JP2012251070A - Ink set and recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set used for forming a recorded matter having high image precision and excellent gloss peculiar to a metal, and to provide a recorded matter having high image precision and excellent gloss peculiar to a metal.SOLUTION: The ink set includes a plurality of ultraviolet-curable inkjet inks ejecting by an inkjet system. The ultraviolet-curable inkjet inks include a first ink containing first particles in flaky form applied surface treatment on surfaces of the metal particles, and a second ink containing second particles whose surface tension is larger than that of the first particle. The surface tension applied on the first particles is treatment for film forming from a film containing a fluorine compound on surfaces of the first particles. The second particles are preferably particles composing a film containing a phosphoric acid ester-based compound applied on surfaces of the metal particles.

Description

  The present invention relates to an ink set and a recorded matter.

There is a high demand for printed materials having a metallic luster against the background of excellent aesthetics and texture unique to metals.
Conventionally, when producing a printed matter having a metallic luster, not only gravure printing or screen printing using an ink containing metal particles such as aluminum particles, but also foil stamping printing or thermal transfer printing using a metal foil are known.

However, these printing methods require a large-scale or expensive apparatus, and a lot of ink and metal foil are discarded after printing, so that the running cost is high. There are also problems such as high noise during printing.
Furthermore, these methods also have problems such as forming a fine pattern and being difficult to apply to a curved surface portion.

  On the other hand, as a recording method on a recording medium using a composition containing a pigment or a dye, a recording method using an inkjet method is used. The ink jet method is excellent in that it can be suitably applied to formation of a fine pattern and recording on a curved surface portion. In recent years, compositions (ultraviolet curable ink-jet inks) that are cured when irradiated with ultraviolet rays have been used in the ink jet method in order to make the abrasion resistance, water resistance, solvent resistance, etc. particularly excellent. (For example, refer to Patent Document 1).

  However, in an ultraviolet curable ink-jet ink, when a metal powder is applied instead of a pigment or a dye, the ultraviolet transmittance into the ink is lowered, and therefore, it is necessary to irradiate ultraviolet rays for a long time. There has been a problem that the definition of the recorded matter is lowered due to ink bleeding. Further, when the content of the metal powder in the ink is lowered to increase the ultraviolet transmittance, there has been a problem that characteristics such as glossiness (high luminance and brightness) peculiar to the metal cannot be sufficiently exhibited in the recorded matter.

JP 2009-57548 A

  An object of the present invention is to provide an ink set that can be suitably used for forming a recorded matter having high definition and excellent glossiness peculiar to metal, and to high gloss and glossiness peculiar to metal. It is to provide an excellent record.

Such an object is achieved by the present invention described below.
The ink set of the present invention is an ink set comprising a plurality of ultraviolet curable ink jet inks ejected by an ink jet method,
The ultraviolet curable ink-jet ink has a scaly shape, and includes a first ink containing first particles obtained by surface-treating the surface of metal particles, and a first ink having a surface tension larger than that of the first particles. And a second ink containing two particles.
As a result, an ink set can be obtained that can be suitably used for forming a recorded matter with high definition and excellent glossiness peculiar to metal.

In the ink set of the present invention, it is preferable that the surface treatment applied to the first particles is a treatment for forming a film containing a fluorine-based compound on the surface of the metal particles.
Thereby, sufficient liquid repellency is imparted to the surface of the first particle, and the surface tension of the first particle can be surely made smaller than that of the second particle. Therefore, in the printing part manufactured using the first ink, it is possible to more effectively exhibit characteristics such as glossiness inherent in the metal material. Further, by using the first particles provided with a coating containing a fluorine-based compound, the first ink is manufactured even when the first ink contains a polymerizable compound having a large surface tension. In the recorded matter, the first particles can be reliably arranged (leafed) in the vicinity of the outer surface of the printing portion.

In the ink set of the present invention, it is preferable that the second particles have a scaly shape.
As a result, even if the second particles are not arranged on the surface of the ejected matter and dispersed therein, a recorded matter exhibiting a sufficient glossiness can be obtained when it is cured. For this reason, the curability of the discharged material and the glossiness of the recorded material can be made highly compatible.

In the ink set of the present invention, it is preferable that the second particles are particles obtained by performing a surface treatment on the surface of the metal particles so that the surface tension is larger than that of the first particles.
Thereby, even if the composition of the metal particles is the same, the first particles and the second particles can be produced only by changing the kind of the surface treatment, so that the behavior of the particles can be controlled finely. Is useful.

In the ink set of the present invention, it is preferable that the surface treatment applied to the second particles is a treatment of forming a film containing a phosphate ester compound on the surface of the metal particles.
As a result, appropriate liquid repellency is imparted to the surface of the second particles, the surface of the second particles has a larger surface tension than the first particles, and the second particles are contained in the discharged material. It will surely disperse.

In the ink set of the present invention, it is preferable that the metal particles in the first particles are mainly composed of aluminum.
Since aluminum is excellent in glitter, an ink set capable of producing a recorded matter with particularly high metallic gloss can be obtained.
In the ink set of the present invention, it is preferable that the metal particles in the first particles and the metal particles in the second particles are composed of metal materials having the same composition.
As a result, if the particle sizes are approximately the same, the mass of the second particles is approximately the same as the mass of the first particles, and it becomes easier to control the particle behavior in the discharge according to the surface condition. For this reason, by appropriately setting the presence / absence and type of the surface treatment, it becomes easy to achieve both the curability of the discharged material and the glossiness of the recorded material.

In the ink set of the present invention, it is preferable that an average particle diameter of the first particles is 500 nm or more and 2.0 μm or less.
As a result, the surface area of the first particles is optimized while further improving the glossiness and luxury of the printed part produced using the first ink, and the storage stability and ejection of the first ink are optimized. Stability can be further improved.

In the ink set of the present invention, it is preferable that the first ink contains phenoxyethyl acrylate as a polymerizable compound that is polymerized by irradiation with ultraviolet rays.
As a result, the storage stability of the first ink is excellent, the reactivity of the first ink after ejection by the ink jet method is particularly excellent, and the productivity of recorded matter is particularly excellent. In addition, the printed portion to be formed can have particularly excellent abrasion resistance and the like.

In the ink set of the present invention, the first ink includes, as the polymerizable compound, 2- (2-vinyloxyethoxy) ethyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate in addition to the phenoxyethyl acrylate. It is preferable to include at least one selected from the group consisting of acrylate and 4-hydroxybutyl acrylate.
Accordingly, the storage stability of the first ink is particularly excellent, the reactivity of the first ink after ejection by the ink jet method is particularly excellent, and the productivity of the recorded matter is particularly excellent. In addition, it is possible to further improve the abrasion resistance and the like of the printed portion to be formed.

In the ink set of the present invention, the first ink preferably contains at least one of dimethylol tricyclodecane diacrylate and amino acrylate as a polymerizable compound that is polymerized by irradiation with ultraviolet rays.
As a result, the storage stability of the first ink can be further improved, and the abrasion resistance and the like of the printed portion to be formed can be further improved.

The recorded matter of the present invention has a first ink that has a scaly shape and includes surface-treated metal particles, and is hardened by irradiation with ultraviolet rays. The second ink containing second particles having a large surface tension and cured by irradiation with ultraviolet rays is applied to the same position on the recording medium by an inkjet method, and is manufactured by irradiating with ultraviolet rays. To do.
Thereby, it is possible to obtain a recorded matter having high definition and excellent glossiness peculiar to metal.

The recorded matter of the present invention is preferably provided with the first ink and the second ink so that the content rate of the second particles is larger than the content rate of the first particles.
As a result, a recorded matter having a minimum curability necessary to ensure definition and a minimum light reflectivity necessary to ensure aesthetics can be obtained. That is, the balance between the curability of the discharged material and the glossiness of the recorded material can be further optimized.

Hereinafter, preferred embodiments of the present invention will be described in detail.
[Ink set]
By the way, conventionally, metal plating, foil press printing using a metal foil, thermal transfer using a metal foil, and the like have been used as a method for producing a decorative product exhibiting a glossy appearance.
However, these methods have a problem that it is difficult to form a fine pattern or to apply to a curved surface portion. Also, foil stamp printing has a problem that it is difficult to respond to multi-product production because of low on-demand.

  On the other hand, as a recording method on a recording medium using a composition containing a pigment or a dye, a recording method using an inkjet method is used. The ink jet method is excellent in that it can be suitably applied to formation of a fine printed portion and recording on a curved portion. In recent years, compositions (ultraviolet curable ink-jet inks) that are cured when irradiated with ultraviolet rays have been used in the ink jet method in order to make the abrasion resistance, water resistance, solvent resistance, etc. particularly excellent. Yes.

  However, in an ultraviolet curable ink-jet ink, when a metal powder is applied instead of a pigment or a dye, the ultraviolet transmittance into the ink is lowered, and therefore, it is necessary to irradiate ultraviolet rays for a long time. Problems such as ink smearing, which decreases the definition of the recorded matter, and when the content of the metal powder in the ink is lowered to increase the ultraviolet transmittance, unevenness occurs in the recorded matter, There has been a problem in that properties such as glossiness (high luminance and lightness) peculiar to metals are not sufficiently exhibited in objects.

Therefore, the inventor has intensively studied for the purpose of solving the above problems, and as a result, has reached the present invention. That is, the ink set of the present invention includes a plurality of types of ultraviolet curable ink jet inks (inks) ejected by an ink jet method, and includes a first ink containing first particles and a second particle. Among these, the first particles are scaly and the surface of the metal particles is subjected to surface treatment, and the second particles are the first inks. The surface tension is larger than that of the particles.
By providing such a first ink and a second ink, the ink set of the present invention can form a recorded matter with high definition and excellent metal-specific glossiness.

≪First ink≫
The first ink as the ultraviolet curable inkjet ink constituting the ink set of the present invention is ejected by an inkjet method, and includes first particles and a polymerizable compound that is polymerized by irradiation with ultraviolet rays. It is a waste.
<First particle>
As described above, the first ink constituting the ink set of the present invention has a scaly shape, and includes a large number of first particles obtained by surface-treating the surface of metal particles.

  The shape of the first particle is not particularly limited, and examples thereof include a substantially spherical shape, a scale shape, and a needle shape. Among these, it is preferable that the first particles have a scaly shape. When particles having such a shape are ejected as droplets onto a recording medium by an ink jet method, they are naturally arranged such that the main surface thereof conforms to the surface shape of the recording medium. As a result, the obtained printed part has excellent light reflection characteristics based on the metal particles arranged in a certain direction, and fully expresses the metallic luster inherent to the metal material. It becomes. Therefore, the obtained printed part is particularly excellent in aesthetics and texture.

In the present invention, scaly means an area when observed from a predetermined angle (when viewed in plan), such as a flat plate or curved plate, from an area observed from an angle orthogonal to the observation direction. In particular, the area S ₁ [μm ² ] when observed from the direction in which the projected area is maximum (when viewed in plan) and the direction orthogonal to the observation direction are observed. The ratio (S ₁ / S ₀ ) to the area S ₀ [μm ² ] when observed from the direction in which the area is maximum is preferably 2 or more, more preferably 5 or more, and still more preferably 8 or more. is there. As this value, for example, it is possible to observe an arbitrary 10 particles and adopt an average value of values calculated for these particles.

  Although the constituent material of the first particles is not particularly limited, for example, magnesium, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, ruthenium, palladium, Examples thereof include single metals such as silver, cadmium, indium, tin, antimony, hafnium, tantalum, tungsten, osmium, iridium, platinum, gold, lead, and bismuth, or alloys and mixtures thereof. Examples of the alloy include stainless steel, brass, duralumin, sendust, Ni—Fe alloy, and the like.

  Among these, from the viewpoint of light reflection characteristics, metal particles mainly composed of aluminum are preferably used. Since aluminum is excellent in glitter, an ink set capable of producing a recorded matter with particularly high metallic gloss can be obtained. The main material is an aluminum-based material having an aluminum content of more than 50% by mass, and refers to a material containing an aluminum alloy or the like in addition to an aluminum simple substance.

Moreover, it is preferable that the said constituent material is contained 60 mass% or more in a metal particle, and it is preferable that 70 mass% or more is contained. In this case, the components other than the above-described constituent materials include components inevitably mixed during the production of metal particles, such as boron, carbon, nitrogen, oxygen, fluorine, silicon, phosphorus, sulfur, arsenic, selenium. , Tellurium and the like.
Further, the first metal powder may have different constituent materials between the surface layer and the inside of the particle. In this case, the constituent material of the surface layer may be a material as described above, and the internal constituent material is not particularly limited, and may be a resin material, a ceramic material, or the like in addition to a metal material different from the surface layer. On the other hand, for forming the surface layer, for example, various vapor deposition methods, various plating methods and the like are used.

The average particle diameter of the first particles is preferably 500 nm or more and 2 μm or less, and more preferably 800 nm or more and 1.8 μm or less. As a result, the surface area of the first particles is optimized while further improving the glossiness and luxury of the printed part produced using the first ink, and the storage stability and ejection of the first ink are optimized. Stability can be further improved. In the present invention, the average particle diameter means the average particle diameter based on the number, and the average diameter of perfect circles having the same area as the area S ₁ when observed from the direction in which the projected area is maximized. The value.

  The content of the first particles in the first ink is preferably 0.1% by mass or more and 5% by mass or less, and more preferably 0.5% by mass or less and 3% by mass or less. As a result, it is possible to suppress a significant increase in the catalytic action of the metal particles while further improving the glossiness and high-quality feeling of the printed portion produced using the first ink. This catalytic action is an action in which the metal particles contained in the ink accelerate the polymerization reaction of the polymerizable compound contained in the ink. When the polymerization reaction of the polymerizable compound proceeds, the ink being stored becomes Since it will harden | cure unintentionally, it is necessary to suppress such a catalytic action as much as possible. When the content of the first particles is within the above range, such a catalytic action can be minimized, and the first ink capable of highly satisfying the above-described glossiness, high-grade feeling and storage stability can be obtained. can get.

  Such metal particles may be produced by any method, for example, a pulverization method for pulverizing a coarse powder obtained by pulverizing an ingot or the like to a desired particle size, a vapor phase such as vapor deposition, etc. A method of peeling and pulverizing a metal film formed on a film by a film forming method or the like (particularly a method of peeling and pulverizing in a liquid and dispersing in the liquid), a chemical granulation method, etc. It can be manufactured by a method.

  Among these, metal particles obtained by forming a metal film on a film by a vapor deposition method and then pulverizing the metal film are preferably used. The metal particles obtained in this manner more effectively express the glossiness inherent in the metal. Moreover, the dispersion | variation in a characteristic between each particle | grain can be suppressed. Further, by using this method, even relatively thin metal particles can be efficiently produced.

Examples of the film used include a plastic film such as polyethylene terephthalate. The film may have a film forming surface provided with a release agent or the like.
Moreover, it is preferable that the said grinding | pulverization is performed by providing an ultrasonic vibration to the said metal film in a liquid. Thereby, generation | occurrence | production of the dispersion | variation in the magnitude | size, shape, and characteristic between each particle | grain can be suppressed.

  Moreover, when pulverizing by the method as described above, the liquid includes alcohols such as methanol, ethanol, propanol and butanol, n-heptane, n-octane, decane, dodecane, tetradecane, toluene, xylene, cymene, Hydrocarbon compounds such as durene, indene, dipentene, tetrahydronaphthalene, decahydronaphthalene, cyclohexylbenzene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, Diethylene glycol monobutyl ether acetate, diethylene glycol n-butyl ether, tripro Len glycol dimethyl ether, triethylene glycol diethyl ether, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, ether compounds such as p-dioxane, propylene carbonate, γ-butyrolactone, N-methyl-2-pyrrolidone , N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), dimethyl sulfoxide, cyclohexanone, acetonitrile and the like can be preferably used. It is preferable to use one containing two or more selected from the group consisting of such liquids. Thereby, the variation in size, shape, and characteristics among the particles can be made particularly small while preventing unintentional oxidation of the metal particles.

Moreover, you may make it use the metal powder manufactured by various atomization methods.
The atomization method is a method in which a molten metal (molten metal) is made to collide with a coolant such as water or gas, and is pulverized. For this reason, metal powder with a uniform particle size is obtained. Therefore, the 1st ink which can manufacture a highly uniform printing part is obtained by using the metal powder manufactured by the atomizing method. Further, in the atomization method, since coarse particles are hardly generated, the discharge stability of the first ink can be further improved.

  In the water atomization method, the metal produced by the water atomization method collides with water to make a powder, so the particles produced by the water atomization method are oxidized on the surface and become highly chemically stable. The reactivity with the monomer is low. For this reason, it is possible to further increase the brightness and brightness of the printed portion formed using the first ink, and as a result, it is possible to form a printed portion having particularly excellent gloss as the entire ink set. it can. In addition, the storage stability and ejection stability of the first ink can be further improved.

Moreover, in order to make a metal particle into a scaly shape, after manufacturing a metal particle by the atomizing method, what is necessary is just to give a rolling process. As the rolling process, for example, a process using roll rolling, a ball mill, a stamp mill, or the like is used.
The first particles are obtained by surface-treating the surface of the metal particles as described above, and have a surface tension smaller than that of the second particles. Such first particles have improved liquid repellency with respect to the liquid phase component in the first ink, and the first particles can be reliably (leafed) in the vicinity of the outer surface of the printing portion. As a result, the recorded matter has a glossiness peculiar to metals.

Examples of the surface treatment applied to the first particles include a treatment for imparting liquid repellency to the surface of the first particles in the first ink. Specifically, a surface modification treatment that modifies the surface of the metal particles to impart liquid repellency, a film formation treatment that forms a film on the surface of the metal particles, and the like.
Among these, as a constituent material of the film formed on the surface of the metal particles, any material that imparts liquid repellency to the surface of the first particles may be used. For example, a coupling agent, a phosphate ester compound, Examples thereof include carboxylic acid compounds. Hereinafter, each material will be described in detail.

(Coupling agent)
Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. In particular, a silane compound having a silyl group and a hydrocarbon group (silane coupling agent) is preferably used. Specific examples of such compounds include dimethyldimethoxysilane, diethyldiethoxysilane, 1-propenylmethyldichlorosilane, propyldimethylchlorosilane, propylmethyldichlorosilane, propyltrichlorosilane, propyltriethoxysilane, propyltrimethoxysilane, styryl. Ethyltrimethoxysilane, tetradecyltrichlorosilane, 3-thiocyanatepropyltriethoxysilane, p-tolyldimethylchlorosilane, p-tolylmethyldichlorosilane, p-tolyltrichlorosilane, p-tolyltrimethoxysilane, p-tolyltriethoxysilane , Di-n-propyldi-n-propoxysilane, diisopropyldiisopropoxysilane, di-n-butyldi-n-butyroxysilane, di-sec-butyldi sec-Butyloxysilane, Di-t-butyldi-t-Butyloxysilane, Octadecyltrichlorosilane, Octadecylmethyldiethoxysilane, Octadecyltriethoxysilane, Octadecyltrimethoxysilane, Octadecyldimethylchlorosilane, Octadecylmethyldichlorosilane, Octadecylmethoxydichlorosilane, 7- Octenyldimethylchlorosilane, 7-octenyltrichlorosilane, 7-octenyltrimethoxysilane, octylmethyldichlorosilane, octyldimethylchlorosilane, octyltrichlorosilane, 10-undecenyldimethylchlorosilane, undecyltrichlorosilane, vinyldimethylchlorosilane, Methyloctadecyldimethoxysilane, methyldodecyldiethoxysilane, methylocta Sildimethoxysilane, methyloctadecyldiethoxysilane, n-octylmethyldimethoxysilane, n-octylmethyldiethoxysilane, triacontyldimethylchlorosilane, triacontyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n- Propoxysilane, Methylisopropoxysilane, Methyl-n-Butyloxysilane, Methyltri-sec-Butyloxysilane, Methyltri-t-Butyloxysilane, Ethyltrimethoxysilane, Ethyltriethoxysilane, Ethyltri-n-propoxysilane, Ethylisopropoxysilane, Ethyl- n-Butyloxysilane, Ethyltri-sec-Butyloxysilane, Ethyltri-t-Butyloxysilane, n-Propyltrimethoxysilane, Iso Butyltrimethoxysilane, n-hexyltrimethoxysilane, hexadecyltrimethoxysilane, n-octyltrimethoxysilane, n-dodecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-propyltriethoxysilane, isobutyltriethoxysilane N-hexyltriethoxysilane, hexadecyltriethoxysilane, n-octyltriethoxysilane, n-dodecyltrimethoxysilane, n-octadecyltriethoxysilane, 2- [2- (trichlorosilyl) ethyl] pyridine, 4- [2- (Trichlorosilyl) ethyl] pyridine, diphenyldimethoxysilane, diphenyldiethoxysilane, 1,3- (trichlorosilylmethyl) heptacosane, dibenzyldimethoxysilane, dibenzyldiethoxysilane , Phenyltrimethoxysilane, phenylmethyldimethoxysilane, phenyldimethylmethoxysilane, phenyldimethoxysilane, phenyldiethoxysilane, phenylmethyldiethoxysilane, phenyldimethylethoxysilane, benzyltriethoxysilane, benzyltrimethoxysilane, benzylmethyldimethoxy Silane, benzyldimethylmethoxysilane, benzyldimethoxysilane, benzyldiethoxysilane, benzylmethyldiethoxysilane, benzyldimethylethoxysilane, benzyltriethoxysilane, dibenzyldimethoxysilane, dibenzyldiethoxysilane, 3-acetoxypropyltrimethoxysilane 3-acryloxypropyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane 4-aminobutyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-amino Propyltrimethoxysilane, 6- (aminohexylaminopropyl) trimethoxysilane, p-aminophenyltrimethoxysilane, p-aminophenylethoxysilane, m-aminophenyltrimethoxysilane, m-aminophenylethoxysilane, 3-amino Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, ω-aminoundecyltrimethoxysilane, amyltriethoxysilane, benzoxacilepin dimethyl ester, 5- (bicycloheptenyl) triethoxysilane, bis (2 Hydroxyethyl) -3-aminopropyltriethoxysilane, 8-bromooctyltrimethoxysilane, bromophenyltrimethoxysilane, 3-bromopropyltrimethoxysilane, n-butyltrimethoxysilane, 2-chloromethyltriethoxysilane, chloro Methylmethyldiethoxysilane, chloromethylmethyldiisopropoxysilane, p- (chloromethyl) phenyltrimethoxysilane, chloromethyltriethoxysilane, chlorophenyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltriethoxy Silane, 3-chloropropyltrimethoxysilane, 2- (4-chlorosulfonylphenyl) ethyltrimethoxysilane, 2-cyanoethyltriethoxysilane, 2-cyanoethyltrimethyl Xysilane, cyanomethylphenethyltriethoxysilane, 3-cyanopropyltriethoxysilane, 2- (3-cyclohexenyl) ethyltrimethoxysilane, 2- (3-cyclohexenyl) ethyltriethoxysilane, 3-cyclohexenyltrichlorosilane, 2- (3-Cyclohexenyl) ethyltrichlorosilane, 2- (3-cyclohexenyl) ethyldimethylchlorosilane, 2- (3-cyclohexenyl) ethylmethyldichlorosilane, cyclohexyldimethylchlorosilane, cyclohexylethyldimethoxysilane, cyclohexyl Methyldichlorosilane, cyclohexylmethyldimethoxysilane, (cyclohexylmethyl) trichlorosilane, cyclohexyltrichlorosilane, cyclohexyltrimethoxysilane, Looctyltrichlorosilane, (4-cyclooctenyl) trichlorosilane, cyclopentyltrichlorosilane, cyclopentyltrimethoxysilane, 1,1-diethoxy-1-silacyclopent-3-ene, 3- (2,4-dinitrophenylamino) propyl Triethoxysilane, (dimethylchlorosilyl) methyl-7,7-dimethylnorpinane, (cyclohexylaminomethyl) methyldiethoxysilane, (3-cyclopentadienylpropyl) triethoxysilane, N, N-diethyl-3- Aminopropyl) trimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, (furfuryloxymethyl) triethoxysilane, 2-hydroxy -4- (3-triethoxypropoxy) diphenyl ketone, 3- (p-methoxyphenyl) propylmethyldichlorosilane, 3- (p-methoxyphenyl) propyltrichlorosilane, p- (methylphenethyl) methyldichlorosilane, p- (Methylphenethyl) trichlorosilane, p- (methylphenethyl) dimethylchlorosilane, 3-morpholinopropyltrimethoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 1, 2,3,4,7,7-hexachloro-6-methyldiethoxysilyl-2-norbornene, 1,2,3,4,7,7-hexachloro-6-triethoxysilyl-2-norbornene, 3, -Iodopropyltrimethoxylane, 3-isocyanate pro Pyrtriethoxysilane, (mercaptomethyl) methyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryl Roxypropyltrimethoxysilane, methyl {2- (3-trimethoxysilylpropylamino) ethylamino} -3-propionate, 7-octenyltrimethoxysilane, RN-α-phenethyl-N′-triethoxysilylpropyl Urea, S-N-α-phenethyl-N′-triethoxysilylpropylurea, phenethyltrimethoxysilane, phenethylmethyldimethoxysilane, phenethyldimethylmethoxysilane, phenethyldimethoxysilane, fluorine Netyldiethoxysilane, phenethylmethyldiethoxysilane, phenethyldimethylethoxysilane, phenethyltriethoxysilane, (3-phenylpropyl) dimethylchlorosilane, (3-phenylpropyl) methyldichlorosilane, N-phenylaminopropyltrimethoxysilane, N -(Triethoxysilylpropyl) dansilamide, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, 2- (triethoxysilylethyl) -5- (chloroacetoxy) bicycloheptane, (S)- N-triethoxysilylpropyl-O-ment carbamate, 3- (triethoxysilylpropyl) -p-nitrobenzamide, 3- (triethoxysilyl) propyl succinic anhydride, N- [5- (trimethoxysilyl) -2-Aza-1-oxo-pentyl] caprolactam, 2- (trimethoxysilylethyl) pyridine, N- (trimethoxysilylethyl) benzyl-N, N, N-trimethylammonium chloride, phenylvinyldiethoxysilane, 3 -Thiocyanatopropyltriethoxysilane, N- {3- (triethoxysilyl) propyl} phthalamic acid, 1-trimethoxysilyl-2- (chloromethyl) phenylethane, 2- (trimethoxysilyl) ethylphenylsulfonyl azide , Β-trimethoxysilylethyl-2-pyridine, trimethoxysilylpropyldiethylenetriamine, N- (3-trimethoxysilylpropyl) pyrrole, N-trimethoxysilylpropyl-N, N, N-tributylammonium bromide, N-trimethoxy Silylpropyl-N, N, N-tributylammonium chloride, N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride, vinylmethyldiethoxylane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane , Vinyldimethylmethoxysilane, vinyldimethylethoxysilane, vinylmethyldichlorosilane, vinylphenyldichlorosilane, vinylphenyldiethoxysilane, vinylphenyldimethylsilane, vinylphenylmethylchlorosilane, vinyltriphenoxysilane, vinyltris-t-butoxysilane, adamantyl Ethyltrichlorosilane, allylphenyltrichlorosilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, 3-aminosilane Noxydimethylvinylsilane, phenyltrichlorosilane, phenyldimethylchlorosilane, phenylmethyldichlorosilane, benzyltrichlorosilane, benzyldimethylchlorosilane, benzylmethyldichlorosilane, phenethyldiisopropylchlorosilane, phenethyltrichlorosilane, phenethyldimethylchlorosilane, phenethylmethyldichlorosilane, 5- (Bicycloheptenyl) trichlorosilane, 5- (bicycloheptenyl) triethoxysilane, 2- (bicycloheptyl) dimethylchlorosilane, 2- (bicycloheptyl) trichlorosilane, 1,4-bis (trimethoxysilylethyl) benzene, Bromophenyltrichlorosilane, 3-phenoxypropyldimethylchlorosilane, 3-phenoxypropyltrichloro Lan, t-butylphenylchlorosilane, t-butylphenylmethoxysilane, t-butylphenyldichlorosilane, p- (t-butyl) phenethyldimethylchlorosilane, p- (t-butyl) phenethyltrichlorosilane, 1,3- (chloro Dimethylsilylmethyl) heptacosane, ((chloromethyl) phenylethyl) dimethylchlorosilane, ((chloromethyl) phenylethyl) methyldichlorosilane, ((chloromethyl) phenylethyl) trichlorosilane, ((chloromethyl) phenylethyl) trimethoxy Silane, chlorophenyltrichlorosilane, 2-cyanoethyltrichlorosilane, 2-cyanoethylmethyldichlorosilane, 3-cyanopropylmethyldiethoxysilane, 3-cyanopropylmethyldichlorosilane, 3-sia Propyl methyl dichlorosilane, 3-cyanopropyl dimethyl ethoxy silane, 3-cyanopropyl methyl dichlorosilane, can be mentioned 3-cyanopropyl trichloro silane.

(Phosphate ester)
As phosphate ester, what has a chemical structure obtained, for example by dehydration condensation of phosphoric acid and alcohol can be used. Specific examples of such a compound include lauryl phosphate, lauryl-2 phosphate, steareth-2 phosphate, 2- (perfluorohexyl) ethylphosphonic acid, and the like.

(carboxylic acid)
As the carboxylic acid, a compound (fatty acid) having a hydrocarbon group and a carboxyl group can be used. Specific examples of such compounds include decanoic acid, tetradecanoic acid, octadecanoic acid, cis-9-octadecenoic acid and the like.
The first ink is cured by irradiation with ultraviolet rays as described above. However, if the metal particles are contained in such ink, the metal particles function as a catalyst for the curing reaction. The present inventor has found that the ink storage gel and the ejection stability are hindered by causing gelation of the ink without causing irradiation and causing problems such as an increase in viscosity. On the other hand, the occurrence of such a problem can be reliably prevented by forming the coating as described above on the surface of the metal particles. That is, in the first particles having a coating film formed on the surface, the coating prevents the metal particles from contacting the polymerizable compound in the ink and suppresses the ink reaction. As a result, a first ink excellent in storage stability and ejection stability can be obtained.

  In addition, the film formed on the surface of the metal particles preferably contains a fluorine compound containing at least one fluorine atom in the molecule. By using the fluorine-based compound, sufficient liquid repellency is imparted to the surface of the first particle, and the surface tension of the first particle can be surely made smaller than that of the second particle. Therefore, in the printing part manufactured using the first ink, it is possible to more effectively exhibit characteristics such as glossiness inherent in the metal material. Then, by using the first particles provided with a coating containing a fluorine compound, the first ink is manufactured even when the first ink contains a polymerizable compound having a large surface tension. In the recorded matter, the first particles can be reliably arranged (leafed) in the vicinity of the outer surface of the printing portion. For this reason, the selection range of the polymerizable compound is widened, and the characteristics of the first ink and the recorded matter manufactured using the first ink can be obtained without sacrificing the glossiness of the metal material. The characteristics (for example, the viscosity of the first ink, the storage stability, the ejection stability, the abrasion resistance of the recorded matter, etc.) can be easily adjusted.

In addition, the coating film containing the fluorine-based compound is sufficiently excellent in the chemical stability and dispersion stability of the first particles in the first ink, and the storage stability of the first ink and the ejection over a long period of time. Stability can be made sufficiently excellent.
In addition, the fluorine compound preferably has a perfluoroalkyl structure. As a result, the storage stability of the first ink can be further improved, and the glossiness and rub resistance of the printed portion produced using the first ink can be further improved.

  Moreover, as said fluorine-type compound, what contains at least 1 fluorine atom in a molecule | numerator should just be mentioned, More specifically, for example, the above-mentioned silane coupling agent, phosphate ester, carboxylic acid, etc. And compounds having a structure in which at least some of the hydrogen atoms are substituted with fluorine atoms (fluorine silane compounds, fluorine phosphates, fluorine-substituted fatty acids, etc.). By using these compounds, the effects as described above are more remarkably exhibited.

In particular, the fluorine-based silane compound preferably has a chemical structure represented by the following formula (A).
R ¹ SiX ¹ _a R ² _(3-a) (A)
(In formula (A), R ¹ represents a hydrocarbon group in which part or all of the hydrogen atoms are substituted with fluorine atoms, X ¹ represents a hydrolyzable group, an ether group, a chloro group or a hydroxyl group; ² represents an alkyl group having 1 to 4 carbon atoms, and a is an integer of 1 to 3 inclusive.)
As a result, the storage stability of the first ink can be made particularly excellent, and the glossiness and abrasion resistance of the printed part produced using the first ink can be made particularly excellent.

Examples of R ¹ in the formula (A) include an alkyl group, an alkenyl group, an aryl group, an aralkyl group and the like in which part or all of the hydrogen atoms are substituted with fluorine atoms, and are further included in the molecular structure. At least a part of hydrogen atoms (hydrogen atoms not substituted with fluorine atoms) may be substituted with an amino group, a carboxyl group, a hydroxyl group, a thiol group, etc., and -O-, -S in the carbon chain A hetero atom such as-, -NH-, -N =, or an aromatic ring such as benzene may be sandwiched. Specific examples of R ¹ include, for example, a phenyl group, a benzyl group, a phenethyl group, a hydroxyphenyl group, a chlorophenyl group, an aminophenyl group, a naphthyl group, an anthrenyl group in which part or all of the hydrogen atoms are substituted with fluorine atoms, Pyrenyl group, thienyl group, pyrrolyl group, cyclohexyl group, cyclohexenyl group, cyclopentyl group, cyclopentenyl group, pyridinyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec- Butyl group, tert-butyl group, octadecyl group, n-octyl group, chloromethyl group, methoxyethyl group, hydroxyethyl group, aminoethyl group, cyano group, mercaptopropyl group, vinyl group, allyl group, acryloxyethyl group, Methacryloxyethyl group, glycidoxypropyl Group, acetoxy group and the like.

Specific examples of the fluorine-based silane compound represented by the formula (A) have a structure in which some or all of the hydrogen atoms included in the compound exemplified as the silane compound having a silyl group and a hydrocarbon group are substituted with fluorine atoms. A compound can be mentioned.
The fluorine-based silane compound having a perfluoroalkyl structure _{(C n F 2n + 1)} , for example, those represented by the following formula (B).
_{C n F 2n + 1 (CH} 2) m SiX 1 a R 2 (3-a) (B)
(In the formula (B), X ¹ represents a hydrolyzable group, an ether group, a chloro group or a hydroxyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 14) M is an integer of 2 to 6, and a is an integer of 1 to 3.

Specific examples of the compound having such a structure include CF ₃ —CH ₂ CH ₂ —Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₃ —CH ₂ CH ₂ —Si (OCH ₃ ) ₃ , CF _3. (CF ₂ ) ₅ —CH ₂ CH ₂ —Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₅ —CH ₂ CH ₂ —Si (OC ₂ H ₅ ) ₃ , CF ₃ (CF ₂ ) ₇ —CH _{2 CH 2 -Si (OCH 3) 3} , CF 3 (CF 2) 11 -CH 2 CH 2 -Si (OC 2 H 5) 3, CF 3 (CF 2) 3 -CH 2 CH 2 -Si (CH 3) _{(OCH 3) 2, CF 3} (CF 2) 7 -CH 2 CH 2 -Si (CH 3) (OCH 3) 2, CF 3 (CF 2) 8 -CH 2 CH 2 -Si (CH 3) (OC _{2 H 5) 2, CF 3} (CF 2) _{8 -CH 2 CH 2 -Si (C} 2 H 5) (OC 2 H 5) 2 and the like.

Further, as the fluorine-based silane compound may be used those having a perfluoroalkyl ether structure _{(C n F 2n + 1 O} ) in place of the above-mentioned perfluoroalkyl structure _{(C n F 2n + 1)} .
The fluorine-based silane compound having a perfluoroalkyl ether structure _{(C n F 2n + 1 O} ), for example, those represented by the following formula (C).

_{C p F 2p + 1 O (} C p F 2p O) r (CH 2) m SiX 1 a R 2 (3-a) (C)
(In formula (C), X ¹ represents a hydrolyzable group, ether group, chloro group or hydroxyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, and p is an integer of 1 to 4 inclusive. Yes, r is an integer from 1 to 10, m is an integer from 2 to 6, and a is an integer from 1 to 3.

Specific examples of the compound having such a structure include CF ₃ O (CF ₂ O) ₆ —CH ₂ CH ₂ —Si (OC ₂ H ₅ ) ₃ , CF ₃ O (C ₃ F ₆ O) ₄ —CH. ₂ CH ₂ —Si (OCH ₃ ) ₃ , CF ₃ O (C ₃ F ₆ O) ₂ (CF ₂ O) ₃ —CH ₂ CH ₂ —Si (OCH ₃ ) ₃ , CF ₃ O (C ₃ F ₆ O _{) 8 -CH 2 CH 2 -Si (} OCH 3) 3, CF 3 O (C 4 F 9 O) 5 -CH 2 CH 2 -Si (OCH 3) 3, CF 3 O (C 4 F 9 O) 5 _{-CH 2 CH 2 -Si (CH 3} ) (OC 2 H 5) 2, CF 3 O (C 3 F 6 O) 4 -CH 2 CH 2 -Si (C 2 H 5) (OCH 3) 2 and the like Can be mentioned.

Further, the fluorine-based phosphate ester preferably has a chemical structure represented by the following formula (D).
POR _n (OH) _3-n (D)
(In the formula (D), R _{is, CF 3 (CF 2) m} -, CF 3 (CF 2) m (CH 2) l -, CF 3 (CF 2) m (CH 2 O) l -, CF 3 (CF ₂ ) _m O— or CF ₃ (CF ₂ ) _m (CH ₂ ) ₁ O—, n is an integer of 1 to 3, m is an integer of 4 to 20, Is an integer from 4 to 20.)

As a result, the storage stability of the first ink can be made particularly excellent, and the glossiness and abrasion resistance of the printed part produced using the first ink can be made particularly excellent.
In formula (D), m is preferably an integer of 4 or more and 16 or less. Thereby, the effects as described above are more remarkably exhibited.
In the formula (D), l is preferably an integer of 4 or more and 16 or less. Thereby, the effects as described above are more remarkably exhibited.

<Polymerizable compound>
The first ink contains a polymerizable compound that is a component that is polymerized and cured by irradiation with ultraviolet rays. By including such components, it is possible to improve the abrasion resistance, water resistance, solvent resistance, and the like of the recorded matter produced using the ink set. The polymerizable compound is in a liquid form, and preferably functions as a dispersion medium for dispersing the first particles in the first ink. As a result, it is not necessary to use a dispersion medium that is removed (evaporated) separately in the production process of the recorded material, and it is not necessary to provide a process for removing the dispersion medium in the production of the recorded material. The property can be made particularly excellent. Moreover, since it is not necessary to use what is generally used as an organic solvent as a dispersion medium, generation | occurrence | production of the problem of a volatile organic compound (VOC) can be prevented. Moreover, by including a polymerizable compound, it is possible to improve the adhesiveness of a printing portion formed using an ink set with respect to various recording media (base materials). That is, the inclusion of the polymerizable compound makes the first ink excellent in media compatibility.

  The polymerizable compound may be any component that can be polymerized by irradiation with ultraviolet rays. For example, various monomers and various oligomers (including dimers and trimers) can be used. The first ink is a polymerizable compound. It is preferable that at least a monomer component is included. Since the monomer is generally a component having a low viscosity as compared with the oligomer component or the like, it is advantageous for making the discharge stability of the first ink particularly excellent.

  Examples of the monomer as the polymerizable compound include isobornyl acrylate, 4-hydroxybutyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, phenoxyethyl acrylate, isooctyl acrylate, stearyl acrylate, cyclohexyl acrylate, 2-ethoxyethyl acrylate, Benzyl acrylate, 1H, 1H, 5H-octafluoropentyl acrylate, 1H, 1H, 5H-octafluoropentyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobutyl acrylate, t-butyl acrylate, tetrahydrofurfuryl acrylate , Ethyl carbitol acrylate, 2,2,2-trifluoroethyl acrylate, 2, , 2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl acrylate, methoxytriethylene glycol acrylate, methoxytriethylene glycol acrylate, PO-modified nonylphenol acrylate, EO-modified nonylphenol acrylate, EO-modified 2-ethylhexyl acrylate, EO modified nonylphenol acrylate, phenyl glycidyl ether acrylate, phenoxydiethylene glycol acrylate, EO modified phenol acrylate, phenoxyethyl acrylate, EO modified phenol acrylate, EO modified cresol acrylate, methoxy polyethylene glycol acrylate, dipropylene glycol acrylate, dicyclopentenyl acrylate, dicyclo Tertenyloxyethyl acrylate, 2-n-butyl-2-ethyl-1,3-propanediol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, 1.9-nonanediol diacrylate, 1,4- Butanediol diacrylate, bisphenol A EO modified diacrylate, 1.6-hexanediol diacrylate, polyethylene glycol 200 diacrylate, polyethylene glycol 300 diacrylate, neopentyl glycol hydroxypiparate diacrylate, 2-ethyl-2-butyl- Propanediol diacrylate, polyethylene glycol 400 diacrylate, polyethylene glycol 600 diacrylate, polypropylene glycol diacrylate 1.9-nonanediol diacrylate, 1.6-hexanediol diacrylate, bisphenol A EO modified diacrylate, bisphenol A EO modified diacrylate, bisphenol A EO modified diacrylate, PO modified bisphenol A diacrylate, EO modified water Bisphenol A diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane EO-modified triacrylate, glycerin PO-added triacrylate, trisacryloyloxyethyl phosphate, penta Erythritol tetraacrylate, PO-modified trimethylolpropane triacrylate, P Modified trimethylolpropane triacrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, acrylic acid 2- (2-vinyloxy ethoxy) ethyl and the like. Among them, 4-hydroxybutyl acrylate, phenoxyethyl acrylate, phenoxyethyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, trimethylolpropane tri Preferred are acrylate, trimethylolpropane EO-modified triacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, and 2- (2-vinyloxyethoxy) ethyl acrylate.

  In particular, the first ink preferably contains phenoxyethyl acrylate as the polymerizable compound. As a result, the storage stability of the first ink is excellent, the reactivity of the first ink after ejection by the ink jet method is particularly excellent, and the productivity of recorded matter is particularly excellent. In addition, the printed portion to be formed can have particularly excellent abrasion resistance and the like.

  In addition to the phenoxyethyl acrylate, the first ink includes 2- (2-vinyloxyethoxy) ethyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and 4-hydroxybutyl as a polymerizable compound. It is preferable that it contains at least one selected from the group consisting of acrylates. Accordingly, the storage stability of the first ink is particularly excellent, the reactivity of the first ink after ejection by the ink jet method is particularly excellent, and the productivity of the recorded matter is particularly excellent. In addition, it is possible to further improve the abrasion resistance and the like of the printed portion to be formed.

Further, the first ink may contain an oligomer as the polymerizable compound in addition to the monomer. In particular, those containing polyfunctional oligomers are preferred. As a result, the storage stability of the first ink can be made excellent, and the abrasion resistance and the like of the printed portion to be formed can be made particularly excellent. In the present invention, among polymerizable compounds, those having a repeating structure in the molecular skeleton and having a molecular weight of 600 or more are called oligomers. As the oligomer, a urethane oligomer whose repeating structure is urethane, an epoxy oligomer whose repeating structure is epoxy, and the like are preferably used.
The first ink preferably contains at least one of dimethylol tricyclodecane diacrylate and amino acrylate as the polymerizable compound. As a result, the storage stability of the first ink can be further improved, and the abrasion resistance and the like of the printed portion to be formed can be further improved.

<Other ingredients>
The first ink may contain components other than those described above (other components). Such components include, for example, photopolymerization initiators, slip agents (leveling agents), dispersants, polymerization accelerators, polymerization inhibitors, penetration enhancers, wetting agents (humectants), colorants, fixing agents, anti-blocking agents. Examples include glazes, preservatives, antioxidants, chelating agents, thickeners, and sensitizers (sensitizing dyes).

  The photopolymerization initiator is not particularly limited as long as it generates active species such as radicals and cations by ultraviolet irradiation and initiates the polymerization reaction of the polymerizable compound. As the photopolymerization initiator, a radical photopolymerization initiator or a cationic photopolymerization initiator can be used, but it is preferable to use a radical photopolymerization initiator. When using a photopolymerization initiator, the photopolymerization initiator preferably has an absorption peak in the ultraviolet region.

Examples of the photo radical polymerization initiator include aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, Examples thereof include ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.
Among these, at least one selected from an acylphosphine oxide compound and a thioxanthone compound is preferable from the viewpoint of solubility in a polymerizable compound and curability, and it is more preferable to use an acylphosphine oxide compound and a thioxanthone compound in combination.

  Specific examples of the photo radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine. , Carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) ) -2-Hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethyl Oxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenyl Phosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, etc. 1 type or 2 types or more selected from these can be used in combination.

The content of the photopolymerization initiator in the first ink is preferably 0.5% by mass or more and 10% by mass or less. When the content of the photopolymerization initiator is within the above range, the ultraviolet curing rate is sufficiently high, and the undissolved portion of the photopolymerization initiator and the color derived from the photopolymerization initiator are almost eliminated.
When the first ink contains a slip agent, the surface of the recorded matter becomes smooth due to the leveling action, and the abrasion resistance is improved.

Although it does not specifically limit as a slip agent, For example, silicone type surfactants, such as polyester modified silicone and polyether modified silicone, can be used, It is preferable to use polyether modified polydimethylsiloxane or polyester modified polydimethylsiloxane. .
When the first ink contains a dispersant, the dispersibility of the metal powder can be made excellent, and the storage stability and ejection stability of the first ink can be made particularly excellent. The dispersant is not particularly limited, and examples thereof include polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, and sulfur-containing polymers. , Fluorine-containing polymers, epoxy resins and the like.

The first ink preferably does not contain an organic solvent that is removed (evaporated) in the manufacturing process of the recorded matter. Thereby, generation | occurrence | production of the problem of a volatile organic compound (VOC) can be prevented effectively.
The viscosity of the first ink at room temperature (20 ° C.) is preferably 20 mPa · s or less, and more preferably 3 mPa · s or more and 15 mPa · s or less. Thereby, the droplet discharge by an inkjet method can be performed suitably.

«Second ink»
The second ink as an ultraviolet curable inkjet ink constituting the ink set of the present invention is ejected by an inkjet method, and includes second particles and a polymerizable compound that is polymerized by irradiation with ultraviolet rays. It is a waste.
<Second particle>
As described above, the second ink constituting the ink set of the present invention includes a large number of second particles having a surface tension larger than that of the first particles.
When the second ink including the second particles having a surface tension larger than that of the first particles is discharged together with the first ink including the first particles, the first particles are relatively While arranged on the surface side of the discharged material based on a small surface tension, the second particles are dispersed more inside the discharged material than the first particles based on a relatively large surface tension.

  Here, if the second particles are not included, only the first particles are present in the discharged material, and therefore the first particles are arranged on the surface side of the discharged material. In this case, the surface of the ejected matter is covered with the first particles, and even if ultraviolet rays are irradiated to cure the ejected matter, the ultraviolet rays hardly reach the inside of the ejected matter. For this reason, there was a problem that it was difficult for the curing to proceed inside the discharged material. On the other hand, in order to suppress unevenness in the recorded material and to generate a certain amount of glossiness peculiar to metal, it is necessary to contain a sufficient proportion of the first particles in the first ink. Therefore, in the case where the second particles are not included, it is impossible to make compatible properties such as curability of the ejected material and glossiness in the recorded material.

  On the other hand, by using the second ink containing the second particles, the proportion of the first particles in the first ink can be lowered by the amount of the second particles. Even if the ratio of the first particles is lowered, since the second particles are contained, the glossiness or the like is not significantly reduced. As described above, since the second particles are dispersed on the inner side of the first particles, the ultraviolet rays easily reach the inside of the discharged material, and the curability of the discharged material can be ensured. And when the second particles have light reflectivity based on their constituent materials and particle shapes, if they are dispersed inside the discharge material, the ultraviolet rays are scattered over the entire discharge material. The curability of the product is particularly improved. Therefore, according to the ink set of the present invention, the excellent curability of the discharged product and the excellent glossiness of the recorded material can be highly compatible. As a result, it is possible to reliably form a recorded matter having high definition and excellent glossiness peculiar to a metal by ejecting droplets by an ink jet method.

Here, the surface tension of the first particle or the second particle is an interfacial tension generated at the interface with air among the interfacial tension of the surface of each particle. The surface tension can be measured by, for example, a wettability test method defined in JIS R 3257, and mN / m is used as a unit.
As described above, the surface tension of the second particles may be larger than the surface tension of the first particles, but the difference is preferably 5 mN / m or more, and is 7 mN / m or more and 40 mN / m or less. More preferably, it is 10 mN / m or more and 30 mN / m or less. By setting the difference in surface tension within the above range, when the second ink containing the second particles is ejected, the second particles are dispersed inside without being arranged on the surface of the ejected matter, and the ejected matter As a result, the transmittance of ultraviolet rays in the inside of the inside is reliably increased. When the difference in surface tension is smaller than the lower limit value, the second particles are likely to be arranged on the surface in the same manner as the first particles, and the curability of the discharged material may be reduced. When the difference is larger than the lower limit value, the surface tension of the second particles becomes relatively large, and the second particles may easily settle. In this case, the glossiness of the recorded matter may be impaired.

The shape of the second particles, the particle size, the content in the second ink, the production method, the viscosity of the second ink, and the like are the same as those of the first particles or the first ink.
Among these, the shape of the second particles is particularly preferably a scaly shape. As a result, even if the second particles are not arranged on the surface of the ejected matter and dispersed therein, a recorded matter exhibiting a sufficient glossiness can be obtained when it is cured. For this reason, the curability of the discharged material and the glossiness of the recorded material can be made highly compatible.

In addition, as the constituent material of the second particles, the same constituent material as that of the first particles described above is used. In particular, a material mainly composed of aluminum is preferably used. By using the second particles mainly composed of aluminum, it is possible to particularly enhance the glossiness in the recorded matter.
The constituent material of the second particles is preferably the same composition as the constituent material of the first particles. As a result, if the particle sizes are approximately the same, the mass of the second particles is approximately the same as the mass of the first particles, and it becomes easier to control the particle behavior in the discharge according to the surface condition. For this reason, by appropriately setting the presence / absence and type of the surface treatment, it becomes easy to achieve both the curability of the discharged material and the glossiness of the recorded material.

The second particles may be metal particles composed only of the above-described metal material, but may be those subjected to various surface treatments.
Examples of the surface treatment applied to the second particles include a treatment for making the surface tension larger than that of the first particles. Specifically, surface modification treatment for modifying the surface of the metal particles, film formation treatment for forming a film on the surface of the metal particles, and the like can be mentioned. Thereby, even if the composition of the metal particles is the same, the first particles and the second particles can be produced only by changing the kind of the surface treatment, so that the behavior of the particles can be controlled finely. Is useful.

Among these, examples of the constituent material of the film formed on the surface of the metal particles include a coupling agent, a phosphate ester compound, and a carboxylic acid compound. Each of these materials is the same as that used in the surface treatment applied to the first particles.
Further, as described above, the second ink is cured by the irradiation of ultraviolet rays. However, like the first ink, when the ink contains metal particles, the metal particles function as a catalyst for the curing reaction. For this reason, the ink is gelled without irradiating with ultraviolet rays, causing problems such as an increase in viscosity, thereby impairing the storage stability and ejection stability of the ink. On the other hand, the occurrence of such a problem can be reliably prevented by forming the coating as described above on the surface of the metal particles. That is, in the second particles having a film formed on the surface, the coating prevents the metal particles from contacting the polymerizable compound in the ink and suppresses the reaction of the ink. As a result, a second ink excellent in storage stability and ejection stability can be obtained.

  Here, the coating film formed on the surface of the second particle preferably contains a phosphate ester compound. By using a phosphoric ester compound, appropriate liquid repellency is imparted to the surface of the second particle, and the surface of the second particle has a surface tension larger than that of the first particle. These particles are surely dispersed in the discharged material. In particular, when the coating film formed on the surface of the first particle contains a fluorine compound, the second particle having a coating containing a phosphate ester compound has a range as described above with respect to the first particle. It has a surface tension difference, and the effect of the present invention becomes more remarkable.

As the phosphoric ester compound, those having any structure can be used as long as they are esters obtained by dehydration condensation of phosphoric acid and alcohol. Specifically, the hydrogen atom in phosphoric acid represented by O = P (OH) ₃ has a structure in which all or part of the hydrogen atoms are substituted with an organic group. When the surface of the metal particle reacts with the phosphate ester compound, the double bond is cleaved in this structure, and the surface of the metal particle and the phosphorus atom are covalently bonded via an oxygen atom. As a result, the phosphate ester compound can form a strong film formed on the surface of the metal particles.

In addition, in the present invention, the phosphate ester-based compound refers to a compound including only a salt thereof, and a compound including both of them, in addition to a compound having only the above structure.
Examples of such phosphate ester compounds include polyoxyethylene alkyl ether phosphates or salts thereof, fatty acid glyceride phosphates or salts thereof, and the like. With such a phosphoric ester compound, the above-described effects become more remarkable.
Among these, the monoester body of polyoxyethylene alkyl ether phosphate is represented by the following general formula (1).

［式中、Ｒ^３はアルキル基、アルキレン基またはフェニル基であり、ｎは２〜１０の整数である。］

[Wherein R ³ represents an alkyl group, an alkylene group or a phenyl group, and n represents an integer of 2 to 10. ]

  Moreover, the diester body of polyoxyethylene alkyl ether phosphate is represented by following General formula (2).

［式中、Ｒ^３はアルキル基、アルキレン基またはフェニル基であり、ｎは２〜１０の整数である。］

[Wherein R ³ represents an alkyl group, an alkylene group or a phenyl group, and n represents an integer of 2 to 10. ]

Here, the general formula (1) and general formula (2), the number of carbon atoms in the alkyl group R ³ is preferably from 8 to 18, and more preferably 12.
Examples of such polyoxyethylene alkyl ether phosphate esters include NIKKOL DDP-2, DDP-4, DDP-6, DDP-10, TLP-4, TCP-5, TDP-2, TDP-6, and TDP. -8, TDP-10 (manufactured by Nikko Chemicals Co., Ltd.), Prisurf AL, A210D, A-208B, A219B (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Adeka Coal CS-1361E (manufactured by ADEKA) And Phosphanol RD-720 (manufactured by Toho Chemical Industry Co., Ltd.).

Moreover, as a salt of polyoxyethylene alkyl ether phosphate ester, sodium salt, potassium salt, monoethanolamine salt of polyoxyethylene alkyl ether phosphate ester represented by the above general formula (1) and general formula (2) Etc.
Examples of such salts of polyoxyethylene alkyl ether phosphate esters include NIKKOL DLP-10, DOP-8NV (above, manufactured by Nikko Chemicals), Prisurf M-208F, M-208B (above, No. 1). Ichi Kogyo Seiyaku Co., Ltd.).

On the other hand, fatty acid glycerides in fatty acid glyceride phosphate esters are monoglycerides, diglycerides, and triglycerides of various fatty acids such as palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, ricinoleic acid, and dihydroxy acid. Of these, phosphate esters of unsaturated fatty acid triglycerides are preferably used, and phosphate esters of triglyceride of ricinoleic acid are more preferably used. Since the fatty acid triglyceride has a bulky and elongated molecular structure, the interaction between molecules works strongly. For this reason, the fatty acid triglyceride phosphate is bonded to the surface of the metal particles, whereby a uniform and dense film is formed. As a result, the contact frequency between the surface of the metal particles and the polymerizable compound is suppressed, and the function of the metal particles as a catalyst is suppressed. As a result, gelation of the photocurable ink can be suppressed. In addition, since ricinoleic acid has a long molecular chain, the intermolecular interaction works more remarkably.
The monoester body of fatty acid glyceride phosphate ester is represented by the following general formula (3).

［式中、Ｒ^４はリン酸とエステルを形成している脂肪酸グリセリドの残基である。］

[Wherein R ⁴ is a residue of a fatty acid glyceride forming an ester with phosphoric acid. ]

  Moreover, the diester body of fatty acid glyceride phosphate is represented by the following general formula (4).

［式中、Ｒ^４はリン酸とエステルを形成している脂肪酸グリセリドの残基である。］

[Wherein R ⁴ is a residue of a fatty acid glyceride forming an ester with phosphoric acid. ]

  In addition, the following chemical formula (5) shows an example of a fatty acid glyceride (ricinoleic acid triglyceride).

  Such a fatty acid glyceride phosphate ester is obtained by, for example, reacting a fatty acid glyceride with phosphorus oxyhalide and then hydrolyzing, or by reacting phosphate with phosphorus oxyhalide to form a pyrophosphate ester, It is produced by a method of decomposing, a method of reacting an aliphatic glyceride and a phosphorous oxide, etc. Among them, a method of reacting an aliphatic glyceride and a phosphorous oxide is preferably used. Phosphorus is preferably used. In this case, it is preferable to react diphosphorus pentoxide at a ratio of 0.2 mol to 1 mol with respect to 1 mol of the aliphatic glyceride. Moreover, when making it react, it is preferable to heat for 10 minutes or more and 300 minutes or less at the temperature of 40 to 120 degreeC, stirring the mixture of an aliphatic glyceride and a phosphoric acid oxide.

Examples of the salt of the aliphatic glyceride phosphate ester include alkali metal salts, alkaline earth metal salts, amine salts and the like of the aliphatic glyceride phosphate esters represented by the above general formula (3) and general formula (4). It is done.
Such a salt of an aliphatic glyceride phosphate is produced, for example, by a method of reacting an aliphatic glyceride phosphate with an overbased sulfonate metal salt. As an example, when producing an alkali metal salt of an aliphatic glyceride phosphate, an alkali metal salt of an overbased sulfonate is used.

<Polymerizable compound>
Similar to the first ink, the second ink contains a polymerizable compound that is a component that polymerizes and cures when irradiated with ultraviolet rays. The polymerizable compound contained in the second ink is the same as the polymerizable compound contained in the first ink.
The polymerizable compound contained in the second ink preferably has the same composition as the polymerizable compound contained in the first ink. Accordingly, when the first ink and the second ink are ejected to the same position on the recording medium, the first ink and the second ink are easily mixed. As a result, since the first particles and the second particles exhibit different behaviors, it is possible to more surely achieve the effect of achieving both the curability of the discharged material and the glossiness of the recorded material.

<Other ingredients>
The second ink may contain other components similar to those contained in the first ink described above.
≪Other inks≫
The ink set of the present invention only needs to include the first ink and the second ink described above, but may further include other inks in addition to these.

  Examples of such an ink include an ink (chromatic color ink) that can be used alone for forming a chromatic color printing portion, and a colorless ink (clear ink) that does not contain a colorant and metal powder. In particular, the colorless ink is particularly excellent in the durability (rubbing resistance, etc.) of the printed part by being applied, for example, on the portion of the recording medium to which the first ink and the second ink described above are applied. In addition, the adhesiveness of each ink to the recording medium can be further improved by providing the recording medium in advance.

[Recordings]
Next, recorded matter formed using the ink set of the present invention will be described.
This recorded matter is manufactured by applying the first ink and the second ink onto a recording medium by an inkjet method and irradiating with ultraviolet rays. Such a recorded matter has a high definition and a glossiness peculiar to metal.

  As described above, the first ink and the second ink constituting the ink set of the present invention each contain a polymerizable compound and have excellent adhesion to the recording medium. For this reason, the printing part formed with these inks can be excellent in adhesion to the recording medium. Accordingly, the recording medium may be any material, and any of absorptive or nonabsorptive materials may be used. For example, paper (plain paper, ink jet dedicated paper, etc.), plastic material, metal, ceramics, wood Natural fibers / synthetic fibers such as shells, cotton, polyester, and wool, and non-woven fabrics can be used.

  Further, the use of the recorded matter may be anything, and for example, it may be applied to a decorative article or other. Specific examples include console lids, switch bases, center clusters, interior panels, emblems, center consoles, meter nameplates and other vehicle interior parts, various electronic device operation parts (key switches), and decorative parts that exhibit decorative properties. Display items such as indicators and logos.

As a droplet discharge method (inkjet method), a piezo method, a method in which ink is discharged by bubbles generated by heating ink, or the like can be used. From the viewpoint of difficulty, the piezo method is preferable.
The discharge of ink (ink constituting the ink set) by the ink jet method can be performed using a known droplet discharge device.

The first ink and the second ink ejected by the inkjet method are cured by irradiation with ultraviolet rays.
As the ultraviolet light source, for example, a mercury lamp, a metal halide lamp, an ultraviolet light emitting diode (UV-LED), an ultraviolet laser diode (UV-LD), or the like can be used. Among these, ultraviolet light emitting diodes (UV-LED) and ultraviolet laser diodes (UV-LD) are preferable from the viewpoints of small size, long life, high efficiency, and low cost.
The wavelength of the irradiated light is preferably about 200 nm to 450 nm and more preferably about 350 nm to 450 nm. If the wavelength of light is in the above range, each ink can be cured uniformly while sufficiently shortening the curing time.

The irradiation intensity at the irradiation unit is preferably at 10 mW / cm ² or more 2000 mW / cm ² or less, more preferably 20 mW / cm ² or more 1500 mW / cm ² or less. If the irradiation intensity is within the above range, each ink can be cured uniformly and surely without unevenness. The light irradiation is usually started immediately after each ink is ejected. At this time, by reducing the irradiation intensity within the above range, the irradiation time can be increased accordingly. As a result, the time required for the orientation of the metal particles in each discharged ink is secured. As a result, for example, the main surface of the scale-shaped metal particles is oriented along the surface of the recording medium, and the light reflectivity of the pattern (printing portion) can be enhanced. The irradiation time varies depending on the irradiation intensity, but is preferably about 0.1 second to 60 seconds, more preferably about 0.5 seconds to 30 seconds.

Further, the irradiation energy by light irradiation (integrated quantity of light) is preferably at 5 mJ / cm ² or more 1000 mJ / cm ² or less, more preferably 10 mJ / cm ² or more 800 mJ / cm ² or less. When the irradiation energy is within the above range, each ink can be cured uniformly and surely without unevenness.
The first ink and the second ink are preferably ejected at the same position on the recording medium, that is, so that the respective inks overlap. As a result, the first particles and the second particles exhibit different behaviors at the same position, and as a result, the effect that both the curability of the discharged material and the glossiness of the recorded material can be achieved more reliably. it can.

At this time, it is preferable that the first ink and the second ink are ejected so that the content rate of the second particles is larger than the content rate of the first particles in the unit volume of the ejected matter. As a result, it is possible to obtain a recorded material having the minimum curability necessary for ensuring the definition of the recorded material and having the minimum light reflectivity for ensuring the aesthetics of the recorded material. That is, the balance between the curability of the discharged material and the glossiness of the recorded material can be further optimized.
Specifically, the content rate of the second particles is preferably about 1.1 to 4 times the content rate of the first particles, and preferably about 1.3 to 3 times. More preferred.
As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to these.

Next, specific examples of the present invention will be described.
[1] Manufacture of ink set (Example 1)
<Production of first ink>
First, a polyethylene terephthalate film (Made by Mitsubishi Plastics, Diafoil G440E) having a smooth surface was prepared.

Next, silicone oil was applied to the entire one surface of the film.
Next, a film made of Al was formed on the side coated with silicone oil by vapor deposition.
Next, a polyethylene terephthalate film (base material) on which an Al film was formed was placed in a liquid composed of diethylene glycol diethyl ether, and ultrasonic vibration was applied. As a result, scaly Al particles were obtained.

Next, the Al particles obtained as described above were immediately separated by filtration, and the Al particles were added to diethylene glycol diethyl ether so that the solid content was 5% by mass. Thereafter, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane as a fluorine-based silane compound was added to the liquid (dispersion) so as to have a content of 3% by mass. Surface treatment was carried out by stirring at 4 ° C. for 4 hours. Thereby, a dispersion liquid in which Al particles (first particles) surface-treated with a fluorine-based silane compound were dispersed in diethylene glycol diethyl ether was obtained.
The average particle diameter of the first particles thus obtained was 0.8 μm. Moreover, the discharged 1st particle showed the behavior which arranged on the surface of a discharge thing.

  Next, the obtained first particles were mixed with phenoxyethyl acrylate, 2- (2-hydroxyethoxy) ethyl acrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 4-hydroxybutyl acrylate, photopolymerization initiator. Irgacure 819 (manufactured by Ciba Japan), Speedcure TPO (manufactured by Lambson) as a photopolymerization initiator, Speedcure DETX (manufactured by Lambson) as a photopolymerization initiator, UV-3500 (manufactured by Big Chemie) as a leveling agent ) And p-methoxyphenol as a polymerization inhibitor were mixed to obtain an inkjet composition (ultraviolet curable inkjet composition).

<Manufacture of second ink>
First, a film made of polyethylene terephthalate having a smooth surface (surface roughness Ra of 0.02 μm or less) was prepared.
Next, silicone oil was applied to the entire one surface of the film.
Next, a film made of Al was formed on the side coated with silicone oil by vapor deposition.

Next, a polyethylene terephthalate film (base material) on which an Al film was formed was placed in a liquid composed of diethylene glycol diethyl ether, and ultrasonic vibration was applied. As a result, scaly Al particles were obtained.
Next, by putting the particles made of Al obtained as described above into a 0.5 mass% diethylene glycol monobutyl ether acetate solution of ricinoleic acid triglyceride phosphate as a phosphate ester, and stirring for 1 hour, Surface treatment with a phosphate ester was performed to obtain second particles.
The average particle size of the second particles thus obtained was 0.8 μm. Moreover, the discharged 2nd particle showed the behavior which disperse | distributes the inside of a discharged material.

Next, the obtained second particles were mixed with phenoxyethyl acrylate, 2- (2-hydroxyethoxy) ethyl acrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 4-hydroxybutyl acrylate, a photopolymerization initiator. Irgacure 819 (manufactured by Ciba Japan), Speedcure TPO (manufactured by Lambson) as a photopolymerization initiator, Speedcure DETX (manufactured by Lambson) as a photopolymerization initiator, UV-3500 (manufactured by Big Chemie) as a leveling agent ) And p-methoxyphenol as a polymerization inhibitor were mixed to obtain an inkjet composition (ultraviolet curable inkjet composition).
As described above, an ink set composed of two types of inks was obtained.

In addition, the surface tension of the 1st particle | grains processed with the fluorine-type coupling agent was 16 mN / m.
The surface tension of the second particles treated with ricinoleic acid triglyceride phosphate was 15 mN / m greater than the surface tension of the first particles treated with the fluorine-based silane coupling agent.

(Examples 2 to 13)
Ink sets were produced in the same manner as in Example 1 except that the types and ratios of the raw materials used for the preparation of the first ink and the second ink were changed to the compositions shown in the table.
In Example 8, linoleic acid triglyceride phosphate was used as the phosphate of the second particles. The surface tension of the second particles treated with linoleic acid triglyceride phosphate was 25 mN / m greater than the surface tension of the first particles treated with the fluorinated silane coupling agent.

In Example 9, linolenic acid triglyceride phosphate was used as the phosphate of the second particles. The surface tension of the second particles treated with the linolenic acid triglyceride phosphate was 10 mN / m greater than the surface tension of the first particles treated with the fluorine-based silane coupling agent.
In Example 10, oleic acid triglyceride phosphate was used as the phosphate of the second particles. The surface tension of the second particles treated with oleic acid triglyceride phosphate was 30 mN / m greater than the surface tension of the first particles treated with the fluorine-based silane coupling agent.

In addition, CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ O—PO (OH) ₂ was used for the fluorine-based phosphate used in the first particles of Example 11, and the fluorine-based phosphate was used for the treatment. A 1% by mass propanol solution of phosphate ester was used. The surface tension of the second particles treated with ricinoleic acid triglyceride phosphate was 8 mN / m greater than the surface tension of the first particles treated with fluorine-based phosphate.
In Example 12, the first particles having a scaly shape and the second particles having a spherical shape were used.

In Example 13, oleic acid triglyceride phosphate was used as the phosphate of the second particles. Furthermore, CH ₃ (CH ₂ ) ₁₁ O—PO (OH) ₂ was used for the long-chain alkyl phosphate used in the first particles of Example 13, and the long-chain alkyl phosphate was used for the treatment. A 1% by mass diethylene glycol diethyl ether solution of acid ester was used. The surface tension of the first particles treated with the long-chain alkyl phosphate was 24 mN / m. The surface tension of the second particles treated with ricinoleic acid diglyceride phosphate was 6 mN / m greater than the surface tension of the first particles treated with long-chain alkyl phosphate.

(Comparative Example 1)
An ink set was manufactured in the same manner as in Example 1 except that the second ink was omitted and the first ink was used instead, so that the two inks were used.
(Comparative Example 2)
An ink set was manufactured in the same manner as in Example 1 except that the first ink was omitted, and the second ink was used instead, so that the second ink was used.
(Comparative Example 3)
Each ink was prepared in the same manner as in Example 1 except that the components other than the metal powder were changed to the following, and an ink set was obtained. Each of the obtained inks does not contain a component that is cured by irradiation with ultraviolet rays.

<First ink component>
-1st particle | grains similar to Example 1: 2.0 mass%
・ Glycerin: 10.0% by mass
・ 1,2-propanediol: 5.0% by mass
-Surfactant (BYK348 manufactured by Big Chemie): 0.5% by mass
・ Ion-exchanged water: remainder <component of second ink>
-2nd particle | grains similar to Example 1: 2.0 mass%
・ Glycerin: 10.0% by mass
・ 1,2-propanediol: 5.0% by mass
-Surfactant (BYK348 manufactured by Big Chemie): 0.5% by mass
・ Ion-exchange water: balance

For each of the above examples and comparative examples, the composition of each ink constituting the ink set is shown in Tables 1 and 2. In the table, phenoxyethyl acrylate is “PEA”, 2- (2-hydroxyethoxy) ethyl acrylate is “VEEA”, tripropylene glycol diacrylate is “TPGDA”, dipropylene glycol diacrylate is “DPGDA”, and N-vinyl. Caprolactam is “VC”, benzyl methacrylate is “BM”, dimethyloltricyclodecane diacrylate is “DMTCDDA”, aminoacrylate is “AA”, urethane acrylate is “UA”, and Irgacure 819 (manufactured by Ciba Japan) is “ ic819 ", Speedcure TPO (manufactured by ACETO)" scTPO ", Speedcure DETX (manufactured by Lambson)" scDETX ", UV-3500 (manufactured by Big Chemie)" UV3500 ", p- The butoxy phenol "pMP", a 4-hydroxybutyl acrylate "HBA" showed "GL" glycerin, 1,2-propanediol "1,2PD" BYK348 a (manufactured by BYK-Chemie GmbH) in "BYK348". In addition, the observation is performed for each arbitrary 10 metal particles contained in each ink, and the area S ₁ [μm ² ] when observed from the direction in which the projected area is maximized (when viewed in plan), and the observation The ratio (S ₁ / S ₀ ) to the area S ₀ [μm ² ] when observed from the direction in which the area when observed is the maximum among the directions orthogonal to the direction was determined. This is shown together with 2. In addition, the viscosity at 20 ° C. of each ink constituting the ink set of each of the above examples measured according to JIS Z8809 using a vibration viscometer is 3 mPa · s or more and 15 mPa · s or less. The value was within the range.

[2] Droplet discharge stability evaluation (discharge stability evaluation)
Using the ink sets of the respective Examples and Comparative Examples, evaluations by the following tests were performed.
First, a droplet discharge device installed in a chamber (thermal chamber) and the ink sets of the respective examples and comparative examples are prepared, and the driving waveform of the piezo element is optimized, at 25 ° C. and 55% RH. Under the environment, for each color ink, 2 million droplets (2000000 droplets) were continuously discharged from each nozzle of the droplet discharge head. Thereafter, the operation of the droplet discharge device was stopped, and the droplet discharge device was left in an environment of 25 ° C. and 55% RH for 120 hours with each ink filled.

  After that, 3 million droplets (3 million droplets) were continuously discharged from each nozzle of the droplet discharge head in an environment of 25 ° C. and 55% RH. The average deviation amount d from the center aiming position of the center position of each landed droplet for the 3000000 droplets ejected from the designated nozzle near the center of the droplet ejection head after being left for 120 hours. Values were obtained and evaluated according to the following five-step criteria. It can be said that the smaller the value is, the more effectively the occurrence of flight bending is prevented.

A: The average value of the shift amounts d is less than 0.09 μm.
B: The average value of the shift amount d is 0.09 μm or more and less than 0.15 μm.
C: The average value of the shift amount d is 0.15 μm or more and less than 0.18 μm.
D: The average value of the shift amounts d is 0.18 μm or more and less than 0.22 μm.
E: The average value of the shift amounts d is 0.22 μm or more.

[3] Storage stability evaluation of each ink (long-term stability evaluation)
About the 1st ink which comprises the ink set of each said Example and each comparative example, after leaving it to stand in a 40 degreeC environment for 30 days, visual observation was performed and it evaluated according to the following 5 steps | paragraphs of criteria.
A: No aggregation or sedimentation of the metal powder is observed.
B: Almost no aggregation or sedimentation of the metal powder is observed.
C: Slight aggregation / sedimentation of metal powder is observed.
D: Aggregation / sedimentation of metal powder is clearly observed.
E: Aggregation / sedimentation of metal powder is remarkably observed.

[4] Curability About each ink which comprises the ink set of each said Example and each comparative example, it introduce | transduces into Epson inkjet printer; PM800C, Mitsubishi Resin Co., Ltd. make, Diafoil G440E (thickness 38 micrometers) ), Solid printing was performed at an ink amount of 9 g / m ^2. Immediately after printing, an LED-UV lamp; Foseon RX RXrefly (gap 6 mm, 1000 mW / cm ² ) was used for ultraviolet irradiation. Whether the ink was cured or not was evaluated and evaluated according to the following five criteria. Each ink was ejected to the same position, and the ejection amount was set so that the first ink and the second ink had a volume ratio of 1: 2. Whether the ink was cured or not was determined by rubbing the surface with a cotton swab and not adhering uncured ink. In addition, whether it corresponds to the irradiation amount of the following AE can be calculated by how many seconds the lamp is irradiated.

A: Cured with an ultraviolet irradiation dose of less than 100 mJ / cm ² .
B: It hardened | cured with the ultraviolet irradiation amount of 100 mJ / cm < ² > or more and less than 200 mJ / cm < ² >.
C: Cured with an ultraviolet irradiation amount of 200 mJ / cm ² or more and less than 500 mJ / cm ² .
D: It hardened | cured with the ultraviolet irradiation amount of 500 mJ / cm < ² > or more and less than 1000 mJ / cm < ² >.
E: It hardens | cures by the ultraviolet irradiation amount of 1000 mJ / cm < ² > or more. Or it does not cure at all.

[5] Manufacture of recorded matter An interior panel as a recorded matter was manufactured as follows using the ink sets of each Example and each Comparative Example.
First, the ink set immediately after manufacture was put into an ink jet apparatus.
Then, each ink which comprises an ink set was discharged on the base material (recording medium) which has the curved surface part shape | molded using the polycarbonate (Asahi Glass Co., Ltd. make, Carboglass polish 2mm thickness). At this time, the first ink and the second ink were set to have a volume ratio of 1: 2, and each ink was ejected to the same position.

After that, irradiation of ultraviolet rays having a spectrum having maximum values at wavelengths of 365 nm, 380 nm, and 395 nm was irradiated for 20 seconds at an irradiation intensity of 180 mW / cm ² to cure the ink on the base material to obtain an interior panel as a recorded matter. It was.
Using the method as described above, 10 interior panels (recorded matter) were manufactured using the ink sets of each Example and each Comparative Example.

[6] Evaluation of recorded matter The following evaluation was performed on each recorded matter obtained as described above.
[6.1] Appearance evaluation of recorded matter Each recorded matter produced in each of the examples and comparative examples was visually observed and evaluated according to the following four-stage criteria.
A: The metal-specific texture is very high and the aesthetic appearance is very good.
B: The metal-specific texture is slightly high and the aesthetic appearance is slightly good.
C: The metal-specific texture is slightly low and the aesthetic appearance is slightly poor.
D: The texture peculiar to metal is low and the aesthetic appearance is poor.

[6.2] Glossiness The glossiness at a turning angle of 60 ° was measured using a glossiness meter (MINOLTA MULTI GLOSS 268) for the printed portion of each recorded matter produced in each of the above examples and comparative examples. The evaluation was performed according to the criteria.
A: Glossiness is 300 or more.
B: Glossiness is 200 or more and less than 300.
C: Glossiness is 100 or more and less than 200.
D: Glossiness is 60 or more and less than 100.
E: Glossiness is less than 60.

[6.3] Scratch resistance For the recorded materials according to the respective examples and comparative examples, a rub resistance test was performed according to JIS K5701 using a Southerland Love Tester after 48 hours had passed since the production of the recorded materials. In the same manner as described in [6.2] above, the gloss (60 ° angle) is measured on the printed portion of the recorded matter after the abrasion resistance test, and before and after the abrasion resistance test. The reduction rate of glossiness was determined and evaluated according to the following criteria.

A: The reduction rate of glossiness is less than 10%.
B: The reduction rate of glossiness is 10% or more and less than 20%.
C: The reduction rate of glossiness is 20% or more and less than 30%.
D: The reduction rate of glossiness is 30% or more.
These results are shown in Table 3.

  As is apparent from Table 3, the ink set of the present invention was able to be suitably used for forming a printed part having high curability of the ejected matter and excellent metal-specific texture such as gloss. Further, the ink constituting the ink set of the present invention was excellent in droplet ejection stability and storage stability. On the other hand, in the comparative example, satisfactory results were not obtained particularly in terms of the curability of the ejected matter and the glossiness of the recorded matter.

Although not shown in the table, the first ink and the second ink were set to have a volume ratio of 1: 5 so that each ink was ejected to the same position. In this case, the appearance and glossiness of the recorded matter was B, but the curability of the discharged matter was A. From this, it is recognized that according to the present invention, both the curability of the discharged material and the appearance of the recorded material can be achieved.
In addition, when the metal particles were changed to stainless steel (SUS316L), the results were the same as when aluminum was used.

Claims (13)

An ink set comprising a plurality of ultraviolet curable ink jet inks ejected by an ink jet method,
The ultraviolet curable ink-jet ink has a scaly shape, and includes a first ink containing first particles obtained by surface-treating the surface of metal particles, and a first ink having a surface tension larger than that of the first particles. And a second ink containing two particles.   The ink set according to claim 1, wherein the surface treatment applied to the first particles is a treatment of forming a film containing a fluorine-based compound on the surface of the metal particles.   The ink set according to claim 1, wherein the second particles have a scale shape.   4. The ink set according to claim 1, wherein the second particle is a particle obtained by performing a surface treatment on the surface of the metal particle so that the surface tension is larger than that of the first particle. 5. .   The ink set according to any one of claims 1 to 4, wherein the surface treatment applied to the second particles is a treatment of forming a film containing a phosphate ester compound on the surface of the metal particles.   The ink set according to any one of claims 1 to 5, wherein the metal particles in the first particles are mainly composed of aluminum.   The ink set according to claim 1, wherein the metal particles in the first particles and the metal particles in the second particles are made of metal materials having the same composition.   The ink set according to any one of claims 1 to 7, wherein an average particle diameter of the first particles is 500 nm or more and 2.0 µm or less.   The ink set according to claim 1, wherein the first ink contains phenoxyethyl acrylate as a polymerizable compound that is polymerized by irradiation with ultraviolet rays.   In addition to the phenoxyethyl acrylate, the first ink includes 2- (2-vinyloxyethoxy) ethyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and 4-hydroxy as the polymerizable compound. The ink set according to claim 1, comprising at least one selected from the group consisting of butyl acrylate.   The ink set according to claim 1, wherein the first ink contains at least one of dimethylol tricyclodecane diacrylate and amino acrylate as a polymerizable compound that is polymerized by irradiation with ultraviolet rays.   A first ink that has a scaly shape and includes first particles obtained by subjecting the surface of the metal particles to surface treatment, and a second ink that is cured by irradiation with ultraviolet rays and has a surface tension larger than that of the first particles. A recorded matter produced by applying a second ink containing particles and cured by irradiation with ultraviolet rays to the same position on a recording medium by an inkjet method and irradiating with ultraviolet rays.   The recorded matter according to claim 12, wherein the first ink and the second ink are applied so that the content ratio of the second particles is larger than the content ratio of the first particles.