JP2002265821A - Ground-treating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chromium-free ground-treating agent capable of imparting a sufficient adhesion to a laminate film, and also excellent in coating work efficiency and stability. SOLUTION: This ground-treating agent contains a water soluble zirconium compound, water soluble or water-dispersing acrylic resin and water soluble or water-dispersing thermosetting type cross-linking agent. The above water soluble zirconium compound is 50-15,000 ppm in a mass base as zirconium, and the above acrylic resin has 150-740 mgKOH/g solid portion acid value and 24-240 solid portion hydroxyl value, and is 500-30,000 ppm in the mass base as a solid portion. The above thermosetting type cross-linking agent is 125-7,500 ppm in the mass base as a solid portion. The above ground-treating agent is characterized by that it is used for the production of the laminate film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a surface treatment agent,
The present invention relates to a base treating agent for aluminum or an aluminum alloy having improved adhesion of a laminate film.

[0002]

2. Description of the Related Art In general, a laminated film is formed by mounting a plastic film made of polyethylene terephthalate, polyethylene naphthalate, another polyester resin or the like on the surface of a thin plate material and bonding them by heat and pressure. Such a laminated film is different from a coating material in which a base material is coated with a paint or the like, and the generation of a solvent or carbon dioxide during baking is considerably reduced, and the workability is good.
Furthermore, in drinking can applications, no environmental hormones are generated,
Due to the good flavor of the contents and the like, applications are expanding, and for example, they are used for bodies and lids of beverage and food cans, dry battery containers, and the like.

As an example of a thin plate material used as a material of a laminated metal material, for example, a metal plate such as aluminum or an aluminum alloy can be cited. Such a metal plate is usually preliminarily subjected to a degreasing treatment and then a base treatment for imparting adhesion.

Conventionally, a phosphoric acid chromate-based surface treatment agent has been used for the surface treatment of a laminated metal material. In recent years, however, there has been a demand for environmental protection and a need for adaptation to products that are subjected to advanced processing. Because of the increase, there is a need for a non-chromium-based surface treatment agent that does not use a chromium compound and that can impart higher adhesion to a laminated metal material than ever before.

[0005] As a non-chromium-based primer, Polya
An underlayer blended with crylic acid and a water-soluble zirconium compound
Treatment agents are commercially available, for example, US Pat. No. 4,545,545.
No. 842, U.S. Pat. No. 4,191,596.
Is polyacrylic acid and H_Two ZrF ₆ Alumini consisting of
Of aluminum and its alloys is disclosed.
You. However, this primer has a laminating property
It is not sufficient for use as a thin film.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a non-chromium base treating agent which imparts sufficient adhesion to a laminated metal material, and is excellent in coating workability and stability. I do.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an undercoating agent comprising a water-soluble zirconium compound, a water-soluble or water-dispersible acrylic resin, and a water-soluble or water-dispersible thermosetting crosslinker. The conductive zirconium compound is 500 to 15000 ppm by mass as zirconium, and the acrylic resin has a solid content acid value of 150 to 740 m
gKOH / g and a solid content hydroxyl value of 24 to 240, and 500 to 30,000 ppm by mass as a solid content.
The thermosetting cross-linking agent is 125 to 7500 ppm on a mass basis as a solid content, and the undercoating agent is
An undercoating agent characterized in that it is used for manufacturing a laminated metal material. The water-soluble or water-dispersible thermosetting crosslinking agent is preferably a condensate of melamine, formaldehyde and an alkyl monoalcohol having 1 to 4 carbon atoms, and / or a condensate of phenolic acid and formaldehyde. The present invention is also aluminum or an aluminum alloy, at least one surface of which is treated with the above-mentioned underlayer treating agent. The present invention further provides a water-soluble zirconium compound as zirconium in an amount of 0.8 to 35 mg / m ² , on at least one surface, by mass per one surface after drying.
Water-soluble or water-dispersible acrylic resin as a solid content of 1 to 6
Aluminum or an aluminum alloy, wherein a film containing 0 mg / m ² and 0.25 to 15 mg / m ² as a solid content of a water-soluble or water-dispersible thermosetting crosslinking agent is formed. Hereinafter, the present invention will be described in detail.

The undercoating agent of the present invention contains a water-soluble zirconium compound, a water-soluble or water-dispersible acrylic resin, and a water-soluble or water-dispersible thermosetting crosslinking agent. The water-soluble zirconium compound is not particularly limited as long as it is a compound containing zirconium. For example, H ₂ ZrF
₆ , (NH ₄ ) ₂ ZrF ₆ , (NH ₄ ) ₂ ZrO (CO
₃ ) _{2 and the} like; H ₂ ZrF ₆ , (NH ₄ ) ₂ Zr
O (CO ₃ ) ₂ is preferred.

The above-mentioned water-soluble zirconium compound is used as the zirconium in the undercoating agent of the present invention in an amount of 500 to 500 parts by mass.
15000 ppm. If it is less than 500 ppm,
Adhesion and anticorrosion of the laminated metal material are reduced and 1500
If it exceeds 0 ppm, the adhesion will be reduced and the cost will be increased.

The water-soluble or water-dispersible acrylic resin contained in the undercoating agent of the present invention has a solid content hydroxyl value of 24 to 24.
0. If it is less than 24, the adhesion and corrosion resistance of the laminated metal material will be reduced, and if it is more than 240, the stability over time of the obtained acrylic resin will be reduced. Preferably, 30 to
200, and more preferably 40-140.

The acrylic resin has a solid content acid value of 150.
７740 mg KOH / g. 150mgKOH / g
If the amount is less than 740 m, the water solubility is reduced and the appearance of the film is reduced, and the adhesion of the laminated metal material is also reduced to 740 m
If it exceeds gKOH / g, the necessary hydroxyl value described above cannot be obtained. Preferably, it is 200 to 700 mgKOH / g, more preferably, 300 to 650 mgKOH / g.
It is.

The acrylic resin has a number average molecular weight of 25.
It is preferably from 00 to 50,000. If it is less than 2500, the curability is not sufficient, and if it exceeds 50,000, the viscosity of the obtained base treating agent increases, and the coating workability and storage stability deteriorate. More preferably, 6000-2
0000. In the present specification, the molecular weight is determined by a GPC method using a styrene polymer as a standard.

The acrylic resin can be obtained by radically polymerizing an ethylenically unsaturated monomer. The ethylenically unsaturated monomer is not particularly limited, but includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, allyl alcohol and Methacryl alcohol, 2-hydroxyethyl (meth) acrylate and ε-
Hydroxyl-containing ethylenically unsaturated monomers such as adducts with caprolactone; (meth) acrylic acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, acrylic acid dimer, and ε-caprolactone adduct of acrylic acid; Derivatives; unsaturated dibasic acids such as maleic acid, fumaric acid, itaconic acid and the like and ethylenically unsaturated monomers having a carboxyl group such as half esters, half amides and half thioesters; (meth) acrylamide, N
-Methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dibutyl (meth)
Acrylamide, N, N-dioctyl (meth) acrylamide, N-monobutyl (meth) acrylamide, N-
Amide group-containing ethylenically unsaturated monomers such as monooctyl (meth) acrylamide;

The acrylic resin further includes methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl (meth) acrylate, and lauryl. (Meth) acrylates such as methacrylate, phenyl acrylate, isobornyl (meth) acrylate, cyclohexyl methacrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentadienyl (meth) acrylate and dihydrodicyclopentadienyl (meth) acrylate Ester monomers; polymerizable aromatic compounds such as styrene, α-methylstyrene, vinyl ketone, t-butylstyrene, parachlorostyrene, and vinylnaphthalene; acrylonitrile And polymerizable nitriles such as methacrylonitrile, ethylene, alpha-olefin such as propylene, vinyl acetate, vinyl esters of vinyl propionate and the like; butadiene, it is possible to use other monomers diene such isoprene. The above-mentioned ethylenically unsaturated monomers and other monomers can be used alone or in combination of two or more.

As a polymerization method for obtaining the acrylic resin, a general method described in known literature such as solution radical polymerization can be used. For example, a polymerization temperature of 60 to
A method in which an appropriate radical polymerization initiator and a monomer mixture solution are added dropwise to an appropriate solvent at 160 ° C. over 2 to 10 hours while stirring is used.

The above-mentioned acrylic resin is used in an amount of 500 to 30,000 ppm as a solid content in the undercoating agent of the present invention.
It is. If it is less than 500 ppm, the adhesion and anticorrosion of the laminated metal material will be reduced, and if it exceeds 30,000 ppm, the viscosity of the resulting base treatment agent will be increased, making it difficult to handle, and the laminated metal material suitable for the compounding amount. Performance cannot be improved, and the cost increases.

The base treating agent of the present invention may contain a base resin other than the above acrylic resin. The other base resin is not particularly limited, and examples thereof include a polyester resin, an alkyd resin, an epoxy resin, and a urethane resin, and one or more of them can be used in combination.

The water-soluble or water-dispersible thermosetting crosslinking agent contained in the undercoating agent of the present invention is not particularly limited, and examples thereof include a water-soluble melamine resin and a water-soluble phenol resin. As the water-soluble melamine resin, for example,
"Nikalac MX-035" (70% non-volatile content) and "Nikalac MX-042" (70% non-volatile content) manufactured by Sanwa Chemical Co., Ltd. can be used. The water-soluble melamine resin is preferably a condensate of melamine, formaldehyde and an alkyl monoalcohol having 1 to 4 carbon atoms.

Examples of the water-soluble phenol resin include, for example, "SHONOL BRL-157" manufactured by Showa Polymer Co., Ltd.
(43% non-volatile content) and “Shaunol BRL-141”
B "(45% non-volatile content)," Regitop 4012 "(38% non-volatile content) manufactured by Gunei Chemical Co., and the like can be used. As the water-soluble phenol resin, a condensate of carboxylate and formaldehyde is preferable.

The water-soluble or water-dispersible thermosetting crosslinking agent is used as a solid component in the undercoating agent of the present invention in an amount of 1% by mass.
25 to 7500 ppm. If it is less than 125 ppm, the adhesion and corrosion resistance of the laminated metal material are reduced, and
If it exceeds 00 ppm, the adhesion of the laminated metal material will not be improved in proportion to the compounding amount, and the cost will increase.

The above-mentioned zirconium compound, acrylic resin and thermosetting crosslinking agent may be used alone or in combination of two or more. The surface treatment agent of the present invention may further contain, if necessary, additives such as a stabilizer, an antioxidant, a surface conditioner, and an antifoaming agent used in a general surface treatment agent. .

Since the water-soluble or water-dispersible zirconium compound, acrylic resin, and thermosetting crosslinking agent are used as the undercoating agent of the present invention, there is no need to include a solvent, and the aqueous solution or the aqueous dispersion can be used. Can be prepared as By using a solventless type surface treatment agent, the amount of the solvent released into the atmosphere can be eliminated, thereby contributing to environmental conservation, painting work safety, and the like.

The undercoating agent of the present invention can be produced by a conventionally known method such as mixing and stirring the above-mentioned acrylic resin, thermosetting crosslinking agent, zirconium compound, and additives used as necessary. Can be.

The undercoating agent thus obtained is used for producing a laminated metal material. The method for producing the laminated metal material is not particularly limited. For example, a normal laminating method can be used. For example, a thin plate made of metal or the like is subjected to a degreasing treatment and, if necessary, washed with water and pickled. After the surface is adjusted, a method is used in which a film made of a thermoplastic resin or the like is adhered to a substrate obtained by treating with the base treating agent of the present invention and drying by heating.

As the thin plate material to be used as the material of the laminated metal material, for example, a metal plate material is used, and one made of aluminum or an aluminum alloy is preferable.
004 material, aluminum alloy 3005 material, etc .; aluminum alloy 5052 material, aluminum alloy 5182 material, etc. as beverage / food can lid material; aluminum alloy 1050 material, aluminum alloy 1100 material, etc. are preferably used as dry battery containers.

The degreasing treatment is not particularly limited, and for example, a method used for treating a normal aluminum substrate or aluminum alloy substrate such as alkali degreasing cleaning can be used. The degreasing treatment is usually performed by a spray method. After performing the above-described degreasing treatment, in order to remove the degreasing agent remaining on the substrate surface, after performing a water-washing treatment, draining with a roll, air blowing or hot air drying, etc., the moisture on the substrate surface is removed. Is removed.

Obtained by the treatment with the undercoating agent of the present invention
The amount of the film to be coated is, for example, the weight per one side after drying,
0.8 of water-soluble zirconium compound as zirconium
~ 35mg / m^Two , Water-soluble or water-dispersible acrylic resin
1 to 60 mg / m as solid content ^Two And thermosetting crosslinking
1 to 70 mg / m as the total solid content of the agent^Two , Zirconium
0.8 to 35 mg / m2 as zirconium in the compound
^Two Is preferred.

The treatment with the undercoating agent of the present invention may be performed so that the weight of the film to be formed is within the above range, and the treatment method using the undercoating agent is not particularly limited.
For example, a roll coating method, a dipping method, a spray method, or the like can be used. Preferably, a roll coating method is used.
The treatment with the underlayer treating agent of the present invention depends on the use of the laminated metal material, but may be performed on at least one surface of the above-described thin plate material, and may be performed on both surfaces of the thin plate material.

As a method for drying a film obtained by the above-mentioned undercoating agent, drying by heating is performed, and examples thereof include oven drying and / or heating drying by forced circulation of hot air. 60-180 ° C
For 6 to 60 seconds.

The method for adhering the film to the base material thus obtained is not particularly limited. For example, a method usually used for lamination can be used. There is a method in which the sheet is placed, heated and pressed with a heating roller at 150 to 250 ° C. for 0.1 second to 10 seconds, and bonded.
Further, if necessary, after the film is pressed, the film can be reheated (remelt, 5 seconds to 60 seconds) to near the softening point of the film (180 to 260 ° C.). As the film, for example, a film usually used for lamination can be used, and examples thereof include a film made of a thermoplastic resin such as polyethylene terephthalate, polyethylene naphthalate, and other polyesters.

The undercoating agent of the present invention contains a specific amount of the above-mentioned zirconium compound, acrylic resin and thermosetting crosslinking agent, so that it is excellent in coating workability and stability, and the obtained laminated metal material has sufficient adhesion. Has the property. Therefore, the underlayer treating agent of the present invention is suitably used for the production of a laminated metal material, and is particularly suitably used for the production of a laminated metal material which requires high adhesion and water resistance after advanced processing.

[0032]

EXAMPLES The present invention will be further described below with reference to Production Examples and Examples.
Although described in detail, the present invention is limited to only these examples.
It is not something to be done. Parts are parts by weight, and% is weight
Represents%.Synthesis Example 1 Synthesis of Acrylic Resin A  775 parts of ion-exchanged water was added to a four-necked
And the contents are stirred and refluxed with nitrogen.
Heated to 0 ° C. Then, heat, stir and reflux with nitrogen
While 120 parts of acrylic acid and 20 parts of ethyl acrylate
And a mixture of 60 parts of 2-hydroxyethyl methacrylate
Nomer liquid, 1.6 parts of ammonium persulfate and
A mixture of 23.4 parts of on-exchange water was added to each dropping funnel.
And dripped over 3 hours. After dropping, heat and stir
Stirring and nitrogen reflux were continued for 2 hours. Stop heating and nitrogen reflux
The solution to 30 ° C while stirring, and
Filtration with a comb, colorless and transparent water-soluble acrylic resin A
An aqueous solution was obtained. The obtained acrylic resin A aqueous solution is non-volatile
Emission 20%, Acid value of resin solids 467, hydroxyl group of resin solids
The number was 129 and the number average molecular weight was 9,200.

[0033]Synthesis Example 2 Synthesis of acrylic resin B  The monomer composition of the acrylic resin, 160 parts of acrylic acid,
20 parts of ethyl acrylate, 2-hydroxy methacrylate
The same procedure as in Synthesis Example 1 was performed except that ethyl was used in 20 parts.
A colorless and transparent acrylic resin B aqueous solution was obtained in this order. Get
The aqueous solution of the acrylic resin B obtained has a non-volatile content of 20%,
Form acid value 623, resin solids hydroxyl value 43, number average molecule
The amount was 8,400.

[0034]Synthesis Example 3 Synthesis of Acrylic Resin C  The monomer composition of the acrylic resin, acrylic acid 150 parts,
40 parts of ethyl acrylate, 2-hydroxy methacrylate
Procedure similar to Synthesis Example 1, except that 10 parts of ethyl was used.
A colorless and transparent acrylic resin C aqueous solution was obtained. Obtained
Acrylic resin C aqueous solution has a nonvolatile content of 20%, resin solid
Acid value 584, Resin solid content hydroxyl value 22, Number average molecular weight
8700.

[0035]Synthesis Example 4 Synthesis of Acrylic Resin D  The monomer composition of the acrylic resin was changed to 30 parts of acrylic acid,
70 parts of ethyl acrylate, 2-hydroxyethyl methacrylate
The same procedure as in Synthesis Example 1 was performed except that the chill was 100 parts.
An acrylic resin was synthesized in this order. Besse synthetic resin
The liquid became cloudy at around 60 ° C during cooling in
While adding 28.3 parts of 25% ammonia as a neutralizing agent.
Added. Cool to 30 ° C, light red-brown acrylic resin D
An aqueous solution was obtained. The resulting acrylic resin D aqueous solution is non-volatile
Departure 19.4%, resin solid content acid value 117, resin solid content water
The acid value was 216 and the number average molecular weight was 11600.

[0036]Examples 1 to 20, Comparative Examples 1 to 10  (Preparation of base treatment agent) Deionize water with a stirrer
The solution obtained in the synthesis example was charged into the cell and stirred at room temperature.
Add an aqueous solution of krill resin gradually, and stir
The crosslinking agent was gradually added. While stirring, zirconi
Compound is gradually added, and stirring is continued for 20 minutes.
A solvent type primer was obtained. Acrylic resin aqueous solution used
And the solid content of thermosetting crosslinker based on mass
Amount (ppm), type of zirconium compound and Z
Table 1 shows the compounding amount (ppm) based on mass as r.
Show. Thermosetting cross-linking agents are used as water-soluble phenolic resins.
Showa Polymer Co., Ltd. "Shownol BRL-157" (non-volatile
43%), Sanwa Chemical as a water-soluble melamine resin
"Nikarac MX-035" (nonvolatile content 70%)
Using. The zirconium compound is manufactured by Nippon Light Metal Co., Ltd.
Hydrogen zirconium (containing 17.58% as Zr) or
Is manufactured by Daiichi Kagaku Kagaku Kogyo_Four )_Two ZrO (CO
_Three )_Two (Product name, Zircosol AC-7, 1 as Zr
3%).

(Preparation of base treated plate) Aluminum alloy 3
004 plate material, Nippon Paint Co., Ltd. "Surf cleaner 3
Degreased using a 30% 2% diluent (treated at 65 ° C. for 3 seconds), and the base material obtained above was applied to the obtained aluminum material using a reverse roll coater, and the wet weight before drying per one surface was obtained. And apply to 10 g / m ² with
It was dried at a raw material temperature of 80 ° C. using a conveyor type oven to obtain a base treated plate. Film weight after drying (mg / m
² ) is shown in Table 1 with the solid content weight of the acrylic resin and the thermosetting crosslinking agent as the organic component, and the weight of zirconium in the zirconium compound as Zr. (Preparation of laminated board) A polyethylene terephthalate (PET) film is placed on the obtained substrate-treated plate, and pressed using a heating roller at a roll temperature of 180 ° C. and a roll speed of 30 m / min. And bonded for 60 seconds to obtain a laminate.

(Evaluation method) The following evaluations were performed, and the results are shown in Table 1.
It was shown to. 1. Chemical conversion agent stability The undercoating agent prepared as described above was stored at 40 ° C for 30 days, and the appearance of the treatment solution was visually evaluated. In Table 1, those having good appearance without any abnormality such as turbidity, sedimentation, and presence or absence of aggregates are represented by “○”, and those having abnormality are represented by the state. 2. Film appearance The surface of the base treated plate obtained as described above was visually evaluated. In Table 1, those having a good appearance without any abnormality such as repelling, dent, side, and bumps are indicated by “○”, and those having abnormality are indicated by the state.

3. Adhesiveness of the laminated plate The following obtained (1)-
The tape peeling test was performed as in (6), and the adhesion was evaluated based on the number of grids that were not peeled off by the tape among the 100 grids before the tape was attached. (1) Flat surface / no treatment PET according to JIS K 5400.8.5.1
A cross-cut cross cut was made on the film attachment surface, and a tape peeling test was performed. (2) Flat surface / boiling water treatment The laminate was immersed in boiling water for 30 minutes, and a cross-cut cross cut was made on the surface to which the PET film was attached, and a tape peeling test was performed. (3) Flat surface / steam treatment The laminated plate was placed in pressurized steam at 125 ° C. and 1.13 atm for 30 minutes, and a cross-cut cross cut was made on the surface to which the PET film was attached to perform a tape peeling test.

(4) No Erichsen Processing / Treatment A cross cut was made on the surface of the laminated plate to which the PET film was attached, and the cut surface was extruded by 4 mm using an Erichsen extrusion tester to perform a tape peeling test. (5) Erichsen processing / boiling water treatment The laminate was immersed in boiling water for 30 minutes, a cross cut was cut on the PET film attachment surface, and the cut surface was extruded 4 m with an Erichsen extrusion tester to perform a tape peeling test. . (6) Erichsen processing / steam treatment The laminated plate was placed in pressurized steam at 125 ° C. and 1.13 atm for 30 minutes, a cross cut was made on the PET film pasting surface, and the cut surface was 4 mm using an Erichsen extruder. Extrusion and a tape peeling test were performed.

[0041]Comparative Example 11  Polyacrylic acid (resin solid acid) instead of acrylic resin
780 mgKOH / g, hydroxyl value 0, manufactured by Nippon Junyaku
Thermosetting cross-linking agent using "Jurimer AC-10H")
Except not to use the underlayer treatment, the same as in the first embodiment.
A physical agent was prepared, and a laminate plate was prepared and evaluated.

[0042]Comparative Example 12  Nippon Paint Co., Ltd.
Using Lusurf 401/45, Cr in dry film weight
20mg / m^Two Phosphoric acid chromate treatment
The same as in Example 1 except that
A laminate was prepared and evaluated as described above.

[0043]

[Table 1]

From Table 1, it can be seen that Comparative Examples 1 to 3, 6 to 10 in which an acrylic resin, a thermosetting crosslinking agent or a zirconium compound was used in a compounding amount not within the scope of the present invention, the acid value or hydroxyl value of the present invention. Comparative Examples 4 and 5 using acrylic resins not in the range, Comparative Example 11 using polyacrylic acid instead of acrylic resin, and Comparative Example 1 using phosphoric acid chromate treatment
The sample No. 2 was inferior in the evaluation of the Erichsen-treated laminate, and in some cases, the evaluation of the laminate not subjected to the Erichsen was also inferior. On the other hand, Examples using an acrylic resin, a thermosetting crosslinking agent and a zirconium compound each having an acid value and a hydroxyl value within the range of the present invention in a compounding amount within the range of the present invention, regardless of the presence or absence of Erichsen processing The laminate evaluation was found to be excellent.

[0045]

Since the undercoating agent of the present invention has the above-described structure, it is a non-chromium-based undercoating agent which imparts sufficient adhesion to the laminated metal material and is excellent in coating workability and stability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 161/28 C09D 161/28 F-term (Reference) 4F100 AA27A AB10B AB31B AK25A AK41C BA02 BA03 BA10B BA10C CA02A EH462 EJ422 EJ652 EJ862 GB16 JB09A JK06 4J038 CG141 CG171 DA062 DA162 GA03 GA06 HA126 HA306 KA03 MA08 MA09 MA10 NA12 NA23 PC02

Claims (4)

[Claims] An undercoating agent comprising a water-soluble zirconium compound, a water-soluble or water-dispersible acrylic resin, and a water-soluble or water-dispersible thermosetting crosslinker, wherein the water-soluble zirconium compound has a mass of zirconium. 50 by standard
0 to 15000 ppm, and the acrylic resin has a solid content acid value of 150 to 740 mgKOH / g and a solid content hydroxyl value of 24 to 240, and is 5% by mass as a solid content.
Wherein the thermosetting cross-linking agent is 125 to 7500 ppm by mass as a solid content, and the undercoating agent is used for producing a laminated metal material. Agent. 2. A water-soluble or water-dispersible thermosetting crosslinking agent,
The surface treating agent according to claim 1, which is a condensate of melamine, formaldehyde and an alkyl monoalcohol having 1 to 4 carbon atoms, and / or a condensate of carbonyl carbonate and formaldehyde. 3. An aluminum or aluminum alloy having at least one surface treated with the undercoating agent according to claim 1 or 2. 4. A water-soluble zirconium compound in an amount of 0.8 to 35 mg / m ² as zirconium and a water-soluble or water-dispersible acrylic resin in a solid content of 1 to 3 mass% on one side after drying. Aluminum or an aluminum alloy, wherein a film containing 60 mg / m ² and 0.25 to 15 mg / m ² as a solid content of a water-soluble or water-dispersible thermosetting crosslinking agent is formed.