JPH0940891A - Resin composition for powder coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition by blending a thermosetting or a thermoplastic resin with a specific charge controlling agent in a prescribed ratio, excellent in coating efficiency, uniformity of film thickness during electrostatic coating, sense of beauty, resistance to change in quality during melt blending, useful for electrostatic coating of various metals, concrete, etc. SOLUTION: This resin composition for a powder coating material is obtained by blending (A) a thermosetting or a thermoplastic resin with (B) a charge controlling agent comprising a polymer containing two or more cationic functional groups in the molecule [e.g. a graft polymer obtained by grafting a chain of a skeleton of the formula (R<1> is a 1-18C hydrocarbon group; R<2> and R<3> are each H, a 1-8C hydrocarbon group or R<2> and R<3> are bonded to form an aromatic ring; R<4> is a 1-12C alkylene which may contain an ether bond in the group; X<-> is an anion; (m) is 2-100) onto a polystyrene-based main chain or a mixture of the graft polymer and a homopolymer of the formula] in the ratio of the component A:B of 100:(0.1-20) by weight.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resin for powder coatings. More specifically, it relates to a resin for powder coating which is excellent in uniform coating property and coating efficiency.

[0002]

2. Description of the Related Art In recent years, with increasing interest in environmental problems, regulations on organic solvents having a large effect on the environment have been increasing. This trend is similar in the field of paints, and powder paints are positioned as a promising candidate as solvent-free paints. In addition to the characteristics of powder coating, such as resource saving type, good working environment, excellent coating strength, and easy automation of coating equipment, it is possible to form thick film with one coat because no solvent is used. Therefore, there is an advantage that the effect of cost reduction is great such that the uncoated portion of the paint can be used.

[0003]

However, powder coating is
There are drawbacks such as low coating efficiency and difficulty in forming a uniform coating on complicated shapes; some coatings are difficult to apply by the triboelectrification method. In particular, the low coating efficiency results in an increase in the amount of paint used, leading to an increase in cost. Further, if the coating film becomes non-uniform, it causes a serious problem in appearance. These problems are due to the fact that the paint is not appropriately charged, and as an attempt to control the charge amount of the paint, a method of using a polymer obtained by coexisting a quinoneimine dye as a charge control agent (for example, Japanese Patent Publication No. 7-
No. 43547), a method using a quaternary ammonium salt compound as a charge control agent (for example, JP-A-2-212).
No. 563) has been proposed.

However, since quinone imine dyes are colored, it is difficult to use them for powder coatings, and since they are complex mixtures, there is a problem that their properties are not constant, and that quaternary ammonium salt compounds have a moisture content. Many of them are highly dependent and have a small absolute amount of electrification, and their heat resistance is low, making it difficult to obtain stable quality by separating them in the paint kneading process;
Since the dispersibility in the powder coating resin is low, there is a problem that the powder coating spreads the charge distribution among the powder coating particles.

[0005]

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of extensive studies for the purpose of solving the above-mentioned problems in controlling the charge amount of the powder coating material. That is, the present invention comprises a thermosetting resin and / or a thermoplastic resin (A) and a charge control agent (B) composed of a polymer having two or more cationic functional groups in the molecule,
(A) :( B) weight ratio is 100: (0.1-20), It is a resin composition for powder coatings characterized by the above-mentioned.

In the present invention, the thermosetting resin used as (A) may be an epoxy resin, an epoxy-polyester hybrid resin, a combination of a polyester resin and a curing agent such as blocked isocyanate, an acrylic resin and a dibasic acid, or the like. A combination with a curing agent and the like can be mentioned.
Examples of the thermoplastic resin include vinyl chloride resin, polyamide resin, polyester resin and polyolefin resin. Two or more of these may be used in combination.

The graft polymer (C1) constituting (B) in the present invention has a graft chain represented by the following general formula (1) introduced into the functional group portion of the styrene resin (F) having a functional group. It is a thing. Therefore, the polystyrene-based main chain referred to in the present invention is obtained by removing the functional group portion of the styrene-based resin (F) having a functional group.

[0008]

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[Wherein R ¹ is a C _{1 to} C ₁₈ hydrocarbon group,
R ² and R ³ are each independently hydrogen or a C _{1 to} C ₈ hydrocarbon group (provided that R ² and R ³ are mutually connected to form an aromatic ring), R ⁴ the ether bond contain an C ₁ may be -C _{1 2} alkylene groups in the radical, X ^-
Represents an anion, and m represents an integer of 2 to 100. ]

As the styrene resin (F) having a functional group, a styrene resin (F1) having a halomethyl group,
Examples thereof include a styrene resin (F2) having an amino group.

Examples of (F1) include those obtained by copolymerizing styrene, a halomethylated styrene monomer and, if necessary, another monomer. Examples of (F2) include those obtained by copolymerizing styrene, an amino group-containing monomer and, if necessary, another monomer. Of these, preferred is (F1). In the (F1), examples of the halomethylated styrene monomer include chloromethylstyrene and bromomethylstyrene. Preferred among these is chloromethylstyrene.

In (F2), as the amino group-containing monomer, amino group-containing styrene (1-styrylmethylimidazole, etc.), amino group-containing (meth) acrylate {dimethylaminoethyl (meth) acrylate, 1-
[2- (meth) acryloyloxyethyl] imidazole)}, amino group-containing (meth) acrylamide {dimethylaminopropyl (meth) acrylamide, 1-
(Meth) acryloyl imidazole and the like}. Among these, preferred are amino group-containing (meth) acrylates and amino group-containing (meth) acrylamides.

In the above-mentioned (F1) or (F2), other monomers used as a copolymerization component as required include styrene substitution products, (meth) acryl-based monomers and other vinyl-based monomers.

Examples of the substituted styrene include alkyl-substituted styrenes (α-methylstyrene, p-methylstyrene,
p-cumyl styrene, etc.), halogen-substituted styrene [(poly) chlorostyrene, (poly) bromostyrene, etc.], acetoxystyrene, hydroxystyrene and the like.

As the (meth) acrylic monomer,
(Meth) acrylate {C ₁ -C ₁₈ alkyl (meth)
Acrylate [(methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc.], hydroxyl group-containing (meth) acrylate [hydroxyethyl (meth) acrylate, etc.]}, (meth) acrylamide [(meth) acrylamide Etc.], nitrile group-containing (meth) acrylic monomers [(meth) acrylonitrile, etc.], and the like.

Other vinyl monomers include vinyl ester (vinyl acetate, etc.), aliphatic vinyl hydrocarbon (butadiene, isoprene, etc.), halogenated olefin (vinyl chloride, vinyl bromide, etc.), unsaturated mono- or polycarboxylic acid. Acid [(meth) acrylic acid, crotonic acid,
Maleic acid, itaconic acid, cinnamic acid, etc.], and their anhydrides (maleic anhydride, etc.) and the like.

The copolymerization ratio of styrene with a halomethylated styrene monomer or an amino group-containing monomer and optionally other monomer is based on a molar ratio, usually 50 to 99.5% of styrene, halomethylated styrene monomer or amino. Group-containing monomer is 0.5 to 30%, other monomer is 0 to 40%, preferably styrene is 60 to
99%, halomethylated styrene monomer or amino group-containing monomer 1 to 20%, other monomer 0 to 30%
It is.

The styrenic resin (F) having a functional group does not necessarily have to be copolymerized with a monomer having a functional group from the beginning. That is, the desired functional group may be introduced into the previously obtained styrene resin having no functional group. For example, a styrene-based resin may be halomethylated by a known method to obtain a styrene-based resin having a halomethyl group (F1) having substantially the same structure.

In the above general formula (1), C _{1 to} C of R ¹
The hydrocarbon group of ₁₈ includes an alkyl group (methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, n-hexyl group, cyclohexyl group Xyl group, n-octyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, etc.), alkenyl group (undecenyl group, dodecenyl group,
Tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, etc.), alkylphenyl group (pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, etc. ) And the like. Among these, preferred are C _{11 to} C ₁₇ alkyl groups and alkenyl groups. Particularly preferred are C ₁₁ -C ₁₇ alkyl groups.

The hydrogen of R ² and R ³ or the hydrocarbon group of C _{1 to} C ₈ is hydrogen, alkyl group (methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, etc.), aryl group. (A phenyl group etc.) and an aralkyl group (A benzyl group etc.) etc. are mentioned. Examples of the aromatic ring in which R ² and R ³ are connected to each other include a benzo group. Among these, preferred are hydrogen, methyl group, ethyl group and benzo group.

Examples of the C ₁ -C ₁₂ alkylene group of R ⁴ include methylene group, ethylene group, trimethylene group, tetramethylene group, hexamethylene group, octamethylene group and dodecamethylene group. Examples of the alkylene group C ₁ -C ₁₂ containing an ether bond of ^{_{R 4, -CH 2 CH 2 OCH}} 2 CH 2 - -CH 2 CH 2 OCH 2 OCH 2 CH 2 - -CH 2 CH 2 OCH 2 CH ₂ OCH ₂ CH ₂ — and the like. Among these, preferred are an ethylene group, trimethylene group, tetramethylene group, hexamethylene group, dodecamethylene _{group, -CH 2 CH 2 OCH 2 CH} 2
- and _{-CH 2 CH 2 OCH 2 OCH 2} CH 2 - and it is,
More preferred are trimethylene group, tetramethylene group, hexamethylene group, dodecamethylene group and -CH.
₂ CH ₂ OCH ₂ CH ₂ —.

As the anion of X, halogen ion (chlorine ion, bromine ion, iodine ion, etc.), sulfate ion, nitrate ion, phosphate ion, sulfonate ion (p
-Toluenesulfonate ion, methylsulfonate ion, hydroxynaphthosulfonate ion, etc.), borate ion (tetrafluoroborate ion, tetraphenylborate ion, metaborate ion, metaborate-glycerin complex ion, etc.), oxo acid Examples thereof include ions (molybdate ion, tungstate ion, etc.) and carboxylate ion (acetate ion, etc.). Of these, preferred are halogen ions, sulfonate ions,
A borate ion and an oxo acid ion.

The molecular weight of the graft polymer (C1) is not particularly limited, but the number average degree of polymerization of the polystyrene main chain, that is, the number average degree of polymerization of the styrene resin (F) is usually 5 to 500, It is preferably 10 to 400,
The number average degree of polymerization m of the graft chain is 2 to 100, preferably 4 to 80. If the number average degree of polymerization of the styrene resin (F) is lower than 5 or higher than 500, the dispersibility in the powder coating resin is deteriorated. Further, when the number average degree of polymerization of the graft chain is lower than 2, the required charging performance is not exhibited, and when it is higher than 100, the dispersibility in the powder coating resin is lowered. The graft polymer (C1) does not need to have a structure in which only one end of all graft chains is bonded to the polystyrene main chain, and both ends of some graft chains are bonded to the styrene polymer. You may take the structure.

The charge control agent (B) in the present invention comprises the graft polymer (C1) or a mixture of the (C1) and a polymer (C2) represented by the following general formula (2).

[0025]

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[In the formula, R ^{1 to} R ⁴ and X ⁻ are the same as in the general formula (1), and n represents an integer of 2 to 100. ]

This polymer (C2) is a graft polymer (C
A homopolymer obtained by homopolymerizing a part of the graft chain of 1) without binding to the main chain. The number average degree of polymerization n of the polymer (C2) is usually 2 to 100, preferably 10 to 80. If the number average degree of polymerization of the polymer (C2) is less than 2, the appearance of the coating film deteriorates due to migration of the polymer (C2) to the surface, and
If it exceeds 00, the dispersibility in powder coating is lowered. The composition ratio of each component in the charge control agent is such that the graft polymer (C
In terms of the weight ratio of the graft chain constituting 1) and the weight ratio of the polymer (C2), the former is usually 25 to 100%, preferably 40 to 80, and the homopolymer is usually 0 to 75%, preferably 20. -60. When the weight ratio of the graft chains constituting the graft polymer (C1) is less than 25%, the dispersibility in the powder coating resin is lowered.

Specific examples of the charge control agent (B) in the present invention are shown by the following combinations of the styrene resin (F) and the graft chain.

Styrene resin (F): Styrene / chloromethylstyrene copolymer Graft chain: Graft chain represented by the following general formula (3)

[0030]

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Styrenic resin (F): Styrene / butyl acrylate / chloromethylstyrene copolymer Graft chain: Graft chain represented by the following general formula (4)

[0032]

[Chemical 6]

Styrene resin (F): Styrene / butyl acrylate / chloromethylstyrene copolymer Graft chain: Graft chain represented by the following general formula (5)

[0034]

[Chemical 7]

Styrene resin (F): Styrene / butyl acrylate / dimethylaminoethyl methacrylate copolymer Graft chain: Graft chain represented by the following general formula (6)

[0036]

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Styrenic resin (F): Styrene / butyl methacrylate / chloromethylstyrene copolymer Graft chain: Graft chain represented by the following general formula (7)

[0038]

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Styrenic resin (F): Styrene / butyl methacrylate / chloromethylstyrene copolymer Graft chain: Graft chain represented by the following general formula (8)

[0040]

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Styrenic resin (F): Styrene / butadiene acryloyloxyethyl imidazole copolymer Graft chain: Graft chain represented by the following general formula (9)

[0042]

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Usually, when the graft polymer (C1) is produced, (C2) is by-produced to form a mixture of (C1) and (C2). As an example of the production method of (C1), a method of reacting a styrene resin (F) having a functional group with an imidazole and a dihalide can be mentioned. Further, the graft polymer (C1) can be isolated by purifying and removing (C2) from the reaction product.

The above-mentioned imidazoles include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-phenylimidazole, 2-stearylimidazole, 2,4-dimethylimidazole, 4,5-dimethylimidazole, Examples thereof include benzimidazole and 2-methylbenzimidazole.

Examples of the dihalide include alkylene dihalides (ethylene dichloride, ethylene dibromide, 1,3-dibromopropane, 1,4-dichlorobutane, 1,4-dibromobutane, 1,6-dibromohexane, 1,8 -Dibromooctane), aralkylene dihalides (xylylene dichloride, etc.), alkylene dihalides containing an ether bond in the group (β, β'-dichloroethyl ether, β, β'-dichloroethylformal, etc.), etc. To be

With respect to the reaction molar ratio, when (F1) is used as the styrene resin (F), the number of halomethyl groups in (F1) is X1, the number of imidazoles is Y, and the number of dihalides is Z. Then, usually 2 ≦ Z / X1 ≦ 100, −0.5 ≦ (Y−Z) / X1 ≦
3, preferably 2 ≦ Z / X1 ≦ 70, 0 ≦ (Y−Z) / X1 ≦ 2, and more preferably 3 ≦ Z / X1 ≦ 50, 0 ≦ (Y−Z) / X1 ≦ 2. Is. When Z / X1 is less than 2, the degree of polymerization of the graft chain becomes small, and a sufficient amount of quaternary ammonium base cannot be introduced. When it exceeds 100, it is difficult to complete the reaction. Further, if (YZ) / X1 is less than -0.5 or exceeds 3, the grafting ratio is lowered and a large amount of ungrafted styrene polymer is by-produced, which is not preferable.

When (F2) is used as the styrenic resin (F), assuming that the number of moles of the amino group of (F2) is X2, 2≤Y / X2≤100, -0.5≤ (Z- Y) / X2 ≦
3, preferably 2 ≦ Y / X2 ≦ 70, 0 ≦ (Z−Y) / X2 ≦ 2, and more preferably 3 ≦ Y / X2 ≦ 50, 0 ≦ (Z−Y) / X2 ≦ 2. Is. When Y / X2 is less than 2, the degree of polymerization of the graft chain is small, and a sufficient amount of quaternary ammonium salt cannot be introduced. When Y / X2 exceeds 100, it is difficult to complete the reaction. When (Z-Y) / X2 is less than -0.5 and exceeds 3, the grafting ratio is lowered and a large amount of ungrafted homopolymer is produced as a by-product.

If necessary, a monohalide or N-substituted imidazole may be used in combination for the purpose of blocking the ends of the graft polymer.

Examples of monohalides include methyl chloride, methyl iodide, ethyl bromide, butyl bromide, butyl chloride, benzyl chloride and benzyl bromide.

Examples of the N-substituted imidazole include 1-methylimidazole, 1-ethylimidazole and 1-benzylimidazole.

The molar ratio of the monohalide or N-substituted imidazole to the other reaction components is such that the number of moles of the functional group of the styrenic polymer (a) having a functional group is X and the number of moles of the imidazoles (b) is Y. , The number of moles of dihalide (c) is Z,
When the number of moles of monohalide or N-substituted imidazole is W, 0 ≦ W ≦ 1.2 (2Y-2Z-X) is usually satisfied.

In the method for producing the polymer (C1), an alkali metal and an ammonium salt of an anion other than halogen may be used in combination for the purpose of changing the anion of X to an anion other than the halogen exemplified above.

Any reaction solvent that is inert to imidazoles and dihalides can be used. Examples of the solvent include aromatic solvents such as benzene, toluene and xylene; ketone solvents such as acetone and methyl ethyl ketone; aprotic polar solvents such as dimethylformamide, dimethylacetamide and dimethylsulfoxide; and water, methanol, and the like. A mixed solvent with an alcohol solvent such as ethanol or isopropanol can be used. Of these, aprotic polar solvents are preferred because they can react in a homogeneous system, and dimethylformamide is particularly preferred.

It is preferable to use an alkali in combination for the purpose of neutralizing hydrogen halide generated by the reaction. Examples of the alkali include sodium hydroxide, potassium hydroxide, sodium carbonate and the like.

The reaction method is preferably such that dihalide is added dropwise to a solution containing the styrene resin (F), imidazoles and alkali, but it is also possible to charge them at the same time, and the imidazole and dihalide are first reacted to give styrene. The system resin (F) may be added and reacted. After completion of the reaction, the by-produced inorganic salt is removed by filtration or centrifugation, and then the solvent is distilled off to obtain a mixture of the graft polymer (C1) and the polymer (C2).

Then, if necessary, extraction with water or reprecipitation in water gives a homopolymer of graft chains (C2).
The graft polymer (C1) simple substance is obtained by removing. When a water-soluble solvent such as dimethylformamide is used as the reaction solvent, the inorganic salt, the solvent and the homopolymer are simultaneously removed by pouring the reaction mixture into water,
It is also possible to obtain a powdery graft polymer (C1).
The reaction temperature is usually 30 to 200 ° C., preferably 60 to 18
0 ° C. If the temperature is lower than 30 ° C, the reaction rate is slow,
If it exceeds, side reactions are likely to occur, which is not preferable. The reaction time varies depending on the reaction temperature, but is usually about 2 to 20 hours.

The powder coating resin composition of the present invention contains a thermosetting resin and / or a thermoplastic resin (A) and a charge control agent (B) as essential components, and when it is used as a powder coating composition. From the standpoint of charging property, the weight ratio of (A) :( B) is usually 100: (0.1-20), preferably 100: (0.
1 to 5). When the ratio of (B) is less than 0.1, the charge control performance is not exhibited, and when it exceeds 20, the physical properties such as coating film strength are deteriorated when used as a powder coating material.

The resin composition of the present invention can be easily made into a powder coating material by a known method. For example, 5 to 30 parts by weight of a curing agent and 20 to 40 parts by weight of a pigment such as titanium oxide are melt-mixed with 100 parts by weight of a resin composition, cooled, and then pulverized by a pulverizer to obtain powder. Use as paint. In addition, metal powder, a filler, a leveling agent, a plasticizer, a stabilizer and the like can be contained as required. The powder coating material thus obtained is applied to a metal coating object using an electrostatic coating machine,
Usually, baking is performed at 120 to 200 ° C.

The powder coating material obtained from the resin composition of the present invention can be applied to iron materials, cast irons, steel sheets, stainless steels, aluminum materials, and aluminum die-casts by various electrostatic coating machines such as a corona application method, a friction charging method or a hybrid method. It can be applied to a wide range of substrates such as sintered metal, glass, concrete, and special resins. Further, it is also possible to apply a primer treatment or other undercoat treatment to these base materials for coating.

[0060]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. In the following:
Parts are parts by weight. The molecular weight measurement by GPC was performed under the following conditions. Equipment: Waters column: Ultrastyra gel linear 2 Measurement temperature: 25 ° C Sample solution: 0.5 wt% THF solution Injection volume: 200 μl Detector: Refractive index detector Standard polystyrene is used for the molecular weight calibration curve. Created.

[Synthesis of Polymer (B)] Production Example 1 794 parts of styrene, 160 parts of butyl acrylate and 46 parts of chloromethylstyrene were polymerized with 30 parts of azobisisobutyronitrile as an initiator in a toluene boiling point. Then
Then, the solvent was removed, and a styrene-based resin (F having a number average molecular weight of 6000 and a weight average molecular weight of 17,000) having halomethyl (F
1-1) was obtained. 128 parts of the (F1-1), 125 parts of heptadecylbenzimidazole, 68 parts of 1,4-dibromobutane and 18 parts of sodium carbonate were added to dimethylformamide (DMF) at 80 ° C. for 2 hours and further under reflux under 4 conditions. Reacted for hours. Then, 5 parts of benzyl chloride was added and the mixture was refluxed for 4 hours. After completion of the reaction, the reaction product was put into an aqueous solution in which 205 parts of p-toluenesulfonic acid was dissolved in 2000 parts of water while stirring with a homomixer. The precipitate is washed with water, filtered and dried to give the graft polymer (B-1)
I got This is designated as the charge control agent (B-1) of the present invention.

Production Example 2 453 parts of (F1-1) obtained in Production Example 1, 380 parts of heptadecylimidazole, 241 parts of 1,4-dibromobutane and 66 parts of sodium carbonate were added in DMF at 80 ° C. for 2 hours. Then, the mixture was further reacted under reflux for 4 hours. Then, 18 parts of benzyl chloride was added and the mixture was refluxed for 4 hours. After the reaction,
The reaction product was put into an aqueous solution in which 320 parts of sodium neville winterate was dissolved in 2000 parts of water while stirring with a homomixer. The precipitate was washed with water, filtered and dried to obtain a graft polymer (B-2). This is designated as the charge control agent (B-2) of the present invention.

Example 1 Acrylic resin ["Findick A-223S",
Made by Dainippon Ink and Chemicals, Inc.] 100 parts, dodecane 2
20 parts of acid, 1 part of the charge control agent (B-1) of Production Example 1, leveling agent [“Modaflow”, manufactured by Monsanto Co., Ltd.] 1
Part, benzoin 1 part and epoxy resin [“Epicoat 1001”, Shell Co., Ltd.] 2 parts were dry blended and then melt-kneaded with a KRC kneader (Kurimoto Tekko Co., Ltd.), and the obtained kneaded product was a SKM-10 type sample. The powder was crushed with a mill [manufactured by Kyoritsu Riko Co., Ltd.], and an ultrasonic hand shifter (manufactured by Tsutsui Rika Kikai) was used to obtain powder of 200 mesh.

COMPARATIVE EXAMPLE 1 The composition of Example 1 containing no charge control agent (B-1) was prepared in the same manner as a comparative sample.

Example 2 (B-1) having the composition of Example 1 was obtained in Production Example 2 (B-
A powder was prepared in the same manner except that it was replaced with 2).

Example 3 Polyester resin ["Findick M-802
0 ", manufactured by Dainippon Ink and Chemicals, Inc.] 100 parts, blocked isocyanate 15 parts, charge control agent of Production Example 1 (B
-1) 1 part, "Modaflow" 1 part, benzoin 1 part,
After dry blending 2 parts of "Epicoat 1001", a powder (passing through 200 mesh) was obtained in the same manner as in Example 1.

Comparative Example 2 A powder was prepared in the same manner by using the composition of Example 3 containing no polymer (B-1) as a comparative sample.

Example 4 A powder was prepared in the same manner as in Example 3, except that (B-1) was replaced with (B-2) of Production Example 2.

Comparative Example 3 A powder was prepared in the same manner as in Example 1 except that the charge control agent (B-1) was replaced with dimyristyldimethylammonium 1-hydroxynaphthalene-4-sulfonate in the same amount. , As a comparative sample.

Comparative Example 4 A powder was prepared in the same manner as in Example 3 except that the charge control agent (B-1) was replaced with dimyristyldimethylammonium-1-hydroxynaphthalene-4-sulfonate in the same amount. Then, it was used as a comparative sample.

(Coating Comparison Test) Using each of the samples of Examples 1 to 4 and Comparative Examples 1 to 4, a coating comparison test by a corona application method was carried out under the following conditions. Table 1 shows the results.
Shown in Electrostatic powder coating machine: MPS1 (Matsugema) Applied voltage: -30KV Discharge rate: 100g / min Coating object: Zinc phosphate treated steel plate (0.6mm thickness x 200mm length x 100mm width) Coating object and coating gun Distance from tip: 20 cm Baking conditions: 170 ° C x 20 minutes (Examples 1, 2 and Comparative Examples 1 and 3) 180 ° C x 20 minutes (Examples 3 and 4, Comparative Examples 2 and 4)

[0072]

[Table 1] ----------------------- Example 1 Example 2 Example 3 Example 4- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Coating efficiency * 95% 94% 96% 97% Film thickness 60 to 65 μ 65 〜70μ 60〜65μ 55〜60μ Appearance Good Good Good Good Good ---------- Comparative Example 1 Comparison Example 2 Comparative Example 3 Comparative Example 4 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Coating efficiency * 70% 72% 80 % 83% Film thickness 60 to 85μ 55 to 80μ 60 to 75μ 65 to 80μ Appearance Yuzu skin Yuzu skin Yuzu skin Yuzu skin −−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−− *; Coating efficiency (%) = ( Chakuryou / discharge rate) × 100

(Measurement of Charge Amount) 24 parts of carrier powder for electrophotography "ASR-10" (manufactured by Nippon Iron Powder Co., Ltd.) was mixed with 1 part of these powder coatings, and a tumbler shaker mixer (100 revolutions x The toner was triboelectrically charged for 1 hour, and the charge amount was measured by a blow-off charge amount measuring device [manufactured by Toshiba Chemical Co.]. The results are shown in Table 2.

[0074]

[Table 2] -------------------------------------------- Band charge (μC / g) ---- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Friction charging time 1 minute 3 minutes 7 minutes 20 minutes 60 minutes ----- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 1 +2.8 +3.6 +4.2 +5.3 +7.5 Example 2 +2.7 +3.6 +4.3 +5.4 +7.6 Example 3 +2.6 +3.4 +4.1 +5.1 +7.2 Example 4 +2.5 +3.4 +4.0 +5.2 +7 . 2 -------------------------------------------- Comparative example 1 +0.2 +0.3 +0.6 +1 .4 +2.5 Comparative Example 2 +0.3 +0.4 +0.5 +1.2 +2.6 Ratio Example 3 +0.8 +1.4 +2.3 +3.2 +3.8 Comparative Example 4 +0.7 +1.3 +2.3 +3.3 +3.6 + -−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−

(Measurement of charge amount distribution) The charge amount distribution was measured by using a particle charge amount distribution measuring device [“EST-1” manufactured by Hosokawa Micron Co., Ltd.) for Examples 1 to 4 in which friction stirring was performed for 20 minutes. As shown in Table 2, all powder coatings had a sharp charge amount distribution, although there were differences in the charge amount. When the same measurement was performed on Comparative Examples 1 to 4, a wide charge distribution was confirmed.

[0076]

The powder coating material using the resin for powder coating material of the present invention has the following effects as compared with the conventional powder coating material. (1) Since powder having an appropriate charge amount can be obtained, it is possible to increase the coating efficiency with respect to the object to be coated, which is effective in cost reduction. (2) In order to obtain a powder with a sharp charge distribution,
A uniform and beautiful film thickness can be obtained by electrostatic coating. (3) The ionic functional group of the charge control agent (B) has a structure with high heat resistance [(benzo) imidazolium salt structure], and alteration does not occur in the melt-kneading in the coating step. From the above effects, the powder coating resin of the present invention is capable of both cost reduction and appearance improvement, and greatly expands the application of the powder coating, and is industrially extremely useful. Is.

Claims (2)

[Claims] 1. A thermosetting resin and / or a thermoplastic resin (A), and a charge control agent (B) comprising a polymer having two or more cationic functional groups in the molecule,
A resin composition for powder coatings, wherein the weight ratio of (A) :( B) is 100: (0.1-20). 2. A graft polymer (C1) having (B) a polystyrene-based main chain and a graft chain having a skeleton represented by the following general formula (1), or the graft polymer (C1). Polymer (C2) represented by the following general formula (2)
The composition of claim 1 which comprises a mixture of Embedded image [Wherein R ¹ is a C _{1 to} C ₁₈ hydrocarbon group, R ² and R ³
Are each independently hydrogen or a C _{1 to} C ₈ hydrocarbon group (provided that R ² and R ³ are mutually connected to form an aromatic ring), and R ⁴ is an ether in the group. may contain a coupling C ₁ -C _{1 2} alkylene group, X ^- is an anion, m represents an integer of 2 to 100. ] [Chemical 2] Wherein, R ¹ to R ⁴ and X ^- is the same as that General formula (1), n represents an integer of 2 to 100. ]