JP2021024970A - Active energy ray-curable lithographic ink, method for producing a printed matter using the same, and varnish for active energy ray-curable lithographic ink - Google Patents

Abstract

To provide a varnish for an active energy ray-curable lithographic ink which suppresses misting at the time of printing, has excellent scumming resistance, and has improved storage stability, and to provide an active energy ray-curable lithographic ink.SOLUTION: There is provided a varnish for an active energy ray-curable lithographic ink including: (1) a resin which is a copolymer of a monomer containing (a) a styrene, (b) a (meth) acrylic alkyl ester, and (c) a hydrophilic group-containing vinyl monomer, and which has an acid value of 150 mgKOH/g or more and 250 mgKOH/g or less; (2) a compound having an ethylenically unsaturated group; and (3) one or more kinds of compound selected from a nitroso compound and a polyfunctional amine compound, and there is also provided an active energy ray-curable lithographic ink containing the varnish.SELECTED DRAWING: None

Description

The present invention relates to an active energy ray-curable flat plate ink, a method for producing a printed matter using the same, and a varnish for an active energy ray-curable flat plate ink.

From the viewpoint of dealing with environmental problems and preserving the working environment in recent years, efforts are underway to reduce VOCs by significantly reducing the use of volatile petroleum-based solvents in various printing fields.

Planographic printing is a printing method that is widely used as a system for supplying printed matter at high speed, in large quantities, and at low cost, and includes lithographic printing with water and lithographic printing without water.

In lithographic printing with water, dampening water containing a volatile solvent is used at the time of printing in order to repel the ink, and there are problems in terms of work and environment such as generation of harmful waste liquid and VOC. On the other hand, in waterless lithographic printing, since the ink is repelled by silicone rubber or fluororesin instead of dampening water, dampening water is not required, which is an excellent printing method in terms of work and environment.

However, since a large amount of petroleum-based solvent is also used in general lithographic printing ink, it is desired to make the ink water-based or solvent-free. The use of printing ink, which can be instantly cured by irradiating it with active energy rays such as ultraviolet rays, is expanding in many fields due to its equipment, safety, environment, and high productivity. In lithographic printing as well, the development of active energy ray-curable ink is underway.

In Patent Document 1, a resin obtained by copolymerizing styrenes, (meth) acrylic acid alkyl ester and a hydrophilic group-containing vinyl monomer is used, and printing is performed by using an active energy ray-curable water-based flat plate ink. Inventions that reduce the misting of ink at the time are described.

In Patent Document 2, a resin having a hydrophilic group and a polyfunctional (meth) acrylate having a hydroxyl group are used to prepare an active energy ray-curable lithographic ink, so that the ink aggregates under high shear during printing. An invention is described in which the ground stain resistance is improved by increasing the force and suppressing the adhesion of ink to the non-image area of the printing plate.

Japanese Patent No. 5598648 International Publication No. 2018/163942

However, when waterless lithographic printing is performed with the water-based lithographic printing ink disclosed in Patent Document 1, there is a problem that misching occurs. Further, there is a problem that the ground stain resistance at the time of printing is poor. The lithographic printing ink disclosed in Patent Document 2 has good ground stain resistance, but has a problem that misting suppression is still insufficient and storage stability is low.

Therefore, in the present invention, an active energy ray-curable lithographic ink that overcomes the problems of the prior art, suppresses misting during printing, has excellent ground stain resistance, and has improved storage stability, and a printed matter using the same. Provided are a manufacturing method and a varnish for active energy ray-curable lithographic ink.

The present invention is a copolymer of (1) (a) styrenes, (b) (meth) acrylic acid alkyl ester and (c) a monomer containing a hydrophilic group-containing vinyl monomer, and has an acid value of 150 mgKOH / g. Active energy ray-curable type containing any one or more compounds selected from a resin having a concentration of 250 mgKOH / g or less, (2) a compound having an ethylenically unsaturated group, (3) a nitroso compound and a polyfunctional amine compound. The present invention relates to flat plate ink, a method for producing a printed matter using the flat plate ink, and a varnish for active energy ray-curable flat plate ink.

According to the present invention, an active energy ray-curable lithographic ink that suppresses misting during printing, has excellent ground stain resistance, and has improved storage stability, a method for producing a printed matter using the same, and active energy ray curing. Provide varnish for lithographic ink.

Hereinafter, the present invention will be specifically described.

The active energy ray-curable slab ink varnish and the active energy ray-curable slab ink according to the present invention include (1) (a) styrenes, (b) (meth) acrylic acid alkyl ester and (c) hydrophilic groups. It is a copolymer of a monomer containing a vinyl monomer and contains a resin having an acid value of 150 mgKOH / g or more and 250 mgKOH / g or less (hereinafter referred to as (1) resin).

Examples of (a) styrenes include styrene, α-methylstyrene, and styrene compounds having at least one alkyl group having 1 to 4 carbon atoms in the aromatic ring. (1) The varnish for active energy ray-curable flat plate ink containing a resin and the active energy linear curable flat plate ink are provided with elasticity derived from the aromatic ring skeleton to be imparted to the varnish and the ink, and low-spinning ink can be obtained. Misting during printing can be suppressed. (1) If the content of (a) styrenes in the resin is less than 40% by weight, varnish and ink having high spinnability will be formed and misting will occur. Further, (a) when the content of styrenes is 65% by weight or more, the solubility in the ethylenically unsaturated compound becomes poor, so that the viscosity of the varnish and the ink becomes high, and the dispersibility of the pigment is lowered and appropriate. Problems such as unobtainable print density and storage stability problems such as resin precipitation during storage of varnish and ink occur. (1) The styrenes (a) contained in the resin are preferably contained in an amount of 45% by weight or more, preferably less than 60% by weight, and more preferably less than 55% by weight.

(1) The content of (a) styrenes contained in the resin is determined by gel permeation chromatography (GPC) from the varnish for active energy ray-curable slab ink or the active energy ray-curable slab ink containing the varnish. After eluting the resin, it can be measured by NMR analysis.

In the resin, the (b) (meth) acrylic acid alkyl ester includes methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth). Examples thereof include -2-ethylhexyl acrylate, isononyl (meth) acrylate, and dodecyl (meth) acrylate, and these can be used alone or in combination of two or more.

In the resin (1), the monomer containing (c) a hydrophilic group-containing vinyl monomer is a vinyl monomer having a carboxyl group, a sulfo group, a phosphoric acid group, a hydroxyl group and the like as hydrophilic groups. Carboxyl group-containing vinyl monomers are preferable in that the dispersibility of the pigment is good and the cohesive force of the ink is increased due to the interaction between the carboxyl groups. Specific examples thereof include (meth) acrylic acid and (meth) acrylic acid dimer, and these can be used alone or in combination of two or more.

(1) The acid value of the resin is 150 mgKOH / g or more and 250 mgKOH / g or less. (1) By increasing the cohesive force of the resin, the cohesive force of the ink under high shear during printing is enhanced, the ink adhesion to the non-image area of the printing plate is suppressed, and the ground stain resistance is improved. , 150 mgKOH / g or more, preferably 170 mgKOH / g or more, and more preferably 190 mgKOH / g or more. On the other hand, (1) the cohesive force of the resin becomes too high, and it is 250 mgKOH / g or less and 230 mgKOH / g or less in order to suppress cohesion / precipitation in the varnish or thickening of the ink over time. It is preferably 210 mgKOH / g or less, and more preferably 210 mgKOH / g or less. In addition, (1) the acid value of the resin can be determined in accordance with the neutralization titration method of Section 3.1 of the test method of JIS K 0070: 1992.

(1) The weight average molecular weight of the resin is preferably 17,000 or more, more preferably 18,000 or more, and more preferably 19,000 or more in order to give appropriate viscosity and fluidity to the ink. Is even more preferable. Further, in order to suppress aggregation / precipitation in the varnish or thickening of the ink over time and stabilize the ink, the content is preferably 30,000 or less, more preferably 25,000 or less, 22 It is more preferably 000 or less.

The weight average molecular weight can be obtained by measuring in terms of polystyrene using GPC.

The content of (1) resin contained in the varnish for active energy ray-curable flat plate ink of the present invention is (1) resin, (2) compound having an ethylenically unsaturated group, and (3) nitroso compound and many. When the total number of functional amine compounds is 100 parts by mass, it is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further 25 parts by mass or more in terms of obtaining a viscosity with good handleability. preferable. Further, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 40 parts by mass or less in terms of suppressing aggregation and precipitation in the varnish over time and stabilizing the varnish.

The content of (1) resin contained in the active energy ray-curable flat plate ink of the present invention is 5 parts by mass or more in order to obtain the viscosity of the ink required for printing when the total amount of the ink is 100 parts by mass. It is preferably 10 parts by mass or more, more preferably 12 parts by mass or more. Further, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, still more preferably 20 parts by mass or less, in terms of suppressing thickening of the ink with time and stabilizing it.

(1) The method for polymerizing the resin is not particularly limited. Preferably, it is a method of radically polymerizing a monomer component using a radical polymerization initiator in the presence of a solvent or a chain transfer agent, if necessary.

(1) When a solvent is used in the polymerization of the resin, known ones such as an aromatic hydrocarbon solvent, a ketone solvent, an ether solvent, an alcohol solvent, and an ester solvent can be used. Specific examples thereof include toluene, xylene, ethylbenzene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, butyl acetate and ethyl acetate. In addition, one of these may be used alone, or two or more thereof may be used in combination. The solvent is preferably used in the range of 50 to 300 parts by mass with respect to 100 parts by mass of all the monomer components.

The radical polymerization initiator is not particularly limited, and known substances such as inorganic peroxides, organic peroxides, and azo compounds can be used. Specifically, inorganic peroxides such as ammonium persulfate and potassium persulfate, benzoyl peroxide, t-butylperoxyacetate, 2,2-di- (t-butylperoxy) butane, and t-butylperoxybenzoate. , N-Butyl 4,4-di- (t-butylperoxy) valerate, di- (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5 -Dimethyl-2,5,-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, diisopropylbenzene hydroperoxide, p-menthan hydroperoxide, 1,1, Organic peroxides such as 3,3,-tetramethylbutylhydroperoxide, cumenehydroperoxide, t-butylhydroperoxide and t-butyltrimethylsilyl peroxide, 1-[(1-cyano-1-methylethyl). Azo] formamide, 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis (N-cyclohexyl-2-methylpropionamide) and 2,2'-azobis (2,4) , 4-trimethylpentane), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), etc. Azo-based compounds and the like can be mentioned. In addition, one of these may be used alone, or two or more thereof may be used in combination. The radical polymerization initiator is preferably used in the range of 0.1 to 30 parts by mass with respect to 100 parts by mass of all the monomer components.

The active energy ray-curable slab ink and the varnish for active energy ray-curable slab ink according to the present invention contain (2) a compound having an ethylenically unsaturated group.

(2) A compound having an ethylenically unsaturated group is a component that polymerizes with radicals generated from a photopolymerization initiator described later to increase the molecular weight, and is a component called a monomer, an oligomer, or the like.

The monomer has an ethylenically unsaturated group and is a component that polymerizes to increase the molecular weight as described above, but in the state before polymerization, it is often a liquid component having a relatively low molecular weight, (1). It is also used as a solvent for dissolving a resin to form a varnish, and for adjusting the viscosity of an ink composition. Examples of the monomer include a monofunctional monomer having one ethylenically unsaturated group in the molecule and a bifunctional or higher monomer having two or more ethylenically unsaturated groups in the molecule. Bifunctional or higher functional monomers are preferably used because they can crosslink molecules to each other when the ink composition is cured, thus increasing the curing rate and forming a strong film.

Bifunctional or higher-functional monomers include trimethylolpropane triacrylate (TMPTA), trimethylolpropane tetraacrylate (DITMPTA), pentaerythritol tetra (meth) acrylate, dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate ethylene oxide adduct. , Glycerin propoxytriacrylate (GPTA), hexanediol diacrylate (HDDA; bifunctional) and the like. These bifunctional or higher functional monomers can be used alone or in combination of two or more.

The oligomer is a component that polymerizes to increase the molecular weight as described above, but since it is a component having a relatively high molecular weight, it is also used for the purpose of imparting appropriate viscosity and elasticity to the ink composition. Examples of the oligomer include epoxy-modified (meth) acrylate and rosin-modified epoxy, which are exemplified by the ester of a hydroxyl group and (meth) acrylic acid generated after the epoxy group contained in an epoxy compound such as an epoxy resin is opened with an acid or a base. Esters of polyester-modified (meth) acrylates exemplified as esters of acrylates, terminal hydroxyl groups of polycondensation polymers of dibasic acid and diol and (meth) acrylic acid, and ester of terminal hydroxyl groups of polyether compounds and (meth) acrylic acid. Examples thereof include polyether-modified (meth) acrylates exemplified by, and urethane-modified (meth) acrylates exemplified by esters of terminal hydroxyl groups and (meth) acrylic acid in a condensate of a polyisocyanate compound and a polyol compound. ..

Among these compounds having ethylenically unsaturated groups, pentaerythritol tetra (meth) acrylate ethylene oxide is low in viscosity, can be widely adjusted in varnish viscosity, and (1) has excellent resin solubility. Additives can be preferably used.

The number of ethylene oxide chains in one molecule of the pentaerythritol tetra (meth) acrylate ethylene oxide adduct is 4 or more in order to (1) improve the solubility of the resin and suppress aggregation and precipitation in the varnish over time. Preferably, 6 or more is more preferable, and 8 or more is further preferable. On the other hand, (1) a significant decrease in varnish viscosity due to the resin being too soluble and a decrease in sensitivity of the ink using the varnish to active energy rays can be suppressed, so 35 or less is preferable, and 25 or less is preferable. More preferably, 15 or less is further preferable. There - _{(C 2} H 4 O-) units continuously Herein, the oxide chain number in one molecule, refers to _{(-C 2} H 4 O-) that the total number of units in the _molecule, However, other linking groups may be present between non-contiguous (-C ₂ H _{4 O-) units.} The number of ethylene oxide chains in one molecule of the pentaerythritol tetra (meth) acrylate ethylene oxide adduct can be measured by liquid chromatography / mass spectrometry (LC / MS). By LC / MS measurement of the varnish, the structure of the compound having an ethylenically unsaturated group can be identified from the mass spectrum and the mass spectrum of the product ion. When the compound having an ethylenically unsaturated group is a pentaerythritol tetra (meth) acrylate ethylene oxide adduct, the number of ethylene oxide chains in one molecule can be calculated from the molecular weight derived from the mass spectrum.

In the case of ink, dichloromethane is added to extract the organic component, and the extract is separated into dichloromethane-soluble matter and insoluble matter by ultracentrifugation, and the dichloromethane-soluble matter is used for the above-mentioned LC / MS measurement. By providing this, the number of ethylene oxide chains in one molecule can be calculated.

The content of the compound having an ethylenically unsaturated group contained in the varnish for active energy ray-curable flat plate ink according to the present invention is (1) a resin and (2) a compound having an ethylenically unsaturated group. , And (3) when the total of the nitroso compound and the polyfunctional amine compound is 100 parts by mass, 30 to 90 parts by mass is preferable, 40 to 85 parts by mass is more preferable, and 50 to 80 parts by mass is further preferable. When the content of the compound having an ethylenically unsaturated group is in the above range, it is possible to achieve both a viscosity with good handleability and storage stability.

The content of the compound having an ethylenically unsaturated group contained in the active energy ray-curable flat plate ink according to the present invention is preferably 30 to 60 parts by mass when the total amount of the ink is 100 parts by mass. 35 to 55 parts by mass is more preferable, and 40 to 50 parts by mass is further preferable. When the content of the compound having an ethylenically unsaturated group is in the above range, both good curability and printability can be achieved.

The active energy ray-curable slab ink and the varnish for active energy ray-curable slab ink according to the present invention contain any one or more compounds selected from (3) nitroso compounds and polyfunctional amine compounds.

(3) A nitroso compound and a polyfunctional amine compound (hereinafter referred to as (3) compound) act as a compatibilizer that uniformly diffuses and dissolves (1) a resin, dramatically improving the storage stability of varnish and ink. Can be made to. In particular, it has an excellent effect on (1) resins having a high cohesive power and a high acid value.

The (3) compound inhibits the interaction related to the aggregation of the resins such as (1) hydrogen bond and ionic bond generated by the hydrophilic group of the resin, and (2) is a compound having an ethylenically unsaturated group (1). The resin can be stabilized in a uniform diffused or dissolved state.

(3) Specific examples of the compound include 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) and 2,2,6,6-tetramethylpiperidine-1-oxyl. N-oxyl compounds such as (TEMPO), nitroso compounds such as aluminum N-nitrosophenylhydroxylamine and N-nitrosodiphenylamine, Jeffamine T403 (trifunctional polyetheramine manufactured by Tomoe Kogyo Co., Ltd.), Jeffamine D400 (Tomoe). Examples thereof include polyfunctional amine compounds such as (bifunctional polyetheramine manufactured by Kogyo Co., Ltd.) and Jeffamine D230 (bifunctional polyetheramine manufactured by Tomoe Kogyo Co., Ltd.).

(3) The compound is preferably a nitroso compound because of its low cost and less coloring of the varnish even when added.

More preferably, it is 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, and aluminum N-nitrosophenylhydroxylamine.

The content of the (3) compound contained in the varnish for active energy ray-curable flat plate ink according to the present invention is (1) a resin, (2) a compound having an ethylenically unsaturated group, and (3) a nitroso compound. And when the total of the polyfunctional amine compounds is 100 parts by mass, 0.01 parts by mass or more in terms of (1) suppressing aggregation and precipitation of the resin in the varnish over time and improving storage stability. Is preferable, 0.05 parts by mass or more is more preferable, and 0.1 parts by mass or more is further preferable. On the other hand, (1) 0.4 parts by mass or less is preferable, 0.35 parts by mass or less is more preferable, and 0.3 parts by mass or less is preferable in terms of suppression of a significant decrease in viscosity due to promotion of compatibility of the resin and cost. More preferred.

The content of the compound (3) contained in the active energy ray-curable flat plate ink according to the present invention suppresses thickening of the ink over time when the total amount of the ink is 100 parts by mass, and is stable in storage. From the viewpoint of improving the properties, 0.005 parts by mass or more is preferable, 0.025 parts by mass or more is more preferable, and 0.05 parts by mass or more is further preferable. On the other hand, from the viewpoint of maintaining appropriate viscosity and fluidity, 0.2 parts by mass or less is preferable, 0.18 parts by mass or less is more preferable, and 0.15 parts by mass or less is further preferable.

In the varnish for active energy ray-curable flat plate ink according to the present invention, (2) a polymerization inhibitor may be added in order to suppress cross-linking / polymerization of a compound having an ethylenically unsaturated group and improve storage stability. preferable. Specific examples of the polymerization inhibitor include hydroquinone, hydroquinone monoesteride, phenothiazine, pt-butylcatechol, N-phenylnaphthylamine, 2,6-di-t-butyl-p-methylphenol, chloranyl, and the like. Pyrogallol and the like can be mentioned. The amount of the polymerization inhibitor added is good when the total of (1) resin, (2) compound having an ethylenically unsaturated group, and (3) nitroso compound and polyfunctional amine compound is 100 parts by mass. From the viewpoint of obtaining stability, 0.001 part by mass or more and 0.5 part by mass or less is preferable.

The method for producing the varnish for active energy ray-curable lithographic ink according to the present invention will be described below. In the varnish for active energy ray-curable flat plate ink of the present invention, (1) resin, (2) ethylenically unsaturated group-containing compound, (3) compound, and other components are added at 50 to 150 ° C. as necessary. It is obtained by warm-dissolving and then cooling to room temperature.

The active energy ray-curable flat plate ink according to the present invention preferably contains a varnish and a pigment for the active energy ray-curable flat plate ink according to the present invention. The active energy ray-curable lithographic ink has high viscosity and excellent fluidity. In addition, since the active energy ray-curable lithographic ink has a high viscosity, it has excellent ground stain resistance. Furthermore, printed matter using active energy ray-curable lithographic ink shows high gloss.

The active energy ray-curable flat plate ink according to the present invention preferably contains 35 parts by mass or more and 90 parts by mass or less of the varnish for active energy ray-curable flat plate ink when the total amount of the ink is 100 parts by mass. Since the active energy ray-curable lithographic ink has excellent pigment dispersibility and good ground stain resistance during printing, the content is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, and 50 parts by mass or more. More preferred. Since the fluidity of the active energy ray-curable lithographic ink can be obtained, the content is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and further preferably 70 parts by mass or less.

As the pigment, at least one selected from inorganic pigments and organic pigments generally used in lithographic inks can be used.

Specific examples of the inorganic pigment used in the present invention include titanium dioxide, calcium carbonate, barium sulfate, red iron oxide, cadmium red, chrome yellow, zinc yellow, dark blue, ultramarine blue, organic bentonite, alumina white, iron oxide, carbon black, graphite, and the like. Examples include aluminum.

Examples of organic pigments include phthalocyanine pigments, soluble azo pigments, insoluble azo pigments, azolake pigments, quinacridone pigments, isoindolin pigments, slen pigments, metal complex pigments, and the like. Specific examples thereof include phthalocyanine. Examples thereof include blue, phthalocyanine green, azo red, mono azo red, mono azo yellow, disazo red, disazo yellow, quinacridone red, quinacridone magenta, and isoindrin yellow.

These pigments can be used alone or in combination of two or more.

The pigment concentration contained in the active energy ray-curable flat plate ink according to the present invention is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, in order to obtain the printing paper surface density when the total amount of the ink is 100 parts by mass. It is preferable, and more preferably 15 parts by mass or more. Further, since the active energy ray-curable lithographic ink has good fluidity, the content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 25 parts by mass or less.

The active energy ray-curable lithographic ink according to the present invention preferably contains a photopolymerization initiator in order to improve the sensitivity. In addition, a sensitizer may be included to assist the effect of the photopolymerization initiator. There are mechanically different types of such photopolymerization initiators, such as a single molecule direct cleavage type, an ion pair electron transfer type, a hydrogen abstraction type, and a two molecule complex system, and they can be selected and used.

The photopolymerization initiator used in the present invention is preferably one that generates an active radical species, and specific examples thereof include 4,4-bis (dimethylamino) benzophenone (also known as Michler ketone), α-hydroxyacetophenone, and α. -Aminoacetophenone, acylphosphine oxide, titanocene, o-acyloximes 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propan-1-one, 2-benzyl-2-dimethylamino- Examples thereof include 1- (4-morpholinophenyl) -butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenyl-phosphine oxide and the like. Specific examples of the sensitizer include 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 4,4-bis (diethylamino) -benzophenone, 4,4-bis (dimethylamino) chalcone, and p-dimethylaminocinna. Examples thereof include millidenindanone, 1,3-bis (4-dimethylaminobenzal) acetone, N-phenyl-N-ethylethanolamine, ethyl diethylaminobenzoate, 3-phenyl-5-benzoylthiotetrazole and the like.

In the present invention, one or more photopolymerization initiators and sensitizers can be used.

The content of the photopolymerization initiator is preferably 0.1 part by mass or more, preferably 1 part by mass or more, because the active energy ray-curable flat plate ink can obtain good sensitivity when the total amount of the ink is 100 parts by mass. Is more preferable, and 3 parts by mass or more is further preferable. Since the storage stability of the active energy ray-curable lithographic ink is improved, the content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less. When a sensitizer is added, the content thereof is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, because the active energy ray-curable flat plate ink can obtain good sensitivity. More than parts by mass is more preferable. Since the storage stability of the active energy ray-curable lithographic ink is improved, the content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less.

The active energy ray-curable lithographic ink according to the present invention preferably contains a pigment dispersant. Although the optimum content varies depending on the density, particle size, surface area, etc. of the pigment used, the pigment dispersant acts on the surface of the pigment and suppresses the aggregation of the pigment. By improving the pigment dispersibility of the active energy ray-curable flat plate ink, the fluidity of the active energy ray-curable flat plate ink is improved.

The content of the pigment dispersant is preferably 5 parts by mass or more and 50 parts by mass or less because the fluidity of the active energy ray-curable flat plate ink is improved with respect to 100 parts by mass of the pigment.

The active energy ray-curable lithographic ink according to the present invention can use additives such as wax, antifoaming agent, and transferability improver, if necessary.

A method for producing an active energy ray-curable lithographic ink according to the present invention will be described. The active energy ray-curable flat plate ink according to the present invention is a varnish for active energy ray-curable flat plate ink according to the present invention, together with pigments, additives, and other components, as well as a kneader, a three-roll mill, a ball mill, a planetary ball mill, and a bead mill. It is obtained by uniformly mixing and dispersing with a stirrer / kneader such as a roll mill, an attritor, a sand mill, a gate mixer, a paint shaker, a homogenizer, and a self-revolving stirrer. Defoaming under vacuum or reduced pressure conditions is also preferably performed after mixing and dispersing, or in the process of mixing and dispersing.

The method for producing a printed matter using the active energy ray-curable lithographic ink according to the present invention is as follows. First, the active energy ray-curable lithographic ink according to the present invention is applied onto a base material to be printed. Then, the ink on the substrate is cured by irradiating with active energy rays to obtain a printed matter having an ink curing film. Examples of the base material include, but are not limited to, art paper, coated paper, cast paper, synthetic paper, newspaper paper, aluminum vapor-deposited paper, metal, polypropylene, polyethylene terephthalate, and the like.

As a method of applying the active energy ray-curable slab ink according to the present invention on the substrate, (step 1) the step of applying the active energy ray-curable slab ink to the blanket, and (step 2) the said It is preferable to include a step of transferring the active energy ray-curable flat plate ink. Specific examples of the coating method on the substrate include well-known methods such as flexographic printing, offset printing, gravure printing, screen printing, and bar coater. Of these, the lithographic printing method is preferable. There are two methods for lithographic printing, one with water and the other without water, but either method can be used. The thickness of the ink curing film applied on the substrate is preferably 0.1 to 50 μm.

(Step 3) After the above (step 2), the ink on the substrate is irradiated with active energy rays to cure it. As the active energy ray, any one having the excitation energy required for the curing reaction can be used, but for example, ultraviolet rays and electron beams are preferably used. When curing with an electron beam, an electron beam device having an energy ray of 100 to 500 eV is preferably used. When curing by ultraviolet rays, an ultraviolet irradiation device such as a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, or an LED is preferably used. For example, when a metal halide lamp is used, it is conveyed by a conveyor by a lamp having an illuminance of 80 to 150 W / cm. Curing at a speed of 50 to 150 m / min is preferable from the viewpoint of productivity.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited thereto.

(1) Resin production In a reaction vessel equipped with a stirrer, a reflux cooling tube, a thermometer and a nitrogen gas introduction tube, 150 parts by mass of propylene glycol monomethyl ether acetate (hereinafter, PGMIA) and 55 parts by mass of styrene (ST) were used as solvents. 15 parts by mass of ethyl acrylate (EA) and 30 parts by mass of acrylic acid (AA) were charged, and 4 parts by mass of 2,2'-azobis (2-methylbutyronitrile) (hereinafter, ABN-E) was added as a polymerization initiator. Then, a dropping polymerization reaction was carried out at 140 ° C. for 1.5 hours with reflux and stirring, and the mixture was kept warm for 1 hour. Then, the temperature was raised to 160 ° C., the solvent was distilled off while continuing stirring at normal pressure, then the pressure was reduced to 50 mHg or less at the same temperature, the solvent was completely distilled off, and the weight average molecular weight (hereinafter, Mw) was 25. A resin 1 having an acid value of 000 and an acid value of 160 mgKOH / g was obtained. The results are shown in Table 1. The weight average molecular weight of the resin is a value measured by GPC. GPC is HLC-8220 (manufactured by Tosoh Co., Ltd.), columns are TSKgel SuperHM-H (manufactured by Tosoh Co., Ltd.), TSKgel SuperHM-H (manufactured by Tosoh Co., Ltd.), TSKgel SuperH2000 (manufactured by Tosoh Co., Ltd.) in that order. The one linked with the above was used, tetrahydrofuran was used as a mobile phase, and RI detection was measured using the RI detector built in the GPC. A calibration curve was prepared using a polystyrene standard material, and the weight average molecular weight of the resin was calculated. The measurement sample is diluted with tetrahydrofuran so that the resin concentration becomes 0.25% by mass, and the diluted solution is dissolved by stirring with a mix rotor (MIX-ROTAR VMR-5, manufactured by AS ONE Co., Ltd.) at 100 rpm for 5 minutes. The mixture was obtained by filtering with a 0.2 μm filter (Z227536-100EA, manufactured by SIGMA). The measurement conditions were a driving amount of 10 μL, an analysis time of 30 minutes, a flow rate of 0.4 mL / min, and a column temperature of 40 ° C.

Explanation of abbreviations in Table 1
PGMIA: Propylene Glycol Monomethyl Ether Acetate ST: Styrene EA: Ethyl Acrylate AA: ABN-E Acrylic Acid; 2,2'-azobis (2-methylbutyronitrile).

Resins 2 to 4 were obtained in the same manner as in Resin 1, except that the resin composition and polymerization conditions were changed as shown in Table 1. Table 1 shows the resin composition and resin properties.

(2) Manufacture of varnish <Manufacture of varnishes 1 to 5>
Resin 1 is 30 parts by mass, (2) Trimethylol propantriacrylate ethylene oxide adduct "Miramer" (registered trademark) M3130 (manufactured by MIWON) is 69.995 parts by mass as a compound having an ethylenically unsaturated group, (3). 0.005 parts by mass of Jeffamine D230 (manufactured by Tomoe Kogyo Co., Ltd., bifunctional amine compound) as a compound, 0.1 parts by mass of 4-methoxyphenol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a polymerization inhibitor, container After stirring and dissolving at 100 ° C. for 5 hours, the mixture was cooled to room temperature to obtain an active energy ray-curable flat plate ink varnish 1.

Varnishes 2 to 5 are obtained in the same manner as varnish 1 except that resin 1 is changed to resin 2 and (2) a compound having an ethylenically unsaturated group and (3) a compound are changed as shown in Table 2. It was.

<Manufacturing of varnishes 6-9>
30 parts by mass of resin 2, (2) 69.99 parts by mass of pentaerythritol tetraacrylate ethylene oxide adduct PET5EO4A (manufactured by DBC) as a compound having an ethylenically unsaturated group, (3) 4-hydroxy-2 as a compound, 0.01 parts by mass of 2,6,6-tetramethylpiperidin-1-oxyl (N-oxyl compound manufactured by Sigma Aldrich) was weighed into a container and dissolved by stirring at 100 ° C. for 5 hours. After that, the varnish 6 for active energy ray-curable flat plate ink was obtained by cooling to room temperature.

(3) Varnishes 7 to 9 were obtained in the same manner as in varnish 6 except that the compounds were changed as shown in Table 2.

<Manufacturing of varnishes 10 to 12>
30 parts by mass of resin 3, (2) 70.0 parts by mass of trimethylolpropane triacrylate ethylene oxide adduct "Miramer" (registered trademark) M3130 (manufactured by MIWON) as a compound having an ethylenically unsaturated group, a polymerization inhibitor As a result, 0.1 part by mass of 4-methoxyphenol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was weighed into a container, stirred and dissolved at 100 ° C. for 5 hours, and then cooled to room temperature to obtain active energy rays. A varnish 10 for curable flat plate ink was obtained.

Varnishes 11 and 12 were obtained in the same manner as in varnish 10, except that the amounts of the resin, (2) the compound having an ethylenically unsaturated group, and the polymerization inhibitor were changed as shown in Table 2.

(3) Ink manufacturing <Ink raw material>
Varnish: Varnish 1-12
Pigment: Carbon black, "MOGUL" (registered trademark) E (manufactured by CABOT)
Photopolymerization Initiator: "Irgacure" (registered trademark) 907 (manufactured by BASF)
"Irgacure" (registered trademark) TPO-L (manufactured by BASF)
Sensitizer: Diethylaminobenzophenone (manufactured by Tokyo Kasei Co., Ltd.)
Compounds with ethylenically unsaturated groups and diluting monomers: Trimethylol propantriacrylate ethylene oxide adduct "Miramer" (registered trademark) M3130 (manufactured by MIWON), pentaerythritol tetraacrylate ethylene oxide adduct "Miramer" (registered trademark) M4004 (MIWON), Pentaerythritol tetraacrylate ethylene oxide adduct PET5EO4A (DBC), Pentaerythritol tetraacrylate ethylene oxide adduct ATM-35E (Shin-Nakamura Chemical Industry Co., Ltd.)
Constituent pigment: "Micro Ace" (registered trademark) P-3 (manufactured by Nippon Talc Co., Ltd.)
Pigment dispersant: "Disparon" (registered trademark) DA-325 (manufactured by Kusumoto Kasei Co., Ltd.)
Wax: PTFE, KTL-4N (manufactured by Kitamura Co., Ltd.).

<Measurement method of ethylene oxide chain in varnish>
LC / MS measurements were performed on varnishes 1-12 to obtain mass spectra and product spectra. LC / MS measurement was performed by LC system: Ultimate 3000 (manufactured by Thermo Fisher Scientific), MS system: Orbitrap Fusion (manufactured by Thermo Fisher Scientific), column: Cadenza CD-C18 2.0 × 150 mm, 3 μm. Mobile phase: 10 mmol / L ammonium acetate aqueous solution and acetonitrile / tetrahydrofuran = 7/3, flow rate: 0.3 mL / min, column temperature: 45 ° C., injection volume: 3 μL, ionization: ESI method, MS detection: full scan (m /) z200-3000) ・ Positive ion detection. The structure of the compound having an ethylenically unsaturated group was identified from the obtained mass spectrum and product spectrum, and the number of ethylene oxide chains in one molecule was determined.

<Ink manufacturing>
50 parts by mass of varnish shown in Table 3, pigment: "MOGUL" (registered trademark) 19 parts by mass, photopolymerization initiator: "Irgacure" (registered trademark) 907 by 4 parts by mass, "Irgacure" (registered trademark) 6 parts by mass of TPO-L, 5 parts by mass of sensitizer: diethylaminobenzophenone, 11 parts by mass of diluted monomer shown in Table 3, extender pigment: 2 parts by mass of "Microace" (registered trademark) P-3, pigment Dispersant: 2 parts by mass of "Disparon" (registered trademark) DA-325, wax: 1 part by mass of PTFE and KTL-4N (manufactured by Kitamura Co., Ltd.), and three roll mill "EXAKT" (registered trademark) Using M-80S (manufactured by EXAKT), the roller gap scale was set to 1, the roll rotation speed scale was set to 500 rpm, and kneading was performed four times to obtain an active energy ray-curable flat plate ink. Here, as the diluting monomer, the same compound as (2) the compound having an ethylenically unsaturated group used for the varnish was used.

<Measurement method of ethylene oxide chain in ink>
Dichloromethane is added to extract the organic components in the ink, and the extract is ultracentrifuged at 100,000 rpm for 10 minutes using an ultracentrifuge Optima XE-100 (manufactured by BECKMAN COULTER). And separated into insoluble matter. Dichloromethane-soluble matter was cast at 60 ° C., and LC / MS measurement was performed on the organic components in the ink from which dichloromethane was removed to obtain a mass spectrum and a product spectrum. LC / MS measurement was performed by LC system: Ultimate 3000 (manufactured by Thermo Fisher Scientific), MS system: Orbitrap Fusion (manufactured by Thermo Fisher Scientific), column: Cadenza CD-C18 2.0 × 150 mm, 3 μm. Mobile phase: 10 mmol / L ammonium acetate aqueous solution and acetonitrile / tetrahydrofuran = 7/3, flow rate: 0.3 mL / min, column temperature: 45 ° C., injection volume: 3 μL, ionization: ESI method, MS detection: full scan (m /) z200-3000) ・ Positive ion detection. The structure of the compound having an ethylenically unsaturated group was identified from the obtained mass spectrum and product spectrum, and the number of ethylene oxide chains in one molecule was determined.

(4) Waterless printing test A waterless lithographic printing plate (TAC-VG5, manufactured by Toray Co., Ltd.) was mounted on an offset printing machine (Oliver 266EPZ, manufactured by Sakurai Graphic System Co., Ltd.), and each ink manufactured was used. Print on 5000 sheets of coated paper, and use an ultraviolet irradiation device (120 W / cm, 1 ultra-high pressure metahara lamp) manufactured by USHIO Co., Ltd. to irradiate ultraviolet rays at a belt conveyor speed of 80 m / min to cure the ink. I got a print.

(5) Evaluation method for varnish and ink
(5-1) Storage stability of varnish The storage stability of varnish was evaluated by the time until (1) white turbidity due to aggregation and precipitation of the resin was observed when stored in a vacuum oven. Weigh 40 g of varnish into a 50 cc screw tube and store it in a vacuum oven "DP22" (manufactured by Yamato Scientific Co., Ltd.) in an open system without a lid under vacuum (0.05 atm) and acceleration conditions at 60 ° C. The time until white turbidity was observed by visually observing the appearance every 10 hours was defined as the stable time. If the stabilization time is 50 hours or more, there is no practical problem, 100 hours or more is more preferable, and 200 hours or more is further preferable.

(5-2) Storage Stability of Ink The storage stability of ink was evaluated by increasing viscosity (increased viscosity) when stored in an oven at 60 ° C. under atmospheric pressure for 3 months. [Viscosity after storage]-[Initial viscosity before storage] is defined as increased viscosity, and the lower the increased viscosity, the better the storage stability. The increased viscosity is preferably 50 Pa · s or less, more preferably 35 Pa · s or less, and even more preferably 20 Pa · s or less.

The viscosity of the ink was determined by using a rheometer MCR301 (manufactured by Anton Pearl) equipped with a cone plate (cone angle 1 °, φ = 40 mm), ink amount: 0.15 mL, temperature: 25 ° C., rotation speed: 0. It was measured under the condition of 5 rpm.

(5-3) Ground stain resistance (measurement of ground stain start temperature)
In the waterless printing test of (4) above, the plate surface temperature of the printing plate during printing is sequentially measured, and the temperature at which ground stain is recognized in the non-image area of the printed matter is used as the ground stain start temperature to determine the ground stain resistance. It was used as an index. If the ground pollution start temperature is 30 ° C. or higher, there is no practical problem, and 32 ° C. or higher is preferable.

(5-4) Misting resistance Ink 1.3 mL is developed on an incometer (manufactured by Tester Sangyo Co., Ltd.), rotated at a roll temperature of 38 ° C. and 400 rpm for 1 minute, and the ink is placed on white paper directly under the roll. The average value of the scattering degree was arbitrarily measured at 5 points using a Gretag color difference meter (SpectroEye manufactured by Gretag Macbeth), and the blank value (measured value of white paper measured in advance by the same method) was subtracted. Was evaluated by asking for. When the reflection density exceeded 0.05, the misting resistance was poor and evaluated as x, and when it was 0.05 or less, the misting resistance was good and evaluated as ◯.

[Examples 1 and 2]
When the varnish was evaluated according to 5-1 above, as shown in Table 2, there was no practical problem in storage stability. Further, when the ink obtained by using the varnish was evaluated according to the above 5-2, 5-3, 5-4, as shown in Table 3, the increased viscosity had no problem in practical use, and the ground stain start temperature was changed. In Example 1, there was no problem in practical use, and Example 2 was good. In addition, the misting resistance was also good.

[Examples 3 to 5]
When the varnish was evaluated according to 5-1 above, the storage stability was good as shown in Table 2. Moreover, when the ink obtained by using the varnish was evaluated according to the above 5-2, 5-3, 5-4, as shown in Table 3, the increased viscosity, the ground stain start temperature, and the misting resistance were good. It was a good result.

[Examples 6 to 9]
When the varnish was evaluated according to 5-1 above, the storage stability was very good as shown in Table 2. Moreover, when the ink obtained by using the varnish was evaluated according to the above 5-2, 5-3, 5-4, as shown in Table 3, the increased viscosity was very good, and the ground stain start temperature was determined. Good results were also obtained with regard to misting resistance.

[Comparative Example 1]
When the varnish was evaluated according to 5-1 above, as shown in Table 2, the storage stability was low and it was not practical. Moreover, when the ink obtained by using the varnish was evaluated according to the above 5-2, 5-3, 5-4, as shown in Table 3, the increased viscosity was large and it was not practical. Although the misting resistance was good, the ground pollution start temperature was not practical.

[Comparative Example 2]
When the varnish was evaluated according to 5-1 above, as shown in Table 2, the storage stability was low and it was not practical. Moreover, when the ink obtained by using the varnish was evaluated according to the above 5-2, 5-3, 5-4, as shown in Table 3, the increased viscosity was large and it was not practical. The ground pollution start temperature was good, but the misting resistance was not practical.

[Comparative Example 3]
When the varnish was evaluated according to 5-1 above, as shown in Table 2, the storage stability was low and it was not practical. Moreover, when the ink obtained by using the varnish was evaluated according to the above 5-2, 5-3, 5-4, as shown in Table 3, the increased viscosity was large and it was not practical. The ground pollution start temperature and misting resistance were good.

Claims (10)

It is a copolymer of (1) (a) styrenes, (b) (meth) acrylic acid alkyl ester and (c) a monomer containing a hydrophilic group-containing vinyl monomer, and has an acid value of 150 mgKOH / g or more and 250 mgKOH /. Active energy ray-curable flat plate ink containing a resin containing g or less, (2) a compound having an ethylenically unsaturated group, and (3) one or more compounds selected from a nitroso compound and a polyfunctional amine compound. .. (2) The active energy ray-curable flat plate ink according to claim 1, wherein the compound having an ethylenically unsaturated group is a pentaerythritol tetra (meth) acrylate ethylene oxide adduct. The active energy ray-curable flat plate ink according to claim 2, wherein the number of ethylene oxide chains of the pentaerythritol tetra (meth) acrylate ethylene oxide adduct is 4 or more and 35 or less in one molecule. (1) The active energy ray-curable lithographic ink according to any one of claims 1 to 3, wherein the resin has a weight average molecular weight of 17,000 or more and 30,000 or less. (3) Claims 1 to 4 in which the content of any one or more compounds selected from the nitroso compound and the polyfunctional amine compound is 0.005 part by mass or more and 0.2 part by mass or less in 100 parts by mass of the ink. The active energy ray-curable flat plate ink according to any one of. (3) The present invention according to any one of claims 1 to 5, wherein any one or more compounds selected from the nitroso compound and the polyfunctional amine compound are nitroso compounds, and the nitroso compound is an N-oxyl compound. Active energy ray-curable flat plate ink. The active energy ray-curable lithographic ink according to claim 6, wherein the N-oxyl compound is 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. (3) Any of claims 1 to 5, wherein any one or more compounds selected from the nitroso compound and the polyfunctional amine compound are nitroso compounds, and the nitroso compound is aluminum N-nitrosophenylhydroxylamine. Active energy ray-curable flat plate ink described in Crab. (Step 1) A step of applying the active energy ray-curable lithographic ink according to any one of claims 1 to 8 to a blanket.
(Step 2) A step of transferring the active energy ray-curable lithographic ink onto a substrate,
(Step 3) After the (Step 2), the step of irradiating the ink with active energy rays to cure the ink.
A method for manufacturing printed matter including. It is a copolymer of (1) (a) styrenes, (b) (meth) acrylic acid alkyl ester and (c) a monomer containing a hydrophilic group-containing vinyl monomer, and has an acid value of 150 mgKOH / g or more and 250 mgKOH /. A varnish for active energy ray-curable flat plate ink containing any one or more compounds selected from a resin having an amount of g or less, (2) a compound having an ethylenically unsaturated group, (3) a nitroso compound and a polyfunctional amine compound. ..