Surface treatment agent for aluminum-containing metal materials

Abstract

Provided is a surface treatment agent for an aluminum-containing metal material, which is capable of forming a film that is excellent in corrosion resistance and drainage and in which odor is suppressed. A surface treatment agent for an aluminum-containing metal material is compounded with a resin (A) having an ethylene structural unit and a hydroxy ethylene structural unit, an ether compound (B) having either or both of an epoxy group and a hydroxyl group, and a metal compound (C), the content of the ethylene structural unit in the resin (A) being 1 to 20 mol%.

Description

Technical Field

[0001] This invention relates to a surface treatment agent for aluminum-containing metal materials, a method for preparing a surface-treated metal material using the surface treatment agent, an aluminum-containing metal material having a surface-treated thin film, and a heat exchanger. Background Technology

[0002] Previously, heat exchangers used in air conditioners for buildings, vehicles, etc., were mostly made of aluminum-containing metal materials due to their superior workability and thermal conductivity. To improve heat exchange efficiency, the spacing between the aluminum-containing metal materials (generally referred to as fins) in the ventilation parts was designed to be very narrow. When the air conditioner is running (cooling), moisture in the atmosphere condenses on the fins, producing condensate. However, the higher the hydrophobicity of the fin surface, the larger the condensate droplets become, which are prone to clogging between the fins. If clogging occurs, ventilation resistance increases, heat exchange efficiency decreases, and the heat exchanger's intended performance cannot be achieved. In addition, clogging can sometimes increase noise during airflow. To solve these problems, a method of imparting hydrophilicity to aluminum-containing metal materials has been proposed and implemented.

[0003] For example, Patent Document 1 (Japanese Patent Application Publication No. 2016-222920) discloses an aqueous resin dispersion with excellent dispersion stability, comprising EVOH (A) and a free radical polymer (B) having structural units derived from a carboxylic acid monomer (B1-1) capable of free radical polymerization, wherein the content of the free radical polymer (B) is 10 to 80% by mass relative to the total amount of EVOH (A) and the free radical polymer (B). Patent Document 1 also discloses that the hydrophilic treatment agent containing this aqueous resin dispersion is preferably used for metals, especially aluminum and its alloys, and can form a hydrophilic film with excellent hydrophilicity, especially the persistence of hydrophilicity after the adsorption of pollutants, as well as excellent adhesion, drainage, and pollutant removal properties.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-222920 Summary of the Invention

[0007] The technical problem to be solved by the present invention

[0008] Although the aqueous resin dispersion described in Patent Document 1 has excellent dispersion stability, according to the inventors' research results based on the present invention, in more stringent tests for actual operating conditions of air conditioners, the hydrophilic film formed by using a hydrophilic treatment agent containing the aqueous resin dispersion cannot achieve sufficient performance in terms of corrosion resistance, drainage, and odor suppression.

[0009] The present invention was made in view of the above circumstances. In one embodiment, a surface treatment agent for aluminum-containing metal materials is provided, which is capable of forming a thin film with excellent corrosion resistance and drainage properties and suppresses odor.

[0010] Technical means for solving problems

[0011] The inventors of this invention conducted in-depth research to solve the above-mentioned problems and discovered that combining the following resin (A), ether compound (B), and metal compound (C) is advantageous for obtaining a surface treatment agent for aluminum-containing metal materials. This surface treatment agent can form a thin film with excellent corrosion resistance and drainage properties, and suppresses odors, thus completing this invention.

[0012] The present invention is specifically described by way of example below. [1]

[0014] A surface treatment agent for aluminum-containing metal materials, wherein the surface treatment agent comprises a resin (A) having ethylene structural units and hydroxyethylene structural units, an ether compound (B) having any one or both of epoxy groups and hydroxyl groups, and a metal compound (C), wherein the content of ethylene structural units in the resin (A) is 1 to 20 mol%. [2]

[0016] According to the surface treatment agent described in [1], the mass of the resin (A), ether compound (B), and metal compound (C) contained in the surface treatment agent is respectively expressed as M A M B and M C It is stated that, in order to establish M A / (M B +M C The relationship is to coordinate in a way that is between 0.1 and 3.0. [3]

[0018] According to the surface treatment agent described in [1] or [2], wherein the mass of the ether compound (B) and the metal compound (C) contained in the surface treatment agent is respectively expressed as M B and M C It is stated that, in order to establish M B / M C The relationship is to be matched in a way that is between 0.1 and 3.0. [4]

[0020] The surface treatment agent according to any one of [1] to [3], wherein the metal compound (C) is a silicon-containing oxide. [5]

[0022] A method for preparing a surface-treated metallic material, wherein the preparation method comprises: a step of contacting a surface treatment agent as described in any one of [1] to [4] with the surface of an aluminum-containing metallic material or on the surface of the material; and a step of drying the surface treatment agent after the contacting step. [6]

[0024] An aluminum-containing metal material, wherein the aluminum-containing metal material has a surface-treated film, the surface-treated film being formed by contacting the surface treatment agent described in any one of [1] to [4] with the surface of the aluminum-containing metal material or the surface of the surface. [7]

[0026] A heat exchanger having the aluminum-containing metal material described in [6].

[0027] Invention Effects

[0028] According to one embodiment of the present invention, a surface treatment agent for aluminum-containing metal materials can be provided, which exhibits excellent corrosion resistance and drainage properties, and suppresses odor. Therefore, the present invention can help improve the performance of heat exchangers, for example, those incorporating aluminum-containing metal materials, and especially air conditioners with aluminum-containing metal materials as fins. Detailed Implementation

[0029] The embodiments of the present invention will now be described in detail, including surface treatment agents and surface-treated metallic materials. Furthermore, the present invention can be modified arbitrarily without departing from its spirit and is not limited to the embodiments described below. Additionally, the "~" used to indicate numerical ranges in this specification includes both upper and lower limits. For example, "X~Y" means X or higher and Y or lower.

[0030] <1. Surface Treatment Agent>

[0031] According to one embodiment of the present invention, a surface treatment agent for aluminum-containing metal materials is provided, the surface treatment agent comprising a resin (A) having ethylene structural units and hydroxyethylene structural units, an ether compound (B) having either or both of epoxy groups and hydroxyl groups, and a metal compound (C), wherein the content of ethylene structural units in the resin (A) is 1 to 20 mol%.

[0032] [1-1. Resin (A)]

[0033] Resin (A) has ethylene structural units and hydroxyethylene structural units. Resin (A) is an ethylene-vinyl alcohol copolymer (hereinafter referred to as "EVOH"), and water solubility is ensured by making the content of ethylene structural units 1 to 20 mol%. Water solubility has the advantage of improving processability. Resin (A) can be used alone or in combination of two or more. The lower limit of the content of ethylene structural units in resin (A) is preferably 3 mol% or more, more preferably 5 mol% or more. The upper limit of the content of ethylene structural units in resin (A) is preferably 17 mol% or less, more preferably 14 mol% or less. Therefore, the content of ethylene structural units in resin (A) is preferably, for example, 3 to 17 mol%, more preferably 5 to 14 mol%.

[0034] The content of ethylene structural units in resin (A) (also known as "ethylene modification rate") can be determined by proton NMR. The specific determination procedure is as follows: Add resin (A) to deionized water and heat to 85°C–95°C to dissolve it. Dilute it with dimethyl sulfoxide (DMSO)-d6 to a resin (A) concentration of 1.0% by mass, as the NMR sample. Perform proton NMR determination using an NMR analyzer (e.g., JNM-EX400: NEC Corporation). The determination is performed under the following conditions.

[0035] Determination of nuclides: 1H

[0036] Observed temperature: 25.1℃

[0037] The peaks in the obtained spectrum are assigned as follows.

[0038] • 1.0–2.0 ppm: Methylene protons of ethylene structural units and methylene protons of hydroxyethylene structural units

[0039] • 3.7–4.1 ppm: Methylene protons of hydroxyethylene structural units adjacent to at least one ethylene structural unit

[0040] • 4.1–4.5 ppm: Methylene protons of hydroxyethylene structural units that are not adjacent to ethylene structural units.

[0041] According to the above classification, if the integral value of 1.0 to 2.0 ppm is set as x, the integral value of 3.7 to 4.1 ppm is set as y, and the integral value of 4.1 to 4.5 ppm is set as z, then the ethylene modification rate can be calculated by the following formula.

[0042] Ethylene modification rate = {(x-2y-2z) / 4} / {y+z+(x-2y-2z) / 4}

[0043] The upper limit of the weight-average molecular weight of resin (A) is preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 50,000 or less. Furthermore, the lower limit of the weight-average molecular weight of resin (A) is preferably 1,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more. Therefore, the weight-average molecular weight of resin (A) is preferably, for example, 1,000 to 100,000, more preferably 5,000 to 80,000, and even more preferably 10,000 to 50,000. The weight-average molecular weight of resin (A) can be determined by the GPC method.

[0044] The lower limit of the degree of saponification of resin (A) is preferably 90 mol% or more, more preferably 95 mol% or more. There is no specific upper limit set for the degree of saponification of resin (A), and it can be 100 mol%. The degree of saponification of resin (A) is determined according to JIS K6726-1994.

[0045] Resin (A) can be manufactured according to a known method for preparing EVOH, without particular limitation. For example, a method can be employed where ethylene and a vinyl ester are subjected to free radical polymerization in a predetermined molar ratio to obtain an ethylene-vinyl ester copolymer, followed by saponification. Examples of vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl tert-valerate, vinyl tert-valerate, and vinyl hexanoate. Vinyl acetate is preferred.

[0046] [1-2. Ether compounds (B)]

[0047] The ether compound (B) has either an epoxy group or a hydroxyl group, or both. The ether compound (B) acts as a binder, improving the film's durability by inhibiting resin (A) runoff. The ether compound (B) is not limited and may include polyalkylene glycols, polyalkylene glycol alkyl ethers, carbohydrates having pyranose or furanose structures, silane compounds containing glycidyl groups, and glycidyl ether compounds, etc. The ether compound (B) can be used alone or in combination of two or more.

[0048] Examples of polyalkylene glycols include polyethylene glycol and polypropylene glycol. Examples of polyalkylene glycol alkyl ethers include polyethylene glycol (mono) methyl ether, poly(ethylene, propylene) glycol (mono) methyl ether, and polyethylene glycol (mono) ethyl ether.

[0049] Examples of carbohydrates having pyranose or furanose structures include polysaccharides such as starch, glycogen, cellulose, chitin, and dextran, as well as their derivatives. Cellulose derivatives that are polysaccharide derivatives include alkyl celluloses such as methyl cellulose (MC), hydroxyalkyl celluloses such as hydroxypropyl cellulose (HPC) and hydroxyethyl cellulose (HEC), hydroxyalkyl celluloses such as hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl ethyl cellulose (HEEC), and sodium carboxymethyl cellulose (CMC-Na).

[0050] Examples of silane compounds containing glycidyl groups include 3-glycidylpropylmethyldimethoxysilane, 3-glycidylpropyldimethylmethoxysilane, 3-glycidylpropyltrimethoxysilane, 3-glycidylpropylethyldiethoxysilane, 3-glycidylpropyldiethylethoxysilane, and 3-glycidylpropyltriethoxysilane.

[0051] Examples of glycidyl ether compounds include sorbitol polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, phenolic glycidyl ethers containing ethylene oxide, lauryl ethers containing ethylene oxide, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD ​​type epoxy resin, etc.

[0052] [1-3. Metal compounds (C)]

[0053] The metal compound (C) acts as an inhibitor of corrosion in various environments, ensuring excellent corrosion resistance over a long period by being mixed in the film. Examples of such metal compounds (C) include those containing at least one metal selected from Si, Ti, V, Cr, Mn, Co, Zn, Zr, Mo, Ce, and W. Preferably, it contains at least one metal selected from Si, Ti, V, and Zr, and more preferably, it is a silicon compound. The metal compound (C) can take the form of oxides, hydroxides, fluorides, chlorides, carbonates, nitrates, sulfates, acetates, phosphates, organic acid salts, etc., and its type is not particularly limited. Furthermore, in this specification, Si is also treated as a metal. One metal compound (C) can be used alone, or two or more can be used in combination.

[0054] Examples of silicon compounds include silicon dioxide and its hydrates, silicates, and silicon-containing oxides such as organoalkoxysilanes. Silicon dioxide can preferably be used in the form of fumed silica (also called "fumed silica"), wherein silicon dioxide particles are synthesized by vaporizing silicon chlorides in a high-temperature hydrogen flame via a gas-phase reaction. Alternatively, silicon dioxide can preferably be used in the form of colloidal silica, wherein colloidal silica is obtained by reacting dilute hydrochloric acid with silicates followed by dialysis.

[0055] As a silicate, examples include silicates represented by M2O·nSiO2 (n is 1 to 8, and M represents Na, K, Li or NH4).

[0056] Organoalkoxysilanes have an alkoxysilyl group. When this alkoxysilyl group comes into contact with water, it hydrolyzes to form a silanol group (Si-OH), which then crosslinks to form a siloxane compound.

[0057] Examples of titanium compounds include titanium oxide, titanium hydrofluoric acid and its salts (potassium, ammonium, etc.), titanium sulfate and its salts (potassium, ammonium, etc.), titanium oxysulfate, titanium acetylacetone, titanium tetraacetylacetone, titanium lactate, and titanium triethanolamine.

[0058] Vanadium compounds include vanadium pentoxide, metavanadates (sodium, potassium, ammonium salts, etc.), vanadium pentafluoride, vanadium sulfate, vanadium acetylacetonate, and vanadium acetylacetonate oxyacetate.

[0059] Chromium compounds include chromium oxide, dichromic acid and its salts (sodium, potassium, ammonium salts, etc.), chromium fluoride, chromium carbonate, chromium nitrate, chromium sulfate, chromium phosphate, chromium dihydrogen phosphate, and chromium acetylacetone.

[0060] Manganese compounds include manganese oxide, manganates (sodium, potassium, etc.), permanganic acid and its salts (sodium, potassium, calcium, barium, lithium, etc.), manganese carbonate, manganese nitrate, manganese phosphate, manganese hydrogen phosphate, manganese acetylacetone, etc.

[0061] Examples of cobalt compounds include cobalt oxide, cobalt hydroxide, cobalt carbonate, cobalt nitrate, cobalt sulfate and its salts (potassium, ammonium, etc.), cobalt phosphate, cobalt pyrophosphate, and cobalt acetylacetonate.

[0062] Examples of zinc compounds include zinc oxide, zinc hydroxide, zinc carbonate, zinc nitrate, zinc sulfate and its salts (potassium, ammonium, etc.), zinc phosphate, zinc hydrogen phosphate, zinc acetylacetonate, etc.

[0063] Examples of zirconium compounds include zirconium oxide, zirconium hydroxide, zirconium hydrofluoride and its salts (potassium, ammonium, etc.), zirconium oxychloride, zirconium hydroxychloride, zirconium ammonium carbonate, potassium zirconium carbonate, zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium phosphate, zirconium sodium phosphate, zirconium propionate, zirconium monoacetylacetone, zirconium diacetylacetone, zirconium tetraacetylacetone, zirconium diacetylacetone, zirconium acetate, zirconium stearate, zirconium octanoate, etc.

[0064] Examples of molybdenum compounds include molybdenum oxide, molybdic acid and its salts (sodium, potassium, magnesium, ammonium salts, etc.), and molybdenum acetylacetonate.

[0065] Examples of cerium compounds include cerium oxide, cerium hydroxide, cerium chloride, cerium carbonate, cerium sulfate and its ammonium salts, cerium nitrate, cerium ammonium nitrate, cerium acetate, cerium phosphate, cerium octanoate, and cerium acetylacetone.

[0066] Examples of tungsten compounds include tungsten oxide, tungstic acid and its salts (sodium, potassium, magnesium, ammonium salts, etc.).

[0067] Alternatively, composite compounds of the aforementioned metals, such as zinc dichromate, zinc permanganate, cobalt tungstate, cerium tungstate, and pigments as mixtures of oxides, can also be used.

[0068] [1-4. The proportions of resin (A), ether compound (B), and metal compound (C)]

[0069] If the masses of the resin (A), ether compound (B), and metal compound (C) contained in the surface treatment agent are respectively expressed as M... A M B and M C In other words, resin (A), ether compound (B), and metal compound (C) are preferably in the form of M. A / (M B +M C The ratio is 0.1 or higher, and it is more preferable to use M. A / (M B +M C The formulation is combined with a concentration of 0.2 or higher, and more preferably with M. A / (M B +M C The formulation is carried out in a manner where the concentration is 0.3 or higher. Furthermore, the resin (A), ether compound (B), and metal compound (C) are preferably in the form of M... A / (M B +M C For formulations with a power rating of 3.0 or lower, M is preferred. A / (M B +M C The formulation is designed for use with a power rating of 2.0 or lower, and more preferably with M. A / (MB +M C The formulation is carried out in a manner where the concentration is 1.0 or less. Therefore, the resin (A), ether compound (B), and metal compound (C) are preferably formulated, for example, in the manner of forming M. A / (M B +M C The relationship between M and 0.1 is used to coordinate the elements, and it is more preferable to establish M. A / (M B +M C The relationship is to be coordinated in a manner that is 0.2 to 2.0, and it is even more preferable to establish M. A / (M B +M C The relationship is to coordinate in a way that is between 0.3 and 1.0.

[0070] If M respectively B and M C The mass of the ether compound (B) and metal compound (C) contained in the surface treatment agent is indicated, wherein the ether compound (B) and metal compound (C) are preferably in the form of M. B / M C It is better to use M in a manner that is greater than 0.1. B / M C It is combined in a manner of 0.2 or higher, and even more preferably with M. B / M C The formulation is carried out in a manner of 0.3 or higher. Furthermore, the ether compound (B) and the metal compound (C) are preferably formulated in the form of M. B / M C For use with a configuration of 3.0 or lower, M is preferred. B / M C For use with a configuration below 2.0, it is even more preferable to use M. B / M C The formulation is carried out in a manner below 1.0. Therefore, the ether compound (B) and the metal compound (C) are preferably formulated, for example, to form M. B / M C The relationship between M and 0.1 is used to coordinate the elements, and it is more preferable to establish M. B / M C The relationship between M and 0.2 is used to coordinate the elements, and it is even more preferable to establish M. B / M C They are matched in a way that maintains a relationship between 0.3 and 1.0.

[0071] [1-5. Other ingredients]

[0072] Surface treatment agents can contain various additives as needed, such as antibacterial agents, lubricants, surfactants, pigments, dyes, and inhibitors for imparting corrosion resistance. Furthermore, to dissolve resin (A), the surface treatment agent preferably contains water, or a mixture of water and a water-soluble solvent. From the perspective of facilitating the handling of the surface treatment agent, deionized water is preferred as the water. The water content is preferably 80-99% by mass, more preferably 85-95% by mass, relative to the total amount of the surface treatment agent. When using a mixture of water and a water-soluble solvent, the water proportion is preferably, for example, 60% by mass or more, relative to the total amount of the mixed solvent. As for the water-soluble solvent, there are no particular limitations as long as it does not undergo phase separation when mixed with water; examples include alcohols such as methanol and ethanol.

[0073] [1-6. Preparation Method]

[0074] The surface treatment agent can be prepared, for example, by mixing the above-mentioned components in the desired proportions, adding the required amount of water to the mixture, and stirring.

[0075] <2. Surface-treated metallic materials>

[0076] According to one embodiment of the present invention, a method for preparing a surface-treated metallic material is provided, comprising: a step of contacting a surface-treated agent with the surface of an aluminum-containing metallic material; and a step of drying the surface-treated agent after the contacting step. Furthermore, this preparation method yields an aluminum-containing metallic material having a surface-treated thin film. The proportions of resin (A), ether compound (B), and metal compound (C) in the surface-treated thin film are substantially the same as those in the surface-treated agent. The aluminum-containing metallic material thus prepared with a surface-treated thin film on its surface is useful for forming finned materials. Additionally, this finned material is useful as a component of a heat exchanger.

[0077] [2-1. Aluminum-containing metal materials]

[0078] The materials that make up aluminum-containing metallic materials can be pure aluminum or aluminum alloys.

[0079] [2-2. Cleaning Steps]

[0080] Untreated aluminum-containing metal materials are preferably pre-cleaned with an acidic or alkaline cleaning agent. Examples of acidic cleaning agents include acidic aqueous solutions containing at least one of nitric acid, sulfuric acid, and hydrofluoric acid. Examples of alkaline cleaning agents include alkaline aqueous solutions containing at least one of sodium hydroxide, sodium silicate, and sodium phosphate. To improve cleaning performance, surfactants can be added to the alkaline aqueous solution. Cleaning methods for aluminum-containing metal materials include, for example, immersion and spraying.

[0081] [2-3. Rust prevention treatment]

[0082] Rust prevention treatment can also be performed after the cleaning step. Rust prevention methods include chemical conversion treatment and rust prevention treatment using a resin primer. Examples of chemical conversion agents used in chemical conversion treatment include conventionally known chromate treatment agents, chromate phosphate treatment agents, or non-chromate treatment agents. Examples of resin primers include conventionally known water-soluble or water-dispersible aqueous resins. Rust prevention methods for aluminum-containing metal materials include, for example, immersion methods and spraying methods.

[0083] [2-4. Contact Steps]

[0084] There are no particular limitations on the method of bringing the surface treatment agent into contact with the surface of an aluminum-containing metal material; examples include immersion, spraying, roller coating, and brush coating. The temperature of the surface treatment agent can be set to approximately 10–50°C. The contact time can be set to approximately 3 seconds–5 minutes.

[0085] [2-5. Drying Steps]

[0086] As a method for drying the surface treatment agent, any method that evaporates the water in the surface treatment agent is acceptable, and there are no particular limitations. Examples include drying methods using known drying equipment, such as ovens, intermittent drying furnaces, continuous hot air circulating drying furnaces, conveyor belt hot air drying furnaces, and electromagnetic induction heating furnaces using IH heaters. The drying temperature can be set to 100–250°C, preferably 120–180°C. The drying time can be set to 10 seconds–120 minutes, preferably 1–60 minutes.

[0087] [2-6. Quality of Surface-Treatment Film]

[0088] In aluminum-containing metal materials with surface-treated films, the mass of the surface-treated film is not particularly limited as long as it is sufficient to achieve the effects of the present invention; preferably, it is per 1m. 2 The amount is in the range of 0.01 to 5.0g, more preferably in the range of 0.05 to 3.5g, and particularly preferably in the range of 0.1 to 2.0g.

[0089] (Post-processing steps)

[0090] After forming the surface-treated film, a post-treatment step can be performed. Examples of post-treatment steps include a lubricant contact step or a lubricant film formation step. More specifically, this step can be exemplified by contacting lubricant or a lubricant onto the surface-treated film on the surface of the aluminum-containing metal material to form a lubricant film. In this way, an aluminum-containing metal material with multiple layers of films can be obtained, wherein lubricant is contacted or a lubricant film is formed on the aforementioned surface-treated film. Furthermore, there are no particular limitations on the method of contacting the lubricant or lubricant; examples include roller coating, spraying, and dipping.

[0091] As a lubricant, known lubricants used in molding processes can be used. Additionally, as a lubricant for forming a lubricating film, known lubricants such as water-soluble polyethers, polyethylene glycol, polyoxyethylene alkyl ethers, and polyoxyethylene hydrogenated castor oil ethers can be used.

[0092] Example

[0093] The present invention will now be described in more detail based on embodiments, but the present invention is not limited to these embodiments.

[0094] <Manufacturing of Resin (A)>

[0095] [Synthesis example 1]

[0096] In a 2L autoclave reactor equipped with a reflux condenser, raw material inlet, thermometer, nitrogen inlet, and stirring blades, 25g of vinyl acetate and 120g of methanol were added while nitrogen was introduced. A 2% methanol solution of 2,2'-azobis(2,4-dimethylpentanonitrile) as an initiator was added in small increments of 25ml. The ethylene pressure in the autoclave was adjusted to 0.7MPa, and polymerization was initiated at 60°C. After 5 hours of reaction, unreacted vinyl acetate was removed under reduced pressure, resulting in a methanol solution of ethylene vinyl acetate resin. A 10% sodium hydroxide aqueous solution was added to the obtained ethylene vinyl acetate resin methanol solution to achieve a molar ratio of sodium hydroxide phase to vinyl acetate (25g) used as raw material of 0.01. Saponification was carried out at 50°C for 1 hour. Subsequently, methanol was removed by reduced pressure distillation, water was removed by centrifugation, and the product was dried to obtain an ethylene-vinyl alcohol copolymer (resin (A)) powder with a saponification degree of 98%. Take 5g of the obtained powder and place it in 95g of warm water at 85-95℃. Heat and stir for 2-3 hours until completely dissolved. The ethylene modification rate of the obtained powder was determined by proton NMR, and the result was 10 mol%. The weight-average molecular weight was determined by gel permeation chromatography (GPC), and the result was 9000. Each analysis was performed under the following conditions.

[0097] 1) Proton NMR

[0098] The obtained sample was added to deionized water and heated to 85–95°C to dissolve it. It was then diluted with dimethyl sulfoxide (DMSO)-d6 to a resin (A) concentration of 1.0% by mass, serving as the NMR sample. Proton NMR was performed using a nuclear magnetic resonance analyzer (JNM-EX400: NEC Corporation). The measurement conditions and the method for calculating the ethylene modification rate are as described above.

[0099] 2) GPC

[0100] The determination was performed using a high-speed GPC apparatus (HLC-8320GPC: manufactured by Tosoh Corporation), and the weight-average molecular weight was determined using a combination of SEC column and guard column. The determination was conducted under the following conditions.

[0101] SEC column: TSKgel SuperAWM-H (manufactured by Tosoh Corporation)

[0102] Protective pillar: TSKgurdcolumn SuperAW-H (manufactured by Tosoh Corporation)

[0103] Detector: RI (HLC-8320GPC built-in detector)

[0104] Standard sample: polystyrene

[0105] Sample injection volume: 30 μL of 0.06% DMF solution

[0106] Flow rate: 0.5 mL / min

[0107] Elution buffer: DMF / 100mM LiBr / 60mM H3PO4

[0108] [Synthesis example 2-8]

[0109] Except for the conditions shown in Table 1, resin (A) was synthesized in exactly the same manner as in Synthesis Example 1. The ethylene modification rate, molecular weight, and degree of saponification of the obtained resin (A) are shown in Table 2. Furthermore, corresponding to the numbering of the synthesis examples, the obtained resin (A) is referred to as A1, A2, A3, etc. 5g of each of the obtained resins A1 to A6 were placed in 95g of warm water at 85–95°C and heated and stirred for 2–3 hours until completely dissolved. Resins A7 and A8 failed to dissolve in the above method.

[0110] [Synthesis Example 9]

[0111] Except for the conditions shown in Table 1, resin (A) was synthesized in exactly the same manner as in Synthesis Example 1. Nitrogen gas (0.1 MPa) was used instead of ethylene for pressurization during the polymerization process. The ethylene modification rate, molecular weight, and saponification degree of the obtained resin (A) are shown in Table 2. 5 g of the obtained resin A9 was taken and placed in 95 g of warm water at 85–95 °C, and heated and stirred for 2–3 hours until completely dissolved.

[0112] Table 1

[0113]

[0114] <Preparation of Surface Treatment Agents>

[0115] Tables 2 through 4 show the raw materials used in the surface treatment agents of the examples and comparative examples. Table 2 lists the resin (A) used in the examples and comparative examples. Table 3 lists the ether compound (B) used in the examples and comparative examples. Table 4 lists the metal compound (C) used in the examples and comparative examples.

[0116] Table 2

[0117]

[0118] Table 3

[0119] Symbol Substance name B1 Polyethylene glycol B2 Sodium carboxymethylcellulose B3 3-glycidylpropyltrimethoxysilane B4 Sorbitol polyglycidyl ether

[0120] Table 4

[0121] Symbol Substance name C1 Fumed silica C2 Colloidal silica C3 Ammonium zirconium carbonate C4 Vanadium sulfate

[0122] The surface treatment agents of the examples and comparative examples were prepared as follows: resin (A), ether compound (B) and inorganic compound (C) were mixed in the mass ratio shown in Table 5. Then, 40g of the solid component of the resulting mixture was mixed with deionized water to make a total of 1000g and stirred.

[0123] Table 5

[0124]

[0125] <Manufacturing of Experimental Heat Exchangers>

[0126] An aluminum heat exchanger (NB heat exchanger) from a household air conditioner was used as the test heat exchanger. The surface treatment of the test heat exchanger was then performed under the following conditions.

[0127] Formation of Surface Treatment Thin Films

[0128] The test heat exchanger was immersed in a treatment bath containing 20 g / L of the alkaline degreasing agent "Fine Cleaner 4424" (manufactured by Pakase Seiki Co., Ltd., Japan) at 50°C for 2 minutes to remove dust and oil adhering to the surface. Afterward, the surface was rinsed with tap water to remove any remaining alkaline components. Next, the test heat exchanger was coated with the surface treatment agent described in each example and comparative example. The test heat exchanger was then placed in a drying oven at 150°C for 20 minutes to form a surface treatment film on its surface, thus creating an evaluation sample. The mass of the surface treatment film was adjusted to 0.8 g / m³. 2 .

[0129] <Odor Evaluation Methods>

[0130] After cooling the prepared evaluation samples to room temperature, they were immediately placed in an air conditioner, and the air conditioner was repeatedly started and stopped four times. Each time, a judge evaluated the odor from a distance of 10–20 cm from the air conditioner's outlet. The odor during the cooling-on start-up and cooling-off start-up phases were taken as the initial odor. Next, the evaluation samples were immersed in deionized water for 72 hours, dried in an air dryer set to 50°C for 2 hours, cooled to room temperature, and then placed in an air conditioner, and the air conditioner's cooling-on start-up and cooling-off phases were repeated four times. Each time, a judge evaluated the odor from a distance of 10–20 cm from the air conditioner's outlet. The odor during the cooling-on start-up and cooling-off start-up phases were taken as the durable odor. The odor at each time point was evaluated according to the following evaluation criteria. The evaluation standard used was the odor intensity at a specified concentration of isovaleric acid, which was used as the standard odor component. The average score of the four judges' evaluations was taken. If the score was below 3 points according to the evaluation standard, the odor was considered to be good. The results are shown in Table 6.

[0131] (Evaluation Criteria)

[0132] 5 points: Strong odor (isovaleric acid concentration: 30 μg / L)

[0133] 4 points: Easily detectable odor (isovaleric acid concentration: 4 μg / L)

[0134] 3 points: Can identify the type of odor, a relatively weak odor (recognition threshold: isovaleric acid concentration: 0.4 μg / L)

[0135] 2 points: A barely perceptible odor (detection threshold: isovaleric acid concentration: 0.05 μg / L)

[0136] 1 point: Odorless

[0137] <Drainage Performance Evaluation Methods>

[0138] The prepared evaluation samples were placed in an air conditioner, and the air conditioner was run to confirm the amount of water retained in the evaluation samples after 30 minutes of cooling operation (water retention). The formula for calculating water retention is {(weight of the evaluation sample after cooling - weight of the evaluation sample after drying) / thermal conductivity area of ​​the evaluation sample}. The lower the water retention, the better the drainage performance and the better the heat exchange efficiency. The evaluation criteria for water retention are shown below. If the score is below 3 points according to the evaluation criteria, the drainage performance is considered good. The evaluation samples were immersed in deionized water for 72 hours, dried in a blower dryer set to 50°C for 2 hours, and then cooled to room temperature before use. The results are shown in Table 6.

[0139] (Evaluation Criteria)

[0140] 5 points: 70g / m 2 above

[0141] 4 points: 60g / m 2 Above and below 70g / m 2

[0142] 3 points: 50g / m 2 Above and below 60g / m 2

[0143] 2 points: 40g / m 2 Above and below 50g / m 2

[0144] 1 point: less than 40g / m 2

[0145] <Corrosion Resistance Evaluation Methods>

[0146] The prepared evaluation samples were exposed for 720 hours according to the salt spray test method (JIS Z-2371), and the rust area (the ratio of white rust area to the total area) of the fins was evaluated by visual observation. The evaluation criteria are shown below. If the score is below 3 points according to the evaluation criteria, the corrosion resistance is considered good. The results are shown in Table 6.

[0147] (Evaluation Criteria)

[0148] 5 points: White rust covers more than 70% of the area.

[0149] 4 points: White rust covers more than 50% but less than 70% of the area.

[0150] 3 points: White rust covers an area of ​​30% or more but less than 50%.

[0151] 2 points: White rust area is more than 10% but less than 30%.

[0152] 1 point: White rust area is less than 10%

[0153] Table 6

[0154]

Claims

1. A surface treatment agent for aluminum-containing metal materials, wherein, The surface treatment agent comprises a resin (A) having ethylene structural units and hydroxyethylene structural units, an ether compound (B) having either or both of epoxy and hydroxyl groups, and a metal compound (C). The content of ethylene structural units in the resin (A) is 1-20 mol%. The mass of the ether compound (B) and the metal compound (C) contained in the surface treatment agent is respectively expressed as M. B and M C It is stated that, in order to establish M B / M C The relationship between 0.1 and 3.0 is used for coordination; and in, The resin (A) is selected from ethylene-vinyl alcohol copolymer, and the metal compound (C) is a compound containing at least one metal selected from Si, Ti, V, Cr, Mn, Co, Zn, Zr, Mo, Ce and W.

2. The surface treatment agent according to claim 1, wherein, The mass of the resin (A), ether compound (B), and metal compound (C) contained in the surface treatment agent is respectively expressed as M. A M B and M C It is stated that, in order to establish M A / (M) B +M C The relationship is to coordinate in a way that is between 0.1 and 3.

0.

3. The surface treatment agent according to claim 1 or 2, wherein, The masses of the ether compound (B) and the metal compound (C) contained in the surface treatment agent are respectively expressed as M. B and M C It is stated that, in order to establish M B / M C The relationship is to be coordinated in a way that is between 0.2 and 2.

0.

4. The surface treatment agent according to claim 1 or 2, wherein, The metal compound (C) is a silicon-containing oxide.

5. A method for preparing a surface-treated metallic material, wherein, The preparation method includes: contacting the surface treatment agent according to any one of claims 1 to 4 with the surface of an aluminum-containing metal material; and drying the surface treatment agent after the contacting step.

6. An aluminum-containing metal material, wherein, The aluminum-containing metal material has a surface treatment film, which is formed by contacting the surface treatment agent of any one of claims 1 to 4 with the surface of the aluminum-containing metal material or on the surface of the surface.

7. A heat exchanger, wherein, The heat exchanger has the aluminum-containing metal material as described in claim 6.

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