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 adhesion layer comprising an acid-modified polyolefin resin of 30 mass% 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 resin layer, an adhesive layer, and a polypropylene resin layer laminated in this order, wherein the adhesive layer contains 30% by mass or more of an acid-modified polyolefin resin. [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 includes a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30 laminated in this order, and is formed in the shape of a sheet (film).

[0012] The present inventors have noticed that in a laminate 1 in which a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30 are laminated in this order, the flexibility of the adhesive layer 20 affects the interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30. The present inventors have then found that by including a predetermined amount of an acid-modified polyolefin resin in the adhesive layer 20, the flexibility of the adhesive layer 20 can be increased, and the interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 can be improved.

[0013] 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.

[0014] 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.

[0015] (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.

[0016] 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.

[0017] 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.

[0018] [ka]

[0019] 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.

[0020] 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.

[0021] 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).

[0022] [ka]

[0023] 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.

[0024] 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.

[0025] 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.

[0026] [ka]

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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).

[0031] The cyclic olefin resin layer 10 may be the innermost layer in the laminate 1 and may be used as a sealant layer.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] (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 an acid-modified polyolefin resin, and may contain linear low-density polyethylene (LLDPE) and a styrene-based elastomer. The adhesive layer 20 may be substantially composed of an acid-modified polyolefin resin, linear low-density polyethylene, and a styrene-based elastomer. The adhesive layer 20 may contain additive components in addition to the above resin components.

[0037] The acid-modified polyolefin resin contained in the adhesive layer 20 is a polyolefin resin modified with an α,β-unsaturated carboxylic acid. Specific examples of the acid-modified polyolefin resin include copolymers (a) of olefins mainly composed of ethylene, propylene, isobutylene, and styrene with an α,β-unsaturated carboxylic acid or a derivative thereof, and graft polymers (b) in which an α,β-unsaturated carboxylic acid or a derivative thereof is grafted onto a polymer of olefins mainly composed of ethylene, propylene, and styrene.

[0038] Examples of the α,β-unsaturated carboxylic acid or a derivative thereof in the copolymer (a) include acrylic acid, methacrylic acid, methyl methacrylic acid, sodium acrylate, zinc acrylate, vinyl acetate, and glycidyl methacrylate.

[0039] Specific examples of the copolymer (a) include ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethylacrylic acid copolymer, ethylene-sodium acrylate copolymer, and the like.

[0040] Examples of olefin polymers that can be used as the substrate for the graft polymer (b) include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethylacrylic acid copolymer, ethylene-sodium acrylate copolymer, styrene-isoprene copolymer, and styrene-isobutylene copolymer.

[0041] Examples of the α,β-unsaturated carboxylic acid or a derivative thereof to be grafted onto the above-mentioned olefin polymer include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, anhydrides of these acids, and esters of these acids with tetrahydrofurfuryl alcohol, etc.

[0042] The melt flow rate (MFR) of the acid-modified polyolefin resin is preferably 2.0 g / 10 min to 5.5 g / 10 min, more preferably 3.0 g / 10 min to 5.0 g / 10 min, as measured (230°C, 21 N load) according to JIS K 7210-1:2014 (ISO 1133-1:2011). If the MFR is within the above-mentioned preferred range, the adhesive layer 20 can have an appropriate strength. Furthermore, when the adhesive layer 20 is formed by extrusion molding or the like, the extrudability is relatively stable and molding defects are reduced, making it easy to stably mold into a film and reducing molding defects such as burrs during molding.

[0043] The acid-modified polyolefin resin can be produced using the above-mentioned raw materials by a general production method. The acid-modified polyolefin resin can also be obtained as a commercially available product. Specific examples of commercially available acid-modified polyolefin resins include the ZELAS (registered trademark) series manufactured by Mitsubishi Chemical Corporation.

[0044] The content of the acid-modified polyolefin resin in the adhesive layer 20 is 30% by mass or more, preferably 40% to 80% by mass, and more preferably 50% to 70% by mass. If the content of the acid-modified polyolefin resin in the adhesive layer 20 is less than 30% by mass, the adhesive strength of the adhesive layer 20 may be insufficient. If the content of the acid-modified polyolefin resin in the adhesive layer 20 exceeds 80% by mass, the adhesive strength of the adhesive layer 20 will not be significantly improved.

[0045] The acid-modified polyolefin resin preferably has a tensile stress at break of 5 MPa to 15 MPa, more preferably 10 MPa to 13 MPa. If the tensile stress at break is 5 MPa to 15 MPa, the adhesive layer 20 can have sufficient flexibility. The tensile stress at break can be measured by a method in accordance with JIS K 6251:2017 (ISO 037:2011).

[0046] The linear low-density polyethylene used 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 by introducing 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The ratio of the acid-modified polyolefin resin, linear low-density polyethylene, and styrene-based elastomer among the resin components constituting the adhesive layer 20 is preferably, for example, 30 to 65 parts by mass of the acid-modified polyolefin resin, 34 to 50 parts by mass of the linear low-density polyethylene, and 1 to 20 parts by mass of the styrene-based elastomer per 100 parts by mass of the resin components.

[0051] The proportion of the acid-modified polyolefin resin is more preferably 45 to 55 parts by mass, the proportion of the linear low-density polyethylene is more preferably 35 to 45 parts by mass, and the proportion of the styrene-based elastomer is more preferably 5 to 15 parts by mass.

[0052] In the adhesive layer 20, the total content of the three components, acid-modified polyolefin resin, linear low-density polyethylene, and styrene-based elastomer, is preferably 90% by mass or more, more preferably 95% by mass or more, or may be 100% by mass. The adhesive layer 20 may contain resin components or additive components other than the above three components, but the proportion thereof is preferably 10% by mass or less, more preferably 5% by mass or less of the entire adhesive layer.

[0053] (Polypropylene resin layer) The polypropylene-based resin layer 30 contains a polypropylene (PP)-based resin.

[0054] 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.

[0055] The polypropylene resin may also contain a thermoplastic elastomer, which preferably has a flexural modulus of elasticity of, for example, 240 MPa to 650 MPa.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] The laminate 1 according to this embodiment includes a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30, and the adhesive layer 20 contains 30% by mass or more of an acid-modified polyolefin resin. This allows the acid-modified polyolefin resin to enhance the adhesiveness of the adhesive layer 20, thereby enhancing the adhesive strength between the adhesive layer 20 and the cyclic olefin resin layer 10. Therefore, the laminate 1 can have excellent interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30.

[0065] Furthermore, the laminate 1 can maintain high heat resistance even when the adhesive layer 20 contains 30% by mass or more of an acid-modified polyolefin resin. As a result, the laminate 1 can be heat resistant even at high temperatures exceeding 120°C, and therefore can be subjected to high-pressure steam sterilization, and even when high-pressure steam sterilization is performed, a decrease in the interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 can be suppressed.

[0066] In the laminate 1, the adhesive layer 20 can contain 50% by mass to 80% by mass of an acid-modified polyolefin resin. This allows the acid-modified polyolefin resin to further increase the adhesiveness of the adhesive layer 20, thereby further increasing the adhesive strength between the adhesive layer 20 and the cyclic olefin resin layer 10. Therefore, the laminate 1 can improve the interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30.

[0067] In the laminate 1, the adhesive layer 20 can contain linear low-density polyethylene and a styrene-based elastomer, which can provide greater 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.

[0068] In the laminate 1, the adhesive layer 20 can contain SEBS as the styrene-based elastomer. This can more reliably provide flexibility to the adhesive layer 20. Therefore, the laminate 1 can more reliably maintain adhesion between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30.

[0069] 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.

[0070] <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.

[0071] 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.

[0072] 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.

[0073] 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, as a drug solution bag for storing infusions, etc., a blow-molded container, etc.

[0074] 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.

[0075] 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.

[0076] 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]

[0077] The following examples will explain the embodiments in more detail, but the embodiments are not limited to these examples. Example 1 is an example, and Example 2 is a comparative example.

[0078] <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.

[0079] (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.

[0080] (Preparation of adhesive layer-forming composition) Acid-modified polyolefin resin (ZELAS (registered trademark), manufactured by Mitsubishi Chemical Corporation), MFR = 3.5 g / 10 min (measured in accordance with JIS K 7210-1:2014 at a temperature of 230 °C and a load of 21.18 N), density: 0.89 g / cm 3 , tensile stress at break: 10 MPa, melting peak temperature: 157 °C), and LLDPE (gas-phase metallocene polyethylene "Harmolex (registered trademark)" manufactured by Japan Polyethylene Co., Ltd.), density: 0.908 g / cm 3 A composition for adhesive layer was prepared by blending 50% by mass:40% by mass:10% by mass of a styrene-based elastomer (SEBS "Kraton (registered trademark)" manufactured by Kraton Corporation, MFR: 22 g / 10 min, styrene content: 12.3 to 14.3% by mass) as a compatibilizer with styrene-based elastomer (SEBS "Kraton (registered trademark)" manufactured by Kraton Corporation, MFR: 22 g / 10 min, styrene content: 12.3 to 14.3% by mass) as a compatibilizer with a blending ratio of 50% by mass:40% by mass:10% by mass.

[0081] (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) was used as a composition for a polypropylene-based resin layer.

[0082] (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.

[0083] 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.

[0084] (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.

[0085] [Example 2] A laminate and a pouch were produced in the same manner as in Example 1, except that the composition of the adhesive layer was changed to the composition shown in Table 1. The compositions of the cyclic olefin resin layer, adhesive layer, and polypropylene resin layer are shown in Table 1.

[0086] <Evaluation of laminate> [Before sterilization] The interlayer adhesive strength and transparency of the laminate of the produced pouches were measured before sterilization.

[0087] (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."

[0088] (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%.

[0089] [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.

[0090] Table 1 shows the results of measuring the interlayer adhesive strength and transparency of the laminate used to manufacture the pouches of each example.

[0091] [Table 1]

[0092] As can be seen from Table 1, in Example 1, the interlayer adhesive strength of the laminate increased before and after sterilization, and the decrease in transparency was also suppressed, satisfying the standards for plastic containers for aqueous injections. On the other hand, in Example 2, the interlayer adhesive strength of the laminate decreased significantly before and after sterilization, and the transparency also decreased before and after sterilization, failing to satisfy the standards for plastic containers for aqueous injections.

[0093] Therefore, unlike the laminate of Example 2, the laminate of Example 1 contains 50% by mass of an acid-modified polyolefin resin in the adhesive layer, which allows it to have excellent interlayer adhesive strength, and therefore can be said to have improved durability when applied to a plastic container. When the plastic container is used as a drug solution bag, it is preferable for the laminate constituting the drug solution bag to have high interlayer adhesive strength even after sterilization treatment, 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, and the drug solution bag's function can be maintained. Therefore, it can be said that the drug solution bag molded using the laminate of Example 1 can store the drug solution for a long period of time. [Explanation of symbols]

[0094] 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 adhesive layer is a laminate containing 30% by mass or more of an acid-modified polyolefin resin.

2. 2. The laminate according to claim 1, wherein the content of the acid-modified polyolefin resin is 50% by mass to 80% by mass.

3. The laminate according to claim 1 or 2, wherein the adhesive layer contains linear low-density polyethylene and a styrene-based elastomer.

4. 4. The laminate according to claim 3, wherein the styrene-based elastomer comprises a styrene-ethylene-butylene-styrene block copolymer.

5. a storage section for storing contents, the storage section being arranged so that the laminate according to any one of claims 1 to 4 is overlapped and facing each other; a mouth portion for discharging the contents; A plastic container equipped with

6. 6. The plastic container according to claim 5, wherein the contents are pharmaceuticals.

7. 7. The plastic container according to claim 5, wherein the plastic container is a drug solution bag or a blown container.

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