Container and preform

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

Technical Field

[0001] The present invention relates to a container and a preform for manufacturing the container.

Background Art

[0002] Conventionally, polyesters such as polyethylene terephthalate have been widely used in the manufacture of containers for filling beverages and the like because they are excellent in mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency, and are inexpensive.

[0003] In recent years, for the purpose of considering the environment, particularly reducing CO2 emissions, a method has been proposed to recycle polyester recovered from used containers such as PET bottles so that it can be reused and recycled again as recycled polyester for containers. For example, in Patent Document 1, in order to reduce the amount of CO2 emissions, it has been proposed to use a polyester that allows used products formed of polyester to be recovered and reused again for containers.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Recently, the present inventors have noticed that when only recycled polyester is used for a container, the buckling strength of the obtained container decreases and the container turns yellow (yellowing). The present inventors considered that by blending virgin polyester with the container, the above-described decrease in buckling strength and yellowing can be suppressed.

[0006] However, although the reduction in buckling strength was suppressed in the container obtained as described above, the suppression of yellowing was not sufficient. Further, the inventors thought that yellowing could be suppressed by increasing the proportion of virgin polyester, but this time, a problem occurred in that the CO2 emission reduction property deteriorated.

[0007] The present invention has been made in view of the above findings, and an object thereof is to provide a container excellent in CO2 emission reduction property and having a reduced buckling strength and suppressed yellowing, and a method for manufacturing the container. Another object of the present invention is to provide a preform for manufacturing this container and a method for manufacturing the preform.

Means for Solving the Problems

[0008] The present invention is a container containing polyester as a main component, wherein the polyester includes recycled polyester, virgin polyester, and polyester made from waste in the container manufacturing process, and the container is such that the intrinsic viscosity of the polyester made from the waste is lower than the intrinsic viscosities of the recycled polyester and the virgin polyester.

[0009] In the container according to the present invention, the intrinsic viscosity of the polyester made from the waste may be 0.650 dL / g or more and 0.780 dL / g or less.

[0010] In the container according to the present invention, the intrinsic viscosities of the recycled polyester and the virgin polyester may be 0.750 dL / g or more and 0.870 dL / g or less.

[0011] 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 polyester made from the waste may be 0.11 or more and 2.33 or less.

[0012] In the container according to the present invention, the ratio of the mass of the polyester made of the waste to the total mass of the recycled polyester and the virgin polyester may be 0.001 or more and 0.111 or less.

[0013] In the container according to the present invention, the ratio of volume to mass may be 5 mL / g or more and 50 mL / g or less.

[0014] The container according to the present invention includes a mouth part, a neck part, a shoulder part, a body part, and a bottom part. The thickness of the cross section in the body part may be 0.05 mm or more and 0.54 mm or less.

[0015] The present invention is a preform for manufacturing the container.

[0016] The present invention is a method for manufacturing the preform, a step of obtaining a mixture by dry-blending a pulverized product obtained by pulverizing waste in a manufacturing process of a container containing polyester as a main component, recycled polyester, and virgin polyester; a step of melting the mixture to obtain a melt; a step of injection molding the melt; and includes a method for manufacturing a preform.

[0017] In the method for manufacturing a preform according to the present invention, the forms of the recycled polyester and the virgin polyester may be pellets.

[0018] In the method for manufacturing a preform according to the present invention, the pellets of the recycled polyester may be formed by melting flakes of the recycled polyester.

[0019] In the method for manufacturing a preform according to the present invention, the form of the recycled polyester is flakes, and the form of the virgin polyester may be pellets.

[0020] In the method for manufacturing a preform according to the present invention, the temperature of the melting may be 285°C or higher and 300°C or lower.

[0021] The present invention is a method for manufacturing the container, which includes a step of blow molding a preform obtained by the method for manufacturing the preform.

Advantages of the Invention

[0022] According to the present invention, it is possible to provide a container excellent in CO2 emission reduction properties and having suppression of a decrease in buckling strength and yellowing, and a method for manufacturing the container. According to the present invention, it is possible to provide a preform for manufacturing this container and a method for manufacturing the preform.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0024] [Container] In this specification, the container means a molded body for accommodating an article. Examples of the container include molded bodies such as compression molded bodies, injection molded bodies, blow molded bodies, and thermoformed bodies. Specific examples of the container include bottles, vial bottles, cups, trays, and packs.

[0025] The container according to the present invention contains a 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 viscosities of the recycled polyester and the virgin polyester. As used herein, the term "recycled polyester" refers to polyester recycled from products such as used containers shipped to the market. Specifically, recycled polyester is obtained by sorting, pulverizing, and washing used containers to remove contaminants and foreign substances, obtaining flakes, further treating the flakes under high temperature and reduced pressure for a certain period of time to remove contaminants inside the resin, and finally subjecting the flakes to solid-phase polymerization. As used herein, the term "virgin polyester" refers to polyester that has not been recycled as described above. 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 waste route in the container manufacturing process. In the following, "polyester made from waste in the container manufacturing process" is also referred to as "pre-consumer polyester".

[0026] By adopting the above configuration, the container according to the present invention is excellent in CO2 emission reduction and can suppress a decrease in buckling strength and yellowing. The reason is considered as follows.

[0027] First, the reason for suppressing a decrease in the buckling strength of the container will be described. Recycled polyester is, as described above, polyester that has been recycled by collecting products such as used containers shipped to the market. Used containers were also containers manufactured from virgin polyester at the beginning of production. When manufacturing a container from polyester, there is at least a step of melting the polyester in order to perform injection molding. Therefore, when obtaining a container using recycled polyester, this recycled polyester has undergone at least two melting steps: the melting step at the beginning of production and the melting step during recycling. The ester bonds present in polyester are easily hydrolyzed, and hydrolysis is further promoted under high-temperature conditions. Each time recycled polyester undergoes a melting step, the ester bonds are hydrolyzed, and as a result, low-molecular-weight components such as monomers and oligomers are generated. Generally, recycled polyester undergoes solid-phase polymerization to return the reduced average molecular weight to its original state. However, since the generated low-molecular-weight components have a relatively stable structure, their proportion is difficult to decrease. Therefore, recycled polyester contains more low-molecular-weight components than virgin polyester. As a result, it is considered that the buckling strength of the container decreases. The container according to the present invention can suppress a decrease in buckling strength by combining virgin polyester that has not received a heat history with recycled polyester. A container having excellent buckling strength, for example, can stack more cardboard boxes packed with the container, and thus has excellent storage efficiency in a warehouse. The above high-temperature conditions are treatments at a temperature at which polyester is hydrolyzed in the atmosphere and are not particularly limited. For example, they are treatments at a temperature of 230°C or higher.

[0028] Next, the reason for suppressing yellowing of the container will be explained. As described above, the recycled polyester is solid-phase polymerized. Since the pre-consumer polyester is a polyester obtained by collecting materials generated from the waste route in the process of manufacturing the product and defective products, solid-phase polymerization like that for obtaining recycled polyester is not carried out. Therefore, the average molecular weight of the pre-consumer polyester tends to be lower than that of virgin polyester and recycled polyester. As a result, the intrinsic viscosity (IV value) of the pre-consumer polyester is lower than the IV values of virgin polyester and recycled polyester. In the manufacturing process of the container, injection molding can be carried out at a lower temperature than usual when the IV value of the polyester is low. Thereby, the melting temperature of the polyester can be lowered. The melting process when manufacturing the container is generally carried out in the atmosphere. However, due to active gases such as oxygen in the atmosphere, various decompositions or reactions proceed in addition to the above hydrolysis, and as a result, yellowing may occur in the polyester. The higher the temperature of the melting process, the further these decompositions or reactions proceed, and the more yellowing of the polyester occurs. The container according to the present invention uses pre-consumer polyester together with recycled polyester and virgin polyester. Therefore, in the manufacturing process of the container, the polyester can be injection-molded at a lower melting temperature than usual, and it is considered that yellowing of the container can be suppressed. The container with suppressed yellowing can be suitably used, for example, for a container filled with a colorless and transparent content such as water. In addition, since the pre-consumer polyester is originally to be discarded, using it can suppress the production cost.

[0029] In this specification, "main component" means a component exceeding 50% by mass of the whole. The content of polyester 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.

[0030] As used herein, "polyester" means a polymer polymerized by an ester bond. Such a polyester is usually obtained by polycondensing 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, dodecanedioic acid, eicosanedioic acid, pimelic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, adamantane dicarboxylic acid, norbornene dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic 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'-diphenylether dicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendendicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, 9,9'-bis(4-carboxyphenyl)fluorene 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, cyclohexanedietanol, decahydronaphthalenedimethanol, decahydronaphthalenedietanol, norbornanedimethanol, norbornanedietanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanedietanol, decalindimethanol, decalindietanol, 5-methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxycyclohexyl)propane, 2,2-bis(4-(2-hydroxyethoxy)cyclohexyl)propane, cyclopentanediol, 3-methyl-1,2-cyclopentanediol, 4-cyclopentene-1,3-diol, adamandiols, paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, pentaerythritol, and bis-β-hydroxyethyl terephthalate (BHET), etc. The polyester is preferably polyethylene terephthalate, or a modified polyethylene terephthalate obtained by polymerizing a raw material monomer of polyethylene terephthalate and a copolymerization monomer.

[0031] Within the range not impairing the characteristics of the present invention, the polyester may contain monomers other than the dicarboxylic acid compound and the diol compound, but the content thereof is preferably 10 mol% or less, more preferably 5 mol% or less, and still more preferably 3 mol% or less based on all the constituent units.

[0032] The polyester may be polymerized using a polymerization catalyst. Examples of the polymerization catalyst include manganese catalysts, titanium catalysts, aluminum catalysts, lithium catalysts, germanium catalysts, antimony catalysts, etc.

[0033] In the container according to the present invention, the ratio of the mass of virgin polyester to the total mass 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. By setting the mass ratio to 0.11 or more, a decrease in the buckling strength of the container can be further suppressed. By setting the mass ratio to 2.33 or less, the CO2 emission reduction property of the container can be further improved.

[0034] 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, still 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, a decrease in the excessive IV value of the polyester is suppressed, and the moldability and impact strength of the container can be improved.

[0035] 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 mass, more preferably 70% by mass or more, still more preferably 90% by mass or more, and even more preferably 99% by mass or more with respect to the total mass of the container.

[0036] In the range satisfying the requirement that the IV value of the pre-consumer polyester is lower than the IV values 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 and 0.780 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.

[0037] In a range satisfying the requirement that the IV value of the pre-consumer polyester is lower than the IV values of the recycled polyester and virgin polyester, the IV values of the recycled polyester and virgin polyester contained in the container according to the present invention are preferably 0.750 dL / g or more and 0.870 dL / g or less, 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.

[0038] Within a range that does not impair the characteristics of the present invention, the container may contain additives, for example, oxygen absorbers, gas barrier resins (polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6)), plasticizers, ultraviolet stabilizers, antioxidants, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, yarn friction reducers, slip agents, mold release agents, antioxidants, ion exchangers, acetaldehyde absorbers (for example, AA Scavengers manufactured by Color Matrix), and coloring agents.

[0039] Hereinafter, with reference to FIG. 1, an embodiment of the structure of the container according to the present invention will be described.

[0040] FIG. 1 is a schematic half-sectional view showing an embodiment of the container 10 according to the present invention. As shown in FIG. 1, 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.

[0041] In one embodiment, as shown in FIG. 1, the mouth portion 11 includes a screw portion 16 to which a cap is screwed, a flange 17 below the screw portion 16, and a support ring 18 below the flange 17.

[0042] In one embodiment, as shown in FIG. 1, the neck portion 12 is located between the support ring 18 and the shoulder portion 13, and has a substantially cylindrical shape with a substantially uniform diameter. Further, in one embodiment, the shoulder portion 13 has a cylindrical shape in which the diameter gradually increases from the neck portion 12 side toward the body portion 14 side.

[0043] In one embodiment, as shown in FIG. 1, the body portion 14 is located between the shoulder portion 13 and the bottom portion 15. Further, in one embodiment, as shown in FIG. 1, the body portion 14 includes a panel portion 21 in which the body portion 14 is recessed inward. By adopting such a configuration, when filling the container with heated contents or in the case of a container that is heated after filling the contents, it is possible to prevent the container from deforming due to changes in internal pressure. Note that since the reduction in buckling strength of the container according to the present invention is suppressed, the shape of the body portion can be appropriately selected. That is, it is not necessary to make the body portion of the container have a shape suitable for the buckling strength, and various shapes can be selected.

[0044] In one embodiment, as shown in FIG. 1, the bottom portion 15 includes a recessed portion 19 located at the center and a grounding portion 20 provided around the recessed portion 19, and is connected to the body portion 14 at the grounding portion 20. By adopting such a configuration, when filling the container with heated contents or in the case of a polyester that is heated after filling the contents, it is possible to prevent the container from deforming due to changes in internal pressure. Note that in one embodiment, the "bottom portion" means the inner portion from the grounding portion when the container is made to stand on its own.

[0045] Since the reduction in buckling strength of the container according to the present invention is suppressed, the value of the ratio of volume to mass (volume / mass) can be kept high. Thereby, it is possible to prevent the amount of polyester used from becoming excessive, reduce the amount of polyester to be discarded, improve the reduction of the environmental load, and improve 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.

[0046] Since the container according to the present invention has a suppressed reduction in buckling strength, the thickness of the container can be reduced. As a result, it is possible to prevent an excessive amount of polyester from being used, reduce the amount of polyester to be discarded, improve environmental load reduction, and also improve the blow moldability of the container. The thickness of the cross-section in 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. Note that the thickness means the location where the cross-sectional thickness is the thinnest.

[0047] The container according to the present invention may have a single-layer structure or a multi-layer structure of two or more layers. Further, when the container has a multi-layer structure, each layer may have the same composition or different compositions.

[0048] In one embodiment, the container may be provided with a vapor deposition film on its surface. Thereby, the gas barrier property of the container can be improved.

[0049] Examples of the vapor deposition film include a vapor deposition film composed of a metal such as aluminum, and inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, an organosilicon compound such as hexamethyldisiloxane, and a hard carbon film such as a DLC (Diamond Like Carbon) film. Note that the hard carbon film made of a DLC film is also called an i-carbon film or a hydrogenated amorphous carbon film (a-C:H), and is an amorphous carbon film mainly composed of SP 3 bonding.

[0050] Further, the thickness of the vapor deposition film is not particularly limited, and can be, for example, 1 nm or more and 150 nm or less.

[0051] The vapor deposition film can be formed using a conventionally known method, for example, physical vapor deposition methods such as vacuum vapor deposition method, sputtering method, and ion plating method (Physical Vapor Deposition method, PVD method), and chemical vapor deposition methods such as plasma chemical vapor deposition method, thermal chemical vapor deposition method, and photo chemical vapor deposition method (Chemical Vapor Deposition method, CVD method), etc. In addition, the thickness of the vapor deposition layer can be measured, for example, at the body portion of the container, and means the location where the thickness is the thinnest.

[0052] [Method for manufacturing a container] The container according to the present invention can be manufactured by blow molding a preform described later. The blow molding can be performed by a conventionally known method.

[0053] [Preform] In this specification, a preform is a preform before blow molding a container. The preform according to the present invention is used for manufacturing the container of the present 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 lower than the intrinsic viscosities of the recycled polyester and the virgin polyester. By configuring the preform in such a manner, the container according to the present invention can be manufactured. In addition, the polyester contained in the preform according to the present invention can be the same as that of the container according to the present invention.

[0054] Hereinafter, with reference to FIG. 2, an embodiment of the structure of the preform according to the present invention will be described.

[0055] Figure 2 is a schematic semi-cross-sectional view showing an embodiment of a preform according to the present invention. As shown in Figure 2, 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. Among 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. Further, 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.

[0056] 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 flange 35 provided below the screw portion 34 and corresponding to the flange 17 of the container 10, and a support ring 36 provided below the flange 35 and corresponding to the support ring 18 of the container 10. The shape of the mouth portion 31 may be a conventionally known shape.

[0057] The thickness of the cross-section of the preform according to the present invention is preferably 1.3 mm or more and 4.7 mm or less, and 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, a container according to the present invention can be manufactured. Note that the thickness of the cross-section of the preform can be measured, for example, at the body portion of the preform, and means the location where the thickness of the cross-section is the thinnest.

[0058] [Method for manufacturing a preform] The method for manufacturing a preform according to the present invention includes a step of dry-blending a crushed material (hereinafter also simply referred to as "crushed material") obtained by crushing waste in the manufacturing process of a container containing polyester as a main component, recycled polyester, and virgin polyester to obtain a mixture, a step of melting the mixture to obtain a melt, and a step of injection-molding the melt. The shape of the crushed material is not particularly limited, and examples thereof include spherical, polyhedral, needle-like, and columnar shapes. In the method for manufacturing a preform according to the present invention, recycled polyester and virgin polyester that are the same as those of the container according to the present invention can be used.

[0059] In the method for manufacturing a preform according to the present invention, the pulverized material, recycled polyester, and virgin polyester are pre-dry blended before being melted. By adopting such a process, a container in which the pulverized material, recycled polyester, and virgin polyester are uniformly dispersed can be manufactured.

[0060] In the method for manufacturing a preform according to the present invention, the mixing ratio of virgin polyester with respect to recycled polyester and the pulverized material is preferably 0.11 or more and 2.33 or less, more preferably 0.5 or more and 1.5 or less.

[0061] In the method for manufacturing a preform according to the present invention, the mixing ratio of the pulverized material with respect to 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, and still more preferably 0.05 or more and 0.08 or less.

[0062] In one embodiment, the forms of the recycled polyester and virgin polyester may be pellets or flakes. When the form of the recycled polyester is pellets, the pellets may be formed by melting flakes of the recycled polyester. In another embodiment, the form of the recycled polyester may be flakes and the form of the virgin polyester may be pellets.

[0063] In the method for manufacturing a preform according to the present invention, the melting of the mixture can be carried out by a conventionally known method, but the melting temperature is preferably 285°C or more and 300°C or less. By setting the melting temperature within this range, the pulverized material and recycled polyester can be melted, and discoloration of the container to yellow can be suppressed. The melting temperature is more preferably 285°C or more and 295°C or less. In addition, in this specification, the "melting temperature" refers to the temperature of the melted polyester.

[0064] In the method for producing a preform according to the present invention, the step of injection-molding the melt can be carried out by a conventionally known method.

Examples

[0065] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0066] [Example 1] Flaky recycled polyester, pelletized virgin polyester (manufactured by Shin-Kong Synthetic Fibers Co., Ltd., 5015W), and a pulverized product of pre-consumer polyester were prepared. First, the flaky polyester was melted to obtain pelletized recycled polyester. 45 parts by mass of the recycled polyester pellets, 50 parts by mass of the virgin polyester pellets, and 5 parts by mass of the pulverized product of 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. 2. The thickness of the body portion of the preform was 3.5 mm, and the basis weight was 21 g.

[0067] Next, the above preform was heated to 110°C, and biaxial stretch blow molding was performed in a blow molding mold to produce a container having an internal volume of 500 mL shown in FIG. 1. The thickness of the cross-section in the body portion of the container was 0.32 mm. In the polyester constituting the container, the volume / mass was 23.8.

[0068] [Example 2] A preform was produced in the same manner as in Example 1, except that 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 product of pre-consumer polyester were dry-blended to obtain a mixture.

[0069] Next, in the same manner as in Example 1, a container was produced from the above preform.

[0070] [Example 3] A preform was produced in the same manner as in Example 1, except that 45 parts by mass of the flakes of the recycled polyester, 50 parts by mass of the pellets of the virgin polyester, and 5 parts by mass of the pulverized product of the pre-consumer polyester were dry blended to obtain a mixture.

[0071] Next, in the same manner as in Example 1, a container was produced from the above preform.

[0072] [Example 4] A preform was produced in the same manner as in Example 1, except that 65 parts by mass of the flakes of the post-consumer recycled polyester, 30 parts by mass of the pellets of the virgin polyester, and 5 parts by mass of the pulverized product of the pre-consumer polyester were dry blended to obtain a mixture.

[0073] Next, in the same manner as in Example 1, a container was produced from the above preform.

[0074] [Comparative Example 1] A preform was produced in the same manner as in Example 1, except that only the pellets of the recycled polyester were used and the melting temperature was set at 305°C.

[0075] Next, in the same manner as in Example 1, a container was produced from the above preform.

[0076] [Comparative Example 2] A preform was produced in the same manner as in Example 1, except that only the pellets of the virgin polyester were used and the melting temperature was set at 305°C.

[0077] Next, in the same manner as in Example 1, a container was produced from the above preform.

[0078] [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 at 305°C.

[0079] Subsequently, a container was produced from the above preform in the same manner as in Example 1.

[0080] [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 at 305°C.

[0081] Subsequently, a container was produced from the above preform in the same manner as in Example 1.

[0082] [[Content of virgin polyester]] The content of the virgin polyester in the containers produced in the above Examples and Comparative Examples is shown in Table 1.

[0083] [[Measurement of buckling strength]] For the containers produced in the above Examples and Comparative Examples, after each was filled with 500 ml of the content liquid (water) and sealed with a cap, a buckling strength test was conducted in the upright state of each container. For the measurement of the buckling strength, a top load tester (buckling test apparatus) EH-1000 manufactured by Ebic Co., Ltd. was used. A load was applied from above the mouth portion at a constant speed, and the maximum load at which a so-called yielding state occurred was taken as the buckling strength. The measurement results are shown in Table 1.

[0084] [[Measurement of color]] A sample obtained by finely cutting only the mouth portion of the polyester containers produced in the above Examples and Comparative Examples was pre-cooled for 10 minutes under liquid nitrogen using a freezer mill (model 6870 Freezer / Mill manufactured by SPEX), and then freeze-ground for 10 minutes under liquid nitrogen to obtain a powder. Subsequently, using this powder, with a spectrophotometer (CMS-35SP manufactured by Murakami Color Technology Research Institute Co., Ltd.), in reflected light, L* a * b * The L value in the color system * , a * value, and b * value were measured. The measurement conditions were SCE (specular component excluded), 10° field of view, and D65 light source. The measurement was performed in accordance with JIS Z8722:2009. The measurement results are shown in Table 1.

[0085]

Table 1

[0086] The containers of Examples 1 to 4 are excellent in CO2 emission reduction compared to the container of Comparative Example 2 that uses only virgin polyester. The containers of Examples 1 to 4 have suppressed reduction in buckling strength compared to the container of Comparative Example 1 that uses only recycled polyester. The containers of Examples 1 and 3 have a small b value representing yellow, and thus yellowing is suppressed, compared to the container of Comparative Example 3 that uses only recycled polyester and virgin polyester. Also, the containers of Examples 2 and 4 have a small b value representing yellow, and thus yellowing is suppressed, compared to the container of Comparative Example 4 that uses only recycled polyester and virgin polyester. * value, and thus yellowing is suppressed. Also, the containers of Examples 2 and 4 have a small b value representing yellow, and thus yellowing is suppressed, compared to the container of Comparative Example 4 that uses only recycled polyester and virgin polyester. * value, and thus yellowing is suppressed.

Explanation of Reference Signs

[0087] 10: Container 11: Mouth part 12: Neck part 13: Shoulder part 14: Body part 15: Bottom part 16: Thread part 17: Cap 18: Support ring 19: Depression part 20: Grounding part 21: Panel part 30: Preform 31: Mouth part 32: Body part 33: Bottom part 34: Thread part 35: Washer 36: Support ring

Claims

1. A container containing polyester as a main component, wherein 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 viscosities of the recycled polyester and the virgin polyester. A container.

2. The container according to claim 1, wherein the intrinsic viscosity of the polyester made from the waste is 0.650 dL / g or more and 0.780 dL / g or less.

3. The container according to claim 1 or 2, wherein the intrinsic viscosities of the recycled polyester and the virgin polyester are 0.750 dL / g or more and 0.870 dL / g or less.

4. 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 polyester made from the waste is 0.11 or more and 2.33 or less.

5. The container according to any one of claims 1 to 4, wherein the ratio of the mass of the polyester made from the waste to the total mass of the recycled polyester and the virgin polyester is 0.001 or more and 0.111 or less.

6. The container according to any one of claims 1 to 5, wherein the ratio of volume to mass is 5 mL / g or more and 50 mL / g or less.

7. Comprising a mouth part, a neck part, a shoulder part, a body part, and a bottom part, The container according to any one of claims 1 to 6, wherein the thickness of the cross-section in the body part is 0.05 mm or more and 0.54 mm or less.

8. A preform for manufacturing the container according to any one of claims 1 to 7.

9. A method for manufacturing the preform according to claim 8, comprising: A step of dry-blending a pulverized product obtained by pulverizing waste in the container manufacturing process containing polyester as a main component, recycled polyester, and virgin polyester to obtain a mixture; A step of melting the mixture to obtain a melt; A step of injection-molding the melt; A method for manufacturing a preform.

10. The method for manufacturing a preform according to claim 9, wherein the forms of the recycled polyester and the virgin polyester are pellets.

11. The method for manufacturing a preform according to claim 10, wherein the pellets of the recycled polyester are formed by melting flakes of recycled polyester.

12. The manufacturing method of the preform according to claim 9, wherein the form of the recycled polyester is flakes and the form of the virgin polyester is pellets.

13. The manufacturing method of the preform according to any one of claims 9 to 12, wherein the temperature of the melting is 285°C or higher and 300°C or lower.

14. A method for manufacturing a container according to any one of claims 1 to 7, The method for manufacturing a container includes 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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