Method for producing active energy ray curable ink and printed matter

Abstract

To provide an active energy-ray curable ink that has excellent adhesiveness to various base materials including a plastic base material, even when a tetrahydrofurfuryl (meth)acrylate or tetrahydrofurfuryl alcohol is not contained or a content thereof is slight.SOLUTION: The present invention relates to an active energy-ray curable ink including: a polymerizable compound (A) containing a compound (a) having a structure shown by the following general formula (1) and a polymerizable unsaturated double bond, in which a content ratio of a compound (c) having a structure shown by the following chemical formula (2) to a total amount of the polymerizable compound (A) is 0 to 0.2 mass%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an actinic ray-curable ink that can be used in the production of various printed materials. [Background technology]

[0002] 2. Description of the Related Art Active energy ray-curable inks are superior in curing and drying properties compared to other inks, and are therefore used for printing on a variety of recording media including, for example, plastic films.

[0003] Known examples of the actinic energy ray-curable ink include ink compositions that contain a colorant, a radical polymerization initiator having a specific structure, and a radical polymerizable compound such as tetrahydrofurfuryl acrylate (see, for example, Patent Document 1).

[0004] However, in recent years, tetrahydrofurfuryl acrylate may contain small amounts of tetrahydrofurfuryl alcohol as an impurity or decomposition product, which has been a concern due to its impact on the human body, including on reproductive ability, and therefore the industry has tended to shy away from the use of inks containing tetrahydrofurfuryl acrylate.

[0005] On the other hand, an ink that does not contain tetrahydrofurfuryl acrylate may cause a decrease in adhesion to plastic substrates.

[0006] For this reason, the industrial sector has been demanding the development of an active energy ray-curable ink that does not contain tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl alcohol, and the like, or that contains a reduced amount of these compounds, and that has excellent adhesion to plastic substrates. However, such an ink has not yet been developed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2012-201815 A Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide an active energy ray-curable ink that has excellent adhesion to various substrates including plastic substrates even when it does not contain tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl alcohol, etc., or when the content of such compounds is small. [Means for solving the problem]

[0009] The present inventors have solved the above-mentioned problems by providing an active energy ray-curable ink containing a polymerizable compound (A) including a compound (a) having a structure represented by the following general formula (1) and a polymerizable unsaturated double bond, wherein the content of a compound (c) having a structure represented by the following chemical formula (2) is 0 mass % to 0.2 mass % relative to the total amount of the polymerizable compound (A):

[0010] [ka]

[0011] [R in general formula (1)] 1 is an alkylene group having one or more carbon atoms, and R 2 is R 1 is an alkylene group having 1 or more carbon atoms, which may be the same as or different from R 3 is a hydrogen atom or an alkyl group, and n is an integer of 0 or more.

[0012] [ka] Effect of the Invention

[0013] The active energy ray-curable ink of the present invention, even if it does not contain tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl alcohol, or the like, or even if the content thereof is small, has excellent adhesion performance to plastic substrates and the like, and therefore can be suitably used, for example, in the production of printed matter using an inkjet recording device or the like. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The active energy ray-curable ink of the present invention is an active energy ray-curable ink containing a polymerizable compound (A) including a compound (a) having a structure represented by the following general formula (1) and a polymerizable unsaturated double bond, and is characterized in that the content of the compound (c) having a structure represented by the following chemical formula (2) is 0 mass % to 0.2 mass % relative to the total amount of the polymerizable compound (A):

[0015] [ka]

[0016] [R in general formula (1)] 1 is an alkylene group having one or more carbon atoms, and R 2 is R 1 is an alkylene group having 1 or more carbon atoms, which may be the same as or different from R 3 is a hydrogen atom or an alkyl group, and n is a natural number.

[0017] [ka]

[0018] The polymerizable compound (A) contains, as an essential component, a compound (a) having a structure represented by the general formula (1) and a polymerizable unsaturated double bond, and may contain a compound (b) other than the compound (a) as necessary.

[0019] As the compound (a), a compound having the structure represented by the general formula (1) and a polymerizable unsaturated double bond is used. This makes it possible to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates, even when the content of the compound (c) having the structure represented by the chemical formula (2) is 0% by mass to 0.2% by mass, preferably 0% by mass to 0.1% by mass, more preferably 0% by mass to 0.05% by mass, and particularly preferably 0% by mass, based on the total amount of the polymerizable compound (A).

[0020] R constituting the general formula (1) 1 and R 2 Examples of R include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, and an isobutylene group. 1 and R 2 may be the same or different. 1 and R 2 Among the above, R 1 and R 2 In order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates, it is more preferable that each of the above groups be an ethylene group.

[0021] R constituting the general formula (1) 3 Examples of R include a hydrogen atom and alkyl groups such as a methyl group, an ethyl group, and a butyl group. 3 is more preferably an ethyl group in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates.

[0022] In the general formula (1), n ​​is preferably an integer in the range of 0 to 20, more preferably in the range of 0 to 3, and is more preferably 1 in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates.

[0023] Specifically, the compound (a) may be methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, methoxytriethylene glycol (meth)acrylate, etc. Among them, the use of ethoxyethoxyethyl (meth)acrylate as the compound (a) is particularly preferred in obtaining an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates, even when the polymerizable compound (A) does not contain a compound (c) having a structure represented by the chemical formula (2) or the content ratio of the compound (c) to the entire polymerizable compound (A) is 0% by mass to 0.2% by mass, preferably 0% by mass to 0.1% by mass, more preferably 0% by mass to 0.05% by mass, and particularly preferably 0% by mass.

[0024] The compound (a) is preferably contained in an amount of 20% by mass to 40% by mass, and more preferably in an amount of 25% by mass to 35% by mass, based on the total amount of the polymerizable compound (A), in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates.

[0025] By using the polymerizable compound (A) containing the compound (a) having the structure represented by the general formula (1), even if the polymerizable compound (A) does not contain the compound (c) having the structure represented by the chemical formula (2) or the content ratio of the compound (c) to the entire polymerizable compound (A) is 0 mass % to 0.2 mass %, it is possible to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates.

[0026] Examples of the compound (c) having the structure represented by the chemical formula (2) include tetrahydrofurfuryl (meth)acrylate and tetrahydrofurfuryl alcohol, and the content thereof is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, more preferably 0% by mass to 0.05% by mass, and particularly preferably 0% by mass, based on the total amount of the polymerizable compound (A).

[0027] As the polymerizable compound (A), it is preferable to use one that contains, in addition to the compound (a), a compound (b) having a polymerizable unsaturated double bond other than the compound (a) as necessary.

[0028] The compound (b) used is preferably one having 1 to 6 polymerizable unsaturated double bonds, and more preferably one having 1 to 3 polymerizable unsaturated double bonds in order to obtain an ink having even better flexibility and adhesion to the plastic substrate.

[0029] The compound (b) is preferably used in an amount of 80% by mass to 95% by mass based on the total amount of the polymerizable compound (A) in order to obtain an ink having even better flexibility and adhesion to the plastic substrate or the like.

[0030] As the compound (b), for example, a compound (b-1) having a heterocyclic structure other than that of the above chemical formula (2), a compound (b-2) having an aliphatic cyclic structure, etc. can be used.

[0031] Examples of the compound (b-1) that can be used include caprolactone-modified tetrahydrofurfuryl acrylate, acryloylmorpholine, N-vinyl-2-caprolactam, N-vinylpyrrolidone, and N-acryloyloxyethylhexahydrophthalimide. Among them, the use of N-vinyl-2-caprolactam as the compound (b-1) is preferable in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates, even when the compound (c) having the structure represented by the chemical formula (2) is not present in the polymerizable compound (A) or the content of the compound (c) is 0% by mass to 0.2% by mass relative to the entire polymerizable compound (A).

[0032] In order to further improve the long-term storage stability of the ink of the present invention, the compound (b-1) is preferably used in the range of 1 mass % to 15 mass % relative to the total amount of the polymerizable compound (A), and it is more preferable to use it in the range of 5 mass % to 15 mass % in order to obtain an ink having excellent adhesion to various substrates including plastic substrates.

[0033] Furthermore, the compound (b-2) can be used in the production of printed matter having a level of chemical resistance that does not cause peeling of the coating film even when it comes into contact with a chemical such as alcohol, and is preferably used in combination with the compound (a) or the compound (b-1), etc., in order to obtain an active energy ray-curable ink having even better adhesion to various substrates including plastic substrates.

[0034] Examples of the compound (b-2) that can be used include tricyclodecane dimethanol di(meth)acrylate, adamantyl (meth)acrylate, cyclohexane dimethanol mono(meth)acrylate, cyclohexane dimethanol di(meth)acrylate, trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. Of these, the use of isobornyl (meth)acrylate is more preferable in terms of obtaining an ink that can be used in the production of printed matter having a printing coating film with excellent chemical resistance.

[0035] The compound (b-2) is preferably used in an amount of 5% by mass to 24% by mass based on the total amount of the polymerizable compound (A), and more preferably used in an amount of 5% by mass to 20% by mass in order to obtain an ink that can be used for producing printed matter having a printing coating film with better chemical resistance.

[0036] In addition, the ratio of the structure represented by general formula (1) in compound (a) to the aliphatic cyclic structure in compound (b-2) [structure represented by general formula (1) / aliphatic cyclic structure] is preferably in the range of 10 to 40.

[0037] The active energy ray-curable ink of the present invention may contain a photopolymerization initiator in addition to the polymerizable compound (A).

[0038] Examples of the photopolymerization initiator include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 1-hydroxy Cyclohexyl phenyl ketone, benzoin ethyl ether, benzil dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one and 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyl-diphenyl sulfide, and the like can be used.

[0039] As the photopolymerization initiator, it is preferable to use an acylphosphine oxide-based photopolymerization initiator among the above-mentioned.

[0040] In addition, when a UV-LED light source is used as the light source of the active energy rays, it is preferable to use, as the photopolymerization initiator, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl)-butan-1-one), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, or the like, which correspond to the wavelength of light emitted from the UV-LED light source.

[0041] The photopolymerization initiator is preferably used in combination with a sensitizer. As the sensitizer, for example, an amine that does not have reactivity with the polymerizable compound (A), such as trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, and 4,4'-bis(diethylamino)benzophenone, can be used.

[0042] The active energy ray-curable ink of the present invention may contain a colorant, if necessary, in addition to the polymerizable compound (A) and the photopolymerization initiator.

[0043] The colorant may be, for example, a pigment or a dye, and examples of the pigment include a phthalocyanine pigment used in cyan ink, a quinacridone pigment used in magenta ink, an azo pigment used in yellow ink, carbon black used in black ink, and a white pigment usable in white ink.

[0044] Examples of phthalocyanine pigments used in the cyan ink include CI Pigment Blue 1, 2, 3, 15:3, 15:4, 16:6, 16, 17:1, 75, and 79.

[0045] Examples of quinacridone pigments used in magenta inks include CI Pigment Red 122, CI Pigment Red 202, CI Pigment Red 209, CI Pigment Violet 19, and the like.

[0046] Azo pigments used in the yellow ink include monoazo and disazo pigments such as, for example, CI Pigment Yellow 120, 151, 154, 175, 180, 181, 1, 65, 73, 74, 116, 12, 13, 17, 81, 83, 150, 155, 214, 128, and the like.

[0047] Examples of carbon black used in black inks include Mitsubishi Chemical's No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, and No. 2200B; Columbia's Raven 5750, 5250, 5000, 3500, 1255, and 700; Cabot's Regal 400R, 330R, 660R, Mogul L, 700, Monarch 800, 880, 900, 1000, 1100, 1300, and 1400; and Degussa's Color Black FW1, FW2, FW2V, FW18, FW200, ColorBlack S150, S160, S170, Printex Examples include 35, 35 U, 35 V, 140U, Special Black 6, 5, 4A, and 4.

[0048] The white pigment that can be used in the white ink is not particularly limited, and any known inorganic white pigment can be used. Examples of the inorganic white pigment include sulfates or carbonates of alkaline earth metals, silicas such as fine powdered silicic acid and synthetic silicates, calcium silicate, alumina, alumina hydrate, titanium oxide, zinc oxide, talc, clay, etc. As the inorganic white pigment, the above-mentioned silicas and the like can also be used whose surfaces have been treated by various surface treatment methods.

[0049] The average particle size of the pigment is preferably in the range of 10 to 300 nm, and more preferably 50 to 200 nm.

[0050] In order to obtain sufficient image density and lightfastness of the printed image, the pigment is preferably contained in the range of 1 to 20% by mass, more preferably in the range of 1 to 10% by mass, and most preferably in the range of 1 to 5% by mass, based on the total amount of each ink. Also, it is preferable that the pigment concentration of the magenta ink is higher than that of the other color inks. Specifically, it is preferable that the pigment concentration of the magenta ink is 1.2 times or more, and more preferably 1.2 to 4 times, that of the other color inks.

[0051] The titanium oxide preferably has an average particle size of 100 to 500 nm, and more preferably has an average particle size of 150 nm to 400 nm in order to obtain an ink having even better ejection stability and high color development of printed images.

[0052] The pigment may be used in combination with a pigment dispersant, a pigment derivative (synergist), or the like, for the purpose of enhancing the dispersion stability with respect to the polymerizable compound (A) or the like.

[0053] Examples of the pigment dispersant that can be used include Ajisper PB821, PB822, and PB817 manufactured by Ajinomoto Fine-Techno Co., Ltd.; Solspers 24000GR, 32000, 33000, and 39000 manufactured by Avecia Corporation; and Disparlon DA-703-50, DA-705, and DA-725 manufactured by Kusumoto Chemicals Co., Ltd.

[0054] The amount of the pigment dispersant used is preferably in the range of 10 to 100% by mass relative to the pigment, and more preferably in the range of 20 to 60% by mass in order to obtain an ink having even better ejection stability and pigment dispersibility. Examples of the pigment derivative include sulfonic acid derivatives of pigments.

[0055] In addition to the above-mentioned components, the active energy ray curable ink of the present invention may contain, if necessary, a polymerization inhibitor such as hydroquinone, methoquinone, di-t-butylhydroquinone, p-methoxyphenol, butylhydroxytoluene, nitrosamine salt, etc. The polymerization inhibitor may be used in an amount of 0.01% by mass to 2% by mass based on the total amount of the ink of the present invention.

[0056] The active energy ray curable ink of the present invention may contain a sensitizer such as trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, and 4,4'-bis(diethylamino)benzophenone.

[0057] As the active energy ray-curable ink of the present invention, one containing a non-reactive resin such as an acrylic resin, an epoxy resin, a terpene phenol resin, or a rosin ester can be used in order to further improve adhesion to a substrate such as a plastic substrate.

[0058] The active energy ray-curable ink of the present invention preferably has a viscosity at 25°C in the range of 3 mPa·sec to 30 mPa·sec, and more preferably in the range of 5 mPa·sec to 20 mPa·sec in order to achieve stable inkjet ejection.

[0059] The active energy ray-curable ink of the present invention can be produced, for example, by dispersing the pigment using a normal dispersing machine such as a bead mill, a mixture of the polymerizable compound (A), and optionally a pigment, a pigment dispersant, and a resin, and then adding a photopolymerization initiator and, optionally, additives such as a polymerization inhibitor, a sensitizer, and a surface tension adjuster, followed by stirring and dissolving.

[0060] The active energy ray-curable ink can also be produced by first producing a high-concentration pigment dispersion (mill base) containing a pigment, a pigment dispersant, a resin, and the like using a normal dispersing machine such as a bead mill, and then supplying a photopolymerization initiator, a polymerizable compound (A), additives, and the like, and stirring and mixing the resulting mixture.

[0061] As the dispersing machine, in addition to a bead mill, various known and commonly used dispersing machines such as an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a Dyno Mill, a Dispermat, an SC Mill, or a Nanomizer can be used.

[0062] The active energy ray curable ink of the present invention is cured by irradiation with active energy rays, preferably ultraviolet rays, etc. As the light source for ultraviolet rays, etc., light sources generally used for active energy ray curable inkjet recording inks, such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low pressure mercury lamps, high pressure mercury lamps, UV-LED lamps, etc., can be used.

[0063] The active energy ray curable ink of the present invention can be suitably used exclusively for printing by an inkjet recording method using an inkjet recording apparatus.

[0064] Any of the conventional inkjet recording methods can be used, including a method of ejecting droplets by utilizing the vibration of a piezoelectric element (a recording method using an inkjet head that forms ink droplets by the mechanical deformation of an electrostrictive element) and a method that utilizes thermal energy.

[0065] The active energy ray curable ink is ejected onto a substrate, which is a recording medium, using an inkjet recording device, and cured by irradiation with active energy rays, thereby producing a printed matter. Examples of the printed matter include advertisements, signs, guide boards, and promotional item printing.

[0066] The active energy ray-curable ink of the present invention has excellent adhesion to various substrates that are recording media, and can therefore be easily printed on the surface of a substrate having a curved surface or an irregular shape with projections and recesses.

[0067] The substrate may be, for example, a plastic substrate, and examples of the plastic substrate include substrates made of ABS (acrylonitrile butadiene styrene) resin, PVC (polyvinyl chloride) / ABS resin, PA (polyamide) / ABS resin, PC (polycarbonate) / ABS resin, ABS-based polymer alloys such as PBT (polybutylene terephthalate) / ABS, AAS (acrylonitrile acrylic rubber styrene) resin, AS (acrylonitrile styrene) resin, AES (acrylonitrile ethylene rubber styrene) resin, MS ((meth)acrylic acid ester styrene)-based resin, PC (polycarbonate)-based resin, acrylic resin, methacrylic resin, PP (polypropylene)-based resin, and the like, which are used as general-purpose injection molding plastics.

[0068] As the plastic substrate, for example, a thermoplastic resin film used for packaging materials can also be used.

[0069] Examples of the thermoplastic resin film include those generally used as thermoplastic resin films for food packaging, such as polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyolefin films such as polyethylene film (LLDPE: low density polyethylene film, HDPE: high density polyethylene film) and polypropylene film (CPP: non-oriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. As the thermoplastic resin film, those that have been subjected to a stretching treatment such as uniaxial stretching or biaxial stretching, or those whose surfaces have been subjected to a flame treatment or corona discharge treatment, etc., can also be used. EXAMPLES

[0070] The present invention will now be described in more detail with reference to examples.

[0071] [Example of pigment dispersion preparation] Preparation example of cyan pigment dispersion (1) 10 parts by mass of Fastgen Blue TGR-G (phthalocyanine pigment CI Pigment Blue 15:4, manufactured by DIC Corporation), 4.5 parts by mass of Solspers 32000 (polymeric pigment dispersant, manufactured by Lubrizol Corporation), and 85.5 parts by mass of Light Acrylate PO-A (phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.) were mixed and stirred for 1 hour with a stirrer, and then treated for 2 hours with a bead mill to obtain a cyan pigment dispersion (1).

[0072] [Ink preparation example] According to the compositions in Tables 1 and 2, active energy ray-curable inkjet recording inks were prepared. Specifically, MIRAMER M3130 (ethylene oxide (EO)-modified trimethylolpropane triacrylate manufactured by MIWON), MIRAMER M240 (ethylene oxide (EO)-modified bisphenol A diacrylate manufactured by MIWON), V-190 (ethoxyethoxyethyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.), IBXA (isobornyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.), V-CAP (N-vinyl-2-caprolactam manufactured by ISP), Light Acrylate POA (phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd.), a tetrahydrofurfuryl acrylate composition containing a trace amount of tetrahydrofurfuryl alcohol, and KF-54 (polysiloxane manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a container and mixed with stirring, and then Irgacure 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF), Irgacure.TPO (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF) and Irgacure.TPO (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF) were added to the container and mixed with stirring. 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) and Kayacure DETX-S (diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd.) were added and dissolved by mixing at a temperature of 60° C. for 30 minutes.

[0073] Next, the cyan pigment dispersion (1) was added, and the mixture was stirred and mixed for 10 minutes to obtain cyan inks (C1 to C3).

[0074] [Adhesion to substrate] The active energy ray curable inkjet recording ink was applied to a polycarbonate plate (Asahi Glass Co., Ltd., Lexan, thickness 1 mm, PC) and a vinyl chloride sheet (DIC Corporation, vinyl chloride sheet, PVC) to a thickness of 10 μm using a spin coater, and then was irradiated with an LED irradiation device (emission wavelength: 385 nm, peak intensity: 500 mW / cm) equipped with a stage movement device manufactured by Hamamatsu Photonics K.K. 2 ) was used and the coating film was irradiated until the tack on the surface was removed (until it became tack-free).

[0075] The resulting cured coating was cut into 25 5 x 5 squares with a utility knife, then cellophane tape manufactured by Nichiban Co., Ltd. was applied and rubbed with a fingernail about 10 times. The tape was peeled off vigorously at a peeling speed of about 1 cm / sec, and the number of squares remaining on the coating was counted.

[0076] Evaluation criteria ○: 20 or more squares of coating film remain on the surface of the polycarbonate plate or polyvinyl chloride sheet △: The number of squares of the coating remaining on the surface of the polycarbonate plate or polyvinyl chloride sheet is 15 or more and less than 20. ×: The number of squares of coating remaining on the surface of the polycarbonate plate or polyvinyl chloride sheet is less than 15.

[0077] [Solvent resistance] The active energy ray curable inkjet recording ink was applied to a polycarbonate plate (Asahi Glass Co., Ltd., Lexan, thickness 1 mm, PC) to a thickness of 10 μm using a spin coater, and then the ink was irradiated with an LED irradiation device (emission wavelength: 385 nm, peak intensity: 500 mW / cm) equipped with a stage movement device manufactured by Hamamatsu Photonics K.K. 2 ) was used and the coating film was irradiated until the tack on the surface was removed (until it became tack-free).

[0078] A cotton swab soaked in a mixture of ethanol and water (70% by mass of ethanol) was placed on the resulting cured coating film, and the film was rubbed left and right 10 times over a width of about 2 cm. Films that left no marks on the surface were evaluated as "○", and films that left marks were evaluated as "×".

[0079] [Environmental friendliness] Substances for which there was concern about the effects on the human body (reproductive toxicity) derived from tetrahydrofurfuryl alcohol were rated as "present," and substances for which there was thought to be no concern about the effects on the human body (reproductive toxicity) derived from tetrahydrofurfuryl alcohol were rated as "absent."

[0080] [Table 1]

[0081] [Table 2]

[0082] The abbreviations in Tables 1 and 2 refer to the following compounds. V-190: Osaka Organic Chemical Industry Co., Ltd. Ethoxyethoxyethyl acrylate M3130: MIWON ethylene oxide (EO) modified trimethylolpropane triacrylate M240: MIWON ethylene oxide (EO) modified bisphenol A diacrylate POA: Phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd. V-CAP: N-vinyl-2-caprolactam manufactured by ISP IBXA: Isobornyl acrylate manufactured by Osaka Organic Chemical Industry Ltd. THFA: Tetrahydrofurfuryl acrylate composition containing a trace amount of tetrahydrofurfuryl alcohol KF-54: Polysiloxane manufactured by Shin-Etsu Chemical Co., Ltd. Irgacure819: BASF Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide IrgacureTPO: BASF 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide KayacureDETX-S: Diethylthioxanthone manufactured by Nippon Kayaku Co., Ltd.

Claims

1. The present invention provides an active energy ray-curable ink containing a polymerizable compound (A) including ethoxyethoxyethyl acrylate, which is a compound (a) having a structure represented by the following general formula (1) and a polymerizable unsaturated double bond, N-vinyl-2-caprolactam, which is a compound (b-1) having a heterocyclic structure other than the following chemical formula (2), and isobornyl (meth)acrylate, which is a compound (b-2) having an aliphatic cyclic structure, and an acylphosphine oxide-based photopolymerization initiator, wherein the ethoxyethoxyethyl acrylate is a compound having a structure represented by the following general formula (1) and a polymerizable unsaturated double bond, and the polymerizable compound (A) includes an acylphosphine oxide-based photopolymerization initiator, the compound (b-1) is contained in an amount of 5 to 12 parts by mass relative to 100 parts by mass of the active energy ray curable ink, the compound (b-2) is contained in an amount of 5 to 21 parts by mass relative to 100 parts by mass of the active energy ray curable ink, and a content of tetrahydrofurfuryl acrylate, which is compound (c) having a structure represented by the following chemical formula (2), is 0 part by mass relative to 100 parts by mass of the active energy ray curable ink. [R in formula (1)] １ is an alkylene group having one or more carbon atoms, R ２ is R １ is an alkylene group having 1 or more carbon atoms, which may be the same as or different from ３ is a hydrogen atom or an alkyl group, and n is an integer of 0 or more.

2. 2. The active energy ray-curable ink according to claim 1, wherein the polymerizable compound (A) contains the compound (a) in an amount of from 20% by mass to 40% by mass with respect to the entire polymerizable compound (A).

3. 3. The active energy ray-curable ink according to claim 1, wherein the compound (b-1) is contained in an amount of 1% by mass to 15% by mass based on the total amount of the polymerizable compound (A).

4. The active energy ray-curable ink according to any one of claims 1 to 3, wherein the compound (b-2) is contained in an amount of 1 mass % to 24 mass % based on the total amount of the polymerizable compound (A).

5. The active energy ray-curable ink according to claim 1 , further comprising ethylene oxide-modified trimethylolpropane triacrylate and ethylene oxide-modified bisphenol A diacrylate.

6. 6. The active energy ray-curable ink according to claim 1, which has a viscosity at 25° C. in the range of 5 to 30 mPa·sec.

7. The active energy ray-curable ink according to any one of claims 1 to 6, which is used for printing on a recording medium which is polycarbonate or vinyl chloride.

8. A method for producing a printed matter, comprising ejecting the active energy ray-curable ink according to claim 7 onto a recording medium made of polycarbonate or vinyl chloride using an inkjet recording device, and curing the ink by irradiating the ink with active energy rays using a UV-LED lamp.

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