JP5659655B2 - Active energy ray-curable inkjet ink composition, inkjet ink, and inkjet recording method - Google Patents

Description

  The present invention relates to an active energy ray-curable inkjet ink composition having a novel configuration, an inkjet ink using the same, and an inkjet recording method.

  In recent years, the inkjet recording method has been used in various printing fields such as photographs, various printing, marking, and special printing such as color filters from the viewpoint that an image can be easily and inexpensively created.

  As an inkjet ink used in such an inkjet recording system, an aqueous inkjet ink containing water as a main solvent, a non-volatile solvent that does not volatilize at room temperature, an oil-based inkjet ink that does not substantially contain water, and volatilizes at room temperature. Non-water-based inkjet ink that contains mainly solvent and contains substantially no water, hot-melt ink that heats and melts solid ink at room temperature, and active energy ray-curable inkjet that cures with actinic rays such as ultraviolet rays after printing There are various ink-jet inks such as inks, and they have been properly used depending on the application. Among them, the active energy ray-curable ink-jet ink is fast-curing and can print on a wide variety of recording media. Water-based ink with a large drying load and limited recording media Ettoinku or oil-based inkjet ink, has attracted attention as a next-generation inkjet ink to replace the non-aqueous inkjet ink, a large expected that expanding applications.

  Conventionally, active energy ray-curable inkjet inks are mainly classified into radical polymerization type and cationic polymerization type inkjet inks. Radical polymerization type ink-jet inks are widely researched and developed and put into practical use because of their wide choice of materials and high degree of freedom in ink design. On the other hand, since the cationic polymerization type ink-jet ink is not affected by the inhibition of polymerization by oxygen, it has excellent curability of small droplets and curability with a low energy light source, and a relatively highly flexible cured film is formed. There is an advantage that can be obtained.

  However, in the case of using either radical polymerization type or cationic polymerization type inkjet ink, there is an aspect that is inferior in terms of image quality as compared with aqueous inkjet ink and non-aqueous inkjet ink. For example, in an ink jet printer that forms an image by scanning a plurality of times, after printing ink jet ink and irradiating active energy rays, the print dots are aggregated until they are completely cured, resulting in a mottled color. In so-called mottling or single-pass inkjet printers that perform image formation in a single pass, the printed ink droplets agglomerate between printing and irradiation with active energy rays. There is a problem that the phenomenon of color loss in streaks occurs. In addition, there is a problem that wrinkles are generated due to curing shrinkage and glossiness does not appear. In addition, since the polymerizable compound is polymerized to have a high molecular weight during the curing process, the compatibility of components such as a polymerization initiator is reduced, and precipitation occurs in the image, thereby reducing the glossiness. is there.

  Such a problem can be seen in both radical polymerization ink jet ink and cation polymerization ink jet ink. In particular, lack of glossiness is a problem that is prominent in radical polymerization ink jet ink. It was.

  In response to the above problems, a technique for improving image quality by adjusting the surface energy of a cured film and the surface tension of an ink-jet ink by using a polymerizable compound having a hydroxyl group or an amide group in a radical polymerization ink-jet ink is disclosed. (For example, refer to Patent Document 1). However, the method described in Patent Document 1 is still insufficient for obtaining an image with mottle, stripes, and gloss.

JP 2010-1332739 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to improve the mottling resistance of an ink jet printer that forms an image by scanning a plurality of times and to use a single pass ink jet printer that forms an image in one pass. It is an object to provide an active energy ray-curable inkjet ink composition capable of improving the streak resistance and obtaining an image having excellent gloss, an inkjet ink using the same, and an inkjet recording method.

  The above object of the present invention is achieved by the following configurations.

  1. An active energy ray-curable inkjet ink composition comprising a polymerizable compound, a photopolymerization initiator, and a β-alkoxypropionamide represented by the following general formula (1).

[Wherein R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, and R ₂ and R ₃ each represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. R ₂ and R ₃ may be the same or different. ]
2. 2. The active energy ray-curable inkjet ink composition according to 1, wherein a radical polymerizable compound is contained as the polymerizable compound, and a photo radical polymerization initiator is contained as the photo polymerization initiator.

  3. 2. The active energy ray-curable inkjet ink composition according to 1, wherein a cationic polymerizable compound is contained as the polymerizable compound and a cationic photopolymerization initiator is contained as the photopolymerization initiator.

  4). 4. An ink jet ink comprising the active energy ray-curable ink jet ink composition according to any one of items 1 to 3 and a colorant.

  5. 5. An ink jet recording method comprising: performing ink jet recording by ejecting the ink jet ink onto a recording medium using the ink jet ink described in 4 above.

  According to the present invention, improvement in mottling resistance in an ink jet printer that forms an image by scanning a plurality of times, and improvement in streak resistance in a single pass type ink jet printer that forms an image in one pass, and obtaining an image with excellent gloss An active energy ray-curable inkjet ink composition that can be used, an inkjet ink using the same, and an inkjet recording method can be provided.

It is a front view which shows an example of a structure of the principal part of the inkjet recording device used for the inkjet recording method of this invention. It is a top view which shows another example of a structure of the principal part of the inkjet recording device used for the inkjet recording method of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the present inventor contains a polymerizable compound, a photopolymerization initiator, and a β-alkoxypropionamide represented by the general formula (1). High-quality image with excellent mottling resistance and streak resistance even for recording media with low surface energy, such as coated paper and resin recording media, due to the energy ray curable inkjet ink composition. The present inventors have found that an active energy ray-curable ink-jet ink composition capable of forming an ink, an ink-jet ink using the same, and an ink-jet recording method can be realized, and the present invention has been achieved.

  That is, the present inventor found that the active energy ray-curable ink-jet ink has no surface streaks or mottling and has a high quality on a recording medium whose surface is made of resin or coated paper with poor water absorption such as printing paper. Studies have been made for the purpose of forming an image that can be printed and has excellent gloss. The recording medium having a resin surface in the present invention specifically means a resin plate such as polystyrene or acrylonitrile-butadiene-styrene copolymer (ABS resin), or a plastic film such as vinyl chloride or polyethylene terephthalate (PET). Alternatively, it is a recording medium in which these plastic films are pasted on the surface of a substrate such as paper, and the recording surface is a recording medium that hardly penetrates the inkjet ink.

  Since these recording media and coated papers made of resin have poor ink absorbency and the surface energy of the recording media is low, in an image forming method using a single-pass ink jet printer, active energy rays are irradiated after printing. In the meantime, the ink is repelled within a few microseconds to several hundred milliseconds, and the droplets are aggregated and united to cause streaks.

  In an inkjet printer that forms an image by scanning a plurality of times, the dots printed on the cured film are not sufficiently wetted and spread when cured by being irradiated with active energy rays. It is considered that a so-called Mottling phenomenon occurs in which aggregation occurs and the color becomes mottled.

  For such problems, the present invention has found that the occurrence of streaks and mottling is suppressed by adding the β-alkoxypropionamides represented by the general formula (1) according to the present invention. It is a thing.

  The mechanism is only an estimate, but for the streaks in the single-pass inkjet printer, the active energy ray-curable type of the present invention containing the β-alkoxypropionamide represented by the general formula (1) according to the present invention. It is presumed that when the ink-jet ink composition and the ink-jet ink containing the ink are printed on a recording medium having a low surface energy, the wetting and spreading of the dots is improved and the droplets are prevented from coalescing. Mottling in an inkjet printer that forms an image by scanning a plurality of times is estimated as follows. That is, the β-alkoxypropionamides represented by the general formula (1) according to the present invention improves the wetting and spreading of the dots printed on the cured film and prevents the droplets from aggregating. It is presumed that the generation of the ring is prevented.

  Furthermore, the present inventor has found that the glossiness is improved by incorporating the β-alkoxypropionamide represented by the general formula (1) according to the present invention into the active energy ray-curable inkjet ink. It was. This mechanism is estimated as follows. That is, firstly, it is presumed that the polymerizable compound reduces curing shrinkage that occurs during polymerization and prevents wrinkles that occur during curing. Second, by improving the compatibility of the polymerization initiator in the cured film, it prevents precipitation of the polymerization initiator inside the cured product and improves the transparency of the cured film, resulting in improved gloss. Estimated. This effect is exhibited in both radical polymerization ink jet ink and cationic polymerization ink jet ink. However, curing shrinkage easily occurs, and a large amount of photopolymerization initiator is added to inhibit polymerization due to oxygen during curing. In the radical polymerization ink-jet ink, the improvement effect is more favorably exhibited.

  Hereinafter, the active energy ray-curable inkjet ink composition of the present invention, the inkjet ink using the composition, and the inkjet recording method will be described in detail.

[Β-alkoxypropionamides represented by the general formula (1)]
In the general formula (1), R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, and R ₂ and R ₃ are each a hydrogen atom, or a straight chain having 1 to 4 carbon atoms or It represents a branched alkyl group, and R ₂ and R ₃ may be the same or different.

By selecting the groups defined above as R ₁ , R ₂ , and R ₃ , the solubility and penetration ability of the resin component of β-alkoxypropionamides can be maintained and the compatibility with water can be increased. it can.

R ₁ is preferably a methyl group, an ethyl group or an n-butyl group, and preferred R ₂ and R ₃ are a methyl group or an ethyl group.

  The addition amount of the β-alkoxypropionamide represented by the general formula (1) to the active energy ray-curable inkjet ink composition or inkjet ink is the total amount of the active energy ray-curable inkjet ink composition or inkjet ink. On the other hand, it is preferable that it is 1.0 mass% or more and less than 40 mass%.

  Specific examples of β-alkoxypropionamides represented by the general formula (1) are shown below.

A-1: 3-methoxy-N, N-dimethylpropionamide A-2: 3-n-butoxy-N, N-dimethylpropionamide A-3: 3-ethoxy-N, N-diethylpropionamide A-4 : 3-methoxy-N, N-diethylpropionamide A-5: 3-methoxy-N, N-monomethylmonoethylpropionamide A-6: 3-methoxy-N, N-di-n-propylpropionamide A- 7: 3-methoxy-N, N-di-n-butylpropionamide A-8: 3-methoxy-N, N-di-n-butylpropionamide A-9: 3-ethoxy-N, N-dimethylpropion Amide A-10: 3-Ethoxy-N, N-monomethylmonoethylpropionamide A-11: 3-Ethoxy-N, N-di-n-propylpropionamide A- 2: 3-Ethoxy-N, N-di-n-butylpropionamide A-13: 3-n-butoxy-N, N-diethylpropionamide A-14: 3-n-butoxy-N, N-monomethylmono Ethylpropionamide A-15: 3-n-butoxy-N, N-di-n-propylpropionamide A-16: 3-n-butoxy-N, N-di-n-butylpropionamide A-17: 3 -N-propoxy-N, N-dimethylpropionamide A-18: 3-n-propoxy-N, N-diethylpropionamide A-19: 3-n-propoxy-N, N-monomethylmonoethylpropionamide A- 20: 3-n-propoxy-N, N-di-n-propylpropionamide A-21: 3-n-propoxy-N, N-di-n-butylpropionamide -22: 3-iso-propoxy-N, N-dimethylpropionamide A-23: 3-iso-propoxy-N, N-diethylpropionamide A-24: 3-1 so-propoxy-N, N-monomethylmonoethyl Propionamide A-25: 3-iso-propoxy-N, N-di-n-propylpropionamide A-26: 3-iso-propoxy-N, N-di-n-butylpropionamide A-27: 3- tert-Butoxy-N, N-dimethylpropionamide A-28: 3-tert-butoxy-N, N-diethylpropionamide A-29: 3-tert-butoxy-N, N-monomethylmonoethylpropionamide A-30 : 3-tert-butoxy-N, N-di-n-propylpropionamide A-31: 3-tert -Butoxy-N, N-di-n-butylpropionamide A-32: 3-hexyloxy-N, N-dimethylpropionamide A-33: 3-hexyloxy-N, N-diethylpropionamide Specific production methods of β-alkoxypropionamides represented by the general formula (1) are described in, for example, JP2009-185079A and International Publication No. 2008/102615, etc. It is commercially available from Idemitsu Kosan Co., Ltd. under the product name.

[Polymerizable compound, photopolymerization initiator]
<Radically polymerizable compound>
Examples of the radical polymerizable compound applicable to the present invention include what are called prepolymers, oligomers, and the like. Specifically, N-vinylcaprolactam, N-vinylformamide, ethylene glycol di (meth) acrylate, Diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethoxylated 1,6-hexanediol diacrylate, neopentyl glycol di (meth) acrylate, ethoxylated neo Pentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol diacrylate, 1,4-butanediol di ( ) Acrylate, 1,9-nonanediol diacrylate, tetraethylene glycol diacrylate, 2-n-butyl-2-ethyl-1,3-propanediol diacrylate, dimethylol-tricyclodecane diacrylate, neopentyl hydroxypivalate 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, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentae Thritol triacrylate, tetramethylolpropane triacrylate, tetramethylolmethane 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, dipentaerythritol hexaacrylate, neopentyl glycol oligoacrylate, 1,4-butanediol oligoacrylate 1,6 -Hexanediol oligoacrylate, trimethylolpropane oligoacrylate, pentaerythritol oligoacrylate, urethane acrylate, epoxy acrylate, polyester acrylate, 2-phenoxyethyl acrylate, acryloylmorpholine, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxy Butyl acrylate, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, isobornyl acrylate, cyclohexyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl Acrylate, benzyl alcohol Relate, ethoxy ethoxyethyl acrylate, butoxyethyl acrylate, ethoxy diethylene glycol acrylate, methoxy dipropylene glycol acrylate, methyl phenoxyethyl acrylate, dipropylene glycol acrylate. These compounds may be used alone or in combination of two or more as required.

<Photoradical polymerization initiator>
As a radical photopolymerization initiator applicable to the present invention, 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.

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

  The radical photopolymerization initiator and the sensitizer are in the range of 0.1 to 20% by mass, preferably 4 to 12% by mass, based on the total mass of the active energy ray-curable inkjet ink composition.

<Cationically polymerizable compound>
As a cationically polymerizable compound applicable to the present invention, any compound having a generally known cationically polymerizable group can be used regardless of the type of monomer, oligomer or polymer. Examples of the cationic polymerizable compound include the compounds exemplified below, but the present invention is not limited to these, and any known cationic polymerizable compound can be used without any problem.

  As the cationically polymerizable compound, a known cationically polymerizable compound is used, and in addition to styrene derivatives and vinyl ethers, oxirane, oxetane, tetrahydrofuran, lactam, lactone, and the like are used. Of these, oxirane, oxetane, vinyl ether or styrene derivatives are preferably used, and oxirane and oxetane are particularly preferred.

  Any known epoxy compound can be used in combination as the compound having an oxirane group.

  Examples of monofunctional epoxides used in the present invention include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1 , 3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3- Examples include vinylcyclohexene oxide.

  Examples of polyfunctional epoxides include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl. Ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, 2 -(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexyl) Til) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ', 4'-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, Resin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-di Examples thereof include epoxy octane, 1,2,5,6-diepoxycyclooctane and the like.

  As the compound having an oxetane ring, any known oxetane compound as introduced in JP-A Nos. 2001-220526 and 2001-310937 can be used in combination.

  Examples of monofunctional oxetanes include oxetane compounds used in the present invention, such as 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, and (3-ethyl-3 -Oxetanylmethoxy) methylbenzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [ 1- (3-ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-Ethyl-3-oxetanylmethyl) ether, 2-ethyl Hexyl (3-ethyl-3-oxetanylmethyl) ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3- Ethyl-3-oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanyl) Methyl) ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl) Ru-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3- Oxetanylmethyl) ether, pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, and the like. .

  Examples of the polyfunctional oxetane include 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis. -(3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1, 3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, tri Ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl) -3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3- Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3 -Oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl) 3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis ( 3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropanetetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis ( 3-ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3-ethyl) And polyfunctional oxetanes such as ru-3-oxetanylmethyl) ether and EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether.

  Any known vinyl ether compound can be used in combination as the compound having a vinyl ether group.

  Examples of monofunctional vinyl ethers used in the present invention include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, Cyclohexylmethyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether , Methoxy polyethylene Recall vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, Examples include chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

  Examples of polyfunctional vinyl ethers include, for example, ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide. Divinyl ethers such as divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hex Vinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide-added penta And polyfunctional vinyl ethers such as erythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.

<Photocationic polymerization initiator>
As the photocationic polymerization initiator applicable to the present invention, all known light published in “Applications and Markets of UV / EB Curing Technology” (CMC Publishing Co., Ltd., edited by Yoneho Tabata / Raddotech Research Association). An initiator can be used.

  In the present invention, it is preferable to use a photoacid generator as the photocationic polymerization initiator. As the photoacid generator, for example, a chemically amplified photoresist or a compound used for photocationic polymerization is used (edited by Organic Electronics Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), 187. To page 192). Examples of compounds suitable for the present invention are listed below.

First, diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, SbF 6 -, CF 3 SO 3 - and salts be able to.

  Specific examples of onium compounds that can be used in the present invention are shown below.

  Secondly, sulfonated substances that generate sulfonic acid can be mentioned, and specific compounds thereof are exemplified below.

  Thirdly, halides that generate hydrogen halide can also be used, and specific compounds thereof are exemplified below.

  Fourthly, an iron allene complex can be mentioned.

  In particular, in the active energy ray-curable inkjet ink composition of the present invention, the photoacid generator is preferably a compound containing a triarylsulfonium salt.

  The photoacid generator is preferably contained at a ratio of 0.2 to 20 parts by mass with respect to 100 parts by mass of the cationic polymerizable compound.

  If the content of the photoacid generator is less than 0.2 parts by mass, it is difficult to obtain a cured product, and even if the content exceeds 20 parts by mass, there is no further effect of improving curability.

  These photoacid generators can be used alone or in combination of two or more.

[Colorant]
When coloring the inkjet ink of this invention, it is preferable to use a pigment as a coloring agent. As the pigment, colorless inorganic pigments such as carbon black, titanium oxide, calcium carbonate, or colored organic pigments 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 ritole red, heliobordeaux, pigment scarlet, and permanent red 2B; alizarin, indanthrone, thio Derivatives from vat dyes such as indigo 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 Isoindolinone organic pigments such as yellow and isoindolinone orange; Pyranthrone organic pigments such as pyranthrone red and pyranthrone orange; Thioindigo Machine pigments, condensed azo organic pigments, benzimidazolone organic pigments, quinophthalone organic pigments such as quinophthalone yellow; isoindoline organic pigments such as isoindoline yellow; other pigments such as flavanthron yellow, acylamide yellow, nickel Azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like can be mentioned.

  Organic pigments are exemplified below by color index (CI) numbers.

C. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 109, 110, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185,
C. I. Pigment Orange 16, 36, 43, 51, 55, 59, 61,
C. I. 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,
C. I. Pigment violet 19, 23, 29, 30, 37, 40, 50,
C. I. 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,
Among the above pigments, quinacridone-based, phthalocyanine-based, benzimidazolone-based, isoindolinone-based, condensed azo-based, quinophthalone-based, and isoindoline-based organic pigments are preferable because of their excellent light resistance.

  The organic pigment is preferably fine particles having an average particle diameter in the ink of 10 to 150 nm as measured by laser scattering. When the average particle size of the pigment is less than 10 nm, the light resistance is lowered due to the small particle size, and when it exceeds 150 nm, it is difficult to maintain stable dispersion, and the precipitation of the pigment is likely to occur. Stability is lowered, and a problem that minute mist called satellite occurs. However, in the case of titanium oxide, the average particle diameter is 150 to 300 nm, preferably 180 to 250 nm, in order to provide whiteness and concealment.

  In addition, it is preferable that coarse particles are removed by sufficient dispersion or filtration so that the maximum particle size of the pigment in the ink does not exceed 1.0 μm. When coarse particles are present, the ejection stability tends to be lowered.

  The organic pigment can be refined by the following method. That is, a mixture composed of at least three components of an organic pigment, a water-soluble inorganic salt of 3 mass times or more of the organic pigment, and a water-soluble solvent is made into a clay, and is kneaded strongly with a kneader or the like to be refined, and then poured into water. Stir with a high speed mixer or the like to form a slurry. Next, filtration and washing of the slurry are repeated, and the water-soluble inorganic salt and the water-soluble solvent are removed by aqueous treatment. 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 to 20 times the mass of the organic pigment, but after the dispersion treatment, chlorine ions (halogen ions) are washed with water in order to achieve the halogen ion content defined in the present invention. Perform the operation to remove. If the amount of the inorganic salt is less than 3 times by mass, a treated pigment having a desired size cannot be obtained, and if it is more than 20 times by mass, the washing process in the subsequent step is enormous, Processing amount is reduced.

  The water-soluble solvent is not particularly limited as long as it is a solvent that can be used for making an appropriate clay state of an organic pigment and a water-soluble inorganic salt used as a crushing aid and performing sufficient crushing efficiently, and is soluble in water. However, since the temperature rises during kneading and the solvent easily evaporates, a high boiling point solvent having a boiling point of 120 to 250 ° C. is preferable from the viewpoint of safety. As water-soluble solvents, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (i-pentyloxy) 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 addition, in order to ensure the dispersion stability of the pigment, surface treatment by a known technique such as acidic treatment or basic treatment, synergist, various coupling agents in order to promote adsorption with the pigment dispersant on the surface thereof. Is preferred.

  In order to obtain a sufficient concentration and sufficient light resistance, the pigment is in the range of 1.5 to 8% by mass in the case of a color excluding white in the inkjet ink, and in the range of 10 to 30% by mass in the case of a white ink using titanium oxide. It is preferable that it is contained.

(Pigment dispersant)
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 nonyl Examples thereof include phenyl ether, stearylamine acetate, and pigment derivatives.

  Specific examples include “Anti-Terra-U (polyaminoamide phosphate)”, “Anti-Terra-203 / 204 (high molecular weight polycarboxylate)” manufactured by BYK Chemie, “Disperbyk-101 (polyaminoamide phosphate) Salt (acid ester), 107 (hydroxyl group-containing carboxylic acid ester), 110 (copolymer containing 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 acid polycarboxylic acid) And silicone) ”,“ Lactimon (long chain amine and unsaturated acid polycarboxylic acid) Recone) "and the like.

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

  Furthermore, “Demol RN, N (Naphthalenesulfonic acid formalin condensate sodium salt), MS, C, SN-B (aromatic sulfonic acid formalin condensate sodium salt), EP”, “Homogenol L-18” manufactured by Kao Corporation. (Polycarboxylic acid type polymer) "," Emulgen 920, 930, 931, 935, 950, 985 (polyoxyethylene nonyl phenyl ether) "," Acetamine 24 (coconut amine acetate), 86 (stearyl amine acetate) "; “Solspers 5000 (phthalocyanine ammonium salt type), 13240, 13940 (polyesteramine type), 17000 (fatty acid amine type), 24000, 32000, 7000” manufactured by Zeneca Corporation; “Nikkor T106 (polyoxyethylene sorbitan) manufactured by Nikko Chemical Co., Ltd.” mono Rate), MYS-IEX (polyoxyethylene monostearate), Hexagline4-0 (hexaglyceryl ruthenate Huwei Rate) ", manufactured by Ajinomoto Fine-Techno Co., of AJISPER 821,822,824, and the like.

  These pigment dispersants are contained in an amount of 5 to 70% by mass, preferably 10 to 50% by mass, based on the pigment 100. If it is less than 5%, it may be difficult to obtain dispersion stability, and if it is more than 70%, ejection stability may be deteriorated.

  Furthermore, these pigment dispersants preferably have a solubility of 5% by mass or more with respect to the whole cationic polymerizable compound at 0 ° C. If the solubility is less than 5% by mass, when the ink is stored at a low temperature between about 0 ° C. and 10 ° C., undesired polymer gel or pigment soft agglomerates may occur, and the ink storage stability And discharge stability may deteriorate.

[Radical polymerization inhibitor]
In the active energy ray-curable inkjet ink composition or inkjet ink of the present invention, it is preferable to add a radical polymerization inhibitor from the viewpoint of storage stability. In the ink-jet ink of the present invention, radical polymerization may occur during storage due to radicals generated by the influence of heat or light. The use of a radical polymerization inhibitor in the active energy ray-curable inkjet ink composition or inkjet ink of the present invention has the effect of preventing radical polymerization that occurs during storage, but does not inhibit the curing of photocationic polymerization. This is a very preferable embodiment because it has the effect of enhancing only the storage stability of the ink over time without inhibiting the photocuring of the ink mainly composed of vinyl ether as in the present invention and having excellent curability.

  As radical polymerization inhibitors, phenolic hydroxyl group-containing compounds, methoquinone (hydroquinone monomethyl ether), hydroquinone, 4-methoxy-1-naphthol, hindered amine antioxidants, 1,1-diphenyl-2-picrylhydrazyl free radicals , N-oxide compounds, piperidine 1-oxyl free radical compounds, pyrrolidine 1-oxyl free radical compounds, N-nitrosophenylhydroxylamines, nitrogen-containing heterocyclic mercapto compounds, thioether antioxidants, hindered phenols Antioxidants, ascorbic acids, zinc sulfate, thiocyanates, thiourea derivatives, various sugars, phosphate antioxidants, nitrites, sulfites, thiosulfates, hydroxylamine derivatives, dicyandiamide and polyamines Examples thereof include polycondensates of lucylene polyamine, phenothiazine, and the like.

  Specific examples of the radical polymerization inhibitor include the following compounds.

  Examples of the phenolic compound include the following compounds: phenol, alkylphenol, such as o-, m- or p-cresol (methylphenol), 2-t-butyl-4-methylphenol, 6-t-butyl. -2,4-dimethylphenol, 2,6-di-t-butyl-4-methylphenol, 2-t-butylphenol, 4-t-butylphenol, 2,4-di-t-butylphenol, 2-methyl-4 -T-butylphenol, 4-t-butyl-2,6-dimethylphenol, or 2,2'-methylene-bis- (6-t-butyl-methylphenol), 4,4'-oxydiphenyl, 3,4 -Methylenedioxydiphenol (sesame oil), 3,4-dimethylphenol, benzcatechin (1,2-dihydroxybenzol), 2- 1'-methylcyclohexyl-1'-yl) -4,6-dimethylphenol, 2- or 4- (1'-phenyleth-1'-yl) phenol, 2-t-butyl-6-methylphenol, 2 , 4,6-Tris-t-butylphenol, 2,6-di-t-butylphenol, nonylphenol [CAS-Nr. 11066-49-2], octylphenol [CAS-Nr. 140-66-9], 2,6-dimethylphenol, bisphenol A, bisphenol B, bisphenol C, bisphenol F, bisphenol S, 3,3 ', 5,5'-tetrabromobisphenol A, 2,6-di- t-butyl-p-cresol, BASF Aktiengesellschaft, Koresin, 3,5-di-t-butyl-4-hydroxybenzoic acid methyl ester, 4-t-butylbenzcatechin, 2-hydroxybenzyl alcohol, 2- Methoxy-4-methylphenol, 2,3,6-trimethylphenol, 2,4,5-trimethylphenol, 2,4,6-trimethylphenol, 2-isopropylphenol, 4-isopropylphenol, 6-isopropyl-m- Cresol, n-oct Tadecyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1, 3,5-trimethyl-2,4,6-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzol, 1,3,5-tris- (3,5-di-tert-butyl -4-hydroxybenzyl) isocyanurate, 1,3,5-tris- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl-isocyanurate, 1,3,5-tris- (2 , 6-Dimethyl-3-hydroxy-4-t-butylbenzyl) isocyanurate or pentaerythrit-tetrakis- [β- (3,5-di-t-butyl-4-hydroxyphenyl) propione 2,6-di-t-butyl-4-dimethylaminomethylphenol, 6-s-butyl-2,4-dinitrophenol, Irganox 565, 1010, 1076, 1141 from Firma Ciba Specialiaetenchemie 1192, 1222 and 1425, 3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionic acid octadecyl ester. 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid hexadecyl ester, 3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid Octyl ester, 3-thia-1,5-pentanediol-bis- [3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate], 4,8-dioxa-1,11-undecanediol -Bis- [3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate], 4,8-dioxa-1,11-undecandiol-bis-[(3'-t-butyl-4 '-Hydroxy-5'-methylphenyl) propionate], 1,9-nonanediol-bis-[(3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] 1,7-heptanediamine-bis [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionic acid amide], 1,1-methanediamine-bis [3- (3 ′, 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid amide], 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid hydrazide, 3- (3' , 5'-dimethyl-4'-hydroxyphenyl) propionic hydrazide, bis- (3-tert-butyl-5-ethyl-2-hydroxyphen-1-yl) methane, bis- (3,5-di-t -Butyl-4-hydroxyphen-1-yl) methane, bis- [3- (1'-methylcyclohex-1'-yl) -5-methyl-2-hydroxyphen-1-yl] methane, bis- ( 3-t-butyl- -Hydroxy-5-methylphen-1-yl) methane, 1,1-bis- (5-tert-butyl-4-hydroxy-2-methylphen-1-yl) ethane, bis- (5-tert-butyl-4-) Hydroxy-2-methylphen-1-yl) sulfide, bis- (3-tert-butyl-2-hydroxy-5-methylphen-1-yl) sulfide, 1,1-bis- (3,4-dimethyl-2- Hydroxyphen-1-yl) -2-methylpropane, 1,1-bis- (5-tert-butyl-3-methyl-2-hydroxyphen-1-yl) butane, 1,3,5-tris- [ 1 '-(3 ", 5" -di-t-butyl-4 "-hydroxyphen-1" -yl) methy-1'-yl] -2,4,6-trimethylbenzol, 1,1,4- Tris- (5'-t-butyl-4'-hydroxy Cis-2'-methylphen-1'-yl) butane and t-butylcatechol, and aminophenols such as p-aminophenol, nitrosophenols such as p-nitrosophenol, p-nitroso-o-cresol, alkoxyphenols For example, 2-methoxyphenol (guaiacol, benzcatechin monomethyl ether), 2-ethoxyphenol, 2-isopropoxyphenol, 4-methoxyphenol (hydroquinone monomethyl ether), mono- or di-t-butyl-4-methoxyphenol 3,5-di-t-butyl-4-hydroxyanisole, 3-hydroxy-4-methoxybenzyl alcohol, 2,5-dimethoxy-4-hydroxybenzyl alcohol (syringa alcohol), 4-hydroxy-3-meth Sibenzaldehyde (vanillin), 4-hydroxy-3-ethoxybenzaldehyde (ethylvanillin), 3-hydroxy-4-methoxybenzaldehyde (isovanillin), 1-((4-hydroxy-3-methoxyphenyl) ethanone (acetovanillin), Eugenol, dihydroeugenol, isoeugenol, tocopherol, for example α-, β-, γ-, δ- and ε-tocopherol, tocol, α-tocopherol hydroquinone, and 2,3-dihydro-2,2-dimethyl-7- Hydroxybenzofuran (2,2-dimethyl-7-hydroxycoumaran).

  Examples of quinone and hydroquinone include hydroquinone or hydroquinone monomethyl ether (4-methoxyphenol), methylhydroquinone, 2,5-di-t-butylhydroquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, Trimethylhydroquinone 4-methylbenzcatechin, t-butylhydroquinone, 3-methylbenzcatechin, benzoquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, t-butylhydroquinone, 4-ethoxyphenol, 4 -Butoxyphenol, hydroquinone monobenzyl ether, p-phenoxyphenol, 2-methylhydroquinone, tetramethyl-p-benzoquinone, diethyl-1,4-cyclohexanedione-2,5- Carboxylate, phenyl-p-benzoquinone, 2,5-dimethyl-3-benzyl-p-benzoquinone, 2-isopropyl-5-methyl-p-benzoquinone (thymoquinone), 2,6-diisopropyl-p-benzoquinone, 2, 5-dimethyl-3-hydroxy-p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, envelopen, tetrahydroxy-p-benzoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2-amino-5-methyl -P-benzoquinone, 2,5-bisphenylamino-1,4-benzoquinone, 5,8-dihydroxy-1,4-naphthoquinone, 2-anilino-1,4-naphthoquinone, anthraquinone, N, N-dimethylindoaniline N, N-diphenyl-p-benzoquinone diimine, 1,4-benzox Dioxime, cerlignon, 3,3'-di-t-butyl-5,5'-dimethyldiphenoquinone, p-rosoleic acid (orine), 2,6-di-t-butyl-4-benzylidene-benzoquinone, 2 , 5-di-tert-butyl-amylhydroquinone is preferred.

  Moreover, as N-oxyl (a nitroxyl- or N-oxyl-group, a compound having at least one> NO— group), for example, 4-hydroxy-2,2,6,6-tetramethyl- Piperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-methoxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4- Acetoxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 2,2,6,6-tetramethyl-piperidine-N-oxyl, BASF Aktiengesellschaft, Uvinul 4040P, 4,4 ′, 4 "-Tris- (2,2,6,6-tetramethyl-piperidine-N-oxyl) phosphite, 3-oxo-2,2,5,5- Tetramethyl-pyrrolidine-N-oxyl, 1-oxyl-2,2,6,6-tetramethyl-4-methoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-trimethylsilyloxypiperidine, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-sebacate, 1 -Oxyl-2,2,6,6-tetramethylpiperidin-4-yl-stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-benzoate, 1-oxyl-2, 2,6,6-tetramethylpiperidin-4-yl- (4-t-butyl) benzoate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidi -4-yl) succinate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate, 1,10-decanedioic acid-bis- (1-oxyl-2,2, 6,6-tetramethylpiperidin-4-yl) ester, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) n-butylmalonate, bis- (1-oxyl- 2,2,6,6-tetramethylpiperidin-4-yl) phthalate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate, bis- (1-oxyl) -2,2,6,6-tetramethylpiperidin-4-yl) terephthalate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) hexahydroterephthalate N, N'-bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipinamide, N- (1-oxyl-2,2,6,6-tetramethylpiperidine -4-yl) caprolactam, N- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) dodecylsuccinimide, 2,4,6-tris- [N-butyl-N- (1 -Oxyl-2,2,6,6-tetramethylpiperidin-4-yl] triazine, N, N'-bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)- N, N'-bis-formyl-1,6-diaminohexane, 4,4'-ethylene-bis- (1-oxyl-2,2,6,6-tetramethylpiperazin-3-one) are preferred. .

  As aromatic amine or phenylenediamine, for example, N, N-diphenylamine, N-nitroso-diphenylamine, nitrosodiethylaniline, p-phenylenediamine, N, N'-dialkyl-p-phenylenediamine (in this case, the alkyl groups are the same) Or may be different, each independent of one another, containing 1 to 4 carbon atoms and may be linear or molecular)), for example, N, N′-di-iso-butyl-p-phenylenediamine N, N'-di-iso-propyl-p-phenylenediamine, Irumax 5057 from Firma Ciba Specialiaetenchie, N-phenyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N-isopropyl- N-phenyl-p-phenylenediamine N, N'-di-s-butyl-p-phenylenediamine (Kerobit BPD from BASF Aktiengesellschaft), N-phenyl-N'-isopropyl-p-phenylenediamine (Vulkanox 4010 from Bayer AG) N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N-phenyl-2-naphthylamine, iminodibenzyl, N, N′-diphenylbenzidine, N-phenyltetraaniline, acridone, 3-hydroxydiphenylamine and 4-hydroxydiphenylamine are preferred.

  Examples of imines include methylethylimine, (2-hydroxyphenyl) benzoquinoneimine, (2-hydroxyphenyl) benzophenoneimine, N, N-dimethylindoaniline, and thionine (7-amino-3-imino-3H-phenothiazine). , Methylene violet (7-dimethylamino-3-phenothiazinone).

  Examples of sulfonamides that are effective as radical polymerization inhibitors include N-methyl-4-toluolsulfonamide, Nt-butyl-4-toluolsulfonamide, Nt-butyl-N-oxyl-4-toluene. Allsulfonamide, N, N′-bis (4-sulfanilamide) piperidine, 3-{[5- (4-aminobenzoyl) -2,4-dimethylbenzoylsulfonyl] ethylamino} -4-methylbenzolsulfonic acid is there.

  Examples of oximes effective as radical polymerization inhibitors include aldoxime, ketoxime or amidoxime, preferably diethyl ketoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime, benzaldehyde oxime, benzyldioxime, dimethylglyoxime, 2-pyridine aldoxime, Salicylaldoxime, phenyl-2-pyridylketoxime, 1,4-benzoquinone dioxime, 2,3-butanedione dioxime, 2,3-butanedione monooxime, 9-fluorenone oxime, 4-t-butyl-cyclohexanone Oxime, N-ethoxy-acetimidic acid ethyl ester, 2,4-dimethyl-3-pentanone oxime, cyclododecanone oxime, 4-heptanone oxime and di-2-furanylethanedione It may be an oxime or other aliphatic or aromatic oxime or alkyl transfer agent such as its reaction product with an alkyl halide, -triflate, -sulfonate, -tosylate, -carbonate, -sulfate, -phosphate, etc. .

  Examples of the hydroxylamine include N, N-diethylhydroxylamine and compounds described in PCT / EP / 03/03139 international patent application.

  As the urea derivative, for example, urea or thiourea is suitable.

  The phosphorus-containing compound is, for example, triphenylphosphine, triphenylphosphite, hypophosphorous acid, trinonylphosphite, triethylphosphite or diphenylisopropylphosphine.

  Suitable sulfur-containing compounds are, for example, diphenyl sulfide, phenothiazine and sulfur-containing natural substances such as cysteine.

  Complexing agents based on tetraazaannulene (TAA) are described, for example, in Chem. Soc. Rev. 1998, 27, 105-115, for example, dibenzotetraaza [14] ring and porphyrin.

  In addition, each metal salt (copper, manganese, cerium, nickel, chromium, etc.) such as carbonic acid, chloride, dithiocarbamic acid, sulfuric acid, salicylic acid, acetic acid, stearic acid, and ethylhexanoic acid can be exemplified.

  Macromol. Rapid Commun. , 28, 1929 (2007), the N-oxyl free radical compound having a vinyl ether functional group has a structure having both a cationic polymerizable function and a radical scavenging function in the same molecule, from the viewpoint of curability and ink storage stability. It is preferable to add to the ink of the present invention. The polymer obtained by cationic polymerization of this N-oxyl free radical compound having a vinyl ether functional group is a polymer having a structure having a free radical in the side chain, such as solvent resistance, scratch resistance, and weather resistance. From the viewpoint of cured film properties and ink storage stability, it is preferably added to the ink of the present invention.

  The addition amount of the radical polymerization inhibitor is preferably 1.0 to 5000 μg / g ink, and more preferably 10 to 2000 μg / g ink. If it is 1.0 μg / g or more, desired storage stability can be obtained, ink thickening and liquid repellency with respect to the ink jet nozzle can be obtained, and this is preferable from the viewpoint of ejection stability. Moreover, if it is 5000 microgram / g ink or less, the high generation sensitivity can be maintained, without impairing the acid generation efficiency of a polymerization initiator.

(Cation polymerization inhibitor)
In the active energy ray-curable inkjet ink composition or inkjet ink of the present invention, a cationic polymerization inhibitor can also be added. Examples of the cationic polymerization inhibitor include alkali metal compounds, alkaline earth metal compounds, and amines.

  Preferred amines are alkanolamines, N, N-dimethylalkylamines, N, N-dimethylalkenylamines, N, N-dimethylalkynylamines and the like. Isopropanolamine, tributanolamine, N-ethyldiethanolamine, propanolamine, n-butylamine, sec-butylamine, 2-aminoethanol, 2-methylaminoethanol, 3-methylamino-1-propanol, 3-methylamino-1, 2-propanediol, 2-ethylaminoethanol, 4-ethylamino-1-butanol, 4- (n-butylamino) -1-butanol, 2- (t-butylamino) ethanol, N, N-dimethylundeca Nord, N, N-dimethyldodecanol N, N-dimethyltridecanolamine, N, N-dimethyltetradecanolamine, N, N-dimethylpentadecanolamine, N, N-dimethylnonadecylamine, N, N-dimethylicosylamine, N, N-dimethyleicosylamine, N, N-dimethylhenecosylamine, N, N-dimethyldocosylamine, N, N-dimethyltricosylamine, N, N-dimethyltetracosylamine, N, N-dimethyl Pentacosylamine, N, N-dimethylpentanolamine, N, N-dimethylhexanolamine, N, N-dimethylheptanolamine, N, N-dimethyloctanolamine, N, N-dimethylnonanolamine, N, N -Dimethyldecanolamine, N, N-dimethylnonylamine, N, N-dimethyldecylami N, N-dimethylundecylamine, N, N-dimethyldodecylamine, N, N-dimethyltridecylamine, N, N-dimethyltetradecylamine, N, N-dimethylpentadecylamine, N, N-dimethyl Examples include hexadecylamine, N, N-dimethylheptadecylamine, and N, N-dimethyloctadecylamine. In addition to these, quaternary ammonium salts and the like can also be used.

  The addition amount of the cationic polymerization inhibitor is preferably 50 to 5000 μg / g ink. If it is 50 μg / g or more, desired storage stability can be obtained, ink thickening and liquid repellency to the ink jet nozzle can be obtained, and this is preferable from the viewpoint of ejection stability. Moreover, if it is 5000 microgram / g ink or less, the high generation sensitivity can be maintained, without impairing the acid generation efficiency of a polymerization initiator.

《Other additives》
In the active energy ray-curable ink-jet ink composition or ink-jet ink of the present invention, in addition to the above description, emission stability, print head and ink packaging container compatibility, storage stability, image storage stability, etc. Various known additives such as surfactants, lubricants, fillers, antifoaming agents, gelling agents, thickeners, specific resistance adjusting agents, film forming agents, ultraviolet absorbers depending on the purpose of improving the performance of An agent, an antioxidant, a discoloration inhibitor, an antibacterial agent, a rust inhibitor and the like can be appropriately selected and used.

  Further, if necessary, a small amount of solvent such as ester solvent, ether solvent, ether ester solvent, ketone solvent, aromatic hydrocarbon solvent, nitrogen-containing organic solvent may be added.

  Specific examples include dimethyl sulfoxide, diethyl sulfoxide, methyl ethyl sulfoxide, diphenyl sulfoxide, tetraethylene sulfoxide, dimethyl sulfone, methyl ethyl sulfone, methyl-isopropyl sulfone, methyl-hydroxyethyl sulfone, sulfolane, or N-methyl-2- Pyrrolidone, 2-pyrrolidone, β-lactam, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone , Γ-butyrolactone, γ-valerolactone, isophorone, cyclohexanone, propylene carbonate, anisole, methyl ethyl ketone, acetone, ethyl lactate, butyl lactate, dioxane, ethyl acetate, butyrate , Diethylene glycol dimethyl ether, dibasic ester, methoxybutyl acetate, etc., can be mentioned. When these are added to the ink in an amount of 1.5 to 30%, preferably 1.5 to 15%, adhesion to a resin recording medium such as polyvinyl chloride is improved.

  Other specific examples include alkylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and alkylenes such as ethylene glycol dibutyl ether and tetraethylene glycol dimethyl ether. Examples include glycol dialkyl ethers, alkylene glycol monoalkyl ether acetates such as ethylene glycol monobutyl ether acetate, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate, and propylene glycol diacetate.

  Examples of the surfactant that can be used in the active energy ray-curable inkjet ink composition or inkjet ink of the present invention include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic such as alkylamine salts and quaternary ammonium salts Surfactants, silicone-based and fluorine-based surfactants are exemplified, and silicone-based or fluorine-based surfactants are particularly preferable.

  By adding a silicone-based or fluorine-based surfactant, it is possible to further suppress ink mixing on recording media made of various hydrophobic resins such as vinyl chloride sheets and recording media that absorb slowly such as printing paper. And high-quality printed images can be obtained. The surfactant is particularly preferably used in combination with the low surface tension water-soluble organic solvent.

  The silicone-based surfactant is preferably a polyether-modified polysiloxane compound. For example, KF-351A, KF-642, X-22-4272 manufactured by Shin-Etsu Chemical, BYK345, BYK347, BYK348 manufactured by Big Chemie, etc. Is mentioned.

  The fluorine-based surfactant means a compound in which a part or all of the surfactant is substituted with fluorine in place of hydrogen bonded to carbon of the hydrophobic group of a normal surfactant. Of these, those having a perfluoroalkyl group in the molecule are preferred.

  Among the fluorosurfactants, some are from DIC under the trade name Megafac F and from Asahi Glass under the trade name Surflon, Minnesota Mining and Manufacturing Company Under the trade name of Fluorad FC from the company, under the trade name of Monflor from Imperial Chemical Industry, and under the trade name of Zonyls from EI DuPont Nemeras & Company, Also, the product name of Licobet VPF is available from Farbeberke-Hoechst and the name of footage is available from Neos.

  The addition amount of the surfactant is preferably 0.1% by mass or more and less than 2.0% by mass with respect to the total mass of the ink.

  If the surface tension of the ink is 15 mN / m or more, the area around the nozzles of the inkjet head does not get wet and the discharge capacity does not decrease. If the surface tension is less than 35 mN / m, the surface energy is lower than that of normal paper. This is preferable because the recording medium made of paper or resin is well wetted and does not cause whitening.

<Ink physical properties>
The physical properties of the inkjet ink of the present invention preferably have the same physical properties as those of a normal active energy ray-curable inkjet ink. That is, the viscosity is 2 to 50 mPa · s at 25 ° C., the share rate dependency is as small as possible, the surface tension is in the range of 22 to 35 mN / m at 25 ° C., and when a pigment is used as the colorant, It is preferable that there is no gel-like substance having an average particle size exceeding 1.0 μm other than the particles, the conductivity is 10 μS / cm or less, and the ink is free from electrical corrosion inside the head. . 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 addition, as a physical property of the ink-jet ink of the present invention, a more preferable form is that the calorific value per unit mass is obtained when the DSC measurement of the ink is performed in the range of 25 ° C. to −25 ° C. at a rate of 5 ° C. per minute. The exothermic peak of 10 mJ / mg or more is not exhibited. By selecting a material according to the configuration of the present invention, it is possible to suppress heat generation of a certain amount or more in DSC measurement. By adopting such a configuration, even when the ink is stored at a low temperature, the generation of gel and the generation of precipitates can be suppressed.

<Method for preparing inkjet ink>
The ink-jet ink of the present invention comprises an active energy ray-curable compound, a polymerizable compound, a photopolymerization initiator, a pigment dispersant as a colorant, and a pigment as a colorant. It is manufactured by well dispersing using a disperser. It is preferable to prepare a concentrated solution having a high pigment concentration in advance and dilute with a polymerizable compound. Sufficient dispersion is possible even with dispersion by ordinary dispersers. Therefore, excessive dispersion energy is not applied and a large amount of dispersion time is not required, so it is difficult to cause deterioration during dispersion of ink components, and stability. Can be prepared. The prepared ink is preferably filtered through a filter having a pore diameter of 3 μm or less, and more preferably 1 μm or less.

"recoding media"
As a recording medium used in the inkjet recording method of the present invention, a wide range of conventional synthetic resins used in various applications are all targeted, and specifically, for example, polyester, polyvinyl chloride, polyethylene, polyurethane, polypropylene , Acrylic resin, polycarbonate, polystyrene, acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polybutadiene terephthalate and the like, and the thickness and shape of these synthetic resin substrates are not limited at all. In addition, metals, glass, printing paper, etc. can be used.

  Specific examples of polyvinyl chloride, which is one of the recording media used in the ink jet recording method of the present invention, include SOL-371G, SOL-373M, SOL-4701 (manufactured by Big Technos Co., Ltd.), glossy PVC (Co., Ltd.). Systemgraph Co., Ltd.), KSM-VS, KSM-VST, KSM-VT (above, manufactured by Kimoto Co., Ltd.), J-CAL-HGX, J-CAL-YHG, J-CAL-WWWG (above, Showa Co., Ltd.) (Made in Osaka), BUS MARK V400 F vinyl, litecal V-600F vinyl (above, made by Flexcon), FR2 (made by Hanwha) LLBAU13713 (above, made by Sakurai Co., Ltd.), P-370B, P-400M (above , Manufactured by Kambo Plus Co., Ltd.), S02P, S12P S13P, S14P, S22P, S24P, S34P, S27P (above, manufactured by Grafityp), P-223RW, P-224RW, P-249ZW, P-284ZC (above, manufactured by Lintec Corporation), LKG-19, LPA-70 , LPE-248, LPM-45, LTG-11, LTG-21 (above, manufactured by Shinsei Co., Ltd.), MPI 3023 (manufactured by Toyo Corporation), Napoleon Gloss gloss PVC (manufactured by Futaki Electronics Co., Ltd.), JV-610, Y-114 (above, manufactured by ICC Corporation), NIJ-CAPVC, NIJ-SPVCGT (above, manufactured by Nichie Corporation), 3101 / H12 / P4, 3104 / H12 / P4, 3104 / H12 / P4S 9800 / H12 / P4, 3100 / H12 / R2, 3 101 / H12 / R2, 3104 / H12 / R2, 1445 / H14 / P3, 1438 / One Way Vision (manufactured by Inetrcoat), JT5129PM, JT5728P, JT5822P, JT5829P, JT5829R, JT5829PM, JT5829PM, JM59t MPI1005, MPI1900, MPI2000, MPI2001, MPI2002, MPI3000, MPI3021, MPI3500, MPI3501 (above, manufactured by Avery), AM-101G, AM-501G (above, manufactured by Ginichi Co., Ltd.), FR2 (Hanfa Japan Co., Ltd.), AY-15P, AY-60P, AY-80P, DBSP137GGH, DBSP137GGL (above, Inc.) Insight Co., Ltd.), SJT-V200F, SJT-V400F-1 (above, manufactured by Hiraoka Orizome Co., Ltd.), SPS-98, SPSM-98, SPSH-98, SVGL-137, SVGS-137, MD3-200, MD3-301M, MD5-100, MD5-101M, MD5-105 (manufactured by Metamark), 640M, 641G, 641M, 3105M, 3105SG, 3162G, 3164G, 3164M, 3164XG, 3164XM, 3165G, 3165SG, 3165M, 3169M , 3451SG, 3551G, 3551M, 3631, 3641M, 3651G, 3651M, 3651SG, 3951G, 3641M (above, manufactured by Orafol), SVTL-HQ130 (manufactured by Lamy Corporation), SP 00 GWF, SPCLEARAD vinyl (above, manufactured by Catalina), RM-SJR (produced by Ryoyo Corporation), Hi Lucky, New Lucky PVC (above, made by LG), SIY-110, SIY-310, SIY-320 ( As described above, Sekisui Chemical Co., Ltd., PRINT MI Frontlit, PRINT XL Light weight banner (hereinafter, manufactured by Endutex), RIJET 100, RIJET 145, RIJET 165 (above, manufactured by Ritrama), NM-SG, NM-SM NEIEI KAKO Co., Ltd.), LTO3GS (Lukio Co., Ltd.), Easy Print 80, Performance Print 80 (above, Jetgraph Co., Ltd.), DSE 550, DSB 550, DSE 800 G, DSE 802/137, V250WG, V300WG, V350WG (above, manufactured by Hexis), Digital White 6005PE, 6010PE (above, made by Multifix), and the like.

  In addition, as a recording medium having a resin base material that does not contain a plasticizer or a non-absorbing inorganic base material as a constituent element, the following various base materials are used as constituent elements, and one kind of base material is used alone, or a plurality of kinds are used. These substrates can be used in combination. Examples of the resin base material containing no plasticizer used in the present invention include ABS resin, polycarbonate (PC) resin, polyacetal (POM) resin, polyamide (PA) resin, polyethylene terephthalate (PET) resin, and polyimide (PI). Examples thereof include a resin, an acrylic resin, a polyethylene (PE) resin, a polypropylene (PP) resin, and a hard polyvinyl chloride (PVC) resin that does not contain a plasticizer.

  These resins are characterized by not containing a plasticizer, but there are no particular restrictions on other properties such as thickness, shape, color, softening temperature, and hardness.

  The recording medium used in the present invention is preferably ABS resin, PET resin, PC resin, POM resin, PA resin, PI resin, hard PVC resin containing no plasticizer, acrylic resin, PE resin, or PP resin. More preferred are ABS resin, PET resin, PC resin, PA resin, hard PVC resin not containing plasticizer, and acrylic resin.

  Moreover, as a non-absorbing inorganic base material used for this invention, a metal plate, such as a glass plate, iron, and aluminum, a ceramic plate etc. are mentioned, for example. These inorganic substrates are characterized by not having an ink-absorbing layer on the surface. These non-absorbing inorganic base materials are not particularly limited with respect to other properties such as thickness, shape, color, softening temperature, and hardness.

  The inkjet ink of the present invention can exhibit the effects of the present invention particularly well in a recording medium having a surface energy of 25 mN / m or more and less than 50 mN / m. Examples of the surface energy of the recording medium include, for example, IJ180CV2 (manufactured by 3M, polyvinyl chloride, surface energy = 38.0 mN / m), MD5 (manufactured by Metamark, polyvinyl chloride, surface energy = 36.6 mN / m). ), ORAJET (manufactured by ORACAL, polyvinyl chloride, surface energy = 33.1 mN / m), OPAQUE MATT FILM (manufactured by Oce, polyethylene terephthalate, surface energy = 35.4 mN / m), Tokuhishi Art (Mitsubishi Paper) Manufactured, art paper, surface energy = 37.6 mN / m), HANITA (manufactured by Hanita Coating, polyethylene terephthalate, surface energy = 35.4 mN / m), Lumirror 38-T60 (manufactured by Toray Industries, untreated polyethylene terephthalate, surface Energy = 36.9m N / m), Sun Lloyd Uni G400 (manufactured by Sumitomo Bakelite Co., Ltd., polyvinyl chloride, surface energy = 34.5 mN / m), Sumipex 068 (manufactured by Sumitomo Chemical Co., Ltd., acrylic cast, surface energy = 39.5 mN / m), Sun Lloyd Pet Ace EPG400 (Sumitomo Bakelite, non-crystalline polyethylene terephthalate, surface energy = 35.7 mN / m), Lintec gloss (cast coated paper, surface energy 27 mN / m), Maru Adhesive White PET # 50 solvent strength Examples thereof include viscous PGS (polyethylene terephthalate, surface energy 50 mN / m).

  The surface energy of the recording medium according to the present invention can be calculated by measuring the contact angle using two or more kinds of liquids having known surface tensions.

<Inject recording method>
The ink-jet head used when forming an image by discharging the ink-jet ink of the present invention may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, thermal ink jet) Any ejection method such as a mold, a bubble jet (registered trademark) mold, or the like may be used.

  The ink jet recording method of the present invention is a recording method in which the active energy ray-curable ink jet ink of the present invention is ejected onto a recording medium from an ink jet nozzle and then irradiated with active energy rays such as ultraviolet rays to cure the ink. .

(Activation energy ray irradiation conditions after ink landing)
In the ink jet recording method of the present invention, the active energy ray is preferably irradiated for 0.001 second to 1.0 second after ink landing, more preferably 0.001 second. ~ 0.5 seconds.

  In order to form a high-definition image, it is preferable that the irradiation timing is as early as possible.

  The irradiation method of an active energy ray is not specifically limited, For example, it can carry out with the following method.

  A light source is provided on both sides of the head unit described in JP-A-60-132767, and the head and the light source are scanned by a shuttle method. Irradiation is performed after a certain period of time after ink landing, and is not accompanied by driving. A method of completing curing with another light source, a method using an optical fiber as described in US Pat. No. 6,145,979, or a collimated light source is applied to a mirror surface provided on the side of the head unit, and the recording unit is irradiated with ultraviolet rays. The method of doing can be mentioned.

  Any of these irradiation methods can be used in the inkjet recording method of the present invention.

  Also, the irradiation of active energy rays is divided into two stages. First, the active energy rays are irradiated by the above-described method within 0.001 to 2.0 seconds after ink landing, and after the completion of all printing, the active energy rays are further irradiated. The method of irradiating is also a preferred embodiment.

  By dividing the irradiation of the active energy ray into two stages, it is possible to further suppress the shrinkage of the recording material that occurs during ink curing.

(Total ink film thickness after ink landing)
In the ink jet recording method of the present invention, the total ink film thickness after ink has landed on the recording medium and cured by irradiation with active energy rays is 2 to 20 μm. It is preferable from the aspect of the texture change.

  Here, “total ink film thickness” means the maximum value of the film thickness of the ink drawn on the recording medium, and even for a single color, other two color layers (secondary colors), three color layers, Even when recording is performed using a four-color overlapping (white ink base) inkjet recording method, the meaning of the total ink film thickness is the same.

(Ink heating and ejection conditions)
In the inkjet recording method of the present invention, it is preferable from the viewpoint of ejection stability that the active energy ray-curable inkjet ink is heated and irradiated with the active energy ray.

  The temperature for heating is preferably 35 to 100 ° C., and more preferably in view of discharge stability and irradiation with active energy rays while being kept at 35 to 80 ° C.

  There is no particular limitation on the method of heating and keeping the ink-jet ink at a predetermined temperature.For example, an ink supply system such as an ink tank constituting a head carriage, a supply pipe, a front chamber ink tank immediately before the head, a pipe with a filter, There is a method in which a piezo head or the like is insulated and heated to a predetermined temperature by a panel heater, a ribbon heater, warm water or the like.

  The control range of the ink temperature is preferably set temperature ± 5 ° C., more preferably set temperature ± 2 ° C., and particularly preferably set temperature ± 1 ° C. from the viewpoint of ejection stability.

  The amount of liquid droplets ejected from each nozzle is preferably 2 to 20 pl from the viewpoint of recording speed and image quality.

  Next, an ink jet recording apparatus (hereinafter simply referred to as a recording apparatus) that can be used in the ink jet recording method of the present invention will be described.

  Hereinafter, the recording apparatus will be described with reference to the drawings as appropriate.

  FIG. 1 is a front view showing a configuration of a main part of the recording apparatus.

  The recording apparatus 1 includes a head carriage 2, a recording head 3, an irradiation unit 4, a platen unit 5, and the like.

  In the recording apparatus 1, the platen unit 5 is installed under the recording medium P.

  The platen unit 5 has a function of absorbing ultraviolet rays, and absorbs excess ultraviolet rays that have passed through the recording medium P.

  As a result, a high-definition image can be reproduced very stably.

  The recording medium P is guided by the guide member 6 and moves from the near side to the far side in FIG. 1 by the operation of the conveying means (not shown). A head scanning unit (not shown) scans the recording head 3 held by the head carriage 2 by reciprocating the head carriage 2 in the Y direction in FIG.

  The head carriage 2 is installed on the upper side of the recording medium P, and accommodates a plurality of recording heads 3 to be described later according to the number of colors used for image printing on the recording medium P, with the discharge ports arranged on the lower side.

  The head carriage 2 is installed with respect to the main body of the recording apparatus 1 in such a manner that it can reciprocate in the Y direction in FIG. 1, and reciprocates in the Y direction in FIG. 1 by driving the head scanning means.

  In FIG. 1, the head carriage 2 is white (W), yellow (Y), magenta (M), cyan (C), black (K), light yellow (Ly), light magenta (Lm), and light cyan (Lc). In the drawing, the recording head 3 for light black (Lk) and white (W) is drawn. However, in practice, the number of colors of the recording head 3 stored in the head carriage 2 is appropriately determined. Is.

  The recording head 3 is operated by a discharge means (not shown) provided with a plurality of active energy ray curable inkjet inks (for example, UV curable ink) supplied by an ink supply means (not shown). The ink is discharged from the discharge port toward the recording medium P.

  The recording head 3 is a certain area (landing possible area) in the recording medium P during the scanning in which the recording head 3 moves from one end of the recording medium P to the other end of the recording medium P in the Y direction in FIG. On the other hand, UV ink is ejected as ink droplets, and ink droplets are landed on the landable area.

  The above-described scanning is performed as many times as necessary, and the active energy ray-curable inkjet ink is ejected toward one landable area. Then, the recording medium P is appropriately moved from the front to the back in FIG. While performing scanning by the head scanning means, the recording head 3 discharges UV ink to the next landable area adjacent to the rearward direction in FIG.

  An assembly of active energy ray-curable inkjet ink droplets on the recording medium P by repeating the above operation and ejecting the recording head 3 or the active energy ray-curable inkjet ink in conjunction with the head scanning means and the conveying means. Is formed.

  The irradiation unit 4 includes, for example, an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength.

  Here, as the ultraviolet lamp, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (light emitting diode) and the like can be applied. A cathode tube, a hot cathode tube, a mercury lamp or black light is preferred.

  In particular, a low-pressure mercury lamp, a hot cathode tube, a cold cathode tube, and a germicidal lamp that emit ultraviolet light having a wavelength of 254 nm are preferable because they can prevent bleeding and control the dot diameter efficiently.

  By using black light as the radiation source of the irradiation means 4, the irradiation means 4 for curing the UV ink can be produced at low cost.

  The irradiating means 4 has substantially the same shape as the maximum one that can be set by the recording apparatus (UV inkjet printer) 1 among the landable areas in which the recording head 3 ejects UV ink by one scan driven by the head scanning means. , Having a shape larger than the landable area.

  The irradiation means 4 is fixed on both sides of the head carriage 2 so as to be substantially parallel to the recording medium P.

  As described above, as a means for adjusting the illuminance of the ink discharge portion, not only the entire recording head 3 is shielded, but in addition, the ink discharge of the recording head 3 is determined from the distance h1 between the irradiation means 4 and the recording medium P. It is effective to increase the distance h2 between the portion 31 and the recording medium P (h1 <h2) or to increase the distance d between the recording head 3 and the irradiation means 4 (d is increased).

  Further, it is more preferable that a bellows structure 7 is provided between the recording head 3 and the irradiation means 4.

  Here, the wavelength of the ultraviolet rays irradiated by the irradiation unit 4 can be changed as appropriate by exchanging the ultraviolet lamp or the filter provided in the irradiation unit 4.

  FIG. 2 is a top view illustrating another example of the configuration of the main part of the ink jet recording apparatus.

  The ink jet recording apparatus shown in FIG. 2 is called a line head system, and a plurality of ink jet recording heads 3 of each color are fixedly arranged on the head carriage 2 so as to cover the entire width of the recording medium P. ing.

  On the other hand, on the downstream side of the head carriage 2, that is, the rear portion of the head carriage 2 in the direction in which the recording medium P is conveyed, the entire width of the recording medium P is also covered so as to cover the entire ink printing surface. Arranged irradiation means 4 are provided.

  As the ultraviolet lamp used in the illuminating means 4, the same one as described in FIG. 1 can be used.

  In this line head system, the head carriage 2 and the irradiation means 4 are fixed, and only the recording medium P is conveyed, and ink ejection and curing are performed to form an image.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Preparation of pigment dispersion >>
(Preparation of pigment dispersion A)
61.0 parts of 2-phenoxyethyl acrylate as an organic solvent, 30.0 parts of Pigment Blue 15: 4 (Dainipei Seika Co., Ltd., Chromofine Blue 6332JC) as a pigment, Solspers 32000 (Japan) as a pigment dispersant In addition, 9.0 parts of Lubrizol Co., Ltd. was added and stirred with a high-speed mixer or the like until uniform, and the resulting mill base was dispersed for about 1 hour with a horizontal sand mill to prepare pigment dispersion A. .

(Preparation of pigment dispersion B)
28.0 parts of 2-phenoxyethyl acrylate as an organic solvent, 35.0 parts of Fanchon Fast Yellow Y-5688 (a nickel complex azo pigment manufactured by Bayer) as a pigment, and Solsperz 24000 (Nippon Lubrizol Corporation) as a pigment dispersant 7.0 parts of the company) was added and stirred with a high speed mixer or the like until uniform, and the resulting mill base was dispersed with a horizontal sand mill for about 1.5 hours to prepare Pigment Dispersion B.

(Preparation of pigment dispersion C)
64.0 parts of 2-phenoxyethyl acrylate as the organic solvent, 20.0 parts of Hostaperm Red E5B02 (Clariant quinacridone pigment) as the pigment, and Solsperz 24000 (Nippon Lubrizol Corporation) as the pigment dispersant. After adding 0 part and stirring with a high speed mixer or the like until uniform, the obtained mill base was dispersed with a horizontal sand mill for about 2 hours to prepare Pigment Dispersion C.

<Preparation of ink>
[Preparation of Ink 1: Present Invention]
The following additives were added to the pigment dispersion A to prepare ink 1 which is a radical polymerization type ink-jet ink.

Pigment Dispersion A 11.4 parts Radical polymerizable compound R1: 2-phenoxyethyl acrylate 35.0 parts Radical polymerizable compound R2: N-vinylcaprolactam 15.0 parts Radical polymerizable compound R3: Ethoxylated trimethylolpropane triacrylate
20.0 parts cationically polymerizable compound C1: Ebecryl 8402
(Bifunctional urethane oligomer manufactured by Daicel UCB) 5.5 parts Photoradical polymerization initiator: Irgacure 907
(Ciba Japan Co., Ltd., abbreviated as I907 in Table 1) 4.0 parts Photoradical polymerization initiator: Irgacure 819
(Abbreviation I819 in Table 1 manufactured by Ciba Japan Co., Ltd.) 4.0 parts Acrylic resin: BYK-361N (manufactured by BYK Chemie) 0.1 part Compound of general formula (1): Exemplified compound A-1
(3-methoxy-N, N-dimethylpropionamide) 5.0 parts [Preparation of inks 2 to 13]
In the preparation of ink 1, inks 2 to 10 (invention) and inks 11 to 13 (comparative example) were prepared in the same manner except that the types and addition amounts of the respective additives were changed as shown in Table 1. did.

  In addition, the detail of each additive described with the abbreviation in Table 1 is as follows.

<Polymerizable compound>
R1: 2-phenoxyethyl acrylate R2: N-vinylcaprolactam R3: ethoxylated trimethylolpropane triacrylate R4: isobornyl acrylate R5: tripropylene glycol triacrylate R6: propoxylated neopentyl glycol diacrylate C1: Ebecryl 8402 (Daicel UCB) Company bifunctional urethane oligomer)
<Photoradical polymerization initiator>
I819: Irgacure 819 (manufactured by Ciba Japan)
I907: Irgacure 907 (Ciba Japan)
<acrylic resin>
BYK: BYK-361N, manufactured by BYK Chemie <compound represented by general formula (1)>
A-1: 3-methoxy-N, N-dimethylpropionamide A-2: 3-n-butoxy-N, N-dimethylpropionamide A-3: 3-ethoxy-N, N-diethylpropionamide << Ink Evaluation
(Evaluation of line fault tolerance)
Using a piezo head 512LH (ink droplet amount: about 50 pl) manufactured by Konica Minolta IJ Co., Ltd., on a HANITA (manufactured by Hanita Coating, polyethylene terephthalate, surface energy = 35.4 mN / m) at a resolution of 360 × 360 dpi. Then, a solid image was printed by a single pass method, and a cured film was formed by irradiating light of 170 mJ / cm ² (as an integrated light amount of 365 nm) with a high-pressure mercury lamp. The time from printing to light irradiation was 100 milliseconds. In addition, dpi as used in the field of this invention represents the number of dots per 2.54 cm.

  The solid image formed was visually observed to confirm the occurrence of streaks, and the streak failure resistance was evaluated according to the following criteria.

○: No streaking is observed at all △: Slight streaking is confirmed, but at a level acceptable for practical use ×: Strong streaking is observed, and the quality is not practical (glossiness) Evaluation of)
The gloss state of the solid image formed by the evaluation of the streak failure resistance was visually observed, and the gloss feeling was evaluated according to the following criteria.

○: Excellent glossiness △: Slightly low glossiness is felt but practically acceptable quality ×: Image with poor glossiness and unacceptable quality Practical results Is shown in Table 1.

  As is clear from the results shown in Table 1, the radical polymerization type ink of the present invention containing the β-alkoxypropionamides represented by the general formula (1) is resistant to streak failure and gloss with respect to the comparative ink. An image excellent in feeling could be formed.

Example 2
<Preparation of ink set>
The inks prepared in Example 1 were combined as follows to obtain ink sets 1 to 3.

Ink set 1: Ink 7 + Ink 9 (present invention)
Ink set 2: Ink 8 + Ink 10 (present invention)
Ink set 3: ink 12 + ink 13 (comparative example)
<Evaluation of ink set>
Using the ink sets 1 to 3 prepared above, the mottling resistance was evaluated according to the following method.

(Evaluation of mottling resistance)
Each ink set is loaded into a piezo head 512MH (ink droplet amount: about 14 pl) manufactured by Konica Minolta IJ, and scanned eight times on a vinyl chloride sheet (IJ180CV2: manufactured by 3M) at a resolution of 720 × 720 dpi. Thus, a solid image of a secondary color was printed with two kinds of inks, and a cured film was formed by irradiating a light amount of 200 mJ / cm ² with an LED having a wavelength of 385 nm. Each time printing was performed in one scan, light irradiation was performed with a light amount of 20 mJ / cm ² per time, and the integrated light amount in eight scans was 160 mJ / cm ² .

  Observe the occurrence of mottling of the image formed by the above method according to the following criteria. Mottling resistance was evaluated.

○: No occurrence of mottling is observed at all △: Generation of extremely weak mottling is recognized, but at an acceptable level for practical use ×: Generation of strong mottling is observed, with an unacceptable quality for practical use Table 2 shows the results obtained.

  As is apparent from the results shown in Table 2, the ink set composed of the ink of the present invention containing the β-alkoxypropionamide represented by the general formula (1) is mottled compared to the comparative ink set. It can be seen that an image having excellent resistance is formed.

Example 3
<< Preparation of pigment dispersion >>
A pigment dispersion containing a pigment was prepared according to the following method.

(Pigment dispersion D)
The following two compounds were placed in a stainless beaker and dissolved by heating and stirring for 1 hour while heating on a 65 ° C. hot plate.

PB824 (manufactured by Ajinomoto Fine-Techno Co., Ltd., dispersant) 5.0 parts OXT-221 (manufactured by Toagosei Co., Ltd., oxetane compound) 80 parts After the above solution was cooled to room temperature, Pigment Blue 15: 4 (Daiichi Seisen as a pigment) Chemical Co., Ltd. (Chromofine Blue 6332JC) was added, and it was put in a glass bottle together with 200 g of zirconia beads having a diameter of 0.5 mm and sealed, and after 8 hours of dispersion with a paint shaker, the zirconia beads were removed. A pigment dispersion D was prepared.

(Preparation of pigment dispersion E)
The following two compounds were placed in a stainless beaker and dissolved by heating and stirring for 1 hour while heating on a 65 ° C. hot plate.

PB824 (manufactured by Ajinomoto Fine Techno Co., Ltd., dispersant) 5.0 parts OXT-221 (manufactured by Toagosei Co., Ltd., oxetane compound) 80 parts After cooling the above solution to room temperature, Pigment Yellow 150 (manufactured by LANXESS, 15 parts of LS Yellow G01) was added to 200 g of zirconia beads having a diameter of 0.5 mm and sealed in a glass bottle, and after 8 hours of dispersion treatment with a paint shaker, the zirconia beads were removed and pigment dispersion E Was prepared.

(Pigment dispersion F)
The following two compounds were placed in a stainless beaker and dissolved by heating and stirring for 1 hour while heating on a 65 ° C. hot plate.

PB824 (manufactured by Ajinomoto Fine Techno Co., Ltd., dispersant) 5.0 parts OXT-221 (manufactured by Toagosei Co., Ltd., oxetane compound) 80 parts After the above solution was cooled to room temperature, Pigment Red 122 (Daisen Seika Co., Ltd.) Add 15 parts of company chromofine red 6112JC), put it in a glass bottle together with 200g of zirconia beads with a diameter of 0.5mm, disperse with a paint shaker for 8 hours, remove the zirconia beads, and remove the pigment Dispersion F was prepared.

<Preparation of ink>
[Preparation of Ink 21]
The following additives were sequentially added and mixed, and then filtered through a Teflon (registered trademark) 3 μm membrane filter manufactured by ADVATEC to prepare ink 21 as a cationic polymerization type ink-jet ink.

Pigment dispersion D 10.0 parts OXT221: Oxetane compound, manufactured by Toagosei Co., Ltd. 47.68 parts OXT212: Oxetane compound, manufactured by Toagosei Co., Ltd. 10.0 parts Celoxide 2021P: Alicyclic epoxy compound, manufactured by Daicel Chemical Industries, Ltd. 20. 0 parts CPI-100P: Photoacid generator, manufactured by Sun Apro Co., Ltd. 5.0 parts DEA: 9,10-diethoxyanthracene, Kawasaki Chemical Industry Co., Ltd. 2.0 parts MAE: 2-methylaminoethanol 0.02 parts X-22: Silicone surfactant, X-22-4272, manufactured by Shin-Etsu Silicone
0.3 part A-1: General formula (1) Compound: exemplary compound A-1
(3-methoxy-N, N-dimethylpropionamide) 5.0 parts [Preparation of inks 22 to 33]
In the preparation of the ink 21, the inks 22 to 30 (present invention) and the inks 31 to 33 (comparative examples) were prepared in the same manner except that the types and addition amounts of the respective additives were changed as shown in Table 3. did.

  In addition, the detail of each additive described by the abbreviation in Table 3 is as follows.

OXT212: Oxetane compound, (3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, manufactured by Toagosei Co., Ltd.)
OXT221: Oxetane compound, (di [1-ethyl (3-oxetanyl)] methyl ether, manufactured by Toagosei Co., Ltd.)
2021P: Celoxide 2021P: (Daicel Chemical Industries, alicyclic epoxy compound)
CPI-100P: cationic polymerization initiator, 50% propylene carbonate triarylsulfonium salt solutions, Sun Apro Co., counter anions = PF ₆ ^- salt DEA: 9,10-diethoxy anthracene, Kawasaki Kasei Chemicals Ltd. MAE: 2-Methylaminoethanol X-22: Silicone-based surfactant, X-22-4272, manufactured by Shin-Etsu Silicone A-1: 3-methoxy-N, N-dimethylpropionamide A-2: 3-n-butoxy- N, N-dimethylpropionamide A-3: 3-ethoxy-N, N-diethylpropionamide << Evaluation of ink >>
The prepared cationic polymerization inks 21 to 33 were evaluated for streak failure resistance and glossiness in the same manner as described in Example 1, and the results obtained are shown in Table 3.

  As is apparent from the results shown in Table 3, the cationic polymerization type ink of the present invention containing the β-alkoxypropionamides represented by the general formula (1) is resistant to streak failure and gloss with respect to the comparative ink. An image excellent in feeling could be formed.

Example 4
<Preparation of ink set>
The inks prepared in Example 3 were combined as described below to form ink sets 4 to 6.

Ink set 4: ink 27 + ink 29 (present invention)
Ink set 5: ink 28 + ink 30 (present invention)
Ink set 6: ink 32 + ink 33 (comparative example)
<Evaluation of ink set>
Using the ink sets 4 to 6 prepared above, the mottling resistance was evaluated in the same manner as in the method described in Example 2, and the obtained results are shown in Table 4.

  As is apparent from the results shown in Table 4, the ink set constituted by the ink of the present invention containing the β-alkoxypropionamide represented by the general formula (1) was mottled relative to the comparative ink set. It can be seen that an image having excellent resistance is formed.

DESCRIPTION OF SYMBOLS 1 Recording device 2 Head carriage 3 Recording head 31 Ink ejection port 4 Irradiation means 5 Platen part 6 Guide member 7 Bellows structure 8 Irradiation light source P Recording medium

Claims (5)

An active energy ray-curable inkjet ink composition comprising a polymerizable compound, a photopolymerization initiator, and a β-alkoxypropionamide represented by the following general formula (1).

[Wherein R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, and R ₂ and R ₃ each represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. R ₂ and R ₃ may be the same or different. ]   2. The active energy ray-curable inkjet ink composition according to claim 1, comprising a radical polymerizable compound as the polymerizable compound and a photo radical polymerization initiator as the photo polymerization initiator.   2. The active energy ray-curable inkjet ink composition according to claim 1, wherein a cationic polymerizable compound is contained as the polymerizable compound, and a cationic photopolymerization initiator is contained as the photopolymerization initiator.   An inkjet ink comprising the active energy ray-curable inkjet ink composition according to any one of claims 1 to 3 and a colorant.   An ink jet recording method comprising: performing ink jet recording by discharging the ink jet ink onto a recording medium using the ink jet ink according to claim 4.

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