JP4918986B2 - Pigment dispersion and method for producing the same, photocurable ink composition using the pigment dispersion, recording method using the photocurable ink composition, and recorded matter by the recording method - Google Patents

Description

  The present invention relates to a pigment dispersion, a method for producing the same, and a photocurable ink composition using the pigment dispersion, and in particular, during the dispersion treatment without using a polymerization inhibitor and an organic solvent that does not cause a polymerization reaction. The present invention relates to a pigment dispersion in which no monomer undergoes a polymerization reaction, a method for producing the same, and a photocurable ink composition containing the pigment dispersion.

  When preparing a pigment ink composition for inkjet, it is common to disperse the pigment using a dispersing device and to disperse it stably in the ink composition. In the photocurable pigment ink composition, a polymerizable compound called a monomer is used as an ink solvent, but this is very difficult to disperse together with the pigment. The reason is that the monomer initiates a polymerization reaction due to heat generated during the dispersion process or radicals generated mechanochemically, causing an undesirable phenomenon such as increase in viscosity or gelation.

In order to improve this inconvenience, there is a technique of adding a polymerization inhibitor to suppress the polymerization reaction of the monomer. For example, an ink composition containing 100 to 10,000 ppm of a polymerization inhibitor improves ink storage stability, bleeding resistance, stability after printing (such as abrasion resistance), and smoothness, and a recording medium It is disclosed that a good image can be obtained regardless of the type of the recording medium (particularly a recording medium having no ink absorbability) and a stable high-definition image can be printed (Patent Document 1). ). As another example, (a) a pigment dispersion containing 20 to 95% by mass of pigment, (b) a polymerizable compound, (c) a polymerization initiator, and further containing a polymerization inhibitor. The actinic ray curable ink having a viscosity at 25 ° C. of 6 to 500 mPa · s and a water content measured by the Karl Fischer method of 0.01 to 2.5% by mass has low viscosity, sensitivity, and emission stability. In addition, it is disclosed that it is excellent in heat cycle property and ink storage stability (Patent Document 2).
JP 2003-127518 A JP 2003-306622 A

  However, the above-described conventional technology has a problem in that a polymerization inhibitor is inevitably mixed in the photocurable pigment ink composition, thereby inhibiting the curing reaction of the photocurable pigment ink composition. Therefore, in the photocurable pigment ink composition, a dispersion treatment is performed using an organic solvent that does not cause a polymerization reaction, and then a monomer or a photopolymerization initiator is added to the ink using a solvent dispersion of the obtained pigment. It is common to prepare compositions.

  However, in this method, since an organic solvent unnecessary for the curing reaction is present in the ink, a drying step before the curing reaction is essential in order to remove the organic solvent. Also, volatilization of the organic solvent in the air is not preferable from the viewpoint of the work environment, the burden on equipment such as the local exhaust device and the exhaust gas combustion device, and the influence on the surrounding environment. In addition, a method of substituting an organic solvent with a monomer, for example, a method using a difference in boiling point in an evaporator or a distillation operation can be considered, but the manufacturing process of the ink composition increases, the cost increases, and the organic solvent is completely removed. There was a problem that it was difficult to do.

  Therefore, the present invention includes a pigment dispersion in which a monomer does not undergo a polymerization reaction during the dispersion treatment without using a polymerization inhibitor and an organic solvent that does not cause a polymerization reaction, a method for producing the same, and the pigment dispersion. An object is to provide a photocurable ink composition.

In order to solve the above-mentioned problems, the present invention is a pigment dispersion containing at least a colorant, a dispersant, and a polymerizable compound, and substantially free of a polymerization inhibitor, , Ri Oh polyoxyalkylene polyalkylene amine, wherein the polymerizable compound is to provide a pigment dispersion, which is a N- vinyl formamide or ethylene glycol monoallyl ether. Thereby, even if it does not use the polymerization inhibitor and the organic solvent which does not raise | generate a polymerization reaction, a pigment dispersion liquid can be prepared, without a polymeric compound (monomer) carrying out a polymerization reaction during a dispersion process.

  Preferred embodiments of the invention are as follows. The polymerizable compound is preferably N-vinylformamide or ethylene glycol monoallyl ether. These polymerizable compounds copolymerize with other monomers, but do not undergo a polymerization reaction alone. Therefore, by using only the above compound as the polymerizable compound, it is possible to disperse the pigment monomer without using a polymerization inhibitor.

In order to solve the above problems, the present invention mixes at least a mixture containing a colorant, a dispersant, and a polymerizable compound, and the mixture is substantially free of a polymerization inhibitor. distributed processing to a method of producing a pigment dispersion, a dispersant, have use a polyoxyalkylene polyalkylene amine, as the polymerizable compound, the use of N- vinylformamide or ethylene glycol monoallyl ether A method for producing a pigment dispersion characterized by the above is provided. Thereby, even if it does not use the polymerization inhibitor and the organic solvent which does not raise | generate a polymerization reaction, a pigment dispersion liquid can be prepared, without a polymeric compound (monomer) carrying out a polymerization reaction during a dispersion process.

  Preferred embodiments of the invention are as follows. As the polymerizable compound, N-vinylformamide or ethylene glycol monoallyl ether is preferably used. These polymerizable compounds do not undergo a polymerization reaction alone, but copolymerize with other monomers. Therefore, by using only the above compound as the polymerizable compound and dispersing the pigment, it is possible to disperse the pigment monomer without using a polymerization inhibitor.

  The present invention also provides a photocurable ink composition containing the pigment dispersion, a photopolymerization initiator, and a polymerizable compound. Since the photocurable ink composition of the present invention does not substantially contain a polymerization inhibitor, it can form an image of excellent quality without inhibiting the curing reaction of the photocurable ink composition. .

  Further, the present invention is a recording method for printing on a recording medium with an ink composition attached thereto, wherein the photocurable ink composition is used as the ink composition and then irradiated with ultraviolet rays. A recording method for curing a photocurable ink composition is provided. Since the recording method of the present invention uses the photocurable ink composition, an image of excellent quality can be formed without inhibiting the curing reaction of the photocurable ink composition. Further, since the pigment dispersion does not contain an organic solvent, there is no need for a drying process, and no exhaust treatment facility is required, which is advantageous in terms of cost and can improve the influence on the working environment and the surrounding environment.

  An ink jet recording method for performing printing by ejecting droplets of an ink composition and attaching the droplets to a recording medium, wherein the photocurable ink composition is used as the ink composition and then irradiated with ultraviolet rays. Thus, a recording method for curing the photocurable ink composition is provided. Since the recording method of the present invention uses the photocurable ink composition, an image of excellent quality can be formed without inhibiting the curing reaction of the photocurable ink composition. Further, since the pigment dispersion does not contain an organic solvent, there is no need for a drying process, and no exhaust treatment facility is required, which is advantageous in terms of cost and can improve the influence on the working environment and the surrounding environment.

  The present invention also provides a recorded matter printed by the recording method. In the present invention, since printing is performed by a recording method using the photocurable ink composition, an image of excellent quality can be formed.

  According to the pigment dispersion and the method for producing a pigment dispersion of the present invention, the polymerizable compound (monomer) undergoes a polymerization reaction during the dispersion treatment without using a polymerization inhibitor and an organic solvent that does not cause a polymerization reaction. Therefore, a high-quality photocurable ink composition can be obtained without being affected by the polymerization inhibitor in the photocurable ink composition. Moreover, since it is not necessary to use an organic solvent, it is not necessary to carry out the removal process of the organic solvent, which has been conventionally required, and the manufacturing process and cost burden can be reduced.

  In addition, according to the photocurable ink composition of the present invention, since the polymerization inhibitor of the pigment dispersion is substantially not included, the curing reaction of the photocurable ink composition is not hindered and is excellent. A quality image can be formed.

  Further, according to the recording method and recorded matter of the present invention, since the photocurable ink composition is used, an image of excellent quality is formed without inhibiting the curing reaction of the photocurable ink composition. be able to.

[Pigment dispersion]
As described above, the pigment dispersion of the present invention is a pigment dispersion containing at least a colorant, a dispersant, and a polymerizable compound, and substantially free of a polymerization inhibitor. Is a polyoxyalkylene polyalkyleneamine.

Polyoxyalkylenepolyalkylenepolyamine _{(C 2 H 4 N) n} - (PO) x - (EO) in _y -OH (the above formulas, n, x and y means an integer of 1 or more, respectively, PO is propylene Specific examples of EO means ethylene oxide.) For example, Discole N-503, N-506, N-509, N-512, N-515, N-518 , N-520 and the like.

  The amount of the dispersant added is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

Here, the pigment dispersion according to the present invention does not substantially contain a polymerization inhibitor. By "polymer substantially free of inhibitor", the content of the pigment dispersion, even if it contains a polymerization inhibitor in raw materials due refers to less than 0.01 wt%. This is because if a photocurable pigment ink composition is prepared using a pigment dispersion containing 0.01% by weight or more of a polymerization inhibitor, the curing reaction of the photocurable pigment ink composition may be inhibited. . The “polymerization inhibitor” means a compound blended in a general polymerizable composition. Specifically, for example, a phenol-based antioxidant, a hindered amine light stabilizer, a phosphorus-based oxidation agent, and the like. In addition to the inhibitor, hydroquinone monomethyl ether widely used for (meth) acrylic monomers, hydroquinone, t-butylcatechol, pyrogallol and the like can be mentioned.

  The polymerizable compound used in the pigment dispersion according to this embodiment is preferably N-vinylformamide or ethylene glycol monoallyl ether (trade name allyl glycol). These polymerizable compounds copolymerize with other monomers, but do not undergo a polymerization reaction alone. Therefore, using this characteristic, the pigment is dispersed using only the above compound as the polymerizable compound. This prevents a polymerization reaction from occurring during the dispersion treatment and increasing the viscosity of the dispersion. As a result, it is possible to disperse the pigment monomer without using a polymerization inhibitor.

  The colorant used in the present embodiment is preferably a pigment from the viewpoint of light resistance. As the pigment, both inorganic pigments and organic pigments can be used.

  As inorganic pigments, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, iron oxide, titanium oxide, and the like can be used.

  Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments Polycyclic pigments, dye chelates (for example, basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daytime Examples thereof include photofluorescent pigments. The above pigments can be used alone or in combination of two or more. Further, any pigment that is not described in the color index can be used as long as it is insoluble in the ink composition.

  As the black pigment, carbon black is preferable. Specific examples of carbon black include # 2300, # 900, HCF88, # 33, # 40, # 45, # 52, MA7, MA8, MA100, # 2200B manufactured by Mitsubishi Chemical, Raven 5750, 5250 , 5000, 3500, 1255, 700, etc., Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, 900, 1000, 1100, 1300, manufactured by Cabot Corporation , 1400, etc. Color Black FW1, FW2V, FW18, FW200, Color Black S150, S160, S170, Printex 35, U, V, 140U, Special Black 6, 5 4A, same Etc. can be mentioned, may be used as these one or a mixture of.

  Examples of yellow pigments 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, etc., preferably C.I. I. 1 or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128 and 138.

  Examples of magenta and light magenta pigments include C.I. I. Pigment Red, 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 15: 1, 112, 122, 123, 168, 184, 202, 209 and C.I. I. Pigment violet 19 and the like, preferably C.I. I, Pigment Red 122, 202, 209 and C.I. I. One or a mixture of two or more selected from the group consisting of CI Pigment Violet 19.

  Examples of cyan and light cyan pigments include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60 and C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and one or a mixture of two or more selected from the group consisting of 60.

  As pigments used in white ink, titanium dioxide, calcium carbonate, calcium sulfate, zinc oxide, barium sulfate, barium carbonate, silica, alumina, kaolin, clay, talc, clay, aluminum hydroxide, magnesium carbonate, white hollow resin emulsion Preferably, it is one or a mixture of two or more selected from the group consisting of these.

  In addition, the pigments of the respective colors can be mixed and used in order to adjust the color tone. For example, pigment black 7 and pigment blue 15: 3 can be mixed for the purpose of changing the color tone of reddish black to blue.

  The pigment used in this embodiment preferably has an average particle diameter in the range of 10 to 500 nm, more preferably about 50 to 300 nm. Further, the blending amount of the pigment used in the present embodiment may be appropriately determined according to the type of the ink composition such as the dark and light ink composition, but is preferably 1.5 to 20% by weight in the ink composition. Is 3 to 10% by weight.

[Method for producing pigment dispersion]
As described above, the method for producing a pigment dispersion of the present invention comprises mixing a mixture containing at least a colorant, a dispersant, and a polymerizable compound, in a state substantially free of a polymerization inhibitor. A method for producing a pigment dispersion by dispersing a mixture, wherein a polyoxyalkylene polyalkyleneamine is used as the dispersant.

  The polymerizable compound used in the pigment dispersion according to this embodiment is preferably N-vinylformamide or ethylene glycol monoallyl ether. These polymerizable compounds copolymerize with other monomers, but do not undergo a polymerization reaction alone. Therefore, by dispersing the pigment using only the above compound as the polymerizable compound, it is possible to disperse the pigment monomer without using a polymerization inhibitor.

  For the dispersion treatment, a usual dispersion method used in preparing a pigment dispersion can be used. For example, at least a colorant, a dispersant, and a polymerizable compound are mixed and stirred to form a mixture, and using a sand mill, with a zirconia bead having a diameter of 1.0 to 3.0 mm, under a dispersion temperature of 40 ° C. or less. By stirring at high speed for 3 to 12 hours, a pigment dispersion in which the pigment is dispersed in a solvent can be prepared. The zirconia beads are then separated from the pigment dispersion.

  Note that the matters described for the “pigment dispersion” are appropriately applied to matters not specifically described in the present embodiment.

[Photocurable ink composition]
The photocurable ink composition of the present invention contains the above-described pigment dispersion, a photopolymerization initiator, and a polymerizable compound.

  Examples of the photopolymerization initiator include known photopolymerization initiators described in pages 39 to 56 of Photopolymer Handbook (published by Photographic Society Association, 1989), Japanese Patent Laid-Open No. 64-13142, Japanese Patent Laid-Open No. The compounds described in 4804 can be used arbitrarily.

  The polymerizable compound is not particularly limited, and various polymerizable compounds can be used, but N-vinylformamide or ethylene glycol monoallyl ether (trade name allyl glycol) is preferably used.

  The polymerizable compound other than the N-vinylformamide and ethylene glycol monoallyl ether is not particularly limited as long as it is polymerized by radicals or ions generated from a photopolymerization initiator. Such a polymerizable compound refers to a molecule that can be a structural unit of a basic structure of a polymer. Such a polymerizable compound is also called a photopolymerizable monomer, and includes a monofunctional monomer, a bifunctional monomer, and a polyfunctional monomer. The monofunctional monomer, bifunctional monomer, and polyfunctional monomer are not particularly limited, and those having a molecular weight of about 100 to 3000 (preferably about 100 to 2000) can be used.

  Representative examples of such polymerizable compounds include monofunctional monomers such as phenoxyethyl acrylate, isobornyl acrylate, methoxydiethylene glycol monoacrylate, acroylmorpholine, lauryl methacrylate, 2-hydroxyethyl methacrylate, and methacrylic acid. Examples include cyclohexyl and oxetane methacrylate.

  Bifunctional monomers include ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, polyethylene glycol # 400 diacrylate, tetraethylene glycol dimethacrylate 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, hydroxypioperic acid ester neo Examples include pentyne glycol diacrylate and 1,4-butanediol dimethacrylate.

  Multifunctional monomers include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane EO adduct triacrylate, trimethylolpropane PO adduct triacrylate, glycerin EO adduct triacrylate, glycerin PO adduct triacrylate , Pentaerythritol triacrylate, dipentaerythrole hexaacrylate, dipentaerythritol polyacrylate, dendrimers prepared by utilizing a reaction between polyfunctional monomers, and the like.

  In addition, other polymerization accelerators can be added to the photocurable ink composition of the present embodiment. Examples of the other polymerization accelerators include polymerization accelerators composed of amine compounds. The amine compound is not particularly limited, but an aminobenzoate derivative is particularly preferable because the problem of odor and the curing of the ink composition become more reliable. This is because the aminobenzoate derivative reduces polymerization inhibition by oxygen.

  The aminobenzoate derivative preferably has no absorption in the wavelength region of 350 nm or more. Examples of such aminobenzoate derivatives include, but are not limited to, ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, etc., which include Darocur EDB, EHA (Ciba Specialty Chemicals) Product name).

  As a photopolymerization initiator contained in the photocurable ink composition of the present embodiment, for example, ultraviolet rays or visible light in a region of about 200 nm to 450 nm is absorbed to generate radicals or ions to start polymerization of the polymerizable compound. It is something to be made.

  Typical photopolymerization initiators used in the photocurable ink composition of the present embodiment include radical generating types such as benzoin methyl ether, benzoin ethyl ether, isopropyl benzoin ether, isobutyl benzoin ether, 1-phenyl. -1,2-propanedione-2- (o-ethoxycarbonyl) oxime, benzyl, diethoxyacetophenone, benzophenone, chlorothioxanthone, 2-chlorothioxanthone, isopropylthioxanthone, 2-methylthioxanthone, polychlorinated polyphenyl, hexachlorobenzene, etc. Preferably, it is isobutyl benzoin ether, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime.

  Also, Vicure 10, 30 (manufactured by Stauffer Chemical), Irgacure 184, 127, 500, 651, 2959, 907, 369, 379, 754, 1700, 1800, 1850, 1870, 819, OXE01, Darocur 1173, TPO, ITX (Manufactured by Ciba Specialty Chemicals), Quanture CTX, ITX (manufactured by Aceto Chemical), Kayacure DETX-S (manufactured by Nippon Kayaku), ESACURE KIP150 (manufactured by Lamberti), Lucirin TPO (manufactured by BASF) Available photopolymerization initiators can also be used.

  The photocurable ink composition of the present embodiment may contain an aqueous solvent. Furthermore, resin emulsions, inorganic oxide colloids, wetting agents, pH adjusters, preservatives, fungicides, thermal polymerization inhibitors, surfactants and the like may be added as optional components.

[Recording method]
The recording method in the present embodiment is a recording method using the above-described photocurable ink composition. The recording method using the photocurable ink composition is, for example, an ink jet recording method, a recording method using a writing instrument such as a pen, and the like, and the photocurable ink composition is attached by various printing methods, and then irradiated with ultraviolet rays. It is hardened by doing. Therefore, the photocurable ink composition according to the embodiment can be preferably used for applications such as writing instruments such as an aqueous pen, an ink jet recording method, printing, and a stamp.

  According to another aspect of the recording method of the present embodiment, there is provided an ink jet recording method in which droplets of the ink composition of the above-described embodiment are ejected and adhered to a recording medium, and then cured by irradiation with ultraviolet rays. The As the ink jet recording method according to the present embodiment, any method can be used as long as the ink composition is ejected as droplets from a fine nozzle and the droplets are attached to a recording medium. As specific examples of such a method, methods of various modes are known.

  An example of such a method is an electrostatic suction method. In this method, a strong electric field is applied between the nozzle and the acceleration electrode placed in front of the nozzle, the ink composition is continuously ejected from the nozzle in the form of droplets, and the ink droplets fly between the deflection electrodes. A print information signal is applied to the deflection electrode and recorded. In this method, if necessary, ink droplets may be ejected in response to a print information signal without being deflected.

  As another aspect, there is a method of forcibly ejecting ink droplets by applying pressure to the ink liquid with a small pump and mechanically vibrating the nozzle with a crystal resonator or the like. In this method, the ejected ink droplet is charged simultaneously with the ejection, and a printing information signal is applied to the deflection electrode and recorded while the ink droplet flies between the deflection electrodes. Another embodiment includes a method using a piezoelectric element. In this method, pressure and a print information signal are simultaneously applied to ink liquid by a piezoelectric element, and ink droplets are ejected to perform recording. As yet another aspect, there is a method in which the volume of ink is rapidly expanded by the action of thermal energy. In this method, ink is heated and foamed with a microelectrode in accordance with a print information signal, and ink droplets are ejected to perform recording.

  The recording medium is not particularly limited, and various recording media such as plain paper, inkjet dedicated paper (matte paper, glossy paper), glass, plastic, film, metal, and printed wiring board can be used.

It is preferable to select a preferable condition for the irradiation amount of the ultraviolet ray according to the amount and thickness of the ink composition deposited on the substrate or the recording medium. Therefore, strictly speaking can not be specified, for example, 10 mJ / cm ² or more, 10,000 / cm ² or less, and preferably 50 mJ / cm ² or more, is preferably performed at 6,000 mJ / cm ² or less in the range . 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.

  From the viewpoint of reducing energy consumption, it is particularly preferable to irradiate ultraviolet rays with an ultraviolet light emitting semiconductor element such as an ultraviolet light emitting diode (ultraviolet LED) or an ultraviolet light emitting semiconductor laser.

  In the recording method using the ink composition of the present embodiment, heating may be performed before, at the same time as, or after irradiation with ultraviolet light. Heating is performed without bringing the recording medium into contact with the recording medium, such as heating by bringing a heat source into contact with the recording medium, irradiating infrared rays or microwaves (electromagnetic waves having a maximum wavelength of about 2,450 MHz), or blowing hot air. The method etc. are mentioned.

[Recordings]
Furthermore, according to the present embodiment, a recorded matter recorded by the recording method according to the embodiment is also provided. This recorded matter was recorded by discharging at least the droplets of the above-described photocurable ink composition and attaching the droplets to a recording medium. Since the recorded matter recorded by the recording method according to the embodiment is recorded using the above-described photocurable ink composition, it is excellent in quick-drying and durability. As a specific example of the recording medium, the recording medium described above can be used.

1. Preparation of pigment dispersion [Pigment dispersion 1] Example 1
As a coloring agent, C.I. I. 15 parts of Pigment Black 7 (carbon black), 3.5 parts of Discol N-518 (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a dispersant, and N-vinylformamide (manufactured by Arakawa Chemical Industries, Ltd.) as a monomer. In addition, the whole was made up to 100 parts and mixed and stirred to obtain a mixture. This was subjected to a dispersion treatment for 6 hours together with zirconia beads (diameter 1.5 mm) using a sand mill (manufactured by Yaskawa Seisakusho). Thereafter, the zirconia beads were separated with a separator to obtain Pigment Dispersion Liquid 1 (Example 1). In addition, it was 10.1 (mPa * s) when the initial viscosity of the pigment dispersion liquid 1 was measured using Physica MCR-300.

[Pigment dispersion 2] Example 2
The colorant is C.I. I. Pigment Yellow 155 and Discol N-518 were prepared in the same manner as Pigment Dispersion Liquid 1 except that 1.0 part was added, and Pigment Dispersion Liquid 2 (Example 2) was obtained. In addition, it was 6.4 (mPa * s) when the initial viscosity of the pigment dispersion liquid 2 was measured using Physica MCR-300.

[Pigment dispersion 3] Example 3
The colorant is C.I. I. A pigment dispersion 3 (Example 3) was obtained in the same manner as in Pigment Dispersion Liquid 1 except that the amount of Pigment Violet 19 and Discol N-518 added was 1.0 part. In addition, it was 7.4 (mPa * s) when the initial viscosity of the pigment dispersion liquid 3 was measured using Physica MCR-300.

[Pigment dispersion 4] Example 4
The colorant is C.I. I. Pigment Blue 15 (3) and Discol N-518 were added in the same manner as in Pigment Dispersion Liquid 1 except that the amount added was 2.0 parts to obtain Pigment Dispersion Liquid 4 (Example 4). In addition, it was 5.9 (mPa * s) when the initial viscosity of the pigment dispersion liquid 4 was measured using Physica MCR-300.

[Pigment dispersion 5] Example 5
C. as a colorant I. 15 parts of Pigment Black 7 (carbon black), 3.5 parts of Discol N-509 (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a dispersing agent, allyl glycol (trade name, manufactured by Nippon Emulsifier Co., Ltd.) as a polymerizable compound (Hereinafter referred to as “AG”) to make 100 parts as a whole, mix and stir to make a mixture, and use a sand mill (manufactured by Yaskawa Seisakusho) to disperse with zirconia beads (diameter 1.5 mm) for 6 hours Went. Thereafter, zirconia beads were separated with a separator to obtain Pigment Dispersion Liquid 5 (Example 5). In addition, it was 8.8 (mPa * s) when the initial viscosity of the pigment dispersion liquid 5 was measured using Physica MCR-300.

[Pigment dispersion 6] Example 6
The colorant is C.I. I. A pigment dispersion 6 (Example 6) was obtained in the same manner as in the pigment dispersion 5 except that the pigment yellow 155 was used. In addition, it was 7.6 (mPa * s) when the initial viscosity of the pigment dispersion liquid 6 was measured using Physica MCR-300.

[Pigment dispersion 7] Example 7
The colorant is C.I. I. A pigment dispersion 7 (Example 7) was obtained in the same manner as in Pigment Dispersion 5 except that Pigment Violet 19 was used. In addition, it was 6.2 (mPa * s) when the initial viscosity of the pigment dispersion liquid 6 was measured using Physica MCR-300.

[Pigment dispersion 8] Example 8
The colorant is C.I. I. A pigment dispersion 8 (Example 8) was obtained in the same manner as in the pigment dispersion 5 except that Pigment Blue 15: 3 was used. In addition, it was 7.2 (mPa * s) when the initial viscosity of the pigment dispersion liquid 8 was measured using Physica MCR-300.

[Pigment dispersion 9] Comparative Example 1
C. as a colorant I. Add 15 parts of Pigment Black 7 (carbon black), 3.5 parts of styrene-acrylic acid copolymer / ammonium salt (average molecular weight 10,000) as a dispersant to 100 parts, mix and stir. Using a sand mill (manufactured by Yaskawa Seisakusho Co., Ltd.) as a mixture, dispersion treatment was performed with zirconia beads (diameter 1.5 mm). However, the obtained pigment dispersion 9 (Comparative Example 1) gelled within 1 hour from the start of dispersion, and the beads could not be separated. Therefore, the initial viscosity of the pigment dispersion 9 could not be measured.

[Pigment dispersion 10] Comparative example 2
C. as a colorant I. Add AG to 15 parts of Pigment Black 7 (Carbon Black), 3.5 parts of Discol N-509 as a dispersant, and 0.2 parts of p-methoxyphenol (manufactured by Kanto Chemical Co., Ltd.) as a thermal polymerization inhibitor. The total was 100 parts, and the mixture was stirred to obtain a mixture. This was subjected to a dispersion treatment for 6 hours together with zirconia beads (diameter 1.5 mm) using a sand mill (manufactured by Yaskawa Seisakusho). Thereafter, the zirconia beads were separated with a separator to obtain pigment dispersion 10 (Comparative Example 2). In addition, it was 8.8 (mPa * s) when the initial viscosity of the pigment dispersion liquid 8 was measured using Physica MCR-300.

[Pigment Dispersion 11] Comparative Example 3
The colorant is C.I. I. A pigment dispersion 11 (Comparative Example 3) was obtained in the same manner as Pigment Dispersion 10 except that Pigment Yellow 155 was used. In addition, it was 7.6 (mPa * s) when the initial viscosity of the pigment dispersion liquid 11 was measured using Physica MCR-300.

[Pigment dispersion 12] Comparative example 4
The colorant is C.I. I. A pigment dispersion 12 (Comparative Example 4) was obtained in the same manner as in Pigment Dispersion 10 except that Pigment Violet 19 was used. In addition, it was 6.4 (mPa * s) when the initial viscosity of the pigment dispersion liquid 12 was measured using Physica MCR-300.

[Pigment dispersion 13] Comparative Example 5
The colorant is C.I. I. A pigment dispersion 13 (Comparative Example 5) was obtained in the same manner as Pigment Dispersion 10 except that Pigment Blue 15: 3 was used. In addition, it was 7.3 (mPa * s) when the initial viscosity of the pigment dispersion liquid 13 was measured using Physica MCR-300.

[Pigment dispersion 14] Comparative Example 6
C. as a colorant I. 15 parts of Pigment Black 7 (carbon black), 3.5 parts of styrene-acrylic acid copolymer / ammonium salt (average molecular weight 10,000) as a dispersant, 0.2 parts of p-methoxyphenol as a thermal polymerization inhibitor Then, AG as a monomer was added to make 100 parts as a whole, and mixed and stirred to obtain a mixture. This was subjected to a dispersion treatment for 2 hours together with zirconia beads (diameter 1.5 mm) using a sand mill (manufactured by Yasukawa Seisakusho). Thereafter, the zirconia beads were separated by a separator to obtain a pigment dispersion 14 (Comparative Example 6). In addition, it was 35.2 (mPa * s) when the initial viscosity of the pigment dispersion liquid 14 was measured using Physica MCR-300.

[Pigment dispersion 15] Comparative example 7
C. as a colorant I. Pigment Black 7 (carbon black) 15 parts, Discol N-509 3.5 parts as a dispersant, 0.2 parts p-methoxyphenol as a thermal polymerization inhibitor, and NVF as a monomer are added to make 100 The mixture was mixed and stirred to obtain a mixture. This was subjected to a dispersion treatment for 6 hours together with zirconia beads (diameter 1.5 mm) using a sand mill (manufactured by Yaskawa Seisakusho). Thereafter, the zirconia beads were separated by a separator to obtain a pigment dispersion 15 (Comparative Example 7). In addition, it was 11.3 (mPa * s) when the initial viscosity of the pigment dispersion liquid 15 was measured using Physica MCR-300.

2. Preparation of Photocurable Ink Composition Using the pigment dispersion liquid 1 prepared as described above, a photocurable ink composition 1 was prepared with the following composition. That is, APG-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.), Biscoat # 360 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) and AG (manufactured by Nippon Emulsifier Co., Ltd.) were used as monomers. The additives used were Irgacure 819 and 369 and Darocur EHA (both manufactured by Ciba Specialty Chemicals) as photopolymerization initiators, and BYK-UV3570 (manufactured by Big Chemie Japan) as surfactants. These were mixed and completely dissolved to prepare an ink solvent. Next, the pigment dispersion 1 was gradually dropped into the ink solvent while stirring. After completion of dropping, the mixture was stirred for 1 hour at room temperature. Then, it filtered with a 5-micrometer membrane filter, and was set as the desired photocurable ink composition 1 (Example 9).

Pigment dispersion 20% by weight
APG-200 20% by weight
Biscote # 360 15% by weight
Irgacure 819 4% by weight
Irgacure 369 1% by weight
Darocur EHA 1% by weight
BYK-UV3570 0.5% by weight
AG remaining amount

  Subsequently, the pigment type was changed, and photocurable ink compositions 2 to 12 (Examples 9 to 16 and Comparative Examples 8 to 11) were prepared in the same manner as in the case of the photocurable ink composition 1. Note that the dispersion 9 (Comparative Example 1), the dispersion 14 (Comparative Example 6), and the dispersion 15 (Comparative Example 7) had abnormally increased viscosity due to the dispersion treatment, and thus these are the photocurable ink compositions. It was not used as a raw material.

[Test Example 1] Evaluation of storage stability The pigment dispersions 1 to 15 (Examples 1 to 8 and Comparative Examples 1 to 7) were put in a light-shielding storage container and heated in an environment of 60 ° C for 5 days. The viscosity change (Δη) after 5 days from the initial viscosity was measured. The measurement of the viscosity was performed using MCR-300 manufactured by Physica. From the measured values, the storage stability of the pigment dispersion was evaluated using the following evaluation criteria. The results are shown in Table 1.
A: Viscosity change (Δη) after 5 days is ± 0.2 (mPa · s) or less.
B: Change in viscosity (Δη) after 5 days exceeds ± 0.2 (mPa · s).

[Test Example 2] Curability Evaluation Samples obtained by dropping the photocurable ink compositions 1 to 12 (Examples 9 to 16 and Comparative Examples 8 to 11) prepared as described above onto a glass substrate were as follows. The curability of the photocurable ink composition was evaluated in the same manner. As the ultraviolet irradiation device, an ultraviolet light emitting diode NICHIA i-LED “NCCU033” having a peak wavelength of 365 nm and an ultraviolet light emitting diode NICHIA “NCCU001” having a peak wavelength of 380 nm (both manufactured by Nichia Corporation) were used. Irradiation conditions of the ultraviolet irradiation apparatus, the irradiation surface, the irradiation intensity of the wavelength of 365nm and 380nm is set to be 40 mW / cm ^2, respectively 20 mW / cm ^2, i.e. in total. Then, the sample is irradiated with ultraviolet rays for 5 seconds to give an integrated light amount of 200 mJ / cm ² (in the table, expressed as “curability 1”), and irradiated for 15 seconds to give an integrated light amount of 600 mJ / cm ^2. The test was performed in two separate conditions (denoted as “curability 2” in the table). Then, the curability of the photocurable ink composition (simply referred to as “ink” in the table) was evaluated using the following evaluation criteria. The results are shown in Table 2 together with the addition amount (% by weight) of the thermal polymerization inhibitor.
A: Cured without problems.
B: Hardening failure occurs.

Claims (6)

A pigment dispersion containing at least a colorant, a dispersant, and a polymerizable compound, and substantially free of a polymerization inhibitor ,
The dispersant, Ri Oh polyoxyalkylene polyalkylene amine,
A pigment dispersion, wherein the polymerizable compound is N-vinylformamide or ethylene glycol monoallyl ether . Mixing a mixture containing at least a colorant, a dispersant, and a polymerizable compound;
A method for producing a pigment dispersion by dispersing the mixture in a state substantially free of a polymerization inhibitor ,
As dispersant, you have use a polyoxyalkylene polyalkylene amine,
A method for producing a pigment dispersion , wherein N-vinylformamide or ethylene glycol monoallyl ether is used as the polymerizable compound . A photocurable ink composition comprising the pigment dispersion according to claim 1, a photopolymerization initiator, and a polymerizable compound. A recording method in which an ink composition is attached and printing is performed on a recording medium, wherein the photocurable ink composition according to claim 3 is used as the ink composition, and then the light is irradiated by irradiating ultraviolet rays. A recording method for curing a curable ink composition. An inkjet recording method for performing printing by discharging droplets of an ink composition and attaching the droplets to a recording medium, wherein the photocurable ink composition according to claim 3 is used as the ink composition. Then, the recording method which hardens this photocurable ink composition by irradiating an ultraviolet-ray. Recorded matter has been printed by the recording method according to claim 4 or 5.