JP6330603B2 - Water-based ink resin composition and water-based ink composition - Google Patents

Description

The present invention relates to a resin composition for water-based ink and a water-based ink composition containing the same. More specifically, for water-based inks that exhibit excellent substrate adhesion, water rub resistance, and water blocking resistance to film substrates even under low temperature drying conditions, while having excellent ink dispersion stability and pot life The present invention relates to a resin composition and a water-based ink composition.

In general, a water-based ink composition is composed of a pigment, a pigment dispersion resin, water, a hydrophilic solvent, and a binder resin. Among these, the binder resin is added for the purpose of improving the coating film resistance of the printed matter. Core shell type resin fine particle dispersions obtained by emulsion polymerization of ethylenically unsaturated monomers and water-soluble resins as polymer emulsifiers are often used as binder resins because they can achieve both excellent printability, dispersion stability, and coating film properties. Has been. Such water-based ink compositions have been mainly studied mainly for paper bases, but in recent years, film base materials such as polyolefin and polyethylene terephthalate are used from the viewpoint of energy saving, low cost, and environmental load reduction. Even on the other hand, it is required to exhibit good coating film resistance.

In Patent Document 1 and Patent Document 2, a binder of a core-shell type resin fine particle dispersion in which water-soluble resin (shell component), composition of core component, molecular weight, ratio of core component to shell component, particle diameter, glass transition temperature and the like are defined. A resin composition is disclosed. However, with this resin fine particle dispersion, it is difficult to develop sufficient coating film resistance under low temperature drying in a film substrate that is inferior in drying property to a paper substrate. Patent Literature 3 and Patent Literature 4 disclose a core-shell type resin particle dispersion in which a keto group is introduced into a water-soluble resin (shell component) or a core component. Certainly, the keto-hydrazide crosslinking system is stable even in a one-pack state, and it can be expected to improve the coating film resistance. However, since it is necessary to sufficiently volatilize the water in order to exhibit the effect of this crosslinking system, the water remains under low temperature drying assuming high-speed printing, and it is difficult to dramatically improve the coating film resistance. Further, the remaining hydrazide cross-linking agent may elute and the water resistance may deteriorate. In order to develop sufficient coating film resistance, various types of two-component water-based inks using a highly reactive aqueous cross-linking agent have been studied. However, problems such as significant deterioration in dispersion stability and extremely short pot life occur, and it is often difficult to achieve both physical properties at a practical level.

JP 1996-176486 A JP 2012-116924 A Japanese Patent Laid-Open No. 1995-026196 Japanese Patent Laid-Open No. 1996-113749

Under low-temperature drying conditions, it exhibits excellent substrate adhesion, water rub resistance, and water blocking resistance with respect to the film substrate, while at the same time exhibiting excellent ink dispersion stability and pot life. The present invention relates to provision of a water-based ink composition.

That is, the present invention provides a core-shell resin fine particle dispersion (C) obtained by emulsion polymerization of an ethylenically unsaturated monomer (B) in an aqueous medium using a water-soluble resin (A) having a carboxyl group as a polymer emulsifier. )When,
A carbodiimide group-containing resin fine particle dispersion (D);
The present invention relates to a water-based ink resin composition comprising a water-insoluble epoxy group-containing compound (E).

Furthermore, this invention relates to the said resin composition for water-based inks in which the water-insoluble epoxy group containing compound (E) has an alicyclic epoxy group.

Furthermore, this invention relates to the said resin composition for water-based inks whose glass transition temperature of the core part of a core-shell type resin fine particle dispersion (C) is -30-30 degreeC.

Furthermore, this invention relates to the said resin composition for water-based inks whose weight average molecular weights of a core-shell type resin fine particle dispersion (C) are 200000-500000.

Furthermore, this invention relates to the said resin composition for water-based inks whose quantity of water-soluble resin (A) is 40-150 weight part with respect to a total of 100 weight part of ethylenically unsaturated monomer (B).

Furthermore, the present invention relates to a water-based ink composition comprising the pigment, the pigment dispersion resin (F), water, a hydrophilic solvent, and the above water-based ink resin composition.

Furthermore, in the present invention, the carbodiimide group derived from the dispersion (D) is in the range of 0.1 to 0.5 mol with respect to 1 mol of the carboxyl group derived from the dispersion (C) and the resin (F).
It is related with the said water-based ink composition whose epoxy group derived from a compound (E) is the range of 0.3-2 mol with respect to 1 mol of carbodiimide groups derived from a dispersion resin (D).

Furthermore, this invention relates to the said water-based ink composition used for flexographic printing or gravure printing.

According to the present invention, water-based ink resins exhibit excellent substrate adhesion, water rub resistance, and water blocking resistance to film substrates under low-temperature drying conditions, while also being excellent in ink dispersion stability and pot life. Compositions and aqueous ink compositions could be provided.

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

The core-shell type resin fine particle dispersion (C) for aqueous ink of the present invention starts radical polymerization of an ethylenically unsaturated monomer (B) in an aqueous medium in the presence of a water-soluble resin (A) having a carboxyl group. It can be obtained by emulsion polymerization with an agent. The manufacturing method of a core-shell type resin fine particle dispersion is demonstrated concretely. First, an aqueous medium, a basic compound, and a water-soluble resin (A) are charged into a reaction vessel, and dissolved by heating. Thereafter, the 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. After completion of dropping of the ethylenically unsaturated monomer, the core-shell resin fine particle dispersion can be obtained by further reacting for several hours. 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 in an aqueous medium. The water-soluble resin (A) acts as a protective colloid (shell component) in the aqueous medium and stabilizes the precipitated 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 in synthesizing the resin fine particle dispersion can be obtained by solution polymerization or bulk polymerization with a radical initiator and neutralizing a carboxyl group in the resin with a basic compound.

The water-soluble resin (A) is arbitrary as long as it has a carboxyl group and is neutralized with a basic compound and dissolved or dispersed in an aqueous medium and functions as a protective colloid of the core component. Can be used. Examples of the resin skeleton include acrylic resin, styrene / acrylic resin, styrene / maleic acid resin, and urethane resin. In consideration of compatibility with the particle core and the pigment dispersion resin, the water-soluble resin (A) is an acrylic resin. Styrene / acrylic resin and styrene / maleic acid resin are preferable. Furthermore, in consideration of the stable formation of particle nuclei, the water-soluble resin (A) further preferably has an aromatic skeleton.

When the water-soluble resin (A) is an acrylic resin, a styrene / acrylic resin, or a styrene / maleic acid resin, the water-soluble resin (A) is an ethylenically unsaturated monomer containing a carboxyl group-containing ethylenically unsaturated monomer. The body (a) is obtained by solution or bulk polymerization with a radical initiator. The aromatic skeleton can be introduced by copolymerizing an aromatic ethylenically unsaturated monomer.

As the ethylenically unsaturated monomer (a), for example,
Styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, m-methyl styrene, vinyl naphthalene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene Aromatic ethylenically unsaturated monomers of glycol acrylate, phenoxytetraethylene glycol methacrylate, phenoxyhexaethylene glycol acrylate, phenoxyhexaethylene glycol methacrylate, phenyl acrylate, phenyl methacrylate;
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;
Carboxylic acid such as maleic acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or alkenyl monoesters thereof, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid Group-containing ethylenically unsaturated monomers;
(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, N, N-diethylacrylamide, diacetoneacrylamide;
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;
Etc.

As the radical initiator used in the synthesis of the water-soluble resin (A), a known oil-soluble polymerization initiator can be used. For example, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl Organic peroxides such as peroxy (2-ethylhexanoate), 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.

When the water-soluble resin (A) is a urethane resin, it is not particularly limited, but it can be obtained by reacting a polyol and a polyisocyanate according to a conventionally known method.

  Typical examples of the polyol include polyester polyol, polyether polyol, and polycarbonate polyol.

  Examples of the polyester polyol include a polyester polyol obtained by condensation reaction of a polyol component and a dibasic acid component. Among the polyols, diols include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 3,3′-diene. Methylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, Examples of the polyol having three or more hydroxyl groups include glycerin, trimethylolpropane, pentaerythritol, and the like as dibasic acid components. Examples thereof include aliphatic or aromatic dibasic acids such as terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid and trimellitic acid, and anhydrides thereof. Moreover, the polyester polyol obtained by ring-opening polymerization of cyclic ester compounds, such as lactones, such as (epsilon) -caprolactone, poly ((beta) -methyl-gamma-valerolactone), and polyvalerolactone, is mentioned.

  Examples of the polyether polyol include tetrahydrofuran, or a polymer, copolymer or graft copolymer of alkylene oxide such as tetrahydrofuran, ethylene oxide, propylene oxide, butylene oxide, hexanediol, methylhexanediol, heptanediol, octanediol, or Those having two or more hydroxyl groups, such as polyether polyols obtained by condensation of these mixtures and polyether polyols which are propoxylated or ethoxylated, can be used.

  Examples of the polycarbonate polyol include those obtained by a reaction between a polyol and a carbonate compound such as dialkyl carbonate, alkylene carbonate, and diaryl carbonate. As a polyol which comprises a polycarbonate polyol, the polyol illustrated previously as a structural component of a polyester polyol can be used. Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate, examples of the alkylene carbonate include ethylene carbonate, and examples of the diaryl carbonate include diphenyl carbonate.

In addition, polybutadiene polyol, acrylic polyol, polysiloxane polyol, castor oil, and the like are also included.

These polyols may use only 1 type, or may use multiple types together.

Further, by using a polyol having a carboxyl group, the carboxyl group is introduced into the resin, and when neutralized with a basic compound, it can be dissolved or dispersed in an aqueous medium.

As a polyol component having a carboxyl group, for example,
Examples include dimethylol alkanoic acid such as dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, dihydroxypropionic acid, dihydroxybenzoic acid, etc. And dimethylolalkanoic acid.

  It is preferable that the acid value of water-soluble resin (A) is 100-250 mgKOH / g. If the acid value of the water-soluble resin (A) is less than 100 mgKOH / g, the dispersion stability deteriorates, and the core-shell resin fine particle dispersion cannot be stably synthesized. It may make it worse. On the other hand, when it exceeds 250 mgKOH / g, poor drying may occur, which may adversely affect the water friction resistance and water blocking resistance of the coating film. The acid value mentioned here means the number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of resin.

Furthermore, it is preferable that the weight average molecular weights of water-soluble resin (A) are 5000-20000, More preferably, it is 5000-15000. If the weight average molecular weight is less than 5,000, the dispersion stability of the resin fine particle dispersion is lowered, which may deteriorate the dispersion stability of the ink. On the other hand, when the weight average molecular weight exceeds 20000, the viscosity of the ink composition is remarkably increased, and also in this case, the dispersion stability may be deteriorated.

(Inadequate description. Enter manufacturer, solvent, column type, etc.)
Here, the weight average molecular weight (Mw) refers to a value in terms of polystyrene by GPC (gel permeation chromatography) measurement.
⇒ Details of the method are described in the examples section.

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.

As the water-soluble resin (A) having a carboxyl group, a commercially available product may be used as long as it satisfies the above-described composition conditions. As a commercial item, for example,
Acrylic resins such as X-300, VS-1029, VS-1057, TS-1316, VS-1028, TS-1315, RS-1190, VS-1030, VS-1220, etc. manufactured by Seiko PMC;
US-1071, X-1, RS-1193, VS-1259, TS-1318, YS-1274, VS-1047, RS-1191 manufactured by Seiko PMC;
BASF JONCRYL67, JONCRYL678, JONCRYL611, JONCRYL680, JONCRYL682, JONCRYL693, JONCRYL690, JONCRYL52J, JONCRYL57J, JONCRYL60J, JONCRYL96J, JONCRYL61J
Styrene acrylic resin such as
X-228, X-220, X-200, US-1243, X-205, X-210 manufactured by Seiko PMC
Styrene / maleic resin such as SMA1000, SMA2000, SMA1440, SMA2625 manufactured by Cray Valley, etc .;
Etc.

Next, the ethylenically unsaturated monomer (B) used in the present invention will be described. By polymerizing the ethylenically unsaturated monomer (B) under the protective colloid of the water-soluble resin (A), the particle core (core component) of the core-shell type resin particle dispersion (C) is formed.

The ethylenically unsaturated monomer (a) described above can be used for the ethylenically unsaturated monomer (B). When it is desired to increase the molecular weight by crosslinking the inside of the core, a crosslinkable ethylenically unsaturated monomer can be used.

Examples of the crosslinkable ethylenically unsaturated monomer include:
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;
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. It is not something. These can be used alone or in combination of two or more.

The ethylenically unsaturated monomer (B) is aromatic from the viewpoints of stability during particle nucleation, ease of impregnation of the water-insoluble epoxy compound into the particle nuclei, and excellent drying properties under low temperature drying. It preferably contains an ethylenically unsaturated monomer. Particle nuclei having an aromatic skeleton are excellent in stability in ink and are easily impregnated with a water-insoluble epoxy compound from the hydrophobic environment. Therefore, in the ink state, the reaction with the carboxyl group of the aqueous phase is suppressed, and the dispersion stability and pot life of the ink are improved. Moreover, since it becomes difficult to entrap moisture, the drying property of the coating film is also improved.

It is preferable to contain 20 to 70% by weight of the aromatic ethylenically unsaturated monomer in 100% by weight of the ethylenically unsaturated monomer (B). When the content of the aromatic ethylenically unsaturated monomer is less than 20% by weight, the effect of introducing the aromatic skeleton is small, the water-insoluble epoxy compound becomes easy to react, and the ink dispersion stability and pot life are reduced. There is a case. On the other hand, if it exceeds 70%, the compatibility between the core part and the shell part at the time of drying is lowered, film formation becomes insufficient, and the water friction resistance of the coating film may be deteriorated.

Furthermore, the ethylenically unsaturated monomer (B) preferably contains a keto group-containing unsaturated monomer.
When a keto group is introduced into the core-shell type resin fine particle dispersion (C) and a bifunctional or higher hydrazide compound is added to the ink, the keto group reacts with the hydrazide group during drying. In addition, some epoxy groups derived from the water-insoluble epoxy compound (E) also react with the hydrazide group. Therefore, a combination of these functional groups forms a tough coating film and improves water friction resistance. Furthermore, since keto groups are present on the treated surface of the film substrate, the adhesion to the substrate is also improved.

In the core-shell resin fine particle dispersion (C), it is preferable to introduce the keto group only into the core component. When it is introduced into the shell portion, it is crosslinked while the fusion does not proceed sufficiently, and film formation is hindered, and the water friction resistance of the coating film may be lowered.

The keto group-containing ethylenically unsaturated monomer is preferably contained in 1 to 5% by weight in 100% by weight of the ethylenically unsaturated monomer (B). If it is less than 1% by weight, the effect of crosslinking may not be sufficiently exhibited in the physical properties of the coating film. On the other hand, if it exceeds 5% by weight, crosslinking may occur while fusion does not proceed sufficiently, so that the film forming property may be deteriorated and the water friction resistance may be deteriorated.

  Examples of the keto group-containing ethylenically unsaturated monomer include diacetone (meth) acrylamide, acetoacetoxy (meth) acrylate, and the like.

The glass transition temperature (Tg) of the core of the core-shell type resin fine particle dispersion (C) is preferably in the range of -30 to 30 ° C. When the glass transition temperature of the core is less than −30 ° C., the coating film strength is insufficient, and the base material adhesion and water friction resistance of the coating film may decrease. On the other hand, even when the glass transition temperature exceeds 30 ° C., the wettability to the base material and the film-forming property may be reduced, and the base material adhesion and water friction resistance of the coating film may be reduced.

Said glass transition temperature (Tg) is the value calculated | required using DSC (differential scanning calorimeter). When the core-shell type resin fine particle dispersion is measured, the Tg of the core part and the shell part can be detected.

The weight average molecular weight of the core-shell resin fine particle dispersion (C) is preferably in the range of 200,000 to 500,000. If the weight average molecular weight is less than 200,000, the coating film strength may be insufficient, and the substrate adhesion and water friction resistance of the coating film may decrease. On the other hand, when it exceeds 500,000, the fusion of the core component and the shell component does not proceed sufficiently at low temperature drying, and the film-forming property is lowered, and the substrate adhesion of the coating film and the water friction resistance may not be sufficiently exhibited. is there.

  Water is mentioned as an aqueous medium used at the time of emulsion polymerization. A hydrophilic organic solvent can also be used in combination as long as it does not impair the stability during the synthesis of the resin fine particle dispersion.

The amount of the water-soluble resin (A) used in the synthesis of the core-shell type resin fine particle dispersion (C) is 40 to 150 parts by weight with respect to 100 parts by weight of the total of the ethylenically unsaturated monomer (B). Is preferred. If it is less than 40 parts by weight, the formation of particle nuclei becomes unstable during the synthesis of the resin fine particle dispersion. Moreover, since film forming property falls, there exists a possibility that the base-material adhesiveness of a coating film and water friction resistance may deteriorate. On the other hand, if it exceeds 150 parts by weight, the water friction resistance and water blocking resistance of the coating film may deteriorate due to poor drying.

  The polymerization initiator used in the emulsion polymerization is not particularly limited as long as it has the ability to initiate radical polymerization, and known oil-soluble polymerization initiators and water-soluble polymerization initiators 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.

When the resin fine particle dispersion used in the present invention is obtained by radical polymerization, a low molecular surfactant can be used in combination with the water-soluble resin (A) for the purpose of assisting stability. These can be used in combination as long as the ink physical properties are not adversely affected.

Examples of low molecular surfactants include:
Alkyl ethers (for example, Adalon KH-05, KH-10, KH-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap SR-10N, SR-20N manufactured by ADEKA Corporation, manufactured by Kao Corporation Latemul PD-104, etc.), sulfosuccinic acid ester type (commercially available products include, for example, Latemul S-120, S-120A, S-180P, S-180A, Kayo Co., Ltd., Elemiol JS-2, Sanyo Chemical Co., Ltd.) ), Alkylphenyl ethers or alkylphenyl esters (commercially available products include, for example, Aqualon H-2855A, H-3855B, H-3855C, H-3856, HS-05, HS-10 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) , HS-20, HS-30, Adeka Soap SDX-2 manufactured by ADEKA Corporation 2, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc.), (meth) acrylate sulfate ester system (commercially available products include, for example, Anne manufactured by Nippon Emulsifier Co., Ltd. Tox MS-60, MS-2N, Sanyo Kasei Kogyo Co., Ltd., Eleminol RS-30, etc.), phosphoric acid ester type (for example, H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA Co., Ltd. Anionic reactive emulsifiers such as rear soap PP-70);

Alkyl ether type (As commercial products, for example, Adeka Soap ER-10, ER-20, ER-30, ER-40 manufactured by ADEKA Corporation, Latemul PD-420, PD-430, PD-450 manufactured by Kao Corporation Etc.), alkylphenyl ethers or alkylphenyl esters (commercially available products include, for example, Aqualon RN-10, RN-20, RN-30, RN-50, ADEKA, Inc., Adekaria, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Soap NE-10, NE-20, NE-30, NE-40, etc.), (meth) acrylate sulfate ester (commercially available products include, for example, RMA-564, RMA-568, RMA-1114 manufactured by Nippon Emulsifier Co., Ltd. Nonionic reactive emulsifiers such as

Higher fatty acid salts such as sodium oleate, alkylaryl sulfonates such as sodium dodecylbenzene sulfonate, alkyl sulfate salts such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate salts such as sodium polyoxyethylene lauryl ether sulfate, Polyoxyethylene alkylaryl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate, alkyl sulfosuccinates such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof, Anionic non-reactive emulsification of polyoxyethylene distyrenated phenyl ether sulfates ;

Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether, sorbitan monolaurate, sorbitan mono Sorbitan higher fatty acid esters such as stearate and sorbitan trioleate, polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene such as polyoxyethylene monolaurate and polyoxyethylene monostearate Glycerin higher fatty acid ester such as higher fatty acid esters, oleic acid monoglyceride, stearic acid monoglyceride Le ethers, polyoxyethylene polyoxypropylene block copolymer, nonionic non-reactive emulsifier polyoxyethylene distyrenated phenyl ether;
Etc.

Next, the carbodiimide group-containing resin fine particle dispersion (D) used in the present invention will be described. The carbodiimide group-containing fine particle dispersion of the present invention is an emulsion type cross-linking agent, and can be obtained by modifying a hydrophilic group such as an ethylene oxide chain on a hydrophobic polycarbodiimide resin derived from a diisocyanate skeleton. The carbodiimide group reacts with the carboxyl group to improve the drying property of the coating film under low temperature drying. Furthermore, it is effective in improving water blocking resistance under low temperature drying due to its moderate elastic modulus derived from its functional group.

The polycarbodiimide skeleton in the carbodiimide group-containing resin fine particle dispersion (D) is obtained by a decarboxylation condensation reaction of a diisocyanate compound. Any diisocyanate compound can be used, but dicyclohexylmethane 4,4′-diisocyanate is preferable from the viewpoint of chemical stability, excellent reactivity, and optimum elastic modulus of the coating film.

The carbodiimide group-containing resin fine particle dispersion (D) can be synthesized by modifying a hydrophilic group to hydrophobic polycarbodiimide, but a commercially available product may be used.

As a commercial product of the carbodiimide group-containing resin fine particle dispersion (D), for example,
Carbodilite E-01, E-02, E-03A, E-04, etc. manufactured by Nisshinbo Chemical Co., Ltd. may be mentioned.

Next, the water-insoluble epoxy group-containing compound (E) used in the present invention will be described. The resin composition for water-based inks of the present invention contains a water-insoluble epoxy compound. The water-insoluble epoxy compound as used herein refers to an epoxy compound having a solubility in water of less than 1% at normal pressure and 20 ° C. The water-insoluble epoxy compound is added when preparing the ink composition. The water-insoluble epoxy group-containing compound (E) is impregnated inside the core of the core-shell resin fine particle dispersion (C) in the ink solvent. Therefore, the reaction between the water phase water-soluble resin (A) or the pigment-dispersed resin-derived carboxyl group and the epoxy group is suppressed, and the stability and pot life of the ink over time are improved. After drying, since the epoxy compound in the particle core diffuses into the coating film, the reaction with the carboxyl group is promoted and the water friction resistance is improved. Moreover, since it reacts also with the carboxyl group which exists in the surface of a nonpolar film base material, base-material adhesiveness also improves. Although the water-insoluble epoxy compound (E) is effective even if it is of a monofunctional type, it is preferably bifunctional or more from the viewpoint of improving the coating film strength. When a water-soluble epoxy compound is used, the dispersion stability of the ink and the pot life are extremely deteriorated.

As the water-insoluble epoxy group-containing compound (E), for example,
Monofunctional epoxy compounds such as alkyl glycidyl ether (alkyl carbon number C8-20), phenyl glycidyl ether, epoxidized α-olefin (olefin carbon number C8-20), limonene monooxide 3,4-epoxycyclohexanecarboxylic acid alkyl ester;
Neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, epoxy group-containing acrylic resin, epoxy group-containing styrene-acrylic resin, bisphenol-type epoxy resin, novolac-type epoxy resin, epoxidized vegetable oil, cyclohexane 1,1 of diglycidyl carboxylate, diglycidyl 4-cyclohexene-1,2-dicarboxylate, 4,5-epoxytetrahydrophthalic acid diglycidyl ester, pentaerythritol polyglycidyl ether, 2,2-bis (hydroxymethyl) -1-butanol 2-epoxy-4- (2-oxiranyl) cyclohexane adduct limonene dioxide, dicyclopentadiene diepoxide, hexanedioic acid bis (7-oxabicyclo [4.1 0] heptane-3-ylmethyl), 4-cyclohexanedimethanol bis (3,4-epoxycyclohexanecarboxylate), 4-phenylenedimethanol bis (3,4-epoxycyclohexanecarboxylate), 3'-4'-epoxy Bifunctional or higher functional epoxy group-containing compounds such as cyclohexylmethyl 3-4-epoxycyclohexanecarboxylate are exemplified.

Furthermore, the water-insoluble epoxy group-containing compound (E) preferably has an alicyclic epoxy group. Due to the more hydrophobic alicyclic structure, functional groups tend to exist inside the particle core. Furthermore, since the reactivity is also mild, it exhibits excellent performance in terms of ink dispersion stability and pot life. Moreover, it is safer than other epoxy compounds.

As the water-insoluble epoxy compound (E) having an alicyclic epoxy group, for example,
Limonene dioxide, dicyclopentadiene diepoxide, hexanedioic acid bis (7-oxabicyclo [4.1.0] heptan-3-ylmethyl), 4-cyclohexanedimethanol bis (3,4-epoxycyclohexanecarboxylate), Examples include 4-phenylenedimethanol bis (3,4-epoxycyclohexanecarboxylate), 3′-4′-epoxycyclohexylmethyl 3-4-epoxycyclohexanecarboxylate, and the like.

A commercially available product may be used as the water-insoluble epoxy compound (E).
Examples of commercially available water-insoluble epoxy compounds (E) include:
Epoxidized α-olefins such as Birocox 10, 12, 14, 16, 28 manufactured by Arkema, Inc .;
Alicyclic epoxy group-containing compounds such as Celoxide 2021P, 2081, 2000, Epolide GT401, EHPE3150CE (mixed product with epoxy resin) manufactured by Daicel Corporation;
Terpene oxides such as LMO / LDO manufactured by Arkema Co .;
Glycidyl group-containing acrylic resins such as NOF Corporation Marproof G-017581, Toagosei Co., Ltd., ALFON UG-4010;
Adeka resin EP-4000, EP-4005, 7001 and other alicyclic epoxy resins manufactured by ADEKA;
Etc.

The reaction between the water-insoluble epoxy compound and the core-shell type resin fine particle dispersion or the pigment dispersion resin improves the adhesion of the coating film to the substrate and the water friction resistance. It tends to reduce the blocking property. In the reaction between the carbodiimide group-containing resin fine particles and the core-shell type resin fine particle dispersion or pigment-dispersed resin, the water blocking resistance is improved. However, depending on the substrate, it is difficult to wet and the pot life is short, so that the coating film resistance is hardly exhibited. Therefore, it is difficult to satisfy the required physical properties even if each crosslinking system is used alone. When the water-insoluble epoxy compound and the carbodiimide group-containing resin fine particle dispersion are used in combination, the substrate adhesion and water friction resistance are dramatically improved, and the water blocking resistance is also greatly improved. In addition, the pot life is prolonged and the dispersion stability is good. These are considered to be due to a synergistic effect of the water-insoluble epoxy compound and the carbodiimide group-containing resin fine particle dispersion.

The water-based ink resin composition of the present invention can be used as a water-based ink composition, which will be described later, as well as a medium ink or an overcoat agent containing no pigment.

Next, the water-based ink composition of the present invention will be described. The water-based ink composition of the present invention is a water-based ink composition comprising the pigment, the pigment dispersion resin (F), water, a hydrophilic solvent, and the above-described resin composition for water-based ink.

The water-based ink resin composition is preferably used in an amount of 5 to 40% by weight, more preferably 10 to 30% by weight, in terms of solid content in 100% by weight of the water-based ink composition. If the resin composition for water-based ink is less than 5% by weight in terms of solid content, since the binding between the base material and the pigment and between the pigments becomes insufficient, the coating film properties (base material adhesion, water friction resistance) ) May decrease. In addition, if the resin composition for water-based ink exceeds 40% by weight in terms of solid content, the viscosity of the ink composition is remarkably increased, which may adversely affect the storage stability of the ink, cause poor drying, and the physical properties of the coating film. (Substrate adhesion, water friction resistance) may decrease.

As the pigment dispersion resin (F) used for pigment dispersion, any water-soluble resin can be used as long as it maintains ink stability and has pigment dispersion ability.

From the viewpoint of excellent pigment adsorbability and dispersion stability, the pigment dispersion resin (F) 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-maleic acid- (meth) acrylic acid An alkyl ester copolymer and a styrene-maleic acid half ester copolymer are preferable. 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 a commercial item of pigment dispersion resin (F), what was illustrated by water-soluble resin (A) can be used.

From the viewpoint of efficient adsorption to the pigment and compatibility with the core-shell resin fine particle dispersion (C), the pigment dispersion resin (F) preferably has an aromatic skeleton. The aromatic skeleton can be introduced by copolymerizing an aromatic-containing ethylenically unsaturated monomer, as in the case of the water-soluble resin (A).

The acid value of the pigment dispersion resin (F) is preferably in the range of 70 to 230 mgKOH / g. When the acid value is less than 70 mgKOH / g, the compatibility with the resin composition for ink is lowered during the film formation, the fusion is inhibited, and the water friction resistance of the coating film may be lowered. On the other hand, when it exceeds 230 mgKOH / g, poor drying may occur, and water friction resistance and water blocking resistance may be deteriorated.

The pigment dispersion resin (F) 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. If the pigment dispersion resin is less than 10 parts by weight with respect to 100 parts by weight of the pigment, the dispersion stability may decrease, and the dispersion stability and storage stability of the ink composition may deteriorate. 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.

The water-based ink composition of the present invention has a carbodiimide group derived from the carbodiimide group-containing resin fine particle dispersion (D) with respect to 1 mol of the carboxyl group derived from the core-shell resin fine particle dispersion (C) and the pigment dispersion resin (F). The range is preferably 0.1 to 0.5 mol. When the carbodiimide group is less than 0.1 mol, the effect of the carbodiimide group is not sufficiently exhibited, and the water blocking resistance of the coating film may be deteriorated. On the other hand, when it exceeds 0.5 mol, the dispersion stability of the ink composition may be deteriorated. Moreover, the wettability with respect to a base material worsens, and base material adhesiveness may deteriorate. Furthermore, it is preferable that the epoxy group derived from the water-insoluble epoxy compound (E) is in the range of 0.3 to 2 mol with respect to 1 mol of the carbodiimide group. When the epoxy group is less than 0.3 mol, the effect of the epoxy group is not sufficiently exhibited, and the water friction resistance and the substrate adhesion of the coating film may be lowered. On the other hand, when it exceeds 2 mol, an excessive water-insoluble epoxy compound may adversely affect the water blocking resistance of the coating film.

As the pigment, for example, an achromatic pigment such as carbon black, titanium oxide, calcium carbonate, or a chromatic organic pigment 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 ". 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 10-60 weight%.

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

In 100% by weight of the aqueous ink composition, the hydrophilic solvent 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 is less than 1% by weight, the printability 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 exceeds 10% by weight, the coating film may be poorly dried, and the physical properties of the coating film (base material adhesion, water friction resistance, blocking resistance) may be deteriorated. .

Examples of the hydrophilic solvent include monovalent alcohol solvents such as ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, and 2-methyl-2-propanol;
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. The hydrazide compound may be added at the resin composition stage, or may be added at the time of preparing the ink composition.

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 core-shell type resin fine particle dispersion (C) contains a keto group, it is preferable to add a water-soluble hydrazide compound for the purpose of forming a keto-hydrazide bridge. The amount of the hydrazide compound added is preferably 0.5 to 1.0 mol of hydrazide group with respect to 1.0 mol of keto group.

For the water-based 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, Inc. 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.

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 1.0% 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 coating film properties.

The water-based ink composition of the present invention exhibits excellent substrate adhesion and water friction resistance to film substrates such as polypropylene, polyethylene, and polyester even under low temperature drying. In addition, unlike water-permeable substrates such as paper, moisture is difficult to escape and even a film substrate with poor drying properties exhibits excellent water blocking resistance. Furthermore, the dispersion stability of the ink is good and the pot life is long. Therefore, the expansion to the base material of a film base material and the development to water-based flexographic printing and gravure printing, which require high-speed printing (low-temperature drying), can be greatly expected. Among the film bases, it exhibits excellent physical properties, especially for polyethylene terephthalate film, which is difficult to express coating film resistance. Not only the film substrate but also a conventional substrate such as a permeable substrate such as fine paper, art paper, and coated paper can be used for the purpose of improving the physical properties of the coating film.

In the drying step, any temperature can be applied as long as it does not adversely affect the substrate. In aqueous flexographic printing, the treatment is generally performed at a low temperature of 40 to 100 ° C. for 1 to 180 seconds. The dried printed matter is stored in a wound state.

  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 a refluxing device, 94.0 parts of butyl acetate was charged and the temperature was raised to 100 ° C. under nitrogen reflux while stirring. Next, in two dropping funnels, 40.0 parts of styrene, 28.0 parts of acrylic acid, 15.0 parts of methyl methacrylate, and 17.0 parts of n-butyl acrylate were dropped from one side over 3 hours. From the other side, 6.8 parts of dimethyl 2,2′-azobisisobutyrate was dissolved in 12.0 parts of butyl acetate and added dropwise over 4 hours. After completion of dropping, the reaction was further continued for 10 hours. After completion of the reaction, the solvent was removed by drying to obtain a solid water-soluble resin (A). The acid value of the water-soluble resin (A) was 204 mgKOH / g, and the weight average molecular weight was 10700.

[Production Examples 2 to 10]
Similarly to Production Example 1, a water-soluble resin (A) was synthesized with the composition shown in Table 1, and the solvent was removed to obtain a solid water-soluble resin (A).

[Production Example 11]
In a separate reaction vessel equipped with a stirrer, thermometer, and refluxer, charge 174.0 parts of P-2011 (Kuraray Polyester Polyol), 47.9 parts of dimethylolbutanoic acid, 128.6 parts of methyl ethyl ketone, and purge with nitrogen. The temperature was raised to 60 ° C. Furthermore, 78.1 parts of isophorone diisocyanate and 0.02 part of dibutyltin laurate were added, and the temperature was raised to 80 ° C. and reacted for 8 hours. The obtained water-soluble resin (A) had a weight average molecular weight of 8,900 and an acid value of 60 mgKOH / g.

[Acid value]
The number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of resin. The water-soluble resin (A) was calculated by performing potentiometric titration with a potassium hydroxide / ethanol solution according to the method described in JIS K2501.

[Weight average molecular weight]
The dried water-soluble resin (A) was dissolved in tetrahydrofuran to prepare a 0.1% solution, and the weight average molecular weight was measured using the following apparatus and measurement conditions.
Apparatus: HLC-8320-GPC system (manufactured by Tosoh Corporation)
Column; TSKgel-Super Multipore HZ-M0021488 4.6 mm ID × 15 cm × 3 (molecular weight measurement range 2,000 to about 2 million)
Elution solvent; Tetrahydrofuran standard substance; Polystyrene (Tosoh Corporation)
Flow rate: 0.6 mL / min, amount of sample solution used: 10 μL, column temperature: 40 ° C.

<Manufacture of core-shell type resin fine particle dispersion (C)>
[Production Example 12]
In a separate reaction vessel equipped with a stirrer, thermometer, two dropping funnels, and reflux, 40.0 parts of water-soluble resin (A) prepared in Production Example 1, 9.9 parts of 25% aqueous ammonia, ion exchange 145.7 parts of water was added and the temperature was raised to 60 ° C. with stirring to dissolve the water-soluble resin (A). (Ammonia water was added in an amount that neutralizes the carboxyl group of the water-soluble resin (A) 100%.) Further, the temperature was raised to 80 ° C. under nitrogen reflux. In two dropping funnels, a mixed solution of 20.0 parts of styrene, 18.0 parts of phenoxyethyl acrylate, 10.0 parts of n-butyl acrylate, and 52.0 parts of 2-ethylhexyl acrylate was dropped from one side over 2 hours. did. From the other side, 4.0 parts of a 20% aqueous solution of ammonium persulfate was added dropwise over 2 hours. After completion of the dropwise addition, the mixture was further reacted for 4 hours to obtain a core-shell type resin fine particle dispersion. The final solid content was adjusted to 45.0% with ion-exchanged water. About the obtained core-shell type resin fine particle dispersion, the average particle diameter, the weight average molecular weight, and the Tg of the core part were measured. The weight average molecular weight was measured by the same method as that for the water-soluble resin (A). The obtained core-shell resin fine particle dispersion had an average particle diameter of 84 nm, a weight average molecular weight of 420,000, and a glass transition temperature of the core part of −28 ° C.

[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.

[Glass transition temperature (Tg)]
The glass transition temperature (Tg) was measured by DSC (Differential Scanning Calorimeter TA Instruments). About 2 mg of a sample obtained by drying the resin fine particle dispersion is weighed on an aluminum pan, the aluminum pan is set on a DSC measurement holder, and the endothermic peak of the chart obtained under a temperature rising condition of 5 ° C./min is read. A transition temperature (Tg) was obtained.

[Production Examples 13 to 31]
Core-shell type resin fine particle dispersions (C) of Production Examples 13 to 31 were synthesized by the same method as Production Example 12 with the composition shown in Table 2. At this time, 25% aqueous ammonia was added so that the carboxyl group of the water-soluble resin (A) was neutralized 100%. For Production Example 31, since the polymer emulsifier does not have a carboxyl group and does not need to be neutralized, 25% aqueous ammonia was not added during dissolution. After completion of the synthesis, the final solid content of the core-shell resin fine particle dispersion (C) was adjusted to 45.0% with ion-exchanged water. For Production Examples 15, 19, and 26, adipic acid dihydrazide corresponding to 1/2 equivalent to the charged diacetone acrylamide was added during solid content adjustment. Physical properties such as weight average molecular weight were measured before adding adipic hydrazide.

The compounds listed in Table 2 are shown below.
SMA2000 (made by Cray Valley, styrene / maleic anhydride resin, Mw7500, acid value 350)
M-205 (Kuraray Reactive Group-Containing Polyvinyl Alcohol)

<Production of water-based ink composition>

<Manufacture of pigment dispersion resin (F)>
[Production Example 32]
In a separate reaction vessel equipped with a stirrer, thermometer, two dropping funnels, and reflux, 94 parts of methyl isobutyl ketone was charged, and the temperature was raised to 100 ° C. under nitrogen reflux while stirring. Next, in two dropping funnels, from one side, 20.0 parts of styrene, 5.0 parts of α-methylstyrene, 15.0 parts of acrylic acid, 30.0 parts of methyl methacrylate, 30.0 parts of n-butyl acrylate Was added dropwise over 3 hours. From the other side, 5 parts of dimethyl 2,2′-azobisisobutyrate was dissolved in 5.0 parts of methyl isobutyl ketone and added dropwise over 4 hours. After completion of dropping, the reaction was further continued for 10 hours. After the reaction was completed, the solvent was removed by drying to obtain a solid pigment dispersion resin (F). The acid value and the weight average molecular weight were measured by the same method as that for the water-soluble resin (A). The obtained pigment dispersion resin (F) had an acid value of 111 mgKOH / g and a weight average molecular weight of 10,300. To this pigment dispersion resin (F), 25% ammonia water is added so that the carboxyl groups are neutralized 100%, and ion exchange water is further added, and 28.0 of the pigment dispersion resin (F) is heated and stirred. % Aqueous solution was obtained.

[Production Examples 33 to 38]
In the same manner as in Production Example 32, the pigment dispersion resins (F) of Production Examples 33 to 38 were synthesized with the composition shown in Table 3 to prepare a 28.0% aqueous solution.

<Production of concentrated pigment dispersion>

[Production Example 39]
<Production of concentrated white pigment dispersion>
67.5 parts of pigment [Taipeke CR80 made by Ishihara Sangyo Co., Ltd.], 25.0 parts of pigment dispersant aqueous solution (solid content 28%) of Production Example 32, 2.1 parts of ion-exchanged water, surface conditioner [Surfinol 420 Nissin Chemical Co., Ltd.] 0.4 parts was dispersed with a paint conditioner for 2 hours to obtain a concentrated white pigment dispersion.

[Production Examples 40 to 45]
A concentrated white pigment dispersion was prepared in the same manner as in Production Example 39 with the formulation shown in Table 4.

[Production Example 46]
<Manufacture of concentrated indigo pigment dispersion>
34.2 parts of a pigment [Lionol Blue FG7330 manufactured by Toyocolor Co., Ltd.], 22.0 parts of an aqueous pigment-dispersed resin solution (solid content 28%) of Production Example 32, 26.4 parts of ion-exchanged water, a 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 indigo pigment dispersion.

[Production Examples 47 to 52]
A concentrated indigo pigment dispersion was prepared in the same manner as in Production Example 46 with the formulation shown in Table 5.

<Preparation of water-based ink resin composition>
[Example 1]
76.2 parts of the core-shell type resin fine particle dispersion (C) produced in Production Example 12, 11.9 parts of carbodilite E-01 (Nisshinbo Chemical Co., Ltd. carbodiimide group-containing resin fine particle dispersion solid content 40%), 2-ethylhexylglycidyl 11.9 parts of ether was added and stirred and mixed to obtain the desired resin composition for water-based ink.

[Examples 2-29 and Comparative Examples 1-12]
Resin compositions for aqueous inks of Examples 2 to 29 and Comparative Examples 1 to 12 were obtained in the same manner as in Example 1 with the blending compositions shown in Tables 6 and 7.

The compounds listed in Table 6 are shown below.
Carbodilite E-01 (Nisshinbo Chemical Co., Ltd. Carbodiimide group-containing emulsion Carbodiimide equivalent 425)
Carbodilite E-02 (Nisshinbo Chemical Co., Ltd. Carbodiimide group-containing emulsion Carbodiimide equivalent 445)
Carbodilite E-03A (Nisshinbo Chemical Co., Ltd. Carbodiimide group-containing emulsion Carbodiimide equivalent 365)
Marproof G-017581 (manufactured by NOF Corporation glycidyl group-containing acrylic resin Mw10000 epoxy equivalent 240)
LMO / LDO (mixture of limonene monooxide and limonene dioxide produced by Arkema LMO / LDO = 7/3)
EHPE3150CE (1,2-epoxy-4- (2-oxiranyl) of 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and 2,2-bis (hydroxymethyl) -1-butanol manufactured by Daicel Corporation Mixture of cyclohexane adduct epoxy equivalent 152)

The compounds listed in Table 7 are shown below. (Excluding those that overlap with Table 6)
Denacol EX-850 (manufactured by Nagase ChemteX Corporation diethylene glycol diglycidyl ether epoxy equivalent 122)

<Preparation of water-based ink composition>
[Example 30]
47.5 parts of the concentrated white pigment dispersion of Production Example 39 and 5.0 parts of Chemipearl W500 (polyolefin aqueous dispersion manufactured by Mitsui Chemicals) with respect to 42.0 parts of the resin composition for water-based ink obtained in Example 1 Then, 4.0 parts of n-propanol part, 1.0 part of butyl diglycol and 0.5 part of ion-exchanged water were added and then kneaded to obtain a white aqueous ink composition.

[Examples 31-58 and Comparative Examples 13-24]
It was prepared in the same manner as in Example 30 with the composition shown in Table 8 and Table 9, and white aqueous ink compositions of Examples 31 to 58 and Comparative Examples 13 to 24 were obtained.

The compounds listed in Table 8 are shown below.
Chemipearl W-500 (Mitsui Chemicals polyolefin water dispersion solid content 40%)

[Example 59]
41.5 parts of the concentrated indigo pigment dispersion of Production Example 46 and Chemipearl W500 (polyolefin water dispersion manufactured by Mitsui Chemicals) 4.5% of the resin composition for water-based ink obtained in Example 1 Part, n-propanol part 3.0 part, butyl diglycol 1.0 part and ion-exchanged water 8.0 part were added and then kneaded to obtain an indigo water-based ink composition.

[Examples 60 to 87 and Comparative Examples 25 to 36]
The blending compositions shown in Table 10 and Table 11 were prepared in the same manner as in Example 59 to obtain Examples 60 to 87 and Comparative Examples 25 to 36 indigo water-based ink compositions.

<Evaluation of water-based ink composition>
The aqueous ink composition prepared above was evaluated for dispersion stability (presence of separation, precipitation, fluidity) over time. Further, the water-based ink composition was applied twice to a treated PET film (Toyobo polyester film E-5100, thickness 12 μ) using Flexiproof 100 (anilox roller 70 lines / cm), and then heated in an oven at 60 ° C. After heat treatment for about minutes, the untreated PET film was overlaid from above so that the coated surface was not exposed to air. After this coating film for evaluation was stored at 40 ° C. for 1 day in a constant temperature and humidity chamber, the substrate adhesion, water friction resistance, and water blocking resistance were evaluated. (Water blocking resistance is a blocking test in which water is contained on the coated surface, and is more susceptible to drying defects and components eluted into water than normal blocking tests.) This was done for the later ink composition. The pot life was evaluated from the applicability of the ink composition after the passage of time and the physical properties of the coating film (substrate adhesion, water rub resistance, water blocking resistance). Tables 8 to 11 show the results.

[Dispersion stability]
About the water-based ink composition, the presence or absence of separation, precipitate, and fluidity was visually confirmed over time. There was no separation or precipitation, and the fluid state was stabilized. A state where separation or precipitation occurs and no fluidity is regarded as unstable.
The evaluation criteria are as follows. (Practical level is more than ○ △)
A: Stable until 24 hours after preparation.
○: Stable until 16 hours after preparation.
○ △: Stable until 12 hours after preparation.
Δ: Stable until 8 hours after preparation.
X: Stable until 4 hours after preparation.

[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 ○: Ink peeling slightly (less than 5%)
○ △: Some ink peeling (5% or more, less than 10%)
Δ: Ink peeling (10% or more, less than 50%)
×: Ink peeling is considerable (50% or more)

[Water friction resistance]
After immersing the evaluation coating film in water, the surface of the coated coating film was reciprocated 40 times with a load of 800 g using a Gakushin Tester (manufactured by Tester Sangyo Co., Ltd.) using Kanakin (JIS L 0803) as a friction element. 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 1%)
○ △: Some ink peeling (1% or more, 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 was dropped on the coated surface, an untreated PET film was overlaid, a load of 1 kg / cm ² was applied, and the coating film was left at 40 ° C. for 24 hours. Then, the coating film for evaluation was taken out and the presence or absence of show-through was confirmed. The water blocking resistance was evaluated from the ratio of the offset area.
The evaluation criteria are as follows. (Practical level is more than ○ △)
◎: No sound when peeling, no set-off ○: Sound when peeled, but no set-off ○ △: The ink is slightly show-through on the back (less than 1%)
△; Ink is slightly on the back (1% or more and less than 5%)
X: Ink is showing through on the back (5% or more)

[Pot life]
About the water-based ink composition of time, pot life was evaluated from the coating property by the above-mentioned printing press, and coating-film physical property (base-material adhesiveness, water friction resistance, water blocking resistance). The evaluation criteria are as follows (practical level is more than ○ △)
A: Applicable up to 24 hours after preparation and expresses coating film properties equivalent to those of ink immediately after preparation. O; Applicable up to 16 hours after preparation and expresses coating film properties equivalent to that of ink immediately after preparation. .
◯: Applicable up to 12 hours after preparation and exhibiting coating film properties equivalent to ink immediately after preparation.
Δ: Applicable up to 8 hours after preparation and expresses coating film properties equivalent to ink immediately after preparation ×: Applicable up to 4 hours after preparation and expresses coating film properties equivalent to ink immediately after preparation

As shown in Table 8 and Table 11, white aqueous ink compositions (Examples 30 to 58) and indigo water-based ink compositions (Examples 59 to 87) using the resin compositions for aqueous inks of Examples 1 to 29. ) Has good dispersion stability and was confirmed to exhibit excellent substrate adhesion, water friction resistance, and water blocking resistance with respect to the film substrate even under low temperature drying. The pot life was a result that could be used without any problem for at least 8 hours after preparation. All of these items satisfy practically possible levels. On the other hand, white aqueous ink compositions (Comparative Examples 13 to 24) and indigo water-based ink compositions (Comparative Examples 25 to 36) using the resin compositions for aqueous inks of Comparative Examples 1 to 12 have dispersion stability, coating The film physical properties (base material adhesion, water rub resistance, water blocking resistance), and pot life have problems, and the result does not satisfy the practical level.

Claims (8)

A core-shell resin fine particle dispersion (C) obtained by emulsion polymerization of an ethylenically unsaturated monomer (B) in an aqueous medium using a water-soluble resin (A) having a carboxyl group as a polymer emulsifier;
A carbodiimide group-containing resin fine particle dispersion (D);
A water-based ink resin composition comprising a water-insoluble epoxy group-containing compound (E). The resin composition for water-based ink according to claim 1, wherein the water-insoluble epoxy group-containing compound (E) has an alicyclic epoxy group. The resin composition for water-based inks according to claim 1 or 2, wherein the glass transition temperature of the core part of the core-shell type resin fine particle dispersion (C) is -30 to 30 ° C. The resin composition for water-based ink according to any one of claims 1 to 3, wherein the core-shell resin fine particle dispersion (C) has a weight average molecular weight of 200,000 to 500,000. The resin composition for water-based ink according to any one of claims 1 to 4, wherein the amount of the water-soluble resin (A) is 40 to 150 parts by weight with respect to a total of 100 parts by weight of the ethylenically unsaturated monomer (B). A water-based ink composition comprising the pigment, the pigment-dispersed resin (F), water, a hydrophilic solvent, and the water-based ink resin composition according to any one of claims 1 to 5. The carbodiimide group derived from the dispersion (D) is in the range of 0.1 to 0.5 mol with respect to 1 mol of the carboxyl group derived from the dispersion (C) and the resin (F),
The water-based ink composition according to claim 6, wherein the epoxy group derived from the compound (E) is in the range of 0.3 to 2 mol relative to 1 mol of the carbodiimide group derived from the dispersion resin (D). The water-based ink composition according to claim 6 or 7, which is used for flexographic printing or gravure printing.