CN115216182B

CN115216182B - Composite metal pigment composition and method for producing same

Info

Publication number: CN115216182B
Application number: CN202210389121.4A
Authority: CN
Inventors: 藤本克宏; 杉本笃俊; 折笠智昭
Original assignee: Asahi Kasei Corp
Current assignee: Asahi Kasei Corp
Priority date: 2021-04-15
Filing date: 2022-04-13
Publication date: 2023-08-22
Anticipated expiration: 2042-04-13
Also published as: KR20220142928A; JP2022163850A; CN115216182A

Abstract

A composite metallic pigment composition and a method for producing the same, which have high non-volatile component (solid content) content and excellent dispersibility in a paint, and which can give a paint excellent in color tone, brightness, hiding property, etc., and excellent storage stability, and which have a high level of balance in characteristics. The composite metal pigment composition contains composite particles having metal particles and a metal oxide coating formed on the surface thereof, (1) the composite particles are scaly in shape, and (2) the volume-based average particle diameter D at the time of measuring the particle size distribution of the composite particles ₅₀ 1 to 30 [ mu ] m, (3) 20 to 300nm in average particle thickness of composite particles, (4) 70 to 95% by mass of solid content concentration of the composition, (5) 80% by mass or more of a solvent having hydrophilicity and a boiling point of 80 to 150 ℃ which is not less than 80% by mass of non-solid content of the composition, and (6) 0.1% by mass or less of residue of the composition when filtered by a 200-mesh filter.

Description

Composite metal pigment composition and method for producing same

Technical Field

The present invention relates to a composite metal pigment composition containing composite particles having metal particles and oxidized metal coating formed on the surfaces thereof, and more particularly, to a composite metal pigment composition which effectively suppresses aggregation, deformation, etc. of composite particles while reducing the amount of Volatile Organic Compounds (VOC), and which is used for storage stability in low VOC, aqueous paints, etc., suppression of particle generation, excellent properties of coating film such as designability, concealment, etc., and the like, and forms a balance at a high level, and a method for producing the same.

Background

Conventionally, metallic pigments have been used for metallic paints, printing inks, plastic kneading, and the like in order to obtain metallic cosmetic effects.

In recent years, in the paint field, as a countermeasure for saving resources, improving the working environment, and making pollution free, there has been an increasing need for conversion of aqueous paints with a small amount of organic solvents. In order to improve the stability of metallic pigments in aqueous paints, for example, pigments using composite particles in which metallic particles are covered with an oxidized metal such as amorphous silica have been proposed. Further VOC reduction is also required for such aqueous paints. In order to reduce VOC, it is effective to improve the content of non-volatile components (solid components) in the production process, and if the filtration process is performed by strong centrifugation, pressurization under strong pressure, and filtration, metal particles such as aluminum deform or aggregate, and further, defects occur in the oxide metal coating such as silica, which may deteriorate the water resistance and the storage stability. In addition, the non-volatile content can be improved by volatilizing the solvent by heating and depressurizing, but at this time, the surface is dried in advance and the particles adhere to each other and aggregate, and thus dispersion into the solvent or water cannot be achieved without aggregation. In this way, the conventional method has been used to improve the non-volatile content of the composite metal pigment composition, and there has been a strong demand for solving the problems of poor dispersibility, inability to exhibit a desired color tone, poor storage stability, and the like at the time of paint production.

For example, patent document 1 describes providing a PVD metallic effect pigment in the form of powder or in a highly concentrated form, and describes that the PVD pigment powder does not substantially aggregate, and has a good redispersibility. However, aggregation after redispersion and the like were not evaluated directly, and dispersibility in an aqueous solvent was not reported.

Patent document 2 describes that, in the production of a coated aluminum effect pigment, suction filtration is performed by a buchner funnel, and that an aqueous paint system is formed using the aluminum effect pigment, but no report is made on the good dispersibility.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2017-533982

Patent document 2: japanese patent application laid-open No. 2013-518948

Disclosure of Invention

Problems to be solved by the invention

In view of the limitations of the prior art described above, an object of the present invention is to provide a composite metal pigment composition having a high nonvolatile content (solid content) and excellent dispersibility in a paint, particularly an aqueous paint, and to provide a paint, particularly an aqueous paint, which can form a coating film excellent in color tone, brightness, concealing properties, and the like and is excellent in storage stability, and which is balanced at a high level, and a method for producing the same.

Solution for solving the problem

As a result of intensive studies, the present inventors have found that the above problems can be solved by using a specific hydrophilic solvent as a solvent constituting a composite metal pigment composition and/or by volatilizing the solvent under specific conditions in the production of the composite metal pigment composition, and have completed the present application.

That is, the application 1 and various modes thereof are as follows.

[1] A composite metallic pigment composition containing composite particles having metallic particles and a metal oxide coating formed on the surfaces thereof,

(1) The composite particles are in the shape of scales,

(2) Measuring the volume-based average particle diameter D of the composite particles in the particle size distribution by a laser diffraction type particle size distribution meter ₅₀ Is in the range of 1 to 30 mu m,

(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 to 95 mass%,

(5) A solvent having a hydrophilic property and a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid component of the composite metal pigment composition,

(6) The residue obtained when the above-mentioned composite metal pigment composition was filtered through a 200-mesh filter was 0.1% by mass or less of the solid content.

[2] The composite metal pigment composition according to [1], wherein the ratio of the primary particles which are not aggregated in the composite particles is 35% or more based on the number.

[3] The composite metal pigment composition according to [1] or [2], wherein the ratio of the curved composite particles in the composite particles is 10% or less based on the number.

[4] The composite metal pigment composition according to any one of [1] to [3], wherein at least 1 layer of the oxidized metal coating is a silicon-containing compound layer.

[5] The composite metal pigment composition according to any one of [1] to [4], wherein the average layer thickness of the oxidized metal coating is 5 to 200nm.

[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 metallic pigment composition according to any one of [1] to [6], wherein the composite particles further have: a coating layer containing at least one selected from the group consisting of a metal, a metal oxide, a metal hydrate, and a resin.

Further, applications 2 and 3 and various modes thereof are as follows.

[8] A method for producing a composite metallic pigment composition, comprising the following steps 1) to 3),

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal,

3) Washing, filtering and volatilizing the composite particles having the metal particles and the oxidized metal coating formed on the surface thereof obtained in the step 2),

the solvent in the step 3) is a mixed solvent of 2 or more solvents which are compatible with each other and have a boiling point difference of 10 ℃ or more,

the solvent volatilization in the step 3) is performed in a state of a slurry containing the composite particles and the solvent.

[9] A method for producing a composite metallic pigment composition, comprising the following steps 1) to 3),

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal,

the solvent volatile in step 3) is performed in 3 stages or more.

[10] The production method according to [8] or [9], wherein the solvent in the step 3) has a water content of 10% by mass or less when the solvent is volatilized.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present application, a novel composite metallic pigment composition which is not available in the prior art can be obtained.

The composite metallic pigment composition of the application 1 can effectively suppress aggregation, deformation, etc. of composite particles while reducing the amount of Volatile Organic Compounds (VOC), and can form a balance at a high level by exceeding the limits of the prior art, for example, excellent characteristics of a coating film such as storage stability, suppression of particles, design property, and hiding property for use in low VOC, aqueous coating materials, etc.

According to the production methods of the application 2 and 3, it is possible to efficiently produce a composite metal pigment composition which is capable of reducing the amount of Volatile Organic Compounds (VOCs) and effectively suppressing aggregation, deformation, etc. of composite particles, and which is used for a low VOC, an aqueous coating material, etc. and which is balanced at a high level by exceeding the limits of the prior art in terms of excellent properties of a coating film such as storage stability, particle suppression, design property, concealing property, etc.

Detailed Description

The present application will be described below with reference to exemplary or preferred embodiments, but the present application is not limited to these embodiments. These embodiments can be freely combined within the scope of the application as defined by the appended claims, provided they are not explicitly stated.

The application 1 st application is a composite metallic pigment composition containing composite particles having metallic particles and a metal oxide coating formed on the surfaces thereof,

(1) The composite particles are in the shape of scales,

(3) The average particle thickness of the composite particles is 20-300 nm,

Composite particles constituting composite metallic pigment composition

The composite metal pigment composition of the application 1 contains composite particles having metal particles and a metal oxide coating formed on the surface thereof.

That is, in the present specification, the term "composite metal pigment composition" contains composite particles having metal particles and oxidized metal coatings formed on the surfaces thereof as an essential component, and also contains a specific non-solid component.

The composite metallic pigment composition of the application 1 may contain other components, for example, an organic treating agent, a solvent containing water and/or a hydrophilic solvent.

Metal particles

The composite particles constituting the composite metallic pigment composition of the application 1 comprise metallic particles and a metal oxide coating formed on the surfaces thereof. That is, 1 or more metal oxide layers are formed on the surface of the metal particles which become the core of the composite particle. The oxidized metal coating typically has a layered structure.

The material of the metal particles (core particles) constituting the composite particles is not particularly limited, and may be any of metals used as known or commercially available metal pigments, such as aluminum, aluminum alloy, zinc, iron, magnesium, nickel, copper, silver, tin, chromium, stainless steel, and the like. In the present specification, the metal of the metal particles constituting the composite particles includes not only a simple metal but also an alloy or an intermetallic compound.

The metal particles may be used alone or in combination of 2 or more.

The metal particles in the application 1 preferably contain aluminum or an aluminum alloy, and more preferably 95 mass% or more of the metal particles are composed of aluminum element.

The average particle diameter of the metal particles is not particularly limited, and D in the particle size distribution of the composite particles to be described later is preferably achieved ₅₀ Is a particle size of the particles. That is, it is preferable that D is measured in the composite particles by a laser diffraction particle size distribution meter when the volume distribution is measured ₅₀ In the range of 1 to 30 μm, or in order to easily form the D ₅₀ Is set in such a manner that the volume average particle diameter (D ₅₀ )。

The average particle diameter of the metal particles can be controlled by appropriately adjusting the particle diameter of the raw material atomized metal powder (for example, aluminum powder) or the like, the mass per 1 grinding ball when the ball mill is used, the rotation speed of the grinding apparatus, the degree of sieving and press filter, and the like in the step of grinding and sieving/filtering the raw material atomized metal powder or the like using the ball mill or the like.

The thickness and shape of the metal particles are not particularly limited, and scale-like (flake-like) particles having an average particle thickness of 10 to 300nm are preferable. Thus, the composite particles constituting the composite metallic pigment composition according to the application 1 can easily have a scaly shape, and as a result, a high hiding power and the like can be obtained more reliably.

The average thickness of the metal particles is preferably a thickness that can achieve an average thickness of the composite particles described later, and more specifically, is preferably 10 to 300nm. Thus, aggregation and deformation of the composite particles are effectively suppressed, and excellent design properties, gloss, suppression of particle generation, stability in aqueous paint and the like in the coating film are easily achieved. The average thickness of the metal particles is preferably 15 to 250nm, more preferably 20 to 200nm from the above viewpoint.

The average particle thickness of the metal particles can be measured by a method known in the art, for example, by forming a coating film using a metal pigment composition containing composite particles having metal particles and a metal oxide coating formed on the surface thereof, obtaining an FE-SEM image (field emission scanning electron microscope image) of a cross section thereof, and performing image analysis. More specifically, the measurement can be performed by the method described in the examples of the present application.

The ratio of the diameter to thickness of the flaky metal particles (the shape factor obtained by dividing the average particle diameter by the average thickness) is preferably 30 to 1500, more preferably 50 to 1000, particularly preferably 80 to 700. By setting the ratio of the diameter to the thickness of the metal particles to 30 or more, a higher brightness can be obtained. In addition, since the ratio of the diameter to the thickness of the metal particles is 1500 or less, the mechanical strength of the sheet is maintained, and a stable color tone can be obtained.

Average thickness and volume basis of metal particles D ₅₀ Similarly, the particle diameter of the raw material atomized metal powder (for example, aluminum powder) can be controlled by appropriately adjusting the mass of each 1 grinding ball when using a ball mill, the rotation speed of the grinding apparatus, the degree of screening and press filter, and the like in the steps of grinding the raw material atomized metal powder (for example, aluminum powder) using a ball mill or the like and screening/filtering.

The metal particles do not necessarily need to be composed of only metal, and particles having surfaces covered with metal, such as particles of synthetic resin, inorganic particles of mica, glass, or the like, may be used as long as the effect of the application 1 is not impaired. In the application 1, particles containing aluminum or an aluminum alloy are preferable from the viewpoints of high weather resistance, small specific gravity, easy availability, and the like.

The metal particles constituting the composite particles are particularly preferably aluminum flakes which are usually used as a metal pigment. Aluminum flakes having surface properties, particle diameters, and shapes required for metallic pigments, such as surface gloss, whiteness, and brightness, are suitable. Aluminum flakes are generally commercially available in the paste state. The paste-like aluminum flakes can be used as such, or pre-formedThe surface fatty acid is first removed by an organic solvent or the like and used. In addition, the volume average particle diameter (D ₅₀ ) An aluminum vapor deposited foil having an average thickness (t) of from 3 to 20 μm and from 10 to 110 nm.

Oxide metal coating

The composite particles constituting the composite metallic pigment composition of the application 1 have a metal oxide coating formed on the surface of the metal particles.

The metal oxide is a film formed by a layer containing metal oxide, and may be formed on the entire surface of the metal particles or only a part of the surface. From the viewpoints of water resistance, storage stability when used in a paint, and the like, it is preferably formed on all surfaces.

The metal oxide coating may be entirely made of metal oxide, or may be made of metal oxide only in part and contain a component other than metal oxide.

The oxidized metal constituting the oxidized metal coating is a compound whose constituent elements contain oxygen and at least one metal element.

Accordingly, the metal oxide may be a narrow-definition metal oxide in which only oxygen and at least one metal element are included as its constituent elements, but as long as the constituent elements include oxygen and at least one metal element, elements other than the oxygen and the metal element may be included in the constituent elements, and for example, hydroxide, oxide hydrate, oxynitride, or the like of the metal may be used. In addition, the compound may be a compound containing an organic group.

The metal oxide may be a so-called single oxide of only 1 kind of metal element as a constituent element, or may be a composite oxide of 2 or more kinds of metal elements as constituent elements.

The at least one metal element as a constituent element of the oxidized metal may be a typical metal or a transition metal. Furthermore, the metal may be a so-called semi-metal element. Among them, silicon is particularly preferable as the metal oxide constituting the metal oxide coating.

Specific examples of the metal oxide 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, oxide hydrates thereof, hydroxides thereof, and mixtures thereof. Among them, silicon oxide, aluminum oxide, and mixtures thereof, and oxide hydrates and hydroxides thereof are preferably used. Silicon oxides such as silicon oxide, silicon hydroxide, and/or silicon oxide hydrate are particularly preferably used.

The use of a silicon oxide for the metal oxide coating is particularly advantageous from the viewpoints of achieving good storage stability in the aqueous coating material, improving water resistance at the time of forming a coating film, suppressing gas generation, and the like.

The oxide metal covering generally forms a layer composed of a compound containing si—o-bonds (siloxane bonds) by using a silicon oxide for the oxide metal covering. Examples of such a layer include a layer containing at least one of a silane compound and a silicon oxide. As such a compound, a silane-based compound [ H ] is exemplified ₃ SiO(H ₂ SiO) _n SiH ₃ ](wherein n represents an arbitrary positive integer), siO may be exemplified ₂ 、SiO ₂ ·nH ₂ O (where n represents an arbitrary positive integer), and the like. These silane compounds and silicon oxides may be either crystalline or amorphous, and are particularly preferably amorphous. Therefore, as the layer containing silicon oxide (silicon dioxide or the like), for example, a layer containing amorphous silicon dioxide can also be suitably used.

The metal oxide coating using a silicon oxide may be a layer formed using an organosilicon compound (containing a silane coupling agent) as a starting material. In this case, the oxidized metal coating may contain an unreacted organosilicon compound or a component derived therefrom within a range that does not hinder the effect of the application 1. In a typical example of this case, the metal oxide coating can be formed by hydrolyzing an organosilicon compound.

The mass of the metal oxide coating layer when using a silicon oxide is not particularly limited, but is preferably 1 to 20 parts by mass, particularly preferably 2 to 15 parts by mass, relative to 100 parts by mass of the metal particles. The silicon content of the oxidized metal coating is 1 part by mass or more relative to 100 parts by mass of the metal particles, whereby the corrosion resistance, water dispersibility, stability, and the like of the composite metal pigment composition can be maintained high. The silicon content of the oxidized metal coating is 20 parts by mass or less relative to 100 parts by mass of the metal particles, whereby aggregation of the composite particles, a decrease in tone such as concealing property and metallic luster can be prevented.

The metal oxide coating of the composite particles contained in the composite metal pigment composition of the application 1 is particularly preferably hydrophilic. The composite particles are usually formed into a composite metal pigment composition in a form dispersed in an aqueous solvent (water or a mixed solvent containing water and an organic solvent), and in the case where the oxidized metal coating has a hydrophilic surface, the composite particles can be highly dispersed in such an aqueous solvent. Further, since an oxidized metal such as a silicon oxide (amorphous silica or the like) is extremely stable in an aqueous solvent, a composite metal pigment containing highly stable composite particles in an aqueous solvent can be provided. From this viewpoint, it is preferable that at least 1 layer, preferably the outermost layer, of the composite particles contained in the composite metal pigment composition of the application 1 is an oxidized metal coating film, and particularly preferably a silicon-containing compound layer (particularly a layer composed of a compound containing si—o bond). In the case where the composite particles have a coating layer composed of a plurality of layers because the metal oxide has excellent affinity with the metal particles, a metal oxide layer, particularly preferably a silicon-containing compound layer (particularly a si—o-based coating layer), may be formed separately from the outermost layer, particularly preferably a layer in contact with the metal particles, in addition to the metal oxide coating layer of the outermost layer.

The thickness of the oxidized metal coating of each composite particle is not particularly limited as long as the average particle thickness of the composite particles is in the range of 20 to 300nm as described above. The thickness of the oxidized metal coating is usually preferably in the range of about 5 to 200nm (particularly 10 to 100nm, further 20 to 70 nm). By the thickness of the oxidized metal coating being 5nm or more, a coating film having sufficient water resistance and suppressed generation of corrosion or discoloration of metal particles in the aqueous coating material can be obtained. On the other hand, the thickness of the metal oxide coating is about 200nm or less, and the brightness, the distinctness of image, and the hiding power of the coating film can be maintained at high levels.

The thickness of the silicon-containing compound layer when the silicon-containing compound layer is contained in the oxide metal coating of each composite particle is not particularly limited as long as the average thickness of the composite particles is in the range of 2 to 300nm, as will be described later. The thickness of the silicon-containing compound layer may be in the range of usually 5 to 200nm, particularly preferably 10 to 100nm, and further preferably 20 to 70nm from the viewpoint of the function of the layer.

Specific examples of the organosilicon compound that can be used in the present embodiment are described further below, but the organosilicon compound is not limited to these specific examples.

The organosilicon compound may contain at least one of organosilicon compounds represented by the following general formula (1), and at least one selected from so-called silane coupling agents represented by any one of the following general formulae (2), (3) and (4), and partial condensates thereof.

Si(OR ¹ ) ₄ (1)

(wherein R is ¹ Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ¹ In the case of 2 or more, the number may be the same in all, a part of the number may be the same, or the number may be different in all. )

R ² _m Si(OR ³ ) _4-m (2)

(wherein R is ² Is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms and optionally containing a halogen group, R ³ Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R is R ² And R is ³ R, which may be identical or different, R ² Or R is ³ In the case of 2 or more, the number may be the same in all, a part of the number may be the same, or the number may be different in all. M is more than or equal to 1 and less than or equal to 3. )

R ⁴ _p R ⁵ _q Si(OR ⁶ ) _4-p-q (3)

(wherein R is 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 and optionally containing a halogen group, R ⁶ Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R is R ⁴ 、R ⁵ Or R ⁶ In the case of 2 or more, the number may be the same in all, a part of the number may be the same, or the number may be different in all. P is more than or equal to 1 and less than or equal to 3, q is more than or equal to 0 and less than or equal to 2, and p+q is more than or equal to 1 and less than or equal to 3. )

R ⁷ _r SiCl _4-r (4)

(wherein R is ⁷ Is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms and optionally containing a halogen group, R ⁷ In the case of 2 or more, the number may be the same in all, a part of the number may be the same, or the number may be different in all. R is more than or equal to 0 and less than or equal to 3. )

R as formula (1) ¹ Examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, hexyl, octyl, and the like, and they may be branched or straight. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl are particularly preferred. In addition, 4R ¹ May be all the same, some the same, or all different.

Preferable examples of the organosilicon compound of the formula (1) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and the like. Among them, tetraethoxysilane is particularly preferable.

R as formula (2) ² Examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, and naphthyl groups, which may be branched or straight-chain, and may contain halogen groups such as fluorine, chlorine, and bromine. Of these, hydrocarbon groups having 1 to 18 carbon atoms are particularly preferable. In addition, R ² In the case of 2 or more, they may be all the same, some of them may be the same, or all of them may be different. R in the molecule ² In the formula (2), m=1 to 3, that is, 1 to 3, but more preferably m=1 or 2.

R as formula (2) ³ Examples of the hydrocarbon groups include methyl, ethyl, propyl and butyl groupsHexyl, octyl, etc., which may be branched or straight. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl are particularly preferred. In addition, R ³ In the case of 2 or more, they may be all the same, some of them may be the same, or all of them may be different.

As a preferable example of the organosilicon compound (silane coupling agent) of the formula (2), examples thereof include methyltrimethoxysilane, methyltriethoxysilane, methylttributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, trimethylmethoxysilane, trimethylethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltributoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltributoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldibutoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dioctyldimethoxysilane, dioctyldiethoxysilane, decyltrimethoxysilane, didecyldimethoxysilane, octadecyltrimethoxysilane, dioctadecyltrimethoxysilane, dioctadecyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyldiethoxysilane, diphenyldiethoxysilane, trifluorotriethoxysilane, trioctyl-3-fluorotridecyl-triethoxysilane, 3-fluorotridecyl-triethoxysilane, 3-chloropropyl tributoxy silane, and the like.

R as formula (3) ⁴ Examples of the reactive group capable of chemically bonding to other functional groups include vinyl, epoxy, styryl, methacryloxy, acryloxy, amino, ureido, mercapto, and polySulfide (polysulfide) groups, isocyanate groups, and the like.

In addition, R ⁴ In the case of 2 or more, they may be all the same, some of them may be the same, or all of them may be different. R in the molecule ⁴ In the formula (3), p=1 to 3, that is, 1 to 3, but more preferably p=1.

R as formula (3) ⁵ Examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, and naphthyl groups, which may be branched or straight-chain and may contain halogen groups such as fluorine, chlorine, and bromine. Of these, hydrocarbon groups having 1 to 18 carbon atoms are particularly preferable. In addition, R ⁵ In the case of 2 or more, they may be all the same, some of them may be the same, or all of them may be different.

R as formula (3) ⁶ Examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, hexyl, octyl, and the like, and they may be branched or straight. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl are particularly preferred. In addition, R ⁶ In the case of 2 or more, they may be all the same, some of them may be the same, or all of them may be different.

As preferable examples of the organosilicon compound (silane coupling agent) of the formula (3), vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyldiethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, N-methyl-3-aminopropyl-trimethoxysilane, N-2- (aminoethyl) -3-aminopropyl methyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl-triethoxysilane, N-3-aminopropyl-2- (aminopropyl) -amino-trimethoxysilane, N-2-aminopropyl-triethoxysilane, N-2-aminopropyl-3-aminopropyl-ethoxysilane, N-aminopropyl-2-aminopropylsilane, N-glycidoxylsilane, 3-glycidoxypropylsilane, and the following examples mentioned 3-triethoxysilyl-N- (1, 3-dimethyl-butylidene) propylamine, 3-ureidopropyltriethoxysilane, 3-mercaptopropyl methyldimethoxysilane, 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl-triethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyl triethoxysilane, and the like.

R as formula (4) ⁷ Examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, and naphthyl groups, which may be branched or straight-chain, and may contain halogen groups such as fluorine, chlorine, and bromine. Of these, hydrocarbon groups having 1 to 12 carbon atoms are particularly preferable. In addition, R ⁷ In the case of 2 or more, they may be all the same, some of them may be the same, or all of them may be different. R in the molecule ⁷ In the formula (4), r=0 to 3, that is, 0 to 3, but r=1 to 3 is more preferable.

Preferable examples of the organosilicon compound (silane coupling agent) of the formula (4) include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, octyldimethylchlorosilane, phenyltrichlorosilane, vinyltrichlorosilane, and tetrachlorosilane.

The organosilicon compound represented by the above general formula (1) may be used alone or in combination of 1 or more than 2. The silane coupling agent represented by any one of the general formulae (2), (3) and (4) may be used alone or in combination of 2 or more. When 2 or more kinds of silane coupling agents are used in combination, only 2 or more kinds of silane coupling agents represented by any one of (2), (3) and (4) may be used in combination, or different 2 or more kinds of silane coupling agents represented by the general formula may be used in combination.

The hydrolysate of the organosilicon compound and/or the condensate thereof is obtained by stirring and mixing the organosilicon compound and water in an amount necessary for the hydrolysis reaction with a hydrolysis catalyst. In this case, a hydrophilic solvent may be used as needed. Various conditions for the hydrolysis reaction (i.e., the reaction for forming the silicon-containing compound layer) are described later.

As a raw material for hydrolysis reaction and/or condensation reaction of a hydrolysate and/or condensation reactant of an organosilicon compound, an oligomer partially condensed in advance may be used.

The condensation reaction of the hydrolysate of the organosilicon compound may be carried out simultaneously with the hydrolysis reaction of the organosilicon compound, or may be carried out by a separate process and replacing the catalyst as needed. In this case, the temperature may be raised as needed.

Physical properties of composite particles and composite metallic pigment composition

The composite metal pigment composition according to the application 1 satisfies the following physical properties.

(1) The composite particles are in the shape of scales.

(2) Volume-based average particle diameter D in measurement of particle size distribution of composite particles by laser diffraction particle size distribution meter ₅₀ 1-30 μm.

(3) The average particle thickness of the composite particles is 20-300 nm.

The composite metal pigment composition according to the application 1 further satisfies the following conditions as a composition.

(4) The solid content concentration of the composite metal pigment composition is 70 to 95 mass%.

(5) The solvent having hydrophilicity and a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid component of the composite metal pigment composition.

(6) The residue of the composite metal pigment composition when filtered by a 200-mesh filter is 0.1% by mass or less of the solid content.

These physical properties are described below.

(1) The composite particles are in the shape of scales.

The composite particles contained in the composite metallic pigment composition according to the application 1 have a scale-like shape. The composite metal pigment composition according to the application 1 can effectively form a coating film having excellent properties such as high hiding power by containing the scaly composite particles.

The scaly composite particles tend to be easily deformed in the steps of stirring, separating, filtering, etc. at the time of production, and in particular, tend to be easily deformed by strong centrifugal separation, filtration under strong pressure, etc. for increasing the content of non-volatile components (solid components), but in the present application, the deformation of the scaly composite particles can be effectively suppressed while achieving a high content of non-volatile components (solid components).

The term "composite particles having a scaly shape" means that the particles have a shape having a ratio of height to thickness preferably falling within a numerical range described below.

The scaly composite particles can be produced by using scaly metal particles as a raw material or the like in the production of the composite particles. As such metal particles, for example, known or commercially available paste-like aluminum flakes can be used.

The scale-like composite particles contained in the composite metal pigment composition of the application 1 preferably have a ratio of diameter to thickness (shape factor obtained by dividing the average particle diameter by the average thickness) of 30 to 700. The composite particles have a ratio of 30 or more in diameter to thickness, and thus a higher brightness can be easily obtained. In addition, the composite particles have a ratio of the diameter to the thickness of 700 or less, so that the mechanical strength of the composite particles is maintained and a stable color tone is easily obtained. The aspect ratio is preferably 50 to 600, more preferably 80 to 500.

(2) Volume-based average particle diameter D in measurement of particle size distribution of composite particles by laser diffraction particle size distribution meter ₅₀ Is 1 to 30 mu m

Volume-based average particle diameter D in measurement of particle size distribution of composite particles by laser diffraction particle size distribution meter ₅₀ 1-30 μm. Thus, the aggregation and deformation of particles can be effectively suppressed, and a coating film formed using the composite metal pigment composition or an aqueous paint containing the same can achieve excellent design properties, gloss, suppression of particle generation, stability in an aqueous paint, and the like. D of the volume reference ₅₀ Also commonly referred to as median particle size.

From the viewpoints of obtaining excellent designability, gloss, suppression of particles, stability in aqueous coating materials, and the like, the volume-based D at the time of measuring the particle size distribution of composite particles by a laser diffraction particle size distribution meter ₅₀ Preferably from 2 to 25. Mu.m, particularly preferably from 3 to 20. Mu.m.

The term "composite particles" in the present physical property condition refers to an aggregate (aggregate) of a plurality of composite particles when the composite particles are aggregated/adhered.

Here, the volume-based D is measured by a laser diffraction particle size distribution meter when the particle size distribution of the composite particles is measured ₅₀ Refers to a particle diameter of 50% of the cumulative degree in the volume cumulative particle size distribution. The laser diffraction particle size distribution meter is not particularly limited, and may be, for example, "LA-300" (manufactured by horiba, inc.). As the measurement solvent, a hydrophilic solvent such as water, isopropyl alcohol, and methoxypropanol can be used. For example, the composite metal pigment composition containing the composite particles of the sample is subjected to ultrasonic dispersion for about 2 minutes as a pretreatment, and then put into a dispersion tank, and after confirming that the composition is properly dispersed, D can be measured ₅₀ 。

Volume-based D of composite particles constituting composite metallic pigment composition ₅₀ For example, in the step of grinding and sieving/filtering the raw material atomized metal powder (for example, aluminum powder) using a ball mill or the like, the particle diameter and the amount of the raw material atomized metal powder to be charged, the amount of the grinding solvent such as mineral spirits, the kind and the amount of the grinding aid, the mass and the amount of the grinding aid per 1 grinding ball when using the ball mill, the rotation speed of the grinding apparatus, the degree of sieving and the filter press, etc. may be appropriately controlled, and in the step of covering the metal oxide (and, if necessary, other covering layers), the pH, the concentration, the stirring temperature, the stirring time, the kind of the stirring apparatus, the power/degree of stirring (the kind and diameter of stirring wings, the rotation speed, the presence or absence of external stirring, etc.) and the like may be appropriately controlled.

In addition, although particle size tends to be large due to aggregation during the metal oxide coating treatment, particle size tends to be small, and color tone and masking properties tend to be small, and appearance of the coating film tends to be small.

(3) The average particle thickness of the composite particles is 20-300 nm

The composite particles contained in the composite metallic pigment composition of the application 1 have an average thickness of 20 to 300nm. Thus, in combination with the satisfaction of the above conditions (1) and (2), aggregation and deformation of the composite particles are effectively suppressed, and excellent designability, gloss, suppression of particle generation, stability in aqueous paint, and the like in the coating film can be achieved.

The average thickness of the composite particles is preferably 20 to 250nm, more preferably 20 to 200nm from the above viewpoint.

For the average thickness of the composite particles herein, the average particle thickness of the metal particles and the thickness of the oxidized metal coating can be measured separately, and calculated from them according to the following formula.

Average particle thickness of composite particles = average particle thickness of metal particles + thickness of oxidized metal cover 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, for example by STEM (scanning transmission electron microscopy). More specifically, the measurement can be performed by the method described in the examples of the present application.

Average thickness and volume basis D of composite particles contained in composite metallic pigment composition ₅₀ Similarly, the pretreatment of the raw material aluminum paste, the pH, concentration, stirring temperature, stirring time, type of stirring device, stirring at the time of hydrolysis of the raw material such as the organosilicon compound, and the like can be appropriately adjusted in the step of treating the raw material metal powder, the step of covering the oxidized metal such as the silicon compound layer (and other covering layers as needed), and the like And the power/degree (type and diameter of stirring wings, rotation speed, presence or absence of external stirring, etc.). In addition, although particle size tends to be large due to aggregation during the metal oxide coating treatment, particle size tends to be small, and color tone and masking properties tend to be small, and appearance of the coating film tends to be small.

(4) The solid content concentration of the composite metal pigment composition is 70-95 mass%

The solid content concentration of the composite metallic pigment composition of the application 1 is 70 to 95 mass%.

The composite metal pigment composition according to the application 1 can achieve a coating material which can achieve a low VOC (volatile organic compound) and can form a coating film having a good appearance by having a solid content concentration of 70 to 95 mass%. More specifically, the content of VOC such as solvent can be sufficiently reduced by the solid content concentration of 70 mass% or more, and therefore even when the paint is formed using the same, a paint in which the content of VOC is sufficiently reduced can be realized. On the other hand, when the solid content concentration is 95 mass% or less, uniform dispersion is easy at the time of forming a coating material, and generation of particles in a coating film and the like can be effectively suppressed.

The solid content concentration is preferably 75 to 95% by mass, more preferably 80 to 95% by mass, particularly preferably 85 to 95% by mass.

The solid content concentration of the composite metallic pigment composition is the mass ratio of the solid content (nonvolatile component) contained in the composite metallic pigment composition. The solid content concentration can be determined by measuring the mass of the composite metal pigment composition after a predetermined amount of the composite metal pigment composition is heated to volatilize the volatile component, and determining the ratio of the mass to the mass before heating. More specifically, the measurement can be performed by the method described in the examples of the present application.

The solid content concentration of the composite metal pigment composition can be suitably adjusted by removing volatile components such as a solvent used in the formation of the metal oxide film by dispersing the metal particles by filtration, volatilization, or the like during the production of the composite metal pigment composition.

In the application 1, in order to achieve a specific high solid content concentration, a low boiling point solvent that is easily removed by evaporation is preferably used. Such a low boiling point solvent may not be suitable for the dispersion of the metal particles and the formation of the oxidized metal coating film, and therefore, the solvent replacement of the lower boiling point solvent may be performed after the dispersion of the metal particles and the formation of the oxidized metal coating film.

The volatilization is also preferably performed stepwise, and for example, after the volatilization, the composite particles may be diffused into the solvent and the volatilization may be performed again.

Further, in order to achieve a high solid content concentration, it is also preferable to combine filtration and volatilization, and particularly preferable to carry out filtration to reduce the amount of volatile components and then volatilize.

The high solid content concentration can be achieved by removing the solvent or the like by centrifugation or filtration under relatively strong pressure, but it is noted that such an operation may cause aggregation and/or deformation of the scaly composite particles, and it may be difficult to achieve other conditions of the application 1, such as the average particle diameter D of the prescribed volume basis ₅₀ The specified residue amount.

In the application 1, when the specific solid content concentration is achieved, the production method of the application 2 and/or the production method of the application 3 is particularly preferably used in view of effectively preventing aggregation and deformation of the composite particles and sufficiently removing volatile components.

(5) 80% by mass or more of the non-solid content of the solvent-based composite metal pigment composition having a hydrophilic property and a boiling point of 80 to 150 DEG C

The solvent having a hydrophilic property and a boiling point of 80 to 150 ℃ (hereinafter also referred to as "specific solvent") accounts for 80 mass% or more of the non-solid component of the composite metal pigment composition of the application 1.

Since the specific solvent is easily volatilized at a boiling point of 80 to 150 ℃, extreme high temperature and pressure reduction are not required at the time of volatilization, and therefore, the specific solvent occupies 80 mass% of the non-solid components, and the non-solid components such as the solvent can be removed without aggregation and adhesion of the composite particles to each other, thereby improving the solid content.

Further, since the specific solvent is hydrophilic, it is easy to disperse the composite metallic pigment composition of the application 1 into water by the specific solvent accounting for 80 mass% of the non-solid component, and it is further easy to form a uniform aqueous coating material. In addition, the water in the composition is further easily removed by azeotropy or the like by being hydrophilic, and aggregation due to moisture can be further effectively suppressed.

The concept of a hydrophilic solvent is commonly understood among those skilled in the art, and for example, a solvent having a solubility in water of 20g/g or more at ordinary temperature may be preferably used as the hydrophilic solvent. In addition, a solvent having an sp value (solubility parameter) of 10.5 or more can be preferably used as the hydrophilic solvent.

The specific solvent is preferably 80 to 100% by mass, more preferably 85 to 100% by mass, and particularly preferably 90 to 100% by mass of the non-solid component of the composite metal pigment composition.

The amount (ratio) of the specific solvent can be appropriately adjusted by adjusting the composition of the solvent used in the production of the composite metallic pigment composition. The amount (ratio) of the specific solvent can be generally determined by the amount of each solvent used in the production of the composite metal pigment composition and the amount of each solvent removed, but when the steps such as filtration and volatilization at the time of production are complicated and difficult to calculate, the solvent can be extracted from the obtained composite metal pigment composition by using a solvent such as THF (tetrahydrofuran) or the like, and can be measured by using LC-MS (liquid chromatography mass spectrometer) or the like.

Preferable examples of the specific solvent include methoxypropanol, isobutanol, n-butanol, isopropanol, and n-propanol.

These specific solvents may be used only in 1 kind or in combination of 2 or more kinds.

The residue obtained when the composite metal pigment composition of the application 1 is filtered by a 200-mesh filter is 0.1% by mass or less of the solid content.

The pore size of the 200 mesh filter is about 74 μm, so that the average particle diameter D for volume basis ₅₀ Composite particles having an average particle thickness of 20 to 300nm and 1 to 30 μm pass through a 200-mesh filter in a large proportion if the particles do not adhere to each other and aggregate. Therefore, the residue of the composite metal pigment composition when filtered by a 200-mesh filter is composite particles in which particles adhere to each other and aggregate, and the ratio of the composite particles to the solid content is preferably low,

Since the residue obtained when the composite metal pigment composition of the application 1 is filtered by a 200-mesh filter is 0.1% by mass or less of the solid content, adhesion and aggregation of particles are effectively suppressed, and the composite metal pigment composition can be dispersed in a solvent or water to form a coating material in which aggregation is suppressed, and can form a coating film excellent in appearance such as effective suppression of particles.

The amount of the residue obtained when the filter is used for filtration with a 200-mesh filter is preferably 0.05% by mass or less, more preferably 0.01% by mass or less, and particularly preferably 0.005% by mass or less of the solid content.

The amount of the residue obtained when the composite metal pigment composition is filtered by a 200-mesh filter can be well dispersed in a solvent, and then the residue is filtered by a 200-mesh filter, and the dry mass of the residue is measured, and the ratio of the residue to the solid content can be determined from the dry mass and the mass of the solid content in the composite metal pigment composition. More specifically, the measurement can be performed by the method described in the examples of the present application.

The amount of residue at the time of filtration with a 200 mesh filter can be reduced by suppressing adhesion and aggregation of composite particles by various methods described in the specification of the present application. In particular, the use of a large amount of the above specific solvent is effective for reducing the amount of residue. In addition, according to the production method of the application 2 and/or the application 3, the volatile components are removed while effectively preventing aggregation and deformation of the composite particles, and the amount of residue is also effectively reduced.

Composite particlesPreferred physical Properties of the pellet

The composite metal pigment composition according to the application 1 preferably has a composite particle comprising part or all of the following physical properties, characteristics, and the like, in addition to the physical properties (1) to (3).

The ratio of non-aggregated primary particles in the composite particles is more than 35% based on the number

In the composite metal pigment composition of the present embodiment, the ratio of the non-aggregated primary particles to the total composite particles contained in the composite metal pigment composition is preferably 35% or more based on the number of particles. A ratio of the primary particles of 35% or more means that aggregation of each particle is suppressed, and not only the primary particles, but also the aggregated particles are aggregated to a smaller extent. Thus, a coating film formed using the composite metallic pigment composition exhibits excellent design, gloss, suppression of particle generation, and at the same time, further improvement of stability in aqueous paints and the like is facilitated.

In addition, since the aggregation of the particles is suppressed, the stirring for dispersion is gentle enough, and thus the deformation of the particles due to the stirring can be greatly reduced.

From the viewpoint of promoting the above-described effects, the ratio of the non-aggregated primary particles to the aggregate of the composite particles is more preferably 40% or more, particularly preferably 50% or more, on a number basis.

The higher the ratio of primary particles without aggregation to composite particles is generally, the more preferable, and in particular, there is no upper limit, and it is desirable that the ratio be 100%.

The ratio of the primary particles not aggregated to the composite particles can be measured by a method known in the art, for example, by forming a coating film using a metal pigment composition containing an aggregate of composite particles having metal particles and a metal oxide coating on the surface thereof, obtaining an FE-SEM image (field emission scanning electron microscope image) of a cross section thereof, performing image analysis, or by counting the number of primary particles and aggregated particles in the FE-SEM image by an evaluator. More specifically, the measurement can be performed by the method described in the examples of the present application.

The ratio of the non-aggregated primary particles to the composite particles can be improved, for example, by increasing the amount of the specific solvent, by using the production method of the application 2 and/or the production method of the application 3.

The selection and treatment of the metal particles constituting the composite particles, the kind of oxide metal coating formed on the metal particles, and the production conditions can be appropriately set and controlled. As a conventional technique, there is an attempt to enhance the mechanical dispersion by increasing the stirring rotation speed at the time of the covering treatment and setting the reynolds number to a predetermined value or more, but this method has the following problems: the fine particles treated in the present application are limited in dispersion and the thin particles in the form of scales are broken or deformed by strong stress at the time of stirring.

On the other hand, by performing pretreatment for improving dispersibility on the metal particles before the metal particles are subjected to the covering treatment with the metal oxide, aggregation of the particles at the time of the covering treatment can be suppressed, whereby the ratio of primary particles which are not aggregated can be greatly increased.

For example, when the metal particles as the raw material are dispersed in a solvent and supplied, the solvent is replaced with the same solvent as that used in the coating treatment, and if necessary, the heating treatment is performed for a predetermined period of time to sufficiently compatibilize the solvent with the surfaces of the metal particles, whereby aggregation occurring during the coating treatment can be significantly suppressed. Further, the addition of a small amount of surfactant at this time is also effective for aggregation inhibition.

By these treatments, the dispersibility of the metal particles themselves is improved, and therefore, no need for stirring in a marginal manner is required in the covering treatment, and even mild stirring can produce primary particles free from aggregation. Therefore, the deformation of the particles during the coating treatment can be greatly reduced, and excellent design properties, gloss, suppression of the occurrence of particles, stability in the aqueous coating material, and the like in the coating film can be easily achieved.

In addition to the above, as elements that affect the ratio of the primary particles that are not aggregated, there are mentioned particle diameters of the raw material atomized metal powder and the like in the steps of grinding and sieving/filtering the raw material atomized metal powder and the like using a ball mill and the like, the mass per 1 grinding ball when using a ball mill, the rotation speed of the grinding apparatus, the degree of sieving and press filtering, and the pH, concentration, stirring temperature, stirring time, the kind of stirring apparatus, the power/degree of stirring (the kind and diameter of stirring wings, the rotation speed, the presence or absence of external stirring and the like) at the time of hydrolysis of the raw material such as the organosilicon compound in the step of covering the metal oxide layer such as the silicon compound layer (and other covering layer if necessary), and the ratio of the primary particles that are not aggregated can be controlled by appropriately adjusting them.

The ratio of the curved composite particles to the composite particles is 10% or less on a number basis.

In the composite metal pigment composition of the present embodiment, the ratio of the curved composite particles to the total composite particles contained in the composite metal pigment composition is preferably 10% or less. Thus, a coating film formed using the composite metallic pigment composition exhibits excellent design, gloss, suppression of particle generation, and at the same time, further improvement of stability in aqueous paints and the like is facilitated.

The ratio of the bent composite particles is understood as an index related to the degree of deformation or breakage of the composite particles. When the ratio of the bent composite particles is 10% or less, the degree of deformation or breakage of the composite particles is small, and thus the ratio of the untreated surface (surface on which the oxidized metal coating film is not formed) of each composite particle is reduced, whereby the stability in the aqueous paint is improved, and further, by further facilitating formation of uniform and sufficient coverage of each particle, the aggregation of each particle is further reduced, and therefore, a coating film exhibiting excellent designability, gloss, and particle suppression in the coating film surface formed using the composite metal pigment composition can be obtained.

The smaller the ratio of the curved composite particles to the aggregate of composite particles, the better. The ratio is preferably 6% or less, more preferably 3% or less. The lower the ratio of the curved composite particles is, the more preferable, and therefore, particularly, the lower limit thereof does not exist, and desirably 0%.

The ratio of curved composite particles in the composite metal pigment composition can be measured by a method known in the art, for example, by forming a coating film using a metal pigment composition containing an aggregate of composite particles having metal particles and a metal oxide coating on the surface thereof, obtaining an FE-SEM image (field emission scanning electron microscope image) of a cross section thereof, and performing image analysis. More specifically, the number ratio of the straight line distance between the two ends of the cross section of the metal particle in the FE-SEM image to the particle having a ratio of 0.8 times or less the path length between the two ends along the cross section of the metal particle can be determined as a curved particle. More specifically, the measurement can be performed by the method described in the examples of the present application.

The ratio of the curved composite particles to the composite particles can be reduced by, for example, increasing the amount of the specific solvent, using the production method according to application 2 and/or application 3, or the like.

In the step of covering the metal oxide (and other covering layers as needed), pretreatment for improving dispersibility of the raw material aluminum paste, stirring time, the type of stirring device, stirring power/degree (the type and diameter of stirring blade, rotation speed, presence or absence of external stirring, and the like) and the like may be appropriately adjusted.

Further, since the dispersibility of the particles themselves at the time of the reaction is improved by the pretreatment of the raw aluminum paste, the stirring for the dispersion is gentle enough, and therefore, the deformation of the particles due to the stirring can be greatly reduced.

2 nd cover layer

The coating layer of the composite particles contained in the composite metallic pigment composition of the application 1 is not particularly limited except for having at least 1 layer of the oxidized metal coating layer, and a coating layer other than the oxidized metal coating layer (hereinafter referred to as "2 nd coating layer") may be formed as required.

The 2 nd coating layer preferably contains at least one of a metal (alkali metal; alkaline earth metal; metal such as manganese, iron, cobalt, nickel, copper, silver, etc.), a metal oxide (titanium oxide, zirconium oxide, oxide of iron, etc.), 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.), for example. As the 2 nd coating layer, for example, a molybdenum-containing coating film, a phosphoric acid compound coating film, or the like can be formed. By providing the 2 nd coating layer, the formation of an oxidized metal coating such as a silicon compound-containing layer can be promoted while improving the corrosion resistance of the metal particles.

The 2 nd coating layer (in the case of formation) is particularly preferably formed between the metal particles and the oxide metal coating such as the silicon compound-containing layer. Thus, for example, a layer structure of "metal particles/2 nd cover layer/oxidized metal cover" can be suitably employed. Examples of the molybdenum-containing coating film include, but are not particularly limited to, those disclosed in Japanese patent application laid-open No. 2003-147226, WO 2004/096921, japanese patent application laid-open No. 5979788, and Japanese patent application laid-open No. 2019-151678. As an example of the phosphate compound coating film, a phosphate compound coating film disclosed in japanese patent No. 4633239 is given. As a preferable example of the molybdenum-containing substance constituting the molybdenum-containing coating film, there is mentioned a mixed coordination type heteropolyanion compound disclosed in Japanese patent application laid-open No. 2019-151678.

In another modification, the 2 nd coating layer may be formed outside the metal oxide coating such as the metal particles and the silicon compound-containing layer. In still another modification, the constituent components (molybdenum-containing compound, phosphoric acid compound, etc.) of the 2 nd coating layer may be contained in an oxide metal coating such as a silicon-containing compound layer together with a silicon compound or the like.

The mixed coordination type heteropolyanion compound preferably used for the form of the 2 nd coating layer (typical example, molybdenum-containing coating film) other than the metal oxide coating layer of the composite particles contained in the composite metal pigment composition of the 1 st application is not particularly limited, and specifically, the following examples are given.

The mixed coordination type heteropolyanion of the mixed coordination type heteropolyanion compound that can be used has a structure in which a plurality of polyatoms of the heteropolyanion formed of one element are replaced with other elements, and exhibits physical properties different from those of the mixture of the heteropolyanions.

In the case of the description of the chemical formula, the mixed coordination type heteropolyanion is represented as [ X ] _p M _q N _r O _s ] ^t The heteropolyanion becomes [ X ] _p M _q O _s ] ^t Further, it also interacts with hetero polyanion [ M ] _q O _s ] ^t The distinction is made. Among them, X as a hetero atom represents an element of IIIB, IVB, VB group such as B, si, ge, P, as, and among them, B, si and P are preferable. The polyatomic M, N is preferably Ti, zr, V, nb, mo, W, and represents a transition metal such as Ti, zr, V, nb, ta, mo, W.

Further, p, q, r, s represents the number of atoms, and t represents the oxidation number.

The heteropoly anion compound can have a further large number of structures due to its numerous structures, but as a representative and preferred mixed coordination type heteropoly anion compound, the following mixed coordination type heteropoly acid can be exemplified: h ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstic acid n-hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadic acid n-hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ O (silicotungstic acid n-hydrate), H _4+x SiV _x Mo _12-x O ₄₀ ·nH ₂ O (silico-vanadic acid n-hydrate), and the like. (wherein, x is more than or equal to 1 and less than or equal to 11, and n is more than or equal to 0)

Among these heteropoly anionic compounds, preferred specific examples thereof 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、H ₄ PV ₁ Mo ₁₁ O ₄₀ ·nH ₂ O、H ₆ PV ₃ Mo ₉ O ₄₀ ·nH ₂ O、H ₄ SiW ₃ Mo ₉ O ₄₀ ·nH ₂ O、H ₄ SiW ₆ Mo ₆ O ₄₀ ·nH ₂ O、H ₄ SiW ₉ Mo ₃ O ₄₀ ·nH ₂ O、H ₅ SiV ₁ Mo ₁₁ O ₄₀ ·nH ₂ O、H ₇ SiV ₃ Mo ₉ O ₄₀ ·nH ₂ O, and the like. (wherein n.gtoreq.0)

The mixed coordination type heteropoly anion compound may be used as an acid (so-called mixed coordination type heteropoly acid), or may be used as a (partial or complete) salt using a specific cation as a counter ion.

The counter cation source in the case of using a mixed coordination type heteropolyanion compound as a salt of a specific cation as a counter ion includes, for example, alkali metals selected from lithium, sodium, potassium, rubidium, cesium, and the like; alkaline earth metals such as magnesium, calcium, strontium, and barium; metals such as manganese, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead, and aluminum; inorganic components such as ammonia; and at least one of an amine compound or the like as an organic component. Among the inorganic components, salts of alkali metals, alkaline earth metals, and ammonia are preferable.

Further, in the case where at least one selected from these alkali metal, alkaline earth metal and ammonia is used as a counter cation source, it is more preferable that the counter cation source is selected from H ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstic acid n-hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadic acid n-hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ O (silicotungstic acid n-hydrate), H _4+x SiV _x Mo _12-x O ₄₀ ·nH ₂ The salt of at least one of O (silico-vanadic acid n-hydrate) is used.

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

(R ⁸ -N(-R ¹⁰ )-) _n -R ⁹ (5)

(wherein R is ⁸ 、R ⁹ R is R ¹⁰ May be the same or different, and may be a hydrogen atom, or a hydrocarbon group of 1 to 30 carbon atoms optionally containing an ether bond, an ester bond, a hydroxyl group, a carbonyl group, a mercapto group, or a 1-or 2-valent hydrocarbon group, and R may be optionally ⁸ And R is ⁹ Together forming a 5-or 6-membered cycloalkyl group, or forming a 5-or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a crosslinking group, or R may be arbitrarily selected ⁸ 、R ⁹ And R is ¹⁰ Together form a multiple ring which may contain 1 or more additional nitrogen atoms and/or oxygen atoms as crosslinking groups. R is R ⁸ 、R ⁹ And R is ¹⁰ Hydrogen atoms are not formed at the same time. n represents an integer of 1 to 2. )

Examples of the amine compound as a counter cation source of the mixed coordination type heteropolyanion compound include primary amine, secondary amine, tertiary amine having a mixed hydrocarbon group, alicyclic primary amine, primary amine having an aromatic ring substituent, alicyclic secondary amine, secondary amine having an aromatic ring substituent, asymmetric secondary amine, alicyclic tertiary amine, tertiary amine having an aromatic ring substituent, amine having an ether bond, alkanolamine, diamine, cyclic amine, aromatic amine, and the like, and any mixture thereof.

Among these amine compounds, preferred specific examples include at least one selected from primary, secondary, tertiary, and alkanolamines of linear or branched alkyl groups having 4 to 20 carbon atoms, and examples thereof include butylamine, hexylamine, cyclohexylamine, octylamine, tridecylamine, stearylamine, dihexylamine, di-2-ethylhexylamine, linear or branched ditridecylamine, distearylamine, tributylamine, trioctylamine, linear or branched tridecylamine, tristearylamine, N-dimethylethanolamine, N-methyldiethanolamine, triethanolamine, morpholine, and the like.

More preferably at least one selected from the amine compounds represented by the general formula (5)And is selected from H ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstic acid n-hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadic acid n-hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ O (silicotungstic acid n-hydrate), H _4+x SiV _x Mo _12-x O ₄₀ ·nH ₂ The salt of at least one of O (silico-vanadic acid n-hydrate) is used.

Among the above mixed coordination type heteropoly anion compounds, H is most preferred ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstic acid n-hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadic acid n-hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ Mixed coordination type heteropoly acid of O (silicotungstic molybdic acid n hydrate) or organic amine salt of these mixed coordination type heteropoly acid.

The 2 nd coating layer other than the metal oxide coating layer of the composite particles contained in the composite metal pigment composition of the present embodiment may be a layer containing another corrosion inhibitor in order to further improve the corrosion resistance of the metal particles (preferably aluminum particles or aluminum alloy particles) serving as nuclei. The corrosion inhibitor to be added is not particularly limited, and any known corrosion inhibitor may be used. The amount thereof may be within a range that does not hinder the desired effect of the application 1. Examples of such corrosion inhibitors include acid phosphate esters, dimer acids, organic phosphorus compounds, and metal salts of molybdic acid.

The metal oxide coating layer and/or the 2 nd coating layer of the composite particles contained in the composite metal pigment composition may further contain an organic oligomer or polymer as another layer from the viewpoints of adhesion and chemical resistance at the time of forming a coating film.

The metal oxide coating layer and/or the 2 nd coating layer of the composite particles may contain at least one member selected from the group consisting of inorganic phosphoric acids and salts thereof, and acidic organic (phosphorous) acid esters and salts thereof, from the viewpoint of storage stability, or may be contained as another layer.

These compounds are not particularly limited, and for example, those disclosed in Japanese patent application laid-open No. 2019-151678 can be used.

Composite metallic pigment composition

The composite metallic pigment composition of the application 1 comprises: the composite particles containing metal particles and 1 or more layers of metal oxide coating on the surface thereof satisfy the conditions (1) to (3), and the composite metal pigment composition satisfies the conditions (4) to (6) and does not satisfy the other conditions, but may contain, as a residual part of solid components (nonvolatile components) other than the composite particles, an unreacted organosilicon compound, a compound forming the 2 nd coating layer, an oligomer or a polymer derived from them, and the like, and may contain a solvent such as water used in the production process other than a specific amount of a specific solvent associated with the condition (5).

The composite metal pigment composition may contain a silicon compound which is a hydrolysate of an organosilicon compound (for example, at least one of the organosilicon compounds represented by the above general formula (1), and at least one selected from the silane coupling agents represented by any one of the above general formulae (2), (3) and (4), and partial condensates thereof) and/or a condensate thereof.

In the composite metal pigment composition, there may be a compound forming the optional 2 nd coating layer (molybdenum-containing compound, for example, mixed coordination type heteropolyanion compound, for optional mode of forming a molybdenum-containing coating film as the 2 nd coating layer).

In the composite metallic pigment composition, an organic oligomer or polymer can be arbitrarily selected.

At least one selected from the group consisting of inorganic phosphoric acids and salts thereof, and acid organic (phosphorous) phosphates and salts thereof, which are arbitrarily selected, may be present in the composite metal pigment composition.

In the composite metallic pigment composition, a solvent containing water/hydrophilic solvent used in the production process can be present.

The composite metallic pigment composition may contain any component other than the above-mentioned components, which are arbitrarily selected. Examples of the optional component include at least one of an antioxidant, a light stabilizer, and a surfactant.

As the antioxidant, antioxidants typified by phenol compounds, phosphorus compounds, and sulfur compounds can be used.

As the light stabilizer, a light stabilizer used as the antioxidant described above may be used, and light stabilizers typified by benzotriazole-based compounds, benzophenone-based compounds, salicylate-based compounds, cyanoacrylate-based compounds, oxalic acid derivatives, hindered amine-based compounds (HALS), and hindered phenol-based compounds may be used.

Examples of the surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether and polyoxyethylene oleyl ether, polyoxyalkylene alkylphenyl ethers such as polyoxyethylene nonylphenyl ether, polyoxyalkylene alkylamino ethers such as polyoxyethylene lauryl amino ether and polyoxyethylene stearyl amino ether, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate and sorbitan monooleate, and sorbitan fatty acid esters such as sorbitan monolaurate; polyoxyalkylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate and other polyoxyalkylene sorbitan fatty acid esters; polyalkylene glycol fatty acid esters such as polyethylene glycol monolaurate, polyethylene glycol monooleate, polyethylene glycol monostearate, polyethylene glycol dilaurate and polyethylene glycol distearate; nonionic surfactants represented by glycerol fatty acid esters such as lauric acid monoglyceride, stearic acid monoglyceride and oleic acid monoglyceride include sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene octyl phenyl ether sulfate, sodium polyoxyethylene nonylphenyl ether sulfate, triethanolamine lauryl sulfate, sodium lauryl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate and other sulfate salts; sulfonates such as sodium dodecylbenzenesulfonate, sodium alkylnaphthalene sulfonate, and sodium dialkylsulfosuccinate; examples of the anionic surfactant represented by phosphate salts such as potassium alkyl phosphate include cationic surfactants represented by quaternary ammonium salts such as lauryl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride and stearyl trimethyl ammonium chloride, and 1 or 2 or more selected from these surfactants can be used. Among them, as particularly preferable examples, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, or a mixture thereof can be exemplified.

Method for producing composite metallic pigment composition

The method for producing the composite metallic pigment composition according to the application 1 is not particularly limited, but is particularly preferably produced by the method for producing the composite metallic pigment composition according to the application 2 and/or the method for producing the composite metallic pigment composition according to the application 3. The production method of the application 2 and the production method of the application 3 can produce a composite metal pigment composition having a high nonvolatile content (solid content) while effectively preventing aggregation and suppression of composite particles, and are therefore particularly suitable for production of the composite metal pigment composition of the application 1.

The object to which the production method according to application 2 and the production method according to application 3 are applied is not limited to the production of the composite metallic pigment composition according to application 1, but is suitably used for the production of various composite metallic pigment compositions.

The production method according to the application 2 is a method for producing a composite metallic pigment composition having the following steps 1) to 3),

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal,

The solvent is a mixed solvent of 2 or more solvents which are compatible with each other and have a boiling point difference of 10 ℃ or more,

The production method according to the application 3 is a method for producing a composite metallic pigment composition having the following steps 1) to 3),

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal,

the solvent volatile in step 3) is performed in 3 stages or more.

That is, the production method according to the application 2 and the production method according to the application 3 each include:

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal, and

3) Washing, filtering and volatilizing the composite particles having the metal particles and the oxidized metal coating formed on the surface thereof obtained in the step 2).

In the application 2, the solvent is a mixed solvent of 2 or more solvents having compatibility and a boiling point difference of 10 ℃ or more, and the solvent in the step 3) is volatilized in a state of a slurry containing the composite particles and the solvent, but the application 3 is not limited thereto, and the application 2 is different from the application 3 in this respect, and the application 3 is carried out in 3 stages or more, whereas the application 2 is not limited thereto, and the application 2 is different from the application 3 in this respect.

These steps are described below.

1) A step of dispersing the metal particles in a solvent

In step 1), metal particles are dispersed in a solvent. By dispersing the metal particles in the solvent, aggregation of the particles can be suppressed in the next step of 2) covering the metal particles with the metal oxide, and as a result, the obtained composite particles are also excellent in dispersibility, and the ratio of the primary particles that are not aggregated can be greatly increased.

The method of dispersing the metal particles in the solvent is not particularly limited, and a method of adding the metal particles to the solvent, and then applying stirring, irradiating with ultrasonic waves, or the like is preferably employed.

In addition, pretreatment is also preferable in order to improve dispersibility of the metal particles.

The stirring can be performed by a known or commercially available stirring device. For example, at least one of a kneader, a mixer, a rotary vessel mixer, a stirred tank reactor, a V-type mixer, a double cone mixer, a screw mixer, a sigma mixer, a flash mixer, an air flow mixer, a ball mill, an edge mill, and the like can be used.

Among these agitators, an apparatus for agitating by stirring blades (impellers) is preferably used. The stirring blade plays a cyclic role of flowing the entire system including the metal particles and the solvent, and plays a pressure shearing role, so that aggregation of the metal particles can be suppressed and the metal particles can be dispersed more effectively.

The shape of the stirring vane is not particularly limited, and for example, an anchor shape, a propeller shape, a turbine shape, a fan turbine shape, a blade shape, an inclined blade shape, or a gate shape may be used. The stirring vanes of these shapes may be combined in a plurality of stages.

The stirring speed is preferably such that the stirring wings are not exposed by a vortex (vortex) generated by stirring. In order to suppress the vortex generated by stirring, a cylindrical tank, a square tank, a tank provided with a baffle, or the like may be suitably used.

The linear velocity of stirring (tip velocity of stirring blade) is preferably 0.5 to 30m/s, more preferably 1 to 20m/s. The stirring linear velocity is in the range of 0.5 to 30m/s, whereby the dispersibility of the metal particles can be improved, and further, a composite metal pigment composition having less aggregation of the particles, excellent design properties, gloss, coating appearance and less gas generation can be more easily obtained. In addition, when the linear velocity of stirring is within the above range, breakage of metal particles (for example, scaly aluminum powder) is prevented and aggregation of the particles can be effectively suppressed.

The ultrasonic treatment is not particularly limited, and may be performed at a speed of usually 10 to 1000W, preferably 50 to 800W, and usually 20 seconds to 10 minutes, preferably 30 seconds to 5 minutes.

For example, in the case where metal particles as a raw material are dispersed in an inert solvent and supplied as a pretreatment, the solvent may be replaced with the same solvent as that used in the covering treatment. Further, by performing the heating treatment for a predetermined period of time as needed to sufficiently compatibilize the solvent with the surfaces of the metal particles, aggregation occurring in the step of 2) covering the metal particles with the oxidized metal can be greatly suppressed. The heat treatment temperature is preferably about 30 to 60 ℃, and the treatment time is preferably optimized during 3 hours to 7 days. In the step of performing the covering treatment, a hydrophilic solvent such as ethanol, isopropanol, methoxypropanol or the like is preferably used, and therefore, the same hydrophilic solvent as that used in the reaction is preferably used in the pretreatment.

Furthermore, the addition of a small amount of surfactant at this time is also effective for aggregation inhibition by pretreatment. The surfactant is not particularly limited, but nonionic surfactants and anionic surfactants are preferable, and nonionic surfactants are particularly preferable.

1) The step of dispersing the metal particles in the solvent may be carried out at a temperature of usually about 10 to 80 ℃, preferably about 15 to 70 ℃, and most preferably about room temperature (about 20 to 60 ℃). The step of 1) dispersing the metal particles in the solvent (this treatment is also included in the case of performing ultrasonic treatment) may be performed within a period of 5 minutes to 20 hours, preferably within a period of 10 minutes to 5 hours.

2) Process for coating metal particles with oxidized metal

The metal oxide coating can be formed on the metal particles by performing the step of 2) coating the metal particles with the metal oxide after the step of 1) dispersing the metal particles in the solvent.

Since silicon oxide is preferably used for the metal oxide coating as described above, the following description will be given of a specific example of the step 2) by taking as an example an embodiment in which at least 1 layer of the metal oxide coating is a silicon-containing compound layer.

Process for forming silicon-containing compound layer

In the forming step, the silicon-containing compound layer is formed by, for example, reacting a mixed solution containing metal particles, a silicon-containing raw material containing at least one of the organic silicon compounds, a solvent, and, if necessary, other optional components.

In step 1), the metal particles are dispersed in a solvent, and therefore, a silicon-containing raw material is usually added thereto in step 2).

As the metal particles, the above-mentioned metal particles may be used, but particles of aluminum or aluminum alloy may be particularly suitably used. In addition, as described above, the metal particles having a scaly shape are preferably used for the particle shape. As the metal particles, known or commercially available metal particles (typically, paste-like aluminum flakes) can be used.

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

As the silicon-containing raw material, an organosilicon compound can be used. The organosilicon compound is not limited, but the aforementioned organosilicon compound can be preferably used.

At least one of the organosilicon compound represented by the above formula (1) (typically, tetraalkoxysilane) and/or a condensate thereof, and the silane coupling agent represented by any one of the above formulas (2) to (4) can be suitably used.

Hereinafter, a case where tetraalkoxysilane is used as the organosilicon compound represented by the above formula (1) will be described as an example. In the following, the tetraalkoxysilane and/or the condensate thereof may be referred to simply as "tetraalkoxysilane".

When the tetraalkoxysilane represented by the above formula (1) and the silane coupling agent represented by any one of the above formulas (2) to (4) are used in combination, a method (referred to as "method 1") in which both are used in combination can be employed. Alternatively, a method including a step of forming the 1 st silicon-containing compound layer by treating the metal particles with one of them and forming the 2 nd silicon-containing compound layer by treating the metal particles with the other of them (referred to as "method 2") may be employed.

As the 1 st method, for example, there are: a step of forming a silicon-containing compound layer by appropriately adjusting the pH of a mixture containing metal particles, the tetraalkoxysilane represented by the formula (1) and the silane coupling agent represented by any one of the formulas (2) to (4), and subjecting the tetraalkoxysilane and the silane coupling agent to hydrolysis/condensation reaction.

As the 2 nd method, for example, there may be mentioned: a step of forming a 1 st silicon-containing compound layer (e.g., a silica coating film formed of amorphous silica) on the surface of the metal particles by appropriately adjusting the pH of a mixed solution containing the metal particles and the tetraalkoxysilane represented by the formula (1) and subjecting the tetraalkoxysilane to hydrolysis/condensation reaction; and a step of forming a 2 nd silicon-containing compound layer on the surface of the 1 st silicon-containing compound layer by adjusting the pH of a mixed solution containing metal particles and a silane coupling agent represented by any one of the above formulas (2) to (4) and subjecting the silane coupling agent to hydrolysis/condensation reaction.

The amount of the tetraalkoxysilane represented by the above formula (1) or the condensate thereof can be appropriately set depending on the kind of the tetraalkoxysilane used and the like. For example, from the viewpoint of the effect of the covering treatment and from the viewpoint of suppressing aggregation of metal particles or reduction of the brightness, the amount thereof may be 2 to 200 parts by mass, more preferably 5 to 100 parts by mass, relative to 100 parts by mass of the metal particles (solid content).

The amount of the silane coupling agent represented by any one of the above formulas (2) to (4) is not particularly limited, and may be generally about 0.1 to 20 parts by mass, particularly preferably 1 to 5 parts by mass, per 100 parts by mass of the metal particles (solid content). The amount of the coating composition is about 0.1 to 20 parts by mass, whereby a desired effect of coating treatment and preferable coating properties can be obtained.

The solvent in the mixed solution, that is, the solvent used for the hydrolysis reaction and/or condensation reaction of the organosilicon compound may be appropriately selected depending on the kind of the silicon-containing raw material used, and water, a hydrophilic organic solvent, or a mixed solvent thereof may be generally used. By using these solvents, the uniformity of the reaction, the uniformity of the resulting hydrolysates and/or condensation reactants can be improved. In the method of directly forming the silicon-containing compound layer on the metal particles, it is particularly preferable that the solvent of the mixed solution 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.

The hydrophilic organic solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, propanol, butanol, isopropanol, and octanol; ether alcohols such as 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 esters thereof; glycols of ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, polyoxyethylene glycol, polyoxypropylene glycol, ethylene propylene glycol; ethyl cellosolve, butyl cellosolve, acetone, methoxypropanol, ethoxypropanol, other alkoxy alcohols, and the like. They may be used in an amount of 1 or 2 or more.

The amount of the solvent used in the step of forming the silicon-containing compound layer (in the case of performing the preliminary dispersion of the metal particles, the amount of the solvent used is not limited, and may be generally about 100 to 10000 parts by mass, and particularly preferably 200 to 2000 parts by mass, relative to 100 parts by mass of the metal particles (solid content). The use amount of the solvent is 100 parts by mass or more, whereby the increase in viscosity of the mixed solution (slurry) is suppressed, and appropriate stirring can be performed. In addition, the use amount of the solvent is 10000 parts by mass or less, whereby the recovery and regeneration costs of the treatment solution can be prevented from increasing. In the case of the method 2, the amount of the solvent used herein refers to the total amount of the solvent used for the formation of the 1 st silicon-containing compound layer and the formation of the 2 nd silicon-containing compound layer.

Other additives may be blended as necessary in the above-mentioned mixed solution within a range that does not inhibit the effect of the application 1. Examples of the catalyst include a catalyst such as a hydrolysis catalyst and a dehydration condensation catalyst, a surfactant, a metal corrosion inhibitor, and the like.

Among them, a hydrolysis catalyst can be suitably used. By blending the hydrolysis catalyst, the pH of the mixed solution is adjusted, and the organic silicon compound can be efficiently hydrolyzed and dehydrated and condensed, and as a result, a silicon compound-containing layer can be efficiently and reliably formed on the surface of the metal particles.

The hydrolysis catalyst is not particularly limited as long as it is a known or commercially available hydrolysis catalyst. As the hydrolysis catalyst, for example, inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and the like can be used; organic acids such as benzoic acid, acetic acid, chloroacetic acid, salicylic acid, oxalic acid, picric acid, phthalic acid, and malonic acid; phosphonic acids such as vinylphosphonic acid, 2-carboxyethane phosphonic acid, 2-aminoethane phosphonic acid, and octane phosphonic acid. These hydrolysis catalysts may be used singly or in combination of 2 or more.

As the hydrolysis catalyst, for example, inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide can be used; inorganic alkali salts such as ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, etc.; amines such as monomethyl amine, dimethyl amine, trimethyl amine, monoethyl amine, diethyl amine, triethyl amine, monoethanolamine, diethanolamine, triethanolamine, N-dimethylethanolamine, ethylenediamine, pyridine, aniline, choline, tetramethyl ammonium hydroxide, guanidine, and the like; salts of organic acids such as ammonium formate, ammonium acetate, monomethyl amine formate, dimethyl amine acetate, pyridine lactate, guanidinoacetic acid, and aniline acetate. These hydrolysis catalysts may be used in an amount of 1 or 2 or more.

The amount of the hydrolysis catalyst to be added is not particularly limited, but is usually 0.01 to 20 parts by mass, and particularly preferably 0.02 to 10 parts by mass, per 100 parts by mass of the metal particles (solid content). When the amount of the additive is 0.01 part by mass or more, the deposition amount of the silicon-containing compound layer can be made sufficient. In addition, by the addition amount of 20 parts by mass or less, aggregation of the metal particles can be effectively suppressed.

The composite metal pigment composition according to the application 1 is preferably produced by stirring the mixture with a proper strength.

The temperature of the mixed solution may be either normal temperature or under heating. The temperature of the mixed solution is usually 20 to 90℃and is particularly preferably controlled within a range of 30 to 80 ℃. The treatment time can be shortened by increasing the formation rate of the silicon-containing compound layer at 20 ℃ or higher. On the other hand, when the temperature is 90℃or lower, the reaction can be easily controlled, and the probability of obtaining desired composite particles can be improved.

The stirrer for stirring the mixed solution is not particularly limited, and a known stirrer that can effectively and uniformly stir the mixed solution containing aluminum particles and the organosilicon compound can be used. Specific examples thereof include kneaders, rotary vessel mixers, stirred tanks, V-type mixers, double cone mixers, screw mixers, sigma mixers, flash mixers, air mixers, ball mills, and wheel mills.

The temperature of the mixed solution when the mixed solution containing the metal particles and the organosilicon compound is stirred is usually about 10 to 100 ℃, and particularly preferably 30 to 80 ℃. By setting the temperature to 10 ℃ or higher, the reaction time for obtaining a sufficient treatment effect can be shortened. In addition, by setting the temperature to 100 ℃ or lower, the reaction for obtaining the desired composite metal pigment composition can be more easily controlled.

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

In the above mixed solution, the silicon-containing raw material is subjected to hydrolysis/condensation reaction to form a silicon-containing compound layer on the surface of the metal particles (or via the 2 nd coating layer). The hydrolysis/condensation reaction can be carried out, in particular, by adjusting the pH of the mixed solution.

In the step of adjusting the pH, particularly in the step of forming the silicon-containing compound layer on the surface of the metal particles (or via the 2 nd coating layer), the pH of the mixed solution is preferably adjusted appropriately so that the pH can be maintained within a constant range. In this case, the pH is preferably adjusted by adding a hydrolysis catalyst, but other acidic or basic compounds may be used to adjust the pH as long as the properties of the composite metal pigment composition of the application 1 are not impaired.

When an alkaline hydrolysis catalyst is used as the hydrolysis catalyst, the pH is preferably 7 to 13. By having a pH of 7 or more, the silicon-containing compound layer can be formed rapidly. On the other hand, when the pH is 13 or less, aggregation of metal particles and a decrease in brightness can be suppressed, and further, generation of hydrogen gas due to corrosion can be prevented.

When an acidic hydrolysis catalyst is used as the hydrolysis catalyst, the pH is preferably 1.5 to 7, particularly preferably 2 to 6. By properly controlling the reaction at a pH of 1.5 or more, a composite metal pigment composition containing desired composite particles can be easily obtained. On the other hand, when the pH is 7 or less, the precipitation rate of the silicon-containing compound layer can be kept high.

In the case of using either of the above methods 1 and 2, the hydrolysate of the organic silicon compound represented by the above general formula (1) and/or the condensate thereof is preferably added in an amount of 0.01 to 50 parts by mass, more preferably 1 to 30 parts by mass, in terms of the state of completion of the hydrolysis and condensation reaction, relative to 100 parts by mass of the metal particles (solid content). Further, the hydrolysate and/or condensate derived from the silane coupling agent represented by any one of the above general formulae (2) to (4) and/or a partial condensate thereof is added in an amount of 0.01 to 10 parts by mass, more preferably 0.05 to 2 parts by mass in terms of the state of completion of the hydrolysis and condensation reaction, per 100 parts by mass of the metal particles (solid component).

The amount of the hydrolysate and/or condensate of the organosilicon compound represented by the general formula (1) to be added can be calculated by multiplying the mass of the organosilicon compound represented by the general formula (1) used in producing the composite metal pigment composition by the mass ratio of the organosilicon compound before and after the reaction when the organosilicon compound is completely subjected to hydrolysis and condensation reaction.

For example, when Tetraethoxysilane (TEOS) is used as the organosilicon compound represented by the general formula (1), the addition amount of the hydrolysate of the organosilicon compound and/or the condensate thereof can be calculated using the following mass ratio before and after the hydrolysis and condensation reaction.

(hydrolysis)

Si(OC ₂ H ₅ ) ₄ (molecular weight: 208) +4H ₂ O→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: 60X 2) +4H ₂ O

Since the mass of the above is 60/208=0.288 times before and after the hydrolysis and condensation reaction, for example, when TEOS 10 parts by mass is used per 100 parts by mass of the metal particles (solid content), the amount of the hydrolysate and/or condensate thereof added is 0.288 times, that is, 2.88 parts by mass.

Similarly, the amount of the hydrolysate and/or condensate of the silane coupling agent represented by any one of the general formulae (2) to (4) to be added may be calculated by multiplying the mass of the silane coupling agent represented by any one of the general formulae (2) to (4) and/or partial condensate thereof used in producing the composite metal pigment composition by the mass ratio before and after the reaction when the silane coupling agent and/or partial condensate thereof is completely hydrolyzed and condensed.

For example, when methyltrimethoxysilane is used as the silane coupling agent represented by the general formula (2), the following mass ratio before and after the hydrolysis and condensation reaction can be used to calculate the addition amount of the hydrolysate of the silane coupling agent and/or the condensate thereof.

(hydrolysis)

CH ₃ Si(OCH ₃ ) ₃ (molecular weight: 136) +3H ₂ O→CH ₃ Si(OH) ₃ (molecular weight: 94) + (CH) ₃ OH) ₃

(condensation)

CH ₃ Si(OH) ₃ (molecular weight: 94) +CH ₃ Si(OH) ₃ (molecular weight: 94) → (SiCH) ₃ O _1.5 ) ₂ (molecular weight: 67X 2) +3H ₂ O

Since the mass of the above is 67/136=0.49 times before and after the hydrolysis/condensation reaction, for example, when 1.23 parts by mass of methyltrimethoxysilane is used per 100 parts by mass of the metal particles (solid content), the amount of the hydrolysate and/or condensate thereof to be added is 0.49 times, that is, 0.60 parts by mass.

3) Washing, filtering and volatilizing solvent for composite particles

2) After the step of covering the metal particles with the metal oxide is completed, in order to recover the obtained composite particles to obtain a desired composite metal pigment composition, 3) the step of washing, filtering, and volatilizing the solvent may be performed on the composite particles.

In the production of the composite metallic pigment composition of the application 1, the step 3) is not necessarily carried out, but is preferably carried out.

In the method for producing a composite metallic pigment composition according to the application 2, step 3) is carried out, wherein the solvent is a mixed solvent of 2 or more solvents which are compatible with each other and have a boiling point of 10 ℃ or more, and the solvent in step 3) is volatilized in a state of a slurry containing the composite particles and the solvent.

In the method for producing a composite metallic pigment composition according to the application 3, the step 3) is performed, and the solvent volatile in the step 3) is performed in 3 stages or more.

The washing in step 3) may be performed by a method commonly used in the art, for example, washing the slurry or cake containing composite particles obtained in step 2) with an organic solvent. By washing, water, unreacted substances, an undesirable solvent in the final composite metal pigment composition, and the like can be removed from the slurry, cake, and the like containing the composite particles.

In the washing, stirring is preferably performed, and the stirring conditions are not particularly limited, and for example, the same conditions as those described above in connection with step 1) can be employed.

The temperature, time, etc. during the washing in the step 3) are not particularly limited, and the washing may be carried out at a temperature of usually 10 to 70 ℃, preferably 15 to 60 ℃ for 5 to 180 minutes, preferably 10 to 120 minutes.

In the washing, an organic solvent is preferably used, and from the viewpoints of removal of moisture, convenience in using the composite metal pigment composition for an aqueous paint, and the like, a hydrophilic organic solvent is more preferably used. The hydrophilic organic solvent is particularly preferably one having a boiling point of 80 to 150℃and washing with such an organic solvent makes it easier to satisfy the condition that the solvent (5) in the application 1 has a hydrophilic property and a boiling point of 80 to 150℃accounts for 80% by mass or more of the non-solid content of the composite metal pigment composition. Preferable examples of the solvent having a hydrophilic property and a boiling point of 80 to 150℃include methoxypropanol, isopropanol, isobutanol, n-butanol, n-propanol and the like.

The number of times of washing is not particularly limited, and washing may be performed only 1 time, or may be performed a plurality of times, for example, 2 to 5 times. In the case of performing washing a plurality of times, washing and filtration may be alternately performed. In addition, it is also one of preferable examples to perform washing by continuously or intermittently flowing a washing liquid using a suction filter.

The filtration in step 3) may be carried out by a method commonly used in the art. For example, a gas permeability of a general type can be used10-100 ml/cm ² Preferably, the air permeability is 20 to 80 ml/cm per minute ² The filtration is carried out by suction filtration or pressure filtration using a filter such as a polypropylene filter cloth, a metal filter, a glass filter, or a ceramic filter having an equivalent pore size, and a filter press, a belt press, or a centrifugal filter is suitably used. By filtering, water, unreacted materials, and solvents which are not preferable in the final composite metallic pigment composition can be removed from the composite particles obtained in the step 2).

The temperature and pressure of the filtration in the step 3) are not particularly limited, and in the case of using a suction filter type filter, the filtration may be carried out under conditions of a temperature of 10 to 70 ℃, preferably 15 to 60 ℃, and a pressure of 0.11 to 0.9MPa, preferably 0.15 to 0.5 MPa.

The solid content of the slurry, cake, or the like containing the 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.

The amount of solid components such as slurry containing composite particles and cake after filtration is preferably high from the viewpoint of low VOC, and for this reason, the pressure at the time of filtration may be set high, but the high pressure at the time of filtration may cause aggregation and deformation of composite particles, and therefore the pressure is preferably set in consideration of this as well.

The solid-liquid separation technique other than filtration such as filtration, centrifugal separation, decantation and the like may be appropriately combined.

The number of times of filtration is not particularly limited, and filtration may be performed only 1 time, or washing and filtration may be performed alternately a plurality of times. The conditions that the solvent (5) in the application 1 is hydrophilic and has a boiling point of 80 to 150 ℃ and the solvent accounts for 80 mass% or more of the non-solid content of the composite metal pigment composition are further easily satisfied by alternately washing and filtering a plurality of times, thereby further effectively removing water, unreacted substances, and solvents which are not preferable in the final composite metal pigment composition.

In the filtration, the solvent is preferably volatilized by the gas at the same time as the slurry, the surface of the cake, and the void. As a result, a composite metal pigment composition having a high solid content in which a low-boiling solvent is preferentially volatilized and a high-boiling solvent component mainly remains is easily obtained.

The solvent evaporation in step 3) can be carried out by a method commonly used in the art. The solvent evaporation may be performed, for example, by heating, depressurizing, venting, combinations thereof, and the like.

Since the volatile component is removed by the solvent evaporation, and the ratio of the solid component is improved, the composite metallic pigment composition satisfying the condition that the solid component concentration of the composite metallic pigment composition (4) in the application 1 is 70 to 95 mass% can be effectively produced. Further, since the solvent is volatilized, the solvent and the like which are not preferable in the composite metal pigment composition can be removed, and therefore, the composite metal pigment composition satisfying the condition that (5) the solvent having hydrophilicity and a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid component of the composite metal pigment composition can be further easily produced.

The temperature, pressure, time and the like of the solvent volatilization in the step 3) are not particularly limited, and the solvent volatilization degree can be usually confirmed under the conditions that the temperature is 15 to 100 ℃, preferably 20 to 80 ℃, more preferably 30 to 70 ℃, and the pressure is 0.1 (normal pressure) to 0.001MPa, preferably 0.05 to 0.01MPa in terms of absolute pressure.

When the solvent is volatilized by ventilation, it is preferable to use dry air, and the solvent is suitably regulated while confirming the degree of volatilization of the solvent with respect to the dew point and the flow rate of ventilation.

The composite metallic pigment composition may be obtained directly by solvent evaporation, or may be obtained through a further process. The solid content of the composite metal pigment composition after the solvent is volatilized 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 metallic pigment composition according to the application 2, the solvent in the step 3) is a mixed solvent of 2 or more solvents which are compatible with each other and have a boiling point difference of 10 ℃. The solvent used in the steps before the above is replaced by a mixed solvent obtained by mixing a low boiling point solvent, which is a mixed solvent of 2 or more solvents having compatibility and a boiling point difference of 10 ℃ or more, and the low boiling point solvent is selectively volatilized, whereby a solvent which is desired to be remained, for example, a hydrophilic solvent having a boiling point of 80 to 150 ℃ can be selectively remained. In addition, since the low boiling point solvent is relatively easy to volatilize and extremely reduced pressure such as at a high temperature is not required, the concentration of the solid content can be improved while the deformation and aggregation of the composite particles are relatively easily suppressed.

The difference in boiling points between 2 or more solvents constituting the mixed solvent is preferably 10 to 80 ℃, particularly preferably 20 to 60 ℃.

As the solvent on the high boiling point side, methoxypropanol, isobutanol, n-butanol and the like can be preferably used.

As the solvent on the low boiling point side, isopropyl alcohol, n-propyl alcohol, ethyl alcohol, and the like can be preferably used.

In particular, methoxypropanol as a solvent on the high-boiling point side and isopropanol as a solvent on the low-boiling point side are preferably used in combination.

In the method for producing a composite metallic pigment composition according to claim 2 of the present application, the solvent in step 3) is volatilized in a state of a slurry containing the composite particles and the solvent.

In the step 3), the mixed solvent of 2 or more solvents which are compatible with each other and have a boiling point of 10 ℃ or higher is volatilized in a state of a slurry containing the composite particles and the solvent, so that the solvent on the low boiling point side volatilizes and the solvent on the high boiling point side remains in the composite metal pigment composition more easily.

In the method for producing a composite metallic pigment composition according to the application 3, the solvent volatile in the step 3) is carried out in 3 stages or more. Although the solvent evaporation in 3 or more stages may be performed continuously in this case, it is preferable to perform a step of homogenizing the entire solvent component contained in the slurry, for example, a step of stirring, aging, or the like, between the solvent evaporation in 1 stage and the solvent evaporation in the subsequent stage. In this step of homogenizing the solvent component, the solvent may be newly added and partially replaced.

By performing the volatilization of the solvent in 3 or more stages, and preferably by alternately conducting the volatilization and dispersion, the formation of a part where the solvent is small is suppressed locally, and the aggregation and deformation of the composite particles are effectively prevented, and at the same time, the composite metallic pigment composition having a high solid content and a preferable solvent composition, such as the composite metallic pigment composition of the application 1, can be produced relatively easily and effectively.

In the method for producing a composite metallic pigment composition according to application 2 and 3, a solvent having a low water content is preferably used from the viewpoint of suppressing aggregation of composite particles. In particular, the solvent in step 3) is preferably low in water content when the solvent volatilizes. The water content of the solvent is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 1% by mass or less.

In this case, the moisture content of the entire system of the composite metal pigment composition obtained may be preferably 0.1 mass% or less, more preferably 0.05 mass% or less, and therefore, it becomes easier to reduce the residue content to preferably 0.1 mass% or less, more preferably 0.003 mass% or less of the solid content.

Other steps

Preferably, when the composite metal pigment composition of the application 1 is produced by the method for producing a composite metal pigment composition of the application 2 and/or 3, the method may further include a step of pulverizing metal particles or the like and a step of forming a coating layer other than the oxidized metal coating layer, in addition to the steps 1) to 3).

Crushing, sieving, filtering, etc. of metal particles

The metal particles may be crushed, sieved, and/or filtered prior to the step of 1) dispersing the metal particles in the solvent. The metal particles are crushed, sieved, and/or filtered to have a more uniform and fine particle diameter, and thus are preferable from the viewpoint of production of a composite metal pigment composition containing uniform and fine composite particles.

Here, a case where aluminum powder is used as the metal particles will be exemplified.

The aluminum powder is usually obtained by pulverizing atomized aluminum powder and/or aluminum foil in the presence of a pulverizing aid or an inert solvent by a method commonly used in the pigment industry such as a dry ball mill method, a wet ball mill method, an attritor method, or a triturator method, to form a so-called flake shape, and after this step, subjecting the powder to necessary steps such as sieving (classification), filtration, washing, and mixing.

Examples of the pulverizing aids include fatty acids, fatty amines, fatty amides, and fatty alcohols. Oleic acid, stearic acid, stearyl amine and the like are generally preferred. Examples of the inert solvents include mineral spirits, solvent naphthas, toluene, xylene, and other inert solvents exhibiting hydrophobicity, which may be used alone or in combination. The pulverizing aid and the inactive solvent are not limited to them.

The pulverization step is preferably pulverization by a wet ball mill method from the viewpoint of preventing dust explosion and ensuring safety.

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

Step 2 of Forming the coating layer

The composite particles constituting the composite metal pigment composition of the application 1 preferably have a coating layer (coating layer 2) other than the oxidized metal coating layer, preferably a coating layer containing at least one selected from the group consisting of a metal, a metal oxide, a metal hydrate and a resin, in addition to the oxidized metal coating layer. The 2 nd coating layer (in the case of formation) is particularly preferably formed between the metal particles and the oxide metal coating such as the silicon compound-containing layer. Thus, such a layer structure of "metal particles/2 nd cover layer/oxidized metal cover" can be suitably employed.

The 2 nd coating layer is not particularly limited, and may be a molybdenum-containing coating film, a phosphoric acid compound coating film, or the like. As a preferable example of the molybdenum-containing substance constituting the molybdenum-containing coating film, there is mentioned a mixed coordination type heteropolyanion compound disclosed in Japanese patent application laid-open No. 2019-151678. Examples of the constituent components of the 2 nd coating layer including the mixed coordination type heteropolyanion compound are as described above.

Hereinafter, a description will be given by taking, as an example, a mode in which a molybdenum-containing coating film is formed as a 2 nd coating layer between metal particles and an oxidized metal coating such as a silicon-containing compound layer.

In the case where a molybdenum-containing coating film is formed as the 2 nd coating layer between the metal particles and the oxidized metal coating layer such as the silicon-containing compound layer, the molybdenum-containing coating film can be formed on the surfaces of the metal particles by stirring a mixed solution containing the metal particles and a molybdenum compound (typically, a mixed coordination type heteropolyanion compound) before the oxidized metal coating layer such as the silicon-containing compound layer is formed.

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

The stirrer for stirring the mixed solution containing the metal particles and the molybdenum compound is not particularly limited, and a known stirrer that can effectively and uniformly stir the mixed solution containing the metal particles and the molybdenum compound can be used. Specific examples thereof include kneaders, rotary vessel mixers, stirred tanks, V-type mixers, double cone mixers, screw mixers, sigma mixers, flash mixers, air mixers, ball mills, and wheel mills. Examples of the stirring blade of the stirrer are not particularly limited, and include an anchor blade, a propeller blade, a turbine blade, and the like.

The amount of the molybdenum compound to be used may be appropriately set depending on the kind of the molybdenum compound to be used and the like. The amount is usually 0.02 to 20 parts by mass, and particularly preferably 0.1 to 10 parts by mass, per 100 parts by mass of the metal particles (solid content). The content of 0.02 parts by mass or more can provide a sufficient treatment effect. In addition, the brightness of the obtained composite metallic pigment composition can be kept high by the content of 20 parts by mass or less.

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

Examples of the hydrophilic organic solvent include alcohols such as methanol, ethanol, propanol, butanol, isopropanol, and octanol; ether alcohols such as 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 esters thereof; glycols of ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, polyoxyethylene glycol, polyoxypropylene glycol, ethylene propylene glycol; ethyl cellosolve, butyl cellosolve, acetone, methoxypropanol, ethoxypropanol, other alkoxy alcohols, and the like. They may be used in an amount of 1 or 2 or more.

The amount of the solvent used in the step of forming the 2 nd coating layer (in the case of performing the preliminary dispersion of the metal particles, the amount of the solvent used is not particularly limited, but is usually 50 to 5000 parts by mass, more preferably 100 to 2000 parts by mass, relative to 100 parts by mass of the metal particles (solid content). The use of the solvent in an amount of 50 parts by mass or more can suppress the segregation of the molybdenum compound and the aggregation of the metal particles. In addition, the amount of the solvent used is 5000 parts by mass or less, whereby a sufficient treatment effect with the molybdenum compound on the metal particles can be obtained.

The temperature of the mixed solution when the mixed solution containing the metal particles and the molybdenum compound is stirred is usually about 10 to 100 ℃, and particularly preferably 30 to 80 ℃. By setting the temperature to 10 ℃ or higher, the reaction time for obtaining a sufficient treatment effect can be shortened. In addition, by setting the temperature to 100 ℃ or lower, the reaction for obtaining the desired composite metal pigment composition can be more easily controlled.

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

After the stirring of the mixed solution containing the metal particles and the molybdenum compound is completed, the particles having the 2 nd coating layer formed thereon can be recovered. In this case, if necessary, known washing, solid-liquid separation, and the like can be appropriately performed. For example, it is preferable to remove water and unreacted substances from a cake containing metal particles having a molybdenum-containing coating film by washing the mixed solution with a hydrophilic organic solvent and then filtering the washed solution with a filter or the like. Thus, a molybdenum-containing coating film as the 2 nd coating layer can be formed. In the case of forming the other 2 nd cover layer, the method may be performed as described above.

In the mode of forming the 2 nd coating layer (the molybdenum-containing coating film will be described below as an example) on the metal particles and then forming the metal oxide coating layer (the silicon-containing compound layer will be described below as an example), the particles on which the 2 nd coating layer is formed may not be recovered after the stirring of the mixed solution containing the metal particles and the molybdenum compound is completed, but in this system, the silicon compound source (typically, the organic silicon compound represented by the above formula (1), for example, tetraalkoxysilane and/or condensate thereof, and at least one of the silane coupling agents represented by the above formulas (2) to (4)) is directly added/stirred. In this case, a dispersion of the organosilicon compound represented by the formula (1), for example, tetraalkoxysilane and/or a condensate thereof may be added to a system including the particles having the coating layer of the 2 nd, and then a dispersion of at least one of the silane coupling agents represented by any one of the formulas (2) to (4) may be added and stirred.

Use of composite metallic pigment compositions

The composite metal pigment composition according to the application 1 and the composite metal pigment composition produced by the production method according to the application 2 and/or the application 3 can be used for organic solvent-based paints, inks, and the like. The composite metallic pigment composition can be added to an aqueous paint or an aqueous ink in which a resin as a coating film forming component (binder) is dissolved or dispersed in a medium mainly containing water, to thereby form a metallic aqueous paint or a metallic aqueous ink. The composite metal pigment composition may be kneaded with a resin or the like to be used as a water-resistant binder or filler. The antioxidant, light stabilizer, and surfactant may be added when the composite metallic pigment composition is blended into an aqueous paint, aqueous ink, resin, or the like.

In the case where the composite metallic pigment composition is used for a coating material or an ink, it may be directly added to a (aqueous) coating material or a (aqueous) ink, but is preferably added after being dispersed in a solvent in advance. Examples of the solvent used include water, dodecanol ester, diethylene glycol monobutyl ether, and propylene glycol monomethyl ether. Examples of these resins include acrylic resins, polyester resins, polyether resins, epoxy resins, fluorine resins, rosin resins, and the like. In addition, as an example of the binder for the paint or ink, rubber is mentioned in addition to resin.

These resins are preferably emulsified, dispersed or dissolved in water. For this purpose, carboxyl groups, sulfonic acid groups, and the like contained in the resins can be neutralized.

Preferred resins include acrylic resins and polyester resins.

If necessary, a resin such as a melamine-based curing agent, an isocyanate-based curing agent, or a urethane dispersion may be used in combination. Further, the pigment may be combined with a coloring pigment such as an inorganic pigment, an organic pigment, or an extender which is usually added to a paint, a silane coupling agent, a titanium coupling agent, a dispersant, a sedimentation inhibitor, a leveling agent, a thickener, or a defoaming agent. In order to improve dispersibility in the paint, a surfactant may be further added. In order to improve the storage stability of the paint, an antioxidant, a light stabilizer, and a polymerization inhibitor may be further added.

Examples of the coloring pigment include phthalocyanine, quinacridone, isoindolinone, perylene, azo lake, iron oxide, chrome yellow, carbon black, titanium oxide, and pearlescent mica.

The content of the composite metallic pigment composition of the application 1 or the composite metallic pigment composition produced by the production method of the application 2 or 3 in the aqueous paint or the aqueous ink (resin composition) is not limited, but may be usually 0.1 to 30% by mass, and particularly preferably 1 to 20% by mass. When the content is 0.1 mass% or more, a high decorative (metallic) effect can be obtained. Further, the content of 30 mass% or less can prevent deterioration of the properties of the aqueous paint or the aqueous ink, such as weather resistance, corrosion resistance, mechanical strength, and the like.

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

The method of applying or printing the aqueous paint and the like is not particularly limited. For example, various coating methods and printing methods can be appropriately employed in consideration of the form of the aqueous paint and the like, the surface shape of the material to be coated, and the like. Examples of the coating method include a spray method, a roll coater method, a brush coating method, and a doctor blade coating method. Examples of the printing method include gravure printing and screen printing.

The coating film formed by the aqueous coating material or the like may be formed on the undercoat layer or the intermediate coating layer formed by the electrodeposition coating or the like. In addition, a surface coating layer or the like may be formed on a coating film formed by an aqueous paint or the like as required.

In the case of these layer structures, each coating layer may be coated, or the next coating layer may be coated after curing or drying, or the next coating layer may be coated after each coating layer is coated by so-called wet-on-wet coating, without curing or drying. From the viewpoint of obtaining a coating film having good mirror-like brightness, a method comprising a step of forming a coating film layer by an aqueous coating material or the like after applying a primer layer and curing or drying is preferably employed for the aqueous coating material or the like containing the composite metallic pigment composition of the application 1 or the composite metallic pigment composition produced by the production method of the application 2 or 3.

The method of curing the coating composition in each coating layer may be either thermal curing or normal temperature curing. The method for drying the coating composition of each coating layer may be, for example, hot air or natural drying at ordinary temperature.

The thickness of the coating layer formed by the aqueous paint is not particularly limited, but is usually preferably about 0.5 to 100. Mu.m, more preferably about 1 to 50. Mu.m. The thickness of the coating layer is 0.5 μm or more, whereby the hiding effect of the substrate by the ink or paint can be sufficiently obtained. In addition, the thickness of the coating layer is 100 μm or less, whereby drying becomes easy, and occurrence of defects such as wrinkles and sagging can be suppressed.

The composite metal pigment composition according to the application 1, the composite metal pigment composition obtained by the production method according to the application 2 or 3, and the coating film obtained by using the same have excellent designability, gloss, suppression of particle generation, stability in aqueous coating materials, and the like at a high level, and therefore can be suitably used for various applications such as coating materials, inks, resin binders, and the like in which metal pigments have been conventionally used, more specifically, automobile bodies, automobile repair materials, automobile parts, home appliances, and the like, plastic parts, PCM coating materials, high weather resistance coating materials, heat resistant coating materials, anticorrosive coating materials, ship bottom coating materials, offset printing inks, gravure printing inks, screen printing inks, and the like.

Examples

The present invention will be described more specifically with reference to the following 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

In 1m of diameter 2m of anchor stirring wing with wing diameter 1m ² Is the inverse of (2)To a reaction vessel, 135kg of commercially available aluminum paste (trade name "GX-3100 (average particle diameter 11 μm, nonvolatile matter 74%)") was added 465kg of methoxypropanol (hereinafter abbreviated as "PM"), and the mixture was stirred at 100rpm with stirring blades, and the 10L/min dispersion withdrawn from the bottom was returned to the outside of the reaction vessel from the upper part of the reaction vessel, whereby the aluminum paste was uniformly dispersed in the PM. In the external circulation, 500W of ultrasonic waves were irradiated for 1 minute in the middle of the flow path, improving the dispersibility of the particles.

Next, phosphotungstopolybdic acid (H) ₃ PW ₆ Mo ₆ O ₄₀ ) 1kg of hydrate was dissolved in 5kg of methoxypropanol to obtain a liquid, and the liquid was stirred for 1 hour while maintaining the slurry at 40 ℃. In the reaction, the external circulation was continued while the ultrasonic wave was irradiated.

Then, as the organosilicon compound, 10kg of tetraethoxysilane was added, and then 10kg of 25% aqueous ammonia and 200kg of purified water were added over 3 hours. Then, as a silane coupling agent, 1.3kg of methyltrimethoxysilane was added thereto and stirred for 2 hours. In the reaction, the external circulation was continued while the ultrasonic wave was irradiated. After the reaction, the slurry was filtered under pressure after cooling.

The filtered slurry was purified using isopropyl alcohol (hereinafter abbreviated as "IPA")/PM: after the 3/2 mixture was sufficiently washed to replace the solvent, the mixture was again pressure-filtered and vented to volatilize mainly IPA, thereby obtaining a composite aluminum pigment composition having a nonvolatile content of 90%. The water content in the IPA/PM mixed solvent used herein was 200ppm, and dry air having a dew point of-40℃was used for the pressure filtration and ventilation.

Example 2

A composite aluminum pigment composition having a nonvolatile content of 90% was obtained in the same manner as in example 1 except that the composition was changed to an aluminum paste (trade name "GX-4100 (average particle diameter: 10 μm, nonvolatile content: 74%)", manufactured by Asahi Kabushiki Kaisha).

Example 3

A composite aluminum pigment composition having a nonvolatile content of 85% was obtained in the same manner as in example 1 except that the composition was changed to an aluminum paste (trade name "FD-5090 (average particle diameter 9 μm, nonvolatile content 75%)", manufactured by Asahi Kabushiki Kaisha).

Example 4

The reaction was carried out in the same manner as in example 1 until the completion of the reaction, and after cooling, the slurry was filtered, and washing and filtration were repeated 3 times with an equal amount of PM to obtain a paste having a nonvolatile content of 50%. Then, the solvent was volatilized at room temperature under reduced pressure, and after the non-volatile component was raised by 10%, the reduced pressure was released and mixed to homogenize the paste, and the paste was sealed and left for 12 hours. This operation was further carried out 2 times to obtain a paste-like composite aluminum pigment composition having a nonvolatile content of 90%.

Example 5

A composite aluminum pigment composition having a nonvolatile content of 90% was obtained in the same manner as in example 1, except that an IPA/PM mixed solvent having a water content of 2000ppm was used as the IPA/PM mixed solvent.

Comparative example 1

To 135kg of a commercially available aluminum paste (trade name "GX-3100 (average particle diameter 11 μm, nonvolatile content 74%)") was added 465kg of PM to disperse the mixture to obtain a slurry, and the slurry was stirred while adding phosphotungstomolybdic acid (H) ₃ PW ₆ Mo ₆ O ₄₀ ) 1kg of hydrate was dissolved in 5kg of PM, and the slurry was stirred for 1 hour while maintaining the temperature of the slurry at 40 ℃. Then, the slurry was filtered after cooling to obtain a composite aluminum pigment composition having a nonvolatile content of 60%.

Comparative example 2

A composite aluminum pigment composition having a nonvolatile content of 80% was obtained in the same manner as in example 1, except that the step of transferring the aluminum pigment composition after completion of the reaction and filtration was changed to a step of heating to 50 ℃ and reducing the pressure for 1 hour while keeping the aluminum pigment composition still.

Comparative example 3

A composite aluminum pigment composition having a nonvolatile content of 80% was obtained in the same manner as in example 1, except that the step of removing the solvent by pressing with a filter press was changed after the completion of the reaction and the filtration.

(evaluation of composite metallic pigment composition)

₅₀ Average particle diameter: d (D)

The average particle diameter (D) of composite particles (silica-coated aluminum particles) in the composite aluminum pigment compositions obtained in the above examples/comparative examples ₅₀ ) The particle size distribution was measured by a laser diffraction/scattering type particle size distribution measuring apparatus (LA-300/manufactured by horiba, inc.).

As the measurement solvent, isopropyl alcohol was used.

The measurement was carried out according to the machine instructions, and as a precaution, the composite metal pigment composition as a sample was subjected to ultrasonic dispersion for 2 minutes as a pretreatment, then put into a dispersion tank, and after confirming that the dispersion was at an appropriate concentration, the measurement was started.

After the measurement is completed, D ₅₀ Calculated by software of the machine and automatically represented.

Concentration of solid content

10g of the composite aluminum pigment composition obtained in each of the examples and comparative examples was heated at 105℃for 3 hours to volatilize the volatile components, and then the mass was measured, and the ratio was determined as the mass of the solid component.

Residues from the treatment of plant diseases

50g of the composite aluminum pigment composition obtained in each of the above examples/comparative examples was dispersed in 1000ml of mineral spirits by a spatula, then filtered through a 200-mesh nylon mesh (NBC Co.) and the residue was thoroughly washed with acetone, dried at 105℃for 10 minutes, and the mass was measured to determine the ratio as the mass of the residue.

(evaluation of paint and coating film)

Using the composite aluminum pigment compositions obtained in the examples and comparative examples, aqueous metallic paints were produced with the following compositions, and the paints and the coating films obtained therefrom were evaluated by the following methods. The results are shown in table 1.

An aqueous metallic paint having the following composition was produced.

Composite aluminum pigment composition: as a nonvolatile matter, 12.0g

Methoxy propanol: 18.0g

Polyoxyethylene lauryl ether (nonionic surfactant, manufactured by Sorbon oil and fat pharmaceutical Co., ltd., trade name "Marpon L5"): 6.0g

Purified water: 12.0g

Water-soluble acrylic resin (% 1): 110.0g

Melamine resin (+2): 18.0g

1: almatex WA911 manufactured by Mitsui chemical Co., ltd

2: nihon Cytec Industries manufactured by Inc. Cymel 350

After mixing the above components, the pH was adjusted to 7.7 to 7.8 with dimethylethanolamine, and the viscosity was adjusted to 650 to 750 mPas (B-type viscometer, no.3Low, 60 rpm, 25 ℃ C.) with a carboxylic acid-based thickener and purified water.

The aqueous metallic paint thus produced was used for the following evaluation.

Evaluation 1 (storage stability (gas production))

200g of the aqueous metallic paint prepared by the above formulation was collected in a flask, and the cumulative hydrogen generation amount was measured in a constant temperature water tank at 60℃until 24 hours. The gas generation amount was evaluated as an index of storage stability in the paint based on the obtained gas generation amount as the following standard.

O: less than 2ml

Delta: 2ml or more and less than 10ml

X: more than 10ml and less than 50ml

X×:50ml or more

Evaluation 2 (film evaluation)

The aqueous metallic paint prepared by the above formulation was air-spray-coated to form a dry film thickness of 6 μm on a 12cm×6cm steel sheet (manufactured by Miki coating K.K) to form a mid-coat paint, and after pre-drying at 90 ℃ for 10 minutes, the organic solvent type surface coating paint having the following composition was dispersed by a spatula for 3 minutes, and after adjusting the paint viscosity by a ford cup No. 4 to form 20.0 seconds, the air-spray-coated to form a dry film thickness of 20 μm was performed, and dried at 140 ℃ for 30 minutes to prepare a coated sheet, which was subjected to the following evaluation.

(composition of coating for organic solvent type surface coating)

ACRYCIC 44-179 (acrylic transparent resin manufactured by DIC Co., ltd.) 141g

SUPER BECKAMINE J-820 (Melamine resin manufactured by DIC Co., ltd.) 35.3g

Toluene 123.5g

2-i (coating film starting particles)

The number of particles formed on the entire surface of the surface coating film of the obtained coated sheet was measured and evaluated by the following index.

And (2) the following steps: can not see the particles

Delta: the number of particles is less than 10

X: more than 10 particles are formed

2-ii (brightness)

The obtained coated sheet was evaluated by using an Alcope コ line LMR-200, LTD. As an optical condition, a laser light source having an incident angle of 45 degrees and a light receiver having a light receiving angle of 0 degrees and-35 degrees were provided. As a measurement value, the IV value was obtained at a light receiving angle of-35 degrees, which gives the maximum light intensity, in addition to the light of the specular reflection region reflected on the surface of the coating film, among the reflected light of the laser light. IV is a parameter proportional to the intensity of the specular reflection light from the coating film, and indicates the magnitude of the brightness.

The IV values thus obtained were evaluated based on the following criteria.

And (2) the following steps: the magnitude of the decrease from the baseline (comparative example 1) was less than 20.

Delta: the reduction from the reference (comparative example 1) was 20 or more and less than 40.

X: the reduction from the reference (comparative example 1) was 40 or more.

2-iii (hidden)

The aqueous metallic paint thus produced was applied to a polyethylene terephthalate sheet (PET sheet) with a 2 mil applicator so as to form a dry film thickness of 15 μm, and the film was visually confirmed to be dried at 140 ℃ for 30 minutes.

O: is slightly lowered as compared with the standard (comparative example 1).

Delta: reduced compared to the reference (comparative example 1).

X: is greatly reduced compared with the reference (comparative example 1).

(evaluation of aggregation and deformation of composite particles)

In order to facilitate the determination of the aggregation state of particles, etc., the amount of aluminum paste in the compounding of the paint used in the production of the coated sheet in evaluation 2 was set to 1/10, and the paint was produced under the same conditions except that the coated sheet was produced under the conditions of evaluation 2.

The coated plate was cut into 1cm square pieces using a plate cutting machine.

The obtained coating film cross section was set using an ion milling apparatus (japan electronic system/IB-09010 CP) so that ion beam irradiation was possible until a portion separated from the coating film cross section by 20 μm was separated, and a precision polished cross section sample was produced by ion milling treatment.

The resulting coating film cross section (coated plate) was observed by FE-SEM (HITACHI system/S-4700), whereby the state of overlapping of particles and the state of deformation of particles were observed, and the evaluation was performed according to the following procedure.

Ratio of 1 st particles (aggregation state)

First, the degree of overlapping of particles can be easily determined and observed at a magnification of approximately 1000 to 3000 times. The degree of overlap cannot be distinguished by this magnification, and the magnification is appropriately changed, whereby the degree of overlap is evaluated. In this observation method, observation was performed at a magnification of approximately 30000 times at maximum. Multiple fields of view were observed from the same cross section of the sample piece so that the number of particles observed was 500 or more.

When the particles are close to each other and aggregation is difficult to determine, it is determined that aggregation is not occurring when the particle diameter of the particles (particles having a smaller major diameter) is 1/4 or less of the length of the contact portion between the particles, and it is determined that aggregation is occurring when the particle diameter is greater than 1/4.

Ratio of curved particles (deformed state)

The degree of deformation of the particles can be easily distinguished, and the deformation can be observed at a magnification of approximately 1000 to 3000 times. The degree of deformation was evaluated by appropriately changing the magnification in the case where deformation was not discernable at this magnification. In this observation method, observation was performed at a magnification of approximately 30000 times at maximum. Multiple fields of view were observed from the same cross section of the sample piece so that the number of particles observed was 500 or more. The presence or absence of deformation is determined as having a shortest distance between both ends of the particles of 0.8 times or less relative to the length of the particles.

Average particle thickness of metal particles

The thickness measurement and the average thickness calculation of the particles in the aluminum particle cross section were performed using the FE-SEM image (1 ten thousand times) obtained by the above-described obtaining step and the image analysis software Win Roof version 5.5 (manufactured by MITANI CORPORATION).

An FE-SEM image in which the thickness of the aluminum particles in the cross section was measured was displayed, and the ROI line was selected so as to match the ROI line with the 5 μm scale of the image, and the registration/change input length/unit was set.

Next, an image of the aluminum particle cross section to be measured for thickness is displayed, a rectangular ROI is selected, and 2-value processing is performed so that the rectangular ROI matches the cross section of the particle.

Next, after a measurement item of the measured vertical chord length is selected, measurement is performed, and an automatic measurement value (vertical chord length value) obtained by image analysis software is represented in an image.

Using the image analysis software Win Roof version 5.5, 300 particles were selected in this way, and automatic measurement of the thickness and the length of the aluminum particles in the cross section was performed. Then, an arithmetic average of the thicknesses of 300 particles was calculated, and the average thickness t of the particles was obtained. The aluminum particles have high uniformity in thickness and small differences in thickness due to the cut portions of the particles. The influence of the differences in the cut-off sites of the particles on the measurement of the average particle thickness is negligible.

Average particle thickness of composite particles, thickness of oxidized metal coating

For the above FE-SEM image, a coated plate used for the production was obtained, and the average thickness of the particle cover layer was measured at 20 ten thousand times using a STEM (scanning transmission electron microscope). When irregularities exist on the surface of the coating layer, the average thickness of the coating layer is obtained by measuring the area of the coating layer by dividing the circumference of the particles coated with the area by using image analysis software Win Roof version 5.5. In the case of large particles, it is not necessarily necessary to measure the entire area of the coating layer, and the area of the coating layer in the region of about 1 μm is measured along the particle surface and divided by the particle surface length, whereby the average thickness of the coating layer is obtained with sufficient accuracy. In addition, the average thickness of the coating layer was substantially uniform without depending on the particles, and thus an average value was obtained for 10 particles. The average particle thickness of the composite particles was determined from the thickness of the particle cover layer and the average particle thickness of the metal particles obtained as described above according to the following calculation formula.

Average particle thickness of composite particles = average particle thickness of metal particles + thickness of cover layer x 2[ table 1]

The evaluation results are shown in Table 1. The composite metal pigment composition of the present application satisfying all of the conditions of the above items (1) to (6) obtained in each example has a high solid content, has good stability as a coating material, generates little gas (has good storage stability), is excellent in brightness and concealing properties, and further effectively suppresses the occurrence of particles in a coating film.

Industrial applicability

The composite metal pigment composition according to the application 1, the composite metal pigment composition obtained by the production methods according to the application 2 and 3, and the coating film obtained by using them, are excellent in storage stability, particle suppression, design property, concealing property, and the like of coating films in low VOC, aqueous coating materials and the like at a high level beyond the limits of the prior art, and therefore, can be suitably used for various applications such as coating materials, inks, resin binders, and the like in which metal pigments have been conventionally used, more specifically, for various fields such as automobile bodies, automobile repair materials, automobile parts, home appliances, and the like, weather resistant coating materials, PCM coating materials, high-weather resistant coating materials, heat resistant coating materials, anticorrosive coating materials, ship bottom coating materials, offset printing inks, gravure printing inks, screen printing inks, and the like, and have high availability in various fields in industries such as the transportation machinery industry of automobiles, the electrical and electronic industry of home appliances, the coating industry, and the printing industry.

Claims

1. A composite metallic pigment composition containing composite particles having metallic particles and a metal oxide coating formed on the surfaces thereof,

(1) The composite particles are in the shape of scales,

(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%,

(6) The residue of the composite metal pigment composition when filtered by a 200-mesh filter is 0.1 mass% or less of the solid content,

at least 1 of the metal oxide caps is a silicon-containing compound layer.

2. The composite metallic pigment composition according to claim 1, wherein the composite particles have a shape factor of 30 to 700 as a ratio of the diameter to the thickness, i.e., an average particle diameter divided by an average thickness.

3. The composite metallic pigment composition according to claim 2, wherein the composite particles have a shape factor of 80 to 500 as a ratio of the diameter to the thickness, i.e., an average particle diameter divided by an average thickness.

4. The composite metal pigment composition according to claim 1, wherein the volume-based average particle diameter D at the time of measuring the particle size distribution of the composite particles by a laser diffraction type particle size distribution meter ₅₀ 3-20 μm.

5. The composite metallic pigment composition according to claim 1, wherein the composite particles have an average particle thickness of 20 to 200nm.

6. The composite metallic pigment composition according to any one of claims 1 to 5, wherein a solid content concentration of the composite metallic pigment composition is 85 to 95 mass%.

7. The composite metal pigment composition according to any one of claims 1 to 5, wherein the solvent having hydrophilicity and a boiling point of 80 to 150 ℃ accounts for 90 to 100 mass% of the non-solid component of the composite metal pigment composition.

8. The composite metal pigment composition according to any one of claims 1 to 5, wherein the residue obtained when the composite metal pigment composition is filtered through a 200-mesh filter is 0.005% by mass or less of the solid content.

9. The composite metal pigment composition according to any one of claims 1 to 5, wherein the ratio of the non-aggregated primary particles in the composite particles is 35% or more on a number basis.

10. The composite metallic pigment composition according to claim 9, wherein the proportion of non-aggregated primary particles in the composite particles is 50% or more on a number basis.

11. The composite metal pigment composition according to any one of claims 1 to 5, wherein the ratio of the curved composite particles in the composite particles is 10% or less on a number basis.

12. The composite metallic pigment composition according to claim 11, wherein the ratio of the curved composite particles in the composite particles is 3% or less on a number basis.

13. The composite metal pigment composition according to any one of claims 1 to 5, wherein the silicon content of the oxidized metal coating is 1 to 20 parts by mass relative to 100 parts by mass of the metal particles.

14. The composite metallic pigment composition of any of claims 1-5, wherein the metal oxide coating has an average layer thickness of from 5 to 200nm.

15. The composite metallic pigment composition according to claim 14, wherein the metal oxide coating has an average layer thickness of 20 to 70nm.

16. The composite metallic pigment composition according to any one of claims 1 to 5, wherein the metallic particles contain aluminum or an aluminum alloy.

17. The composite metal pigment composition according to claim 16, wherein 95 mass% or more of the metal particles are composed of aluminum element.

18. The composite metallic pigment composition of any of claims 1-5, wherein the composite particles further have: a coating layer containing at least one selected from the group consisting of a metal, a metal oxide, a metal hydrate, and a resin.

19. A process for producing a composite metallic pigment composition according to any one of claim 1 to 18, comprising the steps of 1) to 3),

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal,

20. A process for producing a composite metallic pigment composition according to any one of claim 1 to 18, comprising the steps of 1) to 3),

1) A step of dispersing the metal particles in a solvent,

2) A step of covering the metal particles with an oxidized metal,

the solvent volatile in step 3) is performed in 3 stages or more.

21. The method according to claim 19, wherein the solvent volatile in step 3) is performed in 3 stages or more.

22. The production method according to claim 19 or 20, wherein the solvent in step 3) has a water content of 10 mass% or less when the solvent is volatilized.

23. The method according to claim 22, wherein the solvent in step 3) has a water content of 1 mass% or less when the solvent is volatilized.