JP7079503B6 - Gold pigment, dispersion liquid, ink, coating film and method for producing the same - Google Patents

Description

The present invention relates to gold pigments, dispersions, inks, coatings and methods of making coatings.

Traditionally, luster pigments having gold and/or gold-tone colors have been used industrially for automobile coating materials, decorative coating materials, plastics, printing inks, etc., since they provide brilliant decorative effects and excellent design properties. Although it is widely used in cosmetic preparations and the like, when gold powder containing gold itself or a composite pigment coated with gold is used as a pigment, gold is expensive and scarce, so there is a problem with versatility.

In recent years, various studies have been made on lustrous pigments (hereinafter referred to as "golden pigments") having a golden color without using gold itself.
For example, a gold interference pigment comprising a flaky substrate and at least one layer located on said substrate, said flaky substrate being a synthetically produced transparent which itself has a green intrinsic interference color. Interference pigments have been proposed in which a substrate, at least one layer comprising a mixture or mixed oxide of Fe ₂ O ₃ and TiO ₂ is located on said substrate (see, for example, US Pat. No. 5,400,000).

Japanese Patent Publication No. 2015-532676

However, the pigment described in Patent Document 1 is a layered body of metal oxides, is thick and has a large particle size, so it is difficult to apply to various printing methods such as inkjet printing. There is a problem that the feeling (lame feeling) appears remarkably and the design is inferior.

An object of the present invention is to solve the above-mentioned conventional problems and to achieve the following objects. That is, an object of the present invention is to provide a gold pigment, a dispersion liquid, an ink, a coating film, and a method for producing a coating film, which have a seamless design without a grainy feel and can realize an excellent golden color. and

Means for solving the above problems are as follows. Namely
<1> containing silicon oxide (SiOx (0<x≦2)),
Cumulative 50% volume particle diameter (D ₅₀ ) is 20 μm or less, average thickness is 100 nm or more and 200 nm or less,
A gold pigment characterized by having a composition ratio of 30 atomic % or more and 80 atomic % or less of Si and 20 atomic % or more and 70 atomic % or less of O.
<2> The gold pigment according to <1>, which has a single-layer structure.
<3> The gold pigment according to any one of <1> to <2>, which is scale-like particles.
<4> A dispersion containing the gold pigment according to any one of <1> to <3>.
<5> An ink containing the gold pigment according to any one of <1> to <3>.
<6> Containing a gold pigment containing silicon oxide (SiOx (0<x≦2)),
The coating film has an a ^* value of −5 or more and 5 or less and a b ^* value of 5 or more in the CIE Lab color system.
<7> For the gloss value (Gs20°) at an incident angle of 20° and the gloss value (Gs60°) at an incident angle of 60°, the sum (Gs20° + Gs60°) is 33 or less and the difference (Gs20° - Gs60°) is -10 or more, the coating film according to <6> above.
<8> Applying a dispersion or ink containing a gold pigment containing silicon oxide (SiOx (0<x≦2)) onto a substrate,
The dispersion or ink is applied so that the coating film of the dispersion or ink has an a ^* value of −5 or more and 5 or less and a b ^* value of 5 or more in the CIE Lab color system. It is a manufacturing method of a coating film.
<9> In the gloss value (Gs20°) at an incident angle of 20° and the gloss value (Gs60°) at an incident angle of 60°, the sum (Gs20° + Gs60°) is 33 or less and the difference (Gs20° - Gs60°) The method for producing a coating film according to <8>, wherein the dispersion or ink is applied so that at least one of -10 or more is satisfied.

According to the present invention, the above-mentioned problems in the conventional art can be solved, the above-mentioned objects can be achieved, and a gold pigment, a dispersion liquid, Inks and coatings can be provided.

FIG. 1 is a SEM photograph of the long side surface of the scale-like SiOx (0<x≦2) particles in Example 9. FIG. 2 is a cross-sectional SEM photograph of scaly SiOx (0<x≦2) particles in Example 9. FIG. 3 is a schematic diagram showing the structure of scale-like particles of Comparative Example 5. FIG. 4 is an SEM photograph of the long side surfaces of the scale-like particles in Comparative Example 5. FIG. 5 is a cross-sectional SEM photograph of scale-like particles in Comparative Example 5. FIG. 6 is a reflection spectrum of a coating film formed on a vinyl chloride printing medium in Example 1. FIG. 7 is a reflection spectrum of a coating film formed on a vinyl chloride printing medium in Example 2. FIG. 8 is a reflection spectrum of a coating film formed on a vinyl chloride printing medium in Example 9. FIG. 9 is a reflection spectrum of a coating film formed on a vinyl chloride printing medium in Comparative Example 5. FIG. FIG. 10 is a graph showing the relationship between the a ^* value and the b ^* value of the coating films in Examples 1-10 and Comparative Examples 1-5. FIG. 11 is a graph showing the relationship between the a ^* value and the b ^* value of the coating films in Examples 1-10. FIG. 12 is a graph showing the relationship between the a ^* value and the b ^* value of the coating films in Comparative Examples 1-5. 13A is an SEM photograph of the coating film in Example 9 at an inclination angle of 0°. FIG. 13B is an SEM photograph of the coating film in Example 9 at an inclination angle of 60°. 13C is an optical micrograph of the coating film in Example 9. FIG. 14A is an SEM photograph of the coating film at an inclination angle of 0° in Comparative Example 5. FIG. 14B is an SEM photograph of the coating film at an inclination angle of 60° in Comparative Example 5. FIG. 14C is an optical micrograph of the coating film in Comparative Example 5. FIG.

(gold pigment)
The gold pigment of the present invention contains silicon oxide (SiOx (0<x≦2)), has a cumulative 50% volume particle size (D ₅₀ ) of 20 μm or less, an average thickness of 100 nm or more and 200 nm or less, and has a Si content of 30 The composition ratio is from 20 atomic % to 70 atomic % and from 20 atomic % to 70 atomic %.

In the present invention, a gold pigment containing silicon oxide (SiOx (0 < x ≤ 2)), which is thinner and has a smaller particle size than before, has a seamless design without a feeling of particles, and has an excellent gold tone. colors can be realized.

Silicon (Si) has a bandgap. If the wavelength of incident light is shorter than the wavelength corresponding to the bandgap (the wavelength of the optical absorption edge), the light will not be transmitted, and the absorbed color will be the complementary color. considered to be colored.
The relationship between the wavelength of the optical absorption edge and the bandgap can be expressed by the following formula (1).
Optical absorption edge (nm) = 1239.8/bandgap (eV) Equation (1)
In this case, cadmium sulfide (bandgap: 2.6 eV) absorbs up to a wavelength of 476.8 nm (blue), so the lumps of cadmium sulfide are yellow.
In the case of Si, since the bandgap is 1.1 eV (crystallized Si), it absorbs up to a wavelength of 1127.0 nm, which is on the longer wavelength side than the visible light region, so that it becomes black. Furthermore, since Si has a high refractive index, from the following formula (1), Si has a high reflectance of about 35% for wavelengths in the visible light region and behaves as if it has metallic luster.
[Calculation formula (1)]
R (%) = {(n−1) ² +k ² }/{(n+1) ² +k ² }×100
However, in the above formula (1), R is the reflectance of normal incidence, n is the refractive index, and k is the extinction coefficient (optical constant representing light absorption).
However, it is difficult for a sparse thin film such as a deposited Si film to absorb all the incident light, and if the thickness is thin, the amount of transmitted components increases. Therefore, the balance between reflection, absorption, and transmission varies depending on the amount of Si (film thickness), and even within a thickness range of about 20 nm to 200 nm, the film is colored in various colors.

Therefore, as a result of extensive studies by the present inventors, it was found that in the case of a Si vapor deposition film, a thickness of about 70 nm is the thickness that gives the strongest golden color. As a result, the high refractive index of Si inherently influences the internal scattering of the coating film, which results in a light yellowish silver color.

Based on the above findings, the inventors of the present invention conducted further extensive studies and found that the amount of Si that develops the gold color remains unchanged, and Si is oxidized to form silicon oxide (SiOx (0 < x ≤ 2)). SiOx (0 < x ≤ 2) particles with reduced index (reduced reflection intensity), colored primarily in the complementary color of the absorbed color, thin, small-sized, and not very highly reflective. Based on this finding, it was found that due to the high orientation characteristic of SiOx (0<x≦2) particles, it has a seamless design without a grainy feel, and an excellent golden color can be realized, leading to the present invention. rice field.

The gold pigment of the present invention is preferably scaly particles. The scale-like particles are also called flaky particles, tabular particles, flake-like particles, and the like.
In the present invention, scale-like particles mean particles that have a substantially flat surface and have a substantially uniform thickness in the direction perpendicular to the substantially flat surface. Further, the scale-like particles mean particles having a very thin thickness and a substantially flat surface having a very long length. The length of the substantially flat surface is the diameter of a circle having the same projected area as that of the scaly particles.
The shape of the substantially flat surface is not particularly limited and can be appropriately selected depending on the purpose. Polygons such as hexagons, substantially heptagons, and substantially octagons, and random irregular shapes are included. Among these, substantially circular and substantially elliptical shapes are preferable.

The gold pigment preferably has a single layer structure containing silicon oxide (SiOx (0<x≦2)). The single-layer structure of the gold pigment makes it possible to form particles that are thinner and have a smaller particle diameter than conventional gold pigments with a layered structure, and can be used for general purposes in various printing methods such as inkjet printing. .

The golden pigment has a composition ratio of 30 atomic % to 80 atomic % of Si and 20 atomic % to 70 atomic % of O, and 30 atomic % to 60 atomic % of Si and 40 atomic % to 70 atomic % of O. The composition ratio is preferably atomic % or less.
By satisfying the above range of composition ratio, it is possible to obtain a gold pigment that has a seamless design without graininess and can realize an excellent gold tone color.
The composition ratio of Si and O in silicon oxide (SiOx (0<x≦2)) in the gold pigment can be measured as follows.
Directly onto the SEM sample stage, drop 3 to 5 drops of a 10 mass% butyl acetate dispersion of scaly SiOx (0 < x ≤ 2) particles as a gold pigment with a dropper, then dry and dry on the sample stage. SEM observation of the scaly SiOx (0 < x ≤ 2) particles was performed, and after focusing on the long side surfaces of the scaly SiOx (0 < x ≤ 2) particles, the composition ratio was determined by EDX analysis under the following conditions. can ask.
[conditions]
・ Energy dispersive X-ray spectrometer (EDX: Energy dispersive X-ray spectrometry, manufactured by HORIBA, Ltd.)
・Observation sample pretreatment: Pt sputtering/10 sec
Analysis conditions: acceleration voltage 20 kV, magnification × 200 k, tilt angle 0°, live time 300 sec, spectrum collection range 0 keV to 10 keV

The gold pigment contains silicon oxide (SiOx (0 < x ≤ 2)) with a purity of 95% or more (preferably 98% or more), and may contain trace amounts of impurities, but alloys with other metals is not included.

The cumulative 50% volume particle size _D50 of the gold pigment is 20 µm or less, preferably 10 µm or less, more preferably 5 µm or less, and even more preferably 0.5 µm or more and 5 µm or less.
When the cumulative 50% volume particle diameter _D50 is 20 μm or less, a gold pigment can be obtained that has a seamless design without a grainy feel and can realize an excellent gold tone color.
The cumulative 50% volume particle size (D ₅₀ ) is a particle size corresponding to 50% of the cumulative amount of volume distribution in a particle size distribution curve obtained by a laser diffraction method. It is the length obtained by averaging the long diameter and short diameter of the gold pigment particles when measured assuming. However, actual gold pigment particles are not spherical, but scale-like with long and short sides. Therefore, the _D50 is a value different from the actual length in the long side direction (major diameter) and the length in the short side direction (minor diameter) of the gold pigment particles.
The cumulative 50% volume particle size (D ₅₀ ) is measured using, for example, a laser diffraction/scattering particle size distribution analyzer (device name: Laser Micron Sizer LMS-2000e, Seishin Enterprise Co., Ltd., wet dispersion unit). It can be measured by a diffraction method using Fraunhofer's approximation method.

The average thickness of the gold pigment is 100 nm or more and 200 nm or less, preferably 120 nm or more and 180 nm or less, and more preferably 130 nm or more and 160 nm or less. When the average thickness is 100 nm or more and 200 nm or less, a gold pigment can be obtained that has a seamless design without graininess and can realize an excellent gold tone color.
The average thickness of the gold pigment is defined as the length of the shortest portion in the three-dimensional direction of the scale-like gold pigment particles.
The average thickness can be determined, for example, from scanning electron microscope (SEM) observation, X-ray fluorescence spectroscopy (XRF), ultraviolet-visible spectroscopy, etc. The average thickness of the gold pigment is SiOx (0 < x ≤ 2) It is the same as the average deposition thickness of the deposition film.
When using scanning electron microscope (SEM) observation, the average vapor deposition thickness of the SiOx (0<x≦2) vapor deposition film is 5 to 5 by cross-sectional observation using a scanning electron microscope (SEM) after powder processing. It is a value obtained by measuring the thickness of 10 SiOx (0<x≦2) particles and averaging them.
When using X-ray fluorescence spectroscopy (XRF), the average thickness can be measured by quantitative analysis.
When UV-visible spectroscopy is used, the reflectance can be measured with a UV-visible spectrophotometer and the average thickness can be calculated from the resulting spectrum.

<Method for producing gold pigment>
A method for producing a gold pigment includes a peeling layer forming step, a vapor deposition step, a peeling step, and further includes other steps as necessary.

<Peeling layer forming step>
The peeling layer forming step is a step of providing a peeling layer on the substrate, and is carried out by a peeling layer forming means.

-Base material-
The substrate is not particularly limited as long as it has a smooth surface, and various substrates can be used. Among these, resin films, metals, and composite films of metals and resin films having flexibility, heat resistance, solvent resistance, and dimensional stability can be appropriately used.
Examples of resin films include polyester films, polyethylene films, polypropylene films, polystyrene films, and polyimide films. Metals include copper foil, aluminum foil, nickel foil, iron foil, and alloy foil. Moreover, as a composite film of a metal and a resin film, there is a laminate obtained by laminating the above resin film and a metal.

-Release layer-
As the peeling layer, various organic substances that can be dissolved in the later peeling process can be used. In addition, if the organic material that constitutes the release layer is appropriately selected, the organic matter that adheres to and remains on the SiOx (0<x≦2) deposition film functions as a protective layer for the scaly SiOx (0<x≦2) particles. It is suitable because it can be
The protective layer has a function of suppressing aggregation, oxidation, elution into a solvent, etc. of scaly SiOx (0<x≦2) particles. In particular, it is preferable to use the organic material used for the peeling layer as the protective layer, because it eliminates the need for a separate surface treatment step.
Examples of organic materials constituting a release layer that can be used as a protective layer include cellulose acetate butyrate (CAB), other cellulose derivatives, polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polyacrylic acid, polyacrylamide, and copolymerized acrylic acid. Coalescing, modified nylon resins, etc. can be mentioned. These may be used individually by 1 type, and may use 2 or more types together. Among these, cellulose acetate butyrate (CAB) is preferable because of its high function as a protective layer.

The method for forming the release layer is not particularly limited and can be appropriately selected depending on the intended purpose. , knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, smoothing coating method, micro gravure coating method, reverse roll coating method, 4 roll coating method, 5 roll coating method, dip coating method, curtain coating method, slide coating method, die coating method, and the like. These may be used individually by 1 type, and may use 2 or more types together.

<Deposition process>
The vapor deposition step is a step of vapor-depositing a layer containing a gold pigment on the release layer, and is carried out by vapor deposition means. In the present invention, in order to oxidize Si, it is preferable to introduce oxygen gas and carry out vapor deposition in an oxygen atmosphere. If the range of the composition ratio of Si is 30 atomic % or more and 80 atomic % or less and O is 20 atomic % or more and 70 atomic % or less, vapor deposition can be performed without introducing oxygen gas. good.
The amount of oxygen gas to be introduced is not particularly limited and can be appropriately selected according to the purpose, but is preferably 100 sccm or more and 1000 sccm or less.

The average deposition thickness of the layer containing the gold pigment is preferably 100 nm or more and 200 nm or less, more preferably 120 nm or more and 180 nm or less, and even more preferably 130 nm or more and 160 nm or less. The average deposition thickness of the layer containing the gold pigment is the same as the average thickness of the gold pigment particles.
When the average deposition thickness of the layer containing the gold pigment is 100 nm or more and 200 nm or less, there is an advantage that it has a seamless design without a grainy feeling and an excellent golden color can be realized.
The average deposition thickness, for example, using a scanning electron microscope (Scanning Electron Microscope: SEM), to perform cross-sectional observation of the layer containing the gold pigment, 5 to 10 places thickness of the layer containing the gold pigment are measured and averaged.

The vapor deposition method is preferable to the plating method in that it is possible to form a film on a resin base material and does not generate waste liquid, etc. The sputtering method is preferable in that the degree of vacuum can be increased and the film formation speed (deposition rate) is high. more preferred.
The deposition rate in the deposition method is preferably 100 nm/sec or more, and the higher the rate, the better.

Operational factors that affect the shape, cumulative 50% volume particle diameter, and average thickness of the finally obtained gold pigment particles include the film formation method, the energy of Si that comes to the substrate (kinetic energy, temperature, etc.), and the peeling. The surface free energy of the layer, the frequency of collision with oxygen gas, the material/temperature, the cooling method/temperature of the base material, the film formation rate, and the like.

<Peeling process>
The peeling step is a step of peeling off the layer containing the gold pigment by dissolving the peeling layer, and is carried out by peeling means.
The solvent capable of dissolving the release layer is not particularly limited as long as it is capable of dissolving the release layer, and can be appropriately selected depending on the purpose. things are preferred. Water-based paints and water-based inks preferably have compatibility with water.

Examples of solvents capable of dissolving the release layer include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, octanol, dodecanol, ethylene glycol, and propylene glycol; ethers such as tetrahydrone; acetone, methyl ethyl ketone, acetylacetone, and the like. ketones; methyl acetate, ethyl acetate, butyl acetate, esters such as phenyl acetate; ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, Ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether , triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, glycol ethers such as diethylene glycol monomethyl ether acetate; phenols such as phenol and cresol; pentane , hexane, heptane, octane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, octadecane, octadecene, benzene, toluene, xylene, trimesine, nitrobenzene, aniline, methoxybenzene, and other aliphatic or aromatic hydrocarbons; dichloromethane, chloroform, trichloroethane , chlorobenzene, dichlorobenzene, and other aliphatic or aromatic chlorinated hydrocarbons; dimethylsulfoxide, and other sulfur-containing compounds; dimethylformamide, dimethylacetamide, acetonitrile, propionitrile, benzonitrile, and other nitrogen-containing compounds. These may be used individually by 1 type, and may use 2 or more types together.

By dissolving the release layer, the gold pigment-containing film is peeled from the base material to form gold pigment particles. As a result, a gold pigment dispersion can be obtained without a particular pulverization step, but pulverization and classification may be carried out as necessary. Moreover, when the primary particles of the gold pigment particles are agglomerated, they may be pulverized as necessary.
Furthermore, if necessary, various treatments may be performed for recovery of the gold pigment particles and adjustment of physical properties. For example, the particle size of the gold pigment particles may be adjusted by classification, the gold pigment particles may be recovered by a method such as centrifugation or suction filtration, or the solid content concentration of the gold pigment dispersion may be adjusted. Moreover, solvent substitution may be performed, and viscosity adjustment etc. may be performed using an additive. A dispersant may be added, but in the present invention, if an appropriate organic material is selected for the release layer, a gold pigment dispersion containing gold pigment particles with good dispersibility can be obtained. need not be added.

<Other processes>
Examples of the other steps include a step of removing the exfoliated gold pigment particles as a dispersion, and a step of recovering the gold pigment particles from the dispersion.

(dispersion liquid)
The dispersion of the present invention contains the gold pigment of the present invention, preferably an organic solvent, and optionally other components.

The content of the gold pigment is preferably 0.1% by mass or more and 50% by mass or less with respect to the total amount of the dispersion. A dry powder obtained by drying a gold pigment can also be used instead of the dispersion liquid.

<Organic solvent>
The organic solvent is not particularly limited, and any organic solvent used for stripping can be used. , amines, sulfur-containing compounds, and the like. These may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the organic solvent include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, octanol, dodecanol, ethylene glycol and propylene glycol; ethers such as tetrahydrone; ketones such as acetone, methyl ethyl ketone and acetylacetone. esters such as methyl acetate, ethyl acetate, butyl acetate, and phenyl acetate, and polyhydric alcohols such as ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1 , 2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1, 3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butane triol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol and the like.

Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. .

Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. etc.
Examples of amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide and the like.
Examples of amines include monoethanolamine, diethanolamine, triethylamine and the like.
Examples of sulfur-containing compounds include dimethylsulfoxide, sulfolane, thiodiethanol and the like.

-Other ingredients-
The other components are not particularly limited and can be appropriately selected depending on the intended purpose. Inhibitors, antifoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, antiseptic antifungal agents, rust inhibitors, pH adjusters and the like.
As the water, for example, pure water such as ion-exchanged water, ultrafiltrated water, reverse osmosis water, distilled water, or ultrapure water can be used.
As the antioxidant, for example, an aromatic compound such as dibutylhydroxytoluene or an amino acid polymer such as gelatin can be used.

(ink)
The ink of the present invention contains the gold pigment of the present invention, preferably contains an organic solvent and a binder, and further contains other components as necessary.
The ink of the present invention may be either water-based or solvent-based, but is preferably water-based from the standpoint of environmental friendliness. In addition, the gold pigment containing silicon oxide (SiOx (0 < x ≤ 2)) has a micro-sized long side, so it is weaker in reactivity with pure water at room temperature than many spherical Si nanoparticles. , suitable for water-based inks.

-gold pigment-
The content of the gold pigment is preferably 0.1% by mass or more and 50% by mass or less with respect to the total amount of the ink.
In addition, the ink may contain a luster pigment other than the gold pigment, if necessary. Other bright pigments include metallic pigments (eg, aluminum pigments, indium pigments), pigments obtained from natural mica (eg, pearl pigments), glass flake pigments, and the like.

-Organic solvent-
The organic solvent for the ink is the same as the organic solvent for the dispersant.

-binder-
The binder is not particularly limited and can be appropriately selected depending on the intended purpose. Resins, vinyl chloride resins, acryl-styrene resins, acryl-silicone resins, and the like.
When the ink contains the binder, an ink having excellent fixability and dispersibility can be obtained.
The content of the binder is not particularly limited and can be appropriately selected according to the purpose, but is preferably 0.1% by mass or more and 50% by mass or less with respect to the total amount of the ink.

-Other ingredients-
Other components in the ink are the same as other components in the dispersant.

(Coating film)
The coating film of the present invention contains a gold pigment containing silicon oxide (SiOx (0 < x ≤ 2)),
In the CIE Lab color system, the a ^* value is preferably -5 or more and 5 or less, and the b ^* value is preferably 5 or more.
The a ^* value and b ^* value in the CIE Lab color system can be calculated from the reflection spectrum at an incident angle of 5° in the wavelength range of 300 nm to 800 nm using an ultraviolet-visible-near-red spectrophotometer.

The coating film has a gloss value (Gs20°) at an incident angle of 20° and a gloss value (Gs60°) at an incident angle of 60°. °) preferably satisfies at least one of -10 or more, the sum (Gs20° + Gs60°) satisfies 7 or more and 33 or less, and the difference (Gs20°-Gs60°) satisfies at least one of 10 or more is more preferred.
The gloss value of the coating film can be measured, for example, by using a gloss meter with incident angles of 20° and 60° in a parallel light method conforming to JIS Z8741 “Specular Glossiness—Measuring Method”.
Here, the gloss value (Gs20°) at an incident angle of 20° indicates a reflection intensity close to the regular reflection component. A gloss value (Gs60°) at an incident angle of 60° indicates a reflection intensity close to a diffuse component.
The sum (Gs20°+Gs60°) indicates the sparkle due to sparkling or graininess, and if one particle of the gold pigment has uniquely high reflective properties, if it is not oriented, the light incident from 60° will also be sufficiently It will be reflected. Therefore, even if the incident angle is changed, each particle of the gold pigment seems to reflect light independently (granularity), and it looks glaring.
Therefore, in order to produce a seamless feeling (no graininess) by reducing the reflection of each particle of the gold pigment and increasing the orientation (thinning the film and reducing the particle diameter), the specular reflection component ( Gs20°) and the diffusion component (Gs60°) should not be too high.

On the other hand, the difference (Gs20°-Gs60°) indicates image clarity or specular gloss. Since it can be said that the reflected light rays contribute more to the specular glossiness, the larger the difference (Gs20°-Gs60°), the more specularly reflected the image obtained on the printing surface, and the higher the image clarity or specular glossiness. preferable.
Here, the gloss value of the coating film can be measured, for example, using a gloss meter with incident angles of 20° and 60° in a parallel light method conforming to JIS Z8741 “Specular glossiness—measurement method”. .

The coating film preferably has an a ^* value of −5 or more and 5 or less and a b ^* value of 5 or more in the CIE Lab color system, and an a ^* value of −3 or more and 3 or less and a b ^* value of 10 or more. is more preferable.
When the a ^* value and b ^* value in the CIE Lab color system are within the above numerical range, a coating film having a seamless design without graininess and capable of realizing an excellent golden color can be obtained.
The a ^* value and b ^* value in the CIE Lab color system can be calculated from the reflection spectrum at an incident angle of 5° in the wavelength range of 300 nm to 800 nm using an ultraviolet-visible-near-red spectrophotometer.

(Method for producing coating film)
In the method for producing a coating film of the present invention, a dispersion or ink containing a gold pigment containing silicon oxide (SiOx (0 < x ≤ 2)) is applied onto a substrate, and the coating film of the dispersion or ink is The dispersion or ink is applied so that the a ^* value is −5 or more and 5 or less and the b ^* value is 5 or more in the CIE Lab color system.
In this case, in the gloss value (Gs20°) at an incident angle of 20° and the gloss value (Gs60°) at an incident angle of 60°, the sum (Gs20° + Gs60°) is 33 or less, and the difference (Gs20° - Gs60°) It is preferable to apply the dispersion liquid or the ink so that at least one of -10 or more is satisfied.

The substrate is not particularly limited, and various substrates can be used. Examples thereof include resin films, glass, metals, composite films of metals and resin films, and the like.

The coating film of the invention can be produced using the dispersion of the invention or the ink of the invention.
The method for applying the dispersion containing the gold pigment or the ink onto the substrate is not particularly limited and can be appropriately selected depending on the purpose. , offset coating method, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, smoothing coating method , micro gravure coating, reverse roll coating, four-roll coating, five-roll coating, dip coating, curtain coating, slide coating, die coating, drip coating and the like. These may be used individually by 1 type, and may use 2 or more types together. Among these, the spin coating method, the ink jet method, the bar coating method, and the drip coating method are particularly preferable because they have a seamless design without graininess and can realize an excellent golden color.

<Application>
The gold pigment of the present invention has a seamless design without a grainy feel and can realize excellent gold tone colors, so it is widely used in various fields. It is used for bright paints for painting in applications such as automobile interior and exterior parts, home appliances, and building materials, conductive pigments for conductive pastes, bright pigments that give decorative films a metallic design, and metallic filaments for 3D printers. It is applied to luster pigments that are kneaded into metallic design sheets and films in melt extrusion and casting methods.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1)
A polyethylene terephthalate (PET) film with an average thickness of 12 μm is coated with a solution containing 5% by mass of cellulose acetate butyrate (CAB) by gravure coating, dried at 110° C. or higher and 120° C. or lower, and peeled off. formed a layer. The coating amount of cellulose acetate butyrate (CAB) was 0.06 g/m ² ±0.01 g/m ² . On the release layer, Si is deposited at a deposition rate of 277 Å/sec by film formation under high pressure by EB heating/vacuum deposition, and SiOx (0<x≤2) is deposited with an average deposition thickness of 120 nm. A film was formed.
Next, butyl acetate is sprayed on the PET film surface on which the release layer and the SiOx (0<x≦2) vapor deposition film are formed to dissolve the release layer, and the SiOx (0<x≦2) vapor deposition film is scraped with a doctor blade. Dropped. The obtained SiOx (0<x≦2) particles were scaly.
Next, the resulting mixture of SiOx (0<x≦2) particles and butyl acetate was pulverized using a fine pulverizer. As described above, scale-like SiOx (0<x≦2) particles having a single layer structure were obtained as a gold pigment.

(Examples 2 to 10 and Comparative Examples 1 to 4)
In Example 1, except that the vapor deposition conditions were changed to those shown in Table 1, scale-like SiOx ( 0<x≦2) particles were obtained.
In Examples 2 to 10 and Comparative Examples 3 to 4, the amount of oxygen gas shown in Table 1 was introduced into the space until Si reached the substrate, and Si was deposited in an oxygen atmosphere.
In Comparative Examples 1 and 2, Si was vapor-deposited under a vacuum atmosphere in which oxygen gas was not introduced into the space until Si reached the substrate.
The scaly SiOx (0<x≦2) particles of Examples 2 to 10 and Comparative Examples 1 to 4 all had a single layer structure.
Here, FIG. 1 shows an SEM photograph of the long side surface of the scale-like SiOx (0<x≦2) particles of Example 9. As shown in FIG. FIG. 2 shows a cross-sectional SEM photograph of the scale-like SiOx (0<x≦2) particles of Example 9. As shown in FIG. It can be seen from FIG. 2 that the scale-like SiOx (0<x≦2) particles of Example 9 have a monolayer structure.

(Comparative Example 5)
Zenexo (registered trademark) Goldenshine 21YY manufactured by Schlenk was used as Comparative Example 5 as a gold pigment. A schematic diagram of the scale-like particles of Comparative Example 5 is shown in FIG. The scale-like particles of Comparative Example 5 in FIG. 3 have Al in the center and have a laminated structure of Fe ₂ O ₃ and SiO ₂ . 4 shows a SEM photograph of the long side of the scale-like particles of Comparative Example 5. As shown in FIG. A cross-sectional SEM photograph of the scale-like particles of Comparative Example 5 is shown in FIG. It can be seen from FIG. 5 that the scaly particles of Comparative Example 5 have a laminated structure.

Next, for each obtained scale-like particle, the average thickness of the scale-like particle and the cumulative 50% volume particle size ( _D50 ) were measured as follows. The thickness of the scaly particles is the same as the thickness of the deposited film. Table 1 shows the results.

<Cumulative 50% volume particle diameter (D ₅₀ ) of scale-like particles>
Using a laser diffraction/scattering particle size distribution analyzer (equipment name: Laser Micron Sizer LMS-2000e, manufactured by Seishin Enterprise Co., Ltd., a wet dispersion unit), using a laser diffraction method, using Fraunhofer's approximation method, scaly The cumulative 50% volume particle size ( _D50 ) of the particles was measured.

<Average thickness of scale-like particles>
The average thickness of the scaly particles is obtained by dropping 3 to 5 drops of a 10% by mass butyl acetate dispersion directly onto the SEM sample stage with a dropper and then drying it as a sample. , the edge portions (thickness) of the scaly particles were observed at a total of 10 points, and the average value was calculated.
[conditions]
・ Scanning electron microscope (SEM: Scanning Electron Microscope) HITACHI S-4700 (manufactured by Hitachi, Ltd.)
・Observation sample pretreatment: Pt sputtering/10 sec to 20 sec
・Observation conditions: acceleration voltage 5 kV to 10 kV, various magnifications and angles

<Composition ratio of Si and O in scale-like particles>
After dropping 3 to 5 drops of 10% by mass butyl acetate dispersion directly onto the SEM sample table with a dropper, it is dried, dried on the sample table, and subjected to SEM observation of the scale-like particles, focusing on the long side surface of the scale-like particles. After combining, the composition ratio of Si and O was measured by EDX analysis under the following conditions.
[conditions]
・ Energy dispersive X-ray spectrometer (EDX: Energy dispersive X-ray spectrometry, manufactured by HORIBA, Ltd.)
・Observation sample pretreatment: Pt sputtering/10 sec
Analysis conditions: acceleration voltage 20 kV, magnification × 200 k, tilt angle 0°, live time 300 sec, spectrum collection range 0 keV to 10 keV

<Formation of coating film>
- Formation of Bar Coating Film on Vinyl Chloride Printing Media -
Each scaly particle was prepared in a 10% by weight butyl acetate dispersion, and subjected to a Roland D.C. G. Co., Ltd. vinyl chloride printing media (glossy vinyl chloride, MV-G-18G), using a bar coater (#4, Marukyo Giken Co., Ltd.), each dispersion was applied at room temperature (25 ° C.), A bar coat film was formed by drying at normal temperature (25°C).

- Formation of bar coat film on polyethylene terephthalate (PET) film -
Each scaly particle was prepared in a 10% by mass butyl acetate dispersion, placed on a polyethylene terephthalate (PET) film (thickness 75 μm, manufactured by Toyobo Co., Ltd.) using a bar coater (#4, manufactured by Marukyo Giken Co., Ltd.), Each dispersion was applied at normal temperature (25°C) and dried at normal temperature (25°C) to form a bar coat film. In addition, in order to provide hiding power so that the total light transmittance is 10% or less, for Comparative Example 5, a 15% by mass butyl acetate dispersion was prepared and applied to a PET film in the same manner as above.

<Measurement of gross value>
-Bar coat film on vinyl chloride printing media-
For each bar coat coating film formed on vinyl chloride printing media, the bar coat surface was used as the measurement surface, and the gloss value was measured. The gloss value is measured using a gloss meter (Nippon Denshoku Industries Co., Ltd., VG-7000), using a parallel light method in accordance with JIS Z8741 "Specular gloss-measurement method", the gloss value at an incident angle of 20 ° ( Gs20°) and the gloss value at an incident angle of 60° (Gs60°) were measured, and the sum (Gs20°+Gs60°) (sparkling) was calculated from these gloss values. Table 2 shows the results.

- Bar coat coating on polyethylene terephthalate (PET) film -
For each bar coat coating film formed on a PET film, a black vinyl tape was attached to the bar coat surface, and the gloss value was measured from the PET surface in a lined state. The gloss value is measured using a gloss meter (Nippon Denshoku Industries Co., Ltd., VG-7000), using a parallel light method in accordance with JIS Z8741 "Specular gloss-measurement method", the gloss value at an incident angle of 20 ° ( Gs20°) and the gloss value at an incident angle of 60° (Gs60°) were measured, and the difference (Gs20°-Gs60°) (specular glossiness) was calculated from these gloss values. Table 3 shows the results.

<Hue (L ^* value, a ^* value, b ^* value) and reflection spectrum>
-Bar coat film on vinyl chloride printing media-
For each bar coat coating film formed on vinyl chloride printing media, the bar coat surface is used as the measurement surface, and an ultraviolet-visible near-red spectrophotometer (manufactured by Shimadzu Corporation, SolidSpec-3700) is used to measure the wavelength range of 300 nm to 800 nm. Reflection spectra were measured within a range of 5° incident angle, and the L ^* value, a ^* value, and b ^* value were obtained. Table 2 shows the results.

FIG. 6 shows the reflection spectrum of the bar coat film formed on the vinyl chloride printing medium in Example 1. In FIG. FIG. 7 shows the reflection spectrum of the bar coat film formed on the vinyl chloride printing medium in Example 2. FIG. 8 shows the reflection spectrum of the bar coat film formed on the vinyl chloride printing medium in Example 9. The reflection spectrum of the bar coat film formed on the vinyl chloride printing medium in Comparative Example 5 is shown in FIG.
From the results of FIGS. 6 to 9, the reflection spectra of Examples 1, 2, 9 and Comparative Example 5 show an absorption range of 400 to 450 nm, and all of them have an excellent golden color. all right.

Next, FIG. 10 shows the relationship between the a ^* value and the b ^* value of the bar coat coating films in Examples 1-10 and Comparative Examples 1-5. FIG. 11 shows the relationship between the a ^* value and the b ^* value of the bar coat coating films in Examples 1-10. FIG. 12 shows the relationship between the a ^* value and the b ^* value of the bar coat coating films in Comparative Examples 1-5.
From the results of FIGS. 10 to 12, Examples 1 to 10 and Comparative Example 5 satisfy the a ^* value of -5 or more and 5 or less and the b ^* value of 5 or more, and all of them achieve excellent golden color. It turned out to be done. On the other hand, Comparative Examples 1 to 4 could not achieve a golden color.

- Bar coat coating on polyethylene terephthalate (PET) film -
For each bar coat coating film formed on the PET film, a black vinyl tape is attached to the bar coat surface, and an ultraviolet-visible near-red spectrophotometer (SolidSpec-3700, manufactured by Shimadzu Corporation) is measured from the PET surface in a lined state. A reflection spectrum was measured at an incident angle of 5° in a wavelength range of 300 nm to 800 nm, and the L ^* value, a ^* value, and b ^* value were obtained. Table 3 shows the results.

Next, FIG. 13A is an SEM photograph of the coating film at an inclination angle of 0° in Example 9, FIG. 13B is an SEM photograph of the coating film at an inclination angle of 60° in Example 9, and FIG. 1 shows an optical micrograph of the coating film in . 14A is an SEM photograph of the coating film at an inclination angle of 0° in Comparative Example 5, FIG. 14B is an SEM photograph of the coating film at an inclination angle of 60° in Comparative Example 5, and FIG. 14C is the coating film in Comparative Example 5. shows an optical micrograph of Digital Microscope SE-1300 manufactured by Celmic Co., Ltd. was used as an optical microscope, and an objective lens SEL-270 (270 to 2700 times) was used to focus.
Comparing the bar coat coating film of Example 9 in FIGS. 13A to 13C with the bar coat coating film of Comparative Example 5 in FIGS. It is recognized that it is occurring.

<Sensory evaluation of coating film>
Five evaluators evaluated the color of each coating film. In addition, for each coating film, 5 evaluators evaluated the seamless feeling (no grainy feeling) according to the following criteria. Table 2 shows the results.
[Evaluation Criteria for Seamless Feeling]
○: The presence of particles is not visually observed △: Depending on the coating method, the presence of some particles is visually observed ×: Regardless of the coating method, the particles are clearly independent by visual inspection presence of

From the results of Tables 1 to 3, "containing silicon oxide (SiOx (0 < x ≤ 2)), having a cumulative 50% volume particle size (D ₅₀ ) of 20 µm or less, an average thickness of 100 nm or more and 200 nm or less, Examples 1 to 10 that satisfy all the requirements that Si is 30 atomic % or more and 80 atomic % or less and O is 20 atomic % or more and 70 atomic % or less are "silicon oxide (SiOx (0 < x ≤ 2) includes), has a cumulative 50% volume particle diameter (D ₅₀ ) of 20 µm or less, an average thickness of 100 nm or more and 200 nm or less, Si content of 30 atomic percent or more and 80 atomic percent or less, and O content of 20 atomic percent or more and 70 atoms. % or less.” Compared to Comparative Examples 1 to 5, which do not satisfy at least one of the requirements, it has a seamless design without a grainy feeling, and a golden pigment that can realize an excellent golden color. was obtained.

Claims (9)

containing silicon oxide (SiOx (0 < x ≤ 2)),
Cumulative 50% volume particle diameter (D ₅₀ ) is 20 μm or less, average thickness is 100 nm or more and 200 nm or less,
A gold pigment having a composition ratio of 30 atomic % or more and 80 atomic % or less of Si and 20 atomic % or more and 70 atomic % or less of O. 2. The gold pigment according to claim 1, which has a single layer structure. The gold pigment according to any one of claims 1 and 2, which is scale-like particles. A dispersion containing the gold pigment according to any one of claims 1 to 3. An ink comprising the gold pigment according to any one of claims 1 to 3. Containing a gold pigment containing silicon oxide (SiOx (0 < x ≤ 2)),
A coating film characterized by having an a ^* value of -5 or more and 5 or less and a b ^* value of 5 or more in the CIE Lab color system. For the gloss value (Gs20°) at an incident angle of 20° and the gloss value (Gs60°) at an incident angle of 60°, the sum (Gs20° + Gs60°) is 33 or less, and the difference (Gs20° - Gs60°) is -10. The coating film according to claim 6, which satisfies at least one of the above. Applying a dispersion or ink containing a gold pigment containing silicon oxide (SiOx (0 < x ≤ 2)) onto a substrate,
The dispersion or ink is applied so that the coating film of the dispersion or ink has an a ^* value of −5 or more and 5 or less and a b ^* value of 5 or more in the CIE Lab color system. A method for producing a coating film. For the gloss value (Gs20°) at an incident angle of 20° and the gloss value (Gs60°) at an incident angle of 60°, the sum (Gs20° + Gs60°) is 33 or less, and the difference (Gs20° - Gs60°) is -10. 9. The method for producing a coating film according to claim 8, wherein the dispersion or ink is applied so as to satisfy at least one of the above.

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