Active energy ray-curable adhesive composition, method for producing laminate, laminate, and packaging material using same

Abstract

The present invention addresses the problem of providing an environmentally friendly active energy ray-curable adhesive composition that has excellent curability, a cured film of which is flexible, and that can actualize adequate adhesion even to a film lacking an easy-adhesion layer and providing a laminate suited to a packaging material and proposes an active energy ray-curable adhesive composition containing a conjugated diene polymer (A) that is liquid at 25°C, 1 atm, a polyfunctional (meth)acrylate (B), a polyol compound (C), and a polyisocyanate compound (D) and proposes a laminate using the composition and the application thereof to a packaging material.

Description

Active energy ray-curable adhesive composition, method for producing laminate, laminate, and packaging material using the same

[0001] The present invention relates to an active energy ray-curable adhesive composition, a method for producing a laminate, a laminate, and a packaging material using the laminate.

[0002] With the global population increasing, demand for flexible packaging, which is primarily used for packaging food and daily necessities, is expected to continue to grow. In flexible packaging, from the perspectives of protecting the contents, improving impact resistance, and providing heat-sealing properties, it is common to laminate printed materials (hereinafter also referred to as "printed film materials") onto plastic films, metal foils, heat-melting films (sealants), etc., which impart the properties required for each application.

[0003] It has been proposed that film prints are typically bonded to other materials using a laminating adhesive containing a polyisocyanate component and a polyol component, resulting in laminates and printed packaging that have excellent solvent resistance, even against highly polar solvents (Patent Document 1). However, because such laminating adhesives contain large amounts of organic solvents, such as toluene and ethyl acetate, during coating, a large amount of energy is required for drying the solvent and exhaust treatment, resulting in a significant environmental impact. Furthermore, in recent years, there has been a demand for reducing the volatile components contained in adhesives in response to environmental issues and carbon neutrality.

[0004] Therefore, Patent Document 2 proposes a laminate film using an active energy ray-curable adhesive that is made by blending an aromatic acrylic acid ester monomer and a resin.

[0005] Patent No. 5657990 Specification JP-A-8-253736

[0006] However, in Patent Document 2, although a laminate film is formed by irradiation with an electron beam, the cured film lacks flexibility after the adhesive is cured. Also, the film that can be used is limited to product numbers that require an easy-adhesion layer, which is a drawback in that it is poor in versatility.

[0007] Therefore, an object of the present invention is to provide an active energy ray-curable adhesive composition that has excellent curability, produces a cured film that has flexibility, and is capable of exhibiting sufficient adhesion even to films that do not have an easy-adhesion layer, and that has a low environmental impact.

[0008] The present invention provides an active energy ray-curable adhesive composition comprising a conjugated diene polymer (A) that is liquid at 25°C and 1 atmosphere, a polyfunctional (meth)acrylate (B), a polyol compound (C), and a polyisocyanate compound (D).

[0009] The present invention also provides a method for producing a laminate, comprising the steps of: bonding films of the same type or different types together via the active energy ray-curable adhesive composition of the present invention to form a laminate film; irradiating the laminate film with active energy rays; and curing the laminate film irradiated with active energy rays, in this order.

[0010] The present invention also provides a method for producing a laminate, comprising, in this order: a step of applying the active energy ray-curable adhesive composition of the present invention to a film; an irradiation step of irradiating the film coated with the adhesive composition with active energy rays; a lamination step of laminating and adhering a film of the same type or a different type to the surface of the film irradiated with active energy rays, on which the adhesive composition was coated, to form a laminate film; and an aging step of curing the laminated film.

[0011] The present invention also provides a laminate comprising at least a first resin layer containing a resin as a main component, a second resin layer containing a polyolefin as a main component as a resin component, and a layer (referred to as a "first intermediate layer") which is present between the first resin layer and the second resin layer and which contains a resin as a main component, wherein the second resin layer has a lower melting point than the first resin layer, and the first intermediate layer contains at least polyurethane and a compound having an aliphatic carbon-carbon double bond, and the laminate film has a melting point of 1600 to 1650 cm when observed by transmission infrared spectroscopy. －１ The maximum peak height (A) in the range of 1700 to 1750 cm －１The ratio ((A) / (B)) of the maximum peak height (B) in the range of 0.05 to 0.40 is the laminate.

[0012] The active energy ray-curable adhesive composition according to the present invention has excellent curability, and the cured film has flexibility, and can exhibit sufficient adhesion even to a film that does not have an easy-adhesion layer.

[0013] The present invention will be specifically described below. In the present invention, "or more" means the same as or greater than the indicated numerical value. Furthermore, "or less" means the same as or smaller than the indicated numerical value. Furthermore, "(meth)acrylate" is a general term including acrylate and methacrylate, and "(meth)acryloyl group" is a general term including acryloyl group and methacryloyl group.

[0014] The active energy ray-curable adhesive composition of the present invention contains a conjugated diene polymer (A) (hereinafter sometimes simply referred to as "conjugated diene polymer (A)") that is liquid at 25°C and 1 atmosphere. The conjugated diene polymer (A) serves to impart rubber elasticity to the cured film after curing of the adhesive composition, thereby improving the flexibility of the cured film after curing of the active energy ray-curable adhesive composition. A dispersion of rubber-elastic latex is known as a material that has a similar effect. However, compared to the use of such a dispersion, the conjugated diene polymer (A) used in the present invention is liquid at 25°C and 1 atmosphere, resulting in less coloration and excellent transparency. Therefore, when used as a flexible packaging material, it exhibits less light scattering and a good appearance. Furthermore, the conjugated diene polymer (A) is highly compatible with the other components of the adhesive composition of the present invention, the polyfunctional (meth)acrylate (B), the polyol compound (C), and the polyisocyanate compound (D), and thus provides excellent handleability in addition to the optical properties of the cured film.

[0015] The conjugated diene polymer (A) preferably has a (meth)acryloyl group at its terminal or side chain, because this improves curability against active energy rays, enables crosslinking with the polyfunctional (meth)acrylate (B), another essential component, and improves the flexibility of the cured film of the active energy ray-curable adhesive composition. Examples of methods for introducing a (meth)acryloyl group at the terminal or side chain include the methods described below.

[0016] The conjugated diene polymer (A) preferably has a glass transition temperature (Tg) of −80° C. or higher and −20° C. or lower, since this imparts flexibility to a cured film of the active energy ray-curable adhesive composition and also improves adhesion to films.

[0017] The conjugated diene polymer (A) preferably has a weight-average molecular weight of 10,000 or more, since this imparts flexibility to a cured film of the active energy ray-curable adhesive composition and improves adhesion to the film. On the other hand, the weight-average molecular weight is preferably 50,000 or less, since this improves compatibility with other components, thereby suppressing an increase in viscosity of the active energy ray-curable adhesive composition, and also provides excellent handleability.

[0018] The conjugated diene polymer (A) imparts flexibility to a cured film obtained after curing of the active energy ray-curable adhesive composition and can also improve adhesion to a film used for lamination, so the conjugated diene polymer (A) is preferably contained in an amount of 5% by mass or more, more preferably 10% by mass or more, based on 100% by mass of the active energy ray-curable adhesive composition. Furthermore, in order to suppress a decrease in curability and an increase in viscosity of the active energy ray-curable adhesive composition, the conjugated diene polymer (A) is preferably contained in an amount of 30% by mass or less, more preferably 20% by mass or less.

[0019] The conjugated diene polymer (A) used in the present invention is a polymer or copolymer of one or more conjugated dienes, and a copolymer of a conjugated diene and a monomer copolymerizable with the conjugated diene. It also includes derivatives obtained by introducing additional functional groups into the terminals or side chains of the above polymers and copolymers. In other words, it refers to a polymer having a conjugated double bond in the main chain skeleton. Specific examples include polymers of 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, piperylene, etc., and either a homopolymer or copolymer thereof, or a copolymer of a conjugated diene and a vinyl monomer, may be used. Particularly preferred are polymers and copolymers using 1,3-butadiene or isoprene as the conjugated diene. Examples of the vinyl monomer that can be used include styrene, alkylstyrene, acrylonitrile, (meth)acrylate esters, (meth)acrylic acid, maleic anhydride, etc. In particular, when the conjugated diene polymer (A) has a (meth)acryloyl group, it can be obtained by copolymerizing a conjugated diene using glycidyl (meth)acrylate, (meth)acrylic acid, maleic anhydride, or the like as a vinyl monomer, and then subjecting the copolymer to an addition reaction with (meth)acrylic acid or glycidyl (meth)acrylate.

[0020] As such a conjugated diene polymer (A), the above-mentioned synthetic products or commercially available products may be used. Commercially available products include "Kuraplane" (registered trademark) KL-10, LIR-30, LIR-50, LIR-290, LIR-310, LIR-390, LIR-403, LIR-410, UC-102M, UC-203M, LBR-300, LBR-302, LBR-305, LBR-307, LBR-352, LBR-361, L-SBR-820, and L-SBR-841 manufactured by Kuraray Co., Ltd., "Poly bd" (registered trademark) R-15HT and R-45HT, "Poly ip" (registered trademark), and "EPOL" (registered trademark) manufactured by Idemitsu Kosan Co., Ltd., "Nipol" (registered trademark) 1312 manufactured by Nippon Zeon Co., Ltd., and "NISSO" (registered trademark) manufactured by Nippon Soda Co., Ltd. Examples of such PB" (registered trademark) B-1000, B-2000, B-3000, G-1000, G-2000, G-3000, BI-2000, BI-3000, JP-100, JP-200, TE-2000, TEAI-1000, GQ-1000, SARTOMER CN301, CN303, CN307, CN9014, H.B. Fuller's "KALENE" (registered trademark) 800, 1300, "ISOLENE" (registered trademark) 40-S, 400-S, and Osaka Organic Chemical Industry's BAC-15 and BAC-45. Examples of conjugated diene polymers having a (meth)acryloyl group include UC-102M, UC-203M, TE-2000, TEA-1000, TEAI-1000, BAC-15, and BAC-45.

[0021] The active energy ray-curable adhesive composition of the present invention contains a polyfunctional (meth)acrylate (B). The polyfunctional (meth)acrylate (B) is cured by irradiation with active energy rays and contributes to film formation. From the viewpoint of curability, the polyfunctional (meth)acrylate (B) is preferably one having high reactivity. Furthermore, from the viewpoint of safety and the environment, it is preferably one having low volatility. Low volatility refers to a weight loss rate of 1% by weight or less when heated at 110°C for 1 hour, as defined by Method 24 of the U.S. Environmental Protection Agency (EPA).

[0022] The polyfunctional (meth)acrylate (B) used in the present invention is a compound having a plurality of (meth)acryloyl groups in the molecule, and specific examples of bifunctional (meth)acrylates include 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, bisphenol A di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and the like. acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, diglycerin di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate.

[0023] Examples of trifunctional (meth)acrylates include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, isocyanuric acid tri(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate.

[0024] Examples of tetrafunctional (meth)acrylates include ditrimethylolpropane tetra(meth)acrylate, diglycerin tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate.

[0025] Examples of the penta- or higher functional (meth)acrylate include dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate.

[0026] The alcohol-derived component of these polyfunctional (meth)acrylates may be an alkylene oxide adduct of a polyol such as ethylene oxide or propylene oxide, for example, which has a hydroxyalkyleneoxy group or a hydroxypoly(alkyleneoxy) group instead of a hydroxyl group, such as polyoxyethylene glycerin ether.

[0027] The polyfunctional (meth)acrylate (B) does not contain any conjugated double bonds derived from a diene.

[0028] The polyfunctional (meth)acrylate (B) preferably has a tertiary amino group, since this can improve adhesion to the substrate film. It is presumed that the tertiary amino group strongly interacts with polar groups, such as hydroxyl groups, on the film surface, particularly carboxyl groups, thereby improving the adhesion of the cured film of the active energy ray-curable adhesive composition to the film. Furthermore, in the polyurethane-forming reaction described below, the tertiary amino group contained in the (meth)acrylate (B) also functions as a catalyst, thereby accelerating the reaction and shortening the curing time. Furthermore, compared to the simple coexistence of a catalyst, the (meth)acrylate (B) is cured by active energy rays and incorporated into the cured film via a covalent bond, which has the advantage of low migration.

[0029] Examples of such polyfunctional (meth)acrylates having a tertiary amino group include EBECRYL LEO 10101, EBECRYL LEO 10551, EBECRYL LEO 10552, EBECRYL LEO 10553, EBECRYL 80, EBECRYL 81, EBECRYL 83, EBECRYL 85, EBECRYL 880, and EBECRYL 7100 manufactured by Daicel Allnex Co., Ltd.; ETERCURE manufactured by Eternal Corporation; 63922, CN549NS, CN550, CN551NS manufactured by SARTOMER, AgiSyn701, AgiSyn701P, AgiSyn703, AgiSyn703TF manufactured by DSM, Miramer AS1000, Miramer AS3500, Miramer LR3600, Photocryl A104, Photocryl DP143 manufactured by Miwon, etc. Alternatively, they can also be synthesized by subjecting a secondary amine to a Michael addition reaction with a polyfunctional (meth)acrylate.

[0030] The polyfunctional (meth)acrylate (B) is preferably at least one selected from di(meth)acrylates having an alicyclic skeleton and di(meth)acrylates having 9 to 18 carbon atoms, since these have excellent compatibility with the conjugated diene polymer (A) that is liquid at 25°C and 1 atmosphere.

[0031] Examples of such polyfunctional (meth)acrylates include 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate, with tricyclodecane dimethanol di(meth)acrylate being particularly preferred.

[0032] The polyfunctional (meth)acrylate (B) improves the curability with active energy rays, and therefore is preferably contained in an amount of 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, when the mass of the active energy ray-curable adhesive composition is taken as 100% by mass.

[0033] The active energy ray-curable adhesive composition of the present invention contains a polyol compound (C). The polyol compound (C) used in the present invention refers to a compound having two or more hydroxyl groups, and does not contain a conjugated double bond derived from a diene.

[0034] Specific examples of the polyol compound (C) include neopentyl glycol, 1,3-butanediol, 1,4-butanediol, tripropylene glycol, tetramethylene glycol, glycerin, trimethylolpropane, pentaerythritol, ditrimethylolpropane, diglycerin, dipentaerythritol, ethylene oxide adducts, propylene oxide adducts, tetraethylene oxide adducts, and lactone adducts.

[0035] In addition, the polyol compound (C) is preferably a polyester polyol, since this improves the heat resistance and coating film properties of the active energy ray-curable adhesive composition and can impart resistance to boiling and retort treatments.

[0036] The polyester structure in the polyester polyol can be obtained by reacting a dicarboxylic acid derivative with a diol. Specific examples of the dicarboxylic acid derivative include phthalic acid, isophthalic acid, terephthalic acid, adipic acid, oxalic acid, maleic acid, fumaric acid, and sebacic acid. These can be reacted with a diol to form a polyester structure, and polyester polyols with terminal hydroxyl groups can be used.

[0037] Additionally, polyol compounds having a carbonate structure can also be used. Specific examples include pentamethylene carbonate diol, hexamethylene carbonate diol, hexane carbonate diol, and decane carbonate diol. These polyol compounds can be used alone or in combination of two or more.

[0038] The molecular weight of the polyol compound (C) is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more, from the viewpoint of improving adhesion through a higher molecular weight, while it is preferably 10,000 or less, more preferably 7,000 or less, and even more preferably 5,000 or less, from the viewpoint of increasing the fluidity of the adhesive composition and improving its coatability.

[0039] The active energy ray-curable adhesive composition of the present invention contains a polyisocyanate compound (D). The polyisocyanate compound (D) used in the present invention refers to a compound having two or more isocyanate groups, and can be made into a high molecular weight compound by an addition reaction. It does not contain a conjugated double bond derived from a diene. By blending the polyol compound (C) and the polyisocyanate compound (D) in the active energy ray-curable adhesive composition of the present invention, they react with each other after application to an adherend to form a polyurethane.

[0040] Specific examples of the polyisocyanate compound (D) include toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4-methylenebiscyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, and trimethylhexamethylene diisocyanate. Nurate-modified, adduct-modified, biuret-modified, and allophanate-modified products of these polyisocyanate compounds can also be used. These diisocyanates can also be used alone or in combination of two or more.

[0041] The weight average molecular weight of the polyisocyanate compound (D) is preferably 500 or more, more preferably 1000 or more, and even more preferably 2000 or more, from the viewpoint of suppressing elution when the polyisocyanate compound (D) remains in the cured product of the adhesive composition. On the other hand, the weight average molecular weight of the polyisocyanate compound (D) is preferably 10000 or less, more preferably 7000 or less, and even more preferably 5000 or less, from the viewpoint of increasing the fluidity of the adhesive composition and improving the coatability.

[0042]

[0044] The total content of the polyol compound (C) and the polyisocyanate compound (D) in the active energy ray-curable adhesive composition of the present invention is preferably 50% by mass or more, and more preferably 60% by mass or more, when the mass of the active energy ray-curable adhesive composition is taken as 100% by mass, from the viewpoint of improving the adhesion of the final laminate film. Furthermore, in order to reduce the curability to active energy rays and the viscosity of the adhesive composition, the total content is preferably 80% by mass or less, and more preferably 70% by mass or less.

[0043] The equivalent ratio between the polyol compound (C) and the polyisocyanate compound (D) is preferably such that the content of isocyanate groups in the polyisocyanate compound is 0.8 mol or more and 1.2 mol or less per 1.0 mol of hydroxyl groups in the polyol compound (C). The closer the equivalent ratio, the more the chain extension reaction proceeds, and the higher the molecular weight of the resulting polyurethane becomes, thereby improving adhesion.

[0044] The active energy ray-curable composition of the present invention preferably contains a photopolymerization initiator depending on the active energy ray source. Examples of the photopolymerization initiator that can be used include α-aminoalkylphenones, thioxanthones, benzyl ketals, and acylphosphine oxides.

[0045] The active energy ray-curable adhesive composition of the present invention preferably contains substantially no solvent and no monofunctional (meth)acrylate. The term "solvent" as used herein refers to a compound other than the conjugated diene polymer (A), the polyfunctional (meth)acrylate (B), the polyol compound (C), and the polyisocyanate compound (D), which is liquid at 1 atmosphere and 25°C and has a boiling point at 1 atmosphere of 200°C or lower. Furthermore, "substantially free of solvent and no monofunctional (meth)acrylate" as used herein means that the total content of the solvent and the monofunctional (meth)acrylate in the active energy ray-curable adhesive composition is 0.1 mass% or less. The active energy ray-curable adhesive composition of the present invention is substantially free of solvent, which improves the curability of the adhesive composition against active energy rays. Furthermore, it is possible to prevent the solvent from passing through the printed film and transferring to the contents. Specific examples of the solvent include alcohols such as ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol; esters such as ethyl acetate, propyl acetate, butyl acetate, amyl acetate, propyl propionate, and butyl propionate; glycols such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol dimethyl ether, and propylene glycol monomethyl ether acetate; and ketones such as acetone and methyl ethyl ketone.

[0046] The active energy ray-curable composition of the present invention may contain additives such as wax, surfactant, antifoaming agent, and leveling agent as other components.

[0047] The acrylic equivalent of the active energy ray-curable composition of the present invention is preferably 150 g / eq or more and 500 g / eq or less. When the acrylic equivalent is 150 g / eq or more, more preferably 200 g / eq or more, and even more preferably 250 g / eq or more, storage stability is improved. Furthermore, when the acrylic equivalent is 500 g / eq or less, more preferably 450 g / eq or less, and even more preferably 400 g / eq or less, curability with active energy rays is good. In the present invention, the acrylic equivalent represents the number of grams (unit: g / eq) of the active energy ray-curable composition required to obtain 1 mole of (meth)acryloyl groups contained in the active energy ray-curable composition.

[0048] The viscosity of the active energy ray-curable composition of the present invention is preferably low because the composition is applied using a laminator, resulting in a good appearance after application. Since some equipment, such as a non-sol laminator, can heat the composition using a roll, the specific viscosity is preferably 100 mPa·s or more and 10,000 mPa·s or less at a temperature ranging from 25°C to 80°C.

[0049] Next, a method for producing the active energy ray-curable adhesive composition of the present invention will be described with reference to an example, although the present invention should not be construed as being limited to such an example.

[0050] The active energy ray-curable adhesive composition of the present invention can be obtained by mixing the conjugated diene polymer (A), the polyfunctional (meth)acrylate (B), the polyol compound (C), the polyisocyanate compound (D), and, if necessary, other components, at room temperature to 80° C. Suitable ranges for the contents of each component are, when the mass of the active energy ray-curable adhesive composition is taken as 100 mass%, 10 to 20 mass% of the conjugated diene polymer (A), 10 to 20 mass% of the polyfunctional (meth)acrylate (B), and 60 to 70 mass% in total of the polyol compound (C) and the polyisocyanate compound (D).

[0051] After mixing or during the mixing process, degassing is preferably carried out under vacuum or reduced pressure conditions.

[0052] In addition, when the polyol compound (C) and the polyisocyanate compound (D) are mixed, a polyurethane-forming reaction may proceed depending on environmental conditions and other conditions, and in that case the composition begins to thicken. Therefore, it is practically preferable to prepare a liquid A of the polyisocyanate compound (D) and a liquid B prepared by mixing other components, mix the two liquids immediately before use, and use the resulting adhesive composition in a laminator.

[0053] One embodiment of the method for producing a laminate of the present invention includes, in this order, a laminating step of bonding films of the same type or different types together via the active energy ray-curable adhesive composition of the present invention to form a laminate film, an irradiation step of irradiating the laminate film with active energy rays, and an aging step of curing the film irradiated with active energy rays.

[0054] In the laminating step, the active energy ray-curable adhesive composition of the present invention is applied to one of the films, and the other film is laminated onto the wet coating to obtain a laminate film. One of the films is preferably a printed material with ink printed thereon, and the other film is preferably a sealant.

[0055] Another embodiment of the method for producing a laminate of the present invention includes, in this order, a step of applying an active energy ray-curable adhesive composition to a film, an irradiation step of irradiating the film coated with the adhesive composition with active energy rays, a lamination step of laminating and adhering a film of the same type or a different type to the surface of the film irradiated with the active energy rays, on which the adhesive composition was applied, to form a laminate film, and an aging step of curing the laminated film.

[0056] The latter method is preferable because, by irradiating the film coated with the adhesive composition with active energy rays, the other film to be bonded to the adhesive composition can be prevented from being exposed to active energy rays, thereby avoiding damage to the film.Furthermore, since there is nothing to block the active energy rays when the adhesive composition is irradiated with the active energy rays, the attenuation of the active energy rays can be minimized.

[0057] Examples of films that can be used in the laminate of the present invention include polyesters such as polyethylene, polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate, and polylactic acid, polyamide, polyimide, polyalkyl(meth)acrylate, polystyrene, poly-α-methylstyrene, polycarbonate, polyvinyl alcohol, polyvinyl acetal, polyvinyl chloride, and polyvinylidene fluoride. Among these, polyolefins are known as materials with low environmental impact and are suitable for use as packaging materials, but have been criticized for being deficient in gas barrier properties, mechanical properties, and the like. However, as will be described later, the present invention can provide a laminate that can compensate for these deficiencies, and therefore polyolefins can be preferably used.

[0058] These films may also have a vapor-deposited thin film layer of a metal such as alumina or a metal compound.

[0059] The surface of the film is preferably corona-treated, since this increases the polar functional groups on the film surface and improves adhesion to the active energy ray-curable adhesive composition. In addition, when the film is a printed material, the surface of the plain part is preferably corona-treated.

[0060] The film having a corona-treated surface may be a ready-made product, or may be a film that has been subjected to in-line corona treatment before printing or lamination.

[0061] The film may have an easy-adhesion coating layer, but this increases costs. However, the active energy ray-curable adhesive composition of the present invention is suitable because it can exhibit sufficient adhesion even to a film that does not have an easy-adhesion layer.

[0062] The film may be in the form of either a sheet or a roll film. When a thin film for flexible packaging is used, it is preferable to use a roll film and apply coating and printing by roll-to-roll.

[0063] In the irradiation step, the (meth)acryloyl groups react with the active energy rays and are crosslinked by covalent bonds, thereby instantly curing the active energy ray-curable adhesive composition.

[0064] The active energy ray source used in the irradiation step includes ultraviolet rays, electron beams, gamma rays, etc. In particular, electron beams are preferred because they do not require an initiator, do not require special qualifications for use, and are easy to handle.

[0065] For ultraviolet light, ultraviolet irradiation devices such as high-pressure mercury lamps, xenon lamps, metal halide lamps, and light-emitting diodes (LEDs) are preferably used. Among these, LED lamps are preferred because they are energy-saving and generate little ozone. As for the wavelength of the LED, an emission line of 350 to 420 nm is preferred from the viewpoints of energy saving and cost reduction.

[0066] Electron beams directly excite (meth)acryloyl groups into radicals, causing radical polymerization in the active energy ray-curable adhesive composition to form a film. Radiation is also highly permeable and can also affect films. When the film is made of polyolefins, radicals are easily generated, causing reactions such as intermolecular crosslinking and decomposition. Radiation then progresses between the active energy ray-curable adhesive composition and the film, resulting in the formation of covalent bonds between the active energy ray-curable adhesive composition and the film, resulting in higher adhesion. Electron beams using low acceleration voltages are particularly preferred because they require no special qualifications for use and are easy to handle. Since the penetration depth of electron beams is determined by the acceleration voltage, an acceleration voltage of 50 kV to 300 kV is preferred from the standpoints of sufficient penetration and damage to the film. Furthermore, the electron beam irradiation dose is preferably 10 kGy or more and 100 kGy or less, because while the amount of radical species generated in the target material increases, damage to the film also increases.

[0067] In the aging step, by performing heat treatment in an environment of 40°C or higher and 60°C or lower, the reaction between the polyol compound (C) and the polyisocyanate compound (D) in the adhesive composition proceeds, and the molecular weight increases, thereby making it possible to further improve the adhesion.

[0068] A laminate according to one embodiment of the present invention includes a first resin layer containing a resin as a main component. In the description of this specification, the term "main component" refers to the component that is contained in the largest amount by mass unless otherwise specified. A typical embodiment includes a case where the component is present in an amount of more than 50% by mass, preferably more than 70% by mass.

[0069] The resin constituting the first resin layer preferably contains polyolefin as a main component. Examples of polyolefin include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polypropylene (PP), and mixtures thereof. These may be unstretched, uniaxially stretched, or multiaxially stretched. They may also be laminates of two or more layers. The selection of the raw olefin is primarily determined by the intended use as a packaging material. Generally, oriented polypropylene film, biaxially stretched polyethylene film, or uniaxially stretched polyethylene film is preferably used, as they are rigid and difficult to stretch during transportation during printing or lamination. In transmission infrared spectroscopy, polyethylene has a wavelength of 700 to 750 cm. －１ C-H bending vibration, 1400-1500 cm －１ C-H bending vibration, 2800-3000 cm －１ Polypropylene has a C-H stretching vibration of 700-750 cm －１ C-H bending vibration, 950-1000 cm －１ Hybrid vibration of C-H stretching and C-H bending, 1150-1200 cm －１ C-H bending vibration, 1350-1400 cm －１ to C-CH ３ Bending angle vibration, 1400-1500cm －１ C-H bending vibration, 2800-3000 cm －１ Both polyethylene and polypropylene exhibit C-H stretching vibrations in the range of 1500 to 2500 cm －１ and 3100-4000 cm －１ It has no major absorption peak in the region

[0070] The olefin preferably used for the first resin layer may contain recycled raw materials or biomass-derived (plant-derived) raw materials. It may also be a mixture of these with chemical fuel-derived raw materials, and preferably contains 10 to 95 mass % of biomass-derived raw materials based on the total raw materials.

[0071] When the first resin layer is mainly composed of polyolefin, the density of the first resin layer is set to 0.93 g / cm3 from the viewpoints of post-processability and heat resistance. ３ It is preferable that this is equal to or greater than this.

[0072] The first resin layer is preferably subjected to a surface treatment such as corona treatment, burning treatment, or plasma treatment to improve wettability and adhesion to printing ink and the first intermediate layer described below.

[0073] The first resin layer preferably has an inorganic layer or a water-soluble resin layer because it improves gas barrier properties and can enhance the shelf life of the contents when used as a packaging material. An anchor layer may also be provided to improve adhesion between these layers and the first resin layer. When the first resin layer is primarily composed of polyolefin, this effect is significant.

[0074] The inorganic layer refers to a layer containing an inorganic compound. Examples of inorganic compounds include aluminum, magnesium, titanium, tin, indium, silicon, zinc, and oxides thereof. Among these, aluminum oxide is preferred from the viewpoints of heat resistance and acid resistance to the contents. The inorganic layer can be formed by vapor deposition, sputtering, plasma vapor deposition, or the like.

[0075] The water-soluble resin layer refers to a cured layer containing a water-soluble resin. Examples of the water-soluble resin include polyvinyl alcohol and ethylene-vinyl alcohol copolymer, which primarily enhance oxygen barrier properties. The water-soluble resin layer may also contain condensates obtained by sol-gel reactions of silicon alkoxide, aluminum alkoxide, titanium alkoxide, and the like. The inclusion of the condensates primarily improves water vapor barrier properties.

[0076] The first resin layer, including the case where the first resin layer is mainly composed of polyolefin, is preferably 10 μm or more in order to have mechanical properties suitable for printing, and is preferably 100 μm or less in terms of cost.

[0077] The first resin layer may be in the form of either a sheet or a roll film, including a case in which the first resin layer is mainly composed of polyolefin. In flexible packaging applications, it is preferable to use a roll film and process it in a roll-to-roll manner from the viewpoint of productivity.

[0078] The laminate of the present invention includes a second resin layer containing polyolefin as a main component, and the second resin layer has a lower melting point than the first resin layer.

[0079] The second resin layer (hereinafter, for convenience, may be referred to as the "second polyolefin layer") has a lower melting point than the first resin layer, and therefore can be joined by heat sealing after arranging the second polyolefin layers face to face (hereinafter, referred to as "heat sealable"), and can be molded into a desired shape, such as a bag, allowing the laminate of the present invention to be used as a packaging material. Furthermore, this configuration makes it easy to print on the surface of the first resin layer facing the second polyolefin layer, and can impart a design and protect the printed surface, thereby suppressing deterioration over time.

[0080] Polyolefins that can be used for the second polyolefin layer include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), polypropylene (PP), and mixtures thereof, which may be unstretched, uniaxially stretched, or multiaxially stretched. A laminate of two or more layers may also be used. The choice of raw olefin is primarily determined by the intended use as a packaging material. Since flexibility is generally required as a sealant, unstretched polypropylene film or unstretched polyethylene film is preferably used. From the viewpoint of recyclability, it is particularly preferred that the first resin layer be primarily composed of polyolefin and be a resin obtained from the same olefin species as the polyolefin.

[0081] The polyolefin used in the second polyolefin layer may contain recycled materials or biomass-derived (plant-derived) materials. It may also be a mixture of these with chemical fuel-derived materials, and preferably contains 10 to 95 mass % of biomass-derived materials based on the total mass of the materials.

[0082] The polyolefin used in the second polyolefin layer is preferably subjected to a surface treatment such as corona treatment, burning treatment, or plasma treatment in order to improve wettability with the adhesive.

[0083] The polyolefin used in the second polyolefin layer improves gas barrier properties and enhances the preservation of the contents when used as a packaging material, and therefore may have an inorganic layer or a water-soluble resin layer.

[0084] The second polyolefin layer preferably has a thickness of 30 μm or more in order to provide elongation to the laminate, and preferably has a thickness of 200 μm or less in terms of cost.

[0085] The polyolefin used in the second polyolefin layer can be either a sheet or a roll film. In flexible packaging applications, from the viewpoint of productivity, it is preferable to use a roll film and process it in a roll-to-roll manner.

[0086] The laminate of the present invention includes a layer (first intermediate layer) primarily composed of a resin and located between a first resin layer and a second polyolefin layer. The first intermediate layer contains a polyurethane resin and a compound having an aliphatic carbon-carbon double bond. The term "first" in "first intermediate layer" refers to a distinction from intermediate layers that do not contain a polyurethane resin or a compound having an aliphatic carbon-carbon double bond. This does not preclude the provision of multiple first intermediate layers, for example, layers containing different polyurethane resin types, compound types having an aliphatic carbon-carbon double bond, or polyurethane resin and compound having an aliphatic carbon-carbon double bond in different proportions.

[0087] The polyurethane resin is an addition polymerization product of a polyol compound having two or more hydroxyl groups and a polyisocyanate compound having two or more isocyanate groups. In transmission infrared spectroscopy, the polyurethane exhibits absorption peaks derived from the structural units of the polyisocyanate having two or more isocyanate groups and the polyol having two or more hydroxyl groups, and the peaks at 2200 to 2300 cm derived from the isocyanate. －１ and the peak at 3200 to 4000 cm due to hydroxyl groups. －１ Both of the broad peaks at 1700-1750 cm originating from urethane bonds have disappeared at levels observable by transmission infrared spectroscopy. －１ C═O stretching vibration, and 3100-3300 cm －１ The peak of the N--H stretching vibration can be observed.

[0088] The first intermediate layer contains a compound having an aliphatic carbon-carbon double bond. The compound having an aliphatic carbon-carbon double bond exhibits a peak in the range of 1600 to 1650 cm originating from the C═C stretching vibration of the carbon-carbon double bond in transmission infrared spectroscopy. －１ The peak is shown.

[0089] The laminate of the present invention has a wavelength of 1600 to 1650 cm in transmission infrared spectroscopy. －１ The maximum peak height (A) in the range of 1700 to 1750 cm －１The ratio ((A) / (B)) of the maximum peak height (B) in the range of 1600 to 1650 cm (A) to 1650 cm (B) is 0.05 or more and 0.40 or less. The specific measurement method is as explained in the Examples section. The laminate of the present invention may be subjected to processing such as printing on the surface, but naturally, the portion subjected to such processing is not selected as the measurement point. The first resin layer or the second resin layer may be subjected to processing such as printing on the surface of the laminate. －１ or 1700-1750cm －１ In the case where the first intermediate layer has absorption in the range of (A) / (B), the first resin layer or the second resin layer having absorption in the range may be peeled off, or a resin film having the same composition as the first intermediate layer may be separately synthesized, and the ratio (A) / (B) may be measured.

[0090] The compound having an aliphatic carbon-carbon double bond is preferably a conjugated diene polymer because it has a high ability to soften the first intermediate layer.

[0091] The conjugated diene polymer is preferably made of acrylonitrile as a copolymerization component, since this can improve chemical resistance. －１ It is known that the laminate of the present invention exhibits a characteristic peak at 2100 to 2300 cm in the transparent portion in transmission infrared spectroscopy. －１ The maximum peak height (C) in the range of 1700 to 1750 cm －１ The ratio ((C) / (B)) of the maximum peak height (B) in the range of 0.05 to 0.40 is preferably 0.05 or more and 0.40 or less.

[0092] When the first intermediate layer is obtained by curing through irradiation with active energy rays (a chemical change such as a crosslinking reaction or a condensation reaction induced by active energy rays), the first intermediate layer may contain poly(meth)acrylate, which is a polymer of a polyfunctional (meth)acrylate.

[0093] In transmission infrared spectroscopy, (meth)acrylates have a wavelength of 1600 to 1650 cm －１ C═C stretching vibration peak at 1700-1750 cm －１It is known that the C═O stretching vibration peak appears at the peak of the former peak, but the former peak cannot be observed at the stage of forming a laminate due to the chemical reaction caused by the active energy rays.

[0094] From the viewpoint of design, the laminate of the present invention preferably has ink printed on at least one surface of the first resin layer, including when the first resin layer is mainly composed of polyolefin. This ink printing refers to a state in which the ink is applied and then fixed to the first resin layer by drying or curing.

[0095] The ink is typically one in which a pigment or dye is mixed with a binder, and any of a thermal drying type ink such as a solvent or water-based ink, an oxidative polymerization type oil-based ink, and an active energy ray-curable ink that is cured by irradiation with active energy rays can be used, and among these, an active energy ray-curable ink that requires little energy for drying and has a low environmental impact is preferred.

[0096] In one embodiment of the laminate of the present invention, when printing with the ink is applied to the side of the first resin layer opposite to the side on which the second polyolefin layer is present and exposed to the outside, this constitutes a so-called surface printing configuration. In particular, when an actinic ray-curable ink is used as the ink, it can be said to be suitable for surface printing because of its high coating strength and excellent abrasion resistance.

[0097] Furthermore, even when the first resin layer is primarily composed of polyolefin, a varnish film can be applied on top of the print, protecting the print on the side of the first resin layer opposite the second polyolefin layer and imparting design features such as gloss and matte finish to the exterior. The varnish film can be either a thermally drying varnish, such as a solvent-based or water-based varnish, or an active energy ray-curable varnish that cures upon exposure to active energy rays. Active energy ray-curable varnishes, which require less energy to dry and are environmentally friendly, are preferred. Specific examples include water-based varnishes containing self-emulsifying or surfactant-emulsifying acrylic resins, acrylic epoxy resins, and acrylic amino resins, and active energy ray-curable varnishes containing (meth)acrylate oligomers such as urethane (meth)acrylates, ester (meth)acrylates, and epoxy (meth)acrylates.

[0098] The method for producing the laminate of the present invention is as described above. When a design is imparted to the laminate by printing on the first resin layer, or in the case of a reverse printing configuration, the lamination step is carried out after printing on the first resin layer.

[0099] In the case of a surface-printed structure, printing and varnishing may be performed on a laminate already including the first intermediate layer, or the lamination step may be performed after printing and varnishing the first resin layer. The former is preferred from the viewpoint of productivity.

[0100] The packaging material of the present invention can be obtained using the laminate, and since the second polyolefin layer has heat-sealability, this characteristic is utilized and the packaging material is formed by bonding at the second polyolefin layer.

[0101] As an example of a method for producing the packaging material, a bag-shaped packaging material can be obtained by folding the laminate in half so that the first resin layer is on the outside and the second polyolefin layer is on the inside (content side), and then heat-sealing the ends of the overlapped layers. In another embodiment, two laminates can be overlapped so that the second polyolefin layers face each other, and then heat-sealing the ends. This example of obtaining a bag-shaped packaging material can also be preferably used when the first resin layer is mainly composed of polyolefin.

[0102] Furthermore, depending on the type of heat sealing, side seals, two-sided seals, three-sided seals, four-sided seals, pillow seals, pleated seals, flat bottom seals, square bottom seals, gusset seals, etc. can be used to produce packaging materials of various shapes. For example, self-standing packaging materials (standing pouches) are also possible. The heat sealing method can be any known method, such as bar seals, impulse seals, belt seals, rotary roll seals, high frequency seals, or ultrasonic seals.

[0103] The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to these examples.

[0104] [Measurement and Evaluation Methods] (1) Electron Beam Curability An active energy ray-curable adhesive composition was applied to a film of 2.0 g / m ２ The composition was coated onto a 12 μm thick PET film (E5102 manufactured by Toyobo Co., Ltd.) so that the composition would be cured. Then, using an electron beam irradiation device (EC250 / 30 / 90LS manufactured by Iwasaki Electric Co., Ltd.), the coated surface of the composition was irradiated with electron beams at an acceleration voltage of 110 kV while varying the irradiation dose. The minimum dose at which tackiness disappeared and the composition cured was recorded. The smaller the minimum dose, the better the curability. A dose of 45 kGy or less is practically good, and a dose of 25 kGy or less is particularly good. When the composition did not cure even after irradiation with a dose of 240 kGy, it was recorded as "uncured."

[0105] (2) Viscosity A Brookfield DV-II viscometer equipped with a No. 4 cylinder spindle was used to measure the viscosity of each active energy ray-curable composition at 60°C and 0.5 rpm. From the viewpoint of coatability and printability, the viscosity is preferably 5,000 mPa s or less, and more preferably 1,000 mPa s or less.

[0106] (3) Appearance of Coating Film The appearance of the cured film (corresponding to the intermediate layer) of the active energy ray-curable adhesive composition of the laminate was visually evaluated according to the following criteria: A: No diffused reflection due to bubbles or irregularities was observed, and the appearance was good. B: Very slight diffused reflection due to bubbles or irregularities was observed. C: Diffused reflection due to bubbles or irregularities was observed throughout the entire surface.

[0107] (4) Coating Film Flexibility The laminate was folded in half immediately after (within 5 minutes) irradiation with active energy rays, and the appearance of the cured film (corresponding to the intermediate layer) of the active energy ray-curable adhesive composition was evaluated. The evaluation criteria are as follows: A: No cracks were observed in the film even after repeated folding, and the appearance was good. B: Slight cracks were observed in the film after folding several times. C: Cracks appeared over the entire film after folding only once.

[0108] (5) Peel Strength The laminate was cut into a 15 mm wide strip, and the peel strength was measured on the surface coated with the adhesive composition when peeled at 90° at 300 mm / min using a Tensilon universal testing machine (RTG-1210, manufactured by Orientec Co., Ltd.).

[0109] The peel strength of the sample measured within 30 minutes after curing with active energy rays was evaluated as "initial adhesion." In addition, the peel strength of the sample after aging at 40°C for 72 hours (after curing) was evaluated as "adhesion after curing."

[0110] Regarding initial adhesion, if the peel strength was less than 0.5 N / 15 mm, the adhesion was judged to be insufficient; if it was 0.5 N / 15 mm or more and less than 1.0 N / 15 mm, the adhesion was judged to be good; if it was 1.0 N / 15 mm or more and less than 2.0 N / 15 mm, the adhesion was judged to be even better; and if it was 2.0 N / 15 mm or more, the adhesion was judged to be extremely good.

[0111] Regarding adhesion after curing, if the peel strength was less than 3.0 N / 15 mm, the adhesion was judged to be insufficient, if it was 3.0 N / 15 mm or more but less than 4.0 N / 15 mm, the adhesion was judged to be good, and if it was 4.0 N / 15 mm or more, the adhesion was judged to be extremely good.

[0112] (6) Failure Mode In the peel test after curing in (5) above, the behavior during peeling (failure mode) was also observed. In samples with a multilayer structure using three or more substrate layers, the area where failure occurred during peeling corresponded to the weakest adhesion between the substrates. Evaluation was based on the following A to C. A: The film underwent cohesive failure or rupture. B: The active energy ray-curable adhesive composition layer underwent cohesive failure. C: Peeling occurred between the film / active energy ray-curable adhesive composition layer and the film layer. Here, the "active energy ray-curable adhesive composition layer" refers to a layer formed by curing the active energy ray-curable adhesive composition. Of the above, A is most preferred, B is next most preferred, and C is least preferred.

[0113] (7) Measurement by Transmission Infrared Spectroscopy The laminate sample was sandwiched between sodium chloride plates, and an IR Tracer-100 manufactured by Shimadzu Corporation was used to measure infrared radiation from 600 to 4000 cm by transmission on a portion that was not subjected to processing that would interfere with measurement, such as printing. －１ Range, apodization function is Happ-Genzel function, resolution is 4 cm －１ Transmission infrared absorption measurement was carried out with an accumulation number of 32, and the absorbance at each wave number was calculated. －１ Section: 1700-1750 cm －１ and 2100-2300 cm －１ When a peak is observed in the range of 1600 to 1650 cm, baseline correction is performed at three points in the wavenumber range where no absorption peak is observed, and then the height of the peak top is determined. －１ The maximum peak height (A) in the range of 1700 to 1750 cm －１ The ratio ((A) / (B)) of the maximum peak height (B) in the range of 2100 to 2300 cm －１ The maximum peak height (C) in the range of 1700 to 1750 cm －１The ratio ((C) / (B)) of the maximum peak height (B) in the range of 1600 to 1650 cm was calculated. －１ or 1700-1750cm －１ For those laminates that had absorption in the range of (A) / (B) and (C) / (B) and it was difficult to measure the ratio (A) / (B) and the ratio (C) / (B) directly from the laminate, a resin film having the same composition as the first intermediate layer was separately synthesized, and the ratio (A) / (B) and the ratio (C) / (B) were measured.

[0114] [Conjugated diene polymers (A) that are liquid at 25°C and 1 atmosphere] (A)-1: Polybutadiene ("NISSO-PB" (registered trademark) B-2000, manufactured by Nippon Soda Co., Ltd.), no (meth)acryloyl groups, no nitrile groups, Tg = -29°C, weight average molecular weight 3,500. (A)-2: Polyisoprene ("Kuraray" (registered trademark) LIR-30, manufactured by Kuraray Co., Ltd.), no (meth)acryloyl groups, no nitrile groups, Tg = -63°C, weight average molecular weight 28,000. (A)-3: Polybutadiene ("NISSO-PB" (registered trademark) G-3000, manufactured by Nippon Soda Co., Ltd.), no (meth)acryloyl groups, no nitrile groups, Tg = -15°C, weight average molecular weight 4,100. (A)-4: Side-chain acrylic-modified polyisoprene copolymer ("Kurapren" (registered trademark) UC-203M, manufactured by Kuraray Co., Ltd.), containing (meth)acryloyl groups, no nitrile groups, Tg = -60°C, weight-average molecular weight 35,000. (A)-5: Terminally acrylic-modified polybutadiene copolymer ("NISSO-PB" (registered trademark) TE-2000, manufactured by Nippon Soda Co., Ltd.), containing (meth)acryloyl groups, no nitrile groups, Tg = -9°C, weight-average molecular weight 3,600. (A)-6: Terminally acrylic-modified polybutadiene copolymer (BAC-45, manufactured by Osaka Organic Chemical Industry Ltd.), containing (meth)acryloyl groups, no nitrile groups, Tg = -22°C, weight-average molecular weight 10,000. (A)-7: Nitrile butadiene copolymer (Nipol (registered trademark) 1312 manufactured by Zeon Corporation), no (meth)acryloyl group, containing nitrile group, Tg = -36°C, weight average molecular weight 10,000.

[0115] [Polyfunctional (meth)acrylates (B)] (B)-1: EO (ethylene oxide)-modified trimethylolpropane triacrylate (MIWON Corporation, "Miramer" (registered trademark) M3130) (B)-2: Decanediol diacrylate (Shin-Nakamura Chemical Co., Ltd., "NK Ester" (registered trademark) A-DOD-N) (B)-3: Tricyclodecane dimethanol diacrylate (Daicel Allnex Corporation, "EBECRYL" (registered trademark) 130) (B)-4: Dipentaerythritol hexaacrylate (MIWON Corporation, "Miramer" (registered trademark) M600) subjected to a Michael addition reaction with 1H-benzotriazole (Wakenyaku Co., Ltd.) in an equivalent ratio of 3:1. (B)-5: Amine-modified acrylate ("EBECRYL" (registered trademark) LEO 10552 manufactured by Daicel Allnex Corporation) [Polyol compound (C)] (C): "Takelac" (registered trademark) A-244B manufactured by Mitsui Chemicals [Polyisocyanate compound (D)] (D): "Takenate" (registered trademark) A-244A manufactured by Mitsui Chemicals [Conjugated diene polymer ((A') in the table) solid at 25°C and 1 atmosphere] Conjugated diene polymer solid at 25°C and 1 atmosphere: Acrylonitrile butadiene rubber ("Nipol" (registered trademark) DN219 manufactured by Nippon Zeon Co., Ltd.) [Photopolymerization initiator] Photopolymerization initiator: Bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide ("Irgacure" (registered trademark) 819 manufactured by BASF) [Active energy ray-curable adhesive composition] Each material was weighed according to the composition shown in Table 1, and mixed and dissolved using a hybrid mixer (manufactured by Thinky Corporation) to obtain active energy ray-curable adhesive compositions 1 to 25.

[0116]

[0117]

[0118]

[0119] [Base film] Base film 1: 12 μm thick PET film (E5102 manufactured by Toyobo Co., Ltd.) Base film 2: 15 μm thick polyamide film (ON manufactured by Unitika Ltd.) Base film 3: 12 μm thick barrier film / PET film laminate (1011HG SBR2 manufactured by Toray Advanced Film Co., Ltd.) Base film 4: 20 μm thick oriented polypropylene (OPP) film (FOR manufactured by Futamura Chemical Co., Ltd.) Base film 5: 25 μm thick uniaxially oriented polyethylene (MOPE) film (PE3K-H manufactured by Futamura Chemical Co., Ltd.) Base film 6: 16 μm thick OPP film with barrier layer (AO893 manufactured by Jindal) Base film 7: 20 μm thick biaxially oriented polyethylene (BOPE) film (HD200 manufactured by Jindal) [Heat-sealable film] Heat-sealable film 1: 40 μm thick unstretched polypropylene (CPP) film (P1128 manufactured by Toyobo Co., Ltd.) Heat-sealable film 2: 50 μm thick LLDPE film (LL-XHT manufactured by Futamura Chemical Co., Ltd.) Heat-sealable film 3: 50 μm thick CPP film (ZK207 manufactured by Toray Advanced Film Co., Ltd.) Heat-sealable film 4: 60 μm thick CPP film (ZK207 manufactured by Toray Advanced Film Co., Ltd.) [Laminate manufacturing method 1] As shown in Table 2, Table 3 or Table 4, an active energy ray-curable adhesive composition was applied to the film at 2.0 g / m ２ After coating so that the adhesive composition was uniform, a heat-sealable film was laminated on the adhesive composition. The adhesive composition was then cured by irradiating the adhesive composition from the substrate film side with an electron beam at an acceleration voltage of 110 kV and an exposure dose of 45 kGy using an electron beam irradiation device (EC250 / 30 / 90LS manufactured by Iwasaki Electric Co., Ltd.). The adhesive composition was then aged at 40°C for 72 hours.

[0120] [Laminate manufacturing method 2] As shown in Table 2, Table 3, or Table 4, an active energy ray-curable adhesive composition was applied to a film at a rate of 2.0 g / m ２ Then, a heat-sealable film was laminated onto the coated film. Then, a light-emitting diode ultraviolet irradiation device (UD90 manufactured by Panasonic Devices SUNX Co., Ltd.) was used to apply ultraviolet light at an irradiation intensity of 8 W / cm. ２The adhesive composition was cured by irradiating it with LED-UV light having an irradiation wavelength of 385 nm from the substrate film side, and then aged at 40°C for 72 hours.

[0121] [Laminate manufacturing method 3] As shown in Table 2, Table 3, or Table 4, an active energy ray-curable adhesive composition was applied to a film at a rate of 2.0 g / m ２ After coating the adhesive composition so that the adhesive composition was cured, the adhesive composition was irradiated with an electron beam from the adhesive composition side using an electron beam irradiation device (EC250 / 30 / 90LS manufactured by Iwasaki Electric Co., Ltd.) at an acceleration voltage of 110 kV and an exposure dose of 45 kGy. Then, a heat-sealable film was laminated onto the adhesive composition. The adhesive composition was then aged at 40°C for 72 hours.

[0122] Example 1 A laminate was produced by laminate production method 1 using active energy ray-curable adhesive composition 1 as the active energy ray-curable adhesive composition and film 1 as the film. The peel strength showed good initial adhesion of 0.7 N / 15 mm, and extremely good post-aging adhesion of 4.4 N / 15 mm. The failure mode was also good (A), and the coating film appearance and flexibility were also good. The results are shown in Table 2.

[0123] Examples 2 to 15: Laminates were produced by laminate manufacturing method 1 using active energy ray-curable adhesive compositions 2 to 15 and film 1 as the active energy ray-curable adhesive compositions. In Examples 2 to 15, the peel strength was good both initially and after aging. In Examples 2 to 6, the conjugated diene polymer (A) that was liquid at 25°C and 1 atmosphere contained a (meth)acryloyl group, which allowed it to integrate with the acrylate cured film, tending to improve initial adhesion. In Examples 7 to 10, increasing the amount of the conjugated diene polymer (A) that was liquid at 25°C and 1 atmosphere tended to improve coating film flexibility and initial adhesion. However, because the viscosity of the active energy ray-curable adhesive composition increased and the amounts of the other components, the polyfunctional (meth)acrylate (B), polyol compound (C), and polyisocyanate compound (D), decreased, curability and post-aging adhesion tended to decrease above a certain amount. In Examples 11 to 14, when the compatibility of the polyfunctional (meth)acrylate (B) was poor, the flexibility of the coating film and the initial adhesion tended to decrease. Furthermore, when a polyfunctional (meth)acrylate (B) containing a tertiary amino group was used, the initial adhesion tended to improve. In Example 15, when the amounts of the polyol compound (C) and the polyisocyanate compound (D) were below a certain level, the adhesion after aging decreased. The results are shown in Tables 2 and 3.

[0124] [Examples 16 to 18] Using active energy ray-curable adhesive composition 6 as the active energy ray-curable adhesive composition and films 2 to 4 as the films, laminates were produced by laminate production method 1. Both the coating film appearance and coating film flexibility were good, and the peel strength and initial adhesion were all good, and the adhesion after aging were all extremely good. The results are shown in Table 3.

[0125] [Example 19] A laminate was produced by UV curing using active energy ray-curable adhesive composition 16 as the active energy ray-curable adhesive composition and film 1 as the film according to laminate production method 2. Both the coating film appearance and coating film flexibility were good, and the peel strength showed good initial adhesion and extremely good adhesion after aging. The results are shown in Table 3.

[0126] [Example 20] A laminate was produced by laminate production method 3 using active energy ray-curable adhesive composition 6 as the active energy ray-curable adhesive composition and film 1 as the film. By irradiating with an electron beam before lamination, improvement in initial adhesion due to accelerated curing was observed. The final laminate peel strength was approximately the same as in Example 6, and was an extremely good result. The results are shown in Table 3.

[0127] Comparative Examples 1 to 4: Laminates were produced by laminate manufacturing method 1 using active energy ray-curable adhesive compositions 17 to 20 and film 1 as the active energy ray-curable adhesive compositions. In Comparative Example 1, in which a conjugated diene polymer solid at 25°C and 1 atmosphere was used instead of the conjugated diene polymer (A) liquid at 25°C and 1 atmosphere, the coating film appearance was poor due to non-uniformity of the active energy ray-curable adhesive composition, and the coating film flexibility was inferior to that of Examples 1 to 6 with the same content. Initial adhesion was also insufficient. In Comparative Example 2, which did not contain the polyfunctional (meth)acrylate (B) component, the coating film appearance was insufficient due to the curability and high viscosity. In Comparative Example 3, which did not contain the conjugated diene polymer (A) liquid at 25°C and 1 atmosphere, the coating film flexibility and initial adhesion were insufficient. In Comparative Example 4, which did not contain the polyol compound (C) and polyisocyanate compound (D) components, the adhesion after aging was insufficient. The results are shown in Table 3.

[0128]

[0129]

[0130] [Example 21] A laminate was produced by laminate production method 1 using substrate film 4, heat-sealable film 1, and active energy ray-curable adhesive composition 21. All of the polyolefin layers of this laminate were made of polypropylene resin. The peel strength showed good initial adhesion of 0.5 N / 15 mm, and extremely good post-aging adhesion of 4.3 N / 15 mm. The failure mode was also good (A), and the results of the evaluation of the coating film appearance and coating film flexibility were also good. The results are shown in Table 4.

[0131] [Examples 22 and 23] A laminate was produced by laminate production method 1 using substrate film 4, heat-sealable film 1, and active energy ray-curable adhesive composition 22 (Example 22) or adhesive composition 23 (Example 23). All of the polyolefin layers of this laminate were made of polypropylene resin. In Examples 22 and 23, the initial adhesion was better than in Example 21, and the adhesion after aging was also extremely good. The failure mode was also good (A), and the evaluation results for the coating appearance and coating flexibility were both good. In Example 22, －１ A peak derived from the nitrile group was observed in the range of 1700-1750 cm. －１ The ratio ((C) / (B)) of the maximum peak height (B) in the section (C) to the maximum peak height (B) in the section (C) was 0.30. The results are shown in Table 4.

[0132] Example 24 A laminate was produced by laminate production method 1 using substrate film 5, heat-sealable film 2, and active energy ray-curable adhesive composition 21. All of the polyolefin layers in this laminate were made of polyethylene resin. The peel strength showed good initial adhesion of 0.6 N / 15 mm, and extremely good post-aging adhesion of 4.2 N / 15 mm. The failure mode was also good (A), and the results of the coating appearance and coating flexibility evaluations were also good. The results are shown in Table 4.

[0133] Example 25 A laminate was produced by laminate production method 1 using substrate film 6, heat-sealable film 3, and active energy ray-curable adhesive composition 21. All of the polyolefin layers in this laminate were made of polypropylene resin. The peel strength showed good initial adhesion of 0.6 N / 15 mm, and extremely good post-aging adhesion of 4.4 N / 15 mm. The failure mode was also good (A), and the results of the coating appearance and coating flexibility evaluations were also good. The results are shown in Table 4.

[0134] Example 26 A laminate was produced by laminate production method 1 using substrate film 7, heat-sealable film 2, and active energy ray-curable adhesive composition 21. All of the polyolefin layers in this laminate were made of polyethylene resin. The peel strength showed good initial adhesion of 0.6 N / 15 mm, and extremely good post-aging adhesion of 4.4 N / 15 mm. The failure mode was also good (A), and the coating appearance and flexibility were also good. The results are shown in Table 4.

[0135] [Example 27] A laminate was produced by laminate production method 1 using substrate film 6, heat-sealable film 2, and active energy ray-curable adhesive composition 21. The peel strength showed good initial adhesion of 0.6 N / 15 mm, and the adhesion after aging was also very good at 4.3 N / 15 mm. The failure mode was also good (A), and the results of the evaluation of the coating film appearance and coating film flexibility were also good. The results are shown in Table 4.

[0136] Comparative Example 5 A laminate was produced by laminate production method 1 using base film 4, heat-sealable film 1, and active energy ray-curable adhesive composition 24. All of the polyolefin layers of this laminate were made of polypropylene resin. The peel strength showed insufficient initial adhesion of 0.1 N / 15 mm. The post-aging adhesion was good at 3.4 N / 15 mm. The failure mode was cohesive failure (B), and although the coating appearance was excellent, the coating flexibility was evaluated as poor (C). The results are shown in Table 4.

[0137] [Comparative Example 6] A laminate was produced by laminate production method 1 using base film 4, heat-sealable film 1, and active energy ray-curable adhesive composition 25. All of the polyolefin layers of this laminate were made of polypropylene resin. The peel strength showed an initial adhesion of 0.1 N / 15 mm, which was insufficient. The adhesion after aging was also insufficient, at 2.6 N / 15 mm. The failure mode was peeling at the interface (C), and although the coating appearance was excellent, the coating flexibility was evaluated as poor (C). The results are shown in Table 4.

[0138]

[0139] Furthermore, the laminates of Examples 21 to 27 were stacked with the sides having the heat-sealable films stacked together, and heat-sealed under conditions of 135°C at the top, 80°C at the bottom, 0.1 MPa, and 1 second when the heat-sealable film was CPP, or 105°C at the top, 80°C at the bottom, 0.1 MPa, and 1 second when the heat-sealable film was LLDPE. It was confirmed that the laminates had good heat-sealability suitable for use as packaging materials.

Claims

1. An active energy ray-curable adhesive composition comprising a conjugated diene polymer (A) that is liquid at 25°C and 1 atm, and a polyfunctional (meth)acrylate (B), a polyol compound (C), and a polyisocyanate compound (D), The conjugated diene polymer (A) has a (meth)acryloyl group, The weight-average molecular weight of the conjugated diene polymer (A) is 10,000 or more and 50,000 or less. Active energy ray curable adhesive composition.

2. The active energy ray curable adhesive composition according to claim 1, wherein the polyfunctional (meth)acrylate (B) has a tertiary amino group.

3. The active energy ray curable adhesive composition according to claim 1, wherein the polyfunctional (meth)acrylate (B) is a di(meth)acrylate having an alicyclic skeleton or a di(meth)acrylate having 9 to 18 carbon atoms.

4. The active energy ray curable adhesive composition according to claim 3, wherein the di(meth)acrylate having an alicyclic skeleton is tricyclodecanedimethanol di(meth)acrylate.

5. The active energy ray curable adhesive composition according to claim 1, wherein the glass transition temperature (Tg) of the conjugated diene polymer (A) is -80°C or higher and -20°C or lower.

6. The active energy ray-curable adhesive composition according to claim 1, wherein the conjugated diene polymer (A) is contained in an amount of 5% by mass or more and 30% by mass or less in the active energy ray-curable adhesive composition.

7. The active energy ray-curable adhesive composition according to claim 1, wherein the total content of the polyol compound (C) and the polyisocyanate compound (D) when the mass of the active energy ray-curable adhesive composition is 100% by mass is 50% by mass or more and 80% by mass or less.

8. The active energy ray curable adhesive composition according to claim 1, which is substantially free of solvents and monofunctional (meth)acrylates.

9. A method for manufacturing a laminate, comprising, in this order: a laminating step of bonding the same or different types of films together to form a laminate film via an active energy ray-curable adhesive composition according to any one of claims 1 to 8; an irradiation step of irradiating the laminate film with active energy rays; and an aging step of curing the film irradiated with active energy rays.

10. A method for manufacturing a laminate, comprising the steps of: applying an active energy ray-curable adhesive composition according to any one of claims 1 to 8 to a film; irradiating the film coated with the adhesive composition with active energy rays; laminating and bonding the same or different type of film to the side of the film irradiated with active energy rays where the adhesive composition was applied to form a laminate film; and aging the laminated film in this order.

11. The method for manufacturing a laminate according to claim 9, wherein the active energy ray is an electron beam.

12. The method for manufacturing a laminate according to claim 10, wherein the active energy ray is an electron beam.

13. A laminate comprising at least a first resin layer mainly composed of resin, a second resin layer mainly composed of polyolefin as a resin component, and a layer mainly composed of resin existing between the first and second resin layers (referred to as the "first intermediate layer"), wherein the second resin layer has a lower melting point than the first resin layer, and the first intermediate layer contains at least polyurethane, a compound having an aliphatic carbon-carbon double bond, and poly(meth)acrylate, and the laminate shows a range of 1600 to 1650 cm in transmission infrared spectroscopy observations. －１ The maximum peak height (A) in this section is 1700-1750 cm. －１ A laminate in which the ratio ((A) / (B)) of the maximum peak height (B) in the interval is 0.05 or more and 0.40 or less.

14. The laminate according to claim 13, wherein the first resin layer is mainly composed of polyolefin.

15. The laminate according to claim 13, wherein the compound having an aliphatic carbon-carbon double bond is a conjugated diene polymer.

16. The laminate according to claim 13, wherein the first resin layer has ink printing on at least one of its surfaces.

17. A packaging material using a laminate according to any one of claims 13 to 16, wherein the packaging material is formed by bonding in the second resin layer.