JP2023132334A - Container and preform thereof - Google Patents

Abstract

To provide a container which compatibly has high barrier properties and prevents delamination, and a preform of the container.SOLUTION: A container according to the present invention comprises at least a base material layer including thermoplastic resin and a gas barrier layer including gas barrier resin, wherein the gas barrier layer is an innermost layer, the thermoplastic resin contains mechanical recycled polyester, and the gas barrier resin has a melt flow rate of 0.2 g/10 min or more and 8.0 g/10 min or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a container and a preform thereof.

Polyesters such as polyethylene terephthalate have excellent mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency, etc., and are inexpensive, so they are widely used in the manufacture of containers for filling beverages, etc. . In particular, in order to sustainably maintain the quality of the contents, there is a need to develop containers with higher gas barrier properties, especially carbon dioxide gas barrier properties.

For example, Patent Document 1 discloses a multilayer preform having a multilayer structure consisting of inner and outer layers made of polyester resin and an intermediate layer made of a blend of polyester resin and aromatic polyamide resin, and a biaxially stretched multilayer preform. A multilayer stretch blow molded container is disclosed. The multilayer stretch blow-molded container has excellent gas barrier properties as a whole, mainly because the intermediate layer contains a gas barrier aromatic polyamide resin.

International Publication No. 2017/010516 pamphlet

In a container such as the multilayer stretch blow-molded container disclosed in Patent Document 1, in which a layer having gas barrier properties is provided in the middle of the multilayer structure, carbon dioxide gas generated from the contents of the container (for example, a carbonated beverage) is transferred to the middle layer. Although it is possible to prevent carbon dioxide gas from passing through the inner layer, it is not possible to prevent carbon dioxide gas from passing through the inner layer, and carbon dioxide gas bubbles may be accumulated between the intermediate layer and the inner layer. As a result, the transparency of the container may be lost or the adhesion between the layers may be impaired.
The present inventors have discovered that by providing a gas barrier layer as the innermost layer of a container, it is possible to suppress the accumulation of air bubbles between the layers and prevent delamination, while maintaining the gas barrier properties of the container.

The present invention has been made in view of the above, and an object to be solved is to provide a container that can have both high gas barrier properties and prevention of delamination.

The present invention includes at least a base layer containing a thermoplastic resin and a gas barrier layer containing a gas barrier resin,
the gas barrier layer is the innermost layer,
the thermoplastic resin contains polyester,
The container has a melt flow rate of the gas barrier resin of 0.2 g/10 minutes or more and 8.0 g/10 minutes or less.

In the container according to the present invention, the polyester may be one or more selected from virgin polyester and recycled polyester.

In the container according to the present invention, the recycled polyester may be one or more selected from mechanically recycled polyester and chemically recycled polyester.

In the container according to the present invention, the polyester may contain a biomass-derived polyester.

In the container according to the present invention, the base material layer may have a biomass degree of 3% or more.

In the container according to the present invention, the gas barrier resin may be polyamide.

In the container according to the present invention, the gas barrier resin may be an aromatic polyamide.

In the container according to the present invention, the gas barrier resin may be meta-xylene adipamide.

In the container according to the present invention, the gas barrier layer may contain a transition metal catalyst.

The container according to the invention comprises a mouth, a neck, a shoulder, a body and a bottom,
The cross-sectional thickness of the gas barrier layer in the body may be 0.01 mm or more and 0.49 mm or less.

In the container according to the present invention, the cross-sectional thickness of the base layer in the body may be 0.01 mm or more and 0.49 mm or less.

The present invention is a preformed body of the container.

According to the present invention, it is possible to provide a container capable of achieving both high gas barrier properties and prevention of delamination, and a preform of this container.

1 is a schematic half-sectional view showing an embodiment of a bottle which is an example of a container of the present invention. 1 is a schematic half-sectional view showing an embodiment of a bottle which is an example of a container of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an embodiment of a preform that is an example of a preformed body of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an embodiment of a preform that is an example of a preformed body of the present invention.

<Container>
The container of the present invention includes at least a base layer and a gas barrier layer.
In addition, in this specification, a "container" means a molded object which accommodates an article. Examples of the container include molded bodies such as compression molded bodies, injection molded bodies, blow molded bodies, and thermoformed bodies. Specific containers include, for example, bottles, vials, cups, trays, and packs.

(Base material layer)
In the container of the present invention, the base layer can maintain the shape of the container and contains a thermoplastic resin. Examples of the thermoplastic resin include polyolefins such as polyethylene and polypropylene, polyesters such as polycarbonate, polyvinyl chloride, and polyethylene terephthalate, polyamides such as nylon 6 and nylon 6,6, and mixtures thereof. Among these, the base material layer contains polyester from the viewpoint of gas barrier properties and strength. From the viewpoint of recyclability, the base layer preferably contains polyethylene terephthalate.

In this specification, "polyester" means a polymer made into a polymer by ester bonds. Such a polyester is usually obtained by polycondensing a dicarboxylic acid compound and a diol compound.
Examples of dicarboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethylmalonic acid, and adamantane. Dicarboxylic acid, norbornene dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1, 8-naphthalene dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendane dicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, 9,9'-bis Examples include (4-carboxyphenyl)fluorenic acid and ester derivatives thereof.
Examples of diol compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. Diethanol, decahydronaphthalene dimethanol, decahydronaphthalene diethanol, norbornane dimethanol, norbornane dimethanol, tricyclodecane dimethanol, tricyclodecaneethanol, tetracyclododecane dimethanol, tetracyclododecane diethanol, decalin dimethanol, decalin diethanol, 5 -Methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxy cyclohexyl)propane, 2,2-bis(4-(2-hydroxyethoxy)cyclohexyl)propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamandiol , paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, pentaerythritol, and bis-β-hydroxyethyl terephthalate (BHET).
The polyester is preferably polyethylene terephthalate or modified polyethylene terephthalate obtained by polymerizing a raw material monomer of polyethylene terephthalate and a copolymerization monomer.

The polyester may contain monomers other than dicarboxylic acid compounds and diol compounds as long as the characteristics of the present invention are not impaired, but the content thereof is preferably 10 mol% or less based on the total structural units. , more preferably 5 mol% or less, and still more preferably 3 mol% or less.

The polyester may be one that has been polymerized using a polymerization catalyst. Examples of the polymerization catalyst include a manganese (Mn) catalyst, a titanium (Ti) catalyst, an aluminum (Al) catalyst, a lithium (Li) catalyst, a germanium (Ge) catalyst, and an antimony (Sb) catalyst.

The above polyester is preferably one or more selected from virgin polyester and recycled polyester. Among these, in the present invention, it is preferable to use recycled polyester from the viewpoint of reducing environmental load. In this specification, "virgin polyester" means polyester that has not been recycled, and "recycled polyester" refers to polyester that has been recycled by collecting used containers and other products shipped to the market. shall mean.
In addition, recycled polyester includes polyester obtained by decomposing collected used polyester containers to the monomer level and polymerizing them again (hereinafter referred to as "chemical recycled polyester"), and collected used products. Polyester (hereinafter referred to as polyester), which is obtained by sorting, crushing, and washing to remove contaminants and foreign substances to obtain flakes, is further treated at high temperature and reduced pressure for a certain period of time to remove contaminants inside the resin. (referred to as "mechanically recycled polyester"). Among these, it is preferable to use mechanically recycled polyester. The mechanically recycled polyester may contain one type of catalyst, or may contain two or more types of catalysts. In this case, the mechanically recycled polyester may include, for example, one or more of Sb-catalyzed polyester, Mn-catalyzed polyester, Ti-catalyzed polyester, Al-catalyzed polyester, Li-catalyzed polyester, and Ge-catalyzed polyester.

It is known that mechanically recycled polyester has a different content ratio of antimony (Sb) element, sodium (Na) element, calcium (Ca) element, or magnesium (Mg) element than virgin polyester and chemically recycled polyester. Specifically, the mechanically recycled polyester contains Sb element in a proportion of 20.0 mg/L or more and 54.0 mg/L or less, Na element in a proportion of 12.0 mg/L or more, and Ca element in a proportion of 4.0 mg/L or more. It is known to contain the Mg element at a ratio of 2.5 mg/L or more. Therefore, mechanically recycled polyester can be distinguished from virgin polyester and chemically recycled polyester depending on whether the polyester satisfies one or more of these content ratios.
Furthermore, in the mechanically recycled polyester, the content ratio of Sb element is preferably 25.0 mg/L or more and 50.0 mg/L or less, the content ratio of Na element is preferably 14.0 mg/L or more, and the content ratio of Ca element is 4 .5 mg/L or more is preferable, and the content ratio of Mg element is preferably 3.0 mg/L or more.

In the present invention, the content of mechanically recycled polyester is preferably 10 parts by mass or more and 90 parts by mass or less, and 60 parts by mass or more and 80 parts by mass or less, based on 100 parts by mass of the total resin material contained in the container. It is more preferable.

Polyester can be classified not only into virgin polyester and recycled polyester, but also into fossil fuel-derived polyester and biomass-derived polyester. In addition, in this specification, "fossil fuel-derived polyester" means a polyester that does not contain a biomass-derived monomer as a constituent unit, and "biomass-derived polyester" means a polyester that contains a biomass-derived monomer as a constituent unit. It shall be. Examples of biomass-derived monomers include biomass-derived ethylene glycol.

In the present invention, from the viewpoint of reducing environmental load, it is preferable that the polyester contains biomass-derived polyester. Furthermore, the biomass-derived monomer may be contained in the virgin polyester as a structural unit, or may be contained in the recycled polyester as a structural unit. That is, the biomass-derived polyester may be a non-recycled polyester (biomass-derived virgin polyester) or a recycled polyester (biomass-derived recycled polyester).

As an example, the biomass degree of the base material layer is preferably 3% or more. "Biomass degree" is a value obtained by measuring the content of carbon derived from biomass by radiocarbon (C14) measurement. Carbon dioxide in the atmosphere contains C14 at a constant rate (105.5 pMC). For this reason, it is known that the C14 content in plants that grow by taking in carbon dioxide from the atmosphere, such as corn, is about 105.5 pMC. It is also known that fossil fuels contain almost no C14. Therefore, by measuring the proportion of C14 contained in all carbon atoms in the base material layer, the proportion of carbon derived from biomass can be calculated.

For example, when the content of C14 in the base material layer is P _C14 , the content P _bio of carbon derived from biomass is defined as in the following formula (1).
P _bio (%) = P _C14 /105.5×100 (1)
The degree of biomass, or P _bio , is the value of C14 content obtained by a radiocarbon (C14) measurement method based on ASTM-D6866. Note that pMC is an abbreviation for Percent Modern Carbon.

For example, polyethylene terephthalate is obtained by polymerizing ethylene glycol containing 2 carbon atoms and terephthalic acid containing 8 carbon atoms at a molar ratio of 1:1, so if only biomass-derived diol units are used as ethylene glycol, The biomass-derived carbon content P _bio in the biomass polyester is 20%. In the present invention, the content of biomass-derived carbon (biomass degree) determined by radiocarbon (C14) measurement is preferably 3% or more and 20% or less, and 10% or less, based on the total carbon in the base material layer. It is more preferably 19% or less, and even more preferably 16% or more and 18% or less. If the content of biomass-derived carbon in the base material layer is less than 3%, the effect as a carbon offset material will be poor. On the other hand, from the perspective of achieving carbon neutrality, it is preferable that the content of biomass-derived carbon in the base material layer be close to 20%, but due to problems in the manufacturing process and physical properties of the container, the base material layer does not contain additives. It is preferable to include. Therefore, the content of biomass-derived carbon is more preferably 19% or less, and even more preferably 18% or less, based on the total carbon in the base material layer.

That is, when only biomass-derived diol units are used as ethylene glycol, the biomass degree is 20%, and since the preferable biomass degree of the base material layer is 3% to 20%, biomass-derived ethylene is used as the diol unit. The biomass polyester obtained using glycol and a fossil fuel-derived dicarboxylic acid as a dicarboxylic acid unit has a content of 15 (=3%/20%) or more by mass 100 ( =20%/20%) means that the content is preferably less than % by mass.

From the viewpoint of recyclability, the content of one type of thermoplastic resin in the base material layer is preferably 85% by mass or more, more preferably 97% by mass or more.

The base layer may contain additives within a range that does not impair the characteristics of the present invention. Examples of additives include oxygen absorbers, plasticizers, ultraviolet stabilizers, antioxidants, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, friction reducers, slip agents, and mold release agents. agents, antioxidants, ion exchange agents, and the like. These additives can be used alone or in combination of two or more.

The base material layer may have a single layer structure or a multilayer structure of two or more layers. Furthermore, when the base material layer has a multilayer structure, each layer may have the same composition or may have different compositions within a range that does not impair the characteristics of the present invention.

The thickness of the cross section of the base layer is preferably 0.01 mm or more and 0.49 mm or less, more preferably 0.05 mm or more and 0.40 mm or less.
Note that the thickness of the cross section of the base material layer can be measured, for example, at the body of the container. The cross-sectional thickness of the base layer means the thickness of the cross-section at the thinnest point.

The base material layer is preferably subjected to surface treatment. Examples of surface treatments include corona treatment, low-temperature plasma treatment, and flame treatment. By performing such a surface treatment, the wettability of the surface of the base material layer can be improved, and the adhesion between the base material layer and a layer in contact with the base material layer can be improved.

(Gas barrier layer)
The container of the present invention includes a gas barrier layer. The gas barrier layer is provided as the innermost layer. The gas barrier layer may be provided from the upper end of the mouth part to the lower end of the bottom part, or may be provided from a part of the container, for example, from the support ring to the lower end of the bottom part.

The gas barrier layer contains at least one gas barrier resin, such as polyamide, ethylene-vinyl acetate copolymer (EVOH), ethylene-vinyl alcohol copolymer, polyglycol (PGA), polyvinylidene chloride copolymer ( PVDC), polyacrylonitrile, polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), and styrene-isobutylene-styrene copolymer. Polyamides include aromatic polyamides such as metaxylene adipamide (MXD-6), and aliphatic polyamides such as nylon 6, nylon 6,6 and nylon 6/nylon 6,6 copolymer. Among these, polyamide is preferred, aromatic polyamide is more preferred, and meta-xylene adipamide is even more preferred.

In the present invention, the melt flow rate (MFR) of the gas barrier resin is 0.2 g/10 minutes or more and 8.0 g/10 minutes or less, preferably 0.4 g/10 minutes or more and 6.0 g/10 minutes or less, More preferably 1 g/10 minutes or more and 4 g/10 minutes or less. In this specification, the melt flow rate is a value measured at a temperature of 275° C. and a load of 0.325 kg in accordance with ISO1133. If the melt flow rate of the gas barrier resin is 0.2 g/10 minutes or more, the load during molding can be reduced. Further, if the melt flow rate of the gas barrier resin is 8.0 g/10 minutes or less, the strength of the container can be improved.

The content of the gas barrier resin in the gas barrier layer is preferably 40% by mass or more, more preferably 95% by mass or more. Further, the gas barrier layer may be completely composed of gas barrier resin. By setting the content of the gas barrier resin in the gas barrier layer to 40% by mass or more, the gas barrier properties of the container can be improved.
Further, the content of the gas barrier resin in the container is preferably 10 parts by mass or more and 90 parts by mass or less, and 20 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total resin material contained in the container. It is more preferable. By setting the content of the gas barrier resin to 10 parts by mass or more based on 100 parts by mass of the total amount of resin materials contained in the container, the gas barrier properties of the container can be further improved. By setting the content of the gas barrier resin to 90 parts by mass or less with respect to 100 parts by mass of the total amount of resin materials contained in the container, the content of the thermoplastic resin contained in the container can be relatively increased, The strength and recyclability of the container can be improved.

When the gas barrier layer contains polyamide as the gas barrier resin, the gas barrier layer preferably contains a transition metal catalyst. Thereby, the gas barrier properties of the container can be further improved.
Examples of the metal component of the transition metal catalyst include iron, cobalt, nickel, copper, silver, titanium, zirconium, chromium, and manganese. The transition metal catalyst is contained in the gas barrier layer in the form of an inorganic acid salt, an organic acid salt, or a complex salt of the above-mentioned metal component, and examples of the inorganic acid salt include chloride halides, oxyacid salts, and silicates. Examples of organic acid salts include propionates, butanoates, stearates, and oxalates, and examples of complex salts include complexes with β-ditones and β-keto acid esters. .

The gas barrier layer may contain an oxygen absorbent. Oxygen absorbers include reducing iron, reducing zinc, reducing tin, lower metal oxides (ferrous oxide, triiron tetroxide), and reducing metal compounds (iron carbide, iron silicon, iron carbonyl, hydroxide). iron), etc.

The gas barrier layer may contain resins other than gas barrier resins as long as the characteristics of the present invention are not impaired, such as (meth)acrylic resins, vinyl resins, polyolefins, polyesters, and cellulose resins. Among these, the gas barrier layer preferably contains polyester from the viewpoint of improving adhesion with the base material layer and preventing delamination. The content of polyester in the gas barrier layer is preferably 3% by mass or more and 60% by mass or less. By setting the content of polyester to 3% by mass or more, the adhesion to the base layer can be further improved. By setting the polyester content to 60% by mass or less, the content of the gas barrier resin in the gas barrier layer can be increased.

The gas barrier layer may contain additives within the range that does not impair the characteristics of the present invention, such as plasticizers, ultraviolet stabilizers, antioxidants, color inhibitors, matting agents, deodorants, and Examples include a flame agent, a weathering agent, an antistatic agent, a yarn friction reducing agent, a slip agent, a mold release agent, an antioxidant, an ion exchange agent, and a coloring agent.

The thickness of the gas barrier layer is preferably 0.01 mm or more and 0.49 mm or less, more preferably 0.05 mm or more and 0.40 mm or less.
By setting the thickness of the gas barrier layer to 0.01 mm or more, the gas barrier properties of the container can be further improved.
By setting the thickness of the gas barrier layer to 0.49 mm or less, the weight of the container can be reduced and the blow moldability of the container can be improved.
Note that the thickness of the gas barrier layer means the thickness at the thinnest point in the body of the container.

Hereinafter, the structure of the container of the present invention in one embodiment will be described using a bottle as an example.

1 and 2 are schematic half-sectional views showing an embodiment of a bottle, which is an example of the container of the present invention. The bottle 1 has a gas barrier layer 11 and a base material layer 12, as shown in FIGS. 1 and 2.
In one embodiment, as shown in FIGS. 1 and 2, the bottle 1 includes a mouth portion 13, a neck portion 10 provided below the mouth portion 13, a shoulder portion 14 provided below the neck portion 10, and a shoulder portion 14 provided below the neck portion 10. It includes a body part 15 provided below and a bottom part 16 provided below the body part 15. In one embodiment, the shoulder portion 14 is provided between the neck portion 10 and the body portion 15 and has a cylindrical shape whose diameter gradually increases from the neck portion 10 side to the body portion 15 side.
The gas barrier layer 11 may be provided in the area where the contents and the container are in contact, as shown in FIG. 1, or may be provided from the upper end of the mouth portion 13 to the bottom portion 16, as shown in FIG. .
In one embodiment, the mouth portion 13 includes a threaded portion 17 into which a cap is screwed, a cover 18 below the threaded portion 17, and a support ring 19 below the cover 18, as shown in FIGS. 1 and 2.

In this specification, "upper" and "lower" respectively refer to the upper and lower parts of the bottle 1 when it is erected (FIGS. 1 and 2).

The shape of the bottom portion 16 is not particularly limited, but for example, when the content is a carbonated drink such as natural sparkling water, it is preferably petaloid shaped as shown in FIGS. 1 and 2. . This can prevent the bottle 1 from deforming when the inside becomes high positive pressure.

In the container of the present invention, the oxygen permeability is preferably 0.100 cc/day/bottle/0.21 atm or less, more preferably 0.070 cc/day/bottle/0.21 atm, and even more preferably 0.070 cc/day/bottle/0.21 atm or less. It is not more than .050 cc/day・bottle・0.21 atm, and even more preferably not more than 0.040 cc/day・bottle・0.21 atm.
In this specification, oxygen permeability is measured using an oxygen permeability measuring device (for example, manufactured by MOCON, trade name: OX-TRAN 2/20) in accordance with JIS K 7126-2:2006. This value is measured under the conditions of , 23° C., and 40% RH, and is a value obtained by measuring the entire container whose mouth is closed with a jig and dividing it by the surface area of the entire container excluding the mouth.

In the container of the present invention, carbon dioxide loss is preferably 20% or less, more preferably 17% or less, and even more preferably 15% or less.
Note that in this specification, carbon dioxide gas loss is the rate at which the gas volume of carbon dioxide gas decreases during storage of a container, and is determined as follows.
Make a hole in the cap of the container filled with carbonated water using a measuring jig, and insert the sensor of a gas volume meter (manufactured by Bixl, product name: DGV-1) through the hole. After shaking the container vigorously with the sensor, record the gas pressure displayed and measure the gas volume. The gas volume was measured 30 minutes after filling the carbonated water and after the carbonated water was filled and stored at 22°C and 40% RH for 12 weeks, and the rate at which the gas volume decreased during storage was calculated. Carbon dioxide gas loss.

The cross-sectional thickness of the container of the present invention is preferably 0.1 mm or more and 0.5 mm or less, more preferably 0.15 mm or more and 0.30 mm or less.
Note that the thickness of the cross section of the container can be measured, for example, at least at the body of the container, which has a base layer and a gas barrier. The cross-sectional thickness of the container means the thickness of the cross-section at the thinnest point.

The capacity/weight of the container of the present invention is preferably 5 mL/g or more and 50 mL/g or less, more preferably 8 mL/g or more and 45 mL/g or less.
By setting the capacity/weight of the container to 5 mL/g or more, the weight of the container can be reduced and the blow moldability of the container can be improved.
Further, by setting the capacity/weight of the container to 50 mL/g or less, the strength of the container can be improved.

The container of the present invention may include layers other than the base layer and the gas barrier layer as long as the characteristics of the present invention are not impaired. For example, the outer surface of the container may be printed and provided with a printed layer. Images formed by printing are not particularly limited, and include, for example, patterns and characters.
Printing can be performed by a known method. Examples of the printing method include an inkjet method, a gravure printing method, an offset printing method, a flexographic printing method, a thermal transfer method, a silk screen method, a pad method, a hot stamp method, and a cold stamp method.
Furthermore, a printed container can be obtained by blow molding a printed preform.

<Preformed body>
The preformed body of the present invention is a molded body before blow molding the container of the present invention, and is used for manufacturing the container of the present invention. The shape of the preform can be appropriately selected depending on the shape of the container after blow molding.

Hereinafter, one embodiment of the structure of the preform of the present invention will be described by exemplifying a preform.

In one embodiment, preform 23 includes a gas barrier layer 24 and a base layer 25, as shown in FIGS. 3 and 4.
In one embodiment, preform 23 includes a mouth 26, a body 27, and a bottom 28, as shown in FIGS. 3 and 4. Among these, the mouth part 26 corresponds to the mouth part 13 of the bottle 1 described above, and has substantially the same shape as the mouth part 13. Further, the body portion 27 corresponds to the neck portion 10, shoulder portion 14, and body portion 15 of the bottle 1, and has a substantially cylindrical shape. The bottom portion 28 corresponds to the bottom portion 16 of the bottle 1 and has a substantially hemispherical shape.

(Gas barrier layer)
The gas barrier layer 24 may be provided from the lower end of the mouth 26 to cover the bottom 28, as shown in FIG. 3, or may be provided from the upper end of the mouth 26 to cover the bottom 28, as shown in FIG. It may be. Further, it may be provided so as to cover the trunk section 27 and the bottom section 28 (not shown).

As for the material constituting the gas barrier layer in the preform of the present invention, the same materials as those constituting the gas barrier layer in the container of the present invention can be used.

The thickness of the gas barrier layer in the preform is preferably 0.3 mm or more and 3.2 mm or less, and preferably 0.4 mm or more and 3.0 mm or less.
By setting the thickness of the gas barrier layer in the preform to 0.3 mm or more, the gas barrier properties of the container can be further improved.
Furthermore, by setting the thickness of the gas barrier layer in the preform to 3.2 mm or less, it is possible to improve blow moldability when manufacturing a container from the preform, and to reduce the weight of the manufactured container. .
Note that the thickness of the gas barrier layer means the thickness at the thinnest part in the body of the preform.

(Base material layer)
The material constituting the base layer in the preform of the present invention can be the same as the material constituting the base layer in the container of the present invention.

The thickness of the base material layer in the preform is preferably 0.3 mm or more and 3.2 mm or less, more preferably 0.4 mm or more and 3.0 mm or less.
By setting the thickness of the base layer in the preform to 0.3 mm or more, the strength of the container can be improved.
In addition, by setting the thickness of the base material layer in the preform to 3.2 mm or less, it is possible to improve blow moldability when manufacturing a container from the preform, and to reduce the weight of the manufactured container. can.
Note that the thickness of the base material layer means the thickness at the thinnest part in the body of the preform.

(Container manufacturing method)
The container of the present invention can be manufactured by co-injection molding at least the materials constituting the base layer and the gas barrier layer described above to prepare a preform, and then blow molding the preform. Blow molding can be performed by a conventionally known method.
When the preform has a structure of three or more layers and the gas barrier layer is formed on a part of the preform (for example, from the support ring to the lower end of the bottom), the method disclosed in JP-A No. 2008-94454 can be used. It is preferred to use a hot runner nozzle.

Further, the container of the present invention can also be manufactured by using two-color molding or insert molding.
Further, in the container of the present invention, a resin composition containing at least a gas barrier resin is injection molded into an internal mold, a gas barrier layer is formed, the internal mold is retracted, and a gap between the internal mold and the gas barrier layer is formed. It can be manufactured by providing a gap and injection molding a resin composition containing at least a thermoplastic resin into the gap to form a base material layer.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
Virgin polyester (germanium catalyst polyethylene terephthalate, manufactured by Mitsui Chemicals, J-125S) and gas barrier resin (methaxylene adipamide, manufactured by Mitsubishi Gas Chemical, MX nylon S6007, melt flow rate: 2g/10 minutes) were prepared.
These were co-injected using an injection molding machine to create a preform with the structure shown in Figure 3, which includes a gas barrier layer made of gas barrier resin and a base material layer made of virgin polyester from the inside. did.
The amount of virgin polyester used was adjusted to 80 parts by mass, and the amount of gas barrier resin used was adjusted to 20 parts by mass with respect to 100 parts by mass of the resin material constituting the preform.
The thickness of the body of the preform was 2.8 mm, and the basis weight was 22 g.

Next, the preform was heated to 110° C. and subjected to biaxial stretch blow molding in a blow mold to produce a bottle having the structure shown in FIG. 1. The content of the bottle was 350 mL.

[Example 2]
Same as Example 1 except that MX nylon S6001 (methaxylene adipamide, manufactured by Mitsubishi Gas Chemical Co., Ltd., melt flow rate: 7 g/10 minutes) was used as the gas barrier resin instead of MX nylon S6007. A bottle was made.

[Example 3]
Example 1 except that MX nylon S6121 (methaxylene adipamide, manufactured by Mitsubishi Gas Chemical Co., Ltd., melt flow rate: 0.5 g/10 min) was used as the gas barrier resin instead of MX nylon S6007. A bottle was made in the same manner.

[Comparative example 1]
A bottle was produced in the same manner as in Example 1 except that the gas barrier resin was not used. The bottle obtained in Comparative Example 1 was a single-layer bottle that did not have a gas barrier layer and only had a base material layer.

[Comparative example 2]
A bottle was produced in the same manner as in Comparative Example 1, except that mechanically recycled polyester (manufactured by Kyoei Sangyo Co., Ltd., NA-BT7906) was used for the base layer instead of virgin polyester. The bottle obtained in Comparative Example 2 was a single-layer bottle that did not have a gas barrier layer and only had a base material layer.

<Gas barrier evaluation>
The oxygen permeability of the bottles obtained in the above Examples and Comparative Examples was measured to evaluate the gas barrier properties of the bottles. Oxygen permeability was measured in accordance with JIS K 7126-2:2006 using an oxygen gas permeability measuring device (manufactured by MOCON, product name: OX-TRAN2/20) at 23°C and 40% RH. The test was carried out under the following conditions. Note that the oxygen permeability value is a value obtained by measuring the entire bottle whose mouth is closed with a jig and dividing it by the surface area of the entire bottle excluding the mouth. The measurement results are shown in Table 1.

In addition, the gas volume of the bottles obtained in the above Examples and Comparative Examples was measured to determine the carbon dioxide loss, and the gas barrier properties of the bottles were evaluated. A hole was made in the cap of the bottle filled with carbonated water using a measuring jig, and a sensor of a gas volume meter (manufactured by Bixl, trade name: DGV-1) was inserted through the hole. The gas pressure displayed after shaking the bottle vigorously with the sensor was recorded to measure the gas volume. The gas volume was measured 30 minutes after filling the carbonated water and after the carbonated water was filled and stored at 22°C and 40% RH for 12 weeks, and the rate at which the gas volume decreased during storage was calculated. Carbon dioxide gas loss. The measurement results are shown in Table 1.

<Evaluation of delamination>
Further, after measuring the gas volume after 12 weeks of storage, the appearance of the bottle was observed, and the presence or absence of delamination was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.

(Evaluation criteria)
○: No delamination.
×: There was delamination.

As is clear from Table 1 above, it can be seen that the container of the present invention can achieve both high gas barrier properties and prevention of delamination.

1: Bottle 10: Neck 11: Gas barrier layer 12: Base material layer 13: Mouth 14: Shoulder 15: Body 16: Bottom 17: Threaded portion 18: Cover 19: Support ring 20: Recessed portion 21: Ground portion 22 : Panel part 23: Preform 24: Gas barrier layer 25: Base material layer 26: Mouth part 27: Body part 28: Bottom part

Claims (12)

At least a base material layer containing a thermoplastic resin and a gas barrier layer containing a gas barrier resin,
the gas barrier layer is the innermost layer,
the thermoplastic resin contains polyester,
A container, wherein the gas barrier resin has a melt flow rate of 0.2 g/10 minutes or more and 8.0 g/10 minutes or less. The container according to claim 1, wherein the polyester is one or more selected from virgin polyester and recycled polyester. The container according to claim 2, wherein the recycled polyester is one or more selected from mechanically recycled polyester and chemically recycled polyester. The container according to any one of claims 1 to 3, wherein the polyester contains a biomass-derived polyester. The container according to any one of claims 1 to 4, wherein the base material layer has a biomass degree of 3% or more. The container according to any one of claims 1 to 5, wherein the gas barrier resin is polyamide. The container according to any one of claims 1 to 6, wherein the gas barrier resin is an aromatic polyamide. The container according to any one of claims 1 to 7, wherein the gas barrier resin is meta-xylene adipamide. The container according to any one of claims 1 to 8, wherein the gas barrier layer contains a transition metal catalyst. Comprising a mouth, a neck, a shoulder, a torso, and a bottom,
The container according to any one of claims 1 to 9, wherein the cross-sectional thickness of the gas barrier layer in the body is 0.01 mm or more and 0.49 mm or less. The container according to claim 10, wherein the cross-sectional thickness of the base layer in the body is 0.01 mm or more and 0.49 mm or less. A container preform according to any one of claims 1 to 11.

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