JP2006298951A - Actinic radiation-curable inkjet ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actinic radiation-curable inkjet ink composition which has a low viscosity and an excellent adhesion. <P>SOLUTION: The actinic radiation-curable inkjet ink composition comprises a pigment, a pigment dispersing agent, a surface conditioner, and a monomer, wherein the monomer includes a urethane bond-containing monomer having one urethane bond and one ethylenic double bond in the molecule. The urethane bond-containing monomer accounts for 5-50 wt.% of the total of the monomers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an active energy ray-curable inkjet ink having a low viscosity and excellent adhesion.

Conventional inkjet inks with good water resistance include those in which oil-soluble dyes are dispersed or dissolved in high-boiling solvents and oil-soluble dyes in volatile solvents, but the dyes have various resistances such as light resistance. Therefore, an ink using a pigment as a colorant is desired. However, it is difficult to stably disperse the pigment in the organic solvent, and it is also difficult to ensure stable dispersibility and dischargeability. On the other hand, inks using high-boiling solvents cannot be printed on non-absorbing substrates because non-absorbing receivers do not volatilize the solvent in the ink and are difficult to dry by evaporation of the solvent. It is.

In an ink using a volatile organic solvent, good printing can be formed even on a non-absorbing substrate due to the adhesiveness of the resin used and the volatilization of the solvent. However, since a volatile solvent is the main component of the ink, drying by evaporation of the solvent on the nozzle surface of the head is very fast and frequent maintenance is required. Further, since ink essentially requires re-solubility in a solvent, sufficient resistance to the solvent may not be obtained.

In order to satisfy such characteristics, non-volatile monomers are used to prevent drying at the head, while on the other hand, a type of ink that is cured by applying an active energy ray is also used. The active energy ray-curable ink-jet ink is described in Patent Documents 1 to 5, but any ink is not suitable for practical use because it has low adhesion and high viscosity when printed directly on polyvinyl chloride. It was just a thing.

Japanese Patent Laid-Open No. 5-214280 JP-A-9-183929 JP 2002-167537 A JP-T-2004-518787 Japanese Patent No. 3619778

An object of the present invention is to provide an active energy ray-curable ink-jet ink that has good ejection stability and in particular has excellent solvent resistance and adhesion of a cured film formed on an ink-absorbing medium.

That is, the present invention relates to an active energy ray-curable inkjet ink comprising a pigment, a pigment dispersant, a surface conditioner and a monomer, the monomer containing a urethane bond having one urethane bond and an ethylenic double bond in the molecule. An active energy ray-curable ink-jet ink comprising a monomer, wherein the urethane bond-containing monomer is contained in an amount of 5 to 50% by weight in all monomers.
About.

Furthermore, the present invention relates to the active energy ray-curable inkjet ink as described above, wherein the number average molecular weight of the urethane bond-containing monomer is 200 or more and 1000 or less.
Furthermore, the present invention relates to the active energy ray-curable inkjet ink as described above, wherein the urethane bond-containing monomer has a viscosity at 25 ° C. of 1 to 2000 mPa · s.
Furthermore, the present invention provides the active energy ray-curable inkjet as described above, wherein the urethane bond-containing monomer is produced from an isocyanatoalkyl (meth) acrylate and a compound having one hydroxyl group and an ethylenic double bond. It relates to ink.
Furthermore, the present invention relates to a printed matter obtained by forming an image on a substrate with the above-described active energy ray-curable inkjet ink and then curing the ink with active energy rays.

According to the present invention, an active energy ray curable inkjet ink having low viscosity, good ejection stability, excellent curability, and particularly excellent solvent resistance and adhesion of a cured film formed on an ink non-absorbent medium. Could be provided.

The urethane bond-containing monomer constituting the active energy ray-curable inkjet ink of the present invention is a monomer having one urethane bond and an ethylenic double bond in the molecule. This monomer has a lower viscosity than a conventional urethane bond-containing acrylate, and is suitable as a monomer for an active energy ray-curable inkjet ink having a large viscosity restriction.

The urethane bond-containing monomer of the present invention is produced from a compound (N) having one isocyanato group and a compound (H) having one hydroxyl group, and either or both of the compound (N) and the compound (H). And having an ethylenic double bond. Monomers with two or more ethylenic double bonds that use ethylenic double bonds in both cases, the accumulated light amount of the required active energy rays is low, or the printed material after curing with active energy rays Is preferable in that it may be improved.

As the compound (N) having one isocyanato group, those having no ethylenic double bond are methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, hexyl isocyanate, cyclohexyl isocyanate, isocyanate Examples thereof include phenyl isocyanate, and those having an ethylenic double bond include vinyl isocyanate, allyl isocyanate, isocyanate (meth) acryloyl, isocyanatoalkyl (meth) acrylate and the like. Of these, isocyanatoalkyl (meth) acrylate is preferably used.

As the compound (H) having one hydroxyl group, those having no ethylenic double bond are methanol, ethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, heptanol, octanol, nonanol, decanol, dodecanol, 3 -Methoxybutyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, one-end methoxylated polyethylene glycol, One-end methoxylated polypropylene glycol, one-end methoxylated poly Examples include butylene glycol, and those having an ethylenic double bond include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meta ) Acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, caprolactone modified (1-10 mol) 2-hydroxyethyl (meth) acrylate, caprolactone modified (1 -10 mol) 2-hydroxypropyl (meth) acrylate, caprolactone-modified (1-10 mol) 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, Ripropylene glycol mono (meth) acrylate, poly (ethylene glycol / propylene glycol) mono (meth) acrylate, (polyethylene glycol-block-polypropylene glycol) mono (meth) acrylate, poly (ethylene glycol / tetramethylene glycol) mono (meta ) Acrylate, poly (propylene glycol / tetramethylene glycol) mono (meth) acrylate, polytetramethylene glycol-propylene glycol mono (meth) acrylate, fatty acid modified glycidyl (meth) acrylate, oleic acid modified glycidyl (meth) acrylate, soybean oil Fatty acid-modified glycidyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerin di (meth) acrylate Lilate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and other product names are Osaka Organic Chemical Co., Ltd. Biscoat # 2308, Biscoat # 2323, Toagosei Examples include Aronix M-215 manufactured by Corporation.

As a combination of the compound (N) and the compound (H), isocyanatoalkyl (meth) acrylate is used for the compound (N), and ethylene produced using the compound (H) having an ethylenic double bond A urethane bond-containing monomer having two or more ionic double bonds is preferable in that the curing sensitivity becomes high or the resistance of a printed material after curing may be improved by an active energy ray.

Further, from the viewpoint of adhesion and sensitivity of polyvinyl chloride, preferably compound (N) isocyanatoalkyl (meth) acrylate, compound (H) is cyclohexanedimethanol monoacrylate, caprolactone-modified (1 to 10 mol) 2-hydroxyethyl. Acrylate, caprolactone modified (1-10 mol) 2-hydroxypropyl acrylate, caprolactone modified (1-10 mol) 4-hydroxybutyl acrylate, poly (ethylene glycol / tetramethylene glycol) monoacrylate or poly (propylene glycol / tetramethylene glycol) mono Acrylate and polytetramethylene glycol-propylene glycol monoacrylate are used, and more preferably 2-isocyanatoethyl (medium) is added to compound (N). ) Acrylate, and caprolactone-modified (1-10 mol) 2-hydroxyethyl acrylate is used for compound (H), most preferably 2-isocyanatoethyl (meth) acrylate is used for compound (N) and compound (H ) Using caprolactone-modified (2-4 mol) 2-hydroxyethyl acrylate.

For the reaction of the compound (N) and the compound (H), a known catalyst can be used as the catalyst used for the production of the acidic group-containing urethane resin of the present invention. Examples thereof include tertiary amine compounds and organometallic compounds.

Examples of tertiary amine compounds include triethylamine, triethylenediamine, N, N-dimethylbenzylamine, N-methylmorpholine, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo. -[4.3.0] -5-Nonene etc. are mentioned.

Examples of organometallic compounds include tin compounds and non-tin compounds. Examples of the tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, Examples include tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like. Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, and lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate. Iron, such as iron 2-ethylhexanoate and iron acetylacetonate, cobalt-based such as cobalt benzoate and cobalt 2-ethylhexanoate, zinc-based such as zinc naphthenate and zinc 2-ethylhexanoate, naphthene Examples thereof include zirconium acid. These can be used alone or in combination.

In the production of the urethane bond-containing monomer of the present invention, it is preferable not to use a solvent, but acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate, toluene, xylene, Acetonitrile or the like may be used.

The reaction temperature for obtaining the urethane bond-containing monomer of the present invention is preferably 40 to 150 ° C. More preferably, it is 50-100 degreeC.

The urethane bond-containing monomer of the present invention preferably has a number average molecular weight of 200 or more and 1,000 or less. When the number average molecular weight is less than 200, the polyvinyl chloride adhesion is insufficient, and when it exceeds 1000, the printed matter after curing has insufficient resistance. More preferably, it is a case of 300-800.

The urethane bond-containing monomer of the present invention preferably has a viscosity at 25 ° C. of 1 to 2000 mPa · s. Those less than 1 are difficult to make in practice, and those exceeding 2000 mPa · s have a low viscosity of urethane bond-containing monomers that can be blended into inkjet ink due to viscosity restrictions, and the polyvinyl chloride adhesion expected for urethane bond-containing monomers May not develop. Moreover, what crystallizes at 25 degreeC is unpreferable at the point of handling.

Specific examples of the monomer used in the present invention include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and ethoxy. 1,6-hexanediol diacrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, tripropylene 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, dimethylol-tricyclodecane diacrylate, hydroxypivalic acid neopentyl glycol diacrylate, 1,3-butylene glycol di (meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, Propoxylated bisphenol A di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane diacrylate, trimethylolpropane triacrylate, hydroxypivalic acid trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, Propoxylated trimethylolpropane triacrylate, ethoxylated phosphate triacrylate, ethoxylated tripropyleneglycol Diacrylate, neopentyl glycol modified trimethylolpropane diacrylate, stearic acid modified pentaerythritol diacrylate, pentaerythritol triacrylate, tetramethylolpropane triacrylate, tetramethylol methane triacrylate, pentaerythritol tetraacrylate, caprolactone modified trimethylolpropane triacrylate , Ethoxylated isocyanuric acid triacrylate, tri (2-hydroxyethyl isocyanurate) triacrylate, propoxylate glyceryl triacrylate, tetramethylol methane tetraacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate Chryrate, dipentaerythritol hexaacrylate, caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, neopentyl glycol oligoacrylate, 1,4-butanediol oligoacrylate, 1,6-hexanediol oligoacrylate, trimethylolpropane Oligoacrylate, pentaerythritol oligoacrylate, 2-phenoxyethyl acrylate, acryloylmorpholine, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, isobornyl Acrylate, cyclohexyl acrylate, -Methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, benzyl acrylate, ethoxyethoxyethyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, Methylphenoxyethyl acrylate, dipropylene glycol acrylate, β-carboxyl ethyl acrylate, phenoxy diethylene glycol acrylate, vinyl caprolactam, vinyl pyrrolidone, N-vinyl formamide, ethyl diglycol acrylate, trimethylolpropane formal monoacrylate, 4-t-butylcyclohex Acrylate, tri (meth) allyl isocyanurate, imide acrylate, isoamyl acrylate, ethoxylated succinic acid acrylate, caprolactone modified tetrahydrofurfuryl acrylate, tribromophenyl acrylate, ethoxylated tribromophenyl acrylate, trifluoroethyl acrylate, ω-carboxyl Examples include polycaprolactone monoacrylate. These compounds may be used alone or in combination of two or more as required.

  The ink-jet ink of the present invention can use what are called oligomers and prepolymers in addition to the above monomers. Specifically, “Ebecryl 230, 244, 245, 270, 280 / 15IB, 284, 285, 4830, 4835, 4858, 4883, 8402, 8803, 8800, 254, 264, 265, 294 / 35HD, manufactured by Daicel UCB, 1259, 1264, 4866, 9260, 8210, 1290.1290K, 5129, 2000, 2001, 2002, 2100, KRM7222, KRM7735, 4842, 210, 215, 4827, 4849, 6700, 6700-20T, 204, 205, 6602, 220, 4450, 770, IRR567, 81, 84, 83, 80, 657, 800, 805, 808, 810, 812, 1657, 1810, IRR302, 450, 670, 830, 835, 870, 1 30, 1870, 2870, IRR267, 813, IRR483, 811, 436, 438, 446, 505, 524, 525, 554W, 584, 586, 745, 767, 1701, 1755, 740 / 40TP, 600, 601, 604, 605, 607, 608, 609, 600 / 25TO, 616, 645, 648, 860, 1606, 1608, 1629, 1940, 2958, 2959, 3200, 3201, 3404, 3411, 3412, 3415, 3500, 3502, 3600, 3603, 3604, 3605, 3608, 3700, 3700-20H, 3700-20T, 3700-25R, 3701, 3701-20T, 3703, 3702, RDX63182, 6040, IRR419 ", manufactured by Sartomer CN104, CN120, CN124, CN136, CN151, CN2270, CN2271E, CN435, CN454, CN970, CN971, CN972, CN9782, CN981, CN9873, CN991, "Laromar EA81L, F87" manufactured by BASF LR8800, PE46T, LR8907, PO43F, PO77F, PE55F, LR8967, LR8981, LR8982, LR8992, LR9004, LR8956, LR8985, LR8987, UP35D, UA19T, LR9005, PO83F, PO33F, L8489, L9489 LR8996, LR9013 LR9019, PO9026V, PE9027V "manufactured by Cognis" Photomer 3005, 3015, 3016, 3072, 3982, 3215, 5010, 5429, 5430, 5432, 5662, 5806, 5930, 6008, 6010, 6019, 6184, 6210, 6217, 6230, 6891, 6892, 6893-20R, 6363, 6572, 3660 "," Art Resin UN-9000HP, 9000PEP, 9200A, 7600, 5200, 1003, 1255, 3320HA, 3320HB, 3320HC, 3320HS, 901T, manufactured by Negami Kogyo Co., Ltd. 1200TPK, 6060PTM, 6060P "," Nippon Gosei Chemical Co., Ltd. "" purple light UV-6630B, 7000B, 7510B, 7461TE, 3000B, 320 " 0B, 3210EA, 3310B, 3500BA, 3520TL, 3700B, 6100B, 6640B, 1400B, 1700B, 6300B, 7550B, 7605B, 7610B, 7620EA, 7630B, 7640B, 2000B, 2010B, 2250EA, 2750B, “Kayarad” R-280, R-146, R131, R-205, EX2320, R190, R130, R-300, C-0011, TCR-1234, ZFR-1122, UX-2201, UX-2301, UX3204, UX-3301, UX-4101, UX-6101, UX-7101, MAX-5101, MAX-5100, MAX-3510, UX-4101 "and the like.

  As the pigment contained in the inkjet ink of the present invention, an achromatic pigment such as carbon black, titanium oxide, calcium carbonate, or a chromatic organic pigment can be used. Examples of organic pigments include insoluble azo pigments such as Toluidine Red, Toluidine Maroon, Hansa Yellow, Benzidine Yellow, and Pyrazolone Red, soluble azo pigments such as Ritol Red, Helio Bordeaux, Pigment Scarlet, and Permanent Red 2B, alizarin, indanthrone, and thioindigo. Derivatives from vat dyes such as maroon, phthalocyanine organic pigments such as phthalocyanine blue and phthalocyanine green, quinacridone organic pigments such as quinacridone red and quinacridone magenta, perylene organic pigments such as perylene red and perylene scarlet, isoindolinone yellow , Isoindolinone organic pigments such as isoindolinone orange, pyranthrone organic pigments such as pyranthrone red and pyranthrone orange, thioy Digo-based organic pigments, condensed azo-based organic pigments, benzimidazolone-based organic pigments, quinophthalone-based organic pigments such as quinophthalone yellow, isoindoline-based organic pigments such as isoindoline yellow, and other pigments such as flavanthrone yellow and acylamide yellow Nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like.

  When organic pigments are exemplified by color index (CI) numbers, CI Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 8893, 109, 110, 117, 120, 125, 128, 129, 137 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185, CI Pigment Orange 16, 36, 43, 51, 55, 59, 61, CI Pigment Red 9, 48 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240 , CI Pigment Violet 19, 23, 29, 30, 37, 40, 50, CI Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, C.I. Pigment Green 7, 36, C.I. Pigment Brown 23, 25, 26, and the like.

  Specific examples of carbon black include “Special Black 350, 250, 100, 550, 5, 4, 4A, 6” “Printex U, V, 140 U, 140 V, 95, 90, 85, 80, 75, 55, manufactured by Degussa. 45, 40, P, 60, L6, L, 300, 30, 3, 35, 25, A, G ", Cabot's" REGAL 400R, 660R, 330R, 250R "," MOGUL E, L ", Mitsubishi Chemical “MA7, 8, 11, 77, 100, 100R, 100S, 220, 230” “# 2700, # 2650, # 2600, # 200, # 2350, # 2300, # 2200, # 1000, # 990, # 980, # 970, # 960, # 950, # 900, # 850, # 750, # 650, # 52, # 50, # 47, # 45, # 4 5L, # 44, # 40, # 33, # 332, # 30, # 25, # 20, # 10, # 5, CF9, # 95, # 260 ”and the like.

  Specific examples of titanium oxide include “Taipeku CR-50, 50-2, 57, 80, 90, 93, 95, 953, 97, 60, 60-2, 63, 67, 58, 58- manufactured by Ishihara Sangyo Co., Ltd. 2, 85 "" Tipekes R-820, 830, 930, 550, 630, 680, 670, 580, 780, 780-2, 850, 855 "," Tipekes A-100, 220 "," Tipekes W-10 "," Tipekes " PF-740, 744 "" TTO-55 (A), 55 (B), 55 (C), 55 (D), 55 (S), 55 (N), 51 (A), 51 (C) " "TTO-S-1, 2", "TTO-M-1, 2", "Titanics JR-301, 403, 405, 600A, 605, 600E, 603, 805, 806, 701, 800, 808" manufactured by Teika "Titanic EN-1, C, 3, 4, 5 ", DuPont" Taipyua R-900,902,960,706,931 ', and the like.

  Among the above pigments, quinacridone organic pigments, phthalocyanine organic pigments, benzimidazolone organic pigments, isoindolinone organic pigments, condensed azo organic pigments, quinophthalone organic pigments, isoindoline organic pigments, etc. are light-resistant. Is preferable because it is excellent. The organic pigment is preferably a fine pigment having an average particle diameter of 10 to 150 nm as measured by laser scattering. When the average particle diameter of the pigment is less than 10 nm, the light resistance is lowered due to the small particle diameter, and when it exceeds 150 nm, it is difficult to maintain stable dispersion, and the pigment is likely to precipitate.

The organic pigment can be refined by the following method. That is, a mixture comprising at least three components of an organic pigment, a water-soluble inorganic salt that is at least 3 times the weight of the organic pigment, and a water-soluble solvent is made into a clay-like mixture, and is kneaded strongly with a kneader or the like and then refined. And stirred with a high speed mixer or the like to form a slurry. Next, filtration and washing of the slurry are repeated to remove the water-soluble inorganic salt and the water-soluble solvent. In the miniaturization step, a resin, a pigment dispersant and the like may be added.
Examples of the water-soluble inorganic salt include sodium chloride and potassium chloride. These inorganic salts are used in the range of 3 times by weight or more, preferably 20 times by weight or less of the organic pigment. When the amount of the inorganic salt is less than 3 times by weight, a treated pigment having a desired size cannot be obtained. On the other hand, when the amount is more than 20 times by weight, the washing process in the subsequent process is great, and the substantial amount of the organic pigment is reduced.

  The water-soluble solvent is an organic solvent and a water-soluble inorganic salt that is used as a crushing aid, and is used for efficient crushing efficiently, especially if it is a solvent that dissolves in water. Although not limited, a high boiling point solvent having a boiling point of 120 to 250 ° C. is preferable from the viewpoint of safety because the temperature rises during kneading and the solvent is easily evaporated. Examples of water-soluble solvents include 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether , Triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, low molecular weight Examples thereof include polypropylene glycol.

  In the present invention, the pigment is preferably contained in the ink-jet ink in the range of 3 to 15% by weight in order to obtain a sufficient concentration and sufficient light resistance.

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 dispersant include “Anti-Terra-U (polyaminoamide phosphate)”, “Anti-Terra-203 / 204 (high molecular weight polycarboxylate)”, “Disperbyk-101” (polyamino) manufactured by BYK Chemie. Amide phosphate and acid ester), 107 (hydroxyl group-containing carboxylic acid ester), 110, 111 (copolymer containing acid group), 130 (polyamide), 161, 162, 163, 164, 165, 166, 170 (high Molecular 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) Acid polycarboxylic acid and silicon) "," Lactimon (long-chain amine and unsaturated acid polycarbonate) Rubonic 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 nonylphenyl ether)”, “Acetamine 24 (coconut amine acetate), 86 (stearyl amine acetate)”, “Abisia” Solspers 5000 (phthalocyanine ammonium salt type), 13940 (polyesteramine type), 17000 (fatty acid amine type), 24000GR, 32000, 33000, 39000, 41000, 53000, “Nikkor T106 (polyoxy) manufactured by Nikko Chemical Co., Ltd. Ethylene sorbitan monooleate), MYS-IEX (polyoxyethylene monostearate), Hexagline 4-0 (hexaglyceryl tetraoleate), “Ajisper PB821, 822, 824” manufactured by Ajinomoto Fine Techno Co., etc.

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

  It is preferable to add a surface conditioner to the inkjet ink of the present invention in order to improve the wettability to the substrate. 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 ink in an amount of 0.001 to 1% by weight.

In the present invention, when ultraviolet rays are used as active energy rays, a radical photopolymerization initiator is blended in the ink. As the photopolymerization initiator, a molecular cleavage type or a hydrogen abstraction type is suitable for the present invention. Specific examples include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4- Morpholinophenyl) -butan-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like are preferably used, and as other molecular cleavage types, 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane- 1-one and 2-me Ru-1- (4-methylthiophenyl) -2-morpholinopropan-1-one or the like may be used in combination, and further, a hydrogen abstraction type photopolymerization initiator, benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-Benzoyl-4′-methyl-diphenyl sulfide and the like can be used in combination.

For the photo radical polymerization initiator, as sensitizers, for example, trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N, An amine that does not cause an addition reaction with the polymerizable component, such as N-dimethylbenzylamine and 4,4′-bis (diethylamino) benzophenone, can also be used in combination. Of course, it is preferable to select and use the radical photopolymerization initiator and the sensitizer, which are excellent in solubility in the ultraviolet curable compound and do not inhibit the ultraviolet transmittance.

The radical photopolymerization initiator and the sensitizer are used in the range of 0.1 to 20% by mass, preferably 4 to 12% by mass, based on the total amount of the ultraviolet curable composition.

  The inkjet ink of the present invention is polymerized with hydroquinone, p-methoxyphenol, t-butylcatechol, pyrogallol, butylhydroxytoluene, etc., in order to increase the stability of the ink over time and the on-machine stability in the recording apparatus. It is preferable to blend the inhibitor in an amount of 0.01 to 5% by weight in the ink.

The active energy ray-curable inkjet ink of the present invention can use various additives such as a plasticizer, a surface conditioner, an ultraviolet light inhibitor, a light stabilizer, and an antioxidant.

  The ink-jet ink of the present invention is produced by well dispersing a pigment together with a monomer and a pigment dispersant using an ordinary dispersing machine such as a sand mill. It is preferable to prepare a concentrated solution having a high pigment concentration in advance and dilute with a monomer. Sufficient dispersion is possible even with dispersion by a normal disperser. Therefore, excessive dispersion energy is not required, and a large amount of dispersion time is not required. An ink having excellent properties is prepared. The ink is preferably filtered through a filter having a pore size of 3 μm or less, and more preferably 1 μm or less.

The inkjet ink of the present invention is preferably adjusted to have a high viscosity at 25 ° C. of 5 to 50 mPa · s. An ink having a viscosity of 5 to 50 mPa · s at 25 ° C. exhibits stable ejection characteristics, particularly from a head having a normal frequency of 4 to 10 KHz to a head having a high frequency of 10 to 50 KHz.
When the viscosity is less than 5 mPa · s, a decrease in the follow-up property of the discharge is recognized in the high-frequency head. When the viscosity exceeds 50 mPa · s, even if a mechanism for reducing the viscosity by heating is incorporated in the head, the discharge itself A drop occurs, the ejection stability becomes poor, and the ejection cannot be performed at all.

  The ink-jet ink of the present invention preferably has an electric conductivity of 10 μS / cm or less in the piezo head and does not cause electrical corrosion inside the head. Further, in the continuous type, it is necessary to adjust the electric conductivity by the electrolyte. In this case, it is necessary to adjust the electric conductivity to 0.5 mS / cm or more.

  In order to use the ink-jet ink of the present invention, first, the ink-jet ink is supplied to a printer head of a printer for an ink-jet recording system, discharged from the printer head onto a substrate, and then an active energy ray such as an ultraviolet ray or an electron beam is applied. Irradiate. This quickly cures the composition on the print medium.

  In addition, as a light source of an active energy ray, when irradiating an ultraviolet-ray, a high pressure mercury lamp, a metal halide lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, an ultraviolet laser, and sunlight can be used, for example. When cured with an electron beam, it is usually cured with an electron beam having an energy of 300 eV or less, but it can also be cured instantaneously with an irradiation dose of 1 to 5 Mrad.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not particularly limited to the examples. In the examples, “part” represents “part by weight”. The molecular weight is a weight average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography).
(Synthesis Example 1)

2-hydroxyethyl acrylate in which 2 mol of caprolactone is added to a hydroxyl group in a 5-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, a thermometer, and a dropping funnel (manufactured by Daicel Chemical Industries, Ltd .: Plaxel) FA2D) was charged 105.0 parts, dibutyltin dilaurate 0.05 parts, hydroquinone monomethyl ether 0.15 parts, and the temperature was raised to 80 ° C. while introducing dry air. Separately, 45.0 parts of 2-isocyanatoethyl methacrylate was charged into the dropping funnel and dropped into the separable flask over 2 hours with stirring. After completion of the dropwise addition, stirring was continued at 80 ° C. for 3 hours, and then it was confirmed by infrared absorption spectrum that there was no absorption peak of isocyanato group, and the reaction was completed. The viscosity of the product at 25 ° C. was 340 mPa · s, the number average molecular weight was 514, and the weight average molecular weight was 657.
(Synthesis Example 2)

To a 5-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, a thermometer, and a dropping funnel, 86.0 of 1,4-cyclohexanedimethanol monoacrylate (manufactured by Nippon Kasei Chemical Co., Ltd .: CHDMMA). Parts, dibutyltin dilaurate 0.05 parts, hydroquinone monomethyl ether 0.15 parts were charged, and the temperature was raised to 80 ° C. while introducing dry air. Separately, 64.0 parts of 2-isocyanatoethyl methacrylate was charged into a dropping funnel and dropped into a separable flask over 2 hours with stirring. After completion of the dropwise addition, stirring was continued at 80 ° C. for 3 hours, and it was confirmed by infrared absorption spectrum that there was no absorption peak of the isocyanate group, and the reaction was completed. The viscosity of the product at 25 ° C. was 1200 mPa · s, the number average molecular weight was 336, and the weight average molecular weight was 359.
(Synthesis Example 3)

A compound in which 1 mol of propylene oxide and 6 mol of tetrahydrofuran are added to acrylic acid in a 5-neck separable flask equipped with a stirrer, reflux condenser, gas inlet tube, thermometer, and dropping funnel (Nippon Yushi Co., Ltd .: BLEMMER 10APB) -500B) was charged with 93.3 parts, dibutyltin dilaurate with 0.05 parts, and hydroquinone monomethyl ether with 0.15 parts, and the temperature was raised to 80 ° C. while introducing dry air. Separately, 56.7 parts of 2-isocyanatoethyl methacrylate was charged into the dropping funnel and dropped into the separable flask over 2 hours with stirring. After completion of the dropwise addition, stirring was continued at 80 ° C. for 3 hours, and then it was confirmed by infrared absorption spectrum that there was no absorption peak of isocyanato group, and the reaction was completed. The viscosity of the product at 25 ° C. was 500 mPa · s, the number average molecular weight was 396, and the weight average molecular weight was 418.
(Synthesis Example 4)

In a 5-neck separable flask equipped with a stirrer, reflux condenser, gas inlet tube, thermometer, and dropping funnel, 73.0 parts 4-hydroxybutyl acrylate, 0.05 parts dibutyltin dilaurate, hydroquinone monomethyl 0.15 part of ether was charged, and the temperature was raised to 80 ° C. while introducing dry air. Separately, 77.0 parts of 2-isocyanatoethyl methacrylate was charged into the dropping funnel and dropped into the separable flask over 2 hours with stirring. After completion of the dropwise addition, stirring was continued at 80 ° C. for 3 hours, and it was confirmed by infrared absorption spectrum that there was no absorption peak of the isocyanate group, and the reaction was completed. The viscosity of the product at 25 ° C. was 80 mPa · s, the number average molecular weight was 277, and the weight average molecular weight was 284.

Pigment dispersion A was prepared with the following composition. This dispersion was prepared by adding a pigment and a dispersant into an organic solvent, stirring until uniform with a high speed mixer or the like, and dispersing the obtained mill base with a horizontal sand mill for about 1 hour.
LIONOL BLUE FG-7400G (phthalocyanine pigment manufactured by Toyo Ink Manufacturing Co., Ltd.) 30.0 parts Solspurs 32000 (pigment dispersant manufactured by Avicia) 9.0 parts 2-phenoxyethyl acrylate 61.0 parts

Further, Pigment Dispersion B was prepared with the following composition. This dispersion was prepared by adding a pigment and a dispersant to an organic solvent, 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 1.5 hours.
・ Yellow Pigment E4GN (Nickel Complex Azo Pigment manufactured by Bayer)
35.0 parts ・ Solspers 32000 (pigment dispersant manufactured by Avicia) 7.0 parts ・ 2-phenoxyethyl acrylate 58.0 parts

Further, Pigment Dispersion C was prepared with the following composition. This dispersion was prepared by adding a pigment and a dispersant into an organic solvent, stirring the mixture with a high speed mixer or the like until uniform, and then dispersing the resulting mill base with a horizontal sand mill for about 2 hours.
・ Hostaper Red E5B02 (Clariant quinacridone pigment) 20.0 parts ・ Solspers 32000 (Abisia pigment dispersant) 6.0 parts ・ 2-phenoxyethyl acrylate 74.0 parts

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
Pigment dispersion A 11.4 parts 2-phenoxyethyl acrylate 40.0 parts BYK-331 (silicon resin manufactured by BYK Chemie) 0.1 part Tripropylene glycol diacrylate 15.7 parts Ethoxylated trimethylo- 20.0 parts of lepropane triacrylate / urethane bond-containing monomer obtained in Synthesis Example 1 4.8 parts / Irgacure 907 (photo radical polymerization initiator manufactured by Ciba Specialty Chemicals) 4.0 parts / Irgacure 819 (Ciba Specialty Chemicals) 4.0 parts photo radical polymerization initiator)

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
-Pigment dispersion B 8.6 parts-2-phenoxyethyl acrylate 11.8 parts-Propoxylated neopentyl glycol diacrylate 28.0 parts-BYK-361N (acrylic resin manufactured by BYK Chemie) 0.1 part-Synthesis example 43.5 parts of the urethane bond-containing monomer obtained in Step 2 • Irgacure 907 (Ciba Specialty Chemicals photo radical polymerization initiator) 3.0 parts • Irgacure 819 (Ciba Specialty Chemicals photo radical polymerization initiator) 5.0 Part

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
Pigment dispersion C 16.5 parts Isobonyl acrylate 2.5 parts Hydroxypivalic acid neopentyl glycol diacrylate 28.4 parts Ethoxylated trimethylolpropane triacrylate 23.0 parts BYK-UV3510 (BYK Chemie 0.1 part. Urethane bond-containing monomer obtained in Synthesis Example 3 21.5 parts. Irgacure 907 (photo radical polymerization initiator manufactured by Ciba Specialty Chemicals Co., Ltd.) 3.0 parts Irgacure 819 (Ciba Specialty) Chemicals photo radical polymerization initiator) 5.0 parts

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
-Pigment dispersion C 16.5 parts-2-phenoxyethyl acrylate 2.5 parts-Tripropylene glycol diacrylate 18.0 parts-Laromar PO94F (polyether acrylate manufactured by BASF)
23.4 parts ・ Ethoxylated trimethylolpropane triacrylate 23.0 parts ・ BYK-UV3510 (silicon resin manufactured by BYK Chemie) 0.1 part ・ Urethane bond-containing monomer obtained in Synthesis Example 4 8.5 parts ・ Irgacure 907 (Ciba Specialty Chemicals photo radical polymerization initiator) 3.0 parts Irgacure 819 (Ciba Specialty Chemicals photo radical polymerization initiator) 5.0 parts (Comparative Example 1)

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
・ Pigment dispersion C 16.5 parts ・ Isobornyl acrylate 2.5 parts ・ Tripropylene glycol diacrylate 18.0 parts ・ Ethoxylated trimethylolpropane triacrylate 23.0 parts ・ BYK-UV3510 (Sold by BYK Chemie, Silicon) Resin) 0.1 part ・ Ebecryl 270 (urethane oligomer made by Daicel UCB) 3.5 parts ・ Irgacure 907 (photo radical polymerization initiator made by Ciba Specialty Chemicals) 3.0 parts ・ Irgacure 819 (light radical made by Ciba Specialty Chemicals) Polymerization initiator) 5.0 parts (Comparative Example 2)

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
-Pigment dispersion B 8.5 parts-2-phenoxyethyl acrylate 2.5 parts-N-vinylcaprolactam 40.0 parts-Tripropylene glycol diacrylate 18.0 parts-Ethoxylated trimethylolpropane triacrylate 23.0 parts BYK-UV3510 (silicon resin manufactured by BYK Chemie) 0.1 part Ebecryl 8800 (urethane oligomer manufactured by Daicel UCB) 3.5 parts Irgacure 907 (photo radical polymerization initiator manufactured by Ciba Specialty Chemicals) 3.0 parts Irgacure 819 (photo radical polymerization initiator manufactured by Ciba Specialty Chemicals) 5.0 parts (Comparative Example 3)

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
Pigment dispersion A 11.4 parts 2-phenoxyethyl acrylate 40.0 parts BYK-331 (silicon resin manufactured by BYK Chemie) 0.1 part Tripropylene glycol diacrylate 17.7 parts Ethoxylated trimethylo- 20.0 parts of lepropane triacrylate / urethane bond-containing monomer obtained in Synthesis Example 1 3.8 parts / Irgacure 907 (photo radical polymerization initiator manufactured by Ciba Specialty Chemicals) 4.0 parts / Irgacure 819 (Ciba Specialty Chemicals) 4.0 parts (Comparative Example 4)

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
Pigment dispersion B 8.6 parts, 2-phenoxyethyl acrylate 11.8 parts, propoxylated neopentyl glycol diacrylate 21.0 parts, BYK-361N (acrylic resin manufactured by BYK Chemie) 0.1 part, synthesis example 50.5 parts of the urethane bond-containing monomer obtained in Step 2 • Irgacure 907 (Ciba Specialty Chemicals photo radical polymerization initiator) 3.0 parts • Irgacure 819 (Ciba Specialty Chemicals photo radical polymerization initiator) 5.0 Part (Comparative Example 5)

The pigment dispersion was converted into an ink with the following formulation to obtain an inkjet ink.
-Pigment dispersion C 16.5 parts-Isobornyl acrylate 2.5 parts-Tripropylene glycol diacrylate 18.0 parts-Ethoxylated trimethylolpropane triacrylate 17.0 parts-BYK-UV3510 (Sold by BYK Chemie, Silicon) Resin) 0.1 part ・ Ebecryl 270 (urethane oligomer made by Daicel UCB) 9.5 parts ・ Irgacure 907 (photo radical polymerization initiator made by Ciba Specialty Chemicals) 3.0 parts ・ Irgacure 819 (made by Ciba Specialty Chemicals) Polymerization initiator) 5.0 parts

The inkjet inks obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were printed on a polyvinyl chloride sheet with a UVIJ printer, the printed surface was cross-cut, and a peel test was performed with a cellophane tape to evaluate adhesion.

As a result, the inks of Examples 1 to 4 were not peeled off from the polyvinyl chloride sheet and had good adhesion, but the inks of Comparative Examples 1 to 3 were peeled off from the polyvinyl chloride. The ink was not UV cured, and the ink of Comparative Example 5 had a high viscosity and could not be printed.

Claims (5)

In the active energy ray-curable inkjet ink comprising a pigment, a pigment dispersant, and a monomer, the monomer includes a urethane bond-containing monomer having one urethane bond and an ethylenic double bond in the molecule, and the urethane bond-containing monomer Is an active energy ray-curable ink-jet ink containing 5 to 50% by weight in all monomers. 2. The active energy ray-curable inkjet ink according to claim 1, wherein the number average molecular weight of the urethane bond-containing monomer is 200 or more and 1,000 or less. The active energy ray-curable inkjet ink according to claim 1 or 2, wherein the urethane bond-containing monomer has a viscosity at 25 ° C of 1 to 2000 mPa · s. 4. The active energy ray-curable monomer according to claim 1, wherein the urethane bond-containing monomer is produced from an isocyanatoalkyl (meth) acrylate and a compound having one hydroxyl group and an ethylenic double bond. Inkjet ink. A printed matter obtained by forming an image on a substrate with the active energy ray-curable inkjet ink according to claim 1 and then curing the ink with an active energy ray.