Active energy ray-curable lithographic ink and method for producing printed matter using the same

Abstract

To provide an active energy ray-curable lithographic ink with reduced elution of unreacted components after curing.SOLUTION: An active energy ray-curable lithographic ink comprises (a) a resin, (b) a compound having an ethylenically unsaturated group, and (c) a pigment. The active energy ray-curable lithographic ink has a ratio Da / Db of 0.9 or less, where Da is the diffusion coefficient of (b) the compound having an ethylenically unsaturated group to (a) the resin, and Db is the diffusion coefficient of the (b) compound having an ethylenically unsaturated group to polypropylene.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an active energy ray-curable lithographic printing ink and a method for manufacturing a printed matter using the same.

Background Art

[0002] Lithographic printing is a printing method that has been widely spread as a system for supplying printed matters at high speed, in large quantities, and at low cost. In recent years, the use of active energy ray-curable lithographic printing inks that instantaneously cure by irradiating active energy rays such as mercury lamps, metal halide lamps, light-emitting diodes, and electron beams has spread in many fields due to equipment aspects, safety aspects, environmental aspects, and high productivity.

[0003] In recent years, there has been a start of consideration to apply lithographic printing to soft packaging printing used for daily necessities, food products, pharmaceuticals, etc. using a thin plastic film as a base material. Since active energy ray-curable lithographic printing inks can be cured at room temperature in a short time, they are considered to be suitable materials for soft packaging printing using a plastic film with poor heat resistance as a base material.

[0004] As active energy ray-curable lithographic inks, for example, a copolymer of monomers containing styrenes, (meth)acrylic acid alkyl esters, and hydrophilic group-containing vinyl monomers and a varnish containing an ethylenically unsaturated compound, and an active energy ray-curable lithographic ink containing a pigment (see, for example, Patent Document 1), or an ethylene oxide-modified trimethylolpropane tri(meth)acrylate having an average addition mole number of ethylene oxide of 4 to 9 moles per molecule, and a varnish that is a polyester resin having polyethylene terephthalate resin, rosin, and a polyol compound as essential reaction raw materials, an active energy ray-curable ink for lithographic offset printing (see, for example, Patent Document 2), etc. have been proposed.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-143136 [Patent Document 2] Japanese Patent Application Laid-Open No. 2021-195502 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] When applying these inks to the above-mentioned flexible packaging printing, there has been a problem that unreacted monomers and oligomers remaining in the cured ink are likely to elute. The eluted components may contaminate the contents in flexible packaging printing for food applications, etc., or adhere to surrounding objects and people during handling. Therefore, it is required to suppress the elution of unreacted components from the cured ink.

[0007] Therefore, in view of the above problems of the prior art, an object of the present invention is to provide an active energy ray-curable offset printing ink in which the elution of unreacted components after curing is suppressed. [Means for Solving the Problems]

[0008] <1> An active energy ray-curable offset printing ink containing (a) a resin, (b) a compound having an ethylenically unsaturated group, and (c) a pigment, wherein the ratio (Da / Db) of the diffusion coefficient Da of the compound having an ethylenically unsaturated group with respect to (a) the resin to the diffusion coefficient Db of the compound having an ethylenically unsaturated group with respect to polypropylene is 0.9 or less. <2> The active energy ray-curable offset printing ink according to <1>, wherein the density G1 of the (a) resin is 1.11 to 1.30 g / cm 3 The active energy ray-curable offset printing ink according to <1>. <3> The active energy ray-curable offset printing ink according to <1> or <2>, which contains a copolymer containing (a-1) an alkyl (meth)acrylate and (a-2) styrene as copolymerization components as the (a) resin. <4>The ratio ((a-2) / (a-1)) of the content (mol%) of (a-2) styrene to the content (mol%) of (a-1) alkyl (meth)acrylate in the copolymer component is 0.20 to 1.10, the active energy ray-curable offset printing ink according to <3>. <5>The active energy ray-curable offset printing ink according to <3> or <4>, wherein the alkyl group in the (a-1) alkyl (meth)acrylate has 1 to 6 carbon atoms. <6>The active energy ray-curable offset printing ink according to any one of <1> to <5>, wherein the (a) resin has a hydrophilic functional group. <7>The ratio (G2 / G1) of the density G2 of the compound having an ethylenically unsaturated group (b) to the density G1 of the (a) resin is 1.03 or less, the active energy ray-curable offset printing ink according to any one of <1> to <6>. <8>The active energy ray-curable offset printing ink according to any one of <1> to <7>, wherein the compound having an ethylenically unsaturated group (b) has 3 to 6 ethylenically unsaturated groups. <9>The ratio ((a) / (b)) of the weight average molecular weight (Mw) of the (a) resin to the molecular weight of the compound having an ethylenically unsaturated group (b) is 10 to 80, the active energy ray-curable offset printing ink according to any one of <1> to <8>. <10>The active energy ray-curable offset printing ink according to any one of <1> to <9>, wherein the acid value of the (a) resin is 100 to 250 g / KOHmg. <11>A method for producing a printed matter, comprising a step of transferring the active energy ray-curable offset printing ink according to any one of <1> to <10> onto a substrate, and a step of irradiating the transferred active energy ray-curable offset printing ink with active energy rays. <12>The method for producing a printed matter according to <11>, wherein a plastic film, a plastic film laminated paper, and / or a metal vapor-deposited plastic film is used as the substrate. <13>The method for producing a printed matter according to <11> or <12>, wherein the active energy ray is an electron beam or ultraviolet ray.

Advantages of the Invention

[0009] According to the active energy ray-curable offset printing ink of the present invention, elution of unreacted components after curing can be suppressed.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be specifically described.

[0011] The active energy ray-curable offset printing ink according to the present invention (hereinafter, may be abbreviated as "ink") contains (a) a resin, (b) a compound having an ethylenically unsaturated group (hereinafter, may be abbreviated as "(b) compound"), and (c) a pigment. By containing (a) the resin, fluidity suitable for the ink can be imparted. By containing (b) the compound, the property of curing by active energy rays can be imparted. By containing (c) the pigment, a specific color can be imparted to the ink. In the following description, the state before curing containing these components is described as "ink", and the state cured by active energy rays is described as "ink cured film".

[0012] As described above, in the case of soft package printing such as plastic film, conventionally known inks have had the problem that unreacted components remaining in the ink cured film are likely to elute. The present inventors considered suppressing elution by reducing the mobility of unreacted components even when unreacted components remain in the ink cured film, and focused on the diffusion coefficient as an index of the mobility of unreacted components. The diffusion coefficient is an index representing the degree of diffusion of a substance per unit time in a specific medium, and the larger the diffusion coefficient, the easier it is for the substance to diffuse in the medium. In the present invention, the diffusion coefficient Da of the (b) compound with respect to the (a) resin is used as an index of the mobility of the unreacted component in the ink cured film, and the diffusion coefficient Db of the (b) compound with respect to polypropylene, which is a general resin, is used as an index of the mobility of the unreacted component outside the ink cured film, and attention is paid to the ratio (Da / Db) of these. The larger Da is with respect to the reference Db, the easier it is for the unreacted (b) compound remaining in the ink cured film to diffuse into the (a) resin, and the easier it is to elute from the ink cured film. On the other hand, the smaller Da is with respect to the reference Db, the more difficult it is for the unreacted (b) compound in the ink cured film to be confined in the (a) resin and diffuse, and the more difficult it is to elute from the ink cured film. As described above, the unreacted components eluted from the ink cured film may contaminate the contents in soft package printing for food product applications, etc., or adhere to surrounding objects or people during handling. Therefore, in the present invention, elution of unreacted components from the ink cured film is suppressed by setting Da / Db to 0.9 or less. When Da / Db exceeds 0.9, unreacted components are likely to elute from the ink cured film. Da / Db is preferably 0.85 or less, more preferably 0.8 or less.

[0013] As a method for making Da / Db 0.9 or less, for example, a method of combining the (a) resin and the (b) compound of the preferred embodiment described later, more specifically, a combination of a resin having a large density G1 and a (b) compound having a large molecular weight, or setting the density ratio (G2 / G1) and the molecular weight ratio ((a) / (b)) within the preferred ranges described later, etc. can be mentioned.

[0014] The diffusion coefficient can be calculated using a commercially available molecular dynamics calculation program based on (a) the resin and (b) the structure and molecular weight of the compound. Specifically, it can be calculated from the mean square displacement using the Forcite molecular dynamics calculation program of Materials Studio (manufactured by Accelrys, Inc.) with the NVT ensemble. Here, the weight average molecular weight of polypropylene is assumed to be the same as that of (a) the resin. When (a) the resin and (b) the compound are known, their structures and molecular weights are input into Forcite. On the other hand, the structures and molecular weights of (a) the resin and (b) the compound can be specified by the following method.

[0015] First, dissolve the ink in a suitable solvent, filter to extract the soluble portion, perform centrifugation, and fractionate (a) the resin and (b) the compound by high-performance liquid chromatography (HPLC) as needed. The molecular weights of (a) the resin and (b) the compound can be measured by subjecting them to gel permeation chromatography (GPC) or a mass spectrometer, respectively. More specifically, after dissolving (a) the resin in a developing solvent (tetrahydrofuran), subject it to a GPC equipped with a column (e.g., "SHODEX" (registered trademark) GPC KF-801, manufactured by Resonac Co., Ltd.), and use the weight-average molecular weight of polystyrene determined as a standard sample as the molecular weight of (a) the resin. Also, after dissolving (b) the compound in a developing solvent (tetrahydrofuran), subject it to a mass spectrometer to measure the mass-to-charge ratio, calculate the mass of (b) the compound, and then subtract the mass of the ion used in the mass spectrometry to obtain the molecular weight of (b) the compound. The structures of (a) the resin and (b) the compound can be identified by a nuclear magnetic resonance apparatus (NMR). When the ink of the present invention contains two or more kinds of (a) resins, let the diffusion coefficient of (b) the compound with respect to the resin having the highest content be Da. However, when there are two or more kinds of resins having the highest content, select the resin having the largest Da among those resins. Also, when (b) the compound contains two or more kinds, select the (b) compound having the largest Db, and let the diffusion coefficient of that compound with respect to (a) the resin be Da and the diffusion coefficient with respect to polypropylene be Db. However, in the selection of (b) the compound, trace components having a content of 4% by mass or less in the ink shall be excluded.

[0016] Examples of (a) the resin include acrylic resins, styrene-acrylic resins, styrene-maleic resins, rosin-modified maleic resins, rosin-modified acrylic resins, epoxy resins, polyester resins, polyurethane resins, butyral resins, polyamide resins, urea resins, phenol resins, and the like. Two or more of these may be contained.

[0017] Among these, styrene acrylic resin is preferred, and a copolymer containing (a-1) alkyl (meth)acrylate and (a-2) styrene as copolymerization components is more preferred. Here, "(meth)acrylic acid" is a general term for acrylic acid and methacrylic acid. Using (a-1) alkyl (meth)acrylate as a copolymerization component, that is, when the (a) resin has the residue of (a-1), the compatibility between the (a) resin and the (b) compound is improved, the ink viscosity at low shear can be lowered, and the ink transferability is improved. Furthermore, the density of the (a) resin is increased, and the entanglement of the (a) resin in the ink becomes denser, so the diffusibility of the (b) compound with respect to the (a) resin is suppressed, and Da can be reduced. For this reason, the elution of unreacted components from the ink cured film can be more suppressed. On the other hand, using (a-2) styrene as a copolymerization component, that is, when the (a) resin has the residue of (a-2), the ink viscosity at high shear can be increased, and the phenomenon of ink sticking to the non-image area (ground contamination) can be suppressed. When two or more kinds of (a) resins are contained, it is preferable that the resin with the highest content is a copolymer containing (a-1) alkyl (meth)acrylate and (a-2) styrene as copolymerization components.

[0018] Examples of the (a-1) alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, etc. Two or more of these may be used. The number of carbon atoms of the alkyl group is preferably 1 to 6, and the volume of the (a) resin can be appropriately suppressed to increase the density. As a result, the diffusibility of the (b) compound with respect to the (a) resin in the ink is suppressed, and Da can be reduced. For this reason, the elution of unreacted components from the ink cured film can be more suppressed. The alkyl group may be either linear or branched, and a linear shape is preferred.

[0019] Examples of the styrene include styrene and α-methylstyrene. Two of these may be used. Among these, styrene is preferred from the viewpoint of stability against active energy.

[0020] The ratio ((a-2) / (a-1)) of the content (mol%) of (a-2) styrene to the content (mol%) of (a-1) alkyl (meth)acrylate in the copolymer component is preferably from 0.20 to 1.10. By setting (a-2) / (a-1) to 0.20 or more, the ink viscosity at high shear can be increased to further suppress ground contamination. More preferably, (a-2) / (a-1) is 0.25 or more. On the other hand, by setting (a-2) / (a-1) to 1.10 or less, the compatibility between the (a) resin and the (b) compound having an ethylenically unsaturated group can be further improved, the ink viscosity at low shear can be decreased to further improve the ink transferability, the density of the (a) resin can be further increased, the entanglement of the (a) resin in the ink can be made denser, the diffusibility of the (b) compound with respect to the (a) resin can be further suppressed, and Da can be made smaller. For this reason, elution of unreacted components from the ink cured film can be further suppressed. More preferably, (a-2) / (a-1) is 1.00 or less, and even more preferably 0.80 or less. Here, when the copolymer component contains two or more kinds of (a-1) alkyl (meth)acrylate and / or (a-2) styrene, (a-2) / (a-1) is the ratio as a whole of the total of the two or more kinds.

[0021] The (a) resin preferably has a hydrophilic functional group. By having a hydrophilic functional group, the dispersibility of the (c) pigment contained in the ink can be improved, and ground contamination can be suppressed. Examples of the hydrophilic functional group include a carboxyl group, a hydroxyl group, an amino group, a phosphoric acid group, a sulfonyl group, a mercapto group, and an amide group. Two or more of these may be had. Among these, a carboxyl group and a hydroxyl group are preferred from the viewpoint of ease of functional group introduction.

[0022] (a) The acid value of the resin is preferably 100 to 250 mgKOH / g. By setting the acid value to 100 mgKOH / g or more, the dispersibility of the (c) pigment contained in the ink can be improved, and ground contamination can be suppressed. Also, since the polarity of the (a) resin increases and the interaction with the (b) compound becomes stronger, the diffusibility of the (b) compound with respect to the (a) resin in the ink is suppressed, and Da can be made smaller. For this reason, elution of unreacted components from the ink cured film can be further suppressed. On the other hand, by setting the acid value of the (a) resin to 250 mgKOH / g or less, the compatibility with the (b) compound is improved, and the ink viscosity at low shear can be made lower to further improve the ink transferability. The acid value of the (a) resin is more preferably 230 mgKOH / g or less.

[0023] (a) The acid value of the resin can be determined in accordance with the neutralization titration method in Section 3.1 of the test method of JIS K 0070:1992. When two or more kinds of (a) resins are contained, the acid value of the whole (a) resin is preferably within the above range.

[0024] (a) The weight average molecular weight of the resin is preferably 5,000 to 100,000. By setting the weight average molecular weight to 5,000 or more, the ink viscosity at high shear can be made higher to further reduce ground contamination. The weight average molecular weight of the (a) resin is more preferably 8,000 or more, and even more preferably 10,000 or more. On the other hand, by setting the weight average molecular weight to 100,000 or less, the ink viscosity at low shear can be made lower to further improve the ink transferability. Also, since the ink viscosity can be made low even when the content of the (a) resin is increased, the content of the (b) compound having an ethylenically unsaturated group can be made low, so that unreacted components in the ink cured film are reduced, and elution of unreacted components from the ink cured film can be further suppressed. The weight average molecular weight of the (a) resin is more preferably 70,000 or less, and even more preferably 50,000 or less.

[0025] (a) The weight-average molecular weight of the resin can be measured by GPC in the same manner as when obtaining the diffusion coefficient described above. When two or more types of (a) resins are contained, it is preferable that the weight-average molecular weight of the (a) resin with the highest content is within the above range. However, when there are two or more resins with the highest content, among these resins, it is preferable that the weight-average molecular weight of the resin with the largest Da is within the above range.

[0026] (a) The density G1 of the resin is preferably 1.11 to 1.30 g / cm 3 . By setting the density to 1.11 g / cm 3 or higher, the entanglement of the (a) resin in the ink becomes denser, and a structure sufficiently dense with respect to the molecular volume of the (b) compound is formed. Therefore, the diffusibility of the (b) compound with respect to the (a) resin is suppressed, and Da can be made smaller. For this reason, elution of unreacted components from the ink cured film can be further suppressed. A density of 1.15 g / cm 3 or higher is more preferable. On the other hand, by setting the density to 1.30 g / cm3 or lower, the crystallinity of the (a) resin can be suppressed, the compatibility with the (b) compound can be further improved, the ink viscosity at low shear can be made lower, and the ink transferability can be further improved.

[0027] (a) The density G1 of the resin can be determined in accordance with Method B (pycnometer method) of Section 5.2 of the test method of JIS K 7112:1999. More specifically, the (a) resin is separated from the ink by the method described above, weighed into a pycnometer, and then a poor solvent is injected up to the volume limit as the immersion liquid, and the weight is measured. Next, all the samples in the pycnometer are taken out, dried, and then the immersion liquid is injected up to the volume limit, and the weight is measured. The density is calculated from the following formula based on the measurement results, and the average value of three measurements is taken as G1. ρ R = [m1 / (m1 + m3 - m2)] × ρ L ρ R : Density of the resin (g / cm 3 ) m1: Weight of the resin placed in the pycnometer (g) m2: Weight (g) of the pycnometer filled with the immersion liquid with the sample m3: Weight (g) of the pycnometer filled only with the immersion liquid ρ L : Density of the immersion liquid (g / cm 3 ).

[0028] (a) When the resin is, for example, an acrylic resin, a styrene-acrylic resin, or a styrene-maleic acid resin, it can be produced, for example, by the following method. That is, a carboxy group-containing monomer such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetate, or an acid anhydride thereof, a hydroxy group-containing monomer such as 2-hydroxyethyl acrylate, an amino group-containing monomer such as dimethylaminoethyl methacrylate, a phosphate group-containing monomer such as 2-(meth)acryloyloxyethyl acid phosphate, a sulfonyl group-containing monomer such as (meth)acrylamide t-butylsulfonic acid, a mercapto group-containing monomer such as 2-(mercaptoacetoxy)ethyl acrylate, an amide group-containing monomer such as (meth)acrylamide, a (meth)acrylate ester, styrene, acrylonitrile, vinyl acetate, etc. are selected from the compounds, and are polymerized or copolymerized using a radical polymerization initiator to obtain the resin.

[0029] (a) When the resin has an ethylenically unsaturated group, it can be produced, for example, by the following method. That is, an ethylenically unsaturated compound having a glycidyl group or an isocyanate group or (meth)acrylic acid chloride, allyl chloride, etc. is subjected to an addition reaction with a mercapto group, an amino group, a hydroxy group, or a carboxy group which is an active hydrogen-containing group in the resin, whereby an ethylenically unsaturated group can be introduced. Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl (meth)acrylate, allyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, etc.

[0030] The ink according to the present invention preferably contains (a) resin in an amount of 10% by mass or more. Due to the entanglement of the molecular chains of (a) resin, the ink viscosity at high shear can be increased, thereby further suppressing ground contamination. On the other hand, the content of (a) resin is preferably 50% by mass or less, and the ink viscosity at low shear can be decreased, thereby further improving the ink transferability. When two or more kinds of (a) resin are contained, the total content of (a) resin is preferably within the above range.

[0031] (b) As the compound, a compound having a (meth)acryloyl group is preferable. For example, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane di(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, polyethylene glycol di(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol propoxylate, glycerin di(meth)acrylate, glycerin tri(meth)acrylate, diglycerin tri(meth)acrylate, diglycerin tetra(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,11-undecanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,13-tridecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,15-pentadecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,17-heptadecanediol di(meth)acrylate, 1,18-octadecanediol di(meth)acrylate, 4-methyl-1,10-decanediol di(meth)acrylate, 4-ethyl-1,10-decanediol di(meth)acrylate, and alkylene oxide adducts thereof can be mentioned. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and tetramethylene oxide. Two or more of these may be contained.

[0032] (b) The compound preferably has 3 to 6 ethylenically unsaturated groups in one molecule. By having 3 or more ethylenically unsaturated groups, the curing reaction by active energy rays proceeds easily, so that unreacted components in the ink cured film can be reduced, and elution of unreacted components from the ink cured film can be more suppressed. On the other hand, by having 6 or less ethylenically unsaturated groups, interference between ethylenically unsaturated groups within the same molecule is suppressed, radical reactivity is enhanced, unreacted components in the ink cured film can be reduced, and elution of unreacted components from the ink cured film can be more suppressed. It is more preferable to have 5 or less ethylenically unsaturated groups.

[0033] Examples of the compound having 3 to 6 ethylenically unsaturated groups include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin tri(meth)acrylate, diglycerin tri(meth)acrylate, diglycerin tetra(meth)acrylate, and alkylene oxide adducts thereof. As the alkylene oxide, (a) from the viewpoints of solubility with the resin and reduction of molecular diffusibility, ethylene oxide and propylene oxide are preferable. Two or more of these may be contained. (b) When two or more compounds are contained, it is preferable that the compound having the largest Db is within the above range. However, in the selection of the (b) compound, trace components having a content of 4% by mass or less in the ink shall be excluded.

[0034] (b) The molecular weight of the compound is preferably 250 or more, which can increase the ink viscosity during high shear and further suppress ground contamination. Also, since the volume of the molecule of (b) the compound becomes sufficiently large relative to the entanglement state of (a) the resin, the diffusibility of (b) the compound with respect to (a) the resin is suppressed, and Da can be made smaller. For this reason, elution of unreacted components from the ink cured film can be further suppressed. On the other hand, the molecular weight of (b) the compound is preferably 1,500 or less, because the curing reaction by active energy rays easily proceeds, so that unreacted components in the ink cured film can be reduced, and elution of unreacted components from the ink cured film can be further suppressed. The "molecular weight" referred to here means relative molecular mass. When (b) the compound has a molecular weight distribution, in the mass spectrometry described later, the relative molecular mass of the compound with the strongest relative intensity of the detection spectrum is defined as the molecular weight of (b) the compound.

[0035] (b) The molecular weight of the compound can be measured by mass spectrometry in the same manner as in the case of obtaining the diffusion coefficient described above. When two or more kinds of (b) compounds are contained, it is preferable that the molecular weight of the compound having the largest Db is within the above range. However, in the selection of (b) the compound, trace components having a content of 4% by mass or less in the ink shall be excluded.

[0036] The ratio ((a) / (b)) of the weight average molecular weight of (a) the resin to the molecular weight of (b) the compound described above is preferably 10 to 80. By setting such a ratio ((a) / (b)) to 10 or more, the weight average molecular weight of (a) the resin is sufficiently large and the entanglement becomes denser, so that the diffusibility of (b) the compound with respect to (a) the resin is suppressed, and Da can be made smaller. For this reason, elution of unreacted components from the ink cured film can be further suppressed. On the other hand, by setting the molecular weight ratio ((a) / (b)) to 80 or less, the ink viscosity during low shear can be lowered and the ink transferability can be further improved.

[0037] (b) The smaller the density G2 of the compound, the larger the volume per unit weight and the larger the volume of one molecule. The density G2 is 1.20 g / cm 3The following is preferable. Since the volume of the molecule of the (b) compound is sufficiently larger than the entangled state of the (a) resin, the diffusibility of the (b) compound with respect to the (a) resin is more suppressed, and Da can be made smaller. For this reason, elution of unreacted components from the ink cured film can be more suppressed. The density G2 is 1.18 g / cm 3 The following is more preferable. When two or more kinds of (b) compounds are contained, it is preferable that the density of the compound having the largest Db, that is, the compound having the largest diffusion coefficient, is within the above range. However, in the selection of the (b) compound having an ethylenically unsaturated group, trace components having a content of 4% by mass or less in the ink shall be excluded.

[0038] The density G2 of the (b) compound can be measured by the pycnometer method in the same manner as the density G1 of the (a) resin. More specifically, the (b) compound is separated from the ink by the above-described method, injected into the pycnometer up to the capacity limit, and the weight is measured. The density is calculated from the following formula from the measurement results, and the average value measured three times is taken as G2. ρ E =(m4 / V)+ρ a ρ E : Density of the compound having an ethylenically unsaturated group (g / cm 3 ) m4: Weight (g) of the pycnometer filled with the compound having an ethylenically unsaturated group V: Volume of the pycnometer (cm 3 ) ρ a : Density of air (g / cm 3 )

[0039] (a) The ratio (G2 / G1) of the density G2 of the compound having an ethylenically unsaturated group to the density G1 of the resin is preferably 1.03 or less. Since the volume of the molecule of the compound having an ethylenically unsaturated group (b) is sufficiently larger than the entangled state of the resin (a), the diffusibility of the compound having an ethylenically unsaturated group (b) with respect to the resin (a) is more suppressed, and Da can be made smaller. Therefore, elution of unreacted components from the ink cured film can be more suppressed. More preferably, G2 / G1 is 1.0 or less.

[0040] The ink according to the present invention preferably contains 20% by mass or more of the (b) compound, and the ink viscosity at low shear can be lowered to further improve the ink transferability. More preferably, the content of the (b) compound is 45% by mass or more. On the other hand, the content of the (b) compound is preferably 80% by mass or less, and the ink viscosity at high shear can be increased to further reduce ground contamination. When two or more kinds of the (b) compound are contained, the total content of the (b) compound is preferably within the above range.

[0041] The mass ratio ((a) / (b)) of the content of the resin (a) to the content of the (b) compound is preferably 0.15 or more, which can moderately increase the compatibility between the resin (a) and the (b) compound, increase the ink viscosity at high shear, and further suppress ground contamination. On the other hand, the mass ratio ((a) / (b)) is preferably 1.0 or less, which can increase the compatibility between the resin (a) and the (b) compound, lower the ink viscosity at low shear, and further improve the ink transferability. More preferably, the mass ratio ((a) / (b)) is 0.80 or less.

[0042] Examples of the (c) pigment include organic pigments and inorganic pigments. Examples of the organic pigments and inorganic pigments include those exemplified as organic pigments and inorganic pigments, respectively, in International Publication No. 2018 / 163942. Two or more of them may be contained.

[0043] The content of the (c) pigment in the ink is preferably 15 to 50% by mass.

[0044] The ink according to the present invention can contain an acylphosphine oxide compound. Examples of the acylphosphine oxide compound include those exemplified in International Publication No. 2018 / 163942. Two or more of them may be contained. When containing an acylphosphine oxide compound, the content is preferably 5% by mass or more and 10% by mass or less.

[0045] The ink according to the present invention can contain a sensitizer. Examples of the sensitizer include those exemplified in International Publication No. 2018 / 163942. Two or more of them may be contained. When containing a sensitizer, the content is preferably 3% by mass or more and 10% by mass or less.

[0046] The ink according to the present invention preferably contains a polymerization inhibitor. Examples of the polymerization inhibitor include those exemplified in International Publication No. 2018 / 163942. Two or more of them may be contained. When the ink according to the present invention contains a polymerization inhibitor, the content is preferably 0.001% by mass or more and 5% by mass or less.

[0047] The ink according to the present invention preferably contains a silicone liquid, an alkyl (meth) acrylate, a vegetable oil, a fatty acid ester derived from a vegetable oil, a hydrocarbon solvent, and / or a fluorocarbon. Two or more of these may be contained. Among these, a silicone liquid, an alkyl (meth) acrylate, a hydrocarbon solvent, and a fluorocarbon are more preferable. By containing these, soil stain can be more suppressed. Further, since the alkyl (meth) acrylate cures upon irradiation with active energy rays, the sensitivity to active energy rays and the water resistance of the ink cured film can be improved. Examples of the silicone liquid, the alkyl (meth) acrylate, the vegetable oil, the fatty acid ester derived from a vegetable oil, the hydrocarbon solvent, and the fluorocarbon are those exemplified in International Publication No. 2018 / 163942. The total content of the silicone liquid, the alkyl (meth) acrylate, the vegetable oil, the fatty acid ester derived from a vegetable oil, the hydrocarbon solvent, and the fluorocarbon in the ink according to the present invention is preferably 2% by mass or more and 5% by mass or less.

[0048] The ink according to the present invention preferably contains a pigment dispersant. By containing the pigment dispersant, (c) the dispersibility of the pigment can be improved and the ink transferability can be further improved. Examples of the pigment dispersant include those exemplified in International Publication No. 2018 / 163942. Two or more of them may be contained. The content of the pigment dispersant in the ink according to the present invention is preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (c) pigment.

[0049] The ink according to the present invention preferably contains a surfactant. By containing a surfactant, when performing lithographic printing with water, an appropriate amount of dampening water (generally said to be 10 to 20% by mass of the total amount of the ink) is taken in and emulsified, so that the repellency to the dampening water in the non-printing area is increased, and ground contamination can be more effectively suppressed. Examples of the surfactant include those exemplified in International Publication No. 2018 / 163942. Two or more of them may be contained. The content of the surfactant in the ink according to the present invention is preferably 0.1% by mass or more and 1% by mass or less.

[0050] The ink according to the present invention may contain additives such as wax, defoaming agent, transferability improver, leveling agent, etc., if necessary.

[0051] Next, a method for producing the ink according to the present invention will be described. The ink according to the present invention can be obtained by mixing and dispersing (a) a resin, (b) a compound, (c) a pigment, and, if necessary, other components. Prior to mixing and dispersing, each raw material may be dissolved at 5 to 100°C, or defoaming may be performed under vacuum or reduced pressure conditions during the process of mixing and dispersing and / or after mixing and dispersing. Examples of the mixing and dispersing apparatus include stirrers and kneaders such as kneaders, three-roll mills, ball mills, planetary ball mills, bead mills, roll mills, attritors, sand mills, gate mixers, paint shakers, homogenizers, and self-revolving and revolving stirrers.

[0052] Next, a method for producing a printed matter of the present invention will be described. The method for producing a printed matter of the present invention includes a step of transferring the ink according to the present invention described above onto a substrate and a step of irradiating active energy rays. Since the ink of the present invention cures by irradiation with active energy rays, a printed matter having a cured film of the ink can be obtained by the step of irradiating active energy rays.

[0053] First, the step of transferring the ink according to the present invention onto a substrate will be described.

[0054] Examples of the base material include art paper, coated paper, cast paper, synthetic paper, newsprint, plastic film, plastic film laminated paper, metal plate, metal vapor deposited paper, metal vapor deposited plastic film, etc. Two or more of these may be used. Examples of the plastic film include films made of polyethylene terephthalate, polyethylene, polyester, polyamide, polyimide, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc. Examples of the plastic film laminated paper include those in which the aforementioned plastic film is laminated on paper. Examples of the metal plate include plates made of zinc, copper, aluminum, etc. Examples of the metal vapor deposited paper and the metal vapor deposited plastic film include those in which the metal or its oxide is vapor deposited on paper or plastic film. Among these, plastic film, plastic film laminated paper, and metal vapor deposited plastic film are preferred for use in the present invention because they do not absorb ink and thus do not fix the ink by ink absorption, and the ink can be cured and fixed by irradiation with active energy rays.

[0055] The base material may be subjected to an easy adhesion treatment. By performing the easy adhesion treatment, the ink transferability to the base material can be improved. Examples of the easy adhesion treatment include surface treatments such as primer coating, corona discharge treatment, and plasma treatment, and formation of an easy adhesion layer.

[0056] When used for flexible packaging applications, the thickness of the base material is preferably 10 μm or more and 30 μm or less.

[0057] As the base material, either single sheets or roll films can be used. When using a thin film in flexible packaging applications, it is preferable to use a roll film and perform roll-to-roll transfer.

[0058] As a method for transferring the ink according to the present invention onto a substrate, for example, lithographic printing methods such as UV offset, EB offset, and RI tester can be mentioned. Among these, from the viewpoint of the fineness of the pattern, UV offset and EB offset are preferable, and EB offset is more preferable.

[0059] Next, the step of irradiating active energy rays will be described.

[0060] Examples of the active energy rays include ultraviolet rays and electron beams. Examples of the ultraviolet irradiation device include a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, and a light-emitting diode (LED). It is preferable from the viewpoint of power saving to use ultraviolet rays (LED-UV) using an LED that emits emission lines with a wavelength of 350 to 420 nm as a light source. As the electron beam, an energy beam of 100 to 500 eV is preferable.

[0061] Examples of the printing machine used in the method for manufacturing a printed matter of the present invention include a single cylinder type printing machine that is printed using an independent impression cylinder for each color, and a center impression type printing machine that prints a plurality of colors using a single impression cylinder. Since the center impression type printing machine has a short printing interval (distance) for each color, the time required for flattening after transferring the ink onto the substrate is short, so it has been difficult to increase the concentration in conventional inks. The ink of the present invention appropriately suppresses the ink viscosity at low shear, shortens the time required for flattening after transferring the ink onto the substrate, and is easily concentrated, so it is particularly preferably used in a center impression type printing machine. That is, in the present invention, it is preferable to perform the step of transferring the ink onto the substrate and the step of irradiating active energy rays using a center impression type printing machine.

[0062] In the method for manufacturing a printed matter of the present invention, the thickness of the ink cured film on the obtained printed matter is preferably 0.1 to 50 μm. By setting the film thickness to 0.1 μm or more, the color density of the printed matter can be moderately increased. On the other hand, by setting the film thickness to 50 μm or less, the curing reaction by active energy rays can be facilitated, the unreacted components in the ink cured film can be reduced, and the elution of the unreacted components from the ink cured film can be further suppressed.

Example

[0063] Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited thereto.

[0064] (Synthesis Example 1: (a) Resin 1) Into a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, 150 mol parts of propylene glycol monomethyl ether acetate as a solvent, 15 mol parts of styrene, 52 mol parts of ethyl acrylate, and 33 mol parts of acrylic acid were charged, and 1 mol part of 2,2'-azobis(2-methylbutyronitrile) was added as a polymerization initiator. A dropwise polymerization reaction was carried out while refluxing and stirring at 140 °C for 1.5 hours, and then the temperature was maintained for 1 hour. Thereafter, the temperature was raised to 160 °C, the solvent was distilled off while continuing stirring at normal pressure, and then the pressure was reduced to 6.7 MPa or less at the same temperature to distill off the solvent, obtaining Resin 1 having a weight average molecular weight of 23,000 and an acid value of 198 mgKOH / g.

[0065] (Synthesis Examples 2 to 11: (a) Resins 2 to 11) Resins 2 to 11 were obtained in the same manner as in Synthesis Example 1 except that the raw materials used and the amounts were changed as described in Table 1. The abbreviations in Table 1 are shown below. St: Styrene EA: Ethyl acrylate BA: Butyl acrylate PA: Pentyl acrylate 2EHA: 2-Ethylhexyl acrylate MMA: Methyl methacrylate AA: Acrylic acid MAA: Methacrylic acid ABN-E; 2,2'-Azobis(2-methylbutyronitrile) PGMEA: Propylene glycol monomethyl ether acetate

[0066]

Table 1

[0067] Other materials used in the examples and comparative examples are shown below. (b) Compound 1: Trimethylolpropane ethylene oxide modified triacrylate "Miramer" (registered trademark) M3190 (manufactured by MIWON). Number of polymerizable functional groups 3, molecular weight 692, density 1.12 g / cm 3 (b) Compound 2: Pentaerythritol ethylene oxide modified tetraacrylate "Miramer" (registered trademark) M4004 (manufactured by MIWON). Number of polymerizable functional groups 4, molecular weight 572, density 1.18 g / cm 3 (b) Compound 3: Diglycerin propylene oxide modified tetraacrylate (compound obtained by separating glycerin propylene oxide modified triacrylate from "EBECRYL" (registered trademark) 810 (manufactured by Daicel Allnex Co., Ltd.)). Number of polymerizable functional groups 4, molecular weight 905, density 1.07 g / cm 3 . (b) Compound 4: Lauryl acrylate (manufactured by Fujifilm Wako Pure Chemical Corporation). Number of polymerizable functional groups 1, molecular weight 240, density 0.88 g / cm 3 . (b) Compound 5: Dipentaerythritol hexaacrylate "Miramer" (registered trademark) M600 (manufactured by MIWON). Number of polymerizable functional groups 6, molecular weight 578, density 1.19 g / cm 3 . Pigment 1: "SYMULER" (registered trademark) BRILLIANT CARMINE 6B 393 (manufactured by DIC Corporation) Pigment 2: Mica A-11 (manufactured by Yamaguchi Mica Co., Ltd.).

[0068] Next, the raw materials, and the evaluation methods in the examples and comparative examples will be described.

[0069] (Molecular weight) (a) Weight-average molecular weight of the resin: (a) The resin was diluted with tetrahydrofuran so that the concentration became 0.25 mass%. The diluted solution was stirred at 100 rpm for 5 minutes using a mix rotor (MIX-ROTAR VMR-5, manufactured by AS ONE Corporation) to dissolve the resin, and the filtrate filtered using a 0.2 μm filter (Z227536-100EA, manufactured by SIGMA) was used as the measurement sample. For GPC, HLC-8220 (manufactured by Tosoh Corporation) was used, and columns were connected in the order of TSKgel SuperHM-H (manufactured by Tosoh Corporation), TSKgel SuperHM-H (manufactured by Tosoh Corporation), and TSKgel SuperH2000 (manufactured by Tosoh Corporation). RI detection was performed using the RI detector built into the GPC. The injection volume was 10 μL, the analysis time was 30 minutes, the flow rate was 0.4 mL / min, and the column temperature was 40°C. A calibration curve was created using a polystyrene standard substance, and the weight-average molecular weight of the measurement sample was calculated.

[0070] (b) Molecular weight of the compound: (b) The compound was diluted with tetrahydrofuran so that the concentration became 0.10 mass%. The diluted solution was stirred at 100 rpm for 5 minutes using a mix rotor (MIX-ROTAR VMR-5, manufactured by AS ONE Corporation) to dissolve the compound, and the filtrate filtered using a 0.2 μm filter (Z227536-100EA, manufactured by SIGMA) was used as the measurement sample. The mass spectrometer was LCMS-2020 (manufactured by Shimadzu Corporation), the column was Shim-packXR-C8 (manufactured by Shimadzu Corporation), and the mobile phase was acetonitrile: water: formic acid = 90:10:0.1 (mass%). The injection volume was 1.0 mL, the analysis time was 8 minutes, the flow rate was 1.0 mL / min, and the column temperature was 50°C.

[0071] (Density) (a) Density of resin: Measured in accordance with Method B (pycnometer method) in Section 5.2 of the test method in JIS K 7112:1999. The (a) resins prepared in Synthesis Examples 1 to 11 were each weighed in a pycnometer, and then a poor solvent was injected up to the volume limit as the immersion liquid, and the weight was measured. Next, all the samples in the pycnometer were taken out, dried, and then the immersion liquid was injected up to the volume limit, and the weight was measured. The density was calculated from the following formula based on the measurement results. ρ R = [m1 / (m1 + m3 - m2)] × ρ L ρ R : Density of resin (g / cm 3 ) m1: Weight of resin placed in the pycnometer (g) m2: Weight of the pycnometer filled with the immersion liquid with the sample (g) m3: Weight of the pycnometer filled with only the immersion liquid (g) ρ L : Density of the immersion liquid (g / cm 3 ) The above measurement was carried out 3 times, and the average value was taken as the density of the (a) resin.

[0072] (b) Density of compound: Measured in accordance with the density measurement method by the pycnometer method in Annex 2 of JIS K 7112:1999 - Plastics - Liquid Resins. Each of the above (b) compounds was injected into a pycnometer up to the volume limit, and the weight was measured. The density was calculated from the following formula based on the measurement results. ρ E = (m4 / V) + ρ a ρ E : Density of the compound having an ethylenically unsaturated group (g / cm 3 ) m4: Weight of the pycnometer filled with the compound having an ethylenically unsaturated group (g) V: Volume of the pycnometer (cm 3 ) ρ a : Density of air (g / cm 3 )) The above measurement was carried out 3 times, and the average value was taken as the density of the (b) compound.

[0073] (Acid value) (a) The acid value of the resin was measured by the neutralization titration method in accordance with Paragraph 3.1 of the test method of JIS K 0070:1992. 1.0 g of the (a) resin prepared in Synthesis Examples 1 to 11 was weighed into a 100 ml Erlenmeyer flask, and a few drops of a phenolphthalein solution as an indicator and 100 ml of ethanol were added, and the sample was sufficiently stirred on a water bath until it was completely dissolved. Next, it was titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point was determined when the red color of the indicator continued for 30 seconds. Then, the acid value was calculated by the following formula. A = [B × f × 5.611 / S] A: Acid value (mgKOH / g) B: Amount (ml) of 0.1 mol / l potassium hydroxide ethanol solution used for titration f: Factor of 0.1 mol / l potassium hydroxide ethanol solution (concentration correction coefficient) S: Mass (g) of the sample.

[0074] (Diffusion coefficient) The diffusion coefficient was calculated from the mean square displacement using the Forcite molecular dynamics calculation program of Materials Studio (manufactured by Accelrys, Inc.) with the NVT ensemble and performing a 10 ps calculation at 300K. COMPASSIII was used for the force field, and the Ewald method was used for the calculation of the long-range interactions of the van der Waals force and the electrostatic force.

[0075] The diffusion coefficient Da of the (b) compound with respect to the (a) resin was analyzed for each combination of the (a) resin and the (b) compound used in each Example and Comparative Example using a model in which the molecular weight of the (a) resin was 0.2 times the weight average molecular weight and the molecular weight of the (b) compound was 1.0 times the molecular weight, and the molecular number ratio was set to (a):(b) = 1:4. Each analysis was performed three times, and the average value was taken as Da.

[0076] The diffusion coefficient Db of the (b) compound with respect to polypropylene was calculated in the same manner as Da, except that the (a) resin used in each example and comparative example was replaced with polypropylene of the same molecular weight. Each analysis was performed three times, and the average value was taken as Db.

[0077] (Elution amount of unreacted components) A solid-image lithographic printing plate without water (TAC-VG5, manufactured by Toray Industries, Inc.) having a solid-image band of 400 mm in length (printing direction) × 900 mm in width (printing width direction) provided at the center of a printing plate of 854 mm in length (printing direction) × 1,070 mm in width (printing width direction) was mounted on a central impression type offset rotary printing press (CI-8, manufactured by Comexi), and using the inks obtained in each example and comparative example, printing was performed on a polyester film PTM12 (manufactured by Unitika Ltd., thickness 12 μm) at a printing speed of 200 m / min and an ink supply amount of 50% for 1,000 m. When the film thickness of the solid-printed ink cured film was measured using a contact type film thickness gauge, it was 3 μm. In the printed matter at the time of 1,000 m printing, a portion of the solid-printed ink cured film with a film thickness of 3 μm was cut into a 12 cm square, and the evaluation area was 100 cm 2 and set in a cylindrical single-sided elution device so that the printing surface became the elution surface, 100 ml of 95% by mass ethanol was injected, and it was stored in a constant temperature bath at 60°C for 5 hours. Thereafter, the ethanol was concentrated 10-fold, and the amount of ink components (unreacted components) eluted in the ethanol was measured by liquid chromatography-mass spectrometry (LC-MS).

[0078] (Ink transferability) Regarding the printed matter at the time of 1,000 m printing obtained in the measurement of the elution amount of the unreacted components, using a reflection densitometer (GretagMacbeth, SpectroEye, status E), with high-quality paper as the paper white (reference with a reflection density of 0), the density of the solid portion was measured to evaluate the ink transferability. The higher the density, the better the ink transferability.

[0079] (Background staining) Printing was performed in the same manner as the evaluation of the elution amount of the unreacted components, except that the ink supply amount was adjusted so that the density of the solid part was 1.6. For the printed matter at the time of 1,000 m printing, the density of the non-printing part located 1 cm in the printing direction from the center in the width direction was evaluated using a reflection densitometer in the same manner as the evaluation of the ink transferability. The lower the density, the more the background staining is suppressed.

[0080] (Example 1) 24 parts by mass of resin 1 and 54 parts by mass of compound 1 prepared in Synthesis Example 1 were weighed into a container, and while stirring at 500 rpm using a dispersing blade, they were heated and dissolved at 95 °C for 390 minutes to obtain a varnish. To the obtained varnish, 20 parts by weight of Pigment 1 and 2 parts by weight of Pigment 2 were weighed and added, and using a three-roll mill "EXAKT" (registered trademark) M-80S (manufactured by EXAKT), they were kneaded 3 times with a gap of 1 to obtain ink.

[0081] (Examples 2 to 12, Comparative Examples 1 to 3) Inks were obtained in the same manner as in Example 1, except that the components (a) to (c) used and the amounts were changed as described in Tables 2 to 4.

[0082] The evaluation results of each example and comparative example are shown in Tables 2 to 4.

[0083]

Table 2

[0084]

Table 3

[0085]

Table 4

Claims

1. An active energy ray-curable offset printing ink containing (a) a resin, (b) a compound having an ethylenically unsaturated group, and (c) a pigment, wherein the ratio (Da / Db) of the diffusion coefficient Da of the compound having an ethylenically unsaturated group with respect to the resin (a) to the diffusion coefficient Db of the compound having an ethylenically unsaturated group with respect to polypropylene is 0.9 or less.

2. The density G1 of the resin (a) is 1.11 to 1.30 g / cm ３ The active energy ray-curable offset printing ink according to claim 1, wherein the density G1 of the resin (a) is 1.11 to 1.30 g / cm

3. The active energy ray-curable offset printing ink according to claim 1 or 2, containing a copolymer containing (a-1) an alkyl (meth)acrylate and (a-2) styrene as copolymerization components in the resin (a).

4. The active energy ray-curable offset printing ink according to claim 3, wherein the ratio ((a-2) / (a-1)) of the content (mol%) of styrene ((a-2)) to the content (mol%) of the alkyl (meth)acrylate ((a-1)) in the copolymerization components is 0.20 to 1.

10.

5. The active energy ray-curable offset printing ink according to claim 3, wherein the alkyl group in the (a-1) alkyl (meth)acrylate has 1 to 6 carbon atoms.

6. The active energy ray-curable offset printing ink according to claim 1 or 2, wherein the resin (a) has a hydrophilic functional group.

7. The active energy ray-curable offset printing ink according to claim 1 or 2, wherein the ratio (G2 / G1) of the density G2 of the compound having an ethylenically unsaturated group (b) to the density G1 of the resin (a) is 1.03 or less.

8. The active energy ray-curable offset printing ink according to claim 1 or 2, wherein the compound having an ethylenically unsaturated group (b) has 3 to 6 ethylenically unsaturated groups.

9. The active energy ray-curable offset printing ink according to claim 1 or 2, wherein the ratio ((a) / (b)) of the weight average molecular weight (Mw) of the resin (a) to the molecular weight of the compound having an ethylenically unsaturated group (b) is 10 to 80.

10. The active energy ray-curable offset printing ink according to claim 1 or 2, wherein the acid value of the resin (a) is 100 to 250 g / KOHmg.

11. A method for manufacturing a printed matter, comprising a step of transferring the active energy ray-curable offset printing ink according to claim 1 or 2 onto a substrate, and a step of irradiating the transferred active energy ray-curable offset printing ink with active energy rays.

12. The method for manufacturing a printed matter according to claim 11, wherein a plastic film, a plastic film laminated paper, and / or a metal vapor-deposited plastic film is used as the substrate.

13. The method for manufacturing a printed matter according to claim 11, wherein the active energy rays are electron beams or ultraviolet rays.

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