TWI447264B - Surface-treating agent for metallic material - Google Patents

Description

Metal material surface treatment agent

The present invention relates to a surface treatment agent for a metal material, a surface treatment method using the surface treatment agent for the metal material, and a surface treatment metal material having a film.

In order to obtain corrosion resistance or coating properties, the metal-based material is subjected to a surface treatment. That is, it is extremely important to obtain an effect of suppressing corrosion of the metal by surface treatment, or not peeling off the coating film at the time of coating, or not causing corrosion from the portion even if the coating film is peeled off. Conventionally, as a surface treatment of a metal-based material, a chromate treatment which precipitates a phosphate of a metal phosphate crystal or forms a film containing hexavalent chromium is used.

In the phosphate treatment, the metal material is first brought into contact with an aqueous solution containing phosphoric acid and metal ions. At this time, the metal is dissolved by the acid, and hydrogen is consumed at the interface of the metal material by the dissolution reaction to cause an increase in pH. The phosphate metal salt which is prevented from being dissolved by the pH rise is deposited on the surface of the metal material to form a phosphate film. Since the phosphate film is deposited on the surface of the metal material, the adhesion to the metal material is excellent. Further, since the film formed by the formation of the fine crystals has an anchoring effect by the fine unevenness, it is excellent in adhesion to the applied coating film. Therefore, the current phosphate treatment is also widely used as a substrate for coating, which is an excellent surface treatment.

However, since it is derived from a treatment in which a metal is brought into contact with an acidic aqueous solution containing phosphoric acid to cause a dissolution reaction, that is, a so-called reactive surface treatment, a component containing a treatment liquid containing phosphoric acid depending on the kind of the metal material may follow The problem of change. Further, since the phosphate which cannot be deposited on the surface of the metal material floats on the treatment liquid as the slag, it is necessary to remove it. Further, the contact conditions (temperature, time, and the like) between the aqueous solution and the metal material are also required to be appropriately changed. Further, there is a problem that a water washing step (production of waste water) must be performed after the surface treatment. In addition, it cannot be applied to materials such as stainless steel that are not reactive.

The same type of reaction as phosphate is also used in the chromate treatment, and a coated chromate treatment in which only an aqueous solution is applied and then dried is widely known. The coating type chromate treatment is a simple method in which only an aqueous solution containing hexavalent chromium is applied to the surface of a metal material and then dried. Therefore, the surface washing treatment does not require a water washing step and is a closed system without waste water, so this method is often used in surface treatment of sheet/coil. In addition, the coating type chromate film is in the form of a soluble hexavalent chromium (chromic acid) in a film skeleton based on the polymerization of trivalent chromium, and is protected by a film of a trivalent chromium substrate. It has excellent corrosion resistance to metal materials by oxidation with hexavalent chromium (passivation, self-healing). Further, in the case of the substrate for coating, it is known that Ni is subjected to micro-substitution plating as a pretreatment so that the coating film is not easily peeled off. One of the reasons for this is that the substitution plating increases the adhesion between the chromate film and the metal surface.

The preferred form of the surface treatment of the metal material is excellent in adhesion to the surface of the metal material, and the film component is highly polymerized. Further, a soluble corrosion inhibitor is present in the film to form a corrosion inhibitor which can be retained for a long period of time. Membrane. In the coating type chromate treatment, a film having the above characteristics is formed. However, the coating film formed by the coating type chromate treatment contains hexavalent chromium, and the hexavalent chromium is precipitated in contact with moisture, so that it is concerned from the viewpoint of environmental surface and safety. Therefore, various studies have been conducted to suppress the hexavalent chromium precipitated from the chromate film.

However, it has recently been tended to be able to prevent the presence of hexavalent chromium, and many chromate-free treatments without hexavalent chromium are currently being developed.

As the chromate-free treatment, Patent Document 1 discloses a steel sheet in which a film formed of a P compound, a Si compound, and a tetravalent vanadium compound is formed. However, in this technique, the adhesion to the surface of the metal material cannot be sufficiently ensured, and sufficient corrosion resistance cannot be obtained.

Patent Document 2 discloses a treatment liquid containing a decane coupling agent, a specific resin, four or more metal complexes of F, and metal compounds (Mn, Co, Zn, Mg, Ni, Ti, V, Zr). However, this technique cannot sufficiently ensure the adhesion to the surface of the metal material, and sufficient corrosion resistance cannot be obtained.

Patent Document 3 discloses water dispersibility of core-shell composite particles obtained by polymerization operation of colloidal cerium oxide, organoalkoxy decane, and ethylene monomer having an ethylenically unsaturated group. Things. However, more than 80% of the particles are colloidal cerium oxide. This particle is a technique for stably mixing a resin, and a film cannot be formed by using it alone, and corrosion resistance cannot be obtained.

Patent Document 4 discloses a technique of using a composition containing a decane and a metal nip. The metal clamp acts as a dissolving metal ion (especially in a cationic state) and also acts in combination with the surface of the metallic material. However, in this technique, since metal ions are clamped, metal ions are easily dissolved, and as a result, precipitation of such ions cannot be sufficiently suppressed, and long-term corrosion resistance cannot be obtained.

Patent Document 5 discloses that a decane coupling agent is contained in an amount of 0.01 to 100 g/L, cerium oxide is 0.05 to 100 g/L, Zr is 0.01 to 50 g/L, and/or Ti is 0.01 to 50 g/L, and a sulfur-containing carboxyl compound is 0.01 to 100 g/L. A treatment liquid of 0.1 to 100 g/L of an acrylic resin. This technique is excellent in adhesion and good in coating property, but the corrosion resistance in the absence of coating is insufficient. Furthermore, since the treatment liquid gels over time, it cannot be used in industry.

Patent Document 6 discloses a technique using a carboxyl group-containing polyurethane resin, a decane coupling agent, cerium oxide, and scaly cerium oxide.

Patent Document 7 discloses a technique using a urethane resin, a decane coupling agent, and cerium oxide. The techniques disclosed in Patent Documents 6 and 7 cannot sufficiently ensure the adhesion to the surface of the metal material. Further, since cerium oxide cannot be sufficiently fixed in the film, sufficient corrosion resistance cannot be obtained.

Patent Document 8 discloses an organic resin film which forms a film containing an organic resin and a decane coupling agent in the lower layer and a thiocarboxy group in the upper layer. This technology relates to the lower layer of the two-layer process, and achieves the purpose for the first time by combining with the upper layer. In the case of a separate film, the adhesion to the metal material and the corrosion resistance are still not obtained.

Patent Document 9 discloses a technique of using a vanadium compound and Zr, Ti, Mo, W, Mn, and Ce. However, sufficient adhesion between the film formed in the technique and the metal material cannot be obtained, and precipitation of the metal compound cannot be suppressed.

Patent Document 10 discloses a technique using a decane coupling agent, a hydrazine sol, or an aqueous organic resin. In this technique, the decane coupling agent is bonded to the surface of the ceria, so that the ceria component can be fixed, but the precipitation of the metal compound cannot be suppressed.

As described above, neither of the methods can obtain a surface-treated steel sheet instead of the chromate film. Therefore, it is strongly desired to develop a surface treatment agent which comprehensively satisfies the characteristics of corrosion resistance and top coatability, in particular, The adhesion between the formed film and the metal material can be improved, and a surface-treated steel sheet which suppresses corrosion of the metal material can be produced.

Patent Document 1 Japanese Patent Laid-Open Publication No. 2005-48199

Patent Document 2 Japanese Patent Laid-Open Publication No. 2005-120469

Patent Document 3 Japanese Patent No. 3818689

Patent Document 4 Japanese Patent Special Publication No. 2006-519307

Patent Document 5 Japanese Patent Laid-Open Publication No. 2001-316845

Patent Document 6 Japanese Patent Laid-Open Publication No. 2005-178213

Patent Document 7 Japanese Patent Laid-Open Publication No. 2005-200757

Patent Document 8 Japanese Patent No. 3722658

Patent Document 9 Japanese Patent Laid-Open Publication No. 2002-30460

Patent Document 10 Japanese Patent Laid-Open Publication No. 2001-98215

An object of the present invention is to provide a surface treatment agent for a metal material and a surface treatment method using the surface treatment agent for the metal material. The surface treatment agent for a metal material has properties such as corrosion resistance and top coatability in a film formed by a surface treatment of a coating type, and particularly, the adhesion between the formed film and the surface of the metal material is excellent. And a component that functions as a corrosion inhibitor of a metal material can be fixed in the film.

The present inventors have focused on the properties of the organoalkoxydecane, and as a result of diligent research, it has been found that the above treatment can be solved by using a treatment agent containing a predetermined compound and an amount of an alcohol formed by hydrolysis of an organoalkoxysilane. Question.

That is, the present invention provides the following (1) to (9).

(1) A surface treatment agent for a metal material comprising: a phthalic acid compound (A); an organoalkoxy decane (B); and a metal compound (C) containing a component selected from the group consisting of Zr, Ti, Co, Fe, and V. At least one metal element of the group consisting of Ce, Mo, Mn, Mg, Al, Ni, Ca, W, Nb, Cr, and Zn; and the compound (D) is selected from the group consisting of a phosphoric acid compound and a fluorine compound. At least one of the group; water (E); alcohol (F), which is produced by hydrolysis of the above organoalkoxydecane (B); molar concentration of the above alcohol (F) in the treating agent (mol) /L) (C _F1 ) ratio of molar concentration (mol/L) (C _F2 ) of the alcohol formed in the treatment agent when all alkoxy groups contained in the above organoalkoxydecane (B) are hydrolyzed (C _F1 /C _F2 ), adjusted in the range of 0.05 to 0.9.

(2) A surface treatment agent for a metal material according to (1), wherein a mass ratio (C/F) of the above alcohol (F) to the metal compound (C) is 0.01 to 50.

(3) A surface treatment agent for a metal material according to (1) or (2), wherein a mass ratio (D/F) of the above alcohol (F) to the above compound (D) is from 0.01 to 25.

(4) A surface treatment agent for a metal material according to any one of (1) to (3), wherein a mass ratio (A/B) of the above-mentioned citric acid compound (A) to the above organoalkoxy decane (B) is 0.01 ～ 3.0; a mass ratio (C/(A+B)) of the total mass (A+B) of the above-mentioned citric acid compound (A) and the above organoalkoxydecane (B) to the above metal compound (C) is 0.01 to 2.0 The mass ratio (D/(A+B)) of the total mass (A+B) of the above-mentioned citric acid compound (A) and the above organoalkoxydecane (B) to the above compound (D) is from 0.01 to 1.5.

(5) A surface treatment agent for a metal material according to any one of (1) to (4), wherein the organoalkoxydecane (B) has an amine group and/or an epoxy group.

(6) The surface treatment agent for a metal material according to any one of (1) to (5), further comprising a compound (G); wherein the compound (G) is selected from the group consisting of a water-soluble polymer and an aqueous emulsion resin. At least one of them.

(7) A surface treatment agent for a metal material according to (6), wherein a mass ratio of the total mass (A+B) of the above-mentioned citric acid compound (A) and the above organoalkoxydecane (B) to the above compound (G) (G/(A+B)) is from 0.01 to 0.3.

(8) A surface treatment method for a metal material, which is applied to a surface of a metal material by applying a surface treatment agent for any of the metal materials (1) to (7), and heating and drying to form a film amount on the surface of the metal material. The film is 2 to 1000 mg/m ² in terms of Si adhesion amount.

(9) A surface-treated metal material having a film on its surface, which is obtained by a surface treatment method of a metal material of (8).

The present invention provides a surface treatment agent for a metal material, and a surface treatment method using the surface treatment agent for the metal material. The surface treatment agent for a metal material has properties such as corrosion resistance and top coatability in a film formed by a surface treatment of a coating type, and particularly, the adhesion between the formed film and the surface of the metal material is excellent. And a component that functions as a corrosion inhibitor of a metal material can be fixed in the film.

Hereinafter, the surface treatment agent for a metal material of the present invention and a surface treatment method using the surface treatment agent for the metal material will be described.

First, a surface treatment agent for a metal material will be described in detail.

<Surface treatment agent for metal materials>

A surface treatment agent for a metal material according to the present invention, which comprises: a phthalic acid compound (A); an organoalkoxy decane (B); and a metal compound (C) containing a component selected from the group consisting of Zr, Ti, Co, Fe, V, Ce At least one metal element of the group consisting of Mo, Mn, Mg, Al, Ni, Ca, W, Nb, Cr, and Zn; and the compound (D) is selected from the group consisting of a phosphoric acid compound and a fluorine compound At least one of them; water (E); alcohol (F), which is produced by hydrolysis of organoalkoxydecane (B). Further, the alcohol (F) in the treating agent has a molar concentration (mol/L) (C _F1 ) and an alcohol generated by hydrolysis of all alkoxy groups contained in the organoalkoxydecane (B) to the treating agent. The ratio of molar concentration (mol/L) (C _F2 ) (C _F1 /C _F2 ) in the range is adjusted to be in the range of 0.05 to 0.9.

First, various components constituting the surface treatment agent for a metal material will be described.

<Citrate compound (A)>

The surface treatment agent for a metal material of the present invention contains a phthalic acid compound (A). By using a phthalic acid compound, it is possible to form a film excellent in properties such as corrosion resistance, top coatability, heat resistance, weldability, and continuous processability.

The citric acid compound has ruthenium and oxygen as main constituent components, and the type thereof is not particularly limited. For example, an alkaline citrate such as sodium citrate, potassium citrate or lithium ruthenate; a colloid obtained by a method of gelation or the like by removing the sodium, potassium or lithium by ion exchange; Cerium dioxide or liquid phase cerium oxide; cerium chloride is oxidized in air to obtain a gas phase cerium oxide, which is dispersed in water; and a hydrolyzate of alkoxy decane. Among them, colloidal cerium oxide and liquid phase cerium oxide are preferred from the viewpoint of further excellent performance of the obtained film.

Examples of the liquid phase cerium oxide include SNOWTEX C, SNOWTEX CS, SNOWTEX CM, SNOWTEX O, SNOWTEX OS, SNOWTEX OM, SNOWTEX NS, SNOWTEX N, SNOWTEX NM, SNOWTEX S, SNOWTEX 20, SNOWTEX 30, SNOWTEX 40, ADELAIDE. AT-20N, ADELAIDE AT-20A, ADELAIDE AT-20Q, etc., in addition to SNOWTEX UP, SNOWTEX OUP, SNOWTEX PS-S, SNOWTEX PS-SO, SNOWTEX PS-M, SNOWTEX PS-MO processed into special chains , SNOWTEX PS-L, SNOWTEX PS-LO, etc.

Further, as the fine particle cerium dioxide called gas phase cerium oxide, AEROSIL 50, AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL 380, AEROSIL TT600, AEROSIL MOX80, AEROSIL MOX170, etc. may be mentioned, and it may be dispersed in water. By.

The content of the phthalic acid compound (A) in the surface treatment agent for a metal material is not particularly limited, and the corrosion resistance, top coatability, heat resistance, weldability, and continuous workability of the obtained film are more excellent. The total solid content in the treatment agent is preferably from 0.1 to 70% by mass, more preferably from 1 to 50% by mass. In addition, the total solid content in the treatment agent means a solid component constituting the film described later, and does not contain a solvent or the like.

<Organic alkoxydecane (B)>

The surface treatment agent for a metal material of the present invention contains an organoalkoxydecane (B). By using the organoalkoxydecane (B) in combination with the above-mentioned citric acid compound (A), a ruthenium oxide bond is formed between the phthalic acid compound (A) and the organoalkoxy decane (B) to form heat resistance. Membrane. It is presumed that it is a cause of improving the corrosion resistance, top coatability, heat resistance, weldability, continuous workability, grounding property, and adhesion to the surface of the metal material.

The organoalkoxydecane used in the present invention is not particularly limited, and examples thereof include tetramethoxynonane, tetraethoxydecane, trimethylmethoxydecane, trimethylethoxysilane, and dimethyldiene. Methoxy decane, dimethyl diethoxy decane, methyl triethoxy decane, cyclohexyl methyl dimethoxy decane, n-hexyl trimethoxy decane, diphenyl dimethoxy decane, diphenyl Diethoxy decane, phenyl trimethoxy decane, phenyl triethoxy decane, decyl trimethoxy decane, octadecyl trimethoxy decane, octadecyl triethoxy decane, isobutyl trimethyl Oxydecane, ethylene trichlorodecane, ethylene trimethoxy decane, ethylene triethoxy decane, β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, γ-glycidoxypropyl Methyl diethoxy decane, γ-glycidoxypropyl triethoxy decane, N-β (amine ethyl) γ-aminopropyl methyl dimethoxy decane, γ-aminopropyl trimethyl Oxydecane, γ-aminopropyltriethoxydecane, γ-methylpropenyloxypropylmethyldimethoxydecane, γ-methylpropenyloxypropylmethyldi Oxy decane, γ-thiol propyl methyl dimethoxy decane, p-styrene trimethoxy decane, γ-acryloxypropyl trimethoxy decane, N-phenyl-γ-aminopropyl Trimethoxy decane, γ-ureidopropyl triethoxy decane, γ-chloropropyltrimethoxy decane, bis(triethoxy propyl propyl) tetrasulfide, γ-isocyanate propyl triethoxy decane , γ-triethoxyindolyl-N-(1,3-dimethyl-butylene)propylamine, N-(vinylbenzylamine)-β-aminoethyl-γ-aminopropyltrimethoxydecane Wait.

Among them, since the concentration of the alcohol is easily adjusted, it is preferably a trialkoxysilane having 3 mol of the active alkoxy group.

Further, the organoalkoxydecane (B) preferably has at least one functional group selected from the group consisting of an amine group and an epoxy group. It is presumed that the organoalkoxydecane (B) has such a functional group, and promotes the formation of a siloxane coupling between the above citric acid compound (A) and the above organoalkoxy decane (B), thereby forming a dense Three-dimensional cross-linked film. Therefore, the film can further fix the component which functions as a corrosion inhibitor of the metal material, and further improve the corrosion resistance.

One of the preferred embodiments of the organoalkoxydecane is a compound represented by the following formula (I).

In the formula (I), X represents any one of a group selected from the group consisting of an epoxy group, an amine group, a thiol group, a propenyloxy group, a guanidino group, an isocyanate group, and a vinyl group. Among them, an epoxy group and an amine group are preferred. Further, when n is 2 or more, X may be the same or different.

In the formula (I), L represents a divalent linking group or only a bonding.

Examples of the linking group represented by L include an alkylene group (preferably having 1 to 20 carbon atoms), -O-, -S-, an extended aryl group, -CO-, -NH-, -SO ₂ -, -COO-, -CONH-, or a combination of these. Among them, an alkyl group is preferred. When only the bond is indicated, X representing the formula (I) is directly bonded to Si (germanium atom).

Further, when X is 2 or more, L may be the same or different.

In the formula (I), R is independently an alkyl group (preferably having 1 to 4 carbon atoms) or a hydrogen atom.

In the formula (I), n represents an integer of 1 to 3. Of these, it is preferably 1.

Further, the organoalkoxydecane (B) may also be a hydrolyzate in which the alkoxy group is partially hydrolyzed.

The content of the organoalkoxydecane (B) in the surface treatment agent for a metal material is not particularly limited, and the obtained film is excellent in corrosion resistance, top coatability, heat resistance, weldability, continuous processability, grounding property, The total solid content in the treatment agent is preferably from 0.1 to 70% by mass, and more preferably from 1 to 50% by mass, from the viewpoint of further excellent adhesion to the surface of the metal material.

<Metal Compound (C)>

The surface treatment agent for a metal material of the present invention contains a group selected from the group consisting of Zr, Ti, Co, Fe, V, Ce, Mo, Mn, Mg, Al, Ni, Ca, W, Nb, Cr, and Zn. A metal compound (C) of at least one metal element. By using the metal compound (C) in combination with a phosphoric acid compound and/or a fluorine compound described later, a poorly soluble salt is formed in the film. It is presumed that the poorly soluble salt promotes the progress of the crosslinking reaction between the above-described citric acid compound (A) and the above organoalkoxydecane (B), thereby forming a film having a dense mesh structure, whereby the metal can be exhibited. The metal compound (C) which functions as a corrosion inhibitor of the material is fixed in the film.

The metal compound (C) is not particularly limited as long as it contains the above-mentioned metal element, and examples thereof include a nitrate, a sulfate, an acetate, a phosphate, an ammonium salt, a fluoride, and the like of the above metal.

Specific examples of the metal compound (C) include zirconium nitrate, zirconyl nitrate, zirconyl acetate, zirconyl sulfate, zirconium ammonium carbonate, potassium zirconium carbonate, sodium zirconium carbonate, and oxidation. Zirconium sol and the like. Further, zirconium acid and a salt thereof obtained by ion-exchange or alkali-neutralizing an aqueous solution of a water-soluble zirconium salt can also be mentioned.

Examples of the metal compound containing Ti include titanyl sulfate, titanium oxynitride, titanium nitrate, titanium oxychloride, titanium chloride, titanium oxide sol, titanium oxide, potassium oxalate titanate, titanium lactate, and titanium tetraisopropoxide. , acetonitrile titanium, diisopropyl titanium diacetone acetone, and the like. Further, a metatitanic acid obtained by thermally hydrolyzing an aqueous solution of titanyl sulfate or an orthotitanic acid obtained by neutralization with a base and salts thereof may be mentioned.

Examples of the metal compound containing Co include cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt phosphate, cobalt chloride, cobalt oxide, and cobalt hydroxide.

Examples of the metal compound containing Fe include iron sulfate, iron nitrate, iron chloride, iron phosphate, iron oxide, iron hydroxide, iron powder, and the like.

Examples of the metal compound containing V include vanadium pentoxide, ammonium metavanadate, sodium metavanadate, vanadium trioxide, vanadium trioxide, vanadium oxychloride, vanadyl sulfate, vanadyl oxyacetate, and vanadium. Ethylene acetonide vanadium, vanadium trichloride, phosphorus vanadium molybdate, vanadium sulfate, and the like.

Examples of the metal compound containing Ce include cerium nitrate, cerium acetate, cerium chloride, cerium sol, and the like.

Examples of the metal compound containing Mo include ammonium molybdate, sodium molybdate, potassium molybdate, and ammonium molybdate phosphate.

Examples of the metal compound containing Mn include potassium permanganate, ammonium permanganate, sodium permanganate, permanganate, manganese sulfate, manganese nitrate, manganese oxide, manganese carbonate, manganese chloride, manganese phosphate, and the like. .

Examples of the metal compound containing Mg include magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium phosphate, magnesium chloride, magnesium oxide, and magnesium hydroxide.

Examples of the metal compound containing Al include alumina, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum phosphate, and aluminum chloride.

Examples of the metal compound containing Ni include nickel oxide, nickel hydroxide, nickel sulfate, nickel nitrate, nickel phosphate, and nickel chloride.

Examples of the metal compound containing Ca include calcium oxide, calcium hydroxide, calcium sulfate, calcium nitrate, calcium phosphate, and calcium chloride.

Examples of the metal compound containing W include ammonium metatungstate, sodium metatungstate, potassium metatungstate, paratungstic acid, ammonium paratungstate, and sodium paratungstate.

Examples of the metal compound containing Nb include cerium oxalate, cerium oxide, cerium sol, and the like.

Examples of the metal compound containing Cr include trivalent chromium, chromium sulfate, chromium nitrate, chromium chloride, chromium hydroxide, chromium oxide, and chromium phosphate.

Examples of the metal compound containing Zn include zinc oxide, zinc hydroxide, zinc sulfate, zinc nitrate, zinc chloride, zinc phosphate, and acetylated zinc. In addition, since zinc is an amphoteric metal, a base is used. The resulting sodium zincate, potassium zincate, and the like.

Among these, from the viewpoint of the high effect of improving the corrosion resistance, a metal compound containing Zr, V, Al, or Zn and at least one selected from the group consisting of these salts are preferable.

The content of the metal compound (C) in the surface treatment agent for a metal material is not particularly limited, and from the viewpoint of further improving the corrosion resistance and the grounding property of the obtained film, the total solid content in the treatment agent is preferably 0.05 to ～. 50% by mass, more preferably 0.1 to 30% by mass.

<phosphoric acid compound and/or fluorine compound>

The surface treatment agent for a metal material of the present invention contains at least one compound (D) selected from the group consisting of a phosphoric acid compound and a fluorine compound. As described above, the crosslinking reaction between the above-mentioned citric acid compound (A) and the above organoalkoxydecane (B) is promoted by using a phosphoric acid compound and/or a fluorine compound in combination with the metal compound (C). Further, it is presumed that the phosphoric acid compound and/or the fluorine compound etch the metal of the substrate to form a film bonded to the surface of the substrate, so that the corrosion resistance of the film and the adhesion to the surface of the metal material can be further improved.

Examples of the phosphoric acid compound include an ammonium salt of a phosphoric acid and a metal salt (for example, an alkali metal, V, Co, W, Ti, Zr, Al, or Zn); a condensed phosphoric acid such as pyrophosphoric acid; phytic acid; An organic phosphate compound having a phosphonic acid group or a phosphino group. For example, phosphoric acid, metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, tetraphosphoric acid, and the like, the ammonium salt, the aluminum salt, the magnesium salt, the nitrogen trimethylene phosphonic acid, the nitrogen tris-propylphosphonic acid, Nitrogen diethylmethylene phosphonic acid, nitrogen propyl bismethylene phosphonic acid methane, 1-hydroxymethane-1,1-diphosphonic acid, and the like.

The phosphoric acid compounds may be used alone or in combination of two or more.

Examples of the fluorine compound include hydrofluoric acid, an ammonium salt thereof, and an alkali metal salt thereof; tin fluoride, manganese fluoride, ferrous fluoride, iron fluoride, aluminum fluoride, zinc fluoride, vanadium fluoride, and the like. Metal fluoride; acid fluoride such as fluorine oxide, fluorinated acetonitrile, fluorinated benzoate or the like.

Further, at least one element having a group selected from the group consisting of Ti, Zr, Hf, Si, Al, and B can be preferably used. Specific examples thereof include (TiF ₆ ) ^2- , (ZrF ₆ ) ^2- , (HfF ₆ ) ^2- , (SiF ₆ ) ^2- , (AlF ₆ ) ^3- , (BF ₄ OH) ^- and the like. The anion has a complex of 1 to 3 hydrogen atoms, an ammonium salt of the anion, a metal salt of the anion, and the like. More specifically, titanium hydrofluoride, zirconium hydrofluoride, cesium hydrofluoride or the like can be given.

The fluorine compounds may be used singly or in combination of two or more.

The content of the compound (D) in the surface treatment agent for a metal material is not particularly limited, and from the viewpoint of further improving the corrosion resistance of the obtained film, the total solid content in the treatment agent is preferably from 0.1 to 40% by mass. More preferably, it is 0.1 to 30% by mass.

<water>

The surface treatment agent for a metal material of the present invention contains water (E).

The content of the water in the surface treatment agent for a metal material is not particularly limited, and from the viewpoint of easier use of the treatment agent, the total amount of the treatment agent is preferably from 30 to 99% by mass, more preferably from 40 to 95% by mass. %.

<Alcohol (F)>

The surface treatment agent for a metal material of the present invention contains the alcohol (F) produced by hydrolysis of the above organoalkoxydecane (B). The organoalkoxydecane (B) having an alkoxy group produces an alcohol by a hydrolysis reaction.

The type of the alcohol is determined depending on the type of the alkoxy group of the organoalkoxydecane to be used, and examples thereof include methanol, ethanol, and propanol.

The molar concentration (mol/L) (C _F1 ) of the alcohol (F) contained in the surface treatment agent for metal materials of the present invention and the treatment obtained by hydrolysis of all alkoxy groups contained in the organoalkoxy decane The relationship between the molar concentration (mol/L) (C _F2 ) of the alcohol in the agent is adjusted to satisfy (C _F1 /C _F2 ) = 0.05 to 0.9, preferably 0.1 to 0.8.

If the above molar concentration ratio (C _F1 /C _F2 ) is less than 0.05, the reactive functional group necessary for the formation of a siloxane coupling of the decanoic acid compound (A) and the organoalkoxy decane (B) will be organic. Since the alkoxydecane (B) is lost, the corrosion resistance and top coatability of the film, and the adhesion between the formed film and the surface of the metal material are lowered. Further, when the molar concentration ratio (C _F1 /C _F2 ) exceeds 0.9, the effect of the reactive functional group is high, and a siloxane coupling is formed between the organoalkoxy decanes (B), making it impossible to form The component which acts as a corrosion inhibitor of a metal material is fixed in the film.

The method of adjusting the molar concentration (mol/L) (C _F1 ) of the alcohol derived from the alkoxy group of the organoalkoxydecane (B) is not particularly limited, and examples thereof include the following methods: A method in which a sterol-condensed catalyst and a solution of water are mixed in a decane, a method of controlling the amount of the alcohol of the by-product, and a concentration thereof, and a method of removing the alcohol and water of the by-product to adjust the concentration thereof.

Further, the method for measuring the concentration of the alcohol is not particularly limited, and examples thereof include a gas chromatography layer analysis method, an ion gas chromatography layer analysis method, and a nuclear magnetic resonance resonance spectroscopy method.

Further, in the surface treatment agent for a metal material of the present invention, the mass ratio (C/F) of the metal compound (C) to the alcohol (F) is preferably from 0.01 to 50, more preferably from 0.1 to 40. When it is in the above range, the component which exhibits the function of the corrosion inhibitor of the metal material can be fixed to the film, so that the obtained film can be more excellent in corrosion resistance, top coatability, and adhesion to the surface of the metal material. Preferably.

Further, in the surface treatment agent for a metal material of the present invention, the mass ratio (D/F) of the compound (D) to the alcohol (F) is preferably from 0.01 to 25, more preferably from 0.1 to 20, most preferably from 0.1 to ～. 15. When it is in the above range, the component which exhibits the function of the corrosion inhibitor of the metal material can be fixed to the film, so that the obtained film can be more excellent in corrosion resistance, top coatability, and adhesion to the surface of the metal material. Preferably.

The mass ratio (A/B) of the phthalic acid compound (A) to the organoalkoxydecane (B) in the surface treatment agent for a metal material of the present invention is preferably from 0.01 to 3.0, more preferably from 0.05 to 2.5. If it is less than 0.01, the continuous workability may be lowered. When it exceeds 3.0, the adhesion between the formed film and the surface of the metal material may be lowered.

The mass ratio of the total mass (A+B) of the citric acid compound (A) and the organoalkoxy decane (B) to the metal compound (C) in the surface treatment agent for a metal material of the present invention (C/(A+B) )) is preferably from 0.01 to 2.0, more preferably from 0.05 to 1.5. If it is less than 0.01, the corrosion resistance of the film may be lowered. When it exceeds 2.0, the corrosion resistance of the film may be lowered, and the adhesion between the film and the surface of the metal material may be lowered.

The mass ratio of the total mass (A+B) to the compound (D) of the citric acid compound (A) and the organoalkoxy decane (B) in the surface treatment agent for metal materials of the present invention (D/(A+B) It is preferably from 0.01 to 1.5, more preferably from 0.05 to 1.0. If it is less than 0.01, the corrosion resistance of the film may be lowered. If it exceeds 1.5, the corrosion resistance and the grounding property of the film may be lowered, and the adhesion between the film and the surface of the metal material may be lowered, and it is difficult to cause corrosion of the metal material. The components of the inhibitor are immobilized in the membrane.

<Other additives>

The surface treatment agent for a metal material of the present invention may contain various additives as needed. The following describes the additives contained therein.

<Water-soluble polymer and/or aqueous emulsion resin>

The surface treatment agent for a metal material of the present invention may contain at least one compound (G) of a group consisting of a water-soluble polymer and an aqueous emulsion resin. By the addition of the compound (G), the anti-fingerprint property and lubricity of the film can be improved.

The type of the water-soluble polymer and/or the water-based emulsion resin is not particularly limited, and examples thereof include a water-soluble polymer such as polyacrylic acid, polymethacrylic acid, polypropylene decylamine, and polyvinyl alcohol, and are dispersed in water. Acrylic resin, urethane resin, epoxy resin, polyester resin, polyamide resin, polyolefin resin, ethylene-acrylic resin, polybutyraldehyde resin, polyacetal resin, fluororesin, and the like.

The content of the compound (G) in the surface treatment agent for a metal material of the present invention is not particularly limited. Wherein the mass ratio (G/(A+B)) of the total mass (A+B) to the compound (G) of the citric acid compound (A) and the organoalkoxy decane (B) in the treating agent is preferably 0.01 to 0.3, more preferably 0.05 to 0.25. If it is less than 0.01, the fingerprint resistance and lubricity of the film may not be improved, and if it exceeds 0.3, the corrosion resistance and heat resistance of the film may be lowered.

The surface treatment agent for a metal material of the present invention may further contain a decyl alcohol condensation catalyst. The sterol condensation catalyst is not particularly limited, and examples thereof include formic acid, acetic acid, butyric acid, oxalic acid, succinic acid, lactic acid, L-ascorbic acid, tartaric acid, citric acid, DL-malic acid, malonic acid, and maleic acid. Phthalic acid, nitrogen trimethylene phosphonic acid, nitrogen tris-propylphosphonic acid, nitrogen diethyl methylene phosphonic acid, nitrogen propyl bis methylene phosphonic acid methane, methane-1-hydroxy-1 , 1-diphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, propane-1-hydroxy-1,1-diphosphonic acid, sulfonic acid, benzenesulfonic acid, ketimines, aldehyde Imine, enamine, oxazolidine compound, amine alkyl alkoxy decane, and the like.

The surface treatment agent for a metal material of the present invention may further contain an anti-rust additive containing N. Examples of such an ethylene diamine, triethylamine, urea, hydrazine, and the like are mentioned.

The surface treatment agent for a metal material of the present invention may optionally contain an additive (lubricant) for improving lubricity. By improving the lubricity of the film, the film is prevented from being scratched, and the damage of the film during processing is effectively reduced.

Examples of the additive include polyethylene wax, oxidized polyethylene wax, oxidized polypropylene wax, carnauba wax, paraffin, montan wax, rice wax, Teflon (registered trademark) wax, carbon disulfide, and graphite. Such as solid lubricants. One or two or more kinds of these solid lubricants can be used.

The surface treatment agent for a metal material of the present invention may optionally contain an alcohol, a ketone, a water-soluble solvent of a serotonin system, a surfactant, an antifoaming agent, a leveling agent, an antibacterial antifungal agent, a coloring agent, and the like. Thereby, the drying property of the treatment agent, the coating appearance, the workability, the storage property, and the pattern property can be improved. However, these must be added in such a manner as not to impair the quality of the present invention, and are at most several mass% in the treatment liquid.

The pH of the surface treatment agent for a metal material of the present invention may be acidic or basic as long as the treatment liquid can be stably produced. However, when the pH is less than 0.5, the reactivity with the metal material may increase to lower the appearance, and if it exceeds 14, the stability of the metal compound may decrease, and the stability of the treatment agent itself may decrease. Not good.

The surface treatment agent for a metal material of the present invention may optionally contain a solvent other than the above water (for example, an alcohol or the like).

The method for preparing the surface treatment agent for a metal material of the present invention is not particularly limited. For example, the citric acid compound (A), the organoalkoxy decane (B), the metal compound (C), the phosphoric acid compound, and/or the fluorine compound (D), and water (E) can be thoroughly mixed using a mixer such as a mixing homogenizer. To manufacture.

<Surface treatment method>

The surface treatment method for the surface treatment agent for a metal material of the present invention is not particularly limited, but it is preferably a surface treatment method in which the surface treatment agent for the metal material is applied onto the surface of the metal material and dried by heating. The amount of the film formed on the surface of the metal material is from 2 to 1000 mg/m ² in terms of the amount of Si applied.

Hereinafter, the surface treatment method will be described.

Prior to coating, pre-treatment of the metal material may also be performed as needed to achieve the purpose of removing oil or dirt on the surface of the metal material. Metal materials are often coated with anti-rust oil based on anti-rust purposes. In addition, even if the anti-rust oil is not coated, there will be oil or dirt adhering to the operation. The surface of the metal material is washed by pre-treatment, and the surface of the metal material can be uniformly wetted by the surface treatment agent for the metal material of the present invention. Further, in the case where the surface of the material is uniformly wetted by the surface treatment agent for a metal material of the present invention without oil or dirt, etc., there is no particular need for a pretreatment step.

Further, the method of the pretreatment is not particularly limited, and examples thereof include a method of washing with hot water, washing with a solvent, and washing with an alkali degreasing.

Examples of the metal material to be used include a hot-dip galvanized steel sheet (GI), an alloyed hot-dip galvanized steel sheet (GA) after alloying, and a hot-dip Zn-5% Al alloy steel sheet (GF) and hot-dip galvanizing. - 55% aluminum alloy steel sheet (GL), electrogalvanized steel sheet (EG), electrogalvanized nickel-nickel alloy steel sheet (Zn-Ni), aluminum plated, aluminum plate, and the like. In addition, it can also be applied to iron plates that are not plated.

As a method of coating the metal material with a surface treatment agent for a metal material, the most suitable method can be selected depending on the shape of the metal material to be treated, and the like, and a roll coating method, a dipping method, a spray coating method, or the like can be mentioned.

More specifically, for example, in the case where the object is in the form of a sheet, the coating amount can be adjusted by a roll coating method or by spraying a treatment liquid onto a metal material and applying a high pressure gas by a roll. When the object is a molded article, it may be immersed in the treatment liquid and then picked up, and the excess treatment liquid may be blown away by compressed air as the case may be, to adjust the coating amount.

The heating temperature of the coating film formed on the surface of the dried metal material is preferably 40 to 250 ° C, more preferably 60 to 200 ° C, most preferably 60 to 180 ° C. When it is less than 40 ° C, the water as a main solvent of the treating agent of the present invention remains, and the metal compound cannot be fixed, and the corrosion resistance of the film is lowered. When it exceeds 250 ° C, the film may be easily cracked and the corrosion resistance may be lowered. The heating and drying method is not particularly limited, and the treatment agent can be dried by heating with hot air or a conductive heater, infrared rays, near infrared rays or the like.

Further, the heating time can be selected in accordance with the kind of the compound in the surface treatment agent for the metal material to be used. Among them, from the viewpoint of productivity and the like, it is preferably from 0.1 to 60 seconds, more preferably from 1 to 30 seconds.

The amount of the film formed on the surface of the metal material is adjusted to be 2 to 1000 mg/m ² , preferably 10 to 800 mg/m ² , more preferably 2 to 500 mg/m ² in terms of the amount of the coating. When it is less than 2 mg/m ² , the effect of the present invention may not be sufficiently obtained. When it exceeds 1000 mg/m ² , the effect is saturated, and in addition to being economically wasted, the corrosion resistance may be lowered depending on the case.

On the film formed by the above surface treatment method, an organic polymer film having a film thickness of 0.1 to 3.0 μm after drying can be formed to impart higher corrosion resistance, fingerprint resistance, and lubricity. As the organic polymer film, a conventional resin emulsion such as an acrylic, urethane or epoxy resin, or a cerium oxide, a rust inhibitor, a lubricant, an ultraviolet absorber, a pigment or the like may be added thereto.

By surface treatment of a metal material with a surface treatment agent using the above metal material, a surface treatment film having corrosion resistance, top coatability, heat resistance, weldability, continuous processability, grounding property, and anti-fingerprint property can be formed. In particular, the formed film is excellent in adhesion to the surface of the metal material, and a component that functions as a corrosion inhibitor of the metal material can be fixed to the film.

The surface-treated metal material obtained by using the surface treatment agent for a metal material of the present invention can be suitably used for various purposes. For example, materials used in various fields such as construction, electric, and automobiles can be cited.

Example

The effects of the present invention will be described by way of examples and comparative examples. However, this embodiment is merely illustrative of the invention and is not intended to limit the invention.

1. Method for preparing test plate

(1) Test materials

The following commercially available materials were used as test materials.

(i) Electrogalvanized steel sheet (EG): plate thickness 0.8 mm, plating amount = 20/20 (g/m ² )

(ii) hot-dip galvanized steel sheet (GI): sheet thickness 0.8mm, plating amount = 60/60 (g / m 2)

(iii) alloyed hot-dip galvanized steel sheet (GA): plate thickness 0.8 mm, plating amount = 40/40 (g/m ² )

Further, the amount of plating indicates the amount of plating on the main surface of the steel sheet. For example, in the case of an electrogalvanized steel sheet, it is 20/20 (g/m ² ), that is, it means that the both sides of the steel sheet have a plating layer of 20 g/m ² , respectively.

(2) pre-treatment (washing)

The test plate was first prepared by treating the surface of the above test material with Palklin N364S manufactured by Nihon Parkerizing Co., Ltd., and removing oil and dirt on the surface. Next, it was washed with tap water, and it was confirmed that the surface of the metal material was 100% wetted by water, and then rinsed with pure water, and the moisture was removed in an oven at 100 ° C ambient atmosphere, and this was used as a test plate.

(3) Adjustment of the treatment liquid of the present invention

The components were mixed in water in the composition (solid mass ratio) shown in Table 1 to prepare a treatment liquid.

In addition, the compounding quantity of the components (A), (B), (C), (D), and (G) in Table 1 shows the quantity (g) blended in 1 kg of surface-treatment liquid for metal materials. Further, the content of the alcohol component (F) is measured by a gas chromatograph, and C _{F2 is} calculated from the content of the organoalkoxydecane, and the following molar concentration ratio is expressed as (C _F1 ) / (C _F2 ) .

Hereinafter, the compounds used in Table 1 will be described.

<矽 compound (A)>

A1: SNOWTEX C (manufactured by Nissan Chemical Industries, Ltd.)

A2: SNOWTEX O (manufactured by Nissan Chemical Industry Co., Ltd.)

<Organic alkoxydecane (B)>

B1: γ-glycidoxytriethoxydecane

B2: Aminopropyltriethoxydecane

B3: ethylene triethoxy decane

B4: tetraethoxy decane

<Metal Compound (C)>

C1: ammonium zirconium carbonate

C2: tetraethyl hydrazine acetone vanadium

C3: Magnesium nitrate

C4: Aluminum nitrate

C5: zinc oxide

<compound (D)>

D1: phosphoric acid

D2: 1-hydroxymethane-1,1-diphosphonic acid

D3: titanium hydrofluoride

D4: zirconium hydrofluoride

<Alcohol concentration (mole concentration ratio) (C _F1 ) / (C _F2 )>

<compound (G)>

G1: Acrylic resin (made by Showa Polymer Co., Ltd., Polysol AM-2386)

(4) Processing method

The surface treatment liquid for the above-mentioned metal materials was applied to each test plate by the following coating method, and then washed without being washed, and directly placed in an oven, and dried at a drying temperature shown in Table 2 to form Table 2 The film showing the amount of film.

The drying temperature is adjusted in accordance with the ambient temperature in the oven and the time it is placed in the oven. Further, the drying temperature means the temperature at which the surface of the test plate reaches. Specific methods of the bar coating method and the spray & winch coating method are as follows.

Bar coating method: A treatment agent was dropped on a test plate, and coated with a #3 to 5 coating bar. The amount of the coating film is adjusted to a predetermined amount depending on the thickness of the coating bar to be used and the concentration of the treatment liquid.

Roll coating method: The test plate was immersed in the treatment liquid at room temperature for about 1 second, and after taking out, the excess liquid was removed by a roller to adjust the coating amount. The amount of water removed by the roller and the concentration of the treatment liquid are adjusted to a predetermined amount of film.

(5) Evaluation test method

(5-1) Evaluation of corrosion resistance

The surface-treated test plate was cut into a size of 70 × 150 mm, and the inner side and the end portion were attached with a vinyl tape, and then the following test was performed. The evaluation was performed by visually measuring the area ratio of rust generation.

Salt spray test (according to SST: JIS-Z-2371): The area ratio of white rust after 120 hours of SST was visually measured, and evaluated by the following criteria.

Cyclic test (CCT (JASO): M609-91 (corrosion test method for automotive materials)): The area ratio of white rust after the CCT 30 cycle was visually measured, and evaluated by the following criteria.

Benchmark:

◎: The area ratio of rust generation is less than 10%

○: The area ratio of rust generation is 10% or more and less than 20%.

△: The area ratio of rust generation is 20% or more and less than 40%.

╳: The area ratio of rust generation is 40% or more

╳╳: The whole surface is rusty

(5-2) Evaluation of adhesion to metal materials

Method A: a stainless steel round rod having a diameter of 40 mm and having a surface polished into a mirror shape was subjected to a surface of the surface-treated test plate with an external force of 50 kg for 10 times, followed by peeling off the tape, followed by an aqueous solution of copper sulfate (3% aqueous solution). The plating was performed by immersion for 5 seconds at room temperature, and the peeling state of the film was evaluated.

Method B: The surface-treated test plate was extruded by 7 mm using an Aristotle extruder, and the entire processed portion was peeled off with Sellotape (registered trademark), and then immersed in an aqueous solution of copper sulfate (3% aqueous solution at room temperature for 5 seconds). The substitution plating was performed, and the peeling state of the film was evaluated.

Benchmark:

◎: no peeling

○: Only a little punctiform peeling

△: a little peeling

╳: Obvious stripping

(5-3) Evaluation of the elution of metal compounds

The surface-treated test plate was immersed in boiling pure water for 2 hours, and the residual amount of the metal compound was measured by a fluorescent X-ray analyzer. The metal fixation rate was calculated from the adhesion amount of the metal compound measured before the test.

Fixation rate (%) = residual amount (mg/m ² ) / pre-test adhesion amount (mg/m ² ) × 100

Benchmark:

◎: 95% or more to 100%

○: 90% or more and less than 95%

△: 60% or more and less than 90%

╳: 20% or more and less than 60%

╳╳: less than 20%

(5-4) Evaluation of top coatability

A commercially available melamine alcohol coating was applied to a surface-treated test plate to have a coating film thickness of 20 μm after firing at 160 °C. After that, it was immersed in boiling water for 2 hours, and then 100 grids of 1 mm square were cut by an NT cutter, and the part was extruded by 6 mm using an Alice Indentation Tester, and the tape was peeled off, and the residual state of the coating film was removed. The following evaluations were carried out.

Benchmark:

◎: not peeled off - peeling less than 5%

○: peeling 5% or more and less than 10%

△: peeling 10% or more and less than 20%

╳: peeling 20% or more and less than 60%

╳╳: Stripped more than 60%

Corrosion resistance test: A slit having an X-shaped depth up to the material was cut out with an NT cutter on a test plate, and then subjected to the above-mentioned CCT (cycle test) for 80 cycles, and then the state of generation of rust was evaluated by the following criteria. .

Benchmark:

◎: less than 1mm from the incision

○: 1mm or more from the incision, less than 2mm

△: 2mm or more from the incision, less than 5mm

╳: 5mm or more from the incision

╳╳: peeling of the coating film

With respect to the surface-treated metal materials obtained by using the surface treatment agent for metal materials described in Examples 1 to 51 and Comparative Examples 52 to 67, the evaluation results of the above (5-1) to (5-4) are shown. In Table 3.

In addition, from a practical point of view, there must be no "╳" and "╳╳" in the above evaluation items.

As shown in Table 3, it was confirmed that the treatment agent of the present invention containing a predetermined compound and having an alcohol molar concentration ratio (C _F1 )/(C _F2 ) was excellent in top coatability and a film formed thereon. It is excellent in adhesion to the surface of a metal material, and can suppress precipitation of a component which exhibits a function as a corrosion inhibitor of a metal material.

In the comparison of Examples 23 to 26, it is understood that the organoalkoxydecane (B) is more excellent in properties when an organoalkoxydecane having an epoxy group or an amine group is used. Further, from the comparison of Examples 16 and 17, it is understood that when two kinds of organo alkoxydecane are used, the respective characteristics can be further improved.

On the other hand, in the comparative examples, the results which can comprehensively satisfy the characteristics were not obtained.

Claims (9)

A surface treatment agent for a metal material, comprising: a phthalic acid compound (A); an organoalkoxy decane (B); and a metal compound (C) containing a component selected from the group consisting of Zr, Ti, Co, Fe, V, Ce, Mo At least one metal element of the group consisting of Mn, Mg, Al, Ni, Ca, W, Nb, Cr, and Zn; and the compound (D) is selected from the group consisting of a phosphoric acid compound and a fluorine compound. At least one; water (E); alcohol (F), which is produced by hydrolysis of the organoalkoxydecane (B); molar concentration (mol/L) of the alcohol (F) in the treating agent (C _F1 ) ratio of molar concentration (mol/L) (C _F2 ) of the alcohol formed in the treatment agent when all alkoxy groups contained in the organoalkoxydecane (B) are hydrolyzed (C _{F1 )} /C _F2 ), adjusted in the range of 0.05 to 0.9. A surface treatment agent for a metal material according to the first aspect of the invention, wherein a mass ratio (C/F) of the alcohol (F) to the metal compound (C) is 0.01 to 50. A surface treatment agent for a metal material according to claim 1 or 2, wherein a mass ratio (D/F) of the alcohol (F) to the compound (D) is 0.01 to 25. The surface treatment agent for metal materials according to claim 1 or 2, wherein the mass ratio (A/B) of the phthalic acid compound (A) to the organo alkoxy decane (B) is 0.01 to 3.0; The mass ratio (C/(A+B)) of the total mass (A+B) of the citric acid compound (A) and the organoalkoxydecane (B) to the metal compound (C) is 0.01 to 2.0; The mass ratio (D/(A+B)) of the total mass (A+B) of the citric acid compound (A) and the organoalkoxydecane (B) to the compound (D) is from 0.01 to 1.5. A surface treatment agent for a metal material according to claim 1 or 2, wherein the organoalkoxydecane (B) has an amine group and/or an epoxy group. The surface treatment agent for metal materials according to claim 1 or 2, further comprising a compound (G); the compound (G) being at least selected from the group consisting of a water-soluble polymer and an aqueous emulsion resin. 1 species. The surface treatment agent for metal materials according to claim 6, wherein the mass ratio of the total mass (A+B) of the phthalic acid compound (A) and the organoalkoxy decane (B) to the compound (G) (G/(A+B)) is from 0.01 to 0.3. A surface treatment method for a metal material, which is coated with a surface treatment agent for a metal material according to any one of claims 1 to 7 on a surface of a metal material, and dried by heating to form a film amount on the surface of the metal material. The film is 2 to 1000 mg/m ² in terms of Si adhesion amount. A surface-treated metal material having a film on its surface, which is obtained by a surface treatment method of a metal material according to claim 8 of the patent application.