JP2003213157A - Metallic pigment, coating material composition containing the same, powdery coating material composition, and coating film containing the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a metallic pigment which can be suitably used in a powdery coating material composition and gives a metallic feel and a high brightness feel. <P>SOLUTION: The metallic pigment forms a coating film of a monolayer or a multilayer in which surfaces of aluminum particles are coated with the aluminum particles as substrate particles, wherein at least one of the monolayer or multilayers comprises a resin composition containing a fluororesin having a fluorinated alkyl group in the molecule. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallic pigment that gives a coating film a high-luminance feeling. More specifically, the present invention relates to a metallic pigment provided with a coating film made of a resin composition containing a fluororesin having a fluorinated alkyl group in its molecule.

The present invention also relates to a coating composition, a powder coating composition and a coating film containing the above metallic pigment.

[0003]

2. Description of the Related Art In recent years, powder coating compositions have attracted attention because of their characteristics as low-pollution coatings that do not use organic solvents, such as automobile parts, home appliances, furniture, machine tools, office equipment, building materials and toys. Demand is increasing in many industrial fields of.

Since the powder coating composition generally does not use an organic solvent and does not cause an environmental problem or a disaster due to the organic solvent, it can be said to be a coating composition friendly to the global environment and humans. Further, unlike the solvent type coating composition, the powder coating composition can be collected and cleaned relatively easily without the work environment being contaminated due to scattered adhesion during coating. Furthermore, the problem of wastewater treatment that occurs in the case of a water-soluble coating composition does not occur.

[0005] The coating with the powder coating composition is 1
The coating film formed by one-time coating is thick, and it is not necessary to repeat the coating as many times as in the conventional solvent-based coating composition, so that the coating time can be shortened. Further, since the powder coating composition does not contain a solvent in the coating composition, it has an advantage that pinholes are less likely to occur in the coating film.

Further, in the coating operation of the powder coating composition, the oversprayed coating composition can be recovered and reused, so that the loss of the coating composition can be remarkably reduced and the coating process can be performed. This can lead to cost reduction.

In the past, most powder coating compositions were powder coating compositions containing no metallic pigment such as metal powder. Further, in such a powder coating composition containing no metal powder, the coating properties and coating film properties of the powder coating composition are generally good, and they are significantly inferior to ordinary solvent-based coating compositions. There was no.

[0008] In recent years, due to the refinement of consumers' aesthetic consciousness accompanying the improvement of living standards, the demand for metallic-like coating films with excellent aesthetics is increasing in many industrial fields including the automobile industry. . In order to meet such demands of consumers, a powder coating composition that gives a metallic coating film with high designability, that is, a powder metallic coating composition that is a powder coating containing a metallic pigment, has been developed. Have been introduced and are being actively introduced in several industrial fields.

However, in the case of a powder coating composition containing a metallic pigment, if the metallic pigment cannot be arranged in parallel with the base material of the coating film, the color tone of the coating film will be dark, and it will be insufficient. There is a drawback that a metallic feeling cannot be obtained. Therefore, many research and development efforts have been made in various fields in order to overcome the drawbacks of the powder metallic pigment composition.

As a method for producing a powder metallic coating composition that has been conventionally developed, a melt blending method in which a metal flake pigment is sufficiently kneaded with a resin or a coloring pigment in advance by a melting method and then powdered by pulverization or the like, resin powder And a flake pigment are mixed and coated, and a bonded method in which a resin powder having a metal flake pigment adhered to the surface is used (JP-A-51-137725 and JP-B-57-35214). Japanese Patent Laid-Open No. 9-71
734, U.S. Pat. No. 4,138,511, etc.).

However, in the melt blending method, the metallic pigment is likely to be deformed in the kneading step and the subsequent step of adjusting the particle size of the resin powder by pulverization. Therefore, the appearance of the coating film obtained by coating the powder metallic coating composition produced by this method cannot be said to be sufficiently good. Further, in this manufacturing method, when aluminum particles are used as the metallic pigment, the active surface of aluminum is exposed in the pulverizing step, and the risk of ignition, dust explosion, etc. increases.

Further, the dry blending method has an advantage that the metallic pigment is relatively unlikely to be deformed. However, when the powder coating composition is applied by electrostatic coating, the metallic pigment needs to be charged at the time of coating. Therefore, when a metal pigment such as aluminum particles is used as the metallic pigment, the metallic pigment is previously prepared. The surface of the must be coated with resin. In addition, since the charge ratio of the metallic pigment and the resin powder is different,
The phenomenon of separation of resin powder and metallic pigment is likely to occur during coating. As a result, the design of the coating film deteriorates, and the content of the metallic pigment in the powder coating composition changes before and after coating, and the color tone changes when the coating material is collected and used. There is a problem that it is impossible.

Further, as the bonded method, a method of adhering the metallic pigment to the surface of the resin powder with a brush polisher, or a method in which the resin powder is brought into contact with a dispersion medium such as alumina balls coated with the metallic pigment to make the metallic pigment on the resin powder There is a method of transferring and binding. This method has the advantage that the introduction rate of the metallic pigment into the coating film is stable and the powder coating composition recovered without adhering to the substrate can be reused.

However, in these bonded methods, since the metallic pigment and the resin powder are pressure-bonded to each other by physical stress, deformation of the metallic pigment is likely to occur,
It is hard to get a good metallic feel. Furthermore, since the bonding strength is weak, there is an advantage that bonding (blocking) between resin powders is unlikely to occur, but it is actually difficult to bond all metallic pigments with a wide particle size distribution to the resin powder. Therefore, many particles of free metallic pigment that do not bond with the resin powder also remain.

When the amount of free metallic pigment increases, the mixing ratio of the resin powder and the metallic pigment changes when the paint is recovered and used due to the difference in adhesion efficiency. Cannot be used.
Furthermore, when a metallic pigment such as aluminum particles is used as the metallic pigment, since there are many free metallic pigments, there is a high risk of ignition, dust explosion and the like.

The weak binding force between the resin powder and the metallic pigment is particularly remarkable when the particle size of the metallic pigment is large, and the excellent luster achieved only by using the metallic pigment having such a large particle size. There is a problem that it is difficult to obtain the feeling and high brightness with the bonded aluminum obtained by these methods.

As described above, there are various methods for producing powdery metallic coatings, and any of them can be used to obtain a coating film which is sufficiently satisfactory in terms of color tone as well as metallic feeling and glittering feeling. Not not.

[0018]

From the above viewpoints, although there is a strong demand for the development of a powder coating composition in which the metallic feeling and glitter of the coating film are improved, such a powder coating composition is required. The composition has not yet been developed.

Therefore, a main object of the present invention is to provide a metallic pigment which can be suitably used in a powder coating composition and which gives a coating film an excellent metallic feeling and high brightness feeling.

Another object of the present invention is to provide a coating composition which gives a coating film an excellent metallic feeling and high brightness feeling. Similarly, another object of the present invention is to provide a powder coating composition which gives a coating film an excellent metallic feeling and high brightness feeling.

Further, another object of the present invention is to provide a coating film having excellent metallic feeling and high brightness feeling.

[0022]

In order to solve the problems of the prior art, the inventors of the present invention have made various improvements in the composition of the resin composition for coating the surface of the aluminum particles used as the base particles of the metallic pigment. , And repeated research and development. As a result, by coating the surface of the aluminum particles with a resin composition containing a fluororesin having a fluorinated alkyl group in the molecule, it can be suitably used in the powder coating composition, and in the coating film The present invention has been completed by finding that a metallic pigment giving a high brightness feeling can be obtained.

That is, the metallic pigment of the present invention is a metallic pigment in which aluminum particles are used as base particles and a single-layer or multi-layer coating for coating the surfaces of the aluminum particles is formed. At least one layer of the coating film is characterized by comprising a resin composition containing a fluororesin having a fluorinated alkyl group in the molecule.

Here, the content of the coating film made of the resin composition containing the fluorine-based resin is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the aluminum particles. Further, this fluorine-based resin has C1 to C
It is preferable that the resin is obtained by homopolymerizing or copolymerizing acrylic acid and / or methacrylic acid ester of fluorinated alkyl alcohol in which a part or all of hydrogen atoms of the alkyl alcohol of 20 are substituted with fluorine atoms.

Further, it is recommended that the fluororesin be a resin obtained by homopolymerizing or copolymerizing trifluoroethyl methacrylate and / or perfluorooctylethyl acrylate.

The present invention also includes a coating composition containing the metallic pigment of the present invention and a binder. further,
The present invention includes a powder coating composition containing the metallic pigment of the present invention and a thermosetting resin powder.

Here, the thermosetting resin powder preferably contains an acrylic resin or a polyester resin. Further, it is recommended that the metallic pigment of the present invention be contained in an amount of 1 to 40 parts by mass with respect to 100 parts by mass of the thermosetting resin powder.

The present invention is a coating film formed by the powder coating composition of the present invention, wherein the correlation between the L value by the L ^* a ^* b ^* colorimetric system and the observation angle (θ) is as follows. It includes a coating film having a value of β / α of 180 or more when approximated by the formula L = [β / (θ ² + α)] + γ.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail by showing embodiments.

<Metallic Pigment> The metallic pigment of the present invention is a metallic pigment in which aluminum particles are used as base particles and a single-layer or multi-layer coating for coating the surface of the aluminum particles is formed. At least one layer of the coating film is characterized by comprising a resin composition containing a fluororesin having a fluorinated alkyl group in the molecule.

<Aluminum Particles> The metallic pigment of the present invention uses aluminum particles as base particles.

Here, the material of the aluminum particles (also referred to as the base aluminum particles) used as the base particles in the metallic pigment of the present invention is preferably pure aluminum. Aluminum has an excellent metallic luster,
This is because it has an excellent characteristic that it is easy to handle because it is inexpensive and has a small specific gravity. In this case, the purity of this pure aluminum is particularly preferably 99.3 mass% or more.

The material of the aluminum base particles is not limited to pure aluminum, but may be an alloy whose main component is aluminum. In this case, the material of this alloy is preferably an alloy of aluminum and one or more metals selected from the group consisting of metals such as zinc, copper, bronze, nickel, titanium and stainless.

The shape of the aluminum base particles is
The shape is not particularly limited, and may be various shapes such as granular, plate-like, lump-like, and flaky (scaly). However, in order to give the coating film excellent brightness, it is preferably flake-like. preferable.

The average particle size of the base aluminum particles is not particularly limited, but is preferably 1 μm or more, and more preferably 3 μm or more. The average particle size is preferably 100 μm or less, and more preferably 50 μm or less. If the average particle size is less than 1 μm, it is difficult to handle in the manufacturing process and the particles tend to aggregate. If the average particle size exceeds 100 μm, the surface of the coating film when used as a paint In some cases, it may become rough and a desirable design may not be realized.

The average thickness of the base aluminum particles is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.02 μm or more. The average thickness is preferably 5 μm or less, and more preferably 2 μm or less. If this average thickness is less than 0.01 μm, handling in the manufacturing process is difficult and particles tend to aggregate. If this average thickness exceeds 5 μm, the coating film may have a noticeable graininess or hiding. There is a case where the strength is insufficient and a preferable design cannot be realized.

The average particle size of the base aluminum particles can be obtained by calculating the volume average from the particle size distribution measured by a known particle size distribution measuring method such as a laser diffraction method, a micromesh sieve method and a Coulter counter method. The average thickness is calculated from the hiding power and density of the aluminum base particles.

On the surface of the aluminum base particles,
A grinding aid added at the time of grinding may be adsorbed. Examples of the grinding aid include fatty acids such as oleic acid, stearic acid, linoleic acid, linoleic acid, ricinoleic acid, elaidic acid, zomarinic acid, gadoleic acid, and erucic acid, and aliphatic amines, fatty acid amides, and aliphatic acids. Examples thereof include alcohols and ester compounds.

The amount of these grinding aids adsorbed varies depending on the application and is not particularly limited, but these grinding aids suppress the unnecessary oxidation of the surface of the aluminum particles of the base material and improve the gloss. Have. The adsorption amount of these grinding aids is preferably less than 2 parts by mass with respect to 100 parts by mass of the base aluminum particles. If the amount is 2 parts by mass or more, the surface gloss may decrease.

Further, the base aluminum particles may have a color pigment layer or an interference film formed on the surface thereof. By providing the color pigment layer or the interference film in this way, the base aluminum particles can be colored, and a coating film having a unique design can be formed.

Here, the color pigment which can be used for providing the color pigment layer is not particularly limited, but for example, quinacridone, diketopyrrolopyrrole,
Isoindolinone, indanthrone, perylene, perinone, anthraquinone, dioxazine, benzimidazolone, triphenylmethanequinophthalone, anthrapyrimidine, yellow lead, pearl mica, transparent pearl mica, colored mica, interference mica, phthalocyanine, halogenated phthalocyanine, Examples thereof include azo pigments (azomethine metal complex, condensed azo, etc.) titanium oxide, carbon black, iron oxide, copper phthalocyanine, condensed polycyclic pigments, and the like.

As a method of providing this interference film,
Although not particularly limited, for example, a method of sputtering a thin film made of a dissimilar metal on the surface of the base aluminum particles may be used. And, as the dissimilar metal used at that time, although not particularly limited,
For example, gold, silver, copper, nickel, cobalt, titanium,
In addition to aluminum, copper alloys such as brass, iron alloys such as stainless steel, nickel alloys such as Hastelloy can be cited.

The method of producing the aluminum base particles is not particularly limited and can be produced by a known method. Specific examples include a gas atomizing method, a water atomizing method, a rotating disk method, a step of producing an aluminum powder, preferably an aluminum spherical powder by a melt spinning method, and a step of grinding the aluminum powder by a known ball mill method. And a method for producing aluminum particles.

<Fluorine Resin> The fluorine resin used in the present invention must be a fluorine resin containing a fluorinated alkyl group in the molecule.

Here, in the fluorine-based resin used in the present invention, the site where the fluorinated alkyl group is present is not particularly limited and may be part or all of the main chain, or part or all of the side chain. May be

When the fluororesin used in the present invention is a fluororesin whose fluoroalkyl group constitutes a part or the whole of the main chain, the raw material monomer for the fluororesin is not particularly limited. However, examples thereof include tetrafluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, hexafluoropropylene, and hexafluoropropylene oxide. Here, these raw material monomers may be used alone or in combination of two or more kinds,
Further, it may be used together with other raw material monomers. The other raw material monomer includes a general polymerizable raw material monomer containing no fluorine and a crosslinking agent.

When the fluororesin used in the present invention is a fluororesin in which the fluoroalkyl group constitutes a part or all of the side chain, the raw material monomer of the fluororesin is not particularly limited. However, for example, methacrylic acid ester of perfluoroalkyl alcohol, acrylic acid ester of perfluoroalkyl alcohol,
Perfluoroalkyl vinyl ether etc. are mentioned.

Among these, particularly C1 to C20
It is preferable that the resin is obtained by homopolymerizing or copolymerizing acrylic acid and / or methacrylic acid ester of a fluorinated alkyl alcohol in which a part or all of hydrogen atoms of the alkyl alcohol is substituted with a fluorine atom.

More specifically, the raw material monomers that can be used here are trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,4,4,4. -Hexafluorobutyl methacrylate, perfluorooctylethyl methacrylate, trifluoroethyl acrylate, 2,
2,3,3-tetrafluoropropyl acrylate,
2,2,3,4,4,4-hexafluorobutyl acrylate, perfluorooctylethyl acrylate, perfluoropropyl vinyl ether and the like can be mentioned.
Here, these raw material monomers may be used alone or in combination of two or more, and may be used together with other raw material monomers. The other raw material monomer includes a general polymerizable raw material monomer containing no fluorine and a crosslinking agent.

The fluorine content of the fluororesin used in the present invention is preferably 10% by mass or more,
In particular, it is more preferably 20% by mass or more.

When the fluorine content is less than 10% by mass, the effect of the present invention cannot be fully exhibited, and thus a coating film having a sufficient sense of brightness tends not to be obtained. Further, the maximum fluorine content is when the fluorine-based resin used in the present invention is a tetrafluoroethylene homopolymer,
Since the fluorine content in this case is 76% by mass, this fluorine content will not exceed 76% by mass.

<Film Made of Resin Composition Containing Fluorine Resin> A film made of a resin composition containing a fluorine resin used in the present invention (also referred to as fluorine film) is
It may contain only the fluorine-based resin used in the present invention, or may contain other resin composition and various additives in addition to the fluorine-based resin used in the present invention.

The content of the fluorine resin used in the present invention in the fluorine coating is preferably 50% by mass or more, and particularly preferably 70% by mass or more. If this content is less than 50% by mass, sufficient brightness tends not to be exhibited.

The amount of the fluorine-based coating formed on the surface of the base aluminum particles is preferably 0.1 part by mass or more based on 100 parts by mass of the aluminum particles,
In particular, it is more preferably 2.0 parts by mass or more. Further, the amount of the coating film is preferably 50 parts by mass or less, and particularly preferably 20 parts by mass or less. If the amount of this coating is less than 0.1 parts by mass, pinholes are likely to open in the coating, and it tends to be difficult to obtain a uniform coating, and a metallic pigment is added to the powder coating composition by the dry blending method. When mixed and powder coated, the metallic pigment tends to adhere to the gun and tends to cause spits. When the amount of the coating exceeds 50 parts by mass, the coating is too thick, so that the reflected light from the metallic pigment may be scattered and the luminance of the coating may decrease.

The metallic pigment of the present invention is a metallic pigment in which aluminum particles are used as base particles and a single-layer or multi-layer coating for coating the surfaces of the aluminum particles is formed. That is, in the metallic pigment of the present invention,
The surface of the base aluminum particles may be coated with only a single layer of a fluorine-based coating, and the base aluminum may be coated with a multi-layer including a layer of a fluorine-based coating and a layer of a coating of another resin composition. The surface of the particles may be coated. However, it is a necessary condition that the fluorine-based coating is the outermost layer.

Here, in the metallic pigment of the present invention, the surface of the base aluminum particles may be in direct contact with the layer of the fluorine-based coating, or may be required between the surface of the base aluminum particles and the layer of the fluorine-based coating. According to the above, a layer of a coating film of another resin composition may be provided. For example, the surface of the base aluminum particles is coated with a coating film of a resin composition having excellent chemical resistance and high barrier property, and a second layer of a fluorine-based coating film is further formed thereon. It is also possible to coat.

As described above, by using the metallic pigment of the present invention in which the aluminum base particles are coated with the multi-layer coating, the coating film is provided with an excellent brilliance and the like, and at the same time, other excellent additional characteristics are imparted. You can also do it.
For example, when a coating layer of a polybutadiene / acrylic cross-linking agent copolymer resin is provided between the surface of the base aluminum particles and the layer of the fluorine-based coating to coat the base aluminum particles, the resistance of the metallic pigment of the present invention to It is possible to improve chemical resistance, water resistance, weather resistance (stability over time) and the like.

The method for coating the surface of the base aluminum particles with the layer of the fluorine-based coating is not particularly limited as long as it is a method capable of forming a uniform coating of the resin composition on the surfaces of the metal particles, and it is known. Can be used.

For example, a step of dispersing the aluminum base particles in an organic solvent to obtain a slurry, and a step of adding a raw material monomer of the fluororesin used in the present invention to the obtained slurry to obtain a reaction solution While heating the obtained reaction solution in an inert gas atmosphere, a raw material monomer is polymerized by adding a polymerization initiator such as azobisisobutyronitrile (also abbreviated as “AIBN”) or benzoyl peroxide, to form a base aluminum. Examples include a method of coating the aluminum particles on the substrate, which comprises a step of depositing the fluorine-based resin used in the present invention on the surface of the particles.

In the above-mentioned method for coating the base aluminum particles, the solvent for dispersing the base aluminum particles is not particularly limited, but a solvent that does not dissolve the fluororesin used in the present invention is preferable. For example, isoparaffinic solvent, hexane, heptane, octane, nonane,
Aliphatic hydrocarbon solvents such as decane, undecane, dodecane, aromatic hydrocarbon solvents such as benzene, toluene, xylene, ether solvents such as diethyl ether,
Examples thereof include ester solvents such as ethyl acetate and butyl acetate, alcohol solvents such as methanol, ethanol, butanol, glycerin and polypropylene glycol. Further, these solvents may be used alone or in combination of two or more kinds.

The amount of these solvents used is preferably 300 parts by mass or more, and more preferably 400 parts by mass or more with respect to 100 parts by mass of the base aluminum particles. The amount used is preferably 1200 parts by mass or less, and more preferably 800 parts by mass or less. If the amount used is less than 300 parts by mass, the viscosity of the reaction solution tends to be too high, and it becomes difficult for the reaction components to diffuse uniformly. If the amount used exceeds 1200 parts by mass, the monomer concentration decreases. However, even if the reaction time is lengthened, a large amount of unreacted monomer tends to remain.

The polymerization initiator used in the above-mentioned method for coating the aluminum particles on the substrate is not particularly limited, and those generally known as radical generators can be used. Specific examples include peroxides such as benzoyl peroxide, lauroyl peroxide, isobutyl peroxide, and methyl ethyl ketone peroxide, and azo compounds such as azobisisobutyronitrile (also abbreviated as “AIBN”). To be

Here, the blending amount of the polymerization initiator is preferably 0.1 part by mass or more, and more preferably 0.5 part by mass or more based on 100 parts by mass of the fluorine-based coating. Further, the blending amount is preferably 10 parts by mass or less, and more preferably 8 parts by mass or less. If the blending amount is less than 0.1 parts by mass, the polymerization reaction may not proceed and the expected amount of the coating film may not be formed, and if the blending amount exceeds 10 parts by mass, the polymerization may be rapidly performed. Adhesion of the produced polymer to the base aluminum particles cannot be overtaken, free polymer particles are produced, the viscosity of the entire system rapidly increases, and in some cases, solidification occurs.

In the above-mentioned method for coating the base aluminum particles, the temperature of the polymerization reaction is defined by the kind of the initiator used. The half-life of the initiator is uniquely determined by the temperature, and the temperature at which the half-life of the initiator is 5 minutes or longer is preferable, and the temperature at which the half-life is 15 minutes or longer is particularly preferable. Further, this temperature is preferably a temperature at which the half-life of the initiator is 20 hours or less, more preferably 10 hours or less. For example, when AIBN is used as the initiator, the half-life is 60, 70, 80, 90.
22, 5, 1.2, 0.3 hours at 7 ° C, respectively
0-90 degreeC becomes a more preferable temperature range. If the reaction temperature is lower than the preferred temperature range, there may be a problem that the polymerization reaction does not proceed smoothly. If the reaction temperature exceeds the preferred temperature range, the polymerization reaction rapidly proceeds and the resulting polymer substrate There is a tendency that adsorption on the aluminum particles cannot catch up, free polymer particles are generated, the viscosity of the entire system rises sharply, and in some cases solidifies.

Further, the method of coating the surface of the base aluminum particles with the layer of the fluorine-based coating is not limited to the above-mentioned coating method of the base aluminum particles, and other than that, the fluorine-based resin composition used in the present invention can be used. It is also possible to use a method of depositing the fluororesin composition used in the present invention on the surface of the base aluminum particles by utilizing the difference in boiling point between the good solvent and the poor solvent.

For example, the surface of the base aluminum particles can be coated with a fluorine-based coating layer by the following method.

First step: First, a mixed solvent of a good solvent and a poor solvent for the fluororesin composition used in the present invention (however, a composition in which the fluororesin composition of the present invention must be dissolved) is used. The fluororesin composition of the invention is dissolved. At this time, the good solvent and the poor solvent are combined such that the boiling point of the good solvent is lower than the boiling point of the poor solvent. Then, the aluminum base particles are dispersed in this solution to obtain a slurry.

Second step: Next, the slurry obtained by dispersing the aluminum base particles is heated to selectively distill off the good solvent which is a low boiling point solvent, and the solvent composition of the slurry is the fluorine-based resin used in the present invention. The composition is changed to a composition in which the composition is deposited, and the fluorine-based resin composition used in the present invention is deposited on the surface of the base aluminum particles.

Here, when this method is used, it is preferable to select a combination of solvents having a large difference in boiling points. Further, this method is different from the above-mentioned method in that it has an advantage that it does not involve a polymerization reaction and does not require equipment for the polymerization.

<Coating Composition> The coating composition of the present invention contains the metallic pigment of the present invention and a binder.

Here, the coating composition of the present invention is not limited to a powder coating composition, and may be a general solvent-based coating composition containing a solvent, and an aqueous coating composition containing water. It may be a thing.

The binder used in the coating composition of the present invention is not particularly limited, and binders generally used in coating compositions containing metallic pigments can be preferably used. Specific examples include acrylic resins, polyester resins, alkyd resins, epoxy resins, fluororesins, lacquers that cure by natural drying, two-component polyurethane resins, silicone resins, and the like, and transparent resins are more preferable. . Where these binders are
They may be used alone or in combination of two or more.

When the coating composition of the present invention contains a solvent, the composition of the solvent is not particularly limited, and a solvent generally used for a coating composition containing a metallic pigment can be used. Specific examples include hexane, heptane, cyclohexane, octane, and other aliphatic hydrocarbon solvents, benzene, toluene, xylene, and other aromatic hydrocarbon solvents, mineral spirits and other aliphatic hydrocarbons and aromatic hydrocarbons. Mixed solvent with, halogenated hydrocarbon solvent such as chlorobenzene, trichlorobenzene, perchlorethylene, trichloroethylene, methanol,
Solvents consisting of alcohols such as ethanol, n-propyl alcohol, n-butanol, ketones such as n-propanone and 2-butanone, esters such as ethyl acetate and propyl acetate, tetrahydrofuran, diethyl ether, ethylpropyl Examples thereof include solvents such as ethers and ethers. These solvents are
It is preferable to use a mixture of two or more kinds, and the composition of the solvent is
It is determined in consideration of solubility with respect to a binder for paints, coating film forming characteristics, coating workability and the like.

Further, although the coating composition of the present invention has a unique color and does not contain a coloring pigment other than the metallic pigment of the present invention, it is possible to obtain a coating film having excellent brightness. Other color pigments may be included together. In that case, the metallic pigment of the present invention alone cannot be obtained,
It is possible to give various color tones.

Further, in the coating composition of the present invention, the color pigments which can be used other than the metallic pigment of the present invention are not particularly limited, and the coloring pigments generally used in coating compositions containing a metallic pigment can be used. . Specific examples include phthalocyanine, halogenated phthalocyanine, quinacridone, diketopyrrolopyrrole, isoindolinone,
Azomethine metal complex, indanthrone, perylene, perinone, anthraquinone, dioxazine, benzimidazolone, condensed azo, triphenylmethane, quinophthalone,
Examples thereof include anthrapyrimidine, titanium oxide, iron oxide, zinc white, cobalt blue, ultramarine blue, yellow lead, carbon black, and pearl mica.

In addition, the coating composition of the present invention may contain a dispersant, a curing agent, an ultraviolet absorber, an antistatic agent, an additive, and an additive as long as they do not impair the various colors of the coating film and the excellent brightness. Sticky agent, coupling agent, plasticizer, antioxidant,
Various additives such as polishes, synthetic preservatives, lubricants and fillers can be added.

<Powder Coating Composition> The powder coating composition of the present invention contains the metallic pigment of the present invention and a thermosetting resin powder.

Here, the thermosetting resin powder used in the present invention is not particularly limited and is a powder of a resin composition containing a resin that is melted by heating and then rapidly cured, and the metallic resin of the present invention is used. A thermosetting resin powder that does not affect the fluorine-based coating of the pigment can be used.

That is, as the thermosetting resin powder used in the present invention, a known thermosetting resin powder for powder coating can be particularly preferably used. Specific examples thereof include powder of a resin composition containing acrylic resin, polyester resin and the like.

If necessary, a curing agent, a dispersant or the like may be added to the thermosetting resin powder used in the powder coating composition of the present invention.

Here, the curing agent that can be added to the thermosetting resin powder used in the present invention is not particularly limited, and known curing agents can be used. Specific examples include amines, polyamides, dicyandiamides, imidazoles, carboxylic acid dihydrazides, acid anhydrides, polysulfides, boron trifluoride, amino resins, triglycidyl isocyanate, primides, epoxy resins, other dibasic acids, imidazolines. , Hydrazides, isocyanate compounds and the like. These curing agents may be used alone or in combination of two or more.
Furthermore, these curing agents can be used in combination with a curing accelerator, if necessary.

The dispersant that can be added to the thermosetting resin powder used in the present invention is not particularly limited, and known dispersants can be used. Specific examples include surfactants such as phosphoric acid esters, amines, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers and the like. These dispersants may be used alone or in combination of two or more.

Further, the thermosetting resin powder used in the powder coating composition of the present invention may contain, in addition to the above, if necessary.
Various fillers such as calcium carbonate, barium sulfate and talc, various fluidity regulators such as silica, alumina and aluminum hydroxide, titanium oxide, carbon black, iron oxide, copper phthalocyanine, azo pigments, condensed polycyclic pigments, etc. Various coloring agents, various leveling agents such as acrylic oligomers and silicones, various anti-foaming agents such as benzoin, and various additives such as waxes, coupling agents, antioxidants, magnetic powders, etc. A functional material may be added.

The average particle size of the thermosetting resin powder used in the powder coating composition of the present invention is not particularly limited, but is preferably 5 μm or more, and particularly 15 μm.
It is more preferably m or more. The average particle size is preferably 100 μm or less, particularly 60 μm.
The following is more preferable. This average particle size is 5 μm
If it is less than the above range, it may be difficult to form a uniform dust during powder coating, and a lump of resin may adhere to the coated plate, resulting in loss of smoothness. On the other hand, if the average particle size exceeds 100 μm, the smoothness of the surface of the powder coating film may be hindered and a good appearance may not be obtained.

In the powder coating composition of the present invention, the content of the metallic pigment of the present invention is 1 part by mass or more based on 100 parts by mass of the thermosetting resin powder used in the present invention. It is particularly preferable that the amount is 2 parts by mass or more. Further, this content is preferably 40 parts by mass or less, and more preferably 20 parts by mass or less. If the content is less than 1 part by mass, sufficient metallic feeling and brightness feeling may not be obtained, and the coating film thickness tends to be increased in order to conceal the substrate. When the content exceeds 40 parts by mass, the cost is increased, the smoothness of the coating film is lost, and the appearance tends to be deteriorated.

The method for producing the thermosetting resin powder used in the powder coating composition of the present invention is not particularly limited. For example, the powder coating composition of the present invention is prepared by the following method. The thermosetting resin powder used for the product can be manufactured.

Specifically, first, raw materials such as an acrylic resin, a polyester resin and the like, and a curing agent, a dispersant, a filler and the like, which are added as needed, are prepared, and these are first mixed with a mixer, a blender or the like. Dry blend. Next, the raw materials dry-blended by a kneader or the like are melt-mixed and cooled. Subsequently, the cooled melt-kneaded product is pulverized by using a mechanical or air flow type pulverizer.
Then, the crushed melt-kneaded product is classified by an airflow classifier to obtain the thermosetting resin powder of the present invention.

The mixing method of the thermosetting resin powder used in the powder coating composition of the present invention and the metallic pigment of the present invention is not particularly limited, and a known method can be used. Preferred examples include, for example, a method of mixing using a high speed mixer such as a Henschel mixer or a spar mixer, or a blender.

In the powder coating composition of the present invention, in addition to the metallic pigment of the present invention and the thermosetting resin powder used in the powder coating composition of the present invention, a coloring pigment or the like is added if necessary. You may. For example, organic pigments such as quinacridone red, phthalocyanine blue, phthalocyanine green, isoindolinone yellow, carbon black, perylene, azo lake, iron oxide, titanium oxide, cobalt blue, zinc white, ultramarine blue, chromium oxide, mica, and yellow lead. Inorganic pigments can be used. Further, these color pigments may be used alone or in combination of two or more.

Further, in the powder coating composition of the present invention, in addition to the metallic pigment of the present invention and the thermosetting resin powder used in the powder coating composition of the present invention, if necessary, UV absorption Agents, static eliminators, dispersants, antioxidants, polishes, surfactants, synthetic preservatives, lubricants, plasticizers, curing agents, fillers (strengthening agents) and the like can also be added.

<Method for coating powder coating composition> The method for coating the powder coating composition of the present invention is not particularly limited, and any coating method generally used for coating powder coating compositions can be used. However, for example, the surface of a material to be coated (also referred to as a base material) is subjected in advance to a known treatment such as blasting or chemical conversion treatment, and then the powder coating composition is attached thereto,
After that, a coating method of heating and curing by baking is preferable.

Here, the base material of the powder coating composition of the present invention is not particularly limited, but a base material made of a material which is not deformed or deteriorated by baking after coating of the powder coating composition of the present invention. Is preferred. For example, base materials made of known metals such as iron, copper, aluminum and titanium and various alloys are preferable.

As a method for adhering the powder coating composition of the present invention to the surface of the base material, a fluidized dipping method or an electrostatic powder coating method can be applied. It is excellent and more preferable. As the electrostatic powder coating method, known methods such as a corona discharge method and a triboelectric charging method can be used.

The heating temperature for baking and heating and curing the powder coating composition of the present invention can be appropriately set according to the type of thermosetting resin powder used, but it is usually preferably 120 ° C. or higher, Particularly, it is more preferably 150 ° C. or higher. The heating temperature is preferably 230 ° C or lower, and more preferably 200 ° C or lower. If the heating temperature is lower than 120 ° C, the crosslinking reaction (curing) will not proceed sufficiently and the desired coating film properties will not be obtained, and if the heating temperature exceeds 230 ° C,
The resin tends to yellow and become brittle.

The heating time for baking and heating and curing the powder coating composition of the present invention can be appropriately set depending on the kind of the thermosetting resin powder used and the heating temperature, but is usually 5
It is preferably at least minutes, more preferably at least 10 minutes. Further, this heating time is preferably 40 minutes or less, and particularly preferably 30 minutes or less. If this heating time is less than 5 minutes, the crosslinking reaction (curing) will not proceed sufficiently and desired coating film physical properties may not be obtained. If this heating time exceeds 40 minutes, the resin will become yellow. It tends to change or become brittle.

<Coating film> The coating film of the present invention is the powder coating of the present invention.
A coating film formed from the composition ^*a^*b^*Measurement
The correlation between the L value of the color system and the observation angle (θ) is L = [β / (θ²+ Α)] + γ When approximated by, the value of β / α becomes 180 or more.
And are characterized.

The thickness of the coating film of the present invention is not particularly limited, but is usually preferably 5 μm or more, and more preferably 10 μm or more. The thickness is preferably 200 μm or less,
In particular, it is more preferably 150 μm or less. If the thickness is less than 5 μm, there is a tendency that coating cannot be performed uniformly (color unevenness occurs or pinholes open).
There is a possibility that the advantage of powder coating that a thick coating film can be obtained by one coating may not be utilized. This thickness is 200
If the thickness exceeds μm, the amount of paint used increases and the cost increases, but the practical value tends to be lost.

The content of the base aluminum particles in the coating film of the present invention is not particularly limited, but is usually 1
It is preferably at least mass%, more preferably at least 2 mass%. Further, the content is preferably 20% by mass or less, and more preferably 10% by mass or less. If the content is less than 1% by mass, the hiding tends to be impossible, and if the content exceeds 20% by mass, the smoothness of the coated surface tends to be extremely lost.

The brightness of the coating film of the present invention is evaluated using the evaluation parameter β / α, which β / α is derived from the following equation (1). L = [β / (θ ² + α)] + γ ... Equation (1) In the equation (1), L is a spectrophotometer (trade name “X
-Rite MA68 "manufactured by X-Rite Co., Ltd., the lightness index (L ^* a ^* b ^* colorimetric system, which is a colorimetric system based on the uniform color space defined by 1976 by CIE). , Θ are observation angles, and α, β and γ are constants.

Here, the observation angle (θ) means that the regular reflection position when the incident light (measurement light) is irradiated at an angle of 45 ° to the surface of the coated plate is 0 ° (reference), and the normal side of the coated plate. Is a positive angle.

The first item of the equation (1) corresponds to metallic directional scattering that depends on the observation angle θ, and the second item corresponds to isotropic scattering that does not depend on the observation angle θ. Is. Visual brightness is the specular reflection position of directional scattering (θ = 0)
Since it correlates well with the L value at, that is, β / α, β / α
Is used as an evaluation parameter of the sense of brightness.

Regarding the calculation of β / α, it is first necessary to determine α, β and γ. In the present invention, first, the observation angle θ
Is measured at 15 degrees, 25 degrees, 45 degrees, 75 degrees, and 110 degrees, and it is assumed that the relationship between the θ values and the L values follows Equation (1). Determine γ.

With reference to FIG. 1 using the coating films of Example 2 and Comparative Example 1 which will be described later, as shown in FIG. 1, in the curve drawn by the above formula (1), this curve should be as measured as possible. Find α, β, and γ that pass above. Therefore, mantissas are substituted for α, β, and γ so that the residual sum of squares of the calculated value and the measured L value is minimized.
Perform the operation to determine the solution of by the solver.

The coating film of the present invention was formed by using the powder coating composition of the present invention containing the metallic pigment of the present invention in which pure aluminum was used as the material of the base aluminum particles and containing no coloring pigment. For a bank that is a coating film (also referred to as a silver metallic paint film), the evaluation parameter β / α representing the brightness of this coating film is β / α ≧ 1.
It is desirable that the formula 80 be satisfied, and it is more preferable that the formula be 200 or more.

The metallic pigment, coating composition, powder coating composition and coating film of the present invention obtained as described above are
It is applicable to coating in many industrial fields, and is suitably used for coating vehicle bodies such as automobiles, office supplies, household products, sports products, agrochemical materials, electric products, and the like.

[0106]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

Example 1 First, a metallic pigment paste (trade name 76) which is a paste of aluminum flakes.
40NS, Toyo Aluminum Co., Ltd. paste in which the volatile component was replaced with isoparaffin (nonvolatile component 66.9).
%) 179.4 parts by mass was dispersed in 612.8 parts by mass of isoparaffin.

Then, trifluoroethyl methacrylate (trade name: M-3F, manufactured by Kyoeisha Chemical Co., Ltd.) 2
1.6 parts by mass and trimethylolpropane triacrylate (trade name TMP-3A, manufactured by Osaka Organic Chemical Co., Ltd.)
2.4 parts by mass was added, and the mixture was heated to 80 ° C. with stirring.

Subsequently, 0.7 parts by mass of azobisisobutyronitrile (AIBN) was added as a polymerization initiator,
The reaction was carried out at 20 ° C. for 20 hours.

The obtained dispersion liquid is filtered and washed, and then the solvent is replaced with hexane, and the mixture is air-dried to give a powder.
What passed through a 50 μm screen was designated as metallic pigment (I). The content of the fluorine-based coating of the metallic pigment (I) is 1 with respect to 100 g of the base aluminum particles.
It was 5.0 g.

Next, 100 parts by mass of a polyester thermosetting resin powder (trade name: Teodur PE 785-900, manufactured by Takashi Kubo Paint Co., Ltd.) and 6 parts by mass of the metallic pigment (I) were mixed, A powder coating composition (I) was produced for each.

Further, the powder coating composition (I) was applied to a corona discharge type electrostatic powder coating machine (MXR-100VT-min).
i, manufactured by Matsuo Sangyo Co., Ltd., under the condition of applied voltage of 80 kV, material: tin plate, size: 100 × 200 mm
The coated plate (I) having a film thickness of 58 μm was prepared by coating the same on the substrate and baking at 190 ° C. for 20 minutes.

Example 2 First, a metallic pigment paste (trade name 76) which is a paste of aluminum flakes.
40NS, Toyo Aluminum Co., Ltd. paste in which the volatile component was replaced with isoparaffin (nonvolatile component 66.9).
%) 179.4 parts by mass was dispersed in 615.4 parts by mass of isoparaffin.

Then, 21.6 parts by mass of perfluorooctylethyl acrylate (trade name FA-108, manufactured by Kyoeisha Chemical Co., Ltd.) and trimethylolpropane triacrylate (trade name TMP-3A, Osaka Organic Chemical Co., Ltd.) were added. )) 2.4 parts by mass and 80% with stirring.
Warmed to ° C.

Subsequently, 0.7 parts by mass of azobisisobutyronitrile (AIBN) was added as a polymerization initiator,
The reaction was performed at 15 ° C for 15 hours.

The obtained dispersion is filtered and washed, and then the solvent is replaced with hexane, and the mixture is air-dried to give a powder.
What passed through a 50 μm screen was used as a metallic pigment (II). The content of the fluorine-based coating film of the metallic pigment (II) is 1 with respect to 100 g of aluminum particles.
It was 7.4 g.

Next, 100 parts by mass of a polyester thermosetting resin powder (trade name: Teodur PE 785-900, manufactured by Takashi Kubo Paint Co., Ltd.) and 6 parts by mass of the metallic pigment (II) were mixed, A powder coating composition (II) was produced in each case.

Further, the powder coating composition (II) was applied to a corona discharge type electrostatic powder coating machine (MXR-100VT-min).
i, manufactured by Matsuo Sangyo Co., Ltd., under the condition of applied voltage of 80 kV, material: tin plate, size: 100 × 200 mm
The coated plate (II) having a film thickness of 62 μm was prepared by coating the same on the substrate and baking at 190 ° C. for 20 minutes.

Example 3 First, a metallic pigment paste (trade name 14
40YL, Toyo Aluminum Co., Ltd. paste in which the volatile component was replaced with isoparaffin (nonvolatile component 70.0).
%) 171.4 parts by mass was dispersed in 622.6 parts by mass of isoparaffin.

Then, 21.6 parts by mass of perfluorooctylethyl acrylate (trade name FA-108, manufactured by Kyoeisha Chemical Co., Ltd.) and trimethylolpropane triacrylate (trade name TMP-3A, Osaka Organic Chemical Co., Ltd.) were added. )) 2.4 parts by mass and 80% with stirring.
Warmed to ° C.

Subsequently, 0.7 parts by mass of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and 80
The reaction was performed at 15 ° C for 15 hours.

The obtained dispersion liquid is filtered and washed, and then the solvent is replaced with hexane, and the mixture is air-dried to give a powder.
What passed through a 50 μm screen was used as a metallic pigment (III). The content of the fluorine-based coating film of the metallic pigment (III) was 16.7 g based on 100 g of the aluminum particles.

Next, 100 parts by mass of a polyester type thermosetting resin powder (trade name: Teodur PE 785-900, manufactured by Takashi Kubo Paint Co., Ltd.) and 6 parts by mass of the metallic pigment (III) were mixed, A powder coating composition (III) was produced in each case.

Further, the powder coating composition (III) was applied to a corona discharge type electrostatic powder coating machine (MXR-100VT-mi).
Ni, manufactured by Matsuo Sangyo Co., Ltd., applied voltage 80 kV
Material: Tin plate, Size: 100 × 200m
m and the substrate was baked at 190 ° C. for 20 minutes to prepare a coated plate (III) having a film thickness of 73 μm.

Example 4 First, a metallic pigment paste (trade name 71) which is a paste of aluminum flakes.
60N, Toyo Aluminum Co., Ltd. paste with volatile components replaced with isoparaffin (nonvolatile component 53.8)
%) 187.5 parts by mass was dispersed in 584.5 parts by mass of isoparaffin.

Then, 21.6 parts by mass of perfluorooctylethyl acrylate (trade name FA-108, manufactured by Kyoeisha Chemical Co., Ltd.) and trimethylolpropane triacrylate (trade name TMP-3A, Osaka Organic Chemical Co., Ltd.) were added. )) 2.4 parts by mass and 80% with stirring.
Warmed to ° C.

Subsequently, 0.7 parts by mass of azobisisobutyronitrile (AIBN) was added as a polymerization initiator,
The reaction was performed at 18 ° C for 18 hours.

The obtained dispersion is filtered and washed, and then the solvent is replaced with hexane, and the mixture is air-dried to give a powder.
What passed through a 50 μm screen was used as a metallic pigment (IV). The content of the fluorine-based coating film of the metallic pigment (IV) is 2 with respect to 100 g of the aluminum particles.
It was 1.5 g.

Next, 100 parts by mass of a polyester type thermosetting resin powder (trade name: Teodur PE 785-900, manufactured by Takashi Kubo Paint Co., Ltd.) and 6 parts by mass of the metallic pigment (IV) were mixed, A powder coating composition (IV) was produced in each case.

Further, the powder coating composition (IV) was applied to a corona discharge type electrostatic powder coating machine (MXR-100VT-min).
i, manufactured by Matsuo Sangyo Co., Ltd., under the condition of applied voltage of 80 kV, material: tin plate, size: 100 × 200 mm
The coated plate (IV) having a film thickness of 51 μm was prepared by coating the coated substrate (4) and baking at 190 ° C. for 20 minutes.

<Examples 5-8> In Examples 5-8, the metallic pigments (I) produced in Examples 1-4 were used.
The following experiment was conducted using (IV).

Acrylic thermosetting resin powder (trade name Te
odur AC 793-N, Takashi Kubo Paint Co., Ltd.
100 parts by mass) and metallic pigments (I) to (IV).
6 parts by mass and mixed to obtain a powder coating composition (V)
~ (VIII) were prepared.

Further, the powder coating compositions (V) to (VII
I) is a corona discharge type electrostatic powder coating machine (MXR-100
VT-mini, manufactured by Matsuo Sangyo Co., Ltd., under the condition of an applied voltage of 80 kV, material: tin plate, size: 100
The coated plates (V) to (VIII) having a film thickness of 55 to 78 μm were prepared by coating the substrate having a size of × 200 mm and baking at 150 ° C. for 20 minutes.

Comparative Examples 1 to 3 In Comparative Examples 1 to 3, the metallic pigments (I) prepared in Examples 1 to 4 were used.
Instead of (IV), the following commercially available methacrylic acid ester resin-coated metallic pigments (PCF7640,
The following experiments were carried out using PCF1440, PCF7160, manufactured by Toyo Aluminum Co., Ltd.

It should be noted that PCF7640, PCF1440,
The resin coating amount of PCF7160 is 13.3 g, 7.5 g, and 1 with respect to 100 g of aluminum base particles, respectively.
It is 6.5 g.

That is, in Comparative Examples 1 to 3, polyester-based thermosetting resin powder (trade name: Teodur P
E 785-900, Takashi Kubo Paint Co., Ltd.) 100
6 parts by weight of each of PCF7640, PCF1440 or PCF7160 was mixed to prepare powder coating compositions (IX) to (XI).

Further, powder coating compositions (IX) to (X
I) is a corona discharge type electrostatic powder coating machine (MXR-100
VT-mini, manufactured by Matsuo Sangyo Co., Ltd., under the condition of an applied voltage of 80 kV, material: tin plate, size: 100
By coating on a substrate having a size of × 200 mm and baking at 190 ° C. for 20 minutes, a coated plate having a film thickness of 55 to 82 μm (I
X) to (XI) were prepared.

<Comparative Examples 4 to 6> In Comparative Examples 4 to 6, as in Comparative Examples 1 to 3, instead of the metallic pigments (I) to (IV) produced in Examples 1 to 4, Commercially available methacrylic acid ester resin coated metallic pigments (PCF7640, PCF1440, PCF716
0, manufactured by Toyo Aluminum Co., Ltd., the following experiment was performed.

That is, in Comparative Examples 4 to 6, the acrylic thermosetting resin powder (trade name: Teodur AC
793-N, Takashi Kubo Paint Co., Ltd.) 100 parts by mass, and PCF7640, PCF1440 or P, respectively.
Powder coating compositions (XII) to (XIV) were produced by mixing 6 parts by weight of CF7160 with each other.

Further, powder coating compositions (XII) to (X
IV) to a corona discharge type electrostatic powder coating machine (MXR-10
0VT-mini, manufactured by Matsuo Sangyo Co., Ltd., under the condition of applied voltage of 80 kV, material: tin plate, size: 10
The coated plates (XII) to (XIV) having a film thickness of 48 to 75 μm were prepared by coating the substrate having a size of 0 × 200 mm and baking at 150 ° C. for 20 minutes.

<Characteristic Analysis and Performance Evaluation> Examples 1 to 1
8. Metallic pigment (I) produced in Comparative Examples 1 to 6
For the coating film formed on (IV) and the coated plate, the content of the fluorine-based coating film of the metallic pigment, the content of the base aluminum particles in the coating film, and the brightness of the coating film were measured based on the following test methods. Characterized or performance evaluated. The results are shown in Tables 1 and 2.

(I) Method for measuring the content of the fluorine-based coating of the metallic pigment The measurement was carried out using the gravimetric method (acid-dissolving gravimetric method).

Specifically, after weighing the sample, the aluminum component was dissolved with an acid, and then the acid was removed by filtration.
The residual fluorine-based coating resin was thoroughly washed with pure water and then dried, and its weight was measured.

(Ii) Measurement of Content of Substrate Aluminum Particles in Coating Film The measurement was carried out using the gravimetric method (NMP dissolution weight method).

Specifically, at the time of coating, a plurality of coated plates were coated at the same time, one of them was not baked, and the coating material adhering to the surface was scraped off to obtain a powder sample. Then, the sample before baking was analyzed and used as the aluminum content of the other baked coating film. This is because the aluminum content does not change due to baking.

As a method of analyzing the powdery sample, after weighing the powdery sample, N-methylpyrrolidone (NM
P) to dissolve the thermosetting resin component, then NMP by filtration
Was removed, and the remaining base aluminum particles (resin-containing coating) were thoroughly washed with pure water and dried, and the weight was measured. Since the fluorine-based resin coating does not dissolve in NMP, the content of the fluorine-based coating measured by the above method is used to convert the base aluminum particle content.

(Iii) Evaluation Method of Brightness of Coating Film First, a gonio-colorimeter (“X-Rite” manufactured by X-Rite).
MA-68 ") observation angle θ is 15 degrees, 25 degrees, 45
The measured L value of the coating film formed on the coated plate was measured at 100, 75, and 110 degrees. Next, the value of β / α was calculated from the measured values based on the following formula (1) to evaluate the brightness of the coating film. The larger β / α, the better the sense of brightness. L = [β / (θ ² + α)] + γ ... Equation (1) In the equation (1), L is a spectrophotometer (trade name “X
-Rite MA68 "manufactured by X-Rite Co., Ltd., the lightness index (L ^* a ^* b ^* colorimetric system, which is a colorimetric system based on the uniform color space defined by 1976 by CIE). , Θ are observation angles, and α, β and γ are constants.

Here, for the calculation of β / α, it is first necessary to determine α, β and γ. That is, first, the observation angle θ is 15 degrees, 25 degrees, 45 degrees, 75 degrees and 110 degrees.
Measured L value in degrees, and assuming that the relationship between θ and L value is in accordance with equation (1), α by the least squares method,
Determine β and γ.

In addition, Table 1 and Table 2 show the above (i)
In addition to the evaluation items from (iii) to (iii), the trade names and average particle diameters (D50) of the base aluminum particles used in Examples 1 to 8 and Comparative Examples 1 to 6 and the resin composition constituting the metallic pigment coating film The type of resin contained in the above, the type of raw material monomer of the resin, the type of thermosetting resin powder used in the powder coating composition, and the like are also shown.

In Tables 1 and 2, the content of aluminum in the coating film is represented only by the amount of metallic aluminum less the amount of the resin composition constituting the coating of the metallic pigment.

Then, in * 1 of Table 1 and Table 2,
The resin coating amount of the metallic pigment is expressed in parts by mass of the resin based on 100 parts by mass of the aluminum base particles.

Further, commercially available methacrylic acid ester resin-coated metallic pigments (PCF7640, PCF1)
440, PCF7160, manufactured by Toyo Aluminum Co., Ltd.
The content of the methacrylic acid ester-based resin contained in the resin composition forming the coating film is obtained from the product data of Toyo Aluminum Co., Ltd., which is a manufacturer of these products.

[0153]

[Table 1]

[0154]

[Table 2]

From the results shown in Table 1 and Table 2, Example 1
In all cases of 8 to 8, the brightness feeling of the coating film using the powder coating composition containing the metallic pigment of the present invention is irrespective of the average particle size of the base aluminum particles used and the type of the thermosetting resin powder. It can be seen that the brightness is clearly higher than that of the coating film using the powder coating composition containing the conventional resin-coated metallic pigments shown in Comparative Examples 1 to 6.

In general, the β / α value, which is an evaluation parameter of the brightness, increases as the aluminum content in the coating film increases, but the results of Table 1 and Table 2 show that
It can be seen that the above difference in brightness is not caused by the difference in aluminum content in the coating film.

Therefore, it is understood that the above difference in brightness is caused by the difference in the resin composition forming the coating film that coats the aluminum particles on the substrate.

The embodiments and examples disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0159]

From the above results, the metallic pigment of the present invention can be preferably used in a powder coating composition,
In addition, it can be said that it is a metallic pigment that gives the coating film an excellent metallic feeling and high brightness feeling.

It can be said that the coating composition of the present invention is a coating composition containing the metallic pigment of the present invention and giving a coating film an excellent metallic feeling and high brightness feeling. Similarly, it can be said that the powder coating composition of the present invention is a powder coating composition containing the metallic pigment of the present invention and imparting an excellent metallic feeling and high brightness feeling to the coating film.

Furthermore, the coating film of the present invention is a coating film of the coating composition of the present invention or the powder coating composition of the present invention, and can be said to be a coating film having excellent metallic feeling and high brightness feeling. .

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between an observation angle by a spectrophotometer and a measured value of L value of a coating film.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 201/00 C09D 201/00 F term (reference) 4J037 AA24 CC14 EE03 EE04 FF03 4J038 HA066 KA15 MA02 NA01

Claims (9)

[Claims] 1. A metallic pigment comprising aluminum particles as base particles and a single-layer or multi-layer coating for coating the surface of the aluminum particles, wherein at least one of the single-layer or multi-layer coating is a molecule. A metallic pigment comprising a resin composition containing a fluororesin having a fluorinated alkyl group therein. 2. With respect to 100 parts by mass of aluminum particles,
The metallic pigment according to claim 1, wherein the content of the coating film made of the resin composition containing the fluororesin is in the range of 0.1 to 50 parts by mass. 3. The fluororesin is a homopolymerization or copolymerization of acrylic acid and / or methacrylic acid ester of a fluorinated alkyl alcohol in which a part or all of hydrogen atoms of a C1 to C20 alkyl alcohol are substituted with fluorine atoms. The metallic pigment according to claim 1 or 2, which is a resin obtained by the above. 4. The fluororesin is a resin obtained by homopolymerizing or copolymerizing trifluoroethyl methacrylate and / or perfluorooctylethyl acrylate, according to any one of claims 1 to 3. Metallic pigment. 5. A coating composition containing the metallic pigment according to claim 1 and a binder. 6. A powder coating composition containing the metallic pigment according to claim 1 and a thermosetting resin powder. 7. The powder coating composition according to claim 6, wherein the thermosetting resin powder contains an acrylic resin or a polyester resin. 8. The powder coating composition according to claim 6, which contains 1 to 40 parts by mass of the metallic pigment with respect to 100 parts by mass of the thermosetting resin powder. 9. A coating film formed from the powder coating composition according to claim 6, wherein the L value and the observation angle (θ) by an L ^* a ^* b ^* colorimetric system. The coating film is characterized in that the value of β / α is 180 or more when the correlation of is approximated by the following formula L = [β / (θ ² + α)] + γ.