JP2021116112A - Polyester container and polyester preform - Google Patents

Abstract

To provide a polyester container that can be crushed easily.SOLUTION: A polyester container is composed of polyester. When different five sites in the polyester container are measured by TG-DTA, a standard deviation of a thermal degradation initiation temperature is 2.0°C or higher and 5.0°C or lower.SELECTED DRAWING: Figure 2

Description

The present invention relates to a polyester container and a polyester preform used in the manufacture of the polyester container.

Polyesters such as polyethylene terephthalate have excellent mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency, etc., and are inexpensive, so they are widely used in the manufacture of containers for filling beverages, etc. There is.

By the way, polyester containers are generally discarded and collected after their use. At this time, it is desired that the polyester container is crushed so as not to be bulky and the volume is reduced as much as possible. However, polyester containers have excellent mechanical strength and may not be easily crushed.

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 can be easily crushed.
Another object of the present invention is to provide a polyester preform used for manufacturing this polyester container.

The present invention is a polyester container made of polyester.
This is a polyester container in which the standard deviation of the thermal decomposition start temperature is 2.0 ° C. or higher and 5.0 ° C. or lower when five different points in the polyester container are measured by TG-DTA.

In one embodiment, the polyester container has a first layer and a second layer constituting an inner layer, the first layer is made of virgin polyester, and the second layer is made of recycled polyester. ing.

In one embodiment, the polyester container further has a third layer constituting an outer layer, the third layer being composed of virgin polyester.

In one embodiment, the polyester container comprises a mouth, a neck, a shoulder, a body, and a bottom, the first layer being provided in the content filling area.

In one embodiment, the polyester container includes a mouth, a neck, a shoulder, a body, and a bottom, and a first layer is provided from the upper end to the bottom of the mouth.

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

In one embodiment, the thickness of the cross section of the polyester container is 0.05 mm or more and 0.54 mm or less.

The present invention is a polyester preform for producing the above polyester container.
Polyester preform that polyester preform is composed of polyester.

According to the present invention, it is possible to provide a polyester container that can be easily crushed.
Further, it is possible to provide a polyester preform used for manufacturing this polyester container.

It is a chart of TG-DTA measurement of the polyester container of Example 1. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester container of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester container of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester container of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester container of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester container of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester container of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester preform of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester preform of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester preform of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester preform of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester preform of this invention. It is a schematic semi-cross-sectional view which shows one Embodiment of the polyester preform of this invention.

<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 the dicarboxylic acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecandioic acid, eicosandionic acid, pimelliic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, and adamantan. Dicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendandicarboxylic acid, anthracendicarboxylic acid, phenanthrangecarboxylic acid, 9,9'-bis Examples thereof include (4-carboxyphenyl) fluoric acid and ester derivatives thereof.
Examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. Diethanol, decahydronaphthalene methanol, decahydronaphthalene methanol, norbornan dimethanol, norbornan diethanol, tricyclodecane dimethanol, tricyclodecaneethanol, tetracyclododecanemethanol, tetracyclododecanediethanol, decalin dimethanol, decalin diethanol, 5 -Methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis (4-hydroxy) Cyclohexylpropane), 2,2-bis (4- (2-hydroxyethoxy) cyclohexyl) propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamandiol , Paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, pentaerythritol and the like.
The polyester is preferably polyethylene terephthalate, which is a copolymer of terephthalic acid and ethylene glycol, or modified polyethylene terephthalate, to which a copolymerization monomer is added.

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

In the polyester container of the present invention, the standard deviation of the thermal decomposition start temperature is 2.0 ° C. or higher and 5.0 ° C. when five different points in the polyester container are measured by thermogravimetric-differential thermal analysis (TG-DTA). It is characterized by the following. As a result, the polyester container can be easily crushed. The reason is not clear, but I guess it is as follows.
It is known that the thermal decomposition start temperature of a polymer differs depending on the molecular weight and the three-dimensional structure even if the raw material monomer is the same, and the mechanical strength of the polymer differs depending on the molecular weight and the three-dimensional structure. That is, polymers having different thermal decomposition start temperatures have different mechanical strengths even if the raw material monomers are the same. When the polyester container is crushed, it is considered that the deformation starts from a part of the container where the mechanical strength is relatively low, and the stress is concentrated in this part. Therefore, it is considered that those having different mechanical strengths in the container can be crushed more easily than those having uniform mechanical strength in the container.
In the polyester container of the present invention, by setting the standard deviation of the thermal decomposition start temperature measured at five different points in the polyester container to 2.0 ° C. or higher, the points having different mechanical strengths are scattered in the polyester container. As a result, it is considered that it can be easily crushed.
Further, by setting the standard deviation of the thermal decomposition start temperature to 5.0 ° C. or lower, the strength required for the polyester container can be maintained.
In the polyester container of the present invention, the standard deviation of the thermal decomposition start temperature is preferably 2.0 ° C. or higher and 4.5 ° C. or lower, and more preferably 2.5 ° C. or higher and 4.0 ° C. or lower.

The thermal decomposition start temperature in the polyester container of the present invention is measured by thermogravimetric-differential thermal analysis (TG-DTA).
To measure the thermal decomposition start temperature, first, a sample of about 6 to 8 mg of a part of a polyester container is weighed in an aluminum pan. Subsequently, the sample is held at 30 ° C. for 10 minutes under an air flow of 175 ml / min, and then the temperature is raised to 600 ° C. at a temperature rise temperature of 10 ° C./min. As shown in FIG. 1, the temperature at the intersection of the tangent line of the TG curve from 30 ° C. to 300 ° C. and the tangent line of the inflection point of the TG curve whose weight decreases sharply on the high temperature side is defined as the thermal decomposition start temperature. .. As the apparatus, DTA-60A manufactured by Shimadzu Corporation can be used.
The thermal decomposition start temperature is measured by TG-DTA in five different samples in the polyester container, and the standard deviation is calculated from the following formula (I).

In the polyester container of the present invention, when five different points in the polyester container are measured, the average value of the thermal decomposition start temperature is preferably 380 ° C. or higher and 405 ° C. or lower, and is 385 ° C. or higher and 400 ° C. or lower. Is more preferable. The average value of the thermal decomposition start temperature can be measured by the above-mentioned thermogravimetric-differential thermal analysis (TG-DTA).

In one embodiment, the polyester in the polyester container comprises recycled polyester. This makes it possible to further improve the environmental load reduction property of the polyester container.
"Recycled polyester" refers to chemical recycled polyester or mechanical recycled polyester.
Chemically recycled polyester refers to polyester obtained by decomposing a polyester container to the monomer level and polymerizing it again.
Mechanical recycled polyester is a polyester container that is sorted, crushed, and washed to remove contaminants and foreign substances, and flakes are obtained. The flakes are further treated at high temperature and reduced pressure for a certain period of time to remove contaminants inside the resin. Refers to the polyester obtained by doing so.

In one embodiment, the polyester in the polyester container comprises a virgin polyester. In the present invention, the "virgin polyester" refers to a polyester that has not been recycled as described above, that is, an unused polyester.
Polyester containers are used not only for preserving beverages but also for preserving non-food products (for example, pesticides and machine oils). When the polyester container used for storage of such non-food is recycled and the removal of pollutants by washing is insufficient, the pollutants are added to the filled contents in the polyester container using recycled polyester. May elute. Therefore, the hygiene of the polyester container can be improved by including the virgin recycled polyester in the polyester of the polyester container.
Further, the polyester in the polyester container may contain recycled polyester and virgin polyester.

When the polyester container of the present invention contains recycled polyester, the content of the recycled polyester is preferably 30 parts by mass or more and 95 parts by mass or less with respect to 100 parts by mass of the total amount of the resin material contained in the polyester container. It is more preferably parts by mass or more and 80 parts by mass or less, and further preferably 60 parts by mass or more and 80 parts by mass or less.
By setting the content of the recycled polyester to 30 parts by mass or more with respect to 100 parts by mass of the total amount of the resin material contained in the polyester container, the environmental load reduction property of the polyester container can be further improved.
By setting the content of the recycled polyester to 95 parts by mass or less with respect to 100 parts by mass of the total amount of the resin material contained in the polyester container, the hygiene of the polyester container can be further improved. Further, when the polyester container includes the second layer as described later, it is possible to prevent the recycled polyester from being exposed to the first layer side or the third layer side in the production of the polyester preform.

The polyester may be polymerized using a polymerization catalyst as long as the characteristics of the present invention are not impaired. Examples of the polymerization catalyst include manganese catalysts, titanium catalysts, aluminum catalysts, lithium catalysts, germanium catalysts, antimony catalysts and the like.
When the polyester container of the present invention is filled with the heated contents, or when the polyester container is heated after the contents are filled, it is preferable to polymerize using a catalyst other than the antimony catalyst. This makes it possible to prevent the elution of antimony into the contents.

Examples of the manganese catalyst include fatty acid manganese salts such as manganese acetate, manganese carbonate, manganese chloride, acetylacetonate salt of manganese, manganese hydroxide and the like.
Examples of the titanium catalyst include tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate, tetracyclohexyl titanate, and tetraphenyl titanate. , Titanium alkoxide such as tetrabenzyl titanate, Titanium oxide obtained by hydrolysis of titanium alkoxide, Titanium acetate, Titanium oxalate, Titanium potassium oxalate, Titanium oxalate, Potassium titanate, Sodium titanate, Titanate-water Aluminum oxide mixture, titanium chloride, titanium chloride-aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluoride, cobalt hexafluoride, manganese hexafluoride, ammonium hexafluoride and Examples include titanium acetylacetonate.
Examples of the aluminum catalyst include aluminum trisacetylacetone, aluminum monoacetylacetonate bis (ethylacetate acetate), ethylacetacetate aluminum diisopropylate, and the like.
Examples of the lithium catalyst include ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium and phenyllithium.
Examples of the germanium catalyst include germanium dioxide, germanium tetroxide, germanium tetramethoxyde, germanium tetraethoxydo, germanium tetrapropoxide, germanium tetrabutoxide, germanium tetrapentoxide and germanium tetrahexoxide.
Examples of the antimony catalyst include antimony trioxide, antimony pentoxide, antimony acetate, triphenylantimony, antimony glycol and the like.

To the extent that the properties of the present invention are not impaired, the polyester container may contain an additive, for example, an oxygen absorber, a gas barrier resin (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6)). Polyamide), plasticizers, UV stabilizers, antioxidants, color inhibitors, matting agents, deodorants, flame retardants, weatherproofing agents, antistatic agents, thread friction reducing agents, slip agents, mold release agents, etc. , Antioxidants, ion exchangers, and colorants.

The polyester container of the present invention may be provided with a thin-film film over the entire inner surface of the container. Thereby, the gas barrier property of the polyester container can be improved.

Examples of the vapor deposition film include metals such as aluminum, inorganic oxides such as aluminum oxide, silicon oxide, magsium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide, and hexamethyldisiloxane. Examples thereof include a vapor-deposited film composed of a hard carbon film such as an organic silicon compound and a DLC (Diamond Like Carbon) film.
Note that the hard carbon film formed of DLC film, i carbon film or hydrogenated amorphous carbon film (a-C: H) and is also of the hard carbon film called, that the amorphous carbon film was mainly SP ³ bond Is.

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

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

FIG. 2 is a schematic semi-cross-sectional view showing an embodiment of the 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.

In one embodiment, as shown in FIG. 2, the mouth portion 11 includes a screw portion 16 to which a cap is screwed, a turnip 17 under the screw portion 16, and a support ring 18 under the turnip 17.

In one embodiment, as shown in FIG. 2, the neck portion 12 is located between the support ring 18 and the shoulder portion 13 and has a substantially cylindrical shape having a substantially uniform diameter. Further, the shoulder portion 13 has a cylindrical shape in which the diameter gradually increases from the neck portion 12 side to the body portion 14 side.

In one embodiment, the torso 14 is located between the shoulders 13 and the bottom 15, as shown in FIG. Further, the body portion 14 includes a panel portion 21 as shown in FIG. With such a configuration, it is possible to prevent the container from being deformed due to an increase or decrease in the internal pressure when the polyester container is filled with the heated contents or when the polyester container is heated after the contents are filled.

In one embodiment, as shown in FIG. 2, the bottom portion 15 includes a recessed portion 19 located at the center and a ground contact portion 20 provided around the depressed portion 19, and the ground contact portion 20 includes a body portion 14 and a body portion 14 in the ground contact portion 20. It is connected. With such a configuration, it is possible to prevent the container from being deformed due to an increase or decrease in the internal pressure when the polyester container is filled with the heated contents or when the polyester is heated after the contents are filled.
In one embodiment, the “bottom” means a portion inside from the ground contact portion when the polyester container is made to stand on its own.

The polyester container of the present invention may be composed of a single layer or multiple layers of two or more layers, or may be composed of a combination of a single layer and multiple layers.
Hereinafter, an example of the embodiment in which the polyester container of the present invention has a multi-layer structure will be described with reference to FIGS. 3 to 7.

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. 3 and 4, and the first layer 22 constitutes an inner layer.

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 the circle A of FIGS. 5 to 7, and is the first layer. 22 constitutes an inner layer, and a third layer 24 constitutes an 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. 5 and 6).
Further, the second layer 23 may be provided from a part of the polyester container, for example, from the lower end of the mouth portion 11 to the bottom portion 15 (see FIG. 7). When the first layer 22 and the third layer 24 are made of the same material, as shown in FIG. 7, these layers become a single layer at a place where the second layer 23 is not provided.

The details of the mouth portion 11, the neck portion 12, the shoulder portion 13, the body portion 14, the bottom portion 15, the screw portion 16, the turnip 17, the support ring 18, the recessed portion 19, the ground contact portion 20, and the panel portion 21 have been described above. , The description is omitted here.

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 setting the capacity / weight of the polyester container to 5 mL / g or more, the blow moldability of the polyester container can be improved, the amount of polyester used can be prevented from becoming excessive, and the discarded polyester can be prevented. Since the amount can be reduced, the reduction of environmental load can be further improved.
Further, the strength of the polyester container can be improved by setting the capacity / weight of the polyester container to 50 mL / g or less.

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 setting the cross-sectional thickness to 0.05 mm or more, the strength of the polyester container can be further improved.
Further, by setting the cross-sectional thickness to 0.54 mm or less, the blow moldability of the polyester container can be improved. In addition, it is possible to prevent the amount of polyester used from becoming excessive, and it is possible to reduce the environmental load.
The thickness of the cross section of the polyester container means, for example, a portion of the body of the polyester container where the thickness of the cross section is the thinnest.

(1st layer)
In one embodiment, the first layer included in the polyester container of the present invention is made of the above-mentioned virgin polyester. As a result, even when recycled polyester is used for the polyester container, it is possible to prevent the recycled polyester from coming into contact with the contents, and it is possible to improve the hygiene of the polyester container.

The virgin polyester constituting the first layer may be polymerized using the above-mentioned polymerization catalyst as long as the characteristics of the present invention are not impaired.
When the polyester container of the present invention is filled with heated contents, or in the case of a polyester container which is heated after filling the contents, the virgin polyester of the first layer is polymerized using a catalyst other than the antimony catalyst. Is preferable. This makes it possible to prevent the elution of antimony into the contents.

To the extent that the properties of the present invention are not impaired, the first layer may contain additives, for example, oxygen absorbers, gas barrier resins (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6). ) Etc. Polyamide) Plasticizer, UV stabilizer, Color inhibitor, Matte agent, Deodorant, Flame retardant, Weatherproof agent, Antistatic agent, Thread friction reducer, Slip agent, Oxygen scavenger, Antioxidant , Ion exchangers, and colored pigments.

In one embodiment, the first layer of the polyester container is provided in the content filling region. In the present invention, the "content filling region" means a region where the content and the polyester container are in contact with each other in a state where the polyester container is filled with the content and is 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 portion to the bottom portion 15.
By providing the first layer from a position 5 to 70 mm below the upper end of the mouth to the bottom, the content filling area can be covered by the first layer, even when recycled polyester is used for the polyester container. , It is possible to prevent the recycled polyester from coming into contact with the contents, and it is possible to further improve the hygiene of the polyester container.
Further, by providing the first layer from a position 5 to 70 mm below the upper end of the mouth portion to the bottom portion, it is possible to effectively prevent cracks in the mouth portion during capping by an automatic machine. Can be done.

In one embodiment, the first layer of the polyester container is provided from a position 70 mm below the upper end of the mouth portion to the bottom portion.
Further, it is preferable that the first layer is provided from a position 15 mm below the upper end of the mouth portion to the bottom portion. As a result, the content filling area can be covered by the first layer, and even when recycled polyester is used for the polyester container, it is possible to prevent the recycled polyester from coming into contact with the contents, and the hygiene of the polyester container can be improved. Can be improved further.
Further, in the polyester container of the present invention, it is more preferable that the first layer is provided from the upper end to the bottom of the mouth portion. As a result, it is possible to further reduce the contact of recycled polyester with the contents even when the polyester is stored in a heated state while being laid on its side in a vending machine or the like, and the hygiene of the polyester container is further improved. be able to.

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 0.025 mm or more and 0.1 mm or less. Is even more preferable.
By setting the thickness of the first layer to 0.01 mm or more, it is possible to effectively prevent the recycled polyester from coming into contact with the contents even when the recycled polyester is used in the polyester container.
Further, 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 property of the polyester container can be further improved.
The thickness of the first layer means, for example, a portion of the body of the polyester container where the thickness of the first layer is the thinnest.

(2nd layer)
In one embodiment, the second layer of the polyester container of the present invention is made of the recycled polyester described above. This makes it possible to further improve the environmental load reduction property of the polyester container.

The recycled polyester constituting the second layer may be polymerized using the above-mentioned polymerization catalyst as long as the characteristics of the present invention are not impaired.

As long as the properties of the present invention are not impaired, the second layer may contain an additive, for example, an oxygen absorber, a gas barrier resin (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6). ) Etc. Polyamide) Plasticizer, UV stabilizer, Color inhibitor, Matte agent, Deodorant, Flame retardant, Weatherproof agent, Antistatic agent, Thread friction reducer, Slip agent, Oxygen scavenger, Antioxidant , Ion exchangers, and colored pigments.

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 0.1 mm or more and 0.22 mm or less. Is even more preferable.
By setting the thickness of the second layer to 0.04 mm or more, the environmental load reduction property of the polyester container can be further improved.
Further, 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 in the production of the polyester preform.
The thickness of the second layer means, for example, a portion of the body of the polyester container where the thickness of the second layer is the thinnest.

(Third layer)
In one embodiment, the third layer included in the polyester container of the present invention is made of the above-mentioned virgin polyester. With such a configuration, the heat resistance and strength of the polyester container can be improved.

The virgin polyester constituting the third layer may be polymerized using the above-mentioned polymerization catalyst as long as the characteristics of the present invention are not impaired. Further, the third layer may be made of the same material as the first layer.

As long as the properties of the present invention are not impaired, the third layer may contain an additive, for example, an oxygen absorber, a gas barrier resin (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6). ) Etc. Polyamide) Plasticizer, UV stabilizer, Color inhibitor, Matte agent, Deodorant, Flame retardant, Weatherproof agent, Antistatic agent, Thread friction reducer, Slip agent, Oxygen scavenger, Antioxidant , Ion exchangers, and colored pigments.

The thickness of the third layer in the polyester container is preferably 0.01 mm or more and 0.1 mm or less, and preferably 0.025 mm or more and 0.05 mm or less.
By setting the thickness of the third layer to 0.01 mm or more, the heat resistance and strength of the polyester container can be further improved.
Further, 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 property of the polyester container can be further improved.
The thickness of the third layer means, for example, a portion of the body of the polyester container where the thickness of the third layer is the thinnest.

<Polyester preform>
The polyester preform of the present invention is used for manufacturing a polyester container.
The polyester preform of the present invention is made of polyester.

As the polyester constituting the polyester preform of the present invention, the same polyester as the polyester in the polyester container described above can be used.

To the extent that the properties of the present invention are not impaired, the polyester preform may contain additives, for example, oxygen absorbers, gas barrier resins (nylon 6, nylon 6, 6 and polymethoxylylen adipamide (MXD6). ) Etc. Polyamide) Plasticizer, UV stabilizer, Color inhibitor, Matte agent, Deodorant, Flame retardant, Weatherproof agent, Antistatic agent, Thread friction reducer, Slip agent, Oxygen scavenger, Antioxidant , Ion exchangers, and colored pigments.

FIG. 8 is a schematic semi-cross-sectional view showing an 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.
In one embodiment, as shown in FIG. 8, the mouth portion 31 corresponds to the mouth portion 11 of the polyester container 10 described above, and has substantially the same shape as the mouth portion 11. Further, in one embodiment, the body portion 32 corresponds to the neck portion 12, the shoulder portion 13 and the body portion 14 of the polyester container 10 described above, and has a substantially cylindrical shape. Further, in one embodiment, the bottom portion 33 corresponds to the bottom portion 15 of the polyester container 10 described above, and has a substantially hemispherical shape.
Further, in one embodiment, as shown in FIG. 8, the mouth portion 31 includes a screw portion 34 to which the cap is screwed, a turnip 35 under the screw portion 34, and a support ring 36 under the turnip 35.

The polyester preform of the present invention may be composed of a single layer or multiple layers of two or more layers, or may be composed of a combination of a single layer and multiple layers.
An example of an embodiment in which the polyester preform of the present invention has a multi-layer structure will be described with reference to FIGS. 9 to 13.

In one embodiment, the polyester preform 30 of the present invention has a first layer 37 and a second layer 38, as shown in FIGS. 9 and 10, and the first layer 37 constitutes an inner layer. ..

In one embodiment, the polyester preform 30 of the present invention has a first layer 37, a second layer 38, and a third layer 39, as shown in FIGS. 11 to 13. The inner layer is formed, and the third layer 39 constitutes 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. 11 and 12).
Further, the second layer 38 may be provided from 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. 13). When the first layer 37 and the third layer 39 are made of the same material, as shown in FIG. 13, these layers become a single layer at a place where the second layer 38 is not provided.

Since the details of the mouth portion 31, the body portion 32, the bottom portion 33, the screw portion 34, the turnip 35, and the support ring 36 have been described above, the description thereof will be omitted here.

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 thickness of the cross section in the above range, the polyester container as described above can be obtained.
The thickness of the cross section of the polyester preform means, for example, a portion of the body of the polyester preform where the thickness of the cross section is the thinnest.

(1st layer)
In one embodiment, as shown in FIGS. 9 and 11, when the distance from the lower end of the bottom portion 33 to the upper end of the mouth portion 31 is L, the first layer 37 is 0 from the lower end. It is provided in the range of .4 L or more and 0.97 L or less.
Since the first layer 37 is provided in 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 content-filled area is covered by the first layer. It is possible to prevent the recycled polyester from coming into contact with the contents even when the recycled polyester is used, and the hygiene of the polyester container can be further improved.
Further, since the first layer 37 is provided in a range of 0.97 L or less from the lower end of the bottom portion 33, when the polyester preform is blow-molded into a polyester container, when capping is performed by an automatic machine. , It is possible to effectively prevent the mouth from being cracked.

In one embodiment, the first layer may be provided from the lower end of the bottom to the upper end of the mouth, or may be provided from the lower end of the bottom to the lower end of the mouth.

As the material constituting the first layer in the polyester preform, the same material as the material constituting the first layer in the polyester container can be used.

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. When the polyester preform includes the 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 0.1 mm or more and 1.0 mm or less. Is more preferable. 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, a portion of the body of the polyester preform where the thickness of the first layer is the thinnest.

(2nd layer)
As the material forming the second layer in the polyester preform, the same material as the material forming the second layer in the polyester container can be used.

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. When the polyester preform includes the 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 1.6 mm or more and 3.4 mm or less. Is preferable. 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, a portion of the body of the polyester preform where the thickness of the second layer is the thinnest.

(Third layer)
As the material constituting the third layer in the polyester preform, the same material as the material constituting the third layer in the polyester container can be used.

The thickness of the third layer in the polyester preform is preferably 0.05 mm or more and 1.5 mm or less, and 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, a portion of the body of the polyester preform where the thickness of the third layer is the thinnest.

<Manufacturing method of polyester container>
In one embodiment, the polyester container shown in FIG. 2 can be manufactured by producing a polyester preform by injection molding the above-mentioned polyester and then blow molding the polyester preform.

In one embodiment, the polyester container shown in FIGS. 3 and 4 produces a polyester preform by co-injection molding the materials constituting the first layer and the second layer described above, and blow molding the polyester preform. By doing so, the polyester container of the present invention can be manufactured. The formation position of each layer can be adjusted by injection molding conditions such as resin temperature.

Further, the polyester container shown in FIG. 3 and the like can also be manufactured by using two-color molding or insert molding.
Further, in the polyester container shown in FIG. 3 and the like, virgin polyester is injection-molded into the internal mold to form the first layer, the internal mold is retracted, and a gap is provided between the internal mold and the first layer. Is provided, and recycled polyester is injection-molded in the gap to form a second layer.

In one embodiment, the polyester container shown in FIGS. 5 to 7 prepares a preform by co-injection molding the materials constituting the first layer, the second layer and the third layer described above. The polyester container of the present invention can be manufactured by blow molding.
When the second layer is formed as a part of the preform, it is preferable to use the hot runner nozzle disclosed in Japanese Patent Application Laid-Open No. 2008-94454.

Further, the polyester container shown in FIG. 5 and the like can also be manufactured by using three-color molding or insert molding.
Further, in the polyester container shown in FIG. 5 and the like, virgin polyester is injection-molded in the internal mold to form a first layer, the internal mold is retracted, and a gap is provided between the internal mold and the first layer. Is provided, recycled polyester is injection-molded in this gap, a second layer is formed, the internal mold is retracted, a gap is provided between the internal mold and the first layer and the second layer, and a virgin is provided in this gap. It can be produced by injection molding polyester to form a third layer.

The polyester container of the present invention having the range of the standard deviation of the thermal decomposition start temperature can be produced by appropriately controlling the conditions and the like at the time of injection molding in the production of the polyester preform. Examples of the conditions include the rotation speed and temperature of the screw when the molten polyester is sent out by the screw, the temperature and supply speed of the nozzle for supplying the molten polyester to the mold, the temperature of the mold, and the like.

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

(Measurement of thermal decomposition start temperature by TG-DTA and calculation of standard deviation)
The thermal decomposition start temperature of the polyester container and the polyester pellet was measured by TG-DTA. The number of samples to be measured is five. As the apparatus, DTA-60A manufactured by Shimadzu Corporation was used.
For the measurement, first, at the middle portion in the height direction of the polyester container, five different points in the circumferential direction were cut, and five square samples having a piece of about 0.4 cm were prepared. About 7 mg of each of the 5 samples was weighed into an aluminum pan. Subsequently, the sample was held at 30 ° C. for 10 minutes under an air flow of 175 ml / min, and then the temperature was raised to 600 ° C. at a temperature rise temperature of 10 ° C./min. As shown in FIG. 1, the temperature at the intersection of the tangent line of the TG curve from 30 ° C. to 300 ° C. and the tangent line of the inflection point of the TG curve whose weight decreases sharply on the high temperature side is defined as the thermal decomposition start temperature. .. The thermal decomposition start temperature of the sample shown in FIG. 1 was 399.52 ° C.
The thermal decomposition start temperature was measured by TG-DTA in five different samples in the polyester container, and the standard deviation was calculated from the following formula (I).

In the case of polyester pellets, one grain was weighed in the same manner, and the thermal decomposition start temperature was measured by the same method as described above. rice field.

Example 1
Using an injection molding machine, a polyester preform having a mouth, a body, and a bottom was produced from mechanically recycled polyester having a thermal decomposition start temperature of 395.5 ° C. The mouth of the polyester preform is provided with a male thread, a turnip and a support ring in this order from the upper end of the mouth.
The thickness of the cross section of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g.

Next, the polyester preform was heated to 110 ° C. and biaxially stretched and blow molded in a blow molding die to obtain a polyester container having the shape shown in FIG. 2 and having an internal volume of 500 mL. The thickness of the cross section of the body of the polyester container was 0.32 mm.

Next, according to the above method, the thermal decomposition start temperature was measured and the standard deviation was calculated by TG-DTA. The pyrolysis start temperature was 396.1 ° C., and the standard deviation of the pyrolysis start temperature was 3.1 ° C.

Example 2
A polyester preform was produced in the same manner as in Example 1 except that a mechanically recycled polyester having a thermal decomposition start temperature of 397.7 ° C., which was different from Example 1, was used. The thickness of the cross section of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g. Further, using the polyester preform of this example, a polyester container was prepared in the same manner as in Example 1, and the thermal decomposition start temperature was measured. The thickness of the cross section of the body of the polyester container was 0.32 mm. The pyrolysis start temperature was 396.3 ° C., and the standard deviation of the pyrolysis start temperature was 3.3 ° C.

Example 3
A mechanically recycled polyester having a pyrolysis start temperature of 395.5 ° C. and a non-recycled polyester having a pyrolysis start temperature of 401.8 ° C. were prepared.
These are co-injected using an injection molding machine, and the multilayer (2) shown in FIG. 10 includes a first layer made of polyester that has not been recycled and a second layer made of mechanically recycled polyester. Seed 2 layers) Preform was created.
The amount of mechanically recycled polyester used was adjusted to be 80 parts by mass with respect to 100 parts by mass of the resin material constituting the multilayer preform.
The thickness of the cross section of the body of the multilayer preform was 3.5 mm, and the basis weight was 22 g.

Next, the multilayer preform was heated to 110 ° C. and biaxially stretched and blow molded in a blow molding die to obtain a multilayer container having the shape shown in FIG. 4 and having an internal volume of 500 mL. The thickness of the cross section of the body of the polyester container was 0.32 mm.

Next, the thermal decomposition start temperature was measured in the same manner as in Example 1. The pyrolysis start temperature was 394.5 ° C., and the standard deviation of the pyrolysis start temperature was 2.9 ° C.

Example 4
A mechanically recycled polyester having a pyrolysis start temperature of 395.5 ° C. and a non-recycled polyester having a pyrolysis start temperature of 401.8 ° C. were prepared.
These are co-injected using an injection molding machine and composed of a first layer composed of non-recycled polyester, a second layer composed of mechanically recycled polyester, and non-recycled polyester. A multi-layer (2 types, 3 layers) preform shown in FIG. 12 having a third layer was prepared.
The amount of mechanically recycled polyester used was adjusted to be 50 parts by mass with respect to 100 parts by mass of the resin material constituting the multilayer preform.
The thickness of the cross section of the body of the multilayer preform was 3.5 mm, and the basis weight was 22 g.

Next, the multilayer preform was heated to 110 ° C. and biaxially stretched and blow molded in a blow molding die to obtain a multilayer container having the shape shown in FIG. 6 and having an internal volume of 500 mL. The thickness of the cross section of the body of the polyester container was 0.32 mm.

Next, the thermal decomposition start temperature was measured in the same manner as in Example 1. The pyrolysis start temperature was 389.4 ° C., and the standard deviation of the pyrolysis start temperature was 2.5 ° C.

Comparative Example 1
A polyester preform was produced in the same manner as in Example 1 except that a non-recycled polyester having a thermal decomposition start temperature of 401.8 ° C. was used. The thickness of the cross section of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g. Further, using the polyester preform of this comparative example, a polyester container was prepared in the same manner as in Example 1, and the thermal decomposition start temperature was measured. The thickness of the cross section of the body of the polyester container was 0.32 mm. The pyrolysis start temperature was 395.4 ° C., and the standard deviation of the pyrolysis start temperature was 0.3 ° C.

Comparative Example 2
A polyester preform was produced in the same manner as in Example 1 except that a mechanically recycled polyester having a thermal decomposition start temperature of 381.0 ° C. was used. The thickness of the cross section of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g. Further, using the polyester preform of this comparative example, a polyester container was prepared in the same manner as in Example 1, and the thermal decomposition start temperature was measured. The thickness of the cross section of the body of the polyester container was 0.32 mm. The thermal decomposition start temperature was 377.4 ° C., and the standard deviation of the thermal decomposition start temperature was 1.0 ° C.

<< Evaluation of ease of crushing the container >>
The body of the container obtained in the above Examples and Comparative Examples was crushed by hand, and the easiness of crushing was evaluated based on the following evaluation criteria. There are five participants in the evaluation.
The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: Compared with Comparative Example 1, it is easier to crush.
B: Ease of crushing is the same as that of Comparative Example 1.

All five participants in the evaluation obtained the evaluation results in the above table, and in the above-mentioned Examples and Comparative Examples, the polyester container in which the standard deviation of the thermal decomposition start temperature was within the range of the present invention was improved in the ease of crushing the container. It can be seen that the polyester container has a high environmental load reduction property.

10: Polyester container 11: Mouth 12: Neck 13: Shoulder 14: Body 15: Bottom 16: Screw 17: Cabra 18: Support ring 19: Depressed 20: Ground 21: Panel 22: First layer 23: 2nd layer 24: 3rd layer 30: Polyester preform 31: Mouth 32: Body 33: Bottom 34: Screw 35: Cabra 36: Support ring 37: 1st layer 38: 2nd layer 39: 1st 3 layers

Claims (8)

A polyester container made of polyester
A polyester container in which the standard deviation of the thermal decomposition start temperature is 2.0 ° C. or higher and 5.0 ° C. or lower when five different points in the polyester container are measured by TG-DTA. The polyester container has a first layer and a second layer forming an inner layer, and has a second layer.
The first layer is made of virgin polyester.
The polyester container according to claim 1, wherein the second layer is made of recycled polyester. The polyester container further has a third layer constituting an outer layer.
The polyester container according to claim 2, wherein the third layer is made of virgin polyester. The polyester container includes a mouth, a neck, a shoulder, a body, and a bottom.
The polyester container according to claim 2 or 3, wherein the first layer is provided in a content filling region. The polyester container includes a mouth, a neck, a shoulder, a body, and a bottom.
The polyester container according to claim 2 or 3, wherein the first layer is provided from the upper end of the mouth portion to the bottom portion. The polyester container according to any one of claims 1 to 5, wherein the polyester is polyethylene terephthalate or modified polyethylene terephthalate. The polyester container according to any one of claims 1 to 6, wherein the thickness of the cross section of the polyester container is 0.05 mm or more and 0.54 mm or less. A polyester preform for producing the polyester container according to any one of claims 1 to 7.
A polyester preform in which the polyester preform is made of polyester.

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