JP7015486B1 - Polyester container and polyester preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester container having a reduced yellowness and to easily remove a bluing agent when mechanically recycled. The present invention is a polyester container including a mouth, a neck, a shoulder, a body, and a bottom, which includes a mechanically recycled polyester and a brewing agent, and the mechanically recycled polyester. The content of the brewing agent is 0.0001% by mass or more and 0.00125% by mass or less with respect to the content of the brewing agent, and the brewing agent has a dye having a vaporization temperature of 230 ° C. or less at 15 mbar, and the mechanical A polyester container in which the b * value of recycled polyester in the L * a * b * color system is +3.0 or more. [Selection diagram] Fig. 1

Description

The present invention relates to polyester containers and polyester preforms.

In recent years, attempts have been made to recycle plastic products in order to reduce the environmental burden. For example, used polyester containers such as PET bottles are being recycled. Recycled polyester obtained by recycling polyester containers is used in various products. As such recycled polyester, chemical recycled polyester and mechanical recycled polyester are known.

Chemically recycled polyester is a polyester obtained by chemically decomposing a used polyester container, returning it to a monomer unit, purifying it, and repolymerizing it. Therefore, the chemically recycled polyester has physical characteristics and properties comparable to those of the virgin polyester. However, chemically recycled polyester has a problem that the recycling cost is high. Here, the virgin polyester is a polyester produced by a conventional method from a dicarboxylic acid and a diol made from petroleum or the like.

On the other hand, mechanically recycled polyester is a used polyester container that is crushed and washed to remove contaminants and foreign substances to obtain flakes, and the flakes are further treated at high temperature and reduced pressure for a certain period of time to treat the contaminants inside the resin. It is a polyester obtained by removing the above, or it is obtained by pelletizing the washed flakes and then treating the pellets at a higher temperature and under reduced pressure for a certain period of time to remove contaminants inside the resin. It is polyester. Mechanical recycling is cheaper than chemical recycling because recycled polyester can be obtained without undergoing chemical decomposition. Therefore, from the viewpoint of cost, it is desirable to use mechanical recycled polyester as the recycled polyester.

When flakes and pellets made of mechanically recycled polyester are used in the manufacture of polyester containers, the polyester containers after molding may turn yellow due to the slight amount of impurities remaining in the flakes and pellets.
In order to reduce the yellowness of the resin due to yellowing and make it transparent as described above, in Patent Document 1, a molded product obtained from a resin composition containing recycled polyester is provided with a light brightener, a blue pigment, or the like. It has been proposed to use pigments. Such additives such as fluorescent whitening agents and blue pigments that reduce the yellowness of the resin and make it transparent are generally referred to as brewing agents (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2004-359914 Japanese Unexamined Patent Publication No. 2001-166101

By the way, since flakes and pellets made of mechanically recycled polyester are used in various containers, it is desirable that the additives used in the polyester container before mechanical recycling do not remain in the flakes and pellets. From this point of view, when the polyester container containing the brewing agent is mechanically recycled, it is desirable that the brewing agent is removed from the flakes and pellets made of the obtained mechanically recycled polyester.

Now, the present inventors have noticed that the bluing agent cannot be removed when the polyester container containing the pigment as the bluing agent is mechanically recycled.

Therefore, it is an object of the present invention to provide a polyester container with reduced yellowness and a polyester container from which the bluing agent can be easily removed when mechanically recycled.
Another object of the present invention is to provide a polyester preform used in the manufacture of this polyester container.

The present inventors have found that the above problems can be solved by using a specific dye as a bluing agent.

Therefore, the present invention is a polyester container provided with a mouth portion, a neck portion, a shoulder portion, a body portion, and a bottom portion.
Contains mechanically recycled polyester and bluing agent,
The content of the bluing agent with respect to the content of the mechanically recycled polyester is 0.0001% by mass or more and 0.00125% by mass or less.
The bluing agent is a dye having a vaporization temperature of 230 ° C. or lower at 1500 Pa .
A polyester container in which the B ^* value of the mechanically recycled polyester in the L ^* a ^* b ^* color system is +3.0 or more.

In the polyester container according to the present invention, the bluing agent may be an anthraquinone-based bluing agent.

In the polyester container according to the present invention, the content of the mechanically recycled polyester with respect to the entire polyester constituting the polyester container may be 95% by mass or more.

The polyester container according to the present invention may have a body thickness of 0.05 mm or more and 0.54 mm or less.

In the polyester container according to the present invention, the content may be a colorless and transparent liquid.

The present invention is a polyester preform used in the manufacture of the polyester container.

According to the present invention, it is possible to provide a polyester container having a reduced yellowness and a polyester container capable of easily removing a bluing agent during mechanical recycling.

According to the present invention, it is possible to provide a polyester preform used for manufacturing this polyester container.

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

[Polyester container]
The polyester container according to the present invention contains mechanically recycled polyester and a bluing agent.
As used herein, the "polyester container" is a container containing polyester as a main component. As used herein, the term "main component" means a component that exceeds 50% by mass of the whole. The content of polyester in the polyester container is preferably 70% by mass or more, more preferably 90% by mass or more, and further preferably 99% by mass or more.

As used herein, the term "container" means a molded article that houses an article. Examples of the container include molded parts such as compression molded parts, injection molded parts, blow molded parts and thermoformed parts. Specific containers include, for example, bottles, vials, cups, trays and packs.

As used herein, the term "polyester" means a polymer polymerized by an ester bond. Such polyesters are usually obtained by polycondensing a dicarboxylic acid compound and a diol compound.
Examples of the dicarboxylic acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecandionic 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) fluorenic 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, neopentylglycol, cyclohexanedimethanol, and cyclohexane. Diethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornandimethanol, norbornandiethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindiethanol, decalindiethanol, 5 -Methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis (4-hydroxy) Cyclohexylpropane), 2,2-bis (4- (2-hydroxyethoxy) cyclohexyl) propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamandiol , Paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, pentaerythritol, bis-β-hydroxyethyl terephthalate (BHET) and the like.
In the polyester container according to the present invention, the polyester is preferably polyethylene terephthalate, or a modified polyethylene terephthalate obtained by polymerizing a raw material monomer of polyethylene terephthalate and a copolymerized monomer, and particularly preferably polyethylene terephthalate.

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

Hereinafter, the mechanically recycled polyester and the bluing agent contained in the polyester container according to the present invention will be described.

<Mechanical recycled polyester>
As used herein, "mechanical recycled polyester" refers to used polyester containers that are crushed and washed to remove contaminants and foreign matter, flakes are obtained, and the flakes are further treated at high temperature and reduced pressure for a certain period of time. It is a polyester obtained by removing contaminants inside the resin and pelletizing it, or after pelletizing the washed flakes, the pellets are further treated at high temperature and under reduced pressure for a certain period of time to inside the resin. It is a polyester obtained by removing contaminants.
The mechanically recycled polyester contained in the polyester container according to the present invention is preferably mechanically recycled polyethylene terephthalate.

A small amount of impurities remain in the flakes and pellets made of the mechanically recycled polyester. Such trace impurities are unavoidable impurities that cannot be completely removed even after being treated at high temperature and under reduced pressure for a certain period of time. In the production of polyester containers, flakes and pellets are melted, but if trace impurities are present in the flakes and pellets, the heat of melting causes the polyester to turn yellow. Therefore, the mechanically recycled polyester contained in the polyester container according to the present invention has a yellowish tinge.
The polyester container according to the present invention can reduce the yellowness of the polyester container by containing a bluing agent described later in a specific range. Such a polyester container with reduced yellowness is particularly suitable when the content is a colorless and transparent liquid. The colorless and transparent liquid is not particularly limited, and examples thereof include drinking water and the like.

In the polyester container according to the present invention, the L ^* a ^* b ^* color system b ^* value of the mechanically recycled polyester may be +3.0 or more, +4.0 or more, or +4.5 or more. On the other hand, the L ^* a ^* b ^* color system of the mechanically recycled polyester may have a b ^* value of +20.0 or less, +10.0 or less, or +7.0 or less.
In the present specification, the L ^* a ^* b ^* b ^* value in the color system of mechanically recycled polyester is measured according to JIS Z8722: 2009.
Specifically, mechanically recycled polyester having an arbitrary shape is freeze-crushed to prepare a powder, and this powder is measured by reflected light using a spectrocolorimeter. The measurement conditions are SCE (specular reflection removal), 10 ° field of view, and D65 light source. As the spectrocolorimeter, for example, CMS-35SP manufactured by Murakami Color Technology Research Institute Co., Ltd. can be used.

In the polyester container according to the present invention, the content of the mechanically recycled polyester with respect to the entire polyester constituting the polyester container is preferably 95% by mass or more, more preferably 97% by mass or more, still more preferably 99% by mass or more. Yes, and particularly preferably 99.9% by mass or more. This makes it possible to obtain a polyester container with a further reduced environmental load.
In addition to the mechanically recycled polyester, the polyester container according to the present invention may contain polyesters such as virgin polyester and chemically recycled polyester.

<Bluing agent>
As used herein, the "blueing agent" is an additive that absorbs light in a wavelength region such as orange to yellow in the visible light region and adjusts the hue.
As used herein, the term "visible light region" means a region of 380 nm or more and 780 nm or less.

The brewing agent contained in the polyester container according to the present invention is a dye having a vaporization temperature of 230 ° C. or lower at 1500 Pa . By using such a dye as a bluing agent, the bluing agent can be easily removed when the polyester container is mechanically recycled. This is because, in mechanical recycling, when flakes or pellets are treated under high temperature and reduced pressure for a certain period of time, the brewing agent can be easily removed together with the contaminants inside the resin.
From the viewpoint that the brewing agent can be more easily removed from the flakes or pellets, the vaporization temperature of the dye used as the brewing agent is preferably 225 ° C. or lower, more preferably 220 ° C. or lower at 1500 Pa . ..
On the other hand, the vaporization temperature of the dye used as a bluing agent is preferably 300 ° C. or higher, more preferably 350 ° C. or higher at 1013 25 Pa (atmospheric pressure). By using a dye having a vaporization temperature or higher, the amount of dye released into the atmosphere during the production of the polyester container can be reduced, and the content of the brewing agent in the polyester container after molding can be easily adjusted. ..

In the polyester container according to the present invention, the content of the brewing agent with respect to the mechanically recycled polyester is 0.0001% by mass or more and 0.00125% by mass or less. When the content of the bluing agent is within such a range, the yellowness of the polyester container can be reduced and the polyester container can be made transparent. Further, by setting the content of the bluing agent in such a range, the bluing agent can be easily removed when the polyester container according to the present invention is mechanically recycled.
The content of the bluing agent is preferably 0.00025% by mass or more, and more preferably 0.0004% by mass or more. On the other hand, the content of the bluing agent is preferably 0.001% by mass or less, and more preferably 0.0008% by mass or less.

The bluing agent contained in the polyester container according to the present invention preferably has a maximum absorption peak in a wavelength region of 500 nm or more and 650 nm or less in the visible light region. By using a bluing agent having a maximum absorption peak in such a wavelength region, the yellowness of the polyester container can be efficiently reduced. The bluing agent more preferably has a maximum absorption peak in the wavelength region of 550 nm or more and 600 nm or less in the visible light region.
In the present specification, the maximum absorption peak can be measured by, for example, SPD-M20A (photodiode array detector) manufactured by Shimadzu Corporation. As the solvent for dissolving the bluing agent, for example, acetonitrile can be used.

Examples of the brewing agent as described above include dyes such as anthraquinone-based brewing agents and indigo-based brewing agents.

で表されるアントラキノン環を含有するブルーイング剤である。アントラキノン系ブルーイング剤として、好ましくは、式（２）：

［式（２）中、Ｘ^１はＯＨ、ＮＨＲ^１又はＮＲ^１Ｒ^２を表し、Ｘ^２はＮＨＲ^３又はＮＲ^３Ｒ^４を表し、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、互いに独立して、炭素数１以上６以下の直鎖状又は分枝状アルキル基、又は、炭素数１以上６以下の直鎖状又は分枝状アルキル基で置換されたフェニル基を表す。］
で表される一般式を有する化合物が挙げられる。式（２）中のＸ^１及びＸ^２は、互いに同一でも、異なってもよい。式（２）で表される化合物は、好ましくは、式中のＸ^１及びＸ^２のうち少なくとも１つが、炭素数１以上６以下の直鎖状又は分枝状アルキル基で置換されたフェニル基を有し、より好ましくは、式中のＸ^１又はＸ^２が炭素数１以上６以下の直鎖状又は分枝状アルキル基で置換されたフェニル基を有する。 The anthraquinone-based bluing agent has the formula (1):

It is a bluing agent containing an anthraquinone ring represented by. As an anthraquinone-based bluing agent, the formula (2): is preferable.

[In equation (2), X ¹ represents OH, NHR ¹ or NR ¹ R ² , X ² represents NHR ³ or NR ³ R ⁴ , and R ¹ , R ² , R ³ and R ⁴ are independent of each other. It represents a phenyl group substituted with a linear or branched alkyl group having 1 or more and 6 or less carbon atoms or a linear or branched alkyl group having 1 or more and 6 or less carbon atoms. ]
Examples thereof include compounds having a general formula represented by. X ¹ and X ² in the formula (2) may be the same as or different from each other. The compound represented by the formula (2) preferably has a phenyl group in which at least one of X ¹ and X ² in the formula is substituted with a linear or branched alkyl group having 1 or more and 6 or less carbon atoms. More preferably, it has a phenyl group in which X ¹ or X ² in the formula is substituted with a linear or branched alkyl group having 1 or more and 6 or less carbon atoms.

The anthraquinone-based brewing agent is more preferably a compound represented by the formulas (3) to (5).

The indigo-based brewing agent is a brewing agent containing indoxyl or thioindoxyl.

The brewing agent contained in the polyester container according to the present invention is preferably an anthraquinone-based brewing agent from the viewpoint of heat resistance and solubility (dispersibility), and more preferably has a structure represented by the formula (1). It is at least one kind of brewing agent having, more preferably at least one kind of brewing agent having a structure represented by the formula (2), and even more preferably the formulas (3) to (5). It is at least one kind of brewing agent selected from the group consisting of the compound represented by the above, and particularly preferably the brewing agent represented by the formula (3).

One type of bluing agent may be used alone, or two or more types may be used in combination. Further, in the production of the polyester container according to the present invention, the bluing agent may be used together with an oil component in order to disperse well in the polyester container. Examples of the oil component include ester compounds such as glycerol diacetylmonooleate.
In one embodiment, the brewing agent can be added to the polyester container by using a masterbatch containing the brewing agent and the polyester. The masterbatch may contain the above oil components.
In one embodiment, the brewing agent may be added to the brewing agent during the step of pelletizing the flakes in mechanical recycling.

Hereinafter, an embodiment of the structure of the polyester container according to the present invention will be described by exemplifying FIG.

FIG. 1 is a schematic semi-cross-sectional view showing an embodiment of the polyester container 10 according to the present invention. As shown in FIG. 1, 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.

In one embodiment, as shown in FIG. 1, 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, the neck 12 is located between the support ring 18 and the shoulder 13 as shown in FIG. 1 and has a substantially cylindrical shape with a substantially uniform diameter. Further, in one embodiment, the shoulder portion 13 has a cylindrical shape whose 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, in one embodiment, the body portion 14 includes a panel portion 21 in which the body portion 14 is recessed inward, as shown in FIG. With such a configuration, it is possible to prevent the polyester 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. 1, the bottom portion 15 includes a recessed portion 19 located at the center and a grounding portion 20 provided around the depressed portion 19, and the grounding portion 20 includes a trunk portion 14 and a body portion 14 in the grounding portion 20. It is connected. With such a configuration, it is possible to prevent the polyester 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.

Since the polyester container according to the present invention has a reduced yellowness, the thickness of the polyester container can be increased. This is because even if the thickness of the polyester container is increased, the color of the contents does not easily change when the contents are visually observed from the outside of the polyester container. Therefore, the polyester container according to the present invention can improve the strength of the polyester container while suppressing the influence of the color on the contents. The thickness of the cross section of the body of the polyester container is preferably 0.05 mm or more, more preferably 0.1 mm or more.
On the other hand, from the viewpoint of reducing the amount of the polyester container used, the thickness of the cross section of the body of the polyester container is preferably 0.54 mm or less, more preferably 0.5 mm or less.
The thickness of the cross section of the body of the polyester container means the place where the thickness is the thinnest.

In the polyester container according to the present invention, the ratio of volume to mass (volume / mass) is preferably 5 mL / g or more, more preferably 8 mL / g or more, from the viewpoint of moldability of the polyester container.
On the other hand, the volume / mass is preferably 50 mL / g or less, more preferably 45 mL / g or less, from the viewpoint of the strength of the polyester container.

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

In one embodiment, the polyester container may be provided with a vapor deposition film on its surface. This makes it possible to improve the gas barrier property of the polyester container. The thin-film film may be located on the inner surface or the outer surface of the polyester container, but is preferably located on the inner surface.

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 of the above and a DLC (Diamond Like Carbon) film.
The hard carbon film made of a DLC film is a hard carbon film also called an i-carbon film or a hydrogenated amorphous carbon film (a-C: H) ^, and is an amorphous carbon film mainly composed of SP3 bonds. Is.

The thickness of the vapor-film vapor film is not particularly limited, and may 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 (PVD 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 (CVD methods, CVD methods) such as chemical vapor deposition methods, thermochemical vapor deposition methods, and photochemical vapor deposition methods.
The thickness of the thin-film deposition layer can be measured, for example, in the body of the polyester container, and means a portion where the thickness is the thinnest.

[Polyester preform]
As used herein, the "polyester preform" is a preformed body before blow molding a polyester container.
The polyester preform according to the present invention is used for manufacturing a polyester container according to the present invention. Therefore, the polyester preform according to the present invention contains mechanically recycled polyester and a bluing agent. By making the polyester preform have such a structure, the polyester container according to the present invention can be manufactured.
As the mechanically recycled polyester and the brewing agent contained in the polyester preform according to the present invention, the same ones as those of the polyester container according to the present invention can be used.

Hereinafter, an embodiment of the structure of the polyester preform according to the present invention will be described with reference to FIG.

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

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

The thickness of the cross section of the polyester preform according to the present invention is preferably 1.3 mm or more, more preferably 1.7 mm or more. On the other hand, the thickness of the cross section of the polyester preform in the body is preferably 4.7 mm or less, more preferably 4.0 mm or less.
By setting the thickness of the cross section of the polyester preform in the above range within the above range, the polyester container according to the present invention can be manufactured.
The thickness of the cross section of the body of the polyester preform means the place where the thickness is the thinnest.

The present invention includes the following embodiments.
[1] A polyester container containing mechanically recycled polyester and a bluing agent.
The content of the bluing agent with respect to the content of the mechanically recycled polyester is 0.0001% by mass or more and 0.00125% by mass or less.
A polyester container in which the bluing agent is a dye having a vaporization temperature of 230 ° C. or lower at 1500 Pa .
[2] The polyester container according to [1], wherein the brewing agent is an anthraquinone-based brewing agent.
[3] The polyester container according to [1] or [2], wherein the content of the mechanically recycled polyester with respect to the entire polyester constituting the polyester container is 95% by mass or more.
[4] The mouth, neck, shoulders, torso, and bottom are provided.
The polyester container according to any one of [1] to [3], wherein the body has a thickness of 0.05 mm or more and 0.54 mm or less.
[5] The polyester container according to any one of [1] to [4], wherein the content is a colorless and transparent liquid.
[6] The polyester container according to any one of [1] to [5], wherein the mechanically recycled polyester has a b ^* value of +3.0 or more in the L ^* a ^* b ^* color system.
[7] A polyester preform used for producing the polyester container according to any one of [1] to [6].

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

[Example 1]
Pellet A made of mechanically recycled polyester and pellet B made of a polyethylene terephthalate masterbatch containing an anthraquinone-based brewing agent having the structure of the formula (3) were prepared. The vaporization temperature of the bluing agent is 215 ° C. at 1500 Pa.
First, 97 parts by mass of pellet A and 3 parts by mass of pellet B were dry-blended to obtain a mixture. The content of the bluing agent with respect to the mechanically recycled polyester in the obtained mixture is 0.0005% by mass.
Then, the obtained mixture was melted, and the melt was injected using an injection molding machine to prepare the polyester preform shown in FIG. The thickness 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 blow molding was performed in a blow molding die to prepare a polyester container having an internal volume of 500 mL as shown in FIG. The thickness of the cross section in the body of the polyester container was 0.32 mm.

[Example 2]
The polyester preform shown in FIG. 2 was prepared in the same manner as in Example 1 except that pellet A and pellet B were dry-blended so that the content of the bluing agent in the mechanically recycled polyester was 0.00035% by mass. did. The thickness of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g.

Next, a polyester container was prepared from the polyester preform in the same manner as in Example 1. The thickness of the cross section in the body of the polyester container was 0.32 mm.

[Example 3]
The polyester preform shown in FIG. 2 was prepared in the same manner as in Example 1 except that pellet A and pellet B were dry-blended so that the content of the bluing agent in the mechanically recycled polyester was 0.0002% by mass. did. The thickness of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g.

Next, a polyester container was prepared from the polyester preform in the same manner as in Example 1. The thickness of the cross section in the body of the polyester container was 0.32 mm.

[Comparative Example 1]
The polyester preform shown in FIG. 2 was produced in the same manner as in Example 1 except that only pellet A was used. The thickness of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g.

Next, a polyester container was prepared from the polyester preform in the same manner as in Example 1. The thickness of the cross section in the body of the polyester container was 0.32 mm.

[Comparative Example 2]
Pellets C made of a polyethylene terephthalate masterbatch containing a cobalt-based pigment (cobalt blue) as a bluing agent were prepared.
The polyester preform shown in FIG. 2 was prepared in the same manner as in Example 1 except that pellet A and pellet C were dry-blended so that the content of the bluing agent in the mechanically recycled polyester was 0.0005% by mass. did. The thickness of the body of the polyester preform was 3.5 mm, and the basis weight was 22 g.

Next, a polyester container was prepared from the polyester preform in the same manner as in Example 1. The thickness of the cross section in the body of the polyester container was 0.32 mm.

<< Measurement of color >>
Samples prepared in Examples and Comparative Examples in which only the mouth of the polyester container was cut into small pieces were pre-cooled in liquid nitrogen using a freeze crusher (SPEX, 6870 type Freezer / Mill) for 10 minutes, and then liquid nitrogen was used. Freezing and pulverizing for 10 minutes underneath to obtain a powder. Next, this powder was subjected to L ^* a ^* b ^* L ^* value, a ^* value and L * a * value in the reflected light using a spectrocolorimeter (CMS-35SP, manufactured by Murakami Color Technology Laboratory Co., Ltd.). b ^* The value was measured. The measurement conditions were SCE (specular reflection removal), 10 ° field of view, and D65 light source. The measurement was performed in accordance with JIS Z8722: 2009. The measurement results are shown in Table 1.

<< Measurement of content of bluing agent >>
The polyester containers prepared in Examples and Comparative Examples were crushed to obtain flakes. The flakes were then treated at 230 ° C. and 1500 Pa for 2 hours. The content of the brewing agent contained in the treated flakes was measured by LC-MS (Made by Bruker Japan Co., Ltd., maxis impact) in Examples, and Comparative Example 2 was manufactured by ICP-AES (manufactured by Shimadzu Corporation). , ICPE-9820). The measurement results are shown in Table 1.

It can be seen that the polyester container according to the present invention has a reduced yellowness. Further, it can be seen that the polyester container according to the present invention was able to easily remove the brewing agent by the treatment under high temperature and reduced pressure carried out in the mechanical recycling.

10: Polyester container 11: Mouth 12: Neck 13: Shoulder 14: Body 15: Bottom 16: Screw 17: Kabula 18: Support ring 19: Sinking 20: Ground 21: Panel 30: Polyester preform 31: Mouth 32: Body 33: Bottom 34: Screw 35: Cover 36: Support ring

Claims (6)

A polyester container with a mouth, neck, shoulders, torso, and bottom.
Contains mechanically recycled polyester and bluing agent,
The content of the bluing agent with respect to the content of the mechanically recycled polyester is 0.0001% by mass or more and 0.00125% by mass or less.
The bluing agent is a dye having a vaporization temperature of 230 ° C. or lower at 1500 Pa .
A polyester container in which the B ^* value of the mechanically recycled polyester in the L ^* a ^* b ^* color system is +3.0 or more. The polyester container according to claim 1, wherein the brewing agent is an anthraquinone-based brewing agent. The polyester container according to claim 1 or 2, wherein the content of the mechanically recycled polyester with respect to the entire polyester constituting the polyester container is 95% by mass or more. The polyester container according to any one of claims 1 to 3, wherein the body has a thickness of 0.05 mm or more and 0.54 mm or less. The polyester container according to any one of claims 1 to 4, wherein the content is a colorless and transparent liquid. A polyester preform used for producing the polyester container according to any one of claims 1 to 5.

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