Polyester containers and polyester preforms

Abstract

To provide a polyester container having high environmental load reduction properties.SOLUTION: A polyester container is composed of polyester. In a differential molecular weight distribution obtained by measuring the polyester container by a gel permeation chromatograph, when each peak is subjected to waveform separation, the proportion of a peak area of a component having a peak top present in a range of 2500 or more and 6400 or less in molecular weight, is 6.00×10-4 or less relative to a total component peak area.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polyester container and a polyester preform used in the production of the polyester container. [Background technology]

[0002] Polyesters such as polyethylene terephthalate are widely used in the manufacture of containers for filling beverages and the like because they have excellent mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency, and are inexpensive. In recent years, there has been a demand for polyester containers, which have a high environmental impact. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention has been made in view of the above, and an object of the present invention is to provide a polyester container that has a high environmental load reduction property. Another object of the present invention is to provide a polyester preform for use in producing the polyester container. [Means for solving the problem]

[0004] The present invention provides a polyester container made of polyester, In the differential molecular weight distribution obtained by measuring polyester containers using gel permeation chromatography, when each peak was subjected to waveform separation, the ratio of the peak area of ​​components whose peak tops are in the range of molecular weights from 2500 to 6400 to the peak area of ​​all components was 6.00 x 10 -4 The following is a polyester container.

[0005] In one embodiment, the polyester container has a first layer and a second layer that form an inner layer, the first layer being made of virgin polyester and the second layer being made of recycled polyester.

[0006] In one embodiment, the polyester container further comprises a third layer constituting the outer layer, the third layer being made of virgin polyester.

[0007] In one embodiment, the polyester container has a mouth, a neck, a shoulder, a body, and a bottom, and the first layer is disposed in the content filling area.

[0008] In one embodiment, the polyester container has a mouth, a neck, a shoulder, a body, and a bottom, and the first layer extends from the top of the mouth to the bottom.

[0009] In one embodiment, the polyester is polyethylene terephthalate or modified polyethylene terephthalate.

[0010] In one embodiment, the cross-sectional thickness of the polyester container is 0.05 mm or more and 0.54 mm or less.

[0011] The present invention provides a polyester preform for producing the polyester container, The polyester preform is made of polyester, In the differential molecular weight distribution obtained by measuring polyester preform by gel permeation chromatography, when each peak was subjected to waveform separation, the ratio of the peak area of ​​components whose peak tops are in the range of molecular weights from 2500 to 6400 to the peak area of ​​all components was 6.00 x 10 -4 Below is a polyester preform. [Effects of the Invention]

[0012] According to the present invention, a polyester container having a high reduction in environmental impact can be provided. It is also possible to provide a polyester preform for use in producing the polyester container. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic half-sectional view showing one embodiment of a polyester container of the present invention. [Figure 2] 1 is a schematic half-sectional view showing one embodiment of a polyester container of the present invention. [Figure 3] 1 is a schematic half-sectional view showing one embodiment of a polyester container of the present invention. [Figure 4] 1 is a schematic half-sectional view showing one embodiment of a polyester container of the present invention. [Figure 5] 1 is a schematic half-sectional view showing one embodiment of a polyester container of the present invention. [Figure 6] 1 is a schematic half-sectional view showing one embodiment of a polyester container of the present invention. [Figure 7] 1 is a schematic half-sectional view showing one embodiment of a polyester preform of the present invention. [Figure 8] 1 is a schematic half-sectional view showing one embodiment of a polyester preform of the present invention. [Figure 9] 1 is a schematic half-sectional view showing one embodiment of a polyester preform of the present invention. [Figure 10] 1 is a schematic half-sectional view showing one embodiment of a polyester preform of the present invention. [Figure 11] 1 is a schematic half-sectional view showing one embodiment of a polyester preform of the present invention. [Figure 12] 1 is a schematic half-sectional view showing one embodiment of a polyester preform of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Polyester container> The polyester container of the present invention is made of polyester. In the present invention, "polyester" means a copolymer of a dicarboxylic acid compound and a diol compound. Examples of dicarboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethylmalonic acid, adamantanedicarboxylic 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-sodiumsulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid, 9,9'-bis(4-carboxyphenyl)fluorene acid, and ester derivatives thereof. Examples of diol compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, cyclohexanediethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanedimethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindimethanol, decalindiethanol, 5-methyl-1,3-propanediol ... -methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxycyclohexylpropane), 2,2-bis(4-(2-hydroxyethoxy)cyclohexyl)propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamantanediol, paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, and pentaerythritol. The polyester is preferably polyethylene terephthalate, which is a copolymer of terephthalic acid and ethylene glycol, or modified polyethylene terephthalate in which a copolymerization monomer is added to the polyethylene terephthalate.

[0015] As long as the characteristics of the present invention are not impaired, the polyester of the polyester container may contain monomers other than dicarboxylic acid compounds and diol compounds, but the content thereof is preferably 10 mol % or less, more preferably 5 mol % or less, and even more preferably 3 mol % or less, of the total constituent units.

[0016] In the polyester container of the present invention, when each peak is subjected to waveform separation in the differential molecular weight distribution measured by gel permeation chromatography, the ratio of the peak area of ​​components having peak tops in the molecular weight range of 2500 to 6400 to the peak area of ​​all components is 6.00 × 10 -4 The present invention is characterized by the following: As will be described later, polyester containers can be produced by first injection-molding polyester to prepare a polyester preform, and then blow-molding this. If a polyester container contains a certain amount or more of oligomers whose peak tops are in the molecular weight range of 2500 to 6400, it becomes difficult to maintain constant molding conditions in the injection molding of the polyester and the blow molding of the polyester preform, ultimately resulting in a decrease in the yield of the polyester container. The polyester container of the present invention is produced by measuring the polyester container by gel permeation chromatography, and when each peak is subjected to waveform separation, the ratio of the peak area of ​​components whose peak tops are in the molecular weight range of 2500 to 6400 is 6.00 × 10 to the peak area of ​​all components. -4 By setting the following conditions, it becomes possible to maintain constant molding conditions and improve the yield of polyester containers. As a result, resource conservation is achieved by reducing waste products, and the amount of energy consumed in the production of polyester containers is reduced, resulting in polyester containers with a high environmental load reduction. In the polyester container of the present invention, the preferred peak area ratio is 5.50×10 -4 or less, more preferably 5.00 x 10 -4 The following is the result.

[0017] The differential molecular weight distribution of the polyester container can be measured by a known method using gel permeation chromatography (GPC). In the present invention, in the differential molecular weight distribution obtained under the following conditions, each peak is subjected to waveform separation to determine the proportion of the peak area of ​​components whose peak tops are in the molecular weight range of 2500 to 6400. First, approximately 10 mg of a sample is dissolved in a mixed solvent of chloroform and 1,1,1,3,3,3,3-hexafluoro-2-propanol (HFIP), and this is further diluted with chloroform to make a 0.1% by mass solution. Then, this is filtered and measured using GPC under the following conditions. Mobile phase: Chloroform Flow rate 1.0mL / min Injection volume 2.5μL Column temperature: 40°C Detector UV-visible detector Detection 254nm Molecular weight standard: Monodisperse polystyrene The equipment used was a 515 HPLC pump, 717plus automatic injection device, and 2487 UV-visible detector manufactured by Nihon Waters Co., Ltd., and a 2x PLgel 5μ MIXED-D 7.5×300mm column manufactured by Agilent Technologies, Inc. In the obtained differential molecular weight distribution, each peak is subjected to waveform separation, and the proportion of the peak area of ​​components whose peak tops are within the molecular weight range of 2500 to 6400 is determined. The waveform separation of each peak is performed by fitting with a Wesslau log-normal distribution function. Igor (WaveMetrics) can be used as the waveform separation software.

[0018] In one embodiment, the polyester of the polyester container includes recycled polyester, which can further improve the environmental load reduction of the polyester container. "Recycled polyester" refers to chemically recycled polyester or mechanically recycled polyester. Chemically recycled polyester refers to polyester obtained by breaking down polyester containers to the monomer level and then repolymerizing them. Mechanically recycled polyester refers to polyester obtained by sorting, crushing, and washing polyester containers to remove contaminants and foreign matter, obtaining flakes, and then treating the flakes for a certain period of time under high temperature and reduced pressure to remove contaminants from within the resin.

[0019] In one embodiment, the polyester of the polyester container includes virgin polyester. In the present invention, "virgin polyester" refers to polyester that has not been subjected to the above-mentioned recycling process, i.e., unused polyester. In addition to storing beverages, polyester containers are also used to store non-food items (e.g., pesticides and machine oil). When polyester containers used to store such non-food items are recycled, if contaminants are not sufficiently removed by washing, there is a risk that contaminants will leach into the contents in the polyester container made from recycled polyester. Therefore, by using polyester that contains virgin recycled polyester, the hygiene of the polyester container can be improved. The polyester of the polyester container may contain recycled polyester and virgin polyester.

[0020] When the polyester container of the present invention contains recycled polyester, the content of recycled polyester is preferably 30 parts by mass or more and 95 parts by mass or less, more preferably 50 parts by mass or more and 80 parts by mass or less, and even more preferably 60 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the total amount of resin material contained in the polyester container. By setting the content of recycled polyester to 30 parts by mass or more per 100 parts by mass of the total amount of resin materials contained in the polyester container, the environmental load of the polyester container can be further reduced. By setting the content of recycled polyester to 95 parts by mass or less per 100 parts by mass of the total amount of resin materials contained in the polyester container, the hygienic properties of the polyester container can be further improved. Furthermore, when the polyester container has a second layer as described below, it is possible to prevent the recycled polyester from being exposed to the first or third layer during the production of a polyester preform.

[0021] As long as the characteristics of the present invention are not impaired, the polyester may be one polymerized using a polymerization catalyst, such as a manganese catalyst, a titanium catalyst, an aluminum catalyst, a lithium catalyst, a germanium catalyst, or an antimony catalyst. When the polyester container of the present invention is filled with heated contents or when the polyester container is heated after being filled with contents, it is preferable to use a catalyst other than an antimony catalyst for polymerization, which can prevent antimony from leaching into the contents.

[0022] Examples of the manganese catalyst include fatty acid manganese salts such as manganese acetate, manganese carbonate, manganese chloride, manganese acetylacetonate salts, and manganese hydroxide. Examples of titanium catalysts include titanium alkoxides such as tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, and tetrabenzyl titanate; titanium oxides obtained by hydrolysis of titanium alkoxides; titanium acetate, titanium oxalate, potassium titanium oxalate, sodium titanium oxalate, potassium titanate, sodium titanate, titanate-aluminum hydroxide mixtures, titanium chloride, titanium chloride-aluminum chloride mixtures, titanium bromide, titanium fluoride, potassium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, ammonium hexafluorotitanate, and titanium acetylacetonate. Examples of aluminum catalysts include aluminum trisacetylacetate, aluminum monoacetylacetonate bis(ethylacetoacetate), and ethylacetoacetate aluminum diisopropylate. Examples of the lithium catalyst include ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, and phenyllithium. Examples of germanium catalysts include germanium dioxide, germanium tetroxide, germanium tetramethoxide, germanium tetraethoxide, germanium tetrapropoxide, germanium tetrabutoxide, germanium tetrapentoxide, and germanium tetrahexoxide. Examples of antimony catalysts include antimony trioxide, antimony pentoxide, antimony acetate, triphenylantimony, and antimony glycol.

[0023] The polyester container may contain additives, as long as they do not impair the properties of the present invention. Examples of such additives include oxygen absorbers, gas barrier resins (polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6)), plasticizers, ultraviolet stabilizers, antioxidants, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and colorants.

[0024] The polyester container of the present invention may have a vapor-deposited film over the entire inner surface of the container, thereby improving the gas barrier properties of the polyester container.

[0025] Examples of the vapor-deposited film include vapor-deposited films composed of 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, organic silicon compounds such as hexamethyldisiloxane, and hard carbon films such as DLC (Diamond Like Carbon) films. The hard carbon film made of DLC is also called i-carbon film or hydrogenated amorphous carbon film (aC:H), and is a hard carbon film. 3 It is an amorphous carbon film that is mainly composed of bonds.

[0026] The thickness of the vapor-deposited film is not particularly limited, and can be, for example, 1 nm or more and 150 nm or less.

[0027] The vapor deposition film can be formed by a conventionally known method, for example, physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0028] Fig. 1 is a schematic half-sectional view showing one embodiment of a polyester container 10 of the present invention. In one embodiment, the polyester 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. 1.

[0029] In one embodiment, the mouth portion 11 includes a threaded portion 16 onto which a cap is screwed, a cap 17 below the threaded portion 16, and a support ring 18 below the cap 17, as shown in FIG.

[0030] 1, the neck portion 12 is located between the support ring 18 and the shoulder portion 13 and has a generally cylindrical shape with a generally uniform diameter. The shoulder portion 13 also has a cylindrical shape with a diameter that gradually increases from the neck portion 12 side toward the body portion 14 side.

[0031] In one embodiment, as shown in Fig. 1, body 14 is located between shoulder 13 and bottom 15. Also, as shown in Fig. 1, body 14 includes panel 21. This configuration makes it possible to prevent deformation of the container due to changes in internal pressure when filling a polyester container with heated contents or when the polyester container is heated after being filled with contents.

[0032] 1, bottom 15 has a centrally located recessed portion 19 and a ground contact portion 20 provided around recessed portion 19, and is connected to body 14 at ground contact portion 20. This configuration makes it possible to prevent deformation of the container due to increases or decreases in internal pressure when heated contents are filled into the polyester container or when the polyester is heated after being filled with the contents. In one embodiment, the "bottom" refers to the inner part from the part that touches the ground when the polyester container is placed upright.

[0033] The polyester container of the present invention may be constructed of a single layer, two or more layers, or a combination of a single layer and a multilayer. An example of an embodiment in which the polyester container of the present invention has a multilayer structure will be described below with reference to FIGS.

[0034] In one embodiment, the polyester container 10 of the present invention has a first layer 22 and a second layer 23, as shown in FIGS. 2 and 3, with the first layer 22 constituting the inner layer.

[0035] In one embodiment, the polyester container 10 of the present invention has a first layer 22, a second layer 23, and a third layer 24, as shown in circle A in Figures 4 to 6, with the first layer 22 constituting the inner layer and the third layer 24 constituting the outer layer. The second layer 23 may be provided, for example, from the upper end of the mouth portion 11 to the bottom portion 15 (see FIGS. 4 and 5). The second layer 23 may also be provided in a portion of the polyester container, for example, from the lower end of the mouth 11 to the bottom 15 (see FIG. 6). When the first layer 22 and the third layer 24 are made of the same material, as shown in FIG. 6, these layers form a single layer in the area where the second layer 23 is not provided.

[0036] Details of the mouth portion 11, neck portion 12, shoulder portion 13, body portion 14, bottom portion 15, screw portion 16, cap 17, support ring 18, recessed portion 19, ground contact portion 20, and panel portion 21 have been described above, so they will not be described here.

[0037] The polyester 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 making the volume / weight of the polyester container 5 mL / g or more, the blow moldability of the polyester container can be improved, and excessive polyester usage can be prevented, thereby reducing the amount of polyester discarded and further reducing the environmental impact. Furthermore, by setting the volume / weight of the polyester container to 50 mL / g or less, the strength of the polyester container can be improved.

[0038] The cross-sectional thickness of the polyester container of the present invention is preferably 0.05 mm or more and 0.54 mm or less, and more preferably 0.1 mm or more and 0.5 mm or less. By making the cross-sectional thickness 0.05 mm or more, the strength of the polyester container can be further improved. Furthermore, by setting the cross-sectional thickness to 0.54 mm or less, the blow moldability of the polyester container can be improved, and the amount of polyester used can be prevented from becoming excessive, thereby reducing the environmental impact. The cross-sectional thickness of the polyester container means, for example, the portion of the body of the polyester container where the cross-sectional thickness is the thinnest.

[0039] (1st layer) In one embodiment, the first layer of the polyester container of the present invention is made of the above-mentioned virgin polyester, which prevents the recycled polyester from coming into contact with the contents even when the polyester container is made of recycled polyester, thereby improving the hygiene of the polyester container.

[0040] As long as the characteristics of the present invention are not impaired, the virgin polyester constituting the first layer may be one polymerized using the above-mentioned polymerization catalyst. When the polyester container of the present invention is filled with heated contents or heated after being filled with contents, it is preferable that the virgin polyester of the first layer is polymerized using a catalyst other than an antimony catalyst, which can prevent antimony from leaching into the contents.

[0041] The first layer may contain additives, as long as they do not impair the properties of the present invention. Examples of such additives include oxygen absorbers, gas barrier resins (polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6)), plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and color pigments.

[0042] In one embodiment, the first layer of the polyester container is provided in a content filling area. In the present invention, the "content filling area" refers to the area where the content comes into contact with the polyester container when the polyester container is filled with the content and placed upright. In one embodiment, the first layer is provided from a position 5 to 70 mm below the upper end of the mouth to the bottom 15. Preferably, the first layer is provided from a position 5 to 15 mm below the upper end of the mouth to the bottom 15. By providing the first layer from a position 5 to 70 mm below the top end of the mouth portion to the bottom, the first layer can cover the content filling area, and even if recycled polyester is used in the polyester container, the recycled polyester can be prevented from coming into contact with the contents, further improving the hygiene of the polyester container. Furthermore, by providing the first layer from a position 5 to 70 mm below the top end of the mouth portion to the bottom, it is possible to effectively prevent the mouth portion from cracking during capping by an automatic machine.

[0043] In one embodiment, the first layer of the polyester container extends from a position 70 mm below the top of the mouth to the bottom. The first layer is preferably provided from 15 mm below the top edge of the mouth to the bottom, thereby covering the content filling area and preventing the recycled polyester from coming into contact with the content, even when recycled polyester is used in the polyester container, thereby further improving the hygiene of the polyester container. Furthermore, in the polyester container of the present invention, it is more preferable that the first layer is provided from the top end of the mouth to the bottom, which further reduces contact of the recycled polyester with the contents even when the container is stored on its side in a vending machine or the like and heated, thereby further improving the hygiene of the polyester container.

[0044] The thickness of the first layer in the polyester container is preferably 0.01 mm or more and 0.33 mm or less, more preferably 0.025 mm or more and 0.3 mm or less, and even more preferably 0.025 mm or more and 0.1 mm or less. By making the thickness of the first layer 0.01 mm or more, even when recycled polyester is used in a polyester container, the recycled polyester can be effectively prevented from coming into contact with the contents. Furthermore, by setting the thickness of the first layer to 0.33 mm or less, the proportion of the second layer in the polyester container can be increased, and the environmental load reduction of the polyester container can be further improved. The thickness of the first layer means, for example, the portion of the body of the polyester container where the thickness of the first layer is the thinnest.

[0045] (2nd layer) In one embodiment, the second layer of the polyester container of the present invention is made of the recycled polyester, which can further reduce the environmental impact of the polyester container.

[0046] The recycled polyester constituting the second layer may be one polymerized using the above-mentioned polymerization catalyst, provided that the characteristics of the present invention are not impaired.

[0047] The second layer may contain additives, as long as they do not impair the properties of the present invention. Examples of such additives include oxygen absorbers, gas barrier resins (polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6)), plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and color pigments.

[0048] The thickness of the second layer in the polyester container is preferably 0.04 mm or more and 0.49 mm or less, more preferably 0.1 mm or more and 0.4 mm or less, and even more preferably 0.1 mm or more and 0.22 mm or less. By making the thickness of the second layer 0.04 mm or more, the environmental load of the polyester container can be further reduced. Furthermore, by setting the thickness of the second layer to 0.49 mm or less, it is possible to prevent the recycled polyester from being exposed to the contents side during the production of the polyester preform. The thickness of the second layer means, for example, the portion of the body of the polyester container where the thickness of the second layer is the thinnest.

[0049] (3rd layer) In one embodiment, the third layer of the polyester container of the present invention is made of the above-mentioned virgin polyester, which can improve the heat resistance and strength of the polyester container.

[0050] The virgin polyester constituting the third layer may be polymerized using the above-mentioned polymerization catalyst, provided that the properties of the present invention are not impaired. The third layer may also be made of the same material as the first layer.

[0051] The third layer may contain additives, as long as they do not impair the properties of the present invention. Examples of such additives include oxygen absorbers, gas barrier resins (polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6)), plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and color pigments.

[0052] The thickness of the third layer in the polyester container is preferably 0.01 mm or more and 0.1 mm or less, and more preferably 0.025 mm or more and 0.05 mm or less. By making the thickness of the third layer 0.01 mm or more, the heat resistance and strength of the polyester container can be further improved. Furthermore, by setting the thickness of the third layer to 0.1 mm or less, the proportion of the second layer in the polyester container can be increased, and the environmental load reduction of the polyester container can be further improved. The thickness of the third layer means, for example, the portion of the body of the polyester container where the thickness of the third layer is the thinnest.

[0053] <Polyester preform> The polyester preform of the present invention is used for producing polyester containers. The polyester preform of the present invention is made of polyester.

[0054] In the polyester preform of the present invention, when each peak is subjected to waveform separation in the differential molecular weight distribution measured by gel permeation chromatography, the ratio of the peak area of ​​components having peak tops in the molecular weight range of 2500 to 6400 to the peak area of ​​all components is 6.00 × 10 -4 The polyester preform of the present invention is characterized in that the ratio of the peak area is 5.50×10 or less. This allows the polyester container as described above to be obtained. -4 or less, more preferably 5.00 x 10 -4 The following is the result. In the polyester preform, the peak area ratio can be obtained by the same method as in the polyester container.

[0055] As for other elements, the polyester constituting the polyester preform may be the same as the polyester for the polyester container described above.

[0056] The polyester preform may contain additives, as long as they do not impair the properties of the present invention. Examples of such additives include oxygen absorbers, gas barrier resins (polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6)), plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and color pigments.

[0057] 7 is a schematic half-sectional view showing one embodiment of the polyester preform of the present invention. In one embodiment, the polyester preform 30 of the present invention includes a mouth portion 31, a body portion 32, and a bottom portion 33, as shown in FIG. 7, the mouth 31 corresponds to the mouth 11 of the polyester container 10 described above and has substantially the same shape as the mouth 11. In one embodiment, the body 32 corresponds to the neck 12, shoulder 13, and body 14 of the polyester container 10 described above and has a substantially cylindrical shape. In one embodiment, the bottom 33 corresponds to the bottom 15 of the polyester container 10 described above and has a substantially hemispherical shape. In one embodiment, the mouth portion 31 includes a threaded portion 34 onto which the cap is screwed, a cap 35 below the threaded portion 34, and a support ring 36 below the cap 35, as shown in FIG.

[0058] The polyester preform of the present invention may be constructed of a single layer, or two or more layers, or may be constructed of a combination of a single layer and a multilayer. An example of an embodiment in which the polyester preform of the present invention has a multilayer structure will be described with reference to FIGS.

[0059] In one embodiment, as shown in FIGS. 8 and 9, the polyester preform 30 of the present invention has a first layer 37 and a second layer 38, with the first layer 37 constituting the inner layer.

[0060] In one embodiment, as shown in Figures 10 to 12, the polyester preform 30 of the present invention has a first layer 37, a second layer 38, and a third layer 39, with the first layer 37 constituting the inner layer and the third layer 39 constituting the outer layer. The second layer 38 may be provided, for example, from the lower end of the bottom portion 33 to the upper end of the mouth portion 31 (see FIGS. 10 and 11). The second layer 38 may also be provided on a part of the polyester preform, for example, from the lower end of the bottom portion 33 to the lower end of the mouth portion 31 (see FIG. 12). When the first layer 37 and the third layer 39 are made of the same material, as shown in FIG. 12, these layers become a single layer in the area where the second layer 38 is not provided.

[0061] The details of the mouth portion 31, the body portion 32, the bottom portion 33, the threaded portion 34, the cap 35, and the support ring 36 have been described above, and therefore will not be described here.

[0062] The cross-sectional thickness of the polyester preform of 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 cross-sectional thickness within the above range, the polyester container described above can be obtained. The cross-sectional thickness of the polyester preform means, for example, the portion of the body of the polyester preform where the cross-sectional thickness is the thinnest.

[0063] (1st layer) In one embodiment, as shown in Figures 8 and 10, when the distance from the lower end of the bottom 33 to the upper end of the mouth 31 is L, the polyester preform 30 has the first layer 37 provided in a range of 0.4L to 0.97L from the lower end. Since the first layer 37 is provided within a range of 0.4 L or more from the lower end of the bottom 33, when the polyester preform is blow molded into a polyester container, the first layer can cover the content filling area, and even when recycled polyester is used, the recycled polyester can be prevented from coming into contact with the contents, further improving the hygiene of the polyester container. Furthermore, since the first layer 37 is provided within a range of 0.97 L or less from the lower end of the bottom 33, when the polyester preform is blow molded into a polyester container, cracks at the mouth can be effectively prevented when capping is performed using an automatic machine.

[0064] In one embodiment, the first layer may be provided from the lower end of the base to the upper end of the mouth, or from the lower end of the base to the lower end of the mouth.

[0065] The material constituting the first layer of the polyester preform may be the same as the material constituting the first layer of the polyester container.

[0066] The thickness of the first layer in the polyester preform is preferably 0.1 mm or more and 2.9 mm or less, and more preferably 0.2 mm or more and 2.0 mm or less. Furthermore, when the polyester preform has a third layer, the thickness of the first layer in the polyester preform is preferably 0.05 mm or more and 1.5 mm or less, and more preferably 0.1 mm or more and 1.0 mm or less. By setting the thickness of the first layer in the polyester preform within the above range, the polyester container as described above can be obtained. The thickness of the first layer in the polyester preform means, for example, the portion in the body of the polyester preform where the thickness of the first layer is the thinnest.

[0067] (2nd layer) The material constituting the second layer of the polyester preform may be the same as the material constituting the second layer of the polyester container.

[0068] The thickness of the second layer in the polyester preform is preferably 0.5 mm or more and 4.3 mm or less, and preferably 1.9 mm or more and 4.0 mm or less. Furthermore, when the polyester preform has a third layer, the thickness of the second layer in the polyester preform is preferably 0.4 mm or more and 3.7 mm or less, and preferably 1.6 mm or more and 3.4 mm or less. By setting the thickness of the second layer in the polyester preform within the above range, the polyester container as described above can be obtained. The thickness of the second layer in the polyester preform means, for example, the portion in the body of the polyester preform where the thickness of the second layer is the thinnest.

[0069] (3rd layer) The material constituting the third layer of the polyester preform may be the same as the material constituting the third layer of the polyester container.

[0070] The thickness of the third layer in the polyester preform is preferably 0.05 mm or more and 1.5 mm or less, and more preferably 0.1 mm or more and 1.0 mm or less. By setting the thickness of the third layer in the polyester preform within the above range, the polyester container as described above can be obtained. The thickness of the third layer in the polyester preform means, for example, the thickness of the third layer at the body of the polyester preform, at a location where the thickness is the thinnest.

[0071] <Manufacturing method of polyester containers> In one embodiment, the polyester container shown in FIG. 1 can be produced by injection molding the above-mentioned polyester to prepare a polyester preform, and then blow molding the polyester preform.

[0072] In one embodiment, the polyester container of the present invention can be manufactured by co-injection molding the materials constituting the first and second layers to produce a polyester preform, which is then blow-molded. The formation position of each layer can be adjusted by injection molding conditions such as the resin temperature.

[0073] The polyester container shown in FIG. 2 can also be produced by two-color molding or insert molding. Furthermore, the polyester container shown in FIG. 2 and the like can be produced by injection-molding virgin polyester into an inner mold to form a first layer, retracting the inner mold to form a gap between the inner mold and the first layer, and then injection-molding recycled polyester into this gap to form a second layer.

[0074] In one embodiment, the polyester container of the present invention can be manufactured by producing a preform by co-injection molding the materials constituting the first, second, and third layers described above, and then blow molding the preform. When the second layer is formed on a part of the preform, it is preferable to use the hot runner nozzle disclosed in Japanese Patent Application Laid-Open No. 2008-94454.

[0075] The polyester container shown in FIG. 4 can also be produced by three-color molding or insert molding. Furthermore, the polyester container shown in Figure 4, etc., can be produced by injection-molding virgin polyester into an inner mold to form a first layer, retracting the inner mold to leave a gap between the inner mold and the first layer, injection-molding recycled polyester into this gap to form a second layer, retracting the inner mold to leave a gap between the inner mold and the first and second layers, and injection-molding virgin polyester into this gap to form a third layer. [Example]

[0076] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0077] <Gel permeation chromatography measurement conditions> Equipment: 515 HPLC pump, 717plus automatic injection device (manufactured by Nihon Waters Co., Ltd.) Column: 2x PLgel 5μ MIXED-D 7.5 x 300 mm (Agilent Technologies) Mobile phase: Chloroform Flow rate 1.0mL / min Injection volume 2.5μL Column temperature: 40°C Detector: UV-visible detector (Nihon Waters, 2487 UV-visible detector) Detection 254nm Molecular weight standard: Monodisperse polystyrene (Agilent Technologies, PS-1)

[0078] (Method for measuring molecular weight using gel permeation chromatography) The molecular weights of the polyester container and the polyester pellets were measured using gel permeation chromatography. To measure, a polyester container was first cut in the middle of its height to prepare a square sample approximately 1 cm on each side. Approximately half of this sample (approximately 10 mg) was weighed into a 30 mL vial, and a mixed solvent of chloroform and 1,1,1,3,3,3,3-hexafluoro-2-propanol (HFIP) was added. The solution was left overnight to dissolve the sample. This was further diluted with chloroform to obtain a 0.1% by mass solution. This solution was then filtered through a 0.45 μm hydrophilic PTFE membrane filter cartridge (Millex-LH, Merck Millipore), and the filtrate was measured. For polyester pellets, a single pellet was weighed, dissolved, diluted, and filtered in the same manner, and the filtrate was measured. The differential molecular weight distribution was obtained from the measurement results. In the obtained differential molecular weight distribution, the peaks were separated into seven components, and the proportion of the peak area of ​​components whose peak tops were within the molecular weight range of 2500 to 6400 was determined. The waveform separation was performed using Igor (WaveMetrics) as waveform separation software, by fitting with Wesslau's log-normal distribution function.

[0079] Example 1 The differential molecular weight distribution obtained by measuring the pellets using gel permeation chromatography was subjected to waveform separation into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weights from 2500 to 6400 to the peak area of ​​all components was 4.86 x 10 -4 We have prepared mechanically recycled polyester. This was injected into an injection molding machine to produce a polyester preform having a mouth, a body, and a bottom. The mouth of the polyester preform was equipped with a male thread, a turnip, and a support ring in that order from the top of the mouth. The cross-sectional thickness of the body of the polyester preform was 3.5 mm, and the weight per unit area was 22 g.

[0080] Next, the polyester preform was heated to 110°C and subjected to biaxial stretch blow molding in a blow molding die to obtain a polyester container with a capacity of 500 mL and the shape shown in Figure 2. The cross-sectional thickness of the body of the polyester container was 0.32 mm.

[0081] Next, the molecular weight of the polyester container was measured using gel permeation chromatography according to the method described above. In the differential molecular weight distribution obtained from the measurement results, the peaks were separated into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weight between 2500 and 6400 to the peak area of ​​all components was 6.41 x 10 -5 It was. In this example, the number of polyester containers that were defectively molded during production was 0 out of 100.

[0082] Example 2 The differential molecular weight distribution obtained by measuring the pellets using gel permeation chromatography was subjected to waveform separation into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weights from 2500 to 6400 to the peak area of ​​all components was 4.86 x 10 -4 The differential molecular weight distribution of the mechanically recycled polyester and pellets was measured by gel permeation chromatography. The peaks were separated into seven components, and the ratio of the peak area of ​​the components with peak tops in the molecular weight range of 2500 to 6400 was 8.23 ​​x 10 to the peak area of ​​all components. -3 We prepared polyester that has not been recycled. These were co-injected using an injection molding machine to create a multilayer (two-layer, two-type) preform shown in Figure 9, which has a first layer made of non-recycled polyester and a second layer made of mechanically recycled polyester. The amount of mechanically recycled polyester used was adjusted to 80 parts by mass per 100 parts by mass of the resin material constituting the multilayer preform. The cross-sectional thickness of the body of the multilayer preform was 3.5 mm, and the weight per unit area was 22 g.

[0083] The multilayer preform was then heated to 110°C and subjected to biaxial stretch blow molding in a blow molding die to obtain a multilayer container with a capacity of 500 mL and the shape shown in Figure 3. The cross-sectional thickness of the body of the polyester container was 0.32 mm.

[0084] Next, the molecular weight of the polyester container was measured in the same manner as in Example 1. In the differential molecular weight distribution obtained from the measurement results, the peaks were separated into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weight between 2500 and 6400 to the peak area of ​​all components was 1.40 x 10 -4 It was. In this example, the number of polyester containers that were defectively molded during production was 0 out of 100.

[0085] Example 3 The differential molecular weight distribution obtained by measuring the pellets using gel permeation chromatography was subjected to waveform separation into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weights from 2500 to 6400 to the peak area of ​​all components was 4.86 x 10 -4 The differential molecular weight distribution of the mechanically recycled polyester and pellets was measured by gel permeation chromatography. The peaks were separated into seven components, and the ratio of the peak area of ​​the components with peak tops in the molecular weight range of 2500 to 6400 was 8.23 ​​x 10 to the peak area of ​​all components. -3 We prepared polyester that has not been recycled. These were co-injected using an injection molding machine to create a multilayer (two-type, three-layer) preform shown in Figure 11, which had a first layer made of non-recycled polyester, a second layer made of mechanically recycled polyester, and a third layer made of non-recycled polyester. The amount of mechanically recycled polyester used was adjusted to 50 parts by mass per 100 parts by mass of the resin material constituting the multilayer preform. The cross-sectional thickness of the body of the multilayer preform was 3.5 mm, and the weight per unit area was 22 g.

[0086] The multilayer preform was then heated to 110°C and subjected to biaxial stretch blow molding in a blow molding die to obtain a multilayer container with a capacity of 500 mL and the shape shown in Figure 5. The cross-sectional thickness of the body of the polyester container was 0.32 mm.

[0087] Next, the molecular weight of the polyester container was measured in the same manner as in Example 1. In the differential molecular weight distribution obtained from the measurement results, the peaks were separated into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weight between 2500 and 6400 to the peak area of ​​all components was 3.36 x 10 -4 It was. In this example, the number of polyester containers that were defectively molded during production was 0 out of 100.

[0088] Comparative Example 1 The differential molecular weight distribution obtained by measuring the pellets using gel permeation chromatography was subjected to waveform separation into seven components. The ratio of the peak area of ​​components with peak tops in the molecular weight range of 2500 to 6400 to the peak area of ​​all components was 3.68 x 10 -3A polyester preform was produced in the same manner as in Example 1, except that a mechanically recycled polyester of 2500 or more and 6400 or less was used. The cross-sectional thickness of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g. Furthermore, a polyester container was produced in the same manner as in Example 1 using the polyester preform of this comparative example, and the molecular weight was measured. The cross-sectional thickness of the body of the polyester container was 0.32 mm. In the differential molecular weight distribution obtained from the measurement results, the peaks were waveform separated into seven components, and the ratio of the peak area of ​​the component having a peak top in the molecular weight range of 2500 to 6400 was 8.48 × 10 to the peak area of ​​all components. -4 It was. In this example, two out of 100 polyester containers were defectively molded during production.

[0089] Comparative Example 2 In the differential molecular weight distribution obtained by measuring the pellets by gel permeation chromatography, the peaks were separated into seven components. The ratio of the peak area of ​​the components whose peak tops are in the range of molecular weights from 2500 to 6400 was 8.23 ​​x 10 to the peak area of ​​all components. -3 A polyester preform was produced in the same manner as in Example 1, except that a non-recycled polyester of 2500 or more and 6400 or less was used. The cross-sectional thickness of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g. Furthermore, a polyester container was produced in the same manner as in Example 1 using the polyester preform of this comparative example, and the molecular weight was measured. The cross-sectional thickness of the body of the polyester container was 0.32 mm. In the differential molecular weight distribution obtained from the measurement results, the peaks were waveform separated into seven components, and the ratio of the peak area of ​​the component having a peak top in the molecular weight range of 2500 to 6400 was 5.58 × 10 to the peak area of ​​all components. -3 It was. In this example, two out of 100 polyester containers were defectively molded during production.

[0090] In the above examples and comparative examples, the ratio of the peak area of ​​components having peak tops in the molecular weight range of 2500 to 6400 to the peak area of ​​all components was 6.00 × 10 -4 It can be seen that the polyester containers shown below have improved yield and are polyester containers with a high reduction in environmental impact. [Explanation of symbols]

[0091] 10: Polyester container 11: Mouth 12: Neck 13:Shoulder 14: Torso 15: Bottom 16: Threaded part 17: Turnip 18: Support ring 19: Depression 20: Grounding part 21: Panel section 22: 1st layer 23:Second layer 24:Third layer 30: Polyester preform 31: Mouth 32: Torso 33: Bottom 34: Threaded part 35: Turnip 36: Support ring 37: 1st layer 38:Second layer 39:Third layer

Claims

1. A single-layer polyester container made of polyester, The polyester comprises mechanically recycled polyester, In a differential molecular weight distribution obtained by measuring the polyester by gel permeation chromatography, when each peak is subjected to waveform separation, the ratio of the peak area of ​​a component having a peak top within a molecular weight range of 2,500 or more and 6,400 or less to the peak area of ​​all components is 4.77×10 −4 or more and 4.95×10 −4 or less; In the differential molecular weight distribution obtained by measuring the polyester container by gel permeation chromatography, when each peak is subjected to waveform separation, the ratio of the peak area of ​​components having peak tops in the molecular weight range of 2500 to 6400 to the peak area of ​​all components is 6.29 × 10 -5 or more and 6.53 × 10 -5 or less.

2. 2. The polyester container according to claim 1, wherein the polyester is polyethylene terephthalate or modified polyethylene terephthalate.

3. 3. The polyester container according to claim 1, wherein the thickness of the cross section of the polyester container is 0.05 mm or more and 0.54 mm or less.

4. A polyester preform for producing the polyester container according to any one of claims 1 to 3, The polyester preform is made of polyester, The polyester comprises mechanically recycled polyester, In a differential molecular weight distribution obtained by measuring the polyester by gel permeation chromatography, when each peak is subjected to waveform separation, the ratio of the peak area of ​​a component having a peak top within a molecular weight range of 2,500 or more and 6,400 or less to the peak area of ​​all components is 4.77×10 −4 or more and 4.95×10 −4 or less; In a differential molecular weight distribution obtained by measuring the polyester preform by gel permeation chromatography, when each peak is subjected to waveform separation, the ratio of the peak area of ​​components having peak tops in a molecular weight range of 2,500 or more and 6,400 or less to the peak area of ​​all components is 6.29 × 10 -5 or more and 6.53 × 10 -5 or less.

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