JP2023066723A - Laminates and plastic containers - Google Patents

Abstract

A laminate having excellent interlayer adhesive strength is provided.
A laminate according to the present invention comprises a cyclic olefin-based resin layer, an adhesive layer and a polypropylene-based resin layer laminated in this order, and the polypropylene-based resin layer comprises a polypropylene-based resin and a linear low-density polyethylene. and the interlayer adhesive strength between the cyclic olefin resin layer and the adhesive layer is 25 N/15 mm or more.
[Selection drawing] Fig. 1

Description

The present invention relates to laminates and plastic containers.

BACKGROUND ART In various fields such as the medical field, the food field, and the cosmetic field, film-like laminates in which a plurality of resin layers are laminated are used as container materials for plastic containers filled with pharmaceuticals, foodstuffs, cosmetics, and the like. A plastic container formed using a laminate is easy to handle and easy to dispose of, so that it is used, for example, as a drug solution bag for containing a drug solution such as an infusion solution.

As a laminate molded into a plastic container such as a drug solution bag, for example, a cyclic polyolefin layer made of a cyclic polyolefin polymer or a cyclic polyolefin copolymer and a propylene-based polymer are placed between a sealing layer made of polypropylene and an outermost layer containing polypropylene. A multilayer film including a resin composition layer comprising a blend of coalescence and a styrenic elastomer has been disclosed (see, for example, Patent Document 1).

WO2009/066752

However, in the multilayer film of Patent Document 1, the cyclic olefin-based resin such as cyclic polyolefin polymer contained in the cyclic polyolefin layer is difficult to obtain adhesion strength to the resin composition layer. There is a problem in that the interlayer adhesion strength is low, and peeling is likely to occur between these layers.

An object of one aspect of the present invention is to provide a laminate that can have excellent interlayer adhesive strength.

One aspect of the present invention includes 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 includes a polypropylene-based resin and a linear low-density polyethylene, and the cyclic Provided is a laminate in which the interlayer adhesive strength between the olefin resin layer and the adhesive layer is 25 N/15 mm or more.

One aspect of the present invention can provide a laminate that can have excellent interlayer adhesion strength.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the structure of the laminated body which concerns on embodiment of this invention. 1 is a side view showing an example of a plastic container; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. In order to facilitate understanding of the description, the scale of each member in the drawings may differ from the actual scale. Unless otherwise specified, "-" indicating a numerical range in this specification means that the numerical values before and after it are included as lower and upper limits.

<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 a laminate according to this embodiment. As shown in FIG. 1, the laminate 1 according to the present embodiment includes a cyclic olefin resin layer 10, an adhesive layer 20 and a polypropylene resin layer 30 laminated in this order, and the cyclic olefin resin layer 10 and the adhesive layer The interlayer adhesive strength with 20 is 25 N/15 mm or more. The laminate 1 is formed in a sheet (film) shape.

Note that the interlayer adhesive strength refers to the adhesive strength generated between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 via the adhesive layer 20 . A method for measuring the interlayer adhesive strength is not particularly limited as long as it is a method capable of measuring the adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 . For example, the laminate 1 is cut into a predetermined size, and a portion between layers 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 (for example, 5 mm/min). Apply and delaminate a predetermined length (eg 30 mm). The load (unit: N/15 mm) required for this peeling may be measured as the interlayer adhesive strength. The interlayer adhesive strength may be an average load of loads measured using a plurality of laminates.

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 the cyclic olefin resin layer 10, the adhesive layer 20 and the polypropylene resin layer 30. You may have other layers than.

(Cyclic olefin resin layer)
The cyclic olefin resin layer 10 mainly contains a cyclic olefin resin. The cyclic olefin-based resin contained in the cyclic olefin-based resin layer 10 is a polymer composed of one or more olefin monomers or a polymer in which the double bonds are hydrogenated, and at least one of the olefin monomers is It is a cyclic olefin monomer having a cyclic hydrocarbon skeleton. Cyclic olefin monomers include, for example, norbornene compounds. In the following description, the term “cyclic olefin-based resin” simply refers to the cyclic olefin-based resin contained in the cyclic olefin-based resin layer 10 .

Cyclic olefin resins are polymers obtained by hydrogenating the remaining double bonds after ring-opening metathesis polymerization of norbornene compounds, addition polymers composed of two or more cyclic olefin monomers, and cyclic olefin monomers and non-cyclic olefin monomers. It includes addition polymers obtained by copolymerizing the above. However, a single addition polymer of only one cyclic olefin monomer is not preferred. Methods for producing cyclic olefin resins include a method of hydrogenating a ring-opening metathesis polymer of a norbornene compound, a method of copolymerizing two or more cyclic olefin monomers, and a method of copolymerizing a cyclic olefin monomer and an α-olefin. method.

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

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 or different. R ¹ and R ² may combine with each other to form a ring.

In the structure shown in the above formula (I), the substituents R ¹ and R ² possessed by the n 1,3-cyclopentylene skeletons are the same, and the ring-opening metathesis polymer of the norbornene compound is a homopolymer (homo polymer).

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

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 or different. R ¹ and R ² may be the same or different. R ¹ and R ² may combine with each other to form a ring.

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

Moreover, the following formula (III) is mentioned as an addition polymer which copolymerized the cyclic olefin monomer and the non-cyclic olefin monomer. The addition polymer of formula (III) below is described as a polymer in which a cyclic skeleton and an ethylene skeleton are randomly arranged. The cyclic skeleton of formula (I1I) below is a 2,3-norbornanylene skeleton.

In formula (III), m and n are integers of 1 or more, and R ¹ , R ² and R ³ each represent 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. R ¹ and R ² may combine with each other to form a ring.

Polymers in which R ¹ , R ² and R ³ are all hydrogen atoms include, for example, TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd., and the like. Examples of polymers in which R ¹ and R ² are alkyl groups and R ³ is a hydrogen atom include APEL (registered trademark) manufactured by Mitsui Chemicals, Inc., and the like.

These cyclic olefin resins have 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-based resin layer 10 may contain one type of cyclic olefin-based resin, or two or more types of cyclic olefin-based resins.

Here, the two or more cyclic olefin-based resins may be two or more cyclic olefin-based resins corresponding to any one of the above formulas (I) to (III), or the formula (I ) to (III) may each contain one or more cyclic olefin resins for each of two or more formulas. The two or more cyclic olefin-based resins may further include cyclic olefin-based resins that do not fall under the above formulas (I) to (III).

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

Examples of commercially available cyclic olefin resins include ZEONEX (registered trademark) (manufactured by Nippon Zeon Co., Ltd., hydrogenated polymer of ring-opening metathesis polymer of norbornene monomer), ZEONOR (registered Trademark) (manufactured by Nippon Zeon Co., Ltd., copolymer based on ring-opening polymerization of dicyclopentadiene and tetracyclopentadodecene), TOPAS (registered trademark) (manufactured by Polyplastics Co., Ltd., copolymer of norbornene and ethylene), APEL (registered trademark) (manufactured by Mitsui Chemicals, Inc., copolymer of ethylene and tetracyclododecene), Arton (registered trademark) (manufactured by JSR Corporation, cyclic olefins containing polar groups made from dicyclopentadiene and methacrylic acid ester) resin) and the like.

The cyclic olefin-based resin layer 10 may contain other resin components in addition to the cyclic olefin-based resin. Other resin components include polyethylene, polypropylene, polybutene, ethylene/α-olefin copolymer, ethylene/(meth)acrylic acid copolymer, ethylene/vinyl acetate copolymer, and ethylene/(meth)acrylic acid ester copolymer. One or more of polyolefin resins such as polymers, urethane resins, rubber resins, polyester resins, polyester urethane resins, acrylic resins, amide resins, styrene resins, silane resins, etc. be done. Among these, examples of styrene-based resins include polystyrene, styrene-acrylonitrile copolymer (SAN), and styrene-based elastomers. Among them, in particular, styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene copolymer, styrene-isoprene-styrene block copolymer (SIS), hydrogenated products thereof ( For example, SEBS, SEPS, etc.), styrene-butadiene random copolymer, etc., is preferably contained in the cyclic olefin resin layer 10 in the range of 0.05% by mass to 20% by mass. .

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

The cyclic olefin-based resin layer 10 preferably contains only a cyclic olefin-based resin as a resin component (may contain additives other than resins), and may contain 100% by mass of the cyclic olefin-based resin (other additives not included). When the other resin components mentioned above are included, it is preferable that the cyclic olefin-based resin layer contains the cyclic olefin-based resin as a main component. That is, the cyclic olefin resin layer 10 preferably contains one cyclic olefin resin or two or more cyclic olefin resins in a total amount of 50% by mass or more, particularly preferably 70% by mass or more. If the composition ratio of the cyclic olefin-based resin is low, trace components and drug components that have a high affinity for plastics may be adsorbed, resulting in insufficient storage stability of the stored drug components.

(adhesion layer)
The adhesive layer 20 is an intermediate layer for bonding the cyclic olefin resin layer 10 and the polypropylene resin layer 30 together. Adhesive layer 20 comprises linear low density polyethylene (LLDPE) and may comprise a styrenic elastomer. Adhesive layer 20 may be substantially composed of linear low density polyethylene and a styrenic elastomer. The adhesive layer 20 may contain additive components in addition to the above resin components.

The linear low-density polyethylene contained in the adhesive layer 20 is usually copolymerized with an α-olefin having 4 or more carbon atoms to introduce short-chain branching, thereby reducing long-chain branching and linear It has a molecular structure. α-Olefins to be copolymerized with linear low-density polyethylene include 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like.

Examples of types of linear low-density polyethylene contained in the adhesive layer 20 include a resin polymerized using a Ziegler-Natta catalyst, a resin polymerized using a single-site catalyst, and the like. A linear low-density polyethylene polymerized using a single-site catalyst is preferable because it has a narrow molecular weight distribution and excellent mechanical properties. Single site catalysts include metallocene catalysts. Examples of metallocene-based catalysts include catalysts containing metallocene compounds containing ligands having a cyclopentadienyl skeleton and metals such as zirconium and hafnium.

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

The linear low-density polyethylene contained in the adhesive layer 20 may be of one type or two or more types.

When only one type of linear low-density polyethylene is contained in the adhesive layer 20, the bending elastic modulus of the linear low-density polyethylene is preferably 50 MPa to 250 MPa, more preferably 80 MPa to 230 MPa. More preferably 90 MPa to 200 MPa. If the flexural modulus of the linear low-density polyethylene is within the above preferred range, the adhesive layer 20 has flexibility and exhibits adhesiveness to the cyclic olefin resin layer 10 .

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

The melt flow rate (MFR) of linear low-density polyethylene is 0.8 g / 10 minutes to 2 in measurement (230 ° C., 21 N load) based on JIS K 7210-1: 2014 (ISO 1133-1: 2011). 0 g/10 min is preferred, and 0.9 g/10 min to 1.8 g/10 min is more preferred. If the MFR of the linear low-density polyethylene is within the above preferable range, when the adhesive layer 20 is formed by extrusion molding or the like, the extrudability is relatively stable, and molding defects are suppressed, so the film is stable. It is possible to suppress the occurrence of molding defects such as burrs in the adhesive layer 20 during molding.

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

The density of linear low-density polyethylene is preferably 0.905 g/cm ³ to 0.940 g/cm ³ , more preferably 0.908 g/cm ³ to 0.930 g/cm ³ .

The content of the linear low-density polyethylene contained in the adhesive layer 20 is preferably 80% to 95% by mass, more preferably 85% to 90% by mass. If the content of the linear low-density polyethylene is within the above preferred range, the adhesive layer 20 has flexibility and exhibits adhesiveness to the cyclic olefin resin layer 10 .

When two types of linear low-density polyethylene are included in the adhesive layer 20, one linear low-density polyethylene (first linear low-density polyethylene) It preferably has a higher flexural modulus than linear low density polyethylene).

The bending elastic modulus of the first linear low-density polyethylene is preferably 150 MPa to 250 MPa, more preferably 160 MPa to 230 MPa, even more preferably 170 MPa to 200 MPa. The bending elastic modulus of the second linear low-density polyethylene is preferably 50 MPa to 130 MPa, more preferably 80 MPa to 120 MPa, even more preferably 90 MPa to 110 MPa. If the flexural elastic moduli of the first linear low-density polyethylene and the second linear low-density polyethylene are within the preferred ranges described above, the adhesive layer 20 has sufficient flexibility and a cyclic olefin-based Good adhesion to the resin layer 10 can be exhibited.

Preferably, the first linear low density polyethylene has a higher MFR than the second linear low density polyethylene.

The MFR of the first linear low-density polyethylene is preferably 1.3 g/10 minutes to 2.0 g/10 minutes in the measurement based on JIS K 7210-1:2014 (230 ° C., 21 N load), and 1.4 g /10 minutes to 1.8 g/10 minutes is more preferable. The MFR of the second linear low-density polyethylene is preferably 0.8 g/10 minutes to 1.1 g/10 minutes in the measurement based on JIS K 7210-1:2014 (230 ° C., 21 N load), and 0.9 g /10 minutes to 1.0 g/10 minutes is more preferable. If the MFRs of the first linear low-density polyethylene and the second linear low-density polyethylene are within the above preferable ranges, when the adhesive layer 20 is formed by extrusion molding or the like, the extrudability is relatively high. Since the adhesive layer 20 is stable and molding defects are suppressed, it becomes easy to stably mold into a film shape, and the occurrence of molding defects such as burrs in the adhesive layer 20 during molding is suppressed.

Preferably, the first linear low density polyethylene 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.

Preferably, the first linear low density polyethylene has a higher density than the second linear low density polyethylene. The density of the first linear low-density polyethylene is preferably 0.913 g/cm ³ to 0.940 g/cm ³ , more preferably 0.915 g/cm ³ to 0.930 g/cm ³ . The density of the second linear low-density polyethylene is preferably 0.905 g/cm ³ to 0.912 g/cm ³ , more preferably 0.908 g/cm ³ to 0.910 g/cm ³ .

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

The styrenic elastomer contained in the adhesive layer 20 can function, for example, as a compatibilizer. 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. However, if the styrene content is too high, the flexibility is impaired, so the styrene content in the styrene elastomer is preferably 10% by mass to 50% by mass, more preferably 12% by mass to 30% by mass, and 15% by mass. ~20% by mass is more preferred.

Specific examples of styrene-based elastomers include styrene-ethylene copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-ethylene-propylene-styrene block copolymers (SEPS), and 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 crystal block copolymer (SEBC), hydrogenated styrene-butadiene rubber (HSBR), and the like. Among these, one or more selected from SEBS, SEPS, SEBC, and HSBR are preferable, and SEBS is particularly preferable. In addition, SEBS is generally obtained by hydrogenating (hydrogenating) a styrene-butadiene-styrene block copolymer, and converting a butadiene unit into two ethylene units or a butylene unit. or those subjected to selective hydrogenation or the like.

Among the resin components constituting the adhesive layer 20, the ratio of the linear low-density polyethylene and the styrene-based elastomer is, for example, 80 parts by mass to 99 parts by mass of the linear low-density polyethylene with respect to 100 parts by mass of the resin component. It is preferable that the ratio is 1 part by mass to 20 parts by mass of the styrene-based elastomer.

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

In the adhesive layer 20, the total content of the linear low-density polyethylene and the 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 entire adhesive layer.

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

The polypropylene-based resin contained in the polypropylene-based resin layer 30 may be a propylene homopolymer, or a copolymer with at least one or more of ethylene or an α-olefin having 4 to 8 carbon atoms. good too. 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.

Moreover, the polypropylene-based resin may contain a thermoplastic elastomer, or may be composed only of a thermoplastic elastomer. The flexural modulus of the thermoplastic elastomer is preferably, for example, 240 MPa to 650 MPa.

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 to introduce short-chain branches, resulting in less long-chain branches and linear It has a similar molecular structure. α-Olefins to be copolymerized with linear low-density polyethylene include 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like.

Examples of the types of linear low-density polyethylene contained in the polypropylene-based resin layer 30 include resins polymerized using a Ziegler-Natta catalyst, resins polymerized using a single-site catalyst, and the like. A linear low-density polyethylene polymerized using a single-site catalyst is preferable because it has a narrow molecular weight distribution and excellent mechanical properties. Single site catalysts include metallocene catalysts. Examples of metallocene-based catalysts include catalysts containing metallocene compounds containing ligands having a cyclopentadienyl skeleton and metals such as zirconium and hafnium.

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

The bending elastic 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, even more preferably 360 MPa to 400 MPa. As long as the bending elastic modulus of the linear low-density polyethylene contained in the polypropylene-based resin layer 30 is within the preferred range described above, the polypropylene-based resin layer 30 can have appropriate flexibility.

MFR of linear low-density polyethylene is preferably 0.9 g/10 min to 1.25 g/10 min, and 1.1 g/10 min to 1.2 g/10 min is more preferred. If the MFR of the linear low-density polyethylene is within the above preferable range, when the polypropylene-based resin layer 30 is formed by extrusion molding or the like, the extrudability is relatively stable, and molding defects can be suppressed. It becomes easy to mold stably, and the occurrence of molding defects such as burrs in the polypropylene-based resin layer 30 during molding can be suppressed.

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

The density of linear low-density polyethylene is preferably 0.905 g/cm ³ to 0.912 g/cm ³ , more preferably 0.908 g/cm ³ to 0.910 g/cm ³ .

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 further preferably 20% by mass to 25% by mass. preferable. If the content of the linear low-density polyethylene is within the above preferable range, the polypropylene-based resin layer 30 has sufficient flexibility and exhibits the effect of reducing the risk of breakage when external force such as dropping is applied. be able to.

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

The materials constituting the layers constituting the laminate 1, that is, the cyclic olefin-based resin layer 10, the adhesive layer 20, the polypropylene-based resin layer 30, and the like, are required to improve the appearance of the container, stabilize the quality, and perform other required functions. In order to impart, it may contain various additives such as antioxidants, ultraviolet absorbers, antistatic agents, lubricants, antiblocking agents, etc., as long as they do not impair safety and hygiene.

The thickness of each layer of the cyclic olefin-based resin layer 10, the adhesive layer 20, and the polypropylene-based resin layer 30 is appropriately designed for the use of the container molded using the laminate 1, and the like. 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.

A method for molding each layer constituting the laminate 1 is not particularly limited, but a T-die molding method, an inflation molding method, or the like can be used. When using the T-die molding method, each layer constituting the laminate 1 may be made into a film (sheet) or the like after the T-die molding, and then rapidly cooled with a cooling roll. In the case of continuously molding the films of each layer constituting the laminate 1, it is preferable to roll up the long molded body such as the films of each layer constituting the laminate 1 after molding, because the productivity is excellent. .

The laminate 1 may be laminated with other layers such as a sealant layer and a base material, if necessary. That is, an adhesive layer or an anchor layer may be interposed between the layers, or the layers may be laminated so as to be in direct contact with each other. As other layers, one layer or multiple layers such as a reinforcing layer, a gas barrier layer, a light shielding layer, and a printing layer can be appropriately selected. The sealant layer is a layer used for heat sealing, and is arranged as the innermost layer in contact with the contents as a packaging material. Heat sealing is a method of bonding by melting a sealant layer, but the sealing method is not particularly limited, and includes hot plate sealing, ultrasonic sealing, high frequency sealing, impulse sealing, and the like. The substrate may be the other outermost surface of the laminate opposite to the sealant layer, or may be laminated inside the other outermost surface.

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

The method for manufacturing the laminate 1 according to the present embodiment is not particularly limited, and the laminate 1 is constructed by an extrusion lamination method, a dry lamination method, a co-extrusion method, or a combination of two or more of these methods. Each layer may be appropriately laminated. The thickness of the sealant layer is appropriately designed for the application of the container molded using the laminate 1, and is not particularly limited, but may be, for example, 5 μm to 150 μm, preferably 15 μm to 100 μm.

When 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 during the production of the laminate 1, an adhesive layer or an anchor layer is interposed between these three layers. layered together.

The laminate 1 has three layers of the cyclic olefin-based resin layer 10, the adhesive layer 20, and the polypropylene-based resin layer 30, but as described above, any of these layers may be provided in plurality. For example, the laminate 1 may include five layers in which a polypropylene-based resin layer 30, an adhesive layer 20, a cyclic olefin-based resin layer 10, an adhesive layer 20, and a polypropylene-based resin layer 30 are laminated in this order.

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 polypropylene resin layer 30 contains polypropylene resin and linear low-density polyethylene. , the interlayer adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20 is 25 N/15 mm or more. The linear low-density polyethylene contained in the polypropylene-based resin layer 30 can exhibit the effect of imparting flexibility to the polypropylene-based resin layer 30 more than the polypropylene-based resin, and the cyclic olefin-based resin layer 10 of the adhesive layer 20 A decrease in adhesive strength can be suppressed. Therefore, even when the adhesive layer 20 is sandwiched between the polypropylene resin layer 30 and the cyclic olefin resin layer 10, the adhesiveness to the cyclic olefin resin layer 10 can be improved. Adhesive strength between the layer 10 and the polypropylene resin layer 30 is enhanced. Therefore, the laminate 1 can have excellent interlayer adhesive strength between the cyclic olefin resin layer 10 and the polypropylene resin layer 30 .

Since 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, it can be effectively used as a container material for plastic containers. In addition, since the laminate 1 contains linear low-density polyethylene in the polypropylene-based resin layer 30, the heat resistance of the polypropylene-based resin layer 30 can be improved. Even if exposed (for example, for 20 minutes), the adhesion between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30 can be easily maintained. Therefore, the laminate 1 can maintain the interlayer adhesive strength required for use before and after sterilization even after sterilization, so it can be effectively used as a container material such as a drug solution bag that requires high-pressure steam sterilization.

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 enhanced, the flexibility of the laminate 1 as a whole can be enhanced. Therefore, the adhesive layer 20 can exhibit high adhesiveness to the cyclic olefin resin layer 10, so that the adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20 can be further enhanced. 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 .

Moreover, the laminated body 1 can have high heat resistance because the polypropylene resin layer 30 contains 10 mass % or more of linear low-density polyethylene. Since the laminate 1 can have heat resistance even at high temperatures exceeding 120° C., high-pressure steam sterilization can be performed, and even if high-pressure steam sterilization is performed, a decrease in interlayer adhesive strength can be suppressed. can.

In the laminate 1, the linear low-density polyethylene contained in the polypropylene-based resin layer 30 can have a flexural modulus of 300 MPa to 450 MPa. As a result, the polypropylene-based resin layer 30 can have appropriate flexibility, so that the laminate 1 reduces the risk of damage when an external force is applied from the outside due to dropping or the like, and the adhesive layer 20 and the polypropylene-based resin layer It is possible to make it easier to maintain the state of adhesion with 30 .

In the laminate 1, the polypropylene-based resin layer 30 can contain the polypropylene-based resin and the linear low-density polyethylene at a mass ratio of 90:10 to 60:40. As a result, the polypropylene resin layer 30 can further increase the adhesiveness to the cyclic olefin resin layer 10, so that the adhesive strength between the cyclic olefin resin layer 10 and the adhesive layer 20 can be reliably 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 .

The laminate 1 includes a first linear low-density polyethylene and a second linear low-density polyethylene as two types of linear low-density polyethylene in the adhesive layer 20, and the first linear low-density polyethylene contained in the adhesive layer 20. The flexural modulus of the low-density polyethylene can be 150 MPa to 250 MPa, and the flexural modulus of the second linear low-density polyethylene can be 50 MPa to 130 MPa. Thereby, the adhesion layer 20 can improve the flexibility and the adhesion to the cyclic olefin resin layer 10 . Therefore, the laminate 1 can reduce the risk of damage when an external force is applied from the outside due to dropping or the like, and can easily maintain the adhesion state between the adhesive layer 20 and the polypropylene resin layer 30. The adhesive force between the resin layer 10 and the adhesive layer 20 can be further enhanced.

In the laminate 1, the content of the first linear low-density polyethylene contained in the adhesive layer 20 is 20% to 65% by mass, and the content of the second linear low-density polyethylene is 30% to 70% by mass. %. As a result, the adhesive layer 20 can improve its flexibility and reliably enhance its adhesion to the cyclic olefin resin layer 10 . Therefore, the laminate 1 can reliably reduce the risk of damage when an external force is applied, and can stably maintain the adhesion state between the adhesive layer 20 and the polypropylene resin layer 30, and the cyclic olefin resin layer The adhesive strength between 10 and adhesive layer 20 can be reliably increased.

In the laminate 1, the adhesive layer 20 can contain a styrene-based elastomer. Thereby, the adhesive layer 20 can more reliably have flexibility. Therefore, the laminate 1 can easily maintain the state of adhesion between the cyclic olefin-based resin layer 10 and the polypropylene-based resin layer 30 .

As described above, since the laminate 1 has excellent interlayer adhesive strength, if it is used as a container material such as a plastic container, the durability of the plastic container can be improved, so it can be suitably used for the plastic container. .

<Plastic container>
Next, a plastic container formed using the laminate 1 according to this embodiment will be described. The plastic container has an accommodating portion for storing the contents, and the accommodating portion is formed by overlapping the cyclic olefin resin layers 10 of the laminate 1 so as to face each other, and joining and sealing the peripheral edges thereof. can be formed with

The plastic container can be used as a packaging bag (pouch), tube packaging, or the like. When a spout is provided in the packaging bag, the spout can be preferably 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 sealing performance. It is preferable to join the laminate 1 and the spout by heat sealing using a spout made of a resin that can be heat-sealed with the cyclic olefin resin layer 10 of the laminate 1 . When the laminate 1 and the spout are heat-sealed, the spout may be inserted between the laminates 1 stacked with the cyclic olefin resin layer 10 on the inside and heat-sealed, or a flange may be attached to one end of the spout. A portion or a boat-shaped fusion base may be provided, and the flange or fusion base may be heat-sealed with the cyclic olefin resin layer 10 on the periphery of the hole provided in the laminate 1 or the inner surface of the opening of the packaging bag.

Examples of contents include pharmaceuticals (drugs), food and drink, and cosmetics. The drug may be a substance that is highly adsorbable or permeable to general resins such as nitroglycerin, albumin, vitamins, trace elements, radical scavengers, or the pyrazolone derivative edaravone or a pharmaceutically acceptable salt thereof. It may be an aqueous solution containing. The pyrazolone derivative may have one or more substituents such as an alkyl group, an aromatic group, or a halogen atom on the carbon atom or nitrogen atom of the pyrazolone. The pyrazolone derivative may form salts with organic acids, inorganic acids and the like.

The form of the packaging bag is not particularly limited, and in addition to small bags such as three-sided bags, four-sided bags, gusseted bags, gusset bags, and self-supporting bags, large-sized bags such as inner bags for bag-in-box and inner bags for drums can be used. It can be applied to bags and the like. The packaging bag can be used, for example, as a drug solution bag containing an infusion solution or the like, a blow container, or the like.

FIG. 2 is a side view showing an example of a plastic container. As shown in FIG. 2, the plastic container 100 may have a container portion 110 for storing contents and a mouth portion 120 for discharging the contents. The accommodating portion 110 can be formed by arranging the laminates 1 so as to overlap each other so as to face each other.

As described above, the plastic container can have high durability by forming the storage portion from the laminate 1 according to the present embodiment. Therefore, the plastic container can suppress delamination even if the interlayer adhesion strength of the laminate forming the container portion gradually decreases during long-term storage of the contents in the container portion, so cracks in the container portion can be suppressed. It is possible to suppress the leakage of the contents due to the occurrence of such as. In addition, the plastic container can maintain a high interlayer adhesive strength of the laminate forming the container even after sterilization. Therefore, when the plastic container is used as, for example, a chemical solution bag, the chemical solution can be stored for a long period of time, so that a highly reliable chemical solution bag can be provided.

As described above, the embodiment has been described, but the above embodiment is presented as an example, and the present invention is not limited by the above embodiment. The above embodiments can be implemented in various other forms, and various combinations, omissions, replacements, changes, etc. can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

Hereinafter, the embodiment will be described more specifically by showing examples, but the embodiment is not limited to these examples. Examples 1 to 6 are examples.

<Preparation of pouch>
[Example 1]
A composition for forming a cyclic olefin resin layer, a composition for forming an adhesive layer, and a composition for forming a polypropylene resin layer, which are used to prepare each layer constituting a laminate, were prepared.

(Preparation of Composition for Forming Cyclic Olefin Resin Layer)
Cyclic olefin polymer 1 (ZEONOR (registered trademark), manufactured by Nippon Zeon Co., Ltd., density 1.02 g/cm ³ , glass transition temperature: 136°C) and cyclic olefin polymer 2 (ZEONEX (registered trademark), Nippon Zeon Co., Ltd. (manufactured by the company, density 1.02 g/cm ³ , glass transition temperature: 136° C.) were blended at a ratio of 70% by mass:30% by mass to prepare a composition for forming a cyclic olefin resin layer.

(Preparation of adhesive layer-forming composition)
LLDPE1 (Nipolon (registered trademark), 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 system polyethylene "Harmolex (registered trademark), manufactured by Japan Polyethylene Co., Ltd.", MFR: 0.9 g/10 min, density: 0.908 g/cm ³ , flexural modulus: 90 MPa, melting peak temperature: 120 ° C.) and phase 50% by mass: 40% by mass of a styrene-based elastomer (SEBS "Kraton (registered trademark), manufactured by Kraton Co., Ltd.", MFR: 22 g/10 min, styrene content: 12.3 to 14.3% by mass) as a solubilizing agent. : A composition for an adhesive layer was prepared by blending so as to be 10% by mass.

(Preparation of composition for forming polypropylene resin layer)
Polypropylene-based thermoplastic elastomer (ZELAS (registered trademark), 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%, melting peak 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 at a ratio of 75% by mass:25% by mass to prepare a composition for a polypropylene-based resin layer.

(Preparation of laminate)
Using a T-die multilayer film forming machine, the cyclic olefin resin layer-forming composition, the adhesive layer-forming composition, and the polypropylene resin layer composition are co-extruded to form a cyclic olefin resin layer, an adhesive layer, and polypropylene. A laminate was produced in which the system resin layers were laminated in this order. The thickness of each layer of the cyclic olefin resin layer, the adhesive layer and the polypropylene resin layer was 150 μm, 65 μm and 25 μm.

The composition of each layer of the cyclic olefin resin layer, the adhesive layer and the polypropylene resin layer constituting the laminate is a composition for forming a cyclic olefin resin layer, a composition for forming an adhesive layer and a composition for forming a polypropylene resin layer. corresponds to the respective composition of Table 1 shows the compositions of the cyclic olefin-based resin layer, the adhesive layer, and the polypropylene-based resin layer.

(Preparation of pouch)
Using the produced laminate, the innermost layers were superimposed, and the outer periphery of the laminate except for the filling port was heat-sealed to prepare an infusion bag-shaped pouch with outer dimensions of 172 mm×115 mm. After trimming so that the peripheral seal width was 5 mm, the inside of the pouch was filled with 105 mL of water, and then the filling port was heat-sealed to seal the pouch.

[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. Table 1 shows the compositions of the cyclic olefin-based resin layer, the adhesive layer, and the polypropylene-based resin layer.

<Evaluation of laminate>
[Before sterilization]
The interlayer adhesion strength and transparency of the laminate were measured before the sterilization treatment of the produced pouch.

(Interlayer adhesive strength)
The interlayer adhesive strength between the cyclic olefin resin layer and the polypropylene resin layer was measured by the following procedure. First, 5 pieces of 15 mm width×150 mm length were cut out from the non-heat-sealed sheet of the pouch, and ethyl acetate was used to separate a portion between the layers from one end of the sheet. It was developed until the length of the separation between the layers became 20 mm or more, and both ends where the layers were separated were attached to grips of a tensile tester. Next, a tensile load was applied at a tensile speed of 5 mm/min to delaminate a length of 30 mm, and the average load (unit: N/15 mm) was measured. The average load (unit: N/15 mm) of the cut five sheets was taken as the interlaminar adhesive strength between the cyclic olefin resin layer and the polypropylene resin layer. With reference to the results of packaging products, if the interlayer adhesion strength is 25 N / 15 mm or more, the interlayer adhesion strength is evaluated as "good", and if the average interlayer adhesion strength is less than 25 N / 15 mm Adhesion strength was evaluated as "poor".

(transparency)
Transparency was evaluated by the following procedure. According to the transparency test method 1 described in the 7.02 plastic drug container test method of the 17th revision of the Japanese Pharmacopoeia (JP17), a sample of the laminate is measured from the pouch to a size of 0.9 cm × 4 cm. Individual pieces were cut out and immersed in a cell for ultraviolet absorption spectrum measurement filled with water. Using a cell filled only with water as a control, the light transmittance at a wavelength of 450 nm was measured and recorded with an ultraviolet-visible spectrophotometer. Considering that the light transmittance must be 55% or more according to the standard for plastic containers for aqueous injections in the same pharmacopoeia, the average value of the measured light transmittance of 5 samples is 65% or more. Transparency was rated as "good" in some cases, and as "poor" when the average light transmittance measurements were less than 65%.

[After sterilization]
The sealed pouch was placed in an autoclave and sterilized at 121° C. for 20 minutes. After the sterilization, the pouch was taken out from the autoclave, the temperature of the pouch was rapidly lowered with cooling water, and the interlayer adhesion strength and transparency of the laminate after the sterilization were measured in the same manner as described above.

Table 1 shows the measurement results of the interlayer adhesive strength and transparency of the laminate used to manufacture the pouch of each example.

From Table 1, in Examples 1 to 5, the interlayer adhesion strength of the laminates before and after sterilization was greatly increased, the decrease in transparency was suppressed before and after sterilization, and the standards for plastic containers for aqueous injections were satisfied. 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 usage conditions. Moreover, the decrease in transparency was suppressed before and after sterilization, and it satisfied the standards for plastic containers for aqueous injections.

Therefore, in the laminates of Examples 1 to 6, the polypropylene resin layer contains a polypropylene resin and LLDPE, and the interlayer adhesion strength between the cyclic olefin resin layer and the adhesive layer can be 25 N/15 mm or more, and excellent interlayer adhesion can have strength. Therefore, it can be said that the laminates of Examples 1 to 6 can improve durability when applied to plastic containers. When a plastic container is used as a chemical solution bag, if the laminate constituting the chemical solution bag has high interlaminar adhesive strength even after sterilization, even if the interlaminar adhesive strength gradually decreases during long-term storage of the chemical solution in the chemical solution bag. It is preferable because it can suppress interlayer separation (delamination) and maintain the function as a chemical solution bag. Therefore, it can be said that the drug solution bags formed using the laminates of Examples 1 to 6 can store the drug solution for a long period of time.

REFERENCE SIGNS LIST 1 laminate 10 cyclic olefin resin layer 20 adhesive layer 30 polypropylene resin layer 100 plastic container

Claims (10)

A cyclic olefin resin layer, an adhesive layer and a polypropylene resin layer are laminated in this order,
The polypropylene-based resin layer contains a polypropylene-based resin and linear low-density polyethylene,
A laminate in which the interlayer adhesive strength between the cyclic olefin resin layer and the adhesive layer is 25 N/15 mm or more. 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. 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. 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. The adhesive layer contains two types of linear low-density polyethylene,
One linear low-density polyethylene contained in the adhesive layer has a flexural modulus of 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. The content of one 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. The laminate according to any one of claims 1 to 6, wherein the adhesive layer contains a styrene-based elastomer. A container for storing contents, in which the laminate according to any one of claims 1 to 7 is arranged so as to be superimposed so as to face each other;
a mouth for discharging the contents;
A plastic container with 9. The plastic container according to claim 8, wherein said contents are pharmaceuticals. 10. The plastic container according to claim 8 or 9, wherein the plastic container is an infusion bag or a blow container.

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