JP3481365B2 - Colored metallic pigment for powder coating and powder coating composition containing the pigment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored metallic pigment used for finishing powder metallic coating of automobiles, household appliances, toys and the like, a method for producing the same, and a powder coating material containing the pigment.

[0002]

2. Description of the Related Art Powder coatings are being widely used as low-pollution coatings that do not use organic solvents for finishing powder metallic coatings for automobiles, home appliances, toys and the like.

When a powder coating material containing a colored metallic pigment is used for finishing a powder metallic coating, it is difficult to arrange the metallic pigment parallel to the base material, and therefore, to give a metallic feeling to the powder. In addition to the problem that the amount of the metallic pigment in the paint needs to be greater than that of the solvent-based paint, there is also a problem that a coating film having a good appearance cannot be obtained. This is because the metallic pigment is likely to be exposed on the surface of the coating film, and even if a coloring pigment is added, the color of the metallic pigment is emphasized and it is difficult to obtain a vivid color. Further, the uneven distribution of the metallic pigment tends to occur when the paint is melted to form a film, and the uneven distribution of the metallic pigment tends to occur in the vicinity of the surface of the coating film, which is another reason why vivid colors cannot be obtained.

The metallic pigments conventionally developed for powder coatings are metallic pigments previously coated with a resin by a spray drying method or the like (for example, JP-A-51-137725).
Gazette, Japanese Patent Publication No. 57-35214, etc.). In the case of these metallic pigments, by coating the metallic pigment with a resin in advance, the adhesion efficiency in electrostatic powder coating is improved, but the above-mentioned appearance problem has not been solved.
Furthermore, the step of spray-drying the metallic pigment is accompanied by the risk of solvent ignition or dust explosion, and the resulting dry powder tends to agglomerate, causing defects such as spots when powder-coated. There is also.

A method in which a metallic pigment is sufficiently kneaded with a resin or a color pigment in advance by a melting method can be considered, but in the melting method, the metallic pigment is deformed in a kneading step or a particle size adjusting step of powder coating material such as pulverization. A coating film which is easy and has a very good appearance cannot be obtained.

[0006]

The main object of the present invention is to:
The present invention aims to solve the problem of the appearance of the coating film, which has been a drawback of metallic powder paints. Here, the appearance of the coating film refers to the color tone such as color vividness and metallic feeling, the presence or absence of defects such as spots and color unevenness, and the gloss of the coated surface.

[0007]

The colored metallic pigment for powder coatings of the present invention is obtained by synthesizing the surface of a colored metallic pigment, which is obtained by adhering a colored pigment on the surface of a base metallic pigment, from a monomer by in-situ polymerization. It is characterized by being coated with a polymer and having a residual solvent amount of 5% by weight or less.

According to the present invention, the color pigment can be attached to the individual base metallic pigment particles, thereby preventing the saturation of the coating film due to the uneven distribution of the metallic pigment. The color pigment may be only partially attached to the surface of the individual metallic pigment particles, but it is preferably uniformly attached to the entire surface of the individual metallic pigment particles.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The residual solvent amount of the colored metallic pigment for powder coating of the present invention is 5% by weight or less, more preferably 2% by weight or less.
It is desirable that the content be less than or equal to weight%. The residual solvent referred to here is pulverized base metallic pigment or i of polymerizable monomer.
Hydrocarbon-based solvents used during n-situ polymerization, alcohol-based, ester-based, and ketone-based solvents used during dispersion of color pigments are included. If the amount of residual solvent exceeds 5% by weight, the colored metallic pigment forms agglomerates when the colored metallic pigment and the coating resin powder are mixed, and thus it becomes impossible to mix them uniformly, and the powder coating is piped. There is also a problem in that the flow becomes poor when it is conveyed through such as, and it becomes easy to become clogged.

Metal flakes such as aluminum, zinc, copper, bronze, nickel, titanium, and stainless are suitable as the metallic pigment that is the base of the colored metallic pigment for powder coating of the present invention. Above all, it has excellent metallic luster,
Aluminum flake is particularly preferable because it is inexpensive and easy to handle because of its small specific gravity. The metallic pigment has a thickness of 0.1 to 5 μm and an average particle size of 5 to 100 μm, and the shape factor obtained by dividing the average particle size by the thickness is preferably in the range of about 5 to 100.

The color pigment to be attached to the surface of the metallic pigment may be organic or inorganic, and examples of color pigments that can be specifically used include the following types: phthalocyanine, halogenated phthalocyanine, quinacridone, diamine. Ketopyrrolopyrrole, isoindolinone, azomethine metal complex, indanthrone, perylene,
Perinone, anthraquinone, dioxazine, benzimidazolone, condensed azo, triphenylmethanequinophthalone, anthrapyrimidine, titanium oxide, iron oxide, carbon black.

Particularly preferred coloring pigments in terms of adhesion and coloring power are phthalocyanine blue, phthalocyanine green, quinacridone maroon, quinacridone gold, diketopyrrolopyrrole, isoindolinone orange, dioxazine violet, perylene maroon azomethine copper complex, Examples include anthrapyrimidine yellow, ultrafine particle titanium oxide, transparent iron oxide, and carbon black.

The color pigment has a primary particle diameter of 0.01.
˜1 μm, preferably 0.02 to 0.1 μm is preferably used.

[0014] surface area 1 m ² per quantities metallic pigment of the colored pigment to adhere to the surface of the substrate metallic pigment 0.
A range of 01 to 0.5 g, more preferably 0.03 to 0.3 g is suitable. If the adhered amount is too small, the coloring cannot be sufficiently performed, and if the adhered amount is too large, the color pigment tends to come off. It is preferable to adjust the addition amount of the color pigment so that a color pigment layer having a thickness of one particle of the color pigment is formed on the entire surface of each metallic pigment particle. It is ideal to adjust the addition amount of the color pigment so that the thickness of the color pigment layer is one particle of the color pigment. By doing so, it is possible to efficiently and vividly color each metallic pigment. In addition, it is easy to fix the color pigment on the surface of the metallic pigment, and it is possible to minimize the loss of the color pigment during the manufacturing process of the powder coating material.

In the colored metallic pigment for powder coating of the present invention, the coloring pigment has a coating layer of a monobasic aromatic carboxylic acid or a coating layer of a monobasic aromatic carboxylic acid and an aluminum or titanium chelate compound. Is desirable. The monobasic aromatic carboxylic acid is effective in efficiently adhering the color pigment to the metallic pigment. Also,
The aluminum or titanium chelate compound improves the dispersibility of the color pigment and is effective in uniformly and finely adhering the color pigment to the metallic pigment.

Examples of the monobasic aromatic carboxylic acid include the following compounds: benzoic acid, vinyl benzoate, salicylic acid, anthranilic acid, m-aminobenzoic acid, p-aminobenzoic acid and 3-amino-4-. Methylbenzoic acid, p-aminosalicylic acid, 1-naphthoic acid, 2-naphthoic acid, naphthenic acid, 3-
Amino-2-naphthoic acid, cinnamic acid, aminocinnamic acid.

Among these, benzoic acid, aminobenzoic acid (anthranilic acid, etc.), aminohydroxybenzoic acid (aminosalicylic acid, etc.), naphthoic acid (2-naphthoic acid, etc.),
Aminonaphthoic acid (3-amino-2-naphthoic acid and the like), cinnamic acid, and aminocinnamic acid are preferable because they are particularly excellent in improving the adhesion between the metallic pigment and the coloring pigment.

The amount of the monobasic aromatic carboxylic acid added is suitably 0.2 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, based on 100 parts by weight of the color pigment. If the added amount is too small, it is difficult to attach the coloring pigment to the metallic pigment very efficiently. Further, if the addition amount is too large, even if the surface of the colored metallic pigment is coated with a polymer, the colored pigment cannot be sufficiently fixed to the metallic pigment. The basic aromatic carboxylic acid causes problems such as deterioration of weather resistance of the powder coating film and the like.

Examples of the aluminum or titanium chelate compound include the following compounds: dialkoxy aluminum alkyl acetoacetate, aluminum trialkyl acetoacetate, aluminum triacetyl acetonate, aluminum acetyl acetonate bisethyl acetoacetate, aluminum isopropoxide. Alkyl phosphate alkyl acetoacetate, titanium tetraacetyl acetonate, dialkoxy titanium bisacetyl acetonate, dialkoxy bistriethanolamine titanate.

The amount of aluminum or titanium chelate compound added is 0.1 to 50 parts by weight per 100 parts by weight of the pigment.
It is suitable to use parts by weight, more preferably 0.5 to 20 parts by weight. If the addition amount is too small, the colored metallic pigment cannot be uniformly and finely adhered to the metallic pigment, and it is difficult to obtain a vivid color. Also, if the addition amount is too large, even if the surface of the colored metallic pigment is coated with a polymer, the colored pigment cannot be sufficiently fixed to the metallic pigment, and an excessive chelate is added when the colored metallic pigment is mixed in a paint or a coating film. The compound causes inconveniences such as causing problems such as deterioration of weather resistance of the powder coating film.

The surface of the color pigment attached to the surface of the metallic pigment is coated with a polymer synthesized from a polymerizable monomer by in-situ polymerization. Where in-situ
Polymerization means polymerizing by polymerizing a polymerizable monomer in the process of producing a colored metallic pigment.
The polymer plays a role of fixing into the metallic pigment by adhering to the gap between the coloring pigment and the surface of the metallic pigment, and can improve the adhesion of the coloring pigment to the metallic pigment.

The polymers used to coat the surface of colored metallic pigments are synthesized, for example, from the following polymerizable monomers: acrylic acid, methacrylic acid, methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate. , Lauryl acrylate, stearyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxybutyl acrylate, acrylic acid
2-methoxyethyl, 2-diethylaminoethyl acrylate, butyl methacrylate, octyl methacrylate, 1,4-
Butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate,
Neopentyl glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate,
Pentaerythritol triacrylate, trisacryloxyethyl phosphate, ditrimethylolpropane tetraacrylate, styrene, α-methylstyrene,
Vinyltoluene, divinylbenzene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, maleic acid, crotonic acid, itaconic acid, polybutadiene, linseed oil, soybean oil, epoxidized soybean oil, epoxidized polybutadiene, cyclohexene vinyl monooxide, Divinylbenzene monooxide.

The coating amount of the polymer is 0.5 to 100 with respect to 100 parts by weight of the colored metallic pigment to which the colored pigment is attached.
By weight, more preferably from 3 to 20 parts by weight is suitable.
If the coating amount is too small, the color pigment cannot be sufficiently fixed to the metallic pigment, and if the coating amount is too large, the metallic pigment agglomerates to cause problems such as lowering of gloss on the coated surface and occurrence of spots.

By coating the colored metallic pigment with a polymer, an electrically insulating layer is formed on the surface of the colored metallic pigment, which prevents current leakage through the metallic pigment during electrostatic powder coating, and prevents the adhesion. Efficiency is improved. Withstand voltage of colored metallic pigment for powder coating is 80k
It is preferably V or more. When the withstand voltage is less than 80 kV, the colored metallic pigment cannot be sufficiently charged when coated with an electrostatic powder coating machine, and the amount of the colored metallic pigment adhering to the substrate is reduced as a result. The metallic feeling of the coating film becomes poor. The withstand voltage of 80 kV or more is usually achieved by setting the coating amount of the polymer to 3 parts by weight or more based on 100 parts by weight of the colored metallic pigment to which the coloring pigment is attached. The amount may be 3 parts by weight or less depending on the type of color pigment and the type of polymerizable monomer.

The preferred method for producing the colored metallic pigment for powder coatings of the present invention is as follows. If necessary, in the presence of a monobasic aromatic carboxylic acid, or a monobasic aromatic carboxylic acid and an aluminum or titanium chelate compound, the color pigment is dispersed in a non-polar solvent to form a monobasic aromatic group on the surface of the color pigment. Forming a coating layer of a group carboxylic acid or a coating layer of a monobasic aromatic carboxylic acid and an aluminum or titanium chelate compound to produce a dispersion of a surface-treated color pigment, b. a step of adding and mixing a metallic pigment to the dispersion of the surface-treated color pigment of a, and depositing the surface-treated color pigment on the surface of the metallic pigment; c. The polymerizable monomer and the polymerization initiator are added to the metallic pigment to which the surface-treated color pigment of b is attached, and this is heated with stirring to synthesize a polymer from the polymerizable monomer.
Depositing the polymer on the surface of the colored metallic pigment; d. a step of solid-liquid separating the dispersion containing the colored metallic pigment to which the polymer of c is adhered into a paste by using a filtering device; e. and heating the paste-like colored metallic pigment of d) under reduced pressure while mixing to remove the solvent component.

If necessary, the color pigment is dispersed in a non-polar solvent in the presence of a monobasic aromatic carboxylic acid or in the presence of a monobasic aromatic carboxylic acid and a chelate compound to prepare a dispersion of the color pigment. After that, a metallic pigment is added to the dispersion to further disperse it. At this time, almost all of the coloring pigment adheres to the metallic pigment, and almost no pigment remains in the solvent. According to the present invention, almost all of the color pigments added in this adsorption step can be adsorbed, whereby a colored metallic pigment of stable quality can be produced. A preferable method for dispersing the color pigment is a dispersing method using a grinding medium such as a ball mill, a bead mill, a sand mill or the like. As a dispersion method after adding the metallic pigment, stirring with a stirrer or a disper is also suitable in addition to the above-described dispersion method using the grinding medium. In addition, it is also effective to add a metallic pigment, solid-liquid separate the mixture into a paste, and knead the mixture with a kneader mixer or the like.

As the non-polar solvent in which the color pigment is dispersed, an aliphatic hydrocarbon or aromatic hydrocarbon having a boiling point of about 100 to 250 ° C. and a mixture thereof can be preferably used. Specific examples include normal paraffin, isoparaffin, toluene, xylene, solvent naphtha, kerosene, mineral spirits, petroleum benzine and the like. If necessary, an alcohol-based or ester-based solvent may be added in a small amount (about 5% or less) to assist the pigment dispersion. The colored metallic pigment thus obtained has fine and uniform coloring pigments attached to its surface.
Shows a vivid color tone.

As a method of coating the colored metallic pigment obtained by adhering the surface-treated colored pigment on the surface of the metallic pigment as described above with a polymer, the colored metallic pigment is a hydrocarbon type or alcohol type solvent (preferably Is a hydrocarbon solvent) and a polymerizable monomer and a polymerization initiator, for example, benzoyl peroxide, isobutyl peroxide, azobisisobutyronitrile, etc. are added to the dispersion dispersed therein,
A method of heating with stirring to polymerize the monomer in-situ and depositing it on the surface of the colored metallic pigment particles is preferable. As the dispersion of the colored metallic pigment, the dispersion obtained in the step of adhering the surface-treated colored pigment to the metallic pigment may be used as it is, or the dispersion may be once solid-liquid separated into a paste or powder. The colored metallic pigment may be dispersed again in a solvent. The polymerization reaction is preferably carried out in an oxygen-free atmosphere, for example, an inert gas such as nitrogen or argon. Reaction temperature is 50
It is suitable to be up to 150 ° C, more preferably 70 to 100 ° C. If the temperature is too low, the polymerization reaction does not occur efficiently, and if it is too high, the reaction proceeds at once and the polymer cannot be deposited on the surface of the metallic pigment. The reaction time is preferably about 0.5 to 24 hours.
If the reaction time is too short, the monomers cannot be sufficiently polymerized, and there is no particular advantage if the reaction time is 24 hours or more.

After the polymerization reaction is completed, most of the solvent is removed from the dispersion by using a filtration device to obtain a paste.
Such a paste-like colored metallic pigment can be used as it is when used in a general paint,
When used for powder coatings, the colored metallic pigment in paste form is mixed under reduced pressure (less than atmospheric pressure) and heated (50 to 150 ° C.) to further remove the solvent, and the solvent content is 5% by weight or less. It is desirable that the powder form is preferably 2% by weight or less. A filter press, a pan filter or the like can be used as the filtering device. A vacuum kneader mixer, a vacuum dryer or the like is effective for heating and mixing under reduced pressure. This step is performed under reduced pressure,
It is safer than the spray drying method.

The conventional metallic pigments have a problem that additives such as oleic acid react with each other when they are made into a powder form and agglomerate. However, according to the production method of the present invention, each metallic pigment is encapsulated with a polymer. Since it has been converted, it hardly causes aggregation. Therefore, even when powder coating is performed, a smooth coating film having no spots can be obtained. The polymer coating amount for preventing agglomeration is 0.5 parts by weight or more per 100 parts by weight of the colored metallic pigment to which the coloring pigment is attached.

The colored metallic pigment of the present invention is mainly used in powder coatings. Two or more kinds of colored metallic pigments may be mixed, and by mixing two or more kinds, a special powder coating film having a polychromatic effect in which the color changes depending on the viewing direction is obtained.

Typical blending methods for powder coatings are a melt blending method in which a coating resin is melted, kneaded and dispersed with a pigment, and then pulverized to obtain a powder coating, and a powder resin is powdered and then dry mixed with a pigment. Although the dry blending method is used to prepare a powder coating, the colored metallic pigment of the present invention is most suitable for the dry blending powder coating. The melt blending method is not so preferable because the flake powder is deformed or broken in the step of kneading and pulverizing the colored metallic pigment. The blending amount of the colored metallic pigment is 100 resin powders.
0.1 to 30 parts by weight, preferably 1 to 2 parts by weight
0 parts by weight is suitable. If the content is too small, a sufficient decorative effect cannot be obtained, and if the content is too large, the physical properties of the powder coating film (weather resistance, corrosion resistance, mechanical strength, etc.) are adversely affected.

Examples of the coating resin powder used in the present invention include the following types: acrylic resin,
Alkyd resin, polyester resin, polyurethane resin, polyvinyl acetate resin, polyvinyl chloride resin, epoxy resin, nitrocellulose resin, fluororesin.

The particle size of the coating resin powder is from 1 to 10
It is preferably about 0 μm. If the particle size is too small, dust is likely to stand up and aggregation is likely to occur. If the particle size is too large, color unevenness is likely to occur.

The following components may be added to the coating resin powder: 1) Pigment / dye: phthalocyanine, quinacridone, isoindolinone, perylene, azo lake, iron oxide, yellow lead,
Coloring pigments such as carbon black, titanium oxide, pearl mica, bentonite, alumina white, extender pigments such as calcium carbonate, oil-soluble dyes, etc. 2) Additives: stabilizers, surfactants, curing agents, UV absorbers, leveling Agents, thickeners, etc.

As a coating method of the powder coating material, a fluidized dipping method,
Although the electrostatic powder coating method can be applied, the electrostatic powder coating method is more preferable because of its excellent coating efficiency. The electrostatic powder coating method includes a corona charging method and a friction charging method, but any coating method can be used.

[0037]

[Operation / Effect] When a powder coating material is prepared using the colored metallic pigment for powder coating material of the present invention, a powder coating film having excellent saturation can be obtained.

The colored metallic pigment for powder coatings of the present invention has little aggregation, and a smooth powder coating film with no spots can be obtained.

Since the surface of the colored metallic pigment for powder coating of the present invention is coated with a polymer synthesized from a polymerizable monomer, leakage of electric current through the metallic pigment during electrostatic powder coating is prevented. The adhesion efficiency is good.

According to the present invention, since a wide range of color pigments can be used, all colors are possible.

According to the production method of the present invention, almost all of the added coloring pigment can be adsorbed on the metallic pigment, so that stable quality can be obtained. Further, it is safe because the solvent removal step is performed under reduced pressure.

By mixing two or more kinds of the colored metallic pigments for powder coating of the present invention, it is possible to obtain a powder coating film having a special polychromatic effect in which the color changes depending on the viewing direction.

[0043]

【Example】

(Example 1) 1 g of a commercially available diketopyrrolopyrrole red pigment (IRGAZIN DPPRED BO manufactured by Ciba-Geigy Co., Ltd.), 0.5 g of benzoic acid (50 parts by weight per 100 parts by weight of pigment),
Mineral spirit 10g was added, glass beads with diameter 1mm was inserted 200g, diameter 5cm, internal volume 300cc
Ball mill dispersion was carried out for 24 hours with the pot mill. afterwards,
A commercially available aluminum paste (manufactured by Toyo Aluminum Co., Ltd., MG1000-70% metal content, average particle size: 30 μm, average thickness: 1 μm, specific surface area: 1.
4 m ² / g) (11.4 g (10 g as a metal content)) and mineral spirit (20 g) were added, and the mixture was further ball-milled for 1 hour. The obtained slurry was washed with 70 g of mineral spirits to separate it from the glass beads, and the aluminum flakes were precipitated by allowing it to stand for a while. The supernatant of the slurry was transparent, and all the pigments adhered to the aluminum flakes. . The amount of pigment deposited on the aluminum flakes is 0.07 g / m ² .

A slurry containing 10 g of the above colored metallic pigment was added to 0.25 g of methyl methacrylate, 0.25 g of 1,6-hexanediol diacrylate and 0.25 of styrene.
g, 0.25 g of acrylic acid (total of monomers: 10 parts by weight with respect to 100 parts by weight of colored metallic pigment to which a coloring pigment is attached), and heated at 80 ° C. in nitrogen with stirring, and azobis as a polymerization initiator Isobutyronitrile 0.
The monomer was polymerized by adding 05 g and reacting for 12 hours, and the polymer was deposited on the surface of the colored metallic pigment. After processing, the slurry is separated into solid and liquid, and the solid content is 50%.
Of paste.

The paste composition obtained was inserted into a vacuum mixer, kept under a reduced pressure of 10 ^-1 Torr, and kneaded for 5 hours while heating at 90 ° C. to obtain a powder coating composition having a solvent content of 0.1%. A colored metallic pigment for use was obtained. When the colored metallic pigment for powder coating was observed with an optical microscope, the red pigment was found to be attached to each particle.

Example 2 0.1 g of dialkoxyaluminum alkyl acetoacetate (Plainact ALM, Ajinomoto Co., Inc.) as a chelate compound in addition to benzoic acid.
A colored metallic pigment for powder coating having a solvent content of 0.2% was obtained in the same manner as in Example 1 except that (10 parts by weight based on 100 parts by weight of pigment) was added. When the obtained colored metallic pigment for powder coating was observed with an optical microscope, the colored pigment was uniformly attached to each metallic pigment.

Examples 3 to 12 and Comparative Examples 1 to 3 Example 1 except that the types of coloring pigment, monobasic aromatic carboxylic acid and chelate compound were changed as shown in Table 1.
The colored metallic pigments of Examples 3 to 12 and Comparative Examples 1 to 3 were prepared in the same manner as in.

Table 1 also shows the composition of the colored metallic pigment and the adhered state of the colored pigment observed by an optical microscope.

[0049]

[Table 1]

(Type of Coloring Pigment) Diketopyrrolopyrrole: IRGAZI, Ciba-Geigy Japan Co., Ltd.
N DPP RED BO Phthalocyanine Green: BASF Japan Ltd. HELI
OGEN GREEN L6900 Perylene Red: BASF Japan PALIOGEN RED
L3910HD Isoindolinone: BASF Japan PALIOTOLY
ELLOW L1820 Titanium oxide: Ishihara Sangyo Co., Ltd., ultrafine particle titanium oxide TTO (type of chelate compound) A: dialkoxyaluminum alkyl acetoacetate (Plainact ALM, Ajinomoto Co., Inc.) B: dialkoxytitanium bisacetylacetonate (Kawaken Fine Chemicals ( Alcofine TIA-
2) (Evaluation of adhesion state of pigment) 5: Pigment adheres finely and uniformly to the entire surface of each flake 4: Pigment adheres to the entire surface of each flake, but the adhesion state is not uniform 3: To each flake Pigment adheres like islands 2: Flakes with pigment adhering and flakes without adhering are mixed 1: No pigment adheres.

(Examples 13 to 24, Comparative Examples 4 to 6) Using the colored metallic pigments of Examples 1 to 12 and Comparative Examples 1 to 3, powder coatings were prepared under the following conditions, and a corona charging type static paint was prepared. A mild steel plate was coated with an electric powder coating machine (model name: MPSI-C type Matsuo Sangyo Co., Ltd.) to prepare a powder coating film.

[0052]   <Composition of powder coating>       Colored metallic pigment: 4 parts by weight       Uncolored polyester resin-based coating powder (average particle size 35 μm): 96 weight Department The powder was mixed with a small V-type mixer to prepare a paint.

<Painting conditions and baking conditions> 100V
Electrostatic powder coating was performed at an applied voltage of, and baked at 180 ° C. for 20 minutes.

Comparative Example 7 Colored polyester resin coating powder 96 in which 0.38 parts by weight of a red pigment (Diketopyrrolopyrrole IRGAZIN DPP RED BO) was added in place of the uncolored polyester resin coating powder. .38
In the same manner as in Example 13 except that 9.62 parts by weight of uncolored aluminum flakes (Toyo Aluminum Co., Ltd. MG1000 dispersed in acetone and suction-filtered with a glass filter to be powdered) were used as the metallic pigment. To prepare a powder coating film.

Table 2 shows the results obtained by visually observing the color tones of the coating films obtained in Examples 13 to 24 and Comparative Examples 4 to 5 and evaluating them in five levels.

[0056]

[Table 2]

Examples 25 to 26 and Comparative Examples 8 to 10 Mineral spirit was added as a solvent to the colored metallic pigments obtained in Example 1 to prepare three colored metallic pigments having different solvent contents. 4 parts by weight of these colored metallic pigments were collected as solids, 96 parts by weight of uncolored polyester resin powder were added, and mixed by a V-type mixer to prepare a powder coating material. This paint was applied in the same manner as in Example 1 and baked to form a powder coating film. Table 3 shows the appearance of the obtained coating film.

[0058]

[Table 3]

(Examples 27 to 29, Comparative Examples 11 to 12)
Five colored metallic pigments having different amounts of attached polymer were prepared in the same manner as in Example 1 except that the amount of the polymerizable monomer added was changed. Using the obtained colored metallic pigment, a powder coating film was prepared in the same manner as in Example 13, and its appearance was determined to be 3 of saturation, metallic feeling and luster.
The items were evaluated. The evaluation was a five-level evaluation, and items recognized as good were rated 4 or higher. The withstand voltage of each colored metallic pigment was measured by the method described below.

-Method for Measuring Withstand Voltage of Metallic Pigment- A coating material containing a sample metallic pigment was prepared with the following composition, and the withstand voltage was measured using the withstand voltage measuring device shown in FIG.

Acridic 47-712: 80 parts by weight (Dainippon Ink and Chemicals, Inc. acrylic resin varnish) Super Beckamine J-820: 20 parts by weight (Dainippon Ink and Chemicals, melamine resin varnish) n-Butyl alcohol: 25 parts by weight Metallic pigment: 3.75 parts by weight The measurement was performed according to the following procedure: (1) Enclose the paint to be measured in a glass tube, (2) Apply a voltage of 5 kV to the paint, Hold for 1 minute while checking for current leakage with an ammeter. (3) If there is no current leakage, increase the applied voltage by 5 kV.
Repeat steps (1) and (2). (4) From then on, increase the applied voltage by 5 kV to 120 kV and perform steps (1) and (2) to obtain the maximum voltage at which current leakage does not occur. The withstand voltage value of the metallic pigment is used.

The results are shown in Table 4. In Table 4, the monomer addition amount and the polymer adhesion amount are parts by weight with respect to 100 parts by weight of the colored metallic pigment to which the colored metallic pigment is attached. The amount of adhering polymer was calculated by obtaining the metal content of the colored metallic pigment by atomic absorption spectrometry and subtracting the amount of the added pigment from the content of the components other than the metal.

[0063]

[Table 4]

Example 30 As the colored metallic pigment, 2 parts by weight of the colored metallic pigments obtained in Examples 3 and 7 were mixed, and the coating powder had a particle size of 50 μm.
A powder coating film was prepared in the same manner as in Example 13 except that the acrylic polymer-based coating powder of m. The obtained coating film had a good appearance and had a special multicolor effect in which the color varied depending on the viewing direction.

[Brief description of drawings]

FIG. 1 is a schematic view of a withstand voltage measuring device that operates in an example.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) C09C 1/62 C09C 3/00 C09D 5/00 C09D 5/03

Claims (5)

(57) [Claims] 1. The surface of a colored metallic pigment, in which a colored pigment is attached to the surface of a base metallic pigment, is covered with a polymer synthesized from a polymerizable monomer by in-situ polymerization, and the residual solvent amount is 5% by weight or less. der Ru a powder paint colored metallic pigment, the colored pigment is non-polar
Monobasic aromatic carboxylic acid dispersed and formed in a basic solvent
Coating layer or monobasic aromatic carboxylic acid and aluminum
Has a coating layer of um or titanium chelate compound
The colored metallic pigment for powder coatings as described above . 2. The monobasic aromatic carboxylic acid is benzoic acid,
The colored metallic pigment for powder coating according to claim 1 , which is at least one selected from aminobenzoic acid, aminohydroxybenzoic acid, naphthoic acid, aminonaphthoic acid, cinnamic acid and aminocinnamic acid. 3. The withstand voltage is 80 kV or more.
2. A colored metallic pigment for powder coating according to any one of 2 above. 4. A. In the presence of a monobasic aromatic carboxylic acid, or a monobasic aromatic carboxylic acid and an aluminum or titanium chelate compound, the color pigment is dispersed in a nonpolar solvent to form a monobasic aromatic carboxylic acid on the surface of the color pigment. Forming a coating layer of 1. or a coating layer of a monobasic aromatic carboxylic acid and an aluminum or titanium chelate compound to produce a dispersion of a surface-treated color pigment, b. a step of adding and mixing a metallic pigment to the dispersion of the surface-treated color pigment of a, and depositing the surface-treated color pigment on the surface of the metallic pigment; c. The polymerizable monomer and the polymerization initiator are added to the metallic pigment to which the surface-treated color pigment of b is attached, and this is heated with stirring to synthesize a polymer from the polymerizable monomer.
Depositing the polymer on the surface of the colored metallic pigment; d. a step of solid-liquid separating the dispersion containing the colored metallic pigment to which the polymer of c is adhered into a paste by using a filtering device; e. step pasty colored metallic pigment d and heated with mixing under reduced pressure to remove the solvent fraction, consisting of capital claims 1-3 or method of manufacturing a powder coating colored metallic pigment according to the. 5. A 0.1 to 30 parts by weight for powder coatings colored metallic pigment according to any one of claims 1 to 3 powder coating composition comprising 100 parts by weight paint resin powder are dry mixed.