JP2020183250A - Multilayer container and multilayer preform - Google Patents

Abstract

To provide a multilayer container having high sanitation performance and high environmental load reduction performance.SOLUTION: A multilayer container according to the present invention comprises a mouth part, a shoulder part, a trunk part and a bottom part, and has an inner layer and an outer layer. The inner layer is constituted of virgin polyester, and the outer layer is constituted of recycled polyester. The virgin polyester constituting the inner layer is one or more polyester selected from manganese catalyst polyester, titanium catalyst polyester, aluminum catalyst polyester, lithium catalyst polyester and germanium catalyst polyester. The inner layer is provided in a range from an upper end of the mouth part to the bottom part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a multi-layer container and a multi-layer preform used in the manufacture of the multi-layer container.

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. There is.

As the polyester used in the manufacture of containers, those using an antimony catalyst (hereinafter referred to as antimony catalyst polyester) and those using a germanium catalyst (hereinafter referred to as germanium catalyst polyester) are used as the synthetic catalyst thereof, and the cost is high. In this respect, antimony-catalyzed polyester is particularly widely used.

By the way, in recent years, for the purpose of reducing the environmental load, a container using polyester obtained by recycling a used polyester container by various methods (hereinafter referred to as recycled polyester) has been manufactured.

However, since the polyester container is not recycled for each catalyst used for polyester synthesis, there is an extremely high possibility that the recycled polyester contains an antimony catalyst. In addition, it is difficult to completely remove contaminants in the recycling of polyester containers.

Therefore, when the polyester container is repeatedly recycled, contaminants and antimony catalysts that could not be removed are accumulated, and there is a concern that they may be eluted into the contents.
Further, in convenience stores and the like, a container filled with contents is erected and heated in a hot warmer for sale. In such a heated state, the antimony elution is performed. This is especially problematic.

The present invention has been made in view of the above problems, and the problems to be solved are high hygiene and high hygiene in which elution of antimony and pollutants into the contents does not matter even in a heated state. It is to provide a multi-layer container having a high environmental load reduction property.
Another object of the present invention is to provide a multi-layer preform used for manufacturing this multi-layer container.

The multilayer container of the present invention includes a mouth portion, a shoulder portion, a body portion, and a bottom portion.
It has an inner layer and an outer layer,
The inner layer is composed of virgin polyester,
The outer layer is composed of recycled polyester,
The virgin polyester constituting the inner layer is one or more polyesters selected from manganese catalyst polyester, titanium catalyst polyester, aluminum catalyst polyester, lithium catalyst polyester and germanium catalyst polyester.
The inner layer is provided from the upper end to the bottom of the mouth.

In one embodiment, the multilayer container of the present invention has an eluted antimony concentration of less than 6 ppb.

In one embodiment, the content of the recycled polyester is 40 parts by mass or more and 95 parts by mass or less with respect to 100 parts by mass of the total amount of the resin material contained in the multilayer container.

In one embodiment, the thickness of the inner layer is 0.01 mm or more and 0.21 mm or less.

In one embodiment, the multilayer container of the present invention is a heating container.

The multi-layer preform of the present invention is a multi-layer preform for manufacturing the above-mentioned multi-layer container.
It has a mouth, a body, and a bottom,
It has an inner layer and an outer layer,
The inner layer is composed of virgin polyester,
The outer layer is composed of recycled polyester,
The virgin polyester constituting the inner layer is one or more polyesters selected from manganese catalyst polyester, titanium catalyst polyester, aluminum catalyst polyester, lithium catalyst polyester and germanium catalyst polyester.
The inner layer is provided from the upper end of the mouth portion to the lower end of the bottom portion.

According to the present invention, it is possible to provide a multi-layer container having high hygiene and high environmental load reduction. Further, it is possible to provide a multi-layer preform used for manufacturing this multi-layer container.
Further, in the multi-layer container of the present invention, the inner layer is made of virgin polyester and the outer layer is made of recycled polyester. However, in the container having a two-layer structure, it is relatively easy to adjust the thickness of each layer, and the outer layer can be used. The amount of recycled polyester used can be easily increased.

It is a schematic cross-sectional view which shows one Embodiment of the multilayer container of this invention. It is a schematic cross-sectional view which shows one Embodiment of the multilayer preform of this invention.

(Multi-layer container)
As shown in FIG. 1, the multilayer container 10 of the present invention has an inner layer 11 and an outer layer 12.
Further, the multilayer container 10 of the present invention may have a vapor deposition film on the surface of the inner layer 11 (not shown).

In one embodiment, the multilayer container 10 includes a mouth portion 13, a shoulder portion 14, a body portion 15, and a bottom portion 16. In one embodiment, the shoulder portion 14 is provided between the mouth portion 13 and the body portion 15, and has a shape in which the diameter gradually increases from the mouth portion 13 side to the body portion 15 side.

In one embodiment, as shown in FIG. 1, the mouth portion 13 includes a screw portion 17 to which a cap is screwed, a turnip 18 under the screw portion 17, and a support ring 19 under the turnip 18.
Further, in one embodiment, as shown in FIG. 1 and the like, the bottom portion 16 includes a recessed portion 20 located at the center and a ground contact portion 21 provided around the depressed portion 20. With such a configuration, it is possible to prevent deformation of the container due to an increase or decrease in the internal pressure when the heated contents are filled in the multilayer container or when the container is heated after filling.
Further, in one embodiment, the body portion 15 of the multilayer container 10 includes a panel portion 22. With such a configuration, it is possible to prevent deformation of the container due to an increase or decrease in the internal pressure when the heated contents are filled in the multilayer container or when the container is heated after filling.

The elution antimony concentration of the multilayer container of the present invention is preferably less than 6 ppb, and more preferably less than 3 ppb.
It is preferable that the elution antimony concentration is less than 6 ppb because it satisfies the value recommended by the US Food and Drug Administration (FDA) 21CFR (Federal Law Chapter 21).
Further, depending on the type of contents to be filled in the multilayer container of the present invention, a small amount of antimony may already be contained. By setting the elution antimony concentration of the multilayer container to less than 3 ppb, the antimony finally dissolved in the contents can be reduced.
In the present invention, the "eluted antimony concentration of the multi-layer container" is determined by filling the multi-layer container of the present invention with ultrapure water at 23 ° C. and allowing it to stand on its side for 14 days in an environment of 70 ° C. After that, the water taken out from the multi-layer container was measured.

The outer layer of the multilayer container of the present invention is made of recycled polyester as described later, and the content of the recycled polyester is 40 parts by mass or more and 95 parts by mass with respect to 100 parts by mass of the total amount of the resin material contained in the multilayer container. It is preferably 60 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less.
By setting the content of the recycled polyester to 40 parts by mass or more with respect to 100 parts by mass of the total amount of the resin material contained in the multi-layer container, the environmental load reduction property of the multi-layer container can be further improved.
By setting the content of the recycled polyester to 95 parts by mass or less with respect to 100 parts by mass of the total amount of the resin material contained in the multi-layer container, it is possible to prevent the recycled polyester from being exposed to the inner layer side in the production of the multi-layer container. Can be done.

The multi-layer container of the present invention preferably has a volume / weight of 5 mL / g or more and 50 mL / g or less, and more preferably 8 mL / g or more and 45 mL / g or less.
By setting the capacity / weight of the multi-layer container to 5 mL / g or more, the blow moldability of the multi-layer container can be improved.
Further, by setting the capacity / weight of the multilayer container to 50 mL / g or less, the heat resistance and strength of the multilayer container can be improved.

The multi-layer container of the present invention can prevent antimony and the like from elution into the contents even when the contents are filled with a high temperature and then heated after the contents are filled, and has high hygiene. Therefore, it can be suitably used as a heating container.

(Inner layer)
The inner layer of the multilayer container of the present invention is characterized by being composed of a virgin polyester selected from a manganese catalyst polyester, a titanium catalyst polyester, an aluminum catalyst polyester, a lithium catalyst polyester and a germanium catalyst polyester. With such a configuration, it is possible to prevent antimony elution into the contents even when recycled polyester is used for the outer layer.
In the present invention, the "virgin polyester" refers to the polyester which has not been recycled as described below, that is, an unused polyester.

Examples of the manganese catalyst include fatty acid manganese salts such as manganese acetate, manganese carbonate, manganese chloride, acetylacetonate salt of manganese, manganese hydroxide and the like. Examples of titanium catalysts include tetra-n-propyl titanate and tetra. By hydrolysis of titanium alkoxides such as -i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, etc. Obtained titanium oxide, titanium acetate, titanium oxalate, potassium titanium oxalate, sodium titanium oxalate, potassium titanate, sodium titanate, titanium acid-aluminum hydroxide mixture, titanium chloride, titanium chloride-aluminum chloride mixture, odor Examples thereof include titanium oxide, titanium fluoride, potassium tetrafluoride, cobalt hexafluoride, manganese hexafluoride, ammonium tetrafluoride and titanium acetylacetonate.
Examples of the aluminum catalyst include aluminum trisacetyl acetate, aluminum monoacetyl acetonate bis (ethyl acetoacetate) and ethyl acetoacetate aluminum diisopropylate.
Examples of the lithium catalyst include ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium and phenyllithium.
Examples of the germanium catalyst include germanium dioxide, germanium tetroxide, germanium tetramethoxyde, germanium tetraethoxydo, germanium tetrapropoxide, germanium tetrabutoxide, germanium tetrapentoxide and germanium tetrahexoxide.

In the present invention, "polyester" means a copolymer of a dicarboxylic acid compound and a diol compound.
Examples of the dicarboxylic acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecandioic acid, eicosandionic acid, pimelliic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, and adamantan. Dicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendandicarboxylic acid, anthracendicarboxylic acid, phenanthrangecarboxylic acid, 9,9'-bis Examples thereof include (4-carboxyphenyl) fluoric acid and ester derivatives thereof.
Examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. Diethanol, Decahydronaphthalenediethanol, Decahydronaphthalenediethanol, Norbornan diethanol, Norbornan diethanol, Tricyclodecanedimethanol, Tricyclodecaneethanol, Tetracyclododecanediethanol, Tetracyclododecanediethanol, Decalin diethanol, 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) Cyclohexylpropane), 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 the like.
Among the polyesters, polyethylene terephthalate, which is a copolymer of terephthalic acid and ethylene glycol, or modified polyethylene terephthalate to which a copolymerization monomer is added is preferable.

The polyester may contain a monomer other than the dicarboxylic acid compound and the diol compound as long as the characteristics of the present invention are not impaired, but the content thereof is preferably 10 mol% or less with respect to all the constituent units. It is more preferably 5 mol% or less, and further preferably 3 mol% or less.

As long as the characteristics of the present invention are not impaired, the inner layer may contain an additive, for example, an oxygen absorber, a gas barrier resin (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6), etc.). Polyamide), plasticizers, UV stabilizers, antioxidants, color inhibitors, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, thread friction reducing agents, slip agents, mold release agents, Examples include antioxidants, ion exchangers, acetaldehyde absorbers (eg, AA Plasticizers manufactured by Color Matrix) and colorants.

In the multilayer container 10 of the present invention, the inner layer 11 is provided from the upper end of the mouth portion 13 to the bottom portion 16 as shown in FIG.
With such a configuration, recycled polyester is used for the outer layer, and antimony elution into the contents is effective even when the product is stored in a heated state while being laid down sideways in a vending machine or the like. Can be prevented.

The thickness of the inner layer in the multilayer container is preferably 0.01 mm or more and 0.21 mm or less, and preferably 0.025 mm or more and 0.1 mm or less.
By setting the thickness of the inner layer of the multilayer container to 0.01 mm or more, it is possible to effectively prevent the elution of antimony into the contents even when recycled polyester is used for the outer layer.
Further, by setting the thickness of the inner layer in the multilayer container to 0.21 mm or less, the ratio of the outer layer in the multilayer container can be increased, and the environmental load reduction property of the multilayer container can be further improved.

(Outer layer)
The outer layer of the multilayer container of the present invention is made of recycled polyester. With such a configuration, the environmental load reduction property of the multilayer container of the present invention can be improved.

In the present invention, the "recycled polyester" refers to a chemical recycled polyester or a mechanical recycled polyester.
Chemically recycled polyester refers to polyester obtained by decomposing a polyester container to the monomer level and polymerizing it again.
Mechanical recycled polyester is a polyester container that is sorted, crushed, and washed to remove contaminants and foreign substances, and flakes are obtained. The flakes are further treated at high temperature and reduced pressure for a certain period of time to remove contaminants inside the resin. Refers to the polyester obtained by recycling.

As long as the characteristics of the present invention are not impaired, the outer layer may contain an additive, for example, an oxygen absorber, a gas barrier resin (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6), etc.). Polyamide), plasticizers, UV stabilizers, antioxidants, color inhibitors, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, thread friction reducing agents, slip agents, mold release agents, Examples include antioxidants, ion exchangers, acetaldehyde absorbers (eg, AA Plasticizers manufactured by Color Matrix) and colorants.

The thickness of the outer layer in the multilayer container is preferably 0.04 mm or more and 0.33 mm or less, and preferably 0.1 mm or more and 0.2 mm or less.
By setting the thickness of the outer layer of the multi-layer container to 0.04 mm or more, the environmental load reduction property of the multi-layer container can be further improved.
Further, by setting the thickness of the outer layer in the multilayer container to 0.33 mm or less, it is possible to prevent the recycled polyester from being exposed to the inner layer side in the production of the multilayer preform.

(Embedded film)
The multilayer container of the present invention may have a vapor-deposited film on the surface of the inner layer. Thereby, the gas barrier property of the multi-layer container can be improved.

Examples of the vapor deposition film include metals such as aluminum, inorganic oxides such as aluminum oxide, silicon oxide, magsium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide, and hexamethyldisiloxane. Examples thereof include a vapor-deposited film composed of a hard carbon film such as an organic silicon compound and a DLC (Diamond Like Carbon) film.
The hard carbon film made of a DLC film is a hard carbon film also called an i-carbon film or a hydrogenated amorphous carbon film (a-C: H), and is an amorphous carbon film mainly composed of SP3 bonds. is there.

The thickness of the thin-film deposition film is not particularly limited, and can be, for example, 1 nm or more and 150 nm or less.

The vapor deposition film can be formed by using a conventionally known method, for example, a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum vapor deposition method, a sputtering method and an ion plating method, and a plasma. Examples thereof include chemical vapor deposition methods (Chemical Vapor Deposition methods, CVD methods) such as chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition.

(Multi-layer preform)
The multilayer preform 23 of the present invention is used for manufacturing the multilayer container, and has an inner layer 24 and an outer layer 25 as shown in FIG.

In one embodiment, the multilayer preform 23 includes a mouth portion 26, a body portion 27, and a bottom portion 28, as shown in FIG.

(Inner layer)
Since the materials constituting the inner layer have been described above, the description thereof will be omitted here.

The thickness of the inner layer in the multilayer preform is preferably 0.1 mm or more and 1.2 mm or less, and preferably 0.2 mm or more and 0.5 mm or less.
By setting the thickness of the inner layer of the multilayer preform to 0.1 mm or more, it is possible to effectively prevent the elution of antimony into the contents even when recycled polyester is used for the outer layer.
By setting the thickness of the inner layer in the multilayer preform to 1.2 mm or less, the proportion of the outer layer in the multilayer container can be increased, and the environmental load reduction property of the multilayer container can be further improved.

(Outer layer)
Since the materials constituting the outer layer have been described above, the description thereof will be omitted here.

The thickness of the outer layer in the multilayer preform is preferably 1.2 mm or more and 3.5 mm or less, and preferably 1.9 mm or more and 2.2 mm or less.
By setting the thickness of the outer layer in the multi-layer preform to 1.2 mm or more, the environmental load reduction property of the multi-layer container can be further improved.
Further, by setting the thickness of the outer layer in the multilayer preform to 3.5 mm or less, it is possible to prevent the recycled polyester from being exposed to the inner layer side in the production of the multilayer preform.

(Manufacturing method of multi-layer container)
In the multi-layer container of the present invention, a multi-layer preform can be produced by co-injection molding the materials constituting the inner layer and the outer layer described above, and the multi-layer container of the present invention can be produced by blow molding the preform. ..

The multilayer container of the present invention can also be manufactured by utilizing two-color molding or insert molding.
Further, in the multi-layer container of the present invention, virgin polyester is injection-molded in the inner mold to form an inner layer, the inner mold is retracted, a gap is provided between the inner mold and the inner layer, and the gap is recycled. It can be produced by injection molding polyester to form an outer layer.

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

Example 1
Virgin polyester (germanium catalyst PET, manufactured by Mitsui Chemicals, Inc., J-125S) and mechanical recycled polyester (manufactured by Kyoei Sangyo Co., Ltd., NA-BT7906) were prepared.
These are co-injected using an injection molding machine to create a multi-layer (2 types, 2 layers) preform shown in FIG. 2, which includes an inner layer composed of virgin polyester and an outer layer composed of mechanically recycled polyester. did.
The amount of mechanically recycled policel used was adjusted to be 80 parts by mass with respect to 100 parts by mass of the resin material constituting the multilayer preform.
The thickness of the body of the multilayer preform was 2.8 mm, and the basis weight was 22 g.

Next, the multilayer preform was heated to 110 ° C. and biaxially stretched blow molding was performed in a blow molding die to obtain a multilayer container having an internal volume of 500 mL as shown in FIG.

Comparative Example 1
A single-layer preform was prepared in the same manner as in Example 1 except that only the mechanical recycled polyester was used, and this was biaxially stretch-blow molded to prepare a container having an internal volume of 500 mL.

Comparative Example 2
A single-layer preform was prepared in the same manner as in Example 1 except that only the virgin polyester was used, and this was biaxially stretched and blow-molded to prepare a container having an internal volume of 500 mL.

Comparative Example 3
A single-layer preform was prepared using only virgin polyester (antimony catalyst PET, manufactured by Shinko Synthetic Fiber, 5015W), and this was biaxially stretched and blow-molded to prepare a single-layer container having an internal volume of 500 mL.

<< Evaluation of Elution Antimony Concentration >>
The containers obtained in the above Examples and Comparative Examples were filled with 480 mL of ultrapure water. In each container, ultrapure water was filled from the position of 28.7 mm from the upper end of the mouth to the position of the bottom.
Then, in a hot warmer set at 70 ° C., the mixture was allowed to stand on its side for 14 days.
After standing, water was taken out from the container and its antimony concentration was measured by inductively coupled plasma mass spectrometry (ICP-MS). The measurement results are summarized in Table 1.

<< Heat resistance evaluation >>
The containers obtained in the above Examples and Comparative Examples were filled with 480 mL of water, capped, and then immersed in hot water at 70 ° C. for 80 minutes.
After the immersion, the container was erected on a flat desk and evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
OK: The container is upright.
NG: I didn't stand upright and fell down.

<< Environmental load reduction >>
Based on the content of recycled polyester with respect to the total amount of 100 parts by mass of the resin material contained in the containers obtained in the above Examples and Comparative Examples, the level of environmental load reduction was defined as follows.
OK: Recycled polyester content is 30 parts by mass or more NG: Recycled polyester content is less than 30 parts by mass

As is clear from the above table, it can be seen that the multi-layer container of the present invention has excellent environmental load reduction properties.
Further, it can be seen that the multilayer container of the present invention has high heat resistance and can effectively reduce the elution antimony concentration after heating, so that it can be suitably used for a heating container.

10: Multi-layer container, 11: Inner layer, 12: Outer layer, 13: Mouth, 14: Shoulder, 15: Body, 16: Bottom, 17: Screw, 18: Turnip, 19: Support ring, 20: Recess , 21: Grounding part, 22: Panel part, 23: Multi-layer preform, 24: Inner layer, 25: Outer layer, 26: Mouth part, 27: Body part, 28: Bottom part

Claims (6)

A multi-layer container having a mouth, shoulders, body, and bottom.
It has an inner layer and an outer layer,
The inner layer is made of virgin polyester.
The outer layer is made of recycled polyester.
The virgin polyester constituting the inner layer is one or more polyesters selected from manganese catalyst polyester, titanium catalyst polyester, aluminum catalyst polyester, lithium catalyst polyester and germanium catalyst polyester.
A multi-layer container characterized in that the inner layer is provided from the upper end of the mouth portion to the bottom portion. The multilayer container according to claim 1, wherein the elution antimony concentration is less than 6 ppb. The multilayer container according to claim 1 or 2, wherein the content of the recycled polyester is 40 parts by mass or more and 95 parts by mass or less with respect to 100 parts by mass of the total amount of the resin material contained in the multilayer container. The multilayer container according to any one of claims 1 to 3, wherein the inner layer has a thickness of 0.01 mm or more and 0.21 mm or less. The multi-layer container according to any one of claims 1 to 4, which is a heating container. A multi-layer preform for producing the multi-layer container according to any one of claims 1 to 5.
It has a mouth, a body, and a bottom,
It has an inner layer and an outer layer,
The inner layer is made of virgin polyester.
The outer layer is made of recycled polyester.
The virgin polyester constituting the inner layer is one or more polyesters selected from manganese catalyst polyester, titanium catalyst polyester, aluminum catalyst polyester, lithium catalyst polyester and germanium catalyst polyester.
A multi-layer preform characterized in that the inner layer is provided from the upper end of the mouth portion to the lower end of the bottom portion.