Metal surface treatment chemicals, metal material manufacturing methods, and metal materials.

Abstract

The invention proposes a metal surface treatment chemical, a method for producing a metal material with a surface treatment film, and a metal material with a surface treatment film. The metal surface treatment chemical has superior properties not only in coating adhesion and corrosion resistance in conventional bending and salt spray testing but also in coating adhesion and corrosion resistance under high load and severe evaluation conditions as recently required, specifically in cylindrical machining and combined cycle testing. The invention also proposes a metal surface treatment chemical. In the metal surface treatment chemical, at least one zirconium source (A) and at least one silane binding agent (B) are blended. The silane binding agent (B) has an amino group. The ratio of the Zr content (WA) to the Si content (WB) (WA / WB) in the metal surface treatment chemical is between 0.18 and 2.34 by mass.The mass ratio of Zr (NA) to the non-volatile content of the metal surface treatment chemical is 1.2% by mass or more.

Description

Metal surface treatment agent, method for producing metal material, and metal material

[0001] The present invention relates to a metal surface treatment agent, a method for producing a metal material, and a metal material.

[0002] Traditionally, in fields such as steel, home appliances, building materials, and automobiles, chromium-based surface treatments, such as chromate treatments, have been used as temporary rust prevention treatments or primer treatments for paint films, as they provide excellent adhesion to metal materials and excellent corrosion resistance. These chromium-based surface treatments are still widely used. However, in light of recent trends in environmental regulations, their use may be restricted in the future due to the toxicity of chromium, particularly its carcinogenicity. Furthermore, with the advancement of chromium-free metal surface treatments, there is a need for a metal surface treatment agent that can replace chromium-based surface treatments and has the same adhesion and corrosion resistance as chromate treatments, even under more demanding and severe evaluation conditions than previously required.

[0003] For example, Patent Document 1 discloses a metal surface treatment agent that does not contain chromium on a zinc-plated steel sheet, can impart excellent workability and corrosion resistance to a PCM steel sheet, and has excellent storage stability.

[0004] Furthermore, Patent Document 2 discloses a primer treatment liquid that can form a primer layer that can improve the adhesion of an organic resin layer even on a zinc plating layer.

[0005] Furthermore, Patent Document 3 discloses an aqueous surface treatment agent that is environmentally friendly and chromium-free, and when used as a paint base for pre-coated metal materials, the resulting pre-coated metal materials have excellent paint adhesion (working adhesion of the coating film), corrosion resistance, and coin scratch resistance, and also have good storage stability.

[0006] JP 2001-240979 A JP 2016-108629 A JP 2006-328445 A

[0007] The coating formed by the metal surface treatment agent described in Patent Document 1 is effective to a certain extent in the evaluation of bending adhesion (0TT processing) and corrosion resistance (salt spray test). However, under more severe evaluation conditions with higher loads, both adhesion and corrosion resistance are insufficient, and better performance is required.

[0008] Furthermore, the coating formed by the primer treatment solution described in Patent Document 2 is effective in enhancing adhesion to an organic resin layer, such as polyethylene, intended to protect the outer surface of the steel pipe from corrosion, when used primarily for hot-dip galvanized steel pipes buried underground. However, as with Patent Document 1, under more severe evaluation conditions with higher loads, both adhesion and corrosion resistance are insufficient, and better performance is desired. Furthermore, the relatively high substrate coverage required for hot-dip galvanized steel pipe applications is economically disadvantageous.

[0009] The surface treatment agent described in Patent Document 3 is effective to a certain extent in the evaluation of corrosion resistance (salt spray test) and adhesion after processing (2T bending test). However, as with Patent Documents 1 and 2, under more severe evaluation conditions with higher loads, both adhesion and corrosion resistance are insufficient, and better performance is desired.

[0010] Therefore, an object of the present invention is to provide a metal surface treatment agent that not only satisfies the paint adhesion and corrosion resistance in bending processing and salt spray tests that have been required in the past, but also provides excellent paint adhesion and corrosion resistance under the high-stress and severe evaluation conditions that have been required in recent years, specifically, cylindrical processing and combined cycle tests; a method for producing a metal material having a surface treatment film using the same; and a metal material having a surface treatment film obtained by the production method.

[0011] One aspect of the present invention is a metal surface treatment agent comprising at least one zirconium source (A) and at least one silane coupling agent (B), wherein the silane coupling agent (B) has an amino group, the ratio (WA / WB) of the Zr content (WA) to the Si content (WB) in the metal surface treatment agent is 0.18 to 2.34 by mass, and the mass ratio (NA) of Zr to the non-volatile content of the metal surface treatment agent is 1.2 mass% or more.

[0012] In the metal surface treatment agent of the above embodiment, the zirconium source (A) may contain zirconium carbonate. The zirconium source (A) incorporated into the metal surface treatment agent may consist solely of zirconium carbonate. A metal compound (C) containing at least one metal selected from the group consisting of Ti, W, V, Co, Mo, Ca, Mg, and Li may be incorporated. At least one cationic or nonionic resin (D) selected from the group consisting of urethane resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, phenolic resin, and epoxy resin may be incorporated. The silane coupling agent (B) may have a primary amino group.

[0013] Another aspect of the present invention is a method for producing a metal material, which includes the steps of bringing a metal surface treatment agent according to any one of the above-described aspects into contact with a metal material, and drying the metal surface treatment agent that has been brought into contact with the metal material to form a surface treatment film.

[0014] Yet another aspect of the present invention is a metallic material obtained by the method for producing a metallic material according to the above-described aspect.

[0015] According to the present invention, it is possible to provide a metal surface treatment agent that not only satisfies the paint adhesion and corrosion resistance in bending processing and salt spray tests that have been required in the past, but also exhibits excellent paint adhesion and corrosion resistance under the high-stress and severe evaluation conditions that have been required in recent years, specifically, cylindrical processing and combined cycle tests; a method for producing a metal material having a surface treatment film using the same; and a metal material having a surface treatment film obtained by the production method.

[0016] Hereinafter, embodiments of the present invention will be described in detail. In this specification, the expression "a to b" in the description of a range of values ​​means that the range is from a to b, unless otherwise specified.

[0017] The metal surface treatment agent according to this embodiment, the method for producing a metal material having a surface treatment film using the same, and the metal material having a surface treatment film obtained by the production method will be described below.

[0018] <Metal Surface Treatment Agent> The metal surface treatment agent according to the embodiment contains at least one zirconium source (A) and at least one silane coupling agent (B). The metal surface treatment agent according to the embodiment can form a film having excellent paint adhesion and corrosion resistance on or above the surface of a metal material. Each component contained in the metal surface treatment agent according to the embodiment is dissolved or dispersed in an aqueous medium described below. The metal surface treatment agent according to the embodiment will be described in detail below.

[0019] (Zirconium Source (A)) Examples of the zirconium source (A) include zirconium carbonate. More specifically, examples of the zirconium carbonate include basic zirconium carbonate, zirconium oxycarbonate, ammonium zirconium carbonate, and potassium zirconium carbonate. These zirconium carbonates may be blended alone to produce a metal surface treatment agent, or two or more types may be blended to produce a metal surface treatment agent. Furthermore, nitrates, sulfates, carbonates, hydrofluorides, ammonium salts, potassium salts, sodium salts, and the like may be used as the zirconium source (A). The zirconium source (A) may be zirconium carbonate alone.

[0020] (Silane Coupling Agent (B)) The silane coupling agent (B) has an amino group. There are no particular limitations on the silane coupling agent (B) as long as it is a silane coupling agent having an amino group. The amino group possessed by the silane coupling agent (B) is not particularly limited, but examples include primary amino groups, secondary amino groups, and tertiary amino groups. Of these, a primary amino group is more preferable. The silane coupling agent (B) may have only one amino group, or may have two or more amino groups. Examples of the silane coupling agent (B) include N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(aminoethyl)3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. One or more of these silane coupling agents (B) may be blended into the metal surface treatment agent.

[0021] In the metal surface treatment agent according to this embodiment, the ratio (WA / WB) of the Zr content (WA) to the Si content (WB) is preferably 0.18 to 2.34 by mass, more preferably 0.26 to 2.34, and even more preferably 0.58 to 2.34. Furthermore, the mass ratio (NA) of Zr to the non-volatile content of the metal surface treatment agent according to this embodiment is preferably 1.2 mass% or more, more preferably 1.5 mass% or more, and even more preferably 2.0 mass% or more. The "non-volatile content" in the metal surface treatment agent refers to the substances remaining after heating the metal surface treatment agent at 110°C for 2 hours.

[0022] <Other Components> The metal surface treatment agent according to this embodiment may contain only the zirconium source (A) and the silane coupling agent (B) as components other than the aqueous medium, or may further contain other components such as a metal compound (C), a cationic or nonionic aqueous resin (D), a surfactant, etc.

[0023] (Metal Compound (C)) The metal compound (C) preferably contains at least one metal selected from the group consisting of Ti, W, V, Co, Mo, Ca, Mg, and Li. In other words, examples of the metal compound (C) include titanium compounds, tungsten compounds, vanadium compounds, cobalt compounds, molybdenum compounds, magnesium compounds, and lithium compounds. The titanium compound is not particularly limited as long as it is a compound containing titanium element, and examples thereof include hydrofluoric titanium acid, ammonium titanium fluoride, titanium sulfate, titanium oxysulfate, potassium titanium oxyoxalate, and diisopropoxytitanium bisulfate. The tungsten compound is not particularly limited as long as it is a compound containing tungsten element, and examples thereof include metatungstic acid, ammonium metatungstate, sodium metatungstate, paratungstic acid, ammonium paratungstate, and sodium paratungstate. The vanadium compound is not particularly limited as long as it contains vanadium element, and examples thereof include vanadium pentoxide, metavanadate, ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride, vanadium trioxide, vanadium dioxide, vanadium oxysulfate, vanadium oxyacetylacetonate, vanadium acetylacetonate, and vanadium trichloride. The cobalt compound is not particularly limited as long as it contains cobalt element, and examples thereof include cobalt chloride, chloropentaamminecobalt chloride, hexaamminecobalt chloride, cobalt chromate, cobalt sulfate, ammonium cobalt sulfate, cobalt nitrate, cobalt dialuminum oxide, cobalt hydroxide, and cobalt phosphate. The molybdenum compound is not particularly limited as long as it contains molybdenum element, and examples thereof include molybdenum oxide, molybdic acid, ammonium molybdate, ammonium paramolybdate, and sodium molybdate.The magnesium compound is not particularly limited as long as it is a compound containing magnesium element, and examples thereof include magnesium nitrate, magnesium sulfate, magnesium carbonate, magnesium hydroxide, magnesium fluoride, ammonium magnesium phosphate, magnesium hydrogen phosphate, magnesium oxide, etc. The lithium compound is not particularly limited as long as it is a compound containing lithium element, and examples thereof include lithium oxide, lithium hydroxide, lithium carbonate, lithium chloride, lithium nitrate, lithium sulfate, lithium silicate, etc. The metal surface treatment agent may contain one or more of these inorganic compounds.

[0024] When the metal surface treatment agent according to the present embodiment contains the metal compound (C), the blending ratio of the metal compound (C) is not particularly limited, but it is preferable that the ratio (NC) of the total non-volatile content of the metal compound (C) in terms of metal to the non-volatile content concentration of the metal surface treatment agent according to the present embodiment is in the range of 1 to 20 mass%.

[0025] (Cationic or Nonionic Aqueous Resin (D)) The cationic or nonionic aqueous resin (D) (hereinafter simply referred to as "aqueous resin (D)") is not particularly limited as long as it is a cationic or nonionic aqueous resin, and may be, for example, at least one selected from the group consisting of urethane resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, phenolic resin, acrylic resin, and epoxy resin. The aqueous resin (D) may be a homopolymer of a urethane resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, phenolic resin, acrylic resin, epoxy resin, or the like; a modified product in which the side chain of the homopolymer is modified with another compound; or a copolymer of two or more of these resins or modified products. The form of the water-solubilized aqueous resin (D) is not particularly limited; the aqueous resin (D) may be water-soluble or water-dispersible (emulsion, dispersion).

[0026] When the metal surface treatment agent according to the present embodiment contains the aqueous resin (D), the blending ratio of the aqueous resin (D) is not particularly limited, but it is preferable that the ratio (ND) of the total nonvolatile concentration of the aqueous resin (D) to the nonvolatile content concentration of the metal surface treatment agent according to the present embodiment is in the range of 5 to 50 mass %.

[0027] (Surfactant) As the surfactant, cationic, anionic, amphoteric, nonionic surfactants can be used, for example, cationic surfactants such as alkylamine salts and alkyltrimethylammonium halides; anionic surfactants such as alkylsulfonate esters, polyoxyethylene alkylphenyl ether sulfates, sodium dodecyldiphenyl ether disulfonate and sodium dodecyl sulfate; amphoteric surfactants such as alkylaminopropionates and alkyldimethylbetaines; nonionic surfactants such as polyoxyethylene alkylphenyl ethers, polyoxyalkylene fatty acid esters, fatty acid glycerin esters and polyoxyethylene propylene glycol fatty acid esters; etc. These surfactants may be used alone or in combination of two or more.

[0028] (Aqueous Medium) The aqueous medium is not particularly limited as long as it contains 50% by mass or more of water, and may be a medium consisting of water alone or a mixture containing water and a water-miscible organic solvent. The water-miscible organic solvent is not particularly limited as long as it is miscible with water, and examples thereof include ketone solvents such as acetone and methyl ethyl ketone; alcohol solvents such as methanol, ethanol, and isopropanol; ether solvents such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether; and pyrrolidone solvents such as 1-methyl-2-pyrrolidone and 1-ethyl-2-pyrrolidone. One of these water-miscible organic solvents may be mixed with water, or two or more may be mixed with water.

[0029] In the metal surface treatment agent according to this embodiment, the mass ratio of Cr to the non-volatile content of the metal surface treatment agent is preferably 0 mass %. By setting the mass ratio of Cr to 0 mass %, the metal surface treatment agent according to this embodiment can be used as a substitute for chromium-free or non-chromium chromium-based surface treatment agents, and thus the impact on the environment can be suppressed.

[0030] The metal surface treatment agent described above not only exhibits the paint adhesion and corrosion resistance in bending processing and salt spray tests that have been conventionally required, but also exhibits excellent paint adhesion and corrosion resistance under the highly stressful and severe evaluation conditions that have been required in recent years, specifically, under cylindrical processing and combined cycle tests.

[0031] <Method for Producing Metal Surface Treatment Agent> The metal surface treatment agent according to this embodiment can be produced, for example, by mixing predetermined amounts of the zirconium source (A), the silane coupling agent (B), and, if necessary, other components into an aqueous solvent.

[0032] <Metallic Material Having a Surface Treatment Film and Manufacturing Method Thereof> The manufacturing method for a metallic material having a surface treatment film according to this embodiment (hereinafter simply referred to as the "manufacturing method according to this embodiment") includes a contacting step of bringing the above-described metal surface treatment agent into contact with the surface or on the surface of a metallic material, and a drying step of drying the metal surface treatment agent that has been contacted with the surface or on the surface of the metallic material. This manufacturing method provides a metallic material having a coating on the surface or on the surface that has excellent paint adhesion and corrosion resistance. Note that the manufacturing method according to this embodiment may also include a degreasing step and / or a chemical conversion treatment step before the contacting step.

[0033] <Metallic Material> The shape and structure of the metallic material on which the coating is formed are not particularly limited, and examples thereof include plate and foil. The type of metallic material is also not particularly limited, and examples thereof include steel materials (e.g., cold-rolled steel sheets, hot-rolled steel sheets, black materials, pickled steel sheets, high-tensile steel sheets, tool steels, alloy tool steels, spheroidized graphite cast iron, gray cast iron, etc.); plated materials, such as zinc-plated materials (e.g., electrogalvanized, hot-dip galvanized, aluminum-containing zinc plating, electrogalvanized, zinc-nickel plating, zinc-cobalt plating, vapor-deposited zinc plating, etc.); zinc alloy-plated materials (e.g., alloyed hot-dip galvanized, Zn—Al alloy plating, Zn—Al-M alloy plating, etc.); zinc alloy plating, electrolytic zinc alloy plating, etc.), aluminum plated materials, nickel plated materials, tin plated materials, chrome plated materials, chrome alloy plated materials (for example, Cr-Ni alloy plating, etc.); aluminum materials or aluminum alloy materials (for example, 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, aluminum castings, aluminum alloy castings, die-cast materials, etc.); copper materials or copper alloy materials; titanium materials or titanium alloy materials; magnesium materials or magnesium alloy materials, etc.

[0034] <Contacting Step> Examples of the contacting method include, but are not limited to, spraying, immersion, roll coating, bar coating, curtain coating, spin coating, and combinations thereof. The contacting temperature and contacting time are appropriately set depending on the composition and concentration of the metal surface treatment agent, but typically the contacting temperature is in the range of 0°C or higher and 50°C or lower, and the contacting time is in the range of 1 second or higher and 300 seconds or lower.

[0035] <Drying Step> The drying method is not particularly limited, and examples thereof include drying methods using known drying equipment, such as a batch-type drying oven, a continuous hot air circulation drying oven, a conveyor-type hot air drying oven, an electromagnetic induction heating oven using an IH heater, etc. The drying temperature and drying time are appropriately set depending on the type of metal material and the composition or amount of the metal surface treatment agent that has been brought into contact, but typically the drying temperature is in the range of 60°C or higher and 250°C or lower, and the drying time is in the range of 1 second or higher and 1800 seconds or lower.

[0036] <Degreasing step> The degreasing method may be any method capable of removing grease and dirt, and examples thereof include known methods using solvent degreasing, alkaline or acidic degreasing agents, etc. When a contact step or chemical conversion treatment step is performed after the degreasing step, a step of rinsing the surface or the surface of the metal material with water may or may not be performed after the degreasing step and before the contact step or the chemical conversion treatment step. When rinsing with water is performed, the surface or the surface of the metal material may or may not be subsequently dried.

[0037] <Chemical Conversion Treatment Step> The chemical conversion treatment step is not particularly limited as long as it is a treatment that forms a chemical conversion coating, and examples thereof include a zirconium chemical conversion treatment step, a titanium chemical conversion treatment step, a nickel chemical conversion treatment step, a hafnium chemical conversion treatment step, a phosphate conversion treatment step, and a chromate chemical conversion treatment step. After the chemical conversion treatment step and before the contact step, a step of rinsing the surface or the surface of the metal material with water may or may not be performed. If rinsing with water is performed, the surface or the surface of the metal material may or may not be subsequently dried. Note that when a phosphate conversion treatment step using zinc phosphate is performed as the chemical conversion treatment step, a surface conditioning treatment step for the purpose of improving the reactivity of the phosphate conversion treatment may be performed on the metal material between the degreasing step and the phosphate conversion treatment step. A known method can be used as this surface conditioning treatment method.

[0038] <Chemical Conversion Treatment Agent> The chemical conversion treatment step is carried out by contacting a chemical conversion treatment agent with the surface or surfaces of the metal material. Examples of chemical conversion treatment agents include, but are not limited to, zirconium chemical conversion treatment agents, titanium chemical conversion treatment agents, nickel chemical conversion treatment agents, hafnium chemical conversion treatment agents, phosphate conversion treatment agents, and chromate chemical conversion treatment agents. Contact with the chemical conversion treatment agent can be carried out by known methods, such as, but not limited to, immersion treatment, spray treatment, pouring treatment, or a combination thereof. The temperature or contact time of the chemical conversion treatment agent in each chemical conversion treatment step can be appropriately set depending on the type of chemical conversion treatment step, the concentration of the chemical conversion treatment agent, etc.

[0039] <Surface Treatment Film> The film mass of the surface treatment film formed on the surface of a metal material by the metal surface treatment agent is not particularly limited as long as the performance of the metal surface treatment agent of this embodiment can be exhibited. For example, ２ 4g / m or more ２ It is preferable that the content is within the range of 0.05 g / m ２ 3g / m or more ２ It is more preferable that the content is within the following range.

[0040] The surface treatment film formed as described above has excellent paint adhesion and can therefore be used as a base film for pre-coated metal materials which usually have one to three coating layers on top.

[0041] The precoated metal material is produced by forming an upper coating layer on the surface treatment film, i.e., the base coating, formed on the metal material using the metal surface treatment agent of this embodiment as described above. The upper coating layer can be formed using a coating method commonly used for precoated steel sheets, such as a coating method in which a primer is applied to the base coating and dried, and then a top coat is applied, a coating method in which a top coat is applied directly without using a primer, or a method in which a laminate film is attached.

[0042] The primer is not particularly limited and typically contains a resin and, if necessary, a coloring pigment, an anti-rust pigment, etc. The resin may be in any form, such as water-based, solvent-based, or powder-based, and the type of resin may be generally known, such as polyacrylic resins, polyolefin resins, polyurethane resins, epoxy resins, polyester resins, polybutyral resins, melamine resins, and fluorine-based resins, which may be used alone or in combination.

[0043] As the coloring pigment, known coloring pigments can be used, such as inorganic pigments such as titanium oxide, zinc oxide, zirconium oxide, calcium carbonate, barium sulfate, alumina, kaolin clay, carbon black, and iron oxide, as well as organic pigments. As the rust-preventive pigment, generally known pigments can be used, such as phosphate-based rust-preventive pigments such as zinc phosphate, iron phosphate, and aluminum phosphate, molybdate-based rust-preventive pigments such as calcium molybdate, ammonium molybdate, and barium molybdate, and vanadium-based rust-preventive pigments such as vanadium oxide. Furthermore, antifoaming agents, dispersing aids, diluents for reducing the viscosity of the paint, and the like can also be used as appropriate.

[0044] The method for applying the primer is not particularly limited, and commonly used methods such as dipping, spraying, roll coating, air spraying, and airless spraying can be used. The thickness of the applied primer is preferably 1 to 30 μm, and more preferably 2 to 20 μm, as a dried film. The baking and drying conditions for the primer are not particularly limited, and can be, for example, 130 to 250° C. and a time of 1 to 300 seconds.

[0045] The top coat is not particularly limited, and any of the usual top coats for painting can be used. That is, the top coat contains a resin and, if necessary, a coloring pigment, an anti-rust pigment, etc. The resin, coloring pigment, and anti-rust pigment can be the same as those used in primers, and other optional components that can be used in primers can also be used.

[0046] The top coat may be applied in the same manner as the primer and the baking conditions may be the same as those for the primer. The top coat preferably has a dry thickness of 3 to 50 μm, more preferably 5 to 40 μm.

[0047] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0048] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0049] <Preparation of Metal Surface Treatment Agent> The compositions of the metal surface treatment agents of Examples 1 to 33 and Comparative Examples 1 to 4 are shown in Table 1. Details of the symbols shown in the columns for zirconium source (A), silane coupling agent (B), metal compound (C), and waterborne resin (D) in Table 1 are shown in Tables 2 to 5. Each metal surface treatment agent was prepared by mixing the respective components and surfactant (polyetherified product of acetylenic dialcohol) with deionized water. The nonvolatile content of each metal surface treatment agent was adjusted to 6%.

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] <Preparation of Evaluation Samples> As test materials, aluminum-zinc alloy plated steel sheets (hereinafter referred to as GL) (sheet thickness: 0.35 mm, coating weight: 50 g / m per side) were used. ２ The test pieces were degreased by spraying an alkaline degreasing agent (Fine Cleaner E6406 (manufactured by Nihon Parkerizing Co., Ltd.) dissolved in water to a mass concentration of 2%) at 60°C for 10 seconds. Thereafter, the surface of the test pieces was washed with water and dried at 115°C for 20 seconds.

[0056] The coating amount was 100 mg / m for the test material that had been degreased, washed with water, and dried. ２ Each metal surface treatment agent (each metal surface treatment agent of Examples 1 to 32 and Comparative Examples 1 to 4) was bar-coated so that the metal temperature reached 80°C, and then the bar was dried in a drying oven to prepare a test sample having a base coating.

[0057] Next, a commercially available primer paint (V-Knit #200, manufactured by Dai Nippon Toryo Co., Ltd.) was bar coated onto the test sample having the above-mentioned base coating so that the dry film thickness was 5 μm, and then the test sample was dried in a drying oven so that the metal temperature reached 200°C, thereby producing a test sample having a primer coating.

[0058] Subsequently, the test samples having the primer coating were bar-coated with a commercially available top coat paint (V-Knit #500, manufactured by Dai Nippon Toryo Co., Ltd.) to a dry film thickness of 15 μm, and then dried so that the metal temperature reached 220° C., thereby producing test samples having a primer coating, which were designated as evaluation samples No. 1 to 37.

[0059] <Evaluation Method> The evaluation samples Nos. 1 to 37 prepared above were evaluated as follows.

[0060] <Paint Adhesion> (0T Bending) In accordance with the test method of JIS-G3312, an 0T bending test was carried out on each evaluation sample at 20°C without using an inner spacer, and the state of paint film peeling after tape peeling was observed with the naked eye and evaluated according to the following evaluation criteria. <Evaluation Criteria> ◎ ＋ : No peeling ◎: Peeled area less than 10% ◯: Peeled area 10% or more but less than 50% △: Peeled area 50% or more but less than 80% ×: Peeled area 80% or more

[0061] <Paint Adhesion> (Cylindrical Processing) Each evaluation sample was set in a high-speed deep drawing tester (manufactured by Tokyo Testing Machinery Manufacturing Co., Ltd.) and subjected to a deep drawing test under the following conditions. A score of ◯ or better was considered to be pass. Mold: cylindrical, mold dimensions: blank diameter 110 mmφ, punch outer diameter 50 mmφ, die inner diameter 51.64 mmφ, punch R: 3 mm, clearance: 0.82 mm, processing speed: 40 spm, blank holding pressure: 1 kgf / cm ２ <Evaluation criteria> ◎ ＋ : No wrinkles or peeling is observed by visual inspection. ◎: Less than 5% wrinkles or peeling is observed by visual inspection. ○: 5% to less than 10% wrinkles or peeling is observed by visual inspection. △: 10% to less than 40% wrinkles or peeling is observed by visual inspection. ×: 40% or more wrinkles or peeling is observed by visual inspection.

[0062] <Corrosion resistance> (Salt spray test) A cross scratch was made with a cutter on the coating of each evaluation sample, reaching down to the metal substrate, and the salt spray test specified in JIS-Z2371 was carried out for 480 hours. Evaluation was carried out by measuring the width of the coating blister (maximum value on one side) from the cut. In addition, the width of the coating blister (maximum value) from the edge was measured as an index of edge corrosion resistance. <Evaluation criteria - cut part> ◎ ＋ : Less than 1 mm ◎: 1 mm or more and less than 2 mm 〇: 2 mm or more and less than 4 mm △: 4 mm or more and less than 6 mm ×: 6 mm or more <Evaluation criteria - end face> ◎ ＋ : Less than 3 mm ◎: 3 mm or more and less than 6 mm 〇: 6 mm or more and less than 10 mm △: 10 mm or more and less than 15 mm ×: 15 mm or more

[0063] (Combined Cycle Test) A cross scratch was made with a cutter on the coating of each evaluation sample, reaching down to the metal substrate, and the combined cycle test specified in JIS-H8502 (JASO M609-91) was carried out for 180 cycles. The width of the coating blister (maximum value on one side) from the cut was measured and evaluated according to the following evaluation criteria. In addition, as an index related to edge corrosion resistance, the width of the coating blister (maximum value) from the edge was measured and evaluated according to the following evaluation criteria. <Evaluation Criteria - Cut Part> ◎ ＋ : Less than 1 mm ◎: 1 mm or more and less than 2 mm 〇: 2 mm or more and less than 4 mm △: 4 mm or more and less than 6 mm ×: 6 mm or more <Evaluation criteria - end face> ◎ ＋ : Less than 3 mm ◎: 3 mm or more and less than 6 mm 〇: 6 mm or more and less than 10 mm △: 10 mm or more and less than 15 mm ×: 15 mm or more

[0064] The results of the paint adhesion, salt spray test and combined cycle test for each evaluation sample are shown in Table 6. Each evaluation result of "good" or better was considered to be a pass.

[0065]

[0066] The metal surface treatment agent of the present disclosure can be widely used in metal surface treatment as an alternative to chromium-based surface treatment agents. CROSS-REFERENCE TO RELATED APPLICATIONS

[0067] This application claims priority based on Japanese Patent Application No. 2023-170740, filed with the Japan Patent Office on September 29, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A metal surface treatment agent comprising at least one zirconium source (A) and at least one silane coupling agent (B), wherein the silane coupling agent (B) has an amino group, the ratio (WA / WB) of the Zr content (WA) to the Si content (WB) in the metal surface treatment agent is 0.18 to 2.34 in terms of mass ratio, and the mass ratio (NA) of Zr to the non-volatile content of the metal surface treatment agent is 1.2 mass% or more.

2. The metal surface treatment agent according to claim 1, wherein the zirconium source (A) comprises zirconium carbonate.

3. The metal surface treatment agent according to claim 1, wherein the zirconium source (A) contained in the metal surface treatment agent is zirconium carbonate alone.

4. The metal surface treatment agent according to claim 1, which contains a metal compound (C) containing at least one metal selected from the group consisting of Ti, W, V, Co, Mo, Ca, Mg and Li.

5. The metal surface treatment agent according to claim 1, which contains at least one cationic or nonionic resin (D) selected from the group consisting of urethane resins, polyvinyl alcohol resins, polyvinylpyrrolidone resins, phenolic resins and epoxy resins.

6. The metal surface treatment agent according to claim 4, which contains at least one cationic or nonionic resin (D) selected from the group consisting of urethane resins, polyvinyl alcohol resins, polyvinylpyrrolidone resins, phenolic resins and epoxy resins.

7. The metal surface treatment agent according to claim 1, wherein the silane coupling agent (B) has a primary amino group.

8. A method for producing a metal material having a surface treatment film, comprising the steps of: bringing a metal material into contact with the metal surface treatment agent according to any one of claims 1 to 7; and drying the metal surface treatment agent that has been brought into contact with the metal material to form a surface treatment film.

9. A metallic material having a surface treatment film obtained by the method for producing a metallic material according to claim 8.