present invention is an aqueous surface treatment agent for surface treatment of metals, which comprises: Cerium oxide sol (A); an organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group; and Oxazoline group-containing resin (C).

[0016] In one embodiment of the aqueous surface treatment agent of the present invention, it is preferred that 50% or more of the solid content by mass of the resin component of the aqueous surface treatment agent is the oxazoline group-containing resin (C).

[0017] In one embodiment of the aqueous surface treatment agent of the present invention, the organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group preferably has a total of two or more phosphonic acid groups and / or phosphoric acid groups in one molecule.

[0018] In one embodiment of the aqueous surface treatment agent of the present invention, it is more preferred that the organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group is phytic acid or a salt thereof.

[0019] The surface-treated metal of the present invention is a surface-treated metal having a film formed by surface-treating the metal using the above-mentioned aqueous surface-treating agent.

[0020] In one embodiment of the surface-treated metal of the present invention, the metal is preferably aluminum or an aluminum alloy or copper or a copper alloy.

[0021] In one embodiment of the surface-treated metal of the present invention, the metal is preferably plated.

[0022] In one embodiment of the surface-treated metal of the present invention, it is preferred that a polyolefin-based resin film layer is provided on the film of the metal having the film.

[0023] In one embodiment, the surface-treated metal of the present invention may be a tab for a secondary battery.

[0024] In one embodiment of the surface-treated metal of the present invention, the metal having the film is preferably subjected to lamination.

[0025] In one embodiment, the surface-treated metal of the present invention may be an outer packaging material for a battery.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to provide an aqueous surface treatment agent which can improve the electrolyte resistance of the surface treated metal when the surface treated metal is used as a secondary battery tab or a battery outer casing material by being used for the surface treatment of the metal. DETAILED DESCRIPTION

[0028] The following describes embodiments of the present invention, but the purpose of these descriptions is to illustrate the present invention and not to limit the present invention in any way.

[0029] In the present invention, two or more embodiments may be arbitrarily combined.

[0030] In the present invention, the term "film" and "coating film" may be used interchangeably.

[0031] In the present invention, the term "solid content" is a concept that includes solid components, non-volatile components, and effective components.

[0032] In this specification, unless otherwise specified, a numerical range includes the upper limit and the lower limit of the range. For example, 0.01 to 3 mass % means a range of 0.01 mass % or more and 3 mass % or less.

[0033] (Water-based surface treatment agent)

[0034] The aqueous surface treatment agent of the present invention is an aqueous surface treatment agent for surface treatment of metals, which comprises: Cerium oxide sol (A); an organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group; and Oxazoline group-containing resin (C).

[0035] In addition, the aqueous surface treatment agent of the present invention may further include other resins (D). In addition, the aqueous surface treatment agent of the present invention may generally include water. In addition, the aqueous surface treatment agent of the present invention may further include known additives such as a crosslinking agent, a surface conditioner, a defoamer, a plasticizer, an antioxidant, an antibacterial agent, a colorant, etc. In addition, the aqueous surface treatment agent of the present invention may further include an acid or a base for adjusting pH.

[0036] Next, each component of the aqueous surface treatment agent of the present invention will be described.

[0037] ・Cerium oxide sol (A)

[0038] The cerium oxide sol (A) is a sol (colloid) in which cerium oxide (CeO 2 ) is dispersed in a liquid dispersion medium (sometimes referred to as a “solvent”) at normal temperature and pressure.

[0039] The average particle diameter of cerium oxide may be preferably 1 nm or more, more preferably 3 nm or more, and may be preferably 500 nm or less, more preferably 50 nm or less.

[0040] Examples of the dispersant for cerium oxide include water, organic acids, and phosphoric acid-based dispersants.

[0041] The pH of the cerium oxide sol (A) is preferably 2-10.

[0042] The cerium oxide content (concentration) of the cerium oxide sol (A) is preferably 1 wt % to 50 wt %.

[0043] The cerium oxide sol (A) may be used alone or in combination of two or more.

[0044] Commercially available products of the cerium oxide sol (A) include, for example, “NEEDLAL B-10” (manufactured by Taki Chemical Co., Ltd.), “NEEDLAL P-10” (manufactured by Taki Chemical Co., Ltd.), “NEEDLAL U-15” (manufactured by Taki Chemical Co., Ltd.), “CESL-15N” (manufactured by Dai-ichi Kizenso Chemical Industry Co., Ltd.), and “CESL-30N” (manufactured by Dai-ichi Kizenso Chemical Industry Co., Ltd.).

[0045] The average particle size of the cerium oxide sol (A) of the present invention is a median particle size (D 50 ). Specifically, it can be measured using a dynamic light scattering photometer (DLS-8000 series) manufactured by Otsuka Electronics Co., Ltd. or the like.

[0046] When the aqueous surface treatment agent of the present invention contains cerium oxide sol (A), the cerium oxide sol (A) does not dissolve in the electrolyte, thereby improving electrolyte resistance. On the other hand, water-soluble cerium compounds are easily dissolved in the electrolyte and cannot meet the desired electrolyte resistance.

[0047] As an organophosphorus compound (B) having a phosphonic acid group and / or a phosphate group, there can be cited: hydroxyethylidene diphosphonic acid (HEDP), nitrilo tris (methylene phosphonic acid) (NTMP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), ethylenediamine tetramethylenephosphonic acid (EDTMP), phenylphosphonic acid, octylphosphonic acid and other organophosphorus compounds having a phosphonic acid group, phytic acid, O-phosphoethanolamine, phosphoserine, glycerophosphoric acid and other organophosphorus compounds having a phosphate group, and their salts. These organophosphorus compounds can also be used in combination. In order to improve electrolyte resistance, the organophosphorus compound (B) having a phosphonic acid group and / or a phosphate group is preferably an organophosphorus compound having a total of two or more phosphonic acid groups and / or phosphate groups in one molecule, more preferably phytic acid or its salt.

[0048] The aqueous surface treatment agent of the present invention can improve the electrolyte resistance by containing an organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group, so that the metal of the substrate and the cerium oxide sol (A) can be cross-linked and the cerium oxide sols (A) can be cross-linked with each other. On the other hand, inorganic phosphoric acid compounds are easily hydrolyzed and the cross-links are cut in the electrolyte, so the desired electrolyte resistance cannot be achieved.

[0049] From the perspective of improving electrolyte resistance, the solid content mass ratio ((A) / (B)) of the cerium oxide sol (A) in the aqueous surface treatment agent to the organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group can be preferably greater than 1, more preferably greater than 2.5, and can be preferably less than 50, more preferably less than 40.

[0050] ・Oxazoline-containing resin (C)

[0051] As the resin (C) containing oxazoline groups, it is not particularly limited as long as it is a resin having oxazoline groups. As long as the resin (C) containing oxazoline groups is a resin having oxazoline groups as side chains on the main chain with any skeleton structure, for example, resins containing oxazoline groups whose main chains are acrylic skeletons, resins containing oxazoline groups whose main chains are styrene / acrylic skeletons, resins containing oxazoline groups whose main chains are styrene skeletons, and resins containing oxazoline groups whose main chains are acrylonitrile / styrene skeletons, etc. can be cited. Among them, from the viewpoint of excellent stability in aqueous solvents and the appearance after coating being colorless and transparent, resins containing oxazoline groups whose main chains are acrylic skeletons are preferred. For example, as resins containing oxazoline groups whose main chains are acrylic skeletons, "EPOCROS WS series" (trade name, made by Nippon Catalyst) can be cited. The oxazoline value of the resin containing oxazoline groups is preferably 120 to 240 g (solid content) / equivalent. The number average molecular weight of the oxazoline group-containing resin is preferably 10000 to 50000. The number average molecular weight is determined by a GPC method using polystyrene as a standard.

[0052] The aqueous surface treatment agent of the present invention, when containing an oxazoline group-containing resin (C), reacts the oxazoline group-containing resin with a carboxylic acid group, carboxylic anhydride, aromatic thiol group, phenol group, etc. contained in an insulating sealing structure, a laminate film or an adhesive layer to form a bond, thereby improving electrolyte resistance.

[0053] From the viewpoint of improving electrolyte resistance, the solid content mass ratio ((A) / (C)) of the cerium oxide sol (A) in the aqueous surface treatment agent to the oxazoline-containing resin (C) can be preferably greater than 0.5, more preferably greater than 1, and can be preferably less than 50, more preferably less than 40.

[0054] ・Other resins (D)

[0055] The water-based surface treatment agent of the present invention may further include other resins (D) (i.e., resins other than the oxazoline-containing resin (C)). Examples of other resins (D) include acrylic resins, polyester resins, alkyd resins, epoxy resins, polyurethane resins, phenolic resins, and melamine resins. Other resins (D) may be used alone or in combination of two or more.

[0056] In order to improve electrolyte resistance, the mass of the oxazoline group-containing resin (C) accounts for preferably 50% or more, more preferably 70% or more, and even more preferably 90% or more of the solid mass of the resin component of the aqueous surface treatment agent.

[0057] ・Other ingredients and various characteristics of water-based surface treatment agents

[0058] The aqueous surface treatment agent of the present invention may generally contain water. The content of water in the aqueous surface treatment agent is not particularly limited, and is, for example, 50% by mass or more and 99.9% by mass or less.

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

[0060] The pH of the aqueous surface treatment agent of the present invention is preferably 2 or more and 12 or less, and more preferably 3 or more and 10 or less. When the pH of the aqueous surface treatment agent of the present invention is 2 or more and 12 or less, the storage stability of the aqueous surface treatment agent is improved.

[0061] In order to adjust the pH, the aqueous surface treatment agent of the present embodiment may further contain an acid or a base as required. The acid is not particularly limited, and examples thereof include: inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, pyrophosphoric acid, metaphosphoric acid, and hydrofluoric acid; organic acids such as acetic acid, trifluoroacetic acid, and benzoic acid. The base is not particularly limited, and examples thereof include: inorganic bases such as ammonia, sodium hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; organic bases such as trimethylamine, diethylamine, and triethylamine.

[0062] In order to adjust the solid content concentration and drying speed, the water-based surface treatment agent of the present invention may also contain an organic solvent mixed with water as needed. The organic solvent mixed with water is not particularly limited, and examples thereof include: ketone solvents such as acetone and methyl ethyl ketone; amide solvents such as N,N'-dimethylformamide and dimethylacetamide; alcohol solvents such as methanol, ethanol, isopropanol, 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.

[0063] ・Method for producing water-based surface treatment agent

[0064] The method for producing the aqueous surface treatment agent of the present invention is not particularly limited, and the aqueous surface treatment agent can be produced by a known method such as mixing the above-mentioned components (A) to (C) and other components added as necessary with water as a solvent and stirring the mixture.

[0065] ・Surface treated metal

[0066] The aqueous surface treatment agent of the present invention can be used to form a surface-treated metal. The surface-treated metal of the present invention has a film formed by surface-treating a metal using the aqueous surface treatment agent described above.

[0067] ·Metal

[0068] There is no particular limitation on the metal, for example, iron, zinc, aluminum, copper, nickel, etc. can be cited, and two or more can be used in combination. That is, the metal can be an alloy. As an alloy component, for example, carbon, nitrogen, oxygen, phosphorus, sulfur, silicon, manganese, chromium, titanium, molybdenum, etc. can be included. Among these, from the viewpoint of conductivity, processability and adhesion, preferably aluminum or aluminum alloy, iron or iron alloy or copper or copper alloy, more preferably aluminum or aluminum alloy or copper or copper alloy, further preferably aluminum or aluminum alloy. As aluminum alloy, for example, Al-Cu alloy, Al-Mn alloy, Al-Si alloy, Al-Mg alloy, Al-Mg-Si alloy, Al-Zn-Mg alloy, aluminum die casting (ADC material) and the like can be cited. In the case where the surface treated metal of the present invention is used as a battery outer packaging material or a positive electrode tab for a secondary battery (especially a laminated battery such as a laminated lithium ion secondary battery), as an aluminum alloy, preferably A1050 material, A1N30 material, A8021 material, A8079 material and the like are used. As iron alloys, for example, cold rolled steel sheets such as SPCC, SPCD, and SPCE, stainless steel (SUS), etc. can be cited. As SUS, for example, austenitic stainless steels such as SUS304, SUS301, and SUS316, ferritic stainless steels such as SUS430, and martensitic stainless steels such as SUS410 can be cited. As zinc alloys, for example, Zn-Al alloys can be cited. As copper alloys, for example, brass can be cited. As nickel alloys, for example, Ni-P alloys can be cited.

[0069] The shape of the metal is not particularly limited, and for example, a foil or plate shape can be cited. When a foil or plate-shaped metal is used, the surface treatment can be applied to only one side using an aqueous surface treatment agent, or to both sides using an aqueous surface treatment agent. In addition, when the surface treatment is applied to both sides, the surface treatment can be applied to both sides using a single aqueous surface treatment agent, or the surface treatment can be applied to each single side using an aqueous surface treatment agent of a different composition.

[0070] The metal may be subjected to a plating treatment. As the type of plating, for example, metals such as nickel, zinc, chromium, iron, tin, copper, silver, platinum, gold, etc. may be cited, and two or more metals may be used in combination. As the plating method, for example, electroplating, electroless plating (chemical plating), hot dip plating, vacuum evaporation, sputtering, ion plating, etc. may be cited. In the case where the surface-treated metal of the present invention is used as a negative electrode tab, it is desirable to use nickel-plated copper or the like as the metal subjected to the plating treatment.

[0071] For the surface treated metal of the present invention, the metal with the coating may be subjected to lamination. That is, a laminated film may be bonded to the metal with the coating. In the case of using a foil-shaped or plate-shaped metal with a coating, the laminated film may be bonded only on one side or on both sides. In addition, in the case of bonding laminated films on both sides, the same type of laminated film may be bonded on both sides, or different types of laminated films may be bonded on each single side.

[0072] As the material constituting the laminated film and the insulating sealing structure, there is no particular limitation, and for example, 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, copolyester resins, polyester resins, polyamide resins, polyimide resins, polyetherimide resins, polyphenylene sulfide resins, fluorine resins, silicone resins, nylon resins, phenolic resins, (meth) acrylic resins, epoxy resins, poly(m-xylene adipamide) resins, etc. can be cited. One of these materials can be used alone, or two or more can be used in combination.

[0073] The laminated film and the insulating sealing structure may be uniaxially stretched or biaxially stretched.

[0074] The laminated film and the insulating sealing structure can be a single-layer film or a multilayer film formed by stacking multiple (multiple) films. In the case of stacking multiple films, the films can be stacked via an adhesive or directly stacked without an adhesive. The adhesive can be a single-component curing adhesive or a two-component curing adhesive. As the resin component constituting the adhesive, 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 can be cited. As a method for directly stacking multiple films without an adhesive, for example, methods of bonding in a hot melt state such as coextrusion, sandwich lamination, and hot lamination can be cited.

[0075] The surface-treated metal of the present invention can be hot-pressed and bonded with a laminated film or an insulating sealing structure. In the case of hot-pressing and bonding a laminated film or an insulating sealing structure to a surface-treated metal, the material of the surface of the laminated film or the insulating sealing structure that contacts the surface-treated metal is preferably a polyolefin resin. As polyolefin resins, for example, low-density, medium-density, high-density polyethylene, polypropylene, polybutene and other polyolefin resins, acid-modified polyolefin resins obtained by grafting and modifying these polyolefin resins using maleic anhydride and the like, and the like can be cited. These polyolefin resins can be used alone or in combination of two or more. Among these, acid-modified polyolefin resins obtained by grafting and modifying polyolefin resins with maleic anhydride and the like are preferred.

[0076] The laminated film and insulating sealing structure may be a single-layer film formed of a polyolefin resin such as an acid-modified polyolefin resin, or a film in which a heat-resistant resin such as polyethylene terephthalate or polyethylene naphthalate is laminated on a polyolefin resin such as an acid-modified polyolefin resin.

[0077] The surface treated metal of the present invention may have a layer (other layer) other than the film, the laminated film and the insulating sealing structure. The other layer may be arranged between the film and the laminated film or between the film and the insulating sealing structure, or may be arranged on the laminated film or the insulating sealing structure. In addition, the other layer may be arranged on the film without using the laminated film or the insulating sealing structure.

[0078] As other layers, there are no particular limitations, and examples thereof include known layers such as an adhesive layer, a coating film, a hard coating layer, an antifouling layer, an antiglare layer, a design layer, a printed layer, a polarizing plate, a coloring layer, a liquid crystal layer, a light guide plate, a transparent conductive film, and a spacer. Other layers may be used alone or in combination of two or more.

[0079] The adhesive layer may be formed of a one-component adhesive or a two-component adhesive.

[0080] As the resin component constituting the adhesive that can be used to form the adhesive layer, polyolefin resin, polyester resin, polyether resin, polyurethane resin, polycarbonate resin, epoxy resin, phenolic resin, polyamide resin, polyvinyl acetate resin, cellulose resin, (methyl) acrylic resin, polyimide resin, amino resin, chloroprene rubber resin, nitrile rubber resin, styrene-butadiene rubber resin, silicone resin, fluoroethylene-propylene copolymer resin, etc. can be enumerated. These resin components can be used alone or in combination of two or more. As the combination of two or more adhesives, for example, polyurethane resin and modified polyolefin resin, polyamide resin and acid-modified polyolefin resin, polyamide resin and metal-modified polyolefin resin, polyamide resin and polyester resin, polyester resin and acid-modified polyolefin resin, polyester resin and metal-modified polyolefin resin, etc. can be enumerated.

[0081] The polyolefin resin used as the resin component constituting the adhesive that can be used to form the adhesive layer includes acid-modified polyolefin resins and metal-modified polyolefin resins. As the acid-modified polyolefin resin, for example, polyolefin resins acid-modified with unsaturated carboxylic acids or their anhydrides, such as maleic anhydride-modified polypropylene, can be cited. Examples of commercially available acid-modified polypropylene resins include ADMER manufactured by Mitsui Chemicals, Inc. (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.), UNISTOLE manufactured by Mitsui Chemicals, Inc. (R-200X, R-303XE, E-200EM, A-200PM, A-201PM, H-100, H-200, XP01A, XP01B / 11B, XP03F, XP04A, etc.), MODIC manufactured by Mitsubishi Chemical Corporation (P502, P512VB, P553A, P674V, P565, P555, P908H511, H503, H514, L502, L504, M142, M512, M522, M545, A543, F502, F573, F534A, etc.), ARROWBASE manufactured by UNITIKA Corporation (SB-1200, SE-1200, SD-1200, DA1010, DC-1010, YA-6010, etc.), etc.

[0082] The method for forming the adhesive layer is not particularly limited, and examples thereof include an extrusion molding method and a dispersion method.

[0083] ・Surface treatment

[0084] The surface treatment method includes a film forming step of performing surface treatment on a metal using the aqueous surface treatment agent of the present invention to form a film.

[0085] In the film forming step, for example, the aqueous surface treating agent of the present invention is applied to the surface of the metal and then dried.

[0086] The method for applying the aqueous surface treatment agent of the present invention 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 knife coater coating, air knife coater coating, curtain coating, spin coating, brush coating, roll coating, rod coater coating, dip coating, applicator coating, spray coating, flow coating, and combinations thereof.

[0087] The drying method is not particularly limited, and a known method can be used, for example, a method of drying using an oven, a method of drying by forced circulation of hot air, a method of drying by an electromagnetic induction heating furnace using an IH heater, etc., and other heating drying methods can be cited. The conditions of the heating drying method can be set, for example, at a temperature of 40°C or more and 230°C or less for 2 seconds or more and 180 seconds or less. Here, the conditions such as the air volume and wind speed set during heating drying can be set arbitrarily.

[0088] In the film forming step, the aqueous surface treatment agent of the present invention may be applied to the surface of the metal and then dried. For example, the aqueous surface treatment agent of the present invention may be applied to the surface of the preheated metal and then dried.

[0089] The amount of the film formed after drying in the film forming step is preferably 0.1 mg / m 2 Above and 5000mg / m 2 Below, more preferably 10 mg / m 2 Above and 1000mg / m 2 the following.

[0090] The surface treatment method may further include a lamination step of laminating the metal having the coating.

[0091] The method for laminating the metal having a coating is not particularly limited, and for example, a known method such as dry lamination, wet lamination, heat lamination, extrusion lamination, etc. can be used.

[0092] Example

[0093] The present invention will be described in more detail below with reference to Examples. However, these Examples are intended to illustrate the present invention and are not intended to limit the present invention in any way.

[0094] The materials of the aqueous surface treatment agent used in the examples are as follows.

[0095] ・Component A: Cerium compound material

[0096] Component A1: Cerium oxide sol (manufactured by Taki Chemical Co., Ltd., trade name "NEEDLAL B-10", CeO2 content 10%, particle size D 50 8nm, dispersant is organic acid, pH 8)

[0097] Component A2: Cerium oxide sol (manufactured by Taki Chemical Co., Ltd., trade name "NEEDLAL P-10", CeO2 content 10%, particle size D 50 8nm, dispersant is phosphoric acid, pH7)

[0098] Component A3: Cerium oxide sol (manufactured by Daiichi Rare Element Chemical Co., Ltd., trade name "CESL-30N", concentration 30.0-31.0 wt%, specific gravity 1.35-1.45, particle size D 50 5~15nm, solvent is water, pH2.0~3.0)

[0099] Ingredient A4: Cerium (III) chloride

[0100] Ingredient A5: Cerium (IV) ammonium nitrate

[0101] Components A1 to A3 belong to the cerium oxide sol (A).

[0102] ・Component B: Phosphorus compound

[0103] Component B1: Hydroxyethylidene diphosphonic acid (HEDP, manufactured by CHELEST Co., Ltd., the number of phosphonic acid groups / phosphoric acid groups is 2)

[0104] Component B2: 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC, manufactured by Chelast Corporation, the number of phosphonic acid groups / phosphoric acid groups is 1)

[0105] Component B3: nitrilotris(methylenephosphonic acid) (NTMP, manufactured by CHELEST Co., Ltd., the number of phosphonic acid groups / phosphoric acid groups is 3)

[0106] Component B4: ethylenediaminetetramethylenephosphonic acid (EDTMP, manufactured by CHELEST Co., Ltd., the number of phosphonic acid groups / phosphoric acid groups is 4)

[0107] Ingredient B5: Phytic acid (the number of phosphonic acid groups / phosphoric acid groups is 6)

[0108] Ingredient B6: Phosphoric acid

[0109] Ingredient B7: Sodium tripolyphosphate

[0110] Ingredient B8: Potassium tripolyphosphate

[0111] Components B1 to B5 are organic phosphorus compounds (B) having a phosphonic acid group and / or a phosphoric acid group.

[0112] ・Component C: Oxazoline group-containing resin (C)

[0113] Component C1: water-soluble polymer containing oxazoline groups (manufactured by Nippon Shokubai Co., Ltd., trade name "EPOCROSWS-300", the polymer main chain is acrylic acid, oxazoline equivalent (WPO) is 130g solid / equivalent (theoretical value), oxazoline group content is 7.7mmol / g solid (theoretical value), glass transition temperature Tg is 90°C (calculated value), number average molecular weight Mn is 4×10 4 , the weight average molecular weight Mw is 12×10 4 , non-volatile content is 10wt%, solvent is water, pH 7~10)

[0114] Component C2: water-soluble polymer containing oxazoline groups (manufactured by Nippon Shokubai Co., Ltd., trade name "EPOCROSWS-500", the polymer main chain is acrylic acid, oxazoline equivalent (WPO) is 220g solid / equivalent (theoretical value), oxazoline group content is 4.5mmol / g solid (theoretical value), glass transition temperature Tg is 50°C (measured value), number average molecular weight Mn is 2×10 4 , the weight average molecular weight Mw is 7×10 4 , non-volatile content is 39wt%, solvent is water / 1-methoxy-2-propanol, pH 8-10)

[0115] Component C3: water-soluble polymer containing oxazoline groups (manufactured by Nippon Shokubai Co., Ltd., trade name "EPOCROSWS-700", the polymer main chain is acrylic acid, oxazoline equivalent (WPO) is 220g solid / equivalent (theoretical value), oxazoline group content is 4.5mmol / g solid (theoretical value), glass transition temperature Tg is 50°C (measured value), number average molecular weight Mn is 2×10 4 , the weight average molecular weight Mw is 4×10 4 , non-volatile content 25wt%, solvent is water, pH 7~10)

[0116] ・Component D: Other resin (D)

[0117] Component D1: ammonium polyacrylate (manufactured by Toagosei Co., Ltd., trade name "ARON A-30SL")

[0118] Component D2: Aminated phenolic resin (manufactured by Maruzen Petrochemical Co., Ltd., trade name "MARUKA LINKERMAM")

[0119] Component D3: Carbonyl-containing polyvinyl alcohol (manufactured by VAM & POVAL, trade name "DF-17")

[0120] Component D4: polyallylamine (manufactured by NITTOBO MEDICAL Co., Ltd., trade name "PAA-15C")

[0121] ・Examples 1 to 27 and Comparative Examples 1 to 11

[0122] ・Preparation of water-based surface treatment agents

[0123] Each component and water were mixed in the formulation shown in Table 1 to prepare a water-based surface treatment agent.

[0124] [Table 1]

[0125] ・Production and evaluation of evaluation samples

[0126] ・Primary rust prevention treatment (film formation)

[0127] <Positive and negative electrode tabs>

[0128] The metal plate is subjected to surface treatment using the aqueous surface treatment agent prepared above, thereby forming a film. As a specific step of surface treatment, first, a 1% by mass dilution of SURF CLEANER EC374 (manufactured by NIPPON PAINT SURF CHEMICALS) is used to degrease the metal plate (metal terminal) at 65 ° C for 3 seconds. Then, the aqueous surface treatment agent prepared above is applied by gravure coating, and dried at 200 ° C for 30 seconds to form a surface treatment film. As a metal terminal, an aluminum plate (A1050 material) with a width of 20 mm, a length of 50 mm, and a thickness of 0.4 mm is used as a positive electrode tab, and a NiCu plate with a width of 20 mm, a length of 50 mm, and a thickness of 0.4 mm is used as a negative electrode tab. Then, the metal terminal formed with a surface treatment film is clamped between a pair of resin films. It is arranged between heat sealing rods, and the metal terminal formed with a surface treatment film and the pressurized heat welding of the resin film are performed to make an electrode terminal. As the resin film, a monolayer film (width 10 mm, length 40 mm, thickness 80 μm) of maleic anhydride-modified polyolefin resin obtained by grafting maleic anhydride on polyolefin resin was used. For the pressurized heat fusion conditions, the gap between the heat sealing bars was set to 210 μm, the temperature was set to 200°C, and the thrust of the heat sealing bar was set to 400N.

[0129] <Laminated materials>

[0130] A 40 μm thick Al foil (A8021 material) was degreased at 65°C for 3 seconds using a 1% by mass dilution of SURF CLEANER EC374 (manufactured by NIPPON PAINT SURF CHEMICALS). Next, the aqueous surface treatment agent prepared above was applied using a bar coater (#6), and then dried for 2 minutes at a raw material temperature of 190°C or higher using a hot air oven to form a surface treatment film.

[0131] Next, the metal plate with the film formed thereon was subjected to lamination. Specifically, a maleic anhydride-modified polypropylene dispersion as an adhesive was applied in an amount of 3 g / m 2 The polypropylene film was then applied to the film formed on the surface of the metal plate and dried to form an adhesive layer. The polypropylene film was then heat-pressed and bonded to the metal plate with the adhesive layer at 190°C and 0.38MPa. The laminated Al foil was cut into a size of 150 mm × 15 mm.

[0132] ・Initial adhesion

[0133] The peel strength when the polypropylene film is peeled off from the Al foil of the laminated Al foil test piece at a peeling speed of 50 mm / min and an angle of 180 degrees was measured using a desktop precision universal testing machine Autograph AGS-5KNX (manufactured by Shimadzu Corporation), and this value was set as the "initial peel strength". In addition, in the case of the positive electrode tab or the negative electrode tab, the peel strength when the maleic anhydride-modified polyolefin resin film is peeled off from the metal terminal is measured by the same method, and this value is set as the "initial peel strength".

[0134] ・Evaluation of electrolyte resistance

[0135] 1000 ppm of ion exchange water was added to an electrolyte solution LBG-00015 (manufactured by Kishida Chemical Co., Ltd.) in which 1 M LiPF6 was dissolved in a mixed solvent of ethylene carbonate / dimethyl carbonate / diethyl carbonate (volume ratio 1 / 1 / 1) to obtain a test electrolyte solution.

[0136] After the test piece was immersed in the test electrolyte at 85°C for 14 days, the peel strength was measured in the same manner as above to evaluate the electrolyte resistance. This value was defined as the "peel strength after electrolyte immersion".

[0137] The ratio of "peel strength after electrolyte immersion" to "initial peel strength" is set as the peel strength retention rate, which is used as an indicator of electrolyte resistance. The higher the value of the peel strength retention rate, the higher the electrolyte resistance can be evaluated (good). For the positive electrode tab, the negative electrode tab, and the laminated Al foil, the electrolyte resistance is evaluated according to the following evaluation criteria.

[0138] 5: Peel strength retention rate is more than 80%

[0139] 4: Peel strength retention rate is more than 60% and less than 80%

[0140] 3: Peel strength retention rate is more than 40% and less than 60%

[0141] 2: Peel strength retention rate is more than 20% and less than 40%

[0142] 1: Peel strength retention rate is less than 20% or peeling

[0143] Table 2 shows the evaluation results.

[0144] [Table 2]

[0145] As can be seen from Table 2, when the metal plates were surface treated with the aqueous surface treatment agents of Examples 1 to 27, the positive electrode tabs, the negative electrode tabs, and the laminated materials had high electrolyte resistance.

[0146] In contrast, the aqueous surface treatment agents of Comparative Examples 1 to 3 do not contain an oxazoline-containing resin (C), an organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group, and a cerium oxide sol (A), respectively, so the positive electrode tab, the negative electrode tab, and the laminate have low electrolyte resistance. The aqueous surface treatment agents of Comparative Examples 4 and 5 use a water-soluble cerium compound as the cerium compound material, so the positive electrode tab, the negative electrode tab, and the laminate have low electrolyte resistance. The aqueous surface treatment agents of Comparative Examples 6 to 9 use an inorganic phosphorus compound or its salt as the phosphorus compound, so the positive electrode tab, the negative electrode tab, and the laminate have low electrolyte resistance. The aqueous surface treatment agent of Comparative Example 10 uses ammonium polyacrylate as a resin component, but does not contain an oxazoline-containing resin (C), so the positive electrode tab, the negative electrode tab, and the laminate have low electrolyte resistance. The aqueous surface treatment agent of Comparative Example 11 was not able to be used as an aqueous surface treatment agent for treating a metal surface because precipitation occurred immediately after the cerium oxide sol and the polyallylamine were mixed.

[0147] Industrial Applicability

[0148] According to the present invention, it is possible to provide an aqueous surface treatment agent which can improve the adhesion between the metal and the laminated film after lamination and the electrolyte resistance when the metal is used as a secondary battery tab by being used for the surface treatment of the metal.

Claims

1. An aqueous surface treatment agent, which is an aqueous surface treatment agent for metal surface treatment, comprising: Cerium oxide sol (A); an organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group; and Oxazoline group-containing resin (C).

2. The aqueous surface treatment agent according to claim 1, wherein The oxazoline group-containing resin (C) accounts for 50% or more of the solid content by mass of the resin component of the aqueous surface treatment agent.

3. The aqueous surface treatment agent according to claim 1, wherein The organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group has a total of two or more phosphonic acid groups and / or phosphoric acid groups in one molecule.

4. The aqueous surface treatment agent according to claim 3, wherein The organic phosphorus compound (B) having a phosphonic acid group and / or a phosphoric acid group is phytic acid or a salt thereof. 5 . A surface-treated metal having a film formed by surface-treating the metal using the aqueous surface-treating agent according to claim 1 .

6. The surface-treated metal according to claim 5, wherein: The metal is aluminum or an aluminum alloy or copper or a copper alloy.

7. The surface-treated metal according to claim 5, wherein: The metal is plated.

8. The surface-treated metal according to claim 5, wherein: The metal film having the film has a polyolefin resin film layer on the film.

9. The surface-treated metal according to claim 8, which is a tab for a secondary battery.

10. The surface-treated metal according to claim 5, wherein: The metal having the film is subjected to lamination processing.

11. The surface-treated metal according to claim 10, which is an outer packaging material for a battery.

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