JP2022163850A - Composite metal pigment composition and method for manufacturing the same - Google Patents

Abstract

To provide a composite metal pigment composition having a high nonvolatile (solid) content, excellent in dispersibility in a coating material, especially water based paint, capable of forming a coating film excellent in color tone, brightness, concealability, etc., capable of obtaining a coating material, especially water based paint excellent even in storage stability and capable of balancing these characteristics at a high level, and a method for manufacturing the same.SOLUTION: In a composite metal pigment composition including metal particles and composite particles including a metal oxide coating formed on the surface of the metal particle, (1) the shape of the composite particle is scaly; (2) when measuring the particle size distribution of the composite particles by a laser diffraction particle size distribution meter, a volume based average particle size D50 is 1-30 μm; (3) the average particle thickness of the composite particles is 20-300 nm; (4) the solid content concentration of the composite metal pigment composition is 70-95 mass%; (5) a hydrophilic solvent having a boiling point of 80-150°C occupies 80 mass% or more of the non-solid content of the composite metal pigment composition; and (6) when filtering the composite metal pigment composition by a filter of 200 meshes, a residue is 0.1 mass% or less of the solid content.SELECTED DRAWING: None

Description

The present invention relates to a composite metal pigment composition comprising metal particles and composite particles having a metal oxide coating formed on the surface thereof and a method for producing the same, and more specifically to a volatile organic compound (VOC) content. while reducing the agglomeration, deformation, etc. of the composite particles effectively, low VOC, storage stability when used for water-based paint, etc. Excellent coating film such as suppression of pimples, design properties, hiding properties The present invention relates to a composite metal pigment composition having highly balanced properties and the like, and a method for producing the same.

BACKGROUND ART Conventionally, metallic pigments have been used for metallic paints, printing inks, kneading into plastics, and the like, for the purpose of obtaining a cosmetic effect that emphasizes a metallic feeling.
In recent years, in the field of coatings, there is an increasing need to switch to water-based coatings that use less organic solvents in order to conserve resources, improve working environments, and eliminate pollution. In order to improve the stability of metal pigments in water-based paints, pigments using composite particles in which metal particles are coated with a metal oxide such as amorphous silica have been proposed. Even in such water-based paints, further VOC reduction is required. In order to reduce VOCs, it is effective to improve the non-volatile (solid) content in the manufacturing process. The metal particles may be deformed or agglomerated, and defects may occur in the metal oxide coating such as silica, resulting in deterioration of water resistance and storage stability. In addition, it is possible to improve the non-volatile content by volatilizing the solvent by heating or reducing pressure, but in this case the surface dries early and the particles adhere and aggregate to each other, dispersing in the solvent or water without aggregation. I can't do it. As described above, the composite metal pigment composition improved in non-volatile content by the conventional method has problems such as poor dispersibility at the time of coating preparation, inability to express the desired color tone, poor storage stability, and the like. There was a strong demand for its solution.

For example, US Pat. No. 6,000,000 describes providing PVD metallic effect pigments which are present in the form of powders or in highly concentrated form, and that the PVD pigment powders should be substantially free of agglomeration, exhibiting good redispersion performance. It states that it should have However, aggregation after redispersion has not been directly evaluated, and dispersibility in an aqueous solvent has not been reported.
US Pat. No. 6,200,400 describes suction filtration through a Buchner funnel in the preparation of coated aluminum effect pigments and describes the use of the aluminum effect pigments to form water-based paint systems, although dispersion Sexuality was not reported.

Japanese Patent Application Publication No. 2017-533982 Japanese Patent Application Publication No. 2013-518948

In view of the above limitations of the prior art, an object of the present invention is to provide a composite metal pigment composition having a high non-volatile (solid) content, which is excellent in dispersibility in paints, especially water-based paints, and has color tone, brightness, and hiding properties. It is possible to form a coating film excellent in such as, and to obtain a paint excellent in storage stability, especially a water-based paint. to provide.

As a result of intensive research, the present inventors have found that a specific hydrophilic solvent is used as the solvent that constitutes the composite metal pigment composition, and/or the solvent is volatilized under specific conditions in the production of the composite metal pigment composition. Therefore, the inventors have found that the above objects can be achieved, and have completed the present invention.

That is, the first invention of the present application and various aspects thereof are as follows.
[1]
A composite metal pigment composition comprising composite particles having a metal particle and a metal oxide coating formed on the surface thereof,
(1) the shape of the composite particles is scaly,
(2) the volume-based average particle diameter _D50 when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter is 1 to 30 μm;
(3) the composite particles have an average particle thickness of 20 to 300 nm,
(4) the composite metal pigment composition has a solid content concentration of 70 to 95% by mass;
(5) a hydrophilic solvent having a boiling point of 80 to 150° C. accounts for 80% by mass or more of the non-solid content of the composite metal pigment composition;
(6) The above-mentioned composite metal pigment composition, wherein the residue when the composite metal pigment composition is filtered through a 200-mesh filter is 0.1% by mass or less of the solid content.
[2]
The composite metal pigment composition according to [1], wherein the proportion of non-aggregated primary particles in the composite particles is 35% or more on a number basis.
[3]
The composite metal pigment composition according to [1] or [2], wherein the proportion of bent composite particles in the composite particles is 10% or less on a number basis.
[4]
The composite metal pigment composition according to any one of [1] to [3], wherein at least one layer in the metal oxide coating is a silicon compound-containing layer.
[5]
The composite metal pigment composition according to any one of [1] to [4], wherein the metal oxide coating has an average layer thickness of 5 to 200 nm.
[6]
The composite metal pigment composition according to any one of [1] to [5], wherein the metal particles contain aluminum or an aluminum alloy.
[7]
The composite metal pigment according to any one of [1] to [6], wherein the composite particles further have a coating layer containing at least one selected from metals, metal oxides, metal hydrates and resins. Composition.

In addition, the second and third inventions of the present application and aspects thereof are as follows.
[8]
A method for producing a composite metal pigment composition comprising the following steps 1) to 3),
1) a step of dispersing metal particles in a solvent; 2) a step of coating the metal particles with a metal oxide; The solvent in the step of washing, filtering, and volatilizing the solvent step 3) is a mixed solvent of two or more solvents that are compatible with each other and have a boiling point difference of 10 ° C. or more,
The above manufacturing method, wherein the solvent volatilization in step 3) is performed in a slurry state containing the composite particles and the solvent.
[9]
A method for producing a composite metal pigment composition comprising the following steps 1) to 3),
1) a step of dispersing metal particles in a solvent; 2) a step of coating the metal particles with a metal oxide; Washing, Filtration, and Solvent Volatilization Process The above manufacturing method, wherein the solvent volatilization in step 3) is divided into three or more steps.
[10]
The production method according to [8] or [9], wherein the solvent has a moisture content of 10% by mass or less when the solvent is volatilized in step 3).

According to the present invention, it is possible to obtain a novel composite metal pigment composition not found in prior art.
The composite metal pigment composition of the first invention of the present application effectively suppresses aggregation, deformation, etc. of composite particles while reducing the amount of volatile organic compounds (VOC). It is possible to balance excellent properties of the coating film such as storage stability, suppression of pimples, designability, concealability, etc. at a high level beyond the limits of the prior art.
According to the production methods of the second and third inventions of the present application, while reducing the amount of volatile organic compounds (VOC), the aggregation, deformation, etc. of the composite particles are effectively suppressed, and used in low-VOC, water-based paints, etc. It is possible to efficiently produce a composite metal pigment composition in which the excellent properties of the coating film such as storage stability, suppression of pimples, design properties, hiding properties, etc. are well balanced at a high level beyond the limits of conventional technology. can.

The present invention will be described below along typical or preferred embodiments, but the present invention is not limited to these embodiments. Unless explicitly indicated, these embodiments are freely combinable within the scope of the invention as defined in the appended claims.

A first invention of the present application is a composite metal pigment composition comprising metal particles and composite particles having a metal oxide coating formed on the surface thereof,
(1) the shape of the composite particles is scaly,
(2) the volume-based average particle diameter _D50 when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter is 1 to 30 μm;
(3) the composite particles have an average particle thickness of 20 to 300 nm,
(4) the composite metal pigment composition has a solid content concentration of 70 to 95% by mass;
(5) a hydrophilic solvent having a boiling point of 80 to 150° C. accounts for 80% by mass or more of the non-solid content of the composite metal pigment composition;
(6) The above-mentioned composite metal pigment composition, wherein the residue when filtered through a 200-mesh filter is 0.1% by mass or less of the solid content.

Composite Particles Constituting the Composite Metal Pigment Composition The composite metal pigment composition according to the first invention of the present application comprises composite particles having metal particles and a metal oxide coating formed on the surface thereof.
That is, the term "composite metal pigment composition" as used herein contains, as essential components, metal particles and composite particles having a metal oxide coating formed on the surface thereof, and further contains a specific non-solid content.
The composite metal pigment composition according to the first invention of the present application may contain other components such as an organic treating agent, water and/or a solvent including a hydrophilic solvent.

Metal Particles The composite particles constituting the composite metal pigment composition according to the first invention of the present application comprise metal particles and a metal oxide coating formed on the surface thereof. That is, one or more layers of metal oxide coating are formed on the surface of the metal particles serving as the core of the composite particles. Metal oxide coatings usually have a layered structure.

The material of the metal particles (core particles) that make up the composite particles is not particularly limited. Alternatively, any metal used as a commercially available metal pigment may be used. In this specification, the metal of the metal particles constituting the composite particles includes not only simple metals but also alloys and intermetallic compounds.
Metal particles may be used singly or in combination of two or more.
The metal particles in the first invention of the present application preferably contain aluminum or an aluminum alloy, more preferably 95% by mass or more of the aluminum element.

The average particle size of the metal particles is not particularly limited, but it is preferably an average particle size that can provide _D50 in the particle size distribution of the composite particles described later. That is, the volume average particle diameter of the metal _particles ( _D50 ) is preferably set.
The average particle diameter of the metal particles is determined by the process of grinding, sieving, and filtering raw material atomized metal powder (e.g., aluminum powder) using a ball mill or the like. It can be controlled by appropriately adjusting the mass of each crushing ball, the number of revolutions of the crushing device, the degree of sieving and filter pressing, and the like.

Although the thickness and shape of the metal particles are not particularly limited, it is desirable that the metal particles are scale-like (flake-like) with an average particle thickness of 10 to 300 nm. As a result, the composite particles constituting the composite metal pigment composition according to the first invention of the present application can easily have a scaly shape, and as a result, high hiding power and the like can be obtained more reliably.
The average thickness of the metal particles is preferably such that the average thickness of the composite particles described later can be achieved, specifically preferably 10 to 300 nm. As a result, the aggregation and deformation of the composite particles are effectively suppressed, and it becomes easy to achieve excellent design properties, gloss, suppression of pimples, stability in water-based paint, and the like in the coating film. From the above viewpoint, the average thickness of the metal particles is preferably 15 to 250 nm, more preferably 20 to 200 nm.

Here, the average particle thickness of the metal particles can be measured by a method known in the art, for example, using a metal pigment composition comprising composite particles having metal particles and a metal oxide coating on the surface thereof. It can be measured by forming a coating film, acquiring an FE-SEM image (field emission scanning electron microscope image) of the cross section, and analyzing the image. More specifically, it can be measured by the method described in the Examples of the present application.

The aspect ratio (shape factor obtained by dividing the average particle diameter by the average thickness) of the scaly metal particles is preferably 30 to 1500, more preferably 50 to 1000, particularly 80 to 700. preferable. When the aspect ratio of the metal particles is 30 or more, a higher feeling of brightness can be obtained. Moreover, when the aspect ratio of the metal particles is 1500 or less, the mechanical strength of the flakes is maintained, and a stable color tone can be obtained.
The average thickness of the metal particles is the same as the volume-based _D50 , in the process of grinding, sieving, and filtering the raw atomized metal powder (for example, aluminum powder) using a ball mill or the like. can be controlled by appropriately adjusting the mass per grinding ball, the number of revolutions of the grinding device, the degree of sieving and filter pressing, etc., when using .

In addition, the metal particles do not necessarily have to be composed only of metal, and as long as the effects of the first invention of the present application are not hindered, the surfaces of inorganic particles such as synthetic resin particles, mica, glass, etc., are coated with metal. Particles and the like can also be used. In the first invention of the present application, particles containing aluminum or an aluminum alloy are desirable in terms of particularly high weather resistance, low specific gravity, easy availability, and the like.

Aluminum flakes, which are commonly used as metallic pigments, are particularly suitable as the metal particles constituting the composite particles. As the aluminum flakes, those having surface properties such as surface glossiness, whiteness, luster, etc., particle size, and shape required for metallic pigments are suitable. Aluminum flakes are usually commercially available in paste form. The paste-like aluminum flakes may be used as they are, or may be used after removing the fatty acid or the like from the surface in advance with an organic solvent or the like. Also, a so-called aluminum evaporated foil having a volume average particle size (D ₅₀ ) of 3 to 20 μm and an average thickness (t) of 10 to 110 nm can be used.

Metal Oxide Coating The composite particles constituting the composite metal pigment composition of the first invention of the present application have a metal oxide coating formed on the surface of the metal particles.
The metal oxide coating is a film composed of a layer containing metal oxide, and may be formed on the entire surface of the metal particles or may be formed only on a part of the surface. From the viewpoint of water resistance and storage stability when used in paint, it is preferably formed on the front surface.
The metal oxide coating may be composed entirely of metal oxide, or may be partially composed of metal oxide and may contain components other than metal oxide.

The metal oxide forming the metal oxide coating is a compound containing oxygen and at least one metal element as constituent elements.
Therefore, the metal oxide may be a narrowly defined metal oxide having only oxygen and at least one metal element as its constituent elements, but as long as it contains oxygen and at least one metal element as its constituent elements, Elements other than the oxygen and metal elements may be included in the constituent elements, such as metal hydroxides, oxide hydrates, and oxynitrides. It may also be a compound containing an organic group.
The metal oxide may be a so-called single oxide containing only one metal element as a constituent element, or a composite oxide containing two or more metal elements as constituent elements.
At least one metal element constituting the metal oxide may be a typical metal or a transition metal. Furthermore, it may be a so-called metalloid element. Among them, a metal oxide containing silicon as a constituent element is particularly suitable as a metal oxide constituting the metal oxide coating.

Specific examples of suitable metal oxides constituting the metal oxide coating include silicon oxide, aluminum oxide, boron oxide, zirconium oxide, cerium oxide, iron oxide, titanium oxide, chromium oxide, tin oxide, molybdenum oxide, vanadium oxide, Their oxide hydrates, their hydroxides, mixtures thereof and the like can be mentioned. Among them, silicon oxide, aluminum oxide, mixtures thereof, and oxide hydrates and hydroxides thereof are preferably used. Particularly preferably, silicon oxides such as silicon oxide, silicon hydroxide and/or silicon oxide hydrates can be used.

The use of silicon oxide for the metal oxide coating is particularly effective from the viewpoint of realizing good storage stability in water-based paint, improving water resistance when it is made into a coating film, and suppressing gas generation. Advantageous.
By using silicon oxide for the metal oxide coating, the metal oxide coating is usually a layer composed of compounds containing Si—O—bonds (siloxane bonds). Examples of such a layer include a layer containing at least one of a silane compound and silicon oxide. Examples of such compounds include silane-based compounds [H ₃ SiO(H ₂ SiO) _n SiH ₃ ] (where n represents an arbitrary positive integer), SiO ₂ , SiO ₂ ·nH ₂ O ( However, n represents any positive integer.) and the like are exemplified. These silane-based compounds and silicon oxides may be either crystalline or amorphous, but are preferably amorphous. Therefore, as the layer containing silicon oxide (silica etc.), for example, a layer containing amorphous silica can also be suitably employed.

Also, the metal oxide coating using silicon oxide may be a layer formed using an organosilicon compound (including a silane coupling agent) as a starting material. In this case, the metal oxide coating may contain an unreacted organosilicon compound or a component derived therefrom within a range that does not impair the effects of the first invention of the present application. Typically in this case, the metal oxide coating can be formed by hydrolyzing an organosilicon compound.

The mass of the metal oxide coating layer when silicon oxide is used is not particularly limited, but it is preferably 1 to 20 parts by mass, particularly 2 to 15 parts by mass with respect to 100 parts by mass of the metal particles. more preferred. When the silicon content of the metal oxide coating is 1 part by mass or more with respect to 100 parts by mass of the metal particles, the composite metal pigment composition can maintain high corrosion resistance, water dispersibility, stability, and the like. When the silicon content of the metal oxide coating is 20 parts by mass or less with respect to 100 parts by mass of the metal particles, it is possible to prevent aggregation of the composite particles and deterioration of color tone such as hiding property and metallic luster.

The metal oxide coating of the composite particles contained in the composite metal pigment composition according to the first invention of the present application is particularly preferably hydrophilic. The composite particles usually form a composite metal pigment composition dispersed in an aqueous solvent (water or a mixed solvent containing water and an organic solvent). When the metal oxide coating has a hydrophilic surface, The composite particles can be highly dispersed in such aqueous solvents. Moreover, since metal oxides such as silicon oxide (amorphous silica, etc.) are very stable in aqueous solvents, it is possible to provide composite metal pigments containing composite particles that are highly stable in aqueous solvents. . From this point of view, in the composite particles contained in the composite metal pigment composition according to the first invention of the present application, at least one layer, preferably the outermost layer, is desirably a metal oxide film, and a silicon compound-containing layer (especially Si- A layer composed of a compound containing an O-bond) is particularly desirable. Since the metal oxide has excellent affinity with the metal particles, when the composite particles have a coating layer composed of a plurality of layers, in addition to the metal oxide coating of the outermost layer, a layer other than the outermost layer, particularly preferably a metal As a layer in contact with the particles, a metal oxide layer, particularly preferably a silicon compound-containing layer (especially a Si—O-based coating layer) may be separately formed.

The thickness of the metal oxide coating of individual composite particles is not particularly limited as long as the average particle thickness of the composite particles is in the range of 20 to 300 nm, as described later. It is desirable that the thickness of the metal oxide coating is usually in the range of about 5 to 200 nm (especially 10 to 100 nm, further 20 to 70 nm). When the thickness of the metal oxide coating is 5 nm or more, it is possible to obtain a coating film that has sufficient water resistance and suppresses the occurrence of corrosion or discoloration of metal particles in water-based paint. On the other hand, when the thickness of the metal oxide coating is about 200 nm or less, the brightness, sharpness and hiding power of the coating film can be maintained at a high level.

When the metal oxide coating of individual composite particles includes a silicon compound-containing layer, the thickness of the silicon compound-containing layer is not particularly limited as long as the average thickness of the composite particles is in the range of 2 to 300 nm, as described later. . The thickness of the silicon compound-containing layer may generally be in the range of 5 to 200 nm, particularly preferably in the range of 10 to 100 nm, and further in the range of 20 to 70 nm, from the viewpoint of the function of the layer. is preferred.

Specific examples of the organosilicon compound that can be used in the present embodiment are further described below, but the organosilicon compound is not limited to these specific examples.
The organosilicon compound is a so-called silane coupling agent represented by at least one organosilicon compound represented by the following general formula (1) and any one of the following general formulas (2), (3) and (4). , and at least one selected from partial condensates thereof.

Si(OR ¹ ) ₄ (1)
(In the formula, R ¹ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and when there are two or more R ¹ s, they may all be the same, some may be the same, or all may be different. is also good.)
R ² _m Si(OR ³ ) _4-m (2)
(Wherein, R ² is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may optionally contain a halogen group, and R ³ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms R ² and R ³ may be the same or different, and when there are two or more R ² or R ³ , all of them may be the same, some of them may be the same, or all of them may be different. 1≤m≤3.)
R ⁴ _p R ⁵ _q Si(OR ⁶ ) _4-pq (3)
(In the formula, R ⁴ is a group containing a reactive group capable of chemically bonding with other functional groups, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, which may optionally contain a halogen group. and R ⁶ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms.When there are two or more R ⁴ , R ⁵ , or R ⁶ , all or part of , all may be different, 1 ≤ p ≤ 3, 0 ≤ q ≤ 2, 1 ≤ p + q ≤ 3.)
R7rSiCl4 ^- _r ... ( ₄ )
(In the formula, R ⁷ is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may optionally contain a halogen group, and when there are two or more R ⁷ , even if all are the same, some may be the same or all may be different, 0≦r≦3.)

Examples of hydrocarbon groups for R ¹ in formula (1) include methyl, ethyl, propyl, butyl, hexyl, octyl, etc., which may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl and butyl are particularly preferred. In addition, all four R ¹ 's may be the same, some may be the same, or all may be different.
Preferred examples of such organosilicon compounds of formula (1) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and the like. Among these, tetraethoxysilane is particularly preferred.

Examples of hydrocarbon groups for R ² in formula (2) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, naphthyl, etc., which are It may be branched or linear, and may contain halogen groups such as fluorine, chlorine, and bromine. Among these, hydrocarbon groups having 1 to 18 carbon atoms are particularly preferred. Moreover, when there are two or more R ² , they may all be the same, some of them may be the same, or all of them may be different. The number of R ² in the molecule is m=1 to 3, that is, 1 to 3 in formula (2), but m=1 or 2 is more preferable.
Examples of hydrocarbon groups for R ³ in formula (2) include methyl, ethyl, propyl, butyl, hexyl, octyl, etc., which may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl and butyl are particularly preferred. Moreover, when there are ^two or more R3's, they may all be the same, some of them may be the same, or all of them may be different.
Preferred examples of such organosilicon compounds (silane coupling agents) of formula (2) include methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, silane, trimethylmethoxysilane, trimethylethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltributoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltributoxysilane, dibutyldimethoxysilane, Dibutyldiethoxysilane, dibutyldibutoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dioctyl Dimethoxysilane, dioctyldiethoxysilane, dioctylethoxybutoxysilane, decyltrimethoxysilane, decyltriethoxysilane, didecyldimethoxysilane, didecyldiethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, dioctadecyldimethoxysilane, di Octadecyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trifluoropropyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluoro octyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropyltributoxysilane and the like.

Examples of reactive groups that can chemically bond with other functional groups in R ⁴ of formula (3) include vinyl groups, epoxy groups, styryl groups, methacryloxy groups, acryloxy groups, amino groups, ureido groups, mercapto groups, and polysulfide groups. , an isocyanate group, and the like.
Moreover, when there are two or more ^R4 's, they may all be the same, some of them may be the same, or all of them may be different. The number of ^R4 's in the molecule is p=1 to 3, that is, 1 to 3 in formula (3), but p=1 is more preferable.
Examples of hydrocarbon groups for R ⁵ in formula (3) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, naphthyl and the like, which are It may be branched or linear, and may contain halogen groups such as fluorine, chlorine, and bromine. Among these, hydrocarbon groups having 1 to 18 carbon atoms are particularly preferred. Moreover, when there are two or more R ⁵ , they may all be the same, some of them may be the same, or all of them may be different.
Examples of hydrocarbon groups for R ⁶ in formula (3) include methyl, ethyl, propyl, butyl, hexyl, octyl, etc., which may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl and butyl are particularly preferred. Moreover, when there are two or more R ⁶ , they may all be the same, some of them may be the same, or all of them may be different.

Preferred examples of such organosilicon compounds (silane coupling agents) of formula (3) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris(2-methoxyethoxy)silane, 2-(3,4 -epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacrylic roxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-methyl-3-amino Propyl-trimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3 -aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3- aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyl-triethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane and the like.

Examples of hydrocarbon groups for R ⁷ in formula (4) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, naphthyl, etc., which are It may be branched or linear, and may contain halogen groups such as fluorine, chlorine, and bromine. Among these, hydrocarbon groups having 1 to 12 carbon atoms are particularly preferred. Moreover, when there are two or more R ⁷ , they may all be the same, some of them may be the same, or all of them may be different. The number of ^R7 in the molecule is r=0 to 3, ie, 0 to 3 in formula (4), and more preferably r=1 to 3.
Preferred examples of such organosilicon compounds (silane coupling agents) of formula (4) include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, octyldimethylchlorosilane, phenyltrichlorosilane, vinyltrichlorosilane, tetrachlorosilane, and the like. mentioned.

The organosilicon compounds represented by the general formula (1) may be used alone or in combination of two or more. Also, the silane coupling agents represented by any of the general formulas (2), (3) and (4) may be used alone or in combination of two or more. good too. When two or more are used in combination, only the silane coupling agents represented by any one of (2), (3) and (4) may be used in combination of two or more, Silane coupling agents represented by two or more different general formulas may be used in combination.

The hydrolyzate and/or condensation reaction product of the organosilicon compound can be obtained by stirring and mixing the organosilicon compound, a necessary amount of water for the hydrolysis reaction, and a hydrolysis catalyst. In that case, a hydrophilic solvent can also be used as needed. Various conditions for the hydrolysis reaction (that is, the reaction for forming the silicon compound-containing layer) will be described later.

As raw materials for the hydrolysis reaction and/or the condensation reaction for obtaining the hydrolyzate and/or the condensation reaction product of the organosilicon compound, preliminarily partially condensed oligomers may be used.
The condensation reaction of the hydrolyzate of the organosilicon compound may be carried out simultaneously with the hydrolysis reaction of the organosilicon compound, or may be carried out in separate steps with a different catalyst if necessary. In that case, you may heat as needed.

Physical Properties of Composite Particles and Composite Metal Pigment Composition The composite particles constituting the composite metal pigment composition according to the first invention of the present application satisfy the following physical property requirements.
(1) The shape of the composite particles is scaly.
(2) The volume-based average particle diameter _D50 when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter is 1 to 30 μm.
(3) The composite particles have an average particle thickness of 20 to 300 nm.
The composite metal pigment composition according to the first invention of the present application further satisfies the following requirements as a composition.
(4) The solid content concentration of the composite metal pigment composition is 70 to 95% by mass.
(5) A hydrophilic solvent having a boiling point of 80 to 150° C. accounts for 80% by mass or more of the non-solid content of the composite metal pigment composition.
(6) The residue when the composite metal pigment composition is filtered through a 200-mesh filter is 0.1% by mass or less of the solid content.
Each of these physical property requirements will be described below.

(1) The shape of the composite particles is scaly.
The composite particles contained in the composite metal pigment composition according to the first invention of the present application are scaly in shape. By containing scale-like composite particles, the composite metal pigment composition of the first invention of the present application can effectively form a coating film having excellent properties such as high hiding power.
The scaly composite particles are easily deformed during processes such as stirring, separation, and filtration during production, and are particularly deformed by strong centrifugation to increase the non-volatile (solid) content and filtration under strong pressure. However, in the present invention, deformation of the scaly composite particles can be effectively suppressed while achieving a high non-volatile (solid) content.

Here, that the composite particles are scaly means that the particles preferably have a shape having a high aspect ratio within the numerical range described later.
The scaly composite particles can be produced by, for example, using scaly metal particles as raw materials in producing the composite particles. As such metal particles, for example, known or commercially available pasty aluminum flakes can be used.

The scale-like composite particles contained in the composite metal pigment composition according to the first invention of the present application preferably have an aspect ratio (shape factor obtained by dividing the average particle size by the average thickness) of 30-700. When the aspect ratio of the composite particles is 30 or more, it becomes easier to obtain a higher feeling of glitter. Further, when the aspect ratio of the composite particles is 700 or less, the mechanical strength of the composite particles is maintained, making it easy to obtain a stable color tone. The aspect ratio is preferably 50-600, more preferably 80-500.

(2) The volume-based average particle diameter _D50 when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter is 1 to 30 μm. The particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter. The volume-based average particle diameter D ₅₀ when measured is between 1 and 30 μm. As a result, the aggregation and deformation of the particles are effectively suppressed, and the coating film formed using the composite metal pigment composition or the water-based paint containing it has excellent design, gloss, and suppression of spots. , stability in water-based paint, etc. can be realized. This volume-based _D50 is also commonly referred to as the median diameter.
From the viewpoint of obtaining excellent design properties, gloss, suppression of pimples, stability in water-based paint, etc., the volume-based D ₅₀ when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter is preferably 2. to 25 μm, particularly preferably 3 to 20 μm.
The "composite particle" in this physical property requirement refers to an agglomerate (aggregate) when a plurality of composite particles are agglomerated and adhered.
Here, the volume-based D50 when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter refers to the particle diameter at a cumulative degree of ₅₀ % in the volume cumulative particle size distribution. The laser diffraction particle size distribution meter is not particularly limited, but "LA-300" (manufactured by HORIBA, Ltd.) or the like can be used. Hydrophilic solvents such as water, isopropanol, and methoxypropanol can be used as measurement solvents. For example, a composite metal pigment composition containing composite particles of a sample is subjected to ultrasonic dispersion for about 2 minutes as a pretreatment, and then put into a dispersion tank and after confirming that it is properly dispersed, D ₅₀ can be measured.
The volume-based _D50 of the composite particles constituting the composite metal pigment composition is obtained by, for example, grinding, sieving, and filtering the raw atomized metal powder (for example, aluminum powder) using a ball mill or the like. The particle size and amount charged, the amount of grinding solvent such as mineral spirit, the type and amount of grinding aid, the mass and input amount of each grinding ball when using a ball mill, the rotation speed of the grinding device, By adjusting the degree of sieving and filter pressing as appropriate, and in the step of coating the metal oxide coating (and other coating layers as necessary), the pH at the time of hydrolysis of raw materials such as organosilicon compounds , concentration, stirring temperature, stirring time, type of stirring device, power/degree of stirring (type and diameter of stirring blade, number of revolutions, presence/absence of external stirring, etc.), etc., can be controlled as appropriate. .
In addition, there is a tendency for the particle size to increase due to agglomeration during the metal oxide coating treatment. It is effective in preventing hypertrophy.

(3) The Composite Particles Have an Average Particle Thickness of 20 to 300 nm The average thickness of the composite particles contained in the composite metal pigment composition according to the first invention of the present application is 20 to 300 nm. As a result, together with the satisfaction of the above requirements (1) and (2), aggregation and deformation of the composite particles are effectively suppressed, and excellent design properties in the coating film, gloss, suppression of pimples, and water-based paint Stability and the like can be realized.
The average thickness of the composite particles is preferably 20 to 250 nm, more preferably 20 to 200 nm, from the above viewpoint.
The "composite particle" in this physical property requirement refers to an agglomerate (aggregate) when a plurality of composite particles are agglomerated and adhered.
The average thickness of the composite particles here can be calculated according to the following formula by measuring the average particle thickness of the metal particles and the thickness of the metal oxide coating.
Average particle thickness of composite particles = average particle thickness of metal particles + thickness of metal oxide coating x 2
The average particle thickness of the metal particles can be measured by the method described in (2) above.
The thickness of the metal oxide coating can be measured by methods known in the art, such as by STEM (Scanning Transmission Electron Microscopy). More specifically, it can be measured by the method described in the Examples of the present application.
The average thickness of the composite particles contained in the composite metal pigment composition is the same as the volume-based _D50 , the process of treating the raw metal powder, the metal oxide coating such as a silicon compound-containing layer (and other coating layers as necessary) ), pH, concentration, stirring temperature, stirring time, type of stirring device, power/degree of stirring (stirring blade type and diameter, number of revolutions, presence/absence of external stirring, etc.). In addition, there is a tendency for the particle size to increase due to agglomeration during the metal oxide coating treatment. It is effective in preventing hypertrophy.

(4) The solid content concentration of the composite metal pigment composition is 70 to 95% by mass.
The solid content concentration of the composite metal pigment composition according to the first invention of the present application is 70 to 95% by mass.
The composite metal pigment composition according to the first invention of the present application has a solid content concentration of 70 to 95% by mass, so that it is possible to form a coating film with a good appearance while achieving low VOC (volatile organic compounds). paint can be realized. More specifically, when the solid content concentration is 70% by mass or more, the content of VOCs in solvents and the like can be sufficiently reduced. A paint with a sufficiently reduced content can be realized. On the other hand, when the solid content concentration is 95% by mass or less, it is easy to uniformly disperse when forming a paint, and it is possible to effectively suppress the occurrence of lumps and the like in the paint film.
The solid content concentration is preferably 75 to 95% by mass, more preferably 80 to 95% by mass, and particularly preferably 85 to 95% by mass.

The solid content concentration of the composite metal pigment composition is the mass ratio of the solid content (nonvolatile content) contained in the composite metal pigment composition. The solid content concentration can be determined by heating a predetermined amount of the composite metal pigment composition to volatilize the volatile matter, measuring the mass, and determining the ratio of the mass to the mass before heating. More specifically, it can be measured, for example, by the method described in the Examples of the present application.

The solid content concentration of the composite metal pigment composition can be determined by filtering, volatilizing, or otherwise removing volatile matter such as the solvent used in dispersing the metal particles or forming the metal oxide film in the production of the composite metal pigment composition. , can be adjusted accordingly.
In order to achieve a high solid content concentration as specified in the first invention of the present application, it is preferable to use a low boiling point solvent that is easily removed by volatilization. Such a low boiling point solvent may not always be suitable for dispersing metal particles or forming a metal oxide film. Substitutions may be made.
It is also preferable to carry out the volatilization in stages. For example, after the volatilization, an operation of diffusing the composite particles in the solvent may be performed, and the volatilization may be carried out again.
Furthermore, in order to achieve a high solid content concentration, it is also preferable to combine filtration and volatilization, and it is particularly preferable to perform volatilization after filtering to reduce the amount of volatile matter.
A high solid content concentration can also be achieved by removing solvents and the like by centrifugation or relatively strong pressure filtration, but such operations aggregate and/or deform the scale-like composite particles, It should be noted that other requirements of the first invention of the present application, such as a predetermined volume-based average particle diameter _D50 and a predetermined residue amount, may be difficult to achieve.
In order to achieve the solid content concentration specified in the first invention of the present application, the volatile matter can be sufficiently removed while effectively preventing aggregation and deformation of the composite particles, so the second invention and / or the third invention of the present application It is particularly preferable to adopt the manufacturing method of

(5) 80% by mass or more of the non-solid content of the composite metal pigment composition is occupied by a hydrophilic solvent having a boiling point of 80 to 150° C. The non-solid content of the composite metal pigment composition according to the first invention of the present application is At least 80% by mass is occupied by a hydrophilic solvent having a boiling point of 80 to 150° C. (hereinafter also referred to as “specific solvent”).
Since the specific solvent has a boiling point of 80 to 150 ° C., it is easily volatilized, and extremely high temperature or reduced pressure is not required for volatilization. The solids content can be improved by removing non-solids, such as solvents.
In addition, since the specific solvent is hydrophilic, when the specific solvent accounts for 80% by mass of the non-solid content, it becomes easy to disperse the composite metal pigment composition according to the first invention of the present application in water, forming a uniform water-based paint. It becomes easier to do. In addition, by being hydrophilic, water in the composition can be more easily removed by azeotropy or the like, and aggregation caused by water can be more effectively suppressed.
The concept of a hydrophilic solvent is commonly understood among those skilled in the art. For example, a solvent having a solubility in water of 20 g/g or more at room temperature can be preferably used as a hydrophilic solvent. Also, a solvent having an sp value (solubility parameter) of 10.5 or more can be preferably used as a hydrophilic solvent.

The specific solvent preferably accounts for 80 to 100% by mass of the non-solid content of the composite metal pigment composition, more preferably 85 to 100% by mass, and particularly preferably 90 to 100% by mass.
The amount (proportion) of the specific solvent can be appropriately adjusted by adjusting the composition of the solvent used for producing the composite metal pigment composition. It is usually possible to calculate from the amount (proportion) of the specific solvent, the amount of various solvents used in the production of the composite metal pigment composition, and the amount of various solvents removed, but filtration, volatilization, etc. during production If the process is complicated and difficult to calculate, extract the solvent from the obtained composite metal pigment composition with a solvent such as THF (tetrahydrofuran) and measure by LC-MS (liquid chromatography mass spectrometer) or the like. can do.

Suitable examples of specific solvents include methoxypropanol, isobutanol, normal butanol, isopropanol, normal propanol and the like.
Only one type of these specific solvents may be used, or two or more types may be used in combination.

(6) The residue when the composite metal pigment composition is filtered through a 200-mesh filter is 0.1% by mass or less of the solid content.
The residue when the composite metal pigment composition according to the first invention of the present application is filtered through a 200-mesh filter is 0.1% by mass or less of the solid content.
Since the opening of a 200-mesh filter is about 74 μm, composite particles having a volume-based average particle diameter D ₅₀ of 1 to 30 μm and an average particle thickness of 20 to 300 nm, if there is no adhesion or agglomeration between particles, Most of it passes through a 200 mesh filter. Therefore, when the composite metal pigment composition is filtered through a 200-mesh filter, the residue is composite particles in which the particles are adhered and agglomerated, and the percentage of the solid content is preferably low.
The composite metal pigment composition according to the first invention of the present application has a residue of 0.1 mass% or less of the solid content when filtered through a 200-mesh filter. It is possible to form a paint with suppressed aggregation by dispersing it in water or water, and it is also possible to form a coating film with excellent appearance such as effectively suppressing lumps.
The amount of residue when filtered through a 200-mesh filter is preferably 0.05% by mass or less, more preferably 0.01% by mass or less, and 0.005% by mass or less of the solid content. is particularly preferred.

The amount of residue when filtered through a 200-mesh filter was determined by, after well dispersing the composite metal pigment composition in a solvent, filtering through a 200-mesh filter and measuring the dry mass of the residue. The ratio of the residue to the solid content can be determined from the mass of the solid content in the metal pigment composition. More specifically, it can be measured, for example, by the method described in Examples of the present application.
The amount of residue when filtered through a 200-mesh filter can be reduced by suppressing adhesion and agglomeration of composite particles by various techniques described herein. In particular, using a large amount of the specific solvent is effective in reducing the amount of residue. In addition, it is also effective to reduce the amount of residue by adopting the production method of the second invention and/or the third invention of the present application to effectively prevent aggregation and deformation of the composite particles while removing the volatile matter. .

Preferred physical properties, etc. of composite particles In the composite metal pigment composition according to the first invention of the present application, the composite particles constituting the composition have the following physical properties and characteristics in addition to the physical property requirements (1) to (3) above. It is preferable to have some or all of the like.

The proportion of primary particles free from agglomeration in the composite particles is 35% or more on a number basis. The proportion of particles is preferably 35% or more based on number. A ratio of primary particles of 35% or more means that the cohesiveness of individual particles is suppressed, and the degree of cohesion of not only primary particles but also aggregated particles becomes smaller. As a result, the coating film formed using the composite metal pigment composition exhibits excellent design properties, gloss, and suppression of spots, and it becomes easier to improve the stability and the like in water-based coatings.
In addition, since the agglomeration of individual particles is suppressed in this way, only mild stirring is sufficient for dispersion, and deformation of the particles due to stirring can be greatly reduced.

From the viewpoint of promoting the above effects, the proportion of non-aggregated primary particles in aggregates of composite particles is more preferably 40% or more, particularly preferably 50% or more, based on number.
The ratio of non-aggregated primary particles in the composite particles is generally preferably as high as possible, and there is no particular upper limit, and the ratio is ideally 100%.
The ratio of primary particles without agglomeration to the composite particles can be measured by a method known in the art. By forming a coating film using a material and obtaining an FE-SEM image (field emission scanning electron microscope image) of the cross section and analyzing the image, or by an evaluator with the primary particles in the FE-SEM image It can be measured by counting the number of aggregated particles. More specifically, it can be measured, for example, by the method described in Examples of the present application.

The proportion of non-aggregated primary particles in the composite particles can be improved by, for example, increasing the amount of the specific solvent used, adopting the production method of the second invention and/or the third invention of the present application, and the like. can.
Moreover, it can be controlled by appropriately setting the selection and treatment of the metal particles constituting the composite particles, the type of the metal oxide coating formed on the metal particles, and the manufacturing conditions. As an existing technique, an attempt has been made to strengthen the mechanical dispersion by increasing the rotation speed of stirring during the coating process and setting the Reynolds number to a certain value or more. There is a limit to how fine particles can be dispersed, and the problem is that thin scale-like particles are broken or deformed by strong stress during stirring.
On the other hand, it is possible to suppress agglomeration of particles during the coating treatment by pre-treating the metal particles to improve their dispersibility before coating the metal particles with the metal oxide. can significantly increase the proportion of primary particles without agglomeration.
For example, when the raw material metal particles are dispersed in a solvent and supplied, the solvent may be replaced with the same solvent as used in the coating treatment, and if desired, a heating treatment may be performed for a certain period of time. Agglomeration that occurs during the coating process can be greatly suppressed by allowing the solvent to sufficiently penetrate the surface of the metal particles. Furthermore, addition of a small amount of surfactant at this time is also effective in suppressing aggregation.

Since these treatments improve the dispersibility of the metal particles themselves, there is no need for excessive stirring during the coating treatment, and primary particles can be produced without agglomeration even with mild stirring. For this reason, it is possible to greatly reduce the deformation of the particles during the coating process, and it becomes easy to realize excellent design properties, gloss, suppression of pimples, stability in water-based paint, etc. in the coating film.

In addition to the above, as a factor that affects the ratio of primary particles without agglomeration, the raw atomized metal powder in the process of grinding, sieving, and filtering the raw atomized metal powder (e.g., aluminum powder) using a ball mill or the like etc., the mass of each grinding ball when using a ball mill, the number of rotations of the grinding device, the degree of sieving and filter pressing, and the metal oxide coating such as a silicon compound-containing layer (and if necessary pH, concentration, stirring temperature, stirring time, type of stirring device, power/degree of stirring (type of stirring blade and diameter, rotational speed, presence or absence of external stirring, etc.), and by appropriately adjusting these, it is possible to control the proportion of primary particles free from agglomeration.

The proportion of bent composite particles in the composite particles is 10% or less on a number basis.
In the composite metal pigment composition according to the present embodiment, the ratio of bent composite particles to the total composite particles contained in the composite metal pigment composition is preferably 10% or less. As a result, the coating film formed using the composite metal pigment composition exhibits excellent design properties, gloss, and suppression of spots, and it becomes easier to improve the stability of water-based coatings.

The ratio of bent composite particles is understood to be an index related to the degree of deformation or breakage of the composite particles. If the ratio of the bent composite particles is 10% or less, the degree of deformation or breakage of the composite particles is small, so that the ratio of the untreated surface (the surface on which the metal oxide film is not formed) of each composite particle is small. As a result, the stability in water-based paint is improved, and it is easier to form a uniform and sufficient coating on individual particles, which further reduces the cohesiveness of individual particles, so the composite metal pigment It is possible to obtain a coating film formed using the composition that exhibits excellent design properties, gloss, and suppression of pimples on the surface of the coating film.
The smaller the proportion of the bent composite particles in the aggregate of composite particles, the better. This proportion is preferably 6% or less, more preferably 3% or less. Since the lower the ratio of bent composite particles, the better, there is no particular lower limit, but ideally it is 0%.

The proportion of bent composite particles in the composite metal pigment composition can be measured by methods known in the art, e.g. It can be measured by forming a coating film using the composition, obtaining an FE-SEM image (field emission scanning electron microscope image) of the cross section, and analyzing the image. More specifically, the ratio of the linear distance between both tips of the cross section of the metal particle in the FE-SEM image to the path length between both tips along the cross section of the metal particle is 0.8 times or less. are determined to be bent particles, and the number ratio thereof can be determined. More specifically, it can be measured, for example, by the method described in the Examples of the present application.
The ratio of bent composite particles to the composite particles can be reduced by, for example, increasing the amount of the specific solvent used, adopting the production method of the second invention and/or the third invention of the present application, and the like. .
In addition, in the process of coating the metal oxide coating (and other coating layers as necessary), pretreatment for improving the dispersibility of the raw material aluminum paste, stirring time, type of stirring device, power / degree of stirring (stirring It can also be controlled by appropriately adjusting the type and diameter of blades, rotation speed, presence/absence of external stirring, etc.).
Furthermore, by pre-treating the raw material aluminum paste, the dispersibility of the particles themselves during the reaction is improved, so mild stirring is sufficient for dispersion, and deformation of the particles due to stirring can be greatly reduced. .

Second coating layer The coating layer of the composite particles contained in the composite metal pigment composition according to the first invention of the present application is not particularly limited except that it has at least one layer of metal oxide coating, but a coating layer other than the metal oxide coating (hereinafter referred to as "second coating layer") can also be formed as necessary.
The second coating layer includes, for example, metals (alkali metals; alkaline earth metals; metals such as manganese, iron, cobalt, nickel, copper, and silver), metal oxides (titanium oxide, zirconium oxide, iron oxide, etc.), It contains at least one of a metal hydrate and a resin (synthetic resin such as acrylic resin, alkyd resin, polyester resin, polyurethane resin, polyvinyl acetate resin, nitrocellulose resin, fluorine resin, etc.) preferable. As the second coating layer, for example, a molybdenum-containing coating, a phosphoric acid compound coating, or the like can be formed. By providing the second coating layer, it is possible to improve the corrosion resistance of the metal particles and promote the formation of a metal oxide coating such as a silicon compound-containing layer.

The second coating layer (if formed) is preferably formed especially between the metal particles and the metal oxide coating, such as the silicon compound-containing layer. Therefore, for example, a layer structure of "metal particles/second coating layer/metal oxide coating" can be preferably adopted. Although not particularly limited, examples of molybdenum-containing coatings include those disclosed in JP-A-2003-147226, WO 2004/096921, JP-A-5979788, and JP-A-2019-151678. can be done. An example of the phosphate compound coating is disclosed in Japanese Patent No. 4633239. Preferred examples of the molybdenum-containing material constituting the molybdenum-containing coating include the mixed coordination heteropolyanion compound disclosed in JP-A-2019-151678.
In another variation, a second coating layer may be formed on the outside of the metal oxide coating, such as a metal particle and silicon compound containing layer. In yet another variation, the components of the second coating layer (such as molybdenum-containing compounds and phosphate compounds) can be included with the silicon compound or the like in a metal oxide coating such as a silicon compound-containing layer.

A mixed-coordination heteropolyanion compound that is preferably used for forming a second coating layer (typically a molybdenum-containing coating) other than the metal oxide coating of the composite particles contained in the composite metal pigment composition according to the first invention of the present application. is not particularly limited, but specifically includes the following examples.

The mixed-coordination heteropolyanion of the mixed-coordination heteropolyanion compound that can be used has a structure in which some of the polyatoms of a heteropolyanion composed of one element are replaced by another element, It exhibits different physical properties from the mixture of each heteropolyanion.

In terms of chemical formulas, when the mixed-coordination _{heteropolyanion is} ^{expressed as [XpMqNrOs]t} _{, the heteropolyanion} becomes [ _XpMqOs ^]t _, and the _isopolyanion [ _MqOs ] ^t . However, the heteroatom X represents an element of the IIIB, IVB and VB groups such as B, Si, Ge, P and As, among which B, Si and P are preferred. Polyatoms M and N represent transition metals such as Ti, Zr, V, Nb, Ta, Mo and W, with Ti, Zr, V, Nb, Mo and W being preferred.
Also, p, q, r, and s represent the number of atoms, and t represents the oxidation number.
Since heteropolyanion compounds have many structures, mixed-coordination-type heteropolyanion compounds can have many more structures. Acids: H ₃ PW _x Mo _12-x O ₄₀ · nH ₂ O (phosphorustomolybdic acid · n-hydrate), H _3+x PV _x Mo _12-x O ₄₀ · nH ₂ O (phosphovanadomolybdic acid · n water hydrate), H ₄ SiW _x Mo _12-x O _{40.nH 2} O (silicotungstomolybdic acid, n-hydrate), H _4+x SiV _x Mo _12-x O _{40.nH 2} O (silicovanadomolybdic acid, n-hydrate) and the like are exemplified. (However, 1≤x≤11, n≥0)

Preferred specific examples of these heteropolyanion compounds include H ₃ PW ₃ Mo ₉ O _{40.nH 2} O, H ₃ PW ₆ Mo ₆ O _{40.nH 2} O, H ₃ PW ₉ Mo ₃ O _{40.nH 2 O , H4PV1Mo11O40.nH2O , H6PV3Mo9O40.nH2O , H4SiW3Mo9O40.nH2O , H4SiW6Mo6O40 . _ _ _ _ _ _ _ _ _ nH2O , H4SiW9Mo3O40.nH2O , H5SiV1Mo11O40.nH2O , H7SiV3Mo9O40.nH2O and other mixed coordination heteropoly _ _ _ _} Acids are exemplified. (However, n≧0)
The mixed-coordination heteropolyanion compound may be used in the form of an acid (so-called mixed-coordination heteropolyacid), or in the form of a (partial or complete) salt with a specific cation as a counterion. good too.

When the mixed-coordination heteropolyanion compound is used in the form of a salt with a specific cation as a counterion, examples of the counter cation source include alkali metals such as lithium, sodium, potassium, rubidium and cesium; magnesium, calcium, strontium, At least one selected from alkaline earth metals such as barium; metals such as manganese, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead and aluminum; inorganic components such as ammonia; are mentioned. Among the inorganic components, salts of alkali metals, alkaline earth metals and ammonia are preferred.
Furthermore, when at least one selected from these alkali metals, alkaline earth metals, and ammonia is used as a counter cation source, H ₃ PW _x Mo _12-x O _{40.nH 2} O (phosphorustungstomolybdate n-hydrate), H _3+x PV _x Mo _12-x O _{40.nH 2} O (phosphovanadomolybdate n-hydrate), H ₄ SiW _x Mo _12-x O _{40.nH 2} O (silicongustomolybdate n-hydrate) ) and H _4+x SiV _x Mo _12-x O _{40.nH 2} O (silicovanadomolybdic acid.n-hydrate) in the form of a salt.

An amine compound, which is an organic component, is also preferably used as a counter cation source for the mixed-coordination type heteropolyanion compound, and a specific example thereof is preferably represented by the following general formula (5).

(R ⁸ -N(-R ¹⁰ )-) _n -R ⁹ (5)
(Wherein, R ⁸ , R ⁹ and R ¹⁰ may be the same or different, and may contain a hydrogen atom, or an ether bond, an ester bond, a hydroxyl group, a carbonyl group, or a thiol group having 1 to 30 carbon atoms. good monovalent or divalent hydrocarbon group, optionally R ⁸ and R ⁹ together form a 5- or 6-membered cycloalkyl group, or additionally a nitrogen or oxygen atom as a bridge member or optionally R ⁸ , R ⁹ and R ¹⁰ together form one or more additional nitrogen and/or oxygen atoms It may form a multi-membered multi-ring that can be included as a bridge member.R ⁸ , R ⁹ and R ¹⁰ are not hydrogen atoms at the same time.n represents an integer of 1 to 2.)

Examples of the amine compound, which is a counter cation source for the mixed-coordination heteropolyanion compound, include linear or branched alkyl primary, secondary, or tertiary amines, tertiary amines having a mixed hydrocarbon group, and alicyclic primary. Amines, primary amines with aromatic ring substituents, alicyclic secondary amines, secondary amines with aromatic ring substituents, asymmetric secondary amines, alicyclic tertiary amines, with aromatic ring substituents Examples include tertiary amines, amines having an ether bond, alkanolamines, diamines, cyclic amines, aromatic amines, or any mixture thereof.

Preferred specific examples of these amine compounds include at least one selected from linear or branched alkyl primary, secondary, or tertiary amines having 4 to 20 carbon atoms, or alkanolamines, For example butylamine, hexylamine, cyclohexylamine, octylamine, tridecylamine, stearylamine, dihexylamine, di-2-ethylhexylamine, linear or branched ditridecylamine, distearylamine, tributylamine, trioctylamine, linear or branched tridecylamine, tristearylamine, N,N-dimethylethanolamine, N-methyldiethanolamine, triethanolamine, morpholine and the like.
At least one selected from the amine compounds represented by the general formula (5), H ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphorustungstomolybdic acid·n-hydrate), and H _3+x PV _x Mo _{12 -x} O _{40.nH 2} O (phosphovanadomolybdate n-hydrate), H ₄ SiW _x Mo _12-x O _{40.nH 2} O (silicotungstomolybdate n-hydrate), H _4+x SiV _x It is more preferably used in the form of a salt with at least one selected from Mo _12-x O _{40.nH 2} O (silicovanadomolybdic acid.n-hydrate).
Among the above mixed-coordination heteropolyanion compounds, H ₃ PW _x Mo _12-x O _{40.nH 2} O (phosphorustungstomolybdic acid.n-hydrate), H _3+x PV _x Mo _12-x O _{40.nH 2} O (phosphovanadomolybdic acid n-hydrate), H ₄ SiW _x Mo _12-x O ₄₀ nH ₂ O (silicone gustomolybdic acid n-hydrate), or mixed coordination heteropolyacids of these Organic amine salts of mixed-coordination heteropolyacids are most preferred.

The second coating layer other than the metal oxide coating of the composite particles contained in the composite metal pigment composition according to the present embodiment further improves the corrosion resistance of the core metal particles (preferably aluminum particles or aluminum alloy particles). of corrosion inhibitors. The corrosion inhibitor to be added is not particularly limited, and any known corrosion inhibitor can be used. The amount used may be within a range that does not inhibit the desired effects of the first invention of the present application. Examples of such corrosion inhibitors include acidic phosphoric acid esters, dimer acids, organophosphorus compounds, metal salts of molybdic acid, and the like.

In the metal oxide coating and/or the second coating layer of the composite particles contained in the composite metal pigment composition, or as a separate layer, from the viewpoint of adhesion and chemical resistance when a coating film is formed, an organic oligomer is further added. Or it can contain a polymer.
In addition, from the viewpoint of storage stability, inorganic phosphoric acids and their salts, and acidic organic (sub)phosphates and their It may contain at least one selected from the group consisting of salts.
These compounds are not particularly limited, and for example, those disclosed in JP-A-2019-151678 can be used.

Composite Metal Pigment Composition The composite metal pigment composition of the first invention of the present application comprises composite particles containing metal particles and one or more layers of metal oxide coating on the surface thereof, and the composite particles are the above (1) to (3). and the composite metal pigment composition satisfies the requirements of (4) to (6) above, and is not subject to any other requirements, but in addition to the composite particles, the solid content (non-volatile as a residue) may include unreacted organosilicon compounds, compounds that form the second coating layer, oligomers or polymers derived from these, and other than the specified amount of the specified solvent according to the above requirement (5) may contain solvents such as water used in the manufacturing process.
The composite metal pigment composition contains an organosilicon compound (for example, at least one of the organosilicon compounds represented by the above general formula (1) and any one of the above general formulas (2), (3) and (4)). A silicon compound which is a hydrolyzate and/or a condensate thereof can be present.
The composite metal pigment composition includes an optional second coating layer-forming compound (in the optional embodiment forming a molybdenum-containing coating as the second coating layer, a molybdenum-containing compound such as a mixed coordination heteropolyanion compounds) may be present.
An optional organic oligomer or polymer may be present in the composite metal pigment composition.
At least one selected from the group consisting of optional inorganic phosphoric acids and their salts, and acidic organic (sub)phosphates and their salts may be present in the composite metal pigment composition.
Solvents, including water/hydrophilic solvents used in the manufacturing process, may be present in the composite metal pigment composition.

The composite metal pigment composition may optionally contain optional ingredients other than those described above. Examples of optional ingredients include at least one of antioxidants, light stabilizers, and surfactants.

Antioxidants that can be used include phenol compounds, phosphorus compounds, and sulfur compounds.

As the light stabilizer, those used as the antioxidants described above can also be used, and benzotriazole-based compounds, benzophenone-based compounds, salicylate-based compounds, cyanoacrylate-based compounds, oxalic acid derivatives, hindered amine-based compounds (HALS), Those typified by hindered phenolic compounds can be used.

Examples of surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl Polyoxyalkylene alkyl phenyl ethers such as ethers, polyoxyalkylene alkyl amino ethers such as polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate sorbitan fatty acid esters such as ate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate; polyethylene glycol mono Polyalkylene glycol fatty acid esters such as laurate, polyethylene glycol monooleate, polyethylene glycol monostearate, polyethylene glycol dilaurate, and polyethylene glycol distearate; representative glycerin fatty acid esters such as lauric acid monoglyceride, stearic acid monoglyceride, and oleic acid monoglyceride nonionic surfactants such as sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene octylphenyl ether sulfate, sodium polyoxyethylene nonylphenyl ether sulfate, triethanolamine lauryl sulfate, sodium lauryl sulfate, lauryl sulfate Sulfuric acid ester salts such as potassium and ammonium lauryl sulfate; sulfonates such as sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate and sodium dialkylsulfosuccinate; anionic interfaces represented by phosphoric acid ester salts such as potassium alkyl phosphate Active agents include cationic surfactants typified by quaternary ammonium salts such as lauryltrimethylammonium chloride, cetyltrimethylammonium chloride and stearyltrimethylammonium chloride, and one or two selected from these. More than seeds can be used be. Among these, particularly preferred examples include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and mixtures thereof.

Method for producing a composite metal pigment composition Although the method for producing a composite metal pigment composition according to the first invention of the present application is not particularly limited, it may be produced by the method of the second invention of the present application and/or the method of the third invention of the present application. is particularly preferred. The production method of the second invention of the present application and the production method of the third invention of the present application are capable of producing a composite metal pigment composition having a high nonvolatile content (solid content) while effectively preventing aggregation and inhibition of composite particles. Therefore, it is particularly suitable for producing the composite metal pigment composition according to the first invention of the present application.
The production method of the second invention of the present application and the production method of the third invention of the present application are not limited to the production of the composite metal pigment composition according to the first invention of the present application, and are suitable for the production of various composite metal pigment compositions. used for

The manufacturing method of the second invention of the present application is
A method for producing a composite metal pigment composition comprising the following steps 1) to 3),
1) a step of dispersing metal particles in a solvent; 2) a step of coating the metal particles with a metal oxide; Washing, filtering, and solvent volatilization steps The solvent is a mixed solvent of two or more solvents that are compatible with each other and have a boiling point different from each other by 10 ° C. or more,
The above manufacturing method, wherein the solvent volatilization in step 3) is performed in a slurry state containing the composite particles and the solvent.
The manufacturing method of the third invention of the present application is
A method for producing a composite metal pigment composition comprising the following steps 1) to 3),
1) a step of dispersing metal particles in a solvent; 2) a step of coating the metal particles with a metal oxide; Washing, Filtration, and Solvent Volatilization The above-described production method, wherein the solvent volatilization in step 3) is performed in three or more steps.

That is, both the manufacturing method of the second invention of the present application and the manufacturing method of the third invention of the present application are
1) dispersing metal particles in a solvent;
2) coating the metal particles with a metal oxide; and 3) washing, filtering, and solvent volatilizing the metal particles obtained in step 2) and the composite particles having the metal oxide coating formed thereon. have a process.
In the second invention of the present application, the solvent is a mixed solvent of two or more solvents that are compatible with each other and have boiling points different from each other by 10° C. or more, and the solvent volatilization in step 3) is performed by the composite particles and the solvent. is performed in a state of slurry containing The second invention differs from the third invention in that the solvent volatilization in 3) is performed in three or more steps, whereas the second invention does not have such limitations.
Each of these steps will be described below.

1) Dispersing metal particles in a solvent In step 1), metal particles are dispersed in a solvent. By dispersing the metal particles in the solvent, it is possible to suppress aggregation of the particles in the subsequent step 2) of coating the metal particles with the metal oxide, and as a result, the resulting composite particles have good dispersibility. As a result, the proportion of primary particles free from agglomeration can be greatly increased.
The method for dispersing the metal particles in the solvent is not particularly limited, but methods such as adding the metal particles to the solvent and then stirring or irradiating with ultrasonic waves are preferably employed.
It is also preferable to perform a pretreatment in order to improve the dispersibility of the metal particles.

Stirring can be carried out with a known or commercially available stirring device. For example, at least one of kneader, kneader, rotary vessel agitator, agitating reactor, V-type agitator, double cone agitator, screw mixer, sigma mixer, flash mixer, airflow agitator, ball mill, edge runner, etc. one can be used.

Among these stirrers, it is preferable to use a device that stirs with a stirring blade (impeller). The stirring blade exerts a pressure shearing action as well as a circulating action for fluidizing the entire system containing the metal particles and the solvent, so that the metal particles can be dispersed more effectively by suppressing their agglomeration.

The shape of the stirring blade is not particularly limited, and for example, anchor type, propeller type, turbine type, fan turbine type, paddle type, inclined paddle type, and gate type can be used. Moreover, the stirring blades having these shapes can be combined in multiple stages.

The stirring speed is preferably such that the stirring impeller is not exposed by the vortex generated by the stirring. Also, in order to suppress the vortex caused by stirring, a cylindrical tank, a rectangular tank, or a tank provided with a baffle plate can be preferably used.

The linear speed of stirring (tip speed of stirring blade) is preferably 0.5 to 30 m/s, more preferably 1 to 20 m/s. By setting the linear speed of stirring in the range of 0.5 to 30 m / s, the dispersibility of the metal particles can be improved, and the aggregation of individual particles is small, and excellent design, gloss, and coating can be obtained. It becomes easier to obtain a composite metal pigment composition with a film appearance and less gassing. In addition, when the linear speed of stirring is within the above range, damage to the metal particles (for example, scale-like aluminum powder) can be prevented, and aggregation of the particles can be effectively suppressed.

Ultrasonic treatment is not particularly limited, but can be performed at usually 10 to 1000 W, preferably 50 to 800 W, for usually 20 seconds to 10 minutes, preferably 30 seconds to 5 minutes.

As a pretreatment, for example, when metal particles as a raw material are dispersed in an inert solvent and supplied, the solvent can be replaced with the same solvent as that used in the coating treatment. Furthermore, if desired, a heating treatment is performed for a certain period of time so that the solvent is sufficiently familiarized with the surface of the metal particles, whereby agglomeration occurring in the step 2) of coating the metal particles with the metal oxide can be greatly suppressed. The heat treatment temperature is preferably about 30 to 60° C., and the treatment time is preferably optimized between 3 hours and 7 days. Since a hydrophilic solvent such as ethanol, isopropanol or methoxypropanol is preferably used in the step of coating, the same hydrophilic solvent as used in the reaction is preferably used in the pretreatment.
Furthermore, addition of a small amount of surfactant at this time is also effective in suppressing aggregation due to pretreatment. The surfactant is not particularly limited, but nonionic surfactants and anionic surfactants are preferred, and nonionic surfactants are particularly preferred.

1) The step of dispersing metal particles in a solvent can be carried out usually at 10 to 80°C, preferably 15 to 70°C, most preferably around room temperature (about 20 to 60°C). In addition, 1) the step of dispersing the metal particles in the solvent (including ultrasonic treatment, if any) can be carried out for 5 minutes to 20 hours, preferably 10 minutes to 5 hours.

2) Step of Coating Metal Particles with Metal Oxide Following the step of 1) dispersing the metal particles in a solvent, the step of 2) coating the metal particles with the metal oxide is carried out to form a metal oxide coating on the metal particles. can be formed.
As described above, it is preferable to use a silicon oxide for the metal oxide coating. Therefore, an embodiment in which at least one layer in the metal oxide coating is a silicon compound-containing layer will be described below as a specific example of step 2). , the step of forming the silicon compound-containing layer will be described.

Step of Forming Silicon Compound-Containing Layer In the forming step , the silicon compound-containing layer contains, for example, metal particles, a silicon-containing raw material containing at least one organosilicon compound, a solvent, and optionally other optional components. A silicon compound-containing layer is formed by reacting the mixture.
Since the metal particles are dispersed in the solvent in step 1), the silicon-containing raw material is usually added here in step 2).

As the metal particles, the metal particles described above can be used, and in particular, aluminum or aluminum alloy particles can be preferably used. As for the particle shape, it is preferable to use scale-like metal particles as described above. As the metal particles, known or commercially available ones (typically pasty aluminum flakes) can be used.

The content (solid content) of the metal particles in the mixed solution is not particularly limited, and can be appropriately set according to the type and particle size of the metal particles used.

An organic silicon compound can be used as the silicon-containing raw material. The organosilicon compound is not limited, but preferably those mentioned above can be used.
An organosilicon compound represented by the above formula (1) (typically tetraalkoxysilane) and/or a condensate thereof, and a silane coupling agent represented by any one of the above formulas (2) to (4). At least one type can be preferably used.
Hereinafter, the case where tetraalkoxysilane is used as the organosilicon compound represented by the above formula (1) will be described as an example. In the following, tetraalkoxysilane and/or its condensate may be collectively referred to simply as "tetraalkoxysilane".

When the tetraalkoxysilane represented by the above formula (1) and the silane coupling agent represented by any of the above formulas (2) to (4) are used in combination, a method of using a mixture of both ("second 1 method”) can be employed. Alternatively, a method comprising the step of subjecting the metal particles to one treatment to form a first silicon compound-containing layer and the other treatment to form a second silicon compound-containing layer (referred to as a "second method" ) can also be adopted.

As the first method, for example, a pH is appropriately adjusted to cause a hydrolysis/condensation reaction between a tetraalkoxysilane and a silane coupling agent to form a silicon compound-containing layer.

As a second method, for example, by appropriately adjusting the pH of the mixed solution containing the metal particles and the tetraalkoxysilane represented by the above formula (1), the tetraalkoxysilane is hydrolyzed/condensed to react the surface of the metal particles. forming a first silicon compound-containing layer (for example, a silica coating made of amorphous silica), and metal particles and a silane coupling agent represented by any of the above formulas (2) to (4) A method including the step of forming a second silicon compound-containing layer on the surface of the first silicon compound-containing layer by hydrolyzing/condensing the silane coupling agent by adjusting the pH of the mixed solution.

The amount of the tetraalkoxysilane represented by the formula (1) or the condensate thereof to be used can be appropriately set according to the type of tetraalkoxysilane to be used. The amount used is 2 to 200 parts by mass based on 100 parts by mass of the metal particles (solid content), for example, from the viewpoint of the coating treatment effect and from the viewpoint of suppressing the aggregation of the metal particles or the deterioration of the glitter feeling. Well, it is more preferably 5 to 100 parts by mass.

The amount of the silane coupling agent represented by any of the above formulas (2) to (4) is not particularly limited, but is usually 0.1 to 20 parts by mass with respect to 100 parts by mass of the metal particles (solid content). It may be about 1 part, and it is particularly preferably 1 to 5 parts by mass. When the amount used is about 0.1 to 20 parts by mass, the desired coating effect and desired physical properties of the coating film can be obtained.

The solvent in the mixed solution, that is, the solvent for the hydrolysis reaction and/or condensation reaction of the organosilicon compound may be appropriately selected depending on the type of silicon-containing raw material to be used. An organic solvent or a mixed solvent thereof can be used. By using these solvents, the uniformity of the reaction and the uniformity of the resulting hydrolyzate and/or condensation reaction product can be enhanced. In the embodiment in which the silicon compound-containing layer is formed directly on the metal particles, it is particularly preferable that the solvent of the mixture contains a hydrophilic organic solvent from the viewpoint of avoiding rapid reaction between the metal particles and water. . In this embodiment, a mixed solvent of water and a hydrophilic organic solvent can be suitably used.

Examples of hydrophilic organic solvents include, but are not limited to, alcohols such as methanol, ethanol, propanol, butanol, isopropanol, and octanol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, Ether alcohols such as propylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether and their esters; ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, polyoxyethylene glycol , polyoxypropylene glycol, ethylene propylene glycol; ethyl cellosolve, butyl cellosolve, acetone, methoxypropanol, ethoxypropanol, and other alkoxy alcohols. These can be used alone or in combination of two or more.

The amount of solvent used in the step of forming the silicon compound-containing layer (excluding the amount of solvent for pre-dispersion of metal particles) is not limited, but is usually per 100 parts by mass of metal particles (solid content). 100 to 10,000 parts by mass, preferably 200 to 2,000 parts by mass. When the amount of the solvent used is 100 parts by mass or more, an increase in the viscosity of the mixed liquid (slurry) is suppressed, and suitable stirring becomes possible. In addition, when the amount of the solvent used is 10,000 parts by mass or less, it is possible to prevent the recovery and recycling costs of the treatment liquid from increasing. In addition, in the case of the second method, the amount of solvent used here refers to the total amount of solvent used for forming the first silicon compound-containing layer and forming the second silicon compound-containing layer.

If necessary, other additives may be added to the mixed liquid as long as the effects of the first invention of the present application are not impaired. Examples thereof include catalysts such as hydrolysis catalysts and dehydration condensation catalysts, as well as surfactants and metal corrosion inhibitors.

Among these, a hydrolysis catalyst can be preferably used. By blending the hydrolysis catalyst, it is possible to adjust the pH of the mixed liquid and efficiently hydrolyze and dehydrate the organosilicon compound. As a result, the silicon compound-containing layer is efficiently formed on the surface of the metal particles It is possible to reliably form them.

A known or commercially available hydrolysis catalyst may be used, and is not particularly limited. Examples of hydrolysis catalysts include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; organic acids such as benzoic acid, acetic acid, chloroacetic acid, salicylic acid, oxalic acid, picric acid, phthalic acid, and malonic acid; and vinylphosphonic acid. , 2-carboxyethanephosphonic acid, 2-aminoethanephosphonic acid, octanephosphonic acid and the like can be used. These hydrolysis catalysts may be used singly or in combination of two or more.
Examples of hydrolysis catalysts include inorganic alkalis such as ammonia, sodium hydroxide and potassium hydroxide; inorganic alkali salts such as ammonium carbonate, ammonium hydrogen carbonate, sodium carbonate and sodium hydrogen carbonate; monomethylamine, dimethylamine, Amines such as trimethylamine, monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, ethylenediamine, pyridine, aniline, choline, tetramethylammonium hydroxide, guanidine; ammonium formate, Organic acid salts such as ammonium acetate, monomethylamine formate, dimethylamine acetate, pyridine lactate, guanidinoacetic acid, and aniline acetate can also be used. These hydrolysis catalysts can be used alone or in combination of two or more.

The amount of the hydrolysis catalyst added is not particularly limited, but it is usually 0.01 to 20 parts by mass, particularly 0.02 to 10 parts by mass, per 100 parts by mass of the metal particles (solid content). is preferred. When the addition amount is 0.01 parts by mass or more, a sufficient amount of the silicon compound-containing layer can be deposited. Also, when the amount added is 20 parts by mass or less, aggregation of the metal particles can be effectively suppressed.

In the production of the composite metal pigment composition according to the first invention of the present application, it is preferable to prepare the mixed solution under moderately strong stirring.
The temperature of the mixed liquid may be normal temperature or under heating. In general, the temperature of the mixture should be 20 to 90.degree. C., preferably 30 to 80.degree. When the temperature is 20° C. or higher, the formation speed of the silicon compound-containing layer can be increased and the treatment time can be shortened. On the other hand, when the temperature is 90° C. or lower, the reaction can be easily controlled, and the probability of obtaining desired composite particles can be increased.

The stirrer for stirring the mixed liquid is not particularly limited, and a known stirrer capable of efficiently and uniformly stirring the mixed liquid containing the aluminum particles and the organosilicon compound can be used. Specific examples include kneaders, kneaders, rotary vessel agitators, agitating reactors, V-type agitators, double cone agitators, screw mixers, sigma mixers, flash mixers, airflow agitators, ball mills, edge runners, etc. is mentioned.

The temperature of the mixture containing the metal particles and the organosilicon compound is usually about 10 to 100.degree. C., preferably 30 to 80.degree. When this temperature is 10° C. or higher, the reaction time for obtaining a sufficient treatment effect can be shortened. Further, when this temperature is 100° C. or less, it becomes easier to control the reaction for obtaining the desired composite metal pigment composition.

The stirring time of the mixed solution is not particularly limited as long as it is sufficient for forming the desired silicon compound-containing layer. The stirring time is, for example, preferably 0.5 to 10 hours, more preferably 1 to 5 hours. A sufficient treatment effect can be obtained by stirring for 0.5 hours. Moreover, an increase in processing cost can be suppressed by setting the stirring time to 10 hours or less.

In the mixed solution, a silicon compound-containing layer is formed on the surface of the metal particles (or through the second coating layer) by hydrolyzing/condensing the silicon-containing raw material. This hydrolysis/condensation reaction can be carried out particularly by adjusting the pH of the mixture.

When adjusting the pH, since the pH value of the mixed solution changes particularly at the stage where the silicon compound-containing layer is formed on the surface of the metal particles (or via the second coating layer), the pH value must be within a certain range. It is desirable to make appropriate adjustments so that it can be maintained. At that time, it is desirable to adjust the pH value by adding a hydrolysis catalyst. may be adjusted.

When a basic hydrolysis catalyst is used as the hydrolysis catalyst, the pH value is preferably 7-13. A silicon compound-containing layer can be rapidly formed by a pH value of 7 or more. On the other hand, when the pH value is 13 or less, aggregation of metal particles and deterioration of brightness can be suppressed, and generation of hydrogen gas due to corrosion can be prevented.

When an acidic hydrolysis catalyst is used as the hydrolysis catalyst, the pH value is preferably 1.5-7, more preferably 2-6. When the pH value is 1.5 or more, the reaction is appropriately controlled, making it easy to obtain a composite metal pigment composition containing desired composite particles. On the other hand, when the pH value is 7 or less, the deposition rate of the silicon compound-containing layer can be kept high.

In the case of adopting either the first method or the second method, the hydrolyzate and/or condensate of the organosilicon compound represented by the general formula (1) is a metal particle ( It is preferable to add 0.01 to 50 parts by mass, more preferably 1 to 30 parts by mass, based on 100 parts by mass of solid content) in terms of the state in which the hydrolysis and condensation reactions are completed. Further, the silane coupling agent represented by any one of the above general formulas (2) to (4), and / or hydrolyzate derived from partial condensate thereof and / or condensate thereof, metal particles (solid 0.01 to 10 parts by mass, more preferably 0.05 to 2 parts by mass, based on 100 parts by mass of hydrolysis and condensation reactions.

The amount of the hydrolyzate and/or condensate of the organosilicon compound represented by general formula (1) to be added is the amount of the organosilicon compound represented by general formula (1) used in the production of the composite metal pigment composition. It can be calculated by multiplying the mass by the mass ratio before and after the reaction when all of the organosilicon compound is hydrolyzed and condensation reaction occurs.
For example, when tetraethoxysilane (TEOS) is used as the organosilicon compound represented by the general formula (1), the hydrolyzate of the organosilicon compound is calculated using the following mass ratios before and after the hydrolysis and condensation reaction. and/or the amount of the condensate to be added can be calculated.
(Hydrolysis)
Si( _OC2H5 ) _{4 (} molecular weight: 208) ₊ 4H2O
→ Si(OH) ₄ (molecular weight: 96) + (C ₂ H ₅ OH) ₄
(condensation)
Si(OH) ₄ (molecular weight: 96) + Si(OH) ₄ (molecular weight: 96)
→ (SiO ₂ ) ₂ (molecular weight: 60×2) + 4H ₂ O
Before and after the above hydrolysis and condensation reactions, the mass becomes 60/208=0.288 times. The amount of the hydrolyzate and/or its condensate added is 0.288 times that amount, ie, 2.88 parts by mass.

Similarly, the amount of the hydrolyzate and/or condensate of the silane coupling agent represented by any one of the general formulas (2) to (4) is also the same as the general amount used in the production of the composite metal pigment composition. The silane coupling agent and / or partial condensate thereof are all hydrolyzed and condensed into the mass of the silane coupling agent and / or partial condensate thereof represented by any one of formulas (2) to (4) It can be calculated by multiplying the mass ratio before and after reaction when reacted.
For example, when methyltrimethoxysilane is used as the silane coupling agent represented by the general formula (2), the hydrolysis of the silane coupling agent is performed using the following mass ratios before and after the hydrolysis and condensation reaction. It is possible to calculate the addition amount of the product and/or its condensate.
(Hydrolysis)
_{CH3Si(OCH3)3 ( molecular} weight: 136) + _3H2O
→ CH ₃ Si(OH) ₃ (molecular weight: 94) + (CH ₃ OH) ₃
(condensation)
CH3Si(OH) ₃ (molecular weight: 94) + _CH3Si (OH) _{3 (} molecular weight: 94)
→ (SiCH ₃ O _1.5 ) ₂ (molecular weight: 67×2) + 3H ₂ O
Before and after the above hydrolysis/condensation reaction, the mass becomes 67/136=0.49 times. When used, the amount of the hydrolyzate and/or the condensate added is 0.49 times that, ie, 0.60 parts by mass.

3) After the step of washing, filtering, and volatilizing the composite particles 2) of coating the metal particles with the metal oxide, the obtained composite particles are recovered to obtain the desired composite metal pigment composition. 3) The composite particles can be washed, filtered, and solvent volatilized.
In producing the composite metal pigment composition of the first invention of the present application, step 3) is not essential, but is preferably carried out.
In the method for producing a composite metal pigment composition of the second invention of the present application, step 3) is carried out, and the solvent at that time is a mixture of two or more solvents that are compatible with each other and have a boiling point difference of 10°C or more. It is a solvent, and the solvent volatilization in step 3) is performed in a slurry state containing the composite particles and the solvent.
In the method for producing a composite metal pigment composition of the third invention of the present application, step 3) is carried out, and solvent volatilization in step 3) is carried out in three or more steps.

The washing in step 3) can be performed by a method commonly used in this technical field. For example, the slurry or cake containing the composite particles obtained in step 2) can be washed with an organic solvent. Washing can remove water, unreacted materials, solvents, etc. that are undesirable in the final composite metal pigment composition from the slurry, cake, etc. containing the composite particles.
Stirring is preferably carried out in washing, and the stirring conditions are not particularly limited, but for example, conditions similar to those described above in relation to step 1) can be employed.
There are no particular restrictions on the temperature, time, etc. for washing in step 3), but it is usually carried out at 10 to 70°C, preferably 15 to 60°C, for 5 to 180 minutes, preferably 10 to 120 minutes. can.

For washing, an organic solvent is preferably used, and a hydrophilic organic solvent is more preferably used for convenience in removing moisture and later using the composite metal pigment composition in a water-based paint. It is particularly preferable that the hydrophilic organic solvent has a boiling point of 80 to 150°C. It becomes easier to satisfy the requirement that a hydrophilic solvent having a boiling point of 80 to 150° C. accounts for more than mass %. Preferred examples of hydrophilic solvents having a boiling point of 80 to 150° C. include methoxypropanol, isopropanol, isobutanol, normal butanol and normal propanol.
The number of times of washing is not particularly limited, and washing may be performed only once, or may be performed multiple times, for example, 2 to 5 times. When washing is performed multiple times, washing and filtration may be alternately performed. Another preferred example is washing by continuously or intermittently flowing a washing liquid using a Nutsche type filter.

Filtration in step 3) can be performed by a method commonly used in this technical field. For example, a polypropylene filter cloth having an air permeability of 10 to 100 ml/cm ² /min, preferably 20 to 80 ml/cm ² /min, or a metal filter, glass filter, or ceramic filter cloth having an equivalent mesh size can be used. Using a filter or the like, filtering by suction filtration or pressure filtration using a Nutsche type filter, or a technique such as a filter press, belt press, or centrifugal filter can be appropriately adopted. Filtration can remove water, unreacted substances, solvents undesired in the final composite metal pigment composition, and the like from the composite particles obtained in step 2).
There are no particular restrictions on the temperature and pressure of filtration in step 3), but usually when a Nutsche type filter is used, the temperature is 10 to 70 ° C., preferably 15 to 60 ° C., and the pressure is 0.11 to 0.9 MPa. , preferably from 0.15 to 0.5 MPa.
The solid content of slurry, cake, etc. containing composite particles after filtration is preferably 75% by mass or more, more preferably 80 to 98% by mass, and particularly preferably 85 to 95% by mass.
From the viewpoint of low VOC, etc., it is preferable that the solid content of slurry, cake, etc. containing composite particles after filtration is high. Aggregation and deformation of the composite particles may be caused, so it is preferable to set the pressure in consideration of this point as well.

Filtration may be appropriately combined with solid-liquid separation techniques other than filtration, such as centrifugation and decantation.
The number of times of filtration is not particularly limited, and filtration may be performed only once, or washing and filtration may be alternately performed multiple times. By alternately performing washing and filtering multiple times, water, unreacted substances, undesired solvents and the like in the final composite metal pigment composition are more effectively removed, and (5) composite in the first invention of the present application It becomes easier to satisfy the requirement that a hydrophilic solvent having a boiling point of 80 to 150° C. accounts for 80% by mass or more of the non-solid content of the metal pigment composition.
During filtration, it is also desirable to pass gas through the surface of the slurry or cake and through the voids to volatilize the solvent. As a result, the low boiling point solvent is preferentially volatilized, making it easier to obtain a composite metal pigment composition with a high solid content in which the high boiling point solvent content remains.

Solvent volatilization in step 3) can be carried out by a method commonly used in this technical field. For example, the solvent can be volatilized by heating, depressurization, ventilation, or a combination of these. A composite metal pigment composition that satisfies the requirement that the solid content concentration of the metal pigment composition is 70 to 95% by mass can be efficiently produced. In addition, solvent volatilization can remove undesired solvents and the like in the composite metal pigment composition. A composite metal pigment composition that satisfies the requirement that the solvent be occupied at 150° C. can be produced more easily.

The temperature, pressure, time, etc. of solvent volatilization in step 3) are not particularly limited, but usually the temperature is 15 to 100° C., preferably 20 to 80° C., more preferably 30 to 70° C., and the pressure is 0 in absolute pressure. .1 (atmospheric pressure) to 0.001 MPa, preferably 0.05 to 0.01 MPa, while confirming the degree of solvent volatilization.
When the solvent is volatilized by ventilation, it is preferable to use dry air, and the dew point and the flow rate of ventilation are preferably adjusted appropriately while checking the degree of volatilization of the solvent.
The composite metal pigment composition may be directly obtained by solvent volatilization, or the composite metal pigment composition may be obtained through further steps. The solid content of the composite metal pigment composition after volatilization of the solvent is preferably 75% by mass or more, more preferably 80 to 98% by mass, and particularly preferably 85 to 95% by mass.

In the method for producing a composite metal pigment composition of the second invention of the present application, the solvent in step 3) is a mixed solvent of two or more solvents that are compatible with each other and have a boiling point difference of 10° C. or more. A mixed solvent of two or more solvents that are compatible with each other and have boiling points different by 10°C or more, i.e., a mixed solvent in which a low boiling point solvent is mixed, replaces the solvent used in each preceding step, and replaces the solvent with a low boiling point solvent. By selectively volatilizing , it is possible to selectively leave a solvent desired to be left, for example, a hydrophilic solvent with a boiling point of 80 to 150°C. In addition, since volatilization of the low boiling point solvent is relatively easy, and high temperature or extreme pressure reduction is not required, the solid content concentration can be improved relatively easily while suppressing deformation and aggregation of the composite particles. be able to.
The difference in boiling points between the two or more solvents constituting the mixed solvent is preferably 10 to 80°C, particularly preferably 20 to 60°C.
Methoxypropanol, isobutanol, normal butanol and the like can be preferably used as the high boiling point solvent.
Isopropanol, normal propanol, ethanol and the like can be preferably used as the low boiling point solvent.
It is particularly preferable to use a combination of methoxypropanol as the high-boiling solvent and isopropanol as the low-boiling solvent.

Further, in the method for producing a composite metal pigment composition of the second invention of the present application, the solvent volatilization in step 3) is carried out in a slurry state containing the composite particles and the solvent.
In step 3), a mixed solvent of two or more solvents that are compatible with each other and have boiling points different from each other by 10° C. or more is volatilized in the form of a slurry containing the composite particles and the solvent, thereby obtaining a low boiling point side. It becomes easier to volatilize the solvent and leave the high boiling point solvent in the composite metal pigment composition.

In the method for producing a composite metal pigment composition according to the third invention of the present application, the solvent volatilization in step 3) is carried out in three or more steps. At this time, the solvent volatilization may be continued in three or more stages, but the solvent component contained in the slurry is made uniform throughout between the solvent volatilization in the first stage and the solvent volatilization in the subsequent stage. It is preferable to carry out a process, for example, a process of stirring, aging, or the like. In such a step of homogenizing the solvent component, a new solvent may be added to partially replace the solvent.
Solvent volatilization is carried out in three or more stages, preferably by alternately volatilizing and dispersing, to suppress the formation of local areas with less solvent and to effectively prevent aggregation and deformation of composite particles. A composite metal pigment composition having a high solids content and a desirable solvent composition, such as the composite metal pigment composition of the first invention, can be produced relatively easily and efficiently while effectively preventing this.

In the method for producing the composite metal pigment composition of the second invention and the third invention of the present application, it is preferable to use a solvent with a low water content from the viewpoint of suppressing aggregation of the composite particles. In particular, it is preferable that the water content of the solvent is low when the solvent is volatilized in step 3). The water content of the solvent is preferably 10% by mass, more preferably 5% by mass or less, and particularly preferably 1% by mass or less.
At this time, the water content of the entire system of the composite metal pigment composition obtained is preferably 0.1% by mass or less, more preferably 0.05% by mass or less. It becomes easier to reduce the content to 0.1% by mass or less, more preferably 0.003% by mass or less.

Other steps Preferably, in the production of the composite metal pigment composition of the first invention of the present application by the method for producing a composite metal pigment composition of the second invention and/or the third invention of the present application, the above steps 1) to 3) In addition to the above, a step of pulverizing the metal particles, a step of forming a coating layer other than the metal oxide coating, and the like may be included.

Pulverization, sieving, filtering, etc. of metal particles Prior to the above step 1) of dispersing the metal particles in a solvent, the metal particles may be pulverized, sieved, and/or filtered. By pulverizing, sieving, and/or filtering the metal particles, the particle size of the metal particles becomes more uniform and fine. Therefore, from the viewpoint of producing a composite metal pigment composition containing uniform and fine composite particles, preferable.
Here, the case where aluminum powder is used as the metal particles will be described as an example.
Aluminum powder is generally produced by using atomized aluminum powder and/or aluminum foil using methods commonly used in the pigment industry, such as dry ball milling, wet ball milling, attritor method, and stamp milling, and adding grinding aids. It is obtained by pulverizing in the presence of an inert solvent to form so-called flakes, and after this step, undergoing necessary steps such as sieving (classification), filtering, washing, mixing, and the like.
Examples of grinding aids herein include fatty acids, fatty amines, fatty amides, fatty alcohols, and the like. Generally, oleic acid, stearic acid, stearylamine and the like are preferred. Examples of inert solvents include those exhibiting hydrophobic properties such as mineral spirits, solvent naphtha, toluene and xylene, and these can be used alone or in combination. Grinding aids and inert solvents are not limited to these.
As the pulverization step, pulverization by a wet ball mill method is preferable from the viewpoint of preventing dust explosion and ensuring safety.

When aluminum particles are employed as the metal particles, commercially available pasty aluminum flakes obtained through such pulverization, sieving and filtration can be used. The paste-like aluminum flakes may be used as they are, or may be used after previously removing fatty acids and the like from the surface with an organic solvent or the like.

Step of forming the second coating layer The composite particles constituting the composite metal pigment composition of the first invention of the present application have, in addition to the metal oxide coating, another coating layer (second coating layer), preferably a metal or metal oxide. , a coating layer comprising at least one selected from metal hydrates and resins. The second coating layer (if formed) is preferably formed especially between the metal particles and the metal oxide coating, such as the silicon compound-containing layer. Therefore, a layer structure of "metal particles/second coating layer/metal oxide coating" can be preferably employed.
The second coating layer is not particularly limited, but may be a molybdenum-containing coating, a phosphate compound coating, or the like. Preferred examples of the molybdenum-containing material constituting the molybdenum-containing coating include the mixed coordination heteropolyanion compound disclosed in JP-A-2019-151678. Examples of constituents of the second coating layer, including mixed-coordination heteropolyanion compounds, are described above.
Hereinafter, an embodiment in which a molybdenum-containing coating is formed as a second coating layer between metal particles and a metal oxide coating such as a silicon compound-containing layer will be described as an example.

When forming the molybdenum-containing coating as the second coating layer between the metal particles and the metal oxide coating such as the silicon compound-containing layer, prior to forming the metal oxide coating such as the silicon compound-containing layer, the metal particles and the molybdenum compound ( A molybdenum-containing film can be formed on the surface of the metal particles by stirring the mixed solution containing (typically, mixed-coordination type heteropolyanion compound).

The method for forming the molybdenum-containing coating on the surface of the metal particles is not particularly limited, and any method may be used as long as the mixed liquid containing the metal particles and the molybdenum compound in the aqueous solvent can be uniformly stirred. For example, a molybdenum-containing coating can be formed on the surface of the metal particles by stirring or kneading a mixture containing metal particles and a molybdenum compound in a slurry or paste state. The molybdenum compound may be dissolved or dispersed in the mixture.

Further, the stirrer for stirring the mixed liquid containing the metal particles and the molybdenum compound is not particularly limited, and a known stirrer capable of efficiently and uniformly stirring the mixed liquid containing the metal particles and the molybdenum compound is used. machine can be used. Specific examples include kneaders, kneaders, rotary vessel agitators, agitating reactors, V-type agitators, double cone agitators, screw mixers, sigma mixers, flash mixers, airflow agitators, ball mills, edge runners, etc. is mentioned. Examples of the stirring blades of the stirrer include, but are not limited to, anchor blades, paddle blades, propeller blades, turbine blades, and the like.

The amount of the molybdenum compound used can be appropriately set according to the type of molybdenum compound used. The amount used is generally 0.02 to 20 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of the metal particles (solid content). When the content is 0.02 parts by mass or more, a sufficient treatment effect can be obtained. Moreover, when the content is 20 parts by mass or less, the resulting composite metal pigment composition can maintain high luster.

As a solvent used for mixing the metal particles and the molybdenum compound, water, a hydrophilic organic solvent, or a mixed solvent thereof can usually be used.

Examples of hydrophilic organic solvents include alcohols such as methanol, ethanol, propanol, butanol, isopropanol, octanol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monoethyl ether. , propylene glycol monomethyl ether, dipropylene glycol monomethyl ether and other ether alcohols and their esters; ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, polyoxyethylene glycol, polyoxypropylene glycol , ethylene propylene glycol; ethyl cellosolve, butyl cellosolve, acetone, methoxypropanol, ethoxypropanol, and other alkoxy alcohols. These can use 1 type(s) or 2 or more types.

The amount of solvent used in the step of forming the second coating layer (excluding the amount of solvent for pre-dispersion of metal particles) is not particularly limited, but is usually per 100 parts by mass of metal particles (solid content) It is preferably 50 to 5000 parts by mass, more preferably 100 to 2000 parts by mass. When the amount of the solvent used is 50 parts by mass or more, uneven distribution of the molybdenum compound and aggregation of the metal particles can be suppressed. Further, when the amount of the solvent used is 5000 parts by mass or less, a sufficient effect of treating the metal particles with the molybdenum compound can be obtained.

The temperature of the mixture containing the metal particles and the molybdenum compound is usually about 10 to 100.degree. C., preferably 30 to 80.degree. When this temperature is 10° C. or higher, the reaction time for obtaining a sufficient treatment effect can be shortened. Further, when this temperature is 100° C. or less, it becomes easier to control the reaction for obtaining the desired composite metal pigment composition.

The stirring time of the mixed solution is not particularly limited as long as it is sufficient for forming the desired molybdenum-containing coating. The stirring time is, for example, preferably 0.5 to 10 hours, more preferably 1 to 5 hours. A sufficient treatment effect can be obtained by stirring for 0.5 hours. Moreover, an increase in processing cost can be suppressed by setting the stirring time to 10 hours or less.

After the mixture containing the metal particles and the molybdenum compound has been stirred, the particles having the second coating layer formed thereon can be collected. In this case, well-known washing, solid-liquid separation, etc. can be appropriately carried out as necessary. For example, it is preferable to remove water and unreacted substances from the cake containing the metal particles having the molybdenum-containing coating by washing the mixture with a hydrophilic solvent and then filtering it with a filter or the like. In this manner, a molybdenum-containing coating, which is the second coating layer, can be formed. Also when forming other 2nd coating layers, it can implement according to said method.

In an embodiment in which a second coating layer (hereinafter, a molybdenum-containing coating is described as an example) and then a metal oxide coating (hereinafter, a silicon compound-containing layer is described as an example) is formed on the metal particles, the metal particles and After the stirring of the mixture containing the molybdenum compound is completed, the silicon compound source (typically represented by the above formula (1)) is added to the system without recovering the particles on which the second coating layer is formed. organosilicon compounds such as tetraalkoxysilanes and/or condensates thereof, and at least one of the silane coupling agents represented by any of the above formulas (2) to (4)) water and/or hydrophilic An organic solvent dispersion may be directly added and stirred. At this time, an organosilicon compound represented by the above formula (1), such as a tetraalkoxysilane and/or a condensate dispersion thereof, is added to the system containing the particles on which the second coating layer is formed, and then the above A dispersion of at least one silane coupling agent represented by any one of formulas (2) to (4) may be added and stirred.

Applications of the composite metal pigment composition The composite metal pigment composition of the first invention of the present application and the composite metal pigment composition produced by the production method of the second invention and/or the third invention of the present application are organic solvent-based paints, It can be used for ink and the like. In addition, this composite metal pigment composition can be added to a water-based paint or water-based ink in which a resin, which is a coating film-forming component (binder), is dissolved or dispersed in a medium mainly containing water, thereby producing a metallic water-based paint or water-based ink. It can be a metallic water-based ink. The composite metal pigment composition can also be kneaded with a resin or the like and used as a water-resistant binder or filler. Antioxidants, light stabilizers, and surfactants may be added when the composite metal pigment composition is blended into water-based paints, water-based inks, resins, or the like.

When the composite metal pigment composition is used for paint or ink, it may be added to the (aqueous) paint or (aqueous) ink as it is, but it is preferable to disperse it in a solvent before adding it. Solvents to be used include water, texanol, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and the like. Examples of these resins include acrylic resins, polyester resins, polyether resins, epoxy resins, fluororesins, rosin resins and the like. Further, examples of binders for paints or inks include rubbers in addition to resins.
These resins are preferably emulsified, dispersed or dissolved in water. Therefore, carboxyl groups, sulfone groups and the like contained in resins can be neutralized.

Preferred resins include acrylic resins and polyester resins.
Resins such as melamine-based curing agents, isocyanate-based curing agents, and urethane dispersions can be used in combination as necessary. Furthermore, inorganic pigments, organic pigments, coloring pigments such as extender pigments, silane coupling agents, titanium coupling agents, dispersants, anti-settling agents, leveling agents, thickeners, defoaming agents, etc., which are generally added to paints May be combined. In order to improve the dispersibility in the paint, a surfactant may be added, and in order to improve the storage stability of the paint, an antioxidant, a light stabilizer, and a polymerization inhibitor may be added. may

Examples of coloring pigments include phthalocyanine, quinacridone, isoindolinone, perylene, azo lake, iron oxide, chrome, carbon black, titanium oxide, pearl mica, and the like.

Containment of the composite metal pigment composition according to the first invention of the present application, or the composite metal pigment composition produced by the manufacturing method of the second or third invention of the present application, in the water-based paint or water-based ink (resin composition) Although the amount is not limited, it is usually 0.1 to 30% by mass, preferably 1 to 20% by mass. When this content is 0.1% by mass or more, a high decorative (metallic) effect can be obtained. In addition, when the content is 30% by mass or less, it is possible to prevent the properties of the water-based paint or water-based ink, such as weather resistance, corrosion resistance, and mechanical strength, from being impaired.

The content of the solvent is not particularly limited, but may be 20 to 200% by mass with respect to the binder content. When the content of the solvent is within this range, the viscosity of the paint or ink can be adjusted within an appropriate range, and handling and film formation can be facilitated.

There are no particular restrictions on the method of coating with a water-based paint or the like, or the method of printing. For example, various coating methods or printing methods can be appropriately employed in consideration of the form of the water-based paint, the surface shape of the material to be coated, and the like. The coating method includes, for example, a spray method, a roll coater method, a brush coating method, a doctor blade method and the like. Examples of printing methods include gravure printing and screen printing.

A coating film formed of a water-based paint or the like may be formed on an undercoat layer or an intermediate coat layer formed by electrodeposition coating or the like. Moreover, if necessary, a topcoat layer or the like may be formed on the coating film formed of a water-based paint or the like.

In the case of these layer structures, each coating film layer may be coated, and the next coating film layer may be coated after curing or drying. The next coating layer may be applied without drying. A water-based paint or the like containing the composite metal pigment composition according to the first invention of the present application, or the composite metal pigment composition produced by the production method of the second invention or the third invention of the present application exhibits good mirror-like luster. In terms of obtaining a durable coating film, it is preferable to employ a method including a step of forming a coating film layer with a water-based paint or the like after coating and curing or drying the base coating film layer.
The curing method of the coating composition in each coating layer may be heat curing or normal temperature curing. Moreover, the drying method of the coating composition of each coating film layer may be, for example, using hot air or natural drying at room temperature.

Although the thickness of the coating film layer formed by water-based paint or the like is not particularly limited, it is generally preferably about 0.5 to 100 μm, more preferably about 1 to 50 μm. When the thickness of the coating film layer is 0.5 μm or more, the effect of hiding the substrate by the ink or paint can be sufficiently obtained. In addition, when the thickness of the coating film layer is 100 μm or less, drying becomes easy, and the occurrence of defects such as popping and sagging can be suppressed.

The composite metal pigment composition of the first invention of the present application, the composite metal pigment composition obtained by the production method of the second or third invention of the present application, and the coating film or the like obtained using the same have excellent design properties, gloss, and texture. Since it has a high level of stability in water-based paints, it has various applications in which metallic pigments have traditionally been used, such as paints, inks, and resin kneading agents, more specifically automobile bodies, automobile repair materials, and automobile parts. , household appliances, etc., plastic parts, PCM paints, highly weather-resistant paints, heat-resistant paints, anti-corrosion paints, ship bottom paints, offset printing inks, gravure printing inks, screen printing inks, etc.

The present invention will be described in greater detail below with reference to examples, but it should be noted that these examples are merely illustrative and the present invention is not limited by the description of these examples.

Example 1
Commercially available aluminum paste (manufactured by Asahi Kasei Corporation, trade name “GX-3100 (average particle diameter 11 μm, volatile content 74%)” was added to a 1 m ² reaction vessel having a diameter of 1 m and an anchor-type stirring blade with a blade diameter of 1 m. ) was added to 135 kg of 465 kg of methoxypropanol (hereinafter abbreviated as “PM”), the mixture was stirred with a stirring blade at 100 rpm, and 10 L/min of the dispersion extracted from the bottom of the reaction tank was poured from the top of the reaction tank. The aluminum paste was evenly dispersed in the PM with external circulation. In the external circulation, an ultrasonic wave of 500 W was applied for 1 minute in the middle of the flow channel to improve the dispersibility of the particles.
Next, a solution obtained by dissolving 1 kg of lintungstomolybdic acid (H ₃ PW ₆ Mo ₆ O ₄₀ ) hydrate in 5 kg of methoxypropanol was gradually added, and the mixture was stirred for 1 hour while maintaining the slurry temperature at 40°C. During the reaction, external circulation was continued while applying ultrasonic waves.
After that, 10 kg of tetraethoxysilane was added as an organosilicon compound, and then 10 kg of 25% aqueous ammonia and 200 kg of purified water were added over 3 hours. After that, 1.3 kg of methyltrimethoxysilane was added as a silane coupling agent and stirred for 2 hours. During the reaction, external circulation was continued while applying ultrasonic waves. After completion of the reaction, the slurry was filtered under pressure after cooling.
After thoroughly washing the filtered slurry with a mixed solution of isopropanol (hereinafter abbreviated as “IPA”)/PM:3/2 to replace the contained solvent, pressure filtration was performed again, and ventilation was performed to remove mainly IPA. Volatilization yielded a composite aluminum pigment composition with a non-volatile content of 90%. The water content in the IPA/PM mixed solvent used here was 200 ppm, and dry air with a dew point of -40°C was used for pressure filtration and ventilation.

Example 2
In the same manner as in Example 1 except that the aluminum paste was changed to (manufactured by Asahi Kasei Corporation, trade name "GX-4100 (average particle size 10 μm, volatile content 74%)"), a composite aluminum pigment composition with a nonvolatile content of 90%. got stuff

Example 3
In the same manner as in Example 1 except that the aluminum paste was changed to (manufactured by Asahi Kasei Corporation, trade name "FD-5090 (average particle size 9 μm, volatile content 75%)"), a composite aluminum pigment composition with a nonvolatile content of 85%. got stuff

Example 4
The reaction was carried out in the same manner as in Example 1. After the reaction was completed, the slurry was filtered after cooling, and washing and filtration were repeated three times with an equal amount of PM to obtain a paste with a non-volatile content of 50%. Then, the solvent was volatilized under reduced pressure at room temperature to increase the non-volatile content by 10%, and then the pressure was released to mix the paste so as to make it uniform, sealed and left for 12 hours. This operation was repeated twice to obtain a pasty composite aluminum pigment composition having a non-volatile content of 90%.

Example 5
A composite aluminum pigment composition having a non-volatile content of 90% was obtained in the same manner as in Example 1, except that an IPA/PM mixed solvent with a moisture content of 2000 ppm was used.

Comparative example 1
Commercial aluminum paste (manufactured by Asahi Kasei Corporation, trade name "GX-3100 (average particle size 11 μm, non-volatile content 74%)") 465 kg of PM was added to 135 kg and dispersed slurry was stirred, and lintungstomolybdic acid ( H ₃ PW ₆ Mo ₆ O ₄₀ ) hydrate 1 kg dissolved in PM 5 kg was gradually added, and the mixture was stirred for 1 hour while maintaining the slurry temperature at 40°C. After cooling, the slurry was filtered to obtain a composite aluminum pigment composition having a non-volatile content of 60%.

Comparative example 2
Examples except that the step after the reaction was completed and filtered was changed to a step of transferring the aluminum pigment composition to another container and removing the solvent for 1 hour under reduced pressure while heating to 50° C. while standing still. A composite aluminum pigment composition having a non-volatile content of 80% was obtained in the same manner as in Example 1.

Comparative example 3
A composite aluminum pigment composition having a non-volatile content of 80% was obtained in the same manner as in Example 1, except that the step after the reaction was completed and filtered was changed to a step of desolvating by pressing with a filter press.

(Evaluation of composite metal pigment composition)
Average particle size: _D50
The average particle size (D ₅₀ ) of the composite particles (silicon oxide-coated aluminum particles) in the composite aluminum pigment compositions obtained in the above Examples/Comparative Examples was measured using a laser diffraction/scattering particle size distribution analyzer (LA- 300/manufactured by Horiba, Ltd.).
Isopropanol was used as the measurement solvent.
The measurement was carried out according to the equipment instruction manual, but as a point to note, after performing ultrasonic dispersion for 2 minutes as a pretreatment on the composite metal pigment composition as a sample, it was put into a dispersion tank and adjusted to an appropriate concentration. After confirming dispersion, measurement was started.
After the measurement was finished, the _D50 was calculated by the instrument's software and displayed automatically.

Solid content concentration 10 g of the composite aluminum pigment composition obtained in each of the above examples/comparative examples was heated at 105 ° C. for 3 hours to volatilize the volatile matter, and then the mass was measured. asked for a percentage.

Residue After dispersing 50 g of the composite aluminum pigment composition obtained in each of the above Examples/Comparative Examples with a spatula in 1000 ml of mineral spirits, it was filtered through a 200-mesh nylon net (manufactured by NBC), and the residue was removed with acetone. After thorough washing and drying at 105° C. for 10 minutes, the mass was measured, and the ratio was determined as the mass of the residue.

(Evaluation of paint and coating film)
Using the composite aluminum pigment compositions obtained in the above Examples and Comparative Examples, water-based metallic paints were prepared with the following compositions, and the paints and coating films obtained therefrom were evaluated by the following methods. The results are shown in Table 1.
A water-based metallic paint was prepared having the following ingredients.
- Composite aluminum pigment composition: 12.0 g as non-volatile matter
・Methoxypropanol: 18.0 g
- Polyoxyethylene lauryl ether (nonionic surfactant, manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name "Marpon L5"): 6.0 g
・ Purified water: 12.0 g
・Water-soluble acrylic resin (*1): 110.0 g
・Melamine resin (*2): 18.0 g
*1: Almatex WA911 manufactured by Mitsui Chemicals, Inc.
*2: Cymel 350 manufactured by Nippon Cytec Industries Co., Ltd.
After mixing the above components, the pH was adjusted from 7.7 to 7.8 with dimethylethanolamine, and the viscosity was adjusted from 650 to 750 mPa s with a carboxylic acid thickener and purified water (Brookfield viscometer, No. 3 low, 60 rpm, 25° C.).

Using the water-based metallic paint thus prepared, the following evaluations were carried out.
・Evaluation 1 (storage stability (gas generation))
200 g of the water-based metallic paint prepared according to the above recipe was collected in a flask, and the accumulated hydrogen gas generation amount was measured in a constant temperature water bath at 60° C. for up to 24 hours. Based on the amount of generated gas obtained, evaluation was made according to the following criteria and used as an index of storage stability in the paint.
○: Less than 2 ml △: 2 or more and less than 10 ml ×: 10 ml or more and less than 50 ml XX: 50 ml or more

・Evaluation 2 (coating film evaluation)
The water-based metallic paint prepared according to the above formulation was air-sprayed onto a 12 cm × 6 cm intermediate coated steel plate (manufactured by Miki Coating Co., Ltd.) to a dry film thickness of 6 μm, and pre-dried at 90° C. for 10 minutes. After that, an organic solvent type top coat paint having the following composition was dispersed with a spatula for 3 minutes, then the paint viscosity was adjusted to 20.0 seconds with a Ford cup No. 4, and the dry film thickness was 20 μm. It was spray-coated and dried at 140° C. for 30 minutes to prepare a coated plate, which was subjected to the following evaluations.
(Composition of organic solvent-based topcoat paint)
・ Acrylic 44-179 (manufactured by DIC, acrylic clear resin) 141 g
・Super Beckamin J-820 (manufactured by DIC, melamine resin) 35.3 g
・123.5 g of toluene

2-i (paint film)
The number of pimples on the entire surface of the topcoat coating film of the obtained coated plate was counted and evaluated according to the following indices.
〇: No visible particles △: Less than 10 particles ×: More than 10 particles

2-ii (luminance)
The obtained coated plate was evaluated using a laser type metallic feeling measuring device Alcorp LMR-200 manufactured by Kansai Paint Co., Ltd. The optical conditions are a laser light source with an incident angle of 45 degrees and a light receiver at receiving angles of 0 degrees and -35 degrees. As a measurement value, the IV value was obtained at an acceptance angle of −35 degrees at which the maximum light intensity is obtained, excluding the light in the specular reflection region reflected on the coating film surface among the laser reflected light. The IV value is a parameter proportional to the intensity of specularly reflected light from the coating film, and represents the magnitude of light luminance.
From the obtained IV value, evaluation was made based on the following criteria.
○: The width of decrease from the reference (Comparative Example 1) was less than 20.
Δ: The range of decrease from the standard (Comparative Example 1) was 20 or more and less than 40. ×: The range of decrease from the standard (Comparative Example 1) was 40 or more.

2-iii (concealability)
The prepared water-based metallic paint was applied on a polyethylene terephthalate sheet (PET sheet) with a 2 mil applicator so that the dry film thickness was 15 μm, and dried at 140° C. for 30 minutes.
○: Equivalent to slightly lower than the reference (Comparative Example 1).
Δ: slightly lower than the reference (Comparative Example 1).
x: Significantly lower than the reference (Comparative Example 1).

(Evaluation of Aggregation and Deformation of Composite Particles)
In order to make it easier to determine the aggregation state of particles, etc., paint was prepared under the same conditions except that the amount of aluminum paste in the paint formulation used to prepare the coated plate in Evaluation 2 was reduced to 1/10, and evaluated. A coated plate was produced under the conditions of 2.
The coated plate was cut into 1 cm squares using a shearing machine.
Using an ion milling device (manufactured by JEOL / IB-09010CP), the obtained coating film cross section is set so that ion beam irradiation can be performed up to a portion 20 μm away from the coating film cross section. Polished cross-sectional samples were prepared.
The cross section of the resulting coating film (coated plate) was observed with an FE-SEM (manufactured by HITACHI/S-4700) to observe the overlapping state of the particles and the deformation state of the particles, and evaluated according to the following procedure.

Ratio of primary particles (aggregated state)
First, observations were made at a magnification of about 1000 to 3000 when the degree of overlapping of particles could be easily determined. When the degree of overlap could not be determined by this magnification, the degree of overlap was evaluated by appropriately changing the magnification. In this observation method, the observation was made at a maximum magnification of about 30000 times. A plurality of fields of view were observed from the cross section of the same sample piece so that the number of observed particles was 500 or more.
In addition, when it is difficult to determine aggregation because the particles are close to each other, it is determined that there is no aggregation if the length of the contact portion between the particles is 1/4 or less of the particle diameter of the smaller particle (the one with the shorter major axis), When it was larger than 1/4, it was determined that there was aggregation.

Percentage of bent particles (deformed state)
The degree of deformation of the particles was observed at a magnification of about 1000 to 3000 when the deformation was easily discernible. When the deformation could not be determined by this magnification, the degree of deformation was evaluated by appropriately changing the magnification. In this observation method, the observation was made at a maximum magnification of about 30000 times. A plurality of fields of view were observed from the cross section of the same sample piece so that the number of observed particles was 500 or more. Deformation was determined when the shortest distance between both ends of the particle was 0.8 times or less the length of the particle.

Average particle thickness of metal particles Using the FE-SEM image (10,000 times) obtained by the above acquisition procedure and the image analysis software Win Roof version 5.5 (manufactured by MITANI CORPORATION), the thickness of the particles in the cross section of the aluminum particles. Measurement and calculation of average thickness were performed.
Display the FE-SEM image for measuring the thickness of the particles in the cross section of the aluminum particles, select the ROI line, align the ROI line with the 5 μm scale of the image, and set by entering the length and unit from Register/Change. did.
Next, an image in which the thickness of the cross section of the aluminum particle should be measured was displayed, a rectangular ROI was selected, and binary processing was performed by matching the rectangular ROI to the cross section of the particle.
Next, after selecting the measurement item of the vertical chord length for measurement, measurement was executed, and the automatically measured value (vertical chord length value) by the image analysis software was displayed on the image.
Thus, 300 particles were selected using the above image analysis software Win Roof version 5.5, and the thickness and length of the cross section of the aluminum particles were automatically measured. Next, the thickness arithmetic mean value was calculated for 300 particles to obtain the average thickness t of the particles. The thickness uniformity of the aluminum particles is high, and the difference in thickness depending on the cut portion of the particles is small. Therefore, the influence of the difference in the cut portion of the grain on the measurement of the average grain thickness can be ignored.

Average particle thickness of composite particles, thickness of metal oxide coating For the coated plate used for acquiring the above FE-SEM image, an STEM (scanning transmission electron microscope) was used to measure the average thickness of the particle coating layer at a magnification of 200,000 times. Measured. If the surface of the coating layer has unevenness, the area of the coating layer is measured using image analysis software Win Roof version 5.5, and the area of the coating layer is divided by the perimeter of the coated particles. average thickness. When the particles are large, it is not always necessary to measure the area of the entire coating layer. The average thickness of the coating layer can be obtained with high accuracy. Also, since the average thickness of the coating layer is substantially uniform regardless of the particles, the average value was obtained for 10 particles. Also, the average thickness of the composite particles was calculated according to the following formula from the thickness of the particle coating layer and the average particle thickness of the metal particles obtained above.
Average particle thickness of composite particles = average particle thickness of metal particles + thickness of coating layer x 2

Table 1 shows the evaluation results. The composite metal pigment composition according to the present invention, which satisfies all of the above items (1) to (6) obtained in each example, has a high solid content and good stability as a paint. , less gas generation (having good storage stability), excellent brightness and hiding properties, and moreover, the coating film was effectively suppressed.

The composite metal pigment composition of the first invention of the present application, the composite metal pigment compositions obtained by the production methods of the second and third inventions of the present application, and the coating films obtained using them are suitable for low-VOC, water-based paints, etc. Since it combines excellent properties of the coating film such as storage stability, suppression of lumps, designability, concealability, etc. at a high level beyond the limits of conventional technology, paints, inks, resin kneading agents, etc. Various applications in which metallic pigments have been used, more specifically, automobile bodies, automobile repair materials, automobile parts, home appliances, etc., plastic parts, PCM paints, highly weather-resistant paints, heat-resistant paints, anti-corrosion paints, ship bottom paints, It can be suitably used in offset printing ink, gravure printing ink, screen printing ink, etc., and is highly applicable in various industrial fields such as the transportation machinery industry such as automobiles, the electrical and electronic industry such as home appliances, the paint industry, and the printing industry. have sex.

Claims (10)

A composite metal pigment composition comprising composite particles having a metal particle and a metal oxide coating formed on the surface thereof,
(1) the shape of the composite particles is scaly,
(2) the volume-based average particle diameter _D50 when the particle size distribution of the composite particles is measured with a laser diffraction particle size distribution meter is 1 to 30 μm;
(3) the composite particles have an average particle thickness of 20 to 300 nm,
(4) the composite metal pigment composition has a solid content concentration of 70 to 95% by mass;
(5) a hydrophilic solvent having a boiling point of 80 to 150° C. accounts for 80% by mass or more of the non-solid content of the composite metal pigment composition;
(6) The above-mentioned composite metal pigment composition, wherein the residue when the composite metal pigment composition is filtered through a 200-mesh filter is 0.1% by mass or less of the solid content. 2. The composite metal pigment composition according to claim 1, wherein the proportion of non-aggregated primary particles in said composite particles is 35% or more on a number basis. 3. The composite metal pigment composition according to claim 1, wherein the proportion of bent composite particles in said composite particles is 10% or less on a number basis. 4. A composite metal pigment composition according to any one of claims 1 to 3, wherein at least one layer in said metal oxide coating is a silicon compound-containing layer. The composite metal pigment composition according to any one of claims 1 to 4, wherein the metal oxide coating has an average layer thickness of 5 to 200 nm. 6. A composite metal pigment composition according to any preceding claim, wherein the metal particles comprise aluminum or an aluminum alloy. The composite metal pigment composition according to any one of claims 1 to 6, wherein the composite particles further have a coating layer containing at least one selected from metals, metal oxides, metal hydrates and resins. . A method for producing a composite metal pigment composition comprising the following steps 1) to 3),
1) a step of dispersing metal particles in a solvent; 2) a step of coating the metal particles with a metal oxide; The solvent in the step of washing, filtering, and volatilizing the solvent step 3) is a mixed solvent of two or more solvents that are compatible with each other and have a boiling point difference of 10 ° C. or more,
The above manufacturing method, wherein the solvent volatilization in step 3) is performed in a slurry state containing the composite particles and the solvent. A method for producing a composite metal pigment composition comprising the following steps 1) to 3),
1) a step of dispersing metal particles in a solvent; 2) a step of coating the metal particles with a metal oxide; Washing, Filtration, and Solvent Volatilization Process The above manufacturing method, wherein the solvent volatilization in step 3) is divided into three or more steps. 10. The production method according to claim 8 or 9, wherein the solvent has a moisture content of 10% by mass or less when the solvent is volatilized in step 3).