JP2006131884A - Energy ray-curable ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy ray-curable ink composition which has a low viscosity without dilution with a diluent solvent, exhibits good preservation stability and a good pigment-dispersing property when a coloring material is a pigment, is excellent in continuous jetting stability onto a recording medium, exhibits good curability with less energy consumption of an integrated light quantity of at most 150 mJ/cm<SP>2</SP>, gives good printing qualities on a non-absorbing recording medium and is particularly excellent in adhesion to a recording medium base material. <P>SOLUTION: The energy ray-curable ink composition comprises the coloring material, a monomer and a photopolymerization initiator, and contains an acrylamide derivative as the monomer, where the content of the acrylamide derivative is 10-90 wt% in the whole ink composition, and the viscosity of the whole ink composition is 3-35 mPa s at 25°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an energy ray curable ink composition, mainly an ink composition which is printed by an ink jet recording method and is cured by irradiation with an energy ray, particularly an ultraviolet ray curable ink composition.

In the ink jet recording method, printing is performed by ejecting liquid ink from a nozzle toward a recording medium using pressure, heat, an electric field or the like as a driving source. Such a recording method has a low running cost, can improve image quality, and can print various inks such as water-based and oil-based inks.

Recently, the image forming method of the ink jet recording method can obtain the same image quality as the silver salt photographic method and can be very inexpensive, so that it can be used for large advertisements that require a large image area. There are significant economic benefits for users who change frequently.

As an ink composition applied to this ink jet recording method, an ultraviolet curable ink composition of a type that is cured by irradiation with energy rays in a specific wavelength region, particularly by irradiation with ultraviolet rays (UV) is known. The main components of the ultraviolet curable ink composition include, for example, an ultraviolet curable monomer, a pigment or dye as a coloring material (coloring agent), and a photopolymerization initiator, and various additives as necessary. There is also a case to let you.

However, the viscosity of this ultraviolet curable ink composition usually exceeds 35 mPa · s at 25 ° C. In order to adopt the current ink jet recording method, the viscosity of the ink must be 35 mPa · s or less, and preferably 20 mPa · s or less.

In order to realize such a low viscosity, an ultraviolet curable ink composition using a volatile organic solvent such as ethyl lactate and butyl acetate as a diluent solvent together with an ultraviolet curable monomer, a color material and a photopolymerization initiator is provided. Are known. However, in such an ink composition, volatilization of a diluting solvent such as VOC (volatile organic compound) is likely to deteriorate the working environment and the natural environment, and the diluting solvent remains after ultraviolet curing. There is a problem that the film properties of the printed matter are likely to deteriorate, and in particular, the adhesion of the recording medium to the base material is deteriorated.

UV curable ink compositions that use various vinyl compounds, (meth) acrylic acid alkyl esters, polyfunctional (poly) alkoxy acrylates, etc. as UV curable monomers and reduce the use of diluent solvents have also been proposed. (See Patent Documents 1 to 3).
Japanese Patent Laid-Open No. 5-214279 Japanese Patent Laid-Open No. 5-214280 Special Table 2000-504778

However, the proposed ultraviolet curable ink composition generally has low monomer reactivity, and is not sufficiently cured due to oxygen inhibition with a small amount of energy with an integrated light quantity of 150 mJ / cm ² or less. There are limits to use in high-speed printing applications.

Increasing the amount of photoinitiator improves curability, but the solubility of the photoinitiator in the monomer is limited, insufficient to obtain sufficient curability, and unreacted photopolymerization is initiated. The agent remains and tends to adversely affect the properties of the cured film.

In view of the above circumstances, the present invention has a low viscosity without using a diluting solvent, storage stability, good pigment dispersibility when the colorant is a pigment, and continuous ejection stability to a recording medium. It is excellent and exhibits good curability even with low energy of less than 150 mJ / cm ^{2 in} accumulated light quantity, and good print quality can be obtained even for non-absorbent recording media. It is an object of the present invention to provide an energy beam curable ink composition having excellent properties.

As a result of intensive studies to overcome the above problems, the present inventors have found that when a specific amount of an acrylamide derivative is used as an energy ray-curable monomer, the viscosity is low even without dilution with a diluting solvent, and the storage stability. When the coloring material is a pigment, the pigment dispersibility is good, the continuous discharge stability to the recording medium is excellent, and the curability is good even at low energy with an integrated light quantity of 150 mJ / cm ² or less. It has been found that an energy ray curable ink composition can be obtained with respect to an absorptive recording medium, and in particular, an energy ray curable ink composition having excellent adhesion to a recording medium substrate, and the present invention has been completed. It is a thing.

That is, the present invention is an energy ray curable ink composition containing a coloring material, a monomer, and a photopolymerization initiator and substantially free of a diluent solvent, containing an acrylamide derivative as a monomer, The amount of the ink composition is 10 to 90% by weight in the whole ink composition, and the viscosity of the whole ink composition is 3 to 35 mPa · s at 25 ° C. is there.

In addition, the present invention includes an ink composition having the above-described constitution in which the viscosity of the entire ink composition is 3 to 20 mPa · s at 25 ° C., and a trifunctional or higher polyfunctional acrylate monomer as a monomer. The amount of the ink composition is 10 to 50% by weight based on the total amount of the ink composition, the ink composition having the above-described structure comprising two or more photopolymerization initiators, and 2-methyl- 1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one and an ink composition having the above-described structure containing at least a compound selected from thioxanthones; 1 to 20% by weight of the entire composition, the ink composition having the above-described configuration, the ink composition having the above-described configuration in which the coloring material is an organic pigment and / or an inorganic pigment, an organic pigment and / or And the amount of the inorganic pigment is 1 to 10% by weight in the whole ink composition, the ink composition having the above configuration containing the polymer compound as a pigment dispersant, and the amount of the polymer compound. , An ink composition having the above-described configuration of 5 to 150% by weight with respect to the organic pigment and / or the inorganic pigment, and an ink composition having the above-described configuration that is cured at an integrated light amount of 150 mJ / cm ² or less. Further, the present invention relates to the ink composition having the above-described configurations used in the ink jet recording system.

As described above, in the present invention, by using a specific amount of an acrylamide derivative as an ultraviolet curable monomer, the viscosity is low without using a diluting solvent, the storage stability, and the pigment dispersibility when the coloring material is a pigment. In addition, it has excellent continuous ejection stability to the recording medium, exhibits good curability even at low energy with an integrated light quantity of 150 mJ / cm ² or less, and prints well on non-absorbing recording media. It is possible to provide an energy beam curable ink composition that is high in quality and particularly excellent in adhesion to a recording medium substrate.

In the present invention, an acrylamide derivative is used as the energy ray-curable monofunctional monomer. By using an acrylamide derivative, it is possible to obtain excellent curability that is sufficiently low-viscosity at room temperature without using a diluting solvent, and that cures quickly even at low energy with an integrated light quantity of 150 mJ / cm ² or less. . On the other hand, when an ordinary (meth) acrylate monomer is used as the monofunctional monomer, the above curability is hardly obtained even if an ink composition having a low viscosity at room temperature is obtained.

Acrylamide derivatives include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide, and N, N-dihexyl. (Meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-hexyl (meth) acrylamide, (meth) acryloylmorpholine, N, N-dimethylaminomethyl (Meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminohexyl (meth) acrylamide, N, N-diethylaminomethyl (meth) acrylic Bromide, N, N-diethylaminoethyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-diethylamino-hexyl (meth) acrylamide.

Among these acrylamide derivatives, one of them can be used alone, or two or more can be mixed and used. Among these, N, N-dimethylacrylamide, N, N-diethylacrylamide, acryloylmorpholine and the like are particularly preferably used.

In the present invention, the amount of the acrylamide derivative used is 10 to 90% by weight, preferably 20 to 80% by weight, based on the entire ink composition. If it is less than 10% by weight, it is difficult to sufficiently reduce the viscosity of the ink composition, and if it exceeds 90% by weight, the amount of other compounding components is reduced by that amount, which tends to cause a decrease in curability and the like.

In the present invention, a trifunctional or higher polyfunctional acrylate monomer is usually used as an energy ray-curable monomer together with an acrylamide derivative in a ratio of 10 to 50% by weight, particularly 20 to 40% by weight, in the entire ink composition. It is desirable to use in.

When the amount of the trifunctional or higher polyfunctional acrylate monomer is less than the above, or when the bifunctional polyfunctional acrylate monomer is used instead of the trifunctional or higher polyfunctional acrylate monomer, the curability of the ink composition is reduced. It may be damaged, and sufficient curability may not be obtained at a low energy with an integrated light quantity of 150 mJ / cm ² or less.

Examples of the trifunctional or higher polyfunctional acrylate monomer include dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, hexafunctional monomers such as modified products thereof, dipentaerythritol hydroxypenta (meth) ) Acrylate, pentafunctional monomers such as caprolactone-modified dipentaerythritol hydroxypenta (meth) acrylate, tetrafunctional such as ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate Monomers, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, caprolact And trifunctional monomers such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, and propoxylated glyceryl tri (meth) acrylate. .

Among these polyfunctional acrylate monomers, one of them is used alone, or two or more of them are used in combination. Of these, dipentaerythritol hexaacrylate and dipentaerythritol hydroxypentaacrylate are particularly preferably used.

In the present invention, in addition to the monomer component described above, a bifunctional acrylate monomer can be used in combination as an optional component, and a monofunctional acrylate monomer other than an acrylamide derivative can also be used in combination. However, the amount of these optional components used should be 30% by weight or less, particularly 10% by weight or less in the entire ink composition so as not to impair the effects of the present invention. Is desirable.

Examples of the bifunctional acrylate monomer include hydroxypivalate neopentyl glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, trimethylolpropane (meth) acrylic acid benzoate, diethylene glycol di (meth) acrylate, Ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol (200) di (meth) acrylate, polyethylene glycol (400) di (meth) acrylate, polyethylene glycol (600) di (meth) acrylate, Polyethylene glycol (1000) di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate Polypropylene glycol (400) di (meth) acrylate, polypropylene glycol (700) di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butane Diol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate Bisphenol A ethylene oxide adduct di (meth) acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, and the like.

Monofunctional acrylate monomers include amyl (meth) acrylate, isoamyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, Isomyristyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, neopentyl glycol (meta ) Acrylic acid benzoate, butoxyethyl (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, Toxi-polyethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate, nonylphenol ethylene oxide adduct (meth) acrylate, tetrahydrofurfuryl (meth) Acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (Meth) acryloyloxyethyl-succinic acid, 2- (meth) acryloyloxyethyl-phthalic acid, 2- (meth) acryloyloxyethyl-2-hydroxy Ethyl - and phthalic acid, acrylate monomers imparted with functional groups of these phosphorus and fluorine and the like.

In the present invention, a photopolymerization initiator is used. As photopolymerization initiators, conventionally known initiators such as aryl alkyl ketones, oxime ketones, acyl phosphine oxides, acyl phosphonates, S-phenyl thiobenzoate, titanocene, aromatic ketones, thioxanthones, benzyl, quinone derivatives, ketocoumarins, etc. Any agent can be used.

For example, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane-1 -One, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,2-dimethoxy-1 , 2-diphenylethane-1-one, 1,2-octanedione- [4- (phenylthio) -2- (o-benzoyloxime)], bis (2,6-dimethoxybenzoyl) -2,4,4- Trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-phosphine oxide, 2,4-diethylthioxa Ton, 2-chlorothioxanthone, isopropylthioxanthone, there is [4- (methyl) phenyl] phenyl methanone or the like.

Among these photopolymerization initiators, one of them can be used alone, but preferably two or more are mixed and used. Among them, a photopolymerization initiator containing at least 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one and a compound selected from thioxanthones is particularly preferably used. .

In the present invention, the amount of the photopolymerization initiator used is 1 to 20% by weight, preferably 2 to 15% by weight, based on the whole ink composition. If it is less than 1% by weight, it is difficult to satisfy the curability by irradiation with energy rays such as ultraviolet rays, and if it exceeds 20% by weight, unreacted components remain and the print quality tends to be impaired.

In the present invention, various known dyes can be used as the color material, but it is desirable to use a pigment composed of an inorganic pigment and / or an organic pigment from the viewpoint of light resistance.

These pigments are generally used in a proportion of 1 to 10% by weight, preferably 2 to 7% by weight, more preferably 3 to 6% by weight in the whole ink composition. If the amount is too small, the coloring power is insufficient. If the amount is too large, the viscosity increases, and the fluidity of the ink tends to be impaired.

Moreover, in order to improve the dispersibility of a pigment, you may use together an appropriate pigment derivative. For example, pigment derivatives having a dialkylaminoalkyl group, pigment derivatives having a dialkylaminoalkylsulfonic acid amide group, and the like are preferably used.

Inorganic pigments include titanium oxide, zinc oxide, zinc oxide, tripon, iron oxide, aluminum oxide, silicon dioxide, kaolinite, montmorillonite, talc, barium sulfate, calcium carbonate, silica, alumina, cadmium red, red bean, molybdenum red, Chrome vermilion, molybdate orange, yellow lead, chrome yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, pyridiane, cobalt green, titanium cobalt green, cobalt chrome green, ultramarine blue, ultramarine blue, bituminous, cobalt blue , Cerulean blue, manganese violet, cobalt violet, mica.

Examples of organic pigments include azo, azomethine, polyazo, phthalocyanine, quinacridone, anthraquinone, indigo, thioindigo, quinophthalone, benzimidazolone, and isoindoline pigments. Carbon black made of acidic, neutral or basic carbon is also used. Furthermore, hollow particles of crosslinked acrylic resin or the like can also be used as a pigment.

Examples of the pigment in the cyan ink composition include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 16, 22, 60, and the like. Among these, from the viewpoints of weather resistance, coloring power, etc., C.I. I. One or a mixture of two or more selected from CI Pigment Blue 15: 3 and 15: 4 is preferable.

Examples of the pigment in the magenta ink composition include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, 209, 254, C.I. I. Pigment violet 19 and the like. Among these, from the viewpoints of weather resistance, coloring power, etc., C.I. I. Pigment red 122, 202, 209, 254, C.I. I. One or a mixture of two or more selected from Pigment Violet 19 is preferred.

Examples of the pigment in the yellow ink composition include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 130, 138, 139, 147, 150, 151, 154, 155, 180, 185, 213, 214 and the like. Among these, from the viewpoint of weather resistance and the like, C.I. I. One or a mixture of two or more selected from CI Pigment Yellow 74, 83, 109, 110, 120, 128, 138, 139, 150, 151, 154, 155, 213, 214 is preferable.

As pigments in the black ink composition, HCF, MCF, RCF, LFF, SCF manufactured by Mitsubishi Chemical Corporation, Monarch, Regal, manufactured by Cabot, Color Black manufactured by Degussa Huls, Special Black, Printex, Tokai Carbon Co., Ltd. Examples include Toka Black made by Columbia and Raven made by Columbia. Among these, in particular, HCF # 2650, # 2600, # 2350, # 2300, MCF # 1000, # 980, # 970, # 960, MCF88, LFFMA7, MA8, MA11, MA77, MA100, Degussa manufactured by Mitsubishi Chemical Corporation -One or a mixture of two or more selected from Hulex Printex 95, 85, 75, 55, 45 and the like is preferable.

The energy ray curable ink composition of the present invention contains the above-described colorant, acrylamide derivative and photopolymerization initiator, and usually contains a trifunctional or higher polyfunctional monomer, and further contains a bifunctional monomer or acrylamide as necessary. It contains a monofunctional monomer other than a derivative and substantially does not contain a diluting solvent.

Here, the fact that the diluent solvent is not substantially contained does not contain the diluent solvent at all, or even if a volatile organic solvent may be contained as an impurity, the volatilization deteriorates the working environment and the natural environment. It means that it is suppressed to a very small amount.

The diluted solvent means an organic solvent having a boiling point usually in the range of 50 to 200 ° C. For example, lactic acid esters, acetic acid esters, propionic acid esters, butyric acid esters, (poly) ethylene glycol ethers / esters, (poly) propylene glycol ethers / esters, etc., methyl ethyl ketone, cyclohexane, Various known organic solvents such as toluene and xylene are included.

The energy ray curable ink composition of the present invention can be prepared by various methods, but when a pigment is used as a color material, it is desirable to prepare it by the following method.

First, an inorganic pigment or / and an organic pigment and a part of an acrylamide derivative as a diluting monomer are premixed, a container drive medium mill such as a ball mill, a centrifugal mill, a planetary ball mill, a high-speed rotating mill such as a sand mill, a stirring tank A primary dispersion is obtained by stirring and mixing with a simple dispersing machine such as a medium stirring mill such as a mold mill or a disper.

Next, the remaining acrylamide derivative, a trifunctional or higher polyfunctional monomer that is a highly crosslinkable monomer, and a photopolymerization initiator are added to this primary dispersion, and three-one motor, magnetic stirrer, disper, homogenizer, etc. Mix evenly using a simple stirrer. You may mix using mixers, such as a line mixer. Moreover, you may mix using dispersers, such as a bead mill and a high-pressure injection mill, for the purpose of making a precipitation particle finer.

In preparing the primary dispersion, it is usually desirable to use a pigment dispersant. The pigment dispersant is excellent in affinity with the pigment and has a function of stabilizing the dispersion.

As the pigment dispersant, an ionic or nonionic surfactant or an anionic, cationic or nonionic polymer compound is used. From the viewpoint of dispersion stability, a polymer compound, particularly a polymer compound containing a cationic group or an anionic group is preferred. That is, the pigment dispersant preferably contains at least one of a cationic group or an anionic group that is a pigment adsorption site in order to stabilize the dispersion by the acid-base interaction between the pigment and the dispersant. Thus, it is desirable to adjust the kind and amount of the cationic group or anionic group in the dispersant.

As the pigment dispersant, SOLPERSE manufactured by Zeneca, DISPERBYK manufactured by BYK Chemie, EFKA manufactured by Fuka Additives, etc. are preferable. Of these, DISPERBYK161, 162, 168, EFKA4050, 4055, 4060 and the like are preferable, and DISPERBYK168 which is not diluted with a diluting solvent is more preferable. These are preferably used in accordance with the types of pigments and monomers used.

For pigment dispersants that are commercially available with low-boiling organic solvents such as toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, etc., when used as they are, the diluent solvent is contained in the ink. It will remain. For this reason, for these pigment dispersants, it is necessary to remove the diluting solvent in advance. As a method for removing the diluted solvent, a vacuum distillation method, a reprecipitation method or the like is used.

In the present invention, when a pigment dispersant composed of a polymer compound is used, the amount of the pigment dispersant used varies depending on the type of organic pigment or / and inorganic pigment, dispersion conditions, etc., but usually the organic pigment or / and It is preferable to set it as 5-150 weight% with respect to an inorganic pigment. In particular, when using an organic pigment, it is more preferable to set it as 40 to 150 weight%, and when using an inorganic pigment, it is more preferable to set it as 5 to 60 weight%.

The energy ray-curable ink composition of the present invention thus prepared can suppress polymerization due to heat or light during storage and improve storage stability by adding a polymerization inhibitor, if necessary. Can do.

Various compounds are known as polymerization inhibitors, but those widely blended in general polymerizable compositions can be used as they are. For example, phenolic antioxidants, hindered amine light stabilizers, phosphorus antioxidants, hydroquinone monoalkyl ethers widely used for (meth) acrylic monomers, and the like can be used.

Specific examples of hydroquinone monomethyl ether, hydroquinone, t-butylcatechol, pyrogallol, and trade names made by Ciba include TINUVIN111 FDL, TINUVIN123, TINUVIN144, TINUVIN292, TINUVIN XP40, TINUVIN XP60, and the like.

Among such compounds, one of them can be used alone, or two or more can be mixed and used. Hydroquinone monomethyl ether is particularly preferably used.

These polymerization inhibitors, when used in excess, inhibit the curability due to irradiation of energy rays such as ultraviolet rays, so that they do not inhibit this curability and can prevent polymerization at the time of preparation and storage of the ink composition. There is a need to. Usually, it is preferable to set it as 200-20,000 ppm, and it is more preferable to set it as 500-2,000 ppm.

In the energy ray curable ink composition of the present invention, if necessary, a surfactant, a surface conditioner, a leveling agent, an antifoaming agent, an antioxidant, a pH adjuster, a charge imparting agent, a disinfectant, an antiseptic, Known general additives such as deodorizers, charge control agents, wetting agents, anti-skinning agents, fragrances, and pigment derivatives can be blended as optional components. As the blending amount, a known general use amount can be selected according to the type.

The energy beam curable ink composition of the present invention has the above-described configuration, and the viscosity of the entire ink composition is in the range of 3 to 35 mPa · s at 25 ° C., particularly preferably in the range of 3 to 20 mPa · s. It is characterized by.

Further, the surface tension of the ink composition at 25 ° C. is usually in the range of 20 to 40 mN / m, particularly preferably in the range of 25 to 35 mN / m.

Further, when the color material is composed of an organic pigment and / or an inorganic pigment, the dispersion average particle diameter of the pigment particles is in the range of 20 to 200 nm, particularly preferably in the range of 50 to 160 nm. If the dispersion average particle size is less than 20 nm, the fine particles may cause the printed matter to lack light resistance, and if it exceeds 200 nm, the printed matter may lack fineness.

As described above, according to the energy ray curable ink composition of the present invention, no dilution solvent is used, the viscosity is low, the pigment dispersibility is good when the colorant is a pigment, and the ink is being stored. In addition, it has good storage stability without causing problems such as an increase in viscosity during use or precipitation of pigment. For this reason, in the ink jet recording method, a stable ejection property can be obtained at room temperature, and the continuous ejection stability is excellent.

In addition, by irradiating energy rays such as ultraviolet rays at the time of printing, it is possible to quickly cure by irradiation with low energy of particularly less than 150 mJ / cm ² of the integrated light amount of ultraviolet rays at 365 nm, and the curability is improved in each stage. It is excellent. Furthermore, good print quality can be obtained even for non-absorbent recording media, and in particular, since no diluting solvent is used, the adhesiveness to the recording medium substrate is excellent.

In the present invention, active energy rays such as ultraviolet rays are used for curing after ejecting the ink composition by the ink jet recording method.

It is desirable to irradiate the active energy ray for 1 to 1,000 ms immediately after being discharged onto the substrate of the recording medium. In order to make it less than 1 ms, the distance between the head and the light source is too short, which may lead to an unexpected situation due to energy irradiation to the head. On the other hand, if it exceeds 1,000 ms, the image quality deteriorates due to ink bleeding in multiple colors.

As the irradiation light source, a high-pressure mercury lamp, a low-pressure mercury lamp, a cold cathode tube, a black light, an ultraviolet LED, an ultraviolet laser, flash light, or the like is used as the irradiation light source. Moreover, it can also harden | cure using 2 types of light sources from which a light source and illumination intensity differ. At this time, the cumulative amount of ultraviolet light may be as low as 150 mJ / cm ² or less as described above.

In the present invention, it is possible to arbitrarily adopt a usage form such as forming an image by simultaneously using four or more energy beam curable ink compositions containing at least cyan, magenta, yellow and black by the above printing method.

Next, examples of the present invention will be described and described in more detail. However, the composition of the following ultraviolet curable ink composition is merely an example, and does not limit the scope of the present invention. Hereinafter, “parts” means parts by weight.

In a 100 cc plastic bottle, 20.0 parts “HOSTAPERM BLUE P-BFS” (Clariant, copper phthalocyanine blue pigment), “DISPERBYK168” (Bic Chemie, amine polymer dispersant) as a pigment dispersant33. 3 parts, 46.7 parts of dimethylacrylamide “DMAA” (manufactured by Kojin Co., Ltd.) as an acrylamide derivative, and 100 parts of zirconia beads having a diameter of 0.3 mm are weighed and dispersed for 2 hours using a paint conditioner (manufactured by Toyo Seiki Co., Ltd.). did.

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative and “light acrylate DPE-6A” as a polyfunctional monomer (manufactured by Kyoeisha Chemical Co., Ltd., dipentaerythritol hexa) Acrylate, hexafunctional monomer) 19.5 parts, “IRGACURE907” {manufactured by Ciba Specialty Chemicals Co., Ltd., 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane as a photopolymerization initiator -1-one} 9.0 parts, 1.0 part of “DET-X” (manufactured by Nippon Kayaku Co., Ltd., 2,4-diethylthioxanthone) was added, and after stirring for 30 minutes with a magnetic stirrer, a glass filter ( Using a Kiriyama Seisakusho Co., Ltd.), suction filtration was performed to prepare an ultraviolet curable ink composition A.

In a 100 cc plastic bottle, 20.0 parts “HOSTAPER PIN EB trans” (Clariant, quinacridone pigment), 46.7 parts “DISPERBYK168” as a pigment dispersant, 33.3 parts “DMAA” as an acrylamide derivative, diameter 100 parts of 0.3 mm zirconia beads were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

Using the dispersion obtained by dispersing in this way, an ultraviolet curable ink composition B was prepared in the same manner as in Example 1.

In a 100 cc plastic bottle, 20.0 parts of “E4GN-GT” (manufactured by Bayer, nickel-containing azo pigment), 26.6 parts of “DISPERBYK168” as a pigment dispersant, 53.4 parts of “DMAA” as an acrylamide derivative, diameter 100 parts of 0.3 mm zirconia beads were measured and dispersed for 2 hours using a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

Using the dispersion obtained by dispersing in this way, an ultraviolet curable ink composition C was prepared in the same manner as in Example 1.

In a 100 cc plastic bottle, 20.0 parts “MA-8” (manufactured by Mitsubishi Chemical Corporation, acidic carbon black pigment), 26.6 parts “DISPERBYK168” as a pigment dispersant, and 53.4 parts “DMAA” as an acrylamide derivative 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours using a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

Using the dispersion obtained by dispersing in this manner, an ultraviolet curable ink composition D was prepared in the same manner as in Example 1.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPER BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and acryloylmorpholine “ACMO” ( 46.7 parts by Kojin Co., Ltd.) 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours using a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

In 25.0 parts of the dispersion obtained in this way, 45.5 parts of “ACMO” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ Add 9.0 parts of IRGACURE907 ”and 1.0 part of“ DET-X ”, and stir for 30 minutes with a magnetic stirrer, and then suction filter using a glass filter (manufactured by Kiriyama Seisakusho) to form an ultraviolet curable ink composition. Product E was prepared.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and “DMAA” 46.7 as an acrylamide derivative 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

In 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative and “light acrylate PE-4A” (poly-erythritol tetraacrylate, manufactured by Kyoeisha Chemical Co., Ltd.) as a polyfunctional monomer. 19.5 parts of tetrafunctional monomer), 9.0 parts of “IRGACURE907” and 1.0 part of “DET-X” are added as photopolymerization initiators, and after stirring for 30 minutes with a magnetic stirrer, glass filter (Kiriyama Seisakusho) Was used for suction filtration to prepare an ultraviolet curable ink composition F.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and diethylacrylamide “DEAA” as an acrylamide derivative ( 46.7 parts of Kojin Co., Ltd.) and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours using a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DEAA” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ Add 9.0 parts of IRGACURE907 ”and 1.0 part of“ DET-X ”, and stir for 30 minutes with a magnetic stirrer, and then suction filter using a glass filter (manufactured by Kiriyama Seisakusho) to form an ultraviolet curable ink composition. Product G was prepared.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and dimethylacrylamide “DMAA” 46 as an acrylamide derivative .7 parts and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ 10.0 parts of IRGACURE907 "was added, and after stirring for 30 minutes with a magnetic stirrer, suction filtration was performed using a glass filter (manufactured by Kiriyama Seisakusho) to prepare an ultraviolet curable ink composition H.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and dimethylacrylamide “DMAA” 46 as an acrylamide derivative .7 parts and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ "IRGACURE819" [Ciba Specialty Chemicals Co., Ltd., bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide] 9.0 parts, "KAYACURE BMS" {Nippon Kayaku Co., Ltd., [4- ( Methylphenylthio) phenyl] phenylmethanone} 1.0 part was added, and after stirring for 30 minutes with a magnetic stirrer, suction filtration was performed using a glass filter (manufactured by Kiriyama Seisakusho), and UV curable ink composition I Was prepared.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and dimethylacrylamide “DMAA” 46 as an acrylamide derivative .7 parts and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ Add IRGACURE907 ”5.0 parts,“ IRGACURE184 ”(Ciba Specialty Chemicals Co., Ltd., 1-hydroxy-cyclohexyl-phenyl-ketone) 3.0 parts,“ KAYACURE BMS ”2.0 parts, magnetic stirrer. Then, after stirring for 30 minutes, suction filtration was performed using a glass filter (manufactured by Kiriyama Seisakusho) to prepare an ultraviolet curable ink composition J.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and dimethylacrylamide “DMAA” 46 as an acrylamide derivative .7 parts and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ IRGACURE819 "10.0 parts was added, and after stirring for 30 minutes with a magnetic stirrer, suction filtration was performed using a glass filter (manufactured by Kiriyama Seisakusho) to prepare an ultraviolet curable ink composition K.

In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and dimethylacrylamide “DMAA” 46 as an acrylamide derivative .7 parts and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

To 25.0 parts of the dispersion thus obtained, 45.5 parts of “DMAA” as an acrylamide derivative, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ 10.0 parts of IRGACURE 184 "was added, and after stirring for 30 minutes with a magnetic stirrer, suction filtration was performed using a glass filter (manufactured by Kiriyama Seisakusho) to prepare an ultraviolet curable ink composition L.

Instead of “DET-X” (manufactured by Nippon Kayaku Co., Ltd., 2,4-diethylthioxanthone), which is one of the photopolymerization initiators, “CTX” (manufactured by Nippon Kayaku Co., Ltd., 2-chlorothioxanthone) is used. An ultraviolet curable inkjet ink composition M was prepared in the same manner as in Example 1 except that the amount was used.

Comparative Example 1
In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and isononyl acrylate “AIN” as a monofunctional monomer 46.7 parts (manufactured by Nippon Shokubai Co., Ltd.) and 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

In 25.0 parts of the dispersion thus obtained, 45.5 parts of “AIN” as a monofunctional monomer, 19.5 parts of “light acrylate DPE-6A” as a polyfunctional monomer, as a photopolymerization initiator Add 9.0 parts of “IRGACURE907” and 1.0 part of “DET-X”, and after stirring for 30 minutes with a magnetic stirrer, suction filtration is performed using a glass filter (manufactured by Kiriyama Seisakusho), and UV curable ink Composition N was prepared.

Comparative Example 2
In a 100 cc plastic bottle, 20.0 parts of “HOSTAPERM BLUE P-BFS” (manufactured by Clariant, copper phthalocyanine blue pigment), 33.3 parts of “DISPERBYK168” as a pigment dispersant, and “DMAA” 46.7 as an acrylamide derivative 100 parts of zirconia beads having a diameter of 0.3 mm were weighed and dispersed for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.).

In 25.0 parts of the dispersion thus obtained, 10.0 parts of “DMAA” as an acrylamide derivative, 55.0 parts of “light acrylate DPE-6A” as a polyfunctional monomer, “ Add 9.0 parts of IRGACURE907 ”and 1.0 part of“ DET-X ”, and stir for 30 minutes with a magnetic stirrer, and then suction filter using a glass filter (manufactured by Kiriyama Seisakusho) to form an ultraviolet curable ink composition. Article O was prepared.

Regarding the ultraviolet curable ink compositions A to M of Examples 1 to 13 and the ultraviolet curable ink compositions N and O of Comparative Examples 1 and 2, the compositions of the ink compositions are summarized in Tables 1 to 4. Showed. In addition, the code | symbol in Table 1-Table 4 is as follows.

"BYK-168": DISPERBYK168

"DMAA": Dimethylacrylamide

"ACMO": Acryloylmorpholine

"DEAA": Diethylacrylamide

“AIN”: isononyl acrylate

"DPE-6A": Light acrylate DPE-6A
(Dipentaerythritol hexaacrylate)

"PE-4A": Light acrylate PE-4A
(Pentaerythritol tetraacrylate)

“IRG.907”: IRGACURE907
{2-Methyl-1 [4- (methylthio) phenyl]
-2-morpholinopropan-1-one}

"DET-X": DET-X
(2,4-diethylthioxanthone)

“IRG.184”: IRGACURE184
(1-hydroxy-cyclohexyl-phenyl-ketone)

“IRG.819”: IRGACURE819
[Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide]

"BMS": KAYACURE BMS
{[4- (Methylphenylthio) phenyl] phenyl methanone}

"CTX": CTX
(2-chlorothioxanthone)

Table 1

┌───────────┬────┬────┬┬────┬────┐
│ │Example 1 │Example 2 │Example 3 │Example 4│
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Face (part) │ 5.0│ 5.0│ 5.0│ 5.0│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│ As pigment dispersant │ │ │ │ │
│Polymer Compound (Part) │ 8.3│11.7│ 6.7│ 6.7│
│ [BYK-168] │ │ │ │ │
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Acrylamide derivatives │ │ │ │ │
│ │ │ │ │ │
│ DMAA (part) | 57.2 | 53.8 | 58.8 | 58.8 |
│ │ │ │ │ │
│ ACMO (part) │-│-│-│-│
│ │ │ │ │ │
│ DEAA (part) │-│-│-│-│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Monofunctional monomer │ │ │ │ │
│ │ │ │ │ │
│ AIN (part) │ − │ − │ − │ − │
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Multifunctional monomer │ │ │ │ │
│ │ │ │ │ │
│ DPE-6A (part) │19.5│19.5│19.5│19.5│
│ │ │ │ │ │
│ PE-4A (Parts) │-│-│-│-│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Photopolymerization initiator │ │ │ │ │
│ │ │ │ │ │
│ IRG. 907 (parts) | 9.0 | 9.0 | 9.0 | 9.0 |
│ │ │ │ │ │
│ DET-X (Part) │ 1.0│ 1.0│ 1.0│ 1.0│
│ │ │ │ │ │
└───────────┴────┴────┴┴────┴────┘

Table 2

┌───────────┬────┬────┬┬────┬────┐
│ │Example 5 │Example 6 │Example 7 │Example 8│
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Face (part) │ 5.0│ 5.0│ 5.0│ 5.0│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│ As pigment dispersant │ │ │ │ │
│Polymer Compound (Parts) │ 8.3│ 8.3│ 8.3│ 8.3│
│ [BYK-168] │ │ │ │ │
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Acrylamide derivatives │ │ │ │ │
│ │ │ │ │ │
│ DMAA (part) │-│57.2│-│57.2│
│ │ │ │ │ │
│ ACMO (part) │57.2│-│-│-│
│ │ │ │ │ │
│ DEAA (part) │-│-│57.2 │-│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Monofunctional monomer │ │ │ │ │
│ │ │ │ │ │
│ AIN (part) │ − │ − │ − │ − │
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Multifunctional monomer │ │ │ │ │
│ │ │ │ │ │
│ DPE-6A (Part) │19.5│-│19.5│19.5│
│ │ │ │ │ │
│ PE-4A (Part) │-│19.5│-│-│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Photopolymerization initiator │ │ │ │ │
│ │ │ │ │ │
│ IRG. 907 (part) | 9.0 | 9.0 | 9.0 | 10.0 |
│ │ │ │ │ │
│ DET-X (Parts) │ 1.0│ 1.0│ 1.0│ − │
│ │ │ │ │ │
└───────────┴────┴────┴┴────┴────┘

Table 3

┌───────────┬────┬────┬┬────┬────┐
│ │Example 9│Example 10│Example 11│Example 12│
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Face (part) │ 5.0│ 5.0│ 5.0│ 5.0│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│ As pigment dispersant │ │ │ │ │
│Polymer Compound (Parts) │ 8.3│ 8.3│ 8.3│ 8.3│
│ [BYK-168] │ │ │ │ │
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Acrylamide derivatives │ │ │ │ │
│ │ │ │ │ │
│ DMAA (part) | 57.2 | 57.2 | 57.2 | 57.2 |
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Monofunctional monomer │ │ │ │ │
│ │ │ │ │ │
│ AIN (part) │ − │ − │ − │ − │
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Multifunctional monomer │ │ │ │ │
│ │ │ │ │ │
│ DPE-6A (part) │19.5│19.5│19.5│19.5│
│ │ │ │ │ │
├───────────┼────┼────┼┼────┼────┤
│ │ │ │ │ │
│Photopolymerization initiator │ │ │ │ │
│ │ │ │ │ │
│ IRG. 907 (parts) │-│ 5.0│-│-│
│ │ │ │ │ │
│ DET-X (Part) │ − │ − │ − │ − │
│ │ │ │ │ │
│ IRG. 184 (part) |--3.0---10.0 |
│ │ │ │ │ │
│ IRG. 819 (part) | 9.0 | − | 10.0 | − −
│ │ │ │ │ │
│ BMS (parts) │ 1.0│ 2.0│ − │ − │
│ │ │ │ │ │
└───────────┴────┴────┴┴────┴────┘

Table 4

┌───────────┬────┬────┬┬────┐
│ │Example 13│Comparative Example 1│Comparative Example 2│
├───────────┼────┼────┼┼────┤
│ │ │ │ │
│Face (part) │ 5.0│ 5.0│ 5.0│
│ │ │ │ │
├───────────┼────┼────┼┼────┤
│ │ │ │ │
│ As pigment dispersant │ │ │ │
│Polymer Compound (Parts) │ 8.3│ 8.3│ 8.3│
│ [BYK-168] │ │ │ │
│ │ │ │ │
├───────────┼────┼────┼┼────┤
│ │ │ │ │
│Acrylamide derivatives │ │ │ │
│ │ │ │ │
│ DMAA (part) │57.2│-│21.7│
│ │ │ │ │
│ ACMO (part) │ − │ − │ − │
│ │ │ │ │
├───────────┼────┼────┼┼────┤
│ │ │ │ │
│Monofunctional monomer │ │ │ │
│ │ │ │ │
│ AIN (part) │ − │57.2│ − │
│ │ │ │ │
├───────────┼────┼────┼┼────┤
│ │ │ │ │
│Multifunctional monomer │ │ │ │
│ │ │ │ │
│ DPE-6A (Parts) │19.5│19.5│55.0│
│ │ │ │ │
│ PE-4A (Part) │ − │ − │ − │
│ │ │ │ │
├───────────┼────┼────┼┼────┤
│ │ │ │ │
│Photopolymerization initiator │ │ │ │
│ │ │ │ │
│ IRG. 907 (parts) | 9.0 | 9.0 | 9.0 |
│ │ │ │ │
│ DET-X (part) │ − │ 1.0│ 1.0│
│ │ │ │ │
│ CTX (part) │ 1.0 │ − │ − │
│ │ │ │ │
└───────────┴────┴────┴┴────┘

Next, with respect to the ultraviolet curable ink compositions A to M of Examples 1 to 13 and the ultraviolet curable ink compositions N and O of Comparative Examples 1 and 2, their viscosities (mPa · s / 25 ° C.) and dispersion are used. The average particle diameter, surface tension, and storage stability under conditions of 70 ° C./7 days were measured by the following methods. These results are shown in Table 5.

<Viscosity>
Using an R100 viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity was measured under the conditions of 25 ° C. and cone rotation speed of 20 rpm.

<Dispersion average particle size>
The dispersion average particle diameter of the pigment particles was measured using a particle size distribution measuring device N4-PLUS (Laser Doppler type particle size distribution meter manufactured by Coulter, Inc.).

<Surface tension>
The surface tension was measured by setting the temperature of the ink composition to 25 ° C. using a fully automatic balance type electro surface tension meter ESB-V (manufactured by Kyowa Kagaku).

<Storage stability>
The ink composition was stored at a temperature of 70 ° C. for 7 days, the change in viscosity at this time was examined, and evaluated according to the following criteria.

○: Viscosity change is less than 10% ×: Viscosity change is 10% or more

Table 5

┌────┬───────┬───────┬──────┬─────┐
│ │ Viscosity [25 ° C] │ Dispersion average particle diameter │ Surface tension │ Storage stability │
│ │ (mPa · s) │ (nm) │ (mN / m) │ │
├────┼───────┼───────┼──────┼─────┤
│ │ │ │ │ │
│Example 1│ 6.7 │ 110.0 │ 36.8 │ ○ │
│ │ │ │ │ │
│Example 2│ 7.7 │ 150.0 │ 36.7 │ ○ │
│ │ │ │ │ │
│Example 3│ 5.2 │ 150.0 │ 36.7 │ ○ │
│ │ │ │ │ │
│Example 4│ 4.3 │ 105.0 │ 36.4 │ ○ │
│ │ │ │ │ │
│Example 5│ 9.5 │ 110.0 │ 38.5 │ ○ │
│ │ │ │ │ │
│Example 6│ 5.0 │ 110.0 │ 36.2 │ ○ │
│ │ │ │ │ │
│Example 7│ 5.0 │ 110.0 │ 36.5 │ ○ │
│ │ │ │ │ │
│Example 8│ 7.0 │ 110.0 │ 36.7 │ ○ │
│ │ │ │ │ │
│Example 9│ 6.8 │ 110.0 │ 36.7 │ ○ │
│ │ │ │ │ │
│Example 10│ 7.1 │ 110.0 │ 36.8 │ ○ │
│ │ │ │ │ │
│Example 11│ 7.5 │ 110.0 │ 36.5 │ ○ │
│ │ │ │ │ │
│Example 12│ 7.5 │ 110.0 │ 36.6 │ ○ │
│ │ │ │ │ │
│Example 13│ 6.6 │ 110.0 │ 36.7 │ ○ │
│ │ │ │ │ │
├────┼───────┼───────┼──────┼─────┤
│ │ │ │ │ │
│Comparative Example 1│ 10.0 │ 110.0 │ 29.0 │ ○ │
│ │ │ │ │ │
│Comparative Example 2│ 55.0 │ 110.0 │ 36.2 │ ○ │
│ │ │ │ │ │
└────┴───────┴───────┴──────┴─────┘

Next, with respect to the ultraviolet curable ink compositions A to M of Examples 1 to 13 and the ultraviolet curable ink compositions N and O of Comparative Examples 1 and 2, the continuous discharge property and curability of each ink composition and The substrate adhesion was measured by the following method. These results are shown in Table 6.

<Continuous discharge>
Recording was performed on a recording medium using an ink composition by an ink jet recording apparatus provided with a piezo ink jet nozzle, and evaluation was performed according to the following criteria.

The ink supply system is composed of an ink tank, a supply pipe, a front chamber ink tank immediately before the head, and a piezo head. The droplet size is about 7 pl, and 600 × 600 dpi (dpi is the number of dots per 2.54 cm). It was driven at a driving frequency of 10 KHz so that it could be ejected at a resolution of “say”.

○: No ejection failure at all for 30 minutes continuous emission Δ: No nozzle missing at 30 minutes continuous emission, but satellites generated ×: No nozzle missing at 30 minutes continuous emission

<Curing property>
The ink composition is printed on a recording medium comprising a polyvinyl chloride (PVC) or polyethylene terephthalate (PET) film by a bar coater (# 12) to form a 10 μm print film, and a metal halide lamp (120 W) Was used for curing so that the total irradiation light amount was 150 mJ / cm ² .

The printed matter cured in this manner was touched with a finger, the presence or absence of ink adhering to the finger was visually examined, and the following criteria were evaluated.

○: Does not adhere to fingers △: Does not adhere to fingers, but scratches on printed surface ×: Adheres to fingers

<Base material adhesion>
The ink composition is printed on a recording medium comprising a polyvinyl chloride (PVC) or polyethylene terephthalate (PET) film by a bar coater (# 12) to form a 10 μm print film, and a metal halide lamp (120 W) Was used for irradiation and curing so that the total irradiation light amount was 150 mJ / cm ² .

The printed matter thus cured was subjected to 100 cross-cuts test of 1 mm square according to JIS-K-5400, and the peeled state was confirmed with a cellophane tape. The adhesion number in 100 pieces (number of grids remaining without being peeled) was examined and evaluated according to the following criteria.

○: The number of peels in the cross cut test is 10 or less. Δ: The number of peels in the cross cut test is 20 or less. X: The number of peels in the cross cut test is 21 or more.

Table 6

┌────┬─────┬─────┬───────────┐
│ │Continuous discharge │ Curability │ Substrate adhesion │
│ │ │ ├─────┬─────┤
│ │ │ │ PVC │ PET │
├────┼─────┼─────┼─────┼┼─────┤
│ │ │ │ │ │
│Example 1│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 2│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 3│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 4│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 5│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 6│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 7│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
│Example 8│ ○ │ △ │ △ │ △ │
│ │ │ │ │ │
│Example 9│ ○ │ △ │ ○ │ ○ │
│ │ │ │ │ │
│Example 10│ ○ │ △ │ ○ │ ○ │
│ │ │ │ │ │
│Example 11│ ○ │ △ │ △ │ △ │
│ │ │ │ │ │
│Example 12│ ○ │ △ │ △ │ △ │
│ │ │ │ │ │
│Example 13│ ○ │ ○ │ ○ │ ○ │
│ │ │ │ │ │
├────┼─────┼─────┼─────┼┼─────┤
│ │ │ │ │ │
│Comparative Example 1│ ○ │ × │ − │ − │
│ │ │ │ │ │
│Comparative example 2│ × │ ○ │ − │ − │
│ │ │ │ │ │
└────┴─────┴─────┴─────┴┴─────┘

As is clear from the above results, each of the ultraviolet curable ink compositions A to M of Examples 1 to 13 employing the configuration of the present invention has suitability as an ink composition and has storage stability. Excellent, continuous ejection stability, curability and substrate adhesion are good, especially with regard to curability, the integrated light quantity can be cured quickly with low energy of 150 mJ / cm ² , and stable printing at room temperature by the inkjet recording method I understand that I can do it.

On the other hand, the ultraviolet curable ink compositions N and O of Comparative Examples 1 and 2 that do not take the configuration of the present invention are inferior in any of continuous discharge stability, curability, and substrate adhesion, and an inkjet recording method As a result, it was found that stable printing could not be performed at room temperature.

In addition, by an experiment different from the above, in the ultraviolet curable ink composition of the present invention, the amount of the trifunctional or higher polyfunctional monomer is reduced, or the bifunctional monomer ( For example, when “Light acrylate NP-A” manufactured by Kyoeisha Chemical Co., Ltd., neopentyl glycol diacrylate) was used, a tendency to be inferior in curability and continuous discharge stability was observed. From this result, it was also confirmed that it is desirable to use an appropriate amount of a trifunctional or higher polyfunctional monomer in the ultraviolet curable ink composition of the present invention.

Claims (12)

An energy ray curable ink composition containing a coloring material, a monomer, and a photopolymerization initiator, comprising an acrylamide derivative as a monomer, and the amount of the acrylamide derivative is 10 to 90% by weight in the whole ink composition An energy ray-curable ink composition, wherein the viscosity of the entire ink composition is 3 to 35 mPa · s at 25 ° C.

The energy ray-curable ink composition according to claim 1, wherein the viscosity of the entire ink composition is 3 to 20 mPa · s at 25 ° C.

The energy ray curable ink composition according to claim 1 or 2, comprising a trifunctional or higher polyfunctional acrylate monomer as a monomer, and the amount of the polyfunctional acrylate monomer is 10 to 50% by weight in the entire ink composition. object.

The energy ray curable ink composition according to any one of claims 1 to 3, wherein the photopolymerization initiator comprises two or more kinds.

5. The photopolymerization initiator according to claim 4, comprising at least 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one and a compound selected from thioxanthones. Energy ray curable ink composition.

The energy ray curable ink composition according to any one of claims 1 to 5, wherein the amount of the photopolymerization initiator is 1 to 20% by weight in the whole ink composition.

The energy ray curable ink composition according to any one of claims 1 to 6, wherein the colorant is an organic pigment and / or an inorganic pigment.

The energy ray-curable ink composition according to claim 7, wherein the amount of the organic pigment and / or inorganic pigment is 1 to 10% by weight based on the whole ink composition.

The energy ray-curable ink composition according to claim 7 or 8, which contains a polymer compound as a pigment dispersant.

The energy ray-curable ink composition according to claim 9, wherein the amount of the polymer compound is 5 to 150% by weight based on the organic pigment and / or the inorganic pigment.

The energy ray-curable ink composition according to any one of claims 1 to 10, which is cured at an integrated light amount of 150 mJ / cm ² or less.

The energy ray curable ink composition according to claim 1, which is used in an ink jet recording system.