Laminate and package

Abstract

To provide a laminate and a package, capable of exhibiting recyclability, barrier performance, and adhesiveness simultaneously.SOLUTION: A laminate 10 has two or more polyolefin-based resin layers composed of a polyolefin-based resin. At least one portion of the polyolefin-based resin layers is adhered using an epoxy adhesive 13. A printing layer 14 is laminated at a portion not adjacent to the epoxy adhesive 13.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In paragraph 0010 of Patent Document 1, as a film conventionally used for packaging bags, a laminated film in which a polyolefin resin such as low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, or polypropylene is laminated as a sealant layer on a base film such as biaxially stretched polypropylene, biaxially stretched polyamide, or biaxially stretched polyester is described. Examples of methods for manufacturing the laminated film include a dry lamination method, an extrusion lamination method, and a coextrusion method.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, regarding the recycling of plastic container packaging after use, there is a problem that a packaging bag containing two or more types of resins is difficult to recycle as plastic container packaging. In order to facilitate recycling, a monomaterial container packaging using a single resin has been proposed. As a single resin, a polyethylene-based resin is inexpensive and easy to process. However, when a packaging bag is formed from a film using only polyethylene, the barrier properties decrease. In addition, depending on the barrier material, the adhesion between the layers of the laminate may decrease.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a laminate and a package capable of having recyclability, barrier properties, and adhesion.

Means for Solving the Problems

[0006] The present invention includes the following aspects. A first aspect is a laminate having two or more polyolefin resin layers formed from a polyolefin resin, wherein at least one portion of the polyolefin resin layer is adhered using an epoxy-based adhesive, and a printing layer is laminated at a location not adjacent to the epoxy-based adhesive.

[0007] A second aspect is the laminate according to the first aspect, wherein the laminate has a sealant layer and a base material layer made of a polyethylene resin layer as the polyolefin resin layer, and the interface between the sealant layer and the base material layer is adhered via the epoxy-based adhesive, and the printing layer is laminated on the outer surface of the base material layer.

[0008] A third aspect is the laminate according to the first aspect, wherein the laminate has a sealant layer, a first base material layer, and a second base material layer made of a polyethylene resin layer as the polyolefin resin layer, and one of the interfaces between the sealant layer and the first base material layer and between the first base material layer and the second base material layer is adhered via a urethane-based adhesive, and the other of the interfaces between the sealant layer and the first base material layer and between the first base material layer and the second base material layer is adhered via the epoxy-based adhesive, and the printing layer is laminated on the outer surface of the second base material layer.

[0009] A fourth aspect is the laminate according to the first aspect, wherein the laminate has a sealant layer, a first base material layer, and a second base material layer made of a polyethylene resin layer as the polyolefin resin layer, and one of the interfaces between the sealant layer and the first base material layer and between the first base material layer and the second base material layer is adhered via the epoxy-based adhesive, and in the other of the interfaces between the sealant layer and the first base material layer and between the first base material layer and the second base material layer, the printing layer and the urethane-based adhesive layer may be formed in any order.

[0010] The fifth aspect is that in any one of the first to fourth aspects, the epoxy-based adhesive consists of an epoxy-based main agent and an amide-based curing agent. The sixth aspect is a package formed from the laminate of any one of the first to fifth aspects.

Advantages of the Invention

[0011] According to the present invention, in a laminate and a package mainly composed of a polyolefin-based resin film such as a polyethylene-based resin, by using an epoxy-based adhesive, it is possible to achieve both recyclability and barrier properties. Further, by laminating a printing layer at a location not adjacent to the epoxy-based adhesive, adhesion can be ensured.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described based on preferred embodiments. The laminate of the embodiment is a laminate having two or more polyolefin-based resin layers formed from a polyolefin-based resin, at least one location of the polyolefin-based resin layer being adhered using an epoxy-based adhesive, and a printing layer being laminated at a location not adjacent to the epoxy-based adhesive. The epoxy-based adhesive can be formed from an epoxy-based resin composition.

[0014] An epoxy resin composition uses an epoxy-based main agent. The epoxy-based main agent is not particularly limited, and examples include compounds having an epoxy group in the molecule, such as aromatic epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, and heterocyclic epoxy resins. Specific examples of the epoxy-based main agent include bisphenol-type epoxy resins, novolak-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ether-type epoxy resins, glycidyl ester-type epoxy resins, modified epoxy resins, and triglycidyl isocyanurate.

[0015] A copolymer containing an epoxy group-containing vinyl monomer may also be used as the epoxy-based main agent. Examples of the epoxy group-containing vinyl monomer include glycidyl esters such as glycidyl methacrylate (GMA) and glycidyl acrylate, glycidyl ethers such as allyl glycidyl ether, and epoxy alkenes such as epoxybutene. Examples of the other monomers copolymerized with the epoxy group-containing vinyl monomer include olefins such as ethylene and propylene, acrylic monomers such as (meth)acrylate esters, and vinyl monomers such as vinyl acetate.

[0016] A curing agent is used in the epoxy resin composition. Examples of the curing agent include amine-based curing agents, acid anhydride-based curing agents, imidazole compounds, and amide-based curing agents. Examples of the amine-based curing agent include primary amines, secondary amines, tertiary amines, aliphatic amines, and aromatic amines. Examples of the acid anhydride-based curing agent include aromatic acid anhydrides, aliphatic acid anhydrides, and alicyclic acid anhydrides. The imidazole compound may have a substituent such as an alkyl group or may be in the form of salts such as carboxylates.

[0017] The amide-based curing agent is not particularly limited as long as it is a curing agent having an amide group that can be used for the epoxy-based main agent. Generally, polyamide resins (polyaminoamide compounds) produced by the condensation of polycarboxylic acids and polyamines are mentioned. Amide-based compounds such as dicyandiamide (cyanoguanidine) and biguanide compounds that are derivatives of dicyandiamide may also be used as the curing agent.

[0018] Examples of the polycarboxylic acid used in the polyamide resin include dicarboxylic acids such as adipic acid and tricarboxylic acids. As these polycarboxylic acids, polymerized fatty acids such as dimer acid and trimer acid are preferred. Examples of the polyamine used in the polyamide resin include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylene polyamine, ethylenediamine, piperazine, diaminopropane, diaminobutane, diaminopentane, diaminohexane, polyoxyalkylene polyamine, and the like.

[0019] The epoxy resin composition preferably consists of an epoxy-based main agent and an amide-based curing agent. Compared with other curing agents, the amide-based curing agent can obtain a cured product in which the epoxy resin is plasticized after curing, and has excellent durability against tension, compression, bending, impact, etc. Therefore, it is suitable as an adhesive used for a laminated film of a flexible polyethylene-based resin. Since a dense cured film can be obtained, the barrier property of the laminate can be improved.

[0020] Next, with reference to FIG. 1, the laminate 10 of the first embodiment will be described. The laminate 10 has a sealant layer 11 formed of a polyolefin-based resin and a base material layer 12 formed of a polyolefin-based resin. The interface between the sealant layer 11 and the base material layer 12 is adhered through an epoxy-based adhesive 13, and a printing layer 14 is laminated on the outer surface of the base material layer 12. By laminating the printing layer 14 at a location not adjacent to the epoxy-based adhesive 13, adhesion can be ensured.

[0021] The sealant layer 11 is preferably formed of a sealant resin. Examples of the sealant resin include relatively low-density polyethylene-based resins such as linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), or unstretched polyethylene-based resins, polypropylene-based resins, and the like. The sealant layer 11 may be formed of one type of polyolefin-based resin or may contain two or more types of polyolefin-based resins.

[0022] The thickness of the sealant layer 11 is not particularly limited, and for example, it may be about 50 to 180 μm. The sealant layer 11 may be a single-layer sealant film or a multi-layer sealant film. The multi-layer sealant film can be formed by laminating two or more layers of film-like sealant resin by a co-extrusion method, an extrusion lamination method, a sandwich lamination method, a thermal lamination method, or the like.

[0023] The base material layer 12 may be a stretched polyolefin resin layer or an unstretched polyolefin resin layer. Examples of the base material layer 12 include relatively high-density polyethylene resins such as medium-density polyethylene (MDPE) and high-density polyethylene (HDPE), and polypropylene resins. The base material layer 12 may be formed from one type of polyolefin resin or may contain two or more types of polyolefin resins. The thickness of the base material layer 12 is not particularly limited, and for example, it may be about 10 to 50 μm.

[0024] The polyethylene resin used in the polyethylene resin layer such as the sealant layer 11 and the base material layer 12 may be a homopolymer of ethylene or a copolymer mainly composed of ethylene. Examples of monomers (comonomers) other than ethylene include one or more of α-olefins such as 1-butene, 1-hexene, and 1-octene, cyclic olefins such as norbornene, and vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid. When a comonomer is used in the polyethylene resin, the comonomer may be one type or two or more types.

[0025] The proportion of ethylene in the constituent monomers of the polyethylene-based resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The ethylene or comonomer used in the polyethylene-based 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-based resin layer may be only the polyethylene-based resin, or may contain other resins. The material forming the polyethylene-based resin layer may be one kind of polyethylene-based resin, or a blend of two or more kinds of polyethylene-based resins. The polyethylene-based resin layer may contain recycled polyethylene.

[0026] A polypropylene (PP)-based resin may be used for the sealant layer 11 or the base material layer 12. The polypropylene-based resin may be a homopolymer of propylene (homo-PP), or a random copolymer (random-PP) or a block copolymer (block-PP) in a propylene-ethylene copolymer or the like. Examples of monomers (comonomers) other than propylene include one or more of α-olefins such as ethylene, 1-butene, 1-hexene, and 1-octene, and vinyl-based monomers such as vinyl acetate, vinyl chloride, and acrylic acid. When a comonomer is used in the polypropylene-based resin, the comonomer may be one kind or two or more kinds. The proportion of propylene in the constituent monomers of the polypropylene-based resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The polypropylene-based resin layer may contain recycled polypropylene.

[0027] The resin contained in the sealant layer 11 or the base material layer 12 may be only a polyolefin-based resin, only a polyethylene-based resin, or only a polypropylene-based resin, or may contain other resins. The polyolefin-based resin layers such as the sealant layer 11 and the base material layer 12 may contain additives other than the resin. The additives are not particularly limited, and examples thereof include antioxidants, lubricants, antiblocking agents, flame retardants, ultraviolet absorbers, light stabilizers, antistatic agents, colorants, crosslinking agents, and the like. The additives may be components compatible with the resin or components incompatible with the resin.

[0028] In the first embodiment, the epoxy-based adhesive 13 forms an adhesive layer between the sealant layer 11 and the base material layer 12. The adhesive layer may be an epoxy-based adhesive layer. The thickness of the epoxy-based adhesive 13 is, for example, about 0.1 to 10 μm, about 1 to 6 μm, or about 3 to 4 μm. The lamination of the sealant layer 11 and the base material layer 12 via the epoxy-based adhesive 13 can be carried out by a dry lamination method.

[0029] Next, with reference to FIG. 2, the laminate 20 of the second embodiment will be described. In this laminate 20, a sealant layer 11, a first base material layer 15, and a second base material layer 16, each formed of a polyolefin-based resin such as a polyethylene-based resin, are laminated via an epoxy-based adhesive 13 and a urethane-based adhesive 17, respectively. A printing layer 14 is laminated on the outer surface of the second base material layer 16. By laminating the printing layer 14 at a location not adjacent to the epoxy-based adhesive 13, adhesion can be ensured.

[0030] The urethane-based adhesive 17 in the illustrated example is an adhesive layer that adheres between the sealant layer 11 and the first base material layer 15. The adhesive layer may be a urethane-based adhesive layer. Further, the epoxy-based adhesive 13 is an adhesive layer that adheres between the first base material layer 15 and the second base material layer 16. Although not particularly shown, an epoxy-based adhesive 13 may be laminated between the sealant layer 11 and the first base material layer 15, and a urethane-based adhesive 17 may be laminated between the first base material layer 15 and the second base material layer 16. By having a urethane-based adhesive 17 on one side and an epoxy-based adhesive 13 on the other side of the two layers, both barrier properties and adhesion can be achieved.

[0031] The laminate 20 of the second embodiment has a first base material layer 15 and a second base material layer 16 instead of the base material layer 12, and can be manufactured in the same manner as the laminate 10 of the first embodiment except that an epoxy-based adhesive 13 and a urethane-based adhesive 17 are used at two interfaces respectively. The materials of the first base material layer 15 and the second base material layer 16 may be the same as those of the base material layer 12 of the first embodiment. In addition, the thickness of the adhesive layer using the urethane-based adhesive 17 is, for example, about 0.1 to 10 μm, about 1 to 6 μm, or about 3 to 4 μm.

[0032] Adhesives other than the epoxy-based adhesive 13 are not particularly limited, but as a general adhesive, a urethane-based adhesive 17 may be used. Thereby, in the urethane-based adhesive 17 in contact with the sealant layer 11, importance can be attached to the adhesion to the first base material layer 15. An epoxy-based adhesive 13 may be used between the first base material layer 15 and the second base material layer 16 near the outer surface of the laminate 20 in order to emphasize the barrier property. Since the sealant layer 11 is a layer that is heated and melted when the laminate 20 is heat-sealed, it is preferable to use an adhesive with high adhesion reliability.

[0033] When the laminate 20 is formed into a bag, in the case of contents that permeate through the sealant layer 11 and affect the adhesive, reducing the adhesive strength, using the epoxy-based adhesive 13 between the sealant layer 11 and the first base material layer 15 improves the barrier property and suppresses the influence on the adhesive. At this time, a urethane-based adhesive 17 can be used between the first base material layer 15 and the second base material layer 16.

[0034] Next, with reference to FIG. 3, the laminate 30 of the third embodiment will be described. In this laminate 30, a sealant layer 11, a first base material layer 15, and a second base material layer 16, each formed of a polyolefin-based resin such as a polyethylene-based resin, are laminated via an epoxy-based adhesive 13 and a urethane-based adhesive 17 respectively. An epoxy-based adhesive 13 is laminated between the sealant layer 11 and the first base material layer 15, and a urethane-based adhesive 17 is laminated between the first base material layer 15 and the second base material layer 16.

[0035] Furthermore, a printing layer 14 is laminated on the inner surface of the second base material layer 16 and is in contact with the urethane-based adhesive 17. By laminating the printing layer 14 at a location not adjacent to the epoxy-based adhesive 13, adhesion can be ensured. The interface between adjacent polyolefin-based resin layers is not limited to the interface between the first base material layer 15 and the second base material layer 16. The printing layer 14 may be in contact with the urethane-based adhesive 17 at the interface between the first base material layer 15 and the sealant layer 11. The configuration other than the position of the printing layer 14 in the third embodiment may be the same as that in the second embodiment.

[0036] In the illustrated example, the order is "first base material layer 15 / urethane-based adhesive 17 / printing layer 14 / second base material layer 16". The arrangement order of the printing layer and the urethane-based adhesive layer may be arbitrary. For example, although not particularly illustrated, the order may be "first base material layer 15 / printing layer 14 / urethane-based adhesive 17 / second base material layer 16" or "first base material layer 15 / urethane-based adhesive 17 / printing layer 14 / urethane-based adhesive 17 / second base material layer 16". Also, in the interface between adjacent polyolefin-based resin layers, two or more printing layers 14 may be provided, and further, the number of layers of the urethane-based adhesive 17 may be increased.

[0037] Of the two interfaces included in the laminate 30, one is formed using the urethane-based adhesive 17 and the other is formed using the epoxy-based adhesive 13. Thereby, both barrier properties and adhesion can be achieved.

[0038] When emphasizing the adhesion at the interface between the sealant layer 11 and the first base material layer 15, the urethane-based adhesive 17 may be used at the interface between the sealant layer 11 close to the inner surface of the laminate 30 and the first base material layer 15, and the epoxy-based adhesive 13 may be used at the interface between the first base material layer 15 and the second base material layer 16 close to the outer surface of the laminate 30. At the interface in contact with the sealant layer 11, it is preferable to use an adhesive with high adhesion reliability. In this case, the printing layer 14 may be laminated on the inner surface of the first base material layer 15.

[0039] When the laminate 30 is made into a bag, in the case of contents that permeate through the sealant layer 11 and affect the adhesive, reducing the adhesive strength, if an epoxy-based adhesive 13 is used between the sealant layer 11 and the first base material layer 15, the barrier property is improved and the influence on the adhesive is suppressed. At this time, a urethane-based adhesive 17 can be used between the first base material layer 15 and the second base material layer 16 close to the outer surface of the laminate 30 so as to be in contact with the printing layer 14.

[0040] The printing layer 14 can be formed by printing ink in a solid or patterned state by printing methods such as gravure printing, letterpress printing, offset printing, screen printing, and inkjet printing. The thickness of the printing layer 14 is not particularly limited, but is about 0.5 to 10 μm. The printing layer 14 may be formed on the entire surface of the laminates 10, 20, 30, or may be formed on a part of the in-plane. Two or more printing layers 14 may be laminated.

[0041] The ink for forming the printing layer 14 may contain a coloring material such as a pigment or a dye, and a binder. The binder is not particularly limited, and examples thereof include polyamide, polyurethane, polyester, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, acrylic polymer, polybutadiene, and cyclized rubber. The ink may contain a solvent such as water, an organic solvent, or vegetable oil. After printing, the ink can be dried by volatilization of the solvent, curing of the ink, or the like. In order to accelerate the drying of the ink, heating, ultraviolet irradiation, or the like may be performed.

[0042] To manufacture the laminate 30 of the third embodiment, for example, after laminating the printing layer 14 and the urethane-based adhesive 17 on one side of the second base material layer 16 using a printing method, a method of bringing the second base material layer 16 having the urethane-based adhesive 17 and the printing layer 14 on one side into close contact with the first base material layer 15 can be mentioned. According to this method, since the urethane-based adhesive 17 and the printing layer 14 can be laminated on the second base material layer 16 serving as the base material layer using a printing method, productivity can be improved. It should be noted that it is also possible to form the printing layer 14 on the first base material layer 15.

[0043] It is preferable that the total of the specific resin is 90% by weight or more and the total of materials other than the specific resin is 10% by weight or less with respect to the total weight of the laminates 10, 20, and 30 of the above embodiments. More preferably, the total of the specific resin is 95% by weight or more and the total of materials other than the specific resin is 5% by weight or less. Thereby, even if an adhesive or the like is used in the laminates 10, 20, and 30, a monomeric material of the specific resin can be realized. Examples of the specific resin include any one of polyolefin resins, polyethylene resins, and polypropylene resins. The laminates 10, 20, and 30 may use two or more resins corresponding to the specific resin.

[0044] The laminates 10, 20, and 30 of the above embodiments are in the form of a laminated film mainly composed of a polyolefin resin such as a polyethylene resin and can be used for various applications. The method for forming the laminated film is not particularly limited, and examples include dry lamination, extrusion lamination, thermal lamination, coextrusion, coating, and the like. Different methods may be used to laminate each layer. The laminates can be joined by fusion with the sealant layers facing each other.

[0045] The adhesive used for dry lamination of the laminated film is not limited to the adhesives exemplified for the epoxy adhesive 13 and the urethane adhesive 17 in the first to third embodiments, and other adhesives may be used. Although not particularly limited, examples of the adhesive include urethane compounds, epoxy compounds, isocyanate compounds, polyethyleneimine, and organic titanium compounds such as titanium alkoxides. The thickness of the adhesive layer is, for example, about 0.1 to 10 μm, about 1 to 6 μm, or about 3 to 4 μm. At least one of the adhesive layers used for dry lamination may be composed of the epoxy adhesive 13, and the other adhesive layers may be formed from the urethane adhesive 17 or the like.

[0046] The laminate 10, 20, 30 of the embodiment can be used for manufacturing a packaging body. At least one member of the packaging body may be formed from the laminate of the embodiment. Examples of the packaging body include packaging bags such as pouches and bags, tubes, containers, sleeve packaging, strip packaging, lid materials, and the like. Specific examples of the packaging bag include three-side seal bags, four-side seal bags, pillow bags, gusset bags, standing pouches, and the like. When the laminate is a flexible laminated film, a flexible packaging body can be formed. Since it is easy to refill and discard, it can be suitably used for a refill packaging body such as a refill pouch.

[0047] The packaging body may have a filling port, a pouring port, and the like. For example, the upper part of the packaging body is opened between the front and rear body members and can be used for filling or pouring the contents. After filling the contents, the space between the body members may be joined to seal the packaging body. The pouring port may be formed in a shape that protrudes thinly at the upper part or a corner of the packaging body. In order to facilitate opening of the packaging body, easy-opening means such as notches and half-cut grooves may be formed around the opening part.

[0048] The dimensions of the packaging body are not particularly limited. For example, in the case of a refill 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 ~5000 cm 3 or so. Examples of the state of the contents include fluids such as liquids, powders, and granules. The type of the contents is not particularly limited, and examples include detergents, drugs, cosmetics, pharmaceuticals, beverages, seasonings, inks, paints, fuels, and the like.

[0049] The packaging body may be formed only from the laminate 10, 20, 30 of the embodiment, or may be combined with accessory members such as labels, tags, straws, and outer boxes. From the viewpoint of recycling, it is preferable that the accessory members can be separated from the packaging body.

[0050] As described above, the present invention has been explained based on the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention. Examples of modifications include addition, replacement, omission, and other changes of components.

Example

[0051] Hereinafter, it will be described more specifically using examples. However, the present invention is not limited to these examples.

[0052] (Method for manufacturing a laminate) Laminates of Examples 1 to 3 and Comparative Examples 1 to 2 were manufactured according to the layer configurations shown in Table 1. In Table 1, "PE" represents a polyethylene-based resin layer, "PP" represents a polypropylene-based resin layer, "Epo" represents an epoxy-based adhesive using an epoxy-based main agent and an amide-based curing agent, "Ure" represents a urethane-based adhesive, and "Ink" represents a printed layer. "MDO-PE" is a uniaxially stretched PE film in the MD direction, "BOPE" is a biaxially stretched PE film, and "BOPP" is a biaxially stretched PP film. The numerical values in parentheses attached to the symbols of the resin layers are the thicknesses (μm).

[0053] In Examples 1 to 2 and Comparative Examples 1 to 2, a PE substrate with a thickness of 25 μm and a PE sealant with a thickness of 150 μm were laminated by a dry lamination method using an epoxy-based adhesive or a urethane-based adhesive to obtain a laminate. In Example 3, a PP substrate with a thickness of 18 μm and a PE sealant with a thickness of 100 μm were laminated by a dry lamination method using an epoxy-based adhesive to obtain a laminate.

[0054] In Example 1, an epoxy-based adhesive was laminated on the inner surface of the same MDO-PE substrate, and a printed layer was laminated on the outer surface. In Example 2, a printed layer and a urethane-based adhesive were superposed between the MDO-PE substrate and the BOPE substrate. In Example 3, a printed layer and a urethane-based adhesive were superposed between the BOPP substrates.

[0055] In Comparative Example 1, only a urethane-based adhesive was used at two layer interfaces. In Comparative Example 2, a printing layer and an epoxy-based adhesive were superposed between the MDO-PE substrate and the BOPE substrate.

[0056] (Oxygen barrier property of the laminate) The oxygen gas permeability (cc / m 2 ·day·atm) of the obtained laminate was measured under the conditions of a temperature of 30°C and a humidity of 70%RH.

[0057] (Interlayer peeling of the laminate) The laminate (laminated film) was folded twice, clamped in a state where four layers were overlapped, stored in a 40°C dry environment for one week, and the presence or absence of interlayer peeling was confirmed.

[0058]

Table 1

[0059] The laminate of Comparative Example 1 had a low oxygen barrier property. In the laminate of Comparative Example 2, interlayer peeling of the substrate occurred at the folded portion. The laminates of Examples 1 to 3 were excellent in oxygen barrier property, had high interlayer adhesion, and no interlayer peeling occurred even when the laminated film was folded.

Explanation of symbols

[0060] 10, 20, 30... laminates, 11... sealant layer, 12... substrate layer, 13... epoxy-based adhesive, 14... printing layer, 15... first substrate layer, 16... second substrate layer, 17... urethane-based adhesive.

Claims

1. A laminate having two or more polyolefin resin layers formed from a polyolefin resin, wherein at least one portion of the polyolefin resin layer is adhered using an epoxy-based adhesive, and a printing layer is laminated at a location not adjacent to the epoxy-based adhesive.

2. The laminate has, as the polyolefin resin layer, a sealant layer and a base material layer made of a polyethylene resin layer, and the interface between the sealant layer and the base material layer is adhered through the epoxy-based adhesive, and the printing layer is laminated on the outer surface of the base material layer. The laminate according to claim 1.

3. The laminate has, as the polyolefin resin layer, a sealant layer, a first base material layer, and a second base material layer made of a polyethylene resin layer. One of the interfaces between the sealant layer and the first base material layer and the interface between the first base material layer and the second base material layer is adhered through a urethane-based adhesive. The other one of the interfaces between the sealant layer and the first base material layer and the interface between the first base material layer and the second base material layer is adhered through the epoxy-based adhesive. The printing layer is laminated on the outer surface of the second base material layer. The laminate according to claim 1.

4. The laminate has, as the polyolefin resin layer, a sealant layer, a first base material layer, and a second base material layer made of a polyethylene resin layer. One of the interfaces between the sealant layer and the first base material layer and the interface between the first base material layer and the second base material layer is adhered through the epoxy-based adhesive. In the other one of the interfaces between the sealant layer and the first base material layer and the interface between the first base material layer and the second base material layer, the printing layer and the urethane-based adhesive layer are formed in any order. The laminate according to claim 1.

5. The epoxy-based adhesive is composed of an epoxy-based main agent and an amide-based curing agent. The laminate according to claim 1.

6. A package formed from the laminate according to any one of claims 1 to 5.

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