HK1259016B - Barrier mouth stopper and container with barrier mouth stopper - Google Patents

Description

Barrier plug and container with barrier plug

Technical Field

The present invention relates to a barrier plug and a container with the barrier plug.

Background Art

In the past, various forms of plastic flexible packaging bags have been developed and sold, containing a variety of foods and beverages, such as baby food, liquid food, infusion bags, juices, jelly drinks, nutritional beverages, drinking water, tea, coffee drinks, milk, seasonings, oils, cosmetics, and others. In recent years, for the convenience of these various forms of plastic flexible packaging bags, including self-supporting bags and gusset bags, packaging products with a spout installed at one side of the bag body have been proposed. These packaging products, known as spout bags ("spauto pouches" in Japanese), are easy to handle and offer resealability, leading to increasing demand.

However, since the contents are often degraded by oxygen, moisture, etc., it is common to use laminated materials as films constituting such bags and containers, which improve the gas barrier properties against oxygen and water vapor by laminating aluminum foil and forming a barrier layer by coating (evaporation) of silicon oxide, diamond-like carbon, etc.

On the other hand, some containers for storing medications, such as infusion bags, are also equipped with stoppers. While bags and containers using packaging materials (films) with such barrier layers can improve overall barrier properties, the stoppers provided on these bags and containers lack measures to enhance gas barrier properties. Consequently, the stoppers significantly affect the permeation of gases into the bulk of the contents, significantly hindering degradation of the contents. To address this issue, numerous measures have been proposed to suppress degradation caused by gas permeation and improve shelf life (see, for example, Patent Documents 1-3).

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-162272

Patent Document 2: Japanese Patent Application Laid-Open No. 2009-292492

Patent Document 3: Japanese Patent Application Laid-Open No. 2006-1623

Summary of the Invention

Problems to be solved by the invention

However, conventional cylindrical molded articles such as stoppers have problems such as reduced oxygen barrier properties when stored under high humidity, reduced water vapor barrier properties, and reduced oxygen barrier properties when subjected to hot water treatments such as boiling or retorting.

To address the issue of reduced oxygen barrier properties at high humidity, one approach is to roll a highly humidity-resistant vapor-deposited film onto the cylindrical portion of the stopper and perform injection molding. However, this approach introduces new problems: gas intrusion through the adhesive layer and the flap seal during winding, as well as cracking in the vapor-deposited layer during winding. Furthermore, there is the issue of odor permeation and leakage of the contents.

The present invention has been made in view of the above-mentioned problems, and its object is to provide a barrier stopper having excellent storage properties at room temperature and at high temperature and high humidity, and excellent aroma preservation properties for odorous substances, and a container with a barrier stopper provided with the barrier stopper.

"Room temperature storage stability": For example, when stored for 3 days at 23°C and 50% RH, there is little deterioration of the contents.

"Storability under high temperature and high humidity": For example, when stored for 3 days under the conditions of 40°C and 90% RH, there is little deterioration of the contents.

Means for solving problems

The inventors of the present application conducted intensive research to solve the above-mentioned problems and found that the above-mentioned problems can be solved by using a tubular barrier material having a good balance between oxygen transmission rate and water vapor transmission rate, thereby completing the present invention.

That is, the present invention is as follows.

[1]

The barrier plug comprises a mouth body that can be mounted on a container and a cylindrical molded body that is inserted into the mouth body.

The cylindrical molded body has a resin layer containing a barrier resin,

The oxygen transmission rate of the resin layer is 10000 mL·μm/m ² ·24 hrs·MPa (23°C·65%RH) or less, and

The water vapor transmission rate of the resin layer is 1000 g·μm/m ² ·24 hrs (38°C·90%RH) or less.

The cylindrical molded body forms a discharge flow path for discharging the contents in the container to the outside.

[2]

The barrier port plug according to [1], wherein the mouth body contains a polyolefin resin.

〔3〕

The barrier port plug according to [1] or [2], wherein the melting point of the barrier resin is higher than the melting point of the polyolefin resin.

[4]

The barrier port plug according to any one of [1] to [3], wherein the mouth body has a coating layer, the coating layer covering at least a portion of the end surface of the end of the cylindrical molded body opposite to the end that can be mounted on the container,

The covering layer covers the end surface of the resin layer containing the barrier resin.

〔5〕

The barrier port plug according to any one of [1] to [4], wherein the barrier resin comprises a vinylidene chloride copolymer.

[6]

The barrier port plug according to any one of [1] to [5], wherein the cylindrical molded body comprises an inner layer and an outer layer,

The inner layer contains a polyolefin resin,

The outer layer is the resin layer.

[7]

The barrier plug according to any one of [1] to [5], wherein the cylindrical molded body comprises an inner layer, one or more intermediate layers, and an outer layer.

The inner layer contains a polyolefin resin,

The outer layer and/or the middle layer is the resin layer.

〔8〕

A container with a barrier plug, comprising a container and a barrier plug according to any one of [1] to [7] mounted on the container, wherein:

The container is composed of at least one selected from the group consisting of a laminate film having a resin layer (which contains a barrier resin), a laminate film having an aluminum foil layer, and a metal-deposited film, wherein the resin layer has an oxygen permeability of not more than 10,000 mL·μm/m ² ·24 hrs·MPa (23°C·65% RH) and a water vapor permeability of not more than 1,000 g·μm/m ² ·24 hrs (38°C·90% RH).

Effects of the Invention

According to the present invention, there can be provided a barrier stopper having excellent water vapor barrier properties and oxygen barrier properties and excellent aroma retention properties for odorous substances, and a container with a barrier stopper provided with the barrier stopper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a specific example of a barrier stopper according to the present embodiment and a container with a barrier stopper provided with the barrier stopper.

FIG. 2 is a schematic diagram showing one method of manufacturing the barrier plug according to the present embodiment.

[Fig. 3] is a schematic cross-sectional view showing the barrier plug of this embodiment.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described in detail, but the present invention is not limited thereto and various modifications can be made without departing from the spirit and scope of the present invention.

〔Blocking plug〕

The barrier plug of this embodiment has a mouth body that can be installed on a container, and a cylindrical molded body inserted into the mouth body. The cylindrical molded body has a resin layer containing a barrier resin, and the oxygen permeability of the resin layer is less than 10000 mL·μm/ ^m2 ·24hrs·MPa (23℃·65%RH), and the water vapor permeability of the resin layer is less than 1000g·μm/ ^m2 ·24hrs (38℃·90%RH). The cylindrical molded body forms a discharge flow path for discharging the contents in the container to the outside.

FIG1 is a schematic diagram showing a specific example of a barrier stopper according to the present embodiment and a container equipped with the barrier stopper. The barrier stopper according to the present embodiment can be used for containers for storing food, etc., and can also be used as a stopper for containers requiring water vapor barrier properties and oxygen barrier properties in addition to food.

"Containers for storing food, etc." are not particularly limited, but include, for example, spouted bags such as Cheer Pack (registered trademark), which contain beverages, jellies, soy sauce, and other condiments; bags with spouts such as bag-in-box bags and infusion bags; and bottles with spouts. Conventional spouts have poor oxygen and/or water vapor barrier properties. Therefore, even if the container for storing food, etc., possesses these properties, there are still problems with oxygen and water vapor permeating through the spout, degrading the packaged items or, conversely, emitting components of the packaged contents through the spout. Furthermore, during the food packaging process, for sterilization purposes, the food to be packaged is sealed in a heated container, or the container containing the food is heated. However, if the spout is exposed to water vapor generated by the food during the packaging process, the barrier properties are further reduced.

In contrast, the barrier cap of this embodiment, by providing a predetermined cylindrical molded body, can prevent the degradation of food, beverages, and pharmaceuticals within packages that require protection from gases such as oxygen and water vapor, thereby enabling long-term storage while maintaining hygiene and safety. In particular, the barrier cap of this embodiment maintains its barrier properties even after hot water treatments such as boiling or retorting.

Mouth

The resin constituting the main body of the nozzle is not particularly limited, and examples thereof include polyethylene resins such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ethylene-α-olefin (hereinafter also referred to as "PE"); polypropylene resins such as homopolymers or random copolymers, block copolymers, etc. (hereinafter also referred to as "PP"); ethylene-vinyl acetate copolymers (hereinafter referred to as EVA); polyamide resins (hereinafter also referred to as "PA"); and adhesive resins. Among them, polyethylene resins, polypropylene resins, and polyolefin resins such as ethylene-vinyl acetate copolymers are preferred. By using polyolefin resins, there is a tendency for the moldability to be further improved. It should be noted that the resin constituting the main body of the nozzle may be used alone or in combination of two or more.

[Tubular molded body]

The cylindrical molded body is inserted into the nozzle body, and the inserted cylindrical molded body forms a discharge flow path for discharging the contents of the container to the outside. The cylindrical molded body has a resin layer containing a barrier resin, and the oxygen permeability of the resin layer is 10,000 mL·μm/m ² ·24hrs·MPa (23°C·65% RH) or less, and the water vapor permeability of the resin layer is 1,000 g·μm/m ² ·24hrs (38°C·90% RH) or less. It should be noted that "RH" means relative humidity. In addition, the so-called "cylindrical molded body" is not particularly limited as long as it is a molded body formed into a cylindrical shape and has a resin layer containing a barrier resin.

〔Resin layer〕

The oxygen permeability of the resin layer at 23°C and 65% RH is preferably 10,000 mL·μm/m ² ·24 hrs·MPa or less, more preferably 800 mL·μm/m ² ·24 hrs·MPa or less, even more preferably 500 mL·μm/m ² ·24 hrs·MPa or less, even more preferably 450 mL·μm/m ² ·24 hrs·MPa or less, still more preferably 350 mL·μm/m ² ·24 hrs·MPa or less, particularly preferably 300 mL·μm/m ² ·24 hrs·MPa or less, and most preferably 250 mL·μm/m ² ·24 hrs·MPa or less. The lower limit of the oxygen permeability of the resin layer at 23°C and 65% RH is not particularly limited, but is 0 mL·μm/m ² ·24 hrs·MPa. It should be noted that "RH" in this specification means relative humidity.

By setting the oxygen permeability of the resin layer at 23°C and 65% RH to 10,000 mL·μm/m ² ·24hrs·MPa or less, there is a tendency to suppress the deterioration of the contents and further improve the freshness retention. It should be noted that the oxygen permeability of the resin layer at 23°C and 65% RH can be reduced by selecting a resin layer with better barrier properties. Specifically, by using a vinylidene chloride copolymer, the oxygen permeability can be more advantageously reduced, but the invention is not limited to this. In addition, the oxygen permeability of the resin layer at 23°C and 65% RH can be measured using the method described in the Examples. Here, the so-called "resin with barrier properties" is not particularly limited, and examples thereof include ethylene-vinyl alcohol copolymers, polyamide resins, polychlorotrifluoroethylene resins, and polyacrylonitrile resins.

The water vapor transmission rate of the resin layer at 38°C and 90% RH is preferably 1000 g·μm/m ² ·24 hrs or less, more preferably 500 g·μm/m ² ·24 hrs·MPa or less, further preferably 300 g·μm/m ² ·24 hrs·MPa or less, even more preferably 200 g·μm/m ² ·24 hrs·MPa or less, still more preferably 100 g·μm/m ² ·24 hrs·MPa or less, particularly preferably 50 g·μm/m ² ·24 hrs·MPa or less, and most preferably 25 g·μm/m ² ·24 hrs·MPa or less. The lower limit of the water vapor transmission rate of the resin layer at 38°C and 90% RH is not particularly limited, but is 0 g·μm/m ² ·24 hrs·MPa.

By setting the water vapor permeability of the resin layer at 38°C and 90% RH to 1000 g·μm/ ^m² ·24 hrs·MPa or less, there is a tendency to suppress deterioration of the contents and further improve freshness retention. It should be noted that the water vapor permeability of the resin layer at 38°C and 90% RH can be reduced by selecting a resin layer with superior barrier properties. Specifically, the use of a vinylidene chloride copolymer can achieve a more advantageous reduction in water vapor permeability, but the present invention is not limited to this. The water vapor permeability of the resin layer at 38°C and 90% RH can be measured using the method described in the Examples.

The oxygen permeability reduction rate is evaluated by dividing the oxygen permeability of the resin layer at 23°C and 65% RH by the oxygen permeability at a high humidity of 90% RH at 23°C, and multiplying the result by 100. A value indicating no deterioration of oxygen barrier properties due to humidity is considered 100%. This oxygen permeability reduction rate is preferably 80-100%, more preferably 90-100%, and even more preferably 95-100%. During the packaging process, for sterilization purposes, procedures such as sealing the packaged contents in a heated state or heating the container containing the food are often performed. By keeping the oxygen permeability reduction rate within the above range, even in such situations, a decrease in barrier properties such as oxygen permeability can be further suppressed. It should be noted that the oxygen permeability reduction rate can be controlled by the choice of resin. Specifically, the use of a vinylidene chloride copolymer can significantly reduce the water vapor permeability rate.

The thickness of the resin layer is preferably 5 to 1500 μm, more preferably 10 to 1000 μm, further preferably 25 to 700 μm, and particularly preferably 50 to 500 μm. By setting the thickness of the resin layer within the above range, the cylindrical molded body can be used for a wider range of applications.

The thickness of the cylindrical molded body is preferably 5 to 1500 μm, more preferably 50 to 1000 μm, further preferably 75 to 700 μm, and particularly preferably 100 to 600 μm. By setting the thickness of the cylindrical molded body within the above range, the cylindrical molded body can be used for a wider range of applications.

The inner diameter of the cylindrical molded body can be adjusted appropriately depending on its intended use, and is not particularly limited. The diameter is 1 to 100 mm, or even 100 mm or greater for large containers. For example, in the case of bags and containers with barrier plugs, which are characterized by being sealed with a barrier plug, the inner diameter of the cylindrical molded body is preferably 5 to 15 mm, and the thickness of the cylindrical molded body is preferably 0.3 to 2 mm. The barrier plug can be manufactured by insert molding the cylindrical molded body into the main body, for example.

(Barrier resin)

The resin layer contains a barrier resin, and the resin layer is preferably formed of a barrier resin. The barrier resin is not particularly limited, and examples thereof include vinylidene chloride copolymers, vinylidene chloride homopolymers, ethylene-vinyl alcohol copolymers, polyamide resins, polychlorotrifluoroethylene resins, and polyacrylonitrile resins. By using such a barrier resin, there is a tendency for water vapor impermeability and oxygen impermeability to be further improved. Among them, it is preferred to contain a vinylidene chloride copolymer as the barrier resin, and the barrier resin is preferably formed of a vinylidene chloride copolymer. Vinylidene chloride copolymers have the following advantages: excellent water vapor impermeability; and, it is not easy for oxygen impermeability to decrease due to moisture absorption. In addition, the tubular molded body of this embodiment may also have a first resin layer containing a barrier resin, and a second resin layer containing a barrier resin with a composition different from that of the first resin layer. It should be noted that the barrier resins may be used alone or in combination of two or more.

The melting point of the barrier resin is preferably higher than that of the resin constituting the nozzle body. This prevents deformation of the cylindrical molded body due to the heat of the molten resin during injection molding of the resin constituting the nozzle body by melting the resin constituting the nozzle body around the outer periphery of the cylindrical molded body in the manufacturing method of the barrier plug described below.

(vinylidene chloride copolymer)

A vinylidene chloride copolymer refers to a copolymer formed by a vinylidene chloride monomer and a monomer copolymerizable therewith. Monomers copolymerizable with vinylidene chloride monomers are not particularly limited, and examples thereof include vinyl chloride; acrylic acid esters such as methyl acrylate and butyl acrylate; acrylic acid; methacrylic acid esters such as methyl methacrylate and butyl methacrylate; methacrylic acid; methacrylonitrile; and vinyl acetate. Among these, methyl acrylate and methacrylonitrile are preferred from the perspective of achieving a balance between water vapor and oxygen impermeability and extrusion processability. These copolymerizable monomers may be used alone or in combination of two or more.

The comonomer content of the vinylidene chloride-acrylate copolymer, the vinylidene chloride-methacrylate copolymer, and the vinylidene chloride-methacrylonitrile copolymer is preferably 1 to 35% by mass, more preferably 1 to 25% by mass, even more preferably 2 to 15.5% by mass, even more preferably 2 to 10% by mass, even more preferably 4 to 10% by mass, and particularly preferably 5 to 8% by mass. When the comonomer content of the vinylidene chloride copolymer is 1% by mass or more, there is a tendency for the melt properties during extrusion to be further improved. Furthermore, when the comonomer content of the vinylidene chloride copolymer is 35% by mass or less, there is a tendency for the water vapor impermeability and oxygen impermeability to be further improved.

In addition, the comonomer (vinyl chloride) content of the vinylidene chloride-vinyl chloride copolymer is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, further preferably 1 to 21% by mass, further preferably 3.5 to 18.5% by mass, further more preferably 6 to 16% by mass, and particularly preferably 8.5 to 13.5% by mass. By making the comonomer content of the vinylidene chloride copolymer 1% by mass or more, there is a trend of further improving the melting characteristics during extrusion. In addition, by making the comonomer content of the vinylidene chloride copolymer 40% by mass or less, there is a trend of further improving water vapor impermeability and oxygen impermeability.

The weight average molecular weight (Mw) of the vinylidene chloride copolymer is preferably 50,000 to 150,000, more preferably 60,000 to 130,000, and further preferably 70,000 to 100,000. By making the weight average molecular weight (Mw) 50,000 or more, there is a trend that the melt tension required for molding is further improved. In addition, by making the weight average molecular weight (Mw) 150,000 or less, there is a trend that melt extrusion with maintained thermal stability becomes possible. It should be noted that, in the present embodiment, the weight average molecular weight (Mw) can be obtained by gel permeation chromatography (GPC method) using a standard polystyrene calibration curve.

(Polyolefin resin)

The polyolefin-based resin is not particularly limited, and examples thereof include polyethylene, polypropylene, ethylene-α-olefin copolymers, and ethylene-vinyl acetate copolymers.

The polyethylene is not particularly limited, and examples thereof include low-density polyethylene having a density of 0.910 to 0.930 g/cm ³ and high-density polyethylene having a density of 0.942 g/cm ³ or higher. The polypropylene is not particularly limited, and examples thereof include homopolypropylene and random polypropylene.

The comonomer (vinyl alcohol) content of the ethylene-vinyl alcohol copolymer is preferably 35 to 60 mol%, more preferably 38 to 58 mol%, even more preferably 38 to 54 mol%, even more preferably 39 to 49 mol%, and particularly preferably 41.5 to 46.5 mol%. When the comonomer content is within this range, oxygen permeability tends to be further improved. Furthermore, the saponification degree of the ethylene-vinyl alcohol copolymer is preferably 98 to 100 mol%, more preferably 99 to 100 mol%. When the saponification degree is within this range, oxygen permeability tends to be further improved.

The vinyl acetate content in the ethylene-vinyl acetate copolymer is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, even more preferably 10 to 25% by mass, and particularly preferably 15 to 20% by mass, relative to 100% by mass of the ethylene-vinyl acetate copolymer. When the vinyl acetate content is within this range, the interlayer adhesive strength tends to be further improved in a multilayer structure.

The content of vinyl alcohol in the ethylene-vinyl alcohol copolymer (polyvinyl alcohol) is preferably 25 to 60% by mass, more preferably 30 to 55% by mass, further preferably 35 to 50% by mass, and particularly preferably 40 to 45% by mass relative to 100% by mass of the ethylene-vinyl alcohol copolymer. When the content of vinyl alcohol is within this range, the oxygen permeability reduction rate tends to be further reduced.

(Polyamide resin)

The polyamide resin is not particularly limited, and examples thereof include polycaprolactam (nylon 6), polydodecanoamide (nylon 12), polybutylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyundecanediamine (nylon 116), polymethylene adipamide (nylon MXD6), polyp-phenylene adipamide (nylon PXD6), polybutylene sebacate (nylon 410), polybutylene adipamide (nylon 410), polybutylene adipamide (nylon 410), polybutylene adipamide (nylon 410), polybutylene adipamide (nylon 410), polybutylene adipamide (nylon 410), polybutylene adipamide (nylon 410), polymethylene ... ), polyhexamethylenediamine sebacamide (nylon 610), polydecanediamine sebacamide (nylon 106), polydecanediamine sebacamide (nylon 1010), polyhexamethylenediamine dodecanoyl (nylon 612), polydecanediamine dodecanoyl (nylon 1012), polyhexamethylenediamine isophthalamide (nylon 6I), polybutylene terephthalamide (nylon 4T), polypentamethylene terephthalamide (nylon 5T), poly-2-(1,2-diamino)-1,2-diamino ... -Methylpentanediamine (nylon M-5T), polyhexamethylenehexahydroterephthalic (nylon 6T (H)), polynonane terephthalamide (nylon 9T), polydecane terephthalamide (nylon 10T), polyundecanediamine (nylon 11T), polydodecane terephthalamide (nylon 12T), polybis(3-methyl-4-aminohexyl)methane terephthalamide (nylon PACMT), polybis(3-methyl-4-aminohexyl)methane isophthalamide (nylon PACMI), polybis(3-methyl-4-aminohexyl)methane dodecanoyl (nylon PACM12), polybis(3-methyl-4-aminohexyl)methane tetradecanoyl (nylon PACM14), etc. Among them, partially aromatic polyamides such as poly(m-xylylene adipamide) (nylon MXD6) are preferred from the viewpoint of oxygen barrier properties.

(Other additives)

The resin layer may contain other additives such as known plasticizers, heat stabilizers, colorants, organic lubricants, inorganic lubricants, surfactants, and processing aids as needed.

The plasticizer is not particularly limited, and examples thereof include acetyl tributyl citrate, acetylated monoglyceride, and dibutyl sebacate.

The heat stabilizer is not particularly limited, and examples thereof include epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, epoxy resins, magnesium oxide, and hydrotalcite.

[Layer structure]

The cylindrical molded article may have a single-layer structure comprising a resin layer containing a barrier resin. Depending on the intended use, it may also have a two-layer structure comprising an inner layer and an outer layer, or a three-layer structure comprising an inner layer, one or more intermediate layers, and an outer layer. In the case of a two-layer structure, the inner layer preferably comprises a polyolefin-based resin, and the outer layer is the aforementioned resin layer. In the case of a three-layer structure, the inner layer preferably comprises a polyolefin-based resin, and the outer layer and/or the intermediate layer are the aforementioned resin layers. This configuration facilitates attachment to bags and containers.

The resins constituting layers other than the resin layer containing the barrier resin are not particularly limited. Examples include polyethylene resins (hereinafter referred to as "PE") such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ethylene-α-olefin; polypropylene resins (hereinafter referred to as "PP") such as homopolymers, random copolymers, and block copolymers; ethylene-vinyl acetate copolymers (hereinafter referred to as "EVA"); polyamide resins (hereinafter referred to as "PA"); and adhesive resins. Furthermore, layers other than the resin layer containing the barrier resin may contain other components such as adhesives.

The layer structure of the cylindrical molded body having a structure of two or more layers is not particularly limited, and examples thereof include PE/PVDC/PE, PE/PVDC, PVDC/PE, PP/PVDC/PP, PP/PVDC, PVDC/PP, PE/EVA/PVDC/EVA/PVDC, PVDC/EVA/PE, PE/EVA/PVDC, PVDC/EVA/PE, PP/adhesive resin/PVDC/adhesive resin/PP, PP/adhesive resin/PVDC, PVDC/adhesive resin/PP, PE/EVA/PVDC/EVA/PE, PE/adhesive resin/PVDC, PE/adhesive resin/PVDC/adhesive resin/PE, etc. It should be noted that the expression "PE/PVDC" means that a PE layer and a PVDC layer are laminated from the inside to the outside of the cylindrical molded body.

〔Cover part〕

The barrier plug may include a cap covering the mouth of the plug. The portion of the cap covering the mouth of the plug is preferably made of a barrier resin, and the rest of the cap may contain a barrier resin or the same resin as exemplified for the nozzle body.

[Method for producing cylindrical molded article]

The cylindrical molded body of the present embodiment can be manufactured by molding methods such as extrusion molding, injection molding or blow molding. Wherein, preferably, the extrusion molding that makes resin melt and carries out extrusion molding or the injection molding that molten resin is injected into the mold and carries out molding. When using cylindrical molded body to process by injection molding, bag making, component installation processing etc., from the consideration of the good aspect of installation ease and dimensional accuracy such as joining, sealing, preferably, by extrusion molding, single layer or 2 or more layers are carried out multilayer extrusion molding and made cylindrical.

The cylindrical molded body thus extruded is cut into a specified length for use. For example, when used in a packaging container with a spout such as a bag with a mouth, such as CheerPack (registered trademark), the cylindrical molded body of this embodiment is molded into a barrier mouth plug by insert injection molding or the like, and then installed in the bag or container. In this case, the cylindrical molded body is used with a length that reaches the interior of the bag or container. In addition, when used in an infusion bag, the barrier mouth plug formed by insert injection molding or the tubular cylindrical molded body is sandwiched between the inner surface of the bag at the end or corner of the bag and heat-sealed or the like for installation.

[Method for manufacturing a barrier plug]

As shown in FIG1 , the barrier stopper 1 of this embodiment comprises a nozzle body 3 that can be mounted on a container 2 with a barrier stopper, and the aforementioned cylindrical molded body 4 inserted into the nozzle body. The cylindrical molded body forms a discharge passage 5 for discharging the contents of the container to the outside. The barrier stopper 1 is not particularly limited and can be manufactured, for example, by injection molding a resin constituting the nozzle body 3 around the cylindrical molded body 4.

The following description will be given using injection molding as an example. FIG2 shows a simplified diagram of one method of manufacturing a blocking plug according to the present embodiment. FIG2(a) shows a core mold 11 used in injection molding, on which a cylindrical cylindrical molded body mounting portion 13 is formed on the base 12 of the core mold 11. The cylindrical molded body mounting portion 13 is composed of a large diameter portion 13a, a small diameter portion 13b, and a coating portion 13c. The large diameter portion 13a is located on the base end side of the base 12 side of the cylindrical molded body mounting portion 13, the small diameter portion 13b is located on the front end side of the cylindrical molded body mounting portion 13, and the coating portion 13c is formed between the large diameter portion 13a and the small diameter portion 13b. The coating portion 13c is formed in a stepped shape toward the front end side of the cylindrical molded body mounting portion 13.

In this embodiment, the difference between the radii of the large-diameter portion 13a and the small-diameter portion 13b is approximately equal to the wall thickness of the cylindrical molded body 4. The outer diameter of the large-diameter portion 13a is approximately equal to the outer diameter of the cylindrical molded body 4, and the outer diameter of the small-diameter portion 13b is formed to be slightly smaller than the inner diameter of the cylindrical molded body 4. Specifically, it is formed to be 0.01 to 0.2 mm smaller than the inner diameter of the cylindrical molded body 4. The axial length of the small-diameter portion 13b of the cylindrical molded body mounting portion 13 is formed to be longer than the axial length of the cylindrical molded body 4.

FIG2(b) shows a molding die 14. The molding die 14 is formed by a left molding die and a right molding die, thereby being divisible left and right. A cavity 15 is formed within the molding die 14, and the inner peripheral surface of the molding die 14 is formed to have the same shape as the outer peripheral shape of the nozzle body. A gate is provided in the right molding die, facing the cavity 15, and is connected to the injection port (not shown) of the injection molding machine. The mold core 11 is configured to be movable forward and backward, thereby allowing the cylindrical molding body mounting portion 13 to be moved in and out of the cavity 15 of the molding die 14 in the vertical direction.

The blocking plug 1 is molded using an injection molding device having an injection molding machine and a molding die. As shown in FIG2(c), the cylindrical molded body 4 is mounted on the cylindrical molded body mounting portion 13 of the mold core 11 and inserted until one end of the cylindrical molded body 4 abuts against the root of the coating layer 13c. Therefore, the coating layer 13c serves as a positioning member for the cylindrical molded body 4. Then, as shown in FIG2(c), with the cylindrical molded body 4 already inserted into the cylindrical molded body mounting portion 13, the cylindrical molded body mounting portion 13 is inserted into the mold cavity 15 of the molding die 14, and the left molding die and the right molding die are closed.

Next, as shown in FIG2(c), a resin that has been stirred and melted using an injection molding machine is injected from the gate into the mold cavity 15. The cylindrical molded body 4 is subjected to the flow pressure of the molten resin and bears a load that attempts to move toward the large-diameter portion 13a at the base end of the cylindrical molded body mounting portion 13. However, this movement is restricted by the coating 13c of the cylindrical molded body mounting portion 13. Furthermore, since the coating 13c restricts the position of the cylindrical molded body 4, the coating 13c is formed on the cylindrical molded body mounting portion 13 so that the cylindrical molded body 4 is positioned correctly in the nozzle body.

Using an injection molding machine, molten resin is filled between the molding die 14 and the cylindrical molded body mounting portion 13 of the core 11, thereby forming the nozzle body. A stepped gap is formed between one end of the cylindrical molded body 4 and the coating layer portion 13c formed on the cylindrical molded body mounting portion 13. By filling this gap with molten resin, the nozzle body's coating layer 6 (see Figure 3) is formed. The coating layer 6 is formed as follows: the portion that contacts the end face of one end of the cylindrical molded body 4 becomes the limiting surface, and the surface of the coating layer 6 that contacts the coating layer portion 13c of the cylindrical molded body mounting portion 13 becomes the coating layer. At the other end of the cylindrical molded body 4, its end face is coated with molten resin, forming a retaining surface. In this way, the end faces of one end and the other end of the cylindrical molded body 4 are coated with the nozzle body. During molding, the nozzle body contacts the cylindrical molded body 4 in a molten state, thereby improving the tightness and adhesion between the nozzle body and the cylindrical molded body 4.

By cooling and solidifying the molten resin 16, the nozzle body 3 is formed to obtain the blocking port plug 1. Even if there is a slight gap between the cylindrical molded body 4 and the small diameter portion 13b of the cylindrical molded body mounting portion 13, the molten resin can be prevented from entering the gap by adjusting the viscosity of the resin.

In addition, from the viewpoint of water vapor barrier properties, oxygen barrier properties, and aroma retention, it is preferred that, when the barrier stopper 1 is installed in the container 2, the container 2 and the cylindrical molded body 4 overlap (lap) in the longitudinal direction of the cylindrical molded body 4. The overlapping length h in the longitudinal direction is preferably 0.1 mm to 10 mm, more preferably 2 mm to 7 mm. By making the length h greater than 0.1 mm, there is a tendency for the water vapor barrier properties, oxygen barrier properties, and aroma retention to be further improved. In addition, by making the length h less than 10 mm, the use of the relatively expensive cylindrical molded body 4 can be reduced, thereby suppressing the cost of the barrier stopper.

Furthermore, from the perspective of preventing the nozzle body 3 from cracking and exposing the cylindrical molded body 4, the nozzle body wall thickness D is preferably 0.2 mm to 2 mm, more preferably 0.4 mm to 1.5 mm. Here, in the nozzle body 3 having a complex cross-sectional shape, the wall thickness D represents the thickness of the thinnest portion.

〔Container with barrier cap〕

The container with a barrier stopper of this embodiment comprises a container and the barrier stopper mounted on the container, wherein the container is constructed using at least one selected from the group consisting of a laminated film having a resin layer (which contains a barrier resin), a laminated film having an aluminum foil layer, and a film deposited with a metal, wherein the resin layer has an oxygen permeability of not more than 10,000 mL·μm/m ² ·24 hrs·MPa (23°C·65% RH) and a water vapor permeability of not more than 1,000 g·μm/m ² ·24 hrs (38°C·90% RH).

Examples of the component of the container include at least one selected from the group consisting of a laminate film having a resin layer containing a barrier resin, a laminate film having an aluminum foil layer, and a metal-deposited film.

The resin layer containing the barrier resin has an oxygen permeability of not more than 10,000 mL·μm/m ² ·24 hrs·MPa (23°C·65% RH) and a water vapor permeability of not more than 1,000 g·μm/m ² ·24 hrs (38°C·90% RH). Except for constituting a container, the structure can be the same as that described for the barrier plug described above.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Preparation of Substitute Test Samples for Measuring Oxygen Transmission Rate, Water Vapor Transmission Rate, and Oxygen Transmission Rate Reduction Rate]

In the measurement of the oxygen permeability, water vapor permeability, and oxygen permeability reduction rate of the cylindrical molded article, a substitute measurement sample simulating the layer structure of the cylindrical molded article (resin type, lamination order, thickness ratio of each layer) is prepared, and the oxygen permeability, water vapor permeability, and oxygen permeability reduction rate of the cylindrical molded article are calculated from the measured values of the oxygen permeability, water vapor permeability, and oxygen permeability reduction rate of the film sample.

The surrogate test film is produced using a direct inflation device, using a single-layer die for monolayer films and a coextrusion multilayer die for laminated films, to achieve a predetermined composition ratio. The measured values of the surrogate test film's oxygen permeability, water vapor permeability, and oxygen permeability reduction rate are multiplied by the thickness of the resin layer containing the barrier resin to obtain the permeability per 1 μm. This allows estimation of the barrier properties of the resulting cylindrical molded article.

〔Oxygen Transmission Rate (OTR)〕

Oxygen transmission rate (OTR) was measured according to ASTM D-3985. Specifically, a Mocon OX-TRAN 2/20 was used to measure a substitute test specimen of a specified thickness at 23°C and 65% RH. The measured value was multiplied by the thickness of the resin layer containing the barrier resin to obtain the oxygen transmission rate per 1 μm of thickness (rounded off to the nearest decimal point).

Water Vapor Transmission Rate (WVTR)

Water vapor transmission rate (WVTR) is measured according to ASTM F-372. Specifically, a Mocon PERMATRAN-W398 is used to measure the water vapor transmission rate (WVTR) per 1 μm of thickness at 38°C and 90% RH using a substitute test specimen of a specified thickness. The measured value is multiplied by the thickness of the resin layer containing the barrier resin to obtain the water vapor transmission rate (rounded off to the nearest decimal point) per 1 μm of thickness.

〔Oxygen transmission rate reduction rate〕

The oxygen transmission rate reduction rate is measured according to ASTM D-3985. Specifically, the measurement is performed using a Mocon OX-TRAN 2/20 at 23°C and 90% RH on a substitute test specimen of a specified thickness. The measured value is multiplied by the thickness of the resin layer containing the barrier resin to obtain the oxygen transmission rate per 1 μm thickness at 90% RH (rounded off). The oxygen transmission rate reduction rate is calculated by dividing the oxygen transmission rate at 65% RH by the oxygen transmission rate at 90% RH (rounded off), and multiplying the result by 100%.

In Table 1, the oxygen permeability (mL·μm/m ² ·day·MPa), water vapor permeability (g·μm/m ² ·day), and oxygen permeability reduction rate of the cylindrical molded article are described without parentheses, while the oxygen permeability (mL/m ² ·day·MPa) and water vapor permeability (g/m ² ·day) of the substitute measurement sample are described with parentheses.

[Method for manufacturing a container with a barrier plug]

The cylindrical molded body obtained in the examples and comparative examples is inserted into the mouth body formed of polyethylene, and the cover is installed to obtain a barrier mouth plug. It should be noted that the resin composition obtained in the examples and comparative examples is continuously extruded into a sheet using a melt extrusion device. Then, it is adjusted to the same thickness as the tube in a cold water tank. The obtained sheet is cut and arranged on the cover body formed of polyethylene in a manner that becomes the part covering the mouth of the cover to obtain the cover. The barrier mouth plug obtained with the cover installed is installed in a bag formed of a laminated film having an aluminum foil layer to obtain a container with a barrier mouth plug.

〔Evaluation of room temperature storage properties〕

50 mL of soy sauce was placed in a container with a stopper obtained in the Examples and Comparative Examples and stored in a dark, constant temperature and humidity chamber at 23°C and 50% RH for 3 days. The soy sauce's L (lightness), a (green-red phase), and b (blue-yellow phase) were measured before and after storage using a colorimeter. The difference in the Lab values was used to calculate ΔE (color difference) = (ΔL) ^² + (Δa) ^² + (Δb) ^² (rounded to the nearest decimal point), and the degree of discoloration was observed. The evaluation was performed as follows: a ΔE of 0 to 7 indicates minimal discoloration and relatively good soy sauce quality; a ΔE greater than 7 and less than 12 indicates good quality; a ΔE greater than 12 and less than 14 indicates visible discoloration but usable; and a ΔE greater than 14 indicates severe discoloration and unusable.

[Evaluation of storage stability under high temperature and high humidity]

50 mL of soy sauce was placed in a container with a stopper obtained in the Examples and Comparative Examples and stored in a dark, constant temperature and humidity chamber at 40°C and 90% RH for 3 days. The soy sauce's L (lightness), a (green-red color), and b (blue-yellow color) were measured before and after storage using a colorimeter. The difference in the Lab values was used to calculate ΔE (color difference) = (ΔL) ^² + (Δa) ^² + (Δb) ^² (rounded to the nearest decimal point), and the degree of discoloration was observed. The evaluation was performed as follows: a ΔE of 0 to 7 indicates minimal discoloration and relatively good soy sauce quality; a ΔE greater than 7 and less than 12 indicates good quality; a ΔE greater than 12 and less than 14 indicates visible discoloration but usable; and a ΔE greater than 14 indicates severe discoloration and unusable.

[Fragrance retention evaluation]

The cylindrical molded articles obtained in the Examples and Comparative Examples were sealed on one side, 10 mL of ethanol was added, and the seal was sealed. With the sides of the cylinder horizontal, the articles were placed in a 5 L desiccator and sealed. After storage at 40°C for one day, the degree of alcohol odor leaking from the cylindrical molded articles into the desiccator was evaluated according to the following criteria.

○: There is absolutely no smell of alcohol.

△: Slight smell of alcohol.

×: There is a distinct smell of alcohol.

[Example 1]

1 wt% of epoxidized soybean oil as a heat stabilizer was mixed with PVDC-A resin (manufactured by Asahi Kasei Chemicals Co., Ltd.) with a vinylidene chloride (VDC)/methyl acrylate (MA) ratio of 95/5 (mass %) and a weight-average molecular weight of 80,000. The resulting resin composition was continuously extruded into a cylindrical shape using a melt extruder equipped with a cylindrical die. The outer diameter was then adjusted to 10 mm in a cold water bath equipped with an outer diameter calibration device to produce a single-layer tube with a thickness of 300 μm. Separately, the same resin composition was used using a direct inflation device to adjust the thickness to 30 μm, 1/10 of the tube thickness, to produce a single-layer film (surrogate measurement film). The oxygen and water vapor permeabilities of this substitute measurement film were measured.

[Example 2]

A single-layer tube having an outer diameter of 10 mm and a thickness of 300 μm was obtained in the same manner as in Example 1, except that PVDC-B resin (manufactured by ASAHI KASEI CHEMICALS) having a weight-average molecular weight of 80,000 and a ratio of vinylidene chloride (VDC) to methyl acrylate (MA) of 92/8 (mass %) was used instead of PVDC-A resin.

[Example 3]

A single-layer tube having an outer diameter of 10 mm and a thickness of 300 μm was obtained in the same manner as in Example 1, except that PVDC-C resin (manufactured by ASAHI KASEI CHEMICALS) having a vinylidene chloride (VDC)/vinyl chloride (VC) ratio of 89/11 (mass %) and a weight-average molecular weight of 80,000 was used instead of the PVDC-A resin.

[Example 4]

A single-layer tube having an outer diameter of 10 mm and a thickness of 100 μm was obtained in the same manner as in Example 1 except that the thickness was 100 μm.

[Example 5]

A single-layer tube having an outer diameter of 10 mm and a thickness of 500 μm was obtained in the same manner as in Example 1 except that the thickness was changed to 500 μm.

[Example 6]

Low-density polyethylene (PE-A (manufactured by ASAHI KASEI CHEMICALS, product name F1920)) was used for the inner and outer layers, and a resin composition obtained by mixing 1 wt% of epoxidized soybean oil as a heat stabilizer with PVDC-A resin was used for the middle layer. This composition was continuously extruded into a cylindrical shape using a melt extrusion machine equipped with a co-extrusion multi-layer cylindrical die. The outer diameter was then adjusted to 10 mm in a cold water bath equipped with an outer diameter calibration device, resulting in a three-layer tube with a thickness of 600 μm. Similarly, a three-layer film (surrogate test film) was produced using a co-extrusion multi-layer film molding machine with the same thickness ratio, but with the total thickness of each layer adjusted to 60 μm, 1/10 of the tube thickness. The oxygen and water vapor permeabilities of this surrogate test film were measured.

[Example 7]

A two-layer tube having an outer diameter of 10 mm and a thickness of 400 μm was obtained in the same manner as in Example 6 except that the outer layer composed of low-density polyethylene (PE-A) was not provided.

[Example 8]

A three-layer tube having an outer diameter of 10 mm and a thickness of 500 μm was obtained in the same manner as in Example 6 except that PVDC-B resin was used instead of PVDC-A resin.

[Example 9]

A two-layer tube having an outer diameter of 10 mm and a thickness of 400 μm was obtained in the same manner as in Example 7 except that PVDC-B resin was used instead of PVDC-A resin.

[Example 10]

A three-layer tube having an outer diameter of 10 mm and a thickness of 500 μm was obtained in the same manner as in Example 6 except that high-density polyethylene (PE-B (manufactured by Asahi Kasei Chemicals Co., Ltd., product name F371)) was used instead of low-density polyethylene (PE-A).

[Example 11]

A two-layer tube having an outer diameter of 10 mm and a thickness of 400 μm was obtained in the same manner as in Example 7 except that high-density polyethylene (PE-B) was used instead of low-density polyethylene (PE-A).

[Example 12]

Using a melt extrusion machine equipped with a co-extrusion multi-layer cylindrical die, the following components were continuously extruded into a cylindrical shape: low-density polyethylene (PE-A), ethylene-vinyl acetate copolymer (EVA-A (NUC Corporation, product name NUC3765D)), a resin composition obtained by mixing 1 wt% of epoxidized soybean oil as a heat stabilizer with PVDC-A resin, ethylene-vinyl acetate copolymer (EVA-A), and low-density polyethylene (PE-A), in that order from the inside. The outer diameter was then adjusted to 10 mm in a cold water bath equipped with an outer diameter calibration device, resulting in a five-layer tube with a thickness of 600 μm. Similarly, using a co-extrusion multi-layer film molding machine, the total thickness of each layer was adjusted to 60 μm, 1/10 of the tube thickness, at the same thickness ratio, to produce a five-layer film (surrogate measurement film). The oxygen and water vapor permeabilities of this substitute measurement film were measured.

[Example 13]

A low-density polyethylene (PE-A) was used for the inner layer, an ethylene-vinyl acetate copolymer (EVA-A) was used for the middle layer, and a resin composition obtained by mixing 1wt% of epoxidized soybean oil as a heat stabilizer with the PVDC-A resin was used for the outer layer. This was continuously extruded into a cylindrical shape using a melt extrusion device equipped with a co-extrusion multi-layer cylindrical die. The outer diameter was then adjusted to 10mm in a cold water tank with an outer diameter calibration device to obtain a three-layer tube with a thickness of 400μm. Furthermore, the same operation was performed using a co-extrusion multi-layer film forming device. The total thickness of each layer was adjusted to 1/10 of the tube thickness, i.e., 40μm, with the same thickness composition ratio, to obtain a three-layer film (substitute measurement film). The oxygen permeability and water vapor permeability of this substitute measurement film were measured.

[Example 14]

A five-layer tube having an outer diameter of 10 mm and a thickness of 600 μm was obtained in the same manner as in Example 12 except that ethylene-vinyl acetate copolymer (EVA-B (manufactured by NUC Corporation, product name NUC-3758)) was used instead of ethylene-vinyl acetate copolymer (EVA-A).

[Example 15]

A three-layer tube having an outer diameter of 10 mm and a thickness of 400 μm was obtained in the same manner as in Example 13 except that ethylene-vinyl acetate copolymer (EVA-B) was used instead of ethylene-vinyl acetate copolymer (EVA-A).

[Example 16]

A three-layer tube having an outer diameter of 10 mm and a thickness of 500 μm was obtained in the same manner as in Example 6 except that homopolypropylene (PP-A (manufactured by SunAllomer Ltd., product name PL500A)) was used instead of low-density polyethylene (PE-A).

[Example 17]

A two-layer tube having an outer diameter of 10 mm and a thickness of 400 μm was obtained in the same manner as in Example 16 except that the outer layer composed of homopolypropylene (PP-A) was not provided.

[Example 18]

Using a melt extrusion machine equipped with a co-extrusion multi-layer cylindrical die, the following layers were continuously extruded into a cylindrical shape: homopolypropylene (PP-A), adhesive resin, a resin composition obtained by mixing 1 wt% of epoxidized soybean oil as a heat stabilizer with PVDC-A resin, adhesive resin, and homopolypropylene (PP-A) in this order from the inside. The outer diameter was then adjusted to 10 mm in a cold water bath equipped with an outer diameter calibration device, resulting in a five-layer tube with a thickness of 600 μm. Similarly, using a co-extrusion multi-layer film molding machine, the total thickness of each layer was adjusted to 60 μm, 1/10 of the tube thickness, with the same thickness ratio, to produce a five-layer film (surrogate test film). The oxygen and water vapor permeabilities of this substitute test film were measured.

[Example 19]

A five-layer tube having an outer diameter of 10 mm and a thickness of 600 μm was obtained in the same manner as in Example 18 except that random polypropylene (PP-B (manufactured by SunAllomer Ltd., product name PB222A)) was used instead of homopolypropylene (PP-A).

[Example 20]

Homopolypropylene (PP-A) was used for the inner layer, an adhesive resin was used for the middle layer, and a resin composition obtained by mixing PVDC-A resin with 1 wt% of epoxidized soybean oil as a heat stabilizer was used for the outer layer. This was continuously extruded into a cylindrical shape using a melt extrusion machine equipped with a co-extrusion multi-layer cylindrical die. The outer diameter was then adjusted to 10 mm in a cold water tank equipped with an outer diameter calibration device, resulting in a three-layer tube with a thickness of 450 μm. Similarly, a three-layer film (surrogate test film) was obtained using a co-extrusion multi-layer film molding machine with the same thickness ratio, but with the total thickness of each layer adjusted to 45 μm, 1/10 of the tube thickness. The oxygen and water vapor permeabilities of this substitute test film were measured.

[Example 21]

A five-layer tube having an outer diameter of 10 mm and a thickness of 500 μm was obtained in the same manner as in Example 12, except that an outer layer formed of ethylene vinyl alcohol copolymer (EVOH) was provided instead of the outer layer formed of low-density polyethylene (PE-A), and an adhesive resin was used instead of the ethylene-vinyl acetate copolymer (EVA-A) of the inner layer.

[Comparative Example 1]

A single-layer tube with an outer diameter of 10 mm and a thickness of 150 μm was obtained in the same manner as in Example 1, except that ethylene vinyl alcohol copolymer was used instead of PVDC-A resin and the thickness was set to 150 μm. Separately, a single-layer film (surrogate measurement film) was obtained by adjusting the thickness to 15 μm, 1/10 of the tube thickness, using a melt extruder. The oxygen and water vapor permeabilities of this substitute measurement film were measured.

[Comparative Example 2]

A single-layer tube with an outer diameter of 10 mm and a thickness of 150 μm was obtained in the same manner as in Example 1, except that MXD6 polyamide resin (PA (Mitsubishi Gas Chemical Corporation, product name S6007)) was used instead of PVDC-A resin and the thickness was adjusted to 150 μm. Separately, a single-layer film (surrogate measurement film) was obtained in the same manner using a melt extruder, with the thickness adjusted to 15 μm, 1/10 of the tube thickness. The oxygen and water vapor permeabilities of this substitute measurement film were measured.

[Comparative Example 3]

Using a melt extrusion machine equipped with a co-extrusion multilayer cylindrical die, low-density polyethylene (PE-A) was continuously extruded into a cylindrical shape in the order, from the inside, of adhesive resin, ethylene vinyl alcohol copolymer (EVOH), adhesive resin, and low-density polyethylene (PE-A). The outer diameter was then adjusted to 10 mm in a cold water bath equipped with an outer diameter calibration device, resulting in a five-layer tube with a thickness of 450 μm. Similarly, using a co-extrusion multilayer film molding machine, the total thickness of each layer was adjusted to 45 μm, 1/10 of the tube thickness, with the same thickness ratio, to produce a five-layer film (surrogate test film). The oxygen and water vapor permeabilities of this substitute test film were measured.

[Comparative Example 4]

A five-layer tube having an outer diameter of 10 mm and a thickness of 500 μm was obtained in the same manner as in Comparative Example 3 except that a 150 μm intermediate layer made of MXD6 polyamide resin (PA) was used instead of the 100 μm intermediate layer made of ethylene vinyl alcohol copolymer (EVOH).

[Table 1]

Examples 1 to 21 show that when the oxygen and water vapor permeabilities are within the ranges of the present invention, the shelf life of the cylindrical molded articles is evaluated to be good. It is shown that when a resin with higher barrier properties is used, as in Examples 1 and 5, the shelf life of the cylindrical molded articles is further improved. Examples 1 to 21 show that the oxygen and water vapor permeabilities of the vinylidene chloride copolymers, whether single-layer or multi-layer, are good, and the shelf life of the cylindrical molded articles is also good. It is shown that when the oxygen and water vapor permeabilities are outside the ranges of the present invention, as in Comparative Examples 1 to 4, a cylindrical molded article with satisfactory shelf life cannot be obtained.

Industrial applicability

The barrier cap of the present invention has industrial applicability as a cap for various packages.

Claims (7)

1. A stop valve having a mouthpiece body that can be installed in a container and a cylindrical molded body inserted into the mouthpiece body. The wall thickness of the mouth part is 0.2–2 mm. The thickness of the cylindrical molded body is 50–1000 μm. The cylindrical molded body has a resin layer containing barrier resin. The melting point of the barrier resin is higher than that of the resin constituting the mouthpiece body. The thickness of the resin layer is 25–700 μm. The oxygen permeability of the resin layer at 23°C and 65% RH is below 10000 mL·μm/ ^m² ·24hrs·MPa. The water vapor transmission rate of the resin layer at 38°C and 90% RH is less than 1000 g·μm/ ^m² ·24hrs, and The oxygen permeability reduction rate is obtained by dividing the oxygen permeability of the resin layer at 23°C and 65% RH by the oxygen permeability at 23°C and 90% RH under high humidity, and then multiplying by 100. The result is 80%–100%. The cylindrical molded body forms a discharge flow path for discharging the contents of the container to the outside. The overlap length between the container and the cylindrical molded body in the length direction of the cylindrical molded body is 0.1 to 10 mm. 2. The barrier plug as claimed in claim 1, wherein the mouthpiece body contains a polyolefin resin. 3. The barrier plug as claimed in claim 1 or 2, wherein the mouthpiece body has a layer covering at least a portion of the end face of the cylindrical body opposite to the end that can be installed on the container. The coating layer coats the end face of the resin layer containing the barrier resin. 4. The barrier plug as claimed in claim 1 or 2, wherein the barrier resin comprises vinylidene chloride copolymer and/or ethylene-vinyl alcohol copolymer. 5. The barrier plug as claimed in claim 1 or 2, wherein the cylindrical molded body has an inner layer and an outer layer. The inner layer contains a polyolefin resin. The outer layer is the resin layer. 6. The barrier plug as claimed in claim 1 or 2, wherein the cylindrical molded body has an inner layer, one or more intermediate layers, and an outer layer. The inner layer contains a polyolefin resin. The outer layer and/or the middle layer are the resin layers. 7. A container with a barrier plug, comprising a container and a barrier plug as described in any one of claims 1 to 6, wherein, The container is composed of at least one selected from the group consisting of a laminated film having a resin layer containing a barrier resin, a laminated film having an aluminum foil layer, and a film with evaporated metal, wherein the oxygen permeability of the resin layer at 23°C and 65%RH is less than 10000 mL·μm/ ^m² ·24hrs·MPa, and the water vapor permeability at 38°C and 90%RH is less than 1000 g·μm/ ^m² ·24hrs.