Laminate and packaging bag

Abstract

The invention provides a laminate and a packaging bag. The laminate (10) has a substrate layer (11) comprising a polyolefin resin layer, a sealant layer (12) comprising a polyolefin resin layer, and a printed layer (13) comprising a UV-curable ink or an EB-curable ink. The base material layer (11) and the sealant layer (12) may be bonded to each other with an adhesive layer (14) interposed therebetween. With this laminate (10), it is possible to form a printed layer (13) which has excellent reusability and is stable even without a solvent.

Description

Technical Field

[0001] The present invention relates to a laminate and a packaging bag.

[0002] This application claims priority based on Japanese Patent Application No. 2022-153285 filed in Japan on September 27, 2022, and the contents of which are incorporated herein by reference. Background Art

[0003] Patent Document 1 describes a packaging material in which a substrate is printed with a printing ink such as an oil-based ink or a water-based ink and a heat-fusible film composed of a colored film is laminated, thereby reducing the organic solvent in the solid white printing.

[0004] Patent Document 2 describes a packaging bag having a reinforcement layer formed by coating or sticking a curable resin such as an ultraviolet curable resin, an electron beam curable resin, or a thermosetting resin on a base material of a discharge port.

[0005] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2005-75351 Patent Document 2: Japanese Patent Application Publication No. 2004-338753 Summary of the invention

[0006] Technical issues Regarding the recycling of plastic containers and packaging after use, since packaging bags containing two or more resins are difficult to reuse, it is recommended to use single-material containers and packaging using a single resin. As a single resin, polyethylene resin is cheap and easy to process. However, films and / or pouches using polyethylene resins have problems in forming a stable printing layer because they absorb solvents or are affected by heat during drying.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminate and a packaging bag capable of forming a printed layer that is excellent in recyclability and stable even without a solvent.

[0008] Technical Solution In order to solve the above-mentioned problems, the present invention provides the following aspects.

[0009] The laminated body of the first embodiment has a printed layer composed of a UV curable ink or an EB curable ink on a polyolefin resin layer composed of a polyolefin resin.

[0010] A laminate according to a second aspect is the laminate according to the first aspect, wherein the laminate has two or more polyolefin-based resin layers, and has the printed layer on an outer surface of the laminate or between layers.

[0011] The laminated body according to the third aspect is the laminated body according to the second aspect, wherein the two or more polyolefin-based resin layers include a base layer composed of a polyethylene-based resin layer and a sealant layer.

[0012] A laminate according to a fourth aspect is the laminate according to the third aspect, wherein the base layer is colored milky white.

[0013] A laminate according to a fifth aspect is the laminate according to the third aspect or the fourth aspect, wherein the printed layer is provided on the substrate layer, and the substrate layer is a biaxially stretched film composed of a linear polyethylene resin having a melting point of 130° C. or less.

[0014] The laminated body according to a sixth aspect is any one of the second to fifth aspects, wherein the two or more polyolefin-based resin layers are bonded to each other via an adhesive layer instead of a printed layer.

[0015] A laminate according to a seventh aspect is any one of the second to sixth aspects, wherein the two or more polyolefin-based resin layers are bonded to each other by any one of an extruded resin layer, a solvent-free adhesive layer, and an ultraviolet curable adhesive layer.

[0016] In the packaging bag of the eighth aspect, at least one member is formed of the laminated body of any one of the first to seventh aspects.

[0017] A ninth aspect provides the packaging bag according to the eighth aspect, wherein at least a main body member is formed of the laminated body.

[0018] A packaging bag according to a tenth aspect is the packaging bag according to the eighth aspect or the ninth aspect, wherein the bottom member having the fold line is formed of the laminated body.

[0019] Technical Effects According to the laminated body of the present invention, by including a printed layer composed of a UV curable ink or an EB curable ink, it is possible to form a printed layer that is excellent in recyclability and stable even without a solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a cross-sectional view showing a laminated body according to one embodiment of the present invention.

[0021] Figure 2 This is a front view showing an example of a packaging bag according to an embodiment of the present invention.

[0022] Explanation of symbols 10 ... laminated body, 11 ... base material layer (polyolefin-based resin layer), 12 ... sealant layer (polyolefin-based resin layer), 13 ... printed layer, 14 ... adhesive layer, 100 ... packaging bag, 101 ... main body component, 102 ... bottom component, 103 ... fold line, 104 ... main body sealing portion, 105 ... bottom sealing portion. DETAILED DESCRIPTION

[0023] The preferred embodiment of the present invention is described below. The laminate of this embodiment has a polyolefin resin layer formed of a polyolefin resin, and a printing layer formed on the polyolefin resin layer and composed of a curable ink. The curable ink is a UV curable ink or an EB curable ink.

[0024] The laminate of the embodiment is mainly formed by a polyolefin resin layer with a polyolefin resin as the main body. Therefore, the laminate of the embodiment can realize a container packaging of a single material. The polyolefin resin is not particularly limited as long as it is a polymer with an olefin as the main body, and examples thereof include polyethylene resins, polypropylene resins, etc.

[0025] Figure 1 1 shows a laminate 10 of an embodiment. The laminate 10 includes a substrate layer 11 composed of a polyolefin resin layer, a sealant layer 12 composed of a polyolefin resin layer, and a print layer 13 composed of a curable ink. The print layer 13 in the illustrated example is formed on the outer surface of the laminate 10, but the print layer 13 may also be formed between layers of the laminate 10. The polyolefin resin layer may be one or more layers, or two or more layers. Specifically, the substrate layer 11 and the sealant layer 12 described later may be cited, but are not limited to these.

[0026] UV curable ink is an ink that is cured by UV (ultraviolet light) after printing, and EB curable ink is an ink that is cured by EB (electron beam) after printing. Usually, they contain colorants and polymerizable compounds (monomers, oligomers). Furthermore, resins (polymers) and the like can be added to the ink as needed. Curable ink can form a harder film than thermoplastic resins such as polyolefin resins by curing.

[0027] By laminating the printing layer 13 composed of curable ink on the polyolefin resin layer, printing can be performed without solvent, heating and drying are omitted, and the influence of solvent and heat is suppressed. As a result, even if a polyolefin resin with poor solvent resistance and heat resistance such as polyethylene resin is used for the printing substrate, the restriction of residual solvent and printing substrate can be suppressed. The laminate 10 can have a substrate layer 11 composed of a polyethylene resin layer and a sealant layer 12 composed of a polyethylene resin layer as the polyolefin resin layer. The printing layer 13 can be provided on the outer surface or inner surface of the substrate layer 11 and the outer surface of the sealant layer 12. The printing layer 13 can be provided on a single-layer polyolefin resin film.

[0028] As the polymerizable compound used in the curable ink, any compound can be used as long as it can be polymerized and cure the printed layer 13 when irradiated with ultraviolet rays or electron beams. Since the energy of the electron beam is high, in the case of EB curing, a reaction initiator such as a photoinitiator for UV curing or a thermal initiator for thermal curing is not required. In the case of UV curing, a photoinitiator can be added as needed.

[0029] The polymerizable compound may be a monofunctional monomer having one polymerizable functional group in one molecule, or a polyfunctional monomer having two or more polymerizable functional groups in one molecule, and they may be mixed in an appropriate ratio. Examples of polymerizable functional groups include unsaturated functional groups such as vinyl, allyl, and (meth)acrylate groups. (Meth)acrylate is a general term for acrylate or methacrylate. The curable ink may contain two or more polymerizable compounds.

[0030] Examples of the monofunctional monomer used in the curable ink include acrylamide compounds such as N-acryloylmorpholine, N-vinyl compounds such as N-vinylcaprolactam, and monofunctional (meth)acrylates. Examples of the monofunctional (meth)acrylate include acyclic (meth)acrylates such as alkyl (meth)acrylates, aromatic (meth)acrylates such as benzyl (meth)acrylates, monocyclic (meth)acrylates such as cycloalkyl (meth)acrylates, polycyclic (meth)acrylates such as isobornyl (meth)acrylates, hydroxyl-containing (meth)acrylates such as hydroxyalkyl (meth)acrylates, and ether-containing (meth)acrylates such as alkoxyalkyl (meth)acrylates.

[0031] Examples of the polyfunctional monomer used in the curable ink include divinyl ether compounds, allyl ether compounds, and polyfunctional (meth)acrylates. Examples of the polyfunctional (meth)acrylate include alkylene glycol di(meth)acrylates, polyalkylene glycol di(meth)acrylates, trimethylolpropane tri(meth)acrylates, glycerol tri(meth)acrylates, pentaerythritol tri(meth)acrylates, pentaerythritol tetra(meth)acrylates, and cyclohexanedimethanol di(meth)acrylates.

[0032] As colorants used in curable inks, organic pigments, inorganic pigments, carbon pigments, dyes, etc. can be cited. Curable inks can contain two or more colorants. From the viewpoint of durability, phthalocyanine pigments, quinacridone pigments, metallic lake pigments, rhodamine pigments, azo pigments, carbon black, titanium oxide and other pigments are preferred.

[0033] The resin used in the curable ink is not particularly limited, but preferably has excellent solubility in polymerizable compounds such as (meth)acrylates. Specific examples of the resin used in the curable ink include acrylic resins, alkyd resins, saturated polyester resins, vinyl chloride resins, vinyl acetate resins, maleic acid resins, polyamide resins, urethane resins, epoxy resins, and the like.

[0034] The curable ink may be mixed with desired additives. Examples of the curable ink additives include polymerization inhibitors, dispersants, antioxidants, ultraviolet absorbers, organic solvents, silicones, etc. The curable ink can be printed without solvents and can eliminate residual solvents in polyolefin resins without using volatile organic compounds (VOCs).

[0035] The printed layer 13 can be formed by printing a curable ink in a solid or patterned manner using a printing method such as gravure printing, relief printing, offset printing, screen printing, inkjet printing, etc. and then curing the printed layer 13. The thickness of the printed layer 13 is not particularly limited, but may be about 0.5 to 10 μm.

[0036] The UV curing process of UV curable ink is carried out by irradiating ultraviolet rays toward the ink film on the printed substrate using a light source such as a metal halide lamp or a light emitting diode. The EB curing process of EB curable ink is carried out, for example, by irradiating a beam generated by accelerating electrons at a voltage of about 10 to 100 kV toward the ink film on the printed substrate. In the case of EB curing, in order to suppress polymerization inhibition caused by oxygen (O2) and / or the generation of ozone (O3), it is preferred to irradiate the electron beam in an atmosphere of an inert gas such as nitrogen (N2) or in a reduced pressure atmosphere under vacuum. The curing of curable ink is completed in a short time, and productivity is excellent.

[0037] The printed layer 13 may be formed on the entire surface of the polyolefin resin layer or may be formed on a portion of the surface of the polyolefin resin layer. Two or more printed layers 13 may be overlapped. A plurality of printed layers 13 may be formed of the same type of curable ink or may be a combination of different types of curable inks. Although a transparent protective coating (top coating) may be provided on the printed layer 13, by omitting the protective coating, the ratio of different types of materials can be reduced.

[0038] In order to make the substrate layer 11 forming the printing layer 13 more functional, printing that requires drying may also be performed. The heat resistance of the substrate layer 11 is improved by curing the printing layer 13 composed of curable ink. Therefore, even if printing that requires drying is performed on the substrate layer 11, it can withstand the heat during drying. Solvent-based inks such as water-based inks and oil-based inks can be used for printing that requires drying. The surface on which printing that requires drying is performed may be the inner surface of the substrate layer 11, the outer surface, or both surfaces.

[0039] The base material layer 11 of the laminate 10 may be a stretched polyolefin resin layer or an unstretched polyolefin resin layer, and more specifically, polyethylene resins such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE), polypropylene resins, etc. may be cited. The base material layer 11 may be formed of one polyolefin resin or may contain two or more polyolefin resins.

[0040] The substrate layer 11 may be one layer or two or more layers. When the substrate layer 11 is two or more layers, the resins may be the same or different types of resins. For example, different substrate layers 11 may be formed by using resin layers having different densities, stretching directions, additives, etc. among polyethylene resins, and laminated on the laminate 10. The thickness of the substrate layer 11 is not particularly limited, and for example, about 10 to 50 μm may be cited.

[0041] The base layer 11 may be colored milky white, etc. The base layer 11 may be colored milky white to improve concealment. The printed layer 13 may be provided on the outer surface of the colored base layer 11, or another base layer 11 having the printed layer 13 may be laminated on the outer side of the colored base layer 11.

[0042] When the printed layer 13 is provided on the substrate layer 11, the substrate layer 11 may be a biaxially stretched film composed of a linear polyethylene resin having a melting point of 130° C. or less. A specific example of the linear polyethylene resin is LLDPE. A polyethylene resin having a higher melting point may be used as the substrate layer 11, but even if a polyethylene resin having a lower melting point is used as the substrate layer 11, the printed layer 13 can be formed without a solvent.

[0043] The sealant layer 12 of the laminate 10 is preferably formed of a sealant resin. Examples of the sealant resin include relatively low-density polyethylene resins such as linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), or unstretched polyethylene resins and polypropylene resins. The sealant layer 12 may be formed of one polyolefin resin or may contain two or more polyolefin resins.

[0044] The thickness of the sealant layer 12 is not particularly limited, and for example, it can be about 50 to 180 μm. The sealant layer 12 can be a single-layer sealant film or a multi-layer sealant film. The multi-layer sealant film can be formed by laminating a film-like sealant resin into two or more layers by coextrusion, extrusion lamination, sandwich lamination, thermal lamination, etc.

[0045] The base material layer 11 and the sealant layer 12 may be bonded to each other via an adhesive layer 14. When the base material layer 11 is laminated in two or more layers, the adhesive layer 14 may be used to laminate the layers.

[0046] The adhesive layer 14 may be formed of an adhesive or an anchor coating agent. The material forming the adhesive layer 14 is not particularly limited, and examples thereof include organic titanium compounds such as urethane compounds, epoxy compounds, isocyanate compounds, polyethylene imine, and titanium alkoxides. The thickness of the adhesive layer 14 may be, for example, about 0.1 to 10 μm, about 1 to 6 μm, or about 3 to 4 μm.

[0047] The two or more polyolefin resin layers 11 and 12, such as between the base material layer 11 and the sealant layer 12, can be bonded via the adhesive layer 14 instead of the printed layer 13. Thus, when the polyolefin resin layers 11 and 12 are bonded via the adhesive layer 14, the height difference caused by the printed layer 13 is less likely to occur, and thus the bonding strength can be stabilized.

[0048] In order to bond the layers of the laminate 10, two or more polyolefin resin layers such as between the base layer 11 and the sealant layer 12 can be bonded by any of an extruded resin layer, a solvent-free adhesive layer, and an ultraviolet curing adhesive layer. Compared with the case of using a solvent-based adhesive layer, the influence of the solvent on the polyolefin resin layer and the influence of heat caused by drying can be suppressed.

[0049] As the extruded resin layer, an extruded resin layer of a polyolefin resin can be laminated. Between the layers using the extruded resin layer, the adhesive layer 14 can be omitted. In addition to the substrate layer 11, the sealant layer 12, and the extruded resin layer, the laminate 10 can also have a polyolefin resin layer such as a polyethylene resin layer and a polypropylene resin layer. When laminating the extruded resin layer, the resin film or the extruded resin in a molten state can be subjected to surface treatment such as corona treatment, plasma treatment, and ozone treatment.

[0050] When an extruded resin layer is used to bond polyolefin resin layers, the melting point of the resin used in the extruded resin layer is preferably the same as or lower than the melting point of the resin used in the polyolefin resin layer. For example, a polyethylene resin layer is preferably used as an extruded resin layer bonding polyethylene resin layers, and a polypropylene resin layer is preferably used as an extruded resin layer bonding polypropylene resin layers.

[0051] Examples of the solvent-free adhesive layer include an adhesive layer 14 using a solvent-free adhesive such as an acrylic adhesive, a polyvinyl acetate adhesive, a polyamide adhesive, a polyether adhesive, a polyester adhesive, an epoxy adhesive, a polyurethane adhesive, a silicone adhesive, or a cyanoacrylate adhesive.

[0052] Examples of the ultraviolet curable adhesive layer include an adhesive layer 14 using an ultraviolet curable adhesive containing a photopolymerizable compound, a photoinitiator, a photosensitizer, etc. Examples of the photopolymerizable compound include photoradical polymerizable compounds such as acrylates and vinyl ethers, and photocationic polymerizable compounds such as epoxy compounds and oxetane compounds.

[0053] When the laminate 10 has a plurality of polyolefin resin layers in the base material layer 11, the sealant layer 12, the extruded resin layer, etc., all of the polyolefin resin layers may be polyethylene resin layers, or all of the polyolefin resin layers may be polypropylene resin layers. In the same laminate 10, two or more polyolefin resin layers having different main component monomers of the polyolefin resin may be mixed and laminated.

[0054] Here, the main component monomer in the polyolefin resin is the monomer with the largest weight ratio in the resin. For example, the main component monomer of the polyethylene resin is ethylene, and the main component monomer of the polypropylene resin is propylene. In the case of a homopolymer, this monomer becomes the main component monomer. In addition, the main component resin in the polyolefin resin layer is the resin with the largest weight ratio in the resin layer.

[0055] In the polyethylene resin layer, the proportion of the polyethylene resin is preferably 50% by weight or more, and may also be 80 to 100% by weight. The polyethylene resin may be a homopolymer of ethylene or a copolymer based on ethylene. As monomers (comonomers) other than ethylene, one or more of α-olefins such as 1-butene, 1-hexene, and 1-octene, cyclic olefins such as norbornene, vinyl acetate, vinyl chloride, acrylic acid, and the like may be cited. In the case of copolymerization of a polyethylene resin with a monomer having an ester group such as vinyl acetate, a portion of the ester group may be saponified to form a copolymer containing vinyl alcohol.

[0056] The proportion of ethylene in the constituent monomers of the polyethylene resin is preferably 50% by weight or more, for example, 80 to 100% by weight. The ethylene or comonomer used in the polyethylene resin may be a compound derived from fossil resources such as petroleum, or a compound derived from biomass such as plants. The resin contained in the polyethylene resin layer may be only a polyethylene resin, or may contain other resin components. The polyethylene resin may be one, or a blend of two or more, and may include recycled polyethylene.

[0057] In the polypropylene resin layer, the proportion of the polypropylene resin is preferably 50% by weight or more, and may also be 80 to 100% by weight. As the polypropylene resin, it may be a homopolymer of propylene (homopolymer PP), or a random copolymer (random PP) or a block copolymer (block PP) in a propylene-ethylene copolymer or the like. As monomers (comonomers) other than propylene, α-olefins such as ethylene, 1-butene, 1-hexene, and 1-octene, vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid may be listed. The comonomers of the polypropylene resin may be one or more.

[0058] The proportion of propylene in the constituent monomers of the polypropylene resin is preferably 50% by weight or more, for example, 80 to 100% by weight. The propylene or comonomer used in the polypropylene resin may be a compound derived from fossil resources such as petroleum, or a compound derived from biomass such as plants. The resin contained in the polypropylene resin layer may be only a polypropylene resin, or may contain other resin components. The polypropylene resin may be one type, or a blend of two or more types, and may include recycled polypropylene.

[0059] The resin contained in the polyolefin resin layer such as the substrate layer 11 and the sealant layer 12 may be only a polyolefin resin, only a polyethylene resin, or only a polypropylene resin, or may contain other resin components, or may contain additives other than the resin. The additive is not particularly limited, and examples thereof include antioxidants, lubricants, anti-blocking agents, flame retardants, ultraviolet absorbers, light stabilizers, antistatic agents, colorants, crosslinking agents, etc. The additive may be a component compatible with the resin or a component incompatible with the resin.

[0060] At least a part of the polyolefin resin may include recycled polyolefin resin. The method of recycling the polyolefin resin is not particularly limited, and may be chemical recycling in which the used resin is decomposed into monomers and then polymerized again, or mechanical recycling in which the used resin is kept in a polymer state and regenerated through processes such as crushing and screening. The recycled resin may be mixed with new resin for use.

[0061] With respect to the total weight of the laminate 10 of the above-mentioned embodiment, it is preferred that the total amount of the specific resin is 90% by weight or more and the total amount of materials other than the specific resin is 10% by weight or less, and it is more preferred that the total amount of the specific resin is 95% by weight or more and the total amount of materials other than the specific resin is 5% by weight or less. Thus, even if a curable ink, adhesive, etc. are used in the laminate 10, a single material of the specific resin can be achieved. As the specific resin, for example, any one of a polyolefin resin, a polyethylene resin, or a polypropylene resin can be cited. The laminate 10 can use two or more resins corresponding to the specific resin.

[0062] The laminate 10 of the above embodiment is a laminated film mainly composed of a polyolefin resin such as a polyethylene resin, and can be used for various purposes. The method of forming the laminated film is not particularly limited, and examples thereof include dry lamination, extrusion lamination, heat lamination, coextrusion, coating, etc. Different methods can be used to laminate each layer. The sealant layers can be made to face each other and the laminate can be joined by welding.

[0063] The laminate 10 of the embodiment can be used for making packaging bodies such as packaging bags. At least one part of the packaging body can be formed by the laminate 10, and other parts can be, for example, a film without a printed layer 13. The use of the packaging body is not particularly limited to disposable use, repacking, storage, storage of articles, etc., but is suitable for use with sealed liquids, and is particularly suitable for use in which the main container used when the contents are consumed is refilled once or multiple times. In this case, the main container can withstand long-term use, and the packaging of the refill container can be simplified. In addition, when the refill container is disposed of after the contents are used up, it becomes easy to reuse.

[0064] Examples of the packaging body include packaging bags such as pouches and bags, tubes, containers, sleeve packaging, strip packaging, and lidding materials. Specific examples of packaging bags include three-side sealed bags, four-side sealed bags, pillow bags, gusseted bags, and self-supporting bags. When the laminate is a soft laminate film, a flexible packaging body can be formed.

[0065] Figure 2 1 shows an example of a packaging bag that becomes a self-supporting bag. The packaging bag 100 is formed by a pair of main body parts 101 and a bottom part 102 folded in half at a fold line 103. The main body parts 101 are arranged one at the front and one at the back. The planar shapes of the front and rear main body parts 101 can be the same. The bottom part 102 is folded in at the fold line 103 so that the outer surfaces face each other. At a position above the fold line 103, a main body sealing part 104 is formed on the left and right, and the inner surfaces of the front and rear main body parts 101 are joined to each other.

[0066] The bottom member 102 is sandwiched between the front and rear main body members 101 so that the fold line 103 is located on the upper side. A bottom seal 105 is formed below the fold line 103 to join the inner surface of the bottom member 102 to the inner surface of the main body member 101. The bottom seal 105 joins the regions of the bottom member 102 divided by the fold line 103 to the main body member 101 on the same side in the front-back direction. The bottom member 102 is unfolded relative to the fold line 103, so that the packaging bag 100 can stand on its own.

[0067] When the packaging bag 100 has a main body 101 and a bottom member 102, the laminate 10 of the embodiment can be used for either or both of the main body 101 and the bottom member 102. By using the laminate 10 having the printed layer 13 using a curable ink on the main body 101 or the bottom member 102, an image including a pattern, text, etc. can be displayed on the surface of the packaging bag 100.

[0068] After the printed layer 13 is formed on the outer surface of the area of ​​the main body member 101 where the main body seal 104 or the bottom seal 105 is to be formed, the main body member 101 may be heated from the outer surface side to form the main body seal 104 or the bottom seal 105. This can prevent the main body member 101 from sticking to heat-sealing components such as sealing strips.

[0069] The packaging bag 100 may have a filling port, a discharge port, and the like. For example, an opening may be formed between the front and rear main body parts 101 at the upper portion of the packaging bag 100, and may be used for filling or discharging the contents. After the contents are filled, the main body parts 101 may be joined to seal the packaging bag 100. When the packaging bag 100 is opened, the joined portion between the main body parts 101 may be easily torn open. Although not specifically shown in the figure, the discharge port may also be formed in a shape that protrudes thinly at the upper portion of the packaging bag 100 or at a corner. The discharge port may be a film-molded or nozzle-shaped.

[0070] The size of the package is not particularly limited. For example, in the case of a heavy-duty container, the height in the vertical direction is about 100 to 500 mm, the width in the horizontal direction is about 70 to 300 mm, and the filling volume is 100 cm 3 ~5000cm 3 The state of the contents is not particularly limited, and examples thereof include fluids such as liquids, powders, and particles, or solid substances such as articles. The types of the contents are not particularly limited, and examples thereof include detergents, medicaments, cosmetics, pharmaceuticals, beverages, seasonings, inks, coatings, fuels, and the like.

[0071] The package may be formed only of the laminate 10 of the embodiment, or may be combined with an accessory such as a label, a sticker, a straw, an outer box, etc. From the viewpoint of recycling, it is preferred that the accessory can be separated from the package. In order to facilitate the opening of the package, an easy-to-open unit such as a perforated line, a notch, a half-cut groove, etc. may be formed around the opening portion.

[0072] The method for recycling the laminate 10 or packaging bag 100 after using the embodiment is not particularly limited, and can be appropriately selected according to the state at the time of recycling, etc. The laminate 10 of the embodiment can increase the proportion of polyolefin resin, so any of the above-mentioned chemical recycling and mechanical recycling can be performed. By recycling the laminate 10 or packaging bag 100 of the embodiment, it can also be recycled into a product of the same type as the laminate 10 or packaging bag 100. The recycled material can be used for products such as coatings, molded products, hydrocarbon oils, etc.

[0073] The present invention has been described above based on preferred embodiments, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention. Examples of the changes include addition, replacement, omission, and other modifications of constituent elements.

[0074] [Example] Hereinafter, examples of the present invention will be described in detail, but the present invention is not limited to these examples.

[0075] In Example 1, EB offset printing using EB curing ink was used, in Example 2, UV printing using UV curing ink was used, in Comparative Example 1, oily gravure printing using oily ink was used, and in Comparative Example 2, water-based flexographic printing using water-based ink was used to form a printing layer on the printing substrate.

[0076] In the residual solvent test, uniaxially stretched HDPE was used as the printing substrate. Gas chromatography was used to confirm whether an organic solvent was detected in the printing substrate after printing, and the case where no residual solvent was detected was evaluated as good (○), and the case where residual solvent was detected was evaluated as bad (×).

[0077] In the printing test (multi-color printing, spacing), the printing substrate was set to three types: uniaxially stretched HDPE, unstretched HDPE, and biaxially stretched LLDPE. While the printing substrate was conveyed in a roll-to-roll manner, a multi-color printed layer was formed at a predetermined spacing. The case where the spacing was accurate was evaluated as good (○), the case where the spacing was slightly inaccurate was evaluated as slightly poor (△), and the case where the spacing was even more inaccurate was evaluated as poor (×).

[0078]

Table 1

[0079] As shown in Table 1, since oil-based ink was used in Comparative Example 1, residual solvent was detected. The results of multi-color printing in Comparative Examples 1 and 2 were deteriorated due to the influence of heat drying. In Examples 1 and 2, since it is not necessary to dry the ink, it is not limited to using uniaxially stretched HDPE with a high elastic modulus as the printing substrate. Even if unstretched HDPE or biaxially stretched LLDPE is used as the printing substrate, the pitch can be accurately reproduced.

[0080] Industrial Applicability According to the present invention, by including a printed layer made of UV curable ink or EB curable ink, it is possible to form a printed layer that is excellent in recyclability and stable even without a solvent. Therefore, the present invention can be used industrially.

Claims

1. A laminate, characterized in that: A printed layer made of UV curable ink or EB curable ink is provided on the polyolefin resin layer formed of the polyolefin resin.

2. The laminate according to claim 1, characterized in that The laminate has two or more polyolefin-based resin layers, and has the printed layer on the outer surface or between the layers of the laminate.

3. The laminate according to claim 2, characterized in that The two or more polyolefin-based resin layers include a base layer composed of a polyethylene-based resin layer and a sealant layer composed of a polyethylene-based resin layer.

4. The laminate according to claim 3, characterized in that The substrate layer is colored milky white.

5. The laminate according to claim 3, characterized in that The printed layer is provided on the base layer, and the base layer is a biaxially stretched film composed of a linear polyethylene resin having a melting point of 130° C. or less.

6. The laminate according to claim 2, characterized in that The two or more polyolefin-based resin layers are bonded to each other via an adhesive layer instead of a printed layer.

7. The laminate according to claim 2, characterized in that: The two or more polyolefin-based resin layers are bonded to each other by any one of an extrusion resin layer, a solvent-free adhesive layer, and an ultraviolet curing adhesive layer.

8. A packaging bag, characterized in that: At least one component is formed of the laminated body according to any one of claims 1 to 7.

9. The packaging bag according to claim 8, characterized in that: At least the main body member is formed from the laminated body.

10. The packaging bag according to claim 8, characterized in that: A bottom member having fold lines is formed from the laminate.

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