Laminates and plastic containers

Abstract

To provide a laminate capable of having excellent interlayer adhesive strength.SOLUTION: There is provided a laminate which comprises a cyclic olefin-based resin layer, a polypropylene-based resin layer and an adhesive layer for bonding the cyclic olefin-based resin layer and the polypropylene-based resin layer, wherein the polypropylene-based resin layer contains 10 to 50 mass% of an olefin-based thermoplastic elastomer having a flexural modulus of 50 to 200 MPa and the adhesive layer contains 40 to 80 mass% of an olefin-based thermoplastic elastomer having a flexural modulus of 50 to 200 MPa.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to laminates and plastic containers. [Background technology]

[0002] In various fields such as medicine, food, and cosmetics, laminated film-like materials, consisting of multiple resin layers, are used as container materials for plastic containers that hold pharmaceuticals, food products, cosmetics, etc. Plastic containers formed using these laminates are easy to handle and dispose of, and are therefore used, for example, as medicine bags for storing intravenous fluids and other drug solutions.

[0003] As a laminate to be molded into plastic containers such as liquid medicine bags, for example, a multilayer film is disclosed which includes a sealing layer made of polypropylene and an outermost layer containing polypropylene, between which are 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 polymer and a styrene elastomer (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2009 / 066752 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in the multilayer film described in Patent Document 1, the cyclic olefin resin, such as the cyclic polyolefin polymer contained in the cyclic polyolefin layer, does not easily achieve sufficient adhesive strength with the resin composition layer. As a result, the interlayer adhesive strength between the cyclic polyolefin layer and the outermost layer is low, and delamination is likely to occur between these layers.

[0006] One aspect of the present invention aims to provide a laminate having excellent interlayer adhesion strength.

Means for Solving the Problems

[0007] One aspect of the present invention provides a laminate including a cyclic olefin resin layer, a polypropylene resin layer, and an adhesive layer that joins the cyclic olefin resin layer and the polypropylene resin layer, wherein the polypropylene resin layer contains 10% to 50% by mass of an olefin thermoplastic elastomer having a flexural modulus of 50 MPa to 200 MPa, and the adhesive layer contains 40% to 80% by mass of an olefin thermoplastic elastomer having a flexural modulus of 50 MPa to 200 MPa.

Advantages of the Invention

[0008] One aspect of the present invention can provide a laminate having excellent interlayer adhesion strength.

Brief Description of the Drawings

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

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail. For ease of understanding the description, the scales of each member in the drawings may be different from the actual ones. In this specification, "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value, unless otherwise specified.

[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 an annular olefin-based resin layer 10, an adhesive layer 20, and a polypropylene-based resin layer 30, which are laminated in this order, and is formed in a sheet (film) shape.

[0012] The inventor of the present application has noted that in the laminate 1 in which the cyclic olefin-based resin layer 10, the adhesive layer 20, and the polypropylene-based resin layer 30 are laminated in this order, the flexibility of the adhesive layer 20 and the polypropylene-based resin layer 30 affects the interlayer adhesion strength between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30. Then, the inventor of the present application has found that by including a predetermined amount of an olefin-based thermoplastic elastomer having a high flexural modulus in the adhesive layer 20 and the polypropylene-based resin layer 30, respectively, the flexibility of the adhesive layer 20 and the polypropylene-based resin layer 30 can be increased, and the interlayer adhesion strength between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30 can be improved.

[0013] The interlayer adhesion strength refers to the adhesion strength generated between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30 through the adhesive layer 20. The measurement method of the interlayer adhesion strength is not particularly limited as long as it can measure the adhesion strength between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30. For example, the laminate 1 is cut into a predetermined size, and a part of the layer between 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-based resin layer 10 and the polypropylene-based resin layer 30 of the laminate 1 cut into a predetermined size at a predetermined tensile speed (for example, 5 mm / min) to delaminate a predetermined length (for example, 30 mm). The load required for this delamination (unit: N / 15 mm) may be measured as the interlayer adhesion strength. The interlayer adhesion strength may also be the average load of the loads when measured using a plurality of laminates.

[0014] The laminate 1 may have two or more layers each of the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30, or it may have other layers other than the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30.

[0015] (Cylindrical 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 composed of one or more olefin monomers or a polymer in which the double bond is hydrogenated, and at least one of the olefin monomers is a cyclic olefin monomer having a cyclic hydrocarbon skeleton. Examples of cyclic olefin monomers include norbornene compounds. In the following description, "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 bond after ring-opening metathesis polymerization of a norbornene compound, addition polymers consisting of two or more cyclic olefin monomers, and addition polymers obtained by copolymerizing a cyclic olefin monomer with an acyclic olefin monomer. However, single addition polymers of only one cyclic olefin monomer are undesirable. 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, a basic structure of a polymer obtained by hydrogenating a ring-opening metathesis polymer of norbornene compounds is, for example, the following formula (I). That is, the polymer of formula (I) is described as a polymer in which a cyclic skeleton and an ethylene skeleton are arranged alternately. The cyclic skeleton in formula (1) is a 1,3-cyclopentylene skeleton. However, the ring-opening metathesis polymer of norbornene compounds itself does not need to be a copolymer.

[0018] [Chemical formula]

[0019] In formula (I), n is an integer of 1 or more, and R 1 and R 2 represent a hydrogen atom or an alkyl group. R 1 and R 2 may be the same as or different from each other. R 1 and R 2 may be bonded to each other to form a ring.

[0020] The structure shown in the above formula (I) is not limited to the case where the substituents R 1 and R 2 are the same as each other and the ring-opening metathesis polymer of the norbornene compound is a homopolymer.

[0021] The structure shown in the above formula (I) may also be a polymer obtained by hydrogenating the ring-opening metathesis polymers of two or more norbornene compounds. Examples of such a polymer include the following formula (II).

[0022] [Chemical formula]

[0023] In formula (II), m and n are integers of 1 or more, and R 1 and R 2 represent a hydrogen atom or an alkyl group. m and n may be the same as or different from each other. R 1 and R 2 may be the same as or different from each other. R 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, for example, "ZEONEX® 690R" and "ZEONOR® 1020R" manufactured by Nippon Zeon Corporation.

[0025] Furthermore, an addition polymer obtained by copolymerizing a cyclic olefin monomer and an acyclic olefin monomer is shown in formula (III) below. The addition polymer of formula (III) below is described as a polymer in which the cyclic skeleton and ethylene skeleton are randomly arranged. The cyclic skeleton in formula (I1I) below is the 2,3-norbornylene skeleton.

[0026] [ka]

[0027] In equation (III), m and n are integers greater than or equal to 1, 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. 1 , R 2 and R 3 They may be the same or they may be different. 1 and R 2 These elements may be joined to each other to form a ring.

[0028] R 1 , R 2 and R 3 Examples of polymers in which all atoms are hydrogen atoms include "TOPAS (registered trademark)" manufactured by Polyplastics Co., Ltd. Also, R 1 and R 2 is an alkyl group, R 3 Examples of polymers in which hydrogen atoms are present include "Apel®" manufactured by Mitsui Chemicals, Inc.

[0029] These cyclic olefin resins exhibit excellent water vapor barrier properties and are readily 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 it 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 they may be one or more cyclic olefin resins corresponding to two or more of the above formulas (I) to (III). The two or more cyclic olefin resins may also include cyclic olefin resins that do not correspond to the above formulas (I) to (III).

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

[0032] Commercially available cyclic olefin resins, some of which overlap with the above, include ZEONEX (registered trademark) (manufactured by Nippon Zeon Co., Ltd., a hydrogenated polymer of ring-opening metathesis polymer of norbornene monomers), ZEONOR (registered trademark) (manufactured by Nippon Zeon Co., Ltd., a copolymer based on 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 polar groups derived from dicyclopentadiene and methacrylate esters).

[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 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, as well as 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. In particular, it is preferable that 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 versions thereof (e.g., SEBS, SEPS, etc.), and styrene-butadiene random copolymer are contained in the cyclic olefin resin layer 10 in an amount ranging from 0.05% to 20% by mass.

[0034] By including other resin components, the cyclic olefin resin layer 10 can improve the desired performance of the plastic container, such as impact resistance at low temperatures, maintaining transparency immediately after high-pressure steam sterilization, and improving flexibility.

[0035] The cyclic olefin resin layer 10 preferably consists only of a cyclic olefin resin (it may also contain additives other than resins), and may contain 100% by mass of the cyclic olefin resin (it may not contain any other additives). If other resin components are included, it is preferable that the cyclic olefin resin layer has a cyclic olefin resin as its main component. That is, the cyclic olefin resin layer 10 preferably contains 50% by mass or more of one type of cyclic olefin resin or a total of two or more types of cyclic olefin resins, and particularly preferably contains 70% by mass or more. If the composition ratio of the cyclic olefin resin is low, trace components and drug components with high affinity to plastics may be adsorbed, which may result in insufficient storage stability of the contained drug components.

[0036] (adhesive layer) The adhesive layer 20 is an intermediate layer for joining the cyclic olefin resin layer 10 and the polypropylene resin layer 30. The adhesive layer 20 contains an olefin thermoplastic elastomer (TPO) with a flexural modulus of 50 MPa to 200 MPa, and may also contain linear low-density polyethylene (LLDPE) and a styrene elastomer. The adhesive layer 20 may substantially consist of an olefin thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa, linear low-density polyethylene, and a styrene elastomer. In addition to the resin components described above, the adhesive layer 20 may also contain additive components.

[0037] Examples of olefin-based thermoplastic elastomers included in the adhesive layer 20, having a flexural modulus of 50 MPa to 200 MPa, include copolymers having an olefin-based polymer (resin component) such as polyethylene (PE) or polypropylene (PP) as a molecularly restricting component (hard segment), and an olefin-based rubber component such as ethylene-propylene-diene ternary copolymer (EPDM) or ethylene-propylene rubber (EPR) as a flexible component (soft segment) exhibiting rubber elasticity.

[0038] The flexural modulus of the olefin-based thermoplastic elastomer contained in the adhesive layer 20 is 50 MPa to 200 MPa, preferably 100 MPa to 180 MPa, and more preferably 110 MPa to 160 MPa. If the flexural modulus is less than 50 MPa, the flexibility of the adhesive layer 20 may be insufficient. If the flexural modulus exceeds 200 MPa, sufficient bonding with the cyclic olefin-based resin layer 10 may not be achieved. The flexural modulus can be measured by a method conforming to JIS K 7171:2008 (ISO 178:2001).

[0039] The adhesive layer 20 contains an olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa, thereby increasing the adhesion strength with the cyclic olefin resin layer 10 and reducing the risk of damage when external forces such as drops are applied. The content of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa in the adhesive layer 20 is 40% to 80% by mass, preferably 50% to 70% by mass, and more preferably 55% to 65% by mass. If the content of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa in the adhesive layer 20 is less than 40% by mass, the flexibility of the adhesive layer 20 may be insufficient. If the content of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa in the adhesive layer 20 exceeds 80% by mass, sufficient bonding with the cyclic olefin resin layer 10 may not be achieved.

[0040] The olefin-based thermoplastic elastomer, having a flexural modulus of 50 MPa to 200 MPa, preferably has a tensile strength of 15 MPa to 40 MPa, more preferably 18 MPa to 30 MPa, and even more preferably 20 MPa to 26 MPa. If the tensile strength is 15 MPa to 40 MPa, the adhesive layer 20 can have sufficient flexibility and sufficient adhesion to the cyclic olefin-based resin layer 10. The tensile strength can be measured by a method in accordance with JIS K 7161-1:2014 (ISO 527-1:2012).

[0041] Examples of olefin-based thermoplastic elastomers include Zelus® MC119, MC123, MC638, MC743, and Thermolan®, all manufactured by Mitsubishi Chemical Corporation. Among these, Zelus® MC743 is preferred.

[0042] The linear low-density polyethylene used in the adhesive layer 20 is typically copolymerized with α-olefins having 4 or more carbon atoms, and short-chain branching is introduced to create a linear molecular structure with fewer long-chain branches. Examples of α-olefins copolymerized with linear low-density polyethylene include 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

[0043] Examples of linear low-density polyethylene included in the adhesive layer 20 include resins polymerized using a Ziegler-Natta catalyst and resins 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. Examples of single-site catalysts include metallocene catalysts. Examples of metallocene catalysts include catalysts containing a metallocene compound that includes a ligand having a cyclopentadienyl skeleton and in which the metal is zirconium, hafnium, etc.

[0044] The styrene-based elastomer contained in the adhesive layer 20 can function, for example, as a compatibilizer. Examples of styrene-based elastomers 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 can be. However, if the styrene content is too high, flexibility is impaired, so the styrene content in the styrene-based elastomer is preferably 10% to 50% by mass, more preferably 12% to 30% by mass, and even more preferably 15% to 20% by mass.

[0045] Specific examples of styrene-based elastomers include one or more of the following: 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), hydrogenated styrene-butadiene rubber (HSBR), etc. Among these, one or more selected from SEBS, SEPS, SEBC, and HSBR are preferred, with SEBS being particularly preferred. Generally, SEBS is obtained by hydrogenating styrene-butadiene-styrene block copolymer to convert the butadiene unit into two ethylene units or a butylene unit, but modified or selectively hydrogenated versions are also acceptable.

[0046] In the resin components constituting the adhesive layer 20, the ratio of olefin-based thermoplastic elastomer, linear low-density polyethylene, and styrene-based elastomer is preferably such that, for example, per 100 parts by mass of the resin components, the olefin-based thermoplastic elastomer is 30 to 65 parts by mass, the linear low-density polyethylene is 34 to 50 parts by mass, and the styrene-based elastomer is 1 to 20 parts by mass.

[0047] It is more preferable that the proportion of olefin-based thermoplastic elastomer be 45 to 55 parts by mass, the proportion of linear low-density polyethylene be 35 to 45 parts by mass, and the proportion of styrene-based elastomer be 5 to 15 parts by mass.

[0048] In the adhesive layer 20, the total content of the three components, olefin-based thermoplastic elastomer, 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 also contain resin components or additive components other than the three components mentioned above, but the proportion of these is preferably 10% by mass or less of the total adhesive layer, and more preferably 5% by mass or less.

[0049] (Polypropylene resin layer) The polypropylene resin layer 30 contains a polypropylene (PP) resin and an olefin-based thermoplastic elastomer (TPO) with a flexural modulus of 50 MPa to 200 MPa.

[0050] The polypropylene resin contained in the polypropylene resin layer 30 may be a homopolymer of propylene, or a copolymer of ethylene or at least one α-olefin having 4 to 8 carbon atoms. If the PP resin contained in the polypropylene resin layer 30 is a copolymer, the copolymer may be a random copolymer or a block copolymer. The polypropylene resin layer 30 may contain one type of polypropylene resin, or it may contain two or more polypropylene resin layers.

[0051] Furthermore, the polypropylene resin may contain a thermoplastic elastomer. The thermoplastic elastomer preferably has a different flexural modulus than the olefin-based thermoplastic elastomer, which has a flexural modulus of 50 MPa to 200 MPa. The flexural modulus of the thermoplastic elastomer is preferably, for example, 240 MPa to 650 MPa.

[0052] In other words, when the polypropylene resin is a thermoplastic elastomer, the polypropylene resin layer 30 contains two or more thermoplastic elastomers with different flexural moduli, one of which is an olefin-based thermoplastic elastomer with a flexural moduli of 50 MPa to 200 MPa.

[0053] The olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa contained in the polypropylene resin layer 30 is the same as the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa contained in the adhesive layer 20. Therefore, details of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa contained in the adhesive layer 20 are omitted.

[0054] The polypropylene resin layer 30 contains an olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa, thereby reducing the risk of breakage when external forces such as drops are applied. The content of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa in the polypropylene resin layer 30 is 10% to 50% by mass, preferably 15% to 45% by mass, and more preferably 25% to 35% by mass. If the content of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa in the polypropylene resin layer 30 is less than 10% by mass, the flexibility of the polypropylene resin layer 30 may be insufficient. If the content of the olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa in the polypropylene resin layer 30 exceeds 50% by mass, sufficient bonding with the adhesive layer 20 may not be achieved.

[0055] The polypropylene resin layer 30 contains polypropylene resin and an olefin-based thermoplastic elastomer having a flexural modulus of 50 MPa to 200 MPa in a mass ratio of 90:10 to 60:40, preferably 80:20 to 65:35, and more preferably 75:25 to 70:30.

[0056] Each layer constituting the laminate 1, i.e., the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30, etc., may contain various additives such as antioxidants, ultraviolet absorbers, antistatic agents, lubricants, and antiblocking agents, to the extent that safety and hygiene are not compromised, in order to improve the appearance of the container, stabilize its quality, and provide other necessary performance.

[0057] The thickness of each layer—the cyclic olefin resin layer 10, the adhesive layer 20, and the polypropylene resin layer 30—is appropriately designed for the intended use of the container molded 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 forming each layer constituting the laminate 1 is not particularly limited, but methods such as T-die molding and inflation molding can be used. When using T-die molding, after T-die molding, each layer constituting the laminate 1 may be made into a film (sheet) and then rapidly cooled with a cooling roll. When continuously forming the films of each layer constituting the laminate 1, it is preferable to wind up the long molded body of the films of each layer constituting the laminate 1 after molding, as this improves productivity.

[0059] Laminate 1 may have a sealant layer and other layers such as a substrate, as needed. That is, there may be an adhesive layer or an anchoring agent layer between each layer, or the layers may be laminated so that they are in direct contact with each other. Other layers may include a reinforcing layer, a gas barrier layer, a light-shielding layer, a printing layer, etc., and one or more layers can be selected as appropriate. The sealant layer is a layer used for heat sealing and is placed as the innermost layer in contact with the contents in the packaging material. 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 to the sealant layer, or it may be laminated inside the outermost surface of the other.

[0060] The total thickness of the laminate 1 can be designed as appropriate, and from the viewpoint of balancing the required performance (transparency, flexibility) and cost (productivity, material cost), for example, 150 μm to 300 μm is preferred, and 190 μm to 250 μm is more preferred.

[0061] The manufacturing method for the laminate 1 according to this embodiment is not particularly limited, and each layer constituting the laminate 1 may be appropriately laminated by an extrusion lamination method, a dry lamination method, a co-extrusion method, or a combination of two or more of these methods. The thickness of the sealant layer is appropriately designed according to the intended use of the container 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 the laminate 1 is manufactured, if the three layers of the cyclic olefin resin layer 10, adhesive layer 20, and polypropylene resin layer 30 are laminated using a co-extrusion method, the layers are laminated without an adhesive layer or anchoring agent layer in between.

[0063] 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, it may have multiple of any of these layers. For example, laminate 1 may include five layers in which the cyclic olefin resin layer 10, adhesive layer 20, polypropylene resin layer 30, adhesive layer 20, and cyclic olefin resin layer 10 are laminated in this order.

[0064] The laminate 1 according to this embodiment comprises a cyclic olefin resin layer 10, an adhesive layer 20, and a polypropylene resin layer 30. The adhesive layer 20 contains 40% to 80% by mass of an olefin thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa, and the polypropylene resin layer 30 contains 10% to 50% by mass of an olefin thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa. The adhesive layer 20 and the polypropylene resin layer 30 have high flexibility and can enhance adhesion to the cyclic olefin resin layer 10, thereby increasing the adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20. 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 have high heat resistance because the adhesive layer 20 contains 40% to 80% by mass of an olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa, and the polypropylene resin layer 30 contains 10% to 50% by mass of an olefin-based thermoplastic elastomer with a flexural modulus of 50 MPa to 200 MPa. Since the laminate 1 can withstand temperatures exceeding 120°C, it can be subjected to high-pressure steam sterilization, and the reduction in interlayer adhesion strength can be suppressed even when high-pressure steam sterilization is performed.

[0066] Laminate 1 can achieve an interlayer adhesion strength of 25 N / 15 mm or more between the cyclic olefin resin layer 10 and the adhesive layer 20. This allows laminate 1 to be effectively used as a container material for plastic containers. Furthermore, even after sterilization, laminate 1 maintains the required interlayer adhesion strength before and after sterilization, making it effectively usable as a container material for chemical bags and other items requiring high-pressure steam sterilization.

[0067] In laminate 1, the adhesive layer 20 may contain linear low-density polyethylene and a styrene-based elastomer. This allows the adhesive layer 20 to be more flexible. Therefore, laminate 1 can more easily maintain its adhesive state with the cyclic olefin resin layer 10 and the polypropylene resin layer 30.

[0068] The laminate 1 may include SEBS as a styrene-based elastomer in its adhesive layer 20. This allows the adhesive layer 20 to be more reliably flexible. Therefore, the laminate 1 can more reliably maintain adhesion between the cyclic olefin resin layer 10 and the polypropylene resin layer 30.

[0069] As described above, laminate 1 has excellent interlayer adhesion strength, and therefore, if used as a container material for plastic containers, it can enhance the durability of plastic containers, and thus can be suitably used for plastic containers.

[0070] <Plastic containers> Next, a plastic container formed using the laminate 1 according to this embodiment will be described. The plastic container has a storage compartment for storing contents, and the storage compartment can be formed by overlapping the cyclic olefin resin layers 10 of the laminate 1 so that they face each other, and then joining their peripheries to seal it.

[0071] Plastic containers can be used as packaging bags (pouches), tube packaging, etc. When a spout is provided in a packaging bag, the spout can be suitably used as long as it can be joined to the cyclic olefin resin layer 10, which is the sealant layer of the laminate 1 that constitutes the packaging bag, to ensure airtightness. It is preferable to use a spout made of a heat-sealable resin and the cyclic olefin resin layer 10 of the laminate 1, and to join the laminate 1 and the spout by heat sealing. When heat sealing the laminate 1 and the spout, the spout may be inserted between the laminate 1 stacked with the cyclic olefin resin layer 10 on the inside and then heat-sealed, or a flange portion or a boat-shaped fusion base may be provided at one end of the spout, and this flange portion or fusion base may be heat-sealed to the periphery of a hole in the laminate 1 or to the cyclic olefin resin layer 10 on the inner surface of the opening of the packaging bag.

[0072] The contents may include pharmaceuticals (drugs), food and beverages, cosmetics, etc. Pharmaceuticals may be substances with high adsorption or permeability to general resins, such as nitroglycerin, albumin, vitamins, trace elements, and radical scavengers, or they may be aqueous solutions containing edaravone, a pyrazolone derivative, or a pharmaceutically acceptable salt thereof. Pyrazolon derivatives may have one or more substituents such as alkyl groups, aromatic groups, or halogen atoms on the carbon or nitrogen atom of pyrazolone. Pyrazolon derivatives may also form salts with organic acids, inorganic acids, 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, gusseted bags, 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 medicine bag for containing intravenous fluids, a blow-molded container, etc.

[0074] Figure 2 is a side view showing an example of a plastic container. As shown in Figure 2, the plastic container 100 may have a storage section 110 for storing contents and an opening 120 for discharging contents. The storage section 110 can be formed by arranging the laminated bodies 1 to overlap each other so that they face each other.

[0075] Thus, the plastic container can have high durability because the storage portion is formed by the laminate 1 according to this embodiment. Therefore, even if the interlayer adhesion strength of the laminate forming the storage portion gradually decreases while the contents are stored in the storage portion of the plastic container for a long period of time, delamination can be suppressed, thus preventing cracks from forming in the storage portion and leakage of the contents. Furthermore, the plastic container can maintain a high level of interlayer adhesion strength of the laminate forming the storage portion even after sterilization. Therefore, when the plastic container is used, for example, as a drug solution bag, the drug solution can be stored for a long period of time, thus providing a highly reliable drug solution bag.

[0076] As described above, embodiments have been explained, but these embodiments are presented as examples only, and the present invention is not limited by these embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, and modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Examples]

[0077] The embodiments will be described in more detail below with reference to examples, but the embodiments are not limited to these examples. Examples 1 and 2 are examples, and Example 3 is a comparative example.

[0078] <Pouch preparation> [Example 1] We prepared compositions for forming cyclic olefin resin layers, adhesive layers, and polypropylene resin layers, which are used to create each layer constituting the laminate.

[0079] (Preparation of compositions for forming cyclic olefin resin layers) Cyclic olefin polymer 1 (ZEONOR® registered trademark) 1020R (manufactured by Zeon Corporation, density 1.02 g / cm³) 3 (Glass transition temperature: 136℃) and cyclic olefin polymer 2 (ZEONEX® 1020R (manufactured by Nippon Zeon Co., Ltd., density 1.02 g / cm³) 3 A composition for forming a cyclic olefin resin layer was prepared by blending (glass transition temperature: 136°C) in a ratio of 70% by mass:30% by mass.

[0080] (Preparation of compositions for forming adhesive layers) Olefin-based thermoplastic elastomer (Zelus® MC743 (manufactured by Mitsubishi Chemical Corporation), MFR: 1.7g / 10min, Density: 0.89g / cm³) 3 (Flexural modulus: 110 MPa, Tensile strength: 18 MPa, Tensile elongation: 750%, Melting peak temperature: 161°C) and LLDPE (Gas-phase metallocene polyethylene "Harmolex® NF325N" (manufactured by Nippon Polyethylene Co., Ltd.), Density: 0.908 g / cm³) 3 A composition for adhesive layers was prepared by blending a styrene-based elastomer (SEBS "Krayton® G1657VS (manufactured by Kraton Corporation)", MFR: 22 g / 10 min, styrene content: 12.3-14.3% by mass) as a compatibilizer in a ratio of 50% by mass:40% by mass:10% by mass.

[0081] (Preparation of compositions for forming polypropylene resin layers) Polypropylene-based thermoplastic elastomer (Zelus® 7025 (manufactured by Mitsubishi Chemical Corporation), MFR: 1.6g / 10min, Density: 0.89g / cm³) 3(Flexural modulus: 620 MPa, Tensile strength: 43 MPa, Tensile elongation: 680%, Melting peak temperature: 162°C) and olefin-based thermoplastic elastomer (Zelus® MC743 (manufactured by Mitsubishi Chemical Corporation), MFR: 1.7 g / 10 min, Density: 0.89 g / cm³) 3 A polypropylene resin layer composition was prepared by mixing (flexural modulus: 110 MPa, tensile strength: 18 MPa, tensile elongation: 750%, melting peak temperature: 161°C) in a ratio of 75% by mass to 25% by mass.

[0082] (Fabrication of laminates) Using a T-die multilayer film manufacturing machine, a laminate was fabricated by co-extrusion of a cyclic olefin resin layer-forming composition, an adhesive layer-forming composition, and a polypropylene resin layer-forming composition, with the cyclic olefin resin layer, adhesive layer, and polypropylene resin layer being laminated in that order. The thicknesses of the cyclic olefin resin layer, adhesive layer, and polypropylene resin layer were 150 μm, 65 μm, and 25 μm, respectively.

[0083] The composition of each layer constituting the laminate—the cyclic olefin resin layer, the adhesive layer, and the polypropylene resin layer—corresponds to the compositions of the cyclic olefin resin layer forming composition, the adhesive layer forming composition, and the polypropylene resin layer forming composition, respectively. The compositions of the cyclic olefin resin layer, the adhesive layer, and the polypropylene resin layer are shown in Table 1.

[0084] (Preparation of pouches) Using the manufactured laminate, the innermost layers were stacked together, and the outer circumference of the laminate was heat-sealed except for the filling opening to create an infusion bag-shaped pouch with outer dimensions of 172 mm x 115 mm. The outer circumference was trimmed to a seal width of 5 mm, 105 mL of water was filled into the pouch, and then the filling opening was heat-sealed to seal the pouch.

[0085] [Examples 2 and 3] In Example 1, the laminate and pouch were prepared in the same manner as in Example 1, except that the composition of the polypropylene resin 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 laminates> [Before sterilization] The interlayer adhesion strength and transparency of the laminated structure of the fabricated pouches were measured before sterilization.

[0087] (Interlayer adhesion strength) The interlayer adhesion strength between the cyclic olefin resin layer and the polypropylene resin layer was measured using the following procedure. First, five 15mm wide x 150mm long pieces were cut from the unheat-sealed sheet of the pouch, and a portion of the interlayer was separated from one end of the sheet using ethyl acetate. The sheet was unfolded until the separated length was 20mm or more, and both ends of the separated interlayer were attached to the grips of a tensile testing machine. Next, a tensile load was applied at a tensile speed of 5mm / min, and a 30mm length of interlayer delamination was achieved. The average load (unit: N / 15mm) was measured. The average load (unit: N / 15mm) of the five cut sheets was taken as the interlayer adhesion strength between the cyclic olefin resin layer and the polypropylene resin layer. Based on the performance of the packaging product, an interlayer adhesion strength of 25N / 15mm or higher was evaluated as "good," and an average interlayer adhesion strength of less than 25N / 15mm was evaluated as "poor."

[0088] (transparency) Transparency was evaluated using the following procedure. Following the transparency test method 1 described in section 7.02 of the Japanese Pharmacopoeia, 17th edition (JP17), five 0.9 cm x 4 cm samples were cut from the pouch portion of the laminate, immersed in a UV absorption spectrum measurement cell filled with water, and the light transmittance at a wavelength of 450 nm was measured and recorded using a UV-Vis spectrophotometer with a cell filled only with water as a control. Considering that the specifications for plastic aqueous injection containers in the same Pharmacopoeia require a light transmittance of 55% or higher, transparency was evaluated as "good" if the average value of the measured light transmittance of the five samples was 65% or higher, and transparency was evaluated as "poor" if the average value of the measured light transmittance was less than 65%.

[0089] [After sterilization] The sealed pouches were placed in an autoclaved steam sterilizer and sterilized at 121°C for 20 minutes. After sterilization, the pouches were removed from the autoclaved steam sterilizer, and their temperature was rapidly reduced with cooling water. The interlayer adhesion strength and transparency of the laminate after sterilization were measured in the same manner as described above. In Example 1, the transparency of the laminate was measured not only immediately after sterilization but also one week after sterilization.

[0090] Table 1 shows the measurement results for interlayer adhesion strength and transparency of the laminates used in the manufacture of each example pouch.

[0091] [Table 1]

[0092] Table 1 shows that in Example 1, the interlayer adhesion strength of the laminate increased significantly before and after sterilization, and the decrease in transparency was suppressed before and after sterilization, meeting the specifications for plastic aqueous injection containers. In Example 2, the interlayer adhesion strength of the laminate decreased before and after sterilization, but it was still 25N / 15mm or higher, meeting the usage conditions. Furthermore, the decrease in transparency was suppressed before and after sterilization, meeting the specifications for plastic aqueous injection containers. On the other hand, in Example 3, the interlayer adhesion strength of the laminate decreased significantly before and after sterilization, and the transparency also decreased before and after sterilization, failing to meet the specifications for plastic aqueous injection containers.

[0093] Therefore, unlike the laminate in Example 3, the laminates of Example 1 and Example 2, by containing predetermined amounts of olefin-based thermoplastic elastomer with a flexural modulus of 110 MPa in the adhesive layer and polypropylene resin layer, respectively, can have excellent interlayer adhesion strength, and thus can be said to enhance durability when applied to plastic containers. When a plastic container is used as a drug solution bag, if the laminate constituting the drug solution bag has high interlayer adhesion strength even after sterilization, it is preferable that interlayer separation (delamination) is suppressed even if the interlayer adhesion strength gradually decreases during long-term storage of the drug solution in the drug solution bag, thereby maintaining the function of the drug solution bag. Therefore, it can be said that drug solution bags molded using the laminates of Example 1 and Example 2 can store drug solutions 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, Polypropylene resin layer, An adhesive layer that joins the cyclic olefin resin layer and the polypropylene resin layer, Equipped with, The polypropylene resin layer contains 10% to 50% by mass of an olefin-based thermoplastic elastomer having a flexural modulus of 50 MPa to 200 MPa. The adhesive layer is a laminate containing 40% to 80% by mass of an olefin-based thermoplastic elastomer having a flexural modulus of 50 MPa to 200 MPa.

2. The laminate according to claim 1, wherein the interlayer adhesive strength between the cyclic olefin resin layer and the adhesive layer is 25 N / 15 mm or more.

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

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

5. The polypropylene resin layer comprises a thermoplastic elastomer having a different flexural modulus than the olefin-based thermoplastic elastomer, The laminate according to claim 1 or 2, wherein the flexural modulus of the thermoplastic elastomer is 240 MPa to 650 MPa.

6. A storage compartment for storing contents, wherein the laminates described in any one of claims 1 to 5 are arranged to overlap each other so as to face each other, An opening for discharging the contents, A plastic container equipped with [a specific feature / feature].

7. The plastic container according to claim 6, wherein the contents are a pharmaceutical product.

8. The plastic container according to claim 6 or 7, wherein the plastic container is a liquid medicine bag or a blow-molded container.

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