JP7340467B2 - Resin emulsion for water-based ink - Google Patents

Description

The present invention relates to a resin emulsion for aqueous ink. More specifically, the present invention relates to a resin emulsion for aqueous ink, a method for producing the same, and an aqueous ink containing the resin emulsion for aqueous ink. The water-based ink of the present invention can be used, for example, as an inkjet water-based ink, a flexographic printing ink, an offset printing ink, a lithographic printing ink, a gravure printing ink, a screen printing ink, and especially as an inkjet water-based ink. It can be suitably used.

Inks are broadly classified into 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 solvent component.

Organic solvent-based ink compositions have good water resistance because the main component of the solvent is an organic solvent. Because of this, water-based inks are attracting attention.

An aqueous ink composition containing a resin emulsion containing emulsion particles as an essential component, as an aqueous ink composition that has excellent storage stability and forms a coating film that is comprehensively excellent in curl prevention, scratch resistance, water resistance, and weather resistance. The ink composition further contains at least one water-insoluble curable compound selected from the group consisting of water-insoluble curable monomers and water-insoluble curable oligomers, and constitutes the emulsion particles. An aqueous ink composition has been proposed in which the glass transition temperature of the polymer is 0 to 120°C, and the minimum film forming temperature of the aqueous ink composition is 0 to 30°C (for example, Patent Document 1 reference).

The water-based ink composition forms a coating film that is comprehensively excellent in anti-curling properties, scratch resistance, water resistance, and weather resistance, so it can be used, for example, on paper, resin sheets or films, metal plates, wood plates, Desired information such as characters, patterns, colors, etc. are formed on a base material made of materials such as leather by inkjet printing, flexographic printing, offset printing, lithographic printing, gravure printing, screen printing, ink ribbon, etc. It can be suitably used in industrial inks such as printing inks when imparting design properties, scratch resistance, water resistance, weather resistance, etc. to objects.

In recent years, there has been a desire to develop water-based inks that have not only excellent scratch resistance but also flexibility, adhesion to substrates, and blocking resistance.

Patent No. 6258662

The present invention has been made in view of the above-mentioned prior art, and provides a water-based ink having excellent not only scratch resistance but also flexibility, adhesion to a substrate, and blocking resistance, and the water-based ink. It is an object of the present invention to provide a resin emulsion for aqueous ink that can be suitably used and a method for producing the same.

The present invention
(1) A resin emulsion for an aqueous ink containing emulsion particles having an inner layer and an outer layer, in which the glass transition temperature of the polymer constituting the inner layer is 80°C or higher, and the glass transition temperature of the polymer constituting the outer layer is A resin emulsion for water-based ink, characterized by a temperature of 10°C or less,
(2) A method for producing a resin emulsion for an aqueous ink containing emulsion particles having an inner layer and an outer layer, the method comprising: forming emulsion particles constituting the inner layer in which the glass transition temperature of the polymer is 80° C. or higher; A method for producing a resin emulsion for an aqueous ink, which comprises forming an outer layer having a polymer glass transition temperature of 10° C. or less on emulsion particles constituting the inner layer, and (3) the aqueous ink according to (1) above. The present invention relates to an aqueous ink containing a resin emulsion for use in water.

According to the present invention, a water-based ink that has excellent not only scratch resistance but also flexibility, adhesion to a substrate, and blocking resistance, and a water-based ink that can be suitably used for the water-based ink A resin emulsion and method for making the same is provided.

As described above, the resin emulsion for water-based ink of the present invention is a resin emulsion for water-based ink containing emulsion particles having an inner layer and an outer layer, and the glass transition temperature of the polymer constituting the inner layer is 80 ° C. or higher, The glass transition temperature of the polymer constituting the outer layer is 10° C. or lower.

Since the aqueous ink of the present invention uses the resin emulsion for aqueous ink, it has excellent flexibility, blocking resistance, adhesion to a substrate, and scratch resistance.

In the resin emulsion for water-based ink of the present invention, after forming emulsion particles constituting the inner layer in which the glass transition temperature of the polymer is 80 °C or higher, the glass transition temperature of the polymer is 10 °C or higher on the emulsion particles constituting the inner layer. It can be prepared by forming an outer layer that is:

The inner layer of the emulsion particles can be prepared by emulsion polymerization of monomer components for the inner layer.

Monomers used for the inner layer monomer component include monofunctional monomers and polyfunctional monomers. The monofunctional monomer and the polyfunctional monomer may be used alone or in combination. Although it is possible to use only a polyfunctional monomer as the monomer component for the inner layer, usually only a monofunctional monomer or a combination of a monofunctional monomer and a polyfunctional monomer are used.

Representative examples of monofunctional monomers include radically polymerizable monomers such as ethylenically unsaturated monomers. Examples of ethylenically unsaturated monomers include alkyl (meth)acrylates, hydroxyl group-containing (meth)acrylates, aralkyl (meth)acrylates, alkoxyalkyl (meth)acrylates, carboxyl group-containing ethylenically unsaturated monomers, and oxo group-containing ethylenic monomers. Unsaturated monomers, fluorine atom-containing ethylenically unsaturated monomers, nitrogen atom-containing ethylenically unsaturated monomers, styrene monomers, epoxy group-containing ethylenically unsaturated monomers, silane group-containing ethylenically unsaturated monomers, carbonyl group-containing ethylenically unsaturated monomers Examples include saturated monomers and ethylenically unsaturated monomers containing an aziridinyl group, but the present invention is not limited to these examples. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

In the present invention, "(meth)acrylate" means "acrylate" or "methacrylate". "(Meth)acrylic" means "acrylic" or "methacrylic". Moreover, "(meth)acryloyl" means "acryloyl" or "methacryloyl".

Examples of the alkyl (meth)acrylate include 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, n-lauryl (meth)acrylate, dodecyl (meth)acrylate Acrylate, stearyl (meth)acrylate, 2-(acetoacetoxy)ethyl (meth)acrylate, 2-ethylhexylcarbitol (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-methylcyclohexylmethyl ( Examples include alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms, such as meth)acrylate, tert-butylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate; however, the present invention is limited to such examples. It is not limited to. These monomers may be used alone or in combination of two or more.

Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxy Examples include hydroxyalkyl (meth)acrylates in which the hydroxyalkyl group has 1 to 18 carbon atoms, such as butyl (meth)acrylate and caprolactone-modified hydroxy(meth)acrylate, but the present invention is limited only to such examples. It's not a thing. These monomers may be used alone or in combination of two or more.

Examples of aralkyl (meth)acrylates include aralkyl groups having an aralkyl group having 7 to 18 carbon atoms, such as benzyl (meth)acrylate, phenylethyl (meth)acrylate, methylbenzyl (meth)acrylate, and naphthylmethyl (meth)acrylate. Examples include (meth)acrylate, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

Examples of alkoxyalkyl (meth)acrylates include methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, trimethylolpropane tripropoxy (meth)acrylate, etc. However, the invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

Examples of carboxyl group-containing ethylenically unsaturated monomers include (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monobutyl ester, and itacon. Examples include carboxyl group-containing aliphatic monomers such as acid monomethyl ester, itaconate monobutyl ester, vinylbenzoic acid, oxalic acid monohydroxyethyl (meth)acrylate, and carboxyl group-terminated caprolactone-modified (meth)acrylate. is not limited to these examples. These monomers may be used alone or in combination of two or more. Among these carboxyl group-containing ethylenically unsaturated 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 of emulsion particles.

Examples of oxo group-containing ethylenically unsaturated monomers include (di)ethylene glycol (meth)acrylate, ethylene glycol methoxy (meth)acrylate, diethylene glycol (meth)acrylate, and diethylene glycol methoxy (meth)acrylate. Examples include (meth)acrylate, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

Examples of fluorine atom-containing ethylenically unsaturated monomers include trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, perfluorobutylethyl (meth)acrylate, and perfluoroisononyl. Examples include fluorine atom-containing alkyl (meth)acrylates having a fluorine atom in the ester moiety, such as ethyl (meth)acrylate and perfluorooctylethyl (meth)acrylate, but the present invention is not limited to such examples. do not have. These monomers may be used alone or in combination of two or more.

Examples of nitrogen atom-containing ethylenically unsaturated monomers include (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-dimethylaminopropyl acrylamide, acrylamide compounds such as diacetone acrylamide, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, nitrogen atom-containing (meth)acrylate compounds such as ethylene oxide addition (meth)acrylate of morpholine, N-vinylpyrrolidone, N-vinylpyridine, N-vinylimidazole, N-vinylpyrrole, N-vinyloxazolidone, N-vinylsuccinimide, N-vinylmethylcarbamate, N,N-methylvinylacetamide, (meth)acryloyloxyethyltrimethylammonium chloride, Examples include 2-isopropenyl-2-oxazoline, 2-vinyl-2-oxazoline, and (meth)acrylonitrile, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

Examples of styrenic monomers include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, o-tert-butyl Styrene, m-tert-butylstyrene, p-tert-butylstyrene and other alkylkylstyrenes in which the alkyl group has 1 to 4 carbon atoms, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-ethoxy Alkoxystyrene in which the alkoxy group has 1 to 4 carbon atoms, such as styrene, m-ethoxystyrene, p-ethoxystyrene, o-tert-butoxystyrene, m-tert-butoxystyrene, and p-tert-butoxystyrene, o- Styrene containing halogen atoms such as fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, o Examples include acetoxystyrenes such as -acetoxystyrene, m-acetoxystyrene, and p-acetoxystyrene, and vinyltoluene, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

Styrenic monomers have functional groups such as alkyl groups such as methyl groups and tert-butyl groups, nitro groups, nitrile groups, alkoxyl groups, acyl groups, sulfone groups, hydroxyl groups, and halogen atoms in the benzene ring. good.

Among styrenic monomers, styrene, alkylkylstyrene whose alkyl group has 1 to 4 carbon atoms, and alkoxy group Alkoxystyrene having 1 to 4 carbon atoms is preferred, alkylkylstyrene having styrene and an alkyl group having 1 to 4 carbon atoms is more preferred, and alkylkylstyrene having styrene and an alkyl group having 1 or 2 carbon atoms. is more preferred, and styrene is even more preferred.

Examples of the epoxy group-containing ethylenically unsaturated monomer include glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, glycidyl allyl ether, oxocyclohexylmethyl (meth)acrylate, and 3,4-epoxycyclohexylmethyl (meth)acrylate. Examples include epoxy group-containing (meth)acrylates such as acrylates, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

Examples of the silane group-containing ethylenically unsaturated monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, Examples include vinyltrichlorosilane, γ-(meth)acryloyloxypropylhydroxysilane, γ-(meth)acryloyloxypropylmethylhydroxysilane, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

Examples of carbonyl group-containing ethylenically unsaturated monomers include acrolein, homylstyrene, vinyl ethyl ketone, (meth)acryloxyalkyl propenal, acetonyl (meth)acrylate, diacetone (meth)acrylate, 2-hydroxypropyl (meth) ) acrylate acetylacetate, butanediol-1,4-acrylate acetylacetate, etc., but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

Examples of the aziridinyl group-containing ethylenically unsaturated monomer include (meth)acryloylaziridine and 2-aziridinylethyl (meth)acrylate, but the present invention is not limited to these examples. . These monomers may be used alone or in combination of two or more.

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, tripropylene Di(meth)acrylate of polyhydric alcohol having 1 to 10 carbon atoms, such as glycol di(meth)acrylate; polyethylene glycol di(meth)acrylate with an added mole of ethylene oxide of 2 to 50, and a polyethylene glycol di(meth)acrylate with an added mole of propylene oxide of 2 ~50 polypropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and other alkyl di(meth)acrylates with 2 to 50 moles of alkylene oxide groups having 2 to 4 carbon atoms; ethoxylated glycerin triacrylate; (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, trimethylolpropane triethoxy Tri(meth)acrylates of polyhydric alcohols having 1 to 10 carbon atoms such as tri(meth)acrylate; pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, etc. Tetra(meth)acrylate of polyhydric alcohol having 1 to 10 carbon atoms; Penta(meth)acrylate of polyhydric alcohol having 1 to 10 carbon atoms such as pentaerythritol penta(meth)acrylate, dipentaerythritol (monohydroxy) penta(meth)acrylate meth)acrylate; Hexa(meth)acrylate of polyhydric alcohol having 1 to 10 carbon atoms such as pentaerythritol hexa(meth)acrylate; Bisphenol A di(meth)acrylate, 2-(2'-vinyloxyethoxyethyl)(meth)acrylate; ) acrylates, epoxy group-containing (meth)acrylates such as epoxy (meth)acrylates; polyfunctional (meth)acrylates such as urethane (meth)acrylates, but are not limited to these examples. These polyfunctional monomers may be used alone, or two or more types may be used in combination.

In the present invention, from the viewpoint of imparting ultraviolet stability or ultraviolet absorption to emulsion particles, monomers such as ultraviolet stable monomers and ultraviolet absorbing monomers are used as monomer components for the inner layer within a range that does not impede the purpose of the present invention. It is preferable to include it.

Examples of UV-stable monomers include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, -(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, Examples include 6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more. Among these UV-stable monomers, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethyl Piperidyl group-containing (meth)acrylates such as piperidine and 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine are preferred.

Examples of the ultraviolet absorbing monomer include benzotriazole ultraviolet absorbing monomers and benzophenone ultraviolet absorbing monomers, but the present invention is not limited to these examples. These monomers may be used alone or in combination of two or more.

Examples of benzotriazole-based ultraviolet 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, 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)acryloyloxyethyl phenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(β-(meth)acryloyloxyethoxy)-3'-tert-butylphenyl]-4-tert-butyl Examples include -2H-benzotriazole, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

Examples of benzophenone-based ultraviolet absorbing monomers include 2-hydroxy-4-(meth)acryloyloxybenzophenone, 2-hydroxy-4-[2-hydroxy-3-(meth)acryloyloxy]propoxybenzophenone, and 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 and the like, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

The monomer component for the inner layer preferably contains an alkyl (meth)acrylate and a styrene monomer from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is more preferable to contain an alkyl (meth)acrylate and a styrenic monomer having a number of 1 to 8.

The content of alkyl (meth)acrylate in the monomer component for the inner layer is preferably 0 to 80% by mass, more preferably 0 to 80% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is 3 to 70% by mass.

The content of the styrene monomer in the monomer component for the inner layer is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is 97% by mass.

The monomer component for the inner layer may contain a carboxyl group-containing ethylenically unsaturated monomer such as (meth)acrylic acid, but it does not improve flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. From the viewpoint of improving The lower limit is 0% by mass.

A method for emulsion polymerizing the monomer components for the inner layer is, for example, an aqueous medium containing water and a water-soluble organic solvent such as a lower alcohol such as methanol, or an emulsifier is dissolved in a medium such as water, and the monomer component for the inner layer is polymerized under stirring. Examples include a method in which components and a polymerization initiator are dropped, and a method in which a monomer component for the inner layer that has been emulsified in advance using an emulsifier and water is dropped into water or an aqueous medium. However, the present invention is limited to such methods. It is not limited. Note that the amount of the medium may be appropriately set in consideration of the amount of nonvolatile components contained in the resulting resin emulsion. The medium may be charged to the reaction vessel in advance or may be used as a pre-emulsion. Further, the medium may be used when a resin emulsion is produced by emulsion polymerization of monomer components for the inner layer, if necessary.

When emulsion polymerizing the monomer components for the inner layer, the emulsion polymerization may be performed after mixing the monomer components for the inner layer, the emulsifier, and the medium. The emulsion polymerization may be carried out after preparing the inner layer, or the emulsion polymerization may be carried out by mixing at least one of the monomer components for the inner layer, the emulsifier, and the medium with the remaining pre-emulsion. The monomer components for the inner layer, the emulsifier, and the medium may be added all at once, added in portions, or added dropwise continuously.

Examples of emulsifiers include anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, polymer emulsifiers, etc. These emulsifiers may be used alone, or two or more types may be used in combination.

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 alkyl diphenyl ether disulfonate; ammonium dodecylbenzene sulfonate, sodium dodecyl naphthalene sulfonate, etc. alkylaryl sulfonate salt; polyoxyethylene alkyl sulfonate salt; polyoxyethylene alkyl sulfate salt; polyoxyethylene alkylaryl sulfate salt; dialkyl sulfosuccinate; aryl sulfonic acid-formalin condensate; ammonium laurylate, sodium stearate, etc. Fatty acid salt; bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salt, propenyl-alkyl sulfosuccinate salt, (meth)acrylic acid polyoxyethylene sulfonate salt, (meth)acrylic acid polyoxyethylene phosphonate salt, allyl Allyl group-containing sulfate esters or their salts such as oxymethylalkyloxypolyoxyethylene sulfonate salts; polyoxyethylene alkylphenyl ether sulfate salts, allyloxymethylalkoxyethyl polyoxyethylene sulfate ester salts, polyoxyalkylene alkenyl ethers Examples include ammonium sulfate salts, but the present invention is not limited to such examples.

Examples of nonionic emulsifiers include 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, ethylene oxide and aliphatic Examples include condensates with amines, allyloxymethylalkoxyethylhydroxypolyoxyethylene, and polyoxyalkylene alkenyl ethers, but the present invention is not limited to these examples.

Examples of the cationic emulsifier include alkyl ammonium salts such as dodecylammonium chloride, but the present invention is not limited to such examples.

Examples of amphoteric emulsifiers include betaine ester emulsifiers, but the present invention is not limited to these examples.

Examples of polymer emulsifiers include poly(meth)acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl (meth)acrylates such as polyhydroxyethyl acrylate; Examples include copolymers containing one or more of these as a copolymerization component, but the present invention is not limited to such examples.

In addition, from the viewpoint of improving flexibility, blocking resistance, adhesion to substrates, and scratch resistance, emulsifiers having a polymerizable group, that is, so-called reactive emulsifiers, are preferable, and from the viewpoint of environmental protection, non-nonyl Emulsifiers of the phenyl type are preferred.

Examples of the reactive emulsifier include propenyl-alkyl sulfosuccinate salts, (meth)acrylic acid polyoxyethylene sulfonate salts, polyoxyethylene alkyl propenyl phenyl ether ammonium sulfate [for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon HS-10, Aqualon BC-10, etc.], allyloxymethylalkyloxypolyoxyethylene sulfonate salts (for example, Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon KH-10, etc.), allyloxymethylnonylphenoxy Ethylhydroxypolyoxyethylene sulfonate salts (for example, manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasorp SE-10, etc.), allyloxymethylalkoxyethylhydroxypolyoxyethylene sulfate salts (for example, manufactured by ADEKA Co., Ltd., product name: ADEKA Reasoap SE-10), Product name: Adekaria Soap SR-10, SR-20, SR-30, etc.], Bis(polyoxyethylene polycyclic phenyl ether) methacrylated sulfonate salt [For example, manufactured by Nippon Nyukazai Co., Ltd., product name: Antox MS -60, etc.], allyloxymethylalkoxyethylhydroxypolyoxyethylene [for example, manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap ER-10, ER-20, ER-30, ER-40, etc.], polyoxyethylene Alkyl propenyl phenyl ether [for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon RN-20], allyloxymethylnonyl phenoxyethyl hydroxypolyoxyethylene [for example, manufactured by ADEKA Co., Ltd., trade name: Adecaria] Soap NE-10, NE-20, NE-30, etc.], but the present invention is not limited to these examples. These reactive emulsifiers may be used alone or in combination of two or more.

The amount of emulsifier per 100 parts by mass of the monomer component for the inner 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. From the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance, the amount is 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. .

It is preferable to use a polymerization initiator when polymerizing the monomer component for the inner layer. Examples of the polymerization initiator include azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), and 2,2-azobis( Azo compounds such as 2-diaminopropane) hydrochloride, 4,4-azobis(4-cyanovaleric acid), and 2,2-azobis(2-methylpropionamidine); persulfates such as potassium persulfate; hydrogen peroxide , benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, ammonium peroxide, and the like, but the present invention is not limited to these examples. These polymerization initiators may be used alone or in combination of two or more.

The amount of the polymerization initiator per 100 parts by mass of the inner layer monomer component is preferably 0.01 part by mass or more, more preferably 0. The amount is .05 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1 part by mass or less, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. Preferably it is 0.8 parts by mass or less, more preferably 0.5 parts by mass or less.

The method of adding the polymerization initiator is not particularly limited. Examples of the addition method include batch charging, divided charging, continuous dropping, and the like. In addition, from the viewpoint of advancing the end time of the polymerization reaction, a portion of the polymerization initiator may be added before or after the end of adding the monomer component for the inner layer into the reaction system.

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

Further, in order to adjust the weight average molecular weight of the resin constituting the emulsion particles, a chain transfer agent can be used in the monomer component for the inner layer. When a chain transfer agent is used as a monomer component for the inner layer, it is generally possible to lower the molecular weight of the resin constituting the emulsion particles, compared to a case where a chain transfer agent is not used as a monomer component for the inner layer. Examples of chain transfer agents include 2-ethylhexyl thioglycolate, tert-dodecylmercaptan, n-octylmercaptan, n-dodecylmercaptan, mercaptoacetic acid, β-mercaptopropionic acid, 2-mercaptoethanol, α-methylstyrene, α -methylstyrene dimer, etc., but the present invention is not limited to such examples. These chain transfer agents may be used alone or in combination of two or more. The amount of the chain transfer agent per 100 parts by mass of the monomer component for the inner layer is preferably 0.01 to 10 parts by mass from the viewpoint of adjusting the weight average molecular weight of the resin constituting the emulsion particles.

If necessary, additives such as a pH buffer, a chelating agent, and a film-forming aid may be added to the reaction system when polymerizing the monomer component for the inner layer. The amount of additive cannot be determined unconditionally since it varies depending on the type of additive. Usually, the amount of additive per 100 parts by mass of the inner layer monomer component is preferably about 0.01 to 5 parts by mass, more preferably about 0.1 to 3 parts by mass.

The atmosphere during emulsion polymerization of the monomer component for the inner layer is not particularly limited, but from the viewpoint of increasing the efficiency of the polymerization reaction, an inert gas such as nitrogen gas is preferable.

The polymerization temperature during emulsion polymerization of the monomer component for the inner layer is not particularly limited, but is usually preferably 10 to 100°C, more preferably 40 to 95°C, and even more preferably 50 to 60°C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

The polymerization time for emulsion polymerization of the monomer components for the inner layer is not particularly limited and may be appropriately set depending on the progress of the polymerization reaction, but is usually about 2 to 8 hours.

In addition, when emulsion polymerizing the monomer component for the inner layer, some or all of the acidic groups possessed by the resulting polymer may be neutralized with a neutralizing agent. The neutralizing agent may be used before polymerizing the monomer components for the inner layer, during or after the emulsion polymerization reaction.

Examples of neutralizing agents include hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide; carbonates of alkali metals and alkaline earth metals such as calcium carbonate; organic amines such as ammonia and monomethylamine; Examples include alkaline substances, but the present invention is not limited to such examples. Among these neutralizing agents, volatile alkaline substances such as ammonia are preferred from the viewpoint of improving flexibility, blocking resistance, adhesion to substrates, and scratch resistance. The neutralizing agent may be used in the form of an aqueous solution.

Further, when emulsion polymerizing the monomer component for the inner layer, a silane coupling agent may be used in an appropriate amount. Examples of the silane coupling agent include silane coupling agents having polymerizable unsaturated bonds such as (meth)acryloyl groups, vinyl groups, allyl groups, and propenyl groups, but the present invention is not limited to such examples. It is not limited.

By emulsion polymerizing the monomer components for the inner layer as described above, a resin emulsion containing emulsion particles constituting the inner layer can be obtained. The polymer constituting the inner layer may have a crosslinked structure.

In the emulsion particles constituting the inner layer, the glass transition temperature of the polymer constituting the inner layer is preferably 80°C or higher, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. 85°C or higher, and the upper limit of the glass transition temperature is preferably 120°C or lower, more preferably 110°C from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is as follows. The glass transition temperature of the polymer constituting the inner layer can be easily adjusted by adjusting the type and amount of the monomer used in the monomer component for the inner layer.

In this specification, the glass transition temperature (Tg) of a polymer is expressed by the formula:
1/Tg=Σ(Wm/Tgm)/100
[In the formula, Wm indicates the content (mass%) of monomer m in the inner layer monomer component constituting the resin layer, and Tgm indicates the glass transition temperature (absolute temperature: K) of the homopolymer of monomer m.]
It means the temperature determined based on the Fox equation expressed by

In this specification, the glass transition temperature of a polymer means the glass transition temperature determined based on the Fox equation, unless otherwise specified.

The glass transition temperature of the entire polymer constituting the emulsion particles having an inner layer and an outer layer is determined by using the glass transition temperature of a homopolymer consisting of the monomers used for all the monomer components used to form the inner layer and outer layer. means the glass transition temperature determined based on the above-mentioned Fox equation.

Regarding monomers whose glass transition temperature is unknown, such as special monomers and polyfunctional monomers, if the total amount of monomers whose glass transition temperature is unknown in the monomer components is 10% by mass or less, the glass The glass transition temperature can be determined using only monomers with known transition temperatures. If the total amount of monomers whose glass transition temperature is unknown in the monomer components exceeds 10% by mass, the glass transition temperature of the polymer can be determined by differential scanning calorimetry (DSC), differential calorimetry (DTA), or thermal analysis. It is determined by mechanical analysis (TMA), etc.

The glass transition temperature of the polymer is, for example, 105°C for a homopolymer of methyl methacrylate, -70°C for a homopolymer of 2-ethylhexyl acrylate, -56°C for a homopolymer of n-butyl acrylate, and -56°C for a homopolymer of n-butyl methacrylate. 20°C, 55°C for 2-hydroxyethyl methacrylate homopolymer, 95°C for acrylic acid homopolymer, 130°C for methacrylic acid homopolymer, 100°C for styrene homopolymer, 4-methacryloyloxy-1,2, The temperature is 130°C for the homopolymer of 2,6,6-pentamethylpiperidine and 83°C for the homopolymer of cyclohexyl methacrylate.

Next, an outer layer monomer component is added to the resin emulsion containing emulsion particles constituting the inner layer, and the outer layer monomer component is emulsion polymerized to obtain a resin emulsion containing emulsion particles having an inner layer and an outer layer. .

When forming an outer layer on the emulsion particles constituting the inner layer contained in the resin emulsion obtained above, the inner layer can be formed by emulsion polymerizing the monomer component for the outer layer in the resin emulsion in the same manner as above. An outer layer can be formed on the emulsion particles constituting the emulsion.

When the outer layer is formed on the emulsion particles that make up the inner layer, the outer layer is formed after the polymerization reaction rate when producing the emulsion particles that make up the inner layer reaches 90% or more, preferably 95% or more. Emulsion polymerization of the monomer components is preferred from the viewpoint of forming a layer-separated structure of an inner layer and an outer layer within the emulsion particles.

Monomers used for the outer layer monomer component include monofunctional monomers and polyfunctional monomers, similar to the monomer component used for the inner layer monomer component. The monofunctional monomer and the polyfunctional monomer may be used alone or in combination. Although it is conceivable to use only a polyfunctional monomer as the monomer component for the outer layer, usually only a monofunctional monomer or a combination of a monofunctional monomer and a polyfunctional monomer are used.

As a representative example of the monofunctional monomer, a radically polymerizable monomer such as an ethylenically unsaturated monomer used in the monomer component for the inner layer can be exemplified. Examples of ethylenically unsaturated monomers include alkyl (meth)acrylates, hydroxyl group-containing (meth)acrylates, aralkyl (meth)acrylates, alkoxyalkyl (meth)acrylates, carboxyl group-containing ethylenically unsaturated monomers, and oxo group-containing ethylenic monomers. Unsaturated monomers, fluorine atom-containing ethylenically unsaturated monomers, nitrogen atom-containing ethylenically unsaturated monomers, styrene monomers, epoxy group-containing ethylenically unsaturated monomers, silane group-containing ethylenically unsaturated monomers, carbonyl group-containing ethylenically unsaturated monomers Examples include saturated monomers and ethylenically unsaturated monomers containing an aziridinyl group, but the present invention is not limited to these examples. These ethylenically unsaturated monomers may be used alone or in combination of two or more. Alkyl (meth)acrylate, hydroxyl group-containing (meth)acrylate, aralkyl (meth)acrylate, alkoxyalkyl (meth)acrylate, carboxyl group-containing ethylenically unsaturated monomer, oxo group-containing ethylenically unsaturated monomer, fluorine atom-containing ethylenically unsaturated monomer Saturated monomers, nitrogen atom-containing ethylenically unsaturated monomers, styrene monomers, epoxy group-containing ethylenically unsaturated monomers, silane group-containing ethylenically unsaturated monomers, carbonyl group-containing ethylenically unsaturated monomers, and aziridinyl group-containing ethylenically unsaturated monomers Examples of monomers include those used for the monomer component for the inner layer. These monomers may be used alone or in combination of two or more.

Among the carboxyl group-containing ethylenically unsaturated 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 of emulsion particles. Among styrenic monomers, styrene, alkylkylstyrene whose alkyl group has 1 to 4 carbon atoms, and alkoxy group Alkoxystyrene having 1 to 4 carbon atoms is preferred, alkylkylstyrene having styrene and an alkyl group having 1 to 4 carbon atoms is more preferred, and alkylkylstyrene having styrene and an alkyl group having 1 or 2 carbon atoms. is more preferred, and styrene is even more preferred.

As the polyfunctional monomer, the same ones as those used for the monomer component for the inner layer can be exemplified.

From the viewpoint of imparting ultraviolet stability or ultraviolet absorption to the emulsion particles, the monomer component for the outer layer preferably contains an ultraviolet stable monomer, an ultraviolet absorbing monomer, etc. within a range that does not impede the purpose of the present invention. . Examples of the ultraviolet stable monomer and the ultraviolet absorbing monomer include those used for the monomer component for the inner layer.

The monomer components for the outer layer include alkyl (meth)acrylates, styrene monomers, hydroxyl group-containing (meth)acrylates, and UV-stable monomers to improve flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is more preferable to contain an alkyl (meth)acrylate whose alkyl group has 1 to 8 carbon atoms, a styrenic monomer, and a UV-stable monomer.

The content of alkyl (meth)acrylate in the monomer component for the outer layer is preferably 40 to 97% by mass, more preferably 40 to 97% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is 45 to 95% by mass. The content of alkyl (meth)acrylate, preferably methyl (meth)acrylate, in which the alkyl group has 1 to 3 carbon atoms in the monomer component for the outer layer is determined based on flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. From the viewpoint of improving scratch resistance, the content is preferably 5 to 50% by mass, more preferably 10 to 45% by mass. The content of alkyl (meth)acrylate whose alkyl group has 4 to 8 carbon atoms in the monomer component for the outer layer is determined from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is preferably 30 to 75% by weight, more preferably 35 to 70% by weight.

The content of the styrene monomer in the monomer component for the outer layer is preferably 0 to 50% by mass, more preferably 0 to 50% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is 45% by mass.

The content of the styrene monomer in the monomer component for the outer layer is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. It is 97% by mass.

The content of the hydroxyl group-containing (meth)acrylate in the monomer component for the outer layer is preferably 0.5 to 10% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the base material, and scratch resistance. More preferably, it is 1 to 5% by mass.

The content of the ultraviolet stable monomer in the monomer component for the outer layer is preferably 0.5 to 10% by mass, more preferably 0.5 to 10% by mass, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. is 1 to 5% by mass.

The method of emulsion polymerization of the monomer component for the outer layer, the polymerization reaction conditions, etc. may be the same as the method of emulsion polymerization, the polymerization reaction conditions, etc. of the monomer component for the inner layer.

By emulsion polymerizing the monomer component for the outer layer in the resin emulsion containing the emulsion particles constituting the inner layer as described above, a resin emulsion containing the emulsion particles having an inner layer and an outer layer can be obtained. Note that the polymer constituting the outer layer may have a crosslinked structure if necessary.

The glass transition temperature of the polymer constituting the outer layer is 10°C or lower, preferably 5°C or lower, and more preferably 0°C from the viewpoint of improving flexibility, blocking resistance, adhesion to the base material, and scratch resistance. The lower limit of the glass transition temperature is preferably -50°C or higher, more preferably -45°C from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. above, more preferably -40°C or above. The glass transition temperature of the polymer constituting the outer layer can be easily adjusted by adjusting the type and amount of the monomer used in the monomer component for the outer layer.

The difference between the glass transition temperature of the polymer in the inner layer and the glass transition temperature of the polymer in the outer layer is preferably 50 to 150°C from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. , more preferably 60 to 145°C, still more preferably 70 to 140°C, even more preferably 80 to 135°C.

The glass transition temperature of all the polymers constituting the emulsion particles is preferably -30 to 45°C, more preferably -25 to 40°C, more preferably -20 to 35°C. The glass transition temperature of all the polymers constituting the emulsion particles can be easily adjusted by adjusting the types and amounts of monomers used in the inner layer monomer component and the outer layer monomer component.

The acid value of the entire resin layer of the emulsion particles is preferably 5 mgKOH/g or less, more preferably 3 mgKOH/g or less, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. More preferably it is 1 mgKOH/g or less, even more preferably 0.5 mgKOH/g or less, particularly preferably 0.3 mgKOH/g or less. Note that the acid value is mainly derived from the carboxyl group that the emulsion particles have, and means the amount (mg) of potassium hydroxide required when neutralizing 1 g of the emulsion particles with potassium hydroxide. The acid value can be calculated based on the amount of acid group-containing ethylenically unsaturated monomers contained in all monomer components used as raw materials for emulsion particles.

The emulsion particles contained in the resin emulsion may have two resin layers, an inner layer and an outer layer, prepared by two-stage emulsion polymerization. A resin layer other than the inner layer and outer layer may be formed, such as an intermediate layer between the inner layer and the outer layer, or a layer above the outer layer.

The number of resin layers that the emulsion particles have is two or more layers, preferably two or three layers, from the viewpoint of improving flexibility, blocking resistance, adhesion to the base material, and scratch resistance, More preferably, it has two layers. Note that the boundaries between the plurality of resin layers included in the emulsion particles do not necessarily have to be clear, and adjacent resin layers may be mixed with each other.

The mass ratio of the resin layer constituting the inner layer and the resin layer constituting the outer layer (resin layer constituting the inner layer/resin layer constituting the outer layer) is determined based on flexibility, blocking resistance, From the viewpoint of improving adhesion to the substrate and scratch resistance, 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 it is 40/60 to 60/40.

The weight average molecular weight of all the polymers contained in the emulsion particles is preferably 100,000 or more, more preferably 300,000 or more, from the viewpoint of improving flexibility, blocking resistance, adhesion to the substrate, and scratch resistance. Above, more preferably 400,000 or more, still more preferably 500,000 or more. The upper limit of the weight average molecular weight of the polymer is not particularly limited because it is difficult to measure the weight average molecular weight when it has a crosslinked structure, but when it does not have a crosslinked structure, it is determined by flexibility and anti-blocking. From the viewpoint of improving the properties, adhesion to the substrate, and scratch resistance, it is preferably 4,000,000 or less.

In the present invention, the weight average molecular weight of all polymers contained in emulsion particles is determined by gel permeation chromatography equipped with an RI detector [manufactured by Tosoh Corporation, product number: HLC-8120GPC, column: TSKgel G-5000HXL] and TSKgel GMHXL-L in series, developing solvent: tetrahydrofuran (THF)] and standard polystyrene F-450 and A-5000 manufactured by Tosoh Corporation. , A-1000 and A-300.

The resin emulsion obtained as described above can be used as the resin emulsion for aqueous ink of the present invention.

The average particle diameter of the emulsion particles is preferably 50 nm or more, more preferably 100 nm or more, and even more preferably 200 nm or more, from the viewpoint of improving the mechanical stability of the emulsion particles themselves, and has excellent transparency, water resistance, and freezing properties. From the viewpoint of forming a coating film with excellent stability against repeated melting, the thickness is preferably 400 nm or less, more preferably 350 nm or less, and even more preferably 300 nm or less. In addition, in the present invention, the average particle diameter of the emulsion particles is obtained by the cumulant method when measured using a particle size distribution analyzer using a dynamic light scattering method [manufactured by Otsuka Electronics Co., Ltd., product number: FPAR-1000]. This is the value.

The non-volatile content of the resin emulsion for water-based ink is preferably 10% by mass or more, more preferably 20% by mass or more, from the viewpoint of improving the productivity of the water-based ink, and from the viewpoint of improving the handleability of the water-based ink, it is preferably is 70% by mass or less, more preferably 60% by mass or less. In the present invention, the non-volatile content of the resin emulsion for water-based ink is calculated by weighing 1 g of the resin emulsion for water-based ink, drying it in a hot air dryer at a temperature of 120°C for 1 hour, and taking the obtained dry residue as the non-volatile content, and formula:
[Nonvolatile content (mass%) of resin emulsion for water-based ink]
= ([mass of dry residue] ÷ [1 g of resin emulsion for water-based ink]) x 100
This is the value calculated based on.

The minimum film-forming temperature of the resin emulsion for water-based ink is preferably 60°C or lower, more preferably 50°C or lower, and even more preferably 40°C or lower, from the viewpoint of improving the adhesion to the base material, and the water resistance and blocking resistance. From the viewpoint of improving properties, the temperature is preferably -5°C or higher, more preferably 5°C or higher, and still more preferably 10°C or higher. The minimum film-forming temperature of the resin emulsion for water-based ink is determined by applying the emulsion to a thickness of 0.2 mm using an applicator on a glass plate placed on a thermal gradient tester, drying it, and applying it to a glass plate placed on a thermal gradient tester to prevent cracks. It means the temperature at which it occurs.

The water-based ink of the present invention contains a resin emulsion for water-based ink and a colorant. Examples of the hue of the colorant include achromatic colors such as white, black, and gray, and chromatic colors such as yellow, magenta, cyan, blue, red, orange, and green; however, the present invention is limited only to such examples. It is not something that will be done.

Colorants include pigments and dyes. Among these, pigments are preferred because they have excellent weather resistance. When using a pigment, the pigment 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, and these may be used alone or in combination.

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, and iminoisoindoline. Pigments, iminoisoindolinone pigments, quinacridone pigments such as quinacridone red and quinacridone violet, flavanthrone pigments, indanthrone pigments, anthrapyrimidine pigments, carbazole pigments, monoarylide yellow, diarylide yellow, benzimidazolone yellow, trill orange , naphthol orange, quinophthalone pigments, etc., but the present invention is not limited to these examples. These organic pigments may be used alone or in combination of two or more. Preferred organic pigments include, for example, C.I. I. pigment yellow, C. I. pigment red, C. I. pigment orange, C. I. pigment violet, C. I. pigment blue, C. I. Pigment green, etc.

Examples of inorganic pigments include titanium dioxide, antimony trioxide, zinc white, lithopone, lead white, red iron oxide, black iron oxide, iron oxide, chromium oxide green, carbon black, yellow lead, molybdenum red, and ferrocyanide. Pigments with flat shapes such as diiron (Prussian blue), ultramarine, lead chromate, mica, clay, aluminum powder, talc, aluminum silicate, calcium carbonate, magnesium hydroxide, aluminum hydroxide , barium sulfate, magnesium carbonate, and other extender pigments, but the present invention is not limited to these examples. These inorganic pigments may be used alone or in combination of two or more.

The average particle diameter of the pigment is preferably 30 nm or more, more preferably 50 nm or more, from the viewpoint of improving dispersion stability in aqueous ink, and when used as an inkjet aqueous ink, prevents nozzle clogging and improves the nozzle. From the viewpoint of improving the ejection stability of aqueous ink from the head, the thickness is preferably 200 nm or less, more preferably 150 nm or less. The average particle diameter of the pigment means the volume average particle diameter measured using a laser diffraction scattering particle size distribution analyzer [manufactured by Beckman Coulter, product number: LS13320].

Examples of dyes include C.I. I. Solvent Black, C. I. Solvent Red, C. I. Solvent Yellow, C. I. Solvent Blue, C. I. Solvent Green, C. I. Solvent Orange, C. I. Examples include solvent violet, but the present invention is not limited to such examples.

The amount of colorant per 100 parts by mass of non-volatile content of the resin emulsion for water-based ink used in the water-based ink is preferably 50 parts by mass or more, more preferably is 100 parts by mass or more, and from the viewpoint of forming a uniform coating film, is preferably 300 parts by mass or less, more preferably 200 parts by mass or less.

Note that from the viewpoint of improving the dispersibility of the colorant in the aqueous ink, the aqueous ink may contain water or a water-soluble organic solvent. Examples of water-soluble organic solvents include polyhydric alcohols such as diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, 1,3-propanediol, glycerin, dipropylene glycol, and tripropylene glycol; ethylene glycol monomethyl ether, ethylene Ethylene glycol monoethers such as glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol mono Diethylene glycol monoethers such as isopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol monobutyl ether, propylene glycol monoisobutyl ether Propylene glycol monoethers such as polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monoisopropyl ether, polyethylene glycol monobutyl ether, polyethylene glycol monoisobutyl ether; polypropylene glycol monomethyl Examples include polypropylene glycol monoethers such as ether, polypropylene glycol monoethyl ether, polypropylene glycol monopropyl ether, polypropylene glycol monoisopropyl ether, polypropylene glycol monobutyl ether, and polypropylene glycol monoisobutyl ether, but the present invention is limited to such examples only. It is not limited. These water-soluble organic solvents may be used alone or in combination of two or more. Among these water-soluble organic solvents, diethylene glycol, triethylene glycol, propylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether and diethylene glycol monoisobutyl ether are preferred.

The amount of water-soluble organic solvent varies depending on the type and amount of colorant contained in the water-based ink, so it cannot be determined unconditionally. It is preferable to decide as appropriate.

The water-based ink of the present invention contains the resin emulsion for water-based ink and a colorant, but within a range that does not impede the object of the present invention, resin emulsions other than the resin emulsion for water-based ink, water-soluble resins, A resin such as a water-dispersible resin may also be included. In addition, the aqueous ink of the present invention may include, for example, a surfactant, a film forming aid, an ultraviolet absorber, an ultraviolet inhibitor, a filler, a leveling agent, a dispersant, and an additive, within a range that does not impede the purpose of the present invention. Additives such as adhesives, wetting agents, plasticizers, stabilizers, and antioxidants may be included in appropriate amounts.

The nonvolatile content of the aqueous ink of the present invention is preferably 10% by mass or more, more preferably 20% by mass or more from the viewpoint of improving the productivity of the aqueous ink, and from the viewpoint of improving the handleability of the aqueous ink. is 80% by mass or less, more preferably 70% by mass or less. In the present invention, the nonvolatile content of the aqueous ink of the present invention is a value measured in the same manner as the nonvolatile content of the resin emulsion for aqueous ink.

In the present invention, prints or images having a predetermined pattern can be formed by ejecting the aqueous ink of the present invention onto a recording medium in a predetermined pattern using, for example, an inkjet recording device.

Examples of recording media include paper, paper laminated with resin films such as polyethylene, polypropylene, and polystyrene (coated paper, etc.), metal plates such as aluminum, zinc, and copper, cellulose, polyethylene terephthalate, polyethylene, polystyrene, etc. Examples include resin films such as polypropylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, and acrylic resin, paper with a metal coating, and resin films with a metal coating, but the present invention is not limited to these examples. .

Further, in the present invention, for example, the aqueous ink of the present invention can be printed onto textile products such as fabrics made of natural fibers such as cotton, synthetic fibers such as polyester fibers, acrylic fibers, and polyamide fibers using an inkjet recording device or the like. By doing so, a desired design can be imparted to the textile product.

The aqueous ink of the present invention obtained as described above has comprehensively excellent flexibility, anti-blocking properties, adhesion to substrates, and scratch resistance. It can be suitably used as inks such as commercial inks, offset printing inks, lithographic printing inks, gravure printing inks, and screen printing inks, especially as aqueous inkjet inks.

Next, the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example 1
767 g 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. A pre-emulsion for first stage dropping consisting of 169 g of deionized water, 70 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 17 g of 2-ethylhexyl acrylate, and 483 g of styrene was placed in a dropping funnel. 30g of the mixture, which is 2% by mass of the total amount of all monomer components, was added into a flask, the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. . Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 70 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-20], and 2- 236 g of ethylhexyl acrylate, 224 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 10 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300 mesh (JIS mesh, hereinafter the same) wire mesh to obtain a resin emulsion for aqueous ink.

In each Example and each Comparative Example, the pH is a value measured at 25° C. using a pH meter [manufactured by Horiba, Ltd., product number: F-23].

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 200 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 620,000. The glass transition temperature of the inner layer of the emulsion particles is 90°C, the glass transition temperature of the outer layer is -5°C, the difference in glass transition temperature between the inner layer and the outer layer is 95°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 35°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 2
767 g 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 a dropping funnel were placed 169 g of deionized water, 70 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 25 g of 2-ethylhexyl acrylate, 270 g of methyl methacrylate, 200 g of styrene, and 5 g of acrylic acid. Prepare a pre-emulsion for the first drop, add 30 g of it, which is 2% by mass of the total amount of all monomer components, into a flask, heat it up to 80°C while gently blowing nitrogen gas, and add 30 g of a 5% ammonium persulfate aqueous solution. was added to start polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 70 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-20], and 2- 194 g of ethylhexyl acrylate, 66 g of methyl methacrylate, 200 g of styrene, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product A pre-emulsion for second stage dropping consisting of 20 g of Adekastab LA-87 and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over a period of 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 230 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 600,000. The glass transition temperature of the inner layer of the emulsion particles is 87°C, the glass transition temperature of the outer layer is 8°C, the difference between the glass transition temperatures of the inner layer and the outer layer is 79°C, and the glass transition temperature of the entire resin layer of the emulsion particles is was 40°C. Further, the acid value of the entire resin layer of the emulsion particles was 4 mgKOH/g.

Example 3
767 g 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. A pre-emulsion for first stage dropping consisting of 169 g of deionized water, 100 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-10], 17 g of 2-ethylhexyl acrylate, and 483 g of styrene was placed in a dropping funnel. 30g of the mixture, which is 2% by mass of the total amount of all monomer components, was added into a flask, the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. . Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 100 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-10], and 2- 236 g of ethylhexyl acrylate, 224 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 20 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 200 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 620,000. The glass transition temperature of the inner layer of the emulsion particles is 90°C, the glass transition temperature of the outer layer is -5°C, the difference in glass transition temperature between the inner layer and the outer layer is 95°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 35°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 4
767 g 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. A pre-emulsion for the first stage dropping consisting of 169 g of deionized water, 50 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-10], 17 g of 2-ethylhexyl acrylate, and 483 g of styrene was placed in a dropping funnel. 30g of the mixture, which is 2% by mass of the total amount of all monomer components, was added into a flask, the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. . Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the completion of the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 50 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-10], and 2- 236 g of ethylhexyl acrylate, 224 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 20 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 250 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 620,000. The glass transition temperature of the inner layer of the emulsion particles is 90°C, the glass transition temperature of the outer layer is -5°C, the difference in glass transition temperature between the inner layer and the outer layer is 95°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 35°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 5
767 g 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. A pre-emulsion for the first stage dropping consisting of 169 g of deionized water, 30 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-10], 17 g of 2-ethylhexyl acrylate, and 483 g of styrene was placed in a dropping funnel. 30g of the mixture, which is 2% by mass of the total amount of all monomer components, was added into a flask, the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. . Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 30 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-10], and 2- 236 g of ethylhexyl acrylate, 224 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 20 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 280 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 620,000. The glass transition temperature of the inner layer of the emulsion particles is 90°C, the glass transition temperature of the outer layer is -5°C, the difference in glass transition temperature between the inner layer and the outer layer is 95°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 35°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 6
767 g 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. A pre-emulsion for first stage dropping was prepared in a dropping funnel, consisting of 169 g of deionized water, 30 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-30], 150 g of methyl methacrylate, and 350 g of styrene. Of these, 30 g, which is 2% by mass of the total amount of all monomer components, was added into the flask, and the temperature was raised to 80° C. while slowly blowing nitrogen gas, and 30 g of 5% ammonium persulfate aqueous solution was added to start polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 30 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-30], and 2- 287 g of ethylhexyl acrylate, 188 g of methyl methacrylate, 5 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 20 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 300 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 600,000. The glass transition temperature of the inner layer of the emulsion particles is 101°C, the glass transition temperature of the outer layer is -20°C, the difference in glass transition temperature between the inner layer and the outer layer is 121°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 30°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 7
767 g 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. A pre-emulsion for the first stage dropping consisting of 68 g of deionized water, 28 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 7 g of 2-ethylhexyl acrylate, and 193 g of styrene was placed in a dropping funnel. 30g of the mixture, which is 2% by mass of the total amount of all monomer components, was added into a flask, the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. . Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the completion of the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 271 g of deionized water, 112 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: Adekaria Soap SR-20], and 2- 550 g of ethylhexyl acrylate, 200 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 30 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 240 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 580,000. The glass transition temperature of the inner layer of the emulsion particles is 89°C, the glass transition temperature of the outer layer is -36°C, the difference between the glass transition temperatures of the inner layer and the outer layer is 125°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was -18°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 8
767 g 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. A pre-emulsion for the first stage dropping consisting of 68 g of deionized water, 28 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 7 g of 2-ethylhexyl acrylate, and 193 g of styrene was placed in a dropping funnel. 30g of the mixture, which is 2% by mass of the total amount of all monomer components, was added into a flask, the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. . Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the completion of the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 271 g of deionized water, 112 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: Adekaria Soap SR-20], and 2- 450 g of ethylhexyl acrylate, 300 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: ADEKA STAB LA-87] 30 g of a second stage dropping pre-emulsion and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 240 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 565,000. The glass transition temperature of the inner layer of the emulsion particles is 89°C, the glass transition temperature of the outer layer is -19°C, the difference between the glass transition temperatures of the inner layer and the outer layer is 108°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was -3°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Example 9
767 g 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. A pre-emulsion for the first stage dropping consisting of 169 g of deionized water, 50 g of a 25% aqueous solution of an emulsifier [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 17 g of 2-ethylhexyl acrylate, and 483 g of styrene was placed in a dropping funnel. of which 30g, which is 2% by mass of the total amount of all monomer components, was added into a flask, and the temperature was raised to 80°C while slowly blowing nitrogen gas, and 30g of 5% ammonium persulfate aqueous solution was added to start polymerization. did. Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the addition, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 50 g of a 25% aqueous solution of an emulsifier [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], and 2 - 236 g of ethylhexyl acrylate, 224 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and as a UV-stable monomer 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., product name: A pre-emulsion for second stage dropping consisting of 20 g of Adekastab LA-87 and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 250 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 620,000. The glass transition temperature of the inner layer of the emulsion particles is 90°C, the glass transition temperature of the outer layer is -5°C, the difference in glass transition temperature between the inner layer and the outer layer is 95°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 35°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Comparative example 1
767 g 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. Into a dropping funnel, 169 g of deionized water, 50 g of a 25% aqueous solution of emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 236 g of 2-ethylhexyl acrylate, 224 g of methyl methacrylate, 20 g of 2-hydroxyethyl methacrylate, and ultraviolet light. A pre-emulsion for the first drop was prepared containing 20 g of 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., trade name: ADEKA STAB LA-87] as a stable monomer. Then, 30 g of the flask, which corresponds to 2% by mass of the total amount of all monomer components, was added into the flask, the temperature was raised to 80° C. while slowly blowing nitrogen gas, and 30 g of a 5% ammonium persulfate aqueous solution was added to start polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 70 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-20], and 2- A pre-emulsion for second dropping consisting of 17 g of ethylhexyl acrylate and 483 g of styrene and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 250 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 530,000. The glass transition temperature of the inner layer of the emulsion particles is -5°C, the glass transition temperature of the outer layer is 90°C, the difference between the glass transition temperatures of the inner layer and the outer layer is -95°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The transition temperature was 35°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Comparative example 2
767 g 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. A first stage consisting of 169 g of deionized water, 70 g of a 25% aqueous solution of emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 130 g of 2-ethylhexyl acrylate, 185 g of methyl methacrylate, and 185 g of styrene was dropped into a dropping funnel. Prepare a pre-emulsion for use, add 30 g of it, which is 2% by mass of the total amount of all monomer components, into a flask, raise the temperature to 80 ° C. while slowly blowing nitrogen gas, and add 30 g of a 5% ammonium persulfate aqueous solution, Polymerization started. Thereafter, the remainder of the pre-emulsion for dropping and 20 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropping, the contents of the flask were maintained at 80°C for 60 minutes, and then 169 g of deionized water, 70 g of a 25% aqueous solution of an emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA REA SOAP SR-20], and 2- 130 g of ethylhexyl acrylate, 165 g of methyl methacrylate, 165 g of styrene, 20 g of 2-hydroxyethyl methacrylate, and 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine as a UV-stable monomer [manufactured by ADEKA Co., Ltd., product A pre-emulsion for second stage dropping consisting of 20 g of Adekastab LA-87 and 10 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over a period of 60 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a two-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 240 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 520,000. The glass transition temperature of the inner layer of the emulsion particles is 35°C, the glass transition temperature of the outer layer is 34°C, the difference between the glass transition temperatures of the inner layer and the outer layer is 1°C, and the glass transition temperature of the entire resin layer of the emulsion particles is The temperature was 34°C. Further, the acid value of the entire resin layer of the emulsion particles was less than 0.1 mgKOH/g.

Comparative example 3
747 g 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. Into a dropping funnel were 403 g of deionized water, 40 g of a 25% aqueous solution of emulsifier [manufactured by ADEKA Co., Ltd., trade name: ADEKA Reasap SR-20], 72 g of 2-ethylhexyl acrylate, 867 g of styrene, 51 g of acrylic acid, 2-hydroxyethyl methacrylate. A pre-emulsion for dropping was prepared consisting of 10 g of UV-stable monomer and 20 g of 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine [manufactured by ADEKA Co., Ltd., trade name: ADEKA STAB LA-87]. Then, 30 g of the flask, which corresponds to 2% by mass of the total amount of all monomer components, was added into the flask, the temperature was raised to 80° C. while slowly blowing nitrogen gas, and 30 g of a 5% ammonium persulfate aqueous solution was added to start polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 30 g of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

After the dropwise addition was completed, the contents of the flask were maintained at 80° C. for 60 minutes, and the pH was adjusted to 9 by adding 25% aqueous ammonia to complete the polymerization reaction. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain a resin emulsion for aqueous ink.

The content of nonvolatile matter in the obtained resin emulsion for water-based ink is 45% by mass, and the emulsion particles contained in the resin emulsion for water-based ink have a one-layer structure, and the average particle diameter of the emulsion particles is 45% by mass. was 60 nm, and the weight average molecular weight of the polymer constituting the emulsion particles was 380,000. The glass transition temperature of the emulsion particles was 80°C. Further, the acid value of the entire resin layer of the emulsion particles was 40 mgKOH/g.

Next, water-based inks were prepared based on the following method using the resin emulsions for water-based inks obtained in each Example or each Comparative Example.

(1) Preparation of water-based ink While stirring 22 g of the resin emulsion for water-based ink obtained in each Example or each Comparative Example at a rotation speed of 1000 min ^-1 with a homodisper, 23 g of white paste, 10 g of propylene glycol, diethylene glycol monoisopropyl 15 g of ether, 0.4 g of polyether-modified silicone surfactant [manufactured by Shin-Etsu Chemical Co., Ltd., product number: KF-6011] and ion-exchanged water were added so that the total amount was 100 g, and the mixture was further stirred for 30 minutes. Thereafter, a water-based ink was obtained by filtration with a filter having an average pore size of 3 μm (manufactured by Advantech Co., Ltd., product number: MCP-3-C10S).

The white paste contained 428 g of deionized water, 50 g of dispersant [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Discoat N-14], 60 g of propylene glycol, titanium oxide [manufactured by Ishihara Sangyo Co., Ltd., product number]. :CR-95, average particle size: 0.28 μm] and 200 g of glass beads (diameter: 1 mm) as a dispersion medium were dispersed with a homodisper at a rotation speed of 3000 min ^-1 for 120 minutes, and then filtered through a 300 mesh wire mesh. It was prepared by:

(2) Production of inkjet printed matter In air at a temperature of 25 ± 1°C and relative humidity of 30 ± 5%, a print evaluation device [Kyocera Corporation, product number: KJ4B-YH06WST-STDV] equipped with an inkjet print head [manufactured by Kyocera Corporation, product number: KJ4B-YH06WST-STDV] ) manufactured by Genesis] was filled with water-based ink.

Next, in the print evaluation device, the head voltage was set to 26 V, the frequency was set to 4 kHz, the ejected droplet volume was set to 12 pL (picoliter), the head temperature was set to 32°C, the resolution was set to 600 dpi, and the negative pressure was set to -4.0 kPa. It was set to A corona-treated polyester film [manufactured by Futamura Kagaku Co., Ltd., trade name: Taiko Polyester Film FE2001] was used as a recording medium, and it was fixed on a conveyor table so that the longitudinal direction of the corona-treated polyester film and the conveyance direction were the same direction. did. The printing command is transferred to the printing evaluation device, and a solid image is printed using an inkjet recording method using water-based ink on a corona-treated polyester film at a printing rate of 100% (12 pL, 600 x 600 dpi). A test sheet was obtained by drying the corona-treated polyester film for 10 seconds.

The following physical properties were investigated using the aqueous ink obtained in each Example or each Comparative Example and the test sheet obtained above. The results are shown in Table 1.

(1) Flexibility After leaving the test sheet in an atmosphere of -10°C, -5°C or 5°C for 30 minutes, examine the folds when folding the test sheet in half in the atmosphere. The flexibility was visually observed and evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
5: No abnormality is observed in the folds of the test sheet in an atmosphere of -10°C.
4: No abnormalities are observed in the folds of the test sheet in an atmosphere of -5°C, but slight cracks are observed in the folds of the test sheet in an atmosphere of -10°C.
3: No abnormalities are observed in the folds of the test sheet in an atmosphere of -5°C, but clear cracks are observed in the folds of the test sheet in an atmosphere of -10°C.
2: No abnormalities are observed in the folds of the test sheet in an atmosphere of 5°C, but slight cracks are observed in the folds of the test sheet in an atmosphere of -5°C.
1: No abnormalities are observed in the folds of the test sheet in an atmosphere of 5°C, but clear cracks are observed in the folds of the test sheet in an atmosphere of -5°C.
Cracks are observed at the folds of the test sheet in an atmosphere of 0:5°C.

(2) Blocking resistance A polyester film that has not been subjected to corona treatment is placed on the printed surface of the test sheet, and a load of 2 N/cm ² is applied on top of the polyester film in air at 25°C for 1 hour. The polyester film was quickly peeled off, the resistance felt at that time was observed, and the blocking resistance was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
5: No resistance is felt when the polyester film is peeled off.
4: Only a slight resistance is felt when the polyester film is peeled off.
3: Only a little resistance is felt when the polyester film is peeled off.
2: Resistance is clearly felt when the polyester film is peeled off.
1: Strong resistance is felt when the polyester film is peeled off.
0: Very strong resistance is felt when the polyester film is peeled off.

(3) Adhesion The printed image on the test sheet was rubbed with a fingernail, and the adhesion to the substrate was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
5: Even if the printed image is rubbed with a fingernail, the image does not come off at all.
4: When the printed image is rubbed with a fingernail, the image peels off only slightly.
3: When the printed image is rubbed with a fingernail, the image peels off slightly.
2: If you rub the printed image with your fingernail, the image will peel off a little.
1: When the printed image is rubbed with a fingernail, the image clearly peels off.
0: When the printed image is rubbed with a fingernail, the image is easily peeled off.

(3) Scratch resistance The printed image of the test sheet was subjected to a pencil hardness test in accordance with JIS K5600, and the scratch resistance was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
5: Pencil hardness is F or higher 4: Pencil hardness is HB
3: Pencil hardness is B
2: Pencil hardness is 2B
1: Pencil hardness is 3B
0: Pencil hardness is 4B or less

(4) Comprehensive evaluation The sum of the scores for each test item was used as an index for the comprehensive evaluation.

From the results shown in Table 1, the water-based inks obtained in each example had better flexibility, blocking resistance, adhesion, and scratch resistance than the water-based inks obtained in each comparative example. It can be seen that the overall performance is excellent.

The water-based ink of the present invention has excellent overall flexibility, blocking resistance, adhesion, and scratch resistance, so it can be applied to paper, resin sheets or films, metal plates, wood plates, leather, etc. Industries such as printing ink that forms desired information such as characters, patterns, colors, etc. on base materials made of materials by inkjet printing, flexographic printing, offset printing, lithographic printing, gravure printing, screen printing, ink ribbon, etc. It can be suitably used for ink for commercial use.

Claims (13)

A resin emulsion for an aqueous ink containing emulsion particles having an inner layer and an outer layer as resin layers of the emulsion particles, wherein a polymer constituting the inner layer has a glass transition temperature of 80°C or higher, and a polymer constituting the outer layer has a glass transition temperature. A resin emulsion for an aqueous ink, characterized in that the transition temperature is 10° C. or less, and the acid value of the entire resin layer of the emulsion particles is 5 mgKOH/g or less . The resin emulsion for an aqueous ink according to claim 1, wherein the content of the carboxyl group-containing ethylenically unsaturated monomer in the inner layer monomer component used when forming the inner layer is 5% by mass or less. Aqueous according to claim 1 or 2, wherein the content of alkyl (meth)acrylate whose alkyl group has 1 to 3 carbon atoms in the outer layer monomer component used in forming the outer layer is 5 to 50% by mass. Resin emulsion for ink. The resin emulsion for an aqueous ink according to any one of claims 1 to 3, wherein the content of hydroxyl group-containing (meth)acrylate in the outer layer monomer component used in forming the outer layer is 0.5 to 10% by mass. The resin emulsion for a water-based ink according to any one of claims 1 to 4, wherein the content of the ultraviolet stable monomer in the outer layer monomer component used in forming the outer layer is 0.5 to 10% by mass. A method for producing a resin emulsion for an aqueous ink containing emulsion particles having an inner layer and an outer layer as resin layers of the emulsion particles , the emulsion particles constituting the inner layer having a polymer glass transition temperature of 80° C. or higher. After that, when forming an outer layer in which the glass transition temperature of the polymer is 10° C. or less on the emulsion particles constituting the inner layer, the acid value of the entire resin layer of the emulsion particles is adjusted to 5 mgKOH/g or less. A method for producing a resin emulsion for water-based ink. An aqueous ink comprising the resin emulsion for an aqueous ink according to any one of claims 1 to 5 and a colorant . The aqueous ink according to claim 7, wherein the amount of the colorant per 100 parts by mass of nonvolatile content of the resin emulsion for aqueous ink is 50 parts by mass or more and 300 parts by mass or less. The water-based ink contains at least one water-soluble organic solvent selected from the group consisting of diethylene glycol, triethylene glycol, propylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, and diethylene glycol monoisobutyl ether. The aqueous ink according to claim 7 or 8, comprising: The aqueous ink according to any one of claims 7 to 9, wherein the aqueous ink has a nonvolatile content of 20% by mass or more and 80% by mass or less. The water-based ink according to any one of claims 7 to 10, wherein the water-based ink is an inkjet water-based ink. The water-based ink according to any one of claims 7 to 11, wherein the water-based ink is used for a recording medium, and the recording medium is a resin film. The aqueous ink according to any one of claims 7 to 11, wherein the aqueous ink is an aqueous ink used for textile products.