Method for manufacturing surface modifiers and metallic materials for zinc phosphate conversion treatment

Abstract

This invention provides a surface conditioner that can form a formed film with a dense, crystalline zinc phosphate surface even with a short zinc phosphate formation treatment step. This invention achieves its purpose through a surface conditioner for zinc phosphate formation treatment containing a zinc-containing phosphate (A); a basic salt (B), which is a copolymer (b2) containing 2-acrylamido-2-methylpropanesulfonic acid units (b1), wherein the proportion of (b1) in the copolymer (b2) is 7.5% by mass or more and 40.0% by mass or less; and an aqueous medium (C).

Description

Technical Field

[0001] This invention relates to a surface conditioning agent used in a surface conditioning step, which is performed as a pretreatment step for forming a zinc phosphate film on a metal surface or surface. Prior Technology

[0002] Coating of metallic materials is performed to impart functions such as rust prevention or decoration. The coating of metallic materials is carried out through steps such as degreasing, surface conditioning, phosphate formation treatment, and electroplating. In the surface conditioning step, a surface conditioning agent containing, for example, zinc phosphate particles is known (see Patent Document 1).

[0003] [Previous Technical Documents] [Patent Literature] [Patent Document 1] Japanese Patent Application Publication No. 2005-264338 Summary of the Invention

[0004] [The problem the invention aims to solve] However, even when using the surface modifier in Patent Document 1, if the subsequent zinc phosphate formation treatment time is short, there is a problem that a formation film with a dense zinc phosphate crystal surface cannot be formed.

[0005] The purpose of this invention is to provide a surface conditioning agent that can form a formation film with a dense zinc phosphate crystal structure even when the zinc phosphate formation process is performed for a short time.

[0006] [Technical means to solve the problem] In order to solve the aforementioned problems, the inventors conducted in-depth research and found that if the surface of the metal material is treated with a surface conditioner containing zinc-containing phosphate (A), a basic salt of a specific copolymer (B), and an aqueous medium (C) before zinc phosphate formation treatment, the above problems can be solved.

[0007] That is, the present invention provides the following: [1] A surface conditioner for zinc phosphate formation treatment, comprising: a zinc-containing phosphate (A); a basic salt (B), which is a copolymer (b2) containing a 2-acrylamido-2-methylpropanesulfonic acid unit (b1), wherein the proportion of (b1) in the copolymer (b2) is 7.5% by mass or more and 40.0% by mass or less; and an aqueous medium (C). [2] The surface conditioner for zinc phosphate formation treatment described above [1] does not actually contain lithium montmorillonite. [3] A method for manufacturing a metallic material having a chemically formed film, comprising the following steps: The surface conditioning step is the step of bringing the zinc phosphate forming treatment surface conditioning agent as described in [1] or [2] above into contact with the metal material; and The formation treatment step is a step that comes into contact with the metal material after the aforementioned surface conditioning step, whereby the zinc phosphate formation treatment agent is brought into contact with the metal material. [4] A method for manufacturing a coated metallic material, comprising the following steps: The coating step involves forming a coating on the surface of a metal material having a chemically formed film, which is manufactured by the manufacturing method described above [3].

[0008] [Benefits of the Invention] This invention provides a surface modifier that can form a formation film with a dense, crystalline zinc phosphate surface even with a short zinc phosphate formation process. Furthermore, this surface modifier achieves excellent stability even with a high solids content. Simple Explanation of the Diagram

[0009] none Implementation

[0010] The surface modifier for zinc phosphate formation treatment according to an embodiment of the present invention comprises a zinc-containing phosphate (A); a basic salt (B), which is a copolymer (b2) containing a 2-acrylamido-2-methylpropanesulfonic acid unit (b1), wherein the proportion of (b1) in the copolymer (b2) is 7.5% by mass or more and 40.0% by mass or less; and an aqueous medium (C). By using such a surface modifier for zinc phosphate formation treatment, a dense zinc phosphate formation film can be produced even with a shorter zinc phosphate formation treatment step.

[0011] <Phosphate (A)> Zinc-containing phosphate (A) is a substance that can precipitate zinc-containing phosphate crystals. Zinc-containing phosphate can be the phosphate itself, or it can be a substance formed by the reaction of a phosphate compound with a zinc compound.

[0012] In addition to zinc, the aforementioned phosphate (A) may further contain metals such as iron, nickel, and manganese. Specific examples include phosphates containing zinc and iron, phosphates containing zinc and nickel, and phosphates containing zinc, nickel, and manganese. Furthermore, phosphate (A) may also use zinc phosphate (particles) as described in, for example, Japanese Patent Application Publication No. 2004-68149 or Japanese Patent Application Publication No. 2005-264338.

[0013] There is no particular limitation on the amount of zinc phosphate (A) contained in the surface conditioner. Phosphate (A) is usually 0.03 g / 1000 g or more, preferably 0.15 g / 1000 g or more, and usually 6.0 g / 1000 g or less. By setting the content within the above range, a good surface conditioning effect can be obtained.

[0014] <Basic salt (B) of copolymer (b2) (hereinafter also referred to as compound (B))> The copolymer (b2) contains 2-acrylamido-2-methylpropanesulfonic acid units (b1). Furthermore, the proportion of (b1) in the copolymer (b2) is 7.5% by mass or more and 40.0% by mass or less. Preferably, it is 9.0% by mass or more and 40.0% by mass or less.

[0015] There are no particular limitations on the units that form the copolymer (b2) together with unit (b1), such as acrylic acid units, methacrylic acid units, maleic acid units, fumaric acid units, adipic acid units, styrene units, etc., and compound (B) contains one or more of these units.

[0016] There are no particular limitations on the manufacturing method of compound (B). Taking the manufacturing method of sodium compound of copolymer (b2) formed by acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid (b1) as an example, it can be obtained by copolymerizing acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid (b1) and then neutralizing the obtained copolymer with an alkaline component containing sodium.

[0017] Examples of alkaline components include hydroxides or carbonates of alkali metals such as sodium and potassium; hydroxides or carbonates of alkaline earth metals; and organic amines such as ammonia, monoethanolamine, diethanolamine, and triethanolamine, with sodium hydroxide, potassium hydroxide, and ammonia being preferred. These components can be used for neutralization before copolymerization of 2-acrylamido-2-methylpropanesulfonic acid (b1), or after the copolymer (b2) is produced.

[0018] When the proportion of (b1) in copolymer (b2) is less than 7.5% by mass, the phosphate (A) contained in the surface conditioner exhibits poor dispersibility when forming a high concentration. Prolonged standing time leads to phosphate (A) precipitation, resulting in poor time stability. Furthermore, even when the mass ratio of (b1) exceeds 40.0% by mass, the phosphate (A) contained in the surface conditioner exhibits poor dispersibility when forming a high concentration, leading to phosphate (A) precipitation when standing time is prolonged. Moreover, it becomes difficult to form a zinc phosphate formation film using a short zinc phosphate formation treatment. Additionally, when the mass ratio of (b1) exceeds 40.0% by mass, zinc phosphate crystals sometimes form columnar crystals, failing to form a dense surface. High concentration refers to a concentration of compound (B) in the surface conditioner of 5 g / 1000 g or more, preferably 10 g / 1000 g or more.

[0019] The number average molecular weight of the copolymer (b2) is preferably 100 or more, more preferably 1000 or more, and preferably 30000 or less, more preferably 20000 or less. If the number average molecular weight is within the above range, the component (A) contained in the surface conditioner has good dispersibility and improved time stability at high concentrations.

[0020] There are no particular restrictions on the amount of compound (B) contained in the surface conditioner. Compound (B) is typically (when used) above 0.001 g / 1000 g and below 0.2 g / 1000 g. However, because its time stability is excellent even at high concentrations, it can be stored at concentrations of 5 g / 1000 g or above, 10 g / 1000 g or below, or 50 g / 1000 g.

[0021] <Aqueous Medium (C)> Aqueous medium (C) is not particularly limited as long as it is water or a mixture of water and a water-miscible organic solvent (containing more than 50% water by volume). Water-miscible organic solvent is not particularly limited as long as it is miscible with water; examples 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, 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 or more of these water-miscible organic solvents may be mixed with water.

[0022] <Other Ingredients> The surface conditioner may consist solely of the above-mentioned components, or, without impairing the effectiveness of the present invention, may contain other components such as water-soluble or water-dispersible resins, metal compounds, rust inhibitors, crosslinking agents, antibacterial / mildew inhibitors, defoamers, surfactants, and other conventional additives. Furthermore, the surface conditioner is preferably lithium-free montmorillonite. The absence of lithium-free montmorillonite prevents an increase in fluorosilicic acid (hydrofluoric acid) compounds in the zinc phosphate conversion agent, thus preventing a decrease in hydrofluoric acid and inhibiting the slowdown of the etching reaction.

[0023] <pH value of surface conditioner> The pH value of the surface conditioner is not particularly limited, but it is preferably 8.0 or higher, more preferably 9.0 or higher; furthermore, it is preferably 11.0 or lower, more preferably 10.5 or lower. If the pH value of the surface conditioner is within the above range, the effects of the present invention are more easily achieved, and therefore preferred. The pH value of the surface conditioner can be measured using a commercially available pH meter. The pH meter can be either stationary or handheld, and the aforementioned pH value can be measured after calibrating the pH meter with a pH calibration solution.

[0024] <Method for manufacturing surface conditioners> The surface modifier is obtained by blending a zinc-containing phosphate (A) and a basic salt (B) of a copolymer (b2) into an aqueous medium (C). Because the surface modifier exhibits excellent time stability even when containing a high concentration of the basic salt (B), it can be manufactured by diluting the surface modifier with an aqueous medium before use, after obtaining a surface modifier containing a high concentration of the basic salt (B).

[0025] <Manufacturing Method of Metallic Materials with Formed Coating> The present invention discloses a method for manufacturing a metallic material having a formation film, comprising the following steps: a surface conditioning step, which is a step of contacting the above-mentioned zinc phosphate formation treatment surface conditioning agent with the metallic material; and a formation treatment step, which is a step of contacting the zinc phosphate formation treatment agent with the metallic material after the surface conditioning step.

[0026] Surface conditioning with surface modifiers targets metallic surfaces. The material being treated can be metallic, or it can be a material whose surface has partially or entirely exposed metallic material. In other words, any material containing a metallic surface is a target for surface conditioning. Examples of materials with partially or entirely exposed metallic material include composites of resin and metal, and composites of glass and metal.

[0027] There are no particular restrictions on the types of metallic materials. Examples include iron and steel (such as cold-rolled steel plates, hot-rolled steel plates, black sheet metal, pickled steel plates, high-tensile steel plates, tool steel, alloy tool steel, spheroidal graphite cast iron, gray cast iron, etc.); coated materials, such as galvanized materials (e.g., electro-galvanizing, hot-dip galvanizing, aluminum-zinc plating, zinc-nickel plating, zinc-cobalt plating, vapor-galvanizing, etc.), zinc alloy materials (e.g., alloyed hot-dip galvanizing, Zn-Al alloy plating, Zn-Al-Mg alloy plating, electro-galvanized alloy plating, etc.), aluminum plating, nickel plating, tin plating, chromium plating, chromium alloy plating (e.g., Cr-Ni alloy plating, etc.); aluminum or aluminum alloy materials (e.g., 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, aluminum castings, aluminum alloy castings, die-casting materials, etc.); copper or copper alloy materials; titanium or titanium alloy materials; magnesium or magnesium alloy materials, etc.

[0028] Methods for bringing various agents into contact with metallic materials include conventional methods such as immersion (including electrolytic treatment), spraying, roller dipping, and brushing, or combinations thereof. The contact temperature is typically above 10°C and below 60°C, preferably above 30°C and below 45°C, but there are no particular limitations. Furthermore, the contact time can be carried out under conventional conditions, such as above 5 seconds and below 600 seconds, preferably above 10 seconds and below 300 seconds.

[0029] In addition, a degreasing process, known as degreasing, may be included before the surface conditioning step to remove oil and deposits from the metal surface. There are no particular limitations on the degreasing method; conventional methods can be used. Water rinsing may or may not be performed after the degreasing step.

[0030] The formation treatment step is preferably performed immediately after the surface conditioning step, without rinsing or drying. Commonly known zinc phosphate formation treatment agents can be used.

[0031] Following the zinc phosphate formation treatment described above, washing and / or drying may be performed as needed. Furthermore, after the zinc phosphate formation treatment, formation treatment steps for forming other formation films may also be performed. Examples of formation treatment steps for forming other formation films include zirconium formation, titanium formation, hafnium formation, vanadium formation, and other various formation treatment steps. The various formation agents used in these formation treatment steps can be those already known, and the formation conditions can also be those already known. Additionally, after other formation treatment steps, washing and / or drying may be performed as needed.

[0032] <Manufacturing Method of Metallic Materials with Coating> The present invention discloses a method for manufacturing a coated metallic material, comprising a coating step of forming a coating on the surface of a metallic material having a zinc phosphate coating. The coating method for forming the coating is not particularly limited, and conventional methods can be used, such as roller coating, electroplating (e.g., cationic electroplating), spray coating, thermal spraying, airless spraying, electrostatic coating (e.g., electrostatic powder coating), roller coating, curtain coating, brush coating, rod coating, and flow immersion coating. Furthermore, after the coating step, a drying step (including a baking step and a hardening step) can be performed to dry the coating on the surface of the coated metallic material.

[0033] Examples of the aforementioned coatings include oil-based coatings, cellulose derivative coatings, phenolic resin coatings, alkyd resin coatings, amino alkyd resin coatings, urea resin coatings, unsaturated resin coatings, vinyl resin coatings, acrylic resin coatings, epoxy resin coatings, polyurethane resin coatings, silicone resin coatings, fluoropolymer coatings, rust-preventive paints, antifouling coatings, powder coatings, cationic electrocoating coatings, anionic electrocoating coatings, water-based coatings, and solvent-based coatings, among other commonly known coatings. Furthermore, the coating process may involve using the same or different coatings, and may involve a single coat or two or more coats. The drying process is the treatment to allow the coated coating to dry and harden. Examples of drying methods include natural drying, reduced pressure drying, convective heat drying (e.g., natural convection heat drying, forced convection heat drying), radiation drying (e.g., near-infrared drying, far-infrared drying), ultraviolet curing drying, electron beam curing drying, airflow curing (VAPOCURE), and baking drying. In addition, one or more of these drying methods may be implemented, or a combination of two or more may be used.

[0034] The aforementioned cationic electrocoating can be performed using conventional methods. Examples include using a cationic electrocoating paint containing an amino addition epoxy resin and a capped polyisocyanate curing agent as a curing component, and then immersing a metal material with a formed film into this paint. Cationic electrocoating is performed, for example, by maintaining the paint temperature at a specific temperature, and while the paint is stirred, applying a voltage to the cathode direction of the metal material with the formed film using a rectifier. For the metal material thus subjected to cationic electrocoating, a coating film can be formed on the formed film by washing with water and baking. Baking is performed for a fixed time within a specific temperature range. Specifically, it is performed at 170°C for 20 minutes. Furthermore, when using a cationic electrocoating method with a cationic electrocoating paint, it is preferable to control the sodium ion concentration in the treatment agents used in, for example, the degreasing step, pretreatment step, and various formation treatment steps, to be less than 500 ppm by mass.

[0035] Coating methods using powder coatings, such as spray coating, electrostatic powder coating, and flow impregnation, can be conventionally applied. Examples of powder coatings include those containing polyester resins and end-capped isocyanate curing agents, β-hydroxyalkylamide curing agents (see, for example, Japanese Patent Application Publication No. 2011-88083), or triglycidyl isocyanurate. Baking is performed for a fixed time within a specific temperature range. Specifically, it is performed at 150~250°C for 20 minutes.

[0036] Coating methods using the aforementioned solvents, such as spray coating, electrostatic coating, and rod coating, are applicable to conventional methods. Examples of solvent-based coatings include those containing resins such as melamine resin, acrylic resin, polyurethane resin, and polyester resin, as well as organic solvents such as diluents. Baking is performed for a fixed time within a specific temperature range. Specifically, it is performed at 130°C for 20 minutes.

[0037] The coating obtained through the coating process can be a single layer or multiple layers. In the case of multiple layers, the paint used to form various coatings, the coating method using the paint, and the drying method of the coated metal material can be the same or different.

[0038] [Example] The present invention will now be described in more detail through the disclosure of embodiments, but the present invention is not limited to these embodiments. Furthermore, in the embodiments, unless otherwise stated, "parts" and "%" refer to "parts by mass" and "% by mass".

[0039] <Preparation of copolymer (b2)> Referring to conventional methods (e.g., Japanese Patent Application Publication No. 2019-31689), polymers and copolymers 1 to 10 with the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid unit (b1) to copolymer (b2) as shown in Table 1 were prepared. Furthermore, the following compounds were generated: polymerized acrylic acid to produce a polymer; copolymerized 2-acrylamide-2-methylpropanesulfonic acid with acrylic acid to produce copolymers 1 to 2, 4 to 5, 7 to 9, and 12 to 14; copolymerized 2-acrylamide-2-methylpropanesulfonic acid with methyl acrylate to produce copolymer 3; copolymerized 2-acrylamide-2-methylpropanesulfonic acid with maleic acid to produce copolymers 6 and 10; and copolymerized acrylic acid sulfonic acid with acrylic acid to produce copolymer 11.

[0040] <Preparation of Basic Salts (B) of Polymers and Copolymers> The prepared polymers and copolymers 1-10 were adjusted to pH 7.0 with sodium hydroxide to obtain an aqueous solution of the sodium compounds of the polymers and copolymers. At this point, the sodium salt content of the polymers and copolymers in the aforementioned aqueous solution was adjusted to 40.0% by mass.

[0041] The mass ratio of unit (b1) in the copolymer was calculated by measuring the area values ​​of unit (b1) and specific protons derived from acrylic acid units in the sodium compound aqueous solution of the above polymer and copolymer using nuclear magnetic resonance spectroscopy (NMR), calculating the relative molar ratio from the area values, multiplying the molar ratio by the molecular weight of the acid of each unit (b1) and (b2) to calculate the mass, and then substituting the calculated mass into the formula [[(b1) / (b2)]×100]. Measurement conditions for 1H-NMR Measuring machine: JNM-ECX400 (manufactured by Nippon Electronics) Probe: 40TH5AT / FG2D-5mm (Broadband Gradient Tunable Probe) Measurement of nuclear species: 1H Measurement solvent: heavy water Total number of times: 16

[0042] In addition, the quantity average molecular weight of polymers and copolymers was determined by GPC (gel permeation chromatography) analysis, and then the equivalent average molecular weight of polyethylene glycol was obtained.

[0043] [Table 1]

[0044] Preparation of surface conditioner (high concentration) for zinc phosphate formation treatment Zinc phosphate was prepared as a zinc-containing phosphate (A). Then, zinc phosphate was mixed with water in the proportions shown in Table 2 to prepare high-concentration surface conditioners 1-44. In addition, surface conditioner 35 contained an antifoaming agent and a mildew inhibitor, and surface conditioner 36 contained zinc manganese phosphate instead of zinc phosphate.

[0045] [Table 2]

[0046] <Stability of high-concentration surface conditioners> The surface conditioning agents of Examples 1-38 and Comparative Examples 1-6 were sealed in containers. After preparation, they were placed in a cool, dark place (25°C). After standing for two months, the appearance was checked, and those that did not separate were rated as "○" and those that separated were rated as "╳".

[0047] [Table 3]

[0048] <Preparation of surface modifiers for zinc phosphate conversion treatment> After preparing the surface conditioning agents of Examples 1-38 and Comparative Examples 1-6, they were left to stand in a cool place for 3 months. 0.5g of each agent was then taken and added to deionized water. 0.25% by mass sodium hydroxide aqueous solution was added dropwise to bring the pH value to 9.0. The pH value was then adjusted to 1000g to prepare a surface conditioning agent suitable for metal materials.

[0049] <Preparation of Metallic Materials> (Metallic materials) The metal material is prepared by cutting 1mm thick cold-rolled steel sheet, 590MPa grade high-strength steel (manufactured by PALTEK Corporation), and black sheet material (iron-based material manufactured by the same company) into dimensions of 150mm long side × 75mm short side.

[0050] (Defatting steps) The black leather was pre-degreased and wiped with a soft cloth. Next, 100L of degreasing solution (manufactured by Pakase Sei Co., Ltd., Japan, Fine Cleaner E2082, 20g / L aqueous solution) was prepared, its temperature adjusted to 43°C, and carbon dioxide gas was sprayed to adjust the pH to 10.5. The adjusted degreasing solution was sprayed onto the black leather for 2 minutes, followed by spraying tap water for 30 seconds, and then spraying deionized water for 30 seconds. Finally, air was sprayed onto the black leather to remove moisture adhering to its surface and to ensure the oxide film did not peel off.

[0051] (Surface conditioning steps, zinc phosphate formation treatment steps) Cold-rolled steel sheets, high-tensile steel, and degreased and washed black leather were immersed in the surface conditioning agents of Examples 1-38 and Comparative Examples 1-6 at 25°C for 30 seconds. Next, 48 g / L of zinc phosphate forming agent (Palbond SX35 bath additive manufactured by Pakase Sei Co., Ltd., Japan), 17 g / L of additive 4856 (manufactured by the same company), 5 g / L of additive 4813 (manufactured by the same company), and accelerator 131 (manufactured by the same company) were added, followed by 2.5% by mass of sodium hydroxide, to prepare 10 L of zinc phosphate forming agent, which was then heated to 35°C. At this point, the free acidity was 0.6 pt, the total acidity was 23 pt, and the accelerator concentration was 3.0 pt. Each metal material was immersed in this zinc phosphate forming agent for the time specified in Table 4. The amount of zinc phosphate forming film adhering to the metal material was set at 2 g / m². Furthermore, since the zinc phosphate forming process reduces the composition of the forming agent, this component was appropriately replenished.

[0052] (Drying step) After zinc phosphate formation treatment according to the times shown in Table 4, the surface of the metal material was sprayed with tap water for 30 seconds, followed by spraying with deionized water for 30 seconds, and then air was blown to remove the moisture from the metal. Six sheets each of cold-rolled steel sheet, high-tensile steel, and black sheet were prepared.

[0053] Evaluation of metallic materials with zinc phosphate conversion coating (1) Appearance The appearance of the zinc phosphate coating on the metallic materials was visually inspected to confirm its shape. The appearance was evaluated based on the presence or absence of metallic luster. The results are shown in Table 4.

[0054] (2) Formation time of zinc phosphate coating The adhesion amount of the zinc phosphate coating on the metal material was set at 2 g / m2, and the adhesion amount of the zinc phosphate coating was measured in the following manner: The amount of zinc phosphate deposited was calculated by measuring the weight of three pieces of metal material with zinc phosphate coating. The weight of the metal material after the formation treatment was measured (denoted as W1 [g]), and then the treated metal material was immersed in a chromic acid aqueous solution at 75°C. The weight of the metal material after the zinc phosphate coating was removed was then measured (denoted as W2 [g]). The decrease in weight was divided by the surface area of ​​the metal material, and the resulting value was taken as the amount of zinc phosphate coating (g / m2). Whether this weight achieves the target adhesion amount of 2g / m2 is determined by setting the zinc phosphate formation treatment time to 30 seconds, 45 seconds, 60 seconds, 75 seconds, 90 seconds, and 120 seconds to form a formation film on the metal material, and measuring the adhesion amount of the formation film at each treatment time to confirm the formation treatment time required to achieve the target adhesion amount.

[0055] [Table 4]

[0056] [Industrial applicability] Surface modifiers are applicable to various metal materials used in automobile bodies, home appliances, and other products. Furthermore, this invention enables the production of dense zinc phosphate films of the same quality as prior art in a short time, even for materials that are difficult to chemically process. In other words, it improves the energy efficiency required to manufacture the processed materials. In addition, it helps save space in zinc phosphate chemical processing equipment during repairs, reconstructions, and the construction of new production lines, thus enabling efficient space utilization. Furthermore, although the present invention has been described in detail with reference to specific embodiments, those skilled in the art to which this invention pertains can make various alterations and modifications without departing from the spirit and scope of the invention.

[0057] none

[0058] none

Claims

1. A surface conditioner for zinc phosphate formation treatment, comprising: a zinc-containing phosphate (A); a basic salt (B), which is a copolymer (b2) containing a 2-acrylamido-2-methylpropanesulfonic acid unit (b1), wherein the proportion of (b1) in the copolymer (b2) is 7.5% by mass or more and 40.0% by mass or less; and an aqueous medium (C).

2. The zinc phosphate formation treatment surface modifier as described in claim 1 is substantially free of lithium montmorillonite.

3. A method for manufacturing a metallic material having a formation film, comprising the following steps: a surface conditioning step, which is a step of contacting the metallic material with a zinc phosphate formation treatment surface conditioning agent as described in claim 1 or 2; and a formation treatment step, which is a step of contacting the metallic material with a zinc phosphate formation treatment agent after the aforementioned surface conditioning step.

4. A method for manufacturing a metal material having a coating film, comprising the following steps: a coating step, wherein a coating film is formed on the surface or surface of a metal material having a chemically formed film produced by the manufacturing method described in claim 3.

Images