Laminate and plastic container

Abstract

To provide a laminate having excellent interlayer bonding strength.SOLUTION: A laminate according to the present invention comprises a cyclic olefinic resin layer, an adhesion layer and a polypropylene resin layer which are laminated in this order. The polypropylene resin layer comprises a polypropylene resin and a linear low-density polyethylene. The interlayer bonding strength between the cyclic olefinic resin layer and the adhesion layer is 25 N / 15 mm or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate and a plastic container. [Background technology]

[0002] In various fields such as the medical field, food field, and cosmetics field, film-like laminates in which multiple resin layers are laminated are used as container materials for plastic containers filled with medicines, food products, cosmetics, etc. Plastic containers formed using laminates are easy to handle and dispose of, and are therefore used, for example, as drug solution bags for storing drug solutions such as infusions.

[0003] As a laminate to be formed into a plastic container such as a drug solution bag, for example, a multilayer film has been disclosed which includes a sealing layer made of polypropylene and an outermost layer containing polypropylene, and between these, a cyclic polyolefin layer made of a cyclic polyolefin polymer or a cyclic polyolefin copolymer and a resin composition layer made of a blend of a propylene-based polymer and a styrene-based elastomer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2009 / 066752 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the multilayer film of Patent Document 1, the cyclic olefin-based resin, such as the cyclic polyolefin polymer contained in the cyclic polyolefin layer, is difficult to obtain adhesive strength with the resin composition layer, so the interlayer adhesive strength between the cyclic polyolefin layer and the outermost layer is low, and peeling between these layers is likely to occur, which is a problem.

[0006] An object of one aspect of the present invention is to provide a laminate that can have excellent interlayer adhesive strength. [Means for solving the problem]

[0007] One aspect of the present invention provides a laminate comprising a cyclic olefin-based resin layer, an adhesive layer, and a polypropylene-based resin layer laminated in this order, wherein the polypropylene-based resin layer contains a polypropylene-based resin and a linear low-density polyethylene, and the interlayer adhesive strength between the cyclic olefin-based resin layer and the adhesive layer is 25 N / 15 mm or more. [Effects of the Invention]

[0008] One aspect of the present invention can provide a laminate that can have excellent interlayer adhesive strength. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing the configuration of a laminate according to an embodiment of the present invention. [Figure 2] FIG. 1 is a side view showing an example of a plastic container. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail. To facilitate understanding of the description, the scale of each component in the drawings may differ from the actual scale. In this specification, unless otherwise specified, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0011] <Laminate> A laminate according to an embodiment of the present invention will be described. Fig. 1 is a schematic cross-sectional view showing the configuration of the laminate according to this embodiment. As shown in Fig. 1, the laminate 1 according to this embodiment comprises a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30 laminated in this order, and the interlayer adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20 is 25 N / 15 mm or more. The laminate 1 is formed in the shape of a sheet (film).

[0012] The interlayer adhesive strength refers to the adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 via the adhesive layer 20. The method for measuring the interlayer adhesive strength is not particularly limited as long as it can measure the adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30. For example, the laminate 1 is cut to a predetermined size, and a portion of the interlayer is separated from one end of the cut laminate 1. Then, using a tensile tester or the like, a tensile load is applied to the cyclic olefin resin layer 10 and the polypropylene resin layer 30 of the laminate 1 cut to a predetermined size at a predetermined tensile speed (e.g., 5 mm / min) to cause delamination over a predetermined length (e.g., 30 mm). The load (unit: N / 15 mm) required for this delamination may be measured as the interlayer adhesive strength. The interlayer adhesive strength may also be the average load measured using multiple laminates.

[0013] The laminate 1 may have two or more layers of each of the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30, or may have layers other than the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30.

[0014] (Cyclic olefin resin layer) The cyclic olefin resin layer 10 mainly contains a cyclic olefin resin. The cyclic olefin resin contained in the cyclic olefin resin layer 10 is a polymer of one or more olefin monomers or a polymer in which the double bonds of the olefin monomers are hydrogenated, and at least one of the olefin monomers is a cyclic olefin monomer having a cyclic hydrocarbon skeleton. Examples of the cyclic olefin monomer include norbornene compounds. In the following description, the term "cyclic olefin resin" simply refers to the cyclic olefin resin contained in the cyclic olefin resin layer 10.

[0015] Cyclic olefin resins include polymers obtained by hydrogenating the remaining double bonds after ring-opening metathesis polymerization of norbornene compounds, addition polymers made of two or more cyclic olefin monomers, and addition polymers obtained by copolymerizing a cyclic olefin monomer and a non-cyclic olefin monomer. However, homopolymers made of only one cyclic olefin monomer are not preferred. Methods for producing cyclic olefin resins include hydrogenating a ring-opening metathesis polymer of a norbornene compound, copolymerizing two or more cyclic olefin monomers, and copolymerizing a cyclic olefin monomer with an α-olefin.

[0016] Among cyclic olefin resins, the basic structure of a polymer obtained by hydrogenating a ring-opening metathesis polymer of a norbornene compound can be represented by the following formula (I), for example. That is, the polymer of the following formula (I) is described as a polymer in which a cyclic skeleton and an ethylene skeleton are alternately arranged. The cyclic skeleton of the following formula (1) is a 1,3-cyclopentylene skeleton. However, the ring-opening metathesis polymer of a norbornene compound itself does not need to be a copolymer.

[0017] [ka]

[0018] In formula (I), n is an integer of 1 or more, and R 1 and R 2 represents a hydrogen atom or an alkyl group. 1and R 2 may be the same or different. 1 and R 2 may be bonded to each other to form a ring.

[0019] The structure shown in the above formula (I) is a 1,3-cyclopentylene skeleton having n substituents R 1 and R 2 are the same and the ring-opening metathesis polymer of the norbornene compound is a homopolymer.

[0020] The structure shown in the above formula (I) may be a polymer obtained by hydrogenating a ring-opening metathesis polymer of two or more norbornene compounds. Examples of such polymers include those shown in the following formula (II).

[0021] [ka]

[0022] In formula (II), m and n are integers of 1 or more, and R 1 and R 2 represents a hydrogen atom or an alkyl group. m and n may be the same or different. R 1 and R 2 may be the same or different. 1 and R 2 may be bonded to each other to form a ring.

[0023] Specific examples of polymers obtained by hydrogenating ring-opening metathesis polymers of norbornene compounds include the ZEONEX (registered trademark) series and the ZEONOR (registered trademark) series manufactured by Zeon Corporation.

[0024] Furthermore, an addition polymer obtained by copolymerizing a cyclic olefin monomer and an acyclic olefin monomer can be represented by the following formula (III). The addition polymer of the following formula (III) is described as a polymer in which a cyclic skeleton and an ethylene skeleton are randomly arranged. The cyclic skeleton of the following formula (I1I) is a 2,3-norbornanylene skeleton.

[0025] [ka]

[0026] In formula (III), m and n are integers of 1 or more, and R 1 , R 2 and R 3 represents a hydrogen atom or an alkyl group. m and n may be the same or different. R 1 , R 2 and R 3 may be the same or different. 1 and R 2 may be bonded to each other to form a ring.

[0027] R 1 , R 2 and R 3 An example of a polymer in which R are both hydrogen atoms is TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd. 1 and R 2 is an alkyl group, and R 3 An example of a polymer in which is a hydrogen atom is APEL (registered trademark) manufactured by Mitsui Chemicals, Inc.

[0028] These cyclic olefin resins have excellent water vapor barrier properties and are easily available. As described above, the laminate 1 according to this embodiment can use these cyclic olefin resins as the main component of the cyclic olefin resin layer 10. The cyclic olefin resin layer 10 may contain one type of cyclic olefin resin, or may contain two or more types of cyclic olefin resins.

[0029] Here, the two or more cyclic olefin resins may be two or more cyclic olefin resins corresponding to any one of the above formulas (I) to (III), or may be one or more cyclic olefin resins for each of two or more formulas (I) to (III). The two or more cyclic olefin resins may further include a cyclic olefin resin that does not correspond to the above formulas (I) to (III).

[0030] The cyclic olefin resin layer 10 may be the innermost layer in the laminate 1 and may be used as a sealant layer.

[0031] Commercially available cyclic olefin resins partially overlap with those listed above, but examples thereof include ZEONEX (registered trademark) (manufactured by Zeon Corporation, a hydrogenated polymer of a ring-opening metathesis polymer of a norbornene-based monomer), ZEONOR (registered trademark) (manufactured by Zeon Corporation, a copolymer based on the ring-opening polymerization of dicyclopentadiene and tetracyclopentadodecene), TOPAS (registered trademark) (manufactured by Polyplastics Co., Ltd., a copolymer of norbornene and ethylene), APEL (registered trademark) (manufactured by Mitsui Chemicals, Inc., a copolymer of ethylene and tetracyclododecene), and ARTON (registered trademark) (manufactured by JSR Corporation, a cyclic olefin resin containing a polar group, made from dicyclopentadiene and a methacrylic acid ester as raw materials).

[0032] The cyclic olefin resin layer 10 may contain other resin components in addition to the cyclic olefin resin. Examples of other resin components include one or more of polyolefin resins such as polyethylene, polypropylene, polybutene, ethylene-α-olefin copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer; urethane resins; rubber resins; polyester resins; polyester-urethane resins; acrylic resins; amide resins; styrene resins; and silane resins. Among these, examples of styrene resins include polystyrene, styrene-acrylonitrile copolymer (SAN), and styrene elastomers. It is particularly preferred that the cyclic olefin resin layer 10 contain one or more components, such as styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene copolymer, styrene-isoprene-styrene block copolymer (SIS), hydrogenated products thereof (e.g., SEBS, SEPS), and styrene-butadiene random copolymer, in an amount ranging from 0.05% by mass to 20% by mass.

[0033] By containing other resin components, the cyclic olefin resin layer 10 can improve the desired performance of the plastic container, such as the impact resistance of the plastic container at low temperatures, maintaining transparency immediately after high-pressure steam sterilization, and improving flexibility.

[0034] The cyclic olefin resin layer 10 preferably contains only a cyclic olefin resin as the resin component (it may contain non-resin additives), and may contain 100% by mass of a cyclic olefin resin (it does not contain any other additives). When it contains the other resin components, it is preferable that the cyclic olefin resin layer is primarily composed of a cyclic olefin resin. That is, the cyclic olefin resin layer 10 preferably contains one type of cyclic olefin resin or two or more types of cyclic olefin resins in total at 50% by mass or more, and particularly preferably at 70% by mass or more. If the composition ratio of the cyclic olefin resin is low, trace components or pharmaceutical ingredients with high affinity for plastics may be adsorbed, which may result in insufficient storage stability of the pharmaceutical ingredients contained therein.

[0035] (adhesive layer) The adhesive layer 20 is an intermediate layer for bonding the cyclic olefin resin layer 10 and the polypropylene resin layer 30. The adhesive layer 20 contains linear low-density polyethylene (LLDPE) and may contain a styrene-based elastomer. The adhesive layer 20 may be substantially composed of linear low-density polyethylene and a styrene-based elastomer. The adhesive layer 20 may contain additive components in addition to the above resin components.

[0036] The linear low-density polyethylene contained in the adhesive layer 20 is usually copolymerized with an α-olefin having 4 or more carbon atoms and has a linear molecular structure with few long-chain branches due to the introduction of short-chain branches. Examples of α-olefins copolymerized into the linear low-density polyethylene include 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

[0037] The type of linear low-density polyethylene contained in the adhesive layer 20 may be a resin polymerized using a Ziegler-Natta catalyst or a resin polymerized using a single-site catalyst. Linear low-density polyethylene polymerized using a single-site catalyst is preferred because it has a narrow molecular weight distribution and excellent mechanical properties. An example of a single-site catalyst is a metallocene catalyst. An example of a metallocene catalyst is a catalyst containing a metallocene compound that contains a ligand having a cyclopentadienyl skeleton and in which the metal is zirconium, hafnium, or the like.

[0038] Specific examples of the linear low-density polyethylene contained in the adhesive layer 20 include the Harmolex (registered trademark) series manufactured by Japan Polyethylene Corporation and the Nipolon (registered trademark) series manufactured by Tosoh Corporation.

[0039] The adhesive layer 20 may contain one type of linear low-density polyethylene or two or more types of linear low-density polyethylene.

[0040] When the adhesive layer 20 contains one type of linear low-density polyethylene, the flexural modulus of the linear low-density polyethylene is preferably 50 MPa to 250 MPa, more preferably 80 MPa to 230 MPa, and even more preferably 90 MPa to 200 MPa. When the flexural modulus of the linear low-density polyethylene is within the above preferred range, the adhesive layer 20 is flexible and can exhibit adhesiveness to the cyclic olefin resin layer 10.

[0041] The flexural modulus can be measured by a method conforming to JIS K7171:2016 (ISO 178:2010).

[0042] The melt flow rate (MFR) of the linear low-density polyethylene is preferably 0.8 g / 10 min to 2.0 g / 10 min, more preferably 0.9 g / 10 min to 1.8 g / 10 min, as measured (230°C, 21 N load) according to JIS K 7210-1:2014 (ISO 1133-1:2011). If the MFR of the linear low-density polyethylene is within the above preferred range, when the adhesive layer 20 is formed by extrusion molding or the like, the extrudability is relatively stable and molding defects are suppressed, making it easier to stably mold into a film and suppressing molding defects such as burrs in the adhesive layer 20 during molding.

[0043] The melting point of the linear low-density polyethylene is preferably 110°C to 135°C, more preferably 115°C to 132°C.

[0044] The density of linear low-density polyethylene is 0.905 g / cm 3 ~0.940g / cm 3 is preferred, and 0.908 g / cm 3 ~0.930g / cm 3 is more preferred.

[0045] The content of the linear low-density polyethylene in the adhesive layer 20 is preferably 80% by mass to 95% by mass, and more preferably 85% by mass to 90% by mass. When the content of the linear low-density polyethylene is within the above preferred range, the adhesive layer 20 has flexibility and can exhibit adhesion to the cyclic olefin resin layer 10.

[0046] When adhesive layer 20 contains two types of linear low-density polyethylene, it is preferable that one of the linear low-density polyethylenes (first linear low-density polyethylene) has a higher flexural modulus than the other linear low-density polyethylene (second linear low-density polyethylene).

[0047] The flexural modulus of the first linear low-density polyethylene is preferably 150 MPa to 250 MPa, more preferably 160 MPa to 230 MPa, and even more preferably 170 MPa to 200 MPa. The flexural modulus of the second linear low-density polyethylene is preferably 50 MPa to 130 MPa, more preferably 80 MPa to 120 MPa, and even more preferably 90 MPa to 110 MPa. When the flexural moduli of the first linear low-density polyethylene and the second linear low-density polyethylene are each within the above-mentioned preferred ranges, the adhesive layer 20 has sufficient flexibility and can exhibit good adhesion to the cyclic olefin resin layer 10.

[0048] The first linear low density polyethylene preferably has a higher MFR than the second linear low density polyethylene.

[0049] The MFR of the first linear low-density polyethylene is preferably 1.3 g / 10 min to 2.0 g / 10 min, more preferably 1.4 g / 10 min to 1.8 g / 10 min, as measured in accordance with JIS K 7210-1:2014 (230°C, 21 N load). The MFR of the second linear low-density polyethylene is preferably 0.8 g / 10 min to 1.1 g / 10 min, more preferably 0.9 g / 10 min to 1.0 g / 10 min, as measured in accordance with JIS K 7210-1:2014 (230°C, 21 N load). If the MFRs of the first linear low-density polyethylene and the second linear low-density polyethylene are each within the above-mentioned preferred ranges, when the adhesive layer 20 is formed by extrusion molding or the like, extrudability is relatively stable and molding defects are suppressed, making it easier to stably mold into a film and suppressing molding defects such as burrs in the adhesive layer 20 during molding.

[0050] The first linear low-density polyethylene preferably has a higher melting point than the second linear low-density polyethylene. The melting point of the first linear low-density polyethylene is preferably 126°C to 135°C, more preferably 128°C to 132°C. The melting point of the second linear low-density polyethylene is preferably 110°C to 125°C, more preferably 115°C to 120°C.

[0051] The first linear low density polyethylene preferably has a higher density than the second linear low density polyethylene. The density of the first linear low density polyethylene is 0.913 g / cm 3 ~0.940g / cm 3 is preferred, and 0.915 g / cm 3 ~0.930g / cm 3 The density of the second linear low-density polyethylene is more preferably 0.905 g / cm 3 ~0.912g / cm 3 is preferred, and 0.908 g / cm 3 ~0.910g / cm 3 is more preferred.

[0052] The first linear low-density polyethylene and the second linear low-density polyethylene may be contained in any ratio. For example, the content of the first linear low-density polyethylene contained in the adhesive layer 20 is preferably 20% to 70% by mass, more preferably 25% to 60% by mass, and even more preferably 30% to 50% by mass. The content of the second linear low-density polyethylene is preferably 25% to 75% by mass, more preferably 35% to 70% by mass, and even more preferably 45% to 55% by mass.

[0053] The styrene-based elastomer contained in the adhesive layer 20 can function as, for example, a compatibilizer. Examples of the styrene-based elastomer contained in the adhesive layer 20 include copolymers of styrene and aliphatic olefins. Blocks containing styrene constitute hard blocks, and blocks containing aliphatic olefins constitute soft blocks. The higher the styrene content in the molecule, the stronger the adhesive strength that can be exhibited. However, if the styrene content is too high, flexibility is impaired, so the styrene content in the styrene-based elastomer is preferably 10% by mass to 50% by mass, more preferably 12% by mass to 30% by mass, and even more preferably 15% by mass to 20% by mass.

[0054] Specific examples of styrene-based elastomers include one or more of styrene-ethylene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-isoprene-butadiene-styrene block copolymer (SIBS), styrene-ethylene-butylene-olefin crystalline block copolymer (SEBC), and hydrogenated styrene-butadiene rubber (HSBR). Among these, one or more selected from SEBS, SEPS, SEBC, and HSBR are preferred, with SEBS being particularly preferred. SEBS is generally obtained by hydrogenating a styrene-butadiene-styrene block copolymer to convert butadiene units into two ethylene units or butylene units, but it may also be modified or selectively hydrogenated.

[0055] The ratio of linear low-density polyethylene and styrene-based elastomer among the resin components constituting adhesive layer 20 is preferably, for example, 80 to 99 parts by mass of linear low-density polyethylene and 1 to 20 parts by mass of styrene-based elastomer per 100 parts by mass of the resin component.

[0056] The proportion of the linear low-density polyethylene is more preferably 85 to 90 parts by mass, and the proportion of the styrene-based elastomer is more preferably 10 to 15 parts by mass.

[0057] In the adhesive layer 20, the total content of the two components, linear low-density polyethylene and styrene-based elastomer, is preferably 90% by mass or more, more preferably 95% by mass or more, and may be 100% by mass. The adhesive layer 20 may contain resin components or additive components other than the above two components, but the proportion thereof is preferably 10% by mass or less, more preferably 5% by mass or less of the total adhesive layer.

[0058] (Polypropylene resin layer) The polypropylene-based resin layer 30 contains a polypropylene (PP)-based resin and linear low-density polyethylene.

[0059] The polypropylene-based resin contained in the polypropylene-based resin layer 30 may be a homopolymer of propylene or a copolymer with ethylene or at least one α-olefin having 4 to 8 carbon atoms. When the PP-based resin contained in the polypropylene-based resin layer 30 is a copolymer, the copolymer may be a random copolymer or a block copolymer. The polypropylene-based resin layer 30 may contain one type of polypropylene-based resin, or may contain two or more types of polypropylene-based resin layers.

[0060] The polypropylene resin may contain a thermoplastic elastomer or may consist solely of a thermoplastic elastomer. The flexural modulus of the thermoplastic elastomer is preferably, for example, 240 MPa to 650 MPa.

[0061] The linear low-density polyethylene contained in the polypropylene-based resin layer 30 is usually copolymerized with an α-olefin having 4 or more carbon atoms and has a linear molecular structure with few long-chain branches due to the introduction of short-chain branches. Examples of α-olefins copolymerized into the linear low-density polyethylene include 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

[0062] The type of linear low-density polyethylene contained in the polypropylene-based resin layer 30 includes a resin polymerized using a Ziegler-Natta catalyst and a resin polymerized using a single-site catalyst. Linear low-density polyethylene polymerized using a single-site catalyst is preferred because it has a narrow molecular weight distribution and excellent mechanical properties. An example of a single-site catalyst is a metallocene-based catalyst. An example of a metallocene-based catalyst is a catalyst containing a metallocene compound that includes a ligand having a cyclopentadienyl skeleton and in which the metal is zirconium, hafnium, or the like.

[0063] Specific examples of the linear low-density polyethylene contained in the polypropylene-based resin layer 30 include the Nipolon (registered trademark) series manufactured by Tosoh Corporation.

[0064] The flexural modulus of the linear low-density polyethylene contained in the polypropylene-based resin layer 30 is preferably 300 MPa to 450 MPa, more preferably 320 MPa to 420 MPa, and even more preferably 360 MPa to 400 MPa. When the flexural modulus of the linear low-density polyethylene contained in the polypropylene-based resin layer 30 is within the above-mentioned preferred range, the polypropylene-based resin layer 30 can have appropriate flexibility.

[0065] The MFR of the linear low-density polyethylene is preferably 0.9 g / 10 min to 1.25 g / 10 min, and more preferably 1.1 g / 10 min to 1.2 g / 10 min, as measured (230°C, 21 N load) according to JIS K 7210-1:2014. If the MFR of the linear low-density polyethylene is within the above preferred range, when the polypropylene-based resin layer 30 is formed by extrusion molding or the like, the extrudability is relatively stable and molding defects are suppressed, making it easier to stably mold into a film and suppressing molding defects such as burrs in the polypropylene-based resin layer 30 during molding.

[0066] The melting point of the linear low-density polyethylene is preferably 128°C to 135°C, more preferably 130°C to 132°C.

[0067] The density of linear low-density polyethylene is 0.905 g / cm 3 ~0.912g / cm 3 is preferred, and 0.908 g / cm 3 ~0.910g / cm 3 is more preferred.

[0068] The content of the linear low-density polyethylene is preferably 10% by mass to 35% by mass, more preferably 15% by mass to 30% by mass, and even more preferably 20% by mass to 25% by mass. When the content of the linear low-density polyethylene is within the above-mentioned preferred range, the polypropylene-based resin layer 30 has sufficient flexibility and can effectively reduce the risk of breakage when an external force is applied, such as when the polypropylene-based resin layer 30 is dropped.

[0069] The polypropylene-based resin layer 30 preferably contains a polypropylene-based resin and a linear low-density polyethylene in a mass ratio of 90:10 to 60:40, and more preferably 80:20 to 75:25. By setting the blending ratio of the polypropylene-based resin and the linear low-density polyethylene within the above-mentioned preferred range, the polypropylene-based resin layer 30 can exhibit sufficient flexibility.

[0070] The materials constituting each layer of the laminate 1, i.e., the cyclic olefin resin layer 10, the adhesive layer 20, the polypropylene resin layer 30, etc., may contain various additives such as antioxidants, ultraviolet absorbers, antistatic agents, lubricants, antiblocking agents, etc., within the range that does not impair safety and hygiene, in order to improve the appearance of the container, stabilize the quality, and impart other required performance.

[0071] The thickness of each of the cyclic olefin resin layer 10, adhesive layer 20, and polypropylene resin layer 30 is designed appropriately depending on the application of the container to be formed using the laminate 1. For example, the thickness of the cyclic olefin resin layer 10 may be 95 μm to 170 μm, the thickness of the adhesive layer 20 may be 45 μm to 65 μm, and the thickness of the polypropylene resin layer 30 may be 20 μm to 30 μm.

[0072] The method for molding each layer constituting the laminate 1 is not particularly limited, but a T-die molding method, an inflation molding method, etc. can be used. When a T-die molding method is used, after T-die molding, each layer constituting the laminate 1 may be formed into a film (sheet), etc., and then rapidly cooled with a cooling roll. When continuously molding the films, etc. of the layers constituting the laminate 1, it is preferable to wind up the long molded products, such as the films, of the layers constituting the laminate 1 after molding, as this provides excellent productivity.

[0073] The laminate 1 may be laminated with other layers, such as a sealant layer and a substrate, as needed. That is, an adhesive layer or an anchor layer may be interposed between each layer, or the layers may be laminated so as to be in direct contact with each other. The other layers may be a reinforcing layer, a gas barrier layer, a light-shielding layer, a printed layer, or other layers, and one or more layers may be selected as appropriate. The sealant layer is used for heat sealing, and as a packaging material, it is disposed as the innermost layer that comes into contact with the contents. Heat sealing is a method of bonding by melting the sealant layer, but the sealing method is not particularly limited, and examples include hot plate sealing, ultrasonic sealing, high-frequency sealing, and impulse sealing. The substrate may be the outermost surface of the laminate opposite the sealant layer, or it may be laminated inside the outermost surface of the other outermost surface.

[0074] The total thickness of the laminate 1 can be designed appropriately, and from the viewpoint of the balance between required performance (transparency, flexibility) and cost (productivity, material cost), it is, for example, preferably 150 μm to 300 μm, more preferably 190 μm to 250 μm.

[0075] The method for producing the laminate 1 according to this embodiment is not particularly limited, and may be extrusion lamination, dry lamination, co-extrusion, or a combination of two or more of these methods, to appropriately laminate the layers that make up the laminate 1. The thickness of the sealant layer is appropriately designed depending on the application of the container to be molded using the laminate 1, and is not particularly limited, but may be, for example, 5 μm to 150 μm, and preferably 15 μm to 100 μm.

[0076] When manufacturing the laminate 1, the three layers of the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30 are laminated by a co-extrusion method, and these three layers are laminated without an adhesive layer or an anchor agent layer between them.

[0077] The laminate 1 has three layers: a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30. However, as described above, the laminate 1 may have a plurality of any of these layers. For example, the laminate 1 may include five layers, in which the polypropylene resin layer 30, an adhesive layer 20, a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30 are laminated in this order.

[0078] The laminate 1 according to this embodiment includes a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30. The polypropylene resin layer 30 contains a polypropylene resin and a linear low-density polyethylene, and the interlayer adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20 is 25 N / 15 mm or greater. The linear low-density polyethylene contained in the polypropylene resin layer 30 is more effective at imparting flexibility to the polypropylene resin layer 30 than the polypropylene resin, thereby preventing a decrease in the adhesive strength of the adhesive layer 20 to the cyclic olefin resin layer 10. Therefore, even when the adhesive layer 20 is sandwiched between the polypropylene resin layer 30 and the cyclic olefin resin layer 10, the polypropylene resin layer 30 can enhance its adhesiveness to the cyclic olefin resin layer 10, thereby enhancing the adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30. Therefore, the laminate 1 can have excellent interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30.

[0079] The laminate 1 has an interlayer adhesive strength of 25 N / 15 mm or more between the cyclic olefin resin layer 10 and the adhesive layer 20, and therefore can be effectively used as a container material for plastic containers. Furthermore, the laminate 1 contains linear low-density polyethylene in the polypropylene resin layer 30, which enhances the heat resistance of the polypropylene resin layer 30, making it easier to maintain the adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 even when exposed to high temperatures (e.g., approximately 121°C) for a predetermined time (e.g., 20 minutes). Therefore, even after sterilization, the laminate 1 maintains the interlayer adhesive strength required for use before and after sterilization, and therefore can be effectively used as a container material for medical solution bags and the like that require high-pressure steam sterilization.

[0080] The laminate 1 can contain 10% by mass or more of linear low-density polyethylene in the polypropylene-based resin layer 30. Since the flexibility of the polypropylene-based resin layer 30 is increased, the flexibility of the entire laminate 1 can be increased. Therefore, the adhesive layer 20 can exhibit high adhesion to the cyclic olefin-based resin layer 10, and the adhesive strength between the cyclic olefin-based resin layer 10 and the adhesive layer 20 can be further increased. Therefore, the laminate 1 can further increase the interlayer adhesive strength between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30.

[0081] Furthermore, since the polypropylene-based resin layer 30 contains 10% by mass or more of linear low-density polyethylene, the laminate 1 can have high heat resistance. Because the laminate 1 has heat resistance even at high temperatures exceeding 120°C, it can be subjected to high-pressure steam sterilization, and even when high-pressure steam sterilization is performed, a decrease in interlayer adhesive strength can be suppressed.

[0082] In the laminate 1, the flexural modulus of the linear low-density polyethylene contained in the polypropylene-based resin layer 30 can be set to 300 MPa to 450 MPa. This allows the polypropylene-based resin layer 30 to have appropriate flexibility, reducing the risk of breakage when an external force is applied to the laminate 1, such as when it is dropped, and making it easier to maintain the adhesive state between the adhesive layer 20 and the polypropylene-based resin layer 30.

[0083] In the laminate 1, the polypropylene-based resin layer 30 can contain a polypropylene-based resin and a linear low-density polyethylene in a mass ratio of 90:10 to 60:40. This can further increase the adhesiveness of the polypropylene-based resin layer 30 to the cyclic olefin-based resin layer 10, thereby reliably increasing the adhesive strength between the cyclic olefin-based resin layer 10 and the adhesive layer 20. Therefore, the laminate 1 can further increase the interlayer adhesive strength between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30.

[0084] The laminate 1 includes two types of linear low-density polyethylene in the adhesive layer 20, namely, a first linear low-density polyethylene and a second linear low-density polyethylene. The first linear low-density polyethylene in the adhesive layer 20 has a flexural modulus of 150 MPa to 250 MPa, and the second linear low-density polyethylene has a flexural modulus of 50 MPa to 130 MPa. This improves the flexibility of the adhesive layer 20 and enhances the adhesiveness with the cyclic olefin resin layer 10. Therefore, the laminate 1 reduces the risk of breakage when an external force is applied from the outside, such as when dropped, and can easily maintain the adhesive state between the adhesive layer 20 and the polypropylene resin layer 30, while further enhancing the adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20.

[0085] The laminate 1 can have the content of the first linear low-density polyethylene in the adhesive layer 20 be 20% by mass to 65% by mass, and the content of the second linear low-density polyethylene be 30% by mass to 70% by mass. This can improve the flexibility of the adhesive layer 20 and reliably increase the adhesiveness with the cyclic olefin resin layer 10. Therefore, the laminate 1 can reliably reduce the risk of breakage when an external force is applied, can stably maintain the adhesive state between the adhesive layer 20 and the polypropylene resin layer 30, and can reliably increase the adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20.

[0086] In the laminate 1, the adhesive layer 20 can contain a styrene-based elastomer. This can more reliably provide flexibility to the adhesive layer 20. This makes it easier for the laminate 1 to maintain the adhesive state between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30.

[0087] As described above, the laminate 1 has excellent interlayer adhesive strength, and therefore, when used as a container material for plastic containers or the like, it can increase the durability of the plastic containers, making it suitable for use in plastic containers.

[0088] <Plastic containers> Next, a description will be given of a plastic container formed using the laminate 1 according to this embodiment. The plastic container has a storage section for storing the contents, and the storage section can be formed by stacking the cyclic olefin resin layers 10 of the laminate 1 so that they face each other and joining and sealing the peripheries thereof.

[0089] The plastic container can be used as a packaging bag (pouch), tube packaging, etc. When providing a spout on the packaging bag, the spout can be suitably used as long as it can be bonded to the cyclic olefin resin layer 10, which is the sealant layer of the laminate 1 constituting the packaging bag, to ensure hermeticity. The spout is preferably made of a resin that can be heat-sealed to the cyclic olefin resin layer 10 of the laminate 1, and the laminate 1 and the spout are joined by heat sealing. When heat-sealing the laminate 1 and the spout, the spout may be inserted between two laminates 1 stacked together with the cyclic olefin resin layer 10 on the inside and heat-sealed, or a flange or a boat-shaped fusion base may be provided at one end of the spout, and this flange or fusion base may be heat-sealed to the periphery of a hole provided in the laminate 1 or to the cyclic olefin resin layer 10 on the inner surface of the opening of the packaging bag.

[0090] Examples of the contents include pharmaceuticals (medicines), food and beverages, cosmetics, etc. The pharmaceuticals may be substances that have high adsorption or permeability to general resins, such as nitroglycerin, albumin, vitamins, trace elements, and radical scavengers, or may be an aqueous solution containing the pyrazolone derivative edaravone or a pharmaceutically acceptable salt thereof. The pyrazolone derivative may have one or more substituents, such as an alkyl group, an aromatic group, or a halogen atom, on the carbon or nitrogen atom of the pyrazolone. The pyrazolone derivative may form a salt with an organic acid, an inorganic acid, etc.

[0091] The form of the packaging bag is not particularly limited, and can be applied to small bags such as three-sided bags, four-sided bags, seamed bags, gusseted bags, and self-standing bags, as well as large bags such as inner bags for bag-in-boxes and inner bags for drums. The packaging bag can be used, for example, for drug solution bags for storing infusions and the like, blown containers, etc.

[0092] Fig. 2 is a side view showing an example of a plastic container. As shown in Fig. 2, plastic container 100 may have a storage section 110 for storing the contents and an opening 120 for discharging the contents. Storage section 110 can be formed by arranging laminates 1 so that they are stacked facing each other.

[0093] Thus, by forming the storage section using the laminate 1 according to this embodiment, the plastic container can have high durability. Therefore, even if the interlayer adhesive strength of the laminate forming the storage section gradually decreases during long-term storage of contents in the storage section, the plastic container can suppress interlayer separation (delamination), thereby suppressing the occurrence of cracks in the storage section and leakage of the contents. Furthermore, even after sterilization, the plastic container can maintain a high interlayer adhesive strength of the laminate forming the storage section. Therefore, when the plastic container is used as, for example, a drug solution bag, the drug solution can be stored for a long period of time, and a highly reliable drug solution bag can be provided.

[0094] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims. [Example]

[0095] The following examples are provided to further explain the embodiments, but the embodiments are not limited to these examples. Examples 1 to 6 are working examples.

[0096] <Pouch production> [Example 1] A cyclic olefin resin layer-forming composition, an adhesive layer-forming composition, and a polypropylene resin layer-forming composition were prepared to be used in producing each layer constituting the laminate.

[0097] (Preparation of Cyclic Olefin Resin Layer-Forming Composition) Cyclic olefin polymer 1 (ZEONOR®, manufactured by Zeon Corporation, density 1.02 g / cm 3, glass transition temperature: 136°C) and cyclic olefin polymer 2 (ZEONEX (registered trademark), manufactured by Zeon Corporation, density 1.02 g / cm 3 , glass transition temperature: 136°C) were mixed in a ratio of 70% by mass:30% by mass to prepare a composition for forming a cyclic olefin resin layer.

[0098] (Preparation of adhesive layer-forming composition) LLDPE1 (Nipolon®, manufactured by Tosoh Corporation, MFR: 1.4 g / 10 min, density: 0.915 g / cm 3 , flexural modulus: 170 MPa, melting peak temperature: 128 °C), and LLDPE2 (gas-phase metallocene polyethylene "Harmolex (registered trademark), manufactured by Japan Polyethylene Co., Ltd.", MFR: 0.9 g / 10 min, density: 0.908 g / cm 3 A composition for adhesive layer was prepared by blending a styrene-based elastomer (SEBS "Kraton (registered trademark), manufactured by Kraton Corporation", MFR: 22 g / 10 min, styrene content: 12.3 to 14.3 mass%) as a compatibilizer in a ratio of 50 mass%:40 mass%:10 mass%.

[0099] (Preparation of polypropylene-based resin layer-forming composition) Polypropylene-based thermoplastic elastomer (ZELAS®, manufactured by Mitsubishi Chemical Corporation, MFR: 1.6 g / 10 min, density: 0.89 g / cm 3 , flexural modulus: 620 MPa, tensile strength: 43 MPa, tensile elongation: 680%, peak melting temperature: 162 °C) and LLDPE3 (Nipolon (registered trademark), manufactured by Tosoh Corporation, MFR: 1.1 g / 10 min, density: 0.930 g / cm 3 , flexural modulus: 360 MPa, melting peak temperature: 130°C) were mixed in a ratio of 75% by mass:25% by mass to prepare a composition for a polypropylene-based resin layer.

[0100] (Preparation of laminate) Using a T-die type multilayer film forming machine, a cyclic olefin resin layer-forming composition, an adhesive layer-forming composition, and a polypropylene resin layer composition were co-extruded to produce a laminate in which a cyclic olefin resin layer, an adhesive layer, and a polypropylene resin layer were laminated in this order. The thicknesses of the cyclic olefin resin layer, the adhesive layer, and the polypropylene resin layer were 150 μm, 65 μm, and 25 μm, respectively.

[0101] The compositions of the cyclic olefin resin layer, adhesive layer, and polypropylene resin layer constituting the laminate correspond to the compositions of the cyclic olefin resin layer-forming composition, adhesive layer-forming composition, and polypropylene resin layer-forming composition, respectively. The compositions of the cyclic olefin resin layer, adhesive layer, and polypropylene resin layer are shown in Table 1.

[0102] (Pouch production) The innermost layers of the laminate were stacked together, and the outer periphery of the laminate was heat-sealed except for the filling port to produce an infusion bag-shaped pouch with external dimensions of 172 mm x 115 mm. The outer seal width was trimmed to 5 mm, and the pouch was filled with 105 mL of water, after which the filling port was heat-sealed to hermetically seal the pouch.

[0103] [Examples 2 to 6] A laminate and a pouch were produced in the same manner as in Example 1, except that the composition of at least one of the polypropylene-based resin layer and the adhesive layer was changed to the composition shown in Table 1. The compositions of the cyclic olefin-based resin layer, adhesive layer and polypropylene-based resin layer are shown in Table 1.

[0104] <Evaluation of laminate> [Before sterilization] The interlayer adhesive strength and transparency of the laminate of the produced pouches were measured before sterilization.

[0105] (Interlayer adhesion strength) The interlayer adhesive strength between the cyclic olefin resin layer and the polypropylene resin layer was measured using the following procedure. First, five unheat-sealed pouch sheets were cut into 15 mm wide x 150 mm long pieces, and a portion of the interlayer was separated from one edge of the sheet using ethyl acetate. The sheet was unfolded until the interlayer separation length was 20 mm or more, and both ends of the separated layer were attached to the grips of a tensile tester. Next, a tensile load was applied at a pulling rate of 5 mm / min, causing delamination over a length of 30 mm, and the average load (unit: N / 15 mm) was measured. The average load (unit: N / 15 mm) of the five cut sheets was taken as the interlayer adhesive strength between the cyclic olefin resin layer and the polypropylene resin layer. Based on the results of packaging products, an interlayer adhesive strength of 25 N / 15 mm or more was evaluated as "good," and an average interlayer adhesive strength of less than 25 N / 15 mm was evaluated as "poor."

[0106] (transparency) Transparency was evaluated according to the following procedure. According to Transparency Test Method 1 described in Section 7.02, Test Methods for Plastic Pharmaceutical Containers, of the Seventeenth Edition of the Japanese Pharmacopoeia (JP17), five 0.9 cm x 4 cm specimens were cut from the pouch and immersed in water-filled ultraviolet absorption spectrum measurement cells. Using a cell filled with water alone as a control, the light transmittance at a wavelength of 450 nm was measured and recorded using a UV-visible spectrophotometer. Considering that the Pharmacopoeia's standard for plastic aqueous injection containers requires a light transmittance of 55% or more, transparency was evaluated as "good" when the average light transmittance of the five specimens was 65% or greater, and as "poor" when the average light transmittance was less than 65%.

[0107] [After sterilization] The sealed pouch was placed in a high-pressure steam sterilizer and sterilized for 20 minutes at 121° C. After sterilization, the pouch was removed from the high-pressure steam sterilizer and the temperature of the pouch was quickly lowered with cooling water, and the interlayer adhesive strength and transparency of the laminate after sterilization were measured in the same manner as above.

[0108] Table 1 shows the results of measuring the interlayer adhesive strength and transparency of the laminate used to manufacture the pouches of each example.

[0109] [Table 1]

[0110] As shown in Table 1, in Examples 1 to 5, the interlayer adhesive strength of the laminate before and after sterilization increased significantly, and the decrease in transparency before and after sterilization was also suppressed, satisfying the standards for plastic containers for aqueous injections. In Example 6, the interlayer adhesive strength of the laminate before and after sterilization decreased, but was 25 N / 15 mm or more, satisfying the conditions for use. In addition, the decrease in transparency before and after sterilization was also suppressed, satisfying the standards for plastic containers for aqueous injections.

[0111] Therefore, in the laminates of Examples 1 to 6, the polypropylene resin layer contains a polypropylene resin and LLDPE, and the interlayer adhesive strength between the cyclic olefin resin layer and the adhesive layer can be 25 N / 15 mm or more, resulting in excellent interlayer adhesive strength. Therefore, it can be said that the laminates of Examples 1 to 6 can enhance durability when applied to plastic containers. When the plastic container is used as a drug solution bag, it is preferable that the laminate constituting the drug solution bag has high interlayer adhesive strength even after sterilization, because this prevents interlayer separation (delamination) even if the interlayer adhesive strength gradually decreases during long-term storage of the drug solution in the drug solution bag, thereby maintaining the drug solution bag's functionality. Therefore, it can be said that the drug solution bags molded using the laminates of Examples 1 to 6 can store drug solutions for long periods of time. [Explanation of symbols]

[0112] 1. Laminate 10 Cyclic olefin resin layer 20 Adhesive layer 30 Polypropylene resin layer 100 plastic containers

Claims

1. a cyclic olefin resin layer, an adhesive layer, and a polypropylene resin layer laminated in this order; the polypropylene-based resin layer contains a polypropylene-based resin and a linear low-density polyethylene, the adhesive layer contains a styrene-based elastomer, The laminate has an interlayer adhesive strength between the cyclic olefin resin layer and the adhesive layer of 25 N / 15 mm or more.

2. The laminate according to claim 1 , wherein the polypropylene-based resin layer contains 10% by mass or more of the linear low-density polyethylene.

3. 3. The laminate according to claim 2, wherein the linear low-density polyethylene contained in the polypropylene-based resin layer has a flexural modulus of 300 MPa to 450 MPa.

4. 4. The laminate according to claim 2, wherein the polypropylene-based resin layer contains the polypropylene-based resin and the linear low-density polyethylene in a mass ratio of 90:10 to 60:

40.

5. The adhesive layer comprises two types of linear low-density polyethylene; the flexural modulus of one of the linear low-density polyethylenes contained in the adhesive layer is 150 MPa to 250 MPa; 5. The laminate according to claim 4, wherein the other linear low-density polyethylene contained in the adhesive layer has a flexural modulus of 50 MPa to 130 MPa.

6. The content of the linear low-density polyethylene is 20% by mass to 65% by mass, 6. The laminate according to claim 5, wherein the content of the other linear low-density polyethylene is 30% by mass to 70% by mass.

7. a storage section for storing contents, the storage section being arranged so that the laminate according to any one of claims 1 to 6 is overlapped and facing each other; a mouth portion for discharging the contents; A plastic container equipped with

8. 8. The plastic container according to claim 7, wherein the contents are pharmaceuticals.

9. The plastic container according to claim 7 or 8, which is an infusion bag or a blown container.

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