Active energy ray-curable ink and method for producing printed matter

Abstract

To provide an actinic-ray-curable ink which has excellent adhesiveness to various substrates including plastic substrates even when containing none of tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl alcohol and the like or containing such compounds only in small amounts.SOLUTION: The problem is solved with an actinic-ray-curable ink characterized by containing a polymerizable compound (A) having a specific structure.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Active energy ray curable inks are used for printing on various recording media such as plastic films because they are superior in curability and drying property compared to other inks.

[0003] As the active energy ray curable ink, for example, an ink composition containing a colorant, a radical polymerization initiator having a specific structure, and a radical polymerizable compound such as tetrahydrofurfuryl acrylate is known (see, for example, Patent Document 1).

[0004] However, in recent years, tetrahydrofurfuryl acrylate may slightly contain tetrahydrofurfuryl alcohol, which raises concerns about its effects on the human body such as skin irritation, as impurities or decomposition products. Therefore, in the industry, there is a tendency to avoid using inks containing tetrahydrofurfuryl acrylate.

[0005] On the other hand, inks that do not contain tetrahydrofurfuryl acrylate may sometimes cause a decrease in adhesion performance to plastic substrates.

[0006] Therefore, although the industry demands the development of active energy ray curable inks that do not contain tetrahydrofurfuryl (meth) acrylate or tetrahydrofurfuryl alcohol, or have a reduced content thereof, and have excellent adhesion performance to plastic substrates, the fact is that they have not yet been found.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS 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 having excellent adhesion performance to various substrates including a plastic substrate even when it does not contain tetrahydrofurfuryl (meth) acrylate, tetrahydrofurfuryl alcohol, etc., or when the content thereof is small.

MEANS FOR SOLVING THE PROBLEMS

[0009] The present inventor has solved the above problems by an active energy ray-curable ink containing a polymerizable compound (A) containing at least one selected from the group consisting of a compound (a2) having a structure represented by the following general formula (2) and a compound (a3) having a structure represented by the general formula (3).

EFFECTS OF THE INVENTION

[0010] The active energy ray-curable ink of the present invention does not contain tetrahydrofurfuryl (meth) acrylate, tetrahydrofurfuryl alcohol, etc., or even when the content thereof is small, it has excellent adhesion performance to a plastic substrate or the like, and thus can be suitably used, for example, in a production scene of a printed matter using an inkjet recording apparatus or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]

Figure 1

MODE FOR CARRYING OUT THE INVENTION

[0012] The active energy ray-curable ink of the present invention contains a polymerizable compound (A) containing at least one selected from the group consisting of a compound (a2) having a structure represented by the following general formula (2) and a compound (a3) having a structure represented by the general formula (3).

[0013]

Chemical formula

[0014] (In general formula (2), R 1 and R 2 each independently represent a hydrogen atom or an alkyl group, and R 3 represents a hydrogen atom or an alkyl group. In general formula (3), R 3 represents a hydrogen atom or an alkyl group.)

[0015] The compounds (a2) and (a3) that can be used in the polymerizable compound (A) will be described. As the compound (a2), those having a structure represented by the following general formula (2) are used, and as the compound (a3), those having a structure represented by the following general formula (3) are used.

[0016]

Chemical formula

[0017] (In general formula (2), R 1 and R 2 each independently represent a hydrogen atom or an alkyl group, and R 3 represents a hydrogen atom or an alkyl group. In general formula (3), R 3 represents a hydrogen atom or an alkyl group.)

[0018] The compounds (a2) and (a3) have a high anchoring effect on a substrate as a recording medium, and exhibit an excellent adhesion effect on substrates such as plastic substrates.

[0019] As the compound (a2) and the compound (a3), compounds having the structures represented by the above general formula (2) or general formula (3) can be used alone or in combination of two or more.

[0020] As the compound (a2), it is preferable to use a compound having the structure represented by the general formula (2) in order to further improve the adhesion of the ink to the base material. In the general formula (2), R 1 and R 2 are each independently an alkyl group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, and it is more preferable to use a compound in which R 3 is a hydrogen atom.

[0021] As the compound (a2), R 1 in the general formula (2) is a methyl group, R 2 is an ethyl group, R 3 is a hydrogen atom, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, or R 1 is a methyl group, R 2 is an isopropyl group, R 3 is a hydrogen atom or a methyl group, or a compound in which R 1 and R 2 are methyl groups and R 3 is a hydrogen atom or a methyl group can be used. Among them, it is particularly preferable to use (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate in order to obtain an ink having excellent adhesion to the base material.

[0022] The compound (a2) is preferably contained in the range of 5% by mass to 40% by mass, and more preferably contained in the range of 8% by mass to 30% 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 base materials including plastic base materials.

[0023] Further, as the compound (a3), a compound represented by the general formula (3) can be used.

[0024] The compound (a3) is preferably contained in the range of 5% by mass to 40% by mass, more preferably 8% by mass to 30% 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] As the polymerizable compound (A), by using one or both of the compound (a2) and the compound (a3), the compound (c) having the structure represented by the following chemical formula (5) is not contained in the polymerizable compound (A), or the content ratio of the compound (c) with respect to the total amount of the polymerizable compound (A) is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, and even more preferably 0% by mass to 0.05% by mass. Even in this case, an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates can be obtained.

[0026] As the polymerizable compound (A), it is preferable to use one in which the compound (a2) and the compound (a3) are contained in a total range of 5% by mass to 40% by mass with respect to 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.

[0027] As the polymerizable compound (A), in addition to the compound (a2) and the compound (a3), those appropriately selected and combined from the compounds (a1), (a4), and (a5) described later can be used as needed.

[0028] The compound (a1) that can be used in the polymerizable compound (A) will be described.

[0029] As the compound (a1), those having a structure represented by the following general formula (1) and a polymerizable unsaturated double bond can be used.

[0030] [Chemical formula]

[0031] [In the general formula (1), R 1 is an alkylene group having 1 or more carbon atoms, and R 2 is an alkylene group having 1 or more carbon atoms which may be the same as or different from R 1 , R 3 is a hydrogen atom or an alkyl group, and n is an integer of 0 or more.]

[0032] Examples of R 1 and R 2 which constitute the general formula (1) include, for example, a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, and the like. R 1 and R 2 may be the same or different from each other. Among the above, for R 1 and R 2 , it is more preferable that both R 1 and R 2 are ethylene groups in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate.

[0033] Examples of R 3 which constitutes the general formula (1) include an alkyl group such as a hydrogen atom, a methyl group, an ethyl group, a butyl group, and the like. Among them, it is more preferable that R 3 is an ethyl group in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate.

[0034] As n which constitutes the general formula (1), it is preferably an integer in the range of 0 to 20, more preferably in the range of 0 to 3, and most preferably 1 in order to obtain an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate.

[0035] As the compound (a1), specifically, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, diethylene glycol monobutyl ether (meth) acrylate, methoxytriethylene glycol (meth) acrylate, etc. can be used. Among them, as the compound (a1), using ethoxyethoxyethyl (meth) acrylate is particularly preferred for obtaining an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate, even when the compound (c) having the structure represented by the following chemical formula (5) is not contained in the polymerizable compound (A), or the content ratio of the compound (c) to the whole polymerizable compound (A) is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, still more preferably 0% by mass to 0.05% by mass, and particularly preferably 0% by mass.

[0036] The compound (a1) is preferably contained in the range of 20% by mass to 40% by mass with respect to the whole polymerizable compound (A), and being contained in the range of 25% by mass to 35% by mass is preferred for obtaining an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate.

[0037] As the polymerizable compound (A), by using a compound containing the compound (a1) having the structure represented by the general formula (1), even when the content ratio of the compound (c) having the structure represented by the following chemical formula (5) is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, still more preferably 0% by mass to 0.05% by mass, and particularly preferably 0% by mass with respect to the whole polymerizable compound (A), an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate can be obtained.

[0038]

Chemical formula

[0039] Next, the compound (a4) that can be used in the polymerizable compound (A) will be described.

[0040] As the compound (a4), a compound (a4) represented by the following general formula (4) is used.

[0041] [Chemical Formula]

[0042] (In general formula (4), R 1 , R 2 and R 3 each independently represent a hydrogen atom or an alkyl group, and X 1 represents a single bond or an alkylene group.)

[0043] Examples of the alkyl group include a methyl group and an ethyl group. Specific examples of X 1 include a methylene group and an ethylene group.

[0044] As the compound (a4) represented by the general formula (4), it is preferable to use a compound in which R 1 , R 2 , and R 3 in the general formula (4) are hydrogen atoms in terms of achieving an adhesion effect to the plastic substrate.

[0045] Specifically, it is preferable to use cyclic trimethylolpropane formal acrylate as the compound (a4) represented by the general formula (4).

[0046] The compound (a4) is preferably contained in the range of 5% by mass to 40% by mass, and more preferably in the range of 8% by mass to 30% 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 a plastic substrate.

[0047] By using a polymerizable compound (A) containing the compound (a4), the polymerizable compound (A) does not contain a compound (c) having a structure represented by the following chemical formula (5), or even when the content ratio of the compound (c) to the whole polymerizable compound (A) is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, and still more preferably 0% by mass to 0.05% by mass, an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate can be obtained.

[0048] Next, the 2-allyloxymethyl acrylate (a5) that can be used for the polymerizable compound (A) will be described.

[0049] As the 2-allyloxymethyl acrylate (a5), a compound represented by the following general formula (6) is used.

[0050]

Chemical formula

[0051] (In the general formula (6), R 1 represents an alkyl group.)

[0052] As the 2-allyloxymethyl acrylate (a5), examples of the compound in which R 1 in the general formula (6) is an alkyl group having 1 to 3 carbon atoms include compounds in which R 1 is a methyl group. Using methyl 2-allyloxymethyl acrylate is more preferable for obtaining an active energy ray-curable ink having excellent adhesion to various substrates including a plastic substrate.

[0053] When the active energy ray-curable ink containing the alkyl 2-allyloxymethylacrylate (a5) adheres to and cures on the surface of a substrate as the recording medium, a heterocyclic structure is formed. As a result, an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates can be obtained.

[0054] The alkyl 2-allyloxymethylacrylate (a5) is preferably contained in the range of 5% by mass to 40% by mass, more preferably 8% by mass to 30% 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.

[0055] By using a polymerizable compound (A) containing the alkyl 2-allyloxymethylacrylate (a5), the polymerizable compound (A) does not contain a compound (c) having a structure represented by the following chemical formula (5), or the content ratio of the compound (c) to the total amount of the polymerizable compound (A) is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, and even more preferably 0% by mass to 0.05% by mass. Even in such a case, an active energy ray-curable ink having excellent adhesion to various substrates including plastic substrates can be obtained.

[0056] Here, the compound (c) having a structure represented by the chemical formula (5) will be described.

[0057]

Chemical formula

[0058] Examples of the compound (c) having a structure represented by the chemical formula (5) include tetrahydrofurfuryl (meth)acrylate and tetrahydrofurfuryl alcohol.

[0059] As the polymerizable compound (A) used in the present invention, those containing the compound (c) may be used, but the content of the compound (c) is preferably 0% by mass to 0.2% by mass, more preferably 0% by mass to 0.1% by mass, still more preferably 0% by mass to 0.05% by mass, and particularly preferably 0% by mass with respect to the entire polymerizable compound (A).

[0060] As the polymerizable compound (A), the compound (a2) or the compound (a3) is used as an essential component, and further one or more are selected from the compound (a1), the compound (a4), and alkyl 2-allyloxymethylacrylate (a5) and used in combination, which is preferable for achieving the substrate adhesion effect. In particular, as the polymerizable compound (A), it is preferable to use the compound (a1), the compound (a2), the compound (a4), and alkyl 2-allyloxymethylacrylate (a5) in combination. Using the compound (a2), the compound (a4), and alkyl 2-allyloxymethylacrylate (a5) in combination is preferable for obtaining an active energy ray-curable ink that achieves both better adhesion to various substrates including plastic substrates and reduction of the tackiness of the printed surface (coating film).

[0061] In addition, as the polymerizable compound (A), in addition to the compound (a1), the compound (a2), the compound (a3), the compound (a4), and alkyl 2-allyloxymethylacrylate (a5), those containing a compound (b) other than the compound (a1), the compound (a2), the compound (a3), the compound (a4), and alkyl 2-allyloxymethylacrylate (a5) can be used as needed.

[0062] As the compound (b), a compound having a polymerizable unsaturated double bond can be used, and it is preferable to use a compound having a polymerizable unsaturated double bond in the range of 1 to 6, and it is more preferable to use a compound having a polymerizable unsaturated double bond in the range of 1 to 3 in order to obtain an ink that is more excellent in terms of flexibility and adhesion to the plastic substrate and the like.

[0063] It is preferable to use the compound (b) in the range of 50% by mass to 90% by mass based on the total amount of the polymerizable compound (A) in order to obtain an ink that is even more excellent in terms of flexibility and adhesion to the plastic substrate and the like.

[0064] As the compound (b), for example, a compound (b-1) having a heterocyclic structure other than the chemical formula (5), a compound (b-2) having an aliphatic cyclic structure, etc. can be used.

[0065] As the compound (b-1), for example, caprolactone-modified tetrahydrofurfuryl acrylate, acryloylmorpholine, N-vinyl-2-caprolactam, N-vinylpyrrolidone, N-acryloyloxyethylhexahydrophthalimide, etc. can be used. Among them, as the compound (b-1), it is preferable to use N-vinyl-2-caprolactam, even when the compound (c) having the structure represented by the chemical formula (5) does not exist in the polymerizable compound (A), or when the content ratio of the compound (c) is 0% by mass to 0.2% 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.

[0066] The compound (b-1) is preferably used in the range of 1% by mass to 15% by mass based on the total amount of the polymerizable compound (A) in order to further improve the long-term storage stability of the ink of the present invention, and it is more preferable to use it in the range of 5% by mass to 15% by mass in order to obtain an ink having excellent adhesion to various substrates including plastic substrates.

[0067] In addition, the compound (b-2) can be used in the production of printed matter having chemical resistance at a level that does not cause peeling of the coating film even when it comes into contact with chemicals such as alcohol, etc., and in order to obtain an active energy ray-curable ink having better adhesion to various substrates including plastic substrates, it is preferably used in combination with the compound (a2), (a3), the compound (b-1), etc.

[0068] As the compound (b-2), for example, 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 dicyclopentenyl oxyethyl (meth)acrylate can be used. Among them, using isobornyl (meth)acrylate is more preferable for obtaining an ink that can be used in the production of printed matter having a printed coating film with excellent chemical resistance.

[0069] The compound (b-2) is preferably used in the range of 5% by mass to 24% by mass based on the total amount of the polymerizable compound (A), and using it in the range of 5% by mass to 20% by mass is more preferable for obtaining an ink that can be used in the production of printed matter having a printed coating film with even better chemical resistance.

[0070] Especially, when using the compound (a1) as the polymerizable compound (A), using the compound (b-2) in combination is preferable for reducing the tackiness of the coating film, and the ratio of the structure represented by the general formula (1) possessed by the compound (a1) to the total of the aliphatic cyclic structures possessed by the compound (a2), the compound (a4), the compound (a5), and the compound (b-2) [the structure represented by the general formula (1) / the total of the aliphatic cyclic structures possessed by the compound (a2), the compound (a4), the compound (a5), and the compound (b-2)] is preferably used in combination in the range of 3 to 50.

[0071] As the active energy ray-curable ink of the present invention, those containing a photopolymerization initiator can be used in addition to the polymerizable compound (A).

[0072] 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-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyldimethyl 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, isophthalophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, etc. can be used.

[0073] Among the above, it is preferable to use an acylphosphine oxide-based photopolymerization initiator as the photopolymerization initiator.

[0074] In addition, when using a UV-LED light source as the light source of active energy rays 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, etc. corresponding to the wavelength of the light emitted from the UV-LED light source are preferably used.

[0075] In addition, it is preferable to use the photopolymerization initiator in combination with a sensitizer. As the sensitizer, for example, amines that do not react with the polymerizable compound (A) such as trimethylamine, methyldiethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, and 4,4'-bis(diethylamino)benzophenone can be used.

[0076] The active energy ray-curable ink of the present invention can use those containing a colorant as necessary in addition to the polymerizable compound (A) and the photopolymerization initiator.

[0077] As the colorant, for example, pigments and dyes can be used. As the pigment, for example, phthalocyanine pigments used in cyan ink, quinacridone-based pigments used in magenta ink, azo pigments used in yellow ink, carbon black used in black ink, white pigments that can be used in white ink, etc. can be mentioned.

[0078] Examples of the phthalocyanine pigment used in the cyan ink include C.I. Pigment Blue 1, 2, 3, 15:3, 15:4, 16:6, 16, 17:1, 75, 79, etc.

[0079] Examples of quinacridone pigments used in magenta ink include C.I. Pigment Red 122, C.I. Pigment Red 202, C.I. Pigment Red 209, C.I. Pigment Violet 19, etc.

[0080] Examples of azo pigments used in yellow ink include monoazo and disazo pigments such as C.I. Pigment Yellow 120, 151, 154, 175, 180, 181, 1, 65, 73, 74, 116, 12, 13, 17, 81, 83, 150, 155, 214, 128, etc.

[0081] Examples of carbon blacks used in black ink include No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. of Mitsubishi Chemical Corporation; Raven5750, 5250, 5000, 3500, 1255, 700, etc. of Columbian; Regal400R, 330R, 660R, Mogul L, 700, Monarch800, 880, 900, 1000, 1100, 1300, 1400, etc. of Cabot; Color Black FW1, FW2, FW2V, FW18, FW200, ColorBlack S150, S160, S170, Printex 35, U, V, 140U, Special Black 6, 5, 4A, 4, etc. of Degussa.

[0082] There is no particular limitation on the white pigment that can be used in white ink, and known inorganic white pigments can be used. Examples of the inorganic white pigments include sulfates or carbonates of alkaline earth metals, silicas such as fine silica and synthetic silicates, calcium silicate, alumina, alumina hydrate, titanium oxide, zinc oxide, talc, clay, etc. As the inorganic white pigments, those whose surfaces such as the above-mentioned silicas are surface-treated by various surface treatment methods can also be used.

[0083] The volume average particle diameter of the pigment preferably ranges from 10 to 300 nm, more preferably from 50 to 200 nm.

[0084] In order to obtain sufficient image density and light resistance 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 with respect to the total amount of each ink. Also, it is preferable to make the pigment concentration of the magenta ink higher than that of other color inks. Specifically, it is preferable that the pigment concentration is 1.2 times or more, more preferably 1.2 to 4 times, that of other color inks.

[0085] As the volume average particle diameter of the titanium oxide, those having a volume average particle diameter of 100 to 500 nm are preferably used, and in order to obtain an ink having more excellent ejection stability and high color developability of the printed image, those having a volume average particle diameter of 150 nm to 400 nm are more preferably used.

[0086] The pigment may be used in combination with a pigment dispersant, a pigment derivative (synergist), etc. for the purpose of enhancing the dispersion stability with respect to the polymerizable compound (A), etc.

[0087] As the pigment dispersant, for example, Ajisper PB821, PB822, PB817 manufactured by Ajinomoto Fine-Techno Co., Ltd., Solsperse 24000GR, 32000, 33000, 39000 manufactured by Avecia, and Disparon DA-703-50, DA-705, DA-725 manufactured by Nippon Kayaku Co., Ltd. can be used.

[0088] The amount of the pigment dispersant used is preferably in the range of 10 to 100% by mass with respect to the pigment, and in order to obtain an ink having more excellent ejection stability and pigment dispersibility, those in the range of 20 to 60% by mass are more preferably used. Also, as the pigment derivative, for example, a sulfonic acid derivative of the pigment can be used.

[0089] As the active energy ray-curable ink of the present invention, in addition to the above-described components, those containing a polymerization inhibitor such as hydroquinone, methoxyquinone, di-t-butylhydroquinone, p-methoxyphenol, butylhydroxytoluene, nitrosoamine salt, etc. can be used as needed. The polymerization inhibitor can be used in the range of 0.01% by mass to 2% by mass based on the total amount of the ink of the present invention.

[0090] As the active energy ray-curable ink of the present invention, for example, those containing a sensitizer such as trimethylamine, methyldiethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, and 4,4'-bis(diethylamino)benzophenone can be used.

[0091] As the active energy ray-curable ink of the present invention, in order to further improve the adhesion to a substrate such as a plastic substrate, those containing a non-reactive resin such as an acrylic resin, an epoxy resin, a terpene phenol resin, a rosin ester, etc. can be used.

[0092] As the active energy ray-curable ink of the present invention, it is preferably those having a viscosity at 25°C in the range of 3 mPa·sec to 30 mPa·sec, and more preferably those in the range of 5 mPa·sec to 20 mPa·sec in terms of the effect of inkjet ejection stability.

[0093] The active energy ray-curable ink of the present invention can be produced, for example, by dispersing a mixture of the polymerizable compound (A), a pigment, a pigment dispersant, and a resin as needed using an ordinary disperser such as a bead mill, adding a photoinitiator, and further adding additives such as a polymerization inhibitor, a sensitizer, and a surface tension modifier as needed, and stirring and dissolving them.

[0094] The active energy ray curable ink can also be produced by first manufacturing a high-concentration pigment dispersion (mill base) containing a pigment, a pigment dispersant, a resin, etc. using a conventional dispersing machine such as a bead mill, and then supplying a photoinitiator, a polymerizable compound (A), an additive, etc. and stirring and mixing them.

[0095] As the dispersing machine, in addition to a bead mill, for example, 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, a nanomizer, etc. can be used.

[0096] The active energy ray curable ink of the present invention cures by irradiating active energy rays, preferably light such as ultraviolet rays. As a light source such as ultraviolet rays, usually, a light source used for active energy ray curable inkjet recording inks, for example, a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a UV-LED lamp, etc. can be used.

[0097] The active energy ray curable ink of the present invention can be preferably used for printing by an inkjet recording method using only an inkjet recording apparatus.

[0098] As the inkjet recording method, any conventionally known method can be used. For example, 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 mechanical deformation of an electrostrictive element) and a method of utilizing thermal energy can be mentioned.

[0099] By ejecting the active energy ray curable ink onto a substrate as a recording medium using an inkjet recording apparatus and irradiating it with active energy rays to cure it, a printed matter can be produced. Examples of the printed matter include advertisements, signboards, guide plates, promotional product printing, etc.

[0100] The active energy ray curable ink of the present invention is excellent in adhesion to various base materials as the recording medium, and thus can be easily printed on the surface of a base material having a curved surface or an irregular shape with unevenness.

[0101] As the base material, for example, a plastic base material can be used. Specifically, as the plastic base material, ABS (acrylonitrile-butadiene-styrene) resin, PVC (polyvinyl chloride) / ABS resin, PA (polyamide) / ABS resin, PC (polycarbonate) / ABS resin, PBT (polybutylene terephthalate) / ABS and other ABS-based polymer alloys used as general-purpose injection molding plastics, AAS (acrylonitrile-acrylic rubber-styrene) resin, AS (acrylonitrile-styrene) resin, AES (acrylonitrile-ethylene rubber-styrene) resin, MS ((meth)acrylate-styrene) resin, PC (polycarbonate) resin, acrylic resin, methacrylic resin, PP (polypropylene) resin, and other base materials can be mentioned.

[0102] Also, as the plastic base material, for example, a thermoplastic resin film used for packaging materials can be used.

[0103] 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, polyethylene film (LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film), and polyolefin films such as polypropylene film (CPP: unoriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. As the thermoplastic resin film, those subjected to stretching treatments such as uniaxial stretching or biaxial stretching, or those subjected to surface treatments such as flame treatment or corona discharge treatment can also be used.

Example

[0104] Hereinafter, the present invention will be described in more detail with reference to examples.

[0105] [Preparation Example of Pigment Dispersion] Preparation Example of Cyan Pigment Dispersion (1) 10 parts by mass of Fastgen Blue TGR-G (phthalocyanine pigment C.I. Pigment Blue 15:4 manufactured by DIC Corporation), 4.5 parts by mass of Solsperse 32000 (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 with a stirrer for 1 hour, and then treated with a bead mill for 2 hours to obtain a cyan pigment dispersion (1).

[0106] [Example 1] According to the blending ratio described in Example 1 of Table 1, MIRAMER M3130 (ethylene oxide (EO) modified trimethylolpropane triacrylate manufactured by MIWON), MIRAMER M240 (ethylene oxide (EO) modified bisphenol A diacrylate manufactured by MIWON), MEDOL-10 (manufactured by Osaka Organic Chemical Industry Co., Ltd., (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate), 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.), KF-54 (polysiloxane manufactured by Shin-Etsu Chemical Co., Ltd.) were placed in a container and stirred and mixed, and then Irgacure819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF), Irgacure.TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide manufactured by BASF), Kayacure DETX-S (diethylthiobenzophenone manufactured by Nippon Kayaku Co., Ltd.) were added and dissolved by mixing at a temperature of 60°C for 30 minutes.

[0107] Next, the cyan pigment dispersion (1) was added and stirred and mixed for 10 minutes to obtain an active energy ray curable ink (C1) that can also be used for inkjet printing.

[0108] [Example 2] The amount of use of MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 20 parts by mass to 27 parts by mass, and the amount of use of POA (phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 16.3 parts by mass to 9.3 parts by mass. An active energy ray curable ink (C2) was obtained in the same manner as in Example 1 except for this.

[0109] [Example 3] The amount of use of MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 20 parts by mass to 34 parts by mass, and the amount of use of POA (phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 16.3 parts by mass to 2.3 parts by mass. An active energy ray curable ink (C3) was obtained in the same manner as in Example 1 except for this.

[0110] [Example 4] The amount of use of MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 20 parts by mass to 27 parts by mass, and the amount of use of V-CAP (N-vinyl-2-caprolactam manufactured by ISP) was changed from 12 parts by mass to 5 parts by mass. An active energy ray curable ink (C4) was obtained in the same manner as in Example 1 except for this.

[0111] [Example 5] The amount of MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 20 parts by mass to 27 parts by mass, the amount of POA (phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 16.3 parts by mass to 19.3 parts by mass, and the amount of IBXA (isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 15 parts by mass to 5 parts by mass. Otherwise, an active energy ray-curable ink (C5) was obtained in the same manner as in Example 1.

[0112] [Example 6] The amount of MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 20 parts by mass to 27 parts by mass, the amount of POA (phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 16.3 parts by mass to 3.3 parts by mass, and the amount of IBXA (isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 15 parts by mass to 21 parts by mass. Otherwise, an active energy ray-curable ink (C6) was obtained in the same manner as in Example 1.

[0113] [Comparative Example 1] The amount of MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, manufactured by Osaka Organic Chemical Industry) was changed from 20 parts by mass to 0 parts by mass, the amount of POA (phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 16.3 parts by mass to 9.3 parts by mass, and the amount of tetrahydrofurfuryl acrylate was changed from 0 parts by mass to 27 parts by mass. Otherwise, an active energy ray-curable ink (C’1) was obtained in the same manner as in Example 1.

[0114] [Comparative Example 2] The amount of POA (phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 9.3 parts by mass to 36.1 parts by mass, and the amount of tetrahydrofurfuryl acrylate was changed from 27 parts by mass to 0.2 parts by mass. Otherwise, an active energy ray-curable ink (C’2) was obtained in the same manner as in Comparative Example 1.

[0115] [Comparative Example 3] An active energy ray-curable ink (C'3) was obtained in the same manner as in Comparative Example 1, except that the amount of POA (phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 9.3 parts by mass to 36.3 parts by mass, and the amount of tetrahydrofurfuryl acrylate was changed from 27 parts by mass to 0 parts by mass. [Comparative Example 4] An active energy ray-curable ink (C'4) was obtained in the same manner as in Comparative Example 1, except that the amount of POA (phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd.) was changed from 9.3 parts by mass to 30.3 parts by mass, the amount of tetrahydrofurfuryl acrylate was changed from 27 parts by mass to 0 parts by mass, and the amount of IBXA (isobornyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.) was changed from 15 parts by mass to 21 parts by mass.

[0116] [Skin Irritation] Evaluation was made according to the degree of skin irritation caused by tetrahydrofurfuryl acrylate. Those considered to have high skin irritation caused by tetrahydrofurfuryl acrylate were evaluated as "×", those considered to have low skin irritation were evaluated as "△", and those considered to have no skin irritation caused by tetrahydrofurfuryl acrylate were evaluated as "○".

[0117] [Table 1]

[0118] [Table 2]

[0119] The abbreviations shown in Tables 1 and 2 refer to the following compounds. M3130: Ethylene oxide (EO) modified trimethylolpropane triacrylate manufactured by MIWON M240: Ethylene oxide (EO) modified bisphenol A diacrylate manufactured by MIWON MEDOL: (2-Methyl-2-ethyl-1,3-dioxolan-4-yl)methyl 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 POA: Phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd. THFA: Tetrahydrofurfuryl acrylate KF-54: Polysiloxane manufactured by Shin-Etsu Chemical Co., Ltd. Irgacure819: Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF IrgacureTPO: 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide manufactured by BASF ·Kayacure DETX-S: Diethylthioxanthone manufactured by Nippon Kayaku Co., Ltd. [Irgacure819 / IrgacureTPO]: Weight ratio of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide to 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

[0120] [Examples 7 to 12] According to the mixing ratios of the compositions described in Tables 3 and 4, an active energy ray-curable inkjet recording ink was manufactured. Specifically, in a container, 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.), MEDOL-10 ((2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.), V200 (viscoat #200, cyclic trimethylolpropane formal acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd.), FX-AO-MA (methyl 2-allyloxymethylacrylate manufactured by Nippon Shokubai 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 small amount of tetrahydrofurfuryl alcohol, and KF-54 (polysiloxane manufactured by Shin-Etsu Chemical Co., Ltd.) were put in and stirred and mixed. Then, Irgacure819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF), Irgacure.TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide manufactured by BASF), and Kayacure DETX-S (diethylthioxanthone manufactured by Nippon Kayaku Co., Ltd.) were added and dissolved by mixing at 60 °C for 30 minutes.

[0121] Next, the cyan pigment dispersion (1) was added and stirred and mixed for 10 minutes to obtain an active energy ray-curable ink (C7 - C12).

[0122] [Substrate adhesion] The active energy ray-curable ink was applied to a polycarbonate plate (Lexan, manufactured by Asahi Glass Co., Ltd., thickness 1 mm, PC) and a vinyl chloride sheet (vinyl chloride sheet manufactured by DIC Corporation, PVC) with a spin coater to a thickness of 10 μm, and then irradiated with an LED irradiation device (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2 ) manufactured by Hamamatsu Photonics K.K. equipped with a stage moving device until the tack on the surface of the coating film disappeared (became tack-free).

[0123] After making 25 cuts of 5×5 in the obtained cured coating film with a cutter knife, a cellophane tape manufactured by Nichiban Co., Ltd. was attached and rubbed about 10 times with a claw. The tape was vigorously peeled off at a peeling speed of about 1 cm / sec, and the number of squares of the coating film remaining on the surface of the polycarbonate plate or the vinyl chloride sheet was confirmed.

[0124] Evaluation Criteria ◎: The number of squares of the coating film remaining on the surface of the polycarbonate plate or the vinyl chloride sheet was 25, and no chipping of the coating film near the cuts occurred.

[0125] ○: The number of squares of the coating film remaining on the surface of the polycarbonate plate or the vinyl chloride sheet was 20 or more.

[0126] △: The number of squares of the coating film remaining on the surface of the polycarbonate plate or the vinyl chloride sheet was 15 or more and less than 20.

[0127] ×: The number of squares of the coating film remaining on the surface of the polycarbonate plate or the vinyl chloride sheet was less than 15.

[0128] [Solvent Resistance] The active energy ray-curable ink was applied to a polycarbonate plate (Lexan, manufactured by Asahi Glass Co., Ltd., thickness 1 mm, PC) with a spin coater to a thickness of 10 μm, and then irradiated with an LED irradiation device (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2) was used to irradiate until the tack on the coating film surface disappeared (became tack-free).

[0129] A cotton swab dipped in a mixture of ethanol and water (ethanol content: 70% by mass) was placed on the obtained cured coating film, and it was rubbed 10 times to the left and right with a width of about 2 cm. Those without rubbing marks on the coating film surface were evaluated as "○", and those with rubbing marks confirmed were evaluated as "×".

[0130] [Tackiness of coating film surface] The active energy ray curable ink was applied to a polycarbonate plate (Lexan, manufactured by Asahi Glass Co., Ltd., thickness 1 mm, PC) and a vinyl chloride sheet (vinyl chloride sheet manufactured by DIC Corporation, PVC) with a spin coater to a thickness of 10 μm, and then irradiated with an LED irradiation device (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2 ) was used to irradiate until the tack on the coating film surface disappeared (became tack-free).

[0131] Next, a stainless steel petri dish (Φ75 mm) was prepared, and a 15 g weight was attached to the inner side surface portion thereof.

[0132] Next, the stainless steel petri dish with the weight attached was fixed by hand in a state of standing on the coating film surface so that the positional relationship between the weight and the coating film surface was the positional relationship shown in Fig. 1.

[0133] Next, the hand was removed from the stainless steel petri dish, and it was evaluated based on the number of times the stainless steel petri dish swung left and right on the surface of the coating film and stopped. ○: 8 times or more ○-△: 6 - 7 times △: 5 - 6 times △-×: 3 - 4 times ×: 0 - 2 times

[0134]

Table 3

[0135]

Table 4

Explanation of Symbols

[0136] 1 Stainless steel petri dish 2 Weight 3 Coating film surface

Claims

1. A polymerizable compound (A) containing a compound (a2) having a structure represented by the following general formula (2), a compound (b) having a polymerizable unsaturated double bond other than the compound (a2), the compound (a3) represented by the following general formula (3), and the compound (a4) represented by the following general formula (4), wherein the compound (b) includes a compound (b-1) having a heterocyclic structure other than the following chemical formula (5) and a compound (b-2) having an aliphatic cyclic structure, the compound (a2) is contained in an amount of 5% by mass to 38% by mass based on the total amount of the polymerizable compound (A), the compound (b-1) is N-vinyl-2-caprolactam and is contained in an amount of 1% by mass to 15% by mass based on the total amount of the polymerizable compound (A), the compound (b-2) is isobornyl (meth)acrylate and is contained in an amount of 5% by mass to 24% by mass based on the total amount of the polymerizable compound (A), An active energy ray-curable ink characterized by not containing a compound having a structure represented by the following chemical formula (5). (R in the general formula (2) １ and R ２ each independently represent a hydrogen atom or an alkyl group, and R ３ represents a hydrogen atom or an alkyl group.) (In general formula (3), R3 represents a hydrogen atom or an alkyl group.) (In general formula (4), R1, R2, and R3 each independently represent a hydrogen atom or an alkyl group, and X1 represents a single bond or an alkylene group.)

2. The active energy ray-curable ink according to claim 1, wherein the polymerizable compound (A) further contains a compound (a1) having a structure represented by the following general formula (1) and a polymerizable unsaturated double bond. 〔In general formula (1), R １ is an alkylene group having 1 or more carbon atoms, and R ２ is an alkylene group having 1 or more carbon atoms which may be the same as or different from R １ , R ３ is a hydrogen atom or an alkyl group, and n is an integer of 0 or more.〕

3. The active energy ray-curable ink according to claim 2, wherein the polymerizable compound (A) contains the compound (a1) in the range of 20% by mass to 40% 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, having a viscosity at 25 °C in the range of 5 to 30 mPa·sec.

5. The active energy ray-curable ink according to any one of claims 1 to 4, further containing an acylphosphine oxide-based photoinitiator.

6. A method for producing a printed matter, characterized by discharging the active energy ray-curable ink according to any one of claims 1 to 5 onto a recording medium using an inkjet recording apparatus and irradiating the active energy ray to cure it.

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