Electron-beam–curable composition and laminate

Abstract

An electron-beam-curable composition comprising: a resin (A) having a weight-average molecular weight of 5,000-50,000; a (meth)acrylate compound (B) having a weight-average molecular weight of 700-3,000, wherein the weight-average molecular weight per (meth)acryloyl group is 100-300; and a pigment (C).

Description

Electron beam curable composition and laminate

[0001] An embodiment of the present invention relates to an electron beam curable composition and a laminate.

[0002] In recent years, the use of curing technology using active energy rays has expanded in the printing industry. Curing technology using active energy rays enables shortening of processing time through instant drying, reduction of environmental impact and improvement of work safety through non-VOC (non-VOC) content, and realization of strong coating film properties through crosslinking reactions.

[0003] The use of active energy ray curing technology began in the commercial printing field using paper substrates such as flyers and posters, and has expanded to various fields due to the development of printing technologies including printing machines and printing inks. Accordingly, the application of active energy ray curing technology is expanding to fields using various film substrates. For example, its use as a packaging material for packaged products such as packaging for food, cosmetics, and toys is expanding.

[0004] In particular, when packaging materials are used for food packaging, the use of active energy ray-curable compositions capable of suppressing migration is essential to ensure health safety. Regarding migration in packaging materials for food packaging (hereinafter also referred to as food packaging materials), various regulations have been established to ensure food packaging safety. In particular, the Swiss Federal Ordinance (Swiss Ordinance RS817.023.21 Annex 10) establishes a positive list (restrictions on usable raw materials) for packaging materials, including non-food contact inks and varnishes, and further regulates the allowable migration limit (SML) for each raw material. While the regulatory standards set by the Swiss Federal Ordinance are very strict, due to increasing consumer safety consciousness, these standards have become an important indicator as a global standard for food packaging materials in recent years.

[0005] In contrast, when conventional active energy ray-curable compositions are used in food packaging materials, it tends to be difficult to meet the above-mentioned SML regulatory level. Active energy ray-curable compositions are broadly classified into ultraviolet-curable compositions and electron beam-curable compositions from the viewpoint of reaction form. In particular, ultraviolet-curable compositions require a photopolymerization initiator, and are prone to migration problems due to the low-molecular-weight photopolymerization initiator. On the other hand, electron beam-curable compositions do not require a photopolymerization initiator because they utilize high-energy electron beams. Therefore, from the viewpoint of improving the migration problem, it is considered that electron beam-curable compositions can be preferably used in applications such as food packaging materials.

[0006] However, like ultraviolet-curable compositions, typical electron beam-curable compositions contain a (meth)acrylate monomer as the main component of the binder, and are prone to migration problems due to the low-molecular-weight (meth)acrylate monomer. Therefore, even when electron beam-curable compositions are used as inks, further investigations are required to improve migration.

[0007] Furthermore, in order to respond to the diversification and sophistication of consumer needs in recent years, laminates constituting packaging materials for packages have become more diverse and complex, and therefore, there is a demand for active energy ray-curable compositions that have good adhesion to various substrate structures and are capable of forming strong coatings.

[0008] However, in the development of active energy ray-curable compositions, designs that prioritize adhesion to various film substrates tend to result in a deterioration in film strength. On the other hand, designs that prioritize film strength tend to result in a deterioration in adhesion to various film substrates. Thus, there is a proposition that film strength and adhesion tend to be in a trade-off state.

[0009] A related problem is that, in the case of packaging materials for packages having a printed surface after being printed with active energy ray-curable ink, the printed surface of the packaging material can be scratched or peeled off due to vibrations and friction that occur during transportation by truck or the like, and a solution to this problem is desired.

[0010] Furthermore, in response to recent health safety and environmental regulations, the range of choices for raw materials that can be used as materials for active energy ray-curable compositions has been narrowed. In particular, active energy ray-curable compositions that do not contain persistent organic pollutants, such as tetrafluoroethylene, and that do not contain photopolymerization initiators from the viewpoints of health and safety are desired.

[0011] On the other hand, various printing methods are used in printing of actinic radiation-curable compositions, such as lithographic printing, flexographic printing, and resin letterpress printing. Lithographic printing includes wet lithographic printing, which uses dampening water to form an image by the repulsion of oil (ink) in the image area and water (dampening water) in the non-image area, and waterless lithographic printing, which uses a silicone layer in the non-image area to form an image by the repulsion of ink in the image area. Among these, wet lithographic printing, which has good workability, is preferably used.

[0012] Recently, in printing sites, there has been a growing demand for shorter delivery times, labor savings, and faster printing speeds with the aim of improving production efficiency and reducing costs. Therefore, there is a demand for printing inks that can stably produce high-quality printed materials at high speeds and over long periods of time without any problems. In particular, it is difficult for actinic radiation-curable compositions for film substrates to ensure the necessary viscoelasticity and emulsification performance when made into printing inks. Therefore, problems such as unstable concentration during high-speed printing and the tendency for smearing during printing have arisen, and solutions to these problems are desired.

[0013] Under these circumstances, inks and varnishes, which are active energy ray-curable compositions, have been investigated.

[0014] For example, Patent Document 1 discloses a urethane resin containing an alkyl monoalcohol compound, a polyol compound, and a polyisocyanate compound as essential reaction raw materials as a binder resin. However, a composition combining the disclosed binder resin with a (meth)acrylate monomer and a photopolymerization initiator tends to have insufficient adhesion to a film substrate.

[0015] Patent Document 2 discloses an electron beam curable composition containing a rosin-modified resin, a (meth)acrylate compound, and an extender pigment as essential components. The disclosed electron beam curable composition is expected to improve printability, but the scratch resistance and peel resistance due to vibration and friction during transportation are insufficient.

[0016] Patent Document 3 discloses an electron beam-curable composition containing, as essential components, an acrylate monomer, an acrylate oligomer, an inactive resin, an acrylated epoxidized vegetable oil, and a white pigment. However, the disclosed electron beam-curable composition was developed for use as a primer. Therefore, when used in water-based lithographic printing, in particular, the emulsification balance with the dampening water is poor. In addition, the binder resin must be made low-molecular-weight, which prevents the ink from achieving the necessary viscoelasticity. This makes it difficult to obtain high-quality printed matter stably over a long period of time.

[0017] Patent Document 4 discloses an active energy ray-curable resin composition containing, as essential components, a urethane (meth)acrylate resin having a specific weight-average molecular weight and two types of (meth)acrylate compounds having a mono- to di-functional group and a tri- or higher-functional group. However, the disclosed active energy ray-curable resin composition uses a low-molecular-weight (meth)acrylate compound as the (meth)acrylate compound other than the urethane (meth)acrylate resin. Therefore, when the composition is used as a printing ink, there is a concern that curability and migration properties may be deteriorated during high-speed printing. Furthermore, stability on the press and stability during emulsification during water-based lithographic printing tend to be deteriorated.

[0018] JP 2019-183012 A JP 2023-028276 A International Publication No. 2020 / 212488 International Publication No. 2020 / 209264

[0019] One embodiment of the present invention provides an electron beam-curable composition that has safety, such as low migration, and is usable as a packaging material for various packages, and that can form a film that has both excellent adhesion to a film substrate and excellent film strength, thereby reducing problems such as abrasion or peeling during transportation, and has good printability. Another embodiment of the present invention provides a laminate using the electron beam-curable composition of the above embodiment.

[0020] As a result of extensive research, the present inventors have found that the above problems can be solved by using the electron beam-curable composition described below, and have thus completed the present invention. Embodiments of the present invention are described below. However, the present invention is not limited to the following embodiments, and includes various embodiments.

[0021] <1> An electron beam-curable composition comprising: a resin (A) having a weight-average molecular weight of 5,000 to 50,000; a (meth)acrylate compound (B) having a weight-average molecular weight of 700 to 3,000 and a weight-average molecular weight per (meth)acryloyl group of 100 to 300; and a pigment (C).

[0022] <2> The electron beam-curable composition according to the above <1>, wherein the ratio of the content (mass%) of the (meth)acrylate compound (B) in the total mass of the composition to the content (mass%) of the resin (A) in the total mass of the composition is 0.5 to 8.0.

[0023] <3> The electron beam-curable composition according to <1> or <2> above, wherein the resin (A) includes at least one resin selected from the group consisting of a rosin-modified resin and a urethane (meth)acrylate resin.

[0024] <4> The electron beam-curable composition according to any one of <1> to <3> above, wherein the (meth)acrylate compound (B) includes an amine-modified (meth)acrylate.

[0025] <5> The electron beam-curable composition according to any one of <1> to <4>, wherein the (meth)acrylate compound (B) includes a polyester (meth)acrylate.

[0026] <6> The electron beam-curable composition according to any one of <1> to <5>, wherein the total content of the resin (A), the (meth)acrylate compound (B), and the pigment (C) is 60 to 90 mass % relative to the total mass of the composition.

[0027] <7> The electron beam-curable composition according to any one of the above <1> to <6>, which is substantially free of a photopolymerization initiator.

[0028] <8> The electron beam-curable composition according to any one of <1> to <7> above, which is substantially free of organic solvents.

[0029] <9> The electron beam-curable composition according to any one of <1> to <8> above, which is substantially free of polytetrafluoroethylene wax.

[0030] <9> A laminate comprising a substrate and a cured product of the electron beam-curable composition according to any one of <1> to <9> above.

[0031] <10> The laminate according to <9>, wherein the substrate is a film or paper.

[0032] <11> A method for producing the laminate, comprising: applying the electron beam-curable composition according to any one of <1> to <9> above onto a substrate to form a coating film; and irradiating the coating film with an electron beam at an acceleration voltage of 40 to 120 kV and an exposure dose of 10 to 60 kGy. The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-111823, filed on July 7, 2023, the entire disclosure of which is incorporated herein by reference.

[0033] According to an embodiment of the present invention, it is possible to provide an electron beam-curable composition that has safety, such as low migration, and is usable as a packaging material for various packages, and that can form a coating film that combines excellent adhesion to a film substrate with excellent film strength, thereby reducing problems such as abrasion or peeling during transportation and having good printability.In addition, it is possible to provide a laminate using the electron beam-curable composition of the above embodiment.

[0034] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described below, and various modifications are possible within the scope of the gist of the present invention.

[0035] In addition, the term "conjugated double bond" used in this specification refers to a bond in which multiple double bonds are alternately connected with single bonds sandwiched between them. However, the π-electron conjugated system contained in aromatic compounds is excluded from conjugated double bonds. Furthermore, in this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively.

[0036] Resin (A) The resin (A) in the electron beam-curable composition of this embodiment is a resin with a weight-average molecular weight of 5,000 to 50,000. As long as the weight-average molecular weight is 5,000 to 50,000, the type of resin is not particularly limited, and known resins can be used. However, resins that are compatible with and soluble in (meth)acrylate compounds are preferred. Adjusting the weight-average molecular weight of the resin to 5,000 or more facilitates the ink viscoelasticity required when the electron beam-curable composition is made into an ink, and facilitates the emulsification performance required for use in water-based lithographic printing. Furthermore, adjusting the weight-average molecular weight to 50,000 or less facilitates the adhesion to films. In one embodiment, the weight-average molecular weight of the resin (A) is preferably 10,000 to 25,000.

[0037] The resin (A) may have a weight average molecular weight within the above range, and may or may not contain a (meth)acryloyl group in the molecule.

[0038] Specific examples of the resin (A) include diallyl phthalate resin, rosin-modified resin, polyester resin, epoxy resin, urethane (meth)acrylate resin, polyester (meth)acrylate resin, styrene-acrylic polymer resin, petroleum resin, and allyl resin. In one embodiment, the resin (A) may comprise at least one selected from the group consisting of diallyl phthalate resin, rosin-modified resin, polyester resin, and urethane (meth)acrylate resin. In other embodiments, an allyl resin other than diallyl phthalate resin, such as a non-phthalate allyl resin, may also be used as the allyl resin. That is, in such an embodiment, the resin (A) may comprise at least one selected from the group consisting of diallyl phthalate resin, rosin-modified resin, polyester resin, urethane (meth)acrylate resin, and non-phthalate allyl resin.

[0039] In one embodiment, from the viewpoints of printability, film strength, and adhesion, the resin (A) preferably contains at least one selected from the group consisting of a rosin-modified resin and a urethane (meth)acrylate resin.

[0040] <Rosin-Modified Resin> In an embodiment of the present invention, a rosin-modified resin refers to a resin that contains a skeleton derived from rosin in the resin skeleton.

[0041] In one embodiment, the rosin-modified resin preferably comprises a reaction product of raw material components including rosins, a polybasic acid, and a polyol. In one embodiment, the weight-average molecular weight of the rosin-modified resin may be preferably 5,000 to 50,000, more preferably 5,400 to 46,000, and even more preferably 15,000 to 30,000.

[0042] In an embodiment of the present invention, rosins refer to monobasic acids having a cyclic diterpene skeleton, such as rosin acid, disproportionated rosin acid, hydrogenated rosin acid, or alkali metal salts of these compounds. Specific examples of rosins include abietic acid, which has a conjugated double bond, and its conjugated compounds, such as neoabietic acid, palustric acid, and levopimaric acid. Other specific examples include pimaric acid, isopimaric acid, sandaracopimaric acid, and dehydroabietic acid, which do not have a conjugated double bond. Examples of natural resins containing these rosins include gum rosin, wood rosin, and tall oil rosin.

[0043] Examples of polybasic acids include carboxylic acids having two or more carboxyl groups in one molecule and anhydrides thereof.

[0044] Examples of polybasic acids include 1,2,3,6-tetrahydrophthalic acid, 3-methyl-1,2,3,6-tetrahydrophthalic acid, 4-methyl-1,2,3,6-tetrahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, dodecenylsuccinic acid, alkenylsuccinic acids such as pentadecenylsuccinic acid, o-phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, crotonic acid, isocrotonic acid, and acid anhydrides thereof.

[0045] Examples of polyols include compounds having two or more hydroxyl groups in one molecule, such as dihydric alcohols and trihydric or higher alcohols.

[0046] The dihydric alcohol may have a linear, branched, or cyclic structure. For example, examples of linear alkylene dihydric alcohols include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2-dodecanediol, 1,14-tetradecanediol, 1,2-tetradecanediol, 1,16-hexadecanediol, and 1,2-hexadecanediol. Examples of branched alkylene dihydric alcohols include 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-dimethylpentanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, dimethylol octane, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,4-diethyl-1,5-pentanediol. Examples of cyclic alkylene dihydric alcohols include 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cycloheptanediol, tricyclodecane dimethanol, hydrogenated catechol, hydrogenated resorcinol, hydrogenated hydroquinone, etc. Further examples include polyether polyols and polyester polyols such as polyethylene glycol (n=2 to 20), polypropylene glycol (n=2 to 20), and polytetramethylene glycol (n=2 to 20).

[0047] Further, examples of trihydric or higher alcohols include glycerin, trimethylolpropane, pentaerythritol, 1,2,6-hexanetriol, 3-methylpentane-1,3,5-triol, hydroxymethylhexanediol, trimethylol octane, diglycerin, ditrimethylolpropane, dipentaerythritol, sorbitol, inositol, and tripentaerythritol.

[0048] <Urethane (meth)acrylate Resin> In the embodiment of the present invention, the urethane (meth)acrylate resin refers to a resin having a urethane bond and a (meth)acryloyl group, which is obtained by reacting an isocyanate group with a hydroxy group.

[0049] In an embodiment of the present invention, the urethane (meth)acrylate resin can be produced according to a method known in the art. For example, in one embodiment, the urethane (meth)acrylate resin may be a compound obtained by reacting a polyisocyanate, a (meth)acrylate having a hydroxyl group, and a polyol in a compounding ratio such that the isocyanate group is in excess.

[0050] In one embodiment, from the viewpoint of easily improving the physical properties of the coating film, the urethane (meth)acrylate resin is preferably a compound containing a polyester segment and / or a compound containing a polyether segment. Such a compound can be obtained by using a polyether polyol or a polyester polyol as the polyol in the reaction for producing the urethane (meth)acrylate resin. In one embodiment, the weight-average molecular weight of the urethane (meth)acrylate resin may be preferably 5,000 to 50,000, more preferably 5,200 to 46,000, and even more preferably 15,000 to 30,000.

[0051] Representative compounds that can be used as raw materials for urethane (meth)acrylate resins will be described below.

[0052] The polyisocyanate is not particularly limited, and examples thereof include tolylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, Examples of suitable diisocyanates include isocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate in which the carboxyl group of a dimer acid is converted to an isocyanate group. From the viewpoint of reaction control, bifunctional diisocyanates are preferred.

[0053] The (meth)acrylate compound having a hydroxyl group is not particularly limited, and examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, polyethylene glycol (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylates, glycerin (meth)acrylate, glycerin di(meth)acrylate, and the like. acrylate, diglycerin di(meth)acrylate, diglycerin tri(meth)acrylate, trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and the like.

[0054] Examples of polyols include glycols, polyether polyols, and polyester polyols.

[0055] Examples of glycols include compounds having two hydroxyl groups, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, and neopentyl glycol.

[0056] Examples of polyether polyols that can be used include those having two or more hydroxyl groups, such as polymers, copolymers, and graft copolymers of alkylene oxides such as tetrahydrofuran, ethylene oxide, propylene oxide, butylene oxide, oxacyclobutane, and oxacycloheptane, and polyether polyols obtained by condensation of hexanediol, methylhexanediol, heptanediol, octanediol, or mixtures thereof. Furthermore, glycols obtained by adding alkylene oxides such as ethylene oxide to bisphenols such as bisphenol A and bisphenol F can also be used.

[0057] Examples of polyester polyols include polyester polyols obtained by condensation reaction of a polyhydric alcohol component and a polybasic acid component.

[0058] As the polyhydric alcohol, at least one of a dihydric alcohol and a trihydric or higher alcohol can be used. The dihydric alcohol is not particularly limited, and linear, branched, or cyclic alkylene dihydric alcohols can be used. Examples of linear alkylene dihydric alcohols include 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2-dodecanediol, 1,14-tetradecanediol, 1,2-tetradecanediol, 1,16-hexadecanediol, and 1,2-hexadecanediol. Examples of branched alkylene dihydric alcohols include 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-dimethylpentanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, dimethylol octane, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,4-diethyl-1,5-pentanediol. Examples of cyclic alkylene dihydric alcohols include 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cycloheptanediol, tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol S, hydrogenated catechol, hydrogenated resorcinol, and hydrogenated hydroquinone.

[0059] The trihydric or higher polyhydric alcohol is not particularly limited, and examples thereof include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerin, ditrimethylolpropane, sorbitan, sorbitol, dipentaerythritol, inositol, and tripentaerythritol.

[0060] The polybasic acid is not particularly limited and may be either aliphatic or alicyclic. Examples of the aliphatic polybasic acid include alkenylsuccinic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, dodecenylsuccinic acid, and pentadecenylsuccinic acid. Examples of the aromatic polybasic acid include isophthalic acid, isophthalic acid, terephthalic acid, himic acid, 3-methylhimic acid, 4-methylhimic acid, trimellitic acid, pyromellitic acid, 1,8-naphthalic acid, and anhydrides thereof. Alicyclic polybasic acids include 1,2,3,6-tetrahydrophthalic acid, 3-methyl-1,2,3,6-tetrahydrophthalic acid, 4-methyl-1,2,3,6-tetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, and anhydrides thereof.

[0061] Furthermore, compounds having three or more hydroxyl groups, such as glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, and methyl glucoside, can also be used as polyhydric alcohols.

[0062] Here, the above-mentioned polyols can be used without any particular limitation. They may be used alone or in combination of two or more depending on their respective characteristics. For example, from the viewpoint of the transparency and moist heat resistance of the coating film, it is preferable to use polyether polyols, and it is particularly preferable to mainly use polyols having a polypropylene glycol skeleton. Furthermore, from the viewpoint of adhesive strength and heat resistance, it is preferable to use polyester polyols.

[0063] <(Meth)acrylate Compound (B)> In one embodiment of the present invention, the (meth)acrylate compound (B) is a (meth)acrylate compound having a weight-average molecular weight of 700 to 3,000 and a weight-average molecular weight per (meth)acryloyl group of 100 to 300. The weight-average molecular weight of the (meth)acrylate compound (B) may be preferably 750 to 2,500, more preferably 800 to 2,000, even more preferably 900 to 1,800, and particularly preferably 1,000 to 1,700. When the weight-average molecular weight and the weight-average molecular weight per (meth)acryloyl group are within the above ranges, an excellent balance of low migration, film strength, and adhesion is achieved.

[0064] In one embodiment, the (meth)acrylate compound (B) can be suitably a (meth)acrylate compound having a weight-average molecular weight of 700 to 3,000 and a weight-average molecular weight per (meth)acryloyl group of 100 to 300. More preferably, one or more compounds selected from the group consisting of amine-modified (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, silicone (meth)acrylates, epoxy (meth)acrylates, and epoxidized vegetable oil (meth)acrylates can be used. In one embodiment, the (meth)acrylate compound (B) preferably includes an amine-modified (meth)acrylate and / or a polyester (meth)acrylate.

[0065] In one embodiment, the amine-modified (meth)acrylate is a (meth)acrylate compound having one or more amino groups in the molecule.

[0066] In one embodiment, the amine-modified (meth)acrylate preferably has an amine equivalent of 400 to 2,500. When the amine equivalent is 400 to 2,500, the surface curability, film strength, and background scumming during water-based lithographic printing are all improved.

[0067] In the above embodiment, the amine equivalent can be calculated as the molecular weight per active hydrogen derived from the amine in the amine-modified (meth)acrylate.

[0068] In one embodiment, the amine-modified (meth)acrylate is preferably contained in an amount of 0.5 to 10% by mass based on the total mass of the electron beam-curable composition, which provides good surface curability, film strength, and background scumming during water-based lithographic printing.

[0069] In one embodiment, examples of the amine-modified (meth)acrylate include EBECRYL LEO 10553 (weight average molecular weight: 780, number of acryloyl groups per molecule: 4, weight average molecular weight per acryloyl group: 195) and EBECRYL 80 (weight average molecular weight: 1000, number of acryloyl groups per molecule: 4, weight average molecular weight per acryloyl group: 250), manufactured by DAICEL-ALLNEX Corporation.

[0070] In one embodiment of the present invention, the polyester (meth)acrylate is a (meth)acrylate compound having a polyester structure in the molecule (excluding the case where an amino group is contained).

[0071] In one embodiment, the polyester (meth)acrylate desirably has 3 to 10 acryloyl groups in the molecule.

[0072] In one embodiment, the polyester (meth)acrylate is preferably contained in an amount of 10 to 50% by mass based on the total mass of the electron beam-curable composition, which results in good adhesion, viscoelasticity, and emulsifiability during water-based lithographic printing.

[0073] In one embodiment of the present invention, the polyester (meth)acrylate may be, for example, EBECRYL manufactured by DAICEL-ALNEX. Examples thereof include LEO10801 (weight average molecular weight 1,500, number of acryloyl groups per molecule: 6), EBECRYL450 (weight average molecular weight 1,600, number of acryloyl groups per molecule: 6), EBECRYL800 (weight average molecular weight 780, number of acryloyl groups per molecule: 4), EBECRYL810 (weight average molecular weight 1,000, number of acryloyl groups per molecule: 4), EBECRYL812 (weight average molecular weight 800, number of acryloyl groups per molecule: 3), EBECRYL846 (weight average molecular weight 1,100, number of acryloyl groups per molecule: 6), and EBECRYL870 (weight average molecular weight 1,500, number of acryloyl groups per molecule: 6).

[0074] In one embodiment, from the viewpoint of the viscoelasticity of the ink, it is more preferable to use the (meth)acrylate compound (B) in combination with the amine-modified (meth)acrylate and the polyester acrylate.

[0075] In one embodiment, the (meth)acrylate compound (B) may be a polyether (meth)acrylate, a urethane (meth)acrylate, a silicone (meth)acrylate, an epoxy (meth)acrylate, or an epoxidized vegetable oil (meth)acrylate. Known materials may be used as long as they have a weight-average molecular weight of 700 to 3,000 and a weight-average molecular weight per (meth)acryloyl group of 100 to 300. Modified versions of these polyether (meth)acrylates, urethane (meth)acrylates, silicone (meth)acrylates, epoxy (meth)acrylates, and epoxidized vegetable oil (meth)acrylates may also be used.

[0076] In one embodiment of the present invention, the ratio (B / A) of the content (A mass%) of the resin (A) to the content (B mass%) of the (meth)acrylate compound (B) in the total mass of the composition is preferably 0.5 to 8.0, and more preferably 2.0 to 4.0. When the ratio (B / A) of the content (mass%) of the resin (A) to the (meth)acrylate compound (B) in the total mass of the composition is 0.5 to 8.0, it is possible to achieve both the necessary adhesion and the viscoelasticity of the ink when made into a waterborne lithographic printing ink.

[0077] In an embodiment of the present invention, the pigment (C) may be a colored pigment or an extender pigment. Colored pigments are broadly classified into white pigments and pigments having other colors. Colored pigments may be either inorganic pigments or organic pigments. By using organic pigments, white inks and colored inks having other colors can be prepared.

[0078] In one embodiment, specific examples of inorganic pigments among the colored pigments include yellow lead, zinc yellow, iron blue, cadmium red, titanium oxide, zinc white, red iron oxide, ultramarine, carbon black, graphite, and aluminum powder.

[0079] In one embodiment, specific examples of organic pigments among the colored pigments include soluble azo pigments such as β-naphthol, β-oxynaphthoic acid, β-oxynaphthoic acid allylide, acetoacetic acid allylide, and pyrazolone; insoluble azo pigments such as β-naphthol, β-oxynaphthoic acid allylide, acetoacetic acid allylide monoazo, acetoacetic acid allylide disazo, and pyrazolone; copper phthalocyanine blue; halogenated (chlorinated or brominated) azo pigments; ) phthalocyanine pigments such as copper phthalocyanine blue, sulfonated copper phthalocyanine blue, and metal-free phthalocyanine; polycyclic pigments and heterocyclic pigments such as quinacridones, dioxazines, threnes (pyranthrones, anthanthrones, indanthrones, anthrapyrimidines, flavanthrones, thioindigos, anthraquinones, perinones, and perylenes), isoindolinones, metal complexes, and quinophthalones.

[0080] In one embodiment, the color pigment may be used alone or in combination of two or more thereof, or may be used in combination with one or more extender pigments described below.

[0081] In one embodiment, the content of the color pigment is preferably 2 to 30 mass %, more preferably 5 to 25 mass %, of the total mass of the electron beam-curable composition for a color ink. Furthermore, it is preferable that the content of titanium oxide is 30 to 70 mass %, more preferably 40 to 60 mass %, of the total mass of the electron beam-curable composition for a white ink. Furthermore, when a transparent ink (also called a varnish) and a dilution medium are prepared using an extender pigment as described below, the electron beam-curable composition does not need to contain a color pigment.

[0082] In one embodiment of the present invention, the extender pigment refers to a pigment that does not have coloring power and is distinguished from the colored pigments described above. Specific examples of the extender pigment in this embodiment of the present invention include barium sulfate, alumina white, calcium carbonate, magnesium carbonate, aluminum silicate, magnesium silicate, silicon dioxide, and aluminum hydroxide. These may be used alone or in combination of two or more.

[0083] In one embodiment, when the electron beam-curable composition is used as a color ink or a white ink (sometimes collectively referred to as "ink"), the content of the extender pigment is preferably adjusted depending on the intended purpose. For example, for the purpose of improving the fluidity and misting resistance of the ink, it is preferable to use an extender pigment in an amount of 5 mass% or less based on the total mass of the electron beam-curable composition. In one embodiment, no extender pigment is required when preparing the ink. On the other hand, when the electron beam-curable composition is used as a transparent ink (varnish), it is preferable to adjust the content of the extender pigment depending on the intended purpose. In one embodiment, it is preferable to use an extender pigment in an amount of 30 mass% or less based on the total mass of the electron beam-curable composition (varnish). In an embodiment of a varnish, the content of the extender pigment may be preferably 0.1 to 30 mass%, more preferably 0.5 to 20 mass%, and even more preferably 1 to 10 mass%.

[0084] In one embodiment of the present invention, the total content of the resin (A), the (meth)acrylate compound (B), and the pigment (C) may be 60 to 90% by mass, based on the total mass of the electron beam-curable composition. When the total content of the resin (A), the (meth)acrylate compound (B), and the pigment (C) is 60 to 90% by mass, based on the total mass of the composition, the necessary printability, such as viscoelasticity, fluidity, and transferability, required for waterborne lithographic printing can be easily obtained.

[0085] When the electron beam-curable composition of the above embodiment is used as a color ink, the total content of (A), (B), and (C) is preferably 60 to 80% by mass, and more preferably 65 to 75% by mass. When the electron beam-curable composition of the above embodiment is used as a white ink, the total content of (A), (B), and (C) is preferably 70 to 90% by mass, and more preferably 75 to 85% by mass. When the electron beam-curable composition of the above embodiment is used as a varnish or medium, the total content of (A), (B), and (C) is preferably 60 to 80% by mass, and more preferably 65 to 75% by mass.

[0086] In the above embodiment, it is preferable that the composition contains, as a component other than (A), (B), and (C), a (meth)acrylate compound different from (A) and (meth)acrylate compound (B) (hereinafter referred to as "other (meth)acrylate compound"). In the above embodiment, the content of the other (meth)acrylate compound may be 10 to 40 mass% with respect to the total mass of the electron beam curable composition. However, from the viewpoint of suppressing migration, it is preferable to use a compound having a weight-average molecular weight of 500 or more as the other (meth)acrylate compound. When a compound having a weight-average molecular weight of less than 500 is used as the other (meth)acrylate compound, its content is preferably 25 mass% or less, as described below.

[0087] In the above embodiment, the other (meth)acrylate compounds can be appropriately selected depending on the required properties of the cured film, and may be used alone or in combination of two or more. In the above embodiment, from the viewpoints of curability and low migration, the other (meth)acrylate compounds preferably have a weight average molecular weight of 500 or more and are composed of tri- or higher functional (meth)acrylate compounds.

[0088] (Electron beam curable varnish) In one embodiment, the electron beam curable composition can be produced by mixing the resin (A), the (meth)acrylate compound (B), and the pigment (C). In another embodiment, the electron beam curable composition can also be produced using an electron beam curable varnish containing the resin (A) described below.

[0089] The electron beam-curable varnish can be prepared using a resin (A) and a (meth)acrylate compound. Although not particularly limited, the electron beam-curable varnish preferably contains 10 to 80 mass% of the resin (A) and 20 to 90 mass% of the (meth)acrylate compound, based on the total mass of the varnish. More preferably, the electron beam-curable varnish may contain 20 to 70 mass% of the resin (A) and 30 to 80 mass% of the (meth)acrylate compound.

[0090] In the above-described embodiment of the electron beam-curable varnish, the (meth)acrylate compound may be any compound capable of adjusting the viscosity of the varnish to the desired range, and both the (meth)acrylate compound (B) and other (meth)acrylate compounds (i.e., different from the (meth)acrylate compound (B)) can be used. In one embodiment, the electron beam-curable varnish may be prepared using the resin (A) and a (meth)acrylate compound (different from the (meth)acrylate compound (B)). In such an embodiment, the electron beam-curable composition can be produced by further adding the (meth)acrylate compound (B) and the pigment (C) to the above-described varnish and mixing them. The blending amount of the varnish is preferably adjusted in consideration of the content of the resin (A) in the varnish so that the ratio (B / A) of the content of the resin (A) to the content of the (meth)acrylate compound (B) in the electron beam-curable composition is within a predetermined range.

[0091] In one embodiment, the (meth)acrylate compounds other than the resin (A) and the (meth)acrylate compound (B) used when preparing the electron beam-curable varnish and the electron beam-curable composition (other (meth)(meth)acrylate compounds) preferably have a weight-average molecular weight of 500 or more, from the viewpoint of ensuring low migration. The weight-average molecular weight of the (meth)acrylate compound may more preferably be 550 or more, even more preferably 650 or more, and even more preferably 750 or more. However, this embodiment does not exclude the use of (meth)acrylate compounds having a weight-average molecular weight of less than 500. In one embodiment, the electron beam-curable varnish and the electron beam-curable composition may contain a (meth)acrylate compound having a weight-average molecular weight of less than 500.

[0092] In one embodiment, the content of the (meth)acrylate compound having a weight-average molecular weight of less than 500 may be preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the total mass of the composition. The content may even be 0% by mass. When the content of the (meth)acrylate compound having a weight-average molecular weight of less than 500 is adjusted to fall within the above range, it becomes easy to ensure low migration properties.

[0093] Specific examples of (meth)acrylate compounds having a weight average molecular weight of less than 500 are as follows, but are not particularly limited thereto: monofunctional (meth)acrylate compounds such as 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, β-carboxylethyl (meth)acrylate, 4-tert-butylcyclohexanol (meth)acrylate, tetrahydrofurfuryl acrylate, alkoxylated tetrahydrofurfuryl acrylate, caprolactone (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isoamyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, isodecyl (meth)acrylate, 3,3,5-trimethylcyclohexanol (meth)acrylate, and the like. ) acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (oxyethyl) (meth)acrylate, 1,4-cyclohexanedimethanol (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, benzyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, acryloylmorpholine, N-vinylcarbazole, 1-vinylimidazole, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, N-vinylformamide, and the like.

[0094] Examples of bifunctional (meth)acrylate compounds include hexanediol diacrylate, tripropylene glycol diacrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,2-dodecanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol (200) di(meth)acrylate, polyethylene glycol (300) di(meth)acrylate, and hydrochloric acid. Examples of the di(meth)acrylate include neopentyl glycol xypivalate di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, EO-modified 1,6-hexanediol di(meth)acrylate, PO-modified neopentyl glycol di(meth)acrylate, (neopentyl glycol-modified) trimethylolpropane di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, dicyclopentanyl di(meth)acrylate, and tris(2-hydroxyethyl)isocyanurate di(meth)acrylate.

[0095] Examples of the trifunctional or higher (meth)acrylate compound include trimethylolpropane triacrylate, trimethylolpropane EO-modified (3 mol) triacrylate, trimethylolpropane PO-modified (3 mol) triacrylate, pentaerythritol triacrylate, glycerin PO-modified (3 mol) triacrylate, ditrimethylolpropane tetraacrylate, and pentaerythritol tetraacrylate.

[0096] As the (meth)acrylate compound having a weight average molecular weight of less than 500, one of the exemplified compounds may be used alone, or two or more may be used in combination. In one embodiment, it is preferable to use a polyfunctional (meth)acrylate. As the polyfunctional (meth)acrylate, it is preferable to use at least one of a bifunctional (meth)acrylate compound and a trifunctional or higher functional (meth)acrylate compound, and it is more preferable to use a trifunctional or higher functional (meth)acrylate compound.

[0097] The electron beam-curable varnish of the above embodiment may contain, in addition to the above components, a polymerization inhibitor, as described below. In such an embodiment, the polymerization inhibitor can be added and used by a conventional method. When a polymerization inhibitor is added to the varnish, the amount of the polymerization inhibitor added is preferably 3% by mass or less, and more preferably 0.01 to 1% by mass, based on the total mass of the electron beam-curable varnish.

[0098] In an embodiment of the present invention, the electron beam-curable varnish can be produced by mixing the above components at a temperature between room temperature and 160°C. For example, it can be produced by mixing resin (A) containing at least one selected from the group consisting of diallyl phthalate resin, rosin-modified resin, polyester resin, urethane (meth)acrylate resin, and non-phthalate allyl resin not containing a phthalate structure, with a polyfunctional (meth)acrylate compound such as dipentaerythritol hexaacrylate, and a polymerization inhibitor containing hydroquinone. In one embodiment, for example, a varnish obtained by heating and melting a rosin-modified resin, dipentaerythritol hexaacrylate, and hydroquinone at a temperature of 100°C can be suitably used.

[0099] (Polymerization Inhibitor) In one embodiment of the present invention, the electron beam curable composition may further contain a polymerization inhibitor in addition to the above components. In such an embodiment, the polymerization inhibitor can be added and used by a conventional method. When a polymerization inhibitor is added, in order not to inhibit curability, the amount of the polymerization inhibitor added is preferably 3% by mass or less, and more preferably in the range of 0.01 to 1% by mass, based on the total mass of the electron beam curable composition.

[0100] Specific examples of polymerization inhibitors include (alkyl)phenols, hydroquinone, catechol, resorcinol, p-methoxyphenol, t-butylcatechol, t-butylhydroquinone, pyrogallol, 1,1-picrylhydrazyl, phenothiazine, p-benzoquinone, nitrosobenzene, 2,5-di-tert-butyl-p-benzoquinone, dithiobenzoyl disulfide, picric acid, cupferron, aluminum N-nitrosophenylhydroxylamine, tri-p-nitrophenylmethyl, N-(3-oxyanilino-1,3-dimethylbutylidene)aniline oxide, dibutyl cresol, cyclohexanone oxime cresol, guaiacol, o-isopropylphenol, butyraldoxime, methyl ethyl ketoxime, cyclohexanone oxime, and di-t-butyl-7-phenylquinone methide.

[0101] In particular, compounds having two hydrocarbon groups at each of the 2- and 6-positions on the piperidine ring (four in total) are preferred. More specifically, it is preferable to use one or more compounds selected from hindered amines such as 2,2,6,6-tetraalkylpiperidine derivatives, 2,2,6,6-tetramethylpiperidine derivatives, 1-alkyl-2,2,6,6-tetramethylpiperidine derivatives, and 1-hydro-2,2,6,6-tetramethylpiperidine derivatives. When such compounds are used, the curing reaction in a printing press can be inhibited, and excellent storage stability can be easily achieved. The above compounds are also commercially available. For example, one example is "Polystop 7300P" (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a product of Hakuto Co., Ltd.

[0102] (Various Additives) In one embodiment of the present invention, the electron beam curable composition may further contain various additives such as a viscoelasticity modifier, a dispersant, an anti-friction agent, an anti-blocking agent, and a slip agent depending on the purpose. The various additives can be added to the composition by a conventional method. When various additives are added to the composition, it is preferable to adjust the amount to a range that does not inhibit the effects of other components. The amount of the various additives is preferably 5 mass % or less based on the total mass of the electron beam curable composition.

[0103] On the other hand, in recent years, there has been concern about global pollution caused by persistent organic pollutants that are difficult to decompose, highly accumulative, long-distance mobile, and harmful (to human health and ecosystems). For example, regulations are being implemented, as exemplified by the Stockholm Convention on Persistent Organic Pollutants (POPs Convention), which came into effect in May 2004. Polytetrafluoroethylene wax is used as an anti-friction agent for printing inks, but it may contain persistent organic pollutants such as PFAS. Therefore, it is preferable that the electron beam-curable composition of one embodiment of the present invention is substantially free of polytetrafluoroethylene wax.

[0104] Here, in the embodiments of the present invention, "substantially free" means that the target component is not intentionally added and the content due to unintentional addition is less than 1% by mass. Unintentional addition includes trace amounts of the component in each raw material, contamination during the composition manufacturing process, and the process of producing printed matter.

[0105] In one embodiment of the present invention, the electron beam curable composition is substantially free of organic solvents. There is a concern that organic solvents used as viscosity modifiers in printing inks may contain MOSH / MOAH, which are persistent organic pollutants. Furthermore, the absence of volatile components (non-VOC) is expected to reduce the environmental impact and improve work safety. For these reasons, in an embodiment of the present invention, it is preferable that the electron beam curable composition is substantially free of organic solvents.

[0106] In one embodiment of the present invention, the electron beam-curable composition is substantially free of a photopolymerization initiator. A photopolymerization initiator is expected to exhibit and improve the curability of an active energy beam-curable composition. However, in the packaging market, particularly in food packaging materials, toiletry packaging materials, and medical packaging materials, there is a concern that migration of photopolymerization initiator components may reduce safety and quality. For these reasons, in an embodiment of the present invention, it is preferable that the electron beam-curable composition is substantially free of a photopolymerization initiator.

[0107] In one embodiment of the present invention, from the viewpoint of carbon neutrality, raw materials derived from biomass using renewable resources such as plants can be preferably used as the various raw materials used in the electron beam curable composition.

[0108] In one embodiment of the present invention, when the electron beam-curable composition is used as a lithographic printing ink, the ink can be produced by flushing, milling, and mixing the above-mentioned components under temperature conditions between room temperature and 120° C. To produce the ink, it is preferable to use various equipment such as a kneader, a three-roll mill, an attritor, a sand mill, or a gate mixer. In producing the ink, the resin (A) may be added in the form of the resin (A) itself, or in the form of an electron beam-curable varnish containing the resin (A).

[0109] <Laminate> A laminate according to one embodiment of the present invention has a substrate and a printed layer formed on at least one main surface of the substrate and composed of a cured product of the electron beam-curable composition according to the above embodiment. In one embodiment of the present invention, when the electron beam-curable composition is an electron beam-curable ink, the laminate is obtained by printing the electron beam-curable ink on the substrate to form a coating film, and curing this coating film with an electron beam. Furthermore, when the electron beam-curable composition is an electron beam-curable varnish, the laminate is obtained by printing the electron beam-curable varnish on the substrate, or by printing the electron beam-curable varnish on a printed material on which ink has been printed on a substrate to form a coating film, and curing this coating film with an electron beam.

[0110] In the above embodiment, the substrate that can be used is preferably a film-like substrate. Examples include polyolefin substrates such as polyethylene and polypropylene, polyester substrates such as polyethylene terephthalate and polylactic acid, polycarbonate substrates, polystyrene-based substrates such as polystyrene, AS resin, and ABS resin, nylon substrates, polyamide substrates, polyvinyl chloride substrates, polyvinylidene chloride substrates, cellophane substrates, paper substrates, aluminum substrates, and film-like substrates made of composite materials thereof. Furthermore, vapor-deposited substrates in which inorganic compounds such as silica, alumina, and aluminum are vapor-deposited onto a polyethylene terephthalate substrate or a nylon substrate can also be used as the substrate. The vapor-deposited surface may further be coated with polyvinyl alcohol or the like. The printed surface of the substrate (the surface in contact with the printing layer) is preferably subjected to an adhesion-enhancing treatment. Examples of adhesion-enhancing treatments include corona discharge treatment, ultraviolet / ozone treatment, plasma treatment, oxygen plasma treatment, and primer treatment. Furthermore, if sufficient adhesion cannot be obtained with a polyethylene terephthalate substrate, an acrylic coating treatment, polyester treatment, polyvinylidene chloride treatment, or the like may be performed.

[0111] A paper substrate may be used as the substrate. The paper substrate may be ordinary paper, cardboard, or the like. There is no particular specification for the thickness of the paper substrate, but for example, it may be 0.2 mm to 1.0 mm, 20 to 150 g / m ２ The above-mentioned materials can be used, and the printing surface may be subjected to an easy-adhesion treatment. The paper substrate may be subjected to a vapor deposition treatment of a metal such as aluminum for the purpose of imparting design features. The surface may also be subjected to a surface coating treatment with acrylic resin, urethane resin, polyester resin, polyolefin resin, or other resin, and may further be subjected to a surface treatment such as corona treatment. Examples include coated paper and art paper.

[0112] In one embodiment of the present invention, the printing method for the electron beam-curable composition is not particularly limited, and known methods can be used. When the electron beam-curable composition is an ink, specific methods that can be used include wet offset printing (normal lithographic printing using dampening water), waterless offset printing (lithographic printing without dampening water), resin relief printing, and screen printing. Of these, it is preferable to use offset printing, and it is more preferable to use wet offset printing.

[0113] Similarly, when the electron beam-curable composition is a varnish, suitable applications include aqueous offset printing, waterless offset printing, resin letterpress printing, and screen printing. In addition, by adjusting the viscoelasticity, various printing methods such as flexographic printing, gravure printing, and inkjet printing, and coating with various coaters can be selected.

[0114] In one embodiment, the electron beam-curable composition is printed by various printing methods (after a coating film of the composition is formed), and then the coating film is cured through an electron beam irradiator to form a printed layer. The electron beam used for curing is preferably selected in consideration of the balance between damage to the substrate, such as a film, and the curability of the electron beam-curable composition. In one embodiment, it is desirable to irradiate with electron beams adjusted under conditions of an acceleration voltage of 40 to 120 kV, preferably 60 to 110 kV, and an exposure dose of 10 to 60 kGy, more preferably 15 to 45 kGy. An exposure dose of 10 to 60 kGy provides sufficient film strength and suppresses problems due to damage to the film, such as a decrease in film strength, odor, and yellowing.

[0115] The electron beam-curable composition of the above embodiment can be suitably used to form a printed layer on various substrates. It can also be used to form printed materials such as printed materials for forms, printed materials for various books, printed materials for various packaging such as carton paper, printed materials for various plastics, printed materials for stickers / labels, fine art prints, and printed materials for metal (fine art prints, printed materials for beverage cans, printed materials for canned food, etc.). In one embodiment, the electron beam-curable composition can be suitably used as an ink or varnish for forming a packaging material for food packages (hereinafter also referred to as a food packaging material).

[0116] One embodiment of the present invention relates to a method for producing a laminate having a substrate and a layer formed on the substrate and composed of a cured product of an electron beam-curable composition. This production method includes printing the electron beam-curable composition of the above embodiment onto the substrate to form a coating film, and irradiating the coating film with an electron beam to cure it. In the above embodiment, the coating film is preferably cured by irradiating it with an electron beam under conditions of an acceleration voltage of 40 to 120 kV and an exposure dose of 10 to 60 kGy. The electron beam-curable composition preferably comprises: a resin (A) having a weight-average molecular weight of 5,000 to 50,000; a (meth)acrylate compound (B) having a weight-average molecular weight of 700 to 3,000 and a weight-average molecular weight per (meth)acryloyl group of 100 to 300; and a pigment (C), wherein the resin (A) comprises one or more compounds selected from the group consisting of rosin-modified resins, urethane (meth)acrylate resins, polyester resins, and diallyl phthalate resins; and the (meth)acrylate compound (B) comprises one or more compounds selected from the group consisting of amine-modified (meth)acrylates and polyester (meth)acrylates.

[0117] In one embodiment, the laminate may have a structure used in food packaging applications. For example, it may be a surface-printed laminate having a printed layer formed from an ink or varnish of an electron beam-curable composition on one side of a substrate film, and a metal foil, various films, a sealant layer, or the like, on the other side of the film via an adhesive layer. In one embodiment, the food packaging material may be processed into various package shapes, such as a lid shape for a container, or a bag-like shape such as a pouch.

[0118] In a surface-printed laminate, the printed layer forms the outermost layer of the food packaging material (package). Therefore, by improving the film strength of the printed layer formed from the ink or varnish of the electron beam-curable composition of the above embodiment, problems such as package wear and breakage due to vibration and friction during transportation can be easily alleviated. In this way, the benefits of improved film strength are significant in a surface-printed laminate. However, the laminate is not limited to a surface-printed form and may also be a reverse-printed form. A reverse-printed laminate has a structure in which a film or the like is further laminated on top of the printed layer on the substrate, making problems such as wear and breakage less likely to occur. However, by forming a printed layer using the ink or varnish of the electron beam-curable composition of the above embodiment, properties required for food packaging materials, such as excellent adhesion to the substrate and low migration, can be easily obtained.

[0119] In one embodiment, the laminate preferably has a concentration of the (meth)acrylate compound with the largest migration amount of less than 50 ppb in a migration resistance test described later. (Migration Resistance Test) A plastic film such as an OPP film is used as a substrate, and an electron beam curable composition (ink or varnish) is applied to one side of the film at an amount of 2 to 3 g / m. ２ The coating is then printed to form a coating film with a coating amount of 1 kg / dm. The coating film is then irradiated with electron beams using an electron beam irradiator to harden the coating film and form a printed surface. The irradiation conditions may be, for example, an acceleration voltage of 110 kV and an electron beam dose of 30 kGy. The substrate is then superimposed and held so that the printed surface of the substrate and the non-printed surface of another substrate are in contact with each other. More specifically, for example, 1 kg / dm ２ The sheet can be stored for 10 days under environmental conditions of 25°C and 50% humidity with a load of 1000 kJ / s. Thereafter, residual monomers (unreacted (meth)acrylate components) are extracted with ethanol. More specifically, for example, the sheet can be stored for 10 days under the environmental conditions of 25°C and 50% humidity with a load of 100 kJ / s. The remaining monomers (unreacted (meth)acrylate components) are extracted with ethanol ２Residual monomers are extracted from the sample with 50 ml of 95% ethanol at 60° C. for 10 days. The extract is then analyzed using a quadrupole time-of-flight mass spectrometer and a liquid chromatograph to determine the concentration of each (meth)acrylate compound present in the ethanol.

[0120] The laminate of the above embodiment can easily satisfy the requirements for safety, such as low migration, and can therefore be suitably used as a food packaging material.

[0121] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, "parts" in this specification represent parts by mass, and "%" represents % by mass.

[0122] Details of the various measurements carried out in the following examples are as follows.

[0123] (Component Analysis of Rosin Acids) The rosin acids used as raw materials were analyzed by gas chromatography mass spectrometry, and the ratio (%) of each peak area relative to the total rosin acid peak area (100%) was determined. More specifically, the content ratio of conjugated rosin acids contained in the rosin acids that undergo a Diels-Alder addition reaction with an α,β-unsaturated carboxylic acid or its acid anhydride (B) to components other than the conjugated rosin acids was determined from the ratio of the corresponding peak areas.

[0124] (Confirmation of the Progress of the Diels-Alder Addition Reaction and Quantitation of the Produced Addition Reaction Products) The reaction solution of the Diels-Alder addition reaction was analyzed by a gas chromatography mass spectrometer, and the progress of the reaction was confirmed by the decrease in the detection peaks of the rosin acids (a1) and α,β-unsaturated carboxylic acid or its acid anhydride (a2) used as raw materials. The reaction was terminated when no change in the decrease in the detection peaks was observed.

[0125] (Measurement of Weight-Average Molecular Weight) The weight-average molecular weight (Mw) was measured using a gel permeation chromatography (HLC-8320) manufactured by Tosoh Corporation. A calibration curve was prepared using a standard polystyrene sample. Tetrahydrofuran was used as the eluent, and three TSKgel Super HM-M columns (manufactured by Tosoh Corporation) were used. The measurement was carried out under the conditions of a flow rate of 0.6 mL / min, an injection volume of 10 μL, and a column temperature of 40°C.

[0126] 1. Preparation of binder resin 1-1. Preparation of rosin-modified resin A rosin-modified resin was prepared according to the following recipe. The gum rosin used in the recipe contained 80% by mass of a conjugated rosin acid that undergoes a Diels-Alder addition reaction with an α,β-unsaturated carboxylic acid or its acid anhydride (a2), and 20% by mass of a substance other than the conjugated rosin acid.

[0127] (Preparation of Rosin-Modified Resin 1) 52.9 parts of gum rosin, 37.0 parts of phthalic anhydride, 10.0 parts of glycerin, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added to a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and a dehydration condensation reaction was carried out at 230°C for 6 hours to obtain Rosin-Modified Resin 1.

[0128] (Preparation of Rosin-Modified Resin 2) 50.0 parts of gum rosin, 41.9 parts of tetrahydrophthalic anhydride, 8.0 parts of glycerin, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added to a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and a dehydration condensation reaction was carried out at 230°C for 7 hours to obtain Rosin-Modified Resin 2.

[0129] (Preparation of Rosin-Modified Resin 3) 25.0 parts of gum rosin and 15.9 parts of maleic anhydride were placed in a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and heated at 180°C for 1 hour while blowing in nitrogen gas to obtain a reaction mixture. 38 parts of benzoic acid, 5.0 parts of trimethylolpropane, 16.0 parts of pentaerythritol, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added to the reaction mixture, and a dehydration condensation reaction was carried out at 230°C for 9 hours to obtain Rosin-Modified Resin 3.

[0130] (Preparation of Rosin-Modified Resin 4) 27.0 parts of gum rosin and 17.0 parts of maleic anhydride were placed in a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and heated at 180°C for 1 hour while blowing in nitrogen gas to obtain a reaction mixture. To this reaction mixture, 31.9 parts of benzoic acid, 8.0 parts of trimethylolpropane, 16.0 parts of pentaerythritol, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added, and a dehydration condensation reaction was carried out at 230°C for 10 hours to obtain Rosin-Modified Resin 4.

[0131] (Preparation of Rosin-Modified Resin 5) 38.5 parts of gum rosin and 27.0 parts of maleic anhydride were placed in a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and heated at 180°C for 1 hour while blowing in nitrogen gas to obtain a reaction mixture. To this reaction mixture, 11.6 parts of tetrahydrophthalic anhydride, 14.8 parts of glycerin, 8.0 parts of pentaerythritol, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added, and a dehydration condensation reaction was carried out at 230°C for 12 hours to obtain Rosin-Modified Resin 5.

[0132] (Preparation of Rosin-Modified Resin 6) 37.0 parts of gum rosin and 30.0 parts of maleic anhydride were placed in a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, and heated at 180°C for 1 hour while blowing in nitrogen gas to obtain a reaction mixture. 9.9 parts of tetrahydrophthalic anhydride, 15.0 parts of glycerin, 8.0 parts of pentaerythritol, and 0.1 parts of p-toluenesulfonic acid monohydrate as a catalyst were added to this reaction mixture, and a dehydration condensation reaction was carried out at 230°C for 12 hours to obtain Rosin-Modified Resin 6.

[0133] The formulations and weight average molecular weights of rosin-modified resins 1 to 6 are shown in Table 1.

[0134]

[0135] In Table 1, the amounts of each monomer used in preparing the resin (A) are all expressed in parts by mass of the solid content.

[0136] 1-2. Preparation of urethane (meth)acrylate resin A urethane (meth)acrylate resin was prepared according to the following formulation.

[0137] (Preparation of Polyester Polyol 1) 36.2 parts of ethylene glycol and 63.8 parts of adipic acid were placed as raw materials in a four-neck flask equipped with a stirrer, a Dean-Stark tube, a thermometer, and a gas inlet tube, and the mixture was heated with stirring to 220° C. The reaction was carried out while removing condensed water produced as the reaction proceeded from the system, and was terminated when the theoretical amount of dehydration was reached, thereby obtaining Polyester Polyol 1.

[0138] (Preparation of Polyester Polyols 2 to 6) Polyester polyol resins 2 to 6 were prepared in the same manner as in the preparation of Polyester Polyol 1, except that the formulation of Polyester Polyol 1 was changed to the formulations shown in Table 2, respectively.

[0139]

[0140] (Preparation of Urethane (Meth)acrylate Resin 1) Into a four-neck flask equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube, 50.4 parts of Polyester Polyol 1 and 29.3 parts of hexamethylene diisocyanate were placed, and the mixture was reacted with stirring at 100° C. for 3 hours. Next, 20.3 parts of HEA was added, and the mixture was further reacted at 110° C. for 5 hours to obtain Urethane (Meth)acrylate Resin 1.

[0141] (Preparation of Urethane (Meth)acrylate Resins 2 to 6) Urethane (meth)acrylate Resins 2 to 6 were prepared in the same manner as for the preparation of Urethane (meth)acrylate Resin 1, except that the formulation of the urethane (meth)acrylate resin was changed to the formulation shown in Table 3. The weight average molecular weights of Urethane (meth)acrylate Resins 1 to 6 are shown in Table 1. Details of the commercially available products used are as follows: HEA: 2-hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Ltd.)

[0142]

[0143] 1-3. Preparation of Polyester Resin A polyester resin was prepared according to the following recipe. 10 parts of glycerin, 20 parts of ethylene glycol, and 59 parts of phthalic anhydride were placed as raw materials in a four-neck flask equipped with a stirrer, a Dean-Stark tube, a thermometer, and a gas inlet tube, and heated to 220°C with stirring. The reaction was carried out while removing the condensed water produced as the reaction progressed, and was terminated when the theoretical amount of dehydration was reached, yielding Polyester Resin 1 (weight average molecular weight: 10,500, hydroxyl value 119 KOH / g).

[0144] In addition, the following commercially available resins were used: DAP-K (diallyl phthalate resin, weight average molecular weight 25,000, manufactured by Osaka Soda Co., Ltd.) RADPAR AD-032 (non-phthalate allyl resin, weight average molecular weight 32,000, manufactured by Osaka Soda Co., Ltd.)

[0145] 2. Preparation of Varnishes Raw materials were placed in a four-neck flask equipped with a stirrer, a Dean-Stark tube, a thermometer, and a gas inlet tube according to the formulations in Table 4, heated to 100°C with stirring, and stirred and melted at 100°C for 2 hours to obtain varnishes 1 to 15 shown in Table 4. Details of the commercially available products used are as follows: Miramer M600: dipentaerythritol hexaacrylate (weight average molecular weight 578, number of acryloyl groups per molecule: 6, weight average molecular weight per acryloyl group: 96, manufactured by Bigen Specialty Chemical Co., Ltd.)

[0146]

[0147] 3. Preparation of electron beam curable lithographic printing inks and electron beam curable varnishes (Examples 1 to 29, Comparative Examples 1 to 12) (Preparation of electron beam curable lithographic printing inks and electron beam curable varnishes) The raw materials were blended and mixed to obtain the blending ratios shown in Table 5, and milled in a three-roll mill set at 40°C, to obtain the inks and varnishes of Examples 1 to 29 and Comparative Examples 1 to 12.

[0148] The following commercially available materials were used to prepare the inks. <Pigments> FG-7330G: LIONOL BLUE FG-7330G (indigo pigment, manufactured by Toyo Color Co., Ltd.) CR-90-2: TYPAQUE CR-90-2 (titanium oxide, manufactured by Ishihara Sangyo Kaisha, Ltd.) AEROSIL200V (fumed silica, manufactured by Nippon Aerosil Co., Ltd.) Hi-Filler #5000PJ (talc, manufactured by Matsumura Sangyo Co., Ltd.)

[0149] <(Meth)acrylate Compounds> EBECRYL 10551 (amine-modified acrylate, weight average molecular weight: 500, number of acryloyl groups per molecule: 2.5, weight average molecular weight per acryloyl group: 200, manufactured by Daicel-Allnex Corporation) EBECRYL 10553 (amine-modified acrylate, weight average molecular weight: 780, number of acryloyl groups per molecule: 4, weight average molecular weight per acryloyl group: 195, manufactured by Daicel-Allnex Corporation) EBECRYL 80 (amine-modified acrylate, weight average molecular weight: 1,000, number of acryloyl groups per molecule: 4, weight average molecular weight per acryloyl group: 250, manufactured by Daicel-Allnex Corporation) Laromer PO 9139 (amine-modified acrylate, weight-average molecular weight: 5,900, manufactured by BASF)

[0150] EBECRYL 851 (polyester acrylate, weight average molecular weight: 500, number of acryloyl groups per molecule: 2.5, weight average molecular weight per acryloyl group: 200, manufactured by Daicel-Allnex Corporation) EBECRYL 800 (polyester acrylate, weight average molecular weight: 780, number of acryloyl groups per molecule: 4, weight average molecular weight per acryloyl group: 195, manufactured by Daicel-Allnex Corporation) EBECRYL 810 (polyester acrylate, weight average molecular weight: 1,000, number of acryloyl groups per molecule: 4, weight average molecular weight per acryloyl group: 250, manufactured by Daicel-Allnex Corporation) EBECRYL 450 (polyester acrylate, weight average molecular weight: 1,600, number of acryloyl groups per molecule: 6, weight average molecular weight per acryloyl group: 267, manufactured by Daicel Allnex Corporation) UF-3007 (polyester acrylate, weight average molecular weight: 3,600, number of acryloyl groups per molecule: 2.5, weight average molecular weight per acryloyl group: 1440, manufactured by Kyoeisha Chemical Co., Ltd.)

[0151] Miramer M3150 (trimethylolpropane ethylene oxide adduct (15 mol) triacrylate, weight average molecular weight 956, number of acryloyl groups per molecule: 3, weight average molecular weight per acryloyl group: 319, manufactured by MIWON Corporation) Miramer M3160 (trimethylolpropane ethylene oxide adduct (6 mol) triacrylate, weight average molecular weight 560, number of acryloyl groups per molecule: 3, weight average molecular weight per acryloyl group: 187, manufactured by MIWON Corporation) Miramer M3130 (trimethylolpropane EO-modified (3 mol) triacrylate, weight average molecular weight 428, number of acryloyl groups per molecule: 3, weight average molecular weight per acryloyl group: 143, manufactured by MIWON Corporation)

[0152] <Polymerization inhibitor> Polystop 7300P (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, Hakuto Co., Ltd., trade name)

[0153]

[0154]

[0155]

[0156]

[0157] 4. Evaluation of Electron Beam-Curable Planographic Printing Inks and Electron Beam-Curable Varnishes For each of the electron beam-curable planographic printing inks and varnishes prepared in the Examples and Comparative Examples, laminates were produced according to the following method and the following evaluations were carried out.

[0158] (Transportation Vibration Test) A laminating adhesive (TM-321A / TM-321B = 2 / 1 manufactured by Toyo-Morton Co., Ltd.) was applied to a PET film (Emblett PTM, 12 μm) using a bar coater to form a coating film. More specifically, a diluted solution of the adhesive was prepared by diluting it with ethyl acetate so that the active ingredient was 30% by mass. This diluted solution of the adhesive was used, and the coating amount of solids after evaporation of the solvent at room temperature was 2.0 to 2.5 g / m. ２The coating was adjusted to a thickness of 100 μm and applied to form a coating film. After volatilizing the solvent from the coating in a drying oven, it was laminated to aluminum foil (7 μm thick, hereinafter AL) to obtain a PET / AL laminate. Next, a laminating adhesive was applied to the AL foil surface of the obtained laminate in the same manner as above, and the solvent was evaporated. The coated surface was then laminated to an OPA film (Emblem ONM, 15 μm). A laminating adhesive was applied to the OPA film surface of the obtained laminate in the same manner as above, and the solvent was evaporated. The coated surface was then laminated to the corona-treated surface of an unstretched polypropylene film (FHK2, 40 μm thick, manufactured by Futamura Chemical Co., Ltd., hereinafter referred to as "CPP"). The obtained laminate was left for 24 hours in an environment of 35°C and 60% to 80% RT humidity to obtain a laminate having a configuration of PET / adhesive layer / AL / adhesive layer / OPA / adhesive layer / CPP.

[0159] The inks and varnishes of Examples 1 to 27 and Comparative Examples 1 to 12 were applied to the PET film surface of the obtained laminate at a rate of 1 g / m2 using an RI tester (a simple color development device manufactured by Akira Seisakusho Co., Ltd.). ２ The printed coating film was immediately cured using an electron beam irradiator EC250 / 15 / 180L manufactured by Iwasaki Electric Co., Ltd. at an acceleration voltage of 110 kV and an electron beam dose of 30 kGy to obtain a laminate having a configuration of ink layer (cured coating film) / PET / adhesive layer / AL / adhesive layer / OPA / adhesive layer / CPP.

[0160] The resulting laminate was used to prepare pouches measuring 14 cm x 18 cm, which were filled with 150 ml of water. Twenty of these pouches were prepared, placed in cardboard boxes, and subjected to transport vibration tests under conditions of a controlled acceleration of 1 G and a vibration frequency of 6 Hz for 15 minutes in the horizontal direction, 15 minutes in the vertical direction, and 15 minutes in the height direction, and the results were evaluated as follows. An industrially practical level is "3" or higher, with "4" or higher being more preferable.

[0161] (Evaluation criteria for transportation vibration test) 5: No scratches or peeling can be visually confirmed in any of the 20 pouches. 4: Scratches or peeling can be visually confirmed in one of the 20 pouches. 3: Scratches or peeling can be visually confirmed in two of the 20 pouches. 2: Scratches or peeling can be visually confirmed in 3 to 10 of the 20 pouches. 1: Scratches or peeling can be visually confirmed in 11 to 20 of the 20 pouches.

[0162] (Adhesion Test) The electron beam curable lithographic printing inks and varnishes of Examples 1 to 29 and Comparative Examples 1 to 12 were applied to the film at a concentration of 1 g / m using an RI tester (a simple color development device manufactured by Akira Seisakusho Co., Ltd.). ２ The coating was printed so that the coating amount was 100 μg / cm². The coating film after printing was immediately cured using an electron beam irradiator EC250 / 15 / 180L manufactured by Iwasaki Electric Co., Ltd., at an acceleration voltage of 110 kV and an electron beam dose of 30 kGy to obtain a laminate of film / printed layer (cured coating film). Tape adhesion was evaluated using the obtained laminate. For measurement, adhesive tape (cellophane tape (width: 12 mm) manufactured by Nichiban Co., Ltd.) was applied to the printed surface (surface of the printed layer) and quickly peeled off at an angle of 180 degrees, and the area percentage of the coating film remaining on the printed matter (laminate) was evaluated on a 5-point scale according to the following criteria. An industrially practical level is "3" or higher, with "4" or higher being more preferable.

[0163] (Evaluation criteria for adhesion test) 5: The area of ​​the remaining coating film is 90% or more 4: The area of ​​the remaining coating film is 70% or more but less than 90% 3: The area of ​​the remaining coating film is 50% or more but less than 70% 2: The area of ​​the remaining coating film is 25% or more but less than 50% 1: The area of ​​the remaining coating film is less than 25%

[0164] The following films were used in the adhesion study. However, the effect of improving adhesion in the present invention is not limited to these film substrates. OPP: FOR (30 μm) manufactured by Futamura Chemical Co., Ltd. PE: White polyethylene film (50 μm) PET: Emblet PTM (12 μm) manufactured by Unitika Ltd. OPA: Emblem ONM (15 μm) manufactured by Unitika Ltd.

[0165] (Migration Resistance Test) A laminating adhesive (TM-321A / TM-321B = 2 / 1, manufactured by Toyo-Morton Co., Ltd.) was applied to an OPP film (FOR, 30 μm, manufactured by Futamura Chemical Co., Ltd.) using a bar coater to form a coating film. More specifically, a diluted solution of the adhesive was prepared by diluting it with ethyl acetate so that the active ingredient was 30%. This diluted solution of the adhesive was used, and the coating amount of solids after solvent evaporation at room temperature was 2.0 to 2.5 g / m. ２ The coating was adjusted so that the viscosity was adjusted to 100% and then coated to form a coating film. After the solvent in the coating film was evaporated in a drying oven, the coated surface was bonded to the corona-treated surface of an unstretched polypropylene film (FHK2, manufactured by Futamura Chemical Co., Ltd., thickness 40 μm, hereinafter referred to as "CPP"). Next, the film was left for 24 hours in an environment of 35°C and 60% to 80% RT humidity to obtain a laminate having an OPP / adhesive layer / CPP configuration.

[0166] The inks of Examples 1 to 29 and Comparative Examples 1 to 12 were applied to the OPP film surface of the obtained laminate using an RI tester (a simple color development device manufactured by Akira Seisakusho Co., Ltd.) at a rate of 2 to 3 g / m relative to the film. ２ The printed coating was immediately cured using an electron beam irradiator EC250 / 15 / 180L manufactured by Iwasaki Electric Co., Ltd., at an acceleration voltage of 110 kV and an electron beam dose of 30 kGy, to obtain a laminate having a structure of ink layer (cured coating film) / OPP / adhesive layer / CPP. Next, the obtained printed matter was cut into 9 cm x 9 cm pieces to prepare three pieces, which were then stacked so that the printed surface and the non-printed surface were in contact with each other, and the three pieces were then applied with a 1 kg / dm ２ The printed matter in the center of the three sheets was taken out, and the area of ​​the non-printed surface of the printed matter was 0.5 dm². ２The solution was placed in a migration cell so that 50 ml of 95% ethanol was in contact with the ethanol. Subsequently, the residual monomer (unreacted (meth)acrylate component) was extracted at 60°C for 10 days while stirring. The migration cell was completely sealed with equipment, completely preventing loss of the contents and contamination of the contents (extract) with other components during the above process. Next, the extract was analyzed using a quadrupole-time-of-flight mass spectrometer manufactured by Bruker Daltonics and an LC30A series liquid chromatograph manufactured by Shimadzu Corporation, and the concentration of each (meth)acrylate compound was determined as the (meth)acrylate component (A) present in the ethanol. Furthermore, migration resistance was evaluated according to the following criteria. An industrially practical level is "3" or higher, with "4" or higher being more preferable.

[0167] (Evaluation criteria for migration resistance) 5: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound that migrates the most is less than 10 ppb. 4: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound that migrates the most is 10 ppb or more and less than 25 ppb. 3: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound that migrates the most is 25 ppb or more and less than 50 ppb. 2: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound that migrates the most is 50 ppb or more and less than 100 ppb. 1: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound that migrates the most is 100 ppb or more.

[0168] <Evaluation of Printability> Printing tests were conducted using the inks and varnishes obtained in Examples 1 to 29 and Comparative Examples 1 to 12. The printing tests were conducted using a Comexi CI-8 (an offset printing press manufactured by Comexi) on OPP film (FOR (30 μm) manufactured by Futamura Chemical Co., Ltd.). The printing speed was 200 m / min, and the EB irradiation conditions were 110 kV and 30 kGy. Furthermore, tap water containing 3.0% SUNFOUNT S27H (manufactured by SUNCHRMICAL) was used as the dampening solution in the printing tests. In order to compare the printing conditions near the boundary of the range of conditions in which normal printing is possible, printing was conducted with a water dial value 2% higher than the lower limit of the water width. The "lower limit of the water width" refers to the minimum amount of dampening water supplied that allows normal printing, and the "water dial" refers to a dial provided on the printing press for adjusting the amount of dampening water supplied.

[0169] (Film Strength Test) The surfaces of the printed materials obtained by printing the inks of Examples 1 to 29 and Comparative Examples 1 to 12 were rubbed with a cotton swab immersed in 99.5% ethanol solution at a rate of one stroke per second, and the number of strokes required until the surface of the cured film was scraped off was evaluated on a 5-point scale according to the following criteria: An industrially practical level is "3" or higher, with "4" or higher being more preferable. 5: 100 strokes or more 4: 50 to less than 100 strokes 3: 30 to less than 50 strokes 2: 10 to less than 30 strokes 1: Less than 10 strokes

[0170] (High-speed printing suitability test) For the inks obtained in Examples 1 to 29 and Comparative Examples 1 to 12, the printing speed was adjusted to a standard density at 100 m / min under conditions other than the printing speed being fixed, and then the printing speed was increased to 200 m / min. 500 m of printing was carried out, and the density fluctuation when the ink was printed was evaluated on a 5-point scale according to the following criteria. A practically acceptable level is "3" or higher, with "4" or higher being more preferable. 5: Density fluctuation is less than ±5% 4: Density fluctuation is ±5% or more but less than 10% 3: Density fluctuation is ±10% or more but less than 15% 2: Density fluctuation is ±15% or more but less than 20% 1: Density fluctuation is ±20% or more

[0171] (Scumming Resistance Test) In the above printing test, as the printing length increased, ink gradually adhered to the roller supplying dampening water. As the amount of dampening water supplied decreased, ink was more likely to be applied to the non-image areas (areas where ink should not be applied) where the image was being formed on the printed material. These results indicate that as the printing length increased, scumming was more likely to occur on the printed material. For the reasons mentioned above, the water dial was set to a value 2% higher than the lower limit of the water width, and the printed material was visually inspected and evaluated on a 5-point scale according to the following criteria. A practical level is "3" or higher, with "4" or higher being more preferable. 5: No scumming was observed, especially on the film, in 8,000 m of printing. 4: Scumming occurred in non-image areas in printing from 6,000 m to less than 8,000 m. 3: Scumming occurred in non-image areas in printing from 4,000 m to less than 6,000 m. 2: When printing 2,000 m or more but less than 4,000 m, scumming occurs in non-image areas. 1: When printing less than 2,000 m, scumming occurs in non-image areas.

[0172]

[0173] As described above, the present invention has provided an electron beam-curable composition that imparts excellent adhesion to various film substrates, imparts low migration properties and transport durability, which are important in the packaging market, and is excellent in health and environmental safety, as well as a laminate using the electron beam-curable composition. Furthermore, the present invention has provided an electron beam-curable composition that exhibits excellent printability when used as an ink.

Claims

1. 1. An electron beam curable composition comprising: a resin (A) having a weight average molecular weight of 5,000 to 50,000; a (meth)acrylate compound (B) having a weight average molecular weight of 700 to 3,000 and a weight average molecular weight per (meth)acryloyl group of 100 to 300; and a pigment (C), wherein the content of the (meth)acrylate compound having a weight average molecular weight of less than 500 is 25 mass% or less based on the total mass of the composition.

2. 2. The electron beam curable composition according to claim 1, wherein a ratio of a content (% by mass) of the (meth)acrylate compound (B) in the total mass of the composition to a content (% by mass) of the resin (A) in the total mass of the composition is 0.5 to 8.

0.

3. 2. The electron beam curable composition according to claim 1, wherein the resin (A) comprises at least one resin selected from the group consisting of a rosin-modified resin, a diallyl phthalate resin, a polyester resin, and a urethane (meth)acrylate resin.

4. The electron beam curable composition according to claim 1 , wherein the (meth)acrylate compound (B) comprises an amine-modified (meth)acrylate.

5. The electron beam curable composition according to claim 1 , wherein the (meth)acrylate compound (B) comprises a polyester (meth)acrylate.

6. 2. The electron beam curable composition according to claim 1, wherein a total content of the resin (A), the (meth)acrylate compound (B), and the pigment (C) is 60 to 90 mass% with respect to a total mass of the composition.

7. The electron beam curable composition according to claim 1 , which is substantially free of a photopolymerization initiator.

8. The electron beam curable composition according to claim 1 , which is substantially free of organic solvents.

9. 2. The electron beam curable composition according to claim 1, which is substantially free of polytetrafluoroethylene wax.

10. A laminate comprising a substrate and a cured product of the electron beam curable composition according to any one of claims 1 to 9.

11. The laminate according to claim 10, wherein the substrate is a film or paper.

12. 11. A method for producing the laminate according to claim 10, comprising: applying the electron beam curable composition according to any one of claims 1 to 9 onto a substrate to form a coating film; and irradiating the coating film with an electron beam under conditions of an acceleration voltage of 40 to 120 kV and an exposure dose of 10 to 60 kGy.