JP7700970B2 - Electron beam curable composition and laminate - Google Patents

Description

Embodiments of the present invention relate to electron beam curable compositions and laminates.

In recent years, the use of curing technology using active energy rays has expanded in the printing industry. Curing technology using active energy rays makes it possible to shorten process times through instant drying, reduce the environmental impact and improve work safety by being non-volatile (non-VOC), and achieve strong coating film properties through crosslinking reactions.

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

In particular, when the packaging material is used for food packaging, it is essential to use an active energy ray curable composition that can suppress migration in order 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 the safety of food packaging. In particular, Swiss Ordinance RS817.023.21 Annex10 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 amount (SML) for each raw material. The regulation level in the Swiss Ordinance is very strict, but due to the increasing safety consciousness of consumers, the regulation level has become an important indicator as a global standard for food packaging materials in recent years.

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

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

Furthermore, in order to meet the diversification and sophistication of consumer needs in recent years, the laminates that make up the packaging materials for packages have become more diverse and complex. For this reason, there is a demand for active energy ray-curable compositions that have good adhesion to various substrate configurations and can form strong coatings.

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 there is a trade-off between film strength and adhesion.

A related problem is that with packaging materials for packages that have a printed surface after being printed with active energy ray-curable ink, the printed surface of the packaging material can become scratched or peeled off due to vibrations and friction that occur when transporting the packaging materials in trucks, etc., and a solution to this problem is desired.

In addition, 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 is narrowing. In particular, active energy ray-curable compositions that do not contain persistent organic pollutants such as tetrafluoroethylene and do not contain photopolymerization initiators from the standpoint of health and safety are desired.

On the other hand, various printing methods are used for printing active energy ray-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 printing areas and water (dampening water) in the non-printing areas, and waterless lithographic printing, which uses a silicone layer in the non-printing areas to form an image by the repulsion of the ink in the printing areas. Of these, wet lithographic printing, which has good workability, is preferably used.

Recently, there has been a strong demand in printing sites for shorter delivery times, labor and energy savings, and faster printing speeds, with the aim of improving production efficiency and reducing costs. For this reason, there is a demand for printing inks that can produce high-quality prints stably over long periods of time at high speeds without any problems. In particular, it is difficult for active energy ray-curable compositions for film substrates to ensure the necessary viscoelasticity and emulsification performance when made into printing inks. As a result, there are issues such as unstable concentration during high-speed printing and the tendency for smudges to occur during printing, and a solution to these issues is desired.

Under these circumstances, inks and varnishes, which are active energy ray-curable compositions, have been considered.

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

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 has insufficient resistance to scratches and peeling caused by vibration and friction during transportation.

Patent Document 3 discloses an electron beam curable composition comprising, 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 has a configuration developed for use as a primer. Therefore, particularly when used in wet lithographic printing, the emulsification balance with the dampening water is poor, and since the binder resin needs to be made into a low molecular weight resin, the viscoelasticity required for the ink cannot be obtained, making it difficult to obtain high-quality printed matter stably over a long period of time.

Patent Document 4 discloses an active energy ray-curable resin composition comprising, as essential components, a urethane (meth)acrylate resin having a specific weight average molecular weight and a (meth)acrylate compound having two types of (meth)acryloyl groups, one to two functional groups and one with three or more functional groups. 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 the curability and migration properties during high-speed printing may be deteriorated. In addition, there is a tendency for the stability on the press and the stability during emulsification during water-based lithographic printing to deteriorate.

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

One embodiment of the present invention provides an electron beam curable composition that has safety, such as low migration properties, and can be used as a packaging material for various packages, and can form a film that has both excellent adhesion to a film substrate and 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.

As a result of extensive research, the inventors have discovered that the above problems can be solved by using the electron beam curable composition described below, and have completed the present invention. The following describes an embodiment of the present invention. However, the present invention is not limited to the following embodiment, and includes various embodiments.

<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).

<2> An electron beam curable composition described in <1> above, in which 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.

<3> An electron beam curable composition described in <1> or <2> above, wherein the resin (A) contains one or more resins selected from the group consisting of rosin-modified resins and urethane (meth)acrylate resins.

<4> An electron beam curable composition described in any one of <1> to <3> above, wherein the (meth)acrylate compound (B) contains an amine-modified (meth)acrylate.

<5> An electron beam curable composition described in any one of <1> to <4> above, wherein the (meth)acrylate compound (B) contains a polyester (meth)acrylate.

<6> An electron beam curable composition described in any one of <1> to <5> above, 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.

<7> An electron beam curable composition described in any one of <1> to <6> above, which is substantially free of a photopolymerization initiator.

<8> An electron beam curable composition described in any one of <1> to <7> above, which is substantially free of organic solvents.

<9> An electron beam curable composition described in any one of <1> to <8> above, which is substantially free of polytetrafluoroethylene wax.

<9> A laminate having a cured product of an electron beam curable composition described in any one of <1> to <9> above on a substrate.

<10> A laminate described in <9> above, wherein the substrate is a film or paper.

<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 under conditions of 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.

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 properties, and can be used as a packaging material for various packages, and that can form a coating film that combines excellent adhesion to a film substrate and film strength, thereby reducing problems such as rubbing or peeling during transportation and having good printability. It is also possible to provide a laminate using the electron beam curable composition of the above embodiment.

Hereinafter, an embodiment of the present invention will be described in detail. However, the present invention is not limited to the embodiment described below, and various modifications are possible without departing from the spirit of the present invention.

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 in between. However, the π-electron conjugated system contained in aromatic compounds is excluded from the conjugated double bond.
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.

<Resin (A)>
The resin (A) in the electron beam curable composition of this embodiment is a resin having a weight average molecular weight of 5,000 to 50,000. The type of resin is not particularly limited as long as the weight average molecular weight is 5,000 to 50,000, and any known resin can be used, but a resin that has good compatibility with and is soluble in a (meth)acrylate compound is preferred.
When the weight average molecular weight of the resin is adjusted to 5,000 or more, the required ink viscoelasticity can be easily obtained when the electron beam curable composition is made into ink, and the required emulsification performance can be easily obtained when used in wet lithographic printing. Also, when the weight average molecular weight is adjusted to 50,000 or less, good adhesion to the film can be easily obtained.
In one embodiment, the weight average molecular weight of the resin (A) is preferably 10,000 to 25,000.

Resin (A) may have a weight average molecular weight within the above range, and may or may not contain a (meth)acryloyl group within the molecule.

Specific examples of resin (A) include diallyl phthalate resin, rosin-modified resin, polyester resin, epoxy resin, urethane (meth)acrylate resin, polyester (meth)acrylate resin, styrene-acrylic polymerized resin, petroleum resin, allyl resin, etc. In one embodiment, resin (A) may include 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, allyl resins other than diallyl phthalate resin, such as non-phthalate allyl resin, can also be used as the allyl resin. That is, in such an embodiment, resin (A) may include 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.

In one embodiment, from the viewpoints of printability, film strength, and adhesion, it is preferable that the resin (A) contains at least one selected from the group consisting of rosin-modified resins and urethane (meth)acrylate resins.

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

In one embodiment, the rosin-modified resin preferably comprises a reaction product of raw material components including rosins, polybasic acids, and polyols. 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.

In an embodiment of the present invention, the rosins refer to monobasic acids having a cyclic diterpene skeleton, and include rosin acid, disproportionated rosin acid, hydrogenated rosin acid, and alkali metal salts of the above compounds.
Specific examples of rosins include abietic acid, which has a conjugated double bond, and its conjugated compounds, 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.

Polybasic acids include carboxylic acids having two or more carboxyl groups in one molecule, and their anhydrides.

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, alkenylsuccinic acids such as dodecenylsuccinic acid and 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.

Polyols include compounds that have two or more hydroxyl groups in one molecule, such as dihydric alcohols and trihydric or higher alcohols.

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, and hydrogenated hydroquinone.
Further examples include polyether polyols such as polyethylene glycol (n=2 to 20), polypropylene glycol (n=2 to 20), and polytetramethylene glycol (n=2 to 20), and polyester polyols.

Furthermore, 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, tripentaerythritol, etc.

<Urethane (meth)acrylate resin>
In an 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 formed by reacting an isocyanate group with a hydroxyl group.

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 in which the isocyanate group is in excess.

In one embodiment, from the viewpoint of easily improving the coating film properties, the urethane (meth)acrylate resin is preferably a compound containing a polyester segment and/or a compound containing a polyether segment. Such a compound is 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.

Below, we will explain some representative compounds that can be used as raw materials for urethane (meth)acrylate resins.

The polyisocyanate is not particularly limited, but may be 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 the isocyanate include 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, it is preferable that the diisocyanate is bifunctional.

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.

Polyols include glycols, polyether polyols, and polyester polyols.

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.

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 in which alkylene oxides such as ethylene oxide are added to bisphenols such as bisphenol A and bisphenol F can also be used.

Examples of polyester polyols include polyester polyols that are the result of a condensation reaction between a polyhydric alcohol component and a polybasic acid component.

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.

Examples of trihydric or higher polyhydric alcohols include, but are not limited to, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerin, ditrimethylolpropane, sorbitan, sorbitol, dipentaerythritol, inositol, and tripentaerythritol.

The polybasic acid is not particularly limited, and may be either an aliphatic or alicyclic acid.
Examples of the aliphatic polybasic acids 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; and examples of the aromatic polybasic acids 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.
Examples of 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.

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

Here, the above-mentioned polyols can be used without any particular restrictions. They may be used alone or in combination of two or more types according to 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.

<(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 properties, film strength, and adhesion is achieved.

In one embodiment, the (meth)acrylate compound (B) may be suitably used if it has 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 selected from the group consisting of amine-modified (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, urethane (meth)acrylate, silicone (meth)acrylate, epoxy (meth)acrylate, and epoxidized vegetable oil (meth)acrylate may be used. In one embodiment, the (meth)acrylate compound (B) preferably contains an amine-modified (meth)acrylate and/or a polyester (meth)acrylate.

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

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

Here, 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.

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. When the content is within this range, the surface curability, film strength, and background smearing during water-based lithographic printing are all good.

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

In one embodiment of the present invention, polyester (meth)acrylate is a (meth)acrylate compound having a polyester structure in the molecule (except when having an amino group).

In one embodiment, it is desirable for the polyester (meth)acrylate to have 3 to 10 acryloyl groups in the molecule.

In one embodiment, it is desirable to contain polyester (meth)acrylate in an amount of 10 to 50% by mass based on the total mass of the electron beam curable composition. A content of 10 to 50% by mass results in good adhesion, viscoelasticity, and emulsifiability during water-based lithographic printing.

In one embodiment of the present invention, the polyester (meth)acrylate is, for example, EBECRYL manufactured by DAICEL-ALNEX. Examples of the acryloyl groups 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).

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 above-mentioned amine-modified (meth)acrylate and the above-mentioned polyester acrylate.

In one embodiment, polyether (meth)acrylate, urethane (meth)acrylate, silicone (meth)acrylate, epoxy (meth)acrylate, and epoxidized vegetable oil (meth)acrylate can be used as the (meth)acrylate compound (B). Known materials can be used as long as the weight average molecular weight is 700 to 3,000 and the weight average molecular weight per (meth)acryloyl group is 100 to 300. Modified products obtained by adding various modifications to these polyether (meth)acrylate, urethane (meth)acrylate, silicone (meth)acrylate, epoxy (meth)acrylate, and epoxidized vegetable oil (meth)acrylate can also be used.

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 water-based lithographic printing ink.

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 and pigments having other colors. Colored pigments may be either inorganic pigments or organic pigments. By using organic pigments, it is possible to prepare white inks and colored inks having other colors.

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

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 arylide, acetoacetate arylide, and pyrazolone, insoluble azo pigments such as β-naphthol, β-oxynaphthoic acid arylide, acetoacetate arylide monoazo, acetoacetate arylide disazo, and pyrazolone, copper phthalocyanine blue, halogenated (chlorinated or brominated) azo pigments, and the like. ) 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 (pyranthrone, anthanthrone, indanthrone, anthrapyrimidine, flavanthrone, thioindigo, anthraquinones, perinones, perylenes, etc.), isoindolinones, metal complexes, and quinophthalones.

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

In one embodiment, the content of the colored pigment is preferably 2 to 30 mass %, more preferably 5 to 25 mass %, of the total mass of the electron beam curable composition in the case of a color ink. Also, 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 in the case of a white ink. Also, 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 colored pigment.

In one embodiment of the present invention, the extender pigment means a pigment that does not have coloring power, and is distinguished from the colored pigments described above. In an embodiment of the present invention, specific examples of the extender pigment 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.

In one embodiment, when the electron beam curable composition is used as a color ink or a white ink (which may be collectively referred to as ink), the content of the extender pigment is preferably adjusted according to the purpose. For example, for the purpose of improving the fluidity and misting resistance of the ink, it is preferable to use 5 mass % or less of the extender pigment based on the total mass of the electron beam curable composition. In one embodiment, the extender pigment does not need to be used when preparing the ink.
On the other hand, when the electron beam curable composition is used as a transparent ink (varnish), the content of the extender pigment is preferably adjusted depending on the application. In one embodiment, the extender pigment is preferably used in an amount of 30 mass% or less based on the total mass of the electron beam curable composition (varnish). In an embodiment of the 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%.

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 water-based lithographic printing can be easily obtained.

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, 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, more preferably 75 to 85% by mass. When the electron beam curable composition of the above embodiment is used as a varnish and medium, the total content of (A), (B) and (C) is preferably 60 to 80% by mass, more preferably 65 to 75% by mass.

In the above embodiment, it is preferable to include a (meth)acrylate compound (hereinafter referred to as "other (meth)acrylate compound") different from the above (A) and (meth)acrylate compound (B) as a component other than the above (A), (B), and (C). In the above embodiment, the content of the above 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, it is preferable that the content is 25 mass% or less, as described later.

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 kinds.
In the above embodiment, the other (meth)acrylate compound preferably has a weight average molecular weight of 500 or more and is composed of a tri- or higher functional (meth)acrylate compound, from the viewpoints of curability and low migration.

(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 be produced by using an electron beam curable varnish containing the resin (A) described later.

The electron beam curable varnish can be prepared using resin (A) and a (meth)acrylate compound. Although not particularly limited, the electron beam curable varnish preferably contains 10 to 80% by mass of resin (A) and 20 to 90% by 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% by mass of resin (A) and 30 to 80% by mass of the (meth)acrylate compound.

In the above embodiment of the electron beam curable varnish, the (meth)acrylate compound may be any compound capable of adjusting the viscosity of the varnish to a desired range, and both the (meth)acrylate compound (B) and other (i.e., different from the (meth)acrylate compound (B)) (meth)acrylate compounds can be used. In one embodiment, the electron beam curable varnish may be prepared using the resin (A) and the (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 and mixing the (meth)acrylate compound (B) and the pigment (C) to the above varnish. The amount of the varnish to be blended is preferably adjusted so that the ratio (B/A) of the contents of the resin (A) and the (meth)acrylate compound (B) in the electron beam curable composition is within a predetermined range, taking into account the content of the resin (A) in the varnish.

In one embodiment, the (meth)acrylate compounds other than the resin (A) and the (meth)acrylate compound (B) used in 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 in order to ensure low migration. The weight average molecular weight of the above (meth)acrylate compound may be more preferably 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.

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 above content may 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 be within the above range, it becomes easier to ensure low migration properties.

Although not particularly limited, specific examples of the (meth)acrylate compound having a weight average molecular weight of less than 500 are as follows.
Examples of monofunctional (meth)acrylate compounds include 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, β-carboxyethyl (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, and 3,3,5-trimethylcyclohexanol (meth). ) 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, acryloyl morpholine, N-vinyl carbazole, 1-vinylimidazole, N-vinyl-2-pyrrolidone, N-vinyl caprolactam, N-vinyl formamide, and the like.

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, hydrochloric acid, Examples of the di(meth)acrylate include xypivalic acid neopentyl glycol 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, dimethylol-tricyclodecane di(meth)acrylate, dicyclopentanyl di(meth)acrylate, and tris(2-hydroxyethyl)isocyanurate di(meth)acrylate.

Examples of trifunctional or higher (meth)acrylate compounds 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, pentaerythritol tetraacrylate, etc.

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 (meth)acrylate compound, and it is more preferable to use a trifunctional or higher (meth)acrylate compound.

The electron beam curable varnish of the above embodiment may contain, in addition to the above components, a polymerization inhibitor, which will be described later. In such an embodiment, the polymerization inhibitor can be added and used in a conventional manner. When a polymerization inhibitor is added to the above varnish, the amount of the polymerization inhibitor is preferably 3 mass % or less, based on the total mass of the electron beam curable varnish, and more preferably in the range of 0.01 to 1 mass %.

In an embodiment of the present invention, the electron beam curable varnish can be produced by mixing the above components under temperature conditions between room temperature and 160 ° C. For example, it can be produced by mixing a 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 type allyl resin not containing a phthalate structure, 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 under a temperature condition of 100 ° C. can be preferably used.

(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, the amount of the polymerization inhibitor 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 composition, in order not to inhibit the curability.

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, di-t-butyl-7-phenylquinone methide, etc.

In particular, compounds having two hydrocarbon groups each at the 2-position and the 6-position on the piperidine ring (total of four) are preferred. More specifically, it is preferred 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 machine can be inhibited, and excellent storage stability can be easily provided. The above compounds are also available as commercially available products. For example, there is a product name "Polystop 7300P" (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) manufactured by Hakuto Co., Ltd.

(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 blending amount within a range that does not inhibit the effects of other components. The blending amount of various additives is preferably 5 mass% or less based on the total mass of the electron beam curable composition.

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, restrictions are being put in place, as exemplified by the Stockholm Convention on Persistent Organic Pollutants (POPs Convention) that came into force in May 2004. Polytetrafluoroethylene wax is used as an anti-friction agent for printing inks, but may contain persistent organic pollutants such as PFAS. For this reason, it is preferable that the electron beam curable composition, which is one embodiment of the present invention, is substantially free of polytetrafluoroethylene wax.

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 cases where the component is contained in trace amounts in each raw material, contamination during the composition manufacturing process, and the print production process.

In one embodiment of the present invention, the electron beam curable composition is substantially free of organic solvents. There is concern that organic solvents used as viscosity modifiers in printing inks may contain MOSH/MOAH, which are persistent organic pollutants. In addition, the absence of volatile components (Non-VOC) is expected to reduce the environmental load 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.

In one embodiment of the present invention, the electron beam curable composition is substantially free of a photopolymerization initiator. The photopolymerization initiator is expected to have the effect of expressing and improving the curability of the active energy beam curable composition. On the other hand, in the packaging market, particularly in food packaging materials, toiletry packaging materials, medical packaging materials, and the like, there is a concern that the safety and quality may be reduced due to migration of the photopolymerization initiator components. 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.

In one embodiment of the present invention, from the standpoint of carbon neutrality, it is preferable to use biomass-derived raw materials that utilize renewable resources such as plants as the various raw materials used in the electron beam curable composition.

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, kneading, 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, and 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 above-mentioned resin (A).

<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. 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 printing the electron beam curable varnish on a printed material on which ink has been printed on the substrate to form a coating film, and curing this coating film with an electron beam.

In the above embodiment, the substrate that can be used is preferably a film-like substrate, for example, a polyolefin substrate such as polyethylene or polypropylene, a polyester substrate such as polyethylene terephthalate or polylactic acid, a polycarbonate substrate, a polystyrene-based substrate such as polystyrene, AS resin or ABS resin, a nylon substrate, a polyamide substrate, a polyvinyl chloride substrate, a polyvinylidene chloride substrate, a cellophane substrate, a paper substrate, an aluminum substrate, or a film-like substrate made of a composite material thereof.
In addition, as the substrate, a deposition substrate in which an inorganic compound such as silica, alumina, or aluminum is deposited on a polyethylene terephthalate substrate or a nylon substrate can also be used, and the deposition surface may be further coated with polyvinyl alcohol or the like.
The substrate is preferably subjected to an easy-adhesion treatment on the surface to be printed (the surface in contact with the printing layer). Examples of the easy-adhesion treatment include corona discharge treatment, ultraviolet/ozone treatment, plasma treatment, oxygen plasma treatment, primer treatment, etc. In addition, when sufficient adhesion cannot be obtained in a polyethylene terephthalate substrate, an acrylic coating treatment, a polyester treatment, a polyvinylidene chloride treatment, etc. may be performed.

A paper substrate may be used as the substrate. The paper substrate may be ordinary paper or cardboard. The thickness of the paper substrate is not particularly specified, but for example, a substrate having a thickness of 0.2 mm to 1.0 mm and a thickness of 20 to 150 g/ ^m2 may be used, and the printed surface may be easily adhesively treated. The paper substrate may have a surface that is vapor-deposited with a metal such as aluminum for the purpose of imparting design. In addition, the surface may be coated with an acrylic resin, a urethane resin, a polyester resin, a polyolefin resin, or other resin, and may further be subjected to a surface treatment such as a corona treatment. For example, coated paper and art paper may be used.

In one embodiment of the present invention, the printing method of the electron beam curable composition is not particularly limited, and known methods can be used. When the electron beam curable composition is an ink, specifically, wet offset printing (normal lithographic printing using dampening water), waterless offset printing (lithographic printing without dampening water), resin letterpress printing, screen printing, etc. are used. Of these, it is preferable to use offset printing, and it is more preferable to use wet offset printing.

Similarly, when the electron beam curable composition is a varnish, suitable applications include wet offset printing, waterless offset printing, resin letterpress printing, and screen printing. In addition, by adjusting the viscoelasticity, it is possible to select various printing methods such as flexographic printing, gravure printing, and inkjet printing, as well as coating with various coaters.

In one embodiment, the electron beam curable composition is printed by various printing methods (after a coating of the composition is formed), and then the coating is cured through an electron beam irradiator to form a printed layer. It is preferable to use electron beams for curing, taking into consideration 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 preferable to irradiate 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. When the exposure dose is 10 to 60 kGy, sufficient film strength is obtained, and problems due to damage to the film, such as a decrease in film strength, odor, and yellowing, can be suppressed.

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 printed materials, and metal printed materials (fine art printed materials, printed materials for beverage cans, printed materials for canned foods, 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).

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 the coating film. In the above embodiment, the coating film is preferably cured by 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. 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 a rosin-modified resin, a urethane (meth)acrylate resin, a polyester resin, and a diallyl phthalate resin, and the (meth)acrylate compound (B) comprises one or more compounds selected from the group consisting of an amine-modified (meth)acrylate, and a polyester (meth)acrylate.

In one embodiment, the laminate may have a structure for use as a food packaging material. 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 base film, and a metal foil, various films, a sealant layer, or the like, via an adhesive layer, on the other side of the film. 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.

In a surface-printed laminate, the outermost layer of the food packaging material (package) is the printed layer. 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, defects such as rubbing and damage of the package due to vibration and friction during transportation can be easily improved. In this way, the benefits of improving the film strength are significant in a surface-printed laminate. However, the laminate is not limited to a surface-printed form, and may be a reverse-printed form. In a reverse-printed laminate, since it has a structure in which a film or the like is further laminated on the printed layer on the substrate, defects such as rubbing and damage are unlikely to occur. However, by forming a printed layer using the ink or varnish of the electron beam curable composition of the above embodiment, properties such as excellent adhesion to the substrate and low migration, which are required for food packaging materials, can be easily obtained.

In one embodiment, the laminate preferably has a concentration of the (meth)acrylate compound that migrates the most in a migration resistance test described later, which is less than 50 ppb.
(Migration resistance test)
A plastic film such as an OPP film is used as the substrate, and an electron beam curable composition (ink or varnish) is printed on one side of the film in an amount of 2 to 3 g/ ^m2 to form a coating film. An electron beam irradiator is used to irradiate the coating film with electron beams 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 stacked and held so that the printed surface of the substrate and the non-printed surface of the other substrate are in contact with each other. More specifically, the substrate can be held for 10 days at 25°C and 50% humidity with a load of 1 kg/dm2.
Thereafter, the residual monomer (unreacted (meth)acrylate component) is extracted with ethanol. More specifically, for example, the residual monomer is extracted with 50 ml of 95% ethanol for an area of 0.5 ^dm2 of the non-printed surface at 60° C. for 10 days.
Next, the extract is analyzed using a quadrupole time-of-flight mass spectrometer and a liquid chromatograph to determine the concentration of each of the (meth)acrylate compounds present in the ethanol.

The laminate of the above embodiment can easily meet safety requirements such as low migration, making it suitable for use as a food packaging material.

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

Details of the various measurements performed in the following examples are as follows:

(Component analysis of rosin acids)
The rosin acids used as raw materials were analyzed by gas chromatography mass spectrometry to determine the ratio (%) of each peak area relative to the total rosin acid peak area of 100%. 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 anhydride thereof (B) to other than the conjugated rosin acids was determined from the ratio of the corresponding peak areas.

(Confirmation of the progress of the Diels-Alder addition reaction and quantification of the above-mentioned addition reaction product)
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 was observed in the decrease in the detection peaks.

(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 performed 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.

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 had a conjugated rosin acid content of 80% by mass that undergoes a Diels-Alder addition reaction with an α,β-unsaturated carboxylic acid or an acid anhydride thereof (a2), and a content of substances other than the conjugated rosin acid of 20% by mass.

(Preparation of Rosin Modified Resin 1)
To a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, 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, and a dehydration condensation reaction was carried out at 230° C. for 6 hours, thereby obtaining rosin modified resin 1.

(Preparation of Rosin Modified Resin 2)
To a four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer, 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, and a dehydration condensation reaction was carried out at 230° C. for 7 hours, thereby obtaining rosin modified resin 2.

(Preparation of Rosin Modified Resin 3)
A four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer was charged with 25.0 parts of gum rosin and 15.9 parts of maleic anhydride, and heated at 180° C. for 1 hour while blowing in nitrogen gas to obtain a reaction mixture. To the 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, and a dehydration condensation reaction was carried out at 230° C. for 9 hours to obtain rosin-modified resin 3.

(Preparation of Rosin Modified Resin 4)
A four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer was charged with 27.0 parts of gum rosin and 17.0 parts of maleic anhydride, 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.

(Preparation of Rosin Modified Resin 5)
A four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer was charged with 38.5 parts of gum rosin and 27.0 parts of maleic anhydride, 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.

(Preparation of Rosin Modified Resin 6)
A four-neck flask equipped with a stirrer, a reflux condenser with a water separator, and a thermometer was charged with 37.0 parts of gum rosin and 30.0 parts of maleic anhydride, and heated at 180° C. for 1 hour while blowing in nitrogen gas to obtain a reaction mixture. To this 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, and a dehydration condensation reaction was carried out at 230° C. for 12 hours to obtain a rosin-modified resin 6.

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

In Table 1, the amounts of each monomer used in preparing resin (A) are all parts by mass of solids.

1-2. Preparation of urethane (meth)acrylate resin According to the recipe shown below, a urethane (meth)acrylate resin was prepared.

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

(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.

(Preparation of urethane (meth)acrylate resin 1)
Into a four-neck flask equipped with a stirrer, a cooler, a thermometer, and a gas inlet tube, 50.4 parts of polyester polyol 1 and 29.3 parts of hexamethylene diisocyanate were placed and reacted with stirring for 3 hours at 100° C. Then, 20.3 parts of HEA was placed and further reacted for 5 hours at 110° C. to obtain urethane (meth)acrylate resin 1.

(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 Co., Ltd.)

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

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.)

2. Preparation of Varnish 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 formulation 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.)

3. Preparation of electron beam curable lithographic printing ink and electron beam curable varnish (Examples 1 to 29, Comparative Examples 1 to 12)
(Preparation of electron beam curable lithographic printing ink and electron beam curable varnish)
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.

In addition, 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: Tipaque 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.)

<(Meth)acrylate Compound>
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)

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.)

Miramer M3150 (trimethylolpropane ethylene oxide adduct (15 moles) 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 moles) 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 moles) 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)

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

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.

(Transportation vibration test)
A laminating adhesive (TM-321A/TM-321B=2/1, manufactured by Toyo-Morton Co., Ltd.) was applied onto a PET film (Emblett PTM, 12 μm) using a bar coater to form a coating film. More specifically, a diluted solution of the above adhesive was prepared by diluting it with ethyl acetate so that the active ingredient was 30 mass %. This diluted solution of the adhesive was used and applied at room temperature so that the solid coating amount after solvent evaporation was adjusted to 2.0 to 2.5 g/m ² to form a coating film. After the solvent was evaporated from the coating film in a drying oven, it was laminated with aluminum foil (thickness 7 μm, hereinafter referred to as AL) to obtain a PET/AL laminate.
Next, the laminate adhesive was applied to the AL foil surface of the obtained laminate in the same manner as above, the solvent was evaporated, and the applied surface was bonded to an OPA film (EMBLEM ONM, 15 μm). The laminate adhesive was applied to the OPA film surface of the obtained laminate in the same manner as above, the solvent was evaporated, and the applied surface was bonded to the corona-treated surface of an unstretched polypropylene film (FHK2, thickness 40 μm, 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% RT to 80% RT humidity to obtain a laminate having a structure of PET/adhesive layer/AL/adhesive layer/OPA/adhesive layer/CPP.

On the PET film surface of the obtained laminate, the inks and varnishes of Examples 1 to 27 and Comparative Examples 1 to 12 were printed on the film in an amount of 1 g/ ^m2 using an RI tester (a simple color development device manufactured by Akebono Seisakusho Co., Ltd.) to form a coating film. 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 having a configuration of ink layer (cured coating film)/PET/adhesive layer/AL/adhesive layer/OPA/adhesive layer/CPP.

The obtained laminate was used to make pouches measuring 14 cm x 18 cm, which were filled with 150 ml of water. 20 of these pouches were made and placed in cardboard boxes. Transport vibration tests were carried out for 15 minutes in the horizontal direction, 15 minutes in the vertical direction, and 15 minutes in the height direction under conditions of a controlled acceleration of 1 G and a vibration frequency of 6 Hz, and the results were evaluated as follows. The industrially practical level is "3" or higher, with "4" or higher being more preferable.

(Evaluation criteria for transportation vibration test)
5: No scratches or peeling were visually observed in any of the 20 pouches.
4: One out of 20 pouches had visible scratches or peeling.
3: Scratches or peeling were visually confirmed in 2 of 20 pouches.
2: Scratches or peeling are visually confirmed in 3 to 10 of 20 pouches.
1: Scratches or peeling are visually confirmed in 11 to 20 of 20 pouches.

(Adhesion test)
The electron beam curable lithographic printing inks and varnishes of Examples 1 to 29 and Comparative Examples 1 to 12 were printed onto the film using an RI tester (a simple color development device manufactured by Akebono Seisakusho Co., Ltd.) to give a coating amount of 1 g/ ^m2 . 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).
The obtained laminate was used to evaluate tape adhesion. For the measurement, an 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) side 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.

(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 and less than 90%. 3: The area of the remaining coating film is 50% or more and less than 70%. 2: The area of the remaining coating film is 25% or more and less than 50%. 1: The area of the remaining coating film is less than 25%.

The films shown below 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.

(Migration resistance test)
A laminating adhesive (TM-321A/TM-321B=2/1, manufactured by Toyo-Morton Co., Ltd.) was applied onto an OPP film (FOR, manufactured by Futamura Chemical Co., Ltd., 30 μm) using a bar coater to form a coating film. More specifically, a dilution of the above adhesive was prepared by diluting it with ethyl acetate so that the active ingredient was 30%. This dilution of the adhesive was used and applied at room temperature so that the solid coating amount after solvent evaporation was adjusted to 2.0 to 2.5 g/m ² to form a coating film. After the solvent of the coating film was evaporated in a drying oven, the coated surface was attached 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 humidity 60% RT to 80% RT to obtain a laminate having an OPP/adhesive layer/CPP configuration.

On the OPP film surface of the obtained laminate, the inks of Examples 1 to 29 and Comparative Examples 1 to 12 were printed using an RI tester (a simple color development device manufactured by Akebono Seisakusho Co., Ltd.) so as to give a coating amount of ² to 3 g/m 2. 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 having a configuration of ink layer (cured coating film)/OPP/adhesive layer/CPP.
Next, the obtained printed matter was cut into 9 cm x 9 cm pieces, and the three pieces were stacked so that the printed surface and the non-printed surface were in contact with each other, and the three pieces were kept for 10 days under 25 ° C and 50% environmental conditions with a load of 1 kg / dm ^2. Then, the central printed matter of the three pieces was taken out and set in a migration cell so that 50 ml of 95% ethanol was in contact with the area of the non-printed surface of 0.5 dm ^2. Then, the residual monomer (unreacted (meth)acrylate component) was extracted at 60 ° C for 10 days while stirring. The migration cell was completely sealed by the instrument, and the loss of the contents and the mixing of other components into the contents (extract) in the above process can be completely suppressed.
Next, the above 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 to determine the concentration of each of the (meth)acrylate compounds as the (meth)acrylate component (A) present in the ethanol. Furthermore, the migration resistance was evaluated according to the following criteria. The industrially practical level is "3" or higher, with "4" or higher being more preferable.

(Evaluation Criteria for Migration Resistance)
5: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound with the highest migration amount is less than 10 ppb. 4: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound with the highest migration amount is 10 ppb or more and less than 25 ppb. 3: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound with the highest migration amount is 25 ppb or more and less than 50 ppb. 2: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound with the highest migration amount is 50 ppb or more and less than 100 ppb. 1: Among the (meth)acrylate components (A), the concentration of the (meth)acrylate compound with the highest migration amount is 100 ppb or more.

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

(Film strength test)
The surfaces of the prints obtained by printing the inks of Examples 1 to 29 and Comparative Examples 1 to 12 were rubbed with a cotton swab immersed in a 99.5% ethanol solution at a rate of one reciprocation per second, and the number of reciprocations 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 times or more 4: 50 times or more but less than 100 times 3: 30 times or more but less than 50 times 2: 10 times or more but less than 30 times 1: Less than 10 times

(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 fixed conditions other than the printing speed, and then the printing speed was increased to 200 m/min. The initial density stability was evaluated on a 5-point scale based on the density fluctuation observed when 500 m was printed, according to the following criteria: A practical 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

(Background stain resistance test)
In the above printing test, as the printing length increases, ink gradually adheres to the roller supplying dampening water. As the amount of dampening water supplied decreases, ink tends to be applied to non-image areas (areas where ink should not be applied) where images are formed on the printed matter. From these results, as the printing length increases, stains tend to occur on the printed matter. For the above reasons, the water dial was set to a value 2% higher than the lower limit of the water width, and the printed matter 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: After printing 8,000m, no noticeable staining was observed on the film.
4: When printing 6,000 m or more but less than 8,000 m, scumming occurs in non-image areas.
3: When printing 4,000 m or more but less than 6,000 m, scumming occurs in non-image areas.
2: When printing 2,000 m or more and 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.

As described above, the present invention has been able to provide an electron beam curable composition that imparts excellent adhesion to each film substrate, imparts low migration properties and transport resistance that are important in the packaging market, and is also safe for health and the environment, as well as a laminate using the electron beam curable composition. It has also been able to provide an electron beam curable composition that has excellent printability when used as an ink.

Claims (12)

The composition 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);
The resin (A) contains at least one selected from the group consisting of a rosin-modified resin, a diallyl phthalate resin, a polyester resin, and a urethane (meth)acrylate resin ;
the (meth)acrylate compound (B) contains at least one member selected from the group consisting of an amine-modified (meth)acrylate and a polyester (meth)acrylate ,
1. An electron beam curable composition, comprising: a (meth)acrylate compound having a weight average molecular weight of less than 500 in an amount of 25 mass % or less based on the total mass of the composition. The electron beam curable composition according to claim 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. 2. The electron beam curable composition according to claim 1, which does not contain a benzoxazole-based fluorescent brightening agent . The electron beam curable composition according to claim 1, wherein the (meth)acrylate compound (B) includes an amine-modified (meth)acrylate. The electron beam curable composition according to claim 1, wherein the (meth)acrylate compound (B) includes a polyester (meth)acrylate. The electron beam curable composition according to claim 1, wherein 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 electron beam curable composition according to claim 1, which is substantially free of a photopolymerization initiator. The electron beam curable composition according to claim 1, which is substantially free of organic solvents. The electron beam curable composition according to claim 1, which is substantially free of polytetrafluoroethylene wax. A laminate comprising a substrate and a cured product of the electron beam curable composition according to any one of claims 1 to 9. The laminate according to claim 10, wherein the substrate is a film or paper. A method for producing a laminate, 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.