JP2011207994A - Ink set for inkjet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-curable ink set for inkjet recording that forms an image in which color bleed is suppressed without being restrained by printing speed.SOLUTION: In the ink set for inkjet recording, which includes an ultraviolet-curable black ink composition and at least one or more ultraviolet-curable color ink compositions, each ink composition contains a pigment, a polymerizable monomer, and a photopolymerization initiator. The modal particle size of the pigment contained in the ultraviolet-curable black ink composition is 80-250 nm, and the modal particle size of the pigment contained in at least any one of ultraviolet-curable color ink compositions is not less than 10 nm and less than 80 nm.

Description

  The present invention relates to an ink set for ink jet recording comprising a black ink composition and a color ink composition that are cured by ultraviolet rays, and more particularly, a non-ink-absorbing material such as plastic or metal or an ink-absorbing material. The present invention relates to an ink set for ink jet recording provided with an ink composition suitable for recording on a low material (that is, a non-ink-absorbing material). More specifically, the present invention relates to an ink set for ink jet recording capable of forming an image in which so-called color bleeding is suppressed, which causes color turbidity when ink liquids having different hues are mixed on a recording medium.

The ink jet recording method is a printing method in which printing is performed by causing a droplet of an ink composition to fly and adhere to a recording medium such as paper. This ink jet recording method is characterized in that a high-resolution and high-quality image can be printed at high speed. The ink composition used in the ink jet recording method generally contains an aqueous solvent as a main component and contains a coloring component and a wetting agent such as glycerin for the purpose of preventing clogging.
On the other hand, paper or fabrics that are difficult to penetrate water-based ink compositions, or materials such as metals, plastics, and the like that do not penetrate, such as phenol, melamine, vinyl chloride, acrylic, polycarbonate, PET, PP, and PE When printing on a recording medium such as a film, the ink composition is required to contain a component capable of stably fixing the coloring material to the recording medium.

  In response to these requirements, conventionally, an ink composition containing a component that is polymerized by ultraviolet irradiation has been proposed (see, for example, Patent Document 1). In addition, an ultraviolet curable ink composition containing a coloring material, an ultraviolet curing agent, a photopolymerization initiator, and the like has been proposed (see, for example, Patent Document 2). As described above, in an ink jet recording method using an ink composition containing a component that is polymerized by irradiation with light such as ultraviolet rays, the ink composition is attached to a recording medium, and then ultraviolet rays are applied. Etc. Light is irradiated. Then, the photopolymerization initiator in the ink composition generates radicals and the like, whereby the oligomer and the monomer start to be polymerized and harden, so that the color material in the ink composition is fixed on the recording medium. However, these methods have a problem in that ink does not cure on the recording medium in time, and ink liquids having different hues are mixed with each other to cause color turbidity (color bleeding).

  Therefore, in Patent Documents 3 to 5, the structure of the ink jet recording apparatus is improved, and the curing rate of the ink of each hue is accelerated by controlling the irradiation condition of light such as ultraviolet rays and the ejection amount of the ink. Methods of suppressing have been proposed. Patent Document 6 proposes an ink composition in which the occurrence of color bleeding is suppressed by containing photoreactive polymer fine particles.

JP-A-3-216379 US Pat. No. 5,562,001 JP 2007-136988 A JP 2007-144737 A JP 2010-691 A JP 2001-115067 A

  However, the methods of Patent Documents 3 to 5 have a drawback in that the printing speed and the image quality after printing are limited because the irradiation conditions of light such as ultraviolet rays and the ink discharge amount are limited. Further, in the ink composition of Patent Document 6, there is a concern about the influence of the photoreactive polymer fine particles on the ejection reliability of the ink during printing.

  The present invention has been made paying attention to the above-mentioned problems in conventional ink sets for inkjet recording, and the object thereof is to form an image with suppressed color bleeding without being limited by the printing speed. Another object of the present invention is to provide an ink set for ultraviolet curable ink jet recording.

  As a result of intensive studies to achieve the above object, the present inventors have determined that the particle size distribution of the black pigment contained in the black ink composition constituting the ink set for ink jet recording is set to the large particle size side, and the color ink composition The inventors have found that the above object can be achieved by shifting the particle size distribution of the color pigment contained in the product to the small particle size side, and have completed the present invention.

That is, the present invention is as follows.
(1) An ink set for inkjet recording comprising an ultraviolet curable black ink composition and at least one ultraviolet curable color ink composition,
Each ink composition contains a pigment, a polymerizable monomer and a photopolymerization initiator,
The mode diameter of the pigment contained in the ultraviolet curable black ink composition is 80 nm or more and 250 nm or less,
An ink set for inkjet recording, wherein a mode particle diameter of a pigment contained in at least one of the ultraviolet curable color ink compositions is 10 nm or more and less than 80 nm.
(2) The ultraviolet curable ink set for inkjet recording according to (1), wherein the ultraviolet curable black ink composition further contains a resin having a weight average molecular weight of 4,000 to 50,000.
(3) The ink jet recording apparatus according to (1) or (2), wherein the polymerizable monomer is a radical polymerizable monomer, and the photopolymerization initiator is a photo radical generator. Ink set.
(4) For inkjet recording according to (1) or (2), wherein the polymerizable monomer is a cationic polymerizable monomer, and the photopolymerization initiator is a photoacid generator. Ink set.

  According to the present invention, the particle size distribution of the black pigment contained in the black ink composition constituting the ink set is shifted to the large particle size side, and the particle size distribution of the color pigment contained in the color ink composition is shifted to the small particle size side. Therefore, it is possible to provide an ultraviolet curable ink set for inkjet recording that can form an image with suppressed color bleeding without being limited by the printing speed.

It is a figure which shows the evaluation pattern of the printed matter for evaluation in an Example.

Hereinafter, the ink set for ink jet recording of the present invention (hereinafter also referred to as “ink set”) will be described in detail.
The present invention is an ink jet recording ink set comprising an ultraviolet curable black ink composition and at least one ultraviolet curable color ink composition, each ink composition comprising a pigment, a polymerizable monomer And the mode diameter of the pigment contained in the ultraviolet curable black ink composition is from 80 nm to 250 nm, and at least one of the ultraviolet curable color ink compositions An ink set for inkjet recording, wherein the mode particle size of the pigment contained is 10 nm or more and less than 80 nm.

Here, the ultraviolet curable black ink composition (hereinafter, also referred to as “black ink composition”) is a black, gray or light black hue, more preferably a basic color black, which is irradiated with ultraviolet rays. An ink composition that undergoes a curing reaction.
On the other hand, an ultraviolet curable color ink composition (hereinafter also referred to as “color ink composition”) has a hue of yellow, magenta, cyan, light magenta, red, light cyan or blue, and is cured by irradiation with ultraviolet rays. There are ink compositions in which a reaction occurs, and types of color ink compositions include yellow ink compositions, magenta ink compositions, and cyan ink compositions corresponding to hues. Among these, an ink composition having a light-colored hue that easily causes color turbidity when mixed with black, that is, a yellow ink composition, a light magenta ink composition, and a light cyan ink composition having a large difference in brightness from black, particularly In the yellow ink composition, the effect of suppressing color bleeding is remarkable.
Of the above hues, yellow, magenta, cyan, and black are basically four colors, light magenta is magenta light, red is magenta dark, light cyan is cyan light, blue is cyan dark, gray, and so on. Light black is a light color of black.

As the pigment used in the present invention, inorganic pigments and organic pigments can be used without any particular limitation.
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, quinacridone pigments, dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

  Specific examples of pigments that can be used in the black ink composition include carbon black, No. manufactured by Mitsubishi Chemical Corporation. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B, etc. are Raven 5750, 5250, 5000, 3500, 1255, 700, etc. made by Columbia, and Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, made by Cabot, 900, 1000, 1100, 1300, 1400, etc. are Degussa Color Black FW1, FW2, FW2V, FW18, FW200, ColorBlack S150, S160, S170, Printex 35, U, the same V, the same 140 U, the Special Black 6, the same 5, the same 4 A, the same 4, and the like.

Examples of pigments that can be used in the yellow ink composition include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 180, 185, 213 and the like.
Examples of pigments that can be used for magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, 209, C.I. I. Pigment violet 19 and the like.
Further, examples of pigments that can be used for cyan ink include C.I. I. And CI Pigment Blue 1, 2, 3, 15: 3, 15: 4, 60, 16, and 22.

The pigment addition amount of the ultraviolet curable ink composition in the invention is preferably in the range of about 0.1 to 25% by mass, more preferably in the range of about 0.5 to 15% by mass.
Further, from the viewpoint of the effect of suppressing color bleeding, the pigment contained in the color ink composition is preferably a yellow pigment.

  According to a preferred embodiment of the present invention, these pigments can be used as a pigment dispersion obtained by dispersing in a medium with a dispersant or a surfactant. As a preferable dispersant, a dispersant conventionally used for preparing a pigment dispersion, for example, a polymer dispersant can be used.

In the present invention, the mode diameter of the pigment contained in the black ink composition is from 80 nm to 250 nm, preferably from 100 nm to 200 nm. The mode particle size of the pigment contained in the ultraviolet curable color ink composition is 10 nm or more and less than 80 nm, preferably 30 nm or more and 60 nm or less. Here, the mode particle size represents the particle size having the largest content ratio in the pigment particles, and is, for example, a particle size obtained by particle size distribution measurement using a light scattering type particle size measuring device (such as Nanotrac 150 manufactured by Microtrac Inc.). It is obtained from the distribution curve.
In the present invention, since each pigment has a mode particle size in the above range, color bleeding at the time of printing by an ink jet method can be suppressed. This is because, when the pigments of the black ink composition and the color ink composition come into contact immediately after landing, heteroaggregation occurs due to the difference in the particle size of both pigments, so that the pigment diffuses further. It is presumed that this is suppressed and color mixing is suppressed.
In addition, black pigments develop a black color with a larger particle size, while other color pigments develop a more vivid color with a smaller particle size. This is also advantageous from the viewpoint of.
When the ink set of the present invention includes a plurality of color ink compositions, the mode particle diameter of the pigment contained in at least one of the color ink compositions may be 10 nm or more and less than 80 nm. In particular, the mode diameter of the yellow pigment is preferably 10 nm or more and less than 80 nm. This is because yellow having a large lightness difference from black has a remarkable effect of suppressing color bleed.

In the present invention, the black ink composition preferably contains a resin having a weight average molecular weight of 4,000 to 50,000. If the weight average molecular weight is in the above range, the type of resin is not particularly limited. For example, in the case of a commercially available product, Disperbyk 108, 116, 142, 145, 161, 164, 167, 168 manufactured by BYK (Big Chemie) is used. 171, 174, 182, 2020, 2025, EFKA 4008, 4010, 4020, 4047, 4060, 4300, 4330, 4340, 4400, 4403, 5054 manufactured by Ciba, Ajispar PA111, PB821, PB822, Lubrizol manufactured by Ajinomoto Co., Inc. Examples include Solsperse 13940 manufactured by the company. These resins may be used alone or in combination of two or more. The content is preferably 0.5% by mass to 20% by mass and more preferably 3% by mass to 7% by mass with respect to the total amount of the black ink composition, but is not particularly limited.
The resin contained in the black ink composition can suppress the occurrence of color bleed due to diffusion of the pigment into the gap between the pigments in the ink composition after landing. That is, the pigment contained in the black ink has a larger particle size (largest mode particle size) than the pigment contained in the color ink, and therefore, after landing, there is a gap between the black pigment pigments in the black image area. It is guessed. By including a resin having a weight average molecular weight of 4,000 to 50,000 in the black ink composition, the resin enters the gaps between the pigments, and the black pigments are accumulated while suppressing the gaps to form an image. it can. For this reason, it is possible to suppress the occurrence of color bleeding due to the diffusion of the color pigment in this portion.
Moreover, in order to exhibit this effect more, it is preferable that the resin is a straight chain having no branched structure in the molecule.

  The ultraviolet curing reaction type of the ink composition in the present invention is not particularly limited, but is preferably a radical polymerization method or a cationic polymerization method, and can be appropriately selected depending on the application. The reaction type polymerizable monomer and photopolymerization initiator will be described below.

(1) Radical polymerization type As the polymerizable monomer, a radical polymerizable monomer can be used, for example, an unsaturated tertiary amine-containing monomer having a basic functional group in the molecule, or an unsaturated ammonium salt. Examples thereof include monomers. Specifically, monovinylpyridines such as vinylpyridine, 2-methyl-5-vinylpyridine and 2-ethyl-5-vinylpyridine; dialkyl such as N, N-dimethylaminostyrene and N, N-dimethylaminomethylstyrene Styrenes having an amino group; N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminopropyl acrylate, Esters having a dialkylamino group of acrylic acid or methacrylic acid such as N, N-dimethylaminopropyl methacrylate, N, N-diethylaminopropyl acrylate, N, N-diethylaminopropyl methacrylate; Vinyl ethers having a dialkylamino group such as noethyl vinyl ether; N- (N ′, N′-dimethylaminoethyl) acrylamide, N- (N ′, N′-dimethylaminoethyl) methacrylamide, N- (N ′, N'-diethylaminoethyl) acrylamide, N- (N ', N'-diethylaminoethyl) methacrylamide, N- (N', N'-dimethylaminopropyl) acrylamide, N- (N ', N'-dimethylaminopropyl) ) Acrylamide or methacrylamide having a dialkylamino group such as methacrylamide, N- (N ′, N′-diethylaminopropyl) acrylamide, N- (N ′, N′-diethylaminopropyl) methacrylamide, or halogenated thereof Alkyl (alkyl group having 1 to 18 carbon atoms, salt as halogen) , Bromine, iodine), benzyl halides such as benzyl chloride or bromide, alkyl or aryl sulfonic acids such as methanesulfonic acid, benzenesulfonic acid or alkyl esters of toluenesulfonic acid (alkyl group having 1 to 18 carbon atoms), And quaternized with a known quaternizing agent such as dialkyl sulfate (alkyl group having 1 to 4 carbon atoms).

  Moreover, the unsaturated carboxylic acid monomer which has an acidic functional group in a molecule | numerator, unsaturated sulfonic acid monomer, unsaturated phosphoric acid monomer, etc. can be mentioned. Specifically, the unsaturated carboxylic acid monomer includes acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, 2-methacryloyloxymethyl succinic acid, etc. Unsaturated sulfonic acid monomers include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylic acid ester, bis- (3-sulfopropyl) -itaconic acid ester, etc. There are sulfuric acid monoesters of 2-hydroxyethyl (meth) acrylic acid, and unsaturated phosphoric acid monomers include vinylphosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, Diphenyl-2-methacryloilo Phenoxyethyl phosphate, dibutyl-2-acryloyloxyethyl phosphate, dibutyl-2-methacryloyloxyethyl phosphate, a dioctyl-2- (meth) acryloyloxyethyl phosphate and the like.

  Examples of the radical polymerizable monomer include (meth) acrylates, (meth) acrylamides, aromatic vinyls 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.

  Monofunctional (meth) acrylates include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-octyl (meth) acrylate, isoamyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, stearyl (Meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2- Ethylhexyl diglycol (meth) acrylate, butoxyethyl (meth) acrylate, methoxypropylene monoacrylate, 2-chloroethyl (meth) acrylate, 4-bromobutyl (meth) ) Acrylate, cyanoethyl (meth) acrylate, benzyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, alkoxymethyl (meth) acrylate, 2-ethylhexyl carbitol (meth) acrylate, Alkoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 2,2,2-tetrafluoroethyl (meth) acrylate, 1H , 1H, 2H, 2H-perfluorodecyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) Chlorate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, glycidyloxybutyl (meth) acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydro Furfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylic Rate, diethylaminopropyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, trimethylsilylpropyl (meth) acrylate, polyethylene oxide monomethyl ether (meth) acrylate, oligoethylene oxide monomethyl ether (meth) Acrylate, polyethylene oxide (meth) acrylate, oligoethylene oxide (meth) acrylate, oligoethylene oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, dipropylene glycol (meth) acrylate, polypropylene oxide monoalkyl ether ( (Meth) acrylate, oligopropylene oxide monoa Kill ether (meth) acrylate, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl ( (Meth) acrylate, perfluorooctylethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, EO-modified phenol (meth) acrylate, EO-modified cresol (meth) acrylate, EO-modified nonylphenol (meth) acrylate, Examples thereof include PO-modified nonylphenol (meth) acrylate and EO-modified-2-ethylhexyl (meth) acrylate.

  As the bifunctional (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl diacrylate, Neopentyl glycol di (meth) acrylate, 2,4-dimethyl-1,5-pentanediol di (meth) acrylate, butylethylpropanediol di (meth) acrylate, ethoxylated cyclohexanemethanol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, oligoethylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, 2-ethyl-2-butyl-butanediol di (meth) acrylate, hydroxypivalate neopentylglycol Di (meth) acrylate, EO-modified bisphenol A di (meth) acrylate, bisphenol F polyethoxydi (meth) acrylate, polypropylene glycol di (meth) acrylate, oligopropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) ) Acrylate, 2-ethyl-2-butyl-propanediol di (meth) acrylate, 1,9-nonanedi (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, tricyclodecane di (meth) acrylate, etc. Is mentioned.

  Trifunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) acrylate, di Pentaerythritol tri (meth) acrylate, trimethylolpropane tri ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, dipentaerythritol tri (meth) acrylate propionate, tri ((meta ) Acryloyloxyethyl) isocyanurate, hydroxypivalaldehyde-modified dimethylolpropane tri (meth) acrylate, sorbitol tri (meth) acrylate , Propoxylated trimethylolpropane tri (meth) acrylate, and the like ethoxylated glycerol triacrylate.

  Tetrafunctional (meth) acrylates include pentaerythritol tetra (meth) acrylate, sorbitol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, propionate dipentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (Meth) acrylate etc. are mentioned.

  Examples of pentafunctional (meth) acrylates include sorbitol penta (meth) acrylate and dipentaerythritol penta (meth) acrylate.

  Examples of hexafunctional (meth) acrylates include dipentaerythritol hexa (meth) acrylate, sorbitol hexa (meth) acrylate, phosphazene alkylene oxide modified hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, and the like. It is done.

  Examples of (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N -T-butyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl ( And (meth) acrylamide and (meth) acryloylmorpholine.

  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-methyl Styrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octyl Styrene, 4-octylstyrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allyl styrene, isopropenyl styrene, butenyl styrene, octenyl styrene, 4-t-butoxy Rubonirusuchiren, 4-methoxystyrene, and a 4-t-butoxystyrene.

  According to a preferred embodiment of the present invention, the addition amount of the radical polymerizable monomer in the ultraviolet curable ink composition is preferably in the range of about 70 to 90% by mass, more preferably in the range of about 75 to 85% by mass. is there.

As the photopolymerization initiator, a photo radical generator can be used. For example, benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6- Trimethylbenzoyldiphenylphosphine oxide, 6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like are preferably used, and other molecular cleavage types include 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyldimethyl ketal, 2-hydroxy-2 − Tyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopro Pan-1-one or the like may be used in combination, and further, by using a hydrogen abstraction type photopolymerization initiator, such as benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4′-methyl-diphenyl sulfide. Also good. Further, a molecular cleavage type and a hydrogen abstraction type photopolymerization initiator can be used in combination.
For the above photo radical generator, for example, trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N, N An amine that does not cause an addition reaction with the polymerizable component, such as dimethylbenzylamine and 4,4′-bis (diethylamino) benzophenone, can also be used in combination.

  According to a preferred embodiment of the present invention, the addition amount of the photo radical generator in the ultraviolet curable ink composition is preferably in the range of about 0.5 to 10% by mass, more preferably in the range of about 3 to 7% by mass. is there.

(2) Cationic polymerization type As the polymerizable monomer, a cationic polymerizable monomer can be used. For example, a compound having an oxetane ring (hereinafter referred to as an oxetane compound), a compound having an oxirane ring (hereinafter referred to as an oxetane ring). An oxirane compound), an epoxy compound, a vinyl ether compound, and the like.
The oxetane compound as the cationically polymerizable compound used in the present invention is a compound having one or more oxetane rings in the molecule. Specifically, 3-ethyl-3-hydroxymethyloxetane (trade name OXT101 manufactured by Toagosei Co., Ltd.), 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene (OXT121 etc.) ), 3-ethyl-3- (phenoxymethyl) oxetane (OXT211 etc.), di (1-ethyl-3-oxetanyl) methyl ether (OXT221 etc.), 3-ethyl-3- (2-ethylhexyloxymethyl) ) Oxetane (OXT212, etc.) can be preferably used, and in particular, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, di (1-ethyl-3-oxetanyl) methyl Ether can be preferably used. These can be used alone or in combination of two or more.
When an oxetane compound is used as the cationic polymerizable monomer, it is preferably contained in the ultraviolet curable ink composition in an amount of 5 to 95% by mass, more preferably 20 to 80% by mass.
Examples of the oxirane compound include epoxy compounds such as the following aromatic epoxides, alicyclic epoxides, and aliphatic epoxides.

A preferable aromatic epoxide is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, such as bisphenol A or an alkylene oxide thereof. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or its alkylene oxide adducts, and novolak-type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.
As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is preferable.
Preferred aliphatic epoxides include di- or polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or Diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or its alkylene oxide adduct, polyethylene glycol or its alkylene oxide adduct Diglycidyl ethers of polyalkylene glycols such as diglycidyl ethers, polypropylene glycols or diglycidyl ethers of adducts thereof Tel and the like. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.
Among these epoxides, in view of fast curability, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are particularly preferable. Hereinafter, an example of an alicyclic epoxide is shown.

In the present invention, one of the epoxides may be used alone, or two or more may be used in appropriate combination.
When an oxirane compound is used as the cationic polymerizable monomer, it is preferably contained in the ultraviolet curable ink composition in an amount of 5 to 95% by mass, more preferably 20 to 80% by mass.

  In the present invention, a vinyl ether compound may be used in combination as the cationic polymerizable compound. For example, ethylene glycol divinyl ether, ethylene glycol monovinyl ether, diethylene glycol divinyl ether, triethylene glycol monovinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexane Di- or trivinyl ether compounds such as dimethanol divinyl ether, hydroxyethyl monovinyl ether, hydroxynonyl monovinyl ether, trimethylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether And monovinyl ether compounds such as butyl, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl ether-o-propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, octadecyl vinyl ether Can be mentioned.

  As the photopolymerization initiator, a photoacid generator can be used. Specifically, as the latent cationic polymerizable catalyst, a quaternary ammonium salt represented by the following general formula (1), a phosphonium salt represented by the following general formula (2), the following general formula (3), (4) or It is at least one onium salt selected from the group consisting of a sulfonium salt represented by (5), a diazonium salt represented by the following general formula (6) and an iodonium salt represented by the following general formula (7).

(In General Formula (1), R ^{9 to} R ¹² are each an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 3 to 12 carbon atoms, an aryl group, an alkaryl group, or 1 to 20 carbon atoms. An alkanol group or a cycloalkyl group having 5 to 10 carbon atoms, which may be the same as or different from each other, may or may not have a substituent, and R ^{9 to} R ¹² The two may be bonded to each other to form a heterocycle having a heteroatom of N, P, O or S. Furthermore, X is BF ₄ , PF ₆ , AsF ₆ , SbF ₆ , SbCl ₆ , ( C ₆ F ₅ ) ₄ B, SbF ₅ (OH), HSO ₄ , p-CH ₃ C ₆ H ₄ SO ₃ , HCO ₃ , H ₂ PO ₄ , CH ₃ COO and monovalent selected from the group consisting of halogen atoms Represents the anion.)

(In General Formula (2), R ^{9 to} R ¹² and X are the same as R ^{9 to} R ¹² and X in General Formula (1), respectively.)

(In General Formula (3), R ^{9 to} R ¹¹ and X are the same as R ^{9 to} R ¹¹ and X in General Formula (1), respectively, and two of R ^{9 to} R ¹¹ are bonded to each other. And a heterocycle having N, P, O, or S as a heteroatom may be formed.)

(In General Formula (4), R ⁹ , R ¹⁰ and X are the same as R ⁹ , R ¹⁰ and X in General Formula (1), respectively, and R ⁹ and R ¹⁰ are bonded to each other to form N , P, O, or S may form a heterocycle, and Ar ¹ represents a monovalent aryl group that may or may not have a substituent, and Ar ² represents Represents a divalent arylene group which may or may not have a substituent.

(In General Formula (5), R ^{9 to} R ¹² and X are the same as R ^{9 to} R ¹² and X in General Formula (1), respectively, and Ar ¹ represents General Formula (4). is the same as Ar ¹ in, Ar ² is the same as Ar ² in the general formula (4).)

(In General Formula (6), Ar ¹ and X are the same as Ar ¹ in General Formula (4) and X in General Formula (1), respectively.)

(In the general formula (7), X is the same as X in the general formula (1), and Ar ³ and Ar ⁴ may be the same as or different from each other and may have a substituent. It is a monovalent aryl group that may not be present.)

Here, in the general formulas (1) to (5), the alkyl group having 1 to 20 carbon atoms as R ⁹ , R ¹⁰ , R ¹¹ or R ¹² may have a substituent. And a linear or branched alkyl group which may be omitted, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n- Pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group , Octadecyl group, nonadecyl group and eicosyl group. Further, as the ^{R 9,} R ^{10, R 11} or alkenyl group having 3 to 12 carbon atoms as ^{R 12,} an alkenyl group having optionally having a substituent, a good straight-chain or branched need not have For example, n-propenyl group, n-butenyl group, sec-butenyl group, tert-butenyl group, n-pentenyl group, sec-pentenyl group, hexenyl group, n-heptenyl group, sec-heptenyl group, octenyl Group, nonenyl group, decenyl group and uncenyl group. Examples of the aryl group as R ⁹ , R ¹⁰ , R ¹¹ or R ¹² include a substituted or unsubstituted phenyl group, naphthyl group or anthracene group, and a phenyl group is particularly preferable. Examples of the alkaryl group as R ⁹ , R ¹⁰ , R ¹¹ or R ¹² include those composed of the aforementioned alkyl group having 1 to 20 carbon atoms and an aryl group. Moreover, as said C9-20 alkanol group as said R < ⁹ >, R < ¹⁰ >, R < ¹¹ > or R < ¹² >, the linear or branched alkanol group which may or may not have a substituent is included. For example, ethanol group, n-propanol group, isopropanol group, n-butanol group, sec-butanol group, tert-butanol group, n-pentanol group, sec-pentanol group, 1-hexanol group, 1 -Heptanol group, 1-octanol group, 1-nonanol group, 1-decanol group, 1-undecanol group, 1-dodecanol group, 1-tridecanol group, 1-tetradecanol group, 1-pentadecanol group, 1- Hexadecanol group, 1-heptadecanol group, 1-octadecanol group, 1-nonadecanol group and 1-eicosa Such Lumpur group. Furthermore, the cycloalkyl group having 5 to 10 carbon atoms as R ⁹ , R ¹⁰ , R ¹¹ or R ¹² may have a branch which may or may not have a substituent. A cycloalkyl group is included, and examples thereof include a cyclopentyl group, a 2-methylcyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

On the other hand, in the general formulas (4) and (6), the monovalent aryl group which may or may not have a substituent as Ar ¹ is a substituted or unsubstituted phenyl group or naphthyl group. Is mentioned. In the general formulas (4) and (5), the divalent arylene group which may or may not have a substituent as Ar ² is a substituted or unsubstituted phenylene group or naphthylene group. Is mentioned. In the general formulas (1) to (6), examples of the substituent include halogen atoms such as fluorine atoms, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, sec- Alkyl groups having 1 to 8 carbon atoms, such as butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group and n-octyl group, cyclopentyl group A cycloalkyl group having 5 to 7 carbon atoms such as a cyclohexyl group and a cycloheptyl group, or a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, Pentyloxy group, isopentyloxy group, sec-pentyloxy group, hexyloxy group, Seo hexyloxy group, and an alkoxy group having 1 to 8 carbon atoms such as heptyloxy group and octyloxy group. In the general formula (7), Ar ³ and Ar ⁴ may be the same or different from each other, and are a monovalent aryl group that may or may not have a substituent. Examples of such a monovalent aryl group include a substituted or unsubstituted phenyl group, naphthyl group, or anthracene group, and a phenyl group is particularly preferable. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl. Group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group and other alkyl groups having 1 to 8 carbon atoms, cyclopentyl group, cyclohexyl group and cycloheptyl A cycloalkyl group having 5 to 7 carbon atoms such as a group, or a methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group, isopentyl Oxy group, sec-pentyloxy group, hexyloxy group, isohexyl Alkoxy group, and an alkoxy group having 1 to 8 carbon atoms such as heptyloxy group and octyloxy group.

  Examples of the quaternary ammonium salt represented by the general formula (1) include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium hydrogen sulfate, tetraethylammonium tetrafluoroborate, tetraethylammonium-p- Toluenesulfonate, N-benzyl-N, N-dimethylanilinium hexafluoroantimony, N-benzyl-N, N-dimethylanilinium tetrafluoride, N- (4-methoxybenzyl) -N, N-dimethylanily Antimony nium hexafluoride, antimony N-benzyl-N, N-dimethyltoluidinium hexafluoride, antimony N-benzylpyridinium hexafluoride, N-benzyl-4-cyanopyridinium hexafluoride Chimon, 4-cyano -N- (4- methoxybenzyl) pyridinium hexafluoroantimonate and the like.

  Specific examples of the phosphonium salt represented by the general formula (2) include ethyltriphenylphosphonium antimony hexafluoride and tetrabutylphosphonium antimony hexafluoride.

Examples of the sulfonium salt represented by the general formula (3), (4) or (5) include triphenylsulfonium boron tetrafluoride, triphenylsulfonium hexafluoride antimony, triphenylsulfonium hexafluoride arsenide, tri ( 4-methoxyphenyl) sulfonium arsenic hexafluoride, diphenyl (4-phenylthiophenyl) sulfonium arsenic hexafluoride, Adeka Opton SP-150 (manufactured by Asahi Denka Kogyo Co., Ltd., counter ion: PF ₆ ), Adeka Opton SP-170 (Asahi Denka Kogyo Co., Ltd., counter ion: SbF ₆ ), Adeka Opton CP-66 (Asahi Denka Kogyo Co., Ltd., counter ion: SbF ₆ ), Adeka Opton CP-77 (Asahi Denka Kogyo Co., Ltd., counter ion: SbF ₆ ) , Sun-Aid SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd., counter ion: S F _6), San-Aid SI-80L (Sanshin Chemical Industry Co., counterion: _SbF 6), San-Aid SI-100L (Sanshin Chemical Industry Co., counterion: _SbF 6), San-Aid SI-0.99 (three new chemical industry Co., Ltd., counter _{ion: SbF 6), CYRACURE UVI-} 6974 ( Union carbide Corp., counter _{ion: SbF 6), CYRACURE UVI-} 6990 ( Union carbide Corp., counter ion: _PF 6), UVI-508 (manufactured by General Electric), UVI-509 (manufactured by General Electric), FC-508 (manufactured by Minnesota Mining & Manufacturing), FC-509 (Minnesota Mining & Manufacturing) CD-1010 (Sartomer) , CD-1011 (manufactured by Sartomer Co., Ltd.) and CI series (manufactured by Nippon Soda Co., Ltd., counter _ion: PF _6, SbF 6), and the like.
Specific examples of the diazonium salt represented by the general formula (6) include AMERICURE (counter ion: BF ₄ ) manufactured by American Can and ULTRASET (counter ion: BF ₄ , PF ₆ ) manufactured by Asahi Denka Kogyo Co., Ltd. And so on.

Specific examples of the iodonium salt represented by the general formula (7) include diphenyliodonium hexafluoroarsenide, di-4-chlorophenyliodonium hexafluoroarsenide, di (4-bromophenyl) iodonium hexafluoroarsenide, phenyl ( 4-methoxyphenyl) iodonium hexafluoroarsenide, UVE series manufactured by General Electric, FC series manufactured by Minnesota Mining & Manufacturing, UV-9310C (counter ion: SbF ₆ ) manufactured by Toshiba Silicone, and Examples include Photoinitiator 2074 (counter ion: (C ₆ F ₅ ) ₄ B) manufactured by Rhône-Poulenc.

  The latent cationic polymerizable catalysts represented by the general formulas (1) to (7) are used alone or in combination of two or more.

  According to a preferred embodiment of the present invention, the addition amount of the photoacid generator in the ultraviolet curable ink composition is preferably in the range of about 0.5 to 10% by mass, more preferably in the range of about 2 to 5% by mass. is there.

The ultraviolet curable ink composition in the present invention can contain a polymerization accelerator in any reaction type.
Although it does not specifically limit as a polymerization accelerator, Darocur EHA, EDB (made by Ciba Specialty Chemicals) etc. are mentioned.
Moreover, it is preferable that the ultraviolet curable ink composition in this invention contains a thermal radical polymerization inhibitor. Thereby, the storage stability of the ink composition is improved. Examples of the thermal radical polymerization inhibitor include Irgastab UV-10, UV-22, (manufactured by Ciba Specialty Chemicals) and the like.

  Furthermore, the ultraviolet curable ink composition of the present invention can use a surfactant, and for example, it is preferable to use a polyester-modified silicone or a polyether-modified silicone as a silicone-based surfactant, and a polyether-modified polydimethylsiloxane or It is particularly preferable to use polyester-modified polydimethylsiloxane. Specific examples include BYK-347, BYK-348, BYK-UV3510, 3530, and 3570 (manufactured by Big Chemie Japan Co., Ltd.).

  In addition, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, and waxes can be added as necessary. .

The ultraviolet curable ink composition in the present invention undergoes a curing reaction by irradiation with ultraviolet rays.
The dose of ultraviolet rays, 10 mJ / cm ² or more, preferably 10,000 / cm ² or less, more preferably 50 mJ / cm ² or more, conducted at 6,000 mJ / cm ² or less. If it is the amount of ultraviolet irradiation within such a range, a sufficient curing reaction can be performed.

Examples of the ultraviolet irradiation include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low pressure mercury lamps, and high pressure mercury lamps.
For example, a commercially available product such as an H lamp, D lamp, or V lamp manufactured by Fusion System can be used.
Further, ultraviolet irradiation can be performed by an ultraviolet light emitting semiconductor element such as an ultraviolet light emitting diode (ultraviolet LED) or an ultraviolet light emitting semiconductor laser.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples. In addition, the value of the mode particle diameter described below is obtained from Microtrac Inc. It is the value measured by Nanotrac150 made by a company.

(Production of UV curable ink composition)
1. Production Method of Black Ink Composition 1 To 1 L beaker, 60 g of methoxypropylene monoacrylate and 4.0 g of resin (Disperbyk 2020 (weight average molecular weight; 15000) manufactured by Big Chemie) were added and a stirrer (TK Robot manufactured by PRIMIX Corporation). The mixture was stirred at 10,000 rpm for 30 minutes and completely dissolved. To the solution, 6.0 g of a black pigment (Carbon Black # 1000 manufactured by Mitsubishi Chemical Corporation) was added and stirred at 16,000 rpm for 2 hours to prepare a mill base. The mill base was dispersed with a sand grinder (Dynomill Co., Ltd., Shinmaru Enterprises Co., Ltd. zirconia beads φ0.3 mm, filling rate 80%, peripheral speed 20 m / sec) for 3 hours to prepare a pigment dispersion. The dispersion was subjected to pressure filtration with a cartridge filter (VNN-010 manufactured by Loki Techno Co., Ltd.) to obtain a filtrate. To the filtrate, 25 g of 1,6-hexanediol diacrylate, photopolymerization initiator (IRGACURE 819 (trade name, manufactured by Ciba Specialty Chemicals): 3 g, IRGACURE 127 (trade name, manufactured by Ciba Specialty Chemicals) ): 2 g) was added to obtain a black UV curable ink composition. The mode diameter of the pigment was 165 nm.

2. Production method of black ink composition 2 The black pigment of the black ink composition 1 was changed to Ciba Microlith Black CK, the addition amount was 12 g, and the addition amount of methoxypropylene monoacrylate was 54 g. Black ink composition 2 was produced in the same manner as black ink composition 1. The mode diameter of the pigment was 75 nm.

3. Production method of black ink composition 3 A black ink composition 3 was produced in the same manner as the black ink composition 1 except that the resin of the black ink composition 1 was changed to Solsperse 13940 (weight average molecular weight; 3000) manufactured by Lubrizol. did. The mode diameter of the pigment was 171 nm.

4). Production method of black ink composition 4 A black ink composition 4 was produced in the same manner as the black ink composition 1 except that the resin of the black ink composition 1 was changed to Disperbyke 161 (weight average molecular weight; 100,000) manufactured by Big Chemie. did. The mode diameter of the pigment was 194 nm.

5. Manufacturing method of black ink composition 5 The methoxypropylene monoacrylate of black ink composition 1 is OXT-211 manufactured by Osaka Organic Chemical Co., and 1,6-hexanediol diacrylate is Celoxide 2000 (vinylcyclohexene mono) manufactured by Daicel Chemical Industries, Ltd. A black ink composition 5 was prepared in the same manner as the black ink composition 1 except that the photopolymerization initiator was changed to 5 g of CPI-210S manufactured by San Apro Co., Ltd. The mode diameter of the pigment was 168 nm.

6). Production method of black ink composition 6 The black pigment of the black ink composition 5 was changed to Ciba Microlith Black CK, the addition amount was 12 g, and the addition amount of OXT-211 was 54 g. A black ink composition 6 was produced in the same manner as the ink composition 5. The mode diameter of the pigment was 79 nm.

7). Production method of black ink composition 7 A black ink composition 7 was produced in the same manner as the black ink composition 5 except that the resin of the black ink composition 5 was changed to Solsperse 13940 (weight average molecular weight; 3000) manufactured by Lubrizol. did. The mode diameter of the pigment was 174 nm.

8). Production method of black ink composition 8 A black ink composition 8 was produced in the same manner as the black ink composition 5 except that the resin of the black ink composition 5 was changed to Disperbyke 161 (weight average molecular weight; 100,000) manufactured by BYK Chemie. did. The mode diameter of the pigment was 199 nm.

9. Manufacturing method of black ink 9 The black pigment of black ink 1 is changed to Microlith Black CA made by Ciba, the addition amount is 12 g, the addition amount of methoxypropylene monoacrylate is 58 g, the addition amount of resin is 0 g, Otherwise, black ink 9 was prepared in the same manner as black ink 1. The mode diameter of the pigment was 162 nm.

10. Manufacturing method of black ink 10 The black pigment of black ink 5 was changed to Ciba Microlith Black CA, the addition amount was 12 g, the addition amount of OXT-211 was 58 g, the addition amount of resin was 0 g, etc. Made black ink 10 in the same manner as black ink 5. The mode diameter of the pigment was 161 nm.

11. Method for producing color ink composition 1 The black pigment of the black ink composition 2 was changed to the micro pigment 4G-K manufactured by Ciba, the resin addition amount was changed to 0 g, and the addition amount of methoxypropylene monoacrylate was changed to 64 g. A color ink composition 1 was produced in the same manner as the product 2. The mode particle size of the pigment was 45 nm.

12 Production method of color ink composition 2 The black pigment of the black ink composition 2 was changed to a black pigment of Ciba Microlith Yellow 4G-K, the resin addition amount was changed to 0 g, and the methoxypropylene monoacrylate addition amount was changed to 64 g. A color ink composition 2 was produced in the same manner as the product 2. The mode diameter of the pigment was 102 nm.

13. Production method of color ink composition 3 The black pigment of the black ink composition 5 was changed to the black pigment of Ciba Microlith Blue 4G-K, the resin addition amount was changed to 0 g, and the addition amount of OXT-211 was changed to 64 g. In the same manner as in Example 5, a color ink composition 3 was produced. The mode diameter of the pigment was 47 nm.

14 Method for Producing Color Ink Composition 4 Black ink composition except that the black pigment of black ink composition 5 is Microlith Yellow 4G-K manufactured by Ciba, the addition amount of resin is 0 g, and the addition amount of OXT-211 is 64 g. In the same manner as in Example 5, a color ink composition 4 was produced. The mode diameter of the pigment was 110 nm.

Example 1
1. Preparation of printed matter for evaluation Black ink 1 and color ink 1 are each filled in an ink cartridge of a UV curable inkjet printer (model number JF-1610, manufactured by Mimaki Engineering Co., Ltd.), and the ink cartridge filled with black ink 1 is used as a black ink for the printer. The ink cartridge filled with the color ink 1 was attached to the cartridge attachment location at the blue cartridge attachment location. A substrate (PET film manufactured by Toray Industries, Inc .: Model No. 125-E20) cut to A4 size is sucked and mounted on a printing stand, and the evaluation pattern shown in FIG. 1 (black line pattern on blue background) is applied to the film. Printed on top. There are two printing modes: high-speed printing mode (600 dpi × 600 dpi 4-pass CMYK color code UV irradiation setting 100% clear coating not available) and low-speed printing mode (1200 dpi × 1200 dpi 16-pass CMYK color code UV irradiation setting 100% clear coating not available). Implemented by type.
2. Evaluation criteria Visually observe the boundary between the black line and the blue background of the printed material, ◎ when color bleed is not recognized at all, ○ when color bleed is slightly recognized, and x when significant color bleed is recognized. did. The results are shown in Table 1.

(Example 2)
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 3 and the color ink composition 1, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Example 3)
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 4 and the color ink composition 1, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
Example 4
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 5 and the color ink composition 3, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Example 5)
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 7 and the color ink composition 3, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Example 6)
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 8 and the color ink composition 3, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Example 7)
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 9 and the color ink composition 1, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Example 8)
A printed matter for evaluation was prepared in the same manner as in Example 1 using the black ink composition 10 and the color ink composition 3, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
Using the black ink composition 2 and the color ink composition 1, a printed matter for evaluation was prepared in the same manner as in Example 1, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Comparative Example 2)
Using black ink composition 1 and color ink composition 2, mounting an ink cartridge filled with color ink on the yellow cartridge mounting location, making the evaluation pattern a black line pattern on a yellow background, black printed matter A printed matter for evaluation was prepared and evaluated in the same manner as in Example 1 except that the boundary between the line and the yellow ground was visually observed. The results are shown in Table 1.
(Comparative Example 3)
Using the black ink composition 6 and the color ink composition 3, a printed matter for evaluation was prepared in the same manner as in Example 1, and then evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 1.
(Comparative Example 4)
Using the black ink composition 5 and the color ink composition 4, a printed matter for evaluation was prepared in the same manner as in Comparative Example 2, and then evaluated according to the same evaluation criteria as in Comparative Example 2. The results are shown in Table 1.

  From Table 1, when the mode diameter of the pigment contained in the black ink composition and the mode diameter of the pigment contained in the color ink composition are within the specified range, the printing speed is not limited. It was confirmed that an image with suppressed color bleeding was formed. Further, it was confirmed that color bleeding was further suppressed when a black ink composition containing a resin having a molecular weight within a specified range was used.

Claims (4)

An ink set for ink jet recording comprising an ultraviolet curable black ink composition and at least one ultraviolet curable color ink composition,
Each ink composition contains a pigment, a polymerizable monomer and a photopolymerization initiator,
The mode diameter of the pigment contained in the ultraviolet curable black ink composition is 80 nm or more and 250 nm or less,
An ink set for inkjet recording, wherein a mode particle diameter of a pigment contained in at least one of the ultraviolet curable color ink compositions is 10 nm or more and less than 80 nm.   The ultraviolet curable ink set for ink jet recording according to claim 1, wherein the ultraviolet curable black ink composition further contains a resin having a weight average molecular weight of 4,000 to 50,000.   3. The ink set for ink jet recording according to claim 1, wherein the polymerizable monomer is a radical polymerizable monomer, and the photopolymerization initiator is a photo radical generator.   3. The ink set for ink jet recording according to claim 1, wherein the polymerizable monomer is a cationic polymerizable monomer, and the photopolymerization initiator is a photoacid generator.

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