JP2022187891A - container and preform - Google Patents

Abstract

To provide a container excellent in reducing CO2 emission and suppressing a decrease in buckling strength and yellowing.SOLUTION: The present invention relates to a container containing polyester as a main component, wherein the polyester includes recycled polyester, virgin polyester, and polyester made of waste matter in a container manufacturing process, an inherent viscosity of the polyester made of the waste matter is lower than an inherent viscosity of the recycled polyester and the virgin polyester.SELECTED DRAWING: Figure 1

Description

The present invention relates to containers and preforms for the manufacture of such containers.

Conventionally, polyesters such as polyethylene terephthalate have been widely used in the manufacture of containers to be filled with beverages, etc., because they are excellent in mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency, etc., and are inexpensive. ing.

In recent years, in consideration of the environment, especially for the purpose of reducing _CO2 emissions, a method has been proposed in which polyester recovered from used PET bottles and other containers can be reused and recycled into containers as recycled polyester. It is For example, in Patent Document 1, in order to reduce the amount of CO ₂ emissions, it is proposed to use polyester, which is made by collecting and reusing used products formed using polyester, for containers. .

JP 2011-256328 A

The present inventors have now noticed that when only recycled polyester is used in a container, the buckling strength of the resulting container decreases and the container turns yellow (yellowing). The present inventors thought that by blending the container with virgin polyester, the decrease in buckling strength and yellowing described above could be suppressed.

However, in the container obtained as described above, although the decrease in buckling strength was suppressed, the suppression of yellowing was not sufficient. Moreover, the present inventors thought that yellowing could be suppressed by increasing the proportion of virgin polyester, but this would lead to the problem of worsening the ability to reduce CO ₂ emissions.

The present invention has been made in view of the above findings, and its object is to provide a container that is excellent in reducing CO ₂ emissions and suppresses a decrease in buckling strength and yellowing, and a method for manufacturing the container. It is to be.
Another object of the present invention is to provide a preform for manufacturing this container and a method for manufacturing the preform.

The present invention is a container containing polyester as a main component,
The polyester includes recycled polyester, virgin polyester, and polyester made from waste in the container manufacturing process,
In the container, the intrinsic viscosity of the waste polyester is lower than the intrinsic viscosity of the recycled polyester and the virgin polyester.

In the container according to the present invention, the intrinsic viscosity of the waste polyester may be 0.650 dL/g or more and 0.780 dL/g or less.

In the container according to the present invention, the intrinsic viscosity of the recycled polyester and the virgin polyester may be 0.750 dL/g or more and 0.870 dL/g or less.

In the container according to the present invention, the ratio of the mass of the virgin polyester to the total mass of the recycled polyester and the waste polyester may be 0.11 or more and 2.33 or less.

In the container according to the present invention, the ratio of the mass of the waste polyester to the total mass of the recycled polyester and the virgin polyester may be 0.001 or more and 0.111 or less.

In a container according to the invention, the volume to mass ratio may be greater than or equal to 5 mL/g and less than or equal to 50 mL/g.

A container according to the invention comprises a mouth, a neck, a shoulder, a body and a bottom,
A cross-sectional thickness of the trunk portion may be 0.05 mm or more and 0.54 mm or less.

The present invention is a preform for manufacturing the container.

The present invention provides a method for manufacturing the preform,
a step of dry-blending a pulverized material obtained by pulverizing waste in a manufacturing process of a container containing polyester as a main component, recycled polyester, and virgin polyester to obtain a mixture;
melting the mixture to obtain a melt;
a molding step of injecting the melt;
A method of manufacturing a preform, comprising:

In the preform manufacturing method according to the present invention, the recycled polyester and the virgin polyester may be in the form of pellets.

In the preform manufacturing method according to the present invention, the recycled polyester pellets may be formed by melting recycled polyester flakes.

In the preform manufacturing method according to the present invention, the recycled polyester may be in the form of flakes, and the virgin polyester may be in the form of pellets.

In the preform manufacturing method according to the present invention, the melting temperature may be 285° C. or higher and 300° C. or lower.

The present invention provides a method for manufacturing the container,
A method for manufacturing a container, comprising blow-molding the preform obtained by the method for manufacturing a preform.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the container excellent in _CO2 emission reduction property, and the fall of buckling strength and yellowing being suppressed can be provided.
According to the present invention, a preform for manufacturing this container and a method for manufacturing the preform can be provided.

1 is a schematic half-sectional view of one embodiment of a container according to the invention; FIG. 1 is a schematic half-sectional view showing one embodiment of a preform according to the invention; FIG.

[container]
As used herein, the term "container" means a molded body that accommodates an article. Examples of the container include molded articles such as compression molded articles, injection molded articles, blow molded articles and thermoformed articles. Examples of specific containers include bottles, vials, cups, trays and packs.

The container according to the invention contains polyester as a main component. The polyester includes recycled polyester, virgin polyester, and polyester made from waste in the container manufacturing process, and the intrinsic viscosity of the polyester made from the waste is lower than the intrinsic viscosity of the recycled polyester and the virgin polyester. It is.
As used herein, "recycled polyester" refers to polyester that is recycled by collecting products such as used containers that have been shipped to the market. Specifically, recycled polyester is produced by sorting, pulverizing, and washing used containers to remove contaminants and foreign substances to obtain flakes, which are further treated at high temperature and under reduced pressure for a certain period of time to contaminate the inside of the resin. It is a polyester obtained by removing substances and finally by solid state polymerization.
As used herein, "virgin polyester" refers to polyester that has not been recycled.
As used herein, the term "polyester made from waste in the container manufacturing process" refers to polyester obtained by collecting materials and defective products generated from the disposal route of the container manufacturing process. In addition, hereinafter, "polyester made from waste in the manufacturing process of containers" is also referred to as "pre-consumer polyester".

The container according to the present invention, having the above structure, is excellent in reducing CO ₂ emissions, and can suppress a decrease in buckling strength and yellowing. The reason is considered as follows.

First, the reason why the decrease in the buckling strength of the container can be suppressed will be described.
As described above, recycled polyester is polyester that is recycled by recovering products such as used containers that have been shipped to the market. A used container is also a container made from virgin polyester at the beginning of production. When manufacturing containers from polyester, there is at least the step of melting the polyester for injection molding. Therefore, when the recycled polyester is used to obtain a container, the recycled polyester has undergone at least two melting steps, the initial melting step and the melting step during recycling. Ester bonds present in polyesters are easily hydrolyzed, and hydrolysis is further accelerated under high temperature conditions. Every time the recycled polyester undergoes the melting process, the ester bond is hydrolyzed, resulting in the production of low-molecular-weight components such as monomers and oligomers. In general, recycled polyester undergoes solid phase polymerization to restore the reduced average molecular weight to its original state. Polyester contains more low molecular weight components than virgin polyester. As a result, it is considered that the buckling strength of the container is lowered.
In the container according to the present invention, the reduction in buckling strength can be suppressed by combining virgin polyester, which has not been subjected to heat history, with recycled polyester. A container having excellent buckling strength can be stacked in a larger number of cardboard boxes in which the container is packed, so that the storage efficiency in a warehouse is excellent.
In addition, the above-mentioned high-temperature condition is a treatment at a temperature at which the polyester is hydrolyzed in the air, and is not particularly limited, but is, for example, a treatment at a temperature of 230° C. or higher.

Next, the reason why yellowing of the container can be suppressed will be described.
As mentioned above, recycled polyester is solid phase polymerized, whereas pre-consumer polyester is polyester obtained by collecting materials and defective products generated from the disposal route of the product manufacturing process, so it is not recycled. Solid phase polymerization, such as in obtaining polyesters, has not been carried out. Therefore, the average molecular weight of pre-consumer polyester tends to be lower than that of virgin polyester and recycled polyester. As a result, the intrinsic viscosity (IV value) of pre-consumer polyester is lower than the IV value of virgin and recycled polyester. In the container manufacturing process, injection molding can be done at lower than normal temperatures if the IV value of the polyester is low. Thereby, the melting temperature of the polyester can be lowered.
The melting process for manufacturing a container is generally carried out in the atmosphere, and active gases such as oxygen in the atmosphere promote various decompositions or reactions other than the above hydrolysis, resulting in polyester yellowing may occur. The higher the temperature of the melting process, the more these decompositions or reactions proceed and the more yellowing of the polyester occurs.
By using pre-consumer polyester together with recycled polyester and virgin polyester, the container according to the present invention can be injection molded at a melting temperature lower than usual in the container manufacturing process, so it is thought that yellowing of the container can be suppressed. be done. A container with suppressed yellowing can be suitably used, for example, as a container filled with a colorless and transparent content such as water.
Moreover, since pre-consumer polyester is originally discarded, production costs can be suppressed by using it.

As used herein, "main component" means a component that accounts for more than 50% by mass of the total. The polyester content in the container is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 99% by mass or more.

As used herein, "polyester" means a polymer polymerized by ester bonds. Such polyesters are usually obtained by polycondensation of a dicarboxylic acid compound and a diol compound.
Dicarboxylic acid compounds include, for example, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, adamantane dicarboxylic acid, norbornene dicarboxylic acid, cyclohexanedicarboxylic acid, decalinedicarboxylic 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-sodiumsulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthenedicarboxylic acid, 9,9'-bis (4-Carboxyphenyl)fluoric acid and their ester derivatives.
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, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanedimethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindimethanol, decalindiethanol, 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 bis-β-hydroxyethyl terephthalate (BHET).
The polyester is preferably polyethylene terephthalate or modified polyethylene terephthalate obtained by polymerizing a raw material monomer for polyethylene terephthalate and a copolymerization monomer.

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

The polyester may be polymerized using a polymerization catalyst. Polymerization catalysts include manganese catalysts, titanium catalysts, aluminum catalysts, lithium catalysts, germanium catalysts, antimony catalysts, and the like.

In the container according to the present invention, the ratio of the weight of virgin polyester to the total weight of recycled polyester and pre-consumer polyester is preferably 0.11 or more and 2.33 or less, more preferably 0.5 or more and 1.5 or less. .
A decrease in the buckling strength of the container can be further suppressed by setting the mass ratio to 0.11 or more.
By setting the mass ratio to 2.33 or less, the CO ₂ emission reduction property of the container can be further improved.

In the container according to the present invention, the ratio of the mass of pre-consumer polyester to the total mass of recycled polyester and virgin polyester is preferably 0.001 or more and 0.111 or less, more preferably 0.01 or more and 0.1 or less. , more preferably 0.05 or more and 0.08 or less.
By setting the mass ratio to 0.001 or more, the melting temperature of the polyester during injection molding can be lowered, and yellowing of the container can be further suppressed.
By setting the mass ratio to 0.111 or less, an excessive decrease in the IV value of the polyester can be suppressed, and the moldability and impact strength of the container can be improved.

In the container according to the present invention, the total content of recycled polyester, virgin polyester and pre-consumer polyester is preferably more than 50% by weight, more preferably 70% by weight or more, and even more preferably, based on the total weight of the container. is 90% by mass or more, and more preferably 99% by mass or more.

In the range satisfying the requirement that the IV value of the pre-consumer polyester is lower than the IV value of the recycled polyester and the virgin polyester, the IV value of the pre-consumer polyester contained in the container according to the present invention is preferably 0.650 dL/g or more. 780 dL/g or less, more preferably 0.720 dL/g or more and 0.765 dL/g or less.
By setting the IV value to 0.650 dL/g or more, the moldability and impact strength of the container can be improved.
By setting the IV value to 0.780 dL/g or less, the melting temperature of the polyester during injection molding can be lowered, and yellowing of the container can be further suppressed.

To the extent that the IV value of the pre-consumer polyester is lower than the IV value of the recycled polyester and the virgin polyester, the IV value of the recycled polyester and the virgin polyester contained in the container according to the present invention is preferably 0.750 dL/g. It is 0.870 dL/g or more and more preferably 0.770 dL/g or more and 0.820 dL/g or less.
By setting the IV value to 0.750 dL/g or more, the moldability and impact strength of the container can be improved.
By setting the IV value to 0.870 dL/g or less, the melting temperature of the polyester during injection molding can be lowered, and yellowing of the container can be further suppressed.

The container may contain additives as long as they do not impair the characteristics of the present invention, such as oxygen absorbers, gas barrier resins (nylon 6, nylon 6,6 and polymetaxylylene adipamide (MXD6)). polyamide), plasticizers, UV stabilizers, antioxidants, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, thread friction reducing agents, slip agents, release agents, Antioxidants, ion exchange agents, acetaldehyde absorbents (eg, AA Scavengers from Color Matrix) and coloring agents are included.

An embodiment of the container structure according to the present invention will now be described with reference to FIG.

FIG. 1 is a schematic half-sectional view showing one embodiment of a container 10 according to the present invention. The container 10 includes a mouth portion 11, a neck portion 12, a shoulder portion 13, a body portion 14, and a bottom portion 15, as shown in FIG.

In one embodiment, the spout 11 comprises a threaded portion 16 to which the cap is screwed, a turnip 17 below the threaded portion 16, and a support ring 18 below the turnip 17, as shown in FIG.

In one embodiment, neck 12 is located between support ring 18 and shoulder 13 and has a generally cylindrical shape with a generally uniform diameter, as shown in FIG. Moreover, in one embodiment, the shoulder portion 13 has a cylindrical shape whose diameter gradually increases from the neck portion 12 side toward the body portion 14 side.

In one embodiment, body 14 is located between shoulder 13 and bottom 15, as shown in FIG. In one embodiment, the body 14 also includes a panel portion 21 into which the body 14 is recessed, as shown in FIG. With such a configuration, deformation of the container due to increase/decrease in internal pressure can be prevented when the container is filled with heated contents or when the container is heated after being filled with the contents.
In addition, since the container according to the present invention suppresses a decrease in buckling strength, the shape of the body can be appropriately selected. That is, it is no longer necessary to form the body of the container into a shape suitable for buckling strength, and various shapes can be selected.

In one embodiment, as shown in FIG. 1, the bottom portion 15 includes a centrally-located recessed portion 19 and a ground portion 20 provided around the recessed portion 19. At this ground portion 20, the trunk portion 14 are connected. With such a configuration, deformation of the container due to an increase or decrease in internal pressure can be prevented when the container is filled with heated contents or polyester is heated after being filled with the contents.
In one embodiment, the "bottom part" means the inner part from the ground part when the container is made to stand on its own.

Since the container according to the present invention has a suppressed reduction in buckling strength, it is possible to maintain a high volume-to-mass ratio (volume/mass). As a result, it is possible to prevent the polyester from being used in an excessive amount and to reduce the amount of the polyester to be discarded, thereby improving the environmental load reduction and improving the blow moldability of the container.
The volume/mass is preferably 5 mL/g or more and 50 mL/g or less, more preferably 8 mL/g or more and 50 mL/g or less.

In the container according to the present invention, the reduction in buckling strength is suppressed, so the thickness of the container can be reduced. As a result, it is possible to prevent the polyester from being used in an excessive amount and to reduce the amount of the polyester to be discarded, thereby improving the environmental load reduction and improving the blow moldability of the container.
The cross-sectional thickness of the body of the container is preferably 0.05 mm or more and 0.54 mm or less, more preferably 0.05 mm or more and 0.5 mm or less.
The thickness means the thinnest portion of the cross section.

A container according to the present invention may have a single-layer structure or a multilayer structure of two or more layers. Moreover, when the container has a multilayer structure, each layer may have the same composition or different compositions.

In one embodiment, the container may have a deposited film on its surface. Thereby, the gas barrier properties of the container can be improved.

Examples of deposited films include metals such as aluminum, inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide, hexamethyldisiloxane, and the like. organic silicon compounds, and a hard carbon film such as a DLC (Diamond Like Carbon) film.
A 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 (aC:H) ^, and is an amorphous carbon film mainly composed of SP3 bonds. is.

Also, the thickness of the deposited film is not particularly limited, and can be, for example, 1 nm or more and 150 nm or less.

Formation of the deposited film can be performed using a conventionally known method, for example, a physical vapor deposition method (physical vapor deposition method, PVD method) such as a vacuum deposition method, a sputtering method and an ion plating method, and a plasma A chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as a chemical vapor deposition method, a thermal chemical vapor deposition method, and a photochemical vapor deposition method can be used.
In addition, the thickness of the deposited layer can be measured, for example, at the body of the container, and means the point where the thickness is the thinnest.

[Container manufacturing method]
A container according to the present invention can be manufactured by blow molding a preform described later. Blow molding can be performed by a conventionally known method.

[preform]
As used herein, a preform is a preform prior to blow molding of a container. The preform according to the invention is used for manufacturing the container according to the invention. Therefore, the preform according to the present invention contains polyester as a main component, and the polyester includes recycled polyester, virgin polyester, and pre-consumer polyester, and the intrinsic viscosity of the pre-consumer polyester is the same as that of the recycled polyester and the virgin polyester. It is lower than the intrinsic viscosity. The container according to the present invention can be manufactured by configuring the preform in this way.
Incidentally, the polyester contained in the preform according to the present invention can be the same as that used for the container according to the present invention.

An embodiment of the structure of the preform according to the invention will now be described with reference to FIG.

FIG. 2 is a schematic half-sectional view showing one embodiment of the preform according to the present invention. The preform 30 includes a mouth portion 31 , a body portion 32 connected to the mouth portion 31 , and a bottom portion 33 connected to the body portion 32 as shown in FIG. Of these, the mouth portion 31 corresponds to the mouth portion 11 of the container 10 and has substantially the same shape as the mouth portion 11 . The body portion 32 corresponds to the neck portion 12, the shoulder portion 13 and the body portion 14 of the container 10, and has a substantially cylindrical shape. The bottom portion 33 corresponds to the bottom portion 15 of the container 10 and has a substantially hemispherical shape.

The mouth portion 31 includes a screw portion 34 corresponding to the screw portion 16 of the container 10 to which a cap (not shown) is screwed, a cover 35 provided below the screw portion 34 and corresponding to the cover 17 of the container 10 , and a cover 35 . , and has a support ring 36 corresponding to the support ring 18 of the container 10 . The shape of the mouth portion 31 may be a conventionally known shape.

The cross-sectional thickness of the preform according to the present invention is preferably 1.3 mm or more and 4.7 mm or less, more preferably 2.1 mm or more and 4.0 mm or less. By setting the thickness of the cross section within the above range, the container according to the present invention can be manufactured.
The thickness of the cross section of the preform can be measured, for example, at the body portion of the preform, and means the point where the thickness of the cross section is the thinnest.

[Preform manufacturing method]
The method for producing a preform according to the present invention comprises a process for producing a container containing polyester as a main component, and a pulverized product obtained by pulverizing waste (hereinafter also simply referred to as “pulverized product”), recycled polyester, and virgin polyester. It includes the steps of blending to obtain a mixture, melting the mixture to obtain a melt, and molding the melt by injecting it. The shape of the pulverized product is not particularly limited, but examples thereof include spherical, polyhedral, needle-like and columnar shapes.
In addition, in the preform manufacturing method according to the present invention, the same recycled polyester and virgin polyester as used in the container according to the present invention can be used.

In the preform manufacturing method according to the present invention, the pulverized material, the recycled polyester, and the virgin polyester are previously dry-blended before being melted. By adopting such a process, it is possible to manufacture a container in which the pulverized material, the recycled polyester and the virgin polyester are uniformly dispersed.

In the preform manufacturing method according to the present invention, the mixing ratio of virgin polyester to recycled polyester and pulverized material is preferably 0.11 or more and 2.33 or less, more preferably 0.5 or more and 1.5 or less.

In the preform manufacturing method according to the present invention, the mixing ratio of the pulverized material to the recycled polyester and virgin polyester is preferably 0.001 or more and 0.111 or less, more preferably 0.01 or more and 0.1 or less, It is more preferably 0.05 or more and 0.08 or less.

In one embodiment, the recycled polyester and virgin polyester may be in the form of pellets or flakes. When the recycled polyester is in the form of pellets, the pellets may be formed by melting recycled polyester flakes.
In another embodiment, the recycled polyester may be in the form of flakes and the virgin polyester in the form of pellets.

In the preform manufacturing method according to the present invention, the mixture can be melted by a conventionally known method, and the melting temperature is preferably 285° C. or higher and 300° C. or lower. By setting the melting temperature within this range, the pulverized material and the recycled polyester can be melted, and the container can be prevented from turning yellow. The melting temperature is more preferably 285°C or higher and 295°C or lower.
In addition, in this specification, "melting temperature" refers to the temperature of melted polyester.

In the preform manufacturing method according to the present invention, the step of injection molding the melt can be performed by a conventionally known method.

EXAMPLES 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]
A flaky recycled polyester, a pellet-shaped virgin polyester (manufactured by Shinko Synthetic Fiber Co., Ltd., 5015W), and pulverized pre-consumer polyester were prepared.
First, flake-like polyester was melted to obtain pellet-like recycled polyester. 45 parts by mass of recycled polyester pellets, 50 parts by mass of virgin polyester pellets, and 5 parts by mass of pulverized pre-consumer polyester were dry-blended. The resulting mixture was melted at 295° C. and the melt was injected using an injection molding machine to produce a preform shown in FIG.
The thickness of the body of the preform was 3.5 mm, and the basis weight was 21 g.

Next, the preform was heated to 110° C. and biaxially stretched blow-molded in a blow-molding mold to produce a container with an internal capacity of 500 mL as shown in FIG. The cross-sectional thickness at the body of the container was 0.32 mm. The volume/mass ratio of the polyester composing the container was 23.8.

[Example 2]
65 parts by mass of the recycled polyester pellets, 30 parts by mass of the virgin polyester pellets, and 5 parts by mass of the pulverized pre-consumer polyester were dry-blended to obtain a mixture except that Example 1 A preform was produced in the same manner as

Then, in the same manner as in Example 1, a container was produced from the above preform.

[Example 3]
45 parts by mass of the recycled polyester flakes, 50 parts by mass of the virgin polyester pellets, and 5 parts by mass of the pulverized pre-consumer polyester were dry blended to obtain a mixture except that Example 1 A preform was produced in the same manner as

Then, in the same manner as in Example 1, a container was produced from the above preform.

[Example 4]
65 parts by mass of the post-consumer recycled polyester flakes, 30 parts by mass of the virgin polyester pellets, and 5 parts by mass of the pre-consumer pulverized polyester were dry blended to obtain a mixture, except that a mixture was obtained. A preform was produced in the same manner as in Example 1.

Then, in the same manner as in Example 1, a container was produced from the above preform.

[Comparative Example 1]
A preform was produced in the same manner as in Example 1, except that only the recycled polyester pellets were used and the melting temperature was set to 305°C.

Then, in the same manner as in Example 1, a container was produced from the above preform.

[Comparative Example 2]
A preform was produced in the same manner as in Example 1 except that only pellets of the virgin polyester were used and the melting temperature was set to 305°C.

Then, in the same manner as in Example 1, a container was produced from the above preform.

[Comparative Example 3]
A preform was produced in the same manner as in Example 1 except that only 50 parts by mass of the recycled polyester pellets and 50 parts by mass of the virgin polyester pellets were used and the melting temperature was set to 305°C.

Then, in the same manner as in Example 1, a container was produced from the above preform.

[Comparative Example 4]
A preform was produced in the same manner as in Example 1 except that only 70 parts by mass of the recycled polyester pellets and 30 parts by mass of the virgin polyester pellets were used and the melting temperature was set to 305°C.

Then, in the same manner as in Example 1, a container was produced from the above preform.

<<Content of virgin polyester>>
Table 1 shows the virgin polyester content of the containers produced in the above Examples and Comparative Examples.

<<Measurement of buckling strength>>
After filling 500 ml of the content liquid (water) into each of the containers produced in the above examples and comparative examples, the containers were sealed with caps. A buckling strength test was performed on each container in an upright state. A top load tester (buckling tester) EH-1000 manufactured by Evic Co., Ltd. was used to measure the buckling strength. A load was applied from the top of the mouth at a constant rate, and the maximum load at which a so-called yield state occurred was taken as the buckling strength. Table 1 shows the measurement results.

<<Measurement of color>>
A sample obtained by finely cutting only the mouth portion of the polyester container produced in the above Examples and Comparative Examples was precooled under liquid nitrogen for 10 minutes using a freeze crusher (manufactured by SPEX, Model 6870 Freezer/Mill). A powder was obtained by freeze-milling for 10 minutes under nitrogen. Then, this powder is measured with reflected light using a spectral colorimeter (CMS-35SP, manufactured by Murakami Color Research Laboratory Co., Ltd.) to determine the L ^* value and a ^* value in the L ^* a ^* b ^* color system. and b ^* values were measured. The measurement conditions were SCE (exclude specular reflection), 10° field of view, and D65 light source. In addition, the measurement was performed based on JISZ8722:2009. Table 1 shows the measurement results.

The containers of Examples 1-4 are superior in reducing CO ₂ emissions compared to the container of Comparative Example 2, which uses only virgin polyester.
The containers of Examples 1 to 4 exhibit less reduction in buckling strength than the container of Comparative Example 1, which uses only recycled polyester.
Compared with the container of Comparative Example 3, which uses only recycled polyester and virgin polyester, the containers of Examples 1 and 3 have a smaller b ^* value, which indicates yellowness, and thus yellowing is suppressed. In addition, the containers of Examples 2 and 4 have a smaller b ^* value representing yellowness than the container of Comparative Example 4, which uses only recycled polyester and virgin polyester, and thus yellowing is suppressed.

10: Container 11: Mouth 12: Neck 13: Shoulder 14: Body 15: Bottom 16: Screw 17: Turnip 18: Support ring 19: Depression 20: Ground 21: Panel 30: Preform 31: Mouth 32: Body 33: Bottom 34: Screw 35: Turnip 36: Support ring

Claims (14)

A container containing polyester as a main component,
The polyester includes recycled polyester, virgin polyester, and polyester made from waste in the container manufacturing process,
The container, wherein the intrinsic viscosity of the waste polyester is lower than the intrinsic viscosity of the recycled polyester and the virgin polyester. 2. The container according to claim 1, wherein the intrinsic viscosity of the waste polyester is 0.650 dL/g or more and 0.780 dL/g or less. The container according to claim 1 or 2, wherein the recycled polyester and the virgin polyester have intrinsic viscosities of 0.750 dL/g or more and 0.870 dL/g or less. The container according to any one of claims 1 to 3, wherein the ratio of the mass of the virgin polyester to the total mass of the recycled polyester and the waste polyester is 0.11 or more and 2.33 or less. The container according to any one of claims 1 to 4, wherein the ratio of the mass of the polyester made from waste to the total mass of the recycled polyester and the virgin polyester is 0.001 or more and 0.111 or less. The container according to any one of claims 1 to 5, wherein the volume to mass ratio is 5 mL/g or more and 50 mL/g or less. comprising a mouth, a neck, a shoulder, a body and a bottom,
The container according to any one of claims 1 to 6, wherein the body has a cross-sectional thickness of 0.05 mm or more and 0.54 mm or less. A preform for manufacturing a container according to any one of claims 1 to 7. A method for manufacturing a preform according to claim 8,
a step of dry-blending a pulverized material obtained by pulverizing waste in a manufacturing process of a container containing polyester as a main component, recycled polyester, and virgin polyester to obtain a mixture;
melting the mixture to obtain a melt;
a molding step of injecting the melt;
A method of manufacturing a preform, comprising: 10. The method of manufacturing a preform according to claim 9, wherein the recycled polyester and the virgin polyester are in the form of pellets. 11. The method of manufacturing a preform according to claim 10, wherein the recycled polyester pellets are formed by melting recycled polyester flakes. 10. The method of manufacturing a preform according to claim 9, wherein the recycled polyester is in the form of flakes and the virgin polyester is in the form of pellets. The method for manufacturing a preform according to any one of claims 9 to 12, wherein the melting temperature is 285°C or higher and 300°C or lower. A method for manufacturing a container according to any one of claims 1 to 7,
A method for manufacturing a container, comprising a step of blow molding a preform obtained by the method for manufacturing a preform according to any one of claims 9 to 13.

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