JP5621209B2 - Active energy ray curable inkjet ink - Google Patents

Description

  The present invention relates to an active energy ray-curable inkjet ink composition excellent in storage stability.

  Conventionally, active energy ray-curable inks have been used for offset printing and silk screen printing, but the cost per color can be reduced by ejecting the required amount of ink droplets when needed during printing. In recent years, demand for active energy ray-curable inks for ink jet printing has been increasing from the point that on-demand printing is possible without requiring a plate. Active energy ray curable inks for inkjet printing include ultraviolet curable ink jet inks that are cured with ultraviolet rays. Compared to conventional water-based or solvent-based non-curable inkjet inks, environmentally friendly by reducing volatile solvents. In recent years, a patent has been disclosed (see Patent Documents 1 and 2) in that it can be printed on a substrate having quick drying properties, odor reduction, and no ink absorbability, and has high substrate selectivity.

  Ink-jet ink is also characterized in that the viscosity has a great influence on the printing stability and the resulting image quality compared to other printing system inks such as gravure and offset. However, the conventional active energy ray-curable ink-jet ink has a problem in that radicals are generated by some energy such as temperature and impact and the polymerization reaction proceeds, so that the viscosity of the ink easily changes, resulting in poor printing and poor image quality. It was.

JP-A-6-200204 Special Table 2000-504778

  An object of the present invention is to provide an active energy ray-curable ink-jet ink excellent in printing stability and image quality stability.

As a result of intensive studies, the present inventors have found that, in an active energy ray-curable ink-jet ink comprising a polymerizable monomer and a photoradical polymerization initiator, the ink set under a condition with a viscosity change rate is a printing stability and It was found that the image quality is excellent.
That is, the first invention is an active energy ray-curable inkjet ink composition comprising a polymerizable monomer and a radical photopolymerization initiator, and the ink is stored at a 100% filling rate in a sealed container. The present invention relates to an active energy ray-curable ink jet ink composition having a viscosity change rate at 25 ° C of less than 10% after 45 days at 45 ° C.
The second invention relates to the active energy ray-curable inkjet ink composition described above, wherein the content of the radical photopolymerization initiator is 2 to 20% by weight of the total ink.

In the third invention, the radical photopolymerization initiator is [compound 1 = 2,4,6-trimethylbenzoyldiphenylphosphine oxide], [compound 2 = 4-benzoyl-4′-methyldiphenyl sulfide], [compound 3]. = 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one], the active energy ray-curable inkjet ink composition as described above, .
The fourth invention relates to [compound 4 = 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1], [compound 5 = bis (2,4,6-trimethylbenzoyl) phenyl. Phosphine oxide] and [Compound 6 = Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone)] are combined to give a total of 5 of the total ink. The active energy ray-curable inkjet ink composition as described above, which is contained in an amount of not more than% by weight.

5th invention contains 3 weight% or less of the radical photopolymerization initiator shown by [compound 4] and [compound 5] in total 3 weight% or less, The activity in any one of Claims 1-4 characterized by the above-mentioned The present invention relates to an energy ray curable inkjet ink composition.
The sixth invention relates to the active energy ray-curable inkjet ink composition described above, which does not contain the photoradical polymerization initiator represented by [Compound 5].
The seventh invention relates to the active energy ray-curable inkjet ink composition as described above, wherein the monofunctional monomer is contained in the polymerizable monomer in an amount of 30% by weight or more.
The eighth invention relates to the active energy ray-curable inkjet ink composition as described above, wherein the monofunctional monomer contains 2-phenoxyethyl acrylate.
The ninth invention relates to the active energy ray-curable inkjet ink composition as described above, wherein the monofunctional monomer contains N-vinyl-2-caprolactam.
A tenth invention relates to the above active energy ray-curable inkjet ink composition comprising a pigment and a pigment dispersant.
The eleventh invention relates to a printed matter obtained by forming an image on a substrate with the active energy ray-curable inkjet ink described above and then curing the ink with an active energy ray.

  According to the present invention, an active energy ray-curable ink-jet ink having excellent printing stability and image quality stability can be provided.

  Hereinafter, the present invention will be described in detail.

[Active energy ray-curable inkjet ink]
The active energy ray-curable ink jet ink of the present invention is an ink jet ink that causes a radical polymerization reaction due to the influence of the electron orbit of the ink composition upon irradiation with active energy rays. As an active energy ray, an electron beam, an ultraviolet ray, an infrared ray or the like affects an electron orbit of an irradiated object and shows an energy ray that can trigger a radical polymerization reaction, but if it is an energy ray that induces a polymerization reaction, It is not limited to this.
Below, an ink composition is demonstrated in detail.

[Polymerizable monomer]
The polymerizable monomer in the present invention is an active energy ray curing reaction component, and specifically represents a molecule having an ethylenically unsaturated double bond. The polymerizable monomer contains a monofunctional and / or polyfunctional polymerizable monomer, and the constituent ratio can be set as necessary.

  Specific examples of the monofunctional monomer used in the present invention include cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, methylphenoxyethyl (meth) acrylate, 4-t-butylcyclohexyl (meth) ) Acrylate, caprolactone modified tetrahydrofurfuryl (meth) acrylate, tribromophenyl (meth) acrylate, ethoxylated tribromophenyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate (or its ethylene oxide and / or propylene oxide) Addition monomer), acryloylmorpholine, isobornyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, N-vinylcaprolactam N-vinylpyrrolidone, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4 -Hydroxybutyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isooctyl (meth) acrylate, 2-methoxy Ethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate Relate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, dipropylene glycol (meth) acrylate, β-carboxylethyl (meth) acrylate, ethyl diglycol (meth) acrylate, Trimethylolpropane formal mono (meth) acrylate, imide (meth) acrylate, isoamyl (meth) acrylate, ethoxylated succinic acid (meth) acrylate, trifluoroethyl (meth) acrylate, ω-carboxypolycaprolactone mono (meth) acrylate, Although N-vinylformamide can be mentioned, it is not limited to this.

  Furthermore, among these, as monofunctional monomers having high inkjet suitability, cyclohexyl acrylate, methylphenoxyethyl acrylate, 2-phenoxyethyl acrylate (or its ethylene oxide / propylene oxide addition monomer), acryloylmorpholine, isobornyl acrylate, N- Vinyl caprolactam, N-vinyl pyrrolidone, 2-hydroxy-3-phenoxypropyl acrylate, 1,4-cyclohexanedimethanol monoacrylate, isooctyl acrylate, and lauryl acrylate can be more preferably used.

  Ink jet aptitude is aptitude as an active energy ray-curable ink jet ink, and specifically means discharge stability in an ink jet discharge device and curability when irradiated with active energy rays. Rheological properties such as the viscosity and surface tension of the monomer affect the ejection stability, and structural properties such as the number of functional groups and molecular weight of the monomer affect the curability.

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

Further, as the polyfunctional monomer, specifically, dimethylol-tricyclodecane di (meth) acrylate, propoxylated bisphenol A di (meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, cyclohexanedimethanol di (meth) ) Acrylate, dimethylol dicyclopentane di (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, tri (2-hydroxyethylisocyanurate) tri (meth) acrylate, tri (meth) allyl isocyanurate, ethylene glycol Di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethoxylated 1,6-hexanedio Rudi (meth) acrylate, neopentyl glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tetraethylene glycol Di (meth) acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, caprolactone-modified hydroxypivalate ester neopentyl glycol di (Meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate hydroxypivalate, etho Silylated phosphate tri (meth) acrylate, ethoxylated tripropylene glycol di (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, stearic acid modified pentaerythritol di (meth) acrylate, pentaerythritol tri (meta ) Acrylate, tetramethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, caprolactone modified trimethylolpropane tri (meth) acrylate, propoxylate glyceryl tri (meth) acrylate, tetra Methylolmethane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra ( (Meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, neopentyl glycol oligo (meta) ) Acrylate, 1,4-butanediol oligo (meth) acrylate, 1,6-hexanediol oligo (meth) acrylate, trimethylolpropane oligo (meth) acrylate, pentaerythritol oligo (meth) acrylate, ethoxylated neopentyl glycol di (Meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate Ethoxylated trimethylolpropane tri (meth) acrylate, there may be mentioned propoxylated trimethylolpropane tri (meth) acrylate, but is not limited thereto.
Among these, dimethylol-tricyclodecane diacrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, propoxylated bisphenol A di (meth) acrylate, ethoxylated bisphenol A di (meta) ) Acrylate can be used more suitably.

  These monofunctional and polyfunctional monomers may be used alone or in combination of two or more as required. In general, a polyfunctional monomer has a higher viscosity than a monofunctional monomer. Therefore, if the ratio of the polyfunctional monomer is too large, the viscosity of the ink is increased and the ejection stability may be lowered. Therefore, it is preferable to contain a monofunctional monomer in the polymerizable monomer in an amount of 30% by weight or more.

  In addition to the above, what is called an oligomer or a prepolymer may be used for the inkjet ink of the present invention. 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.

[Photo radical polymerization initiator]
The radical photopolymerization initiator of the present invention is preferably a molecular cleavage type or a hydrogen abstraction type. As a specific example of the molecular cleavage type,
Benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide,
Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-benzyl-2-dimethylamino-4′-morpholinobutylphenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) -Butan-1-one, bis (2,4,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 1,2-octanedione 1- (4- (phenylthio) -2- ( O-benzoyloxime)), 1-hydroxycyclohexyl phenyl ketone, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone), 2-hydroxy-2-methyl-1- Phenylpropan-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl 1-propan-1-one, 2-hydroxy-1- (4- (4- (2-hydroxy-2-methylpropionyl) benzyl) phenyl) -2-methylpropan-1-one, benzoin ethyl ether, benzyldimethyl ketal 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, and the like Preferably used.

As a specific example of the hydrogen extraction type,
Benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4′-methyl-diphenyl sulfide, and the like are preferably used.
Moreover, the sclerosis | hardenability and viscosity stability of inkjet ink can be controlled by selecting the radical photopolymerization initiator to be used. For example,
2,4,6-trimethylbenzoyldiphenylphosphine oxide,
2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one,
4-benzoyl-4′-methyl-diphenyl sulfide,
Is used, it is possible to obtain an ink having good ultraviolet curability and hardly causing a change in viscosity. on the other hand,
Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide,
2-benzyl-2-dimethylamino-4′-morpholinobutylphenone,
Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone),
Is used, it is possible to obtain an ink that has very good UV curability but relatively easily changes in viscosity.

Thus, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide,
2-benzyl-2-dimethylamino-4′-morpholinobutylphenone, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone),
The total of the three components is preferably 5% by weight or less of the total ink,
The total of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and 2-benzyl-2-dimethylamino-4′-morpholinobutylphenone is preferably 3% by weight or less of the total ink, It is particularly preferred not to contain (2,4,6-trimethylbenzoyl) phenylphosphine oxide.

  Moreover, you may use a sensitizer together with the said radical photopolymerization initiator. Examples of sensitizers include trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N, N-dimethylbenzylamine and 4,4 ′. An amine that does not cause an addition reaction with the polymerizable component, such as 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 is used in the range of 2 to 20% by weight, preferably 5 to 19% by weight, more preferably 10 to 18% by weight, based on the total amount of the viscosity-change inkjet ink. If the amount is too large, precipitation or bleed is caused.

[Pigment]
The inkjet ink shown by this invention shows the liquid printed or coated on the base-material surface. This ink can be used as a coating application when it does not contain a coloring component, and can be used as a material for displaying graphics, characters, photographs, etc. when it contains a coloring component. Conventionally, dyes and pigments are widely used as the coloring component, but pigments are often used particularly from the viewpoint of weather resistance. As a pigment component,
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 L, # 44, # 40, # 33, # 332, # 30, # 25, # 20, # 10, # 5, CF9, # 95, # 260 "
And so on. Further, in the present invention, yellow, magenta, cyan ink, or other colors such as white can be used, and pigments used in inks generally used in printing applications and paint applications can be used, such as color developability and light resistance. Can be selected according to the required use.
The ratio of the pigment to the total ink is 1 to 15 parts by weight for organic pigments such as yellow, magenta, cyan and black with respect to 100 parts by weight of ink. It is preferable to mix in an arbitrary ratio of 5 to 40 parts by weight.

  When a pigment is contained, it is preferable to add a pigment dispersant in order to improve the dispersibility of the pigment and the storage stability of the ink. There are various types of pigment dispersants such as a high molecular type dispersant and a low molecular type dispersant. These can be selected according to dispersibility, for example, hydroxyl group-containing carboxylic acid ester, salt of long chain polyaminoamide and high molecular weight acid ester, salt of high molecular weight polycarboxylic acid, long chain polyaminoamide and polar acid ester. Salt, high molecular weight unsaturated acid ester, polymer copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalenesulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxy Ethylene alkyl phosphate ester, polyoxyethylene nonylphenyl ether, stearylamine acetate and the like 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) ", Kyoeisha Chemical Co., Ltd." Floren TG-710 (urethane oligomer), "Flownon “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 pigment dispersant is preferably contained in the composition in an amount of 0.1 to 10% by weight. Further, 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.

[Additive]
In the ink-jet ink of the present invention, various additives such as a plasticizer, a surface tension adjuster, an ultraviolet ray inhibitor, a slipping agent, an antiblocking agent, a light stabilizer, and an antioxidant can be used.

  As a surface tension adjusting agent for improving the wettability to the substrate, the slipperiness of the printed film, and the blocking property, “BYK-300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 340, 344, 370, 375, 377, 350, 352, 354, 355, 356, 358N, 361N, 357, 390, 392, UV3500, UV3510, UV3570 “Tegorad-2100, 2200, 2250, 2500, 2700” and the like manufactured by the company are listed. These surface conditioners are preferably contained in the composition in an amount of 0.001 to 1% by weight, and may be used alone or in combination of two or more as required.

[ink]
The active energy ray-curable ink-jet ink is produced by well dispersing a pigment together with a polymerizable monomer and a pigment dispersant using a normal 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 form an image with the inkjet ink of the present invention, a method is preferred in which the ink is ejected and drawn on a substrate by an inkjet recording method and then the ink is cured by irradiation with an active energy ray such as ultraviolet rays. It is not limited to.

  When irradiating ultraviolet rays as a light source for active energy rays, for example, high-pressure mercury lamps, metal halide lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, UV-LEDs that are monochromatic light, ultraviolet lasers, and sunlight are also used. can do. 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.

[Closed container]
The airtight container used in the present invention indicates all containers used for ink storage, and those of known materials and forms can be used, but a plastic bottle with a lid, a glass bottle with a lid, and an aluminum pouch are preferably used. It is done.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these. In the examples, “parts” represents “parts by weight” and “%” represents “% by weight”.

<Viscosity change rate>
The inkjet ink was sealed in an aluminum pouch at a filling rate of 100%, and then stored in an oven maintained at 45 ° C. for 60 days. The ink viscosity before and after storage was measured using an E-type viscometer VISCOMETER TV-22 manufactured by Toki Sangyo Co., Ltd., and the rate of change relative to the viscosity before storage was determined.
<Printing stability>
The ink-jet ink was observed with a large-format UV ink-jet printer, and the printing state of the nozzle check pattern after 50 hours of continuous solid printing on a polyvinyl chloride resin sheet (MD-5 manufactured by Metamark) was observed. For print defects such as nozzle omission, flying bend or ink splatter, 1% or less was marked as ◎, 1-5% as ◯, 5-10% as △, and 10% or more as x.

<Printed product density>
For the 50-hour continuous solid print obtained above, the print density immediately after the start of printing and after 50 hours was measured at any five locations with X-rite 530 (X-rite, G-Response). The average value was obtained. The change rate of the concentration was 5% or less, ◎, 5 to 10% was ◯, 10 to 20% was Δ, and 20% or more was ×.

  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.

<Pigment dispersion A>
・ Solsperse 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 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.

<Pigment dispersion B>
・ Hostaperm Red E5B02 (Clariant quinacridone pigment) 20.0 parts ・ Solspers 24000 (Avisia pigment dispersion) 6.0 parts ・ 2-phenoxyethyl acrylate 74.0 parts

Further, Pigment Dispersion C 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.

<Pigment dispersion C>
・ YELLOW PIGMENT E4GN
(Nickel complex azo pigment manufactured by LANXESS) 20.0 parts · Solsperse 33000 (pigment dispersant manufactured by Avicia) 15.0 parts · 25.0 parts of 2-phenoxyethyl acrylate

  An ink-jet ink was obtained by using the pigment dispersion to make an ink with the following formulation.

<Inkjet ink A>
-Pigment dispersion A 11.5 parts-2-phenoxyethyl acrylate 9.1 parts-N-vinylcaprolactam 16.1 parts-Isobornyl acrylate 8.1 parts-Tripropylene glycol diacrylate 24.2 parts-Kayarad R604 (Nippon Kayaku Co., Ltd.) 16.1 parts ・ DAIDO UV-CURE APO (Daido Kasei Kogyo Co., Ltd.) 5.0 parts ・ Kayacure BMS (Nippon Kayaku Co., Ltd.) 5.0 parts ・ Irgacure 907 ( Ciba Specialty Chemicals) 5.0 parts

<Inkjet ink B>
-Pigment dispersion A 11.5 parts-2-phenoxyethyl acrylate 9.1 parts-N-vinylcaprolactam 16.1 parts-Isobornyl acrylate 8.1 parts-Tripropylene glycol diacrylate 24.2 parts-Kayarad R604 16.1 parts ・ DAIDO UV-CURE APO 4.5 parts ・ Kayacure BMS 4.5 parts ・ Irgacure 907 4.5 parts ・ Irgacure 369 (Ciba Specialty Chemicals) 1.5 parts

<Inkjet ink C>
-Pigment dispersion A 11.5 parts-2-phenoxyethyl acrylate 9.1 parts-N-vinylcaprolactam 16.1 parts-Isobornyl acrylate 8.1 parts-Tripropylene glycol diacrylate 24.2 parts-Kayarad R604 16.1 parts ・ DAIDO UV-CURE APO 4.5 parts ・ Kayacure BMS 4.5 parts ・ Irgacure 907 4.5 parts ・ Irgacure 819 (Ciba Specialty Chemicals) 1.5 parts

<Inkjet ink D>
-Pigment dispersion A 11.5 parts-2-phenoxyethyl acrylate 9.1 parts-N-vinylcaprolactam 16.1 parts-Isobornyl acrylate 8.1 parts-Tripropylene glycol diacrylate 24.2 parts-Kayarad R604 16.1 parts ・ DAIDO UV-CURE APO 4.5 parts ・ Kayacure BMS 4.5 parts ・ Irgacure 907 4.5 parts ・ ESACURE ONE (made by Lamberti) 1.5 parts

<Inkjet ink E>
Pigment dispersion A 11.5 parts 2-phenoxyethyl acrylate 10.5 parts N-vinylcaprolactam 17.5 parts Isooctyl acrylate 8.8 parts Dipropylene glycol diacrylate 26.3 parts Kayrad R551 ( Nippon Kayaku Co., Ltd.) 17.5 parts ・ DAIDO UV-CURE APO 5.0 parts ・ Irgacure 369 1.0 part ・ Irgacure 819 1.0 part ・ ESACURE ONE 1.0 part

<Inkjet ink F>
-Pigment dispersion B 18.0 parts-4.1 parts of 2-phenoxyethyl acrylate-4.4 parts of N-vinylcaprolactam-13.1 parts of isobornyl acrylate-34.9 parts of tripropylene glycol diacrylate-Kayrad R551 17.5 parts ・ Kayacure BMS 5.0 parts ・ Irgacure 369 1.0 part ・ Irgacure 819 1.0 part ・ ESACURE ONE 1.0 part

<Inkjet ink G>
-Pigment dispersion C 17.0 parts-2-phenoxyethyl acrylate 14.8 parts-Isooctyl acrylate 8.6 parts-Dipropylene glycol diacrylate 34.4 parts-Kayarad R604 17.2 parts-Irgacure 907 5.0・ Irgacure 369 1.0 part ・ Irgacure 819 1.0 part ・ ESACURE ONE 1.0 part

<Inkjet ink H>
-Pigment dispersion A 11.5 parts-2-phenoxyethyl acrylate 6.1 parts-N-vinylcaprolactam 13.1 parts-Isoboronyl acrylate 6.6 parts-Tripropylene glycol diacrylate 19.7 parts-Kayarad R604 13.1 parts ・ DAIDO UV-CURE APO 5.0 parts ・ Kayacure BMS 5.0 parts ・ Irgacure 907 5.0 parts ・ Irgacure 369 5.0 parts ・ Irgacure 819 5.0 parts ・ ESACURE ONE 5.0 parts

<Inkjet ink I>
-Pigment dispersion A 11.5 parts-2-phenoxyethyl acrylate 9.1 parts-N-vinylcaprolactam 16.1 parts-Isobornyl acrylate 8.1 parts-Tripropylene glycol diacrylate 24.2 parts-Kayarad R604 16.1 parts ・ Irgacure 369 5.0 parts ・ Irgacure 819 5.0 parts ・ ESACURE ONE 5.0 parts

<Inkjet ink J>
Pigment dispersion A 11.5 parts 2-phenoxyethyl acrylate 10.5 parts N-vinylcaprolactam 17.5 parts Isoboronyl acrylate 8.8 parts Tripropylene glycol diacrylate 26.3 parts Kayrad R604 17.5 parts ・ Irgacure 369 8.0 parts

<Inkjet ink K>
Pigment dispersion A 11.5 parts 2-phenoxyethyl acrylate 10.5 parts N-vinylcaprolactam 17.5 parts Isoboronyl acrylate 8.8 parts Tripropylene glycol diacrylate 26.3 parts Kayrad R604 17.5 parts Irgacure 819 8.0 parts

<Inkjet ink L>
Pigment dispersion A 11.5 parts 2-phenoxyethyl acrylate 10.5 parts N-vinylcaprolactam 17.5 parts Isoboronyl acrylate 8.8 parts Tripropylene glycol diacrylate 26.3 parts Kayrad R604 17.5 parts-ESACURE ONE 8.0 parts

[Examples 1-7]
Using the inkjet inks A to G, the rate of change in viscosity, printing stability, and printed matter density were evaluated. The obtained results are shown in Table 1.
In addition,
Compound 1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide Compound 2: 4-benzoyl-4'-methyldiphenyl sulfide Compound 3: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane- 1-one compound 4: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1
Compound 5: Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide Compound 6: Oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone

[Comparative Examples 1-5]
Using the inkjet inks H to L, the rate of change in viscosity, printing stability, and printed matter density were evaluated. The obtained results are shown in Table 1.

Claims (9)

A polymerizable monomer, at least 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 4-benzoyl-4'-methyldiphenyl sulfide, and 2-methyl-1- (4-methylthiophenyl) as a radical photopolymerization initiator 2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,4,6-trimethylbenzoyl) Active energy in which the total content of phenylphosphine oxide and oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) is 0% by weight to 5% by weight of the total ink It is a line curable ink jet ink composition, and when the ink is stored at 100% filling rate in a sealed container The active energy ray curable ink-jet ink composition, wherein the viscosity change rate at 25 ° C. After 5 ° C. 60 days is less than 10%. 2. The active energy ray-curable inkjet ink composition according to claim 1, wherein the content of the radical photopolymerization initiator is 2 to 20% by weight of the whole ink. As the radical photopolymerization initiator, the total content of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide is The active energy ray-curable inkjet ink composition according to claim 1, wherein the composition is contained in an amount of 0% by weight to 3% by weight of the total ink. The active energy ray-curable inkjet ink composition according to claim 1, which does not contain bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide as a radical photopolymerization initiator. The active energy ray-curable inkjet ink composition according to claim 1, wherein the monofunctional monomer is contained in the polymerizable monomer in an amount of 30% by weight or more. The active energy ray-curable inkjet ink composition according to any one of claims 1 to 5, comprising 2-phenoxyethyl acrylate as a monofunctional monomer. The active energy ray-curable inkjet ink composition according to claim 1, wherein N-vinyl-2-caprolactam is contained as a monofunctional monomer. The active energy ray-curable ink-jet ink composition according to claim 1, comprising a pigment and a pigment dispersant. A printed matter obtained by forming an image on the substrate with the active energy ray-curable inkjet ink according to claim 1 and then curing the ink with an active energy ray.