Inkjet ink, and production method of cured film

Abstract

To provide an active ray-curable inkjet ink including a polymerizable compound modified by amine, capable of forming a cured film having both high scratch resistance and high folding crack resistance.SOLUTION: An active ray-curable inkjet ink includes: a polymerizable compound (A) which is polymerized by irradiation of active rays; a photopolymerization initiator (B); and a gelatinizer (C). The polymerizable compound (A) includes an amine-modified polymerizable compound (A1), and the photopolymerization initiator (B) includes an ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing an ink-jet ink and a cured film. [Background technology]

[0002] There is known an actinic ray curable inkjet ink in which an ink is applied onto a substrate and then cured by irradiating with actinic rays such as ultraviolet rays or electron beams to form a cured film, etc. An actinic ray curable inkjet ink usually contains a polymerizable compound that polymerizes when irradiated with actinic rays, and a photopolymerization initiator for initiating polymerization of the polymerizable compound.

[0003] Patent Document 1 describes a photocurable inkjet ink that contains an amine-modified oligomer as a polymerizable compound. Patent Document 1 describes that by setting the amount of the amine-modified oligomer to 0.5 mass% or more in the inkjet ink and appropriately selecting the types and amounts of other polymerizable compounds and photopolymerization initiators, the surface curability of the ink is improved and a coating film (cured film) with excellent tackiness and abrasion resistance can be obtained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-007965 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, amine-modified polymerizable compounds such as amine-modified oligomers have the effect of enhancing the curability of inkjet inks. This is believed to be because amine-modified polymerizable compounds have both amino groups and polymerizable groups in the molecule, and therefore hydrogen abstraction by the amino groups and subsequent chain transfer reactions are likely to occur. Amine-modified polymerizable compounds are likely to have high reactivity due to the above-mentioned characteristics. As a result, amine-modified polymerizable compounds have high crosslink density and high hardness, and therefore tend to form cured films with high abrasion resistance.

[0006] On the other hand, as the hardness of the cured film increases, the flexibility decreases. Therefore, a cured film with high hardness is likely to crack when the substrate is folded (it is likely to have low resistance to folding cracks).

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an actinic ray-curable inkjet ink containing an amine-modified polymerizable compound, which is capable of forming a cured film having both high abrasion resistance and high resistance to fold cracking, and a method for producing a cured film using the inkjet ink. [Means for solving the problem]

[0008] One aspect of the present invention for solving the above problems relates to the following ink-jet inks [1] to [7]. [1] A composition comprising a polymerizable compound (A) that polymerizes when irradiated with actinic radiation, a photopolymerization initiator (B), and a gelling agent (C), the polymerizable compound (A) comprises an amine-modified polymerizable compound (A1); The photopolymerization initiator (B) contains ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide. Actinic radiation curing inkjet ink. [2] The content of the photopolymerization initiator (B) is 3% by mass or more and 10% by mass or less based on the total mass of the ink-jet ink. [1] An actinic ray-curable inkjet ink according to the above item. [1] The content of the amine-modified polymerizable compound (A1) is more than 0 mass % and 20 mass % or less based on the total mass of the inkjet ink. [1] or [2]. An actinic ray-curable inkjet ink. [4] The ratio (A1 / B) of the content of the amine-modified polymerizable compound (A1) to the content of the photopolymerization initiator (B) is greater than 0 and less than or equal to 8. The actinic ray-curable inkjet ink according to any one of [1] to [3]. [5] The ratio (A1 / B) of the content of the amine-modified polymerizable compound (A1) to the content of the photopolymerization initiator (B) is greater than 0 and less than or equal to 2. The actinic ray-curable inkjet ink according to any one of [1] to [4]. [6] The content of the gelling agent (C) is 0.5% by mass or more and 10% by mass or less based on the total mass of the ink-jet ink. The actinic ray-curable inkjet ink according to any one of [1] to [5]. [7] The photopolymerization initiator (B) includes bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide or diphenyl(2,4,6-trimethylbenzoyl)phenylphosphine oxide; The actinic ray-curable inkjet ink according to any one of [1] to [6].

[0009] Another aspect of the present invention for solving the above problems relates to a method for producing a cured film as described below in [8]. [8] A step of applying the inkjet ink according to any one of [1] to [7] to a substrate; irradiating the applied ink-jet ink with actinic radiation; The method for producing a cured film comprising the steps of: Effect of the Invention

[0010] The present invention provides an actinic ray-curable inkjet ink that contains an amine-modified polymerizable compound and is capable of forming a cured film having both high abrasion resistance and high resistance to fold cracking, and a method for producing a cured film using the inkjet ink. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 1. Inkjet ink One embodiment of the present invention relates to an actinic ray-curable inkjet ink (hereinafter, also simply referred to as "inkjet ink") that contains a polymerizable compound (A) that polymerizes when irradiated with actinic rays, a photopolymerization initiator (B), and a gelling agent (C).

[0012] Examples of active energy rays that can be used to cure the inkjet ink include electron beams, ultraviolet rays, α rays, γ rays, X-rays, etc. Of these, ultraviolet rays and electron beams are preferred, and ultraviolet rays are more preferred.

[0013] The components and physical properties that the ink-jet ink may contain will be described below.

[0014] 1-1.Ingredients 1-1-1. Polymerizable compound (A) The polymerizable compound (A) may be a radically polymerizable compound or a cationic polymerizable compound, of which the radically polymerizable compound is preferred.

[0015] The radically polymerizable compound is a polymerizable compound having an ethylenically unsaturated bond capable of radical polymerization in the molecule. Examples of the cationic polymerizable compound include an epoxy compound, a vinyl ether compound, and an oxetane compound.

[0016] The content of the polymerizable compound (A) can be from 1% by mass to 97% by mass, preferably from 30% by mass to 95% by mass, more preferably from 50% by mass to 90% by mass, and even more preferably from 70% by mass to 90% by mass, based on the total mass of the inkjet ink.

[0017] 1-1-1-1. Amine-modified polymerizable compound (A1) The polymerizable compound (A) includes an amine-modified polymerizable compound (A1). Examples of the amine-modified polymerizable compound (A1) include an amine-modified oligomer, a reactive amine coinitiator, a reactive amine synergist, an acrylate-modified amine synergist, an amine acrylate, and an amino acrylate. The amine-modified polymerizable compound (A1) is preferably an amine-modified oligomer. The amine-modified oligomer is a dimer or trimer or higher compound containing an amino group and a polymerizable group in the molecule. The amine-modified polymerizable compound may be an alkylene oxide-modified compound such as an ethylene oxide-modified or propion oxide-modified compound, or may be a compound that is not alkylene oxide-modified.

[0018] The molecular weight of the amine-modified polymerizable compound is not particularly limited, but is preferably 300 or more and 3,000 or less, and more preferably 400 or more and 2,000 or less.

[0019] The type of polymerizable group of the amine-modified polymerizable compound is not particularly limited, and may be a radically polymerizable functional group or a cationic polymerizable functional group, but from the viewpoint of increasing the curability by hydrogen abstraction of the amino group and obtaining a cured film with high scratch resistance, a radically polymerizable functional group is preferred. Examples of the radically polymerizable functional group include a vinyl group, an allyl group, a (meth)acryloyl group, a (meth)acrylamide group, a vinyl ether group, and an allyl ether group.

[0020] In this specification, "(meth)acrylic" means acrylic or methacrylic, "(meth)acrylate" means acrylate or methacrylate, "(meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylamide" means acrylamide or methacrylamide.

[0021] The number of polymerizable groups that the amine-modified polymerizable compound has in the molecule is not particularly limited, but from the viewpoint of increasing the hardness of the cured film and increasing the abrasion resistance, it is preferable that the number is 2 or more. The more the number of polymerizable groups, the higher the crosslinking density is, and the higher the abrasion resistance of the cured film is, or the less the unreacted polymerizable compound (A) is, and the more the peeling of the cured film at the cut surface is suppressed, or the migration or blooming of the unreacted polymerizable compound or the unreacted or reacted photopolymerization initiator from the cured film is suppressed. If the number of polymerizable groups is appropriately small, the decrease in the ejection property from the inkjet head due to the increase in the molecular weight of the amine-modified polymerizable compound can be suppressed.

[0022] The content of the amine-modified polymerizable compound (A1) is preferably more than 0% by mass and less than 20% by mass, more preferably 0.01% by mass or more and less than 8% by mass, and even more preferably 0.01% by mass or more and less than 2% by mass, based on the total mass of the inkjet ink. The higher the content of the amine-modified polymerizable compound (A1), the higher the scratch resistance of the cured film can be, the more the peeling of the cured film at the cut surface can be suppressed, and the more the migration or blooming of the unreacted polymerizable compound or the unreacted or reacted photopolymerization initiator from the cured film can be suppressed. The lower the content of the amine-modified polymerizable compound (A1), the less likely it is that fold cracks will occur. Furthermore, if the content of the amine-modified polymerizable compound (A1) is excessive, the reaction of other polymerizable compounds may be inhibited by the amine-modified polymerizable compound (A1); however, by setting the content of the amine-modified polymerizable compound (A1) within an appropriate range, it is possible to suppress the occurrence of fold cracks due to the loss of flexibility of the cured film caused by an increase in crosslinking points, and the migration and blooming of unreacted polymerizable compounds caused by the above-mentioned reaction inhibition.

[0023] 1-1-1-2. Other polymerizable compounds (A2) The polymerizable compound (A) may contain a polymerizable compound (A2) other than the amine-modified polymerizable compound (A1).

[0024] The other polymerizable compound (A2) may be either a radically polymerizable compound or a cationic polymerizable compound, but is preferably a radically polymerizable compound.

[0025] Examples of the radically polymerizable polymerizable compound (A2) include unsaturated carboxylic acids and their salts, unsaturated carboxylic acid ester compounds, unsaturated carboxylic acid urethane compounds, unsaturated carboxylic acid amide compounds and their anhydrides, acrylonitrile, styrene, unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes. Examples of unsaturated carboxylic acids include (meth)acrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid. Among these, unsaturated carboxylic acid esters such as (meth)acrylates are preferred, and (meth)acrylates are more preferred.

[0026] Examples of monofunctional (meth)acrylates include isoamyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, isomylstyryl (meth)acrylate, isostearyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, 2-ethylhexyl-diglycol (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-(meth)acryloyloxyethylhexahydrophthalic acid, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, o-phenylenediamine (meth)acrylate, methyl meth ... arylphenoxyethyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, ethoxylated phenoxy (meth)acrylate, alkoxylated phenol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-o-phenylphenolpropyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl-phthalate, and t-butylcyclohexyl (meth)acrylate.

[0027] Examples of polyfunctional (meth)acrylates include triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol diacrylate, dimethylol-tricyclodecane di(meth)acrylate, bisphenol A type di(meth)acrylate, and hydroxypivalin. Examples of the (meth)acrylates include difunctional (meth)acrylates such as acid neopentyl glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, and tripropylene glycol diacrylate, as well as trifunctional or higher (meth)acrylates such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin propoxy tri(meth)acrylate, and pentaerythritol ethoxy tetra(meth)acrylate.

[0028] Examples of the cationic polymerizable compound (A2) include epoxy compounds, vinyl ether compounds, and oxetane compounds.

[0029] Examples of the epoxy compounds include cycloaliphatic epoxy resins such as 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene monoepoxide, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate, 1-methyl-4-(2-methyloxiranyl)-7-oxabicyclo[4,1,0]heptane, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexanone-meta-dioxane and bis(2,3-epoxycyclopentyl)ether, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglyceride of glycerin, and the like. Examples of the epoxy compounds include aliphatic epoxy compounds including polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides (such as ethylene oxide and propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin, as well as di- or polyglycidyl ethers of bisphenol A or its alkylene oxide adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or its alkylene oxide adducts, and novolac-type epoxy resins.

[0030] Examples of the vinyl ether compound include monovinyl ether compounds including ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl ether-o-propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether, as well as di- or trivinyl ether compounds including ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, and trimethylolpropane trivinyl ether.

[0031] Examples of the oxetane compound include 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-hydroxymethyl-3-n-butyloxetane, 3-hydroxymethyl-3-phenyloxetane, 3-hydroxymethyl-3-benzyloxetane, 3-hydroxyethyl-3-methyloxetane, 3-hydroxyethyl-3-ethyloxetane, 3-hydroxyethyl-3-propyloxetane, 3-hydroxyethyl -3-phenyloxetane, 3-hydroxypropyl-3-methyloxetane, 3-hydroxypropyl-3-ethyloxetane, 3-hydroxypropyl-3-propyloxetane, 3-hydroxypropyl-3-phenyloxetane, 3-hydroxybutyl-3-methyloxetane, 1,4 bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane and di[1-ethyl(3-oxetanyl)]methyl ether.

[0032] 1-1-2. Photopolymerization initiator (B) The photopolymerization initiator (B) is a compound that initiates polymerization and crosslinking of the actinic ray-polymerizable compound by irradiation with light.

[0033] In this embodiment, the photopolymerization initiator (B) contains ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide (hereinafter, also simply referred to as "initiator (B1)"). Although the reason is unclear, the initiator (B1) has an appropriate curing speed, and therefore can suppress excessive polymerization of the polymerizable compound (A). Furthermore, in this embodiment, the movement of the polymerizable compound (A) is limited by the so-called house-of-cards structure formed by the gelling agent (C), and excessive chain transfer of the polymerizable compound (A) is further suppressed. It is believed that these actions increase the resistance to fold cracking of the cured film.

[0034] The content of the initiator (B1) is preferably from 0.5 to 10% by mass, more preferably from 1 to 8% by mass, even more preferably from 2 to 8% by mass, and even more preferably from 2 to 5% by mass, relative to the total mass of the inkjet ink.

[0035] The ratio (A1 / B1) of the content of the amine-modified polymerizable compound (A1) to the content of the photopolymerization initiator (B1) is preferably greater than 0 and less than 8, more preferably greater than 0 and less than 5, even more preferably greater than 0 and less than 2, even more preferably 0.05 to 1.5, and particularly preferably 0.1 to 1. The larger the ratio (A1 / B1), the more likely it is that the abrasion resistance of the cured film will be enhanced by the action of the amine-modified polymerizable compound (A1). In addition, the larger the ratio (A1 / B1), the more likely it is that the amount of unreacted polymerizable compound (A) can be reduced by chain transfer reaction, thereby suppressing peeling of the cured film on the cut surface. The smaller the ratio (A1 / B1), the more thoroughly the amine-modified polymerizable compound (A1) is reacted, thereby suppressing peeling, migration, and blooming of the cut surface caused by unreacted polymerizable compound (A), suppressing changes in gloss of the image caused thereby, and suppressing a decrease in fold crack resistance due to brittleness of the cured film caused by insufficient reaction, and a decrease in abrasion resistance due to insufficient curing at the surface of the cured film.

[0036] The photopolymerization initiator (B) may further contain bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide or diphenyl(2,4,6-trimethylbenzoyl)phenylphosphine oxide (hereinafter, these are also collectively referred to simply as "initiator (B2)"). When used in combination with the initiator (B1), these photopolymerization initiators efficiently polymerize the polymerizable compound (A), improve the surface curing properties of the cured film, and suppress peeling of the cured film on the cut surface.

[0037] The content of the initiator (B2) is preferably from 0 to 8% by mass, more preferably from 1 to 8% by mass, and even more preferably from 2 to 8% by mass, relative to the total mass of the inkjet ink.

[0038] The photopolymerization initiator (B) may contain a photopolymerization initiator (B3) other than the above-mentioned initiator (B1) or initiator (B2) (hereinafter, also simply referred to as "initiator (B3)").

[0039] The initiator (B3) may be an intramolecular bond cleavage type polymerization initiator, or an intramolecular hydrogen abstraction type polymerization initiator.

[0040] Examples of the intramolecular bond cleavage type radical polymerization initiator include acetophenone-based initiators such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-methylthiophenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, benzoin-based initiators such as benzoin, benzoin methyl ether, and benzoin isopropyl ether, benzyl, and methylphenyl glyoxyesters.

[0041] Examples of the intramolecular hydrogen abstraction type radical polymerization initiator include benzophenone-based initiators such as benzophenone, o-benzoylmethylbenzoate, 4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone-based initiators such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone; aminobenzophenone-based initiators such as Michler's ketone and 4,4'-diethylaminobenzophenone; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, and camphorquinone.

[0042] When the polymerizable compound (A) contains a cationic polymerizable compound, the initiator (B3) may contain a cationic polymerization initiator. Examples of cationic polymerization initiators include photoacid generators. Examples of photoacid generators include aromatic onium compounds including diazonium, ammonium, iodonium, sulfonium, and phosphonium, etc., such as B(C 6 F 5 ) 4 - , P.F. 6 - , AsF 6 - , SbF 6 - , C.F. 3 SO 3 - These include salts, sulfonates which generate sulfonic acids, halides which photogenerate hydrogen halides, and iron-allene complexes.

[0043] The content of the photopolymerization initiator (B) is preferably 1.5% by mass or more and 12% by mass or less, more preferably 3% by mass or more and 10% by mass or less, and even more preferably 5% by mass or more and 8% by mass or less, based on the total mass of the inkjet ink. The higher the content of the photopolymerization initiator (B), the higher the curability of the inkjet ink can be. If the content of the photopolymerization initiator (B) is appropriately low, migration or blooming of the unreacted or reacted photopolymerization initiator from the cured film can be suppressed.

[0044] The ratio (A1 / B) of the content of the amine-modified polymerizable compound (A1) to the content of the photopolymerization initiator (B) is preferably greater than 0 and less than 8, more preferably greater than 0 and less than 5, even more preferably greater than 0 and less than 2, even more preferably greater than 0.05 or more and less than 1.5, and particularly preferably greater than 0.1 or more and less than 1. The larger the ratio (A1 / B), the more likely it is that the abrasion resistance of the cured film will be enhanced by the action of the amine-modified polymerizable compound (A1). The larger the ratio (A1 / B), the more likely it is that the amount of unreacted polymerizable compound (A) will be reduced by a chain transfer reaction, thereby suppressing peeling of the cured film on the cut surface. The smaller the ratio (A1 / B), the more thoroughly the amine-modified polymerizable compound (A1) is reacted, thereby suppressing peeling, migration, and blooming of the cut surface caused by unreacted polymerizable compound (A), suppressing changes in gloss of the image caused thereby, and suppressing a decrease in fold crack resistance due to brittleness of the cured film caused by insufficient reaction, and a decrease in abrasion resistance due to insufficient curing at the surface of the cured film.

[0045] 1-1-3. Gelling agent (C) The gelling agent (C) is a compound that makes the inkjet ink gel at room temperature and makes the inkjet ink flowable when heated. The gelling agent (C) can quickly gel the inkjet ink applied to the substrate, thereby improving the pinning ability of the inkjet ink.

[0046] The gelling agent (C) is preferably a compound that dissolves in the actinic radiation polymerizable compound contained in the ink at a temperature higher than the gelling temperature of the ink-jet ink and crystallizes in the ink at a temperature equal to or lower than the gelling temperature of the ink. The "gelling temperature" refers to the temperature at which the ink undergoes a phase transition from sol to gel and the viscosity of the ink suddenly changes when the ink-jet ink that has been solated or liquefied by heating is cooled. Specifically, the temperature at which the viscosity of the ink suddenly increases when the ink that has been solated or liquefied is cooled while measuring the viscosity with a rheometer (e.g., MCR300 manufactured by Anton Paar) can be regarded as the gelling temperature of the ink.

[0047] The gelling agent (C) is preferably crystallized in the ink at a temperature below the gelling temperature of the inkjet ink, and forms a structure in which the polymerizable compound (A) is encapsulated in a three-dimensional space formed by the gelling agent (C) crystallized into a plate shape (such a structure is hereinafter referred to as a "house of cards structure"). When a house of cards structure is formed, the range in which the amine-modified polymerizable compound (A1) can move is also limited to the inside of the three-dimensional space. Therefore, the reaction between the amine-modified polymerizable compound (A1) encapsulated in one space and the amine-modified polymerizable compound (A1) encapsulated in another space is suppressed, and the chain transfer reaction by the amine-modified polymerizable compound (A1) also occurs only within a predetermined range. This is thought to suppress excessive crosslinking, so that the cured film does not cure excessively, and a cured film that is somewhat flexible and does not crack easily when bent is formed.

[0048] Examples of gelling agents (C) that tend to form a house-of-cards structure include aliphatic ketones, aliphatic esters, petroleum-based waxes, vegetable waxes, animal waxes, mineral waxes, hydrogenated castor oil, modified waxes, higher fatty acids, higher alcohols, hydroxystearic acid, fatty acid amides including N-substituted fatty acid amides and special fatty acid amides, higher amines, esters of sucrose fatty acids, synthetic waxes, dibenzylidene sorbitol, dimer acids and dimer diols.

[0049] Examples of aliphatic ketones include dilignoceryl ketone, dibehenyl ketone, distearyl ketone, dieicosyl ketone, dipalmityl ketone, dilauryl ketone, dimyristyl ketone, myristyl palmityl ketone, and palmityl stearyl ketone.

[0050] Examples of fatty esters include fatty acid esters of monoalcohols such as behenyl behenate, icosanoic acid ethyl ester, stearyl stearate, palmityl stearate, myristyl myristate, cetyl myristate, and oleyl palmitate; and fatty acid esters of polyhydric alcohols such as glycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, ethylene glycol fatty acid esters, and polyoxyethylene fatty acid esters.

[0051] Commercially available examples of the above aliphatic esters include the EMALEX series (manufactured by Nippon Emulsion Co., Ltd. ("EMALEX" is a registered trademark of the company)), the Rikemal series, and the Poem series (manufactured by Riken Vitamin Co., Ltd. ("Rikemal" and "Poem" are both registered trademarks of the company)).

[0052] Examples of higher fatty acids include behenic acid, arachidic acid, stearic acid, palmitic acid, myristic acid, lauric acid, oleic acid, and erucic acid.

[0053] Examples of higher alcohols include stearyl alcohol and behenyl alcohol.

[0054] Of these, from the viewpoint of more fully obtaining the effect of improving resistance to fold cracking due to the card house structure, the gelling agent (C) is preferably an aliphatic ketone, an aliphatic ester, a higher fatty acid, or a higher alcohol, and more preferably an aliphatic ketone represented by the following general formula (G1) or an aliphatic ester represented by the following general formula (G2). Only one type of gelling agent (C) may be contained, or two or more types may be contained in combination.

[0055] General formula (G1):R a -CO-R b General formula (G2):R c -COO-R d

[0056] R in general formula (G1) a and Rb each independently represents a linear hydrocarbon group having 12 to 26 carbon atoms, which may have a branched chain, and R in general formula (G2) c and R d each independently represents a linear hydrocarbon group having 12 to 26 carbon atoms, which may have a branched chain.

[0057] The gelling agent (C) shown in the general formula (G1) and (G2) is R a ~R d Since the number of carbon atoms is 12 or more, the crystallinity is high and a sufficiently large space is generated inside the house-of-cards structure, so that the effect of improving the resistance to fold cracking by including the polymerizable compound (A) is more sufficiently exhibited.

[0058] The gelling agent (C) represented by the general formulas (G1) and (G2) is R a ~R d Since the number of carbon atoms is 26 or less, the melting point is appropriately low and the solation temperature of the inkjet ink is not too high, so the heating temperature of the inkjet ink during ejection can be lowered.

[0059] Examples of aliphatic ketones represented by general formula (G1) include dilignoceryl ketone (carbon number: 23-24), dibehenyl ketone (carbon number: 21-22), distearyl ketone (carbon number: 17-18), dieicosyl ketone (carbon number: 19-20), dipalmityl ketone (carbon number: 15-16), dimyristyl ketone (carbon number: 13-14), dilauryl ketone (carbon number: 11-12), lauryl ketone (carbon number: 13-14), and glyceryl ketone (carbon number: 14-16). These include myristyl ketone (carbon number: 11-14), lauryl palmityl ketone (11-16), myristyl palmityl ketone (13-16), myristyl stearyl ketone (13-18), myristyl behenyl ketone (13-22), palmityl stearyl ketone (15-18), palmityl behenyl ketone (15-22) and stearyl behenyl ketone (17-22). The number of carbon atoms in the parentheses above indicates the number of carbon atoms in each of the two hydrocarbon groups separated by the carbonyl group.

[0060] Examples of commercially available products of the compound represented by general formula (G1) include 18-Pentatriacontanone and Hentriacontan-16-one (both manufactured by Alfa Aeser), and Kaowax T1 (manufactured by Kao Corporation).

[0061] Examples of the aliphatic ester represented by the general formula (G2) include behenyl behenate (carbon number: 21-22), icosanoic acid icosyl (carbon number: 19-20), stearyl stearate (carbon number: 17-18), palmityl stearate (carbon number: 17-16), lauryl stearate (carbon number: 17-12), cetyl palmitate (carbon number: 15-16), stearyl palmitate (carbon number: 15-18), myristyl Myristyl phosphate (carbon number: 13-14), cetyl myristate (carbon number: 13-16), octyldodecyl myristate (carbon number: 13-20), stearyl oleate (carbon number: 17-18), stearyl erucate (carbon number: 21-18), stearyl linoleate (carbon number: 17-18), behenyl oleate (carbon number: 18-22), and arachidyl linoleate (carbon number: 17-20). The number of carbons in the parentheses above indicates the number of carbons in each of the two hydrocarbon groups separated by the ester group.

[0062] Examples of commercially available aliphatic esters represented by general formula (G2) include Unistar M-2222SL, Sperm Acetate, Nissan Elector WEP-2 and Nissan Elector WEP-3 (all manufactured by NOF Corporation, "Unistar" and "Nissan Elector" are registered trademarks of the company), Exepar SS and Exepar MY-M (all manufactured by Kao Corporation, "Exepar" is a registered trademark of the company), EMALEX CC-18 and EMALEX CC-10 (manufactured by Nippon Emulsion Co., Ltd., "EMALEX" is a registered trademark of the company), and Amureps PC (manufactured by Kokyu Alcohol Kogyo Co., Ltd., "Amureps" is a registered trademark of the company). These commercially available products are often mixtures of two or more types, so they may be separated and purified as necessary before being added to the ink.

[0063] The content of the gelling agent (C) is preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 6% by mass or less, based on the total mass of the ink. The higher the content of the gelling agent (C), the more the density of the crosslinks formed by the amine-modified polymerizable compound (A1) can be suppressed, thereby increasing the fold crack resistance and abrasion resistance of the cured film, and the card house structure can contain the unreacted polymerizable compound (A) and photopolymerization initiator (B), etc., to suppress their blooming, thereby suppressing changes in the gloss of the image.

[0064] 1-1-4.Other ingredients The ink-jet ink may further contain colorants and other ingredients such as dispersants, surfactants, polymerization inhibitors, and humectants.

[0065] 1-1-4―1. Coloring agents The colorant may be a dye or a pigment, and is preferably a pigment from the viewpoint of forming a cured film having high weather resistance. The pigment may be selected from yellow pigments, red pigments, blue pigments, black pigments, and white pigments according to the color of the cured film to be formed and the image formed by assembling the cured films.

[0066] Examples of yellow pigments include Pigment Yellow (PY) 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193, and the like.

[0067] Examples of red pigments include Pigment Red (PR) 3, 5, 19, 22, 31, 38, 43, 48:1, 48:2, 48:3, 48:4, 48:5, 49:1, 53:1, 57:1, 57:2, 58:4, 63:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 104, 108, 112, 122, 123, 144, 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet (PV) 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange (PO) Includes 13, 16, 20, 36, etc.

[0068] Examples of blue pigments include Pigment Blue (PB) 1, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17:1, 22, 27, 28, 29, 36, 60, and the like.

[0069] Examples of green pigments include CI Pigment Green (hereinafter also simply referred to as "PG") 7, PG26, PG36, and PG50.

[0070] An example of a black pigment is CI Pigment Black (hereinafter, simply referred to as "PBk"). )7, PBk26, and PBk28.

[0071] Examples of the white pigment include inorganic pigments such as titanium oxide, zinc oxide, calcium carbonate, barium sulfate, and aluminum hydroxide. Among these, titanium oxide is preferred, and from the viewpoint of reducing the particle size of the white pigment, anatase-type titanium oxide is preferred, and from the viewpoint of improving the concealment of the image, rutile-type titanium oxide is preferred.

[0072] The content of the colorant is preferably from 0.1% to 10% by mass, and more preferably from 1% to 5% by mass, based on the total mass of the inkjet ink.

[0073] 1-1-4-2. Dispersants The dispersibility of the colorant, which is a pigment, may be improved by using a dispersant.

[0074] Examples of the dispersant include carboxylate esters having a hydroxy group, salts of long-chain polyaminoamides and high molecular weight acid esters, salts of high molecular weight polycarboxylic acids, salts of long-chain polyaminoamides and polar acid esters, high molecular weight unsaturated acid esters, polymer copolymers, modified polyurethanes, modified polyacrylates, polyether ester type anionic surfactants, naphthalenesulfonic acid formalin condensate salts, aromatic sulfonic acid formalin condensate salts, polyoxyethylene alkyl phosphate esters, polyoxyethylene nonylphenyl ether, and stearylamine acetate.

[0075] The content of the dispersant is preferably from 1% by mass to 50% by mass relative to the mass of the pigment.

[0076] 1-1-4-3.Surfactants Examples of surfactants include anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers; cationic surfactants such as alkylamine salts and quaternary ammonium salts; and silicone-based and fluorine-based surfactants.

[0077] The content of the surfactant can be, for example, 0.001% by mass or more and less than 1.0% by mass relative to the total mass of the ink-jet ink.

[0078] 1-1-4-4. Polymerization inhibitors Examples of the polymerization inhibitor include N-oxyl-based polymerization inhibitors, phenol-based polymerization inhibitors, quinone-based polymerization inhibitors, amine-based polymerization inhibitors, and copper dithiocarbamate-based polymerization inhibitors.

[0079] The content of the polymerization inhibitor is, for example, preferably from 0.01% by mass to 1% by mass, and more preferably from 0.05% by mass to 0.5% by mass, relative to the total mass of the ink-jet ink.

[0080] 1-2.Physical properties From the viewpoint of improving ejection properties from an inkjet head, the inkjet ink preferably has a viscosity at 80° C. of 3 mPa·s or more and 20 mPa·s or less, and more preferably 7 mPa·s or more and 9 mPa·s or less.

[0081] The inkjet ink preferably undergoes a sol-gel phase transition at a temperature of 40° C. or more and less than 100° C. The gelling temperature of the inkjet ink is preferably 40° C. or more and 70° C. or less. When the gelling temperature of the inkjet ink is 40° C. or more, the ink quickly gels after landing on a recording medium, resulting in higher pinning properties. When the gelling temperature of the ink is 70° C. or less, the ink is less likely to gel when ejected from an inkjet head, where the ink temperature is usually around 80° C., and therefore the ink can be ejected more stably.

[0082] The viscosity at 40°C, the viscosity at 80°C, and the gelling temperature of the inkjet ink can be determined by measuring the temperature change of the dynamic viscoelasticity of the ink using a rheometer (e.g., a stress-controlled rheometer, Physica MCR series, manufactured by Anton Paar). Specifically, the ink is heated to 100°C and cooled to 25°C under conditions of a shear rate of 11.7 (1 / s) and a temperature drop rate of 0.1°C / s, and a viscosity temperature change curve is obtained. The viscosities at 40°C and 80°C can be determined by reading the viscosities at 40°C and 80°C, respectively, on the viscosity temperature change curve. The gelling temperature can be determined as the temperature at which the viscosity becomes 200 mPa·s on the viscosity temperature change curve.

[0083] 1-3.Preparation method The inkjet ink can be prepared by mixing the above-mentioned components. At this time, it is preferable to mix the components while heating them in order to increase the solubility of each component.

[0084] Alternatively, a pigment dispersion containing the pigment and the dispersant may be prepared in advance, and the remaining components may be added and mixed therein. In this case, the pigment may be dispersed using, for example, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, or a paint shaker.

[0085] 2. Manufacturing method of the cured film The above-mentioned ink-jet ink can be used for forming a cured film on the surface or inside of the substrate by ejecting it from an ink-jet head and applying it to the surface of a substrate, and then curing it by irradiation with actinic rays.

[0086] The ejection method from the inkjet head may be either an on-demand method or a continuous method. The on-demand inkjet head may be any of electro-mechanical conversion methods such as single cavity type, double cavity type, bender type, piston type, shear mode type, and shared wall type, and electro-thermal conversion methods such as thermal inkjet type and bubble jet type ("Bubble Jet" is a registered trademark of Canon Inc.).

[0087] The type of substrate is not particularly limited. In addition to ordinary uncoated paper and coated paper, synthetic paper Yupo ("Yupo" is a registered trademark of Yupo Corporation), various plastics used in soft packaging, and their films can be used. Examples of various plastic films include polypropylene (PP) film, polyethylene terephthalate (PET) film, biaxially oriented polystyrene (OPS) film, biaxially oriented polypropylene (OPP) film, biaxially oriented nylon (ONy) film, polyvinyl chloride (PVC) film, polyethylene (PE) film, triacetyl cellulose (TAC) film, etc. Examples of other plastics include polycarbonate, (meth)acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS), polyacetal, polyvinyl alcohol (PVA9), rubbers, etc.

[0088] The inkjet ink discharged from the inkjet head may be applied directly to the substrate, or the inkjet ink may be applied to an intermediate transfer body and then transferred from the intermediate transfer body to be applied to the substrate.

[0089] Thereafter, the applied ink-jet ink is irradiated with actinic radiation to cure the ink-jet ink.

[0090] Examples of actinic rays include electron beams, ultraviolet rays, α rays, γ rays, and X-rays. Of these, ultraviolet rays and electron beams are preferred, and ultraviolet rays are more preferred. The ultraviolet rays are preferably light having a peak wavelength of 360 nm or more and 410 nm or less. The ultraviolet rays are preferably irradiated from a laser light-emitting diode (LED) light source. Since LEDs emit less radiant heat, they are less likely to dissolve the inkjet ink when irradiated with actinic rays, and are less likely to cause uneven gloss due to the dissolution of the ink.

[0091] When ultraviolet light is used as the actinic ray, the light quantity per irradiation is 500 mJ / cm 2 More than 4000mJ / cm 2 It is preferable that:

[0092] 3.Cured film By the above-mentioned method, a cured film can be formed on the surface of a substrate. The cured film can be used as a resin film having an image or various patterns. EXAMPLES

[0093] The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to the contents of the examples.

[0094] 1. Inkjet Ink Preparation (Preparation of Black Pigment Dispersion) 9 parts by mass of a pigment dispersant (Ajinomoto Fine-Techno Co., Ltd., Ajisper PB824), 70 parts by mass of a polymerizable compound (A2) (tripropylene glycol diacrylate), and 0.02 parts by mass of a polymerization inhibitor (Ciba Japan Co., Ltd., Irgastab UV10) were placed in a stainless steel beaker and heated and stirred for 1 hour while heating on a hot plate at 65 ° C. The above mixture was cooled to room temperature, and then 21 parts by mass of CI Pigment Black 7 (Mitsubishi Chemical Co., Ltd.) (pigment) was added to it. The mixture was placed in a glass bottle together with 200 g of zirconia beads with a diameter of 0.5 mm, sealed, and dispersed for 8 hours with a paint shaker. The zirconia beads were then removed to obtain a pigment dispersion.

[0095] Using the pigment dispersion liquid prepared above and the following materials, actinic ray curable inkjet inks 1 to 19 were prepared.

[0096] (Amine-modified polymerizable compound (A1)) A1-1: EBECRYL80 (manufactured by Daicel Corporation, functional group number: 4, weight average molecular weight: 1000) A1-2: EBECRYL7100 (manufactured by Daicel Corporation, functional group number: 2, weight average molecular weight: 400) A1-3: CN371 (manufactured by Sartmer, functional group number: 2, weight average molecular weight: 1600)

[0097] (Other polymerizable compounds (A2)) A2-1: Tripropylene glycol diacrylate (TPGDA) A2-2: Polyethylene glycol #600 diacrylate (PEGDA) A2-3: 3PO-modified trimethylolpropane triacrylate (3PO-TMPTA) A2-4: 3EO modified trimethylolpropane triacrylate (3EO-TMPTA)

[0098] (Photopolymerization initiator (B1)) B1-1: Ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad TPO-L (IGM Resins))

[0099] (Photopolymerization initiator (B2)) B2-1: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819 (IGM Resins)) B2-2: Diphenyl(2,4,6-trimethylbenzoyl)phenylphosphine oxide (DAROCURE TPO (BASF))

[0100] (Other photopolymerization initiators (B3)) B3-1: SPEEDCURE ITX (Lambson)

[0101] (Gelling agent (C)) Distearyl ketone (Kao Corporation)

[0102] The above materials were mixed in the ratios shown in Tables 1 to 3 and thoroughly mixed using a triple roll mill, then filtered through a 30 μm polypropylene pleated filter (manufactured by ROKI TECHNO Co., Ltd.) to obtain inks 1 to 19.

[0103] [Table 1]

[0104] [Table 2]

[0105] [Table 3]

[0106] 2. Evaluation The inks 1 to 19 prepared above were evaluated as follows.

[0107] 2-1. Resistance to bending and cracking Coating weight 9g / m 2 After leaving the 4 cm x 4 cm solid image in an environment of 25°C and 60% RH for 24 hours, the image was folded in half lengthwise so that the surface on which the solid image was formed formed a peak and creases were formed in the solid image of each color, and the degree of cracking in the image was evaluated. A: No cracks are observed or almost no cracks are observed. B: Cracks are observed in some areas C: Long cracks are observed. D: There are almost no cracks.

[0108] 2-2. Peeling off the cut surface A solid image formed on a recording medium (OK topcoat) was cut using a press cutter, Nichiban Cellotape (registered trademark) was applied to the cut surface, and the tape was then moved back and forth while applying a load from above with a finger, and the degree of peeling was evaluated visually. A: No adhesion of the peeled part to the tape side is observed, or adhesion of the peeled part only of the cut surface is observed to the tape side. B: A small amount of peeling is observed near the cut surface even on the image surface. C: Peeling is observed on the image surface away from the cut surface. D: Most of the tape comes off.

[0109] 2-3. Nail scraping The surface of a solid image formed on a recording medium (OK topcoat) was rubbed with a pseudo-nail (molded acrylic piece) for 30 seconds while applying a load of 250 g, and the degree of peeling was visually evaluated. A: No peeling was observed at all. B: Small areas may peel off. C: Peeled off, but most of the rubbed area remains. D: Almost the entire rubbed area peels off.

[0110] 2-4. Paper surface rubbing The solid image surface formed on the recording medium (OK top coat) was subjected to 500g / cm 2 A load of 1000 g was applied, and the ink was reciprocated 30 times, after which the degree of transfer to the paper surface was visually evaluated. A: No color transfer is observed, or almost no color transfer is observed. B: Color transfer can be faintly seen in some areas. C: Color transfer is visible to the naked eye. D: It is clearly visible that the color has transferred to the entire rubbed paper.

[0111] 2-5. Glossiness The density gradation patch images formed had a dot ratio of 20%, 50%, 70%, and 100% in an area of ​​2 cm x 2 cm. The gloss and gloss difference between the formed image area and the unprinted area (white area) of the recording medium were visually observed, and the gloss uniformity was evaluated according to the following criteria. A: In images with all dot rates, no difference in gloss was observed between the density gradation patch image and the unprinted part of the recording medium. B: For all dot ratio images, there is almost no discernible difference in gloss between the density gradation patch image and the unprinted area of ​​the recording medium. C: In some dot rate images, there is a slight difference in gloss between the density gradation patch image and the unprinted part of the recording medium, but the quality is within the range of practical acceptability. D: In images of all dot rates, a difference in gloss between the density gradation patch image and the unprinted part of the recording medium is observed, making the image unnatural or unsuitable for practical use.

[0112] 2-6. Blooming A 5 cm×5 cm solid image formed on a recording medium (OK top coat) was stored for one month in an environment at 40° C. After storage, the image was visually observed and evaluated for blooming according to the following criteria. A: No deposits are observed on the image surface. B: Almost no precipitate is observed on the image surface. C: A thin precipitate is present on the image surface and can be visually confirmed. D: The image surface is covered with a powder-like substance, which can be clearly seen with the naked eye.

[0113] The evaluation results are shown in Tables 4 to 6.

[0114] [Table 4]

[0115] [Table 5]

[0116] [Table 6]

[0117] As shown in Tables 4 to 6, Inks 1 to 15, which contain an amine-modified polymerizable compound (A1), a photopolymerization initiator (B1) which is ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and a gelling agent (C), had high abrasion resistance and also had improved resistance to fold cracking of the cured film. [Industrial Applicability]

[0118] According to the present invention, it is possible to produce a cured product that has both high abrasion resistance and fold crack resistance.

Claims

1. The composition comprises a polymerizable compound (A) that polymerizes when irradiated with actinic rays, a photopolymerization initiator (B), and a gelling agent (C), The polymerizable compound (A) includes an amine-modified polymerizable compound (A1), The photopolymerization initiator (B) contains ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide. Actinic radiation curing inkjet ink.

2. The content of the photopolymerization initiator (B) is 3% by mass or more and 10% by mass or less with respect to the total mass of the ink-jet ink. The actinic ray curable ink-jet ink according to claim 1 .

3. the content of the amine-modified polymerizable compound (A1) is more than 0% by mass and 20% by mass or less with respect to the total mass of the inkjet ink; The actinic ray curable ink-jet ink according to claim 1 .

4. a ratio (A1 / B) of the content of the amine-modified polymerizable compound (A1) to the content of the photopolymerization initiator (B) is greater than 0 and less than or equal to 8; The actinic ray curable ink-jet ink according to claim 1 .

5. the ratio (A1 / B) of the content of the amine-modified polymerizable compound (A1) to the content of the photopolymerization initiator (B) is greater than 0 and less than or equal to 2; The actinic ray curable ink-jet ink according to claim 1 .

6. The content of the gelling agent (C) is 0.5% by mass or more and 10% by mass or less with respect to the total mass of the ink-jet ink. The actinic ray curable ink-jet ink according to claim 1 .

7. The photopolymerization initiator (B) contains bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide or diphenyl(2,4,6-trimethylbenzoyl)phenylphosphine oxide. The actinic ray curable ink-jet ink according to claim 1 .

8. applying the inkjet ink of any one of claims 1 to 7 to a substrate; irradiating the applied ink-jet ink with actinic radiation; The method for producing a cured film comprising the steps of:

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