JP2016169393A - Photo-curing ink composition for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photo-curing ink composition for ink jet recording which can form easily a metal gloss surface having good glossiness, and is suitable for an ink jet recording method.SOLUTION: A photo-curing ink composition for ink jet recording contains a metal pigment, a polymerizable compound and a polymerization initiator. The metal pigment consists of tabular grains in each of which a metal layer or an alloy layer, and at least one selected from a resin layer and a silicon oxide layer are laminated.SELECTED DRAWING: None

Description

  The present invention relates to a photocurable ink composition for inkjet recording.

  In recent years, there is an increasing demand for printed materials having a glossy metallic surface on the printed surface. As a method for obtaining a printed matter having a metallic glossy surface, conventionally, for example, a printing method using a metal foil on a recording medium having a printing surface with high flatness, or a plastic film having a smooth printing surface. On the other hand, there are a method of vacuum-depositing a metal, a method of printing on a recording medium using a metal pigment ink, and a press working.

  On the other hand, the ink jet recording method is a printing method in which printing is performed by causing droplets of an ink composition to fly and adhere to a recording medium such as paper. This recording method is characterized in that a high-resolution, high-quality image can be printed at a high speed with a relatively small apparatus configuration. Therefore, it has been studied to produce a recorded matter having a metallic glossy surface by such an ink jet recording method. For example, in Japanese Patent Application Laid-Open No. 2002-179960, an ink composition containing, as a pigment, a metal film formed on the surface of plastic spherical particles is applied to a recording medium with an ink jet recording apparatus, and then pressed. A printing technique for smoothing the surface is disclosed (Patent Document 1).

On the other hand, in recent years, development of photocurable ink that is cured by light such as ultraviolet rays has been advanced. This photo-curable ink is characterized in that it can be quickly dried and recorded with little ink bleeding with respect to a non-absorbing medium such as plastic that does not absorb ink by an ink jet recording method. The photocurable ink is composed of a polymerizable compound, a polymerization initiator, a pigment, and the like.
[Prior art documents]
[Patent Literature]
JP 2002-179960 A

  If a metal pigment is used as a pigment in the photocurable ink, there is a possibility that a metallic glossy surface can be formed by an inkjet recording method without passing through a step such as pressing. However, in order to realize such a method, there are the following problems.

  One is that the size of the metal pigment is limited. In the ink jet recording method, since it is necessary to use a metal pigment having a diameter smaller than the nozzle diameter of the ink jet recording apparatus, it is difficult to obtain a printing surface having a sufficient metallic luster.

  One is that it becomes difficult to cure the ink printing surface. If a metal pigment is used as the pigment of the photocurable ink, even if the ink print surface is irradiated with light, the metal pigment may absorb and reflect light, resulting in insufficient light amount and insufficient curing of the print surface. It was. Furthermore, when the photocuring mechanism is a cationic polymerization reaction system, the generated acid and metal react with each other, which is dangerous, and further, the metal pigment is deteriorated, so that a desired metallic glossy image can be obtained. There wasn't.

In addition, when light is applied to sufficiently cure a photocurable ink containing a metal pigment, heat is generated by the light absorbed by the metal pigment, and the recording medium is damaged. There are problems such as the fact that the material is scattered around and may cause safety problems.

  Furthermore, there was a problem of increasing the size of the apparatus. The light source for irradiating powerful light has increased in scale, and the advantages of the ink jet recording method that can adopt a compact and safe apparatus configuration as compared with other printing methods have been impaired.

  One of the objects of some aspects of the present invention is to provide a photocurable ink composition for ink jet recording which can easily form a metallic glossy surface with good glossiness and is suitable for an ink jet recording method. It is to be.

The photocurable ink composition for ink jet recording according to the present invention comprises:
Metal pigments,
A polymerizable compound;
A polymerization initiator;
Containing
The metal pigment is
A metal or alloy layer;
At least one selected from a resin layer and a silicon oxide layer;
Is a laminated tabular grain.

  Such a photocurable ink composition for ink jet recording can easily form a metallic glossy surface with good glossiness and can be suitably used for an ink jet recording method.

In the photocurable ink composition for inkjet recording according to the present invention,
A color material layer may be further provided between the metal or alloy layer, the resin layer, and the silicon oxide layer in the metal pigment.

In the photocurable ink composition for inkjet recording according to the present invention,
The tabular grains are 50% average grains in a circle-equivalent diameter determined from the area of the XY plane of the tabular grains when the major axis on the plane of the tabular grains is X, the minor axis is Y, and the thickness is Z. The diameter R50 may be 0.5 to 3 μm, and the shape satisfies the condition of R50 / Z> 5.

In the photocurable ink composition for inkjet recording according to the present invention,
The metal or alloy layer may be made of aluminum or an aluminum alloy.

In the photocurable ink composition for inkjet recording according to the present invention,
The polymerizable compound may be a cationic polymerization compound.

In the photocurable ink composition for inkjet recording according to the present invention,
The polymerizable compound may be a radical polymerization compound.

In the photocurable ink composition for inkjet recording according to the present invention,
Furthermore, a hindered amine compound can be contained.

In the photocurable ink composition for inkjet recording according to the present invention,
The end face of the metal or alloy layer of the metal pigment may be subjected to a chemical conversion treatment.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

1. Photocurable ink composition for inkjet recording The photocurable ink composition for inkjet recording according to the present invention contains a metal pigment, a polymerizable compound, and a polymerization initiator.

1.1. Metal Pigment The metal pigment contained in the photocurable ink composition for ink jet recording according to the present embodiment has a metallic luster when the photocurable ink composition for ink jet recording is attached to a recording medium or the like. It has the function to give.

  The metal pigment contained in the photocurable ink composition for inkjet recording of the present embodiment is a composite pigment prepared as follows.

  The composite pigment of the first form is obtained by peeling and pulverizing the pigment layer from the base of the composite pigment of the first form. The base material of the composite pigment of the first form has a structure in which a pigment layer is laminated on one side or both sides of a sheet-like substrate surface. The base pigment layer of the composite pigment of the first form is obtained by sequentially laminating a silicon oxide layer / (metal or alloy layer) / silicon oxide layer. The pigment layer is peeled off from the sheet-like base material and pulverized to form a composite pigment of the first form.

  The composite pigment of the second form is obtained by peeling and pulverizing the pigment layer from the base of the composite pigment of the second form. The base material of the composite pigment of the second form has a structure in which a pigment layer is laminated on the surface of the sheet-like substrate as in the first form. The base pigment layer of the composite pigment of the second form is a laminate of resin layer / (metal or alloy layer) / resin layer. The pigment layer is peeled off from the sheet-like substrate and pulverized to form a composite pigment of the second form.

  In the first embodiment, the composite pigment of the third embodiment in which a color material layer is provided between the silicon oxide layer and the metal or alloy layer, and in the second embodiment, the resin layer and the metal or Any of the composite pigments of the fourth form in which a color material layer is provided between the alloy layer and the alloy layer can be suitably used as a metal pigment contained in the ink composition for ink jet recording of the present embodiment.

  The metal pigment of this embodiment is the composite pigment described above, and has a structure in which a metal or alloy layer is covered with a silicon oxide layer or a resin layer. Therefore, the metal or alloy layer is protected by the silicon oxide layer or the resin layer. Therefore, unlike conventional metal pigments, the metal or alloy layer is unlikely to cause discoloration or decoloration and has good storage stability. Moreover, in the composite pigment (the second form or the fourth form described above) in which the resin layers are laminated, the resin layer can serve as a protective colloid. Therefore, such a composite pigment dispersion can be a more stable metal pigment dispersion.

  Moreover, desired colorability can be provided by providing a color material layer between layers like the composite pigment of the said 3rd form and the 4th form.

Since the metal pigment of the present embodiment is a laminate and has a flat plate structure as described above, it has excellent storage stability and dispersion stability in the photocurable ink composition for inkjet recording. Good ejection properties can be imparted also during ink jet recording. Furthermore, since the metal pigment of the present embodiment has a laminated plate-like structure, it is easier to transmit light in the thickness direction than a pigment having a general spherical shape, and thus light shielding is suppressed. Therefore, it is extremely suitable for a photocurable ink composition for inkjet recording. Moreover, since mechanical strength improves by setting it as a laminated structure, the metallic gloss fall by the deformation | transformation of a metal pigment can be prevented.

  Further, when the metal pigment is produced by pulverization, an exposed portion of the metal or alloy layer is generated on the end face of the metal pigment. Such exposed portions may have high chemical activity. For this reason, interfacial peeling or the like may occur due to the reaction with moisture, water vapor or the like and corrosion. As a result, the metal or alloy may change to a metal oxide, a metal hydroxide, or the like, which may cause problems such as a decrease in metallic luster or loss of metallic luster. Therefore, in order to suppress such a problem, it is more preferable to form a chemically stable protective layer by subjecting the end face of the metal pigment to chemical conversion treatment with a chemical oxidizing agent.

  Hereinafter, the component of the composite pigment of this embodiment, the constituent components of each layer constituting the composite pigment, the layer forming method, the peeling / pulverizing method, and the like will be described.

(Pigment layer)
First, the pigment layer in the laminated plate-like structure of the composite pigment base material of this embodiment will be described.

  The base pigment layer of the composite pigment according to the first embodiment of the present embodiment has a structure in which a silicon oxide layer / (metal or alloy layer) / silicon oxide layer is sequentially laminated. The total thickness of the pigment layer is preferably in the range of 100 to 500 nm. If the thickness is less than 100 nm, the mechanical strength may be insufficient. If the thickness exceeds 500 nm, the strength becomes too high, and processing such as pulverization and dispersion may be difficult.

  The metal or alloy layer in the pigment layer is not particularly limited as long as it has a function such as exhibiting metallic luster, but aluminum, silver, gold, nickel, chromium, tin, zinc, indium, titanium Etc., and at least one of these simple metals, metal compounds or alloys thereof and mixtures thereof can be suitably used. The material of the metal or alloy layer in the pigment layer is more preferably made of aluminum or an aluminum alloy. In the case of selecting an aluminum alloy, the other elements contained in the aluminum are not limited as long as the aluminum alloy can exhibit a metallic luster. Examples of the alloy element of aluminum include at least one selected from silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, and copper.

  Although a metal or alloy layer is not specifically limited, For example, it can form by vacuum evaporation, an ion plating, or sputtering method. The thickness of these metal or alloy layers is not particularly limited, but is preferably in the range of 15 to 150 nm. When the thickness is less than 15 nm, the performance such as reflectivity and glitter as a metal pigment may be insufficient. When the thickness exceeds 150 nm, the apparent specific gravity increases, and the dispersion stability of the composite pigment may decrease. An unnecessary increase in the thickness of the metal or alloy layer only leads to an increase in the weight of the metal pigment particles, and even if the film thickness is thicker than 150 nm, the reflectivity and the glitter are not changed so much.

  The silicon oxide layer in the pigment layer is not particularly limited as long as it is a layer containing silicon oxide. The silicon oxide layer can be formed from, for example, silicon alkoxide or a polymer thereof by a sol-gel method.

As a method for forming the silicon oxide layer, for example, it can be formed by applying an alcohol solution in which the silicon alkoxide or a polymer thereof is dissolved to a target surface, followed by heating and baking. As a specific example of such a raw material of the silicon oxide layer, for example, a material available from Colcoat Co., Ltd. can be cited as a model number “HAS-6”. In this case, the application of the raw material solution for the silicon oxide layer can be performed by commonly used methods such as gravure coating, roll coating, blade coating, extrusion coating, dip coating, and spin coating. Further, after application and drying, the surface can be smoothed by calendaring if necessary.

  Although the thickness of a silicon oxide layer is not specifically limited, The range of 50-150 nm is preferable. If the thickness is less than 50 nm, the mechanical strength may be insufficient. If the thickness exceeds 150 nm, the mechanical strength may be too high, so that pulverization / dispersion may be difficult, and peeling may occur at the interface with the metal or alloy layer. There is.

  The base pigment layer of the composite pigment according to the second embodiment of the present embodiment has a structure in which a resin layer / (metal or alloy layer) / resin layer is sequentially laminated. The metal or alloy layer is the same as in the case of the base material of the composite pigment of the first form, and thus description thereof is omitted.

  The resin layer in the original pigment layer of the composite pigment of the second form is not particularly limited, but for example, polymers such as polyvinyl alcohol, polyalkylene glycol, polyacrylic acid, polyacrylamide, hydroxypropyl cellulose, It can be composed of cellulose derivatives such as carboxymethyl cellulose and cellulose acetate butyrate, polyvinyl acetal, polyvinyl butyral, acrylic acid copolymer or modified nylon resin. In addition, as a material which comprises a resin layer, when the sheet-like base material surface mentioned later and a resin layer contact | abut, it is more preferable to select what has peelability from a sheet-like base material surface.

  The thickness of the resin layer in the original pigment layer of the composite pigment of the second form is not particularly limited, but is preferably 0.5 to 50 μm, and more preferably 1 to 10 μm. If the thickness is less than 0.5 μm, the effect of protecting the metal or alloy layer may be insufficient, and the effect as a dispersion resin may be insufficient, so that sufficient dispersion stability may not be imparted to the ink composition. Further, when the thickness of the resin layer in the base pigment layer of the composite pigment of the second form exceeds 50 μm, the interface between the metal or alloy layer and the resin layer when rolled in the base state It may be easy to peel off.

  As a method for forming the resin layer in the base material of the composite pigment of the second form, for example, a solution obtained by dissolving the above-described resin in an appropriate solvent may be applied to the target surface and dried. it can. In this case, the resin layer can be applied by commonly used methods such as gravure coating, roll coating, blade coating, extrusion coating, dip coating, and spin coating. Moreover, after application | coating and drying, if necessary, glossiness can also be provided by smoothing the surface by a calendar process.

  The base pigment layer of the composite pigment according to the third and fourth embodiments of the present embodiment has a structure in which a color material layer is provided between a metal or alloy layer and a silicon oxide layer or a resin layer. That is, the composite pigments of the third and fourth embodiments of the present embodiment are provided with at least one color material layer so as to be adjacent to the metal or alloy layer in the pigment layer.

The color material layer has a function of imparting an arbitrary color tone and hue to the composite pigment of the present embodiment in addition to the metallic luster and glitter derived from the metal or alloy layer. The color material contained in the color material layer is not particularly limited, and general known dyes and pigments can be suitably used. Further, the color material layer contains a polymer dispersant such as a fiber resin such as polyvinyl butyral resin, cellulose acetate butyrate, carboxymethyl cellulose, and hydroxypropyl cellulose as a dispersant for the color material solution or dispersion. May be. A method for forming the color material layer is not particularly limited. For example, the color material layer can be formed by coating a target surface with a solution or dispersion of a color material. In this case, the coating can be performed by commonly used methods such as gravure coating, roll coating, blade coating, extrusion coating, dip coating, and spin coating. Moreover, after application | coating and drying, if necessary, glossiness can also be provided by smoothing the surface by a calendar process.

  Moreover, it is preferable that the exposed part of the metal or alloy layer generated on the end face of the metal pigment by the metal pigment pulverization treatment is subjected to chemical conversion treatment with a chemical oxidizing agent to form a chemically stable protective layer. In this case, examples of the chemical oxidizing agent suitable for use include non-volatile organic acids such as hydrogen peroxide, chromic acid, phosphoric acid, phosphate, citric acid and malic acid.

  Note that the laminated structure of the composite pigments of the first to fourth embodiments of the present embodiment may be repeated.

[Sheet substrate]
Although it does not specifically limit as a sheet-like base material used for the raw material of the composite pigment of this embodiment, Polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate, polyester films, such as polyethylene naphthalate, 66 nylon, 6 Examples include releasable films such as polyamide films such as nylon, polycarbonate films, triacetate films, and polyimide films. Among these, a particularly preferable sheet-like substrate is polyethylene terephthalate or a copolymer thereof.

  Although the thickness of these sheet-like base materials is not specifically limited, 10-150 micrometers is preferable. If it is 10 μm or more, the handleability is good in the process or the like, and if it is 150 μm or less, there is flexibility and it is difficult to cause problems in roll forming, peeling treatment and the like.

[Peeling layer]
A release layer can be provided on one or both surfaces of the sheet-like base material used for the composite pigment base material of the present embodiment. By providing the release layer, the release treatment between the sheet-like substrate and the pigment layer can be made easier. The release layer is not particularly limited, and a fiber resin such as polyvinyl alcohol resin, polyvinyl butyral resin, cellulose acetate butyrate, carboxymethyl cellulose, and hydroxypropyl cellulose can be used. In the case of the base materials of the second composite pigment and the fourth composite pigment, when the release layer is provided, the material constituting the release layer and the material constituting the resin layer are at least soluble in a specific solvent. It is preferable to make it different in this point.

[Removal and pulverization of composite pigment]
The composite pigment of this embodiment is obtained by peeling the pigment layer of the composite pigment base material from the sheet-like base material, pulverizing and refining.

  The method for removing the composite pigment is not particularly limited. For example, there is a method of immersing the composite pigment base in a liquid. In addition, for example, there can be mentioned a method in which the composite pigment base is immersed in a liquid and subjected to ultrasonic treatment, and the peeling treatment and the grinding treatment of the peeled pigment layer are simultaneously performed. As a method for pulverizing the peeled pigment layer, a mechanical pulverization method can also be used. Furthermore, a composite pigment having a target particle size can be classified and collected from the pulverized product so that the particle size has a desired distribution.

The metal pigment (composite pigment) of this embodiment as described above further has the following properties. The metal pigment having the above laminated structure is a tabular grain having a tabular grain shape. The “tabular grains” are grains having a substantially flat surface (XY plane) and a substantially uniform thickness (Z) and a flat plate shape. And the thickness Z of this board means the particle | grains smaller than the magnitude | size (size on an XY plane) of the direction of the board surface of this board. In the present specification, as a parameter of the shape of the tabular grain, the major axis on the plane (plate surface direction) of the tabular grain is X
The minor axis is defined as Y, and the thickness of the tabular grains is defined as Z.

  The metallic pigment having such a flat shape is arranged so that the normal direction of the recording medium and the thickness direction of the metallic pigment are aligned when the photocurable ink composition for inkjet recording is attached to the recording medium. Cheap. Therefore, it is possible to reduce the amount of metal pigment required when forming a glossy metallic surface on the recording medium. Further, since the metal pigment has a flat plate shape, it is easy to generate transmitted light when irradiating the printing surface with light, and the printing surface of the photocurable ink composition is easily cured.

  In order to increase the metallic luster of the printing surface formed on the recording medium and to further reduce the amount of light necessary to cure the printing surface, the metal pigment has a major axis of X, a minor axis of Y, and a thickness. When Z is Z, it is more preferable that the 50% average particle diameter R50 of the equivalent circle diameter determined from the area of the XY plane is 0.5 to 3 μm, and the shape satisfies the condition of R50 / Z> 5.

  Here, the “equivalent circle diameter” is the diameter of a circle having the same area as the area when the XY plane of the tabular grain is projected in the Z direction. The equivalent circle diameter can be measured by, for example, a particle image analyzer (for example, FPIA-2100, FPIA-3000, FPIA3000S manufactured by Sysmex Corporation), image analysis of a microscope observation result, or the like.

  The 50% average particle diameter R50 of the equivalent-circle diameter of the tabular grains is equivalent to the equivalent-circle diameter corresponding to 50% of the total number of grains measured when the distribution of the number of particles (frequency) with respect to the equivalent circle diameter is drawn. Refers to that.

  If it does in this way, the flatness of the surface of the printing surface formed in a recording medium can be improved, and the metallic glossiness of this printing surface can be raised. Furthermore, since the amount of light transmitted through the metal pigment can be increased, the amount of light irradiation necessary for curing the printed surface can be reduced.

  The metal pigment produced by the above method can be characterized by the properties of the metal vapor deposition film formed during the production process. That is, it is easy to measure the light transmittance of the metal or metal compound layer in the process of producing the metal pigment. In addition, it is considered that the metal pigment obtained by pulverizing this has the same light transmittance as that of the metal or alloy layer. The light transmittance of the metal or alloy layer can be measured by, for example, a UV integrated light meter C9536, H9535 series manufactured by Hamamatsu Photonics Co., Ltd., a UV intensity meter UM-10 manufactured by Konica Minolta Holdings, Inc., or the like.

  The metal pigment of the present embodiment is used for light transmittance in the thickness direction of a metal or alloy layer, particularly for curing treatment, in order to reduce the amount of light necessary for curing the printing surface formed on the recording medium. More preferably, the transmittance of light in the vicinity of a wavelength of 350 nm to 450 nm is 0.5% or more.

  The maximum particle diameter Rmax of the equivalent circle diameter determined from the area of the XY plane of the metal pigment tabular particles is clogged with a nozzle when a photocurable ink composition for inkjet recording is applied using an inkjet recording apparatus. Is preferably 10 μm or less.

  The content of the metal pigment in the photocurable ink composition for inkjet recording is preferably 0.1 to 2% by mass, and more preferably 0.5 to 1.75% by mass. Below this range, good metallic luster may not be obtained on the printed surface, and beyond this range, the curability of the printed surface may be impaired.

1.2. Polymerizable compound Examples of the polymerizable compound contained in the photocurable ink composition for inkjet recording of the present embodiment include a monofunctional polymerizable compound and a polyfunctional polymerizable compound. These polymerizable compounds are not particularly limited as long as they are compounds that cause a polymerization reaction upon application of energy and are cured, and are used regardless of the type of monomer, oligomer, linear polymer, or dendritic polymer. can do.

  Examples of the radical polymerizable compound that can be used in the photocurable ink composition for inkjet recording include (meth) acrylates, (meth) acrylamides, aromatic vinyls, allyl compounds, N-vinyl compounds, vinyl esters ( Vinyl acetate, vinyl propionate, vinyl versatate, etc.), allyl esters (eg, allyl acetate), halogen-containing monomers (vinylidene chloride, vinyl chloride, etc.), vinyl ethers (methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxy vinyl ether) , 2-ethylhexyl vinyl ether, methoxyethyl vinyl ether, cyclohexyl vinyl ether, chloroethyl vinyl ether, etc.), vinyl cyanide ((meth) acrylonitrile, etc.), olefins (eth Emissions, propylene, etc.) and the like. In the present specification, when referring to both or one of “acrylate” and “methacrylate”, when referring to “(meth) acrylate” and both or one of “acryl” and “methacryl”, “(meth)” "Acrylic" may be described respectively.

  In the present embodiment, as the (meth) acrylates, general monofunctional (meth) acrylates and polyfunctional (meth) acrylates can be suitably used. Among (meth) acrylates, typical examples of polyfunctional (meth) acrylates include compounds having a plurality of (meth) acryloyl groups in the molecule, and (meth) acryloyl groups in linear polymers. And a compound in which a plurality of (meth) acryloyl groups are bonded to a dendritic polymer can be suitably used. In particular, a compound in which a plurality of (meth) acryloyl groups are bonded to a dendritic polymer is suitable in this embodiment. Specific examples thereof include a compound available from Osaka Organic Chemical Industry Co., Ltd. under the trade name “Biscoat # 1000”. Is mentioned. The compound is a hyperbranched polymer synthesized by branching a functional group with dipentaerythritol as a core, and since the density of acryloyl groups near the surface of the polymer molecule is high, it can be suitably used as a polymerizable compound. it can.

  (Meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, Nn-butyl (meth) acrylamide, Nt -Butyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) Examples include acrylamide and (meth) acryloylmorpholine.

  Specific examples of aromatic vinyls include styrene, methyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octylstyrene, 4-octylstyrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allylstyrene, isopropenylstyrene, butenylstyrene, octenylstyrene, 4-t- Butoxycarbonyl styrene, 4-methoxystyrene, and a 4-t-butoxystyrene.

The allyl compound has a 2-propenyl structure (—CH ₂ CH═CH ₂ ). The 2-propenyl group is also called an allyl group, and is a common name in the IUPAC nomenclature. Specific examples of allyl compounds include, for example, ethylene glycol monoallyl ether, allyl glycol (for example, available from Nippon Emulsifier Co., Ltd.), trimethylolpropane diallyl ether, pentaerythritol triallyl ether, glycerin monoallyl ether (above, for example, And a polyoxyalkylene compound having an allyl group, which is a trade name of UNIOX, UNILOP, polyserine, UNISafe (available from NOF Corporation), and the like.

The N-vinyl compound has a structure in which a vinyl group is bonded to nitrogen (> N—CH═CH ₂ ). The N-vinyl compound has radical polymerizability. Specific examples of the N-vinyl compound include, for example, N-vinylformamide, N-vinylcarbazole, N-vinylindole, N-vinylpyrrole, N-vinylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam, and their Derivatives, and N-vinylformamide is particularly preferable among these compounds. N-vinylformamide can be obtained from Arakawa Chemical Industries, Ltd., for example.

  Moreover, since the compound which has a functional group containing active hydrogen as a polymeric compound tends to generate | occur | produce a radical, it is further preferable in order to improve polymerizability. In addition, such a compound is more preferable because it is less susceptible to oxygen inhibition and can be cured with relatively low energy. Examples of the functional group having active hydrogen include an amino group, an imino group, and an alcoholic hydroxyl group, and the photocurable ink composition for inkjet recording preferably further contains a polymerizable compound having these groups. . Moreover, you may have a thiol group instead of alcoholic hydroxyl group. Specific examples of the compound having a functional group containing active hydrogen include, for example, N-vinylformamide and urethane oligomer (for example, trade names: U-4HA, U-15HA, available from Shin-Nakamura Chemical Co., Ltd.) , Ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, trimethylolpropane diallyl ether, trimethylolpropane monoallyl ether, glycerin monoallyl ether, allyl glycidyl ether, pentaerythritol triallyl ether, hydroxybutyl vinyl ether, 2-hydroxyethyl (meta ) Acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, alkanethiol, alkylenethiol and the like.

  Moreover, the compound which has a functional group containing an ethylenically unsaturated double bond as a polymeric compound has high polymerizability, and it is further more preferable in order to improve the cure rate and curability of a printing surface. In addition, such a compound is more preferable because it is less susceptible to oxygen inhibition and can be cured with relatively low energy. Examples of the functional group containing an ethylenically unsaturated double bond include a vinyl group and an allyl group. Specific examples include the above-mentioned allyl compounds and vinyl compounds.

  Examples of the cationic polymerizable compound include an epoxy compound, a vinyl ether compound, an oxetane compound, and an oxirane compound.

  Examples of the epoxy compound include aromatic epoxides and alicyclic epoxides.

Examples of monofunctional epoxy compounds include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene. Monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3-vinylcyclohexene oxide, etc. Is mentioned.

  Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S di Glycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexyl) Rumethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate) Dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether Glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8- Examples include diepoxyoctane and 1,2,5,6-diepoxycyclooctane.

  Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of the monofunctional vinyl ether that can be used in the present embodiment include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether. , Cyclohexyl methyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl Vinyl ether, methoxypolyethylene Glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, Examples include chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

Examples of polyfunctional vinyl ethers include, for example, ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide. Divinyl ethers such as divinyl ether, trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hex Vinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide-added penta And polyfunctional vinyl ethers such as erythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.

  As the vinyl ether compound, di- or trivinyl ether compounds are preferable from the viewpoints of curability, adhesion to a recording medium, surface hardness of the formed image, and the like, and divinyl ether compounds are particularly preferable.

  The oxetane compound that can be used in the present embodiment refers to a compound having an oxetane ring, and a known oxetane compound is arbitrarily selected as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. Can be used.

  As the compound having an oxetane ring that can be used in the ink composition of the present embodiment, a compound having 1 to 4 oxetane rings in its structure is preferable. By using such a compound, it becomes easy to maintain the viscosity of the ink composition in a good handling property range, and it is possible to obtain high adhesion of the cured ink to the recording medium. .

  Examples of the monofunctional oxetane used in the present embodiment include, for example, 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, 3-ethyl-3- (2-ethyl). Hexyloxymethyl) oxetane, (3-ethyl-3-oxetanylmethoxy) methylbenzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy- [1- (3- Ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3-ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl ( 3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl- -Oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, ethyl diethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, Dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether 2-tribromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether , Butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl- 3-oxetanylmethyl) ether and the like.

Examples of polyfunctional oxetanes include 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3 -Bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, triethylene Glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-io Xetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3-) Oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) Ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxy) Tanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis (3-ethyl) -3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis (3-ethyl) -3-Oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3-ethyl-3- Kisetanirumechiru) ether, EO-modified bisphenol F (3- ethyl-3-oxetanylmethyl) include polyfunctional oxetanes such as ether.

  Among the oxetane compounds used in the present embodiment, it is preferable to use a compound having 1 to 2 oxetane rings from the viewpoint of the viscosity and tackiness of the ink composition.

  In the photocurable ink composition for ink jet recording of the present embodiment, these polymerizable compounds may be used alone or in combination of two or more, but it is effective for shrinkage during ink curing. From the viewpoint of suppressing the reaction, it is preferable to use at least one oxetane compound and at least one compound selected from an epoxy compound and a vinyl ether compound in combination.

  In addition to the polymerizable compounds listed above, known polymerizable compounds can be used. For example, the polymerizations described in JP-A-2008-138166, JP-A-2007-120991, JP-A-2008-88228, etc. Sexual compounds can be used.

  The content of the polymerizable compound in the photocurable ink composition for ink jet recording of the present embodiment is suitably 50% by mass to 95% by mass, preferably 60% by mass to 92% by mass with respect to the entire composition. More preferably, it is the range of 70 mass%-90 mass%.

1.3. Polymerization initiator The photocurable ink composition for ink-jet recording according to this embodiment contains a polymerization initiator. The polymerization initiator used in the photocurable ink composition for inkjet recording can generate active species by light. The light that can generate the active species of the polymerization initiator is, for example, ultraviolet light, visible light, far ultraviolet light, g-line, h-line, i-line, KrF excimer laser light, ArF excimer laser light in the range of 400 nm to 200 nm, or Examples include electromagnetic waves such as X-rays.

  Examples of the polymerization initiator contained in the photocurable ink composition for ink jet recording include aromatic ketones, aromatic onium salt compounds, organic peroxides, hexaarylbiimidazole compounds, ketoxime ester compounds, and borate compounds. , Azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and the like.

  In addition to the polymerization initiators listed above, known polymerization initiators can be used. For example, the polymerizations listed in JP-A-2008-138166, JP-A-2007-120991, JP-A-2008-88228, etc. An initiator can be used.

  Specific examples of the polymerization initiator include benzyl dimethyl ketal, α-hydroxyalkylphenone, α-aminoalkylphenone, acylphosphine oxide, oxime ester, thioxanthone, α-dicarbonyl, anthraquinone, Vicure 10, 30 (Staffer Chemical Company) Irgacure 127, 184, 500, 651, 2959, 907, 369, 379, 754, 1700, 1800, 1870, 819, OXE01, Darocur 1173, TPO, ITX (manufactured by Ciba Specialty Chemicals), Quanture CTX (Aceto Chemical), Kayacure, DETX-S (Nippon Kayaku), ESACURE KIP150 (Lamberti), yracureUVI-6692, CyracureUVR-6105 can be mentioned those available under the trade name (manufactured by Dow Chemical Co., Ltd.), and the like.

1.4. Other Components The photocurable ink composition for ink jet recording according to the present embodiment includes a colorant, a polymerization accelerator, a thermal radical polymerization inhibitor, a surfactant, and a wetting agent in addition to the polymerizable compound and the polymerization initiator. , Osmotic solvents, pH adjusters, preservatives, antifungal agents, and the like. Further, it may contain leveling additives, matting agents, polyester resins for adjusting the physical properties of recorded materials, polyurethane resins, vinyl resins, acrylic resins, rubber resins, and waxes as necessary. it can.

  The coloring material that can be used in the photocurable ink composition for inkjet recording may be either a dye or a pigment. Examples of the dye include various dyes that are usually used in inkjet recording, such as direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, and soluble vat dyes.

  There is no special restriction | limiting as a pigment, An inorganic pigment and an organic pigment can be mentioned. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinofullerone pigments). Dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like can be used. Of these colorants, it is more preferable to use a dye from the viewpoint that it is difficult to block light necessary for photocuring the polymerizable compound.

  The amount of the coloring material that can be used in the photocurable ink composition for inkjet recording is preferably 0.1% by mass to 25% by mass, and more preferably 0.5% by mass to 15% by mass.

When a pigment is used in the photocurable ink composition for inkjet recording, the average particle diameter of the pigment is preferably in the range of 10 nm to 200 nm, more preferably 50 nm to 150 n.
The range of m.

  In addition, when the photocurable ink composition for inkjet recording contains a pigment, a dispersant or a surfactant can be included in order to obtain good dispersion of the pigment. As a preferable dispersant, a dispersant conventionally used for preparing a pigment dispersion, for example, a polymer dispersant can be used. Specific examples of the polymer dispersant include polyoxyalkylene polyalkylene polyamine. Specific examples of the polyoxyalkylene polyalkylene polyamine include, for example, Discole N-503, N-506, N-509, N-512, N-515, N-518, N-520 (Daiichi Kogyo). Pharmaceutical Co., Ltd.).

  When the above-described color material is contained in the photocurable ink composition for inkjet recording, the metallic glossy surface can be colored, and the expressive power of the recorded matter can be enhanced.

  The photocurable ink composition for inkjet recording can further contain a polymerization accelerator. The polymerization accelerator that can be used in the photocurable ink composition for inkjet recording is not particularly limited, and examples thereof include Darocur EHA, EDB (available from Ciba Specialty Chemicals).

  Moreover, the photocurable ink composition for inkjet recording can also contain a hindered amine compound as a thermal radical polymerization inhibitor. By containing a hindered amine compound, the storage stability of the photocurable ink composition for inkjet recording can be improved. As the hindered amine compound, a compound having a 2,2,6,6-tetramethylpiperidine group in the structure is particularly preferable. Such hindered amine compounds include 2,2,6,6-tetramethylpiperidinooxy, free radicals, bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, etc. Is mentioned. Examples of commercially available compounds having a 2,2,6,6-tetramethylpiperidine group in the structure include Irgastab UV-10 (available from Ciba Specialty Chemicals). When the thermal radical polymerization inhibitor is blended with the photocurable ink composition for inkjet recording, the blending amount is preferably 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass.

  Furthermore, the photocurable ink composition for ink jet recording can contain a surfactant in order to improve storage stability and the like. As the surfactant, for example, polyester-modified silicone or polyether-modified silicone can be used as a silicone-based surfactant, and it is particularly preferable to use polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane. Specific examples include BYK-347, BYK-348, BYK-UV3500, -UV3510, -UV3530, and -UV3570 (available from Big Chemie Japan KK).

  Moreover, the viscosity of the photocurable ink composition for inkjet recording can be adjusted by adjusting the blending amount of each of the above components. The viscosity of the photocurable ink composition for inkjet recording can be adjusted to be suitable for the inkjet recording apparatus by adjusting the viscosity. A preferable viscosity range of the photocurable ink composition for inkjet recording is 2.0 to 20 (mPa · s) at 20 ° C. If it is out of this range, the ink jet recording apparatus may not be able to discharge easily.

The photocurable ink composition for inkjet recording of the present embodiment described above includes a metal pigment composed of tabular particles in which a metal or alloy layer and at least one selected from a resin layer and a silicon oxide layer are laminated. contains. Therefore, since the normal direction of the tabular grains is aligned with the normal direction of the recording medium on the recording medium, it is possible to form a printed surface having a high gloss metallic gloss surface on the recording medium. it can. Furthermore, since the photocurable ink composition for ink-jet recording of the present embodiment contains a metal pigment composed of tabular grains, the photopolymerization of the polymerizable compound in the printed surface can sufficiently proceed. And thereby, the photocurable ink composition for inkjet recording of this embodiment can be applied suitably for the inkjet recording method.

2. Inkjet recording method As an inkjet recording method according to the present embodiment, the above-described photocurable ink composition for inkjet recording is ejected onto a recording medium and adhered onto the recording medium to form a printing surface. Illustrated are those that irradiate ultraviolet rays as light.

  In the ink jet recording method according to the present embodiment, a photocurable ink composition for ink jet recording is discharged onto a recording medium using an ink jet recording apparatus. The ink jet recording apparatus used in the present embodiment is not particularly limited as long as it can record information by discharging ink droplets and attaching the droplets to a recording medium.

  As a recording method of an ink jet recording apparatus, for example, a strong electric field is applied between a nozzle and an acceleration electrode placed in front of the nozzle, and ink is continuously ejected from the nozzle in the form of droplets. A method in which a print information signal is applied to a polarizing electrode for recording while flying or a method in which ink droplets are ejected in response to a print information signal without being deflected (electrostatic suction method). In addition, a system that forcibly ejects ink droplets by mechanically vibrating the nozzle with a crystal resonator, etc., a system that simultaneously applies pressure and printing information signals to ink liquid with piezoelectric elements, and ejects and records ink droplets (Piezo method), a method in which an ink liquid is heated and foamed with a microelectrode according to a print information signal, and an ink droplet is ejected and recorded (thermal jet method).

  Examples of the ink jet recording apparatus include an ink jet recording head, a main body, a tray, a head driving mechanism, a carriage, and an ultraviolet irradiation device mounted on a side surface of the carriage. The ink jet recording head includes at least four ink cartridges of cyan, magenta, yellow, and black, and is configured to perform full color printing. The at least one ink cartridge is filled with the photocurable ink composition for ink jet recording according to the present embodiment and installed. In addition, this ink jet recording apparatus includes a dedicated control board and the like, and can control the ink ejection timing of the ink jet recording head and the scanning of the head driving mechanism.

For the irradiation of ultraviolet rays, an ultraviolet irradiation device mounted on the side surface of the carriage in the ink jet recording apparatus can be applied. The wavelength of the irradiation light source is not particularly limited, but is preferably 350 nm or more and 450 nm or less. A light irradiation amount is preferably 10 mJ / cm ² or more and 20000 mJ / cm ² or less, more preferably 50 mJ / cm ² or more, conducted at 15,000 mJ / cm ² or less. If it is the ultraviolet irradiation amount in this range, the curing reaction of the printing surface of the photocurable ink composition for ink jet recording formed on the recording medium can be sufficiently performed.

In addition to the ultraviolet irradiation method, light such as a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low pressure mercury lamp, and a high pressure mercury lamp may be guided to the printing surface by a light guide or the like. Moreover, as a light source, it can carry out using what was marketed, such as H lamp, D lamp, and V lamp which can be obtained from Fusion System etc., for example. Further, as the light source, an ultraviolet light emitting semiconductor element such as an ultraviolet light emitting diode (ultraviolet LED) or an ultraviolet light emitting semiconductor laser can be used, and ultraviolet light from such a light source can be irradiated.

  The ultraviolet irradiation may be performed in the apparatus using the ink jet recording apparatus as exemplified above, or after forming the printing surface by the ink jet recording apparatus not equipped with the ultraviolet irradiation apparatus, another ultraviolet irradiation apparatus is used. May be used.

  The recording medium that can be used in the ink jet recording method of the present embodiment is arbitrary as long as the ink composition can be attached by an ink jet recording apparatus. Examples of the recording medium include non-absorbing recording media such as metal, glass, and plastic, and absorbent recording media such as paper, film, and cloth. Further, the recording medium may be colorless and transparent, translucent, colored and transparent, chromatic color opaque, achromatic color opaque, and the like.

  The ink jet recording method of the present embodiment can also be applied to manufacturing processes for industrial products such as color filter creation and marking on a printed circuit board.

  According to the ink jet recording method as described above, since the photocurable ink composition for ink jet recording contains a metal pigment composed of tabular grains, a printing surface having a high gloss metal gloss surface is formed on a recording medium. can do. Furthermore, since the photocurable ink composition for ink jet recording contains a metal pigment composed of tabular particles, the curing reaction of the polymerizable compound in the printed surface can be sufficiently advanced.

3. Recorded matter Since the recorded matter obtained by the ink jet recording method according to the present embodiment is formed using the above-described photocurable ink composition for ink jet recording, it has a metallic glossy surface with high glossiness. Furthermore, since the photocurable ink composition for ink jet recording contains a metal pigment composed of tabular particles, the curing reaction of the polymerizable compound in the printed surface has sufficiently progressed.

4). Ink Set As an ink set according to this embodiment, an ink set including at least one ink containing the above-described photocurable ink composition for inkjet recording is exemplified.

  An ink set including one or a plurality of inks each including the above-described photocurable ink composition for ink jet recording may be used, or an ink set including an ink including one or more other ink compositions may be used. Other ink compositions that can be provided in the ink set for inkjet recording include cyan, magenta, yellow, light cyan, light magenta, dark yellow, red, green, blue, orange, violet and other color ink compositions, black ink Examples thereof include a composition and a light black ink composition.

5. Ink Cartridge and Inkjet Recording Device As an ink cartridge according to the present embodiment, an ink cartridge provided with the above ink set is exemplified. According to this, the ink set provided with said photocurable ink composition for inkjet recording can be conveyed easily. An ink jet recording apparatus according to this embodiment includes the above-described photocurable ink composition for ink jet recording, an ink set for ink jet recording, or an ink cartridge. For example, the ink jet recording apparatus described in the section of the ink jet recording method described above. A recording apparatus can be exemplified.

6). Examples, Reference Examples and Comparative Examples The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is of course not limited by these examples.

6.1. Examples and Reference Examples 6.1.1. Preparation of composite pigment A and dispersion stock solution of composite pigment A 6.1.1.1. Formation of Release Layer The following coating solution was applied and dried on a 100 μm-thick PET film by a spin coating method to form a release layer.

(Release layer coating solution)
As the release layer coating solution, a solution obtained by dissolving PVA (polyvinyl alcohol, average molecular weight 10,000, saponification degree 80%) in 3.3% by mass and glycerin in ion-exchanged water to 1.7% by mass was used. .

(Release layer coating conditions)
A release layer coating solution was applied onto the above-described PET film by a spin coating method. As coating conditions, a release layer coating solution was dropped onto a PET film on a turntable, rotated at 500 rpm for 5 seconds, and then rotated at 2000 rpm for 30 seconds. Then, the drying process for 5 minutes was performed at 100 degreeC. The thickness of the release layer formed under these conditions was 10 μm.

6.1.1.2. Formation of pigment layer <Formation of silicon oxide layer>
On the PET film having a release layer formed on the surface by the above method, the following coating solution was applied and baked by a spin coating method to form a silicon oxide layer.

(Silicon oxide layer coating solution)
As the silicon oxide layer coating solution, a mixed solution in which HAS-6 (manufactured by Colcoat Co., Ltd.) was mixed by 10% by mass, ethanol by 42.5% by mass, and 2-ethoxyethanol by 47.5% by mass was used.

(Silicon oxide layer coating conditions)
A silicon oxide layer coating solution was applied onto the release layer on the PET film by spin coating. As the coating conditions, the above silicon oxide layer coating solution was dropped on the release layer on the PET film on the turntable, rotated at 500 rpm for 5 seconds, and then rotated at 2000 rpm for 30 seconds. Thereafter, a baking treatment was performed at 140 ° C. for 5 minutes. The thickness of the silicon oxide layer formed under these conditions was 70 nm.

<Formation of color material layer>
(Coloring material layer coating solution)
A color material layer coating solution was prepared. The color material layer coating solution contains C.I. I. Pigment Yellow 110 (coloring material) is 15.0% by mass, and as a dispersant, styrene-acrylic acid copolymer / ammonium salt (molecular weight 10,000) is 5.0% by mass, and glycerin is 5.0% by mass. Each component was blended with ion exchange water.

  As a method for preparing the color material layer coating liquid, a color material, a dispersant, and ion-exchanged water are mixed, and glass beads (1.7 mm in diameter, 1.5 of the mixture) are mixed in a sand mill (manufactured by Yaskawa Seisakusho). Double amount (weight)) for 2 hours, and then the glass beads were removed.

(Coloring material layer coating conditions)
The prepared color material layer coating solution was applied and dried on the silicon oxide layer by a spin coating method to form a color material layer having a thickness of 150 nm.

<Formation of aluminum layer>
The aluminum layer was formed by vapor-depositing aluminum having a film thickness of 70 nm on the above-described color material layer using a VE-1010 type vacuum vapor deposition apparatus manufactured by Vacuum Device Co., Ltd.

<Formation of color material layer>
Similar to the formation of the color material layer described above, a color material layer was formed on the aluminum layer. The thickness of the formed color material layer was also 150 nm.

<Formation of silicon oxide layer>
In the same manner as the formation of the silicon oxide layer described above, a silicon oxide layer was formed on the color material layer. The thickness of the formed silicon oxide layer was 70 nm.

6.1.1.3. Properties of base material of composite pigment A As described above, the structure of the release layer and the pigment layer (silicon oxide layer / color material layer / aluminum layer / color material layer / silicon oxide layer) on the sheet-like substrate. The raw material of the composite pigment A which has this was produced. When the raw material of this composite pigment A was observed visually, it showed a golden color.

6.1.1.4. Peeling and crushing / dispersing treatment A PET film having a laminate of peeling layer-silicon oxide layer-coloring material layer-aluminum layer-coloring material layer-silicon oxide layer formed by the above-described method, in ethylene glycol monoallyl ether, Stripping, miniaturization, and dispersion treatment were simultaneously performed using an ultrasonic disperser.

  As described above, a dispersion stock solution of the composite pigment A and the composite pigment A containing the composite pigment A was prepared. The composite pigment A corresponds to the composite pigment of the third form described in the embodiment section.

6.1.2. Preparation of Compound Pigment B and Dispersion Stock Solution of Compound Pigment B 6.1.2.1. Formation of Release Layer The following coating solution was applied and dried on a 100 μm-thick PET film by a spin coating method to form a release layer.

(Release layer coating solution)
As a release layer coating solution, a solution prepared by dissolving Esletk BL-10 (Sekisui Chemical Co., Ltd. butyral resin) in 3.3% by mass and glycerin in 2.0% by mass in IPA (isopropyl alcohol). Using.

(Release layer coating conditions)
A release layer coating solution was applied onto the above-described PET film by a spin coating method. As coating conditions, a release layer coating solution was dropped onto a PET film on a turntable, rotated at 500 rpm for 5 seconds, and then rotated at 2000 rpm for 30 seconds. Then, the drying process for 5 minutes was performed at 100 degreeC. The thickness of the release layer formed under these conditions was 10 μm.

6.1.2.2. Formation of pigment layer <Formation of resin layer>
On the PET film having a release layer formed on the surface by the above method, the following coating solution was applied and dried by a spin coating method to form a resin layer.

(Resin layer coating solution)
As the release layer coating solution, a solution obtained by dissolving PVA (polyvinyl alcohol, average molecular weight 10,000, saponification degree 80%) in 3.3% by mass and glycerin in ion-exchanged water to 1.7% by mass was used. .

(Resin layer coating conditions)
A resin layer coating solution was applied onto the release layer on the PET film by spin coating. As the coating conditions, the above resin layer coating solution was dropped on the release layer on the PET film on the turntable, rotated at 500 rpm for 5 seconds, and then rotated at 2000 rpm for 30 seconds. Then, the drying process for 5 minutes was performed at 100 degreeC. The thickness of the resin layer formed under these conditions was 10 μm.

<Formation of color material layer>
(Coloring material layer coating solution)
A color material layer coating solution was prepared. The color material layer coating solution contains C.I. I. Pigment Yellow 110 (coloring material) is 15.0% by mass, and as a dispersant, Esletk BL-10 (Butyral resin manufactured by Sekisui Chemical Co., Ltd.) is 5.0% by mass, and glycerin is 5.0% by mass. Each component was blended with IPA (isopropyl alcohol).

  As a method for preparing the color material layer coating solution, a color material, a dispersant, and IPA are mixed, and in a sand mill (manufactured by Yaskawa Seisakusho), glass beads (1.7 mm in diameter, 1.5 times the amount of the mixture) (Weight)) for 2 hours, and then the glass beads were removed.

(Coloring material layer coating conditions)
The prepared color material layer coating solution was applied and dried on the resin layer by a spin coating method to form a color material layer having a thickness of 150 nm.

<Formation of aluminum layer>
The aluminum layer was formed by vapor-depositing aluminum having a film thickness of 70 nm on the above-described color material layer using a VE-1010 type vacuum vapor deposition apparatus manufactured by Vacuum Device Co., Ltd.

<Formation of color material layer>
Similar to the formation of the color material layer described above, a color material layer was formed on the aluminum layer. The thickness of the formed color material layer was also 150 nm.

<Formation of resin layer>
A resin layer was formed on the color material layer in the same manner as the resin layer formation described above. The thickness of the formed resin layer was 10 μm.

6.1.2.3. Properties of the base material of the composite pigment B As described above, the release layer and the pigment layer (resin layer / color material layer / aluminum layer / color material layer / resin layer) are formed on the sheet-like substrate. A base material of composite pigment B was prepared. When the raw material of this composite pigment B was observed visually, it showed a golden color.

6.1.2.4. Peeling and crushing / dispersing treatment A PET film having a laminate of release layer-resin layer-coloring material layer-aluminum layer-coloring material layer-resin layer formed by the above method was ultrasonicated in ethylene glycol monoallyl ether. Using a disperser, peeling, miniaturization, and dispersion treatment were simultaneously performed. Then, about 1 mL of 0.4 mass% AG solution of citric acid in the dispersion was added and reacted at 60 ° C. for 4 hours.

  As described above, composite pigment B and a dispersion stock solution of composite pigment B containing the composite pigment B were prepared. The composite pigment B corresponds to the composite pigment of the fourth form described in the embodiment section.

6.1.3. Preparation of Photocurable Ink Composition for Inkjet Recording Each of the dispersion liquids of composite pigment A and composite pigment B obtained as described above is subjected to filtration with a SUS mesh filter having an opening of 5 μm to obtain coarse particles. Was removed. Subsequently, the filtrate was put into a round bottom flask, and excess ethylene glycol monoallyl ether was distilled off using a rotary evaporator. Thereby, each dispersion undiluted solution is concentrated, and for each of the concentrated solutions, using a thermal analyzer (EXSTAR-6000TG / DTA manufactured by SII NanoTechnology Co., Ltd.) The content (concentration) of the metal pigment in the pigment dispersion was adjusted to obtain a metal pigment dispersion A and a metal pigment dispersion B having a concentration of 5% by mass.

  Then, using a particle diameter / particle size distribution measuring apparatus (FPIA-3000S manufactured by Sysmex Corporation), the 50% average particle diameter R50 in the circle equivalent diameter of the X (major axis) Y (minor axis) plane of the metal pigment is measured. R50 / Z was calculated based on the measured values of R50 and Z (thickness) obtained.

  As a result, the metal pigment of this example had values of R50 = 1.03 μm and R50 / Z = 51.5.

  Using the metal pigment dispersion A and the metal pigment dispersion B prepared by the above method, photocurable ink compositions for inkjet recording of each Example and each Reference Example were prepared with the compositions shown below. Hereinafter, the blending amount is shown by mass%.

<Example 1>
Complex pigment dispersion A (solid content conversion): 1.0%
Cyracure UVI-6692 (polymerization initiator, manufactured by Dow Chemical Company): 5.0%
Cyracure UVR-6105 (oligomer, manufactured by Dow Chemical Co.): 10.0%
BYK-UV3570 (polyester-modified silicone surfactant, manufactured by BYK Japan KK): 0.5%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (polymerizable compound, manufactured by Toagosei Co., Ltd.): residue <Example 2>
Complex pigment dispersion B (solid content conversion): 1.0%
Cyracure UVI-6692: 5.0%
Cyracure UVR-6105: 10.0%
BYK-UV3570: 0.5%
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane: residue <Reference Example 1>
Complex pigment dispersion A (solid content conversion): 1.0%
Biscote # 1000 (polymerizable compound, manufactured by Osaka Organic Chemical Industry Co., Ltd.): 25%
Irgacure 819 (polymerization initiator, manufactured by Ciba Specialty Chemicals): 3.4%
Irgacure 127 (polymerization initiator, manufactured by Ciba Specialty Chemicals): 1.6%
BYK-UV3570: 0.2%
Irgastab UV-10 (thermal radical polymerization inhibitor, manufactured by Ciba Specialty Chemicals): 0.2%
Ethylene glycol monoallyl ether (polymerizable compound, manufactured by Osaka Organic Chemical Industry Co., Ltd.): residue <Reference Example 2>
Composite pigment dispersion B (solid content conversion): 1.0%
Biscote # 1000: 25%
Irgacure 819: 3.4%
Irgacure 127: 1.6%
BYK-UV3570: 0.2%
Irgastab UV-10: 0.2%
Ethylene glycol monoallyl ether: residue After mixing and dissolving each substance other than the above metal pigment, the metal pigment dispersion A or the metal pigment dispersion B prepared by the above method is added, and further at room temperature and normal pressure It mixed and stirred for 120 minutes with the magnetic stirrer, and it was set as the photocurable ink composition for inkjet recording of Example 1, 2 and the reference examples 1 and 2. FIG.

6.2. Comparative Example In the comparative example, an ink composition containing metal particles having no flat shape as a metal pigment was used. As the metal pigment of the comparative example, aluminum particles contained in a commercially available aluminum paste (manufactured by Toyo Aluminum Co., Ltd .: WXM0650) were used. The metal particles of the comparative example have a spherical shape and have an average particle diameter of 6 μm.

  The ink composition of the comparative example was the same as in Example 1 except that the metal pigment was aluminum particles having no laminated flat plate shape as described above. It produced similarly.

6.3. Preparation of evaluation sample 6.3.1. Cured product of ink composition The ink compositions of Examples, Reference Examples and Comparative Examples were dropped onto a glass substrate. Thereafter, the respective compositions were cured using a UV irradiation light source under curing conditions such that the integrated light amount at a wavelength of 365 nm was 1000 mJ / cm ² , and the ink compositions of the Examples, Reference Examples and Comparative Examples were used. A cured product was obtained.

6.3.2. Recorded matter by ink jet recording method G. The ink composition of each example was introduced into the black row of an inkjet printer SV300V manufactured by Corporation. Then, each ink composition was printed on a recording medium (vinyl chloride sheet (SPVC-G-1270T manufactured by Roland DG Co., Ltd.) cut to A4 size. Printing was performed by solid printing of 10 cm × 10 cm. The amount of ink used was 0.9 mg / cm ² .

The obtained solid pattern is cured under curing conditions such that the integrated light quantity at a wavelength of 365 nm is 1000 mJ / cm ² by an ultraviolet irradiation device installed at the discharge port of the ink jet printer, thereby obtaining the recorded matter of each example. It was.

For the ink composition of the comparative example, solid pattern printing was attempted in the same manner as in the example, but printing with an inkjet printer was not possible. Accordingly, bar coat printing was performed using a wire bar (# 3 wire bar manufactured by RK PrintCoat Instrument Ltd.) so that the ink coat amount was 0.9 mg / cm ² to obtain a recorded matter of a comparative example.

6.4. Evaluation of Cured Material and Recorded Material A finger touch test was performed on the cured material of each Example, Reference Example, and Comparative Example prepared in “6.3.1. Cured Material of Ink Composition”. As a result, it was found that the cured products of each Example and Reference Example were not cured with any tackiness and were cured well. On the other hand, the cured product of the comparative example was found to be tacky and insufficiently cured.

  Each of the recorded materials of Examples, Reference Examples, and Comparative Examples prepared in “6.3.2. Recorded materials by inkjet recording method” was visually observed to evaluate the surface. The recorded materials of the examples all showed good metallic luster. On the other hand, the recorded material of the comparative example was inferior in metallic gloss to the examples.

  As described above, the photocurable ink composition for ink-jet recording according to each of the examples and the reference examples contains a composite pigment having a structure in which a metal or alloy layer is covered with a silicon oxide layer or a resin layer, respectively. ing. For this reason, it has been found that a printing surface having a metallic glossy surface having a high glossiness can be formed on a recording medium. Furthermore, it was found that the photocurable ink compositions for ink jet recording in each of Examples and Reference Examples can sufficiently advance the photopolymerization of the polymerizable compound in the printing surface by light irradiation. It has been found that any of the photocurable ink compositions for ink-jet recording of the examples and reference examples can be sufficiently applied to the ink-jet recording method.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (8)

Metal pigments,
A cationically polymerizable compound;
A polymerization initiator;
Containing
The metal pigment is
A metal or alloy layer;
At least one selected from a resin layer and a silicon oxide layer;
Are laminated tabular grains,
The end face of the metal or alloy layer is formed by chemical conversion treatment with at least one chemical oxidant selected from the group consisting of hydrogen peroxide, chromic acid, phosphoric acid, phosphate, citric acid, and malic acid. A photocurable ink composition for inkjet recording. In claim 1,
The metal pigment is for inkjet recording, wherein at least one selected from the resin layer and the silicon oxide layer, at least one selected from the metal or alloy layer, and the resin layer and the silicon oxide layer are sequentially laminated. A photocurable ink composition. In claim 1 or claim 2,
A photocurable ink composition for inkjet recording, further comprising a color material layer between the metal or alloy layer and at least one selected from the resin layer or the silicon oxide layer in the metal pigment. In any one of Claims 1 thru | or 3,
The tabular grains are 50% average grains in a circle-equivalent diameter determined from the area of the XY plane of the tabular grains when the major axis on the plane of the tabular grains is X, the minor axis is Y, and the thickness is Z. A photocurable ink composition for ink jet recording, having a diameter R50 of 0.5 to 3 μm and a shape satisfying a condition of R50 / Z> 5. In any one of Claims 1 thru | or 4,
The photocurable ink composition for ink jet recording, wherein the metal or alloy layer is made of aluminum or an aluminum alloy. In any one of Claims 1 thru | or 5,
The photocurable ink composition for inkjet recording, wherein a light transmittance of a wavelength of 350 nm or more and 450 nm or less with respect to a thickness direction of the metal or alloy layer is 0.5% or more. In any one of Claims 1 thru | or 6,
The photocurable ink composition for inkjet recording, wherein the metal pigment has a thickness of 100 nm to 500 nm. In any one of Claims 1 thru | or 7,
The photo-curable ink composition for ink jet recording, wherein the cationic polymerizable compound is an oxetane compound.