Laminate and method for manufacturing a laminate

Abstract

To provide a laminate having a digitally printed layer that is excellent in gloss, alcohol resistance, abrasion resistance, and low odor. [Solution] A laminate comprising a substrate, a printed layer, and an overcoat layer in this order, wherein the printed layer is a printed layer produced by a digital printing method, the overcoat layer is a layer obtained by curing an electron beam of an electron beam-curable composition containing a (meth)acrylate compound, the electron beam-curable composition substantially does not contain a photopolymerization initiator, the overcoat layer has a protruding valley height Svk of 0.8 μm or less as defined in ISO 25178, and a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to laminates and methods for manufacturing laminates. [Background technology]

[0002] In the traditional printing industry, systems requiring platemaking processes, such as gravure printing, offset printing, and flexographic printing, were dominant for printing large batches of the same design. However, in recent years, there has been an increasing demand for small-batch printing (variable data printing) for a wide variety of designs, as well as a need for shorter delivery times, while the demand for large-batch printing has decreased. In this environment, digital printing, which does not require platemaking processes, is seeing increased use as a means to achieve variable data printing and shorter delivery times.

[0003] Meanwhile, in the printing industry, from the perspective of reducing environmental impact, the replacement of lamination configurations used for reverse printing with configurations used for front printing is being considered. In the laminate configuration of reverse printing, multiple films are bonded together with adhesive to form a film layer, thereby providing the protective function required by the contents. In such a configuration, the printed surface is sandwiched between film layers, and the film is the outermost surface, so physical properties such as strength are not required of the ink coating. In contrast, in the laminate of front printing, the ink coating is the outermost surface, so an overcoat is generally applied to protect the ink coating.

[0004] Overcoats require various physical properties depending on their intended use. Typical examples include abrasion resistance (strength against rubbing), gloss (which affects attractiveness), and resistance to alcohol used for disinfection and sterilization.

[0005] Due to the characteristics of the raw materials, printed materials produced by digital printing have weak abrasion resistance, gloss, and alcohol resistance. Even when the surface is protected with conventional solvent- or water-based heat-drying overcoats, it is difficult to achieve practically sufficient levels of these properties. Therefore, digital printing is difficult to apply to front-facing printing, and its use as a lamination structure for back-facing printing is the mainstream. As a result, the use of active energy ray-curable overcoats with strong coating properties is attracting attention as a way to apply digital printing to front-facing printing.

[0006] In recent years, the use of curing technology using active energy rays has been expanding in the printing industry due to its advantages in shortening process time through instant drying, reducing environmental impact and improving work safety by eliminating volatile organic compounds (VOCs), and achieving strong coating properties through cross-linking reactions.

[0007] The use of active energy ray curing technology, which began in the commercial printing field based on paper substrates such as flyers and posters, has expanded to various application fields thanks to advancements in printing technology, including printing presses and inks. It is now being applied to various film substrates, and its use is expanding to packaging materials and containers for food, cosmetics, and toys, as well as labels, card games, and other applications.

[0008] While UV-curing overcoats are the mainstream among active energy ray-curing overcoats, they contain a considerable amount of photoinitiators, which act as inert components and affect the strength of the cured coating. Furthermore, in the case of packaging materials, there are concerns about odors derived from unreacted or decomposed photoinitiators and their potential health effects. In addition, with UV curing, damage to the substrate due to the heat generated by the UV lamp is also a problem. Moreover, in order to improve adhesion and leveling on digital printing surfaces, inert resins are sometimes applied to UV-curing overcoats, but while inert resins improve adhesion and leveling, they significantly reduce alcohol resistance and abrasion resistance, which is a challenge.

[0009] Against this backdrop, electron beam (EB) curing overcoats are attracting attention as an alternative to ultraviolet (UV) curing overcoats, as they do not require photopolymerization initiators, cause less thermal damage to the substrate, and have good adhesion to digital printing surfaces.

[0010] The raw materials that make up electron beam (EB) curable overcoats are largely the same as those used in ultraviolet (UV) curable overcoats, except that they do not require an initiator. Many of the common main raw materials, (meth)acrylate compounds, have high surface tension on digital printing surfaces. Therefore, poor leveling on digital printing surfaces is one of the factors contributing to reduced gloss. Leveling is not limited to electron beam (EB) curable overcoats; it is a common challenge for all active energy ray curable overcoats, and further improvement is needed.

[0011] Various attempts have been made to address the challenges of realizing this type of surface printing in digital printing.

[0012] Patent Document 1 discloses a technology that uses an active energy ray-curable overcoat varnish containing an amino group-containing styrene (meth)acrylic resin, a cyclic-structured 2-3 functional (meth)acrylate monomer, and a 2-4 functional (meth)acrylate monomer to achieve excellent adhesion, gloss, low curling, and high curability to a substrate and an ink layer.

[0013] Patent Document 2 discloses a printing coating agent containing polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, and rosin-modified maleic acid resin, which exhibits various physical properties such as scratch resistance, tape adhesion resistance, heat resistance, and gloss, as well as blocking resistance to PVC sheets.

[0014] In Patent Document 3, a technique is disclosed in which by irradiating an electron beam onto a polymer ink containing a polyolefin-based binder, at least a part of the polymerink is crosslinked, and the heat resistance and pressure resistance of the polymer ink can be improved. It is also disclosed that the same effect can be obtained even when an EB-curable lacquer is applied.

[0015] However, in the above invention, it is difficult to obtain a laminate including a digital printing layer that satisfies all of the glossiness, coating film resistance such as alcohol resistance and abrasion resistance, and low odor property, and further study is desired.

Prior Art Documents

Patent Documents

[0016]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0017] The problem to be solved by the present invention is to provide a laminate having a digital printing layer that is excellent in glossiness, coating film resistance such as alcohol resistance and abrasion resistance, and low odor property.

Means for Solving the Problems

[0018] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following laminate, and have completed the present invention.

[0019] That is, embodiments of the present invention relate to the following. However, the present invention is not limited to the following embodiments and includes various embodiments. <1> A laminate having a substrate, a printed layer, and an overcoat layer in this order, The aforementioned printing layer is a printing layer produced by a digital printing method. The overcoat layer is a layer made of a cured product of an electron beam curable composition containing a (meth)acrylate compound. The electron beam curable composition substantially does not contain a photopolymerization initiator. A laminate in which the overcoat layer has a protruding valley height Svk of 0.8 μm or less as defined in ISO 25178, and a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577.

[0020] <2> The viscosity of the electron beam curable composition measured by an E-type viscometer (25°C, 100 rpm) is 1200 mPa·s or less, as described above. <1> The laminate described above.

[0021] <3> The amount of electron beam-curable composition applied to the overcoat layer is 2 g / m². 2 More than 5g / m 2 The following is the above <1> or <2> The laminate described above.

[0022] <4> The (meth)acrylate compound includes a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit. <1> ~ <3> The laminate described in any of the following.

[0023] <5> The above-mentioned (meth)acrylate compound having two or more (meth)acryloyl groups in its molecule and having propylene oxide as a constituent unit, has a content of 5 to 98% by mass of the total amount of the electron beam curable composition. <4> The laminate described above.

[0024] <6> The above includes a compound having two or more (meth)acryloyl groups in the molecule and propylene oxide as a constituent unit, wherein when the number of (meth)acryloyl groups in the molecule is X, the compound contains X to 3X propylene oxide as a constituent unit in the molecule. <4> or <5> The laminate described above.

[0025] <7> the above <1> ~ <6> A packaging material consisting of one of the laminates described above.

[0026] <8> the above <1> ~ <6> A seal label consisting of the laminate described in one of the following.

[0027] <9> the above <1> ~ <6> A method for manufacturing a laminate as described in any of the following: A process for manufacturing a printed layer on a substrate using digital printing, A process of manufacturing an overcoat layer by applying an electron beam-curable composition onto a printed layer and irradiating it with an electron beam under conditions of an acceleration voltage of 50 to 200 kV and an irradiation dose of 15 to 60 kGy, A method for manufacturing a laminate, including the following: [Effects of the Invention]

[0028] The present invention provides a laminate having a digitally printed layer that is excellent in gloss, coating film resistance such as alcohol resistance and abrasion resistance, and low odor. [Modes for carrying out the invention]

[0029] The embodiments for carrying out the present invention will be described in detail below. However, the present invention is not limited to the following embodiments and can be implemented in various ways within the scope of its gist.

[0030] The following terms used in this specification are explained. "(meth)acryloyl" means acryloyl and / or methacryloyl (methacryloyl), and "(meth)acrylate" means acrylate and / or methacrylate (methacrylate). In addition, "PO" represents "propylene oxide" and "EO" represents "ethylene oxide".

[0031] <Laminate> One embodiment of the present invention relates to a laminate having a substrate, a printed layer by a digital printing method, and an overcoat layer in that order, wherein the overcoat layer is composed of a cured product of an electron beam curable composition containing a (meth)acrylate compound, and has a protruding valley height Svk of 0.8 μm or less as defined in ISO 25178, and a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577. The electron beam curable composition substantially does not contain a photopolymerization initiator and can be cured by electron beam irradiation.

[0032] The laminate of this embodiment can be used for various applications. In particular, it can be suitably used as a packaging material and a seal label. The structure of the laminate will be described in more detail below.

[0033] <Base material> The substrate in the laminate of this embodiment is not particularly limited and known substrates can be used, but film substrates and paper substrates are preferred. Examples include polyolefin substrates such as polyethylene and polypropylene, synthetic paper such as Yupo paper made from polypropylene and inorganic fillers, polyester substrates such as polyethylene terephthalate and polylactic acid, polycarbonate substrates, polystyrene-based substrates such as polystyrene, AS resin, and ABS resin, nylon substrates, polyamide substrates, polyvinyl chloride substrates, polyvinylidene chloride substrates, cellophane substrates, paper substrates, aluminum substrates, or film substrates made from composite materials thereof. Among these, polyolefin-based films are preferred from the viewpoint of recyclability. Furthermore, a vapor-deposited substrate can be used, which is obtained by vapor-depositing inorganic compounds such as silica, alumina, and aluminum onto a film substrate. In addition, the vapor-deposited surface may be coated with polyvinyl alcohol or the like. The substrate is preferably treated for easy adhesion on the surface to be printed (the surface in contact with the printed layer). Specific examples of easy adhesion treatments include corona discharge treatment, ultraviolet / ozone treatment, plasma treatment, oxygen plasma treatment, and primer treatment. In addition, if sufficient adhesion cannot be obtained with a polyethylene terephthalate substrate, surface treatments such as acrylic coating, polyester treatment, polyurethane treatment, and polyvinylidene chloride treatment may be applied.

[0034] The paper substrate can be ordinary paper or corrugated cardboard, and there are no particular limitations on the film thickness. The printed surface may be treated for easy adhesion. The paper substrate may have its surface vapor-deposited with a metal such as aluminum for the purpose of adding design appeal. Furthermore, the paper substrate may be surface-coated with acrylic resin, urethane resin, polyester resin, polyolefin resin, or other resins, and may also be surface-treated with corona treatment or other methods. For example, specific examples of surface-treated paper substrates include coated paper and art paper.

[0035] A laminate having a heat-seal layer may be used as the base material. A laminate having a heat-seal layer is preferably a laminate of a film or paper base material and a heat-sealable film. There are no particular restrictions on the heat-sealable film; known films can be used. Examples include low-density polyethylene (LDPE), polyethylene such as linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, copolymerized polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-(meth)acrylic acid copolymer, and polyolefin resins such as ionomers. Among these, polypropylene resins are preferred from the viewpoint of recyclability, and unstretched polypropylene is particularly preferred from the viewpoint of heat-sealability. The thickness of the heat seal layer is not particularly limited, but considering the processability and heat sealability of the laminate, it is preferably in the range of 10 to 60 μm, and more preferably in the range of 15 to 40 μm. The method for laminating the heat seal layer is not particularly limited. For example, methods include laminating the substrate and sealant film by heat (thermal lamination, dry lamination), or melting the sealant resin, extruding it onto the substrate, and then cooling and solidifying it to create a laminate (extrusion lamination method). Additionally, a heat sealant can be applied as a heat seal layer.

[0036] A sticker label may be used as the base material. There are no particular restrictions on the sticker label, and any known type can be used. A film or paper base material is preferred as the surface base material of the sticker label. Preferred surface base materials for films are polyester film, polyvinyl chloride film, synthetic paper, polypropylene film, polyethylene film, polystyrene film, and ABS film. Preferred surface base materials for paper are fine paper, art paper, coated paper, gloss paper, foil paper, and specialty paper. There are no particular restrictions on the film thickness. The printed surface may be treated for easy adhesion.

[0037] <Print layer> The printed layer in the laminate of this embodiment is a printed layer produced by a digital printing method, and is not particularly limited; it can be arbitrarily selected from known methods. Examples of digital printing methods include wet (liquid toner) electrophotography, dry (powder toner) electrophotography, and inkjet methods (UV curing type, aqueous type, solvent type). In a preferred embodiment, printing is performed using an Indigo® digital printing press manufactured by Hewlett-Packard. Furthermore, it is preferable that the printed layer is printed by electrophotographic printing using an electrostatic ink containing at least a colorant, a thermoplastic polymer, a charge director, and a liquid carrier.

[0038] <Overcoat layer> The overcoat layer in the laminate of this embodiment is a layer obtained by curing an electron beam-curable composition containing a (meth)acrylate compound with an electron beam. In this specification, a (meth)acrylate compound means a compound having a (meth)acryloyl group in its molecule.

[0039] In the laminate of this embodiment, the electron beam curable composition constituting the overcoat layer is not particularly limited, and only needs to satisfy the requirements of the desired protruding valley height Svk and hardness of the cured coating film. Although not particularly limited, the electron beam curable compositions described later can be suitably used.

[0040] (Overcoat layer protruding valley height Svk) In the laminate of this embodiment, the overcoat layer has a protruding valley height Svk of 0.8 μm or less (or 0) as defined in ISO 25178. Preferably, the protruding valley height Svk of the overcoat layer is 0.5 μm or less (or 0). The protruding valley height (Svk) is a three-dimensional surface roughness value compliant with ISO 25178, and is one of the functional parameters (Functions and related parameters) using a load curve (Material Ratio Curve). The core is the surface obtained by removing the area not included in the height range of the load area ratio from 0% to 100% of the equivalent straight line. The portion that is indented below the core in the load curve is called the protruding valley, and its average depth is Svk. The protruding valley also represents the area where liquid applied to the surface to improve lubricity accumulates. The smaller the value of the protruding valley height (Svk), the higher the smoothness of the overcoat layer, resulting in a better appearance.

[0041] The measurement method for the height Svk of the protruding valleys in the overcoat layer is as follows: The surface of the overcoat layer was measured using a laser microscope VK-X3000 (manufactured by Keyence Corporation) equipped with a white light interferometer. The measurement conditions were white light interferometry scan mode and objective lens magnification of 10x. The image processing conditions were a 5 μm S-filter, a 0.8 mm L-filter, no F-operation, termination effect correction enabled, and an evaluation area of ​​1406 μm × 1055 μm (entire area specified).

[0042] (Hardness of the overcoat layer) The overcoat layer in the laminate of this embodiment has a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577. Preferably, the hardness of the overcoat layer is 70 to 150 MPa. Nanoindentation hardness is the value of indentation hardness measured using a micro-area mechanical property evaluation device (nanomidentifier), and is defined in ISO 14577. In this specification, the value is measured using a Hyzitron TI Premier (manufactured by Bruker). Because the nanoindenter indents only the very surface layer of the laminate, it is unaffected by the substrate and can measure the mechanical properties of only the thin overcoat layer. In other measurement methods, the indentation load and displacement are too large, making it difficult to measure only the thin layer. In this specification, the hardness of only the overcoat layer is indicated.

[0043] The method for measuring nanoindentation hardness (H) is as follows: A triangular pyramidal Berkovich indenter is used as the indenter for the nanoindenter. The Berkovich indenter is pressed into the sample under the indentation conditions described below, and the indentation depth h (nm) for each indentation load F (μN) is continuously measured to create a load-displacement curve. The maximum indentation load Fmax (μN) is determined from the created load-displacement curve. Then, the maximum indentation load Fmax (μN) is calculated by multiplying it by the contact projected area Ac (μm²) between the indenter and the sample at that time. 2 The hardness is determined by dividing by ). That is, H = Fmax / Ac. Here, Ac is the contact projection area obtained by correcting the indenter tip curvature using the instrument's standard method with fused silica as the standard sample. The contact projection area Ac is calculated from the contact depth h (nm), and for an ideal Berkovich indenter, Ac = 24.56h 2 That is the case. The measurement was performed at 25°C, by indenting the indenter to a depth of 150 nm over 5 seconds and holding it at a depth of 150 nm for 2 seconds. The load obtained at this depth was defined as the maximum indentation load Fmax (μN). Subsequently, the load was removed over 5 seconds until the depth reached 0 nm, and a load-displacement curve was obtained.

[0044] To reduce the protruding valley height Svk to 0.8 μm or less, it is effective to improve the leveling properties of the electron beam curable composition that forms the overcoat layer. Means of improving leveling properties include lowering the viscosity of the electron beam curable composition, lowering the surface tension of the electron beam curable composition, and adjusting the film thickness of the coating. In particular, using a low-viscosity (meth)acrylate compound, which is the main component of the electron beam curable composition, greatly improves leveling properties. However, low-viscosity (meth)acrylate compounds tend to have a small number of (meth)acryloyl groups and a small concentration of (meth)acryloyl groups, which tends to result in lower hardness of the cured coating, making it difficult to set the nanoindentation hardness within a specific range. On the other hand, to achieve a nanoindentation hardness of 50-200 MPa, it is effective to increase the crosslinking density of the cured coating film. Methods for increasing the crosslinking density of the cured coating film include increasing the concentration of (meth)acryloyl groups in the electron beam curable composition and optimizing the electron beam irradiation dose. In particular, using a large number of (meth)acryloyl groups or a high concentration of (meth)acryloyl groups as the main component of the electron beam curable composition leads to a higher crosslinking density of the cured coating film. However, (meth)acrylate compounds with a high number of (meth)acryloyl groups or a high concentration of (meth)acryloyl groups tend to have high viscosity and low leveling properties, making it difficult to set the protruding valley height Svk within a specific range.

[0045] In the laminate of this embodiment, the overcoat layer is characterized by having a protruding valley height Svk of 0.8 μm or less as defined in ISO 25178, and a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577. By having the above requirements for protruding valley height Svk and nanoindentation hardness fall within the above ranges, the laminate is made which has excellent gloss and excellent coating film resistance such as alcohol resistance and abrasion resistance.

[0046] <Electron beam curable composition> One embodiment of the present invention relates to an electron beam curable composition that can be suitably used as a material for forming an overcoat layer in the laminate of the above embodiment.

[0047] The electron beam curable composition of this embodiment contains a (meth)acrylate compound. In this specification, a (meth)acrylate compound means a compound having a (meth)acryloyl group in its molecule.

[0048] Specific examples of (meth)acrylate compounds that can be used to constitute the electron beam curable composition in this embodiment 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, 3,3,5-Trimethylethyl Monofunctional (meth)acrylate compounds such as chlorohexanol (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (oxyethyl) (meth)acrylate, 1,4-cyclohexanedimethanol (meth)acrylate, cyclic trimethylolpropaneformal (meth)acrylate, benzyl (meth)acrylate, EO (2 molar) modified nonylphenol acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, acryloylmorpholine, and 2-(2-vinyloxyethoxy)ethyl acrylate. 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, Polyethylene glycol (400) di(meth)acrylate, Polyethylene glycol (600) di(meth)acrylate, Neopentyl glycol di(meth)acrylate, Hydroxypivalate Neo Difunctional (meth)acrylate compounds such as pentyl glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, EO (2 mol) modified 1,6-hexanediol di(meth)acrylate, PO (2 mol) modified neopentyl glycol di(meth)acrylate, (neopentyl glycol modified) trimethylolpropane di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, EO (4 mol) modified bisphenol A di(meth)acrylate, PO (4 mol) modified bisphenol A di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and dicyclopentanyl di(meth)acrylate. Trifunctional (meth)acrylate compounds such as trimethylolpropane tri(meth)acrylate, EO (3 mol) modified trimethylolpropane tri(meth)acrylate, EO (6 mol) modified trimethylolpropane tri(meth)acrylate, EO (9 mol) modified trimethylolpropane tri(meth)acrylate, PO (3 mol) modified trimethylolpropane tri(meth)acrylate, PO (6 mol) modified trimethylolpropane tri(meth)acrylate, PO (9 mol) modified trimethylolpropane tri(meth)acrylate, ε-caprolactone modified tris-(2-acryloxyethyl) isocyanurate, ethoxylated isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerin propoxy tri(meth)acrylate, Tetrafunctional (meth)acrylate compounds such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, EO (4 molar) modified pentaerythritol tetra(meth)acrylate, PO (4 molar) modified pentaerythritol tetra(meth)acrylate, EO (4 molar) modified ditrimethylolpropane tetra(meth)acrylate, and PO (4 molar) modified ditrimethylolpropane tetra(meth)acrylate. Pentafunctional (meth)acrylate compounds such as dipentaerythritol penta(meth)acrylate, EO (5 molar) modified dipentaerythritol penta(meth)acrylate, and PO (5 molar) modified dipentaerythritol penta(meth)acrylate. Examples include hexafunctional (meth)acrylate compounds such as dipentaerythritol hexa(meth)acrylate, EO (6 molar)-modified dipentaerythritol hexa(meth)acrylate, and PO (6 molar)-modified dipentaerythritol hexa(meth)acrylate. Furthermore, the (meth)acrylate compound may be a mono- or polyalkylene oxide modified compound other than those mentioned above.

[0049] Furthermore, as (meth)acrylate compounds, urethane (meth)acrylates such as aliphatic urethane (meth)acrylate and aromatic urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, epoxy (meth)acrylate, etc. can be used.

[0050] <Epoxy (meth)acrylate> Epoxy (meth)acrylate may be, for example, an epoxy (meth)acrylate obtained by reacting a glycidyl group contained in an epoxy resin with (meth)acrylic acid having a carboxyl group. Other examples include epoxy (meth)acrylate obtained by reacting a resin having an acidic group such as a carboxyl group with a (meth)acrylate compound having a glycidyl group, both of which have unsaturated double bond groups. For example, in the former case, examples include epoxy (meth)acrylate obtained by adding (meth)acrylic acid to a bisphenol A type epoxy resin, and epoxy (meth)acrylate obtained by adding (meth)acrylic acid to a novolac type epoxy resin.

[0051] <Urethane (meth)acrylate> Examples of urethane (meth)acrylates include urethane (meth)acrylates obtained by reacting a polyisocyanate with a hydroxyl group-containing (meth)acrylate, urethane (meth)acrylates obtained by reacting an isocyanate group-containing urethane prepolymer, which is obtained by reacting a polyol with a polyisocyanate under conditions of excess isocyanate groups, with a hydroxyl group-containing (meth)acrylate, or urethane (meth)acrylates obtained by reacting a hydroxyl group-containing urethane prepolymer, which is obtained by reacting a polyol with a polyisocyanate under conditions of excess hydroxyl groups, with (meth)acrylates having isocyanate groups.

[0052] Known polyisocyanates can be used as described above, including aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. For example, aromatic diisocyanates include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyli isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenedi isocyanate, m-tetramethylxylylene diisocyanate, 1,4-phenylenedi isocyanate, and tolylene diisocyanate. Examples of aliphatic diisocyanates include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. Examples of alicyclic diisocyanates include cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, and dimer isocyanates obtained by modifying the carboxyl groups of dimer acids with isocyanate groups. Among these, aromatic diisocyanates and / or alicyclic diisocyanates are preferred. Preferred examples of the above-mentioned compounds include tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isocyanurates of hexamethylene diisocyanate.

[0053] <Polyester (meth)acrylate> In this embodiment, polyester (meth)acrylates are obtained by polycondensation of a polybasic acid and a polyhydric alcohol using known methods, and the molecular weight and the amount of terminal groups such as hydroxyl groups or carboxyl groups are adjusted by the mixing ratio of carboxyl groups and hydroxyl groups. For example, if the amount of carboxyl groups in a polybasic acid is greater than the amount of hydroxyl groups in a polyhydric alcohol, the terminal functional group will be a carboxyl group. By condensing this with the hydroxyl groups of a hydroxyl-containing (meth)acrylate, the desired polyester (meth)acrylate can be obtained.

[0054] Examples of the above polybasic acids include aliphatic, alicyclic, and aromatic types, and there are no particular restrictions on their use. For example, aliphatic polybasic acids include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, suberic acid, maleic acid, chloromaleic acid, fumaric acid, dodecanediic acid, pimelic acid, citraconic acid, glutaric acid, itaconic acid, succinic anhydride, maleic anhydride, fatty acids, and dimer acids derived from fatty acids, and these aliphatic dicarboxylic acids and their anhydrides can be used. Among these, polyester acrylates having structural units derived from at least one polybasic acid selected from adipic acid, succinic acid, azelaic acid, sebacic acid, fatty acids, modified fatty acids, and dimer acids derived from fatty acids are preferred.

[0055] Furthermore, examples of the above polyhydric alcohols include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 3,3'-dimethylolheptane, 2-butyl-2-ethyl-1,3-propanediol, polyoxyethylene glycol (additional moles of 10 or less), polyoxypropylene glycol (additional moles of 10 or less), propanediol, 1,3-butanediol, and 1,4-butane. Preferred examples include bifunctional aliphatic or alicyclic alcohols such as diols, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, cyclohexanedimethanol, tricyclodecanedimethanol, cyclopentadienedimethanol, and dimergol, as well as trifunctional aliphatic or alicyclic alcohols such as glycerin, trimethylolpropane, 1,2,4-butanetriol and their ethylene oxide adducts (number of added moles 10 or less) or propylene oxide adducts (number of added moles 10 or less). In particular, it is preferable to have a structural unit derived from at least one compound selected from the group consisting of ethylene glycol, propylene glycol, glycerin, and trimethylolpropane.

[0056] Furthermore, the above-mentioned hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, 10-hydroxydecyl (meth)acrylate, and other hydroxyl group-containing mono(meth)acrylates. Hydroxyl group-containing di(meth)acrylates such as glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate, and 2-hydroxy-3-acryloyloxypropyl(meth)acrylate. Hydroxyl group-containing tri(meth)acrylates such as pentaerythritol tri(meth)acrylate, and Dipentaerythritol penta(meth)acrylate and other hydroxyl group-containing penta(meth)acrylates, Examples include the hydroxyl group-containing (meth)acrylates mentioned above, (meth)acrylates having a hydroxyl group at the terminal by ring-opening addition of ε-caprolactone, and alkylene oxide-added (meth)acrylates obtained by repeatedly adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to the hydroxyl group-containing (meth)acrylates. In particular, a hydroxyl group-containing (meth)acrylate having 1 to 3 (meth)acrylate groups in the molecule is preferred.

[0057] In one embodiment, commercially available polyester (meth)acrylate, urethane (meth)acrylate, and epoxy (meth)acrylate can also be used. For example, Daicel Ornex's EBECRYL 820, 824, 837, and 450 (all polyester acrylates), Daicel Ornex's EBECRYL 8210 and 8409 (both aliphatic urethane acrylates) as urethane (meth)acrylates, and MIWON's MIRAMER PE2160 (both epoxy acrylates) as epoxy (meth)acrylates can be used.

[0058] (Meth)acrylate compounds may be used alone or in combination of two or more types.

[0059] In this embodiment, the (meth)acrylate compound is preferably a polyfunctional acrylate having two or more (meth)acryloyl groups in its molecule, from the viewpoint of curability.

[0060] In this embodiment, it is preferable that the (meth)acrylate compound includes a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit. Since the (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit has low surface tension, it suppresses repulsion during coating, reduces the height of protruding valleys, and contributes to improved gloss. Furthermore, since a high crosslinking density is obtained after curing, the nanoindentation hardness is increased, contributing to improved alcohol resistance and abrasion resistance.

[0061] The content of a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and propylene oxide as a constituent unit is preferably 5 to 98% by mass, more preferably 15 to 97% by mass, and particularly preferably 30 to 97% by mass, of the total amount of the electron beam curable composition.

[0062] Specific examples of (meth)acrylate compounds having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit include (meth)acrylate compounds having propylene oxide as a constituent unit, as mentioned above.

[0063] In a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and propylene oxide as a constituent unit, the number of (meth)acryloyl groups is preferably 2 to 6, more preferably 2 to 4, and particularly preferably 3, in order to balance gloss and hardness.

[0064] In a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and propylene oxide as a constituent unit, the amount of propylene oxide is preferably such that, when the number of (meth)acryloyl groups in the molecule is X, the molecule contains X to 3X propylene oxide as a constituent unit, and more preferably X to 2X, in order to balance gloss and hardness.

[0065] A (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit, wherein when the number of (meth)acryloyl groups in the molecule is X, the (meth)acrylate compound containing X to 2X propylene oxide as a constituent unit in the molecule preferably includes at least one selected from the group consisting of tripropylene glycol di(meth)acrylate, PO(3mol)-modified trimethylolpropane triacrylate, PO(3mol)-modified glyceryl tri(meth)acrylate, PO(4mol)-modified pentaerythritol tetra(meth)acrylate, PO(4mol)-modified ditrimethylolpropane tetra(meth)acrylate, and PO(6mol)-modified dipentaerythritol hexa(meth)acrylate. Suitable commercially available products include TPGDA (tripropylene glycol diacrylate) from Daicel Ornex, Etermer EM 2381 (PO(3 mol) modified trimethylolpropane triacrylate) from Eternal Materials, OTA-480 (PO(3 mol) modified glyceryl tri(meth)acrylate) from Daicel Ornex, ATM-4P (PO(4 mol) modified pentaerythritol tetraacrylate) and A-DPA-6PA (PO(6 mol) modified dipentaerythritol hexaacrylate) from Shin Nakamura Chemical Industry Co., Ltd.

[0066] The electron beam curable composition in this embodiment may further include an extender pigment, resin fine particles, and a leveling agent.

[0067] <Body pigments> In this embodiment, the electron beam curable composition preferably further contains an extender pigment. Including an extender pigment increases the film-forming properties of the coating and improves the strength of the coating. Specific examples of extender pigments include silica, barium sulfate, alumina white, calcium carbonate, magnesium carbonate, aluminum silicate, magnesium silicate, silicon dioxide, and aluminum hydroxide. These may be used individually or in combination of two or more. Silica is preferred as the extender pigment. The extender pigment content is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass, of the total amount of the electron beam curable composition.

[0068] <Resin fine particles> The electron beam curable composition in this embodiment preferably further contains resin fine particles. The inclusion of resin fine particles improves abrasion resistance.

[0069] Specific examples of resin microparticles include urethane resin microparticles, acrylic resin microparticles, acrylic-styrene copolymer resin microparticles, polycarbonate resin microparticles, polyethylene resin microparticles, polystyrene resin microparticles, silicone resin microparticles, melamine resin microparticles, melamine-benzoguanamine resin microparticles, melamine-benzoguanamine-formaldehyde resin (condensate) microparticles, polypropylene resin microparticles, amide resin microparticles, polytetrafluoroethylene resin microparticles, and benzoguanamine resin microparticles. These may be used individually or in combination of two or more types as needed.

[0070] From the viewpoint of abrasion resistance and gloss, the content of resin fine particles is preferably 0.1 to 5% by mass, and more preferably 0.25 to 3% by mass, based on the total mass of the electron beam curable composition.

[0071] Resin microparticles may be obtained commercially or manufactured by known manufacturing methods. For example, specific examples of urethane resin microparticles include Art Pearl C-1000 transparent, Art Pearl C-600 transparent, Art Pearl C-400 transparent, Art Pearl C-800, and Art Pearl MM-120T, all manufactured by Negami Kogyo Co., Ltd. Furthermore, urethane resin microparticles may have a cross-linked structure. Specific examples of urethane resin microparticles having a cross-linked structure include cross-linked urethane resin microparticles such as Art Pearl JB-800T, Art Pearl JB-600T, Art Pearl P-800T, and Art Pearl P-400T, all manufactured by Negami Kogyo Co., Ltd.

[0072] Examples of acrylic resin fine particles include Art Pearl J4PY and Art Pearl J5PY from Negami Kogyo Co., Ltd., and Gantz Pearl GB08S from Aica Kogyo Co., Ltd. Other examples include Epostor MA1002, Epostor MA1004, Epostor MA1006, and Epostor MA1010 from Nippon Shokubai Co., Ltd., Toughtick FH-S005, Toughtick FH-S008, Toughtick FH-S010, Toughtick FH-S015, Toughtick FH-S020 from Toyobo Co., Ltd., and Chemisnow MX-80H3wT, MX-150, MX-180TA, MX-300, MX-500, MX-1000, MX-1500H, MX-2000, and MX-3000 from Soken Chemical Co., Ltd.

[0073] Specific examples of acrylic-styrene copolymer resin fine particles include Epostor MA2003 manufactured by Nippon Shokubai Co., Ltd., and FS-102, FS-201, FS-301, MG-451, and MG-351 manufactured by Nippon Paint Industrial Coatings Co., Ltd.

[0074] Specific examples of polycarbonate resin fine particles include the fine particles described in Japanese Patent Publication No. 2014-125495, the fine particles obtained by the manufacturing method described in Japanese Patent Publication No. 2011-26471, and the fine particles obtained by the method described in Japanese Patent Publication No. 2001-213970.

[0075] Specific examples of silicone resin microparticles include KMP-594, KMP-597, KMP-598, KMP-600, KMP-601, and KMP-602 from Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Co., Ltd.'s Torefil E-506S and EP-9215, and Momentive's Tospearl series.

[0076] Specific examples of polyethylene resin microparticles include Mipelon XM-220 and XM221U manufactured by Mitsui Chemicals, Inc., Flowbeads LE-1080 manufactured by Sumitomo Seika Co., Ltd., and Cerafloure991 manufactured by BIC Chemie Japan Co., Ltd.

[0077] Specific examples of polystyrene-based fine particles include Chemisnow SX-130H, SX-350H, and SX-500H manufactured by Soken Chemical Co., Ltd.

[0078] Specific examples of melamine resin fine particles include Epostor SS, Epostor S, Epostor FS, Epostor S6, and Epostor S12, all manufactured by Nippon Shokubai Co., Ltd.

[0079] A specific example of melamine-benzoguanamine resin microparticles is Epostor M30 manufactured by Nippon Shokubai Co., Ltd.

[0080] Specific examples of benzoguanamine resin microparticles include Epostor MS, Epostor M05, and Epostor L15, manufactured by Nippon Shokubai Co., Ltd.

[0081] Specific examples of polytetrafluoroethylene resin fine particles include SST-3H-RC from Shamrock Technologies.

[0082] The resin fine particles are preferably one or more selected from the group consisting of silicone resin fine particles, acrylic resin fine particles, polytetrafluoroethylene resin fine particles, and polyethylene resin fine particles, and more preferably one or more selected from the group consisting of acrylic resin fine particles and polytetrafluoroethylene fine particles. When using silicone resin microparticles, acrylic resin microparticles, or polyethylene resin microparticles, particle size control is easy, high sphericity, and excellent dispersibility can be easily obtained. Furthermore, these resin microparticles offer high transparency and good slip properties while minimizing gloss reduction. When using polytetrafluoroethylene resin microparticles, excellent heat resistance and slip properties can be obtained due to their chemical stability, high melting point, and low coefficient of friction.

[0083] From the viewpoint of abrasion resistance and gloss, it is preferable to use resin fine particles with an average particle diameter of 1 to 10 μm, and more preferably 2 to 6 μm. The resin microparticles may be in the form of particles composed of various resins, or particles whose surfaces are coated with various resins. Furthermore, the resin microparticles may be used individually or in combination of two or more types.

[0084] <Leveling agent> The electron beam curable composition in this embodiment preferably further contains a leveling agent. The inclusion of a leveling agent improves abrasion resistance and gloss. From the viewpoint of surface lubricity, the leveling agent preferably contains a silicone-modified acrylate compound. The leveling agent may be used alone or in combination of two or more types. The leveling agent content is preferably 0.1 to 3% by mass, and more preferably 0.4 to 1.5% by mass, of the total amount of the electron beam curable composition.

[0085] <Other ingredients> In this embodiment, the electron beam curable composition may contain resins, antistatic agents, surfactants, defoaming agents, ultraviolet absorbers, antioxidants, curing agents, plasticizers, wetting agents, adhesion aids, trapping agents, antiblocking agents, preservatives, and the like, as long as the effects of the present invention are not diminished.

[0086] In this embodiment, it is preferable that the electron beam curable composition is substantially free of photopolymerization initiators. By substantially free of photopolymerization initiators, the influence of components derived from photopolymerization initiators is eliminated, resulting in improved gloss, alcohol resistance, abrasion resistance, and low odor. Here, "substantially free" in this specification means that it is not intentionally added, and the content due to unintentional addition is less than 1% by mass. Unintentional additions include cases where trace amounts are present in each raw material, or contamination during the composition manufacturing process or the printing process.

[0087] Furthermore, it is preferable that the electron beam curable composition of this embodiment substantially does not contain organic solvents. Organic solvents used as viscosity modifiers in printing inks may contain MOSH / MOAH, which are persistent organic pollutants. Also, by not containing volatile components (Non-VOC), it is possible to reduce the environmental burden and improve work safety. Therefore, in this embodiment, it is preferable that the composition substantially does not contain organic solvents.

[0088] <Viscosity> In this embodiment, the electron beam curable composition preferably has a viscosity (at 25°C, 100 rpm) of 1200 mPa·s or less, more preferably 50 to 500 mPa·s, and particularly preferably 100 to 300 mPa·s, as measured by an E-type viscometer, from the viewpoint of leveling properties and repulsion. If the viscosity (at 25°C, 100 rpm) of the electron beam curable composition measured by an E-type viscometer is 1200 mPa·s or less, the leveling properties are good, and it becomes easy to control the height Svk of the protruding valleys to 0.8 μm or less. On the other hand, if the viscosity is less than 100 mPa·s, the electron beam curable composition tends to repel on the substrate, resulting in a deterioration of appearance. If the viscosity is higher than 1200 mPa·s, the leveling properties decrease, resulting in a deterioration of appearance.

[0089] <Method for producing electron beam curable compositions> The electron beam curable composition of this embodiment can be manufactured by mixing and stirring a (meth)acrylate compound and other components as needed for about 30 minutes to 3 hours using a mixer or the like. Alternatively, two or more (meth)acrylate compounds may be mixed and stirred in advance, and then other components as needed may be added to manufacture the composition.

[0090] <Manufacturing of the overcoat layer> As methods for printing or coating the electron beam curable composition of the present embodiment, coating using a roll coater, gravure coater, flexo coater, air doctor coater, blade coater, air knife coater, squeeze coater, impregnation coater, transfer roll coater, kiss coater, curtain coater, cast coater, spray coater, die coater, etc., offset printing (ordinary lithography using dampening water and waterless lithography without using dampening water), flexographic printing, gravure printing, screen printing, etc. can be mentioned. In addition, in in-line printing and off-line printing, various inks such as UV curable, electron beam curable, heat drying type, evaporation drying type, oxidation polymerization type, penetration drying type, thermal polymerization type, two-component curable type, liquid toner type, powder toner type can be used in combination as needed. For coating the overcoat layer, it is preferable to apply an anilox roll with a line count of 100 to 500 Line / inch and a cell volume of 8 to 20 cm 3 / m 2 By applying the above anilox roll, the smoothness of the cured coating film is improved, and it becomes easy to control the protrusion valley height Svk to 0.8 μm or less.

[0091] <Coating amount of overcoat layer> The coating amount of the electron beam curable composition in the overcoat layer is preferably 2 g / m 2 or more and 5 g / m 2 or less, and more preferably 2.5 g / m 2 or more and 4.5 g / m 2 or less. When the coating amount is 2 g / m 2 or more and 5 g / m 2 or less, the smoothness of the overcoat layer is good, so it is easy to control the protrusion valley height Svk to 0.8 μm or less, the appearance is good, the alcohol resistance and abrasion resistance are good, and there is no curling or cracking of the coating film due to curing shrinkage. On the other hand, when the coating amount is less than 2 g / m 2 it is difficult to obtain sufficient coating film strength, so the alcohol resistance and abrasion resistance tend to deteriorate. When the coating amount is 5 g / m2 If the temperature is higher, the appearance tends to deteriorate due to curling and cracking of the coating film caused by curing shrinkage, and a decrease in leveling properties.

[0092] <Electron beam irradiation conditions> The electron beam curable composition of this embodiment is applied to a printed layer by various printing methods, then cured by passing it through an electron beam irradiator to form an overcoat layer. The electron beam used for curing is preferably adjusted to an irradiation dose of 15-60 kGy, more preferably 20-45 kGy, at an acceleration voltage of 50-200 kV, more preferably 80-110 kV, considering the balance between damage to the film and the curability of the electron beam curable composition. An irradiation dose of 15-60 kGy makes it easy to control the nanoindentation hardness to 50-200 MPa, obtains sufficient film strength, and suppresses problems caused by film damage such as reduced film strength, odor, and yellowing.

[0093] The oxygen concentration during electron beam irradiation is preferably 500 ppm or less, and more preferably 300 ppm or less. This makes electron beam curing less susceptible to surface hardening inhibition by oxygen. As a result, electron beam curing offers superior surface hardening compared to ultraviolet curing, enabling the acquisition of high nanoindentation hardness.

[0094] Furthermore, in the laminate of this embodiment, irradiating it with an electron beam causes a crosslinking reaction between each layer, resulting in improved adhesion, heat resistance, and chemical resistance. This is a phenomenon unique to curing with high-energy electron beams and does not occur with curing by ultraviolet irradiation. [Examples]

[0095] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these. In the examples and comparative examples, "parts" refers to "parts by mass," and "%" refers to "mass%."

[0096] <Preparation of electron beam curable compositions and ultraviolet curable compositions> The details of the materials used are as follows:

[0097] (Meth)acrylate compounds having propylene oxide as a constituent unit) • TPGDA: Manufactured by Daicel Ornex, TPGDA (Tripropylene Glycol Diacrylate) • Miramer M2040: PPG400DA (Polypropylene Glycol Diacrylate) • Etermer EM 2381: Manufactured by Eternal Materials, TMP(PO)3TA (PO(3 molar) modified trimethylolpropane triacrylate) • OTA-480: Manufactured by Daicel Ornex, GPTA (Glycerin Propoxy Triacrylate) • NK Ester ATM-4P: Manufactured by Shin-Nakamura Chemical Industry Co., Ltd., PE(PO)4TA(PO(4 molar) modified pentaerythritol tetraacrylate) • NK Ester A-DPH-6PA: Manufactured by Shin-Nakamura Chemical Industry Co., Ltd., DPHA(PO)6 (PO(6 molar) modified dipentaerythritol hexaacrylate)

[0098] (Meth)acrylate compounds that do not contain propylene oxide as a constituent unit) • Miramer M122: Manufactured by MIWON, LA (Lauryl Acrylate) • Miramer M280: Manufactured by MIWON, PEG400DA (polyethylene glycol diacrylate) • EBECRYL 130: Manufactured by Daicel Ornex, containing TCDDA (tricyclodecanedimethanol diacrylate) • Photomer 4028: EO-modified bisphenol A diacrylate, manufactured by IGM. • Miramer M300: Manufactured by MIWON, contains TMPTA (trimethylolpropane triacrylate) • Miramer M3130: Manufactured by MIWON, TMP(EO)3TA (EO(3 molar) modified trimethylolpropane triacrylate) • Miramer M3160: Manufactured by MIWON, TMP(EO)6TA (EO(6 molar) modified trimethylolpropane triacrylate) • Miramer M3190: Manufactured by MIWON, TMP(EO)9TA (EO(9 molar) modified trimethylolpropane triacrylate) • Miramer M3150: Manufactured by MIWON, TMP(EO)15TA (EO(15 mol) modified trimethylolpropane triacrylate) • Funcryl FA-731A: Manufactured by Hitachi Chemical Co., Ltd., Tris(2-acryloyloxyethyl) isocyanurate • Miramer M410: Manufactured by MIWON, containing DiTMPTA (ditrimethylolpropanetetraacrylate) • Miramer M600: Manufactured by MIWON, contains DPHA (Dipentaerythritol Hexaacrylate) • EBECRYL820: Polyester acrylate oligomer, manufactured by Daicel Ornex Co., Ltd. • EBECRYL8409: Polyurethane acrylate oligomer, manufactured by Daicel Ornex Co., Ltd. • MIRAMER PE2160: Epoxy acrylate oligomer, manufactured by MIWON.

[0099] (resin) • Beamset 271MS: Amino group-containing styrene acrylic resin manufactured by Arakawa Chemical Industries, Ltd. (Extender pigments) • AEROSIL R972: Manufactured by Aerosil Japan, average primary particle size 16 nm, specific surface area 110 m² 2 ( / g, dry silica) (Resin fine particles) • SST 3H-RC: Manufactured by Shamrock, average particle size 4.0 μm, polytetrafluoroethylene resin microparticles. • Cerafloure991: Manufactured by Bic Chemie, average particle size 5.0 μm, polyethylene resin microparticles. • Art Pearl J4PY: Manufactured by Negami Kogyo Co., Ltd., average particle size 2.2 μm, acrylic resin microparticles. • Tospar 130: Manufactured by Momentive, average particle size 2.7 μm, silicone resin microparticles. (Leveling agent) • TEGO Rad 2100: Polyether-modified polydimethylsiloxane resin with acryloyl groups, manufactured by Evonik. (Antifoaming agent) • BYK-1790: BYK Corporation, antifoaming agent (Photopolymerization initiator) • SB-PI712: Manufactured by Sort, 4-methylbenzophenone • Daido UV Cure 174: Manufactured by Daido Chemical Industries, Ltd., containing 1-hydroxycyclohexyl phenyl ketone. (Photopolymerization initiator) • Amino alcohol MDA: Manufactured by Nippon Emulsifier Co., Ltd., N-methyldiethanolamine

[0100] (Manufacturing Example 1) 97.0 parts of Etermer EM 2381 as a (meth)acrylate compound having propylene oxide as a constituent unit, 1.0 part of AEROSIL R972 as an extender pigment, 0.5 parts of SST 3H-RC as resin fine particles, 1.0 part of TEGO Rad 2100 as a leveling agent, and 0.5 parts of BYK-1790 as an antifoaming agent were mixed in this proportion, and stirred using a rotation-revolution type mixer to obtain the electron beam curable composition of Production Example 1.

[0101] (Manufacturing examples 2-36) Except for using each material according to the composition shown in Table 1, electron beam curable compositions for Production Examples 2-34 and ultraviolet curable compositions for Production Examples 35 and 36 were obtained by the same method as in Production Example 1.

[0102] <Water-based overcoat> For Comparative Example 13, TW083AQ OP varnish manufactured by Toyo Ink Co., Ltd. was used as the water-based overcoat.

[0103] <Solvent-based overcoat> For Comparative Example 14, PANNECO AM Medium manufactured by Toyo Ink Co., Ltd. was used as the solvent-based overcoat.

[0104] (Production Example 37) (Preparation of Aqueous Inkjet Ink) (Adjustment of Aqueous Pigment Dispersion) 20 parts of C.I. Pigment Blue 15:3, 20 parts of a varnish (solid content 25%) of a colorant-dispersing resin (a water-soluble resin containing styrene, acrylic acid, and stearyl methacrylate as constituent units in a mass ratio of 25:40:35, having a weight-average molecular weight of 25,000 and an acid value of 185 mgKOH / g), and 60 parts of water were put into a mixing container, and then thoroughly mixed (pre-dispersed) with a stirrer. Next, this dispersion was carried out using a Dyno Mill (bead mill manufactured by Shinmaru Enterprises Co., Ltd.) with a volume of 0.6 L filled with zirconia beads having a diameter of 0.5 mm to obtain a blue aqueous pigment dispersion. (Adjustment of Aqueous Inkjet Ink) 20 parts of the above aqueous pigment dispersion, 12 parts of PE1126 (varnish of an acrylic emulsion manufactured by Starlight PMC Co., Ltd., acid value 50 mgKOH / g, glass transition temperature -12°C, solid content 41.5%), 30 parts of 1,2-propanediol, 1 part of Surfynol 465, 0.1 part of Proxel GXL, and 36.9 parts of water were sequentially put into a mixing container and mixed with a stirrer for 1 hour. Then, filtration was carried out using a depth type filter with a pore diameter of 1 μm to remove coarse particles, thereby obtaining a blue aqueous inkjet ink.

[0105] (Production Example 38) (Preparation of UV Inkjet Ink) (Adjustment of UV Pigment Dispersion) 20 parts of C.I. Pigment Blue 15:4, 4 parts of Solsperse 32000 (colorant-dispersing resin manufactured by Lubrizol Corporation), 75.5 parts of phenoxyethyl acrylate, and 0.1 part of dibutylhydroxytoluene (polymerization inhibitor) were put into a mixing container, and then thoroughly mixed (pre-dispersed) with a stirrer. Next, this dispersion was carried out using a Dyno Mill (bead mill manufactured by Shinmaru Enterprises Co., Ltd.) with a volume of 0.6 L filled with zirconia beads having a diameter of 0.5 mm to obtain a blue UV pigment dispersion. (Adjustment of UV Inkjet Ink) Ten parts of the above UV pigment dispersion, forty parts of 2-(2-vinyloxyethoxy)ethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 31.9 parts of phenoxyethyl acrylate, one part of dipropylene glycol diacrylate, six parts of OMNIRAD819 (polymerization initiator manufactured by IGM RESINS), six parts of OMNIRAD TPO H (polymerization initiator manufactured by IGM RESINS), four and a half parts of KAYACURE DETX-S (sensitizer manufactured by Nippon Kayaku Co., Ltd.), 0.1 parts of BYK-UV3500 (siloxane-based surfactant manufactured by BYK), and 0.1 parts of dibutylhydroxytoluene were sequentially added to a mixing container. Next, the contents of the mixing container were heated to 50°C, and the mixture was stirred with a stirrer until the polymerization initiator dissolved. Then, the mixture was filtered using a depth-type filter with a pore size of 1 μm to remove coarse particles, thereby obtaining a blue UV inkjet ink.

[0106] [Table 1]

[0107] [Table 1]

[0108] [Table 1]

[0109] <Method for fabricating laminated structures> The laminate is formed by the steps of printing ink onto a substrate to form a printed layer, and coating the printed layer with an electron beam-curable composition, irradiating it with an electron beam, and forming an overcoat layer.

[0110] (Example 1) Using an HP Indigo 20000 digital printing press manufactured by HP Corporation, a primer layer (Michelman Digiprime 050) and then blue ink (HP Indigo Electroink) were printed on a substrate in that order to obtain a print with 100% blue ink (solid color across the entire surface). The substrate used was a laminated material, as described later. Next, the electron beam-curable composition obtained in Production Example 1 was coated onto the printed layer of a printed material, and irradiated with an electron beam to obtain the laminate of Example 1. A flexographic printing press (MIRAFLEX CM, manufactured by W&H) equipped with an electron beam irradiator was used for coating the electron beam-curable composition. Coating was performed using in-line corona treatment at a coating speed of 100 m / min. Anilox rolls have a line count of 100-500 lines / inch and a cell capacity of 8-20 cm². 3 / m 2 The engraving pattern was hexagonal. The plate material used was a Kodak Flexcel NXH digital flexographic plate. The application amount of the electron beam curable composition was 2-5 g / m² after curing. 2 The paper was printed in this manner. Electron beam irradiation was performed using an ESI EZ-CURE electron beam irradiator under the conditions of an acceleration voltage of 110kV and an irradiation dose of 30kGy. The resulting laminates were subjected to measurements of the protruding valley height (Svk) and nanoindentation hardness, and the results are shown in Table 2. <Laminated material used as the base material> A laminate was obtained by laminating a biaxially oriented polypropylene film (product name: FOR-BT, thickness 20 μm) manufactured by Futamura Chemical Co., Ltd. with an unoriented polypropylene film (FHK, 30 μm) manufactured by Futamura Chemical Co., Ltd. using a laminating machine. EA-N373A / EA-N6173 manufactured by Toyo Morton Co., Ltd. was used as the laminating adhesive. The coating amount was 1.5-2.0 g / m². 2 The coating was applied in this manner. Next, it was subjected to a 24-hour aging process in an environment of 40°C and 60% to 80% humidity.

[0111] (Examples 2-26) Laminates were fabricated in the same manner as in Example 1, except that electron beam-curable compositions obtained in Manufacturing Examples 2-26 were used.

[0112] (Example 27) A laminate was fabricated in the same manner as in Example 1, except that HSOPP (Futamura Chemical Co., Ltd., FOH, 40 μm thick) was used as the substrate.

[0113] (Example 28) A laminate was prepared in the same manner as in Example 1, except that white colored PE (SE620L, 70 μm thick, manufactured by Tamapoly Co., Ltd.) was used as the base material.

[0114] (Example 29) A laminate was fabricated in the same manner as in Example 1, except that a PP seal label (FOREST PP WHITE FTC 60, 60 μm thick, manufactured by UPM Laflatack Co., Ltd.) was used as the base material.

[0115] (Example 30) A laminate was prepared in the same manner as in Example 1, except that coated paper sticker labels (Lintec Corporation NP Coat PW8E) were used as the base material.

[0116] (Example 31) A laminate was prepared in the same manner as in Example 1, except that Yupo paper sticker labels (Lintec Corporation Yupo 80 (UV) PW8K Blue) were used as the base material.

[0117] (Example 32) A laminate was prepared in the same manner as in Example 1, except that a PET seal label (PET50(A)PAT18LK manufactured by Lintec Corporation) was used as the base material.

[0118] (Example 33) The laminate was fabricated in the same manner as in Example 1, except that the electron beam irradiation dose was 15 kGy.

[0119] (Example 34) The laminate was fabricated in the same manner as in Example 1, except that the electron beam irradiation dose was 60 kGy.

[0120] (Example 35) (Pre-printed using water-based inkjet ink) A laminate was prepared in the same manner as in Example 1, except that the printed layer was printed with water-based inkjet ink. The water-based inkjet ink was printed using a Kyocera head (KJ4B-1200 model, design resolution 1200 dpi) at a printing speed of 30 m / min and a drying temperature of 70°C to obtain a print with 100% blue ink (solid color). The printing conditions were a frequency of 20 kH, 1200 × 1200 dpi, and a drop volume of 2.5 pL.

[0121] (Example 36) (Pre-printed using UV inkjet ink) A laminate was prepared in the same manner as in Example 1, except that the printed layer was printed with UV inkjet ink. For UV inkjet printing, a Kyocera head (KJ4A-RH model, design resolution 600 dpi) was used as the IJ head, and the printing speed was 30 m / min. Drying was performed using an ultraviolet exposure system (GEW 240 W / cm metal halide lamp) to obtain a print with 100% blue ink (solid color across the entire surface). The printing conditions were a frequency of 20 kH, 1200 × 1200 dpi, and a drop volume of 2.5 pL.

[0122] (Comparative Examples 1-10) Laminates were fabricated in the same manner as in Example 1, except that electron beam-curable compositions obtained in Manufacturing Examples 25-34 were used.

[0123] (Comparative Examples 11-12) (UV-curing overcoat) Laminates were prepared in the same manner as in Example 1, except that the UV-curable compositions obtained in Manufacturing Examples 35-36 were used. A UV flexographic printing press (Nilpeter FA11) was used for coating the UV-curable overcoat. Coating was performed using in-line corona treatment at a coating speed of 100 m / min. The anilox roll had a screen count of 100-500 lines / inch and a cell capacity of 8-20 cm². 3 / m 2 The engraving pattern was hexagonal. The plate material used was a Kodak Flexcel NXH digital flexographic plate. Curing was performed by irradiating with one GEW mercury UV lamp E2C (air-cooled 140W / cm).

[0124] (Comparative Example 13) (Water-based overcoat) Laminates were prepared in the same manner as in Example 1, except that a commercially available water-based overcoat (Toyo Ink TW083AQ OP varnish) was used on the printed layer. A flexographic printing press (W&H MIRAFLEX CM) was used for coating the water-based overcoat. The water-based overcoat was diluted with water using a Zahn cup No. 4 and heated at 25°C for 10-15 seconds. Coating was performed using in-line corona treatment at a coating speed of 100 m / min. The anilox roll had a screen count of 100-500 lines / inch and a cell capacity of 13-30 cm². 3 / m 2 The engraved pattern was hexagonal. The printing plate used was a Kodak Flexcel NXH digital flexographic plate. Drying was performed at an interstation dryer temperature of 80°C and a tunnel dryer temperature of 80°C. The coating amount after drying was 2-5 g / m². 2 It was painted in such a way.

[0125] (Comparative Example 14) (Solvent-based overcoat) A laminate was prepared in the same manner as in Example 1, except that a commercially available solvent-based overcoat (PANNECO AM Medium, manufactured by Toyo Ink Co., Ltd.) was used on the printed layer. A gravure printing press was used to apply the solvent-based overcoat. The solvent-based overcoat was diluted with a mixed solvent of ethyl acetate / isopropyl alcohol (mass ratio 70 / 30) using a Zahn cup No. 3 for 10-15 seconds at 25°C before use. The coating was performed at a speed of 40 m / min, a drying temperature of 50°C, and a gravure plate with a solid pattern depth of 30 μm was used. The coating amount after drying was 2-5 g / m². 2 It was painted in such a way.

[0126] [Table 2]

[0127] [Table 2]

[0128] [Table 2]

[0129] <Various evaluations> The following evaluations were performed on the obtained laminates. The evaluation results are shown in Table 2.

[0130] (Alcohol-resistant) For the laminates of the examples and comparative examples, a cotton swab immersed in a 99.5% ethanol solution was used to rub the surface at a rate of one back-and-forth motion per second, and the number of back-and-forth motions until the overcoat layer was removed was measured. A rating of 3 or higher is practically preferable. (Evaluation Criteria) 5:50 times or more 4: 40 times or more but less than 50 times 3: 20 to less than 30 times 2: 10 to less than 20 times 1: Less than 10 times

[0131] (Glossy finish) For the laminates of the examples and comparative examples, the gloss value (in accordance with JIS Z 8741) was measured at a reflection angle of 60° relative to the printed material using BYK Microtrigloss. The glossiness of the printed material was evaluated from the gloss value according to the following criteria. A rating of 3 to 5 is considered to be within the range of industrially practical use. (Evaluation Criteria) 5: The gloss value is 85 or higher. 4: The gloss value is between 75 and 85. 3: The gloss value is between 65 and 75. 2: The gloss value is between 55 and 65. 1: Gloss value is less than 55

[0132] (Abrasion resistance) The laminates of the examples and comparative examples were subjected to friction resistance tests using a JSPS-type friction fastness tester manufactured by Tester Industries Co., Ltd. (load 500g, 200 cycles of friction, using Kanakin No. 3 (compliant with JIS L0803) as the friction element), and scratches that occurred in the overcoat layer were evaluated. A rating of 3 to 5 is considered to be within the range of industrially practical use. (Evaluation Criteria) 5: No scratches at all 4. The wound covers less than 10% of the area. 3: The wound covers 10% or more but less than 30% of the total area. 2: The wound covers 30% or more but less than 50% of the area. 1: The wound covers 50% or more of the area.

[0133] (Odor) The laminate, immediately after the overcoat layer was applied, was cut into 100mm x 100mm sections and sealed in glass bottles. The odor intensity was evaluated by five people using sensory evaluation, and the average value was used for the rating. A rating of 3 or higher is considered practically preferable. (Evaluation Criteria) 4: There was almost no odor. 3: A slight odor was detected. 2: The odor was clearly noticeable. 1: The odor was very strong.

[0134] As described above, the laminate (Example) which is one embodiment of the present invention, is a laminate having a substrate, a printed layer, and an overcoat layer in this order, wherein the printed layer is a layer printed by a digital printing method, the overcoat layer is a layer cured by an electron beam using an electron beam from an electron beam curable composition containing a (meth)acrylate compound, the electron beam curable composition substantially does not contain a photopolymerization initiator, the overcoat layer has a protruding valley height Svk of 0.8 μm or less as defined in ISO 25178, and a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577. As a result, the alcohol resistance, gloss, abrasion resistance, and odor were at a practical level. On the other hand, Comparative Examples 1 and 7 had a nanoindentation hardness of less than 50 MPa. As a result, their alcohol resistance and abrasion resistance were insufficient. This is thought to be due to insufficient crosslinking density in the electron beam curable composition. Comparative Examples 2-4 had a protruding valley height (Svk) greater than 0.8 μm and a nanoindentation hardness of less than 50 MPa. As a result, gloss and abrasion resistance were insufficient, and comparative examples 2 and 3 also exhibited insufficient alcohol resistance. This is thought to be due to insufficient crosslinking density in the electron beam curable composition, as well as the occurrence of numerous fine irregularities and pinhole-like defects in the overcoat layer. Comparative Examples 5, 6, and 8-10 had nanoindentation hardness of 50-200 MPa, but the protruding valley height (Svk) was greater than 0.8 μm. As a result, the gloss was insufficient, and Comparative Example 5 also exhibited insufficient alcohol resistance. This is thought to be because, although the hardness of the overcoat layer was sufficient and it showed good abrasion resistance, the gloss was particularly degraded due to the large number of fine irregularities and pinhole-like defects. Comparative Example 11 is an UV-curable overcoat in which some of the (meth)acrylate compounds in Example 1 were replaced with a photopolymerization initiator, etc. The protruding valley height Svk was 0.8 μm or less, and the nanoindentation hardness was 50 MPa to 200 MPa, but the odor was insufficient. This is thought to be due to unreacted photopolymerization initiators or decomposition products of the photopolymerization initiator remaining in the overcoat layer. Furthermore, it had inferior alcohol resistance, gloss, and abrasion resistance compared to Example 1. In particular, regarding alcohol resistance and abrasion resistance, Comparative Example 11 is UV-cured, so it is possible that surface hardening was inhibited by oxygen. It is also possible that this is due to the absence of a crosslinking reaction between the ink and the substrate, as occurred when cured by electron beam. In addition, it is possible that it is due to residual initiator-derived components. Comparative Example 12's overcoat layer is an UV-curable overcoat containing a non-reactive resin and a photopolymerization initiator, corresponding to the composition described in the examples of Patent Document 1 of the prior art literature. The nanoindentation hardness was less than 50 MPa, resulting in insufficient alcohol resistance and odor. This is thought to be due to the presence of unreacted photopolymerization initiators or decomposition products of the photopolymerization initiators after the reaction in the overcoat layer, resulting in insufficient odor. Also, similar to Comparative Example 11, a deterioration of surface properties specific to UV curing compared to electron beam curing is thought to be present. Furthermore, it is thought that the inclusion of a non-reactive resin to improve adhesion significantly deteriorates alcohol resistance. Comparative Example 13 had a water-based overcoat layer and a protruding valley height (Svk) of 0.8 μm or more. As a result, it exhibited insufficient alcohol resistance, gloss, and abrasion resistance. This is thought to be due to the high surface tension of the water-based overcoat, which makes it easily repelled on the digital printing layer, resulting in a large number of fine irregularities and pinhole-like defects in the overcoat layer. Furthermore, it is thought to be due to the fact that, because it is dried by evaporation, crosslinking reactions like those in electron beam-curable compositions do not occur. Comparative Example 14 had a solvent-based overcoat layer and a nanoindentation hardness of less than 50 MPa. As a result, it exhibited insufficient alcohol resistance, gloss, and abrasion resistance. Solvent-based overcoats are primarily composed of flexible resins soluble in solvents, which is thought to be the reason for the deterioration of alcohol resistance and abrasion resistance. Furthermore, the extensive use of resin microparticles to compensate for the insufficient surface strength is thought to be the cause of the deterioration of gloss. Additionally, because it is dried by evaporation, it is thought that crosslinking reactions like those in electron beam curable compositions do not occur, which is also a contributing factor.

[0135] As is clear from the above, the laminate of the present invention has a specific configuration, and it has been proven that by having the protruding valley height Svk and nanoindentation hardness within a specific range, it exhibits excellent alcohol resistance, gloss, abrasion resistance, and low odor.

Claims

1. A laminate having a substrate, a printed layer, and an overcoat layer in this order, The aforementioned printing layer is a printing layer produced by a digital printing method. The overcoat layer is a layer made of a cured product of an electron beam curable composition containing a (meth)acrylate compound. The electron beam curable composition substantially does not contain a photopolymerization initiator. A laminate in which the overcoat layer has a protruding valley height Svk of 0.8 μm or less as defined in ISO 25178, and a nanoindentation hardness of 50 to 200 MPa as defined in ISO 14577.

2. The laminate according to claim 1, wherein the viscosity of the electron beam curable composition measured by an E-type viscometer (25°C, 100 rpm) is 1200 mPa·s or less.

3. The amount of electron beam-curable composition applied to the overcoat layer is 2 g / m². 2 5g / m or more 2 The laminate according to claim 1, which is as follows:

4. The laminate according to claim 1, wherein the (meth)acrylate compound comprises a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit.

5. The laminate according to claim 4, wherein the content of a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit is 5 to 98% by mass of the total amount of the electron beam curable composition.

6. The laminate according to claim 4, wherein a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a constituent unit comprises a compound containing X to 3X propylene oxide as constituent units in the molecule, where X is the number of (meth)acryloyl groups in the molecule.

7. A packaging material comprising a laminate according to any one of claims 1 to 6.

8. A seal label comprising a laminate according to any one of claims 1 to 6.

9. A method for manufacturing a laminate according to claim 1, A process for manufacturing a printed layer on a substrate using digital printing, A process of manufacturing an overcoat layer by applying an electron beam-curable composition onto a printed layer and irradiating it with an electron beam under conditions of an acceleration voltage of 50 to 200 kV and an irradiation dose of 15 to 60 kGy, A method for manufacturing a laminate, including the following:

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