CN1240468A - Metal surface treatment composition containing acrylic resin, method for treatment, and treated metal materials - Google Patents

Abstract

A metal surface treatment composition which can improve the corrosion resistance and the tight adhesion to coating films and impart slipperiness. The composition is an aqueous solution, dispersion or emulsion characterized by containing both an acrylic resin having amino and/or ammonium groups, hydroxyl groups and hydrophobic groups and a heavy metal or a salt thereof. The amino or ammonium groups have at least one structure selected from among those represented by general formulae (I) (wherein R1, R2: hydrogen, hydroxyl, substituted or unsubstituted, linear or branched C1-C5 alkyl, or substituted or unsubstituted, linear or branched C1-C5 hydroxyalkyl) and (II) (wherein R3, R4, R5: hydrogen, hydroxyl, substituted or unsubstituted, linear or branched C1-C5 alkyl, or substituted or unsubstituted, linear or branched C1-C5 hydroxyalkyl).

Description

Metal surface treatment composition containing acrylic resin, treatment method and finished metal material

technical field

The present invention relates to a metal surface treatment composition containing an acrylic resin, a treatment method and a metal material after final treatment, in particular to an acrylic resin containing a Resin metal surface treatment composition, treatment method and metal material after final treatment.

Background technique

The surface treatment of metal materials such as food cans, automobile bodies, steel coil coatings, building materials, etc., is carried out with phosphate treatment, chromate treatment or non-chromate treatment in the prior art. For example, when coating an organic film such as a paint or an adhesive on a metal surface such as iron, zinc, or aluminum, a phosphate film is first formed on the metal surface by phosphate treatment as a pretreatment. Then, by coating an organic film such as paint on it, corrosion resistance and coating adhesion can be improved. However, the metal surface treatment compositions in the conventional phosphate treatment method etc. are not necessarily satisfactory in terms of corrosion resistance, coating film adhesion or slidability in response to recent requirements.

Therefore, in order to try to further improve the corrosion resistance, a method of applying a primer after the phosphate treatment and then applying a paint is generally employed. However, if the primer is applied, although the corrosion resistance and the adhesion of the coating film are improved, the number of painting steps is increased, making the work complicated, and there are also problems such as an increase in the painting cost.

Therefore, as a metal surface treatment agent for the purpose of imparting high corrosion resistance and coating film adhesion and omitting primer coating, someone has proposed a "metal surface treatment agent for forming a composite film" such as Japanese Patent Laid-Open No. 5-117869. "Scheme. According to the disclosure, the metal surface treatment agent in the above-mentioned patent bulletin is composed of a phosphate surface treatment solution, which contains a cationic organic polymer compound or its salt containing more than one cationic nitrogen atom and a molecular weight of 1,000 to 1,000,000. .

In addition, in "Surface Treatment Method of Aluminum and Its Alloys" in JP-A-51-73938, it is disclosed that the metals to be subjected to surface treatment are limited to aluminum and the like, and the metals for the purpose of imparting corrosion resistance and coating film adhesion are disclosed. surface treatment. According to records, this metal surface treatment method uses an organic polymer film-forming substance containing a water-soluble resin such as vinyl acetate, vinylidene chloride, or acrylic acid or an emulsion resin and a water-soluble titanium compound as the main components. treatment fluid.

However, the above-mentioned metal surface treatment agents or treatment methods have not yet reached the level required in recent years, although they have improved corrosion resistance and coating film adhesion as compared with the prior art metal surface treatment agents.

In particular, in the case of food cans made of aluminum or its alloys, the above-mentioned metal surface treatment agents and the like cannot prevent seizing, and there is a problem of lack of lubricity when coating a steel sheet coil.

invention disclosure

The object of the present invention is to provide a metal surface treatment composition containing an acrylic resin capable of improving corrosion resistance or coating film adhesion and further imparting lubricity, a treatment method and a treated metal material.

In order to achieve the above object, the metal surface treatment composition containing acrylic resin involved in the present invention is any one of water-soluble, water-dispersible or emulsion, and contains at least one amino or ammonium group-containing Any of the acrylic resins containing hydroxyl and hydrophobic groups, as well as heavy metals or their salts.

Therefore, an inorganic film composed of a heavy metal or a salt thereof suppresses water permeability, thereby improving corrosion resistance. Furthermore, since the amino group or ammonium group in the acrylic resin coordinates with the (heavy) metal, the above-mentioned inorganic films are connected to each other through the acrylic resin. Therefore, coagulation failure of the inorganic film can be prevented, and an almost uniform film for undercoating can be formed on the metal surface. Therefore, the adhesion between the film for undercoating and the top coating film is also improved. The coating film for a coating base in the present invention refers to a coating composed of the above-mentioned inorganic coating formed on a metal surface and linked by an acrylic resin. Furthermore, since the above-mentioned acrylic resin is present almost uniformly on the surface of the undercoat film, frictional resistance can be reduced and lubricity can be improved.

(式中，R₁、R₂是氢，羟基，1～5个碳的有取代或无取代的直链或枝链的烷基，或1～5个碳的有取代或无取代的直链或枝链的羟烷基)，

(式中，R₃、R₄、R₅是氢，羟基，1～5个碳的有取代或无取代的直链或枝链的烷基，或1～5个碳的有取代或无取代的直链或枝链的羟烷基)。More preferably, the metal surface treatment composition containing acrylic resin according to the present invention is that the amino group or ammonium group in the acrylic resin has at least the structure shown in the following chemical formula (I) or (II):

(In the formula, R ₁ and R ₂ are hydrogen, hydroxyl, substituted or unsubstituted straight chain or branched chain alkyl with 1 to 5 carbons, or substituted or unsubstituted straight chain with 1 to 5 carbons or branched hydroxyalkyl),

(wherein, R ₃ , R ₄ , and R ₅ are hydrogen, hydroxyl, substituted or unsubstituted linear or branched chain alkyl groups with 1 to 5 carbons, or substituted or unsubstituted alkyl groups with 1 to 5 carbons straight-chain or branched-chain hydroxyalkyl).

In addition, the molecular weight of the acrylic resin in the present invention is 500-100,000, preferably 1,000-20,000. When molecular weight is less than 500, corrosion resistance will fall. On the other hand, when the molecular weight exceeds 100,000, hydrophilicity will decrease.

Furthermore, in the present invention, the content of the acrylic resin is 0.01 to 10 g/l, preferably 0.1 to 5 g/l, relative to the metal surface treatment composition. When the content of acrylic acid is less than 0.01 g/l, the binder effect cannot be exhibited, and the physical durability of the coating film for undercoating is reduced. On the other hand, when the content of the acrylic resin exceeds 10 g/l, the adhesiveness between the film for undercoating and the metal surface will decrease.

Furthermore, the metal surface treatment composition containing an acrylic resin according to the present invention is one in which the acrylic resin contains 1 to 10 amino and/or ammonium groups, 1 to 10 hydroxyl groups and 1 to 5 hydrophobic groups per 1000 molecular weight. In the case of less than 1 amino and/or ammonium group per 1000 molecular weight, the hydrophilicity and adhesion to metals are reduced; on the other hand, if the amino and/or ammonium group is more than 10 per 1000 molecular weight , the corrosion resistance decreases.

On the other hand, in the case of containing less than 1 hydroxyl group per 1000 molecular weight, hydrophilicity and coating film adhesiveness are lowered. On the other hand, when the number of hydroxyl groups contained per 1000 molecules exceeds 10, the corrosion resistance decreases. Furthermore, when the hydrophobic group contained per 1000 molecular weight is less than 1, corrosion resistance and lubricity will fall. On the other hand, in the case where the number of hydrophobic groups per 1000 molecular weight exceeds 5, hydrophilicity and coating film adhesion decrease.

In addition, in the metal surface treatment composition containing an acrylic resin, the amino group or ammonium group contained in the acrylic resin is introduced by copolymerizing at least a monomer represented by the following chemical formula (III) or (IV): (wherein, R ₆ is hydrogen or methyl,

R ₇ and R ₈ are hydrogen, hydroxyl, substituted or unsubstituted linear or branched chain alkyl with 1 to 5 carbons, or substituted or unsubstituted straight or branched chain with 1 to 5 carbons Hydroxyalkyl,

R ₉ is an alkylene group with 1 to 5 carbons), (wherein, R ₁₀ is hydrogen or methyl,

R ₁₁ and R ₁₂ are hydrogen, hydroxyl, substituted or unsubstituted straight or branched chain alkyl with 1 to 5 carbons, or substituted or unsubstituted straight or branched chain with 1 to 5 carbons Hydroxyalkyl,

R ₁₃ is an alkylene group having 1 to 5 carbons).

(式中，R₁₄是1～4个碳的亚烷基，Furthermore, in the metal surface treatment composition containing an acrylic resin according to the present invention, the hydroxyl group contained in the acrylic resin is introduced by copolymerizing at least a monomer having a structure represented by the following chemical formula (V):

(wherein, R ₁₄ is an alkylene group with 1 to 4 carbons,

R ₁₅ is hydrogen or methyl).

Furthermore, in the metal surface treatment composition containing acrylic resin involved in the present invention, the hydrophobic group contained in the acrylic resin is introduced by copolymerizing at least a monomer having a structure represented by the following chemical formula (VI): (In the formula, R ₁₆ is a linear, branched or cyclic alkyl group with 4 to 18 carbons, and R ₁₇ is hydrogen or methyl).

The acrylic resin in the acrylic resin-containing metal surface treatment composition of the present invention is preferably a copolymer of the following monomers. That is, (1) Examples of acrylic monomers containing an amino group (ammonium group) include N,N-dimethylaminoethyl (meth)acrylate and N,N-diethylaminoethyl (meth)acrylate. , (meth)acrylamide, N,N-dimethylacrylamide, N-methylolacrylamide, N-methylaminopropyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, N-ethylaminopropyl (meth)acrylamide, N,N-diethylaminopropyl (meth)acrylamide, chloride salts of these, and the like.

(2) Examples of acrylic monomers containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth) 2,3-dihydroxypropyl acrylate, etc.

(3) As a monomer containing a hydrophobic group, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, (meth)acrylate, base) 2-ethylhexyl acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, styrene, p-tert Butylstyrene, vinyltoluene, vinylphenol, benzyl (meth)acrylate, etc.

(4) Further, examples of monomers that may be further added include acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylonitrile, and the like.

The copolymerization ratio of the copolymer of above-mentioned monomer composition is: the acrylic acid monomer that contains amino group (ammonium group) is 5～60% (weight), the acrylic acid monomer that contains hydroxyl is 20～80% (weight), the acrylic acid monomer that contains hydrophobic group The content of the monomer is 5-50% by weight, and the content of other monomers is 0-30% by weight. Preferably, the acrylic monomer containing amino group (ammonium group) is 20-40% (weight), the acrylic monomer containing hydroxyl group is 30-60% (weight), and the monomer containing hydrophobic group is 20-40%. (weight).

In the above-mentioned copolymer, when the copolymerization ratio of the acrylic monomer containing amino group (ammonium group) is less than 5% by weight, the hydrophilicity will decrease, and the connection between the acrylic resin and the inorganic film composed of heavy metal or its salt will be reduced. sex decline. On the other hand, if the copolymerization ratio of the amino group (ammonium group)-containing acrylic monomer in the above-mentioned copolymer exceeds 60% by weight, the corrosion resistance will decrease.

In addition, when the copolymerization ratio of the hydroxyl group-containing acrylic monomer in the above-mentioned copolymer is less than 20% by weight, hydrophilicity and coating film adhesiveness will be lowered. On the other hand, when the copolymerization ratio of the hydroxyl group-containing acrylic monomer in the above-mentioned copolymer exceeds 80% by weight, the corrosion resistance decreases.

Furthermore, when the copolymerization ratio of the hydrophobic group-containing monomer in the above-mentioned copolymer is less than 5% by weight, the lubricity and corrosion resistance are lowered. On the other hand, when the copolymerization ratio of the hydrophobic group-containing monomer in the above-mentioned copolymer exceeds 50% by weight, hydrophilicity and coating film adhesion are lowered.

heavy metal

In addition, in the metal surface treatment composition containing acrylic resin according to the present invention, the heavy metal is zirconium (Zr), molybdenum (Mo), tungsten (W), niobium (Nb), nickel (Ni), cobalt (Co) , manganese (Mn), and tantalum (Ta) at least one. The supply source of the above-mentioned heavy metal is preferably a complex fluoride of the above-mentioned heavy metal, and other examples include nitrates and phosphates.

The content of the heavy metal complex fluoride is preferably 0.01 to 10 g/l relative to the metal surface treatment composition containing an acrylic resin according to the present invention. When the content of the heavy metal complex fluoride is less than 0.01 g/l, the corrosion resistance decreases. On the other hand, when the content of the heavy metal complex fluoride exceeds 10 g/l, the corrosion resistance also decreases.

The acrylic resin-containing metal surface treatment composition according to the present invention may further contain phosphoric acid or a phosphate. Examples of phosphoric acid or phosphate include H ₃ PO ₄ , Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , (NH ₄ ) ₃ PO ₄ , and the like. The content of phosphoric acid or phosphate is 0.01-20 g/l, preferably 0.05-0.1 g/l, relative to the metal surface treatment composition containing acrylic resin. When content of phosphoric acid or a phosphate is less than 0.01g/l, corrosion resistance will fall. When the content of phosphoric acid or phosphate exceeds 20 g/l, the adhesion of the coating film will decrease.

The metal surface treatment composition containing an acrylic resin according to the present invention may further contain the following etchant or etching aid as necessary.

etchant

Examples of the etchant include fluorides and salts thereof. Furthermore, such an etchant may be contained at 0.005 to 0.5 g/l with respect to the metal surface treatment composition. When the content of the etchant is less than 0.005 g/l, the etchantability is insufficient, and the coating film for undercoating cannot be satisfactorily formed on the metal surface. On the other hand, if the content of the etchant exceeds 0.5 g/l, etching will be excessive.

Etching aid

Examples of the etching aid include hydrogen peroxide (H ₂ O ₂ ), nitrous acid (HNO ₃ ), HBF ₄ and salts thereof. And the hydrogen peroxide (H ₂ O ₂ ), nitrous acid (HNO ₂ ) or their salts in the etching aid may also contain 0.005-5 g/l relative to the metal surface treatment composition. When content is less than 0.005 g/l, corrosion resistance will fall. On the other hand, even if the content exceeds 5 g/l, the corrosion resistance decreases. Furthermore, it is preferable to contain HBF ₄ or its salt in a range of 0.003 to 0.2 g/l with respect to the metal surface treatment composition. When content is less than 0.003 g/l, corrosion resistance will fall. On the other hand, even if the content exceeds 0.2 g/l, the corrosion resistance decreases.

Processing conditions and processing methods

The metal surface treatment method according to the present invention is to make the above-mentioned metal surface treatment composition containing acrylic resin contact the metal surface, then rinse with water and dry. In addition, the pH of the above-mentioned metal surface treatment composition is about 2.0-5.0, preferably 2.5-3.5. At this time, pH adjustment is performed with NaOH, an aqueous ammonia solution, nitric acid, or the like. The contact temperature between the metal surface treatment composition of the present invention and the metal material is normal temperature (eg 20°C) to 90°C, preferably 35 to 65°C. Generally, the contact time between a metal material and the acrylic resin-containing metal surface treatment composition of the present invention is shorter as the contact temperature is higher.

In the case of spray coating a metal material, the contact with the composition of the present invention is generally about 5 seconds to 5 minutes, preferably 10 to 60 seconds. In the case of the dipping method, a longer contact time than the above-mentioned contact time is required. In addition, it can also be contacted by a flow coating method or a roll coating method.

As described above, the surface-treated metal material is washed with water and then subjected to a drying step. The drying temperature is 150 to 240°C, and when the drying temperature is lower than 150°C, the corrosion resistance decreases. With regard to the water washing, after the metal material is in contact with the composition of the present invention, the surface-treated metal material is washed with water to remove the composition of the present invention that has not become a chemical conversion film. According to the present invention, an inorganic-organic conversion film can be obtained by a one-step treatment process.

Furthermore, the surface-treated metal material according to the present invention is characterized by being surface-treated with the above-mentioned acrylic resin-containing metal surface treatment composition.

best form of invention

Examples and comparative examples are given below to specifically describe the present invention.

Examples 1-11 and Comparative Examples 1-3

(1) Objects to be processed

Formed cans obtained by subjecting Al-Mn-based (JIS-A3004) aluminum alloy sheets to DI processing, etc.

(2) Evaluation method of surface treatment film

a) Resistance to blackening in boiling water

The boiling water blackening here refers to the phenomenon that the raw materials of the uncoated part interact with the metal in the water and turn black when the food cans are treated with boiling water such as tap water for sterilization. Blackness is the tolerance to this phenomenon.

The metal materials surface-treated with the compositions of the present examples and comparative examples were immersed in boiling tap water for 30 minutes, and the appearance was evaluated according to the following criteria.

○: No change in appearance

△: Slightly darkened

×: turn black

b) Lubricity of surface treatment film surface

The metal material surface-treated by the method of this embodiment was measured on a "HEIDON-14 type" testing machine with a 5mm steel ball, a load of 50g, and a stylus speed of 300mm/min to measure the coefficient of dynamic friction.

○: 0.6 or less

△: 0.6～0.8

×: When exceeding 0.8

c) Adhesion of outer coating film

Coatings manufactured by BASF Co., Ltd. (EB-70-001 N 150 mg/m ² /EB-69-002 N 60 mg/m ² ) were applied to the treated metal material with a bar coater. Then, the metal material coated in this way was subjected to wedge-shaped bending, and the bent portion was peeled off in a band shape using a Sello-Tape machine manufactured by Nichiban Co., Ltd., and the coating film peeling evaluation at this time was performed according to the following criteria.

○: Tape peeling width is less than 15mm

△: Tape peeling width 15-20mm

×: Tape peeling width exceeds 20mm

(3) Metal surface treatment conditions

(Example 1)

Al-Mn based (JIS-A 3004) molded tanks were degreased with 30g/l concentration of acidic degreasing agent ("SurfCleaner NHC 250", manufactured by Japan Paint Co., Ltd.) at 75°C for 60 seconds and then washed with water. Then, 0.5 g/l of the water-soluble acrylic resin shown in Table 1 was dissolved in an aqueous solution diluted to 20 g/l of a zirconium phosphate-based treatment agent ("Alsurf 440" manufactured by Japan Paint Co., Ltd.) to prepare the metal surface treatment composition of the present invention. , spray treatment with this composition at 50°C for 20 seconds. Then, it was rinsed with tap water, and heat-dried at 190° C. for 2 minutes. The evaluation results are listed in Table 3.

(Examples 2-11 and Comparative Examples 1-3)

Embodiments 2-11 and comparative examples 1-3 are that the water-soluble acrylic resin shown in Table 1 and the heavy metal complex fluoride are prepared metal surface treatment compositions by the compounding amount shown in Table 2, and then use these compositions according to the above-mentioned Embodiment 1 carries out surface treatment. The evaluation results are listed in Table 3. Table 1

                                                                       ,

Types of clustering types together (weight ratio) molecular weight (MN) A-1 NVP/DMAPAA/NBA 60/20/20 3000A-2 NVP/DMAEA/ST 50/30/20 6000A-3 NVP/Dmapma/EHA/HEA 30 /30/30/10 4000A-4 Viz/DMAAM/LMA 40/30/30 5000A-5 VP/DMAAM/EHA 30/40/30 3000B 1 HEA/NBA 80/20 8000B-2 HEMAPMA 80/200/200 4000 note) HEA: 2-hydroxyethyl acrylate HEMA: 2-hydroxyethyl methacrylate HBA: 4-hydroxybutyl acrylate DMAEA: N,N-dimethylaminoethyl acrylate DMAEMA: N methacrylic acid, N-Dimethylaminoethyl Ester DMAPAA: N,N-Dimethylaminopropyl Acrylamide DMAPMA: N,N-Dimethylaminopropyl Methacrylamide NBA: n-Butyl Acrylate EHA: 2-Ethyl Acrylate Hexyl Hexyl CHMA: Cyclohexyl Methacrylate LMA: Lauryl Methacrylate SMA: Stearyl Methacrylate TBMA: Tert-Butyl Methacrylate Table 2

  Water-soluble acrylic resin   Heavy metal compounds

Type Content (g/l) Type Content (g/l)

1 A-1 0.5 ALSURF 440 20 real 2 A-2 0.1 ALSURF 440 20

3 A-3 1.0 ALSURF 440 20 Shi 4 A-4 0.5 ALSURF 440 20

5 A-5 0.5 ALSURF 440 20 cases 6 A-1 0.5 (NH4)2ZrF6 1

7 A-1 5.0 ALSURF 440 20-1 B-1 0.5 ALSURF 440 20 Compared with 2 B-2 0.5 ALSURF 440 20 cases 3--Alsurf 440 20 Note: ALSURF 440: phosphate processing agent, Japanese Paint Company watch 3 watch 3 watch 3 watch 3 watch 3 watchmaking 3

Evaluation results

  Resistance to blackening in boiling water   Lubricity   Adhesion of outer coating film

1 ○ ○ ○ ○ Real 2 ○ ○ ○ ○

3 ○ ○ ○ ○Shi 4 ○ ○ ○ ○

5 ○ ○ ○ ○case 6 ○ ○ ○ ○

7 ○ ○ ○ ○ ○ ○ vs. 1 × × × × 2 ○ ○ × × ○ Example 3 △ × ×

From these results, it can be seen that the composition for metal surface treatment according to the present invention has improved any one of properties of boiling water blackening resistance, lubricity, and coating film adhesion as compared with the prior art.

Possibility of industrial application

According to the metal surface treatment composition of the present invention, since the inorganic film composed of heavy metal or its salt can suppress water permeability, corrosion resistance is improved. In addition, the amino group (ammonium group) in the acrylic resin coordinates with the (heavy) metal, so that the above-mentioned inorganic film is connected to each other through the acrylic resin. Therefore, it is possible to form an almost uniform undercoating film on the metal surface while preventing aggregation and destruction of the inorganic film. Therefore, the adhesiveness of the film for undercoatings and the overcoat film is also improved. Here, the film for undercoating refers to a film composed of the above-mentioned inorganic film bonded by an acrylic resin formed on the metal surface. In addition, since the above-mentioned acrylic resin is present almost uniformly on the surface of the undercoat film, frictional resistance can be reduced and lubricity can be improved.

Therefore, according to the metal surface treatment composition of the present invention, it is possible to remarkably improve corrosion resistance or coating film adhesion, and further impart lubricity compared with the prior art. In addition, according to the metal surface treatment composition of the present invention, in the case of producing food cans made of aluminum or its alloys, jamming can be prevented, and lubricity can be imparted during coil coating.

Furthermore, the metal surface treatment composition of the present invention can be used for metal surface treatment of food cans, automobile bodies, steel sheet coil coating, building materials and the like.

Claims (27)

1. The metal surface treatment composition containing acrylic resin, characterized in that it is any one of water-soluble, water-dispersible or emulsion, and contains at least any one of amino group or ammonium group and hydroxyl group and hydrophobic-based acrylic resins, as well as heavy metals or their salts. 2. the metal surface treatment composition containing acrylic resin, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 1, the amino group or ammonium group in the described acrylic resin has following chemical formula (I) at least Or the structure shown in (II),

(In the formula, R ₁ and R ₂ are hydrogen, hydroxyl, substituted or unsubstituted straight chain or branched chain alkyl with 1 to 5 carbons, or substituted or unsubstituted straight chain with 1 to 5 carbons or branched hydroxyalkyl), (wherein, R ₃ , R ₄ , and R ₅ are hydrogen, hydroxyl, substituted or unsubstituted linear or branched chain alkyl groups with 1 to 5 carbons, or substituted or unsubstituted alkyl groups with 1 to 5 carbons straight-chain or branched-chain hydroxyalkyl). 3. The metal surface treatment composition containing an acrylic resin, characterized in that, in the metal surface treatment composition containing an acrylic resin according to claim 1 or claim 2, the acrylic resin contains 1 to 10 per 1000 molecular weight from At least one selected from amino groups and ammonium groups, 1 to 10 hydroxyl groups, and 1 to 5 hydrophobic groups. 4. A metal surface treatment composition, characterized in that, in the metal surface treatment composition containing an acrylic resin according to claim 1 or claim 2, the molecular weight of the acrylic resin is 500 to 100,000. 5. metal surface treatment composition, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 1 or claim 2, with respect to described metal surface treatment composition, the content of acrylic resin is 0.01～10g/l. 6. metal surface treatment composition, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 1 or claim 2, with respect to described metal surface treatment composition, the content of acrylic resin is 0.1～5g/l. 7. The metal surface treatment composition containing acrylic resin, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 1, the amino or ammonium group contained in the acrylic resin is obtained by making at least the following The monomer copolymerization of the structure shown in chemical formula (III) or (IV) introduces,

(wherein, R ₆ is hydrogen or methyl, R ₇ and R ₈ are hydrogen, hydroxyl, substituted or unsubstituted linear or branched chain alkyl with 1 to 5 carbons, or substituted or unsubstituted straight or branched chain with 1 to 5 carbons Hydroxyalkyl, R ₉ is an alkylene group with 1 to 5 carbons),

(wherein, R ₁₀ is hydrogen or methyl, R ₁₁ and R ₁₂ are hydrogen, hydroxyl, substituted or unsubstituted straight or branched chain alkyl with 1 to 5 carbons, or substituted or unsubstituted straight or branched chain with 1 to 5 carbons Hydroxyalkyl, R ₁₃ is an alkylene group having 1 to 5 carbons). 8. The metal surface treatment composition containing acrylic resin, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 1, at least one of the hydroxyl groups contained in the acrylic resin is obtained by making the following chemical formula (V) introduced by copolymerization of monomers of the structure shown,

(wherein, R ₁₄ is an alkylene group with 1 to 4 carbons, R ₁₅ is hydrogen or methyl). 9. The metal surface treatment composition containing acrylic resin, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 1, at least one of the hydrophobic groups contained in the acrylic resin is obtained by making The monomer copolymerization of the structure shown in the following chemical formula (VI) introduces,

(In the formula, R ₁₆ is a linear, branched or cyclic alkyl group with 4 to 18 carbons, and R ₁₇ is hydrogen or methyl). 10. The metal surface treatment composition containing acrylic resin, characterized in that, in the metal surface treatment composition containing acrylic resin according to claim 1, the monomer copolymerization ratio of the acrylic resin copolymer constituting the acrylic resin is, The acrylic acid monomer containing amino group and/or ammonium group is 5-60% (weight), the acrylic acid monomer containing hydroxyl group is 20-80% (weight), and the monomer containing hydrophobic group is 5-50% (weight), Other monomers are 0 to 30% by weight. 11. The metal surface treatment composition containing acrylic resin, characterized in that, in the metal surface treatment composition containing acrylic resin according to claim 1, the acrylic resin copolymer constituting the acrylic resin contains amino and/or ammonium 20-40% (weight) of acrylic monomers containing hydroxyl groups, 30-60% (weight) of acrylic monomers containing hydroxyl groups, and 20-40% (weight) of monomers containing hydrophobic groups. 12. The metal surface treatment composition containing acrylic resin, characterized in that, in the metal surface treatment composition containing acrylic resin according to claim 1, the heavy metal is zirconium, molybdenum, tungsten, niobium, nickel, cobalt, manganese , At least one of tantalum. 13. A metal surface treatment composition, characterized in that, in the metal surface treatment composition containing an acrylic resin according to claim 1, the heavy metal is at least one of zirconium, niobium, manganese, and tantalum. 14. Metal surface treatment composition, it is characterized in that, in the metal surface treatment composition that contains acrylic resin described in claim 12 or claim 13, the supply source of heavy metal is each complex fluoride, nitrate, phosphoric acid of this heavy metal at least one of salt. 15. The metal surface treatment composition is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 12 or claim 13, with respect to the metal surface treatment composition, the heavy metal complex fluoride The content is 0.01～10g/l. 16. A metal surface treatment composition, characterized in that the acrylic resin-containing metal surface treatment composition according to any one of claims 1 to 15 further contains at least one of phosphoric acid or a phosphate salt. 17. Metal surface treatment composition, characterized in that, in the metal surface treatment composition containing acrylic resin according to claim 16, the phosphoric acid or phosphate is H ₃ PO ₄ , Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , (NH ₄ ) ₃ PO ₄ , etc. 18. Metal surface treatment composition, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 16, with respect to described metal surface treatment composition, the content of phosphoric acid or phosphate is 0.01～ 20g/l. 19. A metal surface treatment composition, characterized in that an etchant is further contained in the acrylic resin-containing metal surface treatment composition according to any one of claims 1 to 15. 20. A metal surface treatment composition, wherein, in the acrylic resin-containing metal surface treatment composition according to claim 19, the etchant is at least any one of hydrogen fluoride or a salt thereof. 21. Metal surface treatment composition, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 19, the content of described etchant, relative to the metal surface treatment composition of the present invention, is 0.005～5g/l. 22. A metal surface treatment composition, characterized in that an etching aid is further contained in the acrylic resin-containing metal surface treatment composition according to any one of claims 1 to 15. 23. metal surface treatment composition, it is characterized in that, in the metal surface treatment composition that contains acrylic resin described in claim 22, described etching auxiliary agent is at least any of hydrogen peroxide, nitrous acid, HBF ₄ and its salt A sort of. 24. Metal surface treatment composition, it is characterized in that, in the metal surface treatment composition containing acrylic resin according to claim 23, the content of the hydrogen peroxide, nitrous acid or its salt is relative to the metal surface treatment composition In terms of substances, it is 0.005~5g/l. 25. Metal surface treatment composition, it is characterized in that, in the metal surface treatment composition containing acrylic resin described in claim 23, the content of said HBF ₄ or its salt is relative to the metal surface treatment composition of the present invention It is 0.003 to 0.2 g/l. 26. A metal surface treatment method, characterized in that the acrylic resin-containing metal surface treatment composition according to any one of claims 1 to 25 is brought into contact with the metal surface, followed by washing with water and drying. 27. A surface-treated metal material, which is characterized in that it has been surface-treated with the metal surface treatment composition containing an acrylic resin according to any one of claims 1 to 25.