JP5568859B2 - Light-emitting diode curable inkjet ink and printed matter - Google Patents

Description

  The present invention relates to a light-emitting diode curable inkjet ink, a method for producing a cured product of the light-emitting diode curable inkjet ink, and a printed material.

  Conventional active energy ray-curable ink-jet inks are cured using a light source such as a mercury lamp or a metal halide lamp, and a photopolymerization initiator that matches the emission wavelength of those light sources is used. The ultraviolet irradiation light source as described above has a light emitting region over a wide wavelength region. For this reason, conventional active energy ray curable inks are used in combination with photopolymerization initiators having different absorption wavelengths.

  As described above, since the active energy ray-curable ink uses a photopolymerization initiator having a different absorption wavelength, it can cope with ink curing by a mercury lamp, a metal halide lamp, or the like, but an ultraviolet light having an emission peak wavelength in the range of 350 to 420 nm. In the light emitting diode UV-LED which generates the light, sufficient curing cannot be obtained.

  In addition, when these conventional active energy ray-curable inks are to be cured with UV-LEDs, it is necessary to use a photopolymerization initiator having absorption in the vicinity of a wavelength of 350 to 420 nm. Since it absorbs light in the wavelength range of 350 to 420 nm, there is a difference between whether the effect is large or small, but in many cases, even if a photopolymerization initiator having absorption at a wavelength of 350 to 420 nm is used, There was a problem that sufficient light energy could not be given to the photopolymerization initiator and the curability was poor.

  Furthermore, in the case of normal inkjet inks, overprinting is performed in yellow, magenta, cyan, and black. However, the thickness of the ink becomes thicker in areas where the color density of the printed matter is high or where the color overlaps. , The light transmittance decreases and the internal curability of the ink decreases. Therefore, an ink jet ink composition using a triazine initiator has been proposed as a method for imparting curability by UV-LED (see Patent Document 2). Furthermore, in the case of normal process inks, multi-color overprinting of ink is performed in the order of black, indigo, red, and yellow, but the thickness of the ink becomes thicker in areas where the color density of the printed matter is high or where the colors are superimposed. Therefore, the light transmittance decreases in the depth direction, and the internal curability of the ink decreases. Therefore, an ink jet ink composition using a triazine initiator has been proposed as a method for imparting curability by UV-LED (see Patent Document 2).

However, there is an inkjet ink having curing characteristics for active energy rays that can be said to be sufficiently satisfactory in all of various printing modes even by a triazine initiator, particularly UV-LEDs that emit ultraviolet rays having an emission peak wavelength in the range of 350 to 420 nm It is not necessarily obtained.
JP 2006-137183 A JP 2007-23151 A

  The inventors of the present invention have been designed with ultraviolet light generated by a light emitting diode (UV-LED) having curability by active energy rays and generating ultraviolet light in the range of 350 to 420 nm as a curing wavelength. An object of the present invention is to provide an active energy ray-curable ink having excellent photopolymerizability and curability upon irradiation, and excellent storage stability and printability as an inkjet ink.

  That is, the present invention provides 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or 2- (dimethylamino)-as the photocleavable photopolymerization initiator (A). 2-[(4-Methylphenyl) methyl] -1- (4-morpholinophenyl) -butan-1-one (A1) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide or bis (2, 4,6-trimethylbenzoyl) phenylphosphine oxide (A2) and 4,4′-dialkylaminobenzophenone as hydrogen abstraction type photopolymerization initiator (B) are used in combination as a light-emitting diode curable inkjet ink composition Related to things.

Furthermore, the present invention relates to the above-mentioned light-emitting diode curable ink-jet ink comprising a tertiary amine compound (C).
Furthermore, the present invention relates to the above-mentioned light-emitting diode curable inkjet ink, wherein C) is an aromatic tertiary amine compound.
Furthermore, the present invention relates to the above light-emitting diode curable inkjet ink, wherein C) is p-dimethylaminobenzoic acid ethyl ester.
Furthermore, the present invention relates to the light-emitting diode curable inkjet ink, which is used for curing a light-emitting diode that emits an emission line of 350 to 420 nm.

  Furthermore, the present invention relates to a multicolor set of the above-mentioned light-emitting diode curable ink-jet ink comprising at least yellow ink, magenta ink, cyan ink, and black ink.

  Further, the light-emitting diode curable inkjet ink curing according to the above, wherein the ink is overprinted, and the overprinted ink is collectively cured using a light emitting diode that emits a bright line of 350 to 420 nm after the overprint printing. The present invention relates to a method for manufacturing a product.

  Furthermore, it is related with the printed matter obtained using the manufacturing method of the above-mentioned ink hardened | cured material.

  According to the present invention, it has excellent curing characteristics against ultraviolet irradiation by light emitting diodes, particularly UV-LEDs that generate ultraviolet rays in the range of 350 to 420 nm, and also has surface curability and internal curability when overprinted. Can be obtained and can be used in various printed materials. Furthermore, when these various printed materials are printed, a light-emitting diode curable inkjet ink having excellent printability and storage stability can be obtained.

  As a printing ink, an active energy ray curable ink such as an ultraviolet curable ink is widely known, and in general, an electroded high pressure mercury lamp, an electroded metal halide lamp, an electrodeless high pressure mercury lamp, A light source that emits ultraviolet rays, such as an electrode metal halide lamp, is used. However, the conventional UV curable ink can provide a sufficient cured product when using the UV irradiation device as described above as an UV curing light source, but it has sufficient curing characteristics when using a monochromatic UV-LED. It is not a thing. The present invention can be printed and cured in the same manner as the conventional method even when such a conventionally known light source device for ultraviolet irradiation is used. In particular, UV-LED which is monochromatic light is used as the ultraviolet irradiation device. Even when used, it is possible to provide an ink that can obtain the same printing characteristics and curing characteristics as those obtained by using a conventional ultraviolet curable ink and curing using a conventional high-pressure mercury lamp or metal halide lamp. . In the light-emitting diode curable ink-jet ink of the present invention, such excellent printing characteristics and curing characteristics can be obtained not only in the case of single color printing but also in color overprinting, and quickly and beautifully printed matter. Can be obtained. Note that the light-emitting diode of the present invention is particularly preferably an ultraviolet ray in the range of 350 to 420 nm emitted from a UV-LED.

  The light-emitting diode curable inkjet ink of the present invention has 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or 2-as the photocleavable photopolymerization initiator (A). (Dimethylamino) -2-[(4-methylphenyl) methyl] -1- (4-morpholinophenyl) -butan-1-one (A1) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide Or bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (A2) and 4,4′-dialkylaminobenzophenone as a hydrogen abstraction type photopolymerization initiator (B) and, if necessary, a tertiary amine compound (C) is used in combination.

  As the photocleavable photopolymerization initiator (A), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or 2- (dimethylamino) -2-[(4- Methylphenyl) methyl] -1- (4-morpholinophenyl) -butan-1-one (A1) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide or bis (2,4,6- Trimethylbenzoyl) phenylphosphine oxide (A2) may be used alone or in combination of two or more, but it is particularly preferable to use (A1) and (A2) in combination.

  As the hydrogen abstraction type photopolymerization initiator (B) used in combination with the photocleavable photopolymerization initiator (A), 4,4′-dialkylaminobenzophenone is preferable.

  As the tertiary amine compound (C) used as necessary for the combination of the photocleavable photopolymerization initiator (A) and the hydrogen abstraction photopolymerization initiator (B), an aromatic tertiary amine compound is used. preferable. Examples of the aromatic tertiary amine compound include N, N-dimethylaniline, N, N-diethylaniline, N, N-dimethyl-p-toluidine, and N, N-dimethylamino-p-benzoic acid ethyl ester. N, N-dihydroxyethylaniline, triethylamine, N, N-dimethylhexylamine and the like. A tertiary amine compound (C) may be used independently and 2 or more types may be used together. Among these, N, N-dimethylamino-p-benzoic acid ethyl ester and N, N-dimethylamino-p-benzoic acid isoamyl ethyl ester are preferable.

  In the present invention, the photocleavable photopolymerization initiators (A1) and (A2) used in combination with the hydrogen abstraction photopolymerization initiator (B) are added in an amount of 0.5 to 10% by weight of (A1). , (A2) is preferably in the range of 0.5 to 10% by weight, and (B) is preferably in the range of 0.5 to 10% by weight, more preferably (A1) is 1 to 6% by weight, and (A2) is 1 to 6% by weight. % And (B) are preferably in the range of 1 to 6% by weight. Further, the addition amount of the tertiary amine (C) is preferably 10 to 100% by weight, more preferably 30 to 100% by weight with respect to the hydrogen abstraction type photopolymerization initiator.

  As described above, in the present invention, as the polymerization initiator, as the photocleavable photopolymerization initiator (A), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one Or 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- (4-morpholinophenyl) -butan-1-one (A1) and 2,4,6-trimethylbenzoyl-diphenyl- Phosphine oxide or bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide (A2) and 4,4′-dialkylaminobenzophenone as a hydrogen abstraction type photopolymerization initiator (B), and a third as necessary When used in combination with a secondary amine compound (C), excellent printing characteristics, including curing characteristics, even when UV-LED is used as the light source In which it is possible to obtain an active energy beam-curable ink having, but because not that became still unclear. However, it is estimated that this is due to the following.

  By using photoinitiators with different absorption wavelengths, the photoinitiator absorbs light efficiently with respect to the emission of the UV-LED, and the curability is improved. Further, it is considered that by using a tertiary amine compound having a small absorption at around 365 nm, this compound functions as a photopolymerization accelerator without inhibiting the light absorption of other photoinitiators.

  Components other than (A1), (A2), (B), and (C) of the light-emitting diode curable inkjet ink in the present invention can be used as long as the light-emitting diode curable inkjet ink can be obtained without impairing the effects of the present invention. Any of these may be used. Examples of such components include resins, pigments, acrylic group-containing compounds that are photopolymerizable compounds, and additives.

Examples of the resin include known ones added to conventional ink-jet inks. Examples of such resins include thermosetting or thermoplastic resins, such as polyvinyl chloride, polyester resins, poly (meth) acrylic acid esters, epoxy resins, polyurethane resins, cellulose derivatives (for example, ethyl cellulose, acetic acid). Cellulose, nitrocellulose), vinyl chloride vinyl acetate copolymer, polyamide resin, polyvinyl acetal resin, diallyl phthalate resin, and synthetic rubber such as butadiene-acrylonitrile copolymer. These resins can be used alone or in combination of two or more thereof.
In the present invention, the resin is preferably contained in the composition in the range of 0.5 to 20% by weight, more preferably in the range of 1 to 10% by weight.

As the pigment, inorganic pigments and organic pigments can be used. Inorganic pigments such as yellow lead, zinc yellow, bitumen, barium sulfate, cadmium red, titanium oxide, zinc white, petal, alumina white, calcium carbonate, ultramarine, carbon black, graphite, aluminum powder, etc. , Β-naphthol, β-oxynaphthoic acid, β-oxynaphthoic acid anilide, pyrazolone and other azo pigments, copper phthalocyanine blue, halogenated (chlorine or brominated) copper phthalocyanine blue, sulfonated copper phthalocyanine blue , Phthalocyanine pigments such as metal-free phthalocyanine, quinacridone, dioxazine, selenium (pyrantron, anthanthrone, indanthrone, anthrapyrimidine, flavantron, thioindigo, anthraquinone, perinone, perylene) Indolinone-based, metal complex, known various pigments such as polycyclic pigments and heterocyclic pigments such as quinophthalone can be used.
In the present invention, the pigment is preferably contained in the composition in the range of 0.5 to 30% by weight in order to obtain a sufficient concentration and sufficient light resistance.

  As the acrylic group-containing compound used in the present invention, an acrylic group-containing compound conventionally used in inkjet inks can be used. Examples of the acrylic group-containing monomer include a monofunctional monomer, a bifunctional monomer, a trifunctional or higher polyfunctional monomer, and the like.

Specific examples of the monofunctional acrylate monomer include alicyclic monomers such as cyclohexyl acrylate, 4-t-butylcyclohexyl acrylate, isobornyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate.
Heterocyclic monomers such as tetrahydrofurfuryl acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, acryloylmorpholine, N-vinylcaprolactam, N-vinylpyrrolidone, N-acryloyloxyethyl hexahydrophthalimide.
Aromatic cyclic monomers such as benzyl acrylate, methylphenoxyethyl acrylate, tribromophenyl acrylate, ethoxylated tribromophenyl acrylate, 2-phenoxyethyl acrylate (or its ethylene oxide / propylene oxide addition monomer), and the like.
2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, 3- Methoxybutyl acrylate, ethoxyethoxyethyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, dipropylene glycol acrylate, β-carboxylethyl acrylate, ethyl diglycol acrylate, trimethylolpropane formal monoacrylate, imide acrylate, isoamyl Acrylate, D Carboxylate of succinic acid acrylate, trifluoroethyl acrylate, .omega.-carboxypolycaprolactone monoacrylate, N- vinylformamide, there may be mentioned a monomer having no cyclic structure etc., but is not limited thereto. Moreover, you may use these compounds 1 type or 2 types or more as needed.

  Furthermore, among these acrylate monomers having high ink jet suitability, cyclohexyl acrylate, methylphenoxyethyl acrylate, 2-phenoxyethyl acrylate (or its ethylene oxide / or propylene oxide addition monomer), isobornyl acrylate, N-vinylcaprolactam, N-vinylpyrrolidone, 2-hydroxy-3-phenoxypropyl acrylate, 1,4-cyclohexanedimethanol monoacrylate, and N-acryloyloxyethylhexahydrophthalimide can be more preferably used.

  Furthermore, from the viewpoint of safety and coating film performance, methylphenoxyethyl acrylate, 2-phenoxyethyl acrylate (or its ethylene oxide alignment / propylene oxide addition monomer), isobornyl acrylate, N-vinylcaprolactam, 2- Hydroxy-3-phenoxypropyl acrylate and 1,4-cyclohexanedimethanol monoacrylate can be more preferably used.

  These compounds may be used alone or in combination of two or more as required.

  The monofunctional acrylate monomer is desirably 20% by weight or more and 97% by weight or less in the ink. When the content is 20% by weight or less, the viscosity of the ink becomes high, and the ink jetting cannot be performed. On the other hand, when the content is more than 97% by weight, curing with active energy rays is deteriorated, which is not suitable for practical use.

  Specific examples of the bifunctional acrylate monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and ethoxylated 1,6. -Hexanediol diacrylate, neopentyl glycol di (meth) acrylate, polypropylene glycol diacrylate, 1,4-butanediol di (meth) acrylate, 1,9-nonanediol diacrylate, tetraethylene glycol diacrylate, 2-n -Butyl-2-ethyl-1,3-propanediol diacrylate, hydroxypivalate neopentyl glycol diacrylate, 1,3-butylene glycol di (meth) acrylate, etoxy Tripropylene glycol diacrylate, neopentyl glycol modified trimethylolpropane diacrylate, stearic acid modified pentaerythritol diacrylate, neopentyl glycol oligoacrylate, 1,4-butanediol oligoacrylate, 1,6-hexanediol oligoacrylate, ethoxy Neopentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, bisphenol A diacrylate, dimethylol-tricyclodecane diacrylate, propoxylated bisphenol A di ( (Meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, bisphenol F diacrylate, etho Examples include but are not limited to silylated bisphenol F diacrylate, propoxylated bisphenol F diacrylate, cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane diacrylate, isocyanuric acid diacrylate, propoxylated isocyanuric acid diacrylate, and the like. Is not to be done. These compounds may be used alone or in combination of two or more as required.

  These bifunctional acrylate monomers are desirably 3% by weight or more and less than 80% by weight in the ink. If it is 3% by weight or less, curing with an active energy ray is deteriorated, which is not suitable for practical use. On the other hand, when the content is more than 90% by weight, the viscosity of the ink becomes high and it becomes impossible to eject by ink jet.

  Specific examples of trifunctional or higher acrylate monomers include trimethylolpropane triacrylate, hydroxypivalic acid trimethylolpropane triacrylate, ethoxylated phosphoric acid triacrylate, pentaerythritol triacrylate, tetramethylolpropane triacrylate, tetramethylolmethane triacrylate , Caprolactone modified trimethylolpropane triacrylate, propoxylate glyceryl triacrylate, trimethylolpropane oligoacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated isocyanuric acid triacrylate, tri (2-hydroxy Ethyl isocyanurate) triacrylate, tri (meta Triallyl isocyanurate, the pentaerythritol tetraacrylate and the like are not limited thereto. These compounds may be used alone or in combination of two or more as required.

  These tri- or higher functional monomers are desirably 30% by weight or less in the ink. If it is contained in an amount of more than 30% by weight, the viscosity of the ink becomes high and the ink jetting cannot be performed.

  Furthermore, UV-LED curable acrylic oligomers, urethane (meth) acrylates, epoxy (meth) acrylates, and polyester (meth) acrylates can also be used as appropriate. Examples of such oligomers include polyols, polybasic acids and esterified products of (meth) acrylic acid, and epoxy acrylate. As the above-mentioned polyol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol and the like are used. As the polybasic acid, phthalic anhydride, isophthalic acid, (anhydrous) succinic acid, (anhydrous) maleic acid, adipic acid, sebacic acid, etc. are used. The The esterification reaction of polyol, polybasic acid and (meth) acrylic acid is carried out by a conventional method.

  Examples of the urethane (meth) acrylate include general aromatic or aliphatic urethane (meth) acrylate. If an example is given, (meth) acrylates, such as tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc. will be mentioned.

  Examples of the epoxy (meth) acrylate include general aromatic or aliphatic epoxy (meth) acrylate. For example, (meth) acrylates such as bisphenol A epoxy, bisphenol F epoxy, novolac epoxy, and phosphoric acid epoxy are listed.

  Examples of the polyester (meth) acrylate include a general polyester (meth) acrylate, a fatty acid-modified type, and a chlorinated polyester.

    These UV-LED curable acrylic oligomers are desirably 30% by weight or less in the ink. If it is contained in an amount of more than 30% by weight, the viscosity of the ink becomes high and the ink jetting cannot be performed.

  Furthermore, other additives can be used in the printing ink as required.

  In the present invention, it is preferable to add a pigment dispersant in order to improve the dispersibility of the pigment and the storage stability of the ink. Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, a high molecular weight unsaturated acid ester, Polymer copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester, polyoxyethylene Nonylphenyl ether, stearylamine acetate, etc. can be used.

  Specific examples of the pigment dispersant include "Anti-Terra-U (polyaminoamide phosphate)", "Anti-Terra-203 / 204 (high molecular weight polycarboxylate)" manufactured by BYK Chemie, "Disperbyk-101 ( (Polyaminoamide phosphate and acid ester), 107 (hydroxyl group-containing carboxylic acid ester), 110, 111 (copolymer containing an acid group), 130 (polyamide), 161, 162, 163, 164, 165, 166, 170 ( Polymer copolymer) ”,“ 400 ”,“ Bykumen ”(high molecular weight unsaturated acid ester),“ BYK-P104, P105 (high molecular weight unsaturated acid polycarboxylic acid) ”,“ P104S, 240S (high molecular weight unsaturated) Saturated acid polycarboxylic acid and silicon system "," Lactimon (long chain amine and unsaturated acid poly) Recarboxylic acid and silicon) ”.

  Also, “Efka CHEMICALS” “Efka 44, 46, 47, 48, 49, 54, 63, 64, 65, 66, 71, 701, 764, 766”, “Efka Polymer 100 (modified polyacrylate), 150 (aliphatic) System modified polymer), 400, 401, 402, 403, 450, 451, 452, 453 (modified polyacrylate), 745 (copper phthalocyanine system) "," Floren TG-710 (urethane oligomer) "," Flownon "manufactured by Kyoeisha Chemical Co., Ltd. “SH-290, SP-1000”, “Polyflow No. 50E, No. 300 (acrylic copolymer)”, “Disparon KS-860, 873SN, 874 (polymer dispersing agent), # 2150 (manufactured by Enomoto Kasei Co., Ltd.) Aliphatic polyvalent carboxylic acid), # 7004 (polyether ester type) ” That.

  Further, “Demol RN, N (Naphthalenesulfonic acid formalin condensate sodium salt), MS, C, SN-B (aromatic sulfonic acid formalin condensate sodium salt), EP”, “Homogenol L-18 (poly) Carboxylic acid type polymer), “Emulgen 920, 930, 931, 935, 950, 985 (polyoxyethylene nonyl phenyl ether)”, “Acetamine 24 (coconut amine acetate), 86 (stearyl amine acetate)”, manufactured by Lubrizol "Solsperse 5000 (phthalocyanine ammonium salt type), 13940 (polyesteramine type), 17000 (fatty acid amine type), 24000GR, 32000, 33000, 39000, 41000, 53000", Nikko Chemical's "Nikkor T106 (poly Oxyethylene sorbitan monooleate), MYS-IEX (polyoxyethylene monostearate), Hexagline 4-0 (hexaglyceryl tetraoleate) ", Ajinomoto Fine Techno Co., Ltd." Azisper PB821, 822, 824, 827, 711 ", Tego Examples thereof include “TEGODisper685” manufactured by Chemiservice.

  The pigment dispersant is preferably contained in the composition in an amount of 0.1 to 10% by weight.

  In order to further improve the dispersibility of the pigment and the storage stability of the ink, it is preferable to add an acidic derivative of an organic pigment to the composition of the present invention when the pigment is dispersed.

In order to improve the wettability to the substrate, it is preferable to add a surface conditioner to the composition of the present invention. Specific examples of the surface conditioner include BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 340, 344, 370, and 375 manufactured by BYK-Chemie. 377, 350, 352, 354, 355, 356, 358N, 361N, 357, 390, 392, UV3500, UV3510, UV3570, “Tegorad-2100, 2200, 2250, 2500, 2700” manufactured by Tego Chemie. These surface conditioners may be used alone or in combination of two or more as required.
The surface conditioner is preferably contained in the composition in an amount of 0.001 to 1% by weight.

  In addition, additives such as ultraviolet absorbers, infrared absorbers, and antibacterial agents can be added according to the required performance. If necessary, photopolymerization initiators other than the above (A1), (A2), (B) and (C) may be used as additives.

  Hereinafter, the present invention will be described specifically by way of examples. In the examples, “parts” represents “parts by weight” and “%” represents “% by weight”.

First, Pigment Dispersion A was prepared with the following composition. Hereinafter, a dispersion was prepared by adding a pigment and a dispersant to a monomer, stirring the mixture with a high-speed mixer or the like until uniform, and then dispersing the obtained mill base with a horizontal sand mill for about 1 hour.
・ Solsperse 32000 (pigment dispersant manufactured by Avicia) 9.0 parts ・ Phenoxyethyl acrylate 61.0 parts

Also, Pigment Dispersion B was prepared with the following composition. The method for producing the dispersion was prepared by the same production method as that for Dispersion A.
・ Novoperm Yellow P-HG (Clariant Benzimidazolone Pigment) 35 parts ・ Solspers 24000 (Lubrisol Pigment Dispersant) 7 parts ・ Phenoxyethyl acrylate 58 parts

In addition, Pigment Dispersion C was prepared with the following composition. The method for producing the dispersion was prepared by the same production method as that for Dispersion A.
・ Hostaperm Red E5B02 (Clariant quinacridone pigment) 20 parts ・ Solspers 24000 (Lubrisol pigment dispersion) 6 parts ・ Phenoxyethyl acrylate 74 parts

Also, Pigment Dispersion D was prepared with the following composition. The method for producing the dispersion was prepared by the same production method as that for Dispersion A.
・ Special Black 350 (Degussa carbon black pigment) 30 parts ・ Solspers 32000 (Lubrisol pigment dispersion) 6 parts ・ Phenoxyethyl acrylate 64 parts

[Examples 1 to 7 and Comparative Examples 1 to 4]
An ink-jet ink was obtained by using the above-mentioned pigment dispersion to make an ink with the formulation described in Table 1.

<Evaluation of curability>
The inkjet ink obtained in Examples 1 to 7 and Comparative Examples 1 to 4 was printed on a vinyl chloride sheet (MD5 manufactured by Metamark Co., Ltd.) with a UVIJ printer (manufactured by Tritech Co., Ltd.), and LED system SPOT type ultraviolet light manufactured by Matsushita Electric Works, Ltd. After irradiating the LED using the curing device Aicure lamp head ANUJ61524 and transporting the printed matter at a conveyor speed of 50 m / min, the presence or absence of tack on the printed surface is checked with a finger, and the number of passes where tack has disappeared is determined. It was evaluated as “curability”.
<Evaluation of adhesion>
“Adhesion” repeats the pass on the conveyor until the surface tack disappears under the same conditions as the curability (up to 10 times), and the “adhesion” is achieved by peeling the cellotape (registered trademark) of the sample with no surface tack. evaluated.

  As a result, the printed materials of Examples 1 to 7 were cured without tack and had good adhesion, but the printed materials of Comparative Examples 1 and 2 had poor internal curability even when there was no surface tack. Insufficient ink peeled off the vinyl chloride sheet.

・ V-cap: N-vinyl caprolactone (manufactured by ISP)
NPGDA: Neopentyl glycol PO-modified diacrylate (manufactured by Cognis)
・ TPGDA: Tripropylene glycol diacrylate (manufactured by Daicel Cytec)
-PEA: 2-phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd.)
Irgacure 369: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one (manufactured by Ciba Japan)
Irgacure 379: 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- (4-morpholinophenyl) -butan-1-one (manufactured by Ciba Japan)
DAROCRE TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by Ciba Japan)
・ Irgacure 819: Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by Ciba Japan)
・ Dido EAB-SS: 4,4′-dialkylaminobenzophenone (Daido Kasei Kogyo Co., Ltd.)
-Kayacure EPA: p-dimethylaminobenzoic acid ethyl ester (manufactured by Nippon Kayaku Co., Ltd.)
・ Irgacure 184: 1-hydroxy-cyclohexyl-phenyl ketone (manufactured by Ciba Japan)

[Example 8]
Using the multicolor ink sets obtained in Examples 4 to 7, evaluation in the case of overprinting was performed. As a result of printing on a vinyl chloride sheet (MD5 manufactured by Metamark Co., Ltd.) using the UVIJ printer in the order of Black, Cyan, Magenta, Yellow, and irradiating the LED using the LED lamp head while changing the conveyor speed. A cured product having good adhesion in min was obtained.

In Examples, as a polymerization initiator, as a photocleavable photopolymerization initiator (A), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or 2- (dimethyl Amino) -2-[(4-methylphenyl) methyl] -1- (4-morpholinophenyl) -butan-1-one (A1) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide or bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (A2), 4,4′-dialkylaminobenzophenone as a hydrogen abstraction type photopolymerization initiator (B), and a tertiary amine compound (C )) In combination with a UV-LED as a light source, excellent curability and adhesion were obtained.
Also, a good cured product was obtained in overprinting.

On the other hand, in the comparative example, when UV-LED is used as the light source, sufficient curability and adhesion are not obtained.

Claims (9)

As photocleavable photopolymerization initiator (A), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one (A1) and 2,4,6-trimethylbenzoyl-diphenyl -Phosphine oxide or bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (A2) and 4,4'-dialkylaminobenzophenone as hydrogen abstraction type photopolymerization initiator (B) Light-emitting diode curable inkjet ink. The light-emitting diode curable inkjet ink according to claim 1, further comprising a tertiary amine compound (C). The light-emitting diode curable inkjet ink according to claim 2, wherein (C) is an aromatic tertiary amine compound. The light-emitting diode curable inkjet ink according to claim 3, wherein (C) is p-dimethylaminobenzoic acid ethyl ester. The light-emitting diode curable inkjet ink according to any one of claims 1 to 4, which is used for curing a light-emitting diode that emits a bright line of 350 to 420 nm. The multicolor set of light-emitting diode curable inkjet ink according to claim 1, comprising at least yellow ink, magenta ink, cyan ink, and black ink. A light-emitting diode curable inkjet ink cured product printed with the ink of the multicolor ink set according to claim 6 and cured with a light-emitting diode emitting an emission line of 350 to 420 nm. Production method. 8. The light-emitting diode curable inkjet ink curing method according to claim 7, wherein the ink is overprinted, and the overprinted ink is collectively cured using a light-emitting diode that emits an emission line of 350 to 420 nm after the overprint printing. Manufacturing method. A printed matter obtained using the method for producing an ink cured product according to claim 8.