JP2002241956A - Metallic surface treatment agent, metallic surface treatment method and surface treated metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic surface treatment agent which gives excellent corrosion resistance and electric conductivity to the film formed therefrom, and excellent coating adhesion in the formation of a top coating film on a film, a metallic surface treatment method, and a surface treated metallic material. SOLUTION: The water based coating agent for a metallic material is a water based composition bleded with a water based dispersion resin of 5 to 30 mass% by a solid content, silica fine particles of 1 to 10 mass%, 0.02 to 5 mass% of at least one compound selected from organic inhibitor groups consisting of an urea compound, a guanidine compound, a phosphonate compound, a thiophosphate compound, a phosphine oxide compound, and a phosphine sulfide compound, and phosphoric ions of 0.01 to 0.5 mass%. The water based dispersion resin is a water dispersed body obtained by reacting a water-dispersed ionomer resin obtained by neutralizing >=30% of the carboxylic group in an ethylene-unsaturated carboxylic acid copolymer containing unsaturated carbonic acid in 10 to 30 mass% with an epoxy group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal surface treating agent,
The present invention relates to a metal surface treatment method and a surface treated metal material, and more particularly to a metal surface treatment agent containing an aqueous dispersion of an ionomer resin.

[0002]

2. Description of the Related Art Conventionally, galvanized steel sheets whose surfaces are subjected to chromate treatment in order to ensure corrosion resistance have been widely used for home electric appliances, office equipment, building materials, automobiles and the like. However, since chromate treatment uses hexavalent chromium, which is harmful to health, there is a concern about adverse effects on humans and the environment in the chromate treatment step, treatment of chromium wastewater, and use of the chromate treated product. For these reasons, many rust-preventive treatments for zinc-based plated steel sheets without using chromate treatment have been proposed, and among them, the treatment of an organic film containing an inhibitor other than chromium has become important. As one of methods for forming an organic film, there is known a method using an aqueous dispersion of an ionomer resin obtained by neutralizing a copolymer of ethylene and an unsaturated carboxylic acid with metal ions. This ionomer resin has good adhesion to various base materials, especially metals, and the formed film is tough and resistant to scratches and has excellent solvent resistance to solvents such as ethanol and methyl ethyl ketone. Material. Further, there has been proposed an aqueous dispersion composition formed by mixing an ionomer resin with a polyvalent epoxy compound at a temperature of 50 ° C. or lower (JP-A-4-314748). Furthermore,
A rust preventive agent for metal materials containing an ionomer resin neutralized with a divalent metal such as magnesium or zinc has been proposed (JP-A-11-71536).

However, a film formed of the above-mentioned ionomer resin or a composition based on the ionomer resin has insufficient conductivity when the film thickness is large, and when a top coat is applied. However, good coating adhesion cannot always be obtained.

[0003] The present invention has been made in view of the above problems, and particularly when used as a surface treatment agent on a zinc-based plated steel sheet, corrosion resistance can be ensured, and the film has excellent conductivity.
Another object of the present invention is to provide a metal surface treatment agent, a metal surface treatment method, and a surface-treated metal material having excellent coating adhesion when a top coat is applied on a film.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies on the above problems and as a result have reached the following present invention. 1. From an organic inhibitor group consisting of an aqueous dispersion resin in a solid content concentration of 5 to 30% by mass, silica fine particles of 1 to 10% by mass, a urea compound, a guanidine compound, a phosphonate compound, a thiophosphate compound, a phosphine oxide compound and a phosphine sulfide compound. An aqueous composition containing 0.02 to 5% by mass of at least one selected compound and 0.01 to 0.5% by mass of a phosphate ion, wherein the aqueous dispersion resin contains 1% of unsaturated carboxylic acid.
Water obtained by neutralizing 30% or more of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer containing 0 to 30% by mass with potassium ions, and reacting the water-dispersed ionomer resin with the epoxy compound. A metal surface treatment agent, which is a dispersion. 2. The above metal surface treatment agent comprising a composite aqueous dispersion resin obtained by radical polymerization of an unsaturated monomer in the presence of the aqueous dispersion resin. 3. The above metal surface treatment agent, further comprising at least one aqueous resin selected from an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acrylic resin. 4. In a mixture of the aqueous dispersion resin and an aqueous polyurethane resin, an aqueous polyester resin, and at least one aqueous resin selected from aqueous acrylic resins, a composite aqueous dispersion resin mixture obtained by radical polymerization of an unsaturated monomer is used. A metal surface treatment agent comprising: 5. A metal surface treatment method comprising applying the metal surface treatment agent to the surface of a metal material to form a film. 6. The above metal surface treatment method, further comprising applying a top coat on the film to form a coating film. 7. A surface-treated metal material obtained by the above metal surface treatment method.

[0005]

Embodiments of the present invention will be described below.

The metal surface treating agent of the present invention comprises an aqueous dispersion resin having a solid content of 5 to 30% by mass and a silica fine particle of 1 to 1%.
0% by mass, 0.02 to 5% by mass of at least one compound selected from an organic inhibitor group consisting of a urea compound, a guanidine compound, a phosphonate compound, a thiophosphate compound, a phosphine oxide compound and a phosphine sulfide compound; An aqueous composition containing 0.01 to 0.5% by mass of an ion, wherein the aqueous dispersion resin has 30% of carboxyl groups of an ethylene-unsaturated carboxylic acid copolymer containing 10 to 30% by mass of an unsaturated carboxylic acid. % Is neutralized with potassium ions, and is an aqueous dispersion obtained by reacting an ionomer resin water-dispersed with an epoxy compound.

The unsaturated carboxylic acid of the present invention includes acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, etc., and acrylic acid and methacrylic acid are particularly preferred.

[0008] The ionomer resin of the present invention uses potassium as an ion source. When the ion source is another monovalent ion, for example, sodium, the formed film has insufficient conductivity. Similarly, when the ion source is a divalent ion, for example, zinc or magnesium, the conductivity is not sufficient.

The ionomer resin of the present invention has a degree of neutralization of carboxyl groups by potassium ions of 30% or more. When the degree of neutralization is less than 30%, the conductivity is not sufficient, and when the degree of neutralization is extremely low, the solvent resistance decreases. On the other hand, the upper limit of the degree of neutralization is not particularly limited, but is preferably within 100% from the viewpoint of corrosion resistance.

In the present invention, the aqueous dispersion of the ionomer resin is reacted with an epoxy compound to form an aqueous dispersion resin, and a metal surface treating agent containing the aqueous dispersion resin is obtained.

Here, the epoxy compound refers to a compound having at least one epoxy group in one molecule, and includes glycidyl ethers and glycidyl esters. Examples of glycidyl ethers include phenyl glycidyl ether, resorcin diglycidyl ether, bisphenol A diglycidyl ether, glycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, and pentaerythritol polyglycidyl ether. Examples of glycidyl esters include diglycidyl adipate and diglycidyl phthalate.

The reaction between the ionomer resin and the epoxy compound is carried out at a temperature in the range of 30 ° C. to the boiling point, more preferably 6 ° C.
It is performed at a temperature in the range of 0 to 95 ° C. When the temperature is lower than 30 ° C., the reaction does not proceed sufficiently. The reaction time is 0.5
10 hours.

The above metal surface treating agent is excellent in conductivity of a film when used as a metal surface treating agent, and is excellent in coating adhesion when a top coat is formed on the film.

Further, the metal surface treating agent of the present invention is obtained by further mixing silica fine particles with the above water-dispersible resin.

Here, the silica fine particles are not particularly limited, but for example, have an average particle size of 0.01 to 0.5 μm.
It is preferable to use those having about the same degree, and they can be appropriately selected from colloidal silica and fumed silica. It is preferable that the silica fine particles be blended in an amount of 1 to 10% by mass.

Further, the metal surface treating agent of the present invention is selected from the group consisting of urea compounds, guanidine compounds, phosphonate compounds, thiophosphate compounds, phosphine oxide compounds and phosphine sulfide compounds as organic inhibitors in the above aqueous composition. At least one compound obtained by the above method.

As the urea compound, ethylene urea,
Examples include propylene urea and phenyl urea.

Examples of the guanidine compound include 1-o-tolylbiguanide, diphenylguanidine and the like.

Examples of the phosphonate compound include dimethylphenylphosphonate.

As the thiophosphate compound, di (2
-Ethylhexyl) dithiophosphate and the like.

Examples of the phosphine oxide compound include triethyl phosphine oxide.

As the phosphine sulfide compound,
Tri-n-ethylphosphine sulfide and the like.

Here, the organic inhibitor is 0.02
It is preferable to mix 5% by mass.

The metal surface treating agent of the present invention is obtained by further adding phosphate ions to the above aqueous composition.

Examples of the phosphate ion source include diammonium hydrogen phosphate and the like.

Here, the phosphate ion is 0.01 to 0.5.
It is preferable to mix by mass%.

The metal surface treating agent of the present invention is obtained by blending the above-mentioned silica fine particles, an organic inhibitor, and phosphate ions to obtain a zinc-plated steel sheet surface-treated with a metal surface treating agent to perform a chromate treatment. Can be equivalent to

Further, the metal surface treating agent is excellent in conductivity of a film when used as a surface treating agent, and is excellent in coating adhesion when a top coat is formed on the film.

The metal surface treating agent thus obtained can be further compounded or compounded with the above-mentioned aqueous dispersion resin.

That is, in the presence of the aqueous dispersion resin,
By subjecting the unsaturated monomer to radical polymerization using an initiator, a composite aqueous dispersion resin of an ionomer-based aqueous dispersion resin and an acrylic resin can be obtained.

Further, at least one aqueous resin selected from the group consisting of an aqueous polyurethane resin, an aqueous polyester resin and an aqueous acrylic resin may be added to the aqueous dispersion resin or the composite aqueous dispersion resin.

In a mixture of the above aqueous dispersion resin and at least one aqueous resin selected from the group consisting of an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acrylic resin,
The unsaturated monomer may be subjected to radical polymerization to form a composite aqueous dispersion mixture.

Here, as the unsaturated monomer, alkyl (meth) acrylates, styrene, (meth) acrylic acid, hydroxyalkyl (meth) acrylates, (meth) acrylic acid and the like can be used.

As the polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate, and azo compounds such as azobiscyanovaleric acid and azobisisobutyronitrile can be used.

The aqueous polyurethane resin is, for example,
It can be obtained by reacting a diol with a diisocyanate compound such as hexamethylene diisocyanate, isophorone diisocyanate, or tolylene diisocyanate, further extending the chain with a diamine or the like, and dispersing in water. The aqueous polyester resin can be obtained by, for example, dehydrating and condensing a diol with a polybasic acid, neutralizing with an amine, and solubilizing or dispersing in water.
Aqueous acrylic resin is, for example, a method of radically polymerizing an unsaturated monomer containing an unsaturated carboxylic acid in an organic solvent, neutralizing with an amine or the like, solubilizing or dispersing in water, or in a surfactant aqueous solution. It can be obtained by a method such as emulsion polymerization of an unsaturated monomer.

The other resin to be compounded or compounded is an aqueous dispersion resin 100 before compounding or compounding as a solid content.
It is used in a range of 50 parts by mass or less, more preferably 30 parts by mass or less based on parts by mass.

The metal surface treating agent obtained as described above can improve the corrosion resistance of a film when used as a surface treating agent. If the amount of the composite or compound exceeds 50% by mass, the effect of improving the conductivity of the obtained metal surface treating agent is impaired.

The radical polymerization conditions for obtaining the above composite aqueous dispersion are as follows: a reaction temperature of 40 to 90 ° C., and a reaction time of 0.1 hour.
5 to 10 hours.

In the metal surface treatment method of the present invention, the above-mentioned metal surface treatment agent is applied to the surface of a metal material to form a film. The coating method is not particularly limited, and a normal coating method such as a roll coating method, a spray method, and a dipping method can be used.

The film formed by the above-mentioned metal surface treatment method has excellent conductivity and corrosion resistance, and also has excellent solvent resistance.

In the metal surface treatment method of the present invention, a top coat is applied on the above-mentioned film to form a coating film. The application method is not particularly limited, and a roll coating method,
An ordinary coating method such as a spray method or an immersion method can be used.

The surface-treated metal material obtained by the above-mentioned metal surface treatment method is excellent in coating adhesion of a top coat.

[0043]

The present invention will be further described with reference to Examples and Comparative Examples. The present invention is not limited to the embodiments described below.

(Preparation of Metal Surface Treatment Agent) As shown in Table 1, the following materials were used for the metal surface treatment agent.

[0045]

[Table 1] The metal surface treating agents of Examples and Comparative Examples are Primacol 5980I (manufactured by Dow Chemical, acrylic acid content: 20% by mass) as an ethylene-acrylic acid copolymer, or Nucrel 2060 as an ethylene-methacrylic acid copolymer. (Methacrylic acid content 20% by mass, manufactured by DuPont Mitsui Polychemicals) was used.

As a potassium ion source in the examples, potassium hydroxide was used. Further, as a metal ion source of the comparative example, sodium hydroxide was used as a monovalent sodium ion source, and zinc oxide was used as a divalent zinc ion source.
In some Examples and Comparative Examples, ammonia, which is a volatile neutralizing agent, was used in combination with a metal ion source, or was used instead of a metal ion source.

The epoxy compound of the example was Denacol 3
13 (glycerin polyglycidyl ether manufactured by Nagase Kasei Kogyo), Denacol 321 (trimethylolpropane polyglycidyl ether manufactured by Nagase Kasei Kogyo), or Epikote 828 (bisphenol A diglycidyl ether oil-based shell epoxy) was used.

As the aqueous polyurethane resin, Adekabon Titer HUX-320 (manufactured by Asahi Denka Kogyo) was used.

The unsaturated monomers used in forming the composite aqueous dispersion were those shown in Table 1. Where KP
S is potassium persulfate as a polymerization initiator.

As the silica fine particles to be blended in a plurality of examples, Snowtex N (manufactured by Nissan Chemical Industries, Ltd.) containing colloidal silica having a particle diameter of 10 to 20 nm as a solid content of 20% by mass was used.

In Examples and Comparative Examples of the surface-treated metal material, the compounds shown in Tables 2 to 5 were used as the organic inhibitors to be added to each of the above components. Further, a phosphate ion source was blended.

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

[Table 5] The preparation method of the metal surface treating agent using each of the above-mentioned raw materials was based on the following method.

In a flask equipped with a stirrer, a temperature controller, a dropping funnel, a nitrogen inlet tube, and a condenser, a predetermined amount of the ethylene- (meth) acrylic acid copolymer set in each Example and Comparative Example was added. A predetermined amount of a metal ion source, a predetermined amount of 25% by mass aqueous ammonia for some examples and comparative examples, and a slightly different amount of deionized water for each example and comparative example are charged and stirred. It was kept at a temperature of 95 ° C. for 2 hours. Thereafter, the mixture was cooled with water to obtain an aqueous dispersion having a different neutralization ratio for each of Examples and Comparative Examples. The solids content of this aqueous dispersion was uniformly adjusted to 22% by mass in all of the Examples and Comparative Examples by presetting the amount of deionized water to a slightly different amount for each Example or Comparative Example. I have.

A predetermined amount of the epoxy compound set in each of Examples and Comparative Examples was added to the above aqueous dispersion, and the mixture was maintained at a temperature of 85 ° C. for 2 hours with stirring to complete the reaction. Obtained.

In Example 2, an aqueous polyurethane resin was further added to the aqueous dispersion resin. In Example 3, the unsaturated monomer was polymerized in the presence of the aqueous dispersion resin. In addition, regarding the fourth embodiment,
An unsaturated monomer was polymerized in a mixture of the aqueous dispersion resin and the aqueous polyurethane resin.

The polymerization of the unsaturated monomer was carried out as follows. First, half of the values of the unsaturated monomers shown in Table 1
The mixture was charged into a flask containing an aqueous dispersion resin maintained at a temperature of 0 ° C. while stirring, and 10 minutes later, a 1% aqueous solution of potassium persulfate was added in an amount of 2/3 of the value shown in Table 1 to start the reaction. After a further 10 minutes, the remaining unsaturated monomer is added and then
After another 10 minutes, the remaining 1% aqueous solution of potassium persulfate was added, and then the temperature was kept at 80 ° C. for 2 hours to complete the reaction.

To the obtained aqueous dispersion resin or composite aqueous dispersion resin, predetermined amounts of colloidal silica and deionized water set in each of Examples and Comparative Examples were added to adjust the solid content uniformly to 20% by mass. A metal stock solution was obtained. Table 1 shows specific raw material blending conditions of each of Examples 1 to 6 and Comparative Examples 1 to 5 for the stock solution of the metal surface treatment agent.

The metal surface treating agent stock solution was further added to Tables 2 to 5
A predetermined amount of the organic inhibitor and phosphate ion shown in each of Examples and Comparative Examples was added to obtain again a metal surface treatment agent whose solid content was uniformly adjusted to 20% by mass.

(Preparation of surface-treated metal material) As shown in Tables 2 to 5, EG (electrogalvanized steel sheet) and GI ( Hot-dip galvanized steel sheet). The two types of steel plates were manufactured by Nippon Test Panel 7
Those having dimensions of 0 mm × 150 mm × 0.8 mm were used.

Each of the above steel plates was treated with a 2% solution of Surf Cleaner 53 (Nippon Paint alkaline degreasing agent) at 60 ° C.
After spray degreasing treatment for 120 seconds, washing and drying, the metal surface treating agent of each Example or Comparative Example was applied using a bar coater # 3 so that the film thickness after drying was 1 μm, and reached the steel plate. A film was formed by baking and drying until the temperature reached 150 ° C., and a test plate for evaluating conductivity, corrosion resistance, and solvent resistance described below was obtained.

Further, Super Luck 100 (Nippon Paint Melamine Alkyd Paint) was further applied to the above test material using a bar coater # 32 as a top coat paint so that the film thickness after drying became 20 μm. At 20
The coating film was formed by baking and drying for 5 minutes to obtain a test plate for evaluating the overcoat adhesion described later.

The conductivity, corrosion resistance and solvent resistance of the coatings of Examples 1 to 69 and Comparative Examples 1 to 10 of the surface-treated metallic materials obtained by the above preparation methods were evaluated, and the coating adhesion of the overcoat film was evaluated. The results of evaluating the properties are also shown in Tables 2 to 5.

(Evaluation of Performance) The evaluation methods were as follows.

First, the evaluation of the film will be described.

The conductivity of the coating was evaluated by measuring the surface resistance (unit: Ω) of the test material using Loresta (Mitsubishi Chemical surface resistance measuring device). Therefore, the smaller the numerical value, the better the conductivity. The numerical values in Tables 2 to 5 are 10
The average of the measurements was used.

The corrosion resistance of the film was measured by spraying 5% saline solution at 35 ° C. while sealing the end face and back face of the test material.
The white rust occurrence area ratio after 0 hour was evaluated out of 10 points. The test portion was a “flat portion”, a “processed portion” extruded to 7 mm by an Erichsen tester, and a test plate sprayed with an alkaline degreaser (Surf Cleaner 53, manufactured by Nippon Paint Co., Ltd.) at 60 ° C. for 2 minutes. Degreased section ". The evaluation criteria are as follows. 10 points: No white rust occurred 9 points: White rust generation area was less than 5% 8 points: 5% to less than 10% 7 points: 10% to less than 20% 6 points: 20% to less than 30% 5 points : 30% to less than 40% 4 points: 40% to less than 50% 3 points: 50% to less than 70% 2 points: 70% to less than 90% 1 point: 90% or more Solvent resistance of the coating After placing the test plate on a rubbing tester, gauze impregnated with ethanol was applied at 0.5 kgf / c.
After pressing the test plate with a load of m ² and reciprocating 10 times,
The state of the film on the surface of the test plate was observed. Kerosene was also carried out in the same manner as above except that the number of reciprocations was changed to 50 times. The evaluation criteria are as follows. ：: No trace on the rubbed surface ○: Slight trace on the rubbed surface △: White trace on the rubbed surface ×: No film on the rubbed surface explain.

The coating adhesion was evaluated by a secondary adhesion test.

In the secondary adhesion test, the test plate was placed in boiling water for 30 minutes.
After immersion for one minute, the following three items were evaluated: grid, Erichsen, and grid + Eriksen.

The items of the grid are cut into 100 square grids of 1 mm on the test plate, and then an adhesive tape (Nichiban cellophane tape) is applied to the grid, and the tape is peeled off to determine the tape releasability according to the following criteria. The evaluation was made out of 10 points.

The Ericksen item was obtained by processing a part of the test plate surface using an Erichsen tester so as to protrude by 7 mm, attaching an adhesive tape, and performing the same evaluation as the above-mentioned cross-cut items. is there.

The items of the grid and the Erichsen are formed in advance by forming a grid and then using an Erichsen tester to process the grid-forming portion so as to protrude by 7 mm, sticking an adhesive tape to the protruding portion, The same evaluation as the item of the eye was performed.

The evaluation criteria for all three items are as follows. 10 points: no peeling 9 points: coating film residual rate is 90% or more 8 points: 80% or more 7 points: 70% or more 6 points: 60% or more 5 points: 50% or more 4 points: 40% 3 points: 30% or more 2 points: 20% or more 1 point: 10% or more 0 points: 0 to less than 10%

According to the metal surface treatment agent, the metal surface treatment method and the surface treated metal material of the present invention, the metal surface treatment agent used is an aqueous dispersion resin having a solid content of 5 to 30%.
% By mass, 1 to 10% by mass of silica fine particles, and 0.02% of at least one compound selected from an organic inhibitor group consisting of a urea compound, a guanidine compound, a phosphonate compound, a thiophosphate compound, a phosphine oxide compound and a phosphine sulfide compound. ~
An aqueous composition containing 5% by mass and 0.01 to 0.5% by mass of phosphate ions, wherein the aqueous dispersion resin is an ethylene-unsaturated carboxylic acid containing 10 to 30% by mass of an unsaturated carboxylic acid. 30% or more of the carboxyl group of the polymer is neutralized with potassium ions, and the resulting aqueous dispersion is obtained by reacting an ionomer resin and an epoxy compound which are dispersed in water. Has excellent conductivity, and excellent coating adhesion when a topcoat film is formed on the film.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C09D 123/26 C09D 123/26 133/00 133/00 157/00 157/00 163/00 163/00 167/00 167 / 00 175/04 175/04 C23C 22/00 C23C 22/00 Z 28/00 28/00 A F term (reference) 4D075 AE03 CA13 CA22 CA33 DA06 DB02 DB05 DC01 DC11 DC18 DC38 EA06 EB13 EB22 EB35 EB38 EB56 EC03 4J038 CB061 CB161 CG031 CG141 CH121 DB031 DB061 DB091 DB111 DB451 DD041 DG051 DG061 DG271 DG281 DG291 GA09 GA15 GA16 HA416 HA446 JB20 JB24 JC22 JC23 JC28 KA05 KA08 KA20 MA08 MA10 NA03 NA12 NA20 CA02 A03 CA03 A02 CA02 A02 CA02 A02 CA02 AB02 BA10 BA14 BA17 BA21 BB01 BB03 BB04 BB11 BC02 BC04 BC14 CA11 CA16 CA18 CA53

Claims (7)

[Claims] 1. An aqueous dispersion resin having a solid content concentration of 5 to 30% by mass, silica fine particles of 1 to 10% by mass, a urea compound,
0.02 to 5% by mass of at least one compound selected from the group of organic inhibitors consisting of a guanidine compound, a phosphonate compound, a thiophosphate compound, a phosphine oxide compound and a phosphine sulfide compound; In an aqueous composition containing 0.5% by mass, the aqueous dispersion resin uses potassium ions to form 30% or more of the carboxyl groups of an ethylene-unsaturated carboxylic acid copolymer containing 10 to 30% by mass of unsaturated carboxylic acid. A metal surface treatment agent, which is an aqueous dispersion obtained by reacting an ionomer resin and an epoxy compound which have been neutralized with water and dispersed in water. 2. The metal surface treating agent according to claim 1, comprising a composite aqueous dispersion resin obtained by radical polymerization of an unsaturated monomer in the presence of the aqueous dispersion resin. 3. The metal surface treating agent according to claim 1, further comprising at least one aqueous resin selected from an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acrylic resin. . 4. A composite obtained by radical polymerization of an unsaturated monomer in a mixture of the aqueous dispersion resin and at least one aqueous resin selected from an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acrylic resin. 2. The metal surface treating agent according to claim 1, comprising an aqueous dispersion resin mixture. 5. A metal surface treatment method comprising applying the metal surface treatment agent according to claim 1 to the surface of a metal material to form a film. 6. The metal surface treatment method according to claim 5, wherein a top coat is further applied on the film to form a coating film. 7. A surface-treated metal material obtained by the metal surface treatment method according to claim 5. Description: