Gas barrier laminate and container

Abstract

The gas barrier laminate of the present disclosure has a laminate structure sequentially having a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer, the sealant layer containing at least one selected from a polyethylene-based resin and a polypropylene-based resin and a cyclic olefin-based resin, such that the tensile elastic modulus of the gas barrier layer is T A , the tensile elastic modulus of the sealant layer is T B , T A , and T B satisfy the following formula (1). -0.26 ≤ (T B -T A ) / T A ≤ 0.30 Formula (1).

Description

Technical Field

[0001] This disclosure relates to gas barrier laminates and containers. Background Technology

[0002] For a long time, paper containers for liquids, with paper as the main material, have been used in the field of packaging materials. Patent document 1 discloses a liquid paper container made by forming a box from packaging material, wherein the packaging material is formed from a paper substrate, a specific barrier layer, an adhesive resin layer of a specific thickness, and a heat-sealing resin layer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-171649 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, paper containers sometimes have puncture holes for sucking out the contained contents with a straw. These puncture holes are formed by creating through holes in the paper substrate.

[0008] However, when forming the straw puncture opening in the liquid paper container disclosed in Patent Document 1 above, there is room for improvement in terms of the punctureability of the straw.

[0009] Furthermore, aluminum foil has been considered for use in the gas barrier layer of paper containers to improve the puncture resistance of straws. However, this type of paper container cannot be inspected for foreign matter contamination using metal detectors, and the recycling process requires separating the aluminum foil from other materials, making it undesirable. Therefore, a packaging material that does not use aluminum foil and has excellent puncture resistance for straws is required.

[0010] Means for solving technical problems

[0011] This disclosure provides a gas barrier laminate with excellent straw puncture resistance, and a container obtained using the gas barrier laminate.

[0012] One aspect of this disclosure is a gas barrier laminate comprising a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer in sequence. The sealant layer comprises at least one of a polyethylene resin and a polypropylene resin, and a cyclic olefin resin, such that the tensile modulus of elasticity of the gas barrier layer is T. A The tensile elastic modulus of the sealant layer is T. B At that time, T A and T B It satisfies the following equation (1).

[0013] -0.26≤(TB -T A ) / T A ≤0.30 Equation (1)

[0014] One aspect of this disclosure is that the gas barrier laminate exhibits excellent straw puncture resistance. This effect is presumably achieved through the following mechanism: the straw puncture port formed in the gas barrier laminate has a hole penetrating the paper substrate, and sequentially comprises an adhesive resin layer, a gas barrier layer, and a sealant layer. Since the adhesive resin layer is the outer layer and the sealant layer is the inner layer, when the straw is inserted into the puncture port, the impact applied by the straw gradually attenuates as the straw penetrates the adhesive resin layer and the gas barrier layer, while simultaneously being transmitted to the sealant layer. Here, the sealant layer comprises at least one selected from polyethylene-based resins and polypropylene-based resins, and a cyclic olefin-based resin. Because the tensile elastic modulus of the gas barrier layer and the sealant layer satisfies the above formula (1), when the impact applied by the straw is transmitted to the sealant layer, the sealant layer easily ruptures along with the gas barrier layer. As a result, the gas barrier laminate exhibits excellent straw puncture resistance.

[0015] Another aspect of this disclosure describes a gas barrier laminate comprising a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer in sequence. The adhesive resin layer comprises at least one selected from polyethylene-based resins and polypropylene-based resins, and a cyclic olefin-based resin, such that the tensile modulus of elasticity of the gas barrier layer is T. A The tensile elastic modulus of the adhesive resin layer is T. C At that time, T A and T C It satisfies the following equation (2).

[0016] -0.26≤(T C -T A ) / T A ≤0.30 Equation (2)

[0017] Another aspect of this disclosure is the excellent straw puncture performance of the gas barrier laminate. This effect is presumably achieved through the following mechanism: When the straw is inserted into the straw puncture site, the straw penetrates the adhesive resin layer and reaches the gas barrier layer due to the impact exerted by the straw itself. Here, the adhesive resin layer comprises at least one selected from polyethylene-based resins and polypropylene-based resins, and a cyclic olefin-based resin. Since the tensile elastic modulus of the adhesive resin layer and the gas barrier layer satisfies the above formula (2), the straw easily reaches the gas barrier layer due to the impact exerted by the straw, and therefore the gas barrier layer easily ruptures along with the adhesive resin layer. Furthermore, since the gas barrier layer ruptures along with the adhesive resin layer, the impact from the straw also propagates to the sealant layer located outside the gas barrier layer, making the sealant layer also prone to rupture. As a result, the gas barrier laminate exhibits excellent straw puncture performance.

[0018] For the reasons of the container's excellent recyclability and superior straw puncture resistance, the gas barrier layer may include a polyolefin film as the film substrate, with the sealant layer in direct contact with the polyolefin film, and the lamination strength between the sealant layer and the polyolefin film being 1N / 15mm or higher.

[0019] The gas barrier layer can have an evaporated coating containing inorganic oxides for the sake of the container's excellent water resistance.

[0020] Another aspect of this disclosure relates to a container constructed from the aforementioned gas-barrier laminate. This container exhibits excellent straw puncture resistance.

[0021] Invention Effects

[0022] According to this disclosure, a gas barrier laminate capable of producing a container with excellent straw puncture resistance is provided, as well as a container obtained using the gas barrier laminate. Attached Figure Description

[0023] Figure 1 This is a schematic end view of a gas barrier laminate according to one embodiment of the present disclosure.

[0024] Figure 2 A perspective view of a container according to one embodiment of the present disclosure is shown schematically. Detailed Implementation

[0025] The following is a reference to the appendix. Figure 1 The embodiments of this disclosure are described below, but this disclosure is not limited to the following embodiments.

[0026] [Gas Barrier Laminate]

[0027] The following describes one embodiment of a gas barrier laminate (hereinafter also referred to as "laminate"). Figure 1 This is a schematic end view illustrating a stacked body according to one embodiment. (Example) Figure 1 As shown, the laminate 10 of this embodiment has a laminated structure comprising a paper substrate 1, an adhesive resin layer 2, a gas barrier layer 3, and a sealant layer 4 in sequence. A hole 1a is formed in the paper substrate 1, which serves as a puncture point for a straw. A protective layer 5 is disposed on the surface of the paper substrate 1 opposite to the surface that contacts the adhesive resin layer 2. The gas barrier layer 3 is formed of a vapor-deposited layer 3a and a film substrate 3b. The various components of the laminate 10 will be described below.

[0028] (Paper substrate)

[0029] As the paper substrate 1, for example, paper with properties such as shapeability, bending resistance, rigidity, stiffness, and strength can be used. Such paper can be, for example, highly sized sun-dried or unsun-dried paper, pure white tissue paper, kraft paper, cardboard, and processed paper.

[0030] For the sake of superior gas barrier properties of the resulting container, the unit area mass of the paper substrate 1 is preferably 80–600 g / m³. 2 More preferably, 200–450 g / m 2 .

[0031] The paper substrate 1 can be used to arbitrarily form desired printed patterns such as text, graphics, designs, and symbols using conventional printing methods.

[0032] (Adhesive resin layer)

[0033] The adhesive resin layer 2 comprises at least one selected from polyethylene resins and polypropylene resins and cyclic olefin resins.

[0034] Examples of polyethylene-based resins include low-density polyethylene, high-density polyethylene, copolymers of polyethylene and polyvinyl acetate, anhydride-modified polyethylene represented by terpolymers such as ethylene-ethyl acrylate-maleic anhydride, and epoxy-modified polyethylene such as ethylene-glycidyl methacrylate copolymers. Low-density polyethylene is preferred for improved puncture resistance. Examples of low-density polyethylene include linear low-density polyethylene and branched low-density polyethylene, with branched low-density polyethylene being preferred. Branched low-density polyethylene is preferably obtained by high-pressure free radical polymerization, and more preferably by homopolymerization of ethylene using high-pressure free radical polymerization. This type of low-density polyethylene has good puncture resistance due to its low mechanical strength and greater brittleness compared to other polyolefins. One type of polyethylene-based resin can be used alone or in combination of two or more types.

[0035] The preferred density of low-density polyethylene is 0.900 g / cm³. 3 ~0.935g / cm 3 More preferably 0.915 g / cm³ 3 ~0.930g / cm 3 If the density is within the above range, the film-forming properties and extrusion adaptability of the adhesive resin layer 2 are improved because low-density polyethylene has moderate rigidity.

[0036] The melting point of polyethylene-based resins is preferably lower than the glass transition temperature (Tg) of cyclic olefin-based resins, preferably 60–130°C, more preferably 70–120°C. If the melting point is within this range, co-extrusion processability and compatibility are improved.

[0037] Examples of polypropylene-based resins include propylene homopolymers, anhydride-modified polypropylene (represented by terpolymers such as propylene-α-olefin random copolymers and propylene-ethyl acrylate-maleic anhydride copolymers), and epoxy-modified polypropylene (represented by propylene-glycidyl methacrylate copolymers). Examples of propylene-α-olefin random copolymers include propylene-ethylene copolymers, propylene-butene-1 copolymers, and propylene-ethylene-butene-1 copolymers. The polypropylene-based resins can be synthesized using metallocene catalysts. The polypropylene-based resins are preferably propylene-α-olefin random copolymers, and more preferably propylene-α-olefin random copolymers polymerized using metallocene catalysts. By using these polypropylene-based resins, the heat resistance of the adhesive resin layer 2 is improved, and the softening temperature can be increased. Therefore, the laminate 10 is preferably used for sterilization applications involving steam heating or high-pressure heating, such as boiling or hot filling at temperatures below 100°C, or high-temperature sterilization at temperatures above 100°C. One type of polypropylene-based resin can be used alone or in combination of two or more types.

[0038] The melting point of polypropylene resin is preferably 110–165°C, more preferably 115–160°C. The melting point of polypropylene resin can be appropriately changed according to the glass transition temperature (Tg) of cyclic olefin resin.

[0039] Cyclic olefin resins are not particularly limited, and examples include ring-opening polymers (COP), norbornene polymers (COC), vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred from the viewpoint of compatibility with polyethylene resins.

[0040] Commercially available ring-opening polymers of norbornene monomers include, for example, ZEONOR (trade name) manufactured by ZEON Corporation of Japan. Commercially available norbornene polymers include APEL (trade name) manufactured by Mitsui Chemicals Co., Ltd., and TOPAS (trade name) manufactured by Polyplastics Co., Ltd.

[0041] The density of the cyclic olefin resin is preferably 0.99 g / cm³. 3 ~1.05g / cm 3 More preferably 1.00 g / cm³ 3 ~1.03g / cm 3 If the density is within the above range, the film-forming properties and extrusion adaptability of the adhesive resin layer 2 are improved.

[0042] The glass transition temperature (Tg) of the cyclic olefin resin is preferably 60°C to 180°C, more preferably 70°C to 150°C. When Tg is within the above range, the film-forming properties and extrusion adaptability of the adhesive resin layer 2 are improved.

[0043] The mass ratio of the total mass of polyethylene-based resin and polypropylene-based resin to the mass of cyclic olefin-based resin in the adhesive resin layer 2 (total mass of polyethylene-based resin and polypropylene-based resin / mass of cyclic olefin-based resin) is preferably 70 / 30 or more, more preferably 80 / 20 or more, and preferably 95 / 5 or less, more preferably 90 / 10 or less. With a mass ratio within this range, puncture resistance is further improved.

[0044] The total mass of polyethylene resin, polypropylene resin and cyclic olefin resin in adhesive resin layer 2 is based on the total mass of adhesive resin layer 2, and can be 80% or more, 90% or more, or 95% or more.

[0045] The thickness of the adhesive resin layer 2 is preferably 1 to 40 μm, more preferably 10 to 40 μm, and even more preferably 15 to 25 μm. The adhesive resin layer 2 may or may not be subjected to uniaxial tension.

[0046] (Sealant layer)

[0047] The sealant layer 4 comprises at least one selected from polyethylene resins and polypropylene resins, and a cyclic olefin resin. The same materials as those used in the adhesive resin layer 2 can be used as the polyethylene resin, polypropylene resin, and cyclic olefin resin. The mass ratio and total mass of the polyethylene resin, polypropylene resin, and cyclic olefin resin in the sealant layer 4 are the same as those in the adhesive resin layer 2.

[0048] The thickness of the sealant layer 4 is not particularly limited, but it is preferably 20 μm to 50 μm when considering its adaptability as a packaging material and its processability when layering other films or forming a vapor-deposited layer.

[0049] The sealant layer 4 may also contain antifogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, anti-blocking agents, release agents, ultraviolet absorbers, and colorants, as needed and without compromising the purpose of the present invention.

[0050] The lamination method of the sealant layer 4 can be, for example, extrusion lamination, T-die extrusion molding, co-extrusion lamination, blow molding, and co-extrusion blow molding.

[0051] (Vapor-deposited layer)

[0052] Evaporated layer 3a is coated with silicon oxide (SiO2). xThe layer 3a is formed by depositing a vapor-deposited layer. As a result, the water resistance of the laminate 10 becomes excellent. The thickness of the vapor-deposited layer 3a can be appropriately set according to the application, preferably 1–300 nm, more preferably 10–300 nm, and even more preferably 30–100 nm. When the thickness of the vapor-deposited layer 3a is 1 nm or more, the continuity of the vapor-deposited layer 3a is easily ensured; when it is 300 nm or less, the occurrence of curling or cracking can be effectively suppressed, and sufficient gas barrier performance and flexibility can be easily achieved.

[0053] The vapor-deposited layer 3a can also be coated with silicon oxide (SiO2). x A layer of inorganic oxides or metals other than aluminum oxide (AlO2). As a vapor-deposited layer 3a, it can be, for example, obtained by vapor deposition of aluminum, or it can be a layer containing aluminum oxide (AlO2). x )

[0054] From the viewpoint of oxygen barrier properties or film uniformity, vacuum deposition is preferred for the vapor-deposited layer 3a. Known methods include vacuum deposition, sputtering, and chemical vapor deposition (CVD), but vacuum deposition is preferred for its high speed and productivity. Furthermore, vacuum deposition methods, particularly those using electron beam heating, are effective because the deposition rate can be easily controlled by adjusting the irradiation area or electron beam current, or because the temperature of the vapor-deposited material can be rapidly increased and decreased.

[0055] (Membrane substrate)

[0056] Examples of materials that can be used as the membrane substrate 3b include polyolefin films, polyethylene terephthalate films, and nylon films. The membrane substrate 3b is preferably a polyolefin film. By using a polyolefin film, it can be recycled as an olefin-based plastic material along with the adhesive resin layer 2 and the sealant layer 4. Examples of polyolefin films include polypropylene films and polyethylene films. The membrane substrate 3b can be a uniaxially stretched film or a biaxially stretched film.

[0057] When the membrane substrate 3b is a polyolefin membrane, the lamination strength between the membrane substrate 3b and the sealant layer 4 is preferably 1 N / 15 mm or more, more preferably 1.5 N / 15 mm or more, and even more preferably 2 N / 15 mm or more, for the sake of better puncture resistance. The lamination strength is measured according to JIS Z-1707.

[0058] The wettability of the membrane substrate 3b in contact with the polyolefin membrane, achieving this lamination strength, is 34 dynes or higher when the lamination strength is 1 N / 15 mm or higher, 36 dynes or higher when it is 1.5 N / 15 mm or higher, and 38 dynes or higher when it is 2 N / 15 mm or higher. The wettability is measured according to JIS K6768:1999. The wettability of the membrane substrate 3b surface can be adjusted, for example, by subjecting the membrane substrate 3b to corona treatment.

[0059] From the viewpoint of ease of processing such as lamination, the thickness of the film substrate 3b is preferably 15 to 30 μm, more preferably 18 to 20 μm.

[0060] (protective layer)

[0061] The material of the protective layer 5 can be, for example, polyethylene resin. Using polyethylene resin for the protective layer 5 results in a container with excellent recyclability. Medium-density polyethylene and high-density polyethylene are preferred for their high physical strength and superior gas barrier properties of the resulting container. The thickness of the protective layer 5 is preferably 10–30 μm, more preferably 15–20 μm, for the same reason as the superior gas barrier properties of the resulting container.

[0062] The laminate 10 makes the tensile elastic modulus of the gas barrier layer 3 T. A The tensile elastic modulus of sealant layer 4 is T. B At that time, T A And T B It satisfies the following equation (1).

[0063] -0.26≤(T B -T A ) / T A ≤0.30 Equation (1)

[0064] (T B -TA) / T A For the sake of superior puncture resistance, a value of -0.20 or higher is preferred, and more preferably -0.10 or higher. (T) B -T A ) / T A From the same point of view, it is preferred to be 0.25 or less, more preferably 0.10 or less, and even more preferably 0.05 or less.

[0065] The laminate 10 makes the tensile elastic modulus of the gas barrier layer 3 T. A The tensile elastic modulus of the adhesive resin layer 2 is T. C At that time, T A And T C It satisfies the following equation (2).

[0066] -0.26≤(T C -T A ) / T A ≤0.30 Equation (2)

[0067] (T C -T A ) / T A For the sake of superior puncture resistance, a value of -0.20 or higher is preferred, and more preferably -0.10 or higher. (T)C -T A ) / T A From the same point of view, it is preferred to be 0.25 or less, more preferably 0.10 or less, and even more preferably 0.05 or less.

[0068] The tensile elastic modulus T of the gas barrier layer 3 A It can be above 800MPa or below 1300MPa.

[0069] T A T B And T C Determined according to ISO 527.

[0070] The laminate 10 is obtained by stacking the individual layers. Examples of methods for stacking the layers include extrusion lamination, T-die extrusion molding, co-extrusion lamination, blow molding, and co-extrusion blow molding. The main surfaces of each layer may also be subjected to treatments such as corona treatment, plasma treatment, and ozone treatment before stacking.

[0071] The aforementioned laminate 10 exhibits excellent straw puncture resistance. This effect is presumably due to the following mechanism: when the straw is inserted into the puncture site, the impact exerted by the straw gradually diminishes as it penetrates the adhesive resin layer and the gas barrier layer, while simultaneously being transmitted to the sealant layer. Here, the adhesive resin layer 2 and the sealant layer 4 comprise at least one selected from polyethylene-based resins and polypropylene-based resins, and a cyclic olefin-based resin. A T B And T C The above equations (1) and (2) are satisfied. Therefore, the impact applied by the self-drip tube is easily transmitted to the sealant layer 4, and the adhesive resin layer 2, the gas barrier layer 3, and the sealant layer 4 are easily broken together. As a result, the straw puncture resistance of the laminate 10 is excellent.

[0072] The straw of the laminate 10 has excellent puncture resistance. Therefore, even if the straw is not made of commonly used plastic, but of a material that is difficult to apply force to, it can still be inserted well.

[0073] The embodiments of this disclosure have been described in detail above, but this disclosure is not limited to the above embodiments. For example, in the laminate 10, the lamination order of the film substrate 3b and the vapor-deposited layer 3a can be interchanged. In this case, the lamination strength between the film substrate 3b and the adhesive resin layer 2 can be the same as the lamination strength between the film substrate 3b and the sealant layer 4. In the laminate 10, the vapor-deposited layer 3a may also be omitted.

[0074] In the laminate 10, only the adhesive resin layer 2 may contain a resin selected from polyethylene resins and polypropylene resins, and a cyclic olefin resin, in the adhesive resin layer 2 and the sealant layer 4. In this case, the sealant layer 4 may not satisfy the above formula (1).

[0075] In the laminate 10, only the sealant layer 4 may contain at least one of polyethylene resin and polypropylene resin and a cyclic olefin resin, in the adhesive resin layer 2 and the sealant layer 4. In this case, the adhesive resin layer 2 may not satisfy the above formula (2).

[0076] [container]

[0077] The following describes the container (paper container) of this embodiment. Figure 2 The container 50 shown is composed of a stack of layers 10.

[0078] Container 50 can be used to fill and package various food and beverage products, adhesives and other chemicals, cosmetics, pharmaceuticals, and other general merchandise. Container 50 is particularly preferred for use as a packaging container for filling and packaging liquid condiments such as wine, dairy products such as milk, fruit juices, mineral water, soy sauce and other sauces, as well as liquid food and beverages such as curry, stews, and soups, due to its excellent puncture resistance and gas barrier properties.

[0079] Container 50 is a brick-shaped container. Container 50 has a rectangular container body 52 with an upper part 52a, a side part 52b, and a bottom part 52c having a straw puncture port 51. In the laminate 10, the straw puncture port 51 is a portion in the paper substrate 1 where a hole 1a is formed.

[0080] The container of this embodiment has been described in detail above, but the container disclosed herein is not limited to the above embodiment. For example, the shape of the container is not limited to the shape of container 50; it may also be a roof-shaped or triangular pyramidal shape. In addition, the shape of the main body of the container may also be cylindrical.

[0081] Example

[0082] The present disclosure is described in more detail below with reference to embodiments and comparative examples, but the present disclosure is not limited to the following embodiments.

[0083] The following materials are prepared as cyclic olefin resins and polyethylene resins.

[0084] • Cyclic olefin resin A: TOPAS 5013F-04 (trade name, norbornene polymer, tensile modulus: 2600MPa, manufactured by POLYPLASTICS Co., Ltd.)

[0085] • Cyclic olefin resin B: ZEONOR 1020R (trade name, ring-opening polymer of norbornene monomers, cyclic olefin polymer, tensile modulus: 2100MPa, manufactured by ZEON Corporation, Japan)

[0086] • Cyclic olefin resin C: TOPAS 6015S-04 (trade name, norbornene polymer, tensile modulus of elasticity of 3000MPa, manufactured by POLYPLASTICS Co., Ltd.)

[0087] • Cyclic olefin resin D: TOPAS 9506F-500 (trade name, norbornene polymer, tensile modulus of elasticity of 1800MPa, manufactured by POLYPLASTICS Co., Ltd.)

[0088] • Polyethylene resin A: LW14A (trade name, low-density polyethylene, tensile modulus: 520MPa, manufactured by Tosoh Corporation)

[0089] • Polyethylene resin B: 6530 (trade name, high-density polyethylene, tensile modulus: 1020MPa, manufactured by Tosoh Corporation)

[0090] The tensile modulus of elasticity of cyclic olefin resins and polyethylene resins are values ​​determined according to ISO 527.

[0091] [Manufacturing of laminates]

[0092] (Example 1)

[0093] The laminate of this example is obtained through the following process. Specifically, a resin mixture is obtained by dry blending polyethylene resin A and cyclic olefin resin A, which form the sealant layer and the adhesive resin layer. The mass ratio of the polyethylene resin to the cyclic olefin resin (mass of polyethylene resin / mass of cyclic olefin resin) is 80 / 20.

[0094] Next, a gas barrier film with a silica-based vapor-deposited layer (silica vapor-deposited layer, thickness: 50 nm) is prepared on one surface of a membrane substrate (material: polypropylene resin, thickness: 18 μm). The side of the membrane substrate opposite to the side with the vapor-deposited layer is subjected to corona treatment to achieve a surface wettability of 40 dynes. On the corona-treated surface of the membrane substrate, a resin mixture is extruded and laminated to form a sealant layer (thickness: 30 μm) to obtain the inner layer material. The surface wettability of the membrane substrate is measured using a wettability tension test solution (manufactured by Kanto Chemical Co., Ltd.) according to JIS K 6768: 1999.

[0095] On the other hand, the paper substrate with through holes serving as straw puncture openings (mass per unit area: 260g / m²) 2 A protective layer (material: polyethylene resin, thickness: 20 μm) is formed on one surface of the paper substrate to obtain an outer layer material containing the paper substrate. The inner layer material and the outer layer material are then bonded together by extrusion lamination using a resin mixture (adhesive resin layer) to obtain a laminate (packaging material). The thickness of the adhesive resin layer is 15 μm.

[0096] (Example 2)

[0097] Except that cyclic olefin resin B is used instead of cyclic olefin resin A, a laminate is obtained in the same manner as in Example 1.

[0098] (Example 3)

[0099] Except that cyclic olefin resin C is used instead of cyclic olefin resin A, a laminate is obtained in the same manner as in Example 1.

[0100] (Example 4)

[0101] Except that cyclic olefin resin C is used instead of cyclic olefin resin A, and the mass ratio of polyethylene resin to cyclic olefin resin is 85 / 15, a laminate is obtained in the same manner as in Example 1.

[0102] (Example 5)

[0103] The laminate of this example was obtained through the following steps. Specifically, a resin mixture was obtained in the same manner as in Example 1, except that polyethylene resin B was used instead of polyethylene resin A. Next, a gas barrier membrane was prepared in the same manner as in Example 1, and corona treatment was performed. The resin mixture and polyethylene resin A were co-extruded and laminated on the corona-treated surface of the membrane substrate to form a sealant layer (thickness: 30 μm), thus obtaining the inner layer material. Using co-extrusion lamination, a layer formed of the resin mixture was formed on the corona-treated surface of the membrane substrate, and a layer formed of polyethylene resin A was formed on top of the layer formed of the resin mixture. Using the obtained inner layer material, a laminate was obtained in the same manner as in Example 1.

[0104] (Example 6)

[0105] Except that the mass ratio of polyethylene resin to cyclic olefin resin is 95 / 5, a laminate is obtained in the same manner as in Example 5.

[0106] (Example 7)

[0107] Except that polyethylene resin A was used instead of resin mixture as the resin for bonding inner and outer layer materials, a laminate was obtained in the same manner as in Example 1.

[0108] (Comparative Example 1)

[0109] Except that the mass ratio of polyethylene resin to cyclic olefin resin is 97 / 3, a laminate was obtained in the same manner as in Example 1.

[0110] (Comparative Example 2)

[0111] Except that cyclic olefin resin D is used instead of cyclic olefin resin A, a laminate is obtained in the same manner as in Example 1.

[0112] (Comparative Example 3)

[0113] Except that the mass ratio of polyethylene resin to cyclic olefin resin is 50 / 50, a laminate is obtained in the same manner as in Example 1.

[0114] [Determination of tensile modulus of elasticity]

[0115] The tensile modulus T of the gas barrier film, sealant layer, and adhesive resin layer of the laminates in the embodiments and comparative examples was determined according to ISO 527-3. A T B And T C The results are shown in Table 1. Additionally, calculate (T) B -T A ) / T A and (T) C -T A ) / T A The results are shown in Table 1.

[0116] [Determination of lamination strength]

[0117] For the laminates obtained in each embodiment and comparative example, the lamination strength between the sealant layer and the gas barrier film was measured. The measurement was performed according to JIS Z-1707. Specifically, the laminate was cut into strips 15 mm wide. Using a TENSILON tensile testing machine (product name "TENSILON RTC-1250", manufactured by Orientec), the sealant layer of the laminate cut into strips was peeled from the gas barrier film at a peeling speed of 300 mm / min, with the sealant layer and gas barrier film on opposite sides (i.e., a T-shaped peel angle). The strength required for peeling (unit: N / 15 mm) was measured as the lamination strength. The results are shown in Table 1.

[0118] [Penetrating]

[0119] The puncture resistance of the laminates obtained in each embodiment and comparative example was evaluated as follows: Evaluation 1 and Evaluation 2. The results are shown in Table 1.

[0120] <Evaluation 1>

[0121] The puncture strength of the laminate was determined. Specifically, a tensile-compression testing machine (manufactured by Shimadzu Corporation) was used to insert a needle into the protective layer side of the pipette puncture site of the laminate. A hemispherical needle with a hemispherical tip (diameter: 0.5 mm) was used. The needle insertion speed was 50 mm / min. The measured value of the puncture strength was the peak value measured during needle insertion.

[0122] <Rating 2>

[0123] A straw (tip angle: 45°, material: plastic) is installed at the tip of the push-pull gauge (manufactured by Imada Co., Ltd., trade name: "DPX-5T"). The straw is inserted through the protective layer side of the straw puncture port on the laminate. Punctureability is evaluated according to the following criteria.

[0124] 4: There is no stretching or jamming, and no resistance is felt.

[0125] 3: There is no stretching or jamming, and almost no resistance is felt.

[0126] 2: Although it did not stretch or get stuck, I felt a slight resistance.

[0127] 1: There is a stretching or jamming sensation, and resistance is felt.

[0128]

[0129] The laminates obtained in each embodiment exhibited good puncture resistance. On the other hand, the laminates obtained in Comparative Examples 1 and 2 stretched upon insertion into the straw. The laminate obtained in Comparative Example 3 became stuck upon insertion into the straw.

[0130] The purpose of this disclosure is as follows [1] to [6].

[0131] [1] A gas barrier laminate having a laminated structure comprising, in sequence, a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer.

[0132] The aforementioned sealant layer comprises at least one selected from polyethylene resins and polypropylene resins, and a cyclic olefin resin.

[0133] Let the tensile elastic modulus of the above-mentioned gas barrier layer be T. A The tensile elastic modulus of the above-mentioned sealant layer is T. B At that time, T A And T B It satisfies the following equation (1).

[0134] -0.26≤(T B -T A) / T A ≤0.30 Equation (1)

[0135] [2] A gas barrier laminate having a laminated structure comprising, in sequence, a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer.

[0136] The aforementioned adhesive resin layer comprises at least one selected from polyethylene resins and polypropylene resins, and a cyclic olefin resin.

[0137] Let the tensile elastic modulus of the above-mentioned gas barrier layer be T. A The tensile elastic modulus of the above-mentioned adhesive resin layer is T. C At that time, T A And T C It satisfies the following equation (2).

[0138] -0.26≤(T C -T A ) / T A ≤0.30 Equation (2)

[0139] [3] According to the gas barrier laminate described in [1] or [2], wherein,

[0140] The aforementioned gas barrier layer, as a membrane substrate, comprises a polyolefin membrane.

[0141] The sealant layer is in direct contact with the polyolefin film.

[0142] The lamination strength between the above-mentioned sealant layer and the above-mentioned polyolefin film is 1N / 15mm or more.

[0143] [4] According to the gas barrier layer stack of [3], wherein the gas barrier layer has a vapor-deposited layer containing inorganic oxides.

[0144] [5] A container comprising the gas barrier laminate described in [1] or [2].

[0145] [6] The container according to [5] has a straw puncture port with a hole formed through the paper substrate.

[0146] Symbol Explanation

[0147] 1. Paper substrate, 2. Adhesive resin layer, 3. Gas barrier layer, 4. Sealant layer, 5. Protective layer, 10. Laminated body, 50. Container.

Claims

1. A gas barrier laminate having a laminated structure comprising, in sequence, a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer. The paper substrate has a hole that penetrates the paper substrate, serving as a puncture port for a straw. The gas barrier layer comprises a polypropylene membrane as the membrane substrate and has a vapor-deposited layer containing silicon oxide. The sealant layer comprises polyethylene resin and cyclic olefin resin. The tensile elastic modulus of the gas barrier layer is T. A The tensile elastic modulus of the sealant layer is T. B At that time, T A And T B It satisfies the following equation (1). -0.26≤(T B -T A ) / T A ≤0.30 Equation (1).

2. A gas barrier laminate having a laminated structure comprising, in sequence, a paper substrate, an adhesive resin layer, a gas barrier layer, and a sealant layer. The paper substrate has a hole that penetrates the paper substrate, serving as a puncture port for a straw. The adhesive resin layer comprises at least one selected from polyethylene resins and polypropylene resins, and cyclic olefin resins. The gas barrier layer comprises a polypropylene membrane as the membrane substrate and has a vapor-deposited layer containing silicon oxide. The sealant layer comprises polyethylene resin and cyclic olefin resin. The tensile elastic modulus of the gas barrier layer is T. A The tensile elastic modulus of the sealant layer is T. B The tensile elastic modulus of the adhesive resin layer is T. C At that time, T A And T B Satisfying the following equation (1), T A And T C It satisfies the following equation (2). -0.26≤(T B -T A ) / T A ≤0.30 Equation (1) -0.26≤(T C -T A ) / T A ≤0.30 Equation (2).

3. The gas barrier laminate according to claim 1 or 2, wherein, The sealant layer is in direct contact with the polyolefin film. The lamination strength between the sealant layer and the polyolefin film is greater than 1 N / 15 mm.

4. A container comprising a gas barrier laminate according to any one of claims 1 to 3.

5. The container according to claim 4, comprising a straw puncture port having a hole formed through the paper substrate.

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