CN115216182A

CN115216182A - Composite metallic pigment composition and method for producing same

Info

Publication number: CN115216182A
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: 2022-10-21
Anticipated expiration: 2042-04-13
Also published as: KR20220142928A; JP2022163850A; CN115216182B

Abstract

A composite metallic pigment composition and a process for producing the same, wherein the composition has a high content of nonvolatile components (solid components), is excellent in dispersibility in a coating material, can form a coating film excellent in color tone, brightness, hiding property and the like, and can provide a coating material excellent in storage stability, and the properties are balanced at a high level. The composite metallic pigment composition comprises composite particles having metal particles and a metal oxide coating formed on the surfaces thereof, (1) the composite particles are in the form of flakes, and (2) the volume-based average particle diameter D is measured when the particle size distribution of the composite particles is measured ₅₀ 1 to 30 μm, (3) the composite particles have an average particle thickness of 20 to 300nm, (4) the composition has a solid content concentration of 70 to 95% by mass, and (5) the composition has hydrophilicity and a boiling point of 80A solvent at a temperature of about 150 ℃ accounts for 80 mass% or more of the non-solid content of the composition, and (6) a residue obtained when the composition is filtered through a 200-mesh filter is 0.1 mass% or less of the solid content.

Description

Composite metal pigment composition and method for producing same

Technical Field

The present invention relates to a composite metallic pigment composition containing composite particles having metal particles and an oxidized metal coating formed on the surface thereof, and more particularly, to a composite metallic pigment composition which effectively suppresses aggregation, deformation, and the like of the composite particles while reducing the amount of Volatile Organic Compounds (VOC), and which is balanced at a high level with excellent properties of a coating film such as storage stability, blocking of particles (japanese: 1250212484, cutting), design, hiding, and the like, used for low VOC, aqueous coatings, and the like, 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 a makeup effect in which a metallic feeling is emphasized.

In recent years, in the field of coating materials, there has been an increasing need for conversion of aqueous coating materials with a small amount of organic solvent as a measure for resource saving, improvement of working environment, and pollution-free property. In order to improve the stability of a metallic pigment in an aqueous coating material, for example, a pigment using composite particles in which metallic particles are covered with an oxidized metal such as amorphous silica has been proposed. Further VOC reduction is also required for such water-based coating materials. In order to reduce VOC, it is effective to improve the nonvolatile content (solid content) in the production process, and therefore, if strong centrifugal separation, pressurization under strong pressure, or filtration is performed in the filtration process, metal particles such as aluminum are deformed or aggregated, and defects are generated in the oxide metal coating such as silica, which may deteriorate the water resistance and reduce the storage stability. In addition, although the nonvolatile content can be improved by evaporating the solvent by heating and reducing the pressure, the surface is dried at an early stage and the particles are adhered to each other and aggregated, and thus the particles cannot be dispersed in the solvent or water without aggregation. The composite metallic pigment composition having the nonvolatile content improved by the conventional method has problems such as poor dispersibility during coating production, inability to express a desired color tone, and poor storage stability, and there is a strong demand for solving such problems.

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

Patent document 2 describes that suction filtration is performed using a buchner funnel in the production of a coated aluminum effect pigment, and that an aqueous coating system is formed using the aluminum effect pigment, but no report is made as to whether the dispersibility is good or not.

Documents of the prior art

Patent document

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 above-described limitations of the prior art, an object of the present invention is to provide a composite metallic pigment composition having a high nonvolatile content (solid content), which is excellent in dispersibility in a coating material, particularly an aqueous coating material, and which can form a coating film having excellent color tone, brightness, hiding property, and the like, and which is excellent in storage stability, and which is well balanced in these properties, and a method for producing the same.

Means for solving the problems

The present inventors have intensively studied and 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 volatilizing the solvent under specific conditions in the production of the composite metal pigment composition, and thus completed the present invention.

That is, the invention 1 and its various aspects are as follows.

[1] A composite metallic pigment composition containing a composite particle having a metal particle and an oxidized metal coating formed on the surface thereof,

(1) The shape of the composite particles is a scale shape,

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

(3) The composite particles have an average particle thickness of 20 to 300nm,

(4) The solid content concentration of the composite metallic pigment composition is 70 to 95% by mass,

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

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

[2] The composite metallic pigment composition according to item [1], wherein the composite particles contain primary particles that are not aggregated in a proportion of 35% or more on a number basis.

[3] The composite metallic pigment composition according to item [1] or [2], wherein a ratio of the bent composite particles in the composite particles is 10% or less on a number basis.

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

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

[6] The composite metallic 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 particle further comprises: and a coating layer containing at least one selected from the group consisting of a metal, a metal oxide, a metal hydrate, and a resin.

The invention of the present application 2, 3 and various embodiments thereof are as follows.

[8] A process for producing a composite metallic pigment composition, which comprises 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,

3) A step of washing, filtering and volatilizing the solvent the composite particles having the metal particles and the oxidized metal coating formed on the surfaces thereof obtained in the step 2),

the solvent in the step 3) is a mixed solvent of 2 or more solvents having compatibility with each other and having 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 process for producing a composite metallic pigment composition, which comprises 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 volatilization in step 3) is carried out in 3 stages or more.

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

ADVANTAGEOUS EFFECTS OF INVENTION

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

The composite metallic pigment composition of the invention 1 of the present application can effectively suppress aggregation, deformation, and the like of the composite particles while reducing the amount of Volatile Organic Compounds (VOC), and can form a balance at a high level exceeding the limit of the conventional art in terms of excellent properties of the coating film such as storage stability, suppression of particle generation, design properties, hiding properties, and the like when used in low VOC, aqueous coating materials, and the like.

According to the production methods of the present invention 2 and 3, it is possible to efficiently produce a composite metallic pigment composition which is reduced in the amount of Volatile Organic Compounds (VOC), effectively suppresses aggregation, deformation, and the like of composite particles, and has a balance of high levels, such as excellent properties of a coating film, including storage stability, suppression of generation of particles, design properties, and hiding properties, which are used for low-VOC, water-based coating materials, and the like, exceeding the limits of the conventional art.

Detailed Description

The present invention will be described below with reference to typical or preferred embodiments, but the present invention is not limited to these embodiments. These embodiments may be freely combined within the scope of the invention, which is defined by the appended claims, unless explicitly stated otherwise.

The invention of the present application 1 is a composite metallic pigment composition containing a composite particle having a metal particle and an oxidized metal coating formed on the surface thereof,

(1) The shape of the composite particles is a scale shape,

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

(3) The composite particles have an average particle thickness of 20 to 300nm,

(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 content of the composite metallic pigment composition,

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

Composite particles constituting composite metal pigment composition

The composite metallic pigment composition of invention 1 of the present application contains composite particles having a metal particle and an oxidized metal coating formed on the surface thereof.

That is, in the present specification, the term "composite metallic pigment composition" contains a composite particle having a metal particle and an oxidized metal coating formed on the surface thereof as an essential component, and further contains a specific non-solid component.

The composite metallic pigment composition of the present invention 1 may contain other components such as an organic treating agent, a solvent containing water and/or a hydrophilic solvent.

Metal particles

The composite particle constituting the composite metallic pigment composition of the invention of the present application 1 comprises a metal particle and an oxidized metal coating formed on the surface thereof. That is, 1 or more layers of oxidized metal coating are formed on the surface of the metal particle serving as the core of the composite particle. The oxidized metal cap 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 metallic pigments, such as aluminum, aluminum alloys, zinc, iron, magnesium, nickel, copper, silver, tin, chromium, stainless steel, and the like. In the present specification, the metal constituting the metal particles of the composite particles includes not only a simple metal but also an alloy and an intermetallic compound.

The metal particles may be used alone in 1 kind or in combination of 2 or more kinds.

The metal particles in the invention 1 of the present application preferably contain aluminum or an aluminum alloy, and more preferably 95 mass% or more of the metal particles are composed of an 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 described later is preferably achieved ₅₀ The average particle diameter of (3). That is, D in the case of measuring the volume distribution of the composite particles by means of a laser diffraction particle size distribution meter is preferable ₅₀ 1 to 30 μm or so as to easily form D ₅₀ The volume average particle diameter (D) of the metal particles is set 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 or the like, the mass of each 1 grinding ball when using a ball mill, the rotation speed of a grinding apparatus, the degree of screening and filter press, and the like in the step of grinding and screening/filtering the raw material atomized metal powder (for example, aluminum powder) or the like using a ball mill or the like.

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

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

Here, the average particle thickness of the metal particles can be measured by a method known in the art, and for example, can be measured by forming a coating film using a metal pigment composition containing composite particles having metal particles and an oxidized metal coating formed on the surface thereof, obtaining an FE-SEM image (field emission type scanning electron microscope image) of the 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 the thickness (shape factor obtained by dividing the average particle diameter by the average thickness) of the flaky metal particles is preferably 30 to 1500, more preferably 50 to 1000, and particularly preferably 80 to 700. When the ratio of the diameter to the thickness of the metal particles is 30 or more, a higher luminance can be obtained. Further, when 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 D of metal particles ₅₀ Similarly, the particle size of the raw material atomized metal powder, the mass of each 1 grinding ball in the case of using a ball mill, the rotation speed of the grinding apparatus, and the process of the screening and filter press can be appropriately adjusted in the step of grinding and screening/filtering the raw material atomized metal powder (for example, aluminum powder) using a ball mill or the likeDegree, etc.

The metal particles do not necessarily need to be composed of only metal, and particles of synthetic resin, particles of inorganic particles such as mica and glass, and the like, the surfaces of which are covered with metal, may be used as long as the effects of the invention of claim 1 are not impaired. In the invention 1 of the present application, particles containing aluminum or an aluminum alloy are preferable from the viewpoints of, in particular, high weather resistance, small specific gravity, ease of obtaining, and the like.

The metal particles constituting the composite particles are particularly preferably aluminum flakes which are generally used as metal pigments. As the aluminum flakes, those having surface properties, particle diameters and shapes required for metallic pigments, such as surface glossiness, whiteness and luster, are suitable. Aluminum flakes are generally commercially available in a paste state. The paste-like aluminum flakes may be used as they are, or may be used by removing fatty acids from the surface in advance with an organic solvent or the like. In addition, the volume average particle diameter (D) can also be used ₅₀ ) 3 to 20 μm and an average thickness (t) of 10 to 110 nm.

Metal oxide coating

The composite particles constituting the composite metallic pigment composition of the invention of the present application 1 have an oxidized metal coating formed on the surface of the metal particles.

The metal oxide coating is a coating film formed of a layer containing a metal oxide, and may be formed on the entire surface of the metal particle or only a part of the surface. It is preferably formed on the entire surface from the viewpoint of water resistance, storage stability in the case of using in a coating material, and the like.

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

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

Therefore, the oxidized metal may be a metal oxide in a narrow sense in which only oxygen and at least one metal element are the constituent elements thereof, but as long as the constituent elements thereof contain oxygen and at least one metal element, elements other than the oxygen and the metal element may be contained in the constituent elements thereof, and may be, for example, a hydroxide, an oxide hydrate, an oxynitride, or the like of a metal. In addition, the compound may contain an organic group.

The metal oxide may be a so-called single oxide in which only 1 metal element is a constituent element, or may be a composite oxide in which 2 or more metal elements are constituent elements.

At least one metal element which is a constituent element of the metal oxide may be a typical metal or a transition metal. Further, the metal element may be a so-called semimetal element. Among them, a metal oxide containing silicon as a constituent element is particularly preferable as the metal oxide constituting the metal oxide coating.

Preferred 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 a mixture thereof, and an oxide hydrate and a hydroxide thereof are preferably used. Silicon oxides such as silicon oxide, silicon hydroxide, and/or silicon oxide hydrate can be used particularly preferably.

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

The metal oxide coating is generally a layer formed of a compound having an Si — O-bond (siloxane bond) by using silicon oxide as the metal oxide coating. Examples of such a layer include a layer containing at least one of a silane compound and a silicon oxide. As such a compound, in addition to the silane-based compound [ H ] ₃ SiO(H ₂ SiO) _n SiH ₃ ](wherein n represents an arbitrary positive integer), siO can be exemplified ₂ 、SiO ₂ ·nH ₂ O (wherein n represents an arbitrary positive integer)) Etc. of silicon oxide. These silane-based compounds and silicon oxides may be either crystalline or amorphous, and are particularly preferably amorphous. Therefore, as a 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 silicon oxide may be a layer formed using an organosilicon compound (containing a silane coupling agent) as a starting material. In this case, the metal oxide coating may contain an unreacted organosilicon compound or a component derived therefrom within a range that does not inhibit the effect of the invention 1 of the present application. 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 a silicon oxide is used is not particularly limited, and is preferably 1 to 20 parts by mass, and more preferably 2 to 15 parts by mass, per 100 parts by mass of the metal particles. By setting the silicon content of the oxidized metal coating to 1 part by mass or more per 100 parts by mass of the metal particles, the composite metal pigment composition can maintain high corrosion resistance, water dispersibility, stability, and the like. When the silicon content of the oxidized metal coating is 20 parts by mass or less with respect to 100 parts by mass of the metal particles, the composite particles can be prevented from being aggregated, and from being deteriorated in color tone such as hiding property and metallic luster.

The metal oxide coating of the composite particles contained in the composite metallic pigment composition according to claim 1 of the present application is particularly preferably hydrophilic. The composite particles are usually in the form of a composite metal pigment composition dispersed in an aqueous solvent (water or a mixed solvent containing water and an organic solvent), and when the metal oxide coating has a hydrophilic surface, the composite particles can be highly dispersed in such an aqueous solvent. Further, since a metal oxide such as silicon oxide (amorphous silica or the like) is very stable in an aqueous solvent, a composite metal pigment containing highly stable composite particles in an aqueous solvent can be provided. From such a viewpoint, it is preferable that at least 1 layer, preferably the outermost layer, of the composite particles contained in the composite metallic pigment composition of the invention 1 of the present application is an oxidized metal coating film, and particularly preferable is a silicon-containing compound layer (particularly a layer composed of a compound having an Si — O bond). Since the metal oxide has excellent affinity with the metal particles, when the composite particle has a coating layer composed of a plurality of layers, a metal oxide layer, particularly preferably a silicon-containing compound layer (particularly, si — O-based coating layer), may be formed separately as a layer other than the outermost layer, particularly preferably a layer in contact with the metal particles, in addition to the outermost metal oxide coating layer.

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

The thickness of the silicon-containing compound layer when the silicon-containing compound layer is contained in the metal oxide coating of each composite particle is also not particularly limited as long as the average thickness of the composite particles is in the range of 2 to 300nm as 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 will be further described 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 of the following general formulae (2), (3) and (4) and partial condensates thereof.

Si(OR ¹ ) ₄ (1)

(in the formula, R ¹ Is a hydrogen atom or a hydrocarbon group of 1 to 8 carbon atoms, R ¹ When the number of the particles is 2 or more, they may be all the same, some of them may be the same, or all of them may be different. )

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 which may optionally contain a halogen group, R ³ Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R is ² And R ³ Which may be the same or different, R ² Or R ³ When the number of the particles is 2 or more, they may be all the same, some of them may be the same, or all of them may be different. 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 Being a group containing reactive groups capable of chemically bonding to other functional groups, R ⁵ Is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may optionally contain a halogen group, R ⁶ Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R ⁴ 、R ⁵ Or R ⁶ When the number of the particles is 2 or more, they may be all the same, some of them may be the same, or all of them may be different. 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)

(in the formula, R ⁷ Is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms and optionally containing a halogen group, R ⁷ When the number of the particles is 2 or more, they may be all the same, some of them may be the same, or all of them may be different. 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 in (1) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group, and these may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl groups are particularly preferable. In addition, 4R ¹ May be all the same, some the same, or all different.

Preferred 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 in (b) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl and naphthyl groups, which may be branched or linear and may contain a halogen group such as fluorine, chlorine and bromine. Among them, a hydrocarbon group having 1 to 18 carbon atoms is particularly preferable. In addition, R ² When the number of the particles is 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 The number of (a) is 1 to 3, that is, m =1 to 3 in formula (2), but m =1 or 2 is more preferable.

R as formula (2) ³ Examples of the hydrocarbon group in (1) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group, and these may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl groups are particularly preferable. In addition, R ³ When the number of the particles is 2 or more, they may be all the same, some of them may be the same, or all of them may be different.

Preferred examples of the organosilicon compound (silane coupling agent) of the formula (2) include methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, trimethylmethoxysilane, trimethylethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltributoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltributoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldibutoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dioctyldimethoxysilane, dioctylethoxybutyloxysilane, decyltrimethoxysilane, decyltriethoxysilane, didecyldimethoxysilane, didecyldiethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, dioctadecyltrimethoxysilane, phenyltrimethoxysilane, tridecyltrimethoxysilane, 3-trifluoropropyltrimethoxysilane, 3-octylchloropropyltrimethoxysilane, 3-trifluoromethyltrimethoxysilane, heptadecyltrimethoxysilane, 3-trifluoromethylchloropropyltrimethoxysilane, 3-trifluoromethylchloropropyltrimethoxysilane, dioctadecyltrimethoxysilane, octadecyltrimethoxysilane, 3-trichlorotrimethoxysilane, heptadecyltrimethoxysilane, 3-octyltrimethoxysilane, heptadecafluorochloropropyltrimethoxysilane, heptadecyltrimethoxysilane, and the like, 3-chloropropyltributoxysilane and the like.

R as formula (3) ⁴ Examples of the reactive group in (3) include a vinyl group, an epoxy group, a styryl group, a methacryloxy group, an acryloxy group, an amino group, an ureido group, a mercapto group, a polysulfide (polysulfide) group, and an isocyanate group.

In addition, R ⁴ When the number of the cells is 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 The number of (b) is 1 to 3, i.e., p =1 to 3 in formula (3), but p =1 is more preferable.

R as formula (3) ⁵ Examples of the hydrocarbon group (b) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl and naphthyl groups, which may be branched or linear and may contain a halogen group such as fluorine, chlorine and bromine. Among them, a hydrocarbon group having 1 to 18 carbon atoms is particularly preferable. In addition, R ⁵ When the number of the particles is 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 in (1) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group, and these may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl groups are particularly preferable. In addition, R ⁶ When the number of the particles is 2 or more, they may be all the same, some of them may be the same, or all of them may be different.

Preferred examples of the organosilicon compound (silane coupling agent) of the formula (3) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, p-vinyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylpropyltrimethoxysilane, N-2-aminopropyl-2-aminopropylmethyldiethoxysilane, N-3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -2-aminopropyl-aminoethyltrimethoxysilane, 3-triethoxysilyl-N- (1, 3-dimethyl-butylidene) propylamine, 3-ureylpropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyl-triethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, etc.

R as formula (4) ⁷ Examples of the hydrocarbon group in (b) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl and naphthyl groups, which may be branched or linear and may contain a halogen group such as fluorine, chlorine and bromine. Among them, a hydrocarbon group having 1 to 12 carbon atoms is particularly preferable. In addition, R ⁷ When the number of the particles is 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 The number of (a) is 0 to 3, that is, r =0 to 3 in formula (4), but r =1 to 3 is more preferable.

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

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

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

As a raw material for the hydrolysis reaction and/or the condensation reaction of the hydrolysate and/or the condensation product thereof for obtaining the 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 in a separate step with replacement of the catalyst as needed. At this time, heating may be performed as necessary.

Physical Properties of composite particles and composite Metal pigment composition

The composite metallic pigment composition of the invention 1 of the present application satisfies the following physical property conditions for the composite particles constituting the composition.

(1) The shape of the composite particles is scaly.

(2) Volume-based average particle diameter D when particle size distribution of composite particles is measured by a laser diffraction particle size distribution meter ₅₀ Is 1 to 30 μm.

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

The composite metallic pigment composition according to claim 1 of the present application 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 content of the composite metal pigment composition.

These physical property conditions are described below.

(1) The shape of the composite particles is scaly.

The composite metal pigment composition of the invention 1 of the present application contains composite particles having a scaly shape. The composite metallic pigment composition of the invention 1 of the present application can effectively form a coating film having excellent characteristics such as high hiding power by containing the flaky composite particles.

The scaly composite particles are easily deformed in the steps of stirring, separation, filtration, etc. at the time of production, and particularly tend to be easily deformed by strong centrifugal separation for increasing the nonvolatile content (solid content), filtration under strong pressure, etc., but in the present invention, the deformation of the scaly composite particles can be effectively suppressed while achieving a high nonvolatile content (solid content).

Here, the composite particles are in the form of flakes, which means that the particles have a shape having a high aspect ratio preferably within a numerical range described later.

The scale-like composite particles can be produced by using scale-like 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 scaly composite particles contained in the composite metallic pigment composition according to claim 1 of the present application preferably have a aspect ratio (shape factor obtained by dividing an average particle diameter by an average thickness) of 30 to 700. When the diameter/thickness ratio of the composite particles is 30 or more, a higher luminance can be easily obtained. Further, when the aspect ratio of the composite particles is 700 or less, 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 the measurement of particle size distribution of composite particles by means of a laser diffraction particle size distribution meter ₅₀ Is 1 to 30 mu m

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

From the viewpoint of obtaining excellent design properties, gloss, suppression of particle generation, stability in an aqueous coating material, and the like, the volume-based D in the measurement of the particle size distribution of the composite particles by a laser diffraction particle size analyzer ₅₀ Preferably 2 to 25 μm, particularly preferably 3 to 20 μm.

The "composite particle" 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 in the particle size distribution of the composite particles was measured by a laser diffraction particle size distribution meter ₅₀ Refers to the particle size at 50% of the cumulative degree of integration in the volume cumulative particle size distribution. The laser diffraction particle size distribution meter is not particularly limited, and for example, "LA-300" (manufactured by horiba, ltd.) can be used. As the measurement solvent, a hydrophilic solvent such as water, isopropyl alcohol, or methoxypropanol can be used. For example, the composite metallic 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 composite metallic pigment composition is properly dispersed, D can be measured ₅₀ 。

Volume-based D of composite particles constituting composite Metal pigment composition ₅₀ E.g. ofThe particle size and the amount of the raw atomized metal powder, the amount of grinding solvent such as mineral spirits, the type and the amount of grinding aid, the mass and the amount of grinding balls per 1 ball when using a ball mill, the number of revolutions of a grinding device, the degree of sieving and a filter press, and the like can be controlled by appropriately adjusting the particle size and the amount of the raw atomized metal powder, the amount of grinding solvent such as mineral spirits, the type and the amount of grinding aid, the mass and the amount of grinding balls per 1 ball when using a ball mill, the number of revolutions of a grinding device, the degree of sieving and a filter press, and the like, and the particle size, the concentration, the stirring temperature, the stirring time, the type of a stirring device, the power and the degree of stirring (the type and the diameter of a stirring blade, the number of revolutions, the presence or absence of external stirring, and the like) and the like can be controlled by appropriately adjusting the pH, the concentration, the stirring temperature, the type, the degree of stirring device, the like when covering with an oxidized metal oxide (and the other covering layer as necessary).

Further, although the particle size tends to be large due to aggregation during the oxidized metal coating treatment, since the particle size is large to cause a decrease in color tone, a decrease in hiding property, and a decrease in appearance of a coating film, it is effective to prevent the particle size from being large by the pretreatment of the raw aluminum paste used particularly in the treatment.

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

The composite metallic pigment composition according to claim 1 of the present application contains composite particles having an average thickness of 20 to 300nm. In this way, in combination with the satisfaction of the above conditions (1) and (2), aggregation and deformation of the composite particles are effectively suppressed, and excellent design properties, gloss, suppression of particle generation, stability in the aqueous coating material, 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, respectively, and calculated from them according to the following formulas.

Average particle thickness of the composite particles = average particle thickness of the metal particles + thickness of the metal oxide coating × 2

The average particle thickness of the metal particles can be measured by the method described in the above (2).

The thickness of the oxidized metal coating can be measured by methods known in the art, for example, by STEM (scanning transmission electron microscope). More specifically, the measurement can be carried out by the method described in examples of the present application.

Average thickness and volume basis D of composite particles contained in composite metallic pigment composition ₅₀ Similarly, the pH, concentration, stirring temperature, stirring time, type of stirring device, and stirring power and degree (such as type and diameter of stirring blade, rotation speed, and presence or absence of external stirring) of the raw material aluminum paste at the time of hydrolysis of the raw material such as the organosilicon compound can be controlled by appropriately adjusting the pretreatment of the raw material aluminum paste, the step of coating with an oxide metal such as a silicon-containing compound layer (and if necessary, another coating layer), and the like. Further, although the particle size tends to be large due to aggregation during the oxidized metal coating treatment, since the particle size is reduced to decrease the color tone, decrease the concealing property, and decrease the appearance of the coating film, it is effective to prevent the particle size by the pretreatment of the raw material aluminum paste used particularly in the treatment.

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

The composite metallic pigment composition according to claim 1 of the present application has a solid content concentration of 70 to 95% by mass.

The composite metallic pigment composition according to claim 1 of the present application can realize a coating material which can form a coating film having a good appearance while achieving a low VOC (volatile organic compound) by setting the solid content concentration to 70 to 95 mass%. More specifically, since the content of VOC such as solvent can be sufficiently reduced by setting the solid content concentration to 70 mass% or more, even when a coating material is formed using the coating material, a coating material having a sufficiently reduced VOC content can be realized. On the other hand, when the solid content concentration is 95% by mass or less, uniform dispersion is facilitated when a coating material is formed, and generation of particles in the 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, and 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 content) 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 heating a predetermined amount of the composite metal pigment composition to volatilize the volatile component and determining the ratio of the mass to the mass before heating. More specifically, the measurement can be carried out, for example, by the method described in the examples of the present application.

The solid content concentration of the composite metallic pigment composition can be appropriately adjusted by removing volatile components such as a solvent used for dispersing the metal particles or forming the metal oxide coating by filtration, volatilization or the like at the time of producing the composite metallic pigment composition.

In the invention 1 of the present application, in order to achieve a specific high solid content concentration, it is preferable to use a low boiling point solvent which is easily removed by volatilization. Since such a low boiling point solvent may not be necessarily suitable for the dispersion of the metal particles and the formation of the metal oxide film, the solvent substitution for a lower boiling point solvent may be performed after the dispersion of the metal particles and the formation of the metal oxide film.

It is also preferable to evaporate the solvent in stages, and for example, after evaporation, the composite particles may be dispersed in the solvent and evaporated again.

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

Although a high solid content can be achieved by removing the solvent or the like by centrifugation or filtration under a relatively strong pressure, it should be noted that this operation causes aggregation and/or deformation of the scale-like composite particles, and it may be difficult to achieve other conditions of the invention 1 of the present application, for example, a predetermined volume-based average particle diameter D ₅₀ And a predetermined amount of residue.

In the invention of claim 1, the production method of the invention of claim 2 and/or the production method of the invention of claim 3 are particularly preferably used from the viewpoint that when the concentration of the solid content is specified, the aggregation and deformation of the composite particles are effectively prevented and the volatile component can be sufficiently removed.

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

The solvent (hereinafter, also referred to as "specific solvent") which is hydrophilic and has a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid content of the composite metallic pigment composition according to claim 1 of the present application.

Since the specific solvent has a boiling point of 80 to 150 ℃ and is easily volatilized, and an extremely high temperature and a reduced pressure are not required for volatilization, the specific solvent accounts for 80 mass% of the non-solid components, and thus the non-solid components such as the solvent can be removed without causing aggregation and adhesion of the composite particles to each other, and the solid content can be improved.

In addition, since the specific solvent is hydrophilic, it becomes easier to disperse the composite metallic pigment composition of the invention 1 in water and to form a uniform water-based paint by making the specific solvent account for 80 mass% of the non-solid content. Further, the hydrophilic property makes it easier to remove water in the composition by azeotropy or the like, and aggregation due to moisture can be more effectively suppressed.

The concept of a hydrophilic solvent is commonly understood by those skilled in the art, and for example, a solvent having a solubility in water of 20g/g or more at ordinary temperature can 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 contained in an amount of 80 to 100% by mass, more preferably 85 to 100% by mass, and particularly preferably 90 to 100% by mass, based on the non-solid content 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 metal pigment composition. The amount (ratio) of the specific solvent can be usually calculated from the amount of each solvent used in the production of the composite metallic pigment composition and the amount of each solvent removed, but when the steps such as filtration and volatilization in the production are complicated and difficult to calculate, the amount (ratio) of the specific solvent can be measured from the obtained composite metallic pigment composition by using a solvent extraction solvent such as THF (tetrahydrofuran), or by using LC-MS (liquid chromatography mass spectrometer).

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 metallic pigment composition of invention 1 of the present application is filtered through 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 the average particle diameter D on a volume basis ₅₀ The composite particles having an average particle thickness of 20 to 300nm and a particle size of 1 to 30 μm pass through a 200-mesh filter in most cases when no particles adhere to each other or aggregate. Therefore, the residue obtained when the composite metallic pigment composition is filtered through a 200-mesh filter is preferably a composite particle in which particles are adhered to each other and aggregated, and the ratio of the residue to the solid content is preferably low,

The composite metallic pigment composition according to claim 1 of the present application can effectively suppress the adhesion and aggregation of particles because the residue obtained by filtration through a 200-mesh filter is 0.1 mass% or less of the solid content, can form a coating material in which the aggregation is suppressed by dispersion in a solvent or water, and can form a coating film having an excellent appearance such as the effective suppression of the aggregation of particles.

The amount of the residue obtained by filtration through 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, based on the solid content.

The amount of the residue obtained by filtration through a 200-mesh filter can be determined by dispersing the composite metallic pigment composition in a solvent satisfactorily, then filtering through a 200-mesh filter, measuring the dry mass of the residue, and determining the ratio of the residue to the solid content from the mass of the residue and the initial solid content in the composite metallic pigment composition. More specifically, the measurement can be performed by, for example, the method described in examples of the present application.

The amount of residue obtained by filtration with a 200-mesh filter can be reduced by suppressing adhesion and aggregation of composite particles by various methods described in the present specification. In particular, the use of a large amount of the above-mentioned specific solvent is effective for reducing the amount of residue. Further, according to the production method of the invention 2 and/or 3, it is effective to remove volatile components while effectively preventing aggregation and deformation of the composite particles, and to reduce the amount of residue.

Preferable physical Properties of the composite particles

The composite metallic pigment composition according to claim 1 of the present application preferably has composite particles that have some or all of the following properties and characteristics, in addition to the physical properties conditions (1) to (3) described above.

The proportion of non-aggregated primary particles in the composite particles is 35% or more on a number basis

In the composite metallic pigment composition of the present embodiment, the ratio of the primary particles that are not aggregated to the total composite particles contained in the composite metallic pigment composition is preferably 35% or more by number. A ratio of primary particles of 35% or more means that the aggregation of each particle is suppressed, and the degree of aggregation is smaller not only for the primary particles but also for the aggregated particles. Thus, a coating film formed using the composite metallic pigment composition exhibits excellent design properties, gloss, suppression of particle generation, and further easily improves stability in an aqueous coating material.

In addition, since the aggregation of the respective particles is suppressed in this way, 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 primary particles that are not aggregated in the aggregate of composite particles is more preferably 40% or more, and particularly preferably 50% or more on a number basis.

The ratio of non-aggregated primary particles to the composite particles is generally higher and more preferable, and particularly, there is no upper limit, and it is desirable that the ratio is 100%.

The ratio of primary particles not aggregated in the composite particles can be determined 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 an oxidized metal coating on the surface thereof, obtaining an FE-SEM image (field emission scanning electron microscope image) of the cross section thereof for image analysis, or by an evaluator counting the number of primary particles and aggregated particles in the FE-SEM image. More specifically, the measurement can be performed by, for example, the method described in examples of the present application.

The ratio of the primary particles not aggregated to the composite particles can be improved by, for example, increasing the amount of the specific solvent to be used, using the production method of the invention 2, and/or the invention 3.

The selection and treatment of the metal particles constituting the composite particle, the type of the metal oxide coating formed on the metal particles, and the production conditions can be controlled by appropriately setting. As a conventional technique, there has been an attempt to enhance mechanical dispersion by increasing the stirring rotation speed during the coating treatment to a reynolds number equal to or higher than a certain value, but this method has the following problems: the dispersion of such fine particles is limited for the treatment in the present application, and the scale-like thin particles are broken or deformed due to a 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, and the ratio of primary particles that are not aggregated can be greatly increased.

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

Since the dispersibility of the metal particles themselves is improved by these treatments, the primary particles can be produced without being aggregated by mild stirring without requiring undue stirring during the coating treatment. Therefore, the deformation of particles during the coating treatment can be greatly reduced, and excellent design properties, gloss, suppression of particle generation, stability in the aqueous coating material, and the like in the coating film can be easily achieved.

In addition to the above, as the factors affecting the ratio of primary particles not aggregated, the particle size of the raw material atomized metal powder or the like in the step of grinding and sieving/filtering the raw material atomized metal powder (for example, aluminum powder) or the like by using a ball mill or the like, the mass per 1 grinding ball in the case of using a ball mill, the rotation speed of a grinding device, the degree of sieving and a filter press, and the pH, concentration, stirring temperature, stirring time, the type of a stirring device, and the power/degree of stirring (the type and diameter of a stirring blade, the rotation speed, presence or absence of external stirring, etc.) at the time of hydrolysis of the raw material such as an organic silicon compound in the step of covering with an oxide metal such as a silicon-containing compound layer (and if necessary, other covering layer) can be used, and the ratio of primary particles not aggregated can be controlled by appropriately adjusting them.

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

In the composite metallic pigment composition of the present embodiment, the ratio of the bent composite particles to the total composite particles contained in the composite metallic pigment composition is preferably 10% or less. Thus, a coating film formed using the composite metallic pigment composition exhibits excellent design properties, gloss, suppression of particle generation, and further easily improves stability in an aqueous coating material.

The ratio of the bent composite particles is understood as an index relating 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 no oxide metal coating is formed) of each composite particle is reduced, whereby stability in the aqueous coating material is improved, and further uniform and sufficient coverage is easily formed on each particle, whereby the aggregation property of each particle is further reduced, and therefore a coating film exhibiting excellent design properties, gloss, and particle suppression on the surface of a coating film formed using the composite metallic pigment composition can be obtained.

The smaller the ratio of the bent composite particles to the aggregate of the composite particles, the better. This ratio is preferably 6% or less, more preferably 3% or less. The lower the proportion of the bent composite particles, the more preferable, and therefore the lower limit thereof is not particularly present, and 0% is desirable.

The ratio of the bent composite particles in the composite metallic pigment composition can be measured by a method known in the art, and for example, can be measured by forming a coating film using a metallic pigment composition comprising an aggregate of composite particles having a metallic particle and an oxidized metal coating on the surface thereof, obtaining an FE-SEM image (field emission scanning electron microscope image) of the cross section thereof, and performing image analysis. More specifically, the FE-SEM image can be measured by determining that the particles are curved particles in which the ratio of the linear distance between both ends of the cross section of the metal particle to the path length between both ends along the cross section of the metal particle is 0.8 times or less, and determining the number ratio. More specifically, the measurement can be performed by, for example, the method described in 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 to be used, using the production method of the invention 2 and/or the invention 3, and the like.

In the step of coating with the metal oxide coating (and if necessary, another coating layer), the pretreatment for improving the dispersibility of the raw aluminum paste, the stirring time, the type of the stirring apparatus, the power and degree of stirring (the type and diameter of the stirring blade, the number of revolutions, the presence or absence of external stirring), and the like may be appropriately adjusted to control the conditions.

Further, by pretreating the raw material aluminum paste, the dispersibility of the particles themselves during the reaction is improved, and the stirring for dispersion is sufficiently mild, so that the deformation of the particles due to stirring can be greatly reduced.

2 nd coating layer

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

The 2 nd coat 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 (oxide of titanium oxide, zirconium oxide, 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-containing compound layer can be promoted while the corrosion resistance of the metal particles is improved.

The 2 nd coating layer (in the case of formation) is particularly preferably formed between the metal particles and the oxidized metal coating such as a silicon-containing compound layer. Thus, for example, a layer structure of "metal particle/2 nd coat layer/oxidized metal coat" may be suitably employed. Although not particularly limited, examples of the molybdenum-containing film include molybdenum-containing films disclosed in japanese patent laid-open publication No. 2003-147226, pamphlet of international publication No. 2004/096921, japanese patent No. 5979788, and japanese patent laid-open publication No. 2019-151678. Examples of the phosphoric acid compound coating include a phosphoric acid compound coating disclosed in japanese patent No. 4633239. A preferred example of the molybdenum-containing substance constituting the molybdenum-containing coating film is a mixed coordination type heteropolyanion compound disclosed in Japanese patent laid-open publication No. 2019-151678.

In another modification, the 2 nd coating layer may be formed on the outer side of the metal particle and the oxide metal such as the silicon-containing compound layer. In still another modification, the constituent components (molybdenum-containing compound, phosphoric acid compound, and the like) of the 2 nd coating layer may be contained in the oxidized metal coating such as the silicon-containing compound layer together with the silicon compound and the like.

The mixed coordination type heteropolyanion compound preferably used in the embodiment of forming a 2 nd coating layer (molybdenum-containing coating as a typical example) other than the metal oxide coating of the composite particles contained in the composite metallic pigment composition of the invention of the present application 1 is not particularly limited, and specific examples thereof include the following.

A mixed coordination type heteropolyanion of a mixed coordination type heteropolyanion compound that can be used has a structure in which some of the polyatomic atoms of a heteropolyanion formed from one element are substituted with other elements, and exhibits physical properties different from those of a mixture of the respective heteropolyanions.

When the compound is represented by the formula, a mixed coordination type heteropolyanion is represented by [ X ] _p M _q N _r O _s ] ^t The heteropolyanion becomes [ X ] _p M _q O _s ] ^t And further with heteropolyanions [ M _q O _s ] ^t And (4) distinguishing. Wherein X As a hetero atom represents an element of group IIIB, IVB or VB such As B, si, ge, P or As, and among them, B, si or P is preferable. The polyatomic groups M and N represent transition metals such as Ti, zr, V, nb, ta, mo, and W, and preferably are Ti, zr, V, nb, mo, and W.

In addition, p, q, r and s represent the number of atoms, and t represents the oxidation number.

Since heteropolyanion compounds have many structures, mixed-coordination type heteropolyanion compounds can have further many structures, but as representative and preferable mixed-coordination type heteropolyanion compounds, the following mixed-coordination type heteropoly acids can be exemplified: h ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstomolybdic acid. N hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadomolybdic acid. N hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ O (silicotungstomolybdic acid n hydrate), H _4+x SiV _x Mo _12-x O ₄₀ ·nH ₂ O (silicovanadomolybdate 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 heteropolyanion compounds, preferred specific example is 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 heteropolyanion compound may be used as an acid (so-called mixed coordination type heteropoly acid) or as a (partial or complete) salt having 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 having 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, aluminum, and the like; inorganic components such as ammonia; and an amine compound as an organic component. Among the inorganic components, salts of alkali metals, alkaline earth metals, and ammonia are preferable.

When at least one member selected from the group consisting of alkali metals, alkaline earth metals and ammonia is used as a counter cation source, it is more preferable to use a counter cation source selected from the group consisting of H ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstomolybdate. N hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadomolybdic acid. N hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ O (silicotungstomolybdic acid n hydrate), H _4+x SiV _x Mo _12-x O ₄₀ ·nH ₂ At least one salt of O (silicovanadomolybdate 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 an amine compound represented by the following general formula (5) is preferred as a specific example.

(R ⁸ -N(-R ¹⁰ )-) _n -R ⁹ (5)

(in the formula, R ⁸ 、R ⁹ And R ¹⁰ The same or different, hydrogen atom, or C1-30 hydrocarbon group of 1 or 2 valence optionally containing ether bond, ester bond, hydroxyl group, carbonyl group, or mercapto group, R may optionally be substituted ⁸ And R ⁹ Together form a 5-or 6-membered cycloalkyl group, or form a 5-or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a crosslinking group, or R may optionally be ⁸ 、R ⁹ And R ¹⁰ Together form a polycyclic multiple ring which may contain more than 1 additional nitrogen and/or oxygen atom as crosslinking group. R ⁸ 、R ⁹ And R 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, secondary, or tertiary amines having a linear or branched alkyl group, tertiary amines having a mixed hydrocarbon group, alicyclic primary amines, primary amines having an aromatic ring substituent, alicyclic secondary amines, secondary amines having an aromatic ring substituent, asymmetric secondary amines, alicyclic tertiary amines, tertiary amines having an aromatic ring substituent, amines having an ether bond, alkanolamines, diamines, cyclic amines, aromatic amines, and the like, or any mixture thereof.

Among these amine compounds, preferable specific examples include at least one selected from primary, secondary, tertiary, and alkanolamine compounds having a linear or branched alkyl group of 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 tri (tridecyl) amine, tristearylamine, N-dimethylethanolamine, N-methyldiethanolamine, triethanolamine, and morpholine.

More preferably, at least one amine compound selected from the amine compounds represented by the general formula (5) and at least one amine compound selected from H ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstomolybdic acid. N hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadomolybdic acid. N hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ O (silicotungstomolybdic acid n hydrate), H _4+x SiV _x Mo _12-x O ₄₀ ·nH ₂ At least one salt of O (silicovanadomolybdate n-hydrate) is used.

Among the mixed coordination type heteropolyanion compounds, H is most preferred ₃ PW _x Mo _12-x O ₄₀ ·nH ₂ O (phosphotungstomolybdic acid. N hydrate), H _3+x PV _x Mo _12-x O ₄₀ ·nH ₂ O (phosphovanadomolybdic acid.n hydrate), H ₄ SiW _x Mo _12-x O ₄₀ ·nH ₂ A heteropoly acid of O (silicotungstomolybdic acid n hydrate) in mixed coordination, or an organic amine salt of the heteropoly acid in mixed coordination.

The 2 nd coating layer other than the oxidized metal coating 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 in a range not to inhibit the desired effect of the invention 1 of the present application. Examples of such a corrosion inhibitor include acid phosphate, dimer acid, organic phosphorus compounds, and metal salts of molybdic acid.

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

In addition, the metal oxide coating and/or the 2 nd coating layer of the composite particle, or other layers, may contain at least one selected from the group consisting of inorganic phosphoric acids and salts thereof, and acid organic (phosphite) esters and salts thereof, from the viewpoint of storage stability.

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

Composite metallic pigment composition

The composite metallic pigment composition of the invention 1 of the present application comprises: the composite particle comprising a metal particle and 1 or more layers of metal oxide coating on the surface thereof, wherein the composite particle satisfies the above-mentioned conditions (1) to (3), and the composite metallic pigment composition satisfies the above-mentioned conditions (4) to (6), and does not impose any other conditions, but may contain, in addition to the composite particle, an unreacted organosilicon compound, a compound forming the 2 nd coating layer, an oligomer or a polymer derived therefrom, and the like as a residual part of a solid component (nonvolatile component), and may contain a solvent such as water used in the production process in addition to a specific amount of a specific solvent associated with the above-mentioned condition (5).

In the composite metallic pigment composition, a silicon compound may be present as a hydrolysate and/or a condensate thereof 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).

In the composite metallic pigment composition, a compound that forms an arbitrarily selected 2 nd coating layer (a molybdenum-containing compound, for example, a mixed coordination type heteropolyanion compound, in an arbitrarily selected mode for forming a molybdenum-containing coating as the 2 nd coating layer) can be present.

In the composite metal pigment composition, an organic oligomer or polymer can be present in any selection.

In the composite metallic pigment composition, at least one selected from the group consisting of an inorganic phosphoric acid and a salt thereof, and an acid-type organic (phosphite) ester and a salt thereof may be present.

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

The composite metallic pigment composition may contain any other component than those described above. 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, light stabilizers used as the above-mentioned antioxidants can be used, and light stabilizers typified by benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylate compounds, oxalic acid derivatives, hindered amine compounds (HALS), and hindered phenol compounds can 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 octylphenyl ether and polyoxyethylene nonylphenyl ether, polyoxyalkylene alkylamino ethers such as polyoxyethylene lauryl amino ether and polyoxyethylene stearyl amino ether, sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate and sorbitan monooleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monooleate; 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 glycerin fatty acid esters such as lauric acid monoglyceride, stearic acid monoglyceride, and oleic acid monoglyceride, and examples thereof include sulfuric acid ester salts such as polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene octylphenyl ether sodium sulfate, polyoxyethylene nonylphenyl ether sodium sulfate, lauryl sulfate triethanolamine, sodium lauryl sulfate, potassium lauryl sulfate, and ammonium lauryl sulfate; sulfonates such as sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate and sodium dialkylsulfosuccinate; examples of anionic surfactants represented by phosphate salts such as potassium alkylphosphate 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 them can be used. Among them, as a particularly preferable example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, or a mixture thereof can be exemplified.

Method for producing composite metal pigment composition

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

The production method of the invention 2 and the production method of the invention 3 are not limited to the production of the composite metallic pigment composition of the invention 1, and can be suitably used for the production of various composite metallic pigment compositions.

The production method of the invention 2 of the present application is a production method of 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 having compatibility with each other and having a boiling point difference of 10 ℃ or more,

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

The production method of the invention 3 of the present application is a production method of 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,

3) A step of washing, filtering and volatilizing the solvent from the composite particles having the metal particles and the metal oxide coating formed on the surfaces thereof obtained in the step 2),

the solvent volatilization in step 3) is carried out in 3 stages or more.

That is, the manufacturing method of the invention 2 of the present application and the manufacturing method of the invention 3 of the present application each have:

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

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

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

In the invention 2 of the present application, the solvent is a mixed solvent of 2 or more solvents having compatibility with each other and having a boiling point difference of 10 ℃ or more, and the solvent volatilization in the step 3) is performed in a state of a slurry containing the composite particles and the solvent, but the invention 3 of the present application is not limited thereto, and in this respect, the invention 2 of the present application is different from the invention 3 of the present application, and in the invention 3 of the present application, the solvent volatilization in the step 3) is performed in 3 stages or more, while the invention 2 of the present application is not limited thereto, and in this respect, the invention 2 of the present application is different from the invention 3 of the present application.

These steps will be described below.

1) Process for dispersing metal particles in solvent

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

The method for 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 ultrasonic waves, or the like is preferably employed.

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

The stirring can be carried out by a known or commercially available stirring apparatus. For example, at least one of a kneader, a rotary vessel mixer, an agitation type reaction vessel, a V-type mixer, a twin cone mixer, a screw mixer, a crank mixer, a flash mixer, a jet mixer, a ball mill, an edge runner mill, and the like can be used.

Among these mixers, a device for performing mixing by a mixing blade (impeller) is preferably used. The stirring blade exerts a circulating action of flowing the entire system including the metal particles and the solvent and also exerts a pressure shearing action, and as a result, the metal particles are dispersed more efficiently while being inhibited from aggregating.

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

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

The linear velocity of stirring (the tip velocity of the stirring blade) is preferably 0.5 to 30m/s, more preferably 1 to 20m/s. When the linear velocity of stirring is in the range of 0.5 to 30m/s, the dispersibility of the metal particles can be improved, and a composite metallic pigment composition which is small in the aggregation of the respective particles, excellent in design, gloss and coating film appearance and little in gas generation can be obtained more easily. When the linear velocity of stirring is in the above range, the aggregation of particles can be effectively suppressed while preventing breakage of metal particles (for example, scale-like aluminum powder).

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

As the pretreatment, for example, when the metal particles to be the raw material are dispersed in an inert solvent and supplied, the solvent may be replaced with the same solvent as the solvent used in the covering treatment. Further, if necessary, the solvent is sufficiently compatible with the surface of the metal particles by heating for a certain period of time, whereby the aggregation generated in the step 2) of coating the metal particles with the metal oxide can be significantly suppressed. The heat treatment temperature is preferably about 30 to 60 ℃, and the treatment time is preferably optimized to 3 hours to 7 days. In the step of performing the covering treatment, a hydrophilic solvent such as ethanol, isopropanol, or methoxypropanol is preferably used, and therefore, the same hydrophilic solvent as that used in the reaction is preferably used in the pretreatment.

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

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

2) Process for covering metal particles with oxidized metal

The metal oxide coating can be formed on the metal particles by performing 2) the step of 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 step of forming a silicon-containing compound layer will be described below by taking an embodiment in which at least 1 layer of the metal oxide coating is a silicon-containing compound layer as an example, as a specific example of step 2).

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 organosilicon compounds, a solvent, and, if necessary, other optional components.

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

As the metal particles, the above-described metal particles can be used, but particles of aluminum or an aluminum alloy can be particularly suitably used. In addition, as for the particle shape, as described above, it is preferable to use metal particles in a flake form. 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 liquid is not particularly limited, and may be appropriately set according to the kind, particle size, and the like of the metal particles to be used.

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

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

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

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 of mixing both (referred to as "method 1") can be employed. Alternatively, a method including steps of forming a 1 st silicon-containing compound layer by performing one treatment and forming a 2 nd silicon-containing compound layer by performing the other treatment on the metal particles (referred to as a "2 nd method") may be employed.

Examples of the method 1 include: and a method for forming a silicon-containing compound layer, which comprises a step of forming a silicon-containing compound layer by subjecting a tetraalkoxysilane and a silane coupling agent to a hydrolysis/condensation reaction by appropriately adjusting the pH of a mixed solution containing metal particles, the tetraalkoxysilane represented by the above formula (1), and the silane coupling agent represented by any one of the above formulae (2) to (4).

Examples of the method 2 include: a step of forming a 1 st silicon-containing compound layer (for example, 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 tetraalkoxysilane represented by the above 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 the metal particles and the silane coupling agent represented by any one of the above formulae (2) to (4) to cause a hydrolysis/condensation reaction of the silane coupling agent.

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

The amount of the silane coupling agent represented by any one of the above formulae (2) to (4) is not particularly limited, and may be usually 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 components). When the amount is about 0.1 to 20 parts by mass, a desired effect of the coating treatment and preferable physical properties of the coating film 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 to be used, and water, a hydrophilic organic solvent, or a mixed solvent thereof may be usually used. By using these solvents, the uniformity of the reaction, the uniformity of the resulting hydrolysate and/or condensation reactant may be improved. In the aspect of forming the silicon-containing compound layer directly 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 a rapid reaction between the metal particles and water. In the present 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 and esters thereof 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, etc.; glycols of ethylene glycol, propylene glycol, 1, 3-butylene glycol, 1, 4-butylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, and ethylenepropyleneglycol; ethyl cellosolve, butyl cellosolve, acetone, methoxypropanol, ethoxypropanol, other alkoxy alcohols, and the like. These may be used in 1 or 2 or more.

The amount of the solvent used in the step of forming the silicon-containing compound layer (when the metal particles are dispersed in advance, the amount of the solvent used therefor is not limited), and may be generally about 100 to 10000 parts by mass, and particularly preferably 200 to 2000 parts by mass, per 100 parts by mass of the metal particles (solid content). When the amount of the solvent is 100 parts by mass or more, the viscosity of the mixed solution (slurry) is suppressed from increasing, and the mixed solution can be appropriately stirred. Further, 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. The amount of the solvent used herein means the total amount of the solvents used for the formation of the 1 st silicon-containing compound layer and the formation of the 2 nd silicon-containing compound layer in the case of the above 2 nd method.

The mixed solution may contain other additives as necessary within a range not to inhibit the effects of the invention 1 of the present application. For example, in addition to catalysts such as hydrolysis catalysts and dehydration condensation catalysts, surfactants, metal corrosion inhibitors, and the like can be cited.

Among them, a hydrolysis catalyst can be suitably used. By adding the hydrolysis catalyst, the pH of the mixed liquid can be adjusted and the organosilicon compound can be efficiently hydrolyzed and subjected to dehydration condensation, and as a result, a silicon-containing compound 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. Examples of the hydrolysis catalyst include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; organic acids such as benzoic acid, acetic acid, chloroacetic acid, salicylic acid, oxalic acid, picric acid, phthalic acid, and malonic acid; phosphonic acids such as vinylphosphonic acid, 2-carboxyethanephosphonic acid, 2-aminoethanephosphonic acid, and octanesulfonic acid. These hydrolysis catalysts may be used alone in 1 kind or in combination of 2 or more kinds.

As the hydrolysis catalyst, for example, inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide; inorganic alkali salts such as ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate; amines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, N-dimethylethanolamine, ethylenediamine, pyridine, aniline, choline, tetramethylammonium hydroxide, and guanidine; ammonium formate, ammonium acetate, monomethylamine formate, dimethylamine acetate, pyridine lactate, guanidinoacetic acid, aniline acetate, and the like. These hydrolysis catalysts may be used in 1 kind or 2 or more kinds.

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

The composite metallic pigment composition according to claim 1 of the present application is preferably produced by stirring the above-mentioned mixed liquid with an appropriate intensity.

The temperature of the mixed solution may be either normal temperature or heated. The temperature of the mixed solution is usually 20 to 90 ℃ and is preferably controlled to 30 to 80 ℃. When the temperature is 20 ℃ or higher, the formation rate of the silicon-containing compound layer increases, and the treatment time can be shortened. 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 used for stirring the mixed liquid is not particularly limited, and a known stirrer capable of uniformly stirring the mixed liquid containing the aluminum particles and the organosilicon compound efficiently can be used. Specific examples thereof include a kneader, a rotary vessel mixer, a stirred tank reactor, a V-type mixer, a twin cone mixer, a screw mixer, a sigma mixer, a flash mixer, a jet mixer, a ball mill, and a wheel mill.

The temperature of the mixed liquid when the mixed liquid containing the metal particles and the organosilicon compound is stirred may be generally about 10 to 100 ℃, and particularly preferably 30 to 80 ℃. When the temperature is 10 ℃ or higher, the reaction time for obtaining a sufficient treatment effect can be shortened. Further, when the temperature is 100 ℃ or lower, the control of the reaction for obtaining a desired composite metallic pigment composition becomes easier.

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

In the mixed liquid, a silicon-containing compound layer is formed on the surface of the metal particle (or via the 2 nd coating layer) by subjecting the silicon-containing raw material to hydrolysis/condensation reaction. The hydrolysis/condensation reaction can be carried out by, for example, adjusting the pH of the mixed solution.

In the case of adjusting the pH, particularly in the stage where the silicon-containing compound layer is formed on the surface of the metal particle (or via the 2 nd coating layer), the pH of the mixed solution changes, and therefore it is preferable to appropriately adjust the pH 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 the pH may be adjusted by using other acidic or basic compounds as long as the characteristics of the composite metallic pigment composition of the invention 1 of the present application are not impaired.

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

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

In both of the above-mentioned methods 1 and 2, the hydrolysate and/or the condensate of the organosilicon compound represented by the above general formula (1) 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 in which the hydrolysis and condensation reaction is completed, based on 100 parts by mass of the metal particles (solid component). The hydrolysate and/or condensate thereof 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 a total 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, based on 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 in which the organosilicon compound is completely hydrolyzed and condensed.

For example, when Tetraethoxysilane (TEOS) is used as the organosilicon compound represented by the general formula (1), the amount of the hydrolysate and/or condensate of the organosilicon compound to be added can be calculated from 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 before and after the above hydrolysis and condensation reaction is 60/208=0.288 times, when 10 parts by mass of TEOS is used per 100 parts by mass of 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 thereof.

Similarly, the amount of the hydrolysate and/or condensate of the silane coupling agent or the like represented by any one of the general formulae (2) to (4) to be added can also be calculated by multiplying the mass of the silane coupling agent and/or the partial condensate thereof represented by any one of the general formulae (2) to (4) used in producing the composite metallic pigment composition by the mass ratio before and after the reaction in which the silane coupling agent and/or the 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 amount of the hydrolysate and/or condensate of the silane coupling agent can be calculated using the mass ratio before and after the hydrolysis and condensation reaction described below.

(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 before and after the hydrolysis/condensation reaction is 67/136=0.49 times, for example, when methyltrimethoxysilane is used in an amount of 1.23 parts by mass based on 100 parts by mass of the metal particles (solid components), the amount of the hydrolysate and/or the condensate thereof is 0.49 times, that is, 0.60 parts by mass based on the hydrolysate.

3) Washing, filtering and dissolving the composite particlesStep of volatilizing agent

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

In the production of the composite metallic pigment composition according to the invention 1 of the present application, the step 3) is not essential, but is preferably carried out.

In the process for producing a composite metallic pigment composition according to the invention of claim 2 of the present application, the step 3) is carried out, and the solvent in this case is a mixed solvent of 2 or more solvents having compatibility with each other and having a boiling point difference of 10 ℃ or more, and the solvent volatilization in the step 3) is carried out 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 3 rd aspect of the present invention, the step 3) is performed, and the solvent volatilization 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, and for example, the slurry or cake containing the composite particles obtained in step 2) may be washed with an organic solvent. By washing, water, unreacted materials, solvents which are not preferable in the final composite metallic pigment composition, and the like can be removed from the slurry, presscake, 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, and the like at the time of washing in step 3) are not particularly limited, and the washing may be carried out at 10 to 70 ℃ and preferably 15 to 60 ℃ for 5 to 180 minutes, and preferably 10 to 120 minutes.

In washing, an organic solvent is preferably used, and from the viewpoint of removal of moisture, convenience in using the composite metallic pigment composition in a water-based 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 this organic solvent further easily satisfies the condition that (5) in the invention 1 of the present application is hydrophilic and the solvent having a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid content of the composite metallic pigment composition. Preferable examples of the hydrophilic solvent having a boiling point of 80 to 150 ℃ include methoxypropanol, isopropanol, isobutanol, n-butanol, and n-propanol.

The number 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. Further, it is also one of preferable examples that washing is carried out by continuously or intermittently circulating a washing liquid through a suction filter type filter.

The filtration in step 3) can be carried out by a method commonly used in the art. For example, a general air permeability of 10 to 100 ml/cm can be used ² Per minute, preferably a permeability of 20 to 80 ml/cm ² Filter cloth made of polypropylene per minute, metal filter having the same pore size, glass filter, ceramic filter, etc. filtration was performed by suction filtration and pressure filtration using a suction filter type filter, and a method such as a filter press, belt press, centrifugal filter, etc. was appropriately used. By performing filtration, water, unreacted materials, solvents which are not preferable in the final composite metallic pigment composition, and the like can be removed from the composite particles obtained in step 2).

The temperature and pressure of the filtration in the step 3) are not particularly limited, and when a suction filter type filter is generally used, the filtration can be carried out at 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 amount of solid components in 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.

From the viewpoint of low VOC and the like, the amount of solid components such as slurry and cake containing composite particles after filtration is preferably high, and therefore the pressure during filtration can be set high, but the high pressure during filtration may cause aggregation and deformation of the composite particles, and therefore the pressure is preferably set in consideration of this.

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

The number of filtration is not particularly limited, and filtration may be performed only 1 time, or washing and filtration may be alternately performed a plurality of times. By alternately performing washing and filtration a plurality of times, water, unreacted materials, solvents which are not preferable in the final composite metal pigment composition, and the like are further efficiently removed, and it is further easy to satisfy the condition that (5) in the invention of claim 1 of the present application is hydrophilic and the solvent having a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid components of the composite metal pigment composition.

In the filtration, it is preferable to evaporate the solvent by passing a gas through the slurry, the surface of the cake, and the void portion at the same time. As a result, a composite metal pigment composition having a high solid content, in which a solvent having a low boiling point preferentially volatilizes and a solvent having a high boiling point mainly remains, can be easily obtained.

The solvent volatilization in the step 3) can be carried out by a method generally used in the art. For example, solvent evaporation can be carried out by heating, reduced pressure, aeration, a combination thereof, or the like.

Since the ratio of the solid content is improved by removing the volatile matter by volatilization of the solvent, a composite metallic pigment composition satisfying the condition that the solid content concentration of the composite metallic pigment composition (4) in the invention 1 of the present application is 70 to 95 mass% can be efficiently produced. Further, since the solvent or the like which is not preferable in the composite metallic pigment composition can be removed by volatilization of the solvent, it is possible to further easily produce a composite metallic 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 components of the composite metallic pigment composition.

The temperature, pressure, time, and the like for solvent volatilization in the step 3) are not particularly limited, and the solvent volatilization can be usually carried out at a temperature of 15 to 100 ℃, preferably 20 to 80 ℃, more preferably 30 to 70 ℃, and at a pressure of 0.1 (normal pressure) to 0.001MPa, preferably 0.05 to 0.01MPa in terms of absolute pressure while confirming the degree of solvent volatilization.

When the solvent is volatilized by ventilation, it is preferable to use dry air, and the dew point and the ventilation flow rate can be appropriately adjusted while confirming the volatilization degree of the solvent.

The composite metal pigment composition can be obtained directly by volatilization of the solvent, or can be obtained through a further step. The amount of the solid component in the composite metallic 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 process for producing a composite metallic pigment composition according to claim 2 of the present application, the solvent in the step 3) is a mixed solvent of 2 or more solvents having compatibility with each other and having a boiling point difference of 10 ℃ or more. The solvent used in the respective steps before that is replaced with a mixed solvent in which 2 or more solvents having a boiling point difference of 10 ℃ or more, that is, a mixed solvent in which low-boiling point solvents are mixed, which have compatibility with each other, are used, and the low-boiling point solvent is selectively volatilized, whereby a solvent to be left, for example, a solvent having hydrophilicity and a boiling point of 80 to 150 ℃ can be selectively left. Further, since the low boiling point solvent is relatively easily volatilized, and an extreme pressure reduction such as a high temperature is not required, the solid content concentration can be relatively easily improved while suppressing deformation and aggregation of the composite particles.

The difference in boiling points between the 2 or more solvents constituting the mixed solvent is preferably 10 to 80 ℃ and 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, ethanol, and the like can be preferably used.

In particular, it is preferable to use a combination of methoxypropanol, which is a solvent on the high boiling point side, and isopropanol, which is a solvent on the low boiling point side.

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

In step 3), the solvent volatilization is performed in a state of a slurry containing the composite particles and the solvent in a mixed solvent of 2 or more solvents having compatibility with each other and having a boiling point difference of 10 ℃ or more, whereby the solvent on the low boiling point side is volatilized and the solvent on the high boiling point side is more easily left in the composite metallic pigment composition.

In the method for producing a composite metallic pigment composition according to claim 3 of the present application, the solvent volatilization in the step 3) is performed in 3 stages or more. In this case, the solvent volatilization divided into 3 stages or more may be continuously performed, but it is preferable to perform a step of making the whole solvent component contained in the slurry uniform, for example, a step of stirring, aging, or the like, between the solvent volatilization in 1 stage and the solvent volatilization in the subsequent stage. In the step of homogenizing the solvent component, a solvent may be newly added to partially replace the solvent.

By carrying out the solvent volatilization in 3 stages or more, and preferably by alternately carrying out volatilization and dispersion, it is possible to suppress formation of a portion having a small solvent locally, to effectively prevent aggregation and deformation of the composite particles, and to relatively easily and efficiently produce a composite metallic pigment composition having a high solid content and a preferable solvent composition, such as the composite metallic pigment composition of the invention 1 of the present application.

In the method for producing a composite metallic pigment composition according to the invention 2 and the invention 3, a solvent having a low water content is preferably used from the viewpoint of suppressing aggregation of the composite particles. In particular, it is preferable that the water content of the solvent is low when the solvent is volatilized in the step 3). 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.

Since the moisture content of the entire system of the composite metallic pigment composition obtained in this case may be preferably 0.1% by mass or less, more preferably 0.05% by mass or less, it is further easy to reduce the amount of residue to preferably 0.1% by mass or less, more preferably 0.003% by mass or less of the solid content.

Other steps

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

Crushing, screening, filtering, etc. of metal particles

The metal particles may be pulverized, sieved, and/or filtered before the step of 1) dispersing the metal particles in the solvent. The metal particles are pulverized, sieved, and/or filtered to make the particle diameter of the metal particles more uniform and fine, and therefore, the metal particles are preferable from the viewpoint of producing 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 described as an example.

The aluminum powder is usually obtained by pulverizing atomized aluminum powder and/or aluminum foil in the presence of a pulverization aid and 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, a pounder method, etc., to form a so-called scale, and then subjecting the resultant powder to necessary steps, such as sieving (classification), filtration, washing, and mixing, after the step.

Examples of the grinding aid herein include fatty acids, fatty amines, fatty amides, and fatty alcohols. Oleic acid, stearic acid, stearylamine and the like are generally preferred. Examples of the inert solvent include mineral spirits, solvent naphtha, toluene, xylene, and other inert solvents exhibiting hydrophobicity, and these solvents can be used alone or in combination. The pulverization aid and the inactive solvent are not limited to them.

In the grinding step, from the viewpoint of preventing dust explosion and ensuring safety, grinding by a wet ball mill method is preferable.

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

Step 2 of Forming capping layer

The composite particle constituting the composite metallic pigment composition of the invention of the present application 1 preferably has a covering layer (2 nd covering layer) other than the oxidized metal covering, preferably a covering 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 covering. The 2 nd coating layer (in the case of formation) is particularly preferably formed between the metal particles and the oxidized metal coating such as a silicon-containing compound layer. Therefore, a layer structure of "metal particle/2 nd coat layer/oxidized metal coat" may be suitably employed.

The 2 nd coating layer is not particularly limited, and may be a molybdenum-containing coating, a phosphoric acid compound coating, or the like. A preferred example of the molybdenum-containing substance constituting the molybdenum-containing coating film is a mixed coordination type heteropolyanion compound disclosed in Japanese patent laid-open publication 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 oxide metal coating such as a silicon-containing compound layer.

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

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

The stirrer for stirring the mixed liquid containing the metal particles and the molybdenum compound is not particularly limited, and a known stirrer capable of efficiently and uniformly stirring the mixed liquid containing the metal particles and the molybdenum compound may be used. Specific examples thereof include a kneader, a rotary vessel mixer, a stirred tank reactor, a V-type mixer, a twin cone mixer, a screw mixer, a sigma mixer, a flash mixer, a jet mixer, a ball mill, and a wheel mill. Examples of the stirring blade of the stirrer are not particularly limited, and anchor blades, propeller blades, turbine blades, and the like can be mentioned.

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

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

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

The amount of the solvent used in the step of forming the 2 nd coating layer (when the metal particles are dispersed in advance, the amount of the solvent used is not particularly limited), and is usually 50 to 5000 parts by mass, more preferably 100 to 2000 parts by mass, based on 100 parts by mass of the metal particles (solid content). The use amount of the solvent is 50 parts by mass or more, whereby segregation of the molybdenum compound and aggregation of the metal particles can be suppressed. In addition, when the amount of the solvent used is 5000 parts by mass or less, a sufficient treatment effect with respect to the metal particles by the molybdenum compound can be obtained.

The temperature of the mixed liquid when the mixed liquid containing the metal particles and the molybdenum compound is stirred may be generally about 10 to 100 ℃, and particularly preferably 30 to 80 ℃. When the temperature is 10 ℃ or higher, the reaction time for obtaining a sufficient treatment effect can be shortened. Further, when the temperature is 100 ℃ or lower, the control of the reaction for obtaining a desired composite metallic pigment composition becomes easier.

The stirring time of the mixed solution is not particularly limited as long as it is 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. When the stirring time is 0.5 hour or more, a sufficient treatment effect can be obtained. Further, when the stirring time is 10 hours or less, an increase in the treatment cost can be suppressed.

After the completion of the stirring of the mixed liquid containing the metal particles and the molybdenum compound, the particles having the 2 nd coating layer formed thereon can be recovered. In this case, known washing, solid-liquid separation, and the like may be appropriately performed as necessary. For example, it is preferable to remove water and unreacted materials 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 solution with a filter or the like. In this manner, a molybdenum-containing coating film as the 2 nd coating layer can be formed. In the case of forming another 2 nd cover layer, the above method may be used.

In the embodiment of forming the 2 nd coating layer (hereinafter, a molybdenum-containing coating layer will be described as an example) on the metal particles and then forming the metal oxide coating layer (hereinafter, a silicon-containing compound layer will be described as an example), a dispersion of water and/or a hydrophilic organic solvent of a silicon compound source (typically, at least one of the organosilicon compound represented by the above formula (1), for example, tetraalkoxysilane and/or a condensate thereof, and the silane coupling agent represented by any one of the above formulae (2) to (4)) may be directly added to and stirred in the system after completion of stirring of the mixed solution containing the metal particles and the molybdenum compound, without recovering the particles on which the 2 nd coating layer is formed. In this case, a dispersion of the organosilicon compound represented by the above formula (1), for example, tetraalkoxysilane and/or a condensate thereof, may be added to a system containing the particles having the 2 nd coating layer formed thereon, and then a dispersion of at least one of the silane coupling agents represented by any one of the above formulae (2) to (4) may be added/stirred.

Use of composite metallic pigment compositions

The composite metallic pigment composition according to claim 1 of the present application and the composite metallic pigment composition produced by the production method according to claim 2 and/or 3 of the present application can be used for organic solvent-based paints, inks, and the like. The composite metallic pigment composition can be added to an aqueous coating material 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 form a metallic aqueous coating material or a metallic aqueous ink. The composite metallic pigment composition may be used as a binder or filler for water resistance by kneading with a resin or the like. The antioxidant, light stabilizer, and surfactant may be added when the composite metallic pigment composition is blended with an aqueous coating material, an aqueous ink, or a resin.

When the composite metallic pigment composition is used for a coating material or an ink, it may be added as it is to a (water-based) coating material or a (water-based) ink, but it is preferably added after it is dispersed in a solvent in advance. Examples of the solvent used include water, lauryl alcohol ester, diethylene glycol monobutyl ether, and propylene glycol monomethyl ether. Examples of the resins include acrylic resins, polyester resins, polyether resins, epoxy resins, fluorine resins, and rosin resins. Examples of binders for paints and inks include resins and rubbers.

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

Preferable resins include acrylic resins and polyester resins.

Resins such as melamine-based curing agents, isocyanate-based curing agents, and urethane dispersions may be used in combination as needed. Further, it may be combined with a coloring pigment such as an inorganic pigment, an organic pigment, or an extender pigment, a silane coupling agent, a titanium coupling agent, a dispersant, a sedimentation preventing agent, a leveling agent, a thickener, or an antifoaming agent, which are generally added to a paint. In order to improve the dispersibility in the coating material, a surfactant may be further added. In order to improve the storage stability of the coating material, 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, pearl mica, and the like.

The content of the composite metallic pigment composition according to the invention 1 of the present application or the composite metallic pigment composition produced by the production method according to the invention 2 or 3 of the present application in the above-mentioned aqueous coating material or 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% by mass or more, a high decorative (metallic) effect can be obtained. In addition, when the content is 30% by mass or less, the properties of the aqueous coating material or the aqueous ink, for example, weather resistance, corrosion resistance, mechanical strength, and the like can be prevented from being impaired.

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

The coating method or printing method of the water-based paint or 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 coating material 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 method, and a blade coating method. Examples of the printing method include gravure printing and screen printing.

A coating film formed by an aqueous coating material or the like may be formed on the undercoat layer or the intermediate layer formed by electrodeposition coating or the like. Further, a surface coating layer or the like may be formed on the coating film formed by the aqueous coating material or the like as necessary.

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

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

The thickness of the coating layer formed by the aqueous coating material or the like is not particularly limited, but is usually preferably about 0.5 to 100 μm, more preferably about 1 to 50 μm. The hiding effect of the substrate by the ink or paint is sufficiently obtained by the thickness of the coating film layer being 0.5 μm or more. Further, when the thickness of the coating layer is 100 μm or less, drying becomes easy, and generation of defects such as wrinkles and sagging can be suppressed.

The composite metallic pigment composition according to the invention of claim 1, the composite metallic pigment composition obtained by the production method according to the invention of claim 2 or 3, and the coating film obtained using the same have excellent design properties, gloss, suppression of particle formation, stability in an aqueous coating material, and the like at a high level, and thus can be suitably used for various applications in which metallic pigments have been used, such as a coating material, an ink, a resin kneading agent, and the like, more specifically, an automobile body, an automobile repair material, an automobile part, a home appliance, and the like, a plastic part, a coating material for PCM, a highly weather-resistant coating material, a heat-resistant coating material, an anticorrosive coating material, a coating material for a ship bottom, an offset printing ink, a gravure printing ink, a screen printing ink, and the like.

Examples

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

Example 1

1m of diameter 2m of anchor type stirring blade with blade diameter 1m ² To a reaction vessel of (1), 465kg of methoxypropanol (hereinafter, referred to as "PM") was added to 135kg of a commercially available aluminum paste (trade name "GX-3100 (mean particle diameter: 11 μm, nonvolatile content: 74%)" manufactured by Asahi Kasei corporation), and the mixture was stirred at 100rpm by a stirring blade, and the aluminum paste was uniformly dispersed in the PM while circulating a 10L/min dispersion withdrawn from the bottom from the upper part of the reaction vessel to the outside of the reaction vessel. In the external circulation, 500W of ultrasonic waves were irradiated to the middle of the channel for 1 minute to improve the dispersibility of the particles.

Then, phosphotungstomolybdic acid (H) was slowly added ₃ PW ₆ Mo ₆ O ₄₀ ) Hydrate 1kg was dissolved in methoxypropanol 5kg to obtain a liquid, and the slurry was stirred for 1 hour while maintaining the temperature at 40 ℃. During 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% ammonia water and 200kg of purified water were added over 3 hours. Then, 1.3kg of methyltrimethoxysilane was added as a silane coupling agent, and the mixture was stirred for 2 hours. During the reaction, the external circulation was continued while ultrasonic wave irradiation was performed. After the reaction is finished, the slurry is pressurized and filtered after being cooled.

The filtered slurry was treated with isopropyl alcohol (hereinafter referred to as "IPA")/PM: the 3/2 mixture solution was sufficiently washed to replace the solvent, and then pressure-filtered again to evaporate mainly IPA with ventilation, thereby obtaining a composite aluminum pigment composition containing 90% of nonvolatile matter. The water content of the IPA/PM mixed solvent used here was 200ppm, and dry air having a dew point of-40 ℃ was used for pressure filtration and ventilation.

Example 2

A composite aluminum pigment composition having 90% of non-volatile matter was obtained in the same manner as in example 1 except that the aluminum paste was changed to an aluminum paste (product name "GX-4100 (average particle size: 10 μm, non-volatile matter: 74%)" manufactured by Asahi Kasei corporation).

Example 3

A composite aluminum pigment composition having 85% of non-volatile content 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 size 9 μm, non-volatile content 75%)" manufactured by Asahi Kasei corporation).

Example 4

The reaction was carried out in the same manner as in example 1 until completion, and after completion of the reaction, the slurry was cooled and filtered, and washing and filtering were repeated 3 times with an equal amount of PM to obtain a paste having a nonvolatile content of 50%. Subsequently, the solvent was evaporated at room temperature under reduced pressure to increase the nonvolatile content by 10%, and then the mixture was mixed by removing the reduced pressure to make the paste uniform, and the mixture was sealed and left to stand for 12 hours. This operation was further performed 2 times to obtain a composite aluminum pigment composition in the form of a paste having 90% of nonvolatile content.

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 the IPA/PM mixed solvent having a water content of 2000ppm was used as the IPA/PM mixed solvent.

Comparative example 1

To a commercially available aluminum paste (product name "GX-3100 (average particle size 11 μm, nonvolatile content 74%)", manufactured by Asahi chemical Co., ltd.) in an amount of 135kg, 465kg of PM was added and dispersed to obtain a slurry, and the slurry was stirred while slowly adding phosphotungstic molybdic acid(H ₃ PW ₆ Mo ₆ O ₄₀ ) 1kg of hydrate was dissolved in 5kg of PM to prepare a liquid, and the slurry was stirred for 1 hour while maintaining the temperature at 40 ℃. Then, after cooling, the slurry was filtered 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 after filtration after completion of the reaction was changed to a step of transferring the aluminum pigment composition to another vessel, and removing the solvent by heating to 50 ℃ and reducing the pressure in a static state for 1 hour.

Comparative example 3

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

(evaluation of composite Metal pigment composition)

₅₀ Average particle size: d

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

As a measurement solvent, isopropyl alcohol was used.

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

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

Concentration of solid component

The mass of the composite aluminum pigment composition 10g obtained in each of the above examples/comparative examples was measured after heating at 105 ℃ for 3 hours to volatilize the volatile matter, and the ratio thereof was determined as the mass of the solid matter.

Residue of rice

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

(evaluation of coating Material and coating film)

An aqueous metallic coating material was produced using the composite aluminum pigment compositions obtained in the above examples and comparative examples, and the coating material and the coating film obtained therefrom were evaluated by the following method. The results are shown in table 1.

An aqueous metallic coating having the following composition was produced.

Composite aluminum pigment composition: 12.0g as a nonvolatile matter

Methoxypropanol: 18.0g

Polyoxyethylene lauryl ether (nonionic surfactant, product of Songban oil & fat pharmaceuticals, trade name "Marpon L5"): 6.0g

Purified water: 12.0g

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

Melamine resin (@ 2): 18.0g

The method comprises the steps of (1): almatox WA911 available from Mitsui chemical Co., ltd

In addition, 2: manufactured by Nihon Cytec Industries Inc. of 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 (type B viscometer, no.3Low, 60 rpm, 25 ℃) with a carboxylic acid thickener and purified water.

The following evaluations were carried out using the thus-produced aqueous metallic coating material.

Evaluation 1 (storage stability (gas generation))

200g of the aqueous metallic paint prepared according to the above formulation was collected in a flask, and the cumulative amount of hydrogen generation was measured in a constant temperature water bath at 60 ℃ for 24 hours. The amount of gas generated was evaluated as an index of storage stability in the paint, based on the following criteria.

O: less than 2ml

And (delta): 2ml or more and less than 10ml

X: 10ml or more and less than 50ml

X: more than 50ml

Evaluation 2 (film coating evaluation)

The water-based metallic paint prepared according to the above formulation was air-spray coated to a 12cm × 6cm steel plate (manufactured by Miki coating k.k.) for forming a middle coat coating so as to have a dry film thickness of 6 μm, predried at 90 ℃ for 10 minutes, then the paint for organic solvent-based top coating having the following composition was dispersed by a spatula for 3 minutes, the paint viscosity was adjusted to 20.0 seconds by ford cup No4 so as to form a dry film thickness of 20 μm, and the paint plate was dried at 140 ℃ for 30 minutes to prepare a coated plate for the following evaluation.

(composition of coating for organic solvent-based surface coating)

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

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

123.5g of toluene

2-i (film coating and granulation)

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 criteria.

Good: no visible particles

And (delta): the number of the particles is less than 10

X: more than 10 particles

2-ii (Brightness)

For the resulting coated panels, evaluations were performed using a laser-based metal sensing device, alcope (1245012523671254012503). As optical conditions, a laser light source having an incident angle of 45 degrees and light receivers at acceptance angles of 0 degrees and-35 degrees. As the measured value, the IV value was obtained at-35 degrees, which is the acceptance angle at which the maximum light intensity was obtained, except for the light in the specular reflection region reflected on the surface of the coating film among the reflected light of the laser beam. The IV value is a parameter proportional to the intensity of the regular reflection light from the coating film, and indicates the magnitude of the lightness.

The obtained IV value was evaluated based on the following criteria.

Good: the reduction from the reference (comparative example 1) was less than 20.

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

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

2-iii (concealment)

The produced aqueous metallic coating material was applied to a polyethylene terephthalate sheet (PET sheet) using a 2 mil applicator so as to have a dry film thickness of 15 μm, and the resultant coating film was visually examined for 30 minutes at 140 ℃.

O: the level was reduced to a slight level as in the reference (comparative example 1).

And (delta): lower than the reference (comparative example 1).

X: significantly lower than the standard (comparative example 1).

(evaluation of aggregation and deformation of composite particles)

In order to facilitate the determination of the aggregation state of particles, a coating material was prepared under the same conditions and a coated board was prepared under the conditions of evaluation 2 except that the amount of aluminum paste used for the mixing of the coating material used for the preparation of the coated board in evaluation 2 was 1/10.

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

The cross section of the obtained coating film was set so that ion beam irradiation could be performed to a portion 20 μm away from the cross section of the coating film by using an ion milling apparatus (manufactured by electronics of japan/IB-09010 CP), and a precision polished cross section sample was prepared by ion milling.

The cross section of the obtained coating film (coated sheet) was observed by FE-SEM (HITACHI/S-4700) to observe the state of overlapping of particles and the state of deformation of the particles, and the evaluation was carried out according to the following procedure.

Ratio of 1 Xparticles (aggregation state)

First, it is possible to easily determine the degree of overlapping of particles and observe the particles at a magnification of approximately 1000 to 3000 times. When the degree of overlap cannot be discriminated at this magnification, the degree of overlap is evaluated by appropriately changing the magnification. In this observation method, observation is performed at a magnification of approximately 30000 times at maximum. A plurality of fields of view were observed from the cross section of the same 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 present when the length of the contact portion between the particles is 1/4 or less of the particle diameter of the smaller particles (particles having a short major diameter), and it is determined that aggregation is present when the length is greater than 1/4.

Ratio of curved particles (deformation state)

The degree of deformation of the particles can be easily determined and observed at a magnification of approximately 1000 to 3000 times. When the deformation cannot be discriminated at this magnification, the degree of deformation is evaluated by appropriately changing the magnification. In this observation method, observation is performed at a magnification of approximately 30000 times at maximum. A plurality of fields of view were observed from the cross section of the same sample piece so that the number of particles observed was 500 or more. The presence or absence of the distortion is judged when the shortest distance between both ends of the particle is 0.8 times or less the length of the particle.

Average particle thickness of metal particles

The FE-SEM image (1 ten thousand times) obtained by the above-described obtaining procedure and image analysis software Win roff version 5.5 (manufactured by MITANI CORPORATION) were used to measure the thickness of the particles in the cross section of the aluminum particles and calculate the average thickness.

An FE-SEM image obtained by measuring the thickness of the particles in the cross section of the aluminum particles was displayed, and the ROI line was selected so as to match the ROI line to the 5 μm scale of the image, and set by registering/changing the input length/unit.

Next, an image showing the measurement of the thickness of the cross section of the aluminum particle was obtained, and a rectangular ROI was selected and subjected to 2-value processing so as to match the rectangular ROI with the cross section of the particle.

Subsequently, measurement items of the measured vertical chord length are selected, measurement is performed, and an automatic measurement value (vertical chord length value) obtained by image analysis software is displayed on the image.

In this manner, 300 particles were selected using the image analysis software Win Roof version 5.5, and the thickness and major axis of the cross section of the aluminum particle were automatically measured. Then, an arithmetic mean thickness was calculated for 300 particles to determine the average thickness t of the particles. The aluminum particles have high thickness uniformity, and the difference in thickness due to the cut portions of the particles is small. This makes it possible to ignore the influence of the difference in the cut site of the particle on the measurement of the average particle thickness.

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

The average thickness of the particle coating layer was measured at a magnification of 20 ten thousand times using a STEM (scanning transmission electron microscope) for the coated plate used for obtaining the FE-SEM image. When the surface of the coating layer had irregularities, the area of the coating layer was measured by using image analysis software Win Roof version 5.5, and divided by the perimeter of the particle covering it to obtain the average thickness of the coating layer. When the particle size is large, it is not always necessary to measure the entire area of the coating layer, and the average thickness of the coating layer can be obtained with sufficient accuracy by measuring the area of the coating layer in a region of about 1 μm along the particle surface and dividing the area by the particle surface length. Since the average thickness of the coating layer was substantially uniform regardless of the particle size, the average value was determined for 10 particles. The average thickness of the composite particles was determined from the thickness of the particle coating layer and the average particle thickness of the metal particles obtained as described above according to the following calculation formula.

Average particle thickness of the composite particles = average particle thickness of the metal particles + thickness of the covering layer × 2[ table 1]

The evaluation results are shown in table 1. The composite metallic pigment composition of the present invention satisfying all of the conditions of the above items (1) to (6) obtained in each example has a high solid content, and has good stability as a coating material, little gas generation (good storage stability), and excellent brightness and hiding property, and further the occurrence of particles in a coating film is effectively suppressed.

Industrial applicability

The composite metallic pigment composition according to the invention of the present application 1, the composite metallic pigment composition obtained by the production method according to the invention of the present application 2 and 3, and the coating film obtained by using them, have excellent properties of the coating film such as storage stability, suppression of generation of particles, design properties, hiding properties, etc. for use in low VOC, water-based paint, etc. at a high level exceeding the limits of the conventional art, and therefore, can be suitably used for various applications in which metallic pigments have been used conventionally, more specifically, automobile bodies, automobile repair materials, automobile parts, household electrical appliances, etc., plastic parts, PCM coatings, highly weather-resistant coatings, heat-resistant coatings, anticorrosive coatings, ship bottom coatings, offset printing inks, gravure printing inks, screen printing inks, etc., and have high applicability in various fields of transportation machinery industry such as automobiles, electric and electronic industries such as household electrical appliances, coating industry, printing industry, etc.

Claims

1. A composite metallic pigment composition containing a composite particle having a metal particle and an oxidized metal coating formed on the surface thereof,

(1) The shape of the composite particles is scaly,

(2) Volume-based average of particle size distribution of the composite particles measured by a laser diffraction particle size distribution meterParticle diameter D ₅₀ Is 1-30 mu m in diameter,

(3) The composite particles have an average particle thickness of 20 to 300nm,

(4) The composite metal pigment composition has a solid content concentration of 70 to 95 mass%,

(5) A solvent which is hydrophilic and has a boiling point of 80 to 150 ℃ accounts for 80 mass% or more of the non-solid content of the composite metallic pigment composition,

2. The composite metallic pigment composition according to claim 1, wherein a ratio of primary particles not aggregated in the composite particles is 35% or more on a number basis.

3. The composite metallic pigment composition according to claim 1 or 2, wherein a ratio of the bent composite particles in the composite particles is 10% or less on a number basis.

4. The composite metallic pigment composition of any of claims 1 to 3 wherein at least 1 layer of said oxidized metallic coating is a silicon-containing compound layer.

5. The composite metallic pigment composition according to any of claims 1 to 4, wherein the average layer thickness of the metal oxide coating is 5 to 200nm.

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

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

8. A process for producing a composite metallic pigment composition, which comprises 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,

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 volatilization in step 3) is carried out in 3 stages or more.

10. The production method according to claim 8 or 9, wherein the moisture percentage of the solvent when the solvent is volatilized in the step 3) is 10% by mass or less.