JP2015030799A - Binder resin composition for aqueous ink and aqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder composition for an aqueous ink, which develops good physical properties of a coating film (adhesiveness, wet friction resistance, wet blocking resistance, and low odor) under the conditions of low-temperature drying, as well as shows excellent storage stability, re-dissolving property and plate cleaning property of an ink, and to provide an aqueous ink composition containing the binder composition.SOLUTION: The binder resin composition for an aqueous ink comprises: a core-shell resin fine particle dispersion (B) having an acid value of 50 to 90 mgKOH/g prepared by polymerizing an ethylenically unsaturated monomer (b) in an aqueous medium in the presence of a water-soluble resin (A); and a resin fine particle dispersion (C) having an acid value of 0 to 30 mgKOH/g prepared by polymerizing an ethylenically unsaturated monomer (c) in an aqueous medium.

Description

The present invention relates to a binder resin composition for water-based ink and a water-based ink composition. More specifically, for non-polar film substrates, it exhibits excellent substrate adhesion, coating resistance, and water blocking resistance with low odor under low temperature drying, while ink storage stability, re-dissolvability, It is related with the binder composition for water-based inks which is excellent also in plate washability, and the water-based ink composition using the binder composition concerned.

The water-based ink composition is generally composed of a pigment, a pigment dispersion resin, water, a humectant component, and a binder resin. Among these, the binder resin is added for the purpose of improving the coating film resistance (water resistance, rubbing resistance, adhesion, scratch resistance, etc.) of printed matter, and achieves both excellent coating film properties, ink properties, and printability. Since it can be used, many resin fine particle dispersions are used. Such aqueous ink compositions have been developed mainly for paper, cardboard, and other base materials. However, in recent years, from the viewpoint of energy saving, low cost, and environmental load reduction, olefins can be used under low temperature drying conditions. For non-polar film base materials such as PET and PET, there is a demand for a function that exhibits excellent coating physical properties (base material adhesion and water friction resistance), and at the same time, development of a binder resin composition that can cope with it is also required. ing.

Patent Document 1 discloses a binder resin composition of an all-acrylic resin fine particle dispersion. However, this resin fine particle dispersion has a large number of coarse particles generated during synthesis and is extremely poor in compatibility with the pigment dispersion resin. Therefore, when this resin fine particle dispersion is used in ink, the film forming property is poor and the coating film resistance is greatly deteriorated. In addition, unlike permeable substrates such as paper, the drying property on the film substrate is poor, and therefore, deterioration of water-resistant blocking due to residual components and odor are problematic.

Patent Document 2 discloses a water-based ink composition containing a resin fine particle dispersion in which the shell component, the composition of the core component, the molecular weight, the ratio between the core component and the shell component, the particle diameter, the glass transition temperature, and the like are defined. However, these resin fine particle dispersions also have poor film-forming properties, and the coating film resistance is not sufficiently exhibited on the film substrate. In addition, water blocking resistance and odor problems have not been solved.

  Patent Document 3 discloses a resin fine particle dispersion into which a keto group or an aldehyde group is introduced. Certainly, by cross-linking the keto group and aldehyde group of the resin fine particle dispersion, it is possible to expect an improvement in adhesion to a nonpolar film substrate and abrasion resistance. However, like the above-mentioned resin fine particle dispersion, drying failure is liable to occur on the film substrate, and the unreacted cross-linking agent may elute and conversely reduce the coating film resistance. In addition, improvement in odor due to residual components cannot be expected.

Japanese Patent Laid-Open No. 02-263811 Japanese Patent Laid-Open No. 08-176486 Japanese Patent Laid-Open No. 08-113749

Excellent coating properties (base adhesion, water rub resistance, water blocking resistance, low odor) on non-polar film substrates under low temperature drying conditions, while ink storage stability, It aims at providing the binder resin composition for water-based inks which is excellent also in solubility and plate washability, and a water-based ink composition using the same.

That is, the present invention provides a core-shell resin fine particle dispersion having an acid value of 50 to 90 mgKOH / g obtained by polymerizing an ethylenically unsaturated monomer (b) in an aqueous medium in the presence of the water-soluble resin (A) ( B) and
The present invention relates to a binder resin composition for water-based inks comprising a resin fine particle dispersion (C) having an acid value of 0 to 30 mg KOH / g obtained by polymerizing an ethylenically unsaturated monomer (c) in an aqueous medium. .

Furthermore, the amount of the resin fine particle dispersion (D) is 25 to 75% by weight in a total of 100% by weight of the resin solid content of the binder composition for water-based inks. About.

The core-shell resin fine particle dispersion (B) has an average particle diameter of 45 to 90 nm and a glass transition temperature of -10 to 30 ° C.

The resin fine particle dispersion (C) has an average particle diameter of 80 to 200 nm and a glass transition temperature of -5 to 30 ° C.

Furthermore, the present invention relates to a water-based ink composition comprising a pigment (D), a pigment-dispersed resin (E), water, a hydrophilic solvent (F), and the binder resin composition for water-based ink.

The present invention relates to the above water-based ink composition, wherein the minimum film-forming temperature of the water-based ink composition is 0 ° C. or lower.

The present invention relates to the above water-based ink composition used for flexographic printing or gravure printing.

  According to the present invention, excellent film properties (substrate adhesion, water rub resistance, water blocking resistance, low odor) are exhibited on nonpolar film substrates under low temperature drying conditions, while ink storage It was possible to provide a water-based binder resin composition and a water-based ink composition that are excellent in stability, re-dissolvability, and plate washability.

First, the core-shell type resin fine particle dispersion (B) used in the present invention will be described.

The core-shell type resin fine particle dispersion (B) for water-based ink is prepared by using an ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble resin (A) obtained by polymerizing the ethylenically unsaturated monomer (a). (B) can be obtained by emulsion polymerization using a radical polymerization initiator. The manufacturing method of a core-shell type resin fine particle dispersion (B) will be specifically described. First, an aqueous medium, a basic compound, and a water-soluble resin (A) are charged into a reaction vessel, and dissolved by heating. Thereafter, a radical polymerization initiator is added while dropping the ethylenically unsaturated monomer (b) under a nitrogen atmosphere. Since the color of the solution in the reaction vessel turns pale after the reaction starts, the formation of particle nuclei can be confirmed. The target resin fine particle dispersion can be obtained by further reacting for several hours after the completion of dropping of the ethylenically unsaturated monomer. The ethylenically unsaturated monomer (b) may be added dropwise to the reaction vessel as it is, or may be added dropwise after an emulsion is prepared in advance with an aqueous medium. The water-soluble resin (A) acts as a protective colloid (shell component) in the aqueous medium and stabilizes the generated particle core (core component). Since the resin fine particle dispersion obtained by this method has a viscosity close to Newtonian, it is very excellent in printability. The water-soluble resin (A) used for synthesizing the resin fine particle dispersion is obtained by subjecting the ethylenically unsaturated monomer (a) to solution polymerization or bulk polymerization with a radical initiator, and then converting the carboxyl group in the resin to basic. It can be obtained by neutralizing with a compound.

The water-soluble resin (A) used when synthesizing the core-shell type resin fine particle dispersion (B) takes into consideration efficient adsorption to the particle core, dispersion stability, and compatibility with the pigment-dispersed resin in the ink. Among them, those having an aromatic skeleton and having a carboxyl group are preferable. These skeletons use aromatic ethylenically unsaturated monomer (a-1) and carboxyl group-containing ethylenically unsaturated monomer (a-2) as ethylenically unsaturated monomer (a). Can be introduced.

Examples of the aromatic ethylenically unsaturated monomer (a-1) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, benzyl acrylate, benzyl methacrylate, Examples include phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol acrylate, phenoxytetraethylene glycol methacrylate, phenoxyhexaethylene glycol acrylate, phenoxyhexaethylene glycol methacrylate, phenyl acrylate, and phenyl methacrylate.

Examples of the carboxyl group-containing ethylenically unsaturated monomer (a-2) include maleic acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or alkenyl monoesters thereof, hexahydrophthalic acid β- (meta ) Acryloxyethyl monoester, β- (meth) acryloxyethyl monoester succinic acid, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and the like.

As the ethylenically unsaturated monomer (a), in addition to the aromatic ethylenically unsaturated monomer (a-1) and carboxyl group-containing ethylenically unsaturated monomer (a-2) defined above, An ethylenically unsaturated monomer (a-3) copolymerizable with (a-1) and (a-2) can be used in combination.

As the copolymerizable ethylenically unsaturated monomer (a-3), for example,
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate Straight chain or branched alkyl group-containing ethylenically unsaturated monomers such as nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, etc. Mer;
Alicyclic alkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
Fluorinated alkyl group-containing ethylenically unsaturated monomers such as trifluoroethyl (meth) acrylate and heptadecafluorodecyl (meth) acrylate;
(Meth) acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl -(Meth) acrylamide, N, N-di (methoxymethyl) acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N, N-di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethylmeta Acrylamide, N, N-di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) methacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) meta Acrylic net N, N-di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) methacrylamide, N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, N, N-dimethyl Amide group-containing ethylenically unsaturated monomers such as acrylamide and N, N-diethylacrylamide;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl Hydroxyl group-containing ethylenically unsaturated monomers such as alcohol;
Polyethylene glycol mono (meth) acrylate (Nippon Yushi Co., Ltd., Bremer PE-90, 200, 350, 350G, AE-90, 200, 400, etc.) Polyethylene glycol / polypropylene glycol mono (meth) acrylate (Nippon Yushi Co., Ltd., Blemmer 50PEP-300, 70PEP-350, etc.), polyethylene oxide group-containing ethylenically unsaturated monomers such as methoxypolyethylene glycol mono (meth) acrylate (manufactured by NOF Corporation, BLEMMER PME-400, 550, 1000, 4000, etc.);
Etc.

As the radical initiator, a known oil-soluble polymerization initiator can be used. For example, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexanoate), organic peroxides such as tert-butylperoxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide;
2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1 Mention may be made of azobis compounds such as' -azobis-cyclohexane-1-carbonitrile.

Examples of basic compounds used as neutralizing agents include amines such as ammonia, trimethylamine, triethylamine, butylamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol, and morpholine;
Hydroxide salts such as potassium hydroxide and sodium hydroxide;
Etc.

The ethylenically unsaturated monomer (a) preferably contains 20 to 70% by weight of the aromatic ethylenically unsaturated monomer (a-1), more preferably 50%, based on the whole monomer. It is in the range of ˜70% by weight. If it is less than 20% by weight, the efficiency of adsorption to the particle nuclei is reduced, aggregates are likely to be generated, and the resin fine particle dispersion becomes unstable. Furthermore, compatibility with the pigment-dispersed resin also decreases, and as a result, the storage stability of the ink and the physical properties of the coating film (substrate adhesion, water friction resistance) are deteriorated. On the other hand, even when it exceeds 70% by weight, the dispersibility of the water-soluble resin (A) is lowered, so that aggregates are easily generated and the resin fine particle dispersion becomes unstable. As a result, the storage stability of the ink and the physical properties of the coating film (substrate adhesion, water friction) are adversely affected.

  The ethylenically unsaturated monomer (a) preferably contains 30 to 40% by weight of the carboxyl group-containing ethylenically unsaturated monomer (a-2) with respect to the whole monomer. If it is less than 30% by weight, the dispersibility of the water-soluble resin (A) is reduced, so that aggregates are likely to be generated, and the storage stability of the ink is deteriorated. In addition, redissolvability and plate cleaning properties are also deteriorated. Furthermore, since the film forming property is also deteriorated, the compatibility between the shell component and the core component is adversely affected, and the physical properties of the coating film (base material adhesion property, water friction property) become poor. On the other hand, when it exceeds 40% by weight, the physical properties of the coating film (substrate adhesion, water friction resistance, blocking resistance) are deteriorated due to the occurrence of poor drying in the coating film and the increase of the components eluted into water.

  Furthermore, it is preferable that the acid value of water-soluble resin (A) is 100-300 mgKOH / g. When the acid value of the water-soluble resin (A) is less than 100 mgKOH / g, the dispersion stability of the resin fine particle dispersion is lowered and the storage stability of the ink is deteriorated, or the compatibility between the shell component and the core portion is reduced. In some cases, the physical properties of the coating film (base material adhesion, water friction resistance) may be reduced. On the other hand, if it exceeds 300 mgKOH / g, the coating properties (base adhesion, water rub resistance, blocking resistance) will be adversely affected due to the occurrence of poor drying in the coating and the increase in the amount of components eluted into water. There is. The acid value referred to here is the number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of the resin.

Subsequently, the ethylenically unsaturated monomer (b) constituting the core component of the core-shell type resin fine particle dispersion (B) will be described.

Examples of the ethylenically unsaturated monomer (b) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, and phenoxy. Aromatic ethylenically unsaturated monomers such as ethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol acrylate, phenoxytetraethylene glycol methacrylate, phenoxyhexaethylene glycol acrylate, phenoxyhexaethylene glycol methacrylate, phenyl acrylate and phenyl methacrylate body;
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate Straight chain or branched alkyl group-containing ethylenically unsaturated monomers such as nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, etc. Mer;
Alicyclic alkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
Fluorinated alkyl group-containing ethylenically unsaturated monomers such as trifluoroethyl (meth) acrylate and heptadecafluorodecyl (meth) acrylate;
(Meth) acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl -(Meth) acrylamide, N, N-di (methoxymethyl) acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N, N-di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethylmeta Acrylamide, N, N-di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) methacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) meta Acrylic net N, N-di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) methacrylamide, N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, N, N-dimethyl Amide group-containing ethylenically unsaturated monomers such as acrylamide and N, N-diethylacrylamide;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl Hydroxyl group-containing ethylenically unsaturated monomers such as alcohol;
Allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, 1-butenyl (meth) acrylate, 2-butenyl (meth) acrylate, 3-butenyl (meth) acrylate, 1,3- Methyl-3-butenyl (meth) acrylate, 2-chloroallyl (meth) acrylate, 3-chloroallyl (meth) acrylate, o-allylphenyl (meth) acrylate, 2- (allyloxy) ethyl (meth) acrylate, allyl lactyl (meth) Acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, rosinyl (meth) acrylate, cinnamyl (meth) acrylate, diallyl maleate, diallyl itaconic acid, vinyl (meth) acrylate, vinyl crotonic acid Vinyl oleate, vinyl linolenate, 2- (2′-vinyloxyethoxy) ethyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene glycol (meth) acrylate, trimethylol Propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethyl Ethylenically unsaturated monomers having two or more ethylenically unsaturated groups such as propane triacrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, diallyl maleate;
Epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate;
Keto group-containing ethylenically unsaturated monomers such as diacetone (meth) acrylamide and acetoacetoxy (meth) acrylate;
γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxy Propyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane Alkoxysilyl group-containing ethylenically unsaturated monomers such as vinyltributoxysilane and vinylmethyldimethoxysilane;
Examples include, but are not limited to, methylol group-containing ethylenically unsaturated monomers such as N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, and alkyl etherified N-methylol (meth) acrylamide. Is not to be done. These can be used alone or in combination of two or more.

Among the ethylenically unsaturated monomers (b) mentioned above, the ethylenically unsaturated monomer (b) may contain the aromatic ethylenically unsaturated monomer (b-1). preferable. By containing the aromatic ethylenically unsaturated monomer (b-1) in the core component, the compatibility between the core component and the shell component is increased, resulting in a uniform coating film and improving the resistance of the ink coating film. effective.

The aromatic ethylenically unsaturated monomer (b-1) is preferably 15 to 40% by weight in 100% by weight of the ethylenically unsaturated monomer (b). If it is less than 15% by weight, the particle nucleation becomes unstable and adversely affects the particle size control, and the compatibility between the shell component and the core component deteriorates to form a heterogeneous coating film. (Base material adhesion, water friction resistance) may be deteriorated. On the other hand, when the content exceeds 40% by weight, the compatibility between the shell component and the core component is deteriorated, so that the physical properties of the coating film (base material adhesion, water friction resistance) may be deteriorated.

Further, the ethylenically unsaturated monomer (b) preferably contains a keto group-containing ethylenically unsaturated monomer (b-2). By containing the keto group-containing ethylenically unsaturated monomer (b-2), the keto group derived from the ethylenically unsaturated monomer reacts with the hydrazide compound in the ink composition, and the base material of the coating film It has the effect of further improving adhesion and water friction resistance.

In 100% by weight of the ethylenically unsaturated monomer (b), the keto group-containing ethylenically unsaturated monomer (b-2) is preferably 1 to 3% by weight. If it is less than 1% by weight, the effect of crosslinking may not be confirmed in the physical properties of the coating film. On the other hand, when it exceeds 3% by weight, the compatibility of the shell component and the core component is deteriorated, and on the contrary, the physical properties of the coating film may be adversely affected. In addition, re-dissolvability and plate cleaning properties may be adversely affected. Introduction of keto group-containing ethylenically unsaturated monomer that is optimal for the composition of the core-shell type resin particle dispersion of the present invention in order to achieve both excellent compatibility between the core component and shell component and the effect of keto-hydrazide crosslinking. The amount is optimally in the range of 1 to 3% by weight.

The amount of the water-soluble resin (A) used at the time of synthesizing the core-shell type resin fine particle dispersion (B) is 40 to 60 parts by weight with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomer (B). Is preferred. If it is less than 40 parts by weight, the particle nuclei become unstable during the synthesis of the resin fine particle dispersion, and aggregates are generated, which may adversely affect the storage stability of the ink. In addition, since the compatibility between the core portion and the shell portion is inhibited during film formation, physical properties of the coating film (base material adhesion, water friction resistance) may be deteriorated. On the other hand, when the amount exceeds 60 parts by weight, poor drying is likely to occur and the amount of components eluted into water increases, so that the physical properties of the coating film (substrate adhesion, water friction resistance, water blocking resistance) are significantly reduced. There is.

The average particle diameter of the core-shell type resin fine particle dispersion (B) is preferably in the range of 45 to 90 nm. If the average particle size is less than 45 nm, the dispersion stability of the resin fine particle dispersion in the ink composition may be lowered, and the storage stability, re-dissolvability, and plate cleaning properties of the ink may be adversely affected. On the other hand, if it exceeds 90 nm, the film-forming property at the time of drying is lowered, and the physical properties of the coating film (base material adhesion, water friction resistance, water blocking resistance) may be deteriorated. The average particle size referred to here is a volume average particle size measured by a dynamic light scattering method in which the water dilution of the resin fine particle water dispersion (B) is irradiated with laser light and the Brownian motion of the particles is detected from the scattered light. The value of the diameter.

The acid value of the core-shell resin fine particle dispersion (B) is preferably in the range of 50 to 90 mgKOH / g. When the acid value is less than 60 mgKOH / g, compatibility with the resin fine particle dispersion (B) is inhibited during film formation, and the physical properties of the coating film (base material adhesion, water friction resistance) deteriorate. On the other hand, when the acid value exceeds 90 mgKOH / g, poor drying occurs and the remaining components increase, so the physical properties of the coating (base material adhesion, water rub resistance, water blocking resistance) are greatly reduced and after drying. The odor will also get worse.

The glass transition temperature (Tg) of the core-shell resin fine particle dispersion (B) is preferably in the range of −10 to 30 ° C. When the glass temperature is less than −10 ° C., the coating film strength is lowered, and the coating film properties (substrate adhesion, water friction resistance, blocking resistance) may be deteriorated. On the other hand, even when the glass transition temperature exceeds 30 ° C., the movement of the molecular chain under low temperature drying is inhibited, so the compatibility of the core component and shell component during film formation becomes insufficient, and the physical properties of the coating film ( Substrate adhesion, water friction resistance) may be deteriorated.

The above glass transition temperature (Tg) refers to the theoretical value calculated from the FOX equation below.
<FOX type> 1 / Tg = W1 / Tg1 + W2 / Tg2 + ... + Wi / Tgi + ... + Wn / Tgn
[In the above FOX formula, the glass transition temperature of the homopolymer of each monomer constituting the polymer composed of n types of monomers is Tgi (K), the mass fraction of each monomer is Wi, and (W1 + W2 + ... + Wi +... Wn = 1). ]

  Water is mentioned as an aqueous medium used at the time of the synthesis | combination of a core-shell type resin fine particle dispersion (B). A hydrophilic organic solvent can also be used as long as the object of the present invention is not impaired.

  The polymerization initiator used in obtaining the core-shell type resin fine particle dispersion (B) used in the present invention is not particularly limited as long as it has the ability to initiate radical polymerization, and known oil-soluble polymerization initiators and A water-soluble polymerization initiator can be used.

The oil-soluble polymerization initiator is not particularly limited, and examples thereof include benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexanoate), and tert-butyl peroxide. Organic peroxides such as oxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide;
2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1 Mention may be made of azobis compounds such as' -azobis-cyclohexane-1-carbonitrile. These can be used alone or in combination of two or more.

In the present invention, a water-soluble polymerization initiator is preferably used. For example, ammonium persulfate (APS), potassium persulfate (KPS), hydrogen peroxide, 2,2′-azobis (2-methylpropionamidine) dihydro Conventionally known materials such as chloride can be preferably used.

Moreover, when performing emulsion polymerization, a reducing agent can be used together with a polymerization initiator if desired. Thereby, it becomes easy to accelerate the emulsion polymerization rate or to perform the emulsion polymerization at a low temperature.

Examples of such a reducing agent include reducing organic compounds such as metal salts such as ascorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate, sodium thiosulfate, sodium sulfite, sodium bisulfite, Examples include reducing inorganic compounds such as sodium bisulfite, ferrous chloride, Rongalite, thiourea dioxide, and the like. These reducing agents are preferably used in an amount of 0.05 to 5.0 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer. In addition, it can superpose | polymerize also by a photochemical reaction, radiation irradiation, etc. irrespective of an above described polymerization initiator. The polymerization temperature is not less than the polymerization start temperature of each polymerization initiator. For example, in the case of a peroxide-based polymerization initiator, it may be usually about 80 ° C. The polymerization time is not particularly limited, but is usually 2 to 24 hours.

Further, if necessary, sodium acetate, sodium citrate, sodium bicarbonate, etc. as a buffering agent, and octyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl mercaptan as a chain transfer agent A suitable amount of mercaptans such as t-dodecyl mercaptan can be used.

Next, the resin fine particle dispersion (D) used in the present invention will be described.
The resin fine particle dispersion (D) is a conventionally known emulsion weight in which an ethylenically unsaturated monomer (d) is emulsion-polymerized in an aqueous medium using a radical polymerization initiator in the presence of a surfactant (C). It can be obtained legally.

As the surfactant (C), conventionally known ones such as a reactive surfactant having an ethylenically unsaturated group and a non-reactive surfactant having no ethylenically unsaturated group can be arbitrarily used. .

Reactive surfactants having an ethylenically unsaturated group can be further broadly classified into anionic and nonionic ones. When a reactive surfactant is used, the elution component from the coating film decreases, so that the coating film resistance is improved. These reactive surfactants may be used alone or in combination of two or more.

As an example of the anionic reactive surfactant having an ethylenically unsaturated group, specific examples thereof are illustrated below, but the emulsifiers that can be used in the present invention are not limited to those described below. . Examples of the surfactant include alkyl ethers (commercially available products include, for example, Aqualon KH-05, KH-10, KH-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA rear soap SR-10N, SR manufactured by ADEKA Corporation. -20N, LATEMUL PD-104 manufactured by Kao Corporation), etc .;
Sulfosuccinic acid ester-based (for example, LATEMUL S-120, S-120A, S-180P, S-180A, Sanyo Chemical Co., Ltd., Elemiol JS-2, etc., manufactured by Kao Corporation);
Alkyl phenyl ether type or alkyl phenyl ester type (commercially available products include, for example, Aqualon H-2855A, H-3855B, H-3855C, H-3856, HS-05, HS-10, HS, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. -20, HS-30, Adeka Soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc. manufactured by ADEKA Corporation);
(Meth) acrylate sulfate-based (commercially available products include, for example, Antox MS-60, MS-2N, Sanyo Chemical Industries Co., Ltd., Elemiol RS-30, manufactured by Nippon Emulsifier Co., Ltd.);
Examples of the phosphoric acid ester (commercially available products include H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap PP-70 manufactured by ADEKA Co., Ltd.), and the like.

Nonionic reactive surfactants that can be used in the present invention include, for example, alkyl ethers (commercially available products such as Adeka Soap ER-10, ER-20, ER-30, and ER- manufactured by ADEKA Corporation). 40, Latemu PD-420, PD-430, PD-450, etc. manufactured by Kao Corporation);
Alkyl phenyl ether type or alkyl phenyl ester type (commercially available products include, for example, Aqualon RN-10, RN-20, RN-30, RN-50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA rear soap NE- manufactured by ADEKA Co., Ltd. 10, NE-20, NE-30, NE-40, etc.);
(Meth) acrylate sulfate esters (commercially available products include, for example, RMA-564, RMA-568, and RMA-1114 manufactured by Nippon Emulsifier Co., Ltd.).

  Non-reactive surfactants can also be broadly classified into anionic and non-reactive nonionic types.

Examples of non-reactive nonionic emulsifiers include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether;
Polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether;
Sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate;
Polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate;
Polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate;
Glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride;
Examples include polyoxyethylene / polyoxypropylene / block copolymer, polyoxyethylene distyrenated phenyl ether, and the like.

Examples of non-reactive anionic surfactants include higher fatty acid salts such as sodium oleate;
Alkylaryl sulfonates such as sodium dodecylbenzenesulfonate;
Alkyl sulfate salts such as sodium lauryl sulfate;
Polyoxyethylene alkyl ether sulfate esters such as sodium polyoxyethylene lauryl ether sulfate;
Polyoxyethylene alkylaryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate;
Alkyl sulfosuccinic acid ester salts such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof;
Examples thereof include polyoxyethylene distyrenated phenyl ether sulfate salts.

The amount of the surfactant used at the time of emulsion polymerization is preferably 0.5 to 3.0 parts by weight with respect to 100 parts by weight as the total of the ethylenically unsaturated monomer (d). If the amount of the emulsifier is less than 0.5 parts by weight, a resin fine particle dispersion having good dispersion stability may not be obtained due to destabilization during emulsion polymerization. On the other hand, when the amount of the surfactant exceeds 3.0 parts by weight, the eluted components increase, and the coating film resistance may deteriorate.

Examples of the ethylenically unsaturated monomer (d) used in obtaining the resin fine particle dispersion (D) used in the present invention include the ethylenically unsaturated monomer (a) and the ethylenically unsaturated monomer. Although the ethylenically unsaturated monomer mentioned by (b) can be used, it is not specifically limited to these. These can be used alone or in combination of two or more.

The polymerization initiator used in obtaining the resin fine particle dispersion (D) used in the present invention is not particularly limited as long as it has the ability to initiate radical polymerization, and is known oil-soluble polymerization initiator or water-soluble. A polymerization initiator can be used. Moreover, a reducing agent and a buffering agent can also be used together if desired.

As the polymerization initiator, the reducing agent, and the buffering agent, the polymerization initiator, the reducing agent, the buffering agent, and the like mentioned in the description of the core-shell type resin fine particle dispersion (B) can be used.

Further, the resin fine particle dispersion (D) obtained after the completion of emulsion polymerization can be neutralized with a basic compound. As a basic compound, the basic compound used by neutralization of said water-soluble resin (A) is mentioned.

The average particle size of the resin fine particle dispersion (D) is preferably in the range of 80 to 200 nm. If the average particle size is less than 80 nm, the dispersion stability of the resin fine particle dispersion in the ink composition is lowered, which may adversely affect the storage stability, re-dissolvability, and plate washability of the ink. On the other hand, if it exceeds 200 nm, the film-forming property at the time of drying is lowered, and the physical properties of the coating film (substrate adhesion, water friction resistance, water blocking resistance) may be deteriorated.

The acid value of the resin fine particle dispersion (D) is preferably in the range of 0 to 30 mgKOH / g. When the acid value exceeds 30 mgKOH / g, poor drying occurs, and the physical properties of the coating film (substrate adhesion, water friction resistance, water blocking resistance) are significantly lowered. Moreover, the odor of the coating film after drying also deteriorates.

The glass transition temperature (Tg) of the resin fine particle dispersion (D) is preferably in the range of −5 to 30 ° C. When the glass temperature is less than −5 ° C., the strength of the coating film is lowered and the physical properties of the coating film (base material adhesion, water friction resistance, blocking resistance) may be deteriorated. On the other hand, even when the glass transition temperature exceeds 30 ° C., the film formation is inhibited, so the compatibility of the core component and the shell component becomes insufficient, and the physical properties of the coating film (base material adhesion, water friction resistance) It may get worse.

  By combining the core-shell type resin fine particle dispersion (B) and the resin fine particle dispersion (D) described above, on a nonpolar film substrate, which tends to cause poor drying due to residual components, compared to a paper substrate that penetrates. However, under low temperature drying conditions, it is possible to exhibit excellent water friction resistance, substrate adhesion, and water blocking resistance, and the odor of the coating film is greatly reduced. Furthermore, in terms of ink physical properties, good dispersion stability, re-dissolvability and detergency are secured.

In the binder composition for water-based inks of the present invention, the content of the resin fine particle dispersion (D) is preferably 25 to 75% by weight in a total of 100% by weight of resin solids. When the amount of the resin fine particle dispersion (D) is less than 25% by weight, the coating film tends to be poorly dried, and the water blocking resistance may be lowered. Moreover, the odor from a coating film may worsen. On the other hand, when it exceeds 75 parts by weight, the printability is deteriorated and the water friction resistance may be deteriorated. Furthermore, the re-dissolvability and detergency of the ink may deteriorate.

Next, the water-based ink composition of the present invention will be described. The water-based ink composition of the present invention contains a pigment dispersion resin (E), a pigment (F), a hydrophilic solvent (G) and water in addition to the water-based ink binder composition.

The binder composition for water-based inks of the present invention is preferably used in an amount of 5 to 40% by weight in terms of resin solid content in 100% by weight of the water-based ink composition, and more preferably in the range of 10 to 30% by weight. When the resin solid content is less than 5%, the leveling property is deteriorated, and at the same time, the binding force between the base material and the pigment or between the pigments becomes insufficient, so that the coating film properties (base material adhesion, water friction resistance) are improved. May decrease. On the other hand, when it exceeds 40% by weight, the viscosity of the ink composition is remarkably increased, the dispersion stability of the ink is deteriorated, the drying failure is caused, and the physical properties of the coating film (base material adhesion, water friction resistance) are deteriorated. There is a case.

As the pigment dispersion resin (E) used for pigment dispersion, any water-soluble resin can be used as long as it maintains ink stability and has pigment dispersion ability.
As the pigment dispersion resin (E), for example,
Polyvinyl alcohol, polyvinyl pyrrolidone (commercially available products such as K-30, K-60, K-90, etc. manufactured by ISP), polyethylene glycol, poly (meth) acrylic acid, (meth) acrylic acid- (meth) acrylic acid Alkyl ester copolymer, styrene- (meth) acrylic acid- (meth) acrylic acid alkyl ester copolymer, styrene- (meth) acrylic acid copolymer, maleic acid- (meth) acrylic acid alkyl ester copolymer, Styrene-maleic acid copolymer, styrene-maleic acid- (meth) acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene- (meth) acrylic acid copolymer, vinyl naphthalene-malein Acid copolymer, vinylpyrrolidone- (meth) acrylic acid alkyl ester copolymer, vinylpyrrolidone- Styrene copolymer, vinylpyrrolidone-vinyl acetate copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate- (meth) acrylic acid copolymer, vinyl acetate-crotonic acid copolymer, polyvinyl sulfonic acid, polyvinyl sulfone Sodium sulfonate, polystyrene sulfonate, sodium polystyrene sulfonate (Polynas PS-1, Polynas PS-5, etc., manufactured by Tosoh Corporation), styrene sulfonic acid-maleic acid copolymer, polyitaconic acid, polyhydroxyethyl (meth) acrylate, poly Water-soluble vinyl copolymers such as (meth) acrylamide, (meth) acrylamide- (meth) acrylic acid copolymer, polyvinyl methyl ether, methyl vinyl ester, carboxy vinyl polymer;
A water-soluble polyurethane resin which is a urethane resin obtained by polyaddition reaction of polyisocyanate and polyol, and the entire resin is water-solubilized by introduction of hydrophilic groups;
A water-soluble polyester resin which is a polyester resin obtained by polycondensation reaction of a polyvalent carboxylic acid and a polyol, and the entire resin is water-solubilized by introduction of a hydrophilic group;
Cellulose derivatives such as methyl cellulose, ethyl cellulose, propyl cellulose, ethyl methyl cellulose, hydroxyalkyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, alkali metal carboxymethyl cellulose, alkali metal cellulose sulfate, cellulose graft polymer;
Polypeptides such as polyglutamic acid and polyaspartic acid;
However, it is not particularly limited to these. These can be used alone or in combination of two or more.

Among the water-soluble resins mentioned above, from the viewpoint of excellent pigment adsorption ability and dispersion stability, the pigment dispersion resin (E) is a meth) acrylic acid- (meth) acrylic acid alkyl ester copolymer, styrene- ( (Meth) acrylic acid- (meth) acrylic acid alkyl ester copolymer, styrene- (meth) acrylic acid copolymer, maleic acid- (meth) acrylic acid alkyl ester copolymer, styrene-maleic acid copolymer, styrene A maleic acid- (meth) acrylic acid alkyl ester copolymer and a styrene-maleic acid half ester copolymer are preferred. Further, these resins may be synthesized by solution polymerization or bulk polymerization using a radical initiator, or commercially available products may be used. Moreover, the basic compound described above can be used as needed.

As commercially available products, for example, BASF Corp. JONCRYL67, JONCRYL678, JONCRYL586, JONCRYL611, JONCRYL683, JONCRYL690, JONCRYL57J, JONCRYL60J, JONCRYL61J, JONCRYL62J, JONCRYL63J, JONCRYLHPD-96J, JONCRYL501J, JONCRYLPDX-6102B, manufactured by BYK Chemie DISPERBYK, DISPERBYK180, DISPERBYK187 , DISPERBYK190, DISPERBYK191, DISPERBYK194, DISPERBYK2010, DISPERBYK2015, DISPERBYK2090, DISPERBYK2091, DISPERBYK2095, DISPERBYK2155, Zeneca SOLSPERS41000, Sartomer, SMA1000H, SMA1440H, SMA2000H, SMA3000H, etc.

Further, from the viewpoint of compatibility with the aqueous binder resin composition, the pigment dispersion resin (E) is composed of an aromatic ethylenically unsaturated monomer (e-1), a carboxyl group-containing ethylenically unsaturated monomer (e- A water-soluble resin obtained by polymerizing an ethylenically unsaturated monomer (e) containing 2) is preferred.

Examples of the ethylenically unsaturated monomer (e) include the ethylenically unsaturated monomer (a) described above.

It is preferable to contain 20 to 70% by weight of the aromatic ethylenically unsaturated monomer (e-1) in a total of 100% by weight of the ethylenically unsaturated monomer (e). When the content of the aromatic ethylenically unsaturated monomer (e-1) is less than 20% by weight, compatibility with the resin fine particle dispersion is reduced during film formation, and the coating film properties (substrate adhesion, (Water resistance) may be reduced. On the other hand, even when it exceeds 70% by weight, the compatibility with the resin fine particle dispersion may be lowered, and the physical properties of the coating film (base material adhesion, water friction resistance) may be lowered.

It is preferable to contain 10 to 40% by weight of the carboxyl group-containing ethylenically unsaturated monomer (e-2) in a total of 100% by weight of the ethylenically unsaturated monomer (e). When the carboxyl group-containing ethylenically unsaturated monomer (e-2) is less than 10% by weight, compatibility with the resin fine particle dispersion may be reduced during film formation, and film properties may be deteriorated. On the other hand, if it exceeds 40% by weight, drying failure may occur and the physical properties of the coating film (substrate adhesion, water friction resistance, blocking resistance) may be deteriorated. The pigment dispersion resin (E) having the above composition is very excellent in compatibility with the resin fine particle dispersion, and forms a uniform coating film even under low temperature drying. Therefore, it can be expected to further improve the physical properties of the coating film by combining them.

The pigment-dispersed resin (E) having the above composition is very excellent in compatibility with the binder resin composition for water-based inks of the present invention, and forms a uniform coating film with excellent coating film resistance even under low temperature drying. . Therefore, it can be expected to further improve the physical properties of the coating film by combining them.

The pigment dispersion resin (E) is preferably used in the range of 10 to 60 parts by weight in terms of solid content with respect to 100 parts by weight of the pigment. When the pigment dispersion resin is less than 10 parts by weight with respect to 100 parts by weight of the pigment, the pigment dispersion stability may be lowered, and the dispersion stability and storage stability of the ink composition may be deteriorated. On the other hand, when the pigment dispersion resin exceeds 60 parts by weight with respect to 100 parts by weight of the pigment, the viscosity of the ink composition is remarkably increased, which may adversely affect the storage stability of the ink. Moreover, since generation | occurrence | production of the poor drying of a coating film and the elution component to water increase, about a coating-film physical property (base-material adhesiveness, water-friction resistance, blocking resistance), it may fall.

As the pigment (F), for example, achromatic pigments such as carbon black, titanium oxide, calcium carbonate, or chromatic organic pigments can be used. Examples of organic pigments include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa Yellow, Benzidine Yellow, and pyrazolone red, soluble azo pigments such as Ritol Red, Helio Bordeaux, Pigment Scarlet, and Permanent Red 2B, alizarin, indanthrone, and thioindigo. Derivatives from vat dyes such as maroon, phthalocyanine organic pigments such as phthalocyanine blue and phthalocyanine green, quinacridone organic pigments such as quinacridone red and quinacridone magenta, perylene organic pigments such as perylene red and perylene scarlet, isoindolinone yellow , Isoindolinone organic pigments such as isoindolinone orange, pyranthrone organic pigments such as pyranthrone red and pyranthrone orange, thioy Digo-based organic pigments, condensed azo-based organic pigments, benzimidazolone-based organic pigments, quinophthalone-based organic pigments such as quinophthalone yellow, isoindoline-based organic pigments such as isoindoline yellow, and other pigments such as flavanthrone yellow and acylamide yellow Nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like.

  When organic pigments are exemplified by color index (CI) numbers, C.I. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 8893, 109, 110, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153 154, 155, 166, 168, 180, 185, C.I. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, C.I. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, C.I. I. Pigment violet 19, 23, 29, 30, 37, 40, 50, C.I. I. Pigment blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, C.I. I. Pigment green 7, 36, C.I. I. Pigment brown 23, 25, 26, and the like.

  Specific examples of carbon black include “Special Black 350, 250, 100, 550, 5, 4, 4A, 6” “Printex U, V, 140 U, 140 V, 95, 90, 85, 80, 75, 55, manufactured by Degussa. 45, 40, P, 60, L6, L, 300, 30, 3, 35, 25, A, G ", Cabot's" REGAL 400R, 660R, 330R, 250R "," MOGUL E, L ", Mitsubishi Chemical “MA7, 8, 11, 77, 100, 100R, 100S, 220, 230” “# 2700, # 2650, # 2600, # 200, # 2350, # 2300, # 2200, # 1000, # 990, # 980, # 970, # 960, # 950, # 900, # 850, # 750, # 650, # 52, # 50, # 47, # 45, # 4 5L, # 44, # 40, # 33, # 332, # 30, # 25, # 20, # 10, # 5, CF9, # 95, # 260 ”and the like.

Specific examples of titanium oxide include “Taipeku CR-50, 50-2, 57, 80, 90, 93, 95, 953, 97, 60, 60-2, 63, 67, 58, 58- manufactured by Ishihara Sangyo Co., Ltd. 2, 85 "" Tipekes R-820, 830, 930, 550, 630, 680, 670, 580, 780, 780-2, 850, 855 "," Tipekes A-100, 220 "," Tipekes W-10 "," Tipekes " PF-740, 744 "" TTO-55 (A), 55 (B), 55 (C), 55 (D), 55 (S), 55 (N), 51 (A), 51 (C) " "TTO-S-1, 2", "TTO-M-1, 2", "Titanics JR-301, 403, 405, 600A, 605, 600E, 603, 805, 806, 701, 800, 808" manufactured by Teika "Titanic EN-1, C, 3, 4, 5 ", and the like manufactured by Du Pont" Taipyua R-900,902,960,706,931 ". The organic pigments such as yellow, magenta, cyan and black are preferably blended at a ratio of 5 to 30% by weight in 100% by weight of the water-based ink composition. Moreover, in the case of white titanium oxide, it is preferable to mix | blend normally in the ratio of 10 to 60 weight%.

Furthermore, the water-based ink composition of the present invention contains a hydrophilic solvent (G) for the purpose of controlling the wettability to the substrate and the drying property of the ink.

In 100% by weight of the water-based ink composition, the hydrophilic solvent (G) is preferably contained in an amount of 1 to 10% by weight, more preferably in the range of 2 to 5% by weight. If the hydrophilic solvent (G) is less than 1% by weight, the leveling property may be deteriorated and the physical properties of the coating film (substrate adhesion, water friction resistance) may be lowered. On the other hand, when the content of the hydrophilic solvent (G) exceeds 10% by weight, the coating film is poorly dried, and the physical properties of the coating film (substrate adhesion, water friction resistance, blocking resistance) are lowered. There is a case.

Examples of the hydrophilic solvent (G) include monohydric alcohols such as ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, and 2-methyl-2-propanol. solvent;
Ethylene glycol, 1,3-propanediol, propylene glycol, 1,2-butanediol, 1,4-butanediol, pentylene glycol, 1,2-hexanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol Glycol solvents such as tetraethylene glycol;
Ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, triethylene glycol monoisopropyl Ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether , Diethylene glycol monohexyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, glycol ethers such as tripropylene glycol monomethyl ether solvent;
Lactam solvents such as N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, ε-caprolactam;
Examples include amide solvents such as formamide, N-methylformamide, N, N-dimethylformamide, Idemitsu ecamide M-100, and equamide B-100. These can be used alone or in combination of two or more.

In the water-based ink composition of the present invention, a water-soluble hydrazide compound can be appropriately used for the purpose of improving adhesion to a substrate and forming a keto-hydrazide bridge. Examples of the water-soluble hydrazide compound include adipic acid dihydrazide and water-soluble resins in which a polyfunctional hydrazide group is modified.
When the resin fine particle dispersion contains a keto group, it is preferably added so that the hydrazide group is equimolar to the keto group.

For the purpose of further improving the adhesion to the substrate, the water-based ink composition of the present invention has a reactive group such as a carbodiimide group within a range that does not adversely affect the storage stability of the ink and the compatibility between resins. A cross-linking agent containing can also be used in combination. Examples of commercially available crosslinking agents include Nisshinbo Co., Ltd., Carbodilite E-02, E-03A, SV-02, V-02, V-02-L2, and V-04.

The amount of the crosslinking agent used in combination is preferably about 0.5 to 15% by weight in terms of solid content in 100% by weight of the aqueous ink composition.

In the aqueous ink composition of the present invention, a commercially available wax fine particle dispersion can be used for the purpose of improving the friction resistance of the coating film. Examples of the wax resin fine particle dispersion include Chemipearl W100, W200, W300, W310, W306, W400, W401, W4005, W410, W500, WF640, W700, W800, W900, W950, WH201, and WP100 manufactured by Mitsui Chemicals. Is mentioned.

The amount of the wax fine particle dispersion added is about 1 to 5% by weight in terms of solid content in 100% by weight of the water-based ink composition in consideration of the balance between the improvement of the friction resistance in the physical properties of the coating film and the adverse effect on the hue. Is preferred.

Also. The water-based ink composition of the present invention can use various surface conditioners for the purpose of adjusting the leveling property to the substrate. As the surface conditioner, for example, Surfinol 104E, 104H, 104A, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, PSA-336, 61, 2502, manufactured by Nissin Chemical Co., Ltd. , DYNOL 604, 607, BYK-381, 3441, 302, 307, 325, 331, 333, 342, 345, 346, 347, 348, 349, 378, 3455, etc., manufactured by BYK Chemie.

The addition amount of the surface modifier is preferably about 0 to 1% by weight in terms of solid content in 100% by weight of the water-based ink composition in consideration of the balance of adverse effects on the physical properties of the coating film.

The minimum film-forming temperature (MFT) of the water-based ink composition of the present invention is preferably 0 ° C. or lower. When the temperature exceeds 0 ° C., the film-forming property at the time of drying becomes insufficient, and the water friction resistance, substrate adhesion, and water blocking resistance may decrease.

The water-based ink composition of the present invention has good substrate adhesion to nonpolar film substrates such as polypropylene, polyethylene and polyethylene terephthalate even under low temperature drying conditions, and has excellent water rub resistance and blocking resistance. Therefore, it is possible to expand to water-based flexographic printing and gravure printing, which has been difficult to expand on substrates such as nonpolar film substrates. Moreover, it can also be used for the purpose of improving the physical properties of the coating film with respect to conventional substrates such as permeable substrates such as fine paper, art paper, and coated paper.

Although it is a drying process of a water-based ink composition, any temperature can be applied as long as it does not adversely affect the substrate. In aqueous flexographic printing, it is common to process at a low temperature of 40 to 100 ° C. for 1 to 200 seconds.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples, “part” represents “part by weight” and “%” represents “% by weight”.

<Production of water-soluble resin (A)>
[Production Example 1]
In a separate reaction vessel equipped with a stirrer, thermometer, two dropping funnels, and reflux, 94.0 parts of methyl isobutyl ketone was charged and heated to 100 ° C. under nitrogen reflux with stirring. Next, in two dropping funnels, 55.0 parts of styrene, 30.0 parts of acrylic acid, and 15.0 parts of lauryl methacrylate were dropped from one side over 3 hours. From the other side, 10.0 parts of dimethyl 2,2′-azobisisobutyrate was dissolved in 12.0 parts of methyl isobutyl ketone and added dropwise over 4 hours. After completion of dropping, the reaction was further continued for 10 hours. After cooling, the resulting water-soluble resin (A) solution was neutralized by adding 28.3 parts of 25% aqueous ammonia. Furthermore, ion exchange water was added, solvent substitution was performed while heating, and the aqueous solution of water-soluble resin (A) was obtained. Finally, the solid content of the water-soluble resin (A) solution was adjusted to 35.0% with ion-exchanged water. The acid value of the water-soluble resin (A) was 212, and the weight average molecular weight was 12,800.

[Production Examples 2 to 7]
A water-soluble resin (A) solution was prepared in the same manner as in Production Example 1 with the composition shown in Table 1. 25% ammonia water as a neutralizing agent was added so that the carboxyl group of the water-soluble resin (A) and ammonia were equimolar. Further, the same operation as in Production Example 1 was performed to prepare a water-soluble resin (A) aqueous solution having a solid content of 35%. About water-soluble resin (A), the acid value and the weight average molecular weight were evaluated.

[Acid value]
Number of milligrams of potassium hydroxide required to neutralize acidic components contained in 1 g of resin. The water-soluble resin (A) thus dried was subjected to potentiometric titration with a potassium hydroxide / ethanol solution according to the method described in JIS K2501.

[Weight average molecular weight]
The weight average molecular weight is a value in terms of polystyrene as measured by GPC (gel permeation chromatography). The dried water-soluble resin (A) is dissolved in tetrahydrofuran to prepare a 0.1% solution, which is prepared by Tosoh HLC-8320-GPC (column number M-0053, molecular weight measurement range of about 2,000 to about 4,000,000). The weight average molecular weight was measured.

<Manufacture of core-shell type resin fine particle dispersion (B)>
[Production Example 8]
In another reaction vessel equipped with a stirrer, a thermometer, two dropping funnels, and a reflux condenser, 91.8 parts of ion-exchanged water and 40.5 parts of the water-soluble resin (A) solution prepared in Production Example 1 were charged and stirred. The temperature was raised to 80 ° C. under nitrogen reflux. Next, in two dropping funnels, 20.0 parts of styrene, 18.0 parts of benzyl methacrylate, and 62.0 parts of n-butyl acrylate were dropped from one side over 2 hours. From the other side, 4.0 parts of ammonium persulfate 20% aqueous solution (0.8 parts in solid content) was added dropwise over 2 hours. After completion of the dropwise addition, the mixture was further reacted for 4 hours to obtain a resin fine particle dispersion. The solid content of the resin fine particle dispersion was adjusted to 45.0% with ion-exchanged water. The acid value of the resin fine particle dispersion was 61, the glass transition temperature (Tg) was 7 ° C., and the average particle size was 84 nm. The acid value of the resin fine particle dispersion was calculated from the acid value of the water-soluble resin (A) and the charged amount. The glass transition temperature (Tg) was calculated from the composition of the ethylenically unsaturated monomer by the FOX equation described above.

[Production Examples 9 to 21]
A resin fine particle dispersion was prepared in the same manner as in Production Example 1 with the formulation shown in Table 2. For Production Examples 15 and 21, after synthesis, adipic acid dihydrazide as a crosslinking agent was added so that the hydrazide group was equimolar with respect to the keto group in the resin fine particle dispersion. As in Production Example 8, the solid content of the resin fine particle dispersion was adjusted to 45% with ion-exchanged water. About the obtained resin fine particle dispersion, it evaluated about the average particle diameter.

[Average particle size]
The resin fine particle dispersion was diluted with water 500 times, and about 5 ml of the diluted solution was measured by a dynamic light scattering measurement method (measurement device manufactured by Nikkiso Co., Ltd.). The peak of the volume particle size distribution data (histogram) obtained at this time was defined as the average particle size.

<Production of resin fine particle dispersion (D)>
[Production Example 22]
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, 39.0 parts of ion-exchanged water and Hightenol LA-12 as a surfactant (C) (active ingredient: 95%, manufactured by Daiichi Kogyo Seiyaku) 0.5 parts, and 25.0 parts of styrene, 30.0 parts of methyl methacrylate, 41.0 parts of 2-ethylhexyl acrylate, 1.0 part of 2-hydroxyethyl acrylate, 3-methacryloxypropyltriethoxysilane An emulsion prepared by stirring and mixing 0.5 parts, 1.0 part of acrylamide, 1.5 parts of acrylic acid, 66.0 parts of ion-exchanged water, and 1.0 part of Hytenol LA-12 as an emulsifier, 7.0 parts were added. After the internal temperature was raised to 80 ° C. and sufficiently substituted with nitrogen, 12.0 parts of a 5% aqueous solution of potassium persulfate was added to initiate polymerization. While maintaining the internal temperature at 80 ° C., the remainder of the emulsion was added dropwise over 3 hours, and stirring was further continued for 2 hours. After completion of the reaction, the temperature was cooled to 30 ° C. and neutralized with 1.4 parts of 25% aqueous ammonia. Furthermore, the solid content of the resin fine particle dispersion (D) was adjusted to 45.0% with ion-exchanged water. The acid value of the resin fine particle dispersion was 10, the glass transition temperature (Tg) was 17 ° C., and the average particle size was 125 nm. The acid value of the resin fine particle dispersion was calculated from the charged amount of the carboxyl group-containing ethylenically unsaturated monomer. The glass transition temperature (Tg) was calculated from the composition of the ethylenically unsaturated monomer by the FOX equation described above.

[Production Examples 23 to 31]
A resin fine particle dispersion (D) was prepared in the same manner as in Production Example 22 with the formulation shown in Table 3. After the synthesis, the mixture was neutralized with 25% aqueous ammonia so that ammonia was equimolar with respect to the carboxyl group. In the same manner as in Production Example 22, the solid content of the resin fine particle dispersion was all adjusted to 45.0% with ion-exchanged water. About the obtained resin fine particle dispersion, the average particle diameter was evaluated.

<Preparation of binder resin composition for water-based ink>
[Example 1]
A binder resin composition for aqueous ink was prepared by stirring 50.0 parts of the resin fine particle dispersion (B) synthesized in Production Example 8 and 50.0 parts of the resin fine particle dispersion (D) synthesized in Production Example 22 with a homomixer. Prepared. (Resin solid content 45.0%)

[Examples 2 to 15 and Comparative Examples 1 to 5]
Binder compositions for water-based inks were prepared in the same manner as in Example 1 with the blending compositions shown in Tables 4 and 5.

<Manufacture of pigment dispersion resin (E)>
[Production Example 32]
In a separate reaction vessel equipped with a stirrer, thermometer, two dropping funnels, and reflux, 94.0 parts of methyl isobutyl ketone was charged and heated to 100 ° C. under nitrogen reflux with stirring. Next, in two dropping funnels, 55.0 parts of styrene, 5.0 parts of α-methylstyrene, 30.0 parts of methacrylic acid, and 15.0 parts of ethyl acrylate were dropped from one side over 3 hours. From the other side, 5 parts of dimethyl 2,2′-azobisisobutyrate was dissolved in 10 parts of methyl isobutyl ketone and added dropwise over 4 hours. After completion of the dropwise addition, the reaction was completed by further reacting for 10 hours. The obtained pigment dispersion resin (E) solution was neutralized by adding 23.7 parts of 25% aqueous ammonia. Furthermore, ion exchange water was added, solvent substitution was performed while heating, and the aqueous solution of water-soluble resin (A) was obtained. Finally, ion exchange water was further added to adjust the solid content of the water-soluble resin (A) solution to 30.0%. The acid value of the pigment dispersion resin (E) was 179, and the weight average molecular weight was 10,500.

[Production Examples 33 to 38]
With the composition shown in Table 6, pigment dispersion resin (E) aqueous solutions of Production Examples 33 to 38 were prepared in the same manner as in Production Example 32. 25% aqueous ammonia as a neutralizing agent was added to neutralize the carboxyl group of the pigment-dispersed resin (E) so that ammonia was equimolar, and the same operation as in Production Example 32 was performed. An aqueous pigment dispersion resin (E) solution having a content of 30.0% was prepared. Further, as in Production Examples 39 and 40, when using a commercially available solid resin as a pigment dispersant, ion exchange water is added, and 25% ammonia water is used so that the carboxyl group and ammonia of the pigment dispersion resin (E) are equal. It was added so as to have a molar amount, and water-solubilized while heating and stirring to adjust the solid content to 30.0%. Table 7 shows an outline of the commercially available solid resin used. About the pigment dispersion resin (E), the acid value and the weight average molecular weight were evaluated by the same method as the water-soluble resin (A).

<Production of concentrated pigment dispersion>

[Production Example 41]
<Production of concentrated white pigment dispersion>
67.5 parts of pigment [Taipeke CR80 manufactured by Ishihara Sangyo Co., Ltd.], 21.3 parts of pigment dispersant aqueous solution (solid content: 30.0%) of Production Example 32, 5.8 parts of ion-exchanged water, surface conditioner [Surfinol 420 Nissin Chemical Industry Co., Ltd.] 0.4 parts was dispersed with a paint conditioner for 2 hours to obtain a concentrated white pigment dispersion.

[Production Examples 42 to 49]
A concentrated white pigment dispersion was prepared in the same manner as in Production Example 41 with the formulation shown in Table 8.

[Production Example 50]
<Manufacture of concentrated indigo pigment dispersion>
35.9 parts of pigment [Lionol Blue FG7330, manufactured by Toyocolor Co., Ltd.], 21.5 parts of pigment dispersant aqueous solution (solid content 30.0%) of Production Example 32, 39.7 parts of ion-exchanged water, surface conditioner [ Surfinol 420, manufactured by Nissin Chemical Industry Co., Ltd., 0.4 parts was dispersed with a paint conditioner for 2 hours to obtain a concentrated indigo pigment dispersion.

[Production Examples 51-58]
Concentrated indigo pigment dispersions were prepared in the same manner as in Production Example 50 with the composition shown in Table 9.

<Preparation of water-based ink composition>
[Example 16]
47.5 parts of concentrated white pigment dispersion of Production Example 24, 5 parts of Chemipearl W500, N-propanol part 2 as a hydrophilic solvent with respect to 40.2 parts of binder resin composition for water-based ink obtained in Example 1 0.5 part, 1.0 part of diethylene glycol monoethyl ether and 3.8 parts of ion-exchanged water were added and then kneaded to obtain a white aqueous ink composition.

[Examples 17 to 30 and Comparative Examples 6 to 10]
The composition shown in Table 10 and Table 11 was prepared in the same manner as in Example 16 to obtain a white aqueous ink composition.

[Example 31]
Based on 40.9 parts of the binder resin composition for water-based ink obtained in Example 1, 41.6 parts of the concentrated indigo pigment dispersion of Production Example 50, 4.5 parts of Chemipearl W500, N-propanol as a hydrophilic solvent After adding 3.0 parts and 10.0 parts of ion-exchanged water, the mixture was kneaded to obtain an indigo water-based ink composition.

[Examples 32-45 and Comparative Examples 11-15]
With the composition shown in Table 12 and Table 13, it was prepared in the same manner as in Example 31 to obtain a deep blue water-based ink composition.

[Minimum film forming temperature]
The minimum film-forming temperature (MFT) was measured by applying a water-based ink composition to a glass plate with a 300 µ applicator and applying a thermal gradient tester (manufactured by Rigaku Corporation).

<Evaluation of water-based ink composition>
About the water-based ink composition prepared above, storage stability, re-dissolvability, and plate washability were evaluated as ink physical properties. The aqueous ink composition was applied to a treated OPP (biaxially oriented polypropylene film) substrate using Flexiproof 100 (anilox roller 80 lines / cm). After coating, the substrate was heat-treated in an oven at 60 ° C. for about 1 minute to obtain a coating film for evaluation. Using this, the physical properties of the coating film (substrate adhesion, water friction resistance, water blocking resistance, odor) were evaluated. Tables 14 to 17 show the results.

[Storage stability]
The aqueous ink composition was evaluated for changes in viscosity over time under conditions of 40 ° C. and 1 week. The viscosity was measured using a Zahn cup (No. 4).
The evaluation criteria are as follows. (Practical level is more than ○)
A: Change in the viscosity of the ink is less than ± 10% B: Change in the viscosity of the ink is ± 10% or more and less than ± 15% Δ: Change in the viscosity of the ink is ± 15% or more and less than ± 20% × ; The viscosity change of the ink is ± 20% or more.

[Resolubility]
The aqueous ink composition was coated on the treated OPP with a bar coater (No. 8) and allowed to stand at room temperature for 15 minutes.
After standing, the ink was dripped onto the coated surface, and the time until the ink was redissolved was measured while wiping with time. The evaluation criteria are as follows. (Practical level is more than ○)
◎: Re-dissolve within 30 seconds ○; Re-dissolve within 60 seconds Δ; Re-dissolve within 120 seconds ×: Not re-dissolve after 120 seconds

[Plate washability]
With respect to the flexiproof 100 plate, the plate washability was evaluated using various solvents after ink coating.
The evaluation criteria are as follows. (Practical level is more than △)
○: Washable with alcohol solvent or magic phosphorus (manufactured by Kao Corporation).
Δ: Washable with magic phosphorus (manufactured by Kao Corporation).
X: Cannot be washed with an alcohol solvent or magic phosphorus (manufactured by Kao Corporation).

[Base material adhesion]
Cellophane tape (18 mm width manufactured by Nichiban Co., Ltd.) was applied to the coating film for evaluation, a peel test was performed in the vertical direction, and the substrate adhesion was evaluated from the ratio of the area where the ink was peeled off.
The evaluation criteria are as follows. (Practical level is more than ○)
◎: No ink peeling ○: Some ink peeling (less than 10%)
Δ: Ink peeling (10% or more, less than 50%)
×: Ink peeling is considerable (over 50%)

[Water friction resistance]
The evaluation coating film was immersed in water for 1 minute. After dipping, using Kanakin (JIS L 0803) as a friction element, the surface of the coated film with water was reciprocated 500 times with a load of 500 g using a Gakushin tester (manufactured by Tester Sangyo Co., Ltd.). The water friction resistance was evaluated from the ratio of the area where the ink was peeled off. The evaluation criteria are as follows. (Practical level is more than ○)
◎: No ink peeling ○: Ink peeling slightly (less than 5%)
Δ: Ink peeling (5% or more, less than 30%)
×: Ink peeling is considerable (30% or more)

[Water blocking resistance]
For the coating film for evaluation, a drop of water is dropped, the coated surface and the back surface are overlapped, a load of 5 kg / cm ² is applied by a blocking tester, and left in a constant temperature and humidity room at a temperature of 40 ° C. and a humidity of 80% for 24 hours. did. after that,
The coating film for evaluation was taken out and checked for the presence of ink show-through and the presence of peeling sound. The evaluation criteria are as follows. (Practical level is ○)
◎: Ink does not show through on the back and no peeling sound ○: Ink does not show through on the back, but peels off △: Ink shows through on the back (less than 1% of the total area)
×: The ink is show-through on the back (1% or more of the total area)

[Odor]
A 10 cm × 10 cm evaluation coating film was placed in a 500 ml Mayo bottle and allowed to stand at 40 ° C. for 2 hours. Five people were selected arbitrarily, sniffing the inside of the mayo bottle, and a sensory test was conducted on the blank (uncoated substrate) to feel odor.
The evaluation criteria are as follows. (Practical level is ○)
◎ 5 people do not feel odor ○ Of 5 people, 1 feel odor △ Out of 5 people, 2 feel odor × 3 out of 5 people feel odor

As shown in Table 14 and Table 16, white aqueous ink compositions (Examples 16 to 30) and indigo water-based ink compositions (Examples 31 to 31) using the binder resin compositions for aqueous inks of Examples 1 to 15 were used. 45) has good ink physical properties (storage stability, re-dissolvability, plate washability) and has excellent substrate adhesion, water friction resistance, water friction resistance at low temperature drying against nonpolar film substrates. Expression was confirmed. In addition, the problems of water resistance blocking and odor in the nonpolar film base material that is prone to poor drying are also overcome. All of these items satisfy practically possible levels. On the other hand, as shown in Table 15 and Table 17, white aqueous ink compositions (Comparative Examples 6 to 10) and indigo water-based ink compositions (Comparative Example 11) using the aqueous ink binder compositions of Comparative Examples 1 to 5 were used. In -15), the ink film properties were poor in all cases.

Claims (7)

Acid value of 50 to 90 mgKOH / acid value obtained by polymerizing ethylenically unsaturated monomer (b) in an aqueous medium in the presence of water-soluble resin (A) obtained by polymerizing ethylenically unsaturated monomer (a) g core-shell resin fine particle dispersion (B);
And a resin fine particle dispersion (D) having an acid value of 0 to 30 mg KOH / g obtained by polymerizing an ethylenically unsaturated monomer (d) in an aqueous medium in the presence of a surfactant (C). A binder resin composition for water-based inks. 2. The aqueous composition according to claim 1, wherein the amount of the resin fine particle dispersion (D) is 25 to 75 wt% in terms of solid content in a total of 100 wt% of the resin solid content of the binder resin composition for water-based ink. Binder resin composition for ink. The binder resin composition for water-based inks according to claim 1 or 2, wherein the core-shell resin fine particle dispersion (B) has an average particle size of 45 to 90 nm and a glass transition temperature of -10 to 30 ° C. The binder resin composition for water-based ink according to any one of claims 1 to 3, wherein the resin fine particle dispersion (D) has an average particle size of 80 to 200 nm and a glass transition temperature of -5 to 30 ° C. A water-based ink composition comprising the pigment-dispersed resin (E), the pigment (F) water, the hydrophilic solvent (G), and the binder resin composition for water-based inks according to claim 1. 6. The water-based ink composition according to claim 5, wherein the minimum film-forming temperature of the water-based ink composition is 0 ° C. or less. The water-based ink composition according to claim 5 or 6, which is used for flexographic printing or gravure printing.