Laminate and method for manufacturing the laminate

Abstract

To provide a laminate having a digitally printed layer, which is excellent in gloss, alcohol resistance, abrasion resistance and low odor. [Solution] A laminate having a substrate, a printing layer, and an overcoat layer in this order, wherein the printing layer is a printing layer produced by a digital printing method, the overcoat layer is a layer obtained by curing an electron beam-curable composition containing a (meth)acrylate compound with an electron beam, the electron beam-curable composition being substantially free of a photopolymerization initiator, and the overcoat layer has a protruding valley height Svk of 0.8 μm or less as specified in ISO 25178 and a nanoindentation hardness of 50 to 200 MPa as specified in ISO 14577.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to laminates and methods for making laminates. [Background technology]

[0002] In the traditional printing industry, systems such as gravure printing, offset printing, and flexographic printing, which require plate-making processes and print the same design in large lots, were the norm. However, in recent years, there has been an increase in demand for short-run printing (variable printing) for a wide variety of designs and shorter delivery times, while the demand for large-run printing has decreased. In this environment, digital printing, which does not require plate-making processes, is becoming increasingly popular as a means of achieving variable printing and shorter delivery times.

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

[0004] Overcoats are required to have various physical properties depending on their intended use, such as abrasion resistance, glossiness that affects attractiveness, and resistance to alcohol used in alcohol sanitization and disinfection.

[0005] Due to the characteristics of the raw materials, printed materials produced by digital printing have poor abrasion resistance, gloss, and alcohol resistance, as mentioned above. Even if the surface is protected with a conventional solvent- or water-based heat-drying overcoat, it is difficult to achieve these properties at a practically sufficient level. For this reason, digital printing is difficult to achieve as a surface printing method, and its use as a lamination configuration for reverse printing has become mainstream. Therefore, the use of active energy ray-curable overcoats, which have strong coating properties, has attracted attention for achieving surface printing in digital printing.

[0006] In recent years, the use of curing technology using active energy rays has expanded in the printing industry due to the following advantages: shortening process time through instant drying, reducing environmental impact and improving work safety by being non-volatile organic compounds (Non-VOC), and realizing strong coating film properties through crosslinking reactions.

[0007] The use of active energy ray curing technology, which began in the field of commercial printing based on paper substrates such as flyers and posters, has expanded to various application fields due to the development of printing technology including printing machines and printing inks, and is now expanding its application field to various film substrates, and is increasingly being used as packaging materials and containers for food, cosmetics, and toys, as sticker labels, card games, etc.

[0008] Here, ultraviolet (UV)-curable overcoats are the mainstream active energy ray-curable overcoats. However, UV-curable overcoats contain a significant amount of photopolymerization initiators, 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 from unreacted or decomposed photopolymerization initiators and their potential health effects. In addition, UV-curing also poses a problem of damage to substrates due to the heat generated by the UV-emitting lamp. Furthermore, inert resins are sometimes used in UV-curable overcoats to improve adhesion and leveling on digital printing surfaces. However, while inert resins improve adhesion and leveling, they also significantly reduce alcohol resistance and abrasion resistance.

[0009] Against this background, electron beam (EB) curable overcoats are attracting attention as opposed to ultraviolet (UV) curable overcoats, as they do not require photopolymerization initiators, cause less thermal damage to the substrate, and have good adhesion to digitally printed surfaces.

[0010] The raw materials that make up electron beam (EB) curable overcoats are similar to those of ultraviolet (UV) curable overcoats, except that they do not require initiators. The (meth)acrylate compounds, which are the main raw materials, often have high surface tension on digitally printed surfaces. This is one of the reasons why they have poor leveling on digitally printed surfaces and a reduced gloss. Leveling is an issue that is not limited to electron beam (EB) curable overcoats, but is a common issue for active energy ray curable overcoats, and further improvement is required.

[0011] Various attempts have been made to address the issue of realizing such 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 di- to tri-functional (meth)acrylate monomer having a cyclic structure, and a di- to tetra-functional (meth)acrylate monomer to achieve excellent adhesion to a substrate and an ink layer, gloss, low curling properties, and high curability.

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

[0014] Patent Document 3 discloses a technique in which a polymer ink containing a polyolefin binder is irradiated with an electron beam to at least partially crosslink the polymer ink, thereby improving the heat resistance and pressure resistance of the polymer ink. It also discloses that the same effect can be obtained when an EB-curable lacquer is applied.

[0015] However, with the above invention, it is difficult to obtain a laminate including a digitally printed layer that satisfies all of the following requirements: gloss, coating resistance such as alcohol resistance and abrasion resistance, and low odor, and further research is needed. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Japanese Patent Application Publication No. 2019-019256 [Patent Document 2] Japanese Patent Application Publication No. 2018-145283 [Patent Document 3] Special Publication No. 2019-509196 Summary of the Invention [Problem to be solved by the invention]

[0017] The problem to be solved by the present invention is to provide a laminate having a digitally printed layer that is excellent in gloss, coating resistance such as alcohol resistance and abrasion resistance, and low odor. [Means for solving the problem]

[0018] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by the laminate shown below, and have thus 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 printing layer, and an overcoat layer in this order, The printed layer is a printed 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 is substantially free of a photopolymerization initiator, The overcoat layer has a protruding valley height Svk defined in ISO 25178 of 0.8 μm or less and a nanoindentation hardness defined in ISO 14577 of 50 to 200 MPa.

[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. <1> The laminate according to claim 1.

[0021] <3> The coating amount of the electron beam curable composition in the overcoat layer is 2 g / m 2 More than 5g / m 2 The following is the above <1> or <2> The laminate according to claim 1.

[0022] <4> The (meth)acrylate compound contains two or more (meth)acryloyl groups in the molecule and includes a (meth)acrylate compound having propylene oxide as a structural unit. <1> ~ <3> The laminate according to any one of the above.

[0023] <5> The content of the (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a structural unit is 5 to 98 mass % of the total amount of the electron beam curable composition. <4> The laminate according to claim 1.

[0024] <6> The (meth)acrylate compound has two or more (meth)acryloyl groups in the molecule and has propylene oxide as a structural unit, and when the number of (meth)acryloyl groups in the molecule is X, the (meth)acrylate compound includes a compound containing X to 3X propylene oxide as a structural unit in the molecule. <4> or <5> The laminate according to claim 1.

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

[0026] <8> the above <1> ~ <6> A seal label comprising any one of the laminates.

[0027] <9> the above <1> ~ <6> A method for producing the laminate according to any one of the preceding claims, A step of producing a printing layer on a substrate by digital printing; a step of applying an electron beam curable composition onto the printing layer and irradiating the composition with an electron beam at an acceleration voltage of 50 to 200 kV and an exposure dose of 15 to 60 kGy to produce an overcoat layer; A method for producing a laminate, comprising: [Effects of the Invention]

[0028] The present invention has made it possible to provide a laminate having a digitally printed layer that is excellent in gloss, coating resistance such as alcohol resistance and abrasion resistance, and low odor. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0030] The terms used in this specification are explained below. "(Meth)acryloyl" means acryloyl and / or methacryloyl (methacryloyl), and "(meth)acrylate" means acrylate and / or methacrylate (methacrylate). Furthermore, "PO" stands for "propylene oxide" and "EO" stands for "ethylene oxide."

[0031] <Laminate> One embodiment of the present invention relates to a laminate having, in this order, a substrate, a digitally printed layer, and an overcoat layer, wherein the overcoat layer is made of a cured product of an electron beam-curable composition containing a (meth)acrylate compound, and is characterized in that 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. The electron beam-curable composition is substantially free of photopolymerization initiators and can be cured by irradiation with an electron beam.

[0032] The laminate of this embodiment can be used for various purposes. 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 the present embodiment is not particularly limited, and can be known, but is preferably a film substrate and a paper substrate.For example, polyolefin substrates such as polyethylene and polypropylene, synthetic paper such as Yupo paper made from polypropylene and inorganic filler, polyester substrates such as polyethylene terephthalate and polylactic acid, polycarbonate substrates, polystyrene, AS resin, ABS resin and other polystyrene-based substrates, nylon substrates, polyamide substrates, polyvinyl chloride substrates, polyvinylidene chloride substrates, cellophane substrates, paper substrates, aluminum substrates, etc., or film substrates made of these composite materials.Among them, polyolefin-based films are preferred from the viewpoint of recyclability. Alternatively, a vapor-deposited substrate may be used, in which an inorganic compound such as silica, alumina, or aluminum is vapor-deposited onto a film substrate. Furthermore, the vapor-deposited surface may be coated with polyvinyl alcohol or the like. It is preferable that the surface of the substrate to be printed (the surface in contact with the printing layer) is treated to facilitate adhesion. Specific examples of such treatments include corona discharge treatment, ultraviolet / ozone treatment, plasma treatment, oxygen plasma treatment, and primer treatment. Furthermore, if sufficient adhesion cannot be obtained with a polyethylene terephthalate substrate, a surface treatment such as acrylic coating treatment, polyester treatment, polyurethane treatment, or polyvinylidene chloride treatment may be performed.

[0034] The paper substrate may be ordinary paper or cardboard, and the film thickness is not particularly limited. The printing surface may be subjected to an easy-adhesion treatment. The paper substrate may be subjected to a vapor deposition treatment of a metal such as aluminum for the purpose of imparting design features. The paper substrate may also be subjected to a surface coating treatment with an acrylic resin, a urethane resin, a polyester resin, a polyolefin resin, or other resin, and may further be subjected to a surface treatment such as a corona treatment. For example, specific examples of surface-treated paper substrates include coated paper and art paper.

[0035] A laminate having a heat-sealable layer may be used as the substrate. The laminate having a heat-sealable layer is preferably a film or a laminate of a paper substrate and a film having heat-sealability. The heat-sealable film is not particularly limited, and known films can be used. Examples include polyethylenes such as low-density polyethylene (LDPE), 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-based 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 is preferably in the range of 10 to 60 μm, more preferably in the range of 15 to 40 μm, taking into consideration the processability and heat sealability of the laminate. The method for laminating the heat seal layer is not particularly limited, and examples thereof include a method of thermally laminating a substrate and a sealant film (thermal lamination, dry lamination) and a method of melting a sealant resin, extruding it onto a substrate, and cooling and solidifying it to form a laminate (extrusion lamination). A heat-sealing agent may also be applied as a heat-sealing layer.

[0036] A sticker label may be used as the substrate. There are no particular restrictions on the sticker label, and known sticker labels can be used. A film or paper substrate is preferred as the surface substrate of the sticker label. Preferred film surface substrates are polyester film, vinyl chloride film, synthetic paper, polypropylene film, polyethylene film, polystyrene film, and ABS film. Preferred paper surface substrates are wood-free paper, art paper, coated paper, gloss paper, foil paper, and special paper. There are no particular restrictions on the film thickness. The printed surface may be treated to make it easy to adhere.

[0037] <Print layer> The printed layer in the laminate of this embodiment is a digitally printed layer, and is not particularly limited and can be selected from known methods. Examples of digital printing methods include wet (liquid toner) electrophotography, dry (powder toner) electrophotography, and inkjet methods (UV curable, aqueous, and solvent). In a preferred embodiment, printing is performed using an Indigo® digital printer manufactured by Hewlett-Packard. The printed layer is preferably electrophotographically printed 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, the (meth)acrylate compound refers to a compound having a (meth)acryloyl group in the molecule.

[0039] In the laminate of this embodiment, the electron beam curable composition constituting the overcoat layer is not particularly limited as long as the cured coating film satisfies the desired requirements for the protruding valley height Svk and hardness. Although not particularly limited, the electron beam curable composition described below can be suitably used.

[0040] (Height of the protruding valley of the overcoat layer Svk) The overcoat layer in the laminate of this embodiment has a protruding valley height Svk of 0.8 μm or less (may be 0) as defined in ISO 25178. The protruding valley height Svk of the overcoat layer is preferably 0.5 μm or less (may be 0). The protruding valley height Svk is a three-dimensional surface roughness measurement in accordance with ISO 25178 and is one of the function and related parameters using the material ratio curve. The core is the surface area excluding the area outside the height range of the equivalent line where the material ratio is 0% to 100%. The area recessed below the core on the material ratio 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 lubrication accumulates. The smaller the protruding valley height Svk, the smoother the overcoat layer and the better the appearance.

[0041] The protruding valley height Svk of the overcoat layer was measured 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 a white light interference scan mode and an objective lens magnification of 10x. The image processing conditions were an S-filter of 5 μm, an L-filter of 0.8 mm, no F-operation, correction for end effect, and an evaluation area of ​​1406 μm x 1055 μm (full area specified).

[0042] (Hardness of 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. The hardness of the overcoat layer is preferably 70 to 150 MPa. The nanoindentation hardness is a value of indentation hardness measured using a micro-area mechanical property evaluation device (nanoindenter) and is defined in ISO 14577. In this specification, the value is measured using a Hysitron TI Premier (manufactured by Bruker). The nanoindenter indents only the very surface layer of the laminate, making it possible to measure the mechanical properties of only the thin overcoat layer without being affected by the substrate. Other measurement methods require too large an indentation load and displacement, making it difficult to measure only the thin layer. In this specification, the hardness of only the overcoat layer is shown.

[0043] The nanoindentation hardness (H) is measured as follows. A triangular pyramidal Berkovich indenter is used as the indenter of the nanoindenter. The Berkovich indenter is pressed into the measurement sample under the indentation conditions described below, and the indentation depth h (nm) against the indentation load F (μN) is continuously measured to create a load-displacement curve. The maximum indentation load Fmax (μN) is then calculated as the contact projected area Ac (μm) of the indenter and sample at that time. 2 ) to obtain the hardness. In other words, H=Fmax / Ac. Here, Ac is the contact projected area corrected for the indenter tip curvature using a standard sample of fused silica in a standard instrument method. The contact projected area Ac is calculated from the contact depth h (nm), and for an ideal Berkovich indenter, Ac = 24.56h 2 is. The measurement was performed at 25°C, with the indenter being pressed to a depth of 150 nm over 5 seconds, and the load obtained when the indenter was held at the depth of 150 nm for 2 seconds was taken as the maximum indentation load Fmax (μN).The load was then released over 5 seconds until the depth reached 0 nm, and a load-displacement curve was obtained.

[0044] In order to achieve a protruding valley height Svk of 0.8 μm or less, it is effective to improve the leveling properties of the electron beam-curable composition forming the overcoat layer. Methods for improving the 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, leads to significant improvement in 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 reduces the hardness of the cured coating film, making it difficult to achieve a nanoindentation hardness within a specific range. On the other hand, increasing the crosslink density of the cured coating film is effective for achieving a nanoindentation hardness of 50 to 200 MPa. Methods for increasing the crosslink density of the cured coating film include increasing the (meth)acryloyl group concentration of the electron beam-curable composition and optimizing the electron beam irradiation dose. In particular, using a large amount of (meth)acrylate compounds, which are the main components of electron beam-curable compositions, with a high number or concentration of (meth)acryloyl groups leads to a high crosslink density of the cured coating film. However, (meth)acrylate compounds with a high number or concentration of (meth)acryloyl groups tend to have high viscosity and poor leveling properties, making it difficult to achieve a specific range for the protruding valley height Svk.

[0045] In the laminate of this embodiment, the overcoat layer is characterized in that it has a 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. When the valley height Svk and nanoindentation hardness requirements are within the above ranges, the laminate has excellent gloss and excellent coating 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 the overcoat layer in the laminate of the above embodiment.

[0047] The electron beam curable composition of the present embodiment contains a (meth)acrylate compound. In this specification, the term "(meth)acrylate compound" refers to a compound having a (meth)acryloyl group in the molecule.

[0048] Specific examples of the (meth)acrylate compound that can be used to form the electron beam curable composition of the present 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-trimethylsilyl monofunctional (meth)acrylate compounds such as cyclohexanol (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (oxyethyl) (meth)acrylate, 1,4-cyclohexanedimethanol (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, benzyl (meth)acrylate, EO (2 mole)-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, hydroxypivalic acid neo bifunctional (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, cyclohexane dimethanol 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 isocyanuric acid tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and glycerin propoxy tri(meth)acrylate; tetrafunctional (meth)acrylate compounds such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, EO (4 mol)-modified pentaerythritol tetra(meth)acrylate, PO (4 mol)-modified pentaerythritol tetra(meth)acrylate, EO (4 mol)-modified ditrimethylolpropane tetra(meth)acrylate, and PO (4 mol)-modified ditrimethylolpropane tetra(meth)acrylate; pentafunctional (meth)acrylate compounds such as dipentaerythritol penta(meth)acrylate, EO (5 mol)-modified dipentaerythritol penta(meth)acrylate, and PO (5 mol)-modified dipentaerythritol penta(meth)acrylate; Examples thereof include hexafunctional (meth)acrylate compounds such as dipentaerythritol hexa(meth)acrylate, EO (6 mol)-modified dipentaerythritol hexa(meth)acrylate, and PO (6 mol)-modified dipentaerythritol hexa(meth)acrylate. The (meth)acrylate compound may also be one modified with a mono- or polyalkylene oxide other than those mentioned above.

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

[0050] <Epoxy (meth)acrylate> The epoxy(meth)acrylate may be, for example, an epoxy(meth)acrylate which is a reaction product of a glycidyl group contained in an epoxy resin with (meth)acrylic acid having a carboxyl group. Other examples include epoxy(meth)acrylates which are reaction products of 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. Examples of the former include epoxy(meth)acrylates obtained by adding (meth)acrylic acid to a bisphenol A epoxy resin, and epoxy(meth)acrylates obtained by adding (meth)acrylic acid to a novolac epoxy resin.

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

[0052] As the polyisocyanate, known ones can be used, and examples thereof include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. For example, examples of aromatic diisocyanates include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, m-tetramethylxylylene diisocyanate, 1,4-phenylene diisocyanate, and tolylene diisocyanate. Examples of the aliphatic diisocyanate include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene 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(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, and dimer diisocyanate in which the carboxyl group of a dimer acid has been modified with an isocyanate group. Among these, aromatic diisocyanates and / or alicyclic diisocyanates are preferred. Among the above-mentioned exemplary compounds, tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isocyanurates of hexamethylene diisocyanate are preferred.

[0053] <Polyester (meth)acrylate> In this embodiment, the polyester (meth)acrylate may be one obtained by polycondensing a polybasic acid and a polyhydric alcohol by a known method, and the molecular weight and the amount of terminal groups such as hydroxyl groups or carboxyl groups are adjusted by the compounding ratio of the amount of carboxyl groups and the amount of hydroxyl groups. For example, when the amount of carboxyl groups contained in the polybasic acid is greater than the amount of hydroxyl groups contained in the polyhydric alcohol, the terminal functional group becomes a carboxyl group, and the desired polyester (meth)acrylate can be obtained by condensing this with the hydroxyl group of a hydroxyl group-containing (meth)acrylate.

[0054] The polybasic acid may be aliphatic, alicyclic, or aromatic, and may be used without any particular limitation. 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, dodecanedioic acid, pimelic acid, citraconic acid, glutaric acid, itaconic acid, succinic anhydride, maleic anhydride, fatty acids, and dimer acids derived from fatty acids. These aliphatic dicarboxylic acids and their anhydrides may 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] Examples of the polyhydric alcohol 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 (number of moles added: 10 or less), polyoxypropylene glycol (number of moles added: 10 or less), propanediol, 1,3-butanediol, and 1,4-butane. Preferred examples include difunctional aliphatic or alicyclic alcohols such as diol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, cyclohexanedimethanol, tricyclodecane dimethanol, cyclopentadiene dimethanol, and dimer diol, and trifunctional aliphatic or alicyclic alcohols such as glycerin, trimethylolpropane, 1,2,4-butanetriol, and their ethylene oxide adducts (number of moles added: 10 or less) or propylene oxide adducts (number of moles added: 10 or less). Among these, those having a structural unit derived from at least one compound selected from the group consisting of ethylene glycol, propylene glycol, glycerin, and trimethylolpropane are preferred.

[0056] Examples of the hydroxyl group-containing (meth)acrylate include hydroxyl group-containing mono(meth)acrylates such as 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, and 10-hydroxydecyl(meth)acrylate; Hydroxyl group-containing di(meth)acrylates such as glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, Hydroxyl-containing tri(meth)acrylates such as pentaerythritol tri(meth)acrylate, and Hydroxyl group-containing penta(meth)acrylates such as dipentaerythritol penta(meth)acrylate, and Examples of hydroxyl group-containing (meth)acrylates include (meth)acrylates having a terminal hydroxyl group obtained by ring-opening addition of the above-mentioned hydroxyl group-containing (meth)acrylate and 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 above-mentioned hydroxyl group-containing (meth)acrylate. Among these, 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)acrylates, urethane (meth)acrylates, and epoxy (meth)acrylates can also be used. Examples include EBECRYL 820, 824, 837, and 450 (all polyester acrylates) manufactured by Daicel-Allnex Co., Ltd., EBECRYL 8210 and 8409 (all aliphatic urethane acrylates) manufactured by Daicel-Allnex Co., Ltd., and MIRAMER PE2160 (all epoxy acrylates) manufactured by MIWON Co., Ltd.

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

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

[0060] The (meth)acrylate compound in this embodiment preferably contains a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a structural unit. (Meth)acrylate compounds having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a structural unit have low surface tension, which reduces repelling during application, thereby reducing the height of protruding valleys and contributing to improved gloss. Furthermore, a high crosslink density can be obtained after curing, which increases nanoindentation hardness and contributes to improved alcohol resistance and abrasion resistance.

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

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

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

[0064] In a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule and having propylene oxide as a structural unit, the amount of propylene oxide is preferably from X to 3X, and more preferably from X to 2X, of propylene oxide as a structural unit in the molecule, in terms of the balance between gloss and hardness, where X is the number of (meth)acryloyl groups in the molecule.

[0065] The (meth)acrylate compound has two or more (meth)acryloyl groups in the molecule and has propylene oxide as a structural unit, and where X is the number of (meth)acryloyl groups in the molecule, the (meth)acrylate compound containing X to 2X propylene oxide as a structural unit in the molecule preferably includes at least one selected from the group consisting of tripropylene glycol di(meth)acrylate, PO (3 mol)-modified trimethylolpropane triacrylate, PO (3 mol)-modified glyceryl tri(meth)acrylate, PO (4 mol)-modified pentaerythritol tetra(meth)acrylate, PO (4 mol)-modified ditrimethylolpropane tetra(meth)acrylate, and PO (6 mol)-modified dipentaerythritol hexa(meth)acrylate. As commercially available products thereof, TPGDA (tripropylene glycol diacrylate) manufactured by Daicel-Allnex Corporation, Etermer EM 2381 (PO (3 mol) modified trimethylolpropane triacrylate) manufactured by Eternal Materials, OTA-480 (PO (3 mol) modified glyceryl tri(meth)acrylate) manufactured by Daicel-Allnex Corporation, ATM-4P (PO (4 mol) modified pentaerythritol tetraacrylate) and A-DPA-6PA (PO (6 mol) modified dipentaerythritol hexaacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. can be suitably used.

[0066] The electron beam curable composition of the present embodiment may further contain an extender pigment, resin fine particles, and a leveling agent.

[0067] <Extender pigment> The electron beam curable composition of the present embodiment preferably further contains an extender pigment, which improves the film-forming properties of the coating film and increases the coating film strength. 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 alone or in combination of two or more. The preferred extender pigment is silica. The content of the extender pigment is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total amount of the electron beam curable composition.

[0068] <Resin fine particles> The electron beam curable composition of this embodiment preferably further contains resin fine particles, which 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 alone or in combination of two or more, if necessary.

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

[0071] The resin microparticles may be commercially available or may be produced by a known production method. 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 manufactured by Negami Chemical Industrial Co., Ltd. In addition, the urethane resin microparticles may have a crosslinked structure. Specific examples of urethane resin microparticles having a crosslinked structure include crosslinked urethane resin microparticles such as Art Pearl JB-800T, Art Pearl JB-600T, Art Pearl P-800T, and Art Pearl P-400T manufactured by Negami Chemical Industrial Co., Ltd.

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

[0073] Specific examples of acrylic-styrene copolymer resin particles include Eposter 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 JP-A-2014-125495, the fine particles obtained by the production method described in JP-A-2011-26471, and the fine particles obtained by the method described in JP-A-2001-213970.

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

[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 Chemicals Co., Ltd., and Cerafloure 991 manufactured by BYK Japan KK.

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

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

[0079] A specific example of the melamine-benzoguanamine resin fine particles is Eposter M30 manufactured by Nippon Shokubai Co., Ltd.

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

[0081] A specific example of polytetrafluoroethylene resin fine particles is SST-3H-RC manufactured by Shamrock Technologies.

[0082] The resin microparticles are preferably one or more selected from the group consisting of silicone resin microparticles, acrylic resin microparticles, polytetrafluoroethylene resin microparticles, and polyethylene resin microparticles, and more preferably one or more selected from the group consisting of acrylic resin microparticles and polytetrafluoroethylene microparticles. When silicone resin microparticles, acrylic resin microparticles, or polyethylene resin microparticles are used, particle size control is easy, and high sphericity and excellent dispersibility can be easily achieved. Furthermore, these resin microparticles are highly transparent and can provide good slip properties while minimizing loss of gloss. When polytetrafluoroethylene resin microparticles are used, excellent heat resistance and slip properties can be achieved 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 having an average particle size of 1 to 10 μm, more preferably 2 to 6 μm. The resin fine particles may be in the form of particles composed of various resins or particles whose surfaces are coated with various resins. The resin fine particles may be used singly or in combination of two or more types.

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

[0085] <Other ingredients> The electron beam-curable composition in this embodiment may contain resins, antistatic agents, surfactants, antifoaming 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 impaired.

[0086] The electron beam curable composition of this embodiment preferably contains substantially no photopolymerization initiator. By containing substantially no photopolymerization initiator, there is no influence of components derived from the photopolymerization initiator, and gloss, alcohol resistance, abrasion resistance, and low odor are improved. Here, in this specification, "substantially no" means that no component is intentionally added and the content due to unintentional addition is less than 1% by mass. Unintentional addition includes trace amounts contained in each raw material, contamination during the composition production process, and the process of producing printed matter.

[0087] Furthermore, it is preferable that the electron beam-curable composition of this embodiment is substantially free of organic solvents. Organic solvents used as viscosity modifiers in printing inks are likely to contain MOSH / MOAH, which are persistent organic pollutants, and the absence of volatile components (non-VOC) is expected to reduce the environmental load and improve work safety. Therefore, it is preferable that the electron beam-curable composition of this embodiment is substantially free of organic solvents.

[0088] <Viscosity> From the viewpoints of leveling ability and repellency, the electron beam curable composition of this embodiment preferably has a viscosity (25°C, 100 rpm) measured with an E-type viscometer of 1200 mPa·s or less, more preferably 50 to 500 mPa·s, and particularly preferably 100 to 300 mPa·s. If the viscosity (25°C, 100 rpm) of the electron beam curable composition measured with an E-type viscometer is 1200 mPa·s or less, the leveling ability is good and it is easy to control the protruding valley height Svk to 0.8 μm or less. On the other hand, if the viscosity is less than 100 mPa·s, the electron beam curable composition will repell on the substrate, which tends to deteriorate the appearance. If the viscosity is higher than 1200 mPa·s, the leveling ability will decrease, which tends to deteriorate the appearance.

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

[0090] <Production of Overcoat Layer> Examples of methods for printing or coating the electron beam curable composition of this embodiment include 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 (normal lithographic printing using dampening water and waterless lithographic printing not using dampening water), flexo printing, gravure printing, screen printing, etc. In addition, in inline printing and offline printing, various types of inks such as UV curing type, electron beam curing type, heat drying type, evaporation drying type, oxidation polymerization type, penetration drying type, heat polymerization type, two-component curing type, liquid toner type, and powder toner type inks can be used in combination as needed. For the overcoat layer coating, the number of lines is 100 to 500 lines / inch, and the cell capacity is 8 to 20 cm 3 / m 2 By using the above anilox roll, the smoothness of the cured coating film is improved, and it becomes easy to control the protruding 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 was 2 g / m 2 More than 5g / m 2 Preferably, it is 2.5 g / m or less. 2 More than 4.5g / m 2 It is more preferable that the coating amount is 2 g / m or less. 2 More than 5g / m 2 When the coating amount is 2 g / m or less, the smoothness of the overcoat layer is good, making it easy to control the protruding valley height Svk to 0.8 μm or less, resulting in an overcoat layer with good appearance, good alcohol resistance and abrasion resistance, and free from curling or cracking of the coating film due to cure shrinkage. 2 If the coating amount is less than 5g / m, sufficient coating strength cannot be obtained, and alcohol resistance and abrasion resistance tend to deteriorate.2 If the temperature is higher, the coating film tends to curl or crack due to cure shrinkage, and the appearance tends to deteriorate due to reduced 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, and then cured through an electron beam irradiator to form an overcoat layer. The electron beam used for curing is preferably adjusted under conditions of an acceleration voltage of 50 to 200 kV, more preferably 80 to 110 kV, and an exposure dose of 15 to 60 kGy, more preferably 20 to 45 kGy, taking into consideration the balance between damage to the film and the curability of the electron beam-curable composition. An exposure dose of 15 to 60 kGy makes it easy to control the nanoindentation hardness to 50 to 200 MPa, achieving sufficient film strength, while suppressing problems caused by damage to the film, such as a decrease in 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 curing inhibition by oxygen. As a result, electron beam curing is superior to ultraviolet curing in terms of surface curing, and high nanoindentation hardness can be obtained.

[0094] Furthermore, in the laminate of this embodiment, irradiation with an electron beam causes a crosslinking reaction between the layers, resulting in improved adhesion, heat resistance, chemical resistance, etc. This is a phenomenon specific to curing with a high-energy electron beam, and does not occur when curing is performed by irradiation with ultraviolet light. [Example]

[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" means "parts by mass" and "%" means "% by mass."

[0096] <Preparation of Electron Beam-Curable Composition and Ultraviolet-Curable Composition> Details of the materials used are as follows:

[0097] ((Meth)acrylate Compound Having Propylene Oxide as a Structural Unit) TPGDA: Daicel-Allnex TPGDA (tripropylene glycol diacrylate) Miramer M2040: PPG400DA (Polypropylene Glycol Diacrylate) Etermer EM 2381: Eternal Materials, TMP(PO)3TA (PO(3 mol) modified trimethylolpropane triacrylate) OTA-480: Daicel-Allnex Co., Ltd., GPTA (glycerin propoxytriacrylate) NK Ester ATM-4P: Shin-Nakamura Chemical Co., Ltd., PE(PO)4TA (PO (4 mol) modified pentaerythritol tetraacrylate) NK Ester A-DPH-6PA: Shin-Nakamura Chemical Co., Ltd., DPHA(PO)6 (PO(6 mol) modified dipentaerythritol hexaacrylate)

[0098] ((Meth)acrylate Compounds Not Having Propylene Oxide as a Structural Unit) Miramer M122: MIWON, LA (lauryl acrylate) Miramer M280: MIWON, PEG400DA (polyethylene glycol diacrylate) EBECRYL 130: Daicel-Allnex Co., Ltd., TCDDA (tricyclodecane dimethanol diacrylate) Photomer 4028: EO-modified bisphenol A diacrylate manufactured by IGM Miramer M300: MIWON, TMPTA (trimethylolpropane triacrylate) Miramer M3130: MIWON, TMP(EO)3TA (EO (3 mole) modified trimethylolpropane triacrylate) Miramer M3160: MIWON, TMP(EO)6TA (EO (6 mol) modified trimethylolpropane triacrylate) Miramer M3190: MIWON, TMP(EO)9TA (EO (9 mole) modified trimethylolpropane triacrylate) Miramer M3150: MIWON, TMP(EO)15TA (EO (15 mol) modified trimethylolpropane triacrylate) Fancryl FA-731A: Hitachi Chemical Co., Ltd., tris(2-acryloyloxyethyl) isocyanurate Miramer M410: MIWON, DiTMPTA (ditrimethylolpropane tetraacrylate) Miramer M600: Manufactured by MIWON, DPHA (Dipentaerythritol Hexaacrylate) EBECRYL820: Polyester acrylate oligomer manufactured by Daicel Allnex Co., Ltd. EBECRYL8409: Polyurethane acrylate oligomer manufactured by Daicel Allnex Co., Ltd. MIRAMER PE2160: MIWON epoxy acrylate oligomer

[0099] (resin) Beamset 271MS: Arakawa Chemical Industries, Ltd., amino group-containing styrene acrylic resin (extender pigment) AEROSIL R972: Nippon Aerosil Co., Ltd., average primary particle size 16 nm, specific surface area 110 m 2 / g, fumed silica) (Resin fine particles) SST 3H-RC: Shamrock Co., Ltd., average particle size 4.0 μm, polytetrafluoroethylene resin fine particles Cerafloure 991: BYK-Chemie, average particle size 5.0 μm, polyethylene resin fine particles Art Pearl J4PY: Manufactured by Negami Chemical Industrial Co., Ltd., average particle size 2.2 μm, acrylic resin fine particles Tospearl 130: Momentive, average particle size 2.7 μm, silicone resin microparticles (Leveling agent) TEGO Rad 2100: Evonik, polyether-modified polydimethylsiloxane resin with acryloyl groups (Antifoaming agent) BYK-1790: Defoamer manufactured by BYK (Photopolymerization initiator) SB-PI712: 4-methylbenzophenone, manufactured by Sort Daido UV Cure 174: Daido Chemical Industry Co., Ltd., 1-hydroxycyclohexyl phenyl ketone (Photopolymerization initiator aid) Amino alcohol MDA: Nippon Nyukazai Co., Ltd., N-methyldiethanolamine

[0100] (Production Example 1) 97.0 parts of Etermer EM 2381 as a (meth)acrylate compound having propylene oxide as a structural 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 a blending ratio and stirred using a rotation-revolution mixer to obtain an electron beam-curable composition of Production Example 1.

[0101] (Examples 2 to 36) Electron beam-curable compositions of Production Examples 2 to 34 and ultraviolet-curable compositions of Production Examples 35 and 36 were obtained in the same manner as in Production Example 1, except that materials were used according to the compositions shown in Table 1.

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

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

[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 well mixed (pre-dispersed) with a stirrer. Subsequently, this dispersion was carried out using a 0.6 L dyno mill (bead mill manufactured by Shinmaru Enterprises Co., Ltd.) filled with zirconia beads having a diameter of 0.5 mm to obtain a blue aqueous pigment dispersion. [[ID=IO]](Adjustment of Aqueous Inkjet Ink) 20 parts of the above aqueous pigment dispersion, 12 parts of PE1126 (a 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 having 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 (a 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 well mixed (pre-dispersed) with a stirrer. Subsequently, this dispersion was carried out using a 0.6 L dyno mill (bead mill manufactured by Shinmaru Enterprises Co., Ltd.) filled with zirconia beads having a diameter of 0.5 mm to obtain a blue UV pigment dispersion. (Adjustment of UV Inkjet Ink) 10 parts of the above UV pigment dispersion, 40 parts of 2-(2-vinyloxyethoxy)ethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 31.9 parts of phenoxyethyl acrylate, 1 part of dipropylene glycol diacrylate, 6 parts of OMNIRAD819 (a polymerization initiator manufactured by IGM Resins), 6 parts of OMNIRAD TPO H (a polymerization initiator manufactured by IGM Resins), 4.9 parts of KAYACURE DETX-S (a sensitizer manufactured by Nippon Kayaku Co., Ltd.), 0.1 parts of BYK-UV3500 (a siloxane-based surfactant manufactured by BYK), and 0.1 parts of dibutylhydroxytoluene were sequentially added to a mixing vessel. The contents of the mixing vessel were then heated to 50°C and mixed with a stirrer until the polymerization initiator was dissolved. The mixture was then filtered using a depth filter with a pore size of 1 μm to remove coarse particles, yielding a blue UV inkjet ink.

[0106] [Table 1]

[0107] [Table 1]

[0108] [Table 1]

[0109] <Method for producing laminate> The laminate is produced through a process of printing ink on a substrate to form a printed layer, and a process of applying an electron beam curable composition onto the printed layer and irradiating it with electron beams to form an overcoat layer.

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

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

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

[0113] Example 28 A laminate was produced in the same manner as in Example 1, except that white-pigmented PE (SE620L, manufactured by Tamapoly Co., Ltd., thickness 70 μm) was used as the substrate.

[0114] Example 29 A laminate was produced in the same manner as in Example 1, except that a PP seal label (manufactured by UPM Raflatac, FOREST PP WHITE FTC 60, thickness 60 μm) was used as the substrate.

[0115] Example 30 A laminate was produced in the same manner as in Example 1, except that a coated paper seal label (NP Coat PW8E manufactured by Lintec Corporation) was used as the substrate.

[0116] Example 31 A laminate was produced in the same manner as in Example 1, except that a Yupo paper sticker label (Yupo 80 (UV) PW8K Blue, manufactured by Lintec Corporation) was used as the substrate.

[0117] Example 32 A laminate was produced 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 substrate.

[0118] Example 33 A laminate was produced in the same manner as in Example 1, except that the electron beam irradiation dose was 15 kGy.

[0119] Example 34 A laminate was produced in the same manner as in Example 1, except that the electron beam irradiation dose was 60 kGy.

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

[0121] Example 36 (Pre-printed with UV inkjet ink) A laminate was produced in the same manner as in Example 1, except that the printed layer was printed with UV inkjet ink. The UV inkjet ink was printed using a Kyocera KJ4A-RH inkjet head (model KJ4A-RH, design resolution 600 dpi) at a printing speed of 30 m / min and dried using a UV exposure device (GEW 240 W / cm metal halide lamp), resulting in a 100% indigo ink (solid print). The printing conditions were a frequency of 20 kHz, 1200 x 1200 dpi, and a drop volume of 2.5 pL.

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

[0123] (Comparative Examples 11 to 12) (UV curable overcoat) Laminates were produced in the same manner as in Example 1, except that the UV-curable compositions obtained in Production Examples 35 and 36 were used. A UV flexographic printing machine (FA11 manufactured by Nilpeter) was used to apply the UV-curable overcoat. The coating was carried out at a coating speed of 100 m / min, with in-line corona treatment. The anilox roll had a line count of 100 to 500 lines / inch and a cell capacity of 8 to 20 cm. 3 / m 2 The engraved pattern was hexagonal. The printing plate used was a Kodak Flexcel NXH digital flexo plate. For curing, a single GEW E2C mercury UV lamp (air-cooled 140W / cm) was used.

[0124] (Comparative Example 13) (Water-based overcoat) A laminate was produced in the same manner as in Example 1, except that a commercially available water-based overcoat (TW083AQ OP Varnish manufactured by Toyo Ink) was used on the printed layer. A flexographic printing machine (MIRAFLEX CM manufactured by W&H) was used to apply the water-based overcoat. The water-based overcoat was diluted with water using a Zahn Cup No. 4 at 25°C for 10 to 15 seconds before use. Coating was performed using in-line corona treatment at a coating speed of 100 m / min. The anilox roll had a line count of 100 to 500 lines / inch and a cell capacity of 13 to 30 cm. 3 / m 2 The engraving pattern was hexagonal. The printing plate used was a Kodak Flexcel NXH digital flexo plate. Drying was carried out at an interstation dryer temperature of 80°C and a tunnel dryer temperature of 80°C. The coating weight after drying was 2 to 5 g / m 2 The coating was carried out so that the result was as follows.

[0125] (Comparative Example 14) (Solvent-based overcoat) A laminate was produced in the same manner as in Example 1, except that a commercially available solvent-based overcoat (PANNECO AM Medium, manufactured by Toyo Ink) was used on the printed layer. A gravure printing machine was used to apply the solvent-based overcoat. The solvent-based overcoat was diluted with a mixed solvent of ethyl acetate and isopropyl alcohol (70 / 30 by mass) using a Zahn Cup No. 3 at 25°C for 10 to 15 seconds before application. Coating was performed at a speed of 40 m / min, at a drying temperature of 50°C, and a gravure plate with a solid pattern of 30 μm depth was used. The coating weight after drying was 2 to 5 g / m 2 The coating was carried out so that the result was as follows.

[0126] [Table 2]

[0127] [Table 2]

[0128] [Table 2]

[0129] <Various evaluations> The resulting laminate was evaluated as follows. The evaluation results are shown in Table 2.

[0130] (alcohol resistant) The laminates of the examples and comparative examples were rubbed with a cotton swab immersed in 99.5% ethanol solution at a rate of one stroke per second, and the number of strokes until the overcoat layer was scraped off was measured. A rating of 3 or higher is practically preferable. (Evaluation criteria) 5:50 or more times 4: 40 to 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 (based on JIS Z 8741) was measured at a reflection angle of 60° relative to the printed matter using a Micro Trigloss manufactured by BYK. The glossiness of the printed matter was evaluated based on the gloss value according to the following criteria. A rating of 3 to 5 is within the industrially practical range. (Evaluation criteria) 5: Gloss value is 85 or higher 4: Gloss value is 75 or more but less than 85 3: Gloss value is 65 or more but less than 75 2: Gloss value is 55 or more but less than 65 1: Gloss value is less than 55

[0132] (Abrasion resistance) The laminates of the examples and comparative examples were subjected to a rub resistance test using a Gakushin-type rub fastness tester (500 g load, 200 strokes, Kanakin No. 3 rubber (compliant with JIS L0803)) manufactured by Tester Sangyo Co., Ltd., and the scratches on the overcoat layer were evaluated. A rating of 3 to 5 is within the industrially practical range. (Evaluation criteria) 5: No scratches at all 4: The area of ​​the wound is less than 10% 3: The area of ​​the scratch is 10% or more but less than 30% 2: The area of ​​the scratch is 30% or more but less than 50% 1: The area of ​​the wound is 50% or more

[0133] (Odor) Immediately after coating the overcoat layer, the laminate was cut into a 100 mm x 100 mm piece and sealed in a glass bottle. The odor intensity was evaluated by a sensory evaluation by five people, and the average value was used for evaluation. A rating of 3 or higher is practically preferable. (Evaluation criteria) 4: Almost no odor was detected 3: A slight odor was detected 2: The odor was clearly noticeable 1: The odor was strong

[0134] As described above, the laminate (Example) according to 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 digital printing, the overcoat layer is a layer obtained by curing an electron beam-curable composition containing a (meth)acrylate compound with an electron beam, the electron beam-curable composition is substantially free of a photopolymerization initiator, and 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 practical levels. On the other hand, the nanoindentation hardness of Comparative Examples 1 and 7 was less than 50 MPa. As a result, the alcohol resistance and abrasion resistance were insufficient. This is thought to be due to the insufficient crosslink density of the electron beam curable composition. In Comparative Examples 2 to 4, the protruding valley height Svk exceeded 0.8 μm and the nanoindentation hardness was less than 50 MPa. As a result, the gloss and abrasion resistance were insufficient, and in Comparative Examples 2 and 3, the alcohol resistance was also insufficient. This is thought to be due to the fact that the crosslink density of the electron beam curable composition was insufficient, as well as the occurrence of a large number of fine irregularities and pinhole-like defects in the overcoat layer. In Comparative Examples 5, 6, and 8 to 10, the nanoindentation hardness was 50 to 200 MPa, but the protruding valley height Svk exceeded 0.8 μm. As a result, the gloss was insufficient, and in Comparative Example 5, the alcohol resistance was also insufficient. This is thought to be because although the overcoat layer had sufficient hardness and showed good abrasion resistance, a large number of fine irregularities and pinhole-like defects were generated, resulting in a deterioration in gloss in particular. Comparative Example 11 is an ultraviolet-curable overcoat in which some of the (meth)acrylate compounds in Example 1 were replaced with photopolymerization initiators and the like. The protruding valley height Svk was 0.8 μm or less, and the nanoindentation hardness was 50 MPa or more and 200 MPa or less, but the odor was insufficient. This is thought to be due to unreacted photopolymerization initiator and decomposition products of the photopolymerization initiator remaining in the overcoat layer. Furthermore, the alcohol resistance, gloss, and abrasion resistance were also inferior compared to Example 1. With regard to alcohol resistance and abrasion resistance in particular, Comparative Example 11 is ultraviolet-cured, which may be due to surface curing inhibition by oxygen. Another possible reason is that a crosslinking reaction between the ink and the substrate, as occurs when curing with an electron beam, does not occur. Furthermore, this may be due to remaining initiator-derived components. In Comparative Example 12, the overcoat layer was a UV-curable overcoat containing a non-reactive resin and a photopolymerization initiator, and corresponded to the composition described in the examples of Patent Document 1, a prior art document. 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 initiator and decomposition products of the photopolymerization initiator after reaction remaining in the overcoat layer, resulting in insufficient odor. Furthermore, as with Comparative Example 11, this is thought to be due to the deterioration of surface properties specific to UV curing compared to electron beam curing. Furthermore, the inclusion of a non-reactive resin to improve adhesion is thought to have significantly deteriorated alcohol resistance. In Comparative Example 13, the overcoat layer was a water-based overcoat, and the protruding valley height Svk was 0.8 μm or more. As a result, the alcohol resistance, glossiness, and abrasion resistance were insufficient. This is thought to be due to the fact that the water-based overcoat has high surface tension and is easily repelled by the digital printing layer, resulting in the formation of many fine irregularities and pinhole-like defects in the overcoat layer. This is also thought to be due to the fact that evaporation drying is used, so a crosslinking reaction like that of electron beam curable compositions does not occur. In Comparative Example 14, the overcoat layer was a solvent-based overcoat, and the nanoindentation hardness was less than 50 MPa. As a result, the alcohol resistance, glossiness, and abrasion resistance were insufficient. Since the solvent-based overcoat is primarily made of a solvent-soluble, flexible resin, it is believed that the alcohol resistance and abrasion resistance were degraded. Furthermore, the extensive use of resin microparticles to compensate for insufficient surface strength is believed to be the cause of the deterioration in glossiness. Furthermore, this is believed to be due to the fact that evaporation drying is used, and therefore a crosslinking reaction like that of electron beam curable compositions does not occur.

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

Claims

1. A laminate having a substrate, a printing layer, and an overcoat layer in this order, The printed layer is a printed 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 is substantially free of a photopolymerization initiator, The overcoat layer has a protruding valley height Svk defined in ISO 25178 of 0.8 μm or less and a nanoindentation hardness defined in ISO 14577 of 50 to 200 MPa.

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

3. The coating amount of the electron beam curable composition in the overcoat layer is 2 g / m 2 5g / m or more 2 2. The laminate of claim 1, wherein:

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

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

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

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

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

9. A method for producing the laminate according to claim 1, A step of producing a printing layer on a substrate by digital printing; a step of applying an electron beam curable composition onto the print layer and irradiating the composition with an electron beam at an acceleration voltage of 50 to 200 kV and an exposure dose of 15 to 60 kGy to produce an overcoat layer; A method for producing a laminate, comprising:

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