JP2020193302A - Inkjet ink, printed matter, and production method of printed matter - Google Patents

Abstract

To provide an inkjet ink with which a printed matter can be obtained that can express a delicate image or a thick raised image, can follow a large deformation of a base material and less likely causes cracks, a printed matter and a production method of a printed matter.SOLUTION: The inkjet ink comprises an ultraviolet ray-curable oligomer, a photopolymerization initiator, and an organic solvent. The inkjet ink shows a viscosity of 5 to 20 mPa s at 50°C, and the ultraviolet ray-curable oligomer shows a viscosity of 20,000 mPa s or more at 60°C.SELECTED DRAWING: None

Description

The present invention relates to ink for inkjet, printed matter, and a method for manufacturing a printed matter. More specifically, the present invention is capable of delicate image expression and thick expression, can follow large deformation of the base material, and can obtain a printed matter that is less likely to crack. Ink, printed matter and method of manufacturing printed matter.

Conventionally, an inkjet ink for forming an image on a base material by an inkjet method has been developed. The obtained printed matter is subjected to processing such as deformation depending on the intended use. Patent Document 1 discloses an ultraviolet curable ink containing a reactive diluent which is a monomer and for recording an image on a flexible substrate. Further, Patent Document 2 discloses a printing ink containing a low-viscosity oligomer and for forming a delicate image.

Japanese Unexamined Patent Publication No. 2004-131725 Special Table 2013-502480

However, in recent years, due to improvements in the base material and the like, the base material may be subjected to greater deformation. Further, in order to express an image three-dimensionally, there is a technique (thickening expression) of applying ink for inkjet so that the height of the inkjet image layer (thickness of the inkjet image layer) is increased. The ultraviolet curable ink described in Patent Document 1 cannot sufficiently follow the base material when a large deformation is applied to the base material or when a thick layer is expressed, and the inkjet image layer is cracked. In some cases. Further, the printing ink described in Patent Document 2 remains highly fluid even when the solvent is dried after applying the ink, and it is difficult to perform delicate image expression and thickening expression.

The present invention has been made to solve the above problems, and is capable of delicate image expression and thick expression, can follow large deformation of the base material, and is less likely to cause cracking. It is an object of the present invention to provide an ink for inkjet, a printed matter, and a method for producing a printed matter, which can obtain a product.

As a result of diligent studies on a method for performing delicate image expression and thick expression and for preventing cracks in the inkjet image layer in the obtained printed matter, the present inventor has obtained an ultraviolet curable oligomer having a specific viscosity. We have found that by using it, it is possible to express a delicate image and a thick image, it is possible to follow a large deformation of a base material, and it is possible to obtain a printed matter which is less likely to be cracked. It was completed.

The method for producing an inkjet ink, a printed matter, and a printed matter of the present invention that solves the above problems mainly includes the following configurations.

(1) An inkjet ink containing an ultraviolet curable oligomer, a photopolymerization initiator, and an organic solvent. The inkjet ink has a viscosity at 50 ° C. of 5 to 20 mPa · s, and the ultraviolet curable oligomer. Ink for inkjet, which has a viscosity of 20,000 mPa · s or more at 60 ° C.

According to such a configuration, the inkjet ink contains an ultraviolet curable oligomer having a viscosity at 60 ° C. of 20,000 mPa · s or more. When such an inkjet ink is applied to a base material and then dried, the viscosity of the ink increases rapidly, and it becomes difficult for the ink to spread on the base material. As a result, the inkjet ink can easily perform delicate image expression and thick expression. In addition, the UV-curable oligomer has a smaller number of cross-linking points during curing than the UV-curable monomer. Therefore, the obtained inkjet image layer is flexible, can follow large deformation of the base material, and is less likely to crack.

(2) The inkjet ink according to (1), wherein the content of the ultraviolet curable oligomer is 20 to 50% by mass in the inkjet ink.

According to such a configuration, the inkjet ink maintains an appropriate viscosity as the inkjet ink and contains a large amount of solid content, so that it is easier to express a thick layer.

(3) The inkjet ink according to (1) or (2), which further contains an ultraviolet curable monomer.

According to such a configuration, the inkjet ink maintains an appropriate viscosity as the inkjet ink and contains a large amount of solid content, so that it is easier to express a thick layer.

(4) The inkjet ink according to (3), wherein the content of the ultraviolet curable monomer is 0.4 times or less the content of the ultraviolet curable oligomer in terms of mass ratio.

According to such a configuration, it is easy to appropriately adjust the rate at which the viscosity of such an inkjet ink increases by being applied to a substrate and then dried. As a result, the inkjet ink is more likely to perform delicate image expression and thick expression.

(5) The inkjet ink according to any one of (1) to (4), wherein the organic solvent has a boiling point of 150 to 250 ° C.

According to such a configuration, the inkjet ink does not easily dry the inkjet nozzle of the inkjet recording device, and has excellent ejection stability. Further, in the inkjet ink applied to the base material, the solvent easily volatilizes, and it is easy to perform more delicate image expression.

(6) The inkjet ink according to any one of (1) to (5), further containing a coloring pigment, wherein the content of the coloring pigment is 5% by mass or less in the inkjet ink.

According to such a configuration, the inkjet ink does not deteriorate the ejection stability, and it is easy to sufficiently color the obtained printed matter.

(7) A printed matter comprising a base material and an inkjet image layer formed on the base material by the inkjet ink according to any one of (1) to (6).

According to such a configuration, the printed matter can be expressed in a delicate image or a thick image. Further, the inkjet image layer formed on the printed matter is flexible, can follow a large deformation of the base material, and is less likely to be cracked.

(8) An inkjet step of forming an image on a substrate by an inkjet method using the inkjet ink according to any one of (1) to (6), a volatilization step of volatilizing the organic solvent, and ultraviolet rays. A method for producing a printed matter, which includes a curing step of irradiating and curing the ink for an inkjet.

With such a configuration, it is possible to obtain a printed matter in which a delicate image expression and a thick expression are performed. Further, the inkjet image layer formed on the printed matter is flexible, can follow a large deformation of the base material, and is less likely to be cracked.

According to the present invention, it is possible to express a delicate image or a thick image, it is possible to follow a large deformation of a base material, and it is possible to obtain a printed matter which is less likely to be cracked. It is possible to provide a method for producing an article and a printed matter.

<Ink for Ink>
The inkjet ink (hereinafter, also referred to as ink) of one embodiment of the present invention contains an ultraviolet curable oligomer, a photopolymerization initiator, and an organic solvent. The viscosity of the ink at 50 ° C. is 5 to 20 mPa · s. The viscosity of the UV curable oligomer at 60 ° C. is 20,000 mPa · s or more. When the ink is applied to the base material and then dried, the viscosity of the ink rapidly increases, and it becomes difficult for the ink to wet and spread on the base material. As a result, the ink is easy to perform delicate image expression and thick expression. In addition, the UV-curable oligomer has a smaller number of cross-linking points during curing than the UV-curable monomer. Therefore, the obtained inkjet image layer is flexible, can follow large deformation of the base material, and is less likely to crack. Each will be described below.

(UV curable oligomer)
The ultraviolet curable oligomer is not particularly limited. As an example, the ultraviolet curable oligomer is a urethane-based, acrylic-based, polycarbonate-based, epoxy-based, polyether-based, polyester-based ultraviolet-curable oligomer or the like having two or more photopolymerizable functional groups in one molecule. Is. The UV curable oligomer may be used in combination. By using these oligomers, the obtained inkjet image layer exhibits high film strength. In the present embodiment, the oligomer is a plurality of polymers of monomers and has a weight average molecular weight of 1,000 to 30,000. In this embodiment, the weight average molecular weight (Mw) is gel permeation chromatography (HLC-8020GPC, manufactured by Toso Co., Ltd.), the sample concentration is 0.45% by mass, and the flow velocity is 0.35 ml / min. , The sample injection amount is 10 μl, the measurement temperature is 40 ° C., and the measurement can be performed using a differential refractometer detector.

The polyfunctional urethane-based oligomer is obtained by reacting a polyol with an organic polyisocyanate to prepare a urethane prepolymer, and reacting the urethane prepolymer with a hydroxyl group-containing (meth) acrylate. Further, the urethane-based oligomer may be one obtained by reacting an organic polyisocyanate with a hydroxyl group-containing (meth) acrylate. By using such a urethane-based oligomer, the elasticity of the obtained inkjet image layer is improved.

Polyols are ethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 1,6-hexanediol, polypropylene glycol, bisphenol A polyethylene glycol, polytetramethylene glycol, glycerin, trimethylolpropane, polyester polyol, polycarbonate. Polyols, polycaprolactone polyols, polybutadiene polyols, polymer polyols, polysiloxane polyols and the like.

Organic polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate or diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as tetramethylxylylene diisocyanate, isophorone diisocyanates, bis (4-isocyanate cyclohexyl) methane, hexamethylene diisocyanates, and trimethylhexamethylene. It is an aliphatic or cyclic aliphatic diisocyanate such as diisocyanate. Further, the organic polyisocyanate may be various modified products such as urethane-modified, carbodiimide-modified, biuret-modified, and isocyanurate-modified.

The hydroxyl group-containing (meth) acrylate is a monofunctional (meth) acrylate having one acrylic group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , Trimethylol propandi (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and other polyfunctional (meth) acrylates having two or more acrylic groups. Is.

Acrylic-based oligomers are polymers of alkyl (meth) acrylates such as (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Contains the above monomer and vinyl carboxylic acid compounds such as maleic acid, itaconic acid, crotonic acid and fumaric acid, glycidyl groups such as glycidyl (meth) acrylate, allyl glycidyl ether, glycidyl ethylacrylate, crotonyl glycidyl ether and glycidyl crotonate. It is a copolymer with a compound selected from a vinyl compound, hydroxyethyl (meth) acrylate, vinyl acetate, (meth) acrylonitrile, (meth) acrylic acid chloride, N- (meth) acryloylmorpholine and the like.

The polycarbonate-based oligomer is an oligomer obtained by reacting a polycarbonate polyol, a polyisocyanate, and an ethylenically unsaturated monomer having a hydroxy functional group.

The epoxy-based oligomer is an epoxy-based oligomer obtained by reacting an epoxy resin with an acrylate.

The polyether oligomer is an ester of polypropylene glycol and acrylic acid.

The polyester-based oligomer is an ester of acrylic acid and a polyester diol composed of adipic acid and 1,6-hexanediol.

Among these, the ultraviolet curable oligomer is preferably a urethane-based oligomer from the viewpoint of excellent flexibility of the film after curing.

The ultraviolet curable oligomer of the present embodiment has a viscosity at 60 ° C. of 20,000 mPa · s or more, preferably 21,000 mPa · s or more, and more preferably 23,000 mPa · s or more. When the viscosity at 60 ° C. is within the above range, the ink is dried after being applied to the base material, so that the viscosity rapidly increases and it becomes difficult for the ink to wet and spread on the base material. As a result, the inkjet ink can easily perform delicate image expression and thick expression. The viscosity of the ultraviolet curable oligomer can be measured using, for example, a B-type viscometer (TVB-20LT, manufactured by Toki Sangyo Co., Ltd.).

The number average molecular weight (Mn) of the ultraviolet curable oligomer is not particularly limited. As an example, the Mn of the ultraviolet curable oligomer is preferably 1,000 or more, and more preferably 3,000 or more. The Mn of the ultraviolet curable oligomer is preferably 30,000 or less, and more preferably 25,000 or less. When the Mn of the ultraviolet curable oligomer is within the above range, the ink is dried after being applied to the base material, so that the viscosity of the ink rapidly increases and it becomes difficult for the ink to spread on the base material. As a result, the inkjet ink can easily perform delicate image expression and thick expression. The Mn of the ultraviolet curable oligomer can be calculated by using, for example, gel permeation chromatography (HLC-8220, manufactured by Tosoh Corporation) and using a polystyrene standard.

The content of the ultraviolet curable oligomer is not particularly limited. As an example, the content of the ultraviolet curable oligomer is preferably 20% by mass or more, and more preferably 25% by mass or more in the ink. The content of the ultraviolet curable oligomer is preferably 50% by mass or less, and more preferably 40% by mass or less in the ink. When the content of the ultraviolet curable oligomer is within the above range, the ink maintains an appropriate viscosity as an ink for an inkjet and contains a large amount of solid content, so that it is easier to express a thick ink.

(Photopolymerization initiator)
A photopolymerization initiator is included to moderately cure the ink with ultraviolet light. The photopolymerization initiator is not particularly limited. For example, the photopolymerization initiator is an alkylphenone-based compound, a benzophenone-based compound, a benzoin-based compound, a thioxanthone-based compound, a halomethylated triazine-based compound, a halomethylated oxadiazole-based compound, a biimidazole-based compound, or an oxime ester-based compound. These include compounds, titanosen compounds, benzoic acid ester compounds, aclysin compounds and the like. The photopolymerization initiator may be used in combination.

The alkylphenone-based compound is not particularly limited. As an example, alkylphenone compounds include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropane-. 1-on, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy) -2-Methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethyl Amino-1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1- Butanon etc.

The benzophenone compound is not particularly limited. For example, benzophenone compounds include benzophenone, 4,4'-bis (dimethylamino) benzophenone, 2-carboxybenzophenone and the like.

The benzoin compound is not particularly limited. For example, the benzoin compound is benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and the like.

The thioxanthone compound is not particularly limited. For example, the thioxanthone-based compound is thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone and the like.

The halomethylated triazine compound is not particularly limited. For example, halomethylated triazine compounds are 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -sec-triazine, 2- (4-methoxynaphthyl) -4,6-bis ( Trichloromethyl) -sec-triazine, 2- (4-ethoxynaphthyl) -4,6-bis (trichloromethyl) -sec-triazine, 2- (4-ethoxycarbokynylnaphthyl) -4,6-bis (trichloromethyl) ) -Se-triazine and the like.

The halomethylated oxadiazole-based compound is not particularly limited. For example, the halomethylated oxadiazole compounds are 2-trichloromethyl-5-[β- (2'-benzofuryl) vinyl] -1,3,4-oxadiazole, 2-trichloromethyl-5-. [Β- (2'-(6 "-benzofuryl) vinyl)] -1,3,4-oxadiazole, 2-trichloromethyl-5-furyl-1,3,4-oxadiazole and the like.

The biimidazole compound is not particularly limited. For example, biimidazole compounds include 2,2'-bis (2-chlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis. (2,4-dichlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4' , 5,5'-Tetraphenyl-1,2'-biimidazole and the like.

The oxime ester compound is not particularly limited. For example, the oxime ester compounds are 1- [4- (phenylthio)-, 2- (O-benzoyloxime)] -1,2-octanedione, 1- [9-ethyl-6- (2-). Methylbenzoyl) -9H-carbazole-3-yl]-, 1- (O-acetyloxime) esterone and the like.

The titanocene compound is not particularly limited. For example, the titanocene compound is bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium or the like. is there.

The benzoic acid ester compound is not particularly limited. As an example, the benzoic acid ester compound is p-dimethylaminobenzoic acid, p-diethylaminobenzoic acid and the like.

The acridine compound is not particularly limited. As an example, the acridine compound is 9-phenylacridine or the like.

The content of the photopolymerization initiator is not particularly limited. As an example, the content of the photopolymerization initiator in the ink is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. The content of the photopolymerization initiator in the ink is preferably 15% by mass or less, and more preferably 12% by mass or less. When the content of the photopolymerization initiator is within the above range, the ink is likely to be appropriately cured by ultraviolet rays.

(Organic solvent)
The organic solvent is a liquid component for dissolving an ultraviolet curable oligomer in an ink. The type of organic solvent is not particularly limited. For example, the organic solvent is a glycol ether solvent, an acetate solvent, an alcohol solvent, a ketone solvent, an ester solvent, a hydrocarbon solvent, a fatty acid ester solvent, an aromatic solvent and the like. The organic solvent may be used in combination. Among these, the organic solvent of the present embodiment preferably contains at least one of a glycol ether solvent and an acetate solvent. Both the glycol ether solvent and the acetate solvent have a low viscosity and a relatively high boiling point. Therefore, the ink containing these as a solvent has more improved drying property and more excellent ejection stability at the time of inkjet printing. Further, in consideration of less adverse effect on the inkjet print head, good ink adhesion due to moderate erosion on the substrate, compatibility with ultraviolet curable oligomers, and stability when the pigment is dispersed in the ink described later. The ink more preferably contains a glycol ether solvent.

Glycol ether-based solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono (iso) propyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, and propylene glycol. Monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n -Butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono-n-propyl ether, triethylene glycol mono-n-butyl ether, tripropylene glycol monoethyl ether, tripropylene glycol mono-n-propyl Ether, tripropylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether , Triethylene glycol butyl methyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether and the like are exemplified.

Acetate-based solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol mono-sec-butyl ether acetate, Ethylene glycol monoisobutyl ether acetate, ethylene glycol mono-tert-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monoisopropyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol mono-n-butyl ether Acetate, Propylene Glycol Mono-sec-Butyl Ether Acetate, Propylene Glycol Monoisobutyl Ether Acetate, Propylene Glycol Mono-tert-Butyl Ether Acetate, 3-Methyl-3-methoxybutyl Acetate, 3-Methyl-3-ethoxybutyl Acetate, 3-Methyl -3-Propoxybutyl Acetate, 3-Methyl-3-Isopropoxybutyl Acetate, 3-Methyl-3-n-Butoxyethyl Acetate, 3-Methyl-3-isobutoxycybutyl Acetate, 3-Methyl-3-sec- Butoxysibutyl acetate, alkylene glycol monoalkyl ether acetates such as 3-methyl-3-tert-butoxysibutyl acetate, ethylene glycol diacetate, diethylene glycol diacetate, triethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol Examples thereof include diacetate and tripropylene glycol diacetate.

The organic solvent of the present embodiment preferably has a boiling point of 150 ° C. or higher, more preferably 160 ° C. or higher. The organic solvent has a boiling point of 250 ° C. or lower, more preferably 220 ° C. or lower. When the boiling point is within the above range, the ink does not easily dry the inkjet nozzle of the inkjet recording device, and the ejection stability is excellent. In addition, the organic solvent of the ink is easily removed by drying, and a delicate and clear printed matter with less bleeding is easily formed.

The content of the organic solvent is not particularly limited. As an example, the amount of the organic solvent in the ink is preferably 50% by mass or more, and more preferably 60% by mass or more. The organic solvent is preferably 80% by mass or less, and more preferably 70% by mass or less in the ink. When the content of the organic solvent is less than 50% by mass, the viscosity of the ink tends to be high, and the ejection stability during inkjet printing tends to decrease. On the other hand, when the content of the solvent exceeds 80% by mass, the proportion of the ultraviolet curable oligomer that can be added to the ink becomes low, and it tends to be difficult to obtain the desired performance.

The ink of the present embodiment may contain water in addition to the organic solvent. When water is contained, the content of water in the ink is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less. Also, water does not have to be contained.

(Optional ingredient)
In addition to the above-mentioned UV-curable oligomer, photopolymerization initiator and organic solvent, the ink of the present embodiment may contain arbitrary components well known in the field of ink. As an example, optional components include ultraviolet curable monomers, color pigments, curing catalysts, light stabilizers, slip agents (leveling agents), dispersants, polymerization accelerators, polymerization inhibitors, penetration accelerators, and wetting agents (moisturizing agents). Agent), fixing agent, fungicide, preservative, antioxidant, chelating agent, thickener, etc.

-Ultraviolet-curable monomer The ultraviolet-curable monomer is suitably contained in order to maintain an appropriate viscosity without increasing the viscosity of the ink too much and to increase the solid content of the ink. Due to the inclusion of the ultraviolet curable monomer, the ink is more likely to be thickly expressed.

The ultraviolet curable monomer is not particularly limited. As an example, the ultraviolet curable monomer is a (meth) acrylamide-based, (meth) acrylate-based monofunctional or polyfunctional ultraviolet curable monomer and the like.

Monofunctional UV curable monomers include (meth) acrylic acid, itaconic acid, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-ethylaminoethyl (meth) acrylamide, diacetone (meth) acrylamide, N-vinylpyrrolidone, N- (meth) acryloylpyrrolidone, 2-hydroxyethyl ( Examples thereof include meta) acrylate, 2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, glycerol (meth) acrylate, and (methoxy) polyethylene glycol (meth) acrylate.

The bifunctional UV curable monomer is triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexane. Diol diacrylate, 1,9-nonane diol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, EO (ethylene oxide) adduct diacrylate of bisphenol A, PO (propylene oxide) adduct diacrylate of bisphenol A Acrylate, neopentyl glycol diacrylate hydroxypivalate, polytetramethylene glycol diacrylate and the like.

The trifunctional UV curable monomer is a triacrylate or trimethacrylate of a trihydric or higher polyhydric alcohol such as trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, or pentaerythritol trimethacrylate.

The tetrafunctional or higher ultraviolet curable monomers are tricyclodecandi (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1, 6-Hexanediol di (meth) acrylate, trimethylol propanetri (meth) acrylate, trimethylol propane polyethoxytri (meth) acrylate, trimethylol propane polypropoxytri (meth) acrylate, glycerin polypropoxytri (meth) acrylate, Bisphenol A polyethoxydi (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, dipentaerythritol penta and hexa (meth) acrylate mixture, dipentaerythritol polyethoxy Hexa (meth) acrylate, dipentaerythritol polypropoxyhexa (meth) acrylate and the like.

Among these, the ultraviolet curable monomer is preferably a monofunctional or bifunctional ultraviolet curable monomer, and more preferably a monofunctional ultraviolet curable monomer, from the viewpoint that a flexible coating film can be easily obtained.

When the ultraviolet curable monomer is contained, the content of the ultraviolet curable monomer is not particularly limited. As an example, the content of the ultraviolet curable monomer is preferably 1% by mass or more, and more preferably 5% by mass or more in the ink. The content of the ultraviolet curable monomer is preferably 12% by mass or less, and more preferably 10% by mass or less in the ink. When the content of the ultraviolet curable monomer is within the above range, the rate of increase in viscosity of the ink can be easily adjusted by being applied to the substrate and then dried. As a result, the ink is more likely to perform delicate image expression and thick expression.

When the ultraviolet curable monomer is contained, the content of the ultraviolet curable monomer is preferably 0.4 times or less, preferably 0.3 times or less, the content of the ultraviolet curable oligomer in terms of mass ratio. More preferably. When the content ratio of the ultraviolet curable monomer to the ultraviolet curable oligomer is within the above range, the rate at which the viscosity of the ink increases is easily adjusted by being applied to the substrate and then dried. As a result, the ink is more likely to perform delicate image expression and thick expression.

-Coloring pigments Coloring pigments are suitably contained in order to impart a desired color to an inkjet image layer. The coloring pigment may contain various inorganic pigments or organic pigments. Inorganic pigments include oxides, composite oxides, hydroxides, sulfides, ferrocyanides, chromates, carbonates, silicates, phosphates, carbons (carbon black), and metals. Examples include powders and the like. Organic pigments include nitroso, dyed lakes, azolakes, insoluble azos, monoazos, disazos, condensed azos, benzoimidazolones, phthalocyanines, anthraquinones, perylenes, quinacridones, dioxazines, iso. Examples thereof include indolines, azomethines, pyrrolopyrroles and the like. Color pigments may be used in combination.

As the coloring pigment of the present embodiment, it is preferable to use an organic pigment from the viewpoint of excellent color development of the obtained printed matter. Further, as the coloring pigment, an inorganic pigment may be used when the weather resistance of the obtained printed matter is further improved.

Further, the coloring pigment may be dispersed in various dispersants. The coloring pigment of the present embodiment is more preferably a coloring pigment dispersed by a polymer dispersant from the viewpoint that the water repellency of the obtained printed matter is more excellent.

The polymer dispersant is not particularly limited. For example, the polymer dispersant is a polyoxyalkylene polyalkylene polyamine, a vinyl polymer or copolymer, an acrylic polymer or copolymer, a polyester, a polyamide, a polyimide, a polyurethane, an amino polymer, or the like. The polymer dispersant may be used in combination.

The acid value of the polymer dispersant is preferably 5 mgKOH / g or more, and more preferably 15 mgKOH / g or more. The amine value of the polymer dispersant is preferably 15 mgKOH / g or more, and more preferably 25 mgKOH / g or more. The polymer dispersants having these acid values and amine values have excellent adsorptivity to coloring pigments. In the present embodiment, the acid value represents the acid value per 1 g of the solid content of the dispersant, and can be calculated by the potentiometric titration method according to JIS K 0070. The amine value represents the amine value per 1 g of solid dispersant, and is calculated by converting the value calculated by the potentiometric titration method using a 0.1 mol / L hydrochloric acid aqueous solution into the equivalent of potassium hydroxide. Can be.

When the coloring pigment is contained, the content of the coloring pigment is preferably 0.01% by mass or more, and preferably 0.1% by mass or more in the ink. Further, the content of the coloring pigment is preferably 5% by mass or less, and more preferably 2% by mass or less in the ink. When the content of the coloring pigment is within the above range, the ink can easily sufficiently color the obtained printed matter without inferior in ejection stability.

-Curing catalyst The curing catalyst is not particularly limited. For example, the curing catalyst is an organic acid salt of a metal such as tin, titanium, zirconium, iron, antimony, bismuth, manganese, zinc, aluminum; an alcoholate and a chelating compound; an amine such as hexylamine, dodecylamine; an acetate. Amine salts such as hexylamine and dodecylamine phosphate; quaternary ammonium salts such as benzyltrimethylammonium acetate; alkali metal salts such as potassium acetate and the like. More specifically, the curing catalyst is an organic bismuth compound such as bismuth octylate or bismuth neodecanoate, an organic tin compound such as dibutyltin dilaurate, dibutyltin dioctylate, dimethyltin dineodecanate, or stanus octoate, tetrabutyl titanate, or tetra. Organic titanium compounds such as isopropyl titanate, diisopropoxybis (acetylacetone) titanium, and diisopropoxybis (ethylacetacetate) titanium. The curing catalyst may be used in combination.

When the curing catalyst is contained, the content of the curing catalyst is not particularly limited. As an example, the content of the curing catalyst in the ink is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. The content of the curing catalyst in the ink is preferably 2% by mass or less, and more preferably 1% by mass or less. When the content of the curing catalyst is within the above range, the ink has excellent ejection stability and tends to exhibit appropriate curability.

-Light stabilizer The light stabilizer is not particularly limited. As an example, the light stabilizers are bis (2,2,6,6-tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis ( 2,2,6,6-tetramethyl-4-piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidin, 4-octanoyloxy-2,2,6,6-tetramethyl Piperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) diphenylmethane-p, p'-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) benzene-1, Hindered amines such as 3-disulfonate, bis (2,2,6,6-tetramethyl-4-piperidyl) phenylphosphite, nickel bis (octylphenyl sulfide, nickel complex-3,5-di-t-butyl- A nickel complex such as 4-hydroxybenzyl phosphate monoethylate or nickel dibutyldithiocarbamate. A light stabilizer may be used in combination.

When a light stabilizer is contained, the content of the light stabilizer is not particularly limited. As an example, the content of the light stabilizer is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more in the ink. The content of the light stabilizer is preferably 2% by mass or less, and more preferably 1% by mass or less in the ink. When the content of the light stabilizer is within the above range, the ink can easily obtain a printed matter having excellent light resistance.

-Polymerization inhibitor The polymerization inhibitor is suitably contained in order to prevent the polymerization reaction of the ink before curing. The polymerization inhibitor is not particularly limited. For example, the polymerization inhibitors are methylhydroquinone, t-butylhydroquinone, 4-methoxynaphthol, 1,4-benzoquinone, methquinone, dibutylhydroxytoluene, N-nitrosophenylhydrocyclamine aluminum salt, 1,4-naphthoquinone. , 4-Hydroxy-2,2,6,6-tetramethylpiperidin1-oxyl (4-hydroxyTEMPO) and the like. The polymerization inhibitor may be used in combination.

When a polymerization inhibitor is contained, the content of the polymerization inhibitor is not particularly limited. As an example, the content of the polymerization inhibitor is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more in the ink. The content of the polymerization inhibitor is preferably 2% by mass or less, and more preferably 1% by mass or less in the ink. When the content of the polymerization inhibitor is within the above range, the ink is likely to prevent the polymerization reaction before curing.

Returning to the description of the entire ink, the ink of the present embodiment may have a viscosity of 5 mPa · s or more at 50 ° C., preferably 7 mPa · s or more. The viscosity of the ink at 50 ° C. may be 20 mPa · s or less, preferably 15 mPa · s or less. When the viscosity of the ink at 50 ° C. is less than 5 mPa · s, the amount of the solvent contained in the ink is large, and it tends to be difficult to obtain the desired thickening expression. Further, when the viscosity of the ink at 50 ° C. exceeds 20 mPa · s, the ejection stability of the ink tends to decrease. In this embodiment, the viscosity can be measured using a B-type viscometer (TVB-20LT, manufactured by Toki Sangyo Co., Ltd.).

The method of adjusting the viscosity within the above range is not particularly limited. As an example, the viscosity can be adjusted by the amount and type of each component used. The viscosity may be adjusted by using a viscosity modifier such as a thickener, if necessary.

The surface tension of the ink is not particularly limited. The surface tension of the ink is preferably 20 dyne / cm or more, and more preferably 25 dyne / cm or more at 25 ° C. The surface tension of the ink is preferably 40 dyne / cm or less, and more preferably 35 dyne / cm or less at 25 ° C. When the surface tension is within the above range, the ink has excellent ejection stability. In addition, the ink is less likely to be repelled and bleeding on the substrate. In this embodiment, the surface tension can be measured using a static surface tension meter (plate method) (CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd.).

The method of adjusting the surface tension within the above range is not particularly limited. As an example, the surface tension can be adjusted by adding an acrylic surface conditioner, a silicone surface conditioner, a fluorine surface conditioner, or the like.

As described above, the ink of the present embodiment contains an ultraviolet curable oligomer having a viscosity at 60 ° C. of 20,000 mPa · s or more. When such an ink is applied to a base material and then dried, the viscosity of the ink rapidly increases, and it becomes difficult for the ink to wet and spread on the base material. As a result, the ink is easy to perform delicate image expression and thick expression. In addition, the UV-curable oligomer has a smaller number of cross-linking points during curing than the UV-curable monomer. Therefore, the obtained inkjet image layer is flexible, can follow large deformation of the base material, and is less likely to crack.

<Manufacturing method of printed matter and printed matter>
The method for producing a printed matter according to an embodiment of the present invention includes an inkjet step of forming an image on a substrate by an inkjet method using the above ink, a volatilization step of volatilizing an organic solvent, and irradiation with ultraviolet rays. It includes a curing step of curing the ink. As another process, a process generally used in manufacturing a conventional printed matter may be adopted. The obtained printed matter includes a base material and an inkjet image layer formed on the base material by the above-mentioned ink.

(Inkjet process)
The inkjet step is a step of forming an image on a substrate by an inkjet method using the above-mentioned ink. The method of applying ink to the substrate by the inkjet recording method is not particularly limited. Examples of such a method include a continuous method such as a charge modulation method, a microdot method, a charge injection control method, and an ink mist method, a piezo method, a pulse jet method, a bubble jet (registered trademark) method, and an electrostatic suction method. -The demand method and the like are exemplified.

The base material is not particularly limited. For example, the base material is various woven fabrics, knitted fabrics, non-woven fabrics, natural leather, synthetic leather, artificial leather, vinyl chloride leather, steel plate, aluminum, metal plate such as stainless steel, acrylic, polycarbonate, ABS, polypropylene, polyester. , Polyvinyl chloride (PVC) and other plastic plates or films, ceramic plates, concrete, wood, glass and the like. The fibers that make up the fabric are not particularly limited. As an example, the fibers are natural fibers, regenerated fibers, semi-synthetic fibers, synthetic fibers and the like. Synthetic fibers are polyester-based such as cationic dyeable polyester (CDP) fiber, polyethylene terephthalate (PET) fiber, polybutylene terephthalate (PBT) fiber, polytrimethylene terephthalate (PTT) fiber, total aromatic polyester fiber, and polylactic acid fiber. Fibers, acetate fibers, triacetate fibers, polyurethane fibers, nylon fibers and the like, or composite fibers thereof and the like.

As described above, the ink of the present embodiment exhibits excellent followability even when the base material is significantly deformed and processed after being applied to the base material. Therefore, the base material may be a base material used for such a greatly deformed application.

The amount of ink applied is not particularly limited. As an example, the ink application amount is preferably at 1 g / m ² or more to the substrate, and more preferably 10 g / m ² or more. The amount of ink applied is preferably 100 g / m ² or less, and more preferably 80 g / m ² or less. When the amount of ink applied is within the above range, the printed matter can be expressed in thick layers, and a delicate image can be expressed.

(Volatilization process)
The volatilization step is a step of volatilizing the organic solvent in the ink, and heat-treats the base material to which the ink is applied. When the organic solvent is volatilized by the heat treatment, the viscosity of the ink rapidly increases, and it becomes difficult for the ink to wet and spread on the substrate. As a result, the ink is easy to perform delicate image expression and thick expression.

The heat treatment conditions are not particularly limited. As an example, the heat treatment temperature is preferably 50 ° C. or higher, more preferably 55 ° C. or higher. The heat treatment temperature is preferably 80 ° C. or lower, more preferably 70 ° C. or lower. When the heat treatment temperature is within the above range, the ink can easily perform delicate image expression and thick image expression.

The heat treatment time is not particularly limited. As an example, the heat treatment time is preferably 0.5 minutes or more, and more preferably 1 minute or more. When the heat treatment time is within the above range, the ink can easily perform delicate image expression and thick image expression. The upper limit of the heat treatment time is not particularly limited. The upper limit of the heat treatment time is appropriately set in consideration of the productivity of the printed matter. As an example, the heat treatment time is preferably 60 minutes or less, and more preferably 30 minutes or less.

Since the above-mentioned ink is used in the method for producing a printed matter of the present embodiment, an inkjet image layer having a sufficient height can be formed by one inkjet step and a volatilization step, which is an excellent thickening expression. It can be performed. However, in the method for producing a printed matter of the present embodiment, a curing step described later may be performed after the volatilization step, and if necessary, in order to perform a thicker expression with a larger height, the inkjet step is performed again. The volatilization step may be repeated.

(Curing process)
The curing step is a step of irradiating ultraviolet rays to cure the ink. According to the curing step, the viscosity is increased by the volatilization step and the three-dimensionally applied ink is cured to form an inkjet image layer.

The curing conditions of the ink are not particularly limited. As an example, the ultraviolet irradiation intensity is preferably 50 mW / cm ² or more, and more preferably 100 mW / cm ² or more. The ultraviolet irradiation intensity is preferably at 2000 mW / cm ² or less, more preferably 1500 mW / cm ² or less. When the ultraviolet irradiation intensity is within the above range, the obtained printed matter is easily cured appropriately and is less likely to cause yellowing or the like.

The ultraviolet irradiation energy (integrated light intensity) is not particularly limited. As an example, the integrated light intensity is preferably 50 mJ / cm ² or more, and more preferably 100 mJ / cm ² or more. Further, the integrated light quantity is preferably at 2000 mJ / cm ² or less, more preferably 1500 mJ / cm ² or less. When the integrated light intensity is within the above range, the obtained printed matter is easily cured appropriately and is less likely to cause yellowing or the like.

According to the method for producing a printed matter of the present embodiment, a printed matter in which an inkjet image layer is formed on a substrate is obtained by the above-mentioned inkjet step, volatilization step, and curing step. The obtained printed matter can be subjected to delicate image expression and thick expression. Further, the inkjet image layer formed on the printed matter is flexible, can follow a large deformation of the base material, and is less likely to be cracked.

For example, in the printed matter of the present embodiment, the ink (injection image layer) applied to the base material can sufficiently follow even when it is stretched by 30% or more. Therefore, the printed matter may be appropriately shaped, stretched, and processed into a molded product. The printed matter of the present embodiment may be used not only for the purpose of being molded and stretched after being applied to the base material, but also for the purpose of stretching the base material itself.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to these examples.

The raw materials used are shown below.
<Organic solvent>
Organic solvent 1: DEDG, diethylene glycol diethyl ether, glycol ether-based organic solvent, manufactured by Nippon Emulsifier Co., Ltd., boiling point: 188 ° C.
Organic solvent 2: High solve MDM, dimethylene glycol dimethyl ether, glycol ether-based organic solvent, manufactured by Toho Kagaku Kogyo Co., Ltd., boiling point: 162 ° C.
Organic solvent 3: High solve MTPOM, tripropylene glycol dimethyl ether, glycol ether-based organic solvent, manufactured by Toho Chemical Industry Co., Ltd., boiling point: 215 ° C.
<UV curable oligomer>
UV curable oligomer 1: Polycarbonate urethane acrylate oligomer, viscosity at 60 ° C: 38000 mPa · s, ART RESIN UN-9511, manufactured by Negami Kogyo Co., Ltd. UV curable oligomer 2: aliphatic urethane acrylate oligomer, viscosity at 60 ° C: 25000 mPa · s, CN8888, UV curable oligomer manufactured by Alchema Co., Ltd .3: Polycarbonate urethane acrylate oligomer, viscosity at 60 ° C .: 210000 mPa · s, ART RESIN UN-9512, UV curable oligomer manufactured by Negami Kogyo Co., Ltd. 4: Aromatic urethane acrylate oligomer, viscosity at 60 ° C: 15000 mPa · s, CN9783, manufactured by Alchema Co., Ltd. UV curable oligomer 5: Urethane acrylate oligomer, viscosity at 60 ° C, 17675 mPa · s, CN964, manufactured by Alchema Co., Ltd. <UV Curable Oligomer>
UV-curable monomer 1: 2-methyl acrylate (acrylate-based monofunctional UV-curable monomer), FX-AO-MA, manufactured by Nippon Catalyst Co., Ltd. <Photopolymerization initiator>
Photopolymerization Initiator 1: α-Hydroxyacetophenone-based Polymerization Initiator, Omnirad 184, IGM Resins B.I. V. Photopolymerization Initiator 2: Acylphosphine Oxide-based Polymerization Initiator, Omnirad 819, IGM Resins B.I. V. <Colored pigment>
Coloring Pigment 1: Azonickel Yellow Pigment, CROMOPHTAL YELLOW D1085, BASF Colored Pigment 2: Quinacridone Red Pigment, Ink Jet Red E5B 02, Clariant Japan Co., Ltd. Colored Pigment 3: Copper Phthalocyanin Blue Pigment, Hostaperm Blue 217D , Clariant Japan Co., Ltd. Color pigment 4: Carbon-based (carbon black) black pigment, NIPEX35, Orion Engineered Carbons Co., Ltd. <Polymer prohibition agent>
Polymerization inhibitor 1: Hindered amine-based polymerization inhibitor, Bis (2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl) sebacate, manufactured by Shanghai Satsuma Biochemical Technology Co., Ltd.

<Ink preparation>
The method of preparing the ink is shown below.
Each pigment was dispersed with the following formulation to prepare a masterbatch.
(K masterbatch)
Pigment (colored pigment 4) 15 parts by mass Dispersant SOLSPERSE 33000 (manufactured by Lubrizol) 4.5 parts by mass Solvent DEDG (diethylene glycol diethyl ether, manufactured by Nippon Emulsifier Co., Ltd.) 80.5 parts by mass (Y masterbatch)
Pigment (colored pigment 1) 15 parts by mass Dispersant SOLSPERSE 32000 (manufactured by Lubrizol) 3.75 parts by mass Solvent DEDG (diethylene glycol diethyl ether, manufactured by Nippon Emulsifier Co., Ltd.) 81.25 parts by mass (M masterbatch)
Pigment (colored pigment 2) 15 parts by mass Dispersant SOLSPERSE 32000 (manufactured by Lubrizol) 3.75 parts by mass Solvent DEDG (diethylene glycol diethyl ether, manufactured by Nippon Emulsifier Co., Ltd.) 81.25 parts by mass (C masterbatch)
Pigment (colored pigment 3) 15 parts by mass Dispersant SOLSPERSE 32000 (manufactured by Lubrizol) 3.75 parts by mass Solvent DEDG (diethylene glycol diethyl ether, manufactured by Nippon Emulsifier Co., Ltd.) 81.25 parts by mass

(Example 1)
30.0 parts by mass of UV curable oligomer 1 dissolved in 68.0 parts by mass of organic solvent 1 (DEDG), 2.0 parts by mass of photopolymerization initiator 1, 0.05 parts by mass of polymerization inhibitor A clear ink was prepared by mixing and dissolving 1 and then filtering. Using the obtained ink, an inkjet print is performed on the base material (synthetic leather) under the following inkjet conditions (injection step), and then the solvent is volatilized under the following volatilization step conditions (volatile step). , The ink was cured under the following conditions of the curing step (curing step) to prepare a printed matter.

(Inkjet process)
The ink was applied under the following ink conditions so that the amount of resin (oligomer and monomer) applied to each ink was 67.5 g / m ² .
<Inkjet conditions>
(Inkjet process)
Inkjet recording device: Piezo method Nozzle diameter: 40 μm
Drive voltage: 100V
Frequency: 8kHz
Resolution: 400 x 400 dpi
Base material temperature: 60 ° C (warming)
(Volatilization process)
After the inkjet process was completed, the state of being heated to 60 ° C. was maintained for 5 minutes to volatilize the organic solvent.
(Curing process)
After the volatilization step, curing was performed using a metal halide lamp at an illuminance of 680 mW / cm ² and an integrated light intensity of 750 mJ / cm ² .

(Examples 2 to 12, Comparative Examples 1 to 2)
A printed matter was produced by performing inkjet printing in the same manner as in Example 1 except that the types and formulations of the raw materials used were changed as shown in Table 1.

Viscosity (50 ° C.), three-dimensional effect, sharpness, presence / absence of cracks, durability test for inks and printed matter obtained in Examples 1 to 12 and Comparative Examples 1 and 2 based on the following evaluation methods and evaluation criteria. , The height of the heap (μm) was evaluated. The results are shown in Table 1.

<Viscosity (50 ° C)>
The ink was adjusted to 50 ° C., and the viscosity (mPa · s) was measured using a B-type viscometer (TVB-20LT manufactured by Toki Sangyo Co., Ltd.).

<Three-dimensional effect>
The three-dimensional effect of the printed matter was evaluated by touching the finger.
(Evaluation criteria)
◯: Unevenness due to touch was strongly felt at the boundary portion with and without the printed pattern.
Δ: Some unevenness due to touch was felt at the boundary portion with and without the printed pattern.
X: No unevenness due to touch was felt at the boundary portion with and without the printed pattern.

<Clarity>
The sharpness of the printed matter was visually evaluated.
(Evaluation criteria)
◯: The edge of the printed pattern was clear, and there was no bleeding or spreading.
Δ: Some bleeding or spreading occurred at the edge of the printed pattern.
X: Large bleeding and spreading occurred at the edge of the printed pattern.

<Presence or absence of cracks>
The printed matter was stretched by 30% while being heated to 150 ° C., and the presence or absence of cracks in the ink layer was visually evaluated.
(Evaluation criteria)
◯: No abnormality occurred in the ink layer.
Δ: The ink layer was cracked, but no rupture occurred.
X: The ink layer was torn and the surface of the base material was exposed from the gap.

<Durability test>
The durability was evaluated by performing a Scott kneading test on the printed matter under a load of 1 kg and measuring the number of times until the ink film was damaged.
(Evaluation criteria)
◯: No cracking occurred after 10,000 times of Scott kneading.
Δ: Cracks occurred up to 10,000 times of Scott kneading.
X: Cracks occurred up to 5,000 times when Scott was rubbed.

<Height of excitement>
The height (μm) of the printed matter was evaluated by observing a cross-sectional image of the ink layer with an SEM (scanning electron microscope) and measuring the thickness.
(Evaluation criteria)
◯: The thickness of the ink layer was 65 μm or more.
Δ: The thickness of the ink layer was 30 μm or more and less than 65 μm.
X: The thickness of the ink layer was less than 30 μm.

As shown in Table 1, the inkjet inks and printed matter of Examples 1 to 12 of the present invention have a delicate image representation by using an oligomer having a viscosity of 20,000 mPa · s or more at 60 ° C. It was possible to express a thick plate with a large height, and the ink film had sufficient durability. It is presumed that this is because the ink liquid rapidly thickened in the solvent volatilization process, and the ink stayed in place without getting wet and spreading. On the other hand, the inkjet ink and printed matter of Comparative Example 1 were inferior in three-dimensionality and sharpness, and inferior in durability performance of the ink film, due to the use of an oligomer having a viscosity of less than 20,000 mPa · s at 60 ° C. ..

Claims (8)

An inkjet ink containing an ultraviolet curable oligomer, a photopolymerization initiator, and an organic solvent.
The viscosity of the inkjet ink at 50 ° C. is 5 to 20 mPa · s.
An inkjet ink having a viscosity of the ultraviolet curable oligomer at 60 ° C. of 20,000 mPa · s or more. The inkjet ink according to claim 1, wherein the content of the ultraviolet curable oligomer is 20 to 50% by mass in the inkjet ink. The inkjet ink according to claim 1 or 2, further comprising an ultraviolet curable monomer. The inkjet ink according to claim 3, wherein the content of the ultraviolet curable monomer is 0.4 times or less the content of the ultraviolet curable oligomer in terms of mass ratio. The inkjet ink according to any one of claims 1 to 4, wherein the organic solvent has a boiling point of 150 to 250 ° C. In addition, it contains coloring pigments,
The inkjet ink according to any one of claims 1 to 5, wherein the content of the coloring pigment is 5% by mass or less in the inkjet ink. A printed matter comprising a base material and an inkjet image layer formed on the base material by the inkjet ink according to any one of claims 1 to 6. An inkjet step of forming an image on a substrate by an inkjet method using the inkjet ink according to any one of claims 1 to 6.
The volatilization step of volatilizing the organic solvent and
A method for producing a printed matter, which includes a curing step of irradiating ultraviolet rays to cure the ink for an inkjet.