Ink for Inkjet

Abstract

To provide inkjet ink which is excellent in discharge stability, and blocking resistance when an image is formed.SOLUTION: Inkjet ink contains a nonionic water soluble polymer compound containing an amide bond, resin emulsion particles, and water. The nonionic water soluble polymer compound containing the amide bond is preferably polyvinyl pyrrolidone. A weight average molecular weight of the nonionic water soluble polymer compound containing the amide bond is preferably 5,000-500,000.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink for inkjet printing.

Background Art

[0002] In a recording method in which ink is ejected from the nozzles of a printer head and directly sprayed onto a printing medium for printing, the ink used is required to have functions such as stable ejection, image uniformity, and adhesion to the printing medium. Further, since the printed medium is wound around a roll, it is also necessary to suppress blocking. In recent years, due to environmental considerations, an ink composition for aqueous ink having the above functions has been demanded. In addition, as non-printing media, printing on recording media for commercial printing using films of non-absorbent resins such as coated paper, polyester films such as polyethylene terephthalate (PET), polyvinyl chloride films, polypropylene films such as biaxially stretched polypropylene films (OPP), polyethylene films, and nylon films has been demanded.

[0003] Patent Document 1 discloses an acrylic resin emulsion for aqueous inkjet ink containing acrylic resin particles having an acid value of 1 to 100 mgKOH / g, 1 and an acrylic resin emulsion for aqueous inkjet ink characterized in that the ratio (As / At) of the molar ratio (As) of the acidic group-containing monomer in the surface region of the acrylic resin particles measured with an H spin diffusion time of 5 ms to the molar ratio (At) of the acidic group-containing monomer in the entire acrylic resin particles is 9 or more, and an aqueous inkjet ink composition containing the emulsion are described.

[0004] Even better ones have been demanded for the ejection stability of the above ink and the blocking resistance when forming an image.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent Application Laid-Open No. 2014-141672 Summary of the Invention Problems to be Solved by the Invention

[0006] Accordingly, an object of the present invention is to provide an inkjet ink having excellent ejection stability (image uniformity) and blocking resistance when forming an image. Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventor has found that an inkjet ink containing a specific water-soluble polymer compound, resin emulsion particles, and water is suitable for aqueous inks and can solve the above problems, and has completed the present invention.

[0008] That is, the inkjet ink of the present invention contains a nonionic water-soluble polymer compound containing an amide bond, resin emulsion particles, and water. The nonionic water-soluble polymer compound containing the amide bond is preferably polyvinylpyrrolidone. The weight average molecular weight of the nonionic water-soluble polymer compound containing the amide bond is preferably 5,000 to 500,000. The content of the nonionic water-soluble polymer compound containing the amide bond is preferably 0.05 to 10% by mass. The resin emulsion particles preferably contain a (meth)acrylic polymer. The acid value derived from the carboxyl group of the resin emulsion particles is preferably 0 to 6 mgKOH / g. Effects of the Invention

[0009] According to the inkjet ink of the present invention, it is possible to provide an inkjet ink having excellent ejection stability and blocking resistance when forming an image. Modes for Carrying Out the Invention

[0010] 1. Ink for Inkjet The ink for inkjet of the present invention contains a nonionic water-soluble polymer compound containing an amide bond, resin emulsion particles (resin particles), and water.

[0011] 1-1 Nonionic water-soluble polymer compound containing an amide bond The ink for inkjet of the present invention contains a nonionic water-soluble polymer compound containing an amide bond. Examples of the nonionic water-soluble polymer compound containing an amide bond include polyvinylpyrrolidone, polyacrylamide, etc., and polyvinylpyrrolidone is particularly preferable.

[0012] The weight average molecular weight of the nonionic water-soluble polymer compound containing an amide bond is preferably 5,000 to 500,000, more preferably 10,000 to 200,000. The above weight average molecular weight means the weight average molecular weight (converted to PEO) measured using gel permeation chromatography [manufactured by Tosoh Corporation, product number: HLC-8320GPC, column: Shodex KD-806M, carrier solution: DMF].

[0013] The content of the nonionic water-soluble polymer compound containing an amide bond is preferably 0.05 to 10% by mass, more preferably 0.1 to 2% by mass. By containing a nonionic water-soluble polymer compound containing an amide bond, the ink for inkjet of the present invention has excellent ejection stability and excellent blocking resistance when an image is formed.

[0014] 1-2 Resin emulsion particles The resin emulsion particles contained in the ink for inkjet of the present invention may preferably contain structural units derived from monofunctional monomers and / or polyfunctional monomers. The structural units derived from monofunctional monomers and polyfunctional monomers are obtained by polymerizing monomers containing monofunctional monomers and polyfunctional monomers. The above-mentioned monofunctional monomers and polyfunctional monomers may be used alone or in combination.

[0015] Examples of the monofunctional monomer include ethylenically unsaturated double bond-containing monomers, but are not limited to such examples. These monomers may be used alone or in combination of two or more.

[0016] In the present specification, “(meth)acrylate” means “acrylate” or “methacrylate”, and “(meth)acrylic” means “acrylic” or “methacrylic”.

[0017] Examples of the ethylenically unsaturated double bond-containing monomers include acid group-containing monomers, alkyl (meth)acrylates, hydroxyl group-containing (meth)acrylates, piperidine group-containing monomers, 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. These ethylenically unsaturated double bond-containing monomers may be used alone or in combination of two or more.

[0018] Examples of the acid group-containing monomer include carboxyl group-containing aliphatic monomers such as (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, and vinylbenzoic acid. However, the present invention is not limited to such examples only. These acid group-containing monomers may be used alone or in combination of two or more. Among these acid group-containing monomers, acrylic acid, methacrylic acid, and itaconic acid are preferable, and acrylic acid and methacrylic acid are more preferable, from the viewpoint of improving the dispersion stability of the resin emulsion particles.

[0019] Examples of the alkyl (meth)acrylate include alkyl (meth)acrylates having 1 to 18 carbon atoms in the ester group such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, tridecyl (meth)acrylate, cyclohexyl (meth)acrylate, n-lauryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate. However, the present invention is not limited to such examples only. These alkyl (meth)acrylates may be used alone or in combination of two or more.

[0020] Examples of the hydroxyl group-containing (meth)acrylate include, but are not limited to, hydroxyl group-containing (meth)acrylates having 1 to 18 carbon atoms in the ester group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. These hydroxyl group-containing (meth)acrylates may be used alone or in combination of two or more thereof.

[0021] Examples of the piperidine group-containing monomer include, but are not limited to, 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, 4-crotonoylamino-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, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine. These piperidine group-containing monomers may be used alone or in combination of two or more thereof.

[0022] Examples of the oxo group-containing monomer include, but are not limited to only such examples, (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 alone or in combination of two or more.

[0023] Examples of the fluorine atom-containing monomer include, but are not limited to only such examples, fluorine atom-containing alkyl (meth)acrylates having 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 alone or in combination of two or more.

[0024] Examples of the nitrogen atom-containing monomer include, but are not limited to only such examples, acrylamide compounds such as (meth)acrylamide, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl acrylamide, and diacetone acrylamide; nitrogen atom-containing (meth)acrylate compounds such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate; N-vinylpyrrolidone; (meth)acrylonitrile; etc. These nitrogen atom-containing monomers may be used alone or in combination of two or more.

[0025] Examples of the epoxy group-containing monomer 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 alone or in combination of two or more.

[0026] Examples of the alkoxyalkyl (meth)acrylate include, but are not limited to, methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, and trimethylolpropane tripropoxy (meth)acrylate. These alkoxyalkyl (meth)acrylates may be used alone or in combination of two or more.

[0027] Examples of the silane group-containing monomer 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 alone or in combination of two or more.

[0028] Examples of the carbonyl group-containing monomer include, but are not limited to, acrolein, humulstyrene, vinyl ethyl ketone, (meth)acryloyloxyalkyl propenal, acetonyl (meth)acrylate, diacetone (meth)acrylate, 2-hydroxypropyl (meth)acrylate acetylacetate, butanediol-1,4-acrylate acetylacetate, and 2-(acetoacetoxy)ethyl (meth)acrylate. These carbonyl group-containing monomers may be used alone or in combination of two or more.

[0029] Examples of the aziridinyl group-containing monomer include, but are not limited to, (meth)acryloyl aziridine, 2-aziridinylethyl (meth)acrylate, etc. These aziridinyl group-containing monomers may be used alone or in combination of two or more.

[0030] Examples of the styrene monomer include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, vinyltoluene, etc. These styrene monomers may be used alone or in combination of two or more. The styrene monomer may have a functional group such as an alkyl group such as a methyl group or a tert-butyl group, a nitro group, a nitrile group, an alkoxyl group, an acyl group, a sulfone group, a hydroxyl group, or a halogen atom on the benzene ring. Among the styrene monomers, styrene is preferred from the viewpoint of enhancing water resistance.

[0031] Examples of the aralkyl (meth)acrylate 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, naphthylmethyl (meth)acrylate, etc. These aralkyl (meth)acrylates may be used alone or in combination of two or more.

[0032] Examples of the addition-polymerizable oxazoline 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, 2-isopropenyl-5-ethyl-2-oxazoline, etc. These addition-polymerizable oxazolines may be used alone or in combination of two or more. Among these addition-polymerizable oxazolines, 2-isopropenyl-2-oxazoline is preferred because it is easily available.

[0033] Examples of suitable monofunctional monomers include, for example, alkyl (meth)acrylate, hydroxyl group-containing (meth)acrylate, piperidine group-containing monomer, oxo group-containing monomer, fluorine atom-containing monomer, nitrogen atom-containing monomer, epoxy group-containing monomer, styrene-based monomer, etc. These monomers may be used alone or in combination of two or more. Among the monofunctional monomers, from the viewpoint of further improving the adhesion (scratch resistance) to corona-treated PET, OPP, etc., piperidine group-containing monomers, nitrogen atom-containing monomers, and addition-polymerizable oxazolines are preferred. Among them, 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. In addition, from the viewpoint that when a hydroxyl group-containing (meth)acrylate is included as a monofunctional monomer, emulsion particles without coarse particles are easily obtained and the discharge stability of the ink containing the emulsion particles is excellent, it is preferable to include a hydroxyl group-containing (meth)acrylate.

[0034] The content rates of the piperidine group-containing monomer, addition-polymerizable oxazoline, and hydroxyl group-containing (meth)acrylate in the monomer component are preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.5% by mass or more, from the viewpoint of further improving weather resistance and adhesion, and preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, from the viewpoint of improving water resistance. The content rates of the piperidine group-containing monomer, addition-polymerizable oxazoline, and hydroxyl group-containing (meth)acrylate in the monomer component are more preferably 0.1 to 30% by mass, still more preferably 0.2 to 20% by mass, and even more preferably 0.5 to 10% by mass, respectively.

[0035] When the resin emulsion particles are formed in multiple layers, the piperidine group-containing monomer, and / or addition-polymerizable oxazoline, and / or hydroxyl group-containing (meth)acrylate may be contained in the monomer component constituting any layer, but from the viewpoint of further improving adhesion, it is preferably contained in the monomer component constituting at least the outermost layer. Therefore, it is preferable that the monomer component contains a piperidine group-containing monomer, and / or addition-polymerizable oxazoline, and / or hydroxyl group-containing (meth)acrylate. When the resin emulsion particles are formed in multiple layers, it is preferable that the monomer component constituting at least the outermost layer contains a piperidine group-containing monomer, and / or addition-polymerizable oxazoline, and / or hydroxyl group-containing (meth)acrylate. The content rates of the piperidine group-containing monomer, addition-polymerizable oxazoline, and hydroxyl group-containing (meth)acrylate in the monomer component are more preferably 0.1 to 30% by mass, still more preferably 0.2 to 20% by mass, and even more preferably 0.5 to 10% by mass, respectively.

[0036] Examples of polyfunctional monomers include di(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms such as 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; alkyldi(meth)acrylates having 2 to 50 moles of added alkylene oxide groups of 2 to 4 carbon atoms such as polyethylene glycol di(meth)acrylate with 2 to 50 moles of added ethylene oxide, polypropylene glycol di(meth)acrylate with 2 to 50 moles of added propylene oxide, and tripropylene glycol di(meth)acrylate; tri(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms such as ethoxylated glycerol tri(meth)acrylate, propylene oxide-modified glycerol tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol monohydroxy tri(meth)acrylate, and trimethylolpropane triethoxytri(meth)acrylate; tetra(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms such as pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate; penta(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms such as pentaerythritol penta(meth)acrylate and dipentaerythritol (monohydroxy)penta(meth)acrylate; hexa(meth)acrylates of polyhydric alcohols having 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 polyfunctional (meth)acrylates such as urethane (meth)acrylate, but are not limited to such examples. These polyfunctional monomers may each be used alone or in combination of two or more.;

[0037] Among the polyfunctional monomers, from the viewpoint of achieving both blocking resistance and adhesion, alkyldi(meth)acrylates having 4 to 8 carbon atoms in the alkyl group having two hydroxyl groups, polyethylene glycol di(meth)acrylates having an addition mole number of ethylene oxide of 2 to 50, polypropylene glycol di(meth)acrylates having an addition mole number of propylene oxide of 2 to 50, tri(meth)acrylates of polyhydric alcohols, tetra(meth)acrylates of polyhydric alcohols, penta(meth)acrylates of polyhydric alcohols, and hexa(meth)acrylates of polyhydric alcohols are preferable, and ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylates having an addition mole number of ethylene oxide of 2 to 50, 1,4-butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate are more preferable.

[0038] The resin emulsion particles preferably contain a (meth)acrylic polymer, and more preferably contain a structural unit derived from styrene.

[0039] (Structural unit derived from ultraviolet absorber monomer) Further, from the viewpoint of imparting ultraviolet absorption to the resin emulsion particles, an ultraviolet absorber monomer may be contained in the monomer component within a range that does not inhibit the object of the present invention.

[0040] Examples of the ultraviolet absorber monomer include benzotriazole-based ultraviolet absorber monomers, benzophenone-based ultraviolet absorber monomers, etc., but are not limited to such examples. These ultraviolet absorber monomers may each be used alone or in combination of two or more.

[0041] Examples of benzotriazole-based ultraviolet-absorbing monomers include, for example, 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, 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)acryloyloxyethylphenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(meth)acryloyloxyethylphenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(β-(meth)acryloyloxyethoxy)-3'-tert-butylphenyl]-4-tert-butyl-2H-benzotriazole, etc., but are not limited to such examples. These benzotriazole-based ultraviolet-absorbing monomers may be used alone or in combination of two or more.

[0042] Examples of benzophenone-based ultraviolet-absorbing monomers include, but are not limited to, 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, 2-hydroxy-3-tert-butyl-4-[2-(meth)acryloyloxy]butoxybenzophenone, etc. These benzophenone-based ultraviolet-absorbing monomers may be used alone or in combination of two or more kinds.

[0043] (Crosslinking agent) By further containing a crosslinking agent in the resin emulsion particles, crosslinkability can be imparted. The crosslinking agent may be one that initiates a crosslinking reaction at room temperature or one that initiates a crosslinking reaction by heat. In the ink for inkjet of the present invention, by containing a crosslinking agent in the resin emulsion particles, the blocking resistance and adhesion can be further improved.

[0044] Suitable crosslinking agents include, for example, oxazoline group-containing compounds, isocyanate group-containing compounds, aminoplast resins, etc. These crosslinking agents may be used alone or in combination of two or more kinds. Among these crosslinking agents, from the viewpoint of improving the storage stability of the ink for inkjet of the present invention, oxazoline group-containing compounds are preferred.

[0045] An oxazoline group-containing compound is a compound having two or more oxazoline groups in the molecule. Examples of the oxazoline group-containing compound include, but are not limited to, 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), 2,2'-octamethylene-bis(2-oxazoline), 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, an oxazoline ring-containing polymer, etc. These oxazoline group-containing compounds may be used alone or in combination of two or more. Among the oxazoline group-containing compounds, from the viewpoint of improving reactivity, a water-soluble oxazoline group-containing compound is preferable, and a water-soluble oxazoline ring-containing polymer is more preferable.

[0046] The oxazoline ring-containing polymer can be easily prepared by polymerizing a monomer component containing an addition-polymerizable oxazoline as an essential component and, if necessary, a monomer copolymerizable with the addition-polymerizable oxazoline.

[0047] As the addition-polymerizable oxazoline, those similar to the examples given in the section on ethylenically unsaturated double bond-containing monomers can be preferably employed.

[0048] Oxazoline group-containing compounds can be easily obtained commercially, for example, as Epocros WS-500, Epocros WS-700, Epocros K-2010, Epocros K-2020, Epocros K-2030, etc. manufactured by Nippon Shokubai Co., Ltd. Among these, from the viewpoint of improving reactivity, water-soluble oxazoline group-containing compounds such as Epocros WS-500 and Epocros WS-700 manufactured by Nippon Shokubai Co., Ltd. are preferred.

[0049] The isocyanate group-containing compound is a compound containing an isocyanate group that can react with a hydroxyl group possessed by a hydroxyl group-containing monomer used as a monomer component.

[0050] Examples of the isocyanate group-containing compound include water-dispersed (block) polyisocyanate. Note that (block) polyisocyanate means polyisocyanate and / or blocked polyisocyanate.

[0051] Examples of the water-dispersed polyisocyanate include those obtained by dispersing a polyisocyanate imparted with hydrophilicity by a polyethylene oxide chain in water with an anionic dispersant or a nonionic dispersant.

[0052] Examples of the polyisocyanate include diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate; derivatives (modified products) of polyisocyanates such as trimethylolpropane adducts, biuret bodies, and isocyanurate bodies of these diisocyanates, but are not limited to such examples. These polyisocyanates may be used alone or in combination of two or more.

[0053] Water-dispersible polyisocyanates are commercially readily available, for example, under the trade names Aquanate 100, Aquanate 110, Aquanate 200, Aquanate 210, etc. manufactured by Nippon Polyurethane Industry Co., Ltd.; Bayhydur TPLS-2032, SUB-Isocyanate L801, etc. manufactured by Sumika Bayer Urethane Co., Ltd.; Takenate WD-720, Takenate WD-725, Takenate WD-220, etc. manufactured by Mitsui Takeda Chemicals, Inc.; Resamin D-56, etc. manufactured by Dainichi Seika Kogyo Co., Ltd.

[0054] Water-dispersible blocked polyisocyanates are those obtained by blocking the isocyanate groups of water-dispersible polyisocyanates with a blocking agent. Examples of the blocking agent include, but are not limited to, diethyl malonate, ethyl acetoacetate, ε-caprolactam, butanone oxime, cyclohexanone oxime, 1,2,4-triazole, dimethyl-1,2,4-triazole, 3,5-dimethylpyrazole, imidazole, etc. These blocking agents may be used alone or in combination of two or more. Among these blocking agents, those that cleave at a temperature of 160°C or lower, preferably 150°C or lower, are desirable. Examples of suitable blocking agents include butanone oxime, cyclohexanone oxime, 3,5-dimethylpyrazole, etc. Among these, butanone oxime is more preferable.

[0055] Water-dispersible blocked polyisocyanates are commercially readily available, for example, under the trade names Takenate WB-720, Takenate WB-730, Takenate WB-920, etc. manufactured by Mitsui Takeda Chemicals, Inc.; Bayhydur BL116, Bayhydur BL5140, Bayhydur BL5235, Bayhydur TPLS2186, Desmodur VPLS2310, etc. manufactured by Sumika Bayer Urethane Co., Ltd.

[0056] Amino plastic resins are addition condensates of compounds having amino groups such as melamine and guanamine with formaldehyde, and are also called amino resins.

[0057] Examples of aminoplast resins include melamine resins such as dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine, fully alkylated methylated melamine, fully alkylated butylated melamine, fully alkylated isobutylated melamine, fully alkylated mixed etherified melamine, methylol group type methylated melamine, imino group type methylated melamine, methylol group type mixed etherified melamine, imino group type mixed etherified melamine, etc.; guanamine resins such as butylated benzoguanamine, methyl / ethyl mixed alkylated benzoguanamine, methyl / butyl mixed alkylated benzoguanamine, butylated glycoluril, etc., but are not limited to such examples. These aminoplast resins may be used alone or in combination of two or more.

[0058] Aminoplast resins can be easily obtained commercially, for example, under the trade names Mycote 506, Mycote 1128, Cymel 232, Cymel 235, Cymel 254, Cymel 303, Cymel 325, Cymel 370, Cymel 771, Cymel 1170, etc. manufactured by Mitsui Cytec Co., Ltd.

[0059] The amount of aminoplast resin is usually preferably adjusted so that the mass ratio of the solid content of the polymer component contained in the resin emulsion particles to the solid content of the aminoplast resin [solid content of polymer component / solid content of aminoplast resin] is 60 / 40 to 99 / 1. Among the above crosslinking agents, addition-polymerizable oxazoline is preferred from the viewpoint of further improving the adhesion to corona-treated PET, OPP, etc.

[0060] In the present invention, in addition to the above-mentioned crosslinking agents, crosslinking agents such as carbodiimide compounds; polyvalent metal compounds represented by zirconium compounds, zinc compounds, titanium compounds, aluminum compounds, etc. can be used within the range not inhibiting the object of the present invention.

[0061] Acid value derived from carboxyl groups of 1-2-1 resin emulsion particles The acid value derived from carboxyl groups of resin emulsion particles contained in the ink for inkjet of the present invention is preferably 0 to 6, and can be adjusted by adjusting the composition of monomers used for polymerization of the resin emulsion particles.

[0062] The acid value derived from carboxyl groups of resin emulsion particles is the number of milligrams of potassium hydroxide required to neutralize carboxyl groups present in 1 g of resin emulsion particles. When the polymerization component contained in the resin emulsion particles is an ethylenically unsaturated double bond-containing monomer and the resin emulsion particles do not contain other carboxyl groups, it is possible to approximate, as the acid value, the number of milligrams of potassium hydroxide required to neutralize carboxyl groups present in 1 g of the ethylenically unsaturated double bond-containing monomer component. In the present specification, the acid value derived from carboxyl groups of the above resin emulsion particles is a value that does not include acid values derived from acid groups other than carboxyl groups in the emulsifier and initiator. The above acid value is preferably 0 to 5, more preferably 0 to 4, still more preferably 0 to 1, and particularly preferably 0. By lowering the acid value derived from carboxyl groups of resin emulsion particles, the image uniformity when made into an ink can be made more excellent.

[0063] 1-2-2 Glass transition temperature The above resin emulsion particles preferably contain a polymer component having a glass transition temperature of 55°C or higher and a polymer component having a glass transition temperature of less than 55°C. The glass transition temperature of the polymer component can be adjusted by adjusting the composition of monomers used for the monomer component.

[0064] In the present specification, the glass transition temperature (Tg) of the polymer component is calculated using the glass transition temperature of the homopolymer of the monomer used for the monomer component constituting the polymer component, by the formula: 1 / Tg = Σ(Wm / Tgm) / 100 [In the formula, Wm represents the content ratio (% by mass) of monomer m in the monomer components constituting the polymer component, and Tgm represents the glass transition temperature (absolute temperature: K) of the homopolymer of monomer m.] It means the temperature determined based on the Fox's equation represented by .

[0065] The glass transition temperature of the polymer component is, for example, 95 °C for the homopolymer of acrylic acid, 130 °C for the homopolymer of methacrylic acid, 105 °C for the homopolymer of methyl methacrylate, 100 °C for the homopolymer of styrene, 83 °C for the homopolymer of cyclohexyl methacrylate, 20 °C for the homopolymer of n-butyl methacrylate, -70 °C for the homopolymer of 2-ethylhexyl acrylate, -56 °C for the homopolymer of n-butyl acrylate, 55 °C for the homopolymer of hydroxyethyl methacrylate, 165 °C for the homopolymer of acrylamide, 130 °C for the monomer of 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 130 °C for the homopolymer of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, 100 °C for the homopolymer of 2-[2'-hydroxy-5'-methacryloyloxyethylphenyl]-2H-benzotriazole, and 100 °C for the homopolymer of 2-isopropenyl-2-oxazoline.

[0066] The glass transition temperature of the polymer component is a value determined based on the above Fox's equation, and preferably, the measured value of the glass transition temperature of the polymer component is the same as the value determined based on the above Fox's equation. The measured value of the glass transition temperature of the polymer component can be determined, for example, by measuring its differential scanning calorimetry.

[0067] In this specification, unless otherwise specified, the glass transition temperature of the polymer component means the glass transition temperature determined based on the above formula. For monomers with an unknown glass transition temperature, such as special monomers and polyfunctional monomers, when the total amount of monomers with an unknown glass transition temperature in the monomer component is 10% by mass or less, the glass transition temperature is determined using only the monomers with a known glass transition temperature. When the total amount of monomers with an unknown glass transition temperature in the monomer component exceeds 10% by mass, the glass transition temperature of the (meth)acrylic pressure-sensitive adhesive resin is determined by differential scanning calorimetry (DSC), differential thermal analysis (DTA), thermomechanical analysis (TMA), etc.

[0068] Examples of the differential scanning calorimetry measurement device include, for example, the product number: DSC220C manufactured by Seiko Instruments Inc. Also, when measuring the differential scanning calorimetry, there are no particular limitations on the method of drawing the differential scanning calorimetry (DSC) curve, the method of obtaining the first derivative curve from the differential scanning calorimetry (DSC) curve, the method of performing smoothing processing, the method of obtaining the target peak temperature, etc. For example, when using the above measurement device, it may be plotted from the data obtained by using the measurement device. At that time, analytical software capable of performing mathematical processing can be used. Examples of the analytical software include, for example, analytical software [manufactured by Seiko Instruments Inc., product number: EXSTAR6000], but it is not limited to such examples only. Note that the peak temperature obtained in this way may include an error of about ±5°C due to plotting.

[0069] The above resin emulsion particles may be core-shell resin emulsion particles in which a polymer component having a glass transition temperature of 55°C or higher and a polymer component having a glass transition temperature of less than 55°C are laminated, or may be emulsion particles in which a polymer component having a glass transition temperature of 55°C or higher and a polymer component having a glass transition temperature of less than 55°C are uniformly mixed, or may be a mixture of resin emulsion particles composed of a polymer component having a glass transition temperature of 55°C or higher and resin emulsion particles composed of a polymer component having a glass transition temperature of less than 55°C. As the core-shell resin emulsion particles, the core portion may be composed of a polymer component having a glass transition temperature of 55°C or higher and the shell portion may be composed of a polymer component having a glass transition temperature of less than 55°C, or vice versa. By the resin emulsion particles containing a polymer component having a glass transition temperature of 55°C or higher and a polymer component having a glass transition temperature of less than 55°C, it is possible to achieve both adhesion to the substrate and blocking resistance.

[0070] As the structure of the emulsion particles, as long as it contains a polymer component having a glass transition temperature of 55°C or higher and a polymer component having a glass transition temperature of less than 55°C, for example, it may be a substantially uniform mixed composition, but a multilayer structure is preferred. Specifically, the multilayer structure refers to a core-shell structure composed of the outermost shell portion and the core portion inside it. The core portion may have a substantially uniform composition or may have a multilayer structure (further core-shell). It is preferred that the core portion has a substantially uniform composition.

[0071] The content ratio of the polymer component having a glass transition temperature of 55°C or higher and the polymer component having a glass transition temperature of less than 55°C is preferably 1:99 to 70:30, more preferably 1:99 to 40:60, and particularly preferably 1:99 to 30:70 in terms of mass ratio. When the resin emulsion particles contain two or more types of polymer components, the average glass transition temperature is preferably 0 to 30°C.

[0072] As the resin emulsion particles contained in the ink for inkjet of the present invention, among others, core-shell resin emulsion particles in which the core part contains a polymer component having a glass transition temperature of 55°C or higher and the shell part contains a polymer component having a glass transition temperature of less than 55°C are preferable. Here, when the above emulsion particles are composed of a shell part on the outermost layer and a core part having a substantially uniform composition, the "glass transition temperature of the shell part" and the "glass transition temperature of the core part" are literal meanings. When the "core part" is composed of multiple layers, the "glass transition temperature of the shell part" means the glass transition temperature of the outermost layer, and the "glass transition temperature of the core part" means the average glass transition temperature of the core part composed of multiple layers.

[0073] The glass transition temperature of the polymer component of the core part is preferably 60°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, particularly preferably 90°C or higher, and most preferably 95°C or higher. Also, as the upper limit of the glass transition temperature of the polymer component of the above core part, from the viewpoint of blocking resistance, the higher the better, but if it is too high, film formation failure may occur, and 300°C or lower is preferable, and 200°C or lower is more preferable.

[0074] The glass transition temperature of the polymer component of the shell part is preferably 40°C or lower, more preferably 30°C or lower, still more preferably 25°C or lower, even more preferably 20°C or lower, particularly preferably 15°C or lower, and most preferably 10°C or lower. Also, as the lower limit of the glass transition temperature of the polymer component of the above shell part, -70°C or higher is preferable, -50°C or higher is more preferable, -30°C or higher is still more preferable, and -20°C or higher is particularly preferable.

[0075] As the combination of the glass transition temperature of the polymer component of the above core part and the polymer component of the above shell part: Preferably, the glass transition temperature of the polymer component in the core part is 55 °C or higher (more preferably, the glass transition temperature of the polymer component in the core part is 200 °C or lower), and the glass transition temperature of the polymer component in the shell part is 25 °C or lower (more preferably, the glass transition temperature of the polymer component in the shell part is -20 °C or higher); More preferably, the glass transition temperature of the polymer component in the core part is 90 °C or higher (more preferably, the glass transition temperature of the polymer component in the core part is 200 °C or lower), and the glass transition temperature of the polymer component in the shell part is less than 55 °C (more preferably, the glass transition temperature of the polymer component in the shell part is -20 °C or higher); Even more preferably, the glass transition temperature of the polymer component in the core part is 90 °C or higher (more preferably, the glass transition temperature of the polymer component in the core part is 200 °C or lower), and the glass transition temperature of the polymer component in the shell part is 25 °C or lower (more preferably, the glass transition temperature of the polymer component in the shell part is -20 °C or higher).

[0076] The above shell part preferably contains a piperidine group-containing monomer, and / or an addition-polymerizable oxazoline, and / or a hydroxyl group-containing (meth)acrylate. The content of the piperidine group-containing monomer, addition-polymerizable oxazoline, and hydroxyl group-containing (meth)acrylate in the shell part is preferably 0.1 to 30% by mass, more preferably 0.2 to 20% by mass, and even more preferably 0.5 to 10% by mass, respectively, based on 100% by mass of the total amount of monomers constituting the shell part. The above core part preferably contains a styrene-based monomer. The content of the styrene-based monomer in the above core part is preferably 1 to 70% by mass based on 100% by mass of the total amount of monomers constituting the core part.

[0077] 1-2-3 Other properties (Weight average molecular weight) In the ink for inkjet of the present invention, the weight average molecular weight of the polymer component constituting the resin emulsion particles is preferably 100,000 or more, more preferably 300,000 or more, still more preferably 550,000 or more, and particularly preferably 600,000 or more, from the viewpoint of further improving water resistance and adhesion. The upper limit value of the weight average molecular weight of the polymer component is preferably 5,000,000 or less from the viewpoint of improving film-forming properties and water resistance.

[0078] In addition, in this specification, the weight average molecular weight of the polymer component constituting the resin emulsion particles means the weight average molecular weight (polystyrene conversion) measured using gel permeation chromatography [manufactured by Tosoh Corporation, product number: HLC-8120GPC, columns: TSKgel G-5000HXL and TSKgel GMHXL-L used in series].

[0079] (Volume average particle diameter) The volume average particle diameter of the resin emulsion particles contained in the ink for inkjet of the present invention is preferably 30 nm or more, more preferably 50 nm or more, from the viewpoint of improving the image uniformity of the resin emulsion particles, and is preferably 350 nm or less, more preferably 300 nm or less, from the viewpoint of further improving storage stability and water resistance.

[0080] In addition, in this specification, the volume average particle diameter of the resin emulsion particles means the volume average particle diameter measured using a particle size distribution measuring instrument by the dynamic light scattering method [manufactured by Particle Sizing Systems, product name: NICOMP Model 380].

[0081] 1-2-4 Method for producing resin emulsion particles The ink for inkjet of the present invention preferably contains an emulsion containing resin emulsion particles which are polymer components obtained by emulsion polymerization of the above-described monomer components. As a method for producing the resin emulsion particles contained in the ink for inkjet of the present invention, it is preferable to carry out emulsion polymerization of the above-described monomer components in the presence of an emulsifier.

[0082] Examples of the method for emulsion polymerizing the monomer components include, for example, a method of dissolving an emulsifier in an aqueous medium containing a water-soluble organic solvent such as a lower alcohol such as methanol and water, and dropping the monomer components and a polymerization initiator under stirring, and a method of dropping a monomer component preliminarily emulsified using an emulsifier and water into water or an aqueous medium. However, the method is not limited to such methods. The amount of the medium may be appropriately set in consideration of the non-volatile content contained in the obtained emulsion. The medium may be charged into the reaction vessel in advance, or may be used as a pre-emulsion. Further, the medium may be used when necessary for emulsion polymerizing the monomer components to produce an emulsion.

[0083] When emulsion polymerizing the monomer components, emulsion polymerization may be carried out after mixing the monomer components, the emulsifier, and the medium, or the monomer components, the emulsifier, and the medium may be emulsified by stirring to prepare a pre-emulsion, and then emulsion polymerization may be carried out. Alternatively, emulsion polymerization may be carried out by mixing at least one of the monomer components, the emulsifier, and the medium with the pre-emulsion of the remainder. The monomer components, the emulsifier, and the medium may be added all at once, added in portions, or continuously dropped.

[0084] When forming an outer layer on the resin emulsion particles contained in the emulsion obtained above, which consists of a polymer component for the outer layer (shell), the outer layer can be formed on the resin emulsion particles by emulsion-polymerizing the monomer component in the above emulsion in the same manner as above. Further, when forming an additional outer layer on the resin emulsion particles having the above outer layer (intermediate layer), the outer layer consisting of another polymer component for the outer layer can be formed on the resin emulsion particles by emulsion-polymerizing the monomer component in the emulsion in the same manner as above. In this way, resin emulsion particles having a multilayer structure (core-shell resin emulsion particles) can be prepared by the multi-stage emulsion polymerization method.

[0085] Note that when preparing core-shell resin emulsion particles, one or more stages of emulsion polymerization may be carried out before performing the emulsion polymerization for forming the inner layer (core) consisting of the polymer component for the inner layer first, and one or more stages of emulsion polymerization may be carried out between the emulsion polymerization for forming the inner layer and the emulsion polymerization for forming the intermediate layer. Also, one or more stages of emulsion polymerization may be carried out between the emulsion polymerization for forming the intermediate layer and the emulsion polymerization for forming the outer layer. Further, one or more stages of emulsion polymerization may be carried out after the emulsion polymerization for forming the outer layer.

[0086] (Emulsifier) Examples of the emulsifier used in the emulsion polymerization include anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, polymer emulsifiers, etc. These emulsifiers may be used alone or in combination of two or more.

[0087] Examples of anionic emulsifiers include, for example, 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 alkyl diphenyl ether disulfonate; alkyl aryl sulfonate salts such as ammonium dodecyl benzene sulfonate and sodium dodecyl naphthalene sulfonate; polyoxyethylene alkyl sulfonate salts; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkyl aryl sulfate salts; dialkyl sulfosuccinates; aryl sulfonic acid-formalin condensates; fatty acid salts such as ammonium laurate and sodium stearate; bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salts, propenyl-alkyl sulfosuccinate ester salts, (meth)acrylic acid polyoxyethylene sulfonate salts, (meth)acrylic acid polyoxyethylene phosphonate salts, allyloxy methyl alkyloxy polyoxyethylene sulfonate salts and other sulfate esters having an allyl group or salts thereof; allyloxy methyl alkoxy ethyl polyoxyethylene sulfate salts, polyoxyalkylene alkenyl ether ammonium sulfate salts, and the like, but are not limited to such examples only.

[0088] Examples of nonionic emulsifiers include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl 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, allyloxy methyl alkoxy ethyl hydroxy polyoxyethylene, polyoxyalkylene alkenyl ethers, and the like, but are not limited to such examples only.

[0089] Examples of cationic emulsifiers include, for example, alkyl ammonium salts such as dodecyl ammonium chloride, and the like, but are not limited to such examples only.

[0090] Examples of the amphoteric emulsifier include, but are not limited to, betaine ester type emulsifiers.

[0091] Examples of the polymeric emulsifier include, but are not limited to, poly(meth)acrylate salts such as sodium polyacrylate; polyvinyl alcohol; polyhydroxyalkyl (meth)acrylates such as polyhydroxyethyl acrylate; and copolymers having, as copolymerization components, one or more of the monomers constituting these polymers.

[0092] From the viewpoint of further improving water resistance and image uniformity, an emulsifier having a polymerizable group, that is, a so-called reactive emulsifier, is preferable as the above emulsifier. From the viewpoint of environmental protection, a non-nonylphenyl type emulsifier is preferable.

[0093] Examples of the reactive emulsifier include propenyl-alkyl sulfosuccinate salts, (meth)acrylic acid polyoxyethylene sulfonate salts, (meth)acrylic acid polyoxyethylene phosphonate salts [e.g., manufactured by Sanyo Chemical Industries, Ltd., trade name: Eleminol RS-30, etc.], polyoxyethylene alkyl propenyl phenyl ether sulfonate salts [e.g., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aquaron HS-10, etc.], sulfonate salts of allyloxymethyl alkyloxy polyoxyethylene [e.g., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aquaron KH-10, etc.], sulfonate salts of allyloxymethyl nonylphenoxyethyl hydroxy polyoxyethylene [e.g., manufactured by ADEKA Corporation, trade names: Adeka Liasol SR-10, SR-20, SR-30, etc.], sulfuric acid ester salts of allyloxymethyl alkoxyethyl hydroxy polyoxyethylene [e.g., manufactured by ADEKA Corporation, trade names: Adeka Liasol SR-10, SR-30, etc.], sulfonate salts of bis(polyoxyethylene polycyclic phenyl ether) methacrylate [e.g., manufactured by Nippon Emulsifier Co., Ltd., trade name: Antox MS-60, etc.], allyloxymethyl alkoxyethyl hydroxy polyoxyethylene [e.g., manufactured by ADEKA Corporation, trade name: Adeka Liasol ER-20, etc.], polyoxyethylene alkyl propenyl phenyl ether [e.g., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aquaron RN-20, etc.], allyloxymethyl nonylphenoxyethyl hydroxy polyoxyethylene [e.g., manufactured by ADEKA Corporation, trade name: Adeka Liasol NE-10, etc.], etc., but are not limited to such examples only.

[0094] From the viewpoint of improving polymerization stability, the amount of the emulsifier per 100 parts by mass of the monomer component is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, still more preferably 2 parts by mass or more, and particularly preferably 3 parts by mass or more. From the viewpoint of improving water resistance, it is preferably 10 parts by mass or less, more preferably 6 parts by mass or less.

[0095] (Polymerization initiator) Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-diaminopropane) hydrochloride, 4,4-azobis(4-cyanovaleric acid), 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. However, the present invention is not limited to these examples. These polymerization initiators may be used alone or in combination of two or more thereof.

[0096] From the viewpoint of increasing the polymerization rate and reducing the residual amount of unreacted monomer components, the amount of the polymerization initiator per 100 parts by mass of the monomer component is preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more. From the viewpoint of improving water resistance, it is preferably 1 part by mass or less, more preferably 0.5 part by mass or less.

[0097] The method for adding the polymerization initiator is not particularly limited. Examples of the addition method include batch charging, divided charging, and continuous dropping. Further, from the viewpoint of accelerating the end time of the polymerization reaction, a part of the polymerization initiator may be added before or after the completion of the addition of the monomer component into the reaction system.

[0098] In addition, in order to accelerate the decomposition of the polymerization initiator, a decomposition agent for the polymerization initiator such as a reducing agent such as sodium bisulfite and a transition metal salt such as ferrous sulfate may be added in an appropriate amount to the reaction system.

[0099] (Chain transfer agent) In addition, a chain transfer agent can be used to adjust the weight average molecular weight of the resin emulsion particles. Examples of the chain transfer agent 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, α-methylstyrene dimer, etc. These chain transfer agents may be used alone or in combination of two or more. From the viewpoint of appropriately adjusting the weight average molecular weight of the resin emulsion particles, the amount of the chain transfer agent per 100 parts by mass of the monomer component is preferably 0.01 to 10 parts by mass.

[0100] (Other conditions) In addition, additives such as a pH buffer, a chelating agent, and a film-forming aid may be added to the reaction system as necessary. The amount of the additive varies depending on its type and thus cannot be determined unconditionally. Usually, the amount of the additive per 100 parts by mass of the monomer component is preferably about 0.01 to 5 parts by mass, more preferably about 0.1 to 3 parts by mass.

[0101] The atmosphere during the emulsion polymerization of the monomer component is not particularly limited, but from the viewpoint of enhancing the efficiency of the polymerization initiator, it is preferably an inert gas such as nitrogen gas.

[0102] The polymerization temperature during the emulsion polymerization of the monomer component is not particularly limited, but usually, it is 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.

[0103] The polymerization time for the emulsion polymerization of the monomer component is not particularly limited and may be appropriately set according to the progress of the polymerization reaction. Usually, it is about 2 to 9 hours.

[0104] When the monomer component is emulsion-polymerized, part 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 adding the monomer component at the final stage, for example, it may be used between the first-stage polymerization reaction and the second-stage polymerization reaction, or it may be used at the end of the initial emulsion polymerization reaction.

[0105] Examples of the neutralizing agent include hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide; carbonates of alkali metals or alkaline earth metals such as sodium hydrogen carbonate and calcium carbonate; and alkaline substances such as organic amines such as ammonia, monomethylamine, and dimethylaminoethanol, but are not limited to such examples. Among these neutralizing agents, from the viewpoint of improving water resistance, volatile alkaline substances such as ammonia are preferred, and from the viewpoint of improving the storage stability of resin emulsion particles, sodium hydrogen carbonate is preferred. The neutralizing agent can be used, for example, as an aqueous solution.

[0106] When the monomer component is emulsion-polymerized, from the viewpoint of improving water resistance, an appropriate amount of a silane coupling agent may be used. Examples of the silane coupling agent include silane coupling agents having a polymerizable unsaturated bond such as a (meth)acryloyl group, a vinyl group, an allyl group, and a propenyl group, but are not limited to such examples. Note that “(meth)acryloyl” means “acryloyl” or “methacryloyl”.

[0107] By emulsion-polymerizing the monomer component as described above, an emulsion containing resin emulsion particles is obtained.

[0108] When forming an outer layer on the resin emulsion particles obtained above, from the viewpoint of forming a layer-separated structure within the resin emulsion particles, it is preferable to emulsion-polymerize the monomer component constituting the outer layer after the polymerization reaction rate in the production of the resin emulsion particles reaches 90% or more, preferably 95% or more.

[0109] After forming the inner layer of the resin emulsion particles and before forming the outer layer, within a range not inhibiting the object of the present invention, if necessary, a layer composed of other polymer components may be formed. Therefore, when manufacturing the resin emulsion particles contained in the inkjet ink of the present invention, after forming the inner layer of the resin emulsion particles and before forming the outer layer, within a range not inhibiting the object of the present invention, if necessary, a layer composed of other polymer components may be formed.

[0110] The monomer components used for constituting the outer layer can be the same as the monomer components used as the raw material of the inner layer of the above resin emulsion particles. Also, the method of emulsion polymerization and the polymerization conditions when forming the outer layer can be the same as the method and polymerization conditions when manufacturing the inner layer of the above resin emulsion particles.

[0111] Resin emulsion particles having an inner layer and an outer layer can be obtained as described above. Note that on the surface of the outer layer, within a range not inhibiting the object of the present invention, if necessary, a surface layer composed of other polymer components may be further formed.

[0112] After preparing the inner layer of the resin emulsion particles as described above, by forming an outer layer on the inner layer, resin emulsion particles having an inner layer and an outer layer can be obtained.

[0113] 1-3 Water The inkjet ink of the present invention is an aqueous ink containing water. The water content is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less, based on 100 parts by mass of the inkjet ink of the present invention.

[0114] 1-4 Solvent The inkjet ink of the present invention may contain an organic solvent. Examples of the organic solvent include glycols such as propylene glycol, 1,3-propanediol, glycerin, dipropylene glycol, tripropylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol; ethers of monoethylene glycol 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; ethers of monopropylene glycol such as monopropylene glycol monomethyl ether, monopropylene glycol monoethyl ether, monopropylene glycol monopropyl ether, monopropylene glycol monoisopropyl ether, monopropylene glycol monobutyl ether, and monopropylene glycol monoisobutyl ether; tripropylene glycol monomethyl ether; ethers of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4) such as monomethyl ether of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4), monoethyl ether of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4), monopropyl ether of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4), monoisopropyl ether of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4), monobutyl ether of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4), and monoisobutyl ether of polyethylene glycol (number of moles of EO added = 2 to 10, preferably 2 to 4);Ethers of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), such as monomethyl ether of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), monoethyl ether of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), monopropyl ether of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), monoisopropyl ether of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), monobutyl ether of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), monoisobutyl ether of polypropylene glycol (number of moles of ethylene oxide added = 2 to 10, preferably 2 to 4), etc. are mentioned. 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 are preferred. These organic solvents may be used alone or in combination of two or more kinds.; The content of the above organic solvent is preferably 1% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, based on 100 parts by mass of the ink for inkjet of the present invention.

[0115] 1-5 Pigment The ink for inkjet of the present invention preferably further contains a pigment. Examples of the pigment include organic pigments and inorganic pigments, and these may be used alone or in combination of two or more kinds. Further, if necessary, they can be used in combination with extender pigments.

[0116] Examples of organic pigments include azo pigments such as benzidine and Hansa yellow, diazo pigments, azomethine pigments, methine pigments, anthraquinone pigments, phthalocyanine pigments such as phthalocyanine blue, perinone pigments, perylene pigments, diketopyrrolopyrrole pigments, thioindigo pigments, iminoisoindoline pigments, isoindolinone pigments such as iminoisoindolinone, dioxazine pigments, quinacridone pigments such as quinacridone red and quinacridone violet, flavanthrone pigments, indanthrone pigments, anthrapyrimidine pigments, carbazole pigments, monoarylide yellow, diarylide yellow, benzimidazolone yellow, toluidine orange, naphthol orange, quinophthalone pigments, and the like. The hue is not particularly limited, and any chromatic pigments such as yellow, magenta, cyan, blue, red, orange, and green can be used. Specific examples include one or more product numbers selected from the group consisting of C.I. Pigment Yellow, C.I. Pigment Red, C.I. Pigment Orange, C.I. Pigment Violet, C.I. Pigment Blue, and C.I. Pigment Green. These organic pigments may be used alone or in combination of two or more.

[0117] Examples of inorganic pigments include titanium dioxide, antimony trioxide, zinc white, lithopone, lead white, red iron oxide, black iron oxide, chromium oxide green, carbon black, lead yellow, molybdenum red, ferric ferrocyanide (Prussian blue), ultramarine, lead chromate, and the like, as well as pigments having a flat shape such as mica, clay, aluminum powder, talc, and aluminum silicate, and extender pigments such as calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, and magnesium carbonate. Further, examples of carbon black include furnace black, thermal lamp black, acetylene black, channel black, and the like. These inorganic pigments may be used alone or in combination of two or more.

[0118] The amount of the pigment per 100 parts by mass of the non-volatile content of the ink for inkjet is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, from the viewpoint of improving the hiding property of the printed matter formed from the ink for inkjet of the present invention, and is preferably 90 parts by mass or less from the viewpoint of further improving the adhesion.

[0119] 1-6 Other components In the ink for inkjet of the present invention, other resin emulsion particles other than the resin emulsion particles contained in the ink for inkjet may be contained within a range not inhibiting the object of the present invention.

[0120] Further, in the ink for inkjet of the present invention, within a range not inhibiting the object of the present invention, for example, additives such as ultraviolet absorbers, ultraviolet stabilizers, fillers, surfactants, dispersants, thickeners, wetting agents, plasticizers, stabilizers, defoamers, dyes, antioxidants, preservatives, leveling agents, etc. may be contained in an appropriate amount. For example, acetylene glycol-based, polyether-modified silicone-based, fluorine-based surfactants, etc. can be added.

[0121] As the above dispersant, an ionic dispersant is preferable. The content of the above dispersant is preferably 0.1% by mass or more and 2.0% by mass or less, more preferably 0.2% by mass or more and 1.0% by mass or less, based on 100 parts by mass of the ink for inkjet of the present invention.

[0122] 1-7 Ink properties (Minimum film formation temperature) The minimum film formation temperature of the ink for inkjet of the present invention is preferably 40°C or lower, more preferably 20°C or lower, and still more preferably 0°C or lower, from the viewpoint of further improving the adhesion.

[0123] In the present specification, the minimum film formation temperature of the ink for inkjet means the temperature at which cracks occur when the ink for inkjet is applied with an applicator on a glass plate placed on a thermal gradient tester so as to have a thickness of 0.2 mm and dried.

[0124] (Non-volatile content) From the viewpoint of improving hiding power or color density, the non-volatile content in the inkjet ink of the present invention is preferably 5% by mass or more, more preferably 7% by mass or more, and from the viewpoint of improving storage stability, it is preferably 50% by mass or less, more preferably 40% by mass or less.

[0125] In this specification, the non-volatile content in the inkjet ink is obtained by weighing 1 g of the inkjet ink, drying it at a temperature of 150 °C for 1 hour with a hot air dryer, and taking the obtained residue as the non-volatile content. The formula is: [Non-volatile content in inkjet ink (% by mass)] =(〔Mass of residue〕÷〔1 g of inkjet ink〕)×100 means the value obtained based on this.

[0126] The inkjet ink of the present invention can be suitably used as an aqueous ink for inkjet. Further, it can be suitably used as an aqueous ink for a non-absorbent film described later. In particular, it can be suitably used as an aqueous ink for inkjet for a non-absorbent film. In the aqueous inkjet ink of the present invention, use as an aqueous ink for inkjet is preferred. Further, in the inkjet ink of the present invention, use as an aqueous ink for a non-absorbent film described later is preferred. Use as an aqueous ink for inkjet for a non-absorbent film is particularly preferred. The inkjet ink of the present invention is particularly suitable for printing on a recording medium for commercial printing using a film of a non-absorbent resin such as coated paper, a polyester film such as polyethylene terephthalate (PET), a polyvinyl chloride film, a polypropylene film such as a biaxially oriented polypropylene film (OPP), a polyethylene film, or a nylon film.

[0127] [Printed matter] The ink for inkjet of the present invention can be used for printing on printed materials such as conventionally known coated paper and resin films, and can be made into printed materials.

[0128] <Printed material> As the printed material, preferably, non-absorbent films such as non-absorbent coated paper, polyester films such as polyethylene terephthalate (PET), polyvinyl chloride films, polypropylene films such as biaxially stretched polypropylene film (OPP), polyethylene films, and nylon films are mentioned. Among them, more preferably, biaxially stretched polypropylene film (OPP) and polyethylene terephthalate (PET). Also, among non-absorbent films, those in which the surface on which the ink for inkjet of the present invention is printed is chemically or physically modified by corona treatment, anchor coat treatment, etc. are preferred. The adhesion to the aqueous ink of the present invention and the film formed by the ink for inkjet of the present invention becomes more excellent. Particularly preferred are corona-treated biaxially stretched polypropylene film (OPP) and corona-treated polyethylene terephthalate (PET).

[0129] According to the printed material obtained by printing the ink for inkjet of the present invention on a printed material, a printed material excellent in image uniformity, adhesion, and blocking resistance can be provided.

[0130] [Method for manufacturing printed material] The ink for inkjet of the present invention can be adopted for inkjet printing. As inkjet printing, for example, thermal method, piezo method, charge deflection control method (continuous discharge method), etc. are preferred.

[0131] According to the method for manufacturing a printed material using the ink for inkjet of the present invention, a method for manufacturing a printed material capable of manufacturing a printed material excellent in image uniformity, adhesion, and blocking resistance can be provided.

Examples

[0132] Next, the present invention will be described in more detail based on examples, but the present invention is not limited to such examples only. In the following examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0133] <Glass transition temperature of polymer component> The glass transition temperature (Tg) of the polymer component is determined by calculation based on the Fox equation represented by the formula: 1 / Tg = Σ(Wm / Tgm) / 100 〔In the formula, Wm represents the content rate (% by mass) of monomer m in the monomer component constituting the polymer component, and Tgm represents the glass transition temperature (absolute temperature: K) of the homopolymer of monomer m〕 and is obtained from the calculation based on the Fox equation.

[0134] <Acid value derived from carboxyl groups of resin emulsion particles> The acid value derived from the carboxyl groups of the resin emulsion particles was approximately obtained 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.

[0135] Example 1 716 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. In the dropping funnel, 209 parts of deionized water, 60 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA CORPORATION, trade name: ADEKA REASORB SR-10], 100 parts of cyclohexyl methacrylate, 250 parts of methyl methacrylate, 100 parts of styrene, 40 parts of n-butyl acrylate, and 10 parts of hydroxyethyl methacrylate were prepared to form a first-stage dropping pre-emulsion. 77 parts, which is 5% of the total amount of all monomer components, was added into the flask, and the temperature was raised to 70°C while gently blowing nitrogen gas, and 10 parts of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Thereafter, the remainder of the dropping pre-emulsion and 15 parts of a 5% aqueous solution of ammonium persulfate were uniformly dropped into the flask over 120 minutes.

[0136] After the dropping was completed, the content of the flask was maintained at 70 °C for 60 minutes. Subsequently, 209 parts of deionized water, 60 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA CORPORATION, trade name: ADEKA REASORB SR-10], 6 parts of acrylic acid, 134 parts of methyl methacrylate, 50 parts of styrene, 300 parts of 2-ethylhexyl acrylate, and 10 parts of hydroxyethyl methacrylate, and 15 parts of a 5% aqueous solution of ammonium persulfate were uniformly dropped into the flask over 120 minutes.

[0137] After the dropping was completed, the content of the flask was maintained at 70 °C for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to terminate the polymerization. After the obtained reaction solution was cooled to room temperature, an emulsion was prepared by filtering through a 300-mesh wire net. The content rate of the non-volatile matter in this emulsion was 45%, the acid value derived from the carboxyl group of the resin emulsion particles was 5.0 mgKOH / g, the glass transition temperature of the resin of the inner layer constituting the resin emulsion particles contained in the emulsion was 78 °C, and the glass transition temperature of the outer layer resin was -25 °C. The minimum film-forming temperature was 0 °C or lower, and the average particle diameter was 145 nm.

[0138] While stirring 16 parts of the obtained emulsion with a homodisper at a rotation speed of 1000 min -1 while stirring, 25 parts of a white paste, 30 parts of propylene glycol, 10 parts of tripropylene glycol monomethyl ether, 10 parts of diethylene glycol monobutyl ether, 0.2 part of a surfactant [manufactured by Shin-Etsu Chemical Co., Ltd., KF-6011], 1 part (0.5 part as a solid content) of polyvinylpyrrolidone K-30 (manufactured by Nippon Shokubai Co., Ltd., weight average molecular weight 70,000), and ion-exchanged water was added to make a total of 100 parts. After further stirring for 30 minutes, inkjet ink 1 was prepared by filtering through a 3-μm filter [manufactured by ADVANTEC, MCP-3-C10S]. The white paste was prepared by dispersing 411 parts of deionized water, 67 parts of a dispersant [manufactured by Nippon Shokubai Co., Ltd., Aquaric HL-415], 30 parts of 25% aqueous ammonia, 60 parts of propylene glycol, 1000 parts of titanium oxide [manufactured by Ishihara Sangyo Co., Ltd., CR-95], and 200 parts of glass beads (diameter 1 mm) in a disper at a rotational speed of 3000 min -1 for 120 minutes and then filtering through a 300-mesh wire netting.

[0139] Comparative Example 1 In Comparative Example 1, an inkjet ink C1 was prepared in the same manner as in Example 1, except that polyvinylpyrrolidone K-30 was changed to 2.5 parts (0.5 part as solid content) of anionic sodium polyacrylate [manufactured by Nippon Shokubai Co., Ltd., Aquaric DL-522, weight average molecular weight 200,000].[[]]

[0140] Comparative Example 2 In Comparative Example 2, an inkjet ink C2 was prepared in the same manner as in Example 1, except that polyvinylpyrrolidone K-30 was changed to 0.5 part (0.5 part as solid content) of nonionic polyvinyl alcohol [manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., JC-25, weight average molecular weight 110,000].[[]]

[0141] Comparative Example 3 In Comparative Example 3, an inkjet ink C3 was prepared in the same manner as in Example 1, except that polyvinylpyrrolidone K-30 was changed to 0.5 part (0.5 part as solid content) of nonionic polyethylene glycol [manufactured by Sumitomo Seika Chemicals Co., Ltd., PEO-1, weight average molecular weight 150,000].[[]]

[0142] Comparative Example 4 In Comparative Example 4, an inkjet ink C4 was prepared in the same manner as in Example 1, except that polyvinylpyrrolidone K-30 was changed to 0.5 part (0.5 part as solid content) of polyvinylpyrrolidone K-85 [manufactured by Nippon Shokubai Co., Ltd., weight average molecular weight 1,100,000].[[]]

[0143] Preparation of Inkjet Print In an environment of 25±1°C temperature and 30±5% relative humidity, the inkjet inks obtained in the examples and comparative examples were filled into a print evaluation device (manufactured by Genesis Corporation) equipped with an inkjet recording head "KJ4B-YH06WST-STDV" (manufactured by Kyocera Corporation). The following settings were made: head voltage 26 V, frequency 4 kHz, ejection liquid amount 12 pl, head temperature 32° C., resolution 600 dpi, and negative pressure −4.0 kPa. A corona-treated PET recording medium (Taiko Polyester Film FE2001, manufactured by Futamura Chemical Co., Ltd.) was fixed to a conveying table so that the longitudinal direction of the recording medium was the same as the conveying direction. A print command was transferred to the print evaluation device, and a solid image with a print volume of 100% (12 pl, 600×600 dpi) was printed on a recording medium using the inkjet ink by the inkjet recording method. Immediately afterwards, the film was dried in a dryer at 70°C for 10 seconds.

[0144] The following physical properties were examined using the images obtained. The results are shown in Table 1. Any physical property rated as x was determined to be unsatisfactory.

[0145] (1) Discharge stability (image uniformity) The solid image was visually observed and the uniformity of the image was evaluated according to the following criteria. .circle.: No white streaks or color unevenness in solid images. A: Some white streaks are observed in the solid image. ×: White streaks and color unevenness are noticeable in solid images.

[0146] (2) Blocking resistance A PET sheet with an untreated corona surface was placed on the printed surface of a solid image and subjected to a pressure of 2N / cm at 25°C. 2 After applying the load for 1 hour, the specimen was quickly peeled off and the blocking resistance was evaluated according to the following criteria. ◎: No resistance at all ○: Almost no resistance ×: Significant resistance

[0147] (3) Scratch resistance (adhesion) The printed matter with a solid image was rubbed with a fingernail, and the scratch resistance (adhesion) was confirmed according to the following criteria. ◎: No peeling occurs on the printed surface at all. ○: Almost no peeling occurs on the printed surface. ×: Peeling occurs on the printed surface.

[0148]

Table 1

[0149] From the results in Table 1, it was found that the inkjet ink of the examples was superior in ejection stability and blocking resistance of the formed image compared to the inkjet ink of the comparative examples.

Industrial Applicability

[0150] According to the inkjet ink of the present invention, an inkjet ink excellent in ejection stability and blocking resistance of the formed image can be provided. The inkjet ink of the present invention can be suitably used for printing on a recording medium for commercial printing, particularly using a non-absorbent resin film such as coated paper, a polyester film such as polyethylene terephthalate (PET), a polyvinyl chloride film, a polypropylene film such as a biaxially stretched polypropylene film (OPP), a polyethylene film, or a nylon film.

Claims

1. A nonionic water-soluble polymer compound containing an amide bond, resin emulsion particles, water, and an organic solvent and containing, the nonionic water-soluble polymer compound containing an amide bond is polyvinylpyrrolidone having a weight average molecular weight of 5,000 to 500,000, the organic solvent contains at least one selected from the group consisting of propylene glycol, diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, and diethylene glycol monoisobutyl ether, the total content of the organic solvent is 10% by mass or more and 60% by mass or less based on 100% by mass of the inkjet ink, the minimum film formation temperature is 40 °C or lower, further containing a polyether-modified silicone-based surfactant, an aqueous inkjet ink for a non-absorbent film Inkjet ink.

2. The content of the nonionic water-soluble polymer compound containing an amide bond is 0.05 to 10% by mass The inkjet ink according to claim 1.

3. The resin emulsion particles contain a (meth)acrylic polymer The inkjet ink according to claim 1 or 2.

4. The acid value derived from the carboxyl group of the resin emulsion particles is 0 to 6 mgKOH / g The inkjet ink according to any one of claims 1 to 3.

5. Further containing a pigment, The amount of the pigment per 100 parts by mass of the non-volatile content of the ink for inkjet is 50 parts by mass or more and 90 parts by mass or less. The ink for inkjet according to any one of claims 1 to 4.

6. Furthermore, it contains a dispersant, The content of the dispersant is 0.1% by mass or more and 2.0% by mass or less with respect to 100% by mass of the ink for inkjet. The ink for inkjet according to any one of claims 1 to 5.

7. The non-volatile content in the ink for inkjet is 5% by mass or more and 50% by mass or less. The ink for inkjet according to any one of claims 1 to 6.

Images