Polymer-containing aqueous dispersions and aqueous inks

Abstract

To provide an emulsion particle-containing aqueous dispersion that has high adhesion to a substrate, particularly to olefinic substrates such as biaxially oriented polypropylene (OPP), an also has excellent scratch resistance, and a water-based ink.SOLUTION: An aqueous dispersion contains a polymer (A) having a structural unit derived from a cyclic aliphatic group-containing monomer and a wax component (B).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous dispersion containing a polymer. It also relates to an aqueous ink containing the aqueous dispersion containing the polymer. The aqueous ink of the present invention can be suitably used as an ink such as an aqueous ink for inkjet, an ink for flexographic printing, an ink for offset printing, an ink for lithographic printing, an ink for gravure printing, an ink for screen printing, etc. The aqueous ink of the present invention can be particularly suitably used as an aqueous ink for inkjet.

Background Art

[0002] Inks are roughly classified into two types: organic solvent-based inks in which an organic solvent is used as the main component of the solvent, and aqueous inks in which water is used as the main component of the solvent.

[0003] Since the main component of the solvent in the organic solvent-based ink composition is an organic solvent, it has good water resistance. However, the organic solvent-based ink composition is inferior in safety to the human body and generates an odor based on the organic solvent. Therefore, in recent years, aqueous inks have been attracting attention.

[0004] For example, Patent Document 1 describes an inkjet ink composition containing a pigment, a polymer pigment dispersant, polymer particles, a hydrophilic organic solvent, water, at least one of a water-soluble acidic compound having a content of 50 to 1000 ppm and a molecular weight of 200 or less and a salt of the water-soluble acidic compound.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, there has been a growing demand for inkjet recording methods on resin recording media such as PET (polyethylene terephthalate), PP (polypropylene), and PVC (polyvinyl chloride), which have traditionally been printed using solvent-based inks or UV-curing inks. However, it has become clear that the water-based inks described in Patent Document 1 have insufficient adhesion and scratch resistance to resin recording media.

[0007] The object of the present invention is to provide an aqueous dispersion containing emulsion particles and an aqueous ink that exhibits excellent adhesion to a substrate, particularly to olefin-based substrates such as biaxially oriented polypropylene (OPP), even without the use of primers, and also has good scratch resistance. [Means for solving the problem]

[0008] In view of the above-mentioned problems, the inventors conducted research and found that an aqueous dispersion containing a polymer (A) having structural units derived from a cyclic aliphatic group-containing monomer and a wax component (B) exhibits excellent adhesion to substrates when used as an aqueous ink, particularly to olefin-based substrates such as biaxially oriented polypropylene (OPP), and also has good scratch resistance, thus completing the present invention. [Effects of the Invention]

[0009] According to the present invention, a polymer-containing aqueous dispersion and an aqueous ink are provided that exhibit excellent adhesion to a substrate, particularly to olefin-based substrates such as biaxially oriented polypropylene (OPP), even without the use of a primer, and also have good scratch resistance. [Modes for carrying out the invention]

[0010] The polymer-containing aqueous dispersion of the present invention is characterized by being an aqueous dispersion containing a polymer (A) having structural units derived from a cyclic aliphatic group-containing monomer and a wax component (B).

[0011] Because the aqueous dispersion is used in the aqueous ink of the present invention, it exhibits excellent adhesion to the substrate, particularly to olefin-based substrates such as biaxially oriented polypropylene (OPP), even without a primer, and also has excellent scratch resistance.

[0012] <Polymer (A)> The polymer (A) of this disclosure is preferably a polymer having structural units derived from cyclic aliphatic group-containing monomers. Having structural units derived from cyclic aliphatic group-containing monomers allows for excellent adhesion to substrates, particularly to olefin-based substrates such as biaxially oriented polypropylene (OPP), and it is expected that a polymer with good adhesion can be obtained even without primers.

[0013] The structural units derived from the cyclic aliphatic group-containing monomers of this disclosure only need to have the same structure as the structure in which at least one carbon-carbon double bond of the cyclic aliphatic group-containing monomer is replaced by a carbon-carbon single bond. They are not limited to structural units formed by polymerization of the cyclic aliphatic group-containing monomers, but may also be structural units formed by, for example, post-reactions after polymerization.

[0014] As structural units derived from cyclic aliphatic group-containing monomers, those represented by the following formula (1) are preferred. In the following formula (1), R 1 R represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms. 2 This represents a cyclic aliphatic group.

[0015] [ka]

[0016] Examples of cyclic aliphatic groups in formula (1) include cyclopentyl group, adamantyl group, isobornyl group, dicyclopentanyl group, and dicyclopentenyl group, with cyclopentyl group, cyclohexyl group, and isobornyl group being preferred, and cyclohexyl group and isobornyl group being more preferred.

[0017] The cyclic aliphatic group-containing monomers of this disclosure are preferably monomers having a carbon-carbon double bond, and include (meth)acrylate monomers having a cyclic aliphatic hydrocarbon group.

[0018] The (meth)acrylate monomer having a cyclic aliphatic hydrocarbon group is preferably a compound having a monovalent cyclic aliphatic hydrocarbon group and a monovalent (meth)acrylate group, where the monovalent cyclic aliphatic hydrocarbon group and the monovalent (meth)acrylate group are directly bonded. Examples of cyclic aliphatic hydrocarbon groups include monocyclic groups, polycyclic groups, and cross-linked ring groups. The number of carbon atoms in the cyclic aliphatic hydrocarbon group is preferably 4 to 20. The cyclic aliphatic hydrocarbon group is preferably a cyclic aliphatic group having 4 to 20 carbon atoms, particularly 5 to 12 carbon atoms. The number of carbon atoms in the cyclic aliphatic hydrocarbon group is preferably 15 or less, for example, 10 or less. It is preferable that the carbon atoms in the ring of the cyclic aliphatic hydrocarbon group are directly bonded to the ester group in the (meth)acrylate group. Specific examples of cyclic aliphatic hydrocarbon groups are cyclohexyl group, t-butylcyclohexyl group, isobornyl group, dicyclopentanyl group, and dicyclopentenyl group. The (meth)acrylate group is either an acrylate group or a methacrylate group, but a methacrylate group is preferred.

[0019] Specific examples of monomers having a cyclic aliphatic hydrocarbon group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyl (meth)acrylate. Cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate are preferred, and cyclohexyl (meth)acrylate and isobornyl (meth)acrylate are more preferred.

[0020] These cyclic aliphatic group-containing monomers can be used alone or in combination of several types.

[0021] From the viewpoint of adhesion, the content of the structural unit derived from the monomer having a cyclic aliphatic hydrocarbon group in 100 parts by mass of the polymer (A) of the present disclosure may be 30 parts by mass or more, preferably 35 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 45 parts by mass or more, and may be 95 parts by mass or less, preferably 90 parts by mass or less, and more preferably 85 parts by mass or less.

[0022] The polymer (A) of the present disclosure may have a structural unit derived from other monomers in addition to the structural unit derived from the cyclic aliphatic group-containing monomer.

[0023] The structural unit derived from other monomers is not limited to the structural unit formed by polymerizing other monomers described below, and may be, for example, a structural unit formed by a post-reaction after polymerization.

[0024] Examples of other monomers include monofunctional monomers and polyfunctional monomers. The monofunctional monomers and polyfunctional monomers may be used alone or in combination.

[0025] Examples of monofunctional monomers include (meth)acrylic acid esters having a linear alkyl group, (meth)acrylic acid esters having a branched alkyl group, acid group-containing monomers, hydroxyl group-containing (meth)acrylates, oxo group-containing monomers, fluorine atom-containing monomers, nitrogen atom-containing monomers, epoxy group-containing monomers, alkoxyalkyl (meth)acrylates, silane group-containing monomers, carbonyl group-containing monomers, aziridinyl group-containing monomers, styrene-based monomers, aralkyl (meth)acrylates, addition-polymerizable oxazolines, etc., but are not limited to such examples.

[0026] The linear alkyl group-containing (meth)acrylic acid esters of this disclosure include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, aminoethyl (meth)acrylate, chloroethyl (meth)acrylate, trifluoroethyl (meth)acrylate, and (meth) Examples include heptadecafluorooctylethyl acrylate, and from the viewpoint of adhesion and scratch resistance, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate are preferred, and methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate are more preferred.

[0027] Examples of (meth)acrylic acid esters having a branched alkyl group in this disclosure include isopropyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, methoxytripropylene glycol (meth)acrylate, and hexafluoropropyl (meth)acrylate. From the viewpoint of adhesion and scratch resistance, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, and isostearyl (meth)acrylate are preferred, and isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isostearyl (meth)acrylate are more preferred.

[0028] Examples of acid group-containing monomers of this disclosure include (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, monomethyl maleic acid, monobutyl maleic acid, monomethyl itaconic acid, monobutyl itaconic acid, vinylbenzoic acid, and other carboxyl group-containing aliphatic monomers. However, the present invention is not limited to these examples. These acid group-containing monomers may be used individually or in combination of two or more types. Among these acid group-containing monomers, acrylic acid, methacrylic acid, and itaconic acid are preferred, and acrylic acid and methacrylic acid are more preferred, from the viewpoint of improving the dispersion stability, adhesion, and scratch resistance of the aqueous dispersion when polymer (A) is emulsion particles.

[0029] Examples of hydroxyl group-containing (meth)acrylates in this disclosure include, but are not limited to, hydroxyl group-containing (meth)acrylates with ester groups having 1 to 18 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among these hydroxyl group-containing monomers, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred from the viewpoint of improving adhesion and scratch resistance.

[0030] These hydroxyl group-containing (meth)acrylates may be used individually or in combination of two or more types.

[0031] Examples of oxo group-containing monomers in this disclosure include, but are not limited to, (di)ethylene glycol (methoxy)(meth)acrylates such as ethylene glycol (meth)acrylate, ethylene glycol methoxy(meth)acrylate, diethylene glycol (meth)acrylate, and diethylene glycol methoxy(meth)acrylate. These oxo group-containing monomers may be used individually or in combination of two or more types.

[0032] Examples of fluorine atom-containing monomers in this disclosure include, but are not limited to, fluorine atom-containing alkyl (meth)acrylates with 2 to 6 carbon atoms in the ester group, such as trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, and octafluoropentyl (meth)acrylate. These fluorine atom-containing monomers may be used individually or in combination of two or more types.

[0033] Examples of nitrogen atom-containing monomers in this disclosure include, but are not limited to, acrylamide compounds such as (meth)acrylamide, N-monomethyl(meth)acrylamide, N-monoethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, Nn-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, methylenebis(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, dimethylaminoethyl(meth)acrylamide, N,N-dimethylaminopropylacrylamide, and diacetoneacrylamide; nitrogen atom-containing (meth)acrylate compounds such as dimethylaminoethyl(meth)acrylate and diethylaminoethyl(meth)acrylate; N-vinylpyrrolidone; and (meth)acrylonitrile. These nitrogen atom-containing monomers may be used individually or in combination of two or more types.

[0034] Examples of epoxy group-containing monomers in this disclosure include, but are not limited to, epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, and glycidyl allyl ether. These epoxy group-containing monomers may be used individually or in combination of two or more types. Among these epoxy group-containing monomers, glycidyl (meth)acrylate is preferred from the viewpoint of improving adhesion and scratch resistance.

[0035] Examples of the alkoxyalkyl (meth)acrylates of this disclosure include, but are not limited to, methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, and trimethylolpropane tripoxy (meth)acrylate. These alkoxyalkyl (meth)acrylates may be used individually or in combination of two or more types.

[0036] Examples of silane group-containing monomers of this disclosure include, but are not limited to, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, vinyltrichlorosilane, γ-(meth)acryloyloxypropylhydroxysilane, and γ-(meth)acryloyloxypropylmethylhydroxysilane. These silane group-containing monomers may be used individually or in combination of two or more types.

[0037] Examples of carbonyl group-containing monomers in this disclosure include, but are not limited to, acrolein, homyl styrene, vinyl ethyl ketone, (meth)acryloxyalkyl propenal, acetonyl (meth)acrylate, diacetone (meth)acrylate, 2-hydroxypropyl (meth)acrylate acetyl acetate, butanediol-1,4-acrylate acetyl acetate, and 2-(acetoacetoxy)ethyl (meth)acrylate. These carbonyl group-containing monomers may be used individually or in combination of two or more types.

[0038] Examples of the aziridinyl group-containing monomers of this disclosure include (meth)acryloylaziridine and 2-aziridinylethyl (meth)acrylate, but are not limited to these examples. These aziridinyl group-containing monomers may be used individually or in combination of two or more types.

[0039] Examples of styrene monomers in this disclosure include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, and vinyltoluene. These styrene monomers may be used individually or in combination of two or more types. The styrene monomers may have functional groups on the benzene ring, such as methyl groups, alkyl groups such as tert-butyl groups, nitro groups, nitrile groups, alkoxyl groups, acyl groups, sulfone groups, hydroxyl groups, and halogen atoms. Among the styrene monomers, styrene is preferred from the viewpoint of improving water resistance.

[0040] Examples of aralkyl (meth)acrylates in this disclosure include, but are not limited to, aralkyl (meth)acrylates having an aralkyl group with 7 to 18 carbon atoms, such as benzyl (meth)acrylate, phenylethyl (meth)acrylate, methylbenzyl (meth)acrylate, and naphthylmethyl (meth)acrylate. These aralkyl (meth)acrylates may be used individually or in combination of two or more types.

[0041] Examples of addition-polymerizable oxazolines in this disclosure include, but are not limited to, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These addition-polymerizable oxazolines may be used individually or in combination of two or more. Among these addition-polymerizable oxazolines, 2-isopropenyl-2-oxazoline is preferred due to its readily available availability.

[0042] Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethylene oxide-modified 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate. Di(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms; alkyl di(meth)acrylates with 2 to 50 added moles of alkylene oxide groups with 2 to 4 carbon atoms, such as polyethylene glycol di(meth)acrylate with 2 to 50 added moles of ethylene oxide, polypropylene glycol di(meth)acrylate with 2 to 50 added moles of propylene oxide, and tripropylene glycol di(meth)acrylate; ethoxylated glycerin tri(meth)acrylate, propylene oxide modified glycerol tri(meth)acrylate, Tri(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms, such as ethylene oxide-modified trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol monohydroxytri(meth)acrylate, and trimethylolpropane triethoxytri(meth)acrylate; and tetra(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms, such as pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. La(meth)acrylate; penta(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms, such as pentaerythritol penta(meth)acrylate and dipentaerythritol (monohydroxy)penta(meth)acrylate; hexa(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms, such as pentaerythritol hexa(meth)acrylate; epoxy group-containing (meth)acrylates, such as bisphenol A di(meth)acrylate, 2-(2'-vinyloxyethoxyethyl)(meth)acrylate, and epoxy(meth)acrylate;Examples include, but are not limited to, polyfunctional (meth)acrylates such as urethane (meth)acrylates. These polyfunctional monomers may be used individually or in combination of two or more types.

[0043] From the viewpoint of imparting UV stability or UV absorption, it is preferable that the polymer (A) of this disclosure contains UV-stable monomers, UV-absorbing monomers, etc., as monomer components, within a range that does not hinder the objectives of the present invention.

[0044] Examples of UV-stable monomers in this disclosure include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, and 4-crotonoylamino- Examples of piperidine group-containing monomers include 2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, but the present invention is not limited to these examples. These monomers may be used individually or in combination of two or more types. Among these UV-stable monomers, piperidyl group-containing (meth)acrylates such as 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, and 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine are preferred from the viewpoint of improving adhesion and scratch resistance.

[0045] Examples of UV-absorbing monomers in this disclosure include benzotriazole-based UV-absorbing monomers and benzophenone-based UV-absorbing monomers, but the present invention is not limited to these examples. These monomers may be used individually or in combination of two or more types.

[0046] Examples of benzotriazole-based UV-absorbing monomers include 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxymethylphenyl]-5-tert-butyl-2H-benzotriazole, and 2-[2'-hydroxy-5'-(meth )acryloylaminomethyl-5'-tert-octylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxypropylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyhexylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole , 2-[2'-hydroxy-3'-tert-butyl-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-tert-butyl-3'-(meth)acryloyloxyethylphenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)ac Examples include liloyloxyethylphenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-tert-butyl-2H-benzotriazole, and 2-[2'-hydroxy-5'-(β-(meth)acryloyloxyethoxy)-3'-tert-butylphenyl]-4-tert-butyl-2H-benzotriazole, but the present invention is not limited to these examples. These monomers may be used individually or in combination of two or more.

[0047] Examples of benzophenone-based UV-absorbing monomers include 2-hydroxy-4-(meth)acryloyloxybenzophenone, 2-hydroxy-4-[2-hydroxy-3-(meth)acryloyloxy]propoxybenzophenone, 2-hydroxy-4-[2-(meth)acryloyloxy]ethoxybenzophenone, 2-hydroxy-4-[3-(meth)acryloyloxy-2-hydroxypropoxy]benzophenone, and 2-hydroxy-3-tert-butyl-4-[2-(meth)acryloyloxy]butoxybenzophenone, but the present invention is not limited to these examples. These monomers may be used individually or in combination of two or more types.

[0048] As other monomers in this disclosure, from the viewpoint of further improving adhesion to corona-treated PET, OPP, etc., piperidine group-containing monomers, nitrogen atom-containing monomers, and addition-polymerizable oxazolines are preferred, among which piperidine group-containing monomers and addition-polymerizable oxazolines are more preferred, and 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, and 2-isopropenyl-2-oxazoline are even more preferred. Furthermore, if a hydroxyl group-containing (meth)acrylate is included as a monofunctional monomer, emulsion particles without coarse particles are easily obtained, the discharge stability of the ink containing the emulsion particles is excellent, and from the viewpoint of further improving adhesion, it is preferable to include a hydroxyl group-containing (meth)acrylate.

[0049] The content of structural units derived from other monomers in 100 parts by mass of polymer (A) of the present disclosure may be 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, may be 70 parts by mass or less, preferably 65 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less.

[0050] The acid value of polymer (A) in this disclosure does not have to have an acid value, but may be 50 mg KOH / g or less, preferably 40 mg KOH / g or less, more preferably 35 mg KOH / g or less, and even more preferably 30 mg KOH / g or less. By having the acid value of polymer (A) within the above range, a suitable viscosity aqueous ink for inkjet applications can be obtained, and an effect of improving scratch resistance can be expected.

[0051] Furthermore, the acid value of polymer (A) of this disclosure may be 1 mg KOH / g or higher from the viewpoint of suppressing aggregation and suppressing viscosity changes when used as an ink.

[0052] The glass transition temperature of polymer (A) of the present disclosure may be -10°C or higher, preferably 0°C or higher, more preferably 5°C or higher, even more preferably 10°C or higher, may be 90°C or lower, preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 60°C or lower.

[0053] The glass transition temperature (Tg) of a polymer is calculated using the glass transition temperature of the homopolymer of the monomer components used as raw materials for the polymer, using the formula: 1 / Tg = Σ(Wm / Tgm) / 100 This refers to the temperature determined based on Fox's formula, which is expressed as follows: [In the formula, Wm represents the content (mass%) of monomer m in the inner layer monomer component constituting the resin layer, and Tgm represents the glass transition temperature (absolute temperature: K) of the homopolymer of monomer m].

[0054] In this specification, unless otherwise specified, the glass transition temperature of a polymer refers to the glass transition temperature determined based on Fox's formula.

[0055] The polymer (A) of the present disclosure may be emulsion particles. The emulsion particles of the present disclosure may be single-layered or have a multilayer structure. If the emulsion particles of the present disclosure have a multilayer structure, it is preferable that there are two to four layers, and more preferably two or three layers. In emulsion particles having a multilayer resin layer, the inner layer means the innermost layer of the emulsion particle, the outer layer means the other layers excluding the innermost layer, and the outermost layer means the outermost layer formed.

[0056] When the polymer (A) of this disclosure is an emulsion particle, the volume-average particle diameter (nm) is preferably 25 nm to 500 nm, more preferably 50 nm to 400 nm, and most preferably 100 nm to 300 nm, from the viewpoint of blocking resistance, adhesion to the substrate, scratch resistance, discharge stability, and image quality improvement. The volume-average particle size of polymer (A) is not particularly limited, but can be measured by dynamic light scattering, laser diffraction / scattering, Coulter counter, microscopy, etc. The average particle diameter in this disclosure is the average particle diameter (hydrodynamic diameter) obtained by cumulant analysis using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], which is a particle diameter measurement device using dynamic light scattering, and by determining the autocorrelation function using the photon correlation method.

[0057] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the content of structural units derived from monomers having cyclic aliphatic hydrocarbon groups in 100 parts by mass of monomer components forming the inner layer may be 30 parts by mass or more, preferably 35 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 45 parts by mass or more, and may be 95 parts by mass or less, preferably 90 parts by mass or less, and more preferably 85 parts by mass or less.

[0058] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the content of structural units derived from other monomers in 100 parts by mass of monomer components forming the inner layer may be 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, may be 70 parts by mass or less, preferably 65 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less.

[0059] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, in 100 parts by mass of monomer components forming the inner layer, the other monomer-derived structural units are more preferably 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid, 2-ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, (meth)acrylonitrile, glycidyl (meth)acrylate, styrene, 2-isopropenyl-2-oxazoline, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, and 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine.

[0060] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the content of structural units derived from monomers having cyclic aliphatic hydrocarbon groups in 100 parts by mass of monomer components forming the outer layer may be 30 parts by mass or more, preferably 35 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 45 parts by mass or more, and may be 95 parts by mass or less, preferably 90 parts by mass or less, and more preferably 85 parts by mass or less.

[0061] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the content of other monomer-derived structural units in 100 parts by mass of monomer components forming the outer layer may be 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, may be 70 parts by mass or less, preferably 65 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less.

[0062] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, in 100 parts by mass of monomer components forming the outer layer, the other monomer-derived structural units are more preferably 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid, 2-ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, (meth)acrylonitrile, glycidyl (meth)acrylate, styrene, 2-isopropenyl-2-oxazoline, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, and 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine.

[0063] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the content of structural units derived from monomers having cyclic aliphatic hydrocarbon groups in 100 parts by mass of monomer components forming the outermost layer may be 30 parts by mass or more, preferably 35 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 45 parts by mass or more, and may be 95 parts by mass or less, preferably 90 parts by mass or less, and more preferably 85 parts by mass or less.

[0064] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the content of structural units derived from other monomers in 100 parts by mass of monomer components forming the outermost layer may be 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, may be 70 parts by mass or less, preferably 65 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less.

[0065] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, in 100 parts by mass of monomer components forming the outermost layer, the other monomer-derived structural units are more preferably 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid, 2-ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, (meth)acrylonitrile, glycidyl (meth)acrylate, styrene, 2-isopropenyl-2-oxazoline, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, and 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine.

[0066] The mass ratio of the polymer layer constituting the inner layer to the polymer layer constituting the outer layer of the present disclosure (mass of polymer constituting the inner layer / mass of polymer constituting the outer layer) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, even more preferably 30 / 70 to 70 / 30, and even more preferably 40 / 60 to 60 / 40, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance.

[0067] The mass ratio of the polymer layer constituting the inner layer to the polymer layer constituting the outermost layer (polymer layer constituting the inner layer / polymer layer constituting the outermost layer) of the present disclosure is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, even more preferably 30 / 70 to 70 / 30, and even more preferably 40 / 60 to 60 / 40, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance.

[0068] The acid value of the polymer constituting the inner layer of the present disclosure does not have to have an acid value, but it may be 50 mg KOH / g or less, preferably 40 mg KOH / g or less, more preferably 35 mg KOH / g or less, and even more preferably 30 mg KOH / g or less. By having the acid value of the inner layer of polymer (A) within the above range, a water-based ink with a suitable viscosity for inkjet use can be obtained, and improvements in adhesion, scratch resistance, and ejection stability can be expected. Furthermore, the acid value of the polymer constituting the inner layer of the present disclosure may be 1 mg KOH / g or more from the viewpoint of suppressing aggregation and suppressing viscosity changes when used as an ink.

[0069] The acid value of the polymer constituting the outer layer of this disclosure does not have to have an acid value, but it may be 50 mg KOH / g or less, preferably 40 mg KOH / g or less, more preferably 35 mg KOH / g or less, and even more preferably 30 mg KOH / g or less. By having the acid value of the outer layer of polymer (A) within the above range, a suitable viscosity aqueous ink for inkjet applications can be obtained, and improvements in adhesion, scratch resistance, and ejection stability can be expected. Furthermore, the acid value of the polymer constituting the outer layer of this disclosure may be 1 mg KOH / g or more from the viewpoint of suppressing aggregation and suppressing viscosity changes when used as an ink.

[0070] The acid value of the polymer constituting the outermost layer of this disclosure does not have to have an acid value, but it may be 50 mg KOH / g or less, preferably 40 mg KOH / g or less, more preferably 35 mg KOH / g or less, and even more preferably 30 mg KOH / g or less. By having the acid value of the outermost layer of polymer (A) within the above range, a suitable viscosity aqueous ink for inkjet applications can be obtained, and improvements in adhesion, scratch resistance, and ejection stability can be expected. Furthermore, the acid value of the polymer constituting the outermost layer of this disclosure may be 1 mg KOH / g or more from the viewpoint of suppressing aggregation and suppressing viscosity changes when used as an ink.

[0071] The glass transition temperature of the polymer constituting the inner layer of this disclosure is -10°C or higher, preferably 0°C or higher, from the viewpoint of adhesion and scratch resistance, and the upper limit of the glass transition temperature is preferably 120°C or lower, more preferably 100°C or lower, from the viewpoint of adhesion and scratch resistance. The glass transition temperature of the polymer forming the inner layer can be adjusted by adjusting the type and amount of monomers forming the inner layer.

[0072] The glass transition temperature of the polymer constituting the outer layer of this disclosure is 0°C or higher, preferably 10°C or higher, from the viewpoint of adhesion, scratch resistance, and film-forming properties. The upper limit of the glass transition temperature is preferably 100°C or lower, more preferably 90°C or lower, from the viewpoint of adhesion and scratch resistance. The glass transition temperature of the polymer forming the outer layer can be adjusted by adjusting the type and amount of monomers forming the outer layer.

[0073] The glass transition temperature of the polymer constituting the outermost layer of this disclosure is 0°C or higher, preferably 10°C or higher, from the viewpoint of adhesion, scratch resistance, and film-forming properties. The upper limit of the glass transition temperature is preferably 100°C or lower, more preferably 90°C or lower, from the viewpoint of adhesion and scratch resistance. The glass transition temperature of the polymer forming the outermost layer can be adjusted by adjusting the type and amount of monomers forming the outermost layer.

[0074] Unless otherwise specified, the glass transition temperatures of the polymers constituting each of the above layers refer to the glass transition temperatures determined based on Fox's equation, similar to the glass transition temperature of polymer (A).

[0075] <Method for producing polymer (A)> The polymer (A) of this disclosure can be obtained by polymerizing a monomer containing a cyclic aliphatic group monomer. Examples of polymerization methods include emulsion polymerization, bulk polymerization, solution polymerization, and suspension polymerization, but the present invention is not limited to these examples. Among the methods for polymerizing the monomer component, emulsion polymerization is preferred because an environmentally friendly aqueous dispersion can be directly obtained when the monomer component is polymerized by emulsion polymerization.

[0076] Methods for emulsion polymerization of monomer components include, but are not limited to, methods in which an emulsifier is dissolved in an aqueous medium containing a water-soluble organic solvent such as methanol or other lower alcohol and water, or in which monomer components and polymerization initiators are added dropwise under stirring, or in which monomer components that have been pre-emulsified with an emulsifier and water are added dropwise to water or an aqueous medium. The amount of medium should be set appropriately considering the amount of non-volatile content contained in the resulting emulsion. The medium may be charged into the reaction vessel in advance, or it may be used as a pre-emulsion. Furthermore, the medium may be used when emulsion polymerization of monomer components is being carried out to produce the emulsion, if necessary.

[0077] When emulsion polymerization of monomer components, emulsion polymerization may be carried out after mixing the monomer components, emulsifier and medium, or emulsion polymerization may be carried out after preparing a preemulsion by emulsifying the monomer components, emulsifier and medium by stirring, or emulsion polymerization may be carried out after mixing at least one of the monomer components, emulsifier and medium with the remainder of the preemulsion. The monomer components, emulsifier and medium may be added all at once, in installments, or continuously dropwise.

[0078] The monomers and monomer compositions used when polymerizing polymer (A) of the present disclosure are as described above. The monomers and monomer compositions used when polymer (A) of the present disclosure is an emulsion particle having a multilayer structure are as described above.

[0079] When the polymer (A) of this disclosure is an emulsion particle having a multilayer structure, an outer layer consisting of an outer polymer component can be formed on the emulsion particles contained in the emulsion obtained above by emulsion polymerization of monomer components in the emulsion in the same manner as above. Furthermore, when forming an outer layer on emulsion particles on which the outer layer (intermediate layer) has been formed, an outer layer consisting of another outer polymer component can be formed on the emulsion particles by emulsion polymerization of monomer components in the emulsion in the same manner as above. In this way, emulsion particles having a multilayer structure (core-shell emulsion particles) can be prepared by a multi-stage emulsion polymerization method.

[0080] Furthermore, when preparing core-shell emulsion particles, one or more stages of emulsion polymerization may be performed before the emulsion polymerization that forms the inner layer consisting of the polymer components for the inner layer, and one or more stages of emulsion polymerization may be performed between the emulsion polymerization that forms the inner layer and the emulsion polymerization that forms the intermediate layer. Also, one or more stages of emulsion polymerization may be performed between the emulsion polymerization that forms the intermediate layer and the emulsion polymerization that forms the outer layer. Moreover, one or more stages of emulsion polymerization may be performed after the emulsion polymerization that forms the outer layer.

[0081] Examples of emulsifiers used in the polymerization of polymer (A) of this disclosure include anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, and polymer emulsifiers. These emulsifiers may be used individually or in combination of two or more types.

[0082] Examples of anionic emulsifiers include alkyl sulfate salts such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonate salts such as ammonium dodecyl sulfonate, sodium dodecyl sulfonate, and sodium alkyldiphenyl ether disulfonate; alkylaryl sulfonate salts such as ammonium dodecylbenzene sulfonate and sodium dodecylnaphthalene sulfonate; polyoxyethylene alkyl sulfonate salts; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkylaryl sulfate salts; dialkyl sulfosuccinates; and aryl sulfonic acid-formaldehyde condensates. Examples include fatty acid salts such as ammonium laurylate and sodium stearate; sulfate esters or salts thereof having an allyl group, such as bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salt, propenyl-alkyl sulfosuccinate salt, (meth)acrylate polyoxyethylene sulfonate salt, (meth)acrylate polyoxyethylene phosphate salt, and sulfonate salt of allyloxymethylalkyloxypolyoxyethylene; sulfate ester salts of allyloxymethyl alkoxyethyl polyoxyethylene, polyoxyalkylene alkenyl ether sulfate ammonium salt, etc., but are not limited to these examples.

[0083] Examples of nonionic emulsifiers include, but are not limited to, polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, condensates of polyethylene glycol and polypropylene glycol, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid monoglycerides, condensation products of ethylene oxide and aliphatic amines, allyloxymethyl alkoxyethyl hydroxypolyoxyethylene, and polyoxyalkylene alkenyl ethers.

[0084] Examples of cationic emulsifiers include alkylammonium salts such as dodecylammonium chloride, but are not limited to these examples.

[0085] Examples of amphoteric emulsifiers include betaine ester type emulsifiers, but the examples are not limited to these.

[0086] Examples of polymer emulsifiers include, but are not limited to, poly(meth)acrylates such as sodium polyacrylate and ammonium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl (meth)acrylates such as polyhydroxyethyl acrylate; and copolymers in which one or more monomers constituting these polymers are copolymerized components.

[0087] Furthermore, as the emulsifier, from the viewpoint of further improving water resistance and image uniformity, an emulsifier having polymerizable groups, i.e., a so-called reactive emulsifier, is preferred, and from the viewpoint of environmental protection, a non-nonylphenyl type emulsifier is preferred.

[0088] Examples of reactive emulsifiers include propenyl-alkyl sulfosuccinate salts, (meth)acrylate polyoxyethylene sulfonate salts, (meth)acrylate polyoxyethylene phosphate salts [e.g., Sanyo Chemical Industries, Ltd., product name: Eleminol RS-30, etc.], polyoxyethylene alkylpropenylphenyl ether sulfonate salts [e.g., Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-10, etc.], allyloxymethylalkyloxypolyoxyethylene sulfonate salts [e.g., Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon KH-10, etc.], allyloxymethylnonylphenoxyethyl hydroxypolyoxyethylene sulfonate salts [e.g., ADEKA Corporation, product name: Adekarya Soap SE-10, etc.], allyloxymethyl alkoxyethyl hydroxypolyoxy Examples include, but are not limited to, these examples. Examples include ethylene sulfate salts (e.g., ADEKA Corporation, product names: Adekarya Soap SR-10, SR-20, SR-30, etc.), bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salts (e.g., Nippon Emulsifier Co., Ltd., product name: Antox MS-60, etc.), allyloxymethyl alkoxyethyl hydroxypolyoxyethylene (e.g., ADEKA Corporation, product names: Adekarya Soap ER-10, ER-20, etc.), polyoxyethylene alkylpropenylphenyl ethers (e.g., Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon RN-20, etc.), allyloxymethyl nonylphenoxyethyl hydroxypolyoxyethylene (e.g., ADEKA Corporation, product name: Adekarya Soap NE-10, etc.). Of the emulsifiers mentioned above, allyloxymethyl alkoxyethyl hydroxypolyoxyethylene sulfate salts [for example, ADEKA Corporation, product names: Adekaria Soap SR-10, SR-20, SR-30, etc.] are more preferred from the viewpoint of pigment dispersibility, adhesion, and scratch resistance.

[0089] The amount of emulsifier per 100 parts by mass of monomer components constituting polymer (A) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 2 parts by mass or more, and particularly preferably 3 parts by mass or more, from the viewpoint of improving polymerization stability, and preferably 10 parts by mass or less, more preferably 6 parts by mass or less, from the viewpoint of improving water resistance, scratch resistance, and blocking resistance.

[0090] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the amount of emulsifier per 100 parts by mass of the inner layer monomer component is preferably 0.01 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, from the viewpoint of improving polymerization stability, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate and scratch resistance.

[0091] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the amount of emulsifier per 100 parts by mass of the monomer component for the outer layer is preferably 0.01 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, from the viewpoint of improving polymerization stability, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate and scratch resistance.

[0092] Examples of polymerization initiators for polymerizing polymer (A) of the present disclosure include azobisisobutyronitrile, 2,2-A Examples include azo compounds such as zobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-diaminopropane) hydrochloride, 4,4-azobis(4-cyanovaleric acid), and 2,2-azobis(2-methylpropionamidine); persulfates such as ammonium persulfate and potassium persulfate; and peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide, but are not limited to these examples. These polymerization initiators may be used individually or in combination of two or more types.

[0093] From the viewpoint of increasing the polymerization rate and reducing the amount of unreacted monomer components remaining, the amount of polymerization initiator per 100 parts by mass of monomer components constituting polymer (A) is preferably 0.05 parts by mass. The amount is 1 part by mass or more, more preferably 0.1 parts by mass or more, and from the viewpoint of improving water resistance, it is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less.

[0094] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the amount of polymerization initiator per 100 parts by mass of inner layer monomer component is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, from the viewpoint of increasing the polymerization rate and reducing the amount of unreacted inner layer monomer component remaining, and preferably 1 part by mass or less, more preferably 0.8 parts by mass or less, and even more preferably 0.5 parts by mass or less, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate and scratch resistance.

[0095] When the polymer (A) of the present disclosure is an emulsion particle having a multilayer structure, the amount of polymerization initiator per 100 parts by mass of the outer layer monomer component is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, from the viewpoint of increasing the polymerization rate and reducing the amount of unreacted inner layer monomer component remaining, and preferably 1 part by mass or less, more preferably 0.8 parts by mass or less, and even more preferably 0.5 parts by mass or less, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate and scratch resistance.

[0096] The method of adding the polymerization initiator is not particularly limited. Examples of such methods include single-charge addition, divided addition, and continuous dropwise addition. Furthermore, from the viewpoint of accelerating the completion of the polymerization reaction, a portion of the polymerization initiator may be added before or after the completion of the addition of monomer components to the reaction system.

[0097] Furthermore, in order to promote the decomposition of the polymerization initiator, appropriate amounts of a decomposing agent for the polymerization initiator, such as a reducing agent like sodium bisulfite or a transition metal salt like ferrous sulfate, may be added to the reaction system.

[0098] Furthermore, a chain transfer agent can be used to adjust the weight-average molecular weight of the emulsion particles. Examples of chain transfer agents include, but are not limited to, 2-ethylhexyl thioglycolate, tert-dodecyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, α-methylstyrene, and α-methylstyrene dimer. These chain transfer agents may be used individually or in combination of two or more. From the viewpoint of appropriately adjusting the weight-average molecular weight of the emulsion particles, the amount of chain transfer agent per 100 parts by mass of monomer component is preferably 0.01 to 10 parts by mass.

[0099] Furthermore, additives such as pH buffers, chelating agents, and film-forming aids may be added to the reaction system as needed. The amount of additive varies depending on its type and cannot be determined in general terms. Typically, the amount of additive per 100 parts by mass of monomer component is preferably about 0.01 to 5 parts by mass, more preferably about 0.1 to 3 parts by mass.

[0100] The atmosphere used when emulsion polymerization of monomer components is not particularly limited, but from the viewpoint of improving the efficiency of polymerization initiators, an inert gas such as nitrogen gas is preferred.

[0101] The polymerization temperature when emulsion polymerization of monomer components is not particularly limited, but is usually preferably 50 to 100°C, more preferably 60 to 95°C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

[0102] There are no particular limitations on the polymerization time for emulsion polymerization of monomer components; it can be set appropriately according to the progress of the polymerization reaction, but it is usually around 2 to 9 hours.

[0103] Furthermore, when emulsion polymerization of monomer components, some or all of the acidic groups of the resulting polymer component may be neutralized with a neutralizing agent. The neutralizing agent may be used after the addition of monomer components in the final stage, for example, between the first and second polymerization reactions, or at the end of the initial emulsion polymerization reaction.

[0104] Examples of neutralizing agents include alkali metal or alkaline earth metal hydroxides such as sodium hydroxide; alkali metal or alkaline earth metal carbonides such as sodium bicarbonate and calcium carbonate; and alkaline substances such as organic amines such as ammonia, monomethylamine, and dimethylaminoethanol, but are not limited to these examples. Among these neutralizing agents, volatile alkaline substances such as ammonia are preferred from the viewpoint of improving water resistance, and sodium bicarbonate is preferred from the viewpoint of improving the storage stability of emulsion particles. The neutralizing agent can be used, for example, as an aqueous solution.

[0105] When forming an outer layer on the emulsion particles obtained above, it is preferable, from the viewpoint of forming a layer separation structure within the emulsion particles, to emulsion polymerize the monomer components constituting the outer layer after the polymerization reaction rate during the production of the emulsion particles reaches 90% or more, preferably 95% or more.

[0106] Furthermore, after forming the inner layer of the emulsion particles but before forming the outer layer, a layer made of other polymer components may be formed as necessary, within a range that does not hinder the objectives of the present invention. Therefore, when manufacturing the emulsion particles contained in the aqueous ink emulsion of the present invention, after forming the inner layer of the emulsion particles but before forming the outer layer, a layer made of other polymer components may be formed as necessary, within a range that does not hinder the objectives of the present invention.

[0107] The monomer components used to form the outer layer can be the same as the monomer components used as raw materials for the inner layer of the emulsion particles. Furthermore, the emulsion polymerization method and polymerization conditions for forming the outer layer can be the same as the method and polymerization conditions for producing the inner layer of the emulsion particles.

[0108] As described above, emulsion particles having an inner layer and an outer layer can be obtained. Furthermore, a surface layer made of other polymer components may be further formed on the surface of the outer layer, as necessary, within a range that does not hinder the objectives of the present invention.

[0109] As described above, emulsion particles having an inner layer and an outer layer can be obtained. Furthermore, a surface layer made of other polymer components may be further formed on the surface of the outer layer, as necessary, within a range that does not hinder the objectives of the present invention.

[0110] The above emulsion can be further enhanced with crosslinking properties by including a crosslinking agent. The crosslinking agent may be one that initiates the crosslinking reaction at room temperature or one that initiates the crosslinking reaction with heat. In the aqueous ink emulsion of the present invention, the blocking resistance and adhesion can be further improved by including a crosslinking agent in the emulsion particles.

[0111] Suitable crosslinking agents include, for example, oxazoline group-containing compounds, isocyanate group-containing compounds, aminoplast resins, epoxy group-containing compounds, carbodiimide group-containing compounds, and silane group-containing compounds. These crosslinking agents may be used individually or in combination of two or more. Among these crosslinking agents, oxazoline group-containing compounds and carbodiimide group-containing compounds are preferred from the viewpoint of improving the storage stability of the aqueous ink emulsion of the present invention. Furthermore, carbodiimide group-containing compounds are preferred from the viewpoint of improving the storage stability of the aqueous ink emulsion of the present invention and the strength of the coating film during low-temperature drying. Low temperature as used herein may be 120°C or lower, 110°C or lower, or 100°C or lower.

[0112] Examples of crosslinking agents in this disclosure include oxazoline group-containing compounds, epoxy group-containing compounds, carbodiimide group-containing compounds, isocyanate group-containing compounds, and silane group-containing compounds. These crosslinking agents may be used individually or in combination of two or more. Among these crosslinking agents, the aqueous crosslinking agent of the present invention is particularly useful. From the viewpoint of improving the storage stability of the ink emulsion, oxazoline group-containing compounds, epoxy group-containing compounds, and carbodiimide group-containing compounds are preferred, oxazoline group-containing compounds and carbodiimide group-containing compounds are more preferred, and carbodiimide group-containing compounds are even more preferred from the viewpoint of storage stability and crosslinking properties at low temperatures. The crosslinking agents of this disclosure may be used individually or in combination of two or more types.

[0113] Examples of oxazoline group-containing compounds in this disclosure include 2,2'-bis(2-oxazoline), 2,2'-methylene-bis(2-oxazoline), 2,2'-ethylene-bis(2-oxazoline), 2,2'-trimethylene-bis(2-oxazoline), 2,2'-tetramethylene-bis(2-oxazoline), 2,2'-hexamethylene-bis(2-oxazoline), and 2,2'-octamethylene-bis(2-oxazoline). Examples include 2,2'-ethylene-bis(4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis(2-oxazoline), 2,2'-m-phenylene-bis(2-oxazoline), 2,2'-m-phenylene-bis(4,4'-dimethyl-2-oxazoline), bis(2-oxazolinylcyclohexane) sulfide, bis(2-oxazolinylnorbornane) sulfide, and oxazoline ring-containing polymers. Examples of oxazoline group-containing compounds include commercially available products from Nippon Shokubai Co., Ltd., such as Epocross WS-300, Epocross WS-500, Epocross WS-700, Epocross K-2010, Epocross K-2020, and Epocross K-2030. Examples of epoxy group-containing compounds in this disclosure include polyglycidyl ethers such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin triglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, and hydrogenated bisphenol A type diglycidyl ether.

[0114] Examples of carbodiimide group-containing compounds in this disclosure include aromatic carbodiimide compounds and aliphatic carbodiimide compounds. Examples of commercially available carbodiimide group-containing compounds in this disclosure include Carbodilite SV-02, Carbodilite V-02, Carbodilite V-02-L2, Carbodilite V-04, Carbodilite V-06, Carbodilite V-10, Carbodilite SW-12G, Carbodilite E-02, and Carbodilite E-05 (all trade names). Examples of isocyanate group-containing compounds of this disclosure include aromatic polyisocyanates such as xylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, and tolylene diisocyanate; aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated aromatic polyisocyanates; dimers or trimers of these polyisocyanates; and adduct compounds consisting of these polyisocyanates and polyols such as trimethylolpropane. These isocyanate group-containing compounds can be used individually or in combination of two or more. Furthermore, as an isocyanate group-containing compound, a blocked isocyanate compound may be used, in which the active isocyanate group in the polyisocyanate compound has been pre-reacted with a blocking agent such as phenol to inactivate it. Using a blocked isocyanate compound can improve the storage stability of the aqueous dispersion of the present invention and the ink using it.

[0115] Examples of silane group-containing compounds in this disclosure include alkoxysilane compounds such as bis-(3-triethoxysilylpropyl)-tetrasulfan, bis-(3-triethoxysilylpropyl)-disulfan, and ethoxysiloxane oligomers, as well as hydrolysates of these alkoxysilane compounds. The isocyanate group-containing compounds of this disclosure include, for example, "Coronate L," "Coronate HX," "Coronate HL," "Coronate HL-S," "Coronate 2234," "Aquanate 105," "Aquanate 130," "Aquanate 140," "Aquanate 200," "Aquanate 210" (all manufactured by Tosoh Corporation; "Coronate" and "Aquanate" are registered trademarks), "Desmodule N3400" (manufactured by Sumitomo Bayer Urethane Co., Ltd. (now Bayer AG); "Desmodule" is a registered trademark), "Duranate D-201," "Duranate TSE-100," "Duranate TSS-100," "Duranate 24A-100," and "Duranate E-405-8." Examples of commercially available products include "0T", "Duranate WB40-100", "Duranate WB40-80D", "Duranate WT20-100", "Duranate WT30-100", "Duranate WT31-100", "Duranate WL70-100", "Duranate WR80-70P", "Duranate WE50-100", "Duranate WM44-L70G", [all manufactured by Asahi Kasei Chemicals Corporation, "Duranate" is a registered trademark], "Takenate D-110N", "Takenate D-120N", "Takenate M-631N", and "MTERT-Orestar NP1200", [all manufactured by Mitsui Chemicals Polyurethane, Inc., "Takenate" and "Orestar" are registered trademarks].

[0116] The crosslinking agent of this disclosure may contain multiple functional groups. The amount of functional groups contained in the crosslinking agent of this disclosure is preferably 100 g / mol or more, more preferably 150 g / mol or more, even more preferably 200 g / mol or more, preferably 700 g / mol or less, more preferably 650 g / mol or less, and even more preferably 600 g / mol or less. Functional groups included in the crosslinking agent of this disclosure include oxazoline groups, epoxy groups, carbodiimide groups, isocyanate groups, silane groups, and the like.

[0117] The functional groups contained in the crosslinking agent of this disclosure can react with reactive groups that react with the functional groups contained in the crosslinking agent of the main component (polymer (A) and wax component (B)), thereby forming a crosslinked structure. Reactive groups that react with the functional groups of the crosslinking agent of this disclosure include acid groups, hydroxyl groups, and amino groups. Examples of acid groups include carboxyl groups, sulfonic acid groups, and phosphate groups, with carboxyl groups being more preferred. The one-to-one equivalent number of the functional groups of the crosslinking agent in this disclosure and the main component (polymer (A) and / or wax component (B)) can be calculated, for example, from the following formula. Amount of crosslinking agent = Reactive group of main ingredient / (56.1 × 1000) × Equivalent amount of crosslinking agent × Amount of main ingredient The amount of crosslinking agent is preferably 0.1 to 5 times the obtained value, from the viewpoint of improving storage stability, scratch resistance, adhesion, blocking resistance, and cellophane tape peel resistance. The amount of functional groups contained in the crosslinking agent can be measured by known methods depending on the type of functional group, or by referring to catalog values, or by freeze-drying the polymer solution and analyzing it by 1H-NMR, and calculating the amount of each functional group from the absorption peak intensity derived from each functional group and the absorption peak intensity derived from other monomers.

[0118] <Wax component (B)> The aqueous dispersion of this disclosure contains wax component (B).

[0119] The wax component (B) of this disclosure may include natural waxes and synthetic waxes.

[0120] Examples of natural waxes include petroleum-based waxes, plant-based waxes, and animal / plant-based waxes. Examples of petroleum-based waxes include paraffin wax, microcrystalline wax, and petrolatum. Examples of plant-based waxes include carnauba wax, candelilla wax, rice wax, and wood wax. Examples of animal / plant-based waxes include lanolin and beeswax.

[0121] Examples of synthetic waxes include synthetic hydrocarbon waxes and modified waxes. Examples of synthetic hydrocarbon waxes include polyolefin waxes, (meth)acrylic waxes, and Fischer-Tropsch waxes. Examples of modified waxes include paraffin wax derivatives, montan wax derivatives, and microcrystalline wax derivatives. From the viewpoint of improving adhesion and scratch resistance, polyolefin waxes and (meth)acrylic waxes are preferred.

[0122] The (meth)acrylic wax is not particularly limited and may be manufactured using a monomer having an alkyl group with 10 or more carbon atoms. Examples of (meth)acrylic monomers having an alkyl group with 10 or more carbon atoms include lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, or polymers manufactured from derivatives thereof.

[0123] Commercially available (meth)acrylic waxes can also be used. Preferred commercial products include ST100 and ST200 manufactured by Nippon Shokubai Co., Ltd.

[0124] Polyolefin waxes are not particularly limited and include, for example, waxes and copolymers made from olefins or their derivatives such as ethylene, propylene, and butylene. Specifically, examples include polyethylene waxes, polypropylene waxes, polybutylene waxes, copolymer waxes made of ethylene and monomers having carboxylic acid groups such as methacrylic acid or acrylic acid, and oxidized polyethylene waxes. Among these, polyethylene waxes, polypropylene waxes, copolymer waxes made of ethylene and monomers having carboxylic acid groups such as methacrylic acid or acrylic acid, and oxidized polyethylene waxes are preferred from the viewpoint of improving adhesion and scratch resistance.

[0125] The oxidized polyethylene wax of this disclosure is obtained by oxidizing polyethylene wax and has a polyethylene-derived skeleton (polyethylene skeleton). The polyethylene skeleton mainly has structural units derived from ethylene. The polyethylene skeleton may be a homopolyethylene (a homopolymer of ethylene) skeleton, a block polyethylene (a block copolymer of ethylene and another olefin) skeleton, or a random polyethylene (a random copolymer of ethylene and another olefin) skeleton. Examples of other olefins include alkenes such as propylene, isobutylene, 1-butene, 1-pentene, and 1-hexene. These components may be linear or branched. The number of carbon atoms in the other olefin components is, for example, 2 to 6.

[0126] The ethylene content (content of structural units derived from ethylene) in the polyethylene skeleton is, for example, 60 mol% or more, and may be 70 mol% or more. If the polyethylene skeleton is a block polyethylene skeleton or a random polyethylene skeleton, the ethylene content (content of structural units derived from ethylene) in the polyethylene skeleton is, for example, 95 mol% or less, and may be 90 mol% or less.

[0127] From the viewpoint of obtaining better adhesion and scratch resistance, the polyethylene oxide wax preferably includes high-density polyethylene oxide wax.

[0128] Commercially available polyethylene oxide waxes can also be used. Preferred commercial products include BYK's AQUACER497, AQUACER515, AQUACER531, and AQUACER1547.

[0129] The wax component (B) can be used alone or in combination of two or more types.

[0130] The wax component (B) of this disclosure is preferably in the form of solid wax particles dissolved or dispersed in a solvent, and more preferably in the form of an emulsion dispersed in a solvent. The solvent is preferably an aqueous medium, and more preferably the same aqueous medium used as the solvent for an aqueous ink composition.

[0131] The volume-average particle diameter (nm) of the wax particles in this disclosure is preferably 25 nm or more and 500 nm or less, and more preferably 30 nm or more and 400 nm or less. While not particularly limited, it can be measured by methods such as dynamic light scattering, laser diffraction / scattering, Coulter counters, and microscopy.

[0132] The average particle diameter described in this embodiment is the average particle diameter (hydrodynamic diameter) obtained by cumulant analysis using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], which is a particle diameter measurement device using dynamic light scattering, after determining the autocorrelation function by photon correlation.

[0133] From the viewpoint of adhesion, the melting point of the wax component (B) of this disclosure is preferably 20°C or higher, more preferably 25°C or higher, even more preferably 30°C or higher, preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower. The melting point (Tm2) of the wax component (B) can be measured by a melting point measuring device in accordance with JIS K 0064 or the like.

[0134] The acid value (mgKOH / g) of the wax component in this disclosure may or may not be present from the viewpoint of adhesion, but is preferably 0 mgKOH / g, preferably 100 mgKOH / g or less, more preferably 90 mgKOH / g or less, and even more preferably 80 mgKOH / g or less. <Aqueous dispersion> The content of polymer (A) in 100 parts by mass of the nonvolatile content of the aqueous dispersion of this disclosure may be 80 parts by mass or more, preferably 82 parts by mass or more, more preferably 85 parts by mass or more, may be 99 parts by mass or less, preferably 98 parts by mass or less, and more preferably 95 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0135] The non-volatile content of the aqueous dispersion of this disclosure may be calculated as the total mass of the aqueous dispersion minus the mass of volatile components contained in the resin and various additives, or by weighing 1 g of the aqueous dispersion, drying it in a hot air dryer at a temperature of 110°C for 1 hour, and using the resulting residue as the non-volatile content, formula: [Non-volatile content (mass%) in aqueous resin dispersions] = ([Mass of residue] ÷ [1g of aqueous resin dispersion]) × 100 It may also be calculated based on this.

[0136] The total content of polymer (A) and wax component (B) in 100 parts by mass of the nonvolatile content of the aqueous dispersion of this disclosure may be 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, may be 25 parts by mass or less, preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0137] The content of wax component (B) in 100 parts by mass of nonvolatile matter of the aqueous dispersion of this disclosure may be 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, may be 25 parts by mass or less, preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0138] The mass ratio of polymer (A) to wax component (B) of the present disclosure may be 99 / 1 to 80 / 20, preferably 99 / 1 to 82 / 18, and more preferably 99 / 1 to 85 / 15, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0139] The mass ratio of structural units derived from the cyclic aliphatic group-containing monomer of this disclosure to the wax component (B) may be 99 / 1 to 55 / 45, preferably 99 / 1 to 60 / 40, and more preferably 99 / 1 to 65 / 35, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0140] The content of polymer (A) in 100 parts by mass of the aqueous dispersion of this disclosure may be 20 parts by mass or more, preferably 30 parts by mass or more, more preferably 35 parts by mass or more, may be 70 parts by mass or less, preferably 60 parts by mass or less, and more preferably 50 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0141] The content of wax component (B) in 100 parts by mass of the aqueous dispersion of this disclosure may be 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, may be 20 parts by mass or less, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0142] In the nonvolatile components of the aqueous dispersion of this disclosure, the content of polymer (A) in 100 parts by mass of the total of polymer (A) and wax component (B) is preferably 80 parts by mass or more, more preferably 85 parts by mass or more, even more preferably 90 parts by mass or more, preferably 99 parts by mass or less, more preferably 97 parts by mass or less, and even more preferably 95 parts by mass or less.

[0143] In the nonvolatile components of the aqueous dispersion of the present disclosure, the content of wax component (B) in 100 parts by mass of the total of polymer (A) and wax component (B) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less.

[0144] The aqueous dispersion of this disclosure may contain resins other than polymer (A) or wax component (B), such as resin emulsions, water-soluble resins, and water-dispersible resins, to the extent that the objectives of the present invention are not hindered. Furthermore, the aqueous dispersion of this disclosure may contain, in appropriate amounts, additives such as surfactants, film-forming aids, ultraviolet absorbers, ultraviolet inhibitors, fillers, leveling agents, dispersants, thickeners, wetting agents, plasticizers, stabilizers, antioxidants, and preservatives, provided that the objectives of the present invention are not hindered.

[0145] When the aqueous dispersion of the present disclosure contains a crosslinking agent, the total content of polymer (A) and / or wax component (B) and crosslinking agent in 100 parts by mass of the aqueous dispersion of the present disclosure may be 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, may be 60 parts by mass or less, preferably 55 parts by mass or less, and more preferably 50 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance. The amount of crosslinking agent in 100 parts by mass of the nonvolatile content of the aqueous dispersion of this disclosure may be 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, may be 25 parts by mass or less, preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, from the viewpoint of adhesion, scratch resistance, and blocking resistance. The mass ratio of the polymer (A) and wax component (B) of this disclosure to the crosslinking agent may be 99 / 1 to 80 / 20, preferably 99 / 1 to 82 / 18, and more preferably 99 / 1 to 85 / 15, from the viewpoint of adhesion, scratch resistance, and blocking resistance. It is preferable that the polymer (A) and / or wax component (B) of this disclosure have structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent. Reactive groups that react with the functional groups of the crosslinking agent of this disclosure include acid groups, hydroxyl groups, amino groups, etc. Examples of acid groups include carboxyl groups, sulfonic acid groups, phosphate groups, etc., with carboxyl groups being more preferred.

[0146] When the polymer (A) and / or wax component (B) of this disclosure have structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent, the mass ratio of structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent to the crosslinking agent may be 99 / 1 to 55 / 45, preferably 99 / 1 to 60 / 40, and more preferably 99 / 1 to 65 / 35, from the viewpoint of adhesion, scratch resistance, and blocking resistance. When structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent are contained in both the polymer (A) and the wax component (B), the mass of structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent in the polymer (A) and the wax component (B) is used to calculate the ratio. When structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent are contained in only the polymer (A) or only the wax component (B), the mass of the component containing the structural units derived from reactive group-containing monomers that react with the functional groups of the crosslinking agent is used to calculate the ratio. When the polymer (A) and / or wax component (B) of this disclosure have structural units derived from acid group-containing monomers, the mass ratio of the acid group-containing monomer-derived structural units to the crosslinking agent may be 99 / 1 to 55 / 45, preferably 99 / 1 to 60 / 40, and more preferably 99 / 1 to 65 / 35, from the viewpoint of adhesion, scratch resistance, and blocking resistance. When the acid group-containing monomer-derived structural units are contained in both the polymer (A) and the wax component (B), the mass of the acid group-containing monomer-derived structural units in the polymer (A) and the wax component (B) is used to calculate the ratio. When the acid group-containing monomer-derived structural units are contained in only the polymer (A) or only the wax component (B), the mass of the component containing the acid group-containing monomer-derived structural units is used to calculate the ratio.

[0147] When the polymer (A) and / or wax component (B) of this disclosure have structural units derived from hydroxyl group-containing monomers, the mass ratio of structural units derived from hydroxyl group-containing monomers to the crosslinking agent may be 99 / 1 to 55 / 45, preferably 99 / 1 to 60 / 40, and more preferably 99 / 1 to 65 / 35, from the viewpoint of adhesion, scratch resistance, and blocking resistance. When structural units derived from hydroxyl group-containing monomers are contained in both polymer (A) and wax component (B), the mass of structural units derived from hydroxyl group-containing monomers in polymer (A) and wax component (B) is used to calculate the ratio. When structural units derived from hydroxyl group-containing monomers are contained in only polymer (A) or only wax component (B), the mass of the component containing the structural units derived from hydroxyl group-containing monomers is used to calculate the ratio. In the nonvolatile components of the aqueous dispersion of this disclosure, the content of polymer (A) in 100 parts by mass of the total of (polymer (A) and wax component (B)) and crosslinking agent is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, even more preferably 60 parts by mass or more, preferably 99 parts by mass or less, more preferably 97 parts by mass or less, and even more preferably 95 parts by mass or less. In the nonvolatile components of the aqueous dispersion of the present disclosure, the content of the crosslinking agent in a total of 100 parts by mass of (polymer (A) and wax component (B)) and the crosslinking agent is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less. The volume-average particle size (nm) of the aqueous dispersion of this disclosure is preferably 25 nm to 500 nm, more preferably 50 nm to 400 nm, and most preferably 100 nm to 300 nm, from the viewpoint of blocking resistance, adhesion to the substrate, scratch resistance, discharge stability, and image quality improvement. The volume-average particle size of an aqueous dispersion is not particularly limited, but can be measured by dynamic light scattering, laser diffraction / scattering, Coulter counter, microscopy, etc. The average particle diameter in this disclosure is the average particle diameter (hydrodynamic diameter) obtained by cumulant analysis using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], which is a particle diameter measurement device using dynamic light scattering, and by determining the autocorrelation function using the photon correlation method.

[0148] <Water-based ink> The aqueous dispersion of this disclosure can be suitably used in aqueous inks.

[0149] When used in a white ink, the polymer (A) content in 100 parts by mass of the aqueous ink of this disclosure may be 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, may be 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of discharge stability, storage stability, and dispersion stability. On the other hand, when used in a color ink other than a white ink, the polymer (A) content may be 1 part by mass or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, may be 40 parts by mass or less, preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of discharge stability and storage stability.

[0150] The content of wax component (B) in 100 parts by mass of the aqueous ink of this disclosure may be 0.01 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, may be 8 parts by mass or less, preferably 6 parts by mass or less, and more preferably 4 parts by mass or less, from the viewpoint of discharge stability and storage stability.

[0151] The mass ratio of polymer (A) to wax component (B) in the present disclosure may be 99 / 1 to 80 / 20, preferably 99 / 1 to 82 / 18, and more preferably 99 / 1 to 85 / 15, from the viewpoint of adhesion, scratch resistance, and blocking resistance. The mass ratio of structural units derived from cyclic aliphatic group-containing monomers to wax component (B) in the aqueous ink of the present disclosure may be 99 / 1 to 55 / 45, preferably 99 / 1 to 60 / 40, and more preferably 99 / 1 to 65 / 35, from the viewpoint of adhesion, scratch resistance, and blocking resistance. When the aqueous ink of this disclosure contains a crosslinking agent, the amount of the crosslinking agent per 100 parts by mass of the aqueous ink of this disclosure may be 0.01 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, may be 8 parts by mass or less, preferably 6 parts by mass or less, and more preferably 4 parts by mass or less, from the viewpoint of discharge stability and storage stability. The mass ratio of polymer (A) to crosslinking agent of the present disclosure may be 99 / 1 to 80 / 20, preferably 99 / 1 to 82 / 18, and more preferably 99 / 1 to 85 / 15, from the viewpoint of adhesion, scratch resistance, and blocking resistance. The mass ratio of structural units derived from cyclic aliphatic group-containing monomers to the crosslinking agent in the aqueous ink of this disclosure may be 99 / 1 to 55 / 45, preferably 99 / 1 to 60 / 40, and more preferably 99 / 1 to 65 / 35, from the viewpoint of adhesion, scratch resistance, and blocking resistance.

[0152] The aqueous inks of this disclosure contain colorants. Examples of colorants include achromatic colors such as white, black, and gray, and chromatic colors such as yellow, magenta, cyan, blue, red, orange, and green, but the aqueous inks of this disclosure are not limited to these examples.

[0153] Examples of colorants in this disclosure include pigments and dyes. Among these, pigments are preferred due to their excellent weather resistance. When using pigments, they may be used, for example, in the form of a pigment dispersion such as a paste. Examples of pigments include organic pigments and inorganic pigments, which may be used individually or in combination.

[0154] Examples of dyes include CI Solvent Black, CI Solvent Red, CI Solvent Yellow, CI Solvent Blue, CI Solvent Green, CI Solvent Orange, and CI Solvent Violet, but the present invention is not limited to these examples.

[0155] Examples of organic pigments include azo pigments such as benzidine and Hansa Yellow, azomethine pigments, methine pigments, anthraquinone pigments, phthalocyanine pigments such as phthalocyanine blue, perinone pigments, perylene pigments, diketopyrrolopyrrole pigments, thioindigo pigments, iminoisoindoline pigments, iminoisoindolinone pigments, quinacridone pigments such as quinacridone red and quinacridone violet, flavanthron pigments, indanthron pigments, anthrapyrimidine pigments, carbazole pigments, monoallylide yellow, diallylide yellow, benzimimidazolone yellow, toryl orange, naphthol orange, and quinophthalone pigments, but the present invention is not limited to these examples. These organic pigments may be used individually or in combination of two or more types. Preferred organic pigments include, for example, CI Pigment Yellow, CI Pigment Red, CI Pigment Orange, CI Pigment Violet, CI Pigment Blue, and CI Pigment Green.

[0156] Examples of inorganic pigments include titanium dioxide, antimony trioxide, zinc oxide, lithopone, lead white, red iron oxide, black iron oxide, iron oxide, chromium oxide green, carbon black, lead yellow, molybdenum red, ferric ferrocyanide (Prussian blue), ultramarine, lead chromate, and other pigments with a flattened shape such as mica, clay, aluminum powder, talc, and aluminum silicate, as well as extender pigments such as calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, and magnesium carbonate. However, the present invention is not limited to these examples. These inorganic pigments may be used individually or in combination of two or more types.

[0157] The colorant used in the aqueous ink of this disclosure is preferably one colorant selected from white pigment, yellow, magenta, cyan, black, red, blue, and green.

[0158] There are no particular limitations on the white pigment, and any known inorganic white pigment can be used. Examples include silicas such as alkaline earth metal sulfates, carbonates, finely powdered silicic acid, and synthetic silicates, calcium silicate, alumina, alumina hydrate, titanium dioxide, zinc oxide, talc, and clay. Furthermore, the inorganic white pigment may be surface-treated by various surface treatment methods. Among these, surface-treated titanium dioxide is preferred because it exhibits relatively good dispersibility in aqueous media. For example, to avoid the influence of photocatalysis, titanium dioxide surface-treated with inorganic materials is preferred, and titanium dioxide surface-treated with silica and alumina is preferred. Moreover, it is also preferable to use titanium dioxide that has been surface-treated with a silane coupling agent after being surface-treated with silica and alumina. In titanium dioxide surface-treated with silica and alumina, known rutile-type and anatase-type titanium dioxide can be used as titanium dioxide, and rutile-type titanium dioxide is more preferred.

[0159] Furthermore, the average particle size of the titanium dioxide is preferably 100 to 500 nm, and more preferably 150 to 400 nm. If the average particle size is 100 nm or less, non-settling and dispersion stability in aqueous media are more easily achieved, but the whiteness and opacity will be inferior, which may reduce the practical usability as a white ink. On the other hand, if the average particle size is 500 nm or more, there are no problems in terms of whiteness and opacity, but the discharge stability tends to be insufficient. For practical purposes, a particle size of 200 to 300 nm is even more preferable. The average particle size of the titanium dioxide used as a raw material is determined by taking the average of 20 particle size measurements using electron microscope images.

[0160] In this invention, the average particle size of the polymer (A) and wax component (B), the aqueous dispersion containing (A) and (B), and the aqueous ink using the aqueous dispersion containing (A) and (B) are not particularly limited, but can be measured by dynamic light scattering, laser diffraction / scattering, Coulter counter, microscopy, etc.

[0161] The average particle diameter described in this embodiment is the average particle diameter (hydrodynamic diameter) obtained by cumulant analysis using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], which is a particle diameter measurement device using dynamic light scattering, after determining the autocorrelation function by photon correlation.

[0162] Organic pigments for yellow include CI Pigment Yellow 1 (Hansa Yellow G), 2, 3 (Hansa Yellow 10G), 4, 5 (Hansa Yellow 5G), 6, 7, 10, 11, 12 (Disazo Yellow AAA), 13, 14, 16, 17, 24 (Flavantron Yellow), 55 (Disazo Yellow AAPT), 61, 61:1, 65, 73, 74 (Fast Yellow 5GX), 75, 81, 83 (Disazo Yellow HR), 93 (Condensed Azo Yellow 3G), 94 (Condensed Azo Yellow 6G), 95 (Condensed Azo Yellow GR), 97 (Fast Yellow FGL), 98, 99 (Anthraquinone), 100, 108 (Anthrapyrimidine Yellow), 109 (Isoindo Examples include Linone Yellow 2GLT), 110 (Isoindolinone Yellow 3RLT), 113, 117, 120 (Benzimidazolone Yellow H2G), 123 (Anthraquinone Yellow), 124, 128 (Condensed Azo Yellow 8G), 129, 133, 138 (Quinophthalone Yellow), 139 (Isoindolinone Yellow), 147, 151 (Benzimidazolone Yellow H4G), 153 (Nickel Nitroso Yellow), 154 (Benzimidazolone Yellow H3G), 155, 156 (Benzimidazolone Yellow HLR), 167, 168, 172, 173 (Isoindolinone Yellow 6GL), and 180 (Benzimidazolone Yellow).

[0163] Organic pigments for magenta water-based inks include CI Pigment Red 1 (Para Red), 2, 3 (Toluidine Red), 4, 5 (ITR Red), 6,7,8,9,10,11,12,14,15,16,17,18,19,21,22,23,30,31,32,37,38 (Pyrazolone Red B), 40,41,42,88 (Thioindigo Bordeaux), 112 (Naphthol Red FGR), 114 (Brilliant Carmine BS), 122 (Dimethylquinacridone), 123 (Perylene Vermilion), 144,146,149 (Perylene Scarlet), 150,166,168 (Anthanthrone Orange), 170 (Naphthol Red F3RK), 171 (Benzimidazolone Maroon HFM), 175 (Benzimidazolone Red HFT), 176 (Benzimidazolone Carmine Examples include HF3C), 177, 178 (Perylene Red), 179 (Perylene Maroon), 185 (Benzimidazolone Carmine HF4C), 187, 188, 189 (Perylene Red), 190 (Perylene Red), 194 (Perinon Red), 202 (Quinacridone Magenta), 209 (Dichloroquinacridone Red), 214 (Condensed Azo Red), 216, 219, 220 (Condensed Azo), 224 (Perylene Red), 242 (Condensed Azo Scarlet), 245 (Naphthol Red), or CI Pigment Violet 19 (Quinacridone), 23 (Dioxazine Violet), 31, 32, 33, 36, 38, 43, 50, etc.

[0164] Examples of organic pigments for cyan include CI Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6 (all phthalocyanine blue), 16 (metal-free phthalocyanine blue), 17:1, 18 (alkaline blue toner), 19, 21, 22, 25, 56, 60 (Slub blue), 64 (dichloroindanthron blue), 65 (biolanthron), and 66 (indigo).

[0165] For black pigments, black organic pigments such as aniline black (CI Pigment Black 1) can be used.

[0166] Organic pigments used in water-based color inks other than white pigment, yellow, cyan, or magenta water-based inks include CI Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16 (Vulcan Orange), 24, 31 (Condensed Azo Orange 4R), 34, 36 (Benzimidazolone Orange HL), 38, 40 (Pyrantron Orange), 42 (Isoindolinone Orange RLT), 43, 51, 60 (Benzimidazolone-based insoluble monoazo pigment), 62 (Ben Examples include bisimidazolone-based insoluble monoazo pigments), 63; CI Pigment Green 7 (phthalocyanine green), 10 (green gold), 36 (salt-brominated phthalocyanine green), 37, 47 (violantron green); or CI Pigment Brown 1, 2, 3, 5, 23 (condensed azo brown 5R), 25 (benzimidazolone brown HFR), 26 (perylene bordeaux), 32 (benzimidazolone brown HFL), etc.

[0167] The amount of colorant per 100 parts by mass of nonvolatile content of the aqueous ink resin emulsion used in the aqueous ink of this disclosure is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, from the viewpoint of sufficiently coloring the print or image formed with the aqueous ink, and preferably 300 parts by mass or less, more preferably 200 parts by mass or less, from the viewpoint of forming a uniform coating film.

[0168] When using a white pigment, the amount of white pigment per 100 parts by mass of nonvolatile content of the aqueous ink resin emulsion is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, from the viewpoint of sufficiently coloring the print or image formed with the aqueous ink and improving color development, and preferably 500 parts by mass or less, more preferably 400 parts by mass or less, from the viewpoint of forming a uniform coating film and / or improving gloss.

[0169] The aqueous inks of this disclosure may contain water or other water-soluble organic solvents from the viewpoint of controlling ink viscosity, wetting spread on the recording medium to be printed, improving image quality, and ejection stability. Examples of water-soluble organic solvents include glycols such as propylene glycol, 1,3-propanediol, glycerin, dipropylene glycol, tripropylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol; monoethylene glycol ethers such as monoethylene glycol monomethyl ether, monoethylene glycol monoethyl ether, monoethylene glycol monopropyl ether, monoethylene glycol monoisopropyl ether, monoethylene glycol monobutyl ether, and monoethylene glycol monoisobutyl ether; monopropylene glycol monomethyl ether, monopropylene glycol monoethyl ether, monopropylene glycol monopropyl ether, monopropylene glycol monoisopropyl ether, and mono Monopropylene glycol ethers such as propylene glycol monobutyl ether and monopropylene glycol monoisobutyl ether; polyethylene glycol ethers such as polyethylene glycol monomethyl ether (moles of EO added = 2-10, preferably 2-4), polyethylene glycol monoethyl ether (moles of EO added = 2-10, preferably 2-4), polyethylene glycol monopropyl ether (moles of EO added = 2-10, preferably 2-4), polyethylene glycol monoisopropyl ether (moles of EO added = 2-10, preferably 2-4), polyethylene glycol monobutyl ether (moles of EO added = 2-10, preferably 2-4), and polyethylene glycol monoisobutyl ether (moles of EO added = 2-10, preferably 2-4);Examples of polypropylene glycol ethers include polypropylene glycol monomethyl ether (number of EO added moles = 2 to 10, preferably 2 to 4), polypropylene glycol monoethyl ether (number of EO added moles = 2 to 10, preferably 2 to 4), polypropylene glycol monopropyl ether (number of EO added moles = 2 to 10, preferably 2 to 4), polypropylene glycol monoisopropyl ether (number of EO added moles = 2 to 10, preferably 2 to 4), polypropylene glycol monobutyl ether (number of EO added moles = 2 to 10, preferably 2 to 4), and polypropylene glycol monoisobutyl ether. Among these, propylene glycol, diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, tripropylene glycol monomethyl ether, monoethylene glycol monoisopropyl ether, and monopropylene glycol monopropyl ether are preferred. These organic solvents may be used individually or in combination of two or more types. ;

[0170] The amount of water-soluble organic solvent varies depending on the type and amount of colorant contained in the water-based ink, and therefore cannot be determined in general terms. It is preferable to determine the amount appropriately according to the type and amount of colorant contained in the water-based ink.

[0171] For example, if the coloring agent contains a white pigment, the amount of organic solvent in 100g of aqueous ink may be 5 parts by mass or more, preferably 8 parts by mass or more, more preferably 10 parts by mass or more, may be 50 parts by mass or less, preferably 45 parts by mass or less, and more preferably 40 parts by mass or less, from the viewpoint of controlling the wetting spread on the recording medium to be printed and improving image quality.

[0172] The aqueous ink of this disclosure contains the resin emulsion for aqueous ink and a colorant, but other resins such as resin emulsions other than the resin emulsion for aqueous ink, water-soluble resins, and water-dispersible resins may be included, as long as the objectives of the present invention are not hindered. Furthermore, the aqueous ink of the present invention may contain appropriate amounts of additives such as surfactants, film-forming aids, ultraviolet absorbers, ultraviolet inhibitors, fillers, leveling agents, dispersants, thickeners, wetting agents, plasticizers, stabilizers, and antioxidants, as long as the objectives of the present invention are not hindered.

[0173] An ionic dispersant is preferred as the dispersant used in the aqueous ink of this disclosure. The content of the dispersant is preferably 0.1% by mass or more and 2.0% by mass or less, and more preferably 0.2% by mass or more and 1.0% by mass or less, per 100 parts by mass of the inkjet ink of the present invention.

[0174] A polymer dispersant is preferred as the dispersant used in the aqueous ink of this disclosure.

[0175] The dispersant used in the aqueous ink of this disclosure may have an acid value. From the viewpoint of redispersibility, the acid value of the dispersant is preferably 350 mg KOH / g or more, more preferably 450 mg KOH / g or more, further preferably 550 mg KOH / g or more, 650 mg KOH / g or more, and 720 mg KOH / g or more, in that order, preferably 1000 mg KOH / g or less, more preferably 900 mg KOH / g or less, and further preferably 850 mg KOH / g or less and 800 mg KOH / g or less. On the other hand, from the viewpoint of lowering the viscosity and conductivity of the aqueous ink, it is preferably 100 mg KOH / g or less, more preferably 50 mg KOH / g or less, and even more preferably 30 mg KOH / g or less. The dispersant does not have to have an acid value, may be 1 mg KOH / g or more, and may be 5 mg KOH / g or more. The volume-average particle size (nm) of the aqueous ink of this disclosure is preferably 25 nm to 500 nm, more preferably 50 nm to 400 nm, and most preferably 100 nm to 300 nm, from the viewpoint of blocking resistance, adhesion to the substrate, scratch resistance, ejection stability, and improved image quality. The volume-average particle size of water-based inks is not particularly limited, but can be measured by methods such as dynamic light scattering, laser diffraction / scattering, Coulter counter, and microscopy. The average particle diameter in this disclosure is the average particle diameter (hydrodynamic diameter) obtained by cumulant analysis using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], which is a particle diameter measurement device using dynamic light scattering, and by determining the autocorrelation function using the photon correlation method.

[0176] The aqueous ink obtained as described above has excellent adhesion and scratch resistance, and can therefore be suitably used as an ink for various applications, such as an inkjet water-based ink, a flexographic printing ink, an offset printing ink, a lithograph printing ink, a gravure printing ink, and a screen printing ink, and is particularly suitable as an inkjet water-based ink.

[0177] The aqueous inks of this disclosure can form prints or images having a predetermined pattern by ejecting the aqueous inks onto a recording medium in a predetermined pattern using, for example, an inkjet recording device.

[0178] Examples of recording media include paper, paper laminated with resin films such as polyethylene, polypropylene, and polystyrene (such as coated paper), metal plates such as aluminum, zinc, and copper, resin films such as cellulose, polyethylene terephthalate, polystyrene, olefin resins, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, nylon, and acrylic resins, paper with a metal coating, and resin films with a metal coating. Resin films are preferred as recording media for printing the aqueous ink of this disclosure, and among these, application to polyethylene terephthalate and olefin resins is preferred.

[0179] Examples of olefin resins include polyethylene and polypropylene, with particular preference for application to polypropylene such as biaxially oriented polypropylene film (OPP) and unoriented polypropylene film (CPP).

[0180] The aqueous ink of this disclosure is preferably formed on a resin film, and the embodiment thereof is a laminate having a printed layer formed from the aqueous ink on the resin film.

[0181] The laminate of this disclosure may or may not have a primer layer between the resin film and the printed layer, but from the viewpoint of productivity it is preferable not to have one, and it is preferable to form the printed layer directly on the resin film. The laminate of this disclosure is laminated in the order of resin film and printed layer, and may or may not have a protective film (laminate layer) on the printed layer, but from the viewpoint of productivity it is preferable not to have one, and by using the aqueous ink of this disclosure it is expected that a laminate with excellent adhesion to the substrate and good scratch resistance can be obtained even without a primer layer or protective film (laminate layer).

[0182] The laminate of this disclosure can be suitably used in various printed materials. [Examples]

[0183] The present invention will now be described in more detail based on examples, but the present invention is not limited to these examples. In the following examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass". <Glass transition temperature of polymer components> The glass transition temperature (Tg) of a polymer component is calculated using the glass transition temperature of the monomer homopolymer used in the monomer components constituting the polymer component, using the formula: 1 / Tg = Σ(Wm / Tgm) / 100 [In the formula, Wm represents the content (mass%) of monomer m in the monomer components constituting the polymer component, and Tgm represents the glass transition temperature (absolute temperature: K) of the monomer m homopolymer.] It was calculated based on Fox's formula, which is expressed as follows:

[0184] <Acid value derived from carboxyl groups in resin emulsion particles> The acid value derived from the carboxyl groups of the resin emulsion particles was approximated by using the number of mg of potassium hydroxide required to neutralize the carboxyl groups present in 1 g of the monomer component used as the acid value. <Minimum film forming temperature> The minimum film formation temperature is measured in accordance with JIS K6828-2:2003, and the measured value is shown. <Average particle size> Using a multi-sample nanoparticle diameter measurement system [manufactured by Otsuka Electronics Co., Ltd., product name: nanoSAQLA], a particle size measurement device using dynamic light scattering at a measurement temperature of 25±0.5℃, the autocorrelation function was determined by photon correlation spectroscopy, and the average particle diameter (hydrodynamic diameter) was determined by cumulant analysis. <Non-volatile content (NV)> The non-volatile content of the aqueous dispersion in this disclosure was determined by weighing 1 g of the aqueous dispersion from the total mass of the aqueous dispersion, drying it in a hot air dryer at a temperature of 110°C for 1 hour, and considering the resulting residue as the non-volatile content. formula: [Non-volatile content (mass%) in aqueous resin dispersions] = ([Mass of residue] ÷ [1g of aqueous resin dispersion]) × 100

[0185] [Manufacturing Example 1] Core-shell emulsion 520 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser. A first-stage dropwise pre-emulsion was prepared in the dropping funnel, consisting of 163 parts of deionized water, 80 parts of a 25% aqueous solution of emulsifier [ADEKA Corporation, product name: Adekaryasorb SR-10], 322 parts of cyclohexyl methacrylate, 103 parts of 2-ethylhexyl acrylate, and 75 parts of 2-hydroxyethyl methacrylate. 74 parts of this pre-emulsion, representing 5% of the total monomer components, were added to the flask. The temperature was raised to 70°C while slowly blowing in nitrogen gas, and 30 parts of a 5% aqueous solution of ammonium persulfate were added to initiate polymerization. Subsequently, the remaining portion of the dropwise pre-emulsion was uniformly added dropwise to the flask over a period of 120 minutes.

[0186] After the dropwise dispensing was complete, the contents of the flask were maintained at 70°C for 60 minutes. Subsequently, a second-stage dropwise dispensing pre-emulsion consisting of 163 parts deionized water, 80 parts 25% aqueous solution of emulsifier [ADEKA Corporation, product name: Adeka Riasorb SR-10], 310 parts cyclohexyl methacrylate, 105 parts 2-ethylhexyl acrylate, 75 parts 2-hydroxyethyl methacrylate, and 10 parts 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine [ADEKA Corporation, product name: Adeka Stab LA-82], along with 30 parts 5% aqueous solution of ammonium persulfate, was uniformly added to the flask over 120 minutes.

[0187] After the dropwise addition was complete, the contents of the flask were maintained at 70°C for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization. After the resulting reaction solution was cooled to room temperature, an aqueous dispersion was prepared by filtering through a 300-mesh wire mesh. The obtained aqueous dispersion contained the polymer, which was a resin emulsion consisting of emulsion particles with a two-layer structure having an inner layer and an outer layer. The non-volatile content in this aqueous dispersion was 50%, the acid value derived from the carboxyl groups of the polymer was 0 mgKOH / g, the glass transition temperature of the inner layer resin constituting the resin emulsion particles contained in the emulsion was 32°C, and the glass transition temperature of the outer layer resin was also 32°C. The minimum film thickening temperature was 40°C, and the average particle size was 150 nm.

[0188] [Manufacturing Examples 2, 3, 6-8, 10-12, 14-18, Comparative Manufacturing Examples 1, 2] In Production Example 1, polymers were prepared in the same manner as in Production Example 1, except that polymerization was carried out using the monomer components shown in Tables 1 and 2, to obtain the polymers of Production Examples 2, 3, 6-8, 10-12, 14-18, and Comparative Production Examples 1 and 2.

[0189] [Manufacturing Example 4] Single Emulsion 536 parts of deionized water were placed in a flask equipped with a dropping funnel, stirrer, nitrogen gas inlet tube, thermometer, and reflux condenser. A first-stage dropping pre-emulsion was prepared in the dropping funnel, consisting of 326 parts of deionized water, 160 parts of a 25% aqueous solution of emulsifier [ADEKA Corporation, product name: Adeka Riasorb SR-10], 632 parts of cyclohexyl methacrylate, 208 parts of 2-ethylhexyl acrylate, 150 parts of 2-hydroxyethyl methacrylate, and 10 parts of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine [ADEKA Corporation, product name: Adeka Stab LA-87]. 74 parts of this pre-emulsion, representing 5% of the total amount of monomer components, were added to the flask. The mixture was then heated to 70°C while slowly blowing in nitrogen gas, and 30 parts of a 5% aqueous solution of ammonium persulfate were added to initiate polymerization. Subsequently, the remaining pre-emulsion for dropwise dispensing and 30 parts of a 5% ammonium persulfate aqueous solution were uniformly added dropwise to the flask over a period of 180 minutes.

[0190] After the dropwise addition was complete, the contents of the flask were maintained at 70°C for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization. After the resulting reaction solution was cooled to room temperature, the emulsion was prepared by filtering it through a 300-mesh wire mesh. The non-volatile content of this emulsion was 50%, the acid value derived from the carboxyl groups of the resin emulsion particles was 0 mgKOH / g, and the glass transition temperature of the resin constituting the resin emulsion particles contained in the emulsion was 32°C. The minimum film thickening temperature was 40°C, and the average particle size was 150 nm.

[0191] [Manufacturing examples 5, 9, 13] In Production Example 4, polymers were prepared in the same manner as in Production Example 4, except that polymerization was carried out using the monomer components shown in Tables 1 and 2, to obtain the polymers of Production Examples 5, 9, and 13.

[0192] The abbreviations listed in each table mean the following: IBOA: Isobornyl acrylate CHMA: Cyclohexyl methacrylate St: Styrene MMA: Methyl methacrylate 2EHA:2-Ethylhexylacrylate AA: Acrylic acid HEMA: Hydroxyethyl methacrylate LA-87:4-Methacryloyloxy-2,2,6,6-tetramethylpiperidine LA-82:4-Methacryloyloxy-1,2,2,6,6-Pentamethylpiperidine AC-10SL: Manufactured by Toagosei Co., Ltd., polyacrylic acid-based dispersant, Mw3000 Descoat N14: Manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Dispersant (Anionic surfactant, ammonium polycarboxylate salt (containing a phenyl group as a hydrophobic group and a carboxyl group as a hydrophilic group), Mw: 7000) BYK-190: Dispersant manufactured by BYChemie Japan Co., Ltd. (acid value 10 mg KOH / g) PG: Propylene glycol manufactured by ADEKA Corporation. CR-95: Manufactured by Ishihara Sangyo Co., Ltd., Titanium dioxide (rutile type) ST-200: Manufactured by Nippon Shokubai Co., Ltd., (meth)acrylic wax emulsion KF-6011: Polyether-modified silicone surfactant Aquacer531: Manufactured by Big Chemie Japan, a high-density oxidized polyethylene wax emulsion. BDG: Diethylene glycol monobutyl ether, manufactured by Nippon Emulsifier Co., Ltd. KF-6011: Manufactured by Shin-Etsu Chemical Co., Ltd., PEG-11 methyl ether dimethicone (polyether-modified silicone surfactant) PET: Manufactured by Futamura Chemical Co., Ltd., Product name: Taiko Polyester Film FE2001 OPP: Manufactured by Futamura Chemical Co., Ltd., Product name: FOR-AQ Crosslinking agent A: Oxazoline group-containing polymer (oxazoline group equivalent 220 g / mol, weight-average molecular weight 40,000, glass transition temperature 50°C) Crosslinking agent B: Polyisocyanate group-containing crosslinking agent (isocyanate group equivalent 255 g / mol, viscosity 2,000 mPa·s) Crosslinking agent C: Polycarbodiimide resin (carbodiimide group equivalent 430 g / mol, viscosity 100 mPa·s)

[0193] [Table 1]

[0194] [Table 2]

[0195] [Table 3]

[0196] [White Paste A] 411 parts deionized water, 67 parts dispersant [Jurimar AC-10SL, manufactured by Toagosei Co., Ltd.], 25 parts 25% aqueous ammonia, 60 parts propylene glycol, 1000 parts titanium dioxide [CR-95, manufactured by Ishihara Sangyo Co., Ltd.], and 200 parts glass beads (1 mm in diameter) are mixed in a disperser at a rotation speed of 3000 min⁻¹. -1 The solution was prepared by dispersing it for 120 minutes and then filtering it through a 300-mesh wire mesh. [White paste B, C] White pastes B and C were prepared in the same manner as white paste A, except that white paste A was prepared using the components shown in Table 3.

[0197] [Table 4]

[0198] [Example 1] To 19.8 parts of the emulsion obtained in Production Example 1, 2.8 parts of ST200 (manufactured by Nippon Shokubai) as a wax emulsion was added, and the mixture was heated in a homodisperser at a rotation speed of 1000 min⁻¹. -1 While stirring, 30 parts of white paste A, 20 parts of propylene glycol, 10 parts of diethylene glycol monobutyl ether (BDG, SP value 9.5), 0.4 parts of surfactant [Shin-Etsu Chemical Co., Ltd., KF-6011], and ion-exchanged water were added to make a total of 100 parts. After stirring for another 30 minutes, the mixture was filtered through a 3 μm filter [Advantec Co., Ltd., MCP-3-C10S] to prepare an aqueous ink.

[0199] [Examples 2-18, Comparative Examples 1 and 2] In Example 1, aqueous inks were prepared with the compositions shown in Tables 4 and 5 to obtain the aqueous inks of Examples 2-18 and Comparative Examples 1 and 2. <Inkjet printing> A water-based ink was used to fill a printing evaluation device (manufactured by Genesis Corporation) equipped with an inkjet print head (manufactured by Kyocera Corporation, part number: KJ4B-YH06WST-STDV) in air at a temperature of 25±1℃ and a relative humidity of 30±5%.

[0200] Next, in the print evaluation device, the head voltage was set to 26V, the frequency to 4kHz, the droplet output to 12pL (picoliters), the head temperature to 32°C, the resolution to 600dpi, and the negative pressure to -4.0kPa. Corona-treated polyester film [manufactured by Futamura Chemical Co., Ltd., product name: Taiko Polyester Film FE2001] was used as the recording medium, and the corona-treated polyester film was fixed to the transport table so that its longitudinal direction and transport direction were the same. A print command was transferred to the print evaluation device, and a solid image was printed on the corona-treated polyester film using an inkjet recording method with aqueous ink at a density of 100% (12pL, 600×600dpi). Immediately afterward, the corona-treated polyester film was dried in a 100°C dryer for 10 seconds to obtain a test sheet.

[0201] -Evaluation Method- <Scratch resistance> The printed image of the test sheet was rubbed with a nylon nonwoven fabric, and the adhesion to the substrate was evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Tables 4 and 5. [Evaluation Criteria] 5: Even when you rub the printed image, the image does not peel off at all. 4: If you rub the printed image, a very small amount of the image will peel off. 3: Rubbing the printed image will cause the image to peel off slightly. 2: If you rub the printed image, the image will peel off slightly. 1: When the printed image is rubbed, the image clearly peels off. 0: The printed image peels off easily when rubbed.

[0202] <Adhesion (PET)> The printed image on the test sheet was rubbed with a fingernail, and its adhesion to the substrate was evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Tables 4 and 5. [Evaluation Criteria] 5: Even when you rub the printed image with your fingernail, the image does not peel off at all. 4. If you rub the printed image with your fingernail, a very small amount of the image will peel off. 3: If you rub the printed image with your fingernail, the image will peel off slightly. 2: If you rub the printed image with your fingernail, the image will peel off slightly. 1: If you rub the printed image with your fingernail, the image will clearly peel off. 0: The printed image peels off easily when rubbed with a fingernail.

[0203] <Adhesion (OPP)> Except for changing the recording medium from corona-treated polyester film [Futamura Chemical Co., Ltd., product name: Taiko Polyester Film FE2001] to corona-treated OPP film [Futamura Chemical Co., Ltd., product name: FOR-AQ] to use as the test sheet, the evaluation was conducted under the same conditions as for adhesion (PET). The evaluation results for each example and comparative example are shown in Tables 4 and 5. <Blocking resistance> A polyester film that has not been corona-treated was placed on the printed surface of the test sheet, and 2 N / cm² of the polyester film was applied in air at 25°C. 2 After applying the load for one hour, the polyester film was quickly peeled off, and the resistance was observed. The blocking resistance was then evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Tables 4 and 5. [Evaluation Criteria] 5: There is absolutely no resistance when peeling off the polyester film. 4: There is only a very slight resistance when peeling off the polyester film. 3: You will feel a slight resistance when peeling off the polyester film. 2: Resistance is clearly felt when peeling off the polyester film. 1: Strong resistance is felt when peeling off the polyester film. 0: When peeling off the polyester film, there is a very strong resistance.

[0204] <Resistance to peeling off cellophane tape> Test sheets were prepared by changing the recording medium from corona-treated polyester film [Futamura Chemical Co., Ltd., product name: Taiko Polyester Film FE2001] to corona-treated OPP film [Futamura Chemical Co., Ltd., product name: FOR-AQ]. Adhesive tape (Nichiban Co., Ltd., Cellotape® No. 405, 24 mm wide) was applied to the obtained test sheets at room temperature and left to stand for 1 minute. After that, the tape was peeled off in a 180° direction and the resistance to peeling off the cellotape was evaluated based on the following evaluation criteria. The evaluation results for each example and comparative example are shown in Tables 4 and 5. [Evaluation Criteria] 5: The printed image does not peel off at all. 4. 1-20% of the printed image peels off. 3. 21-50% of the printed image peels off. 2: 51-75% of the printed image peels off. 1: 76-100% of the printed image peels off.

[0205] [Table 5]

[0206] [Table 6]

[0207] [Table 7] [Manufacturing Examples 19-22, 25, 26] Polymers were prepared in the same manner as in Production Example 1, except that polymerization was carried out using the monomer components shown in Table 8, to obtain the polymers of Production Examples 19-22, 25, and 26. [Manufacturing Examples 23, 24] In Production Example 4, polymers were prepared in the same manner as in Production Example 4, except that polymerization was carried out using the monomer components shown in Table 8, to obtain the polymers of Production Examples 23 and 24.

[0208] [Table 8] [Examples 19-26] In Example 1, aqueous inks were prepared with the compositions shown in Table 9 to obtain the aqueous inks of Examples 19-26. The results of evaluation using the evaluation method described above are shown in Table 9.

[0209] [Table 9]

Claims

1. An aqueous dispersion for aqueous ink for forming a printing layer on a resin film containing a polymer (A) having structural units derived from cyclic aliphatic group-containing monomers and a wax component (B), wherein the polymer (A) has a ratio of cyclic aliphatic group-containing monomers of 45 parts by mass or more and 95 parts by mass or less per 100 parts by mass of polymer (A), and the content ratio of structural units derived from other monomers of 5 parts by mass or more and 55 parts by mass or less per 100 parts by mass of polymer (A), Polymer (A) is an emulsion particle, The volume-average particle diameter of the polymer (A) is 100 nm or more and 300 nm or less. An aqueous dispersion in which the resin film is polyethylene terephthalate or an olefin-based resin.

2. The aqueous dispersion according to claim 1, wherein the volume average particle diameter of the aqueous dispersion is 100 nm or more and 300 nm or less.

3. The aqueous dispersion according to claim 1 or 2, wherein the acid value of the polymer (A) is 20 mg KOH / g or less.

4. The aqueous dispersion according to any one of claims 1 to 3, wherein the mass ratio of the polymer (A) and the wax component (B) is 99 / 1 to 80 / 20.

5. The aqueous dispersion according to any one of claims 1 to 4, wherein the polymer (A) is a polymer obtained by emulsion polymerization using an emulsifier, and the content of the reactive emulsifier per 100 parts by mass of monomer components constituting the polymer (A) is 3 parts by mass or more and 10 parts by mass or less.

6. An aqueous ink comprising an aqueous dispersion and a colorant according to any one of claims 1 to 5.

7. A water-based ink in which the coloring agent according to claim 6 is a white pigment.

8. A water-based ink comprising one colorant selected from yellow, magenta, cyan, black, red, blue, and green, as described in claim 6.

9. A printed article comprising a printed layer formed from an aqueous ink according to any one of claims 6 to 8.

10. A method for producing an aqueous dispersion for aqueous inks for forming a printing layer on a resin film containing a polymer (A) having structural units derived from a cyclic aliphatic group-containing monomer and a wax component (B), The polymer (A) is such that the proportion of cyclic aliphatic group-containing monomers per 100 parts by mass of the polymer (A) is 45 parts by mass or more and 95 parts by mass or less, and the proportion of structural units derived from other monomers per 100 parts by mass of the polymer (A) is 5 parts by mass or more and 55 parts by mass or less. The polymer (A) is a polymer obtained by emulsion polymerization using an emulsifier, wherein the amount of reactive emulsifier per 100 parts by mass of monomer components constituting polymer (A) is 3 parts by mass or more and 10 parts by mass or less. The volume-average particle diameter of the polymer (A) is 100 nm or more and 300 nm or less. A method for producing an aqueous dispersion in which the resin film is polyethylene terephthalate or an olefin-based resin.

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