JP2001009365A - Powder application method for metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a powder film layer excellent in adhesiveness and corrosion resistance, on the surface of a metallic material, by treating the metallic material, of which the surface has been treated with a phosphate solution, with an aqueous solution containing a component consisting of a specified phenol compound derivative, and drying it to be subjected to powder coating. SOLUTION: Before performing powder coating, a metallic material, of which the surface has been treated with a phosphate solution, is treated by using an aqueous solution containing a component consisting of one or more kinds of phenol compound derivatives having an average polymerization degree of 2-50 of one or more kinds of polymerization units represented by the formula, wherein X which is bonded to a benzene ring represents a hydrogen atom, a hydroxyl group, a 1-5C alkyl group, a 6-12C aryl group, a benzyl group, a benzal group, an unsaturated hydrocarbon group which condensates with a benzene ring to form a naphthalene ring, or the like. Subsequently, the treated metallic material is dried and subjected to powder coating, thereby forming a powder film layer excellent in adhesiveness and corrosion resistance, on the surface of the metallic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for powder coating a metal material having excellent adhesion and corrosion resistance.

[0002]

2. Description of the Related Art The characteristics of a powder coating and a powder coating method are as follows.
This is a coating method that has no VOC emissions and is highly efficient in terms of environmental friendliness and resource saving, with high use efficiency. However, since thin coating is difficult and a thick coating film is formed, shrinkage stress is generated when the coating film is cured, and sometimes a problem occurs in adhesion to the material surface. The measure to reduce the shrinkage stress depends on the resin design, but it also affects the physical properties of the coating film itself,
Not enough response. In addition, since it is difficult to incorporate a rust preventive pigment into a coating film, there is a problem that an inhibitory effect of suppressing corrosion from a defective portion of the coating film in a corrosive environment cannot be sufficiently expected.

In general, it is also known that the surface of a metal material is surface-treated with a metal phosphate and / or a metal oxide prior to painting in order to improve adhesion and corrosion resistance. Furthermore, in order to improve adhesion and corrosion resistance, the surface of the metal material was surface-treated with a metal phosphate and / or a metal oxide, and then treated with a chromic acid-based aqueous solution (post-treatment). Due to a number of environmental concerns, post-treatment with various aqueous solutions not containing chromic acid has been proposed. For example, JP-A-52-80239, JP-A-56-136979 and the like can be mentioned. JP-A-52-80239 describes post-treatment with a solution of a silane coupling agent.
JP-A-57-13679 describes that a post-treatment is carried out with a solution containing a chelating agent (quinolines, triazoles, pyrones and the like) as a main component. Both patent publications describe that the adhesion and corrosion resistance after coating are improved. However, in powder coating, adhesion and corrosion resistance are still insufficient.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for forming a powder coating film having excellent adhesion and corrosion resistance on the surface of a metal material. .

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on means for solving the problems of the prior art, and as a result, prior to powder coating, a compound represented by the following general formula (I): A component comprising one or more phenolic compound derivatives containing at least one kind of polymerized unit at an average degree of polymerization of 2 to 50:

[0006]

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Wherein X bonded to a benzene ring is a hydrogen atom, a hydroxyl group, a C1-C5 alkyl group, a C1-C5 hydroxyalkyl group, a C6-C12
An aryl group, a benzyl group, a benzal group, an unsaturated hydrocarbon group condensed to the benzene ring to form a naphthalene ring, or a group represented by the following formula (II):

[0008]

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Wherein R1 and R2 in the formula (II) are
Each independently of one another, a hydrogen atom, a hydroxyl group,
Represents a 1-C5 alkyl group or a C1-C10 hydroxyalkyl group, and in formulas (I) and (II), Y1 and Y2 bonded to the benzene ring are each independently the following formula (III) or ( IV) Z represented by
One of the groups:

[0010]

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Wherein R in the above formulas (III) and (IV) is
3, R4, R5, R6 and R7 are each independently a hydrogen atom, a C1-C10 alkyl group or a C1-
X represents a C10 hydroxyalkyl group, and each of X, Y1 and Y2 bonded to the benzene ring of the plurality of polymerized units is the same as each of X, Y1 and Y2 bonded to another benzene ring. And the average number of substitutions of the Z group in the benzene ring of the plurality of polymerized units is 0.2 to 1.0. ], It has been found that the adhesion and the corrosion resistance in a corrosive environment, which are problems of the powder coating film, can be improved.

[0012] Thus, the present invention provides a method for coating a metal material, wherein the metal material whose surface has been treated with a phosphating solution is treated with the aqueous solution and then powder-coated. It is.

Hereinafter, the coating method of the present invention will be described in more detail.

Examples of the metal material include zinc, iron, aluminum, magnesium, steel and alloys thereof, galvanized steel sheet, and the like. These include cold rolling, hot rolling, mold forming, grinding, and acid washing. May be processed. More specifically, the materials include building materials, electrical products, office equipment, automobile bodies, outer panels and parts.

In the present invention, these metallic materials are:
The surface is treated with a phosphating solution (hereinafter referred to as a treating solution). Specifically, for example, one or more metal salts selected from iron phosphate, manganese phosphate, zinc phosphate, and zinc phosphate containing ions of calcium, nickel, magnesium, cobalt and the like are used. Aqueous solutions or dispersions are preferred. The concentration of these metal salts can be arbitrarily selected depending on the purpose, but is usually preferably in the range of 1 to 30% by weight.

The method for surface-treating the metal material with these treatment solutions is not particularly limited, and any method known per se can be used. For example, the metal material may be treated with a phosphate aqueous solution or Immersed in an aqueous dispersion or
Alternatively, it is performed by spraying the metal product, but the former method is generally preferred. Preferably, the temperature of the aqueous phosphate solution or aqueous dispersion is usually in the range of 10 to 60 ° C. Thereafter, it is preferable to wash with water as necessary, and then to perform drainage drying at room temperature or by heating.

In the method of the present invention, one or more polymerized units represented by the following general formula (I) are added before powder coating on the metal material surface-treated with the phosphating solution as described above. Two
Component consisting of one or more phenolic compound derivatives with an average degree of polymerization of 50:

[0018]

Embedded image

Wherein X bonded to the benzene ring is a hydrogen atom, a hydroxyl group, a C1-C5 alkyl group, a C1-C5 hydroxyalkyl group, a C6-C12
An aryl group, a benzyl group, a benzal group, an unsaturated hydrocarbon group condensed to the benzene ring to form a naphthalene ring, or a group represented by the following formula (II):

[0020]

Embedded image

Wherein R1 and R2 in the formula (II) are
Each independently of one another, a hydrogen atom, a hydroxyl group,
Represents a 1-C5 alkyl group or a C1-C10 hydroxyalkyl group, and in the formulas (I) and (II), Y1 and Y2 bonded to the benzene ring are each independently the following formula (III) or ( One of the Z groups represented by IV):

[0022]

Embedded image

Wherein R in the above formulas (III) and (IV)
3, R4, R5, R6 and R7 are each independently a hydrogen atom, a C1-C10 alkyl group or a C1-
X represents a C10 hydroxyalkyl group, and each of X, Y1 and Y2 bonded to the benzene ring of the plurality of polymerized units is the same as each of X, Y1 and Y2 bonded to another benzene ring. And the average number of substitutions of the Z group in the benzene ring of the plurality of polymerized units is 0.2 to 1.0. ] (Hereinafter, referred to as a treatment liquid).

The phenolic compound derivative component used in the present invention is an oligomer or a polymer containing the polymerized unit represented by the above formula (I), and the polymerized unit of the formula (I) has an average degree of polymerization of 2 to 50.

In the formula (I), X bonded to the benzene ring is a hydroxyl group, a C1-C5 alkyl group,
For example, C1-C5 hydroxyalkyl groups such as methyl, ethyl and propyl groups, for example, hydroxymethyl, hydroxyethyl, hydroxypropyl groups and the like, C6-C12 aryl groups such as phenyl and naphthyl groups, benzyl group, benzal group, and the like An unsaturated hydrocarbon group fused to a benzene ring to form a naphthalene ring, ie, -CH = CH-CH = CH-, or = CH-CH =
CH—CH ＝ represents a group or a group represented by the formula (II).

In the formula (II), R1 and R2 each independently represent a hydrogen atom, a hydroxyl group, C1-C1
0 represents an alkyl group such as a methyl, ethyl and propyl group, or a C1 to C10 hydroxyalkyl group such as a hydroxymethyl, hydroxyethyl and hydroxypropyl group.

In the formulas (I) and (II), Y1 and Y2 bonded to the benzene ring each independently represent a hydrogen atom or a Z group represented by the formula (III) or (IV) . R3, R4, R5, R6 and R7 in the formulas (III) and (IV) each independently represent a C1 to C10 alkyl group such as a methyl, ethyl, propyl group or the like; Groups, such as hydroxymethyl, hydroxyethyl, and hydroxypropyl groups.

Each of X and Y1 in the formula (I) and Y2 in the formula (II), which are bonded to the benzene ring of a plurality of polymerized units in the polymer molecule, are linked to other benzene rings. It may be the same as each of X, Y1 and Y2 to which it is bound, or may be different from each other. Further, the average number of substitutions of the Z group in the benzene ring of a plurality of polymer units in the polymer molecule is 0.2 to 1.0. The average polymerization degree (n) of the polymerization unit of the formula (I) is 2 to 50. When the average degree of polymerization n is less than 2, the resulting polymer has an excessively low molecular weight, so that the corrosion resistance of the resulting film becomes insufficient, and when it exceeds 50, the resulting surface treatment composition, In addition, the stability of the aqueous treating solution containing the same is deteriorated, which causes practical problems.

The average value of the number of substitutions of the Z group means the Z value introduced into each benzene ring in the polymer molecule.
It is the average of the number of groups. For example, in the formula (I), when the degree of polymerization is 10, and X is a benzene ring-containing group of the formula (II), the number of benzene rings per molecule of the polymer is 20, and When one Z group is introduced into each of 10 benzene rings per molecule of the united polymer, the average Z group substitution number of this polymer is [(1 × 10) + (0
× 10)] / 20 = 0.5.

If the average value of the number of Z group substitution is less than 0.2, the resulting polymer becomes insufficient in water solubility and the stability of the treatment liquid becomes insufficient. From the formula (I), the average number of Z group substitutions does not become 1 or more.
When it exceeds 0, the water solubility of the obtained polymer becomes excessive,
The water solubility of the obtained surface treatment film becomes excessive, and the effect of improving the intended corrosion resistance becomes insufficient.

Z represented by the formulas (III) and (IV)
Each of R3 to R7 in the group represents a C1 to C10 alkyl group or a C1 to C10 hydroxyalkyl group. When the carbon number of these groups is 11 or more, the adhesion of the resulting surface-treated film is reduced, and the intended effect of improving corrosion resistance becomes insufficient.

The phenol compound derivative component used in the present invention can be obtained by reacting a generally known phenol compound derivative with formaldehyde and a secondary amine (Mannich reaction). If necessary, it can be neutralized with an organic acid or an inorganic acid to obtain a water-soluble or water-dispersible or emulsion. As the secondary amine, dimethylamine, diethylamine, diisopropylamine, dipropylamine,
Methylethylamine, methylpropylamine, methylisopropylamine, methylbutylamine, methylisobutylamine, ethylpropylamine, ethylisopropylamine, ethylbutylamine, ethylisobutylamine, ethylethanolamine, propylethanolamine, butylethanolamine, ethylpropanolamine, ethyl Isopropanolamine, ethylbutanolamine, ethylisobutanolamine, propylpropanolamine, isopropylisopropanolamine,
Examples thereof include, but are not particularly limited to, propylisopropanolamine, diethanolamine, dipropanolamine, and diisopropanolamine. Examples of the organic or inorganic acid used for the neutralization include formic acid, acetic acid, citric acid, oxalic acid, nitric acid, phosphoric acid, hydrofluoric acid, sulfuric acid, hydrochloric acid, boric acid, and the like, and one or more kinds can be used.

The post-processing method of the present invention will be described. In the method of the present invention, the pH of the treatment liquid is 2.0 to 2.0.
It can be in the range of 10.0, but it is usually preferred to keep it between 4.0 and 8.0 for solution stability and for best results on the treated metal surface. . In order to adjust the pH of the treatment solution to the above range, sodium hydroxide, potassium hydroxide, ammonium hydroxide, or the like may be added as necessary.

Further, the treatment liquid of the present invention is, for example, 0.0%
It is intended to be used in a dilute solution of 1 to 10.0% by weight, but a concentration of 0.1 to 5.0% is particularly preferred.

In the treatment stage, the treatment liquid is applied to the metal surface by a method known per se. For example, the solution of the treatment liquid can be applied by spray coating, roller coating or dipping. The temperature of the solution to be applied can vary over a wide range, but is preferably in the range of 20-70C. After application, the surface can be washed with water, but good results can be obtained without washing. Depending on the end use, washing with water is preferred.

Next, the treated metal product is dried. Drying is performed, for example, by circulating air or by oven drying. Room temperature drying can also be used, but it is preferable to employ a higher temperature in order to shorten the drying time.

After drying, the treated metal product is ready for powder coating.

In the method of the present invention, a powder coating is applied to the treating solution and the metal material treated with the treating solution as described above.

In the method of the present invention, the powder coating used can be a conventionally known powder coating without any particular limitation, for example, a thermosetting powder coating. As the thermosetting powder coating, for example, thermosetting epoxy resin powder coating, thermosetting polyester resin powder coating, and thermosetting vinyl resin powder coating can be suitably used.

Thermosetting epoxy resin powder coating: The epoxy resin used in the powder coating has an epoxy equivalent of about 20.
A powder resin having a molecular weight of 0 to 5000, a number average molecular weight of about 1000 to 80000, and a softening temperature of about 60 to 150 ° C can be used. Specifically, as a product name, for example, Epicoat 1
004, left 1002, left 1007 (all manufactured by Yuka Shell Epoxy Co., Ltd.), Araldite GY-608
4. Same as the left 6097 (manufactured by Ciba Geigy Corporation), DER-6
62, left 664, left 667 (manufactured by Dow Chemical Company)
Bisphenol-epichlorohydrin type epoxy resins, EPPN-201, 202, EOCN-102
Novolak type epoxy resin such as 102S (above, manufactured by Nippon Kayaku Co., Ltd.), epoxy group-containing vinyl polymer [for example, glycidyl (meth) acrylate, 3, 4
-Epoxycyclohexylmethyl (meth) acryle-
G, allyl glycidyl ether, glycidyl styryl ether, 4-vinylcyclohexene-1-oxide, 5
-Vinylbicyclo [2.2.1] hept-2-ene-2
A radical homopolymer of an epoxy group-containing unsaturated monomer such as an oxide or limonene monoxide, and if necessary, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate; ) Alkyl or cycloalkyl esters of (meth) acrylic acid such as acrylates, iso-butyl (meth) acrylates, cyclohexyl (meth) acrylates, and hydroxyl-containing compounds such as hydroxyethyl (meth) acrylates Saturated monomers, nitrile compounds such as (meth) acrylonitrile, aromatic vinyl monomers such as styrene and α-methylstyrene, and radical copolymers with other unsaturated monomers. Among these, bisphenol-epichlorohydrin type epoxy resins and novolak type epoxy resins are preferably used because of their excellent corrosion resistance and the like.

As the cross-linking agent for cross-linking the epoxy resin, any conventionally known cross-linking agent can be used as long as it cross-links and cures the epoxy group of the epoxy resin. Specifically, for example,
(Anhydrous) polycarboxylic acid compounds [adipic acid, dodecane diacid, (anhydrous) trimellitic acid, (anhydrous) succinic acid, etc.
Phenolic resin, dicyandiamide, etc.], aromatic dihydrazide [adipic dihydrazide, sebacic dihydrazide, etc.], cationic polymerization catalyst of aromatic sulfonium salt [benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl-4 -Methoxyphenylmethylsulfonium hexafluoroantimonate].

Mixing ratio of the above epoxy resin and crosslinking agent
Usually has an epoxy resin / crosslinking agent ratio of about 95/5 to
A range of 50/50 weight ratio is preferred. However, the above fragrance
When using a cationic polymerization catalyst for aromatic sulfonium salts
Is in the range of 99.99 / 0.01 to 90/10 weight ratio.
good. Thermosetting polyester resin powder coating: Used in the powder coating
Polyester resins include hydroxyl groups and / or
Polyester resin containing ruboxyl group can be used,
The xyl equivalent and / or the hydroxyl equivalent are 200 to 500.
0, the average molecular weight is about 500 to 50,000, and the softening temperature is
A powder resin at about 60-150 ° C can be used. The polyes
Ter resin is mainly composed of polybasic acid (or methyl ester)
Esterified with a divalent alcohol, for example, a lid
Acid, isophthalic acid, terephthalic acid, tetrahydro
Water) phthalic acid, hexahydro (anhydride) phthalic acid, isophthalic acid
Aromatic or dimethyl phthalate, dimethyl terephthalate, etc.
Is an aliphatic dicarboxylic acid compound and if necessary
Acid, sebacic acid, (anhydride) maleic acid, (anhydride) tri
Polysalts such as other polycarboxylic acid compounds such as merit acid
Ethylene glycol, propylene glycol, ne
Pentyl glycol, butanediol, 1,6-hexyl
Polyol compounds such as sandiol are converted to carboxyl groups and
And / or an esterification reaction having a hydroxyl group.
Can be used.

When the polyester resin has a carboxyl group, triglycidyl isocyanurate, the above-mentioned polyepoxy resin, the above-mentioned vinyl polymer containing an epoxy group, and the like can be used as a crosslinking agent for crosslinking the above-mentioned polyester resin. Can be Among them, bisphenol (A, F, or S) to epichlorohydrin type epoxy resin and novolak type epoxy resin are preferably used because they have excellent corrosion resistance and the like.

When the polyester resin has a hydroxyl group, examples thereof include block polyisocyanate (such as ε-caprolactam diisocyanate) and tetramethoxymethylglycoryl.

The mixing ratio of the polyester resin and the crosslinking agent is usually such that the ratio of the polyester resin / crosslinking agent is about 95%.
The range of / 5 to 50/50 weight ratio is preferred.

Thermosetting vinyl resin powder coating: The vinyl resin used in the above powder coating has a softening temperature of 40 to 150.
C, preferably in the range of 50 to 130C.

When the softening temperature is lower than 40 ° C., the coating has poor blocking resistance. On the other hand, when the softening temperature is higher than 150 ° C., the finished appearance (smoothness, etc.) of the coating film is not preferable. The number average molecular weight of the vinyl resin is in the range of 1500 to 15000, preferably 2500 to 6000. If the number average molecular weight is less than 1500, the blocking properties of the powder coating are poor, and the coating properties such as scratch resistance and weather resistance are poor. When the number average molecular weight exceeds 15,000, the finished appearance of the coating film is inferior, so that it is not preferable.

In the above vinyl resin, when the resin has an epoxy group (glycidyl group), a polycarboxylic acid (for example, an aliphatic dibasic acid shown below) is used as a crosslinking agent, and when the resin has a hydroxyl group, The block polyisocyanate crosslinking agent can be used.

As the epoxy group-containing vinyl resin, a resin obtained by polymerizing the above-mentioned epoxy group-containing vinyl monomer and the above-mentioned other unsaturated monomer in an appropriate combination is used. The proportion of the epoxy group-containing vinyl monomer constituting the vinyl resin is particularly preferably from 25 to 50% by weight. When the proportion of the epoxy group-containing vinyl monomer is less than 25% by weight, the abrasion resistance is inferior, and when it exceeds 50% by weight, the storage stability of the powder coating is inferior, and the finished appearance is also inferior.

The aliphatic dibasic acid which can be used as a crosslinking agent component of the epoxy group-containing vinyl resin is a saturated or unsaturated aliphatic dibasic acid having 2 or more carbon atoms. Specifically, for example, succinic acid, glutaric acid, adipic acid,
Pyromellitic acid, dodecane diacid, azelaic acid, sebacic acid, brassic acid, itaconic acid, maleic acid, citraconic acid, eicosane diacid and one or two of these
More than one kind of acid anhydride and the like can be mentioned. Of these, dodecane diacid and its anhydride are particularly preferred. As the hydroxyl group-containing vinyl resin, a radical copolymer of the hydroxyl group-containing unsaturated monomer and the other unsaturated monomer can be used. These can be used in combination with the block polyisocyanate crosslinking agent.

The mixing ratio of the vinyl resin and the crosslinking agent is usually such that the ratio of the vinyl resin / crosslinking agent is 95/5 to 5/5.
A 0/50 weight ratio is preferred.

The powder coating can be applied by a known powder coating method, preferably an electrostatic powder coating method, for example, a corona charging method, a tribocharging method or the like. The powder coating thickness is usually about 20-100 μm, preferably about 3 μm.
A range from 0 to 80 μm is preferred.

The baking of the powder coating varies depending on the type of the powder coating.
This can be performed in a range of about 0 seconds to about 40 minutes.

[0054]

Next, the present invention will be specifically described with reference to examples and comparative examples. “Parts” and “%” indicate “parts by weight” and “% by weight”, respectively.

The present invention is not limited by these embodiments.

The method for testing the coating film performance of the test plates prepared in Examples and Comparative Examples will be described.

(1) Corrosion resistance The test material in which the coating film was cut to reach the substrate was heated at 50 ° C.
After being immersed in a 5% NaCl aqueous solution for 240 hours, the peeling width of the coating film from the cut portion with cellotape was measured. (Maximum peeling width on one side from cut part: mm) (2) Water resistance After immersing the test material in pure water at 40 ° C. for 240 hours, 2 mm
100 squares were cut in four directions and peeled off by cellophane, and the number of remaining coating films after peeling was evaluated.

(3) Adhesion The test material in which an H-shaped cut reaching the base material was put on the coating film,
The appearance of the coating film after bending along a φ20 mm pipe was evaluated (visually).

：: No abnormality ×: Coating cracks and peeling [Treatment liquid composition] The composition of the treatment liquid (post-treatment liquid) used in the present invention is shown in Table 1.

F of the processing solution is X = -H, Y1 = CH2N
(CH3) 2, n = 1, the average number of substituted Z groups was 1.00, the concentration of the polymer component was 1.0%, and the pH was 4.5. As the processing liquid G, Baren-60A (10 g / L, a chromic acid aqueous solution, manufactured by Nippon Bakery Liquid Co., Ltd.) was used.

The treatment liquids A to F were used at a liquid temperature of 40 ° C. and G was used at a normal temperature.

[0062]

[Table 1]

[Powder Coating] [Production Example of Thermosetting Powder Coating] (a) Epoxy resin powder coating: Epicoat 1004 (trade name, Bisphenol A to Epichlorohydrin, manufactured by Yuka Shell Epoxy Co., Ltd.) Epoxy resin, softening temperature 70
C., number average molecular weight 1400) A mixture of 940 parts of 940 parts, adipic dihydrazide 60 parts and titanium white pigment 400 parts was dry-blended, melt-kneaded and dispersed with a busconider, and then cooled, coarsely ground and finely ground. It was manufactured by performing 150 mesh filtration.

(B) Polyester resin powder coating (block polyisocyanate crosslinked): Finedec M80
31 (manufactured by Dainippon Ink Co., Ltd., trade name, softening temperature 70
C., 770 parts of a hydroxyl value of 30 mg KOH / g), 230 parts of .epsilon.-caprolactam blocked isophorone diisocyanate (blocked polyisocyanate crosslinking agent) and 400 parts of titanium white were dry blended with a Henschel mixer, and then busconi. The mixture was melt-mixed and dispersed in a kneader, cooled, coarsely pulverized, and finely pulverized, and then filtered through a 150 mesh to produce.

(C) Vinyl resin powder coating: vinyl copolymer (glycidyl methacrylate / n-butyl methacrylate / methyl methacrylate / styrene = 35/1)
800 parts of a 5/35/15 weight ratio, a softening temperature of 67 ° C., a number average molecular weight of 3,000), 200 parts of dodecane diacid, and 400 parts of titanium white are dry-blended at room temperature using a Henschel mixer, and extruded. It was melt-kneaded. This was cooled, finely pulverized by a pin disk mill, and coarse particles were separated by a 150-mesh sieve to obtain a powder coating.

(D) Polyester resin powder coating (epoxy resin curing agent): Finedec M8860 (trade name, manufactured by Dainippon Ink Co., Ltd., acid value 35, softening temperature 60)
° C, number average molecular weight 2000 powder) 700 parts, epico-
To 1002 (Yukaka Epoxy Co., Ltd., trade name,
Epoxy equivalent 550-700, average about 2 epoxy groups)
300 parts and 400 parts of titanium white were dry-blended with a Henschel mixer, melt-mixed and dispersed with a busconider kneader, cooled, coarsely ground and finely ground.
It was manufactured by filtration through 0 mesh.

The above-mentioned various thermosetting powder coatings were applied to a surface-treated steel sheet shown in Table 2 using an electrostatic powder coating machine (manufactured by Gemma Co., Ltd.) to a thickness of 50 μm. Then at 180 ° C for 20
After baking for a minute, a powder cured film was formed.

[Examples 1 to 8] Fine-cleaner L4460 (A agent: 20 g / L, B agent: 12 g / L) was prepared by using a cold-rolled steel sheet (0.8 × 300 × 100 mm size) as a metal material. (An alkaline degreaser manufactured by Nippon Parkerizing Co., Ltd.) was spray-degreased at 43 ° C. for 120 seconds, and then pure water was sprayed at room temperature for 30 seconds and washed with water. Next, Preparen ZN (1.0 g / L) (manufactured by Nippon Parker Zinc Co., Ltd., titanium colloid-based surface conditioner)
Was sprayed at room temperature for 30 seconds. This cold-rolled steel sheet is immersed in a zinc phosphate surface treatment agent (manufactured by Nippon Parkerizing Co., Ltd., Palbond L3020) (treatment agent) heated to 43 ° C for 120 seconds, pulled up, and then deionized with pure water at room temperature. Sprayed for 30 seconds and washed with water. Then, it was immersed in the treatment solution shown in Table 2 for 30 seconds, pulled up, sprayed with pure water at room temperature for 30 seconds, washed with water, and dried at 80 ° C. for 180 seconds. The steel sheet thus surface-treated was used in Examples shown in Table 2.

[Examples 9 to 10] Using a cold-rolled steel sheet (0.8 x 300 x 100 mm size) as a metal material, Fine Cleaner L4460 (A agent: 20 g / L, B agent: 12 g / L) ( Spray degreasing at 43 ° C for 120 seconds, and then spray pure water at room temperature for 30 seconds.
And washed with water. Next, Preparen ZN (1.0 g / L) (a titanium colloid-based surface conditioner manufactured by Nippon Parkerizing Co., Ltd.) was sprayed at room temperature for 30 seconds.

This cold-rolled steel sheet was heated to 43 ° C. by using an iron phosphate surface treating agent (manufactured by Nippon Parkerizing Co., Ltd.,
1077) (treating agent), immersed in the solution for 120 seconds, pulled up, sprayed pure water at room temperature for 30 seconds, and washed with water. Then immersed in the treatment solution shown in Table 2 for 30 seconds, lifted it,
Pure water was sprayed at room temperature for 30 seconds, washed with water, and dried at 80 ° C. for 180 seconds. The steel sheet thus surface-treated was used in Examples shown in Table 2.

[Examples 11 to 12] Using a galvannealed steel sheet (GA, 0.8 x 300 x 100 mm size II) as a metal material, Fine Cleaner-L4460 (A agent: 20 g /
Agents L and B: 12 g / L) (Alkaline degreaser, manufactured by Nippon Bakery Liquid Co., Ltd.) were spray-degreased at 43 ° C. for 120 seconds, and then pure water was sprayed at room temperature for 30 seconds and washed with water. Then, Preparen ZN (1.0 g / L) (manufactured by Nippon Parkerizing Co., Ltd., titanium colloid II-based surface conditioner) was added at room temperature for 30 minutes.
Sprayed for 2 seconds. This cold-rolled steel sheet was immersed in a zinc phosphate surface treatment agent (manufactured by Nippon Parkerizing Co., Palbond-L3020) (treatment agent) heated to 43 ° C for 120 seconds, pulled up, and then purified water was allowed to stand at room temperature. For 30 seconds and washed with water.
Then, it was immersed in the treatment solution shown in Table 2 for 30 seconds, pulled up, sprayed with pure water at room temperature for 30 seconds, washed with water, and then washed at 80 ° C for 18 seconds.
Dry for 0 seconds. The steel sheet thus surface-treated was used in Examples shown in Table 2.

Comparative Example 1 A cold-rolled steel sheet (0.
Spray Fine Cleaner-L4460 (A agent: 20 g / L, B agent: 12 g / L) (Nippon Parkerizing Co., Ltd., alkaline degreasing agent) at 43 ° C for 120 seconds using 8 x 300 x 100 mm size II). -Degrease, then spray pure water at room temperature for 30 seconds,
Washed with water. Then, Preparen ZN (1.0 g / L) (Titanium Colloid II surface conditioner, manufactured by Nippon Parkerizing Co., Ltd.) was sprayed at room temperature for 30 seconds. This cold-rolled steel sheet was immersed in a zinc phosphate surface treatment agent (manufactured by Nippon Parkerizing Co., Palbond-L3020) (treatment agent) heated to 43 ° C for 120 seconds, pulled up, and then purified water was allowed to stand at room temperature. For 30 seconds and washed with water. Then, it was immersed in the treatment solution shown in Table 2 for 30 seconds, pulled up, sprayed with pure water at room temperature for 30 seconds, and washed with water.
It was dried at 80 ° C. for 180 seconds. The steel sheet thus surface-treated was used in Comparative Examples shown in Table 2.

Comparative Example 2 A cold rolled steel sheet (0.
Spray Fine Cleaner-L4460 (A agent: 20 g / L, B agent: 12 g / L) (Nippon Parkerizing Co., Ltd., alkaline degreasing agent) at 43 ° C for 120 seconds using 8 x 300 x 100 mm size II). -Degreased, then sprayed with pure water at room temperature for 30 seconds and washed with water. Then, Preparen ZN (1.0 g / L) (Titanium Colloid II surface conditioner, manufactured by Nippon Parkerizing Co., Ltd.) was sprayed at room temperature for 30 seconds. This cold-rolled steel sheet was heated to 43 ° C using an iron phosphate surface treating agent (manufactured by Nippon Parkerizing Co., Ltd.
Immerse in Parfos-1077) (treatment agent) for 120 seconds,
After lifting, pure water was sprayed at room temperature for 30 seconds and washed with water. Then, it was immersed in the treatment solution shown in Table 2 for 30 seconds, pulled up, sprayed with pure water at room temperature for 30 seconds, washed with water, and then washed at 80 ° C.
For 180 seconds. The steel sheet thus surface-treated was used in Comparative Examples shown in Table 2.

Comparative Example 3 A cold-rolled steel sheet (0.
Spray Fine Cleaner-L4460 (A agent: 20 g / L, B agent: 12 g / L) (Nippon Parkerizing Co., Ltd., alkaline degreasing agent) at 43 ° C for 120 seconds using 8 x 300 x 100 mm size II). -Degreased, then sprayed with pure water at room temperature for 30 seconds and washed with water. Then, Preparen ZN (1.0 g / L) (Titanium Colloid II surface conditioner, manufactured by Nippon Parkerizing Co., Ltd.) was sprayed at room temperature for 30 seconds. This cold-rolled steel sheet was heated to 43 ° C using an iron phosphate surface treating agent (manufactured by Nippon Parkerizing Co., Ltd.
Galphos-1077) (treatment agent) for 120 seconds,
After raising, the pure water was spray-washed at room temperature for 30 seconds. Then, it was dried at 80 ° C. for 180 seconds. The steel sheet thus surface-treated was used in Comparative Examples shown in Table 2. [Comparative Example 4] Fine cleaner-L4460 (agent A: 20 g / L, agent B: 12 g / L) was used as a metal material by using a galvannealed steel sheet (GA, 0.8 x 300 x 100 mm size II) -12% at 43 ° C with an alkaline degreasing agent from Calising
It was spray-degreased for 0 second, and then pure water was sprayed at room temperature for 30 seconds and washed with water. Then, Preparen ZN (1.0 g / L) (Titanium Colloid II surface conditioner, manufactured by Nippon Parkerizing Co., Ltd.) was sprayed at room temperature for 30 seconds. This cold rolled steel sheet is
Immersed in a zinc phosphate surface treatment agent (Palbond-L3020, manufactured by Nippon Parkerizing Co., Ltd.) (treatment agent) heated to 120 ° C for 120 seconds, lifted, sprayed with pure water at room temperature for 30 seconds, and washed with water did. Then, it was dried at 80 ° C. for 180 seconds. The steel sheet thus surface-treated was used in Comparative Examples shown in Table 2.

[0075]

[Table 2]

As is clear from the results shown in Table 2, the coating films obtained by Examples 1 to 12 using the coating method of the present invention have good adhesion and corrosion resistance. On the other hand, Comparative Example 1 using a coating method outside the scope of the present invention
It can be seen that Nos. 4 to 4 are inferior in adhesion and corrosion resistance.

[0077]

According to the coating method of the present invention, a powder coating film having adhesion and corrosion resistance can be formed, and the characteristics of the powder coating material and the powder coating method are environmental friendliness and resource saving. Can be maximized.

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Claims (1)

[Claims] 1. The method according to claim 1, wherein the metal material having a surface treated with a phosphating solution contains one or more polymerized units represented by the following general formula (I) at an average degree of polymerization of 2 to 50. Component consisting of a phenolic compound derivative: [Wherein, X bonded to the benzene ring is a hydrogen atom, a hydroxyl group, a C1-C5 alkyl group, a C1-C5
A C5 hydroxyalkyl group, a C6-C12 aryl group, a benzyl group, a benzal group, an unsaturated hydrocarbon group condensed with the benzene ring to form a naphthalene ring, or a group of the following formula (II): Wherein R1 and R2 in the formula (II) each independently represent a hydrogen atom, a hydroxyl group, a C1-C5 alkyl group or a C1-C10 hydroxyalkyl group, and each of the formulas (I) and (II) In the formula, Y1 and Y2 bonded to the benzene ring are each independently one of Z groups represented by the following formula (III) or (IV): And R3, R4, R in the formulas (III) and (IV)
5, R6 and R7 each independently represent a hydrogen atom, a C1 to C10 alkyl group or a C1 to C10 hydroxyalkyl group, and each of X, Y1 and Y2 bonded to the benzene ring of the plurality of polymerized units. May be the same as each of X, Y1 and Y2 bonded to another benzene ring, or may be different from each other, and the number of substitutions of the Z group in the benzene ring of the plurality of polymerized units may be The average value is between 0.2 and 1.0. ], Drying after that, followed by powder coating.