JPH055028A - Gas-barrier vessel - Google Patents

Abstract

PURPOSE:To obtain the subject vessel improved in gas barrier property consisting of a copolyester having terephthaloyl group, ethylene dioxy group, 6-oxy-2-naphthoyl group and 4-oxybenzoyl group. CONSTITUTION:The objective gas-barrier vessel obtained by forming a polyester obtained by subjecting polyethylene terephthalate based polyester to acidolysis with 6-acetoxy-2-naphthoic acid and p-acetoxybenzonic acid under inert gas atmosphere at 250-300 deg.C and raising polymerization degree while gradually diminishing pressure at 270-320 deg.C and consisting of units of formula I, formula II, formula III and formula IV and containing formula I and formula II in equivalent mol number and being 15-90mol% in total amount of formula I and formula II, 10-85mol% in total amount of formula III and formula IV, being >=10mol% in a ratio of formula III to total amount of formula III and formula IV, having preferably >=0.1dl/g, further preferably >=0.3-3dl/g logarithmic viscosity (measured at 60 deg.C in pentafluorophenol).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a container made of a copolyester having improved gas barrier properties such as oxygen barrier properties.

[0002]

2. Description of the Related Art Polyester, especially polyethylene terephthalate (hereinafter sometimes abbreviated as PET),
Because it has excellent properties such as hygiene, aroma retention, and processability, it is widely used as a container for seasonings such as soy sauce and sauces, soft drinks such as juice, cola, and ramune, draft beer, cosmetics, and pharmaceuticals. It's being used. Further, in addition to the above-mentioned properties, it is lighter than glass, and has appropriate pressure resistance and gas barrier properties, and therefore, further expansion as a substitute for glass bottles is expected in the future. However, the shelf life of lager beer, wine, etc., which is expected to be the largest market as a substitute for glass bottles, will be long, and for carbonated drinks, etc., the surface area of the container per unit volume will increase due to the miniaturization of the container. There is a strong demand for improvement of the gas barrier property of the container in order to further reduce the invasion of oxygen and the dissipation of carbon dioxide from the container. The improvement of the gas barrier property of PET itself is already at a fairly high level, and it is extremely difficult to realize it because it needs to be improved without impairing the mechanical properties such as container molding performance and pressure resistance. Is.

Conventionally, various methods have been proposed for improving the gas barrier property of PET containers. For example, a method of coating polyvinylidene chloride or the like on the inner and outer layers of the container, or a saponification product of ethylene-vinyl acetate copolymer, etc.
Although a method of forming a multilayer structure of layers (Japanese Patent Laid-Open No. 56-77143) and the like have been proposed, these methods require equipment for coating or a multilayer container in addition to conventional polyester molding equipment, which is industrial. Not only is it disadvantageous in the case of using multi-layer containers due to the use of different types of polymers, but it also has the disadvantages of collecting and reusing used containers and incinerating them. There is. In addition, a method for producing a container from a blend of polyester and a different polymer such as nylon has been proposed (Japanese Patent Publication No. 53-33618 and Japanese Patent Publication No. 56-64839). In this case, it is possible to manufacture the container with the existing equipment, but it is disadvantageous in that the physical property of the container is deteriorated and the recovery and reuse are performed.

On the other hand, in recent years, a method of using a so-called thermotropic liquid crystal polymer which forms an optically anisotropic molten phase as a gas barrier material has been proposed (JP-A-61-61).
-192762, JP-A-62-119265, JP-A-62-187033, JP-A-64-4
No. 5242, JP-A-1-288421). Also, in Polym. Prepr. (Am. Chem. So
c. , Div. Polym. Chem. ), 30
(1), 3-4 (1989), oxygen at 35 ° C. of a melt-extruded film obtained from a thermotropic liquid crystal polymer produced from 40 mol% polyethylene terephthalate and 60 mol% 4-acetoxybenzoic acid. Gas permeation amount is 36ml ・ 20μm / m ↑ 2 ・ day ・ atm
It has been reported that

[0005]

However, when the conventionally proposed thermotropic liquid crystal polymer is used as a molded body for an oxygen barrier, there are always many problems. That is, the first problem is that the molded articles obtained from the thermotropic liquid crystal polymers proposed hitherto generally have high crystallinity, large anisotropy of mechanical properties, and small elongation. The point is that stretching is substantially impossible. It is very difficult to mold such polymers into various molded articles for oxygen barrier, such as films, sheets, bottles, cups, trays and bags. A second problem is that it is difficult to say that the obtained molded product has a sufficiently high oxygen barrier property. For example, the oxygen gas permeation amount of the film obtained from the thermotropic liquid crystal polymer produced from the above-mentioned polyethylene terephthalate and 4-acetoxybenzoic acid is 36 ml · 20 μm as described above.
As reported as m / m ↑ 2 · day · atm, the polymer is not necessarily a high performance oxygen barrier material.

Further, in JP-A-62-68813, a mixture of acetoxy aromatic carboxylic acid of p-acetoxybenzoic acid and 6-acetoxy-2-naphthoic acid is reacted with polyethylene terephthalate or polybutylene terephthalate. The resulting copolyester is disclosed, and it is described that the flexural strength, flexural modulus, and heat distortion temperature are improved as compared with the case where only p-acetoxybenzoic acid is used as the acetoxy aromatic carboxylic acid. .. However, this publication does not describe a container made of the copolyester, and the copolyester has an excellent gas barrier property,
There is no disclosure about whether or not it has excellent properties such as moldability (stretchability) and low temperature fluidity.

[0007]

[Means for Solving the Problems] In view of such a situation,
The present inventors have completed the present invention as a result of intensive studies to provide a polyester container having an excellent gas barrier property that cannot be achieved by conventional polyester containers.

That is, the present invention substantially includes the following chemical formula 5

[0009]

[Chemical 5]

The structural unit (1) represented by

[0011]

[Chemical 6]

The structural unit (2) represented by

[0013]

[Chemical 7]

The structural unit (3) represented by

[0015]

[Chemical 8]

Constituting the structural unit (4), the structural unit (1) and the structural unit (2) are present in substantially the same number of moles, and the total of the structural unit (1) and the structural unit (2). The amount of the structural unit (3) and the structural unit (4) is 10 to 85 mol%, and the total amount of the structural unit (3) and the structural unit (4) is (3). The present invention provides a container made of polyester having a ratio of 10) of 10 mol% or more.

The term "container" used in the present specification means a molded article (packaging material) mainly suitable for packaging foods and drinks, pharmaceuticals and the like. Such molded articles include sheets obtained by molding the polyester according to the present invention; films; bottomed containers such as bottles, trays, cups and bags.

The present invention will be described in detail below. The structural unit (1) of the polyester used in the present invention is terephthalic acid,
Alternatively, it is a terephthaloyl group as introduced by its ester-forming derivative. A part of the structural unit (1), preferably 20 mol% or less of the structural unit (1), may be replaced with a structural unit that can be introduced by another dicarboxylic acid or its ester-forming derivative.
Examples of the dicarboxylic acid component other than terephthalic acid include isophthalic acid, 2,6-naphthalenedicarboxylic acid,
2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,
Examples thereof include succinic acid, adipic acid and sebacic acid.
In addition, if the amount of the polyester obtained is within a range capable of being melt-molded, a part of the structural unit (1) may be formed by a polyvalent carboxylic acid such as trimellitic acid, trimesic acid or pyromellitic acid or an ester-forming derivative thereof. It is also possible to replace it with a structural unit that can be introduced.

The structural unit (2) in the polyester used in the present invention is an ethylenedioxy group introduced by ethylene glycol, but a part thereof, preferably 20 mol% or less of the structural unit (2) is used. , May be replaced with a structural unit that can be introduced by another glycol. As glycols other than ethylene glycol,
For example, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,
5-pentanediol, neopentyl glycol, 1,
6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, o-, m
-Or p-xylylene glycol and the like can be mentioned.
Further, when the amount of the obtained polyester is within a range capable of being melt-molded, a part of the structural unit (2) is replaced with glycerin,
It is also possible to replace it with a constitutional unit that can be introduced by a polyhydric alcohol such as trimethylolpropane, trimethylolpropane, and pentaerythritol.

The constitutional unit (1) and the constitutional unit (2) in the polyester used in the present invention are usually polyethylene terephthalate-based compounds obtained by the reaction of terephthalic acid or its ester-forming derivative with ethylene glycol as a main starting material. By using the polyester as one of the raw materials, it is introduced into the molecule of the polyester used in the present invention. The polyethylene terephthalate-based polyester can be produced by the method conventionally proposed for producing polyethylene terephthalate. For example, it can be obtained by a method in which a dicarboxylic acid and a glycol are subjected to an esterification reaction and then polycondensation, a method in which a dicarboxylic acid ester and a glycol are transesterified, and then a polycondensation. There is no particular restriction on the degree of polymerization of the polyethylene terephthalate polyester used as a raw material polyester when producing the polyester used in the present invention, but the intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol / tetrachloroethane by weight is It is desirable to use one of 0.01 to 1.5 dl / g.

The structural unit (1) and the structural unit (2) are
It is present in the polyester in a total amount of 15 to 90 mol%, preferably 25 to 85 mol%, more preferably 30 to 80 mol%.

On the other hand, the constitutional unit (3) and the constitutional unit (4) in the polyester used in the present invention are 6 respectively.
6-oxy-2-naphthoyl group as introduced by hydroxy-2-naphthoic acid or its ester-forming derivative and 4-oxybenzoyl group as introduced by p-hydroxybenzoic acid or its ester-forming derivative Is. 10 of the structural unit (3) and part of the structural unit (4), preferably a combination thereof.
The mol% or less may be replaced by a constituent unit that can be introduced by another hydroxyaromatic carboxylic acid or its ester-forming derivative. Examples of hydroxyaromatic carboxylic acids other than 6-hydroxy-2-naphthoic acid and p-hydroxybenzoic acid include m-hydroxybenzoic acid, 4-hydroxy-3-chlorobenzoic acid, and 4-hydroxy-3-chlorobenzoic acid.
Hydroxy-3,5-dimethylbenzoic acid, 4-hydroxy-3-methylbenzoic acid, 7-hydroxy-2-naphthoic acid, 4-hydroxy-1-naphthoic acid, 5-hydroxy-1-naphthoic acid and the like can be mentioned. ..

In the polyester used in the present invention, the total content of the structural unit (3) and the structural unit (4) is in the range of 10 to 85 mol% in the polyester, preferably 15 to 75 mol%. , And more preferably 20
˜70 mol%. When the total content of the structural unit (3) and the structural unit (4) exceeds 85 mol%, the moldability of the polyester produced to a container is remarkably reduced, and when the total content is less than 10 mol%, the resulting container is obtained. The gas barrier property of is greatly reduced. The ratio of the structural unit (3) to the total of the structural unit (3) and the structural unit (4) is at least 10 mol% from the viewpoint of the moldability of the polymer produced and the gas barrier property of the resulting container. is necessary.

The structural unit (3) and the structural unit (4) in the polyester used in the present invention are usually introduced into the polymer molecule by using the corresponding acyloxycarboxylic acid as a raw material. The acyloxycarboxylic acid is preferably an acetoxycarboxylic acid obtained by reacting a corresponding hydroxycarboxylic acid with acetic anhydride.

The polyester used in the present invention usually has the property of forming a liquid crystal (indicating optical anisotropy) in the molten phase. Confirmation of such optical anisotropy in the melt phase is carried out by using a polarization microscope equipped with a heating device under a crossed Nicol, and a thin slice of the sample, preferably 5 to 20 μm, is well known to those skilled in the art. It can be carried out by sandwiching a thin slice between cover glasses and observing at a constant heating rate and seeing that light is transmitted at a certain temperature or higher. In this observation, polarized light transmission can be more reliably observed by applying a light pressure to the sample sandwiched between the cover glasses at high temperature or by sliding the cover glass.
In this observation, the temperature at which polarized light starts to transmit is the transition temperature to the optically anisotropic molten phase. This transition temperature is preferably 300 ° C. or lower from the viewpoint of ease of melt molding.

The polyester used in the present invention can be produced, for example, by first acidifying a polyethylene terephthalate type polyester with 6-acyloxy-2-naphthoic acid and p-acyloxybenzoic acid to prepare a polyester fragment, and subsequently the polyester fragment. It is carried out by a method for preparing a target polyester by increasing the polymerization degree of. The first-stage acidolysis is usually carried out under an atmosphere of an inert gas such as nitrogen, argon, carbon dioxide, for example, 250 to 3
It is carried out at 00 ° C.

At the stage of the acidolysis reaction of 6-acyloxy-2-naphthoic acid and p-acyloxybenzoic acid with the raw material polyester, most of the theoretical distillate amount of lower aliphatic acid such as acetic acid goes out of the system. Next, the lower aliphatic acid is further eliminated from the product of the acidolysis reaction remaining in the system at 250 to 350 ° C. under reduced pressure, which is suitable for forming a desired article, preferably 0.1 dl / g or more. Increase degree of polymerization to logarithmic viscosity. In this case, the polymerization temperature is preferably 270 ° C. or higher from the viewpoint of reaction rate, and 350 ° C. or lower from the viewpoint of suppressing decomposition of the produced polyester, and particularly preferably 270 to 320 ° C. In this polymerization stage, the degree of vacuum was gradually increased until the final pressure was 1 m.
It is desirable that the pressure is not more than mHg, preferably not more than 0.5 mmHg. Further, as a method for further increasing the molecular weight, it is possible to use a solid-phase polymerization method or the like well known in the art.

The logarithmic viscosity of the polyester used in the present invention measured at 60 ° C. in pentafluorophenol is 0.1 dl / g or more, preferably 0.3 dl / g or more, from the viewpoint of the mechanical strength of the molded product. Preferably 0.5 dl /
It is preferably g or more. Although there is no critical upper limit to the logarithmic viscosity, it is preferably 3.0 dl / g or less from the viewpoint of ease of melt polymerization and moldability. The structural units (1), (2) of the polyester used in the present invention,
The composition ratios of (3) and (4) are determined by dissolving the polymer in an appropriate solvent and measuring the NMR spectrum of the solution, and usually have a composition substantially the same as the composition ratio of the charged raw materials. A polymer is obtained.

The container of the present invention is obtained by molding the above-mentioned predetermined polyester by a usual molding method such as injection molding, blow molding, biaxial stretch blow molding, vacuum molding, compression molding, etc. by utilizing its excellent moldability. It is manufactured by Specifically, the container of the present invention is formed into a tray by vacuum- or pressure-forming a sheet, obtained by deep-drawing an unstretched sheet, or a preform (parison) obtained by injection molding. , Those obtained by direct-blowing or biaxially-stretching blowing a parison such as a parison obtained by bottoming a pipe.

Further, the container of the present invention is not limited to the one obtained by molding the polyester substantially consisting of the above structural units (1), (2), (3) and (4) alone, and other resin. And a container made of a coating and a multilayer structure with a layer made of another resin. Examples of other resins include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, and polyamide resins such as nylon.

The container of the present invention comprises the above structural unit (1),
Due to the polyester substantially consisting of (2), (3) and (4), it has an excellent oxygen barrier property, for example, 20 to 20 of a container made of polyethylene terephthalate
It has 400 times the performance. The structural unit (1),
By subjecting a molded article obtained from the polyester substantially consisting of (2), (3) and (4) to a heat treatment, the oxygen barrier property of the molded article may be further improved, and the container of the present invention is It also includes those that have been subjected to such heat treatment. The composition of each structural unit in the polyester substantially consisting of the structural units (1), (2), (3) and (4) to be used, the conditions of heat treatment optionally applied, and the container for the laminated structure are the same as those of the polyester. 20 ° C. of the wall surface by adjusting various conditions such as the ratio of the layer to be shown in the wall thickness direction, the type of the different polymer and the blend ratio when the polyester is used in a blend with the different polymer. Oxygen permeation measured by 20 ml
It is possible to easily obtain a container having a thickness of 20 μm / m ↑ 2 · day · atm or less. Further, the polyester has extremely low humidity dependency of oxygen barrier property. Therefore, the polyester is preferably used as a material for various containers that require an oxygen barrier property. Therefore, the container of the present invention has a wide variety of uses, and for example, it can be used as a gas barrier packaging material in the fields of foods, pharmaceuticals, cosmetics, textiles, industrial chemicals and the like.

[0032]

The present invention will be specifically described with reference to the following examples. The measurement of the physical property values in this example was carried out according to the following methods.

1) Logarithmic viscosity (η ↓ inh) 0.1 g / dl using pentafluorophenol solvent
The concentration was measured at 60 ° C.

Η ↓ inh = [ln (t ↓ 1 / t ↓ 0)] / c

[Wherein η ↓ inh is logarithmic viscosity (dl / g)
, T ↓ 0 represents the flow down time (seconds) of the solvent, t ↓ 1 represents the flow down time (seconds) in the sample solution, and c represents the concentration of the sample in the solution (0.1 g / dl). .. ]

2) Thermal analysis Differential scanning calorimeter (DSC; manufactured by METTLER CORPORATION, TA-300)
Type 0) for samples that were quenched from the molten state
The melting point (Tm) and the glass transition point (Tg) were measured at a temperature rising rate of 0 ° C./min.

3) Oxygen permeability (PO ↓ 2) Gas permeability measuring device (MODERN CONTROL)
20 by using OX-TRAN10 / 50A manufactured by S company
At 0 ° C, relative humidity 0%, 65% or 100%,
The measurement was performed on a hot press film, a stretched film or a stretched film laminated with PET. The unit is ml ・ 20μm
/ M ↑ 2 · day · atm.

4) Stretchability A hot press film having a thickness of about 100 μm was prepared at a temperature of 260 to 290 ° C., and this film was 3 × 3 at a temperature of 100 to 200 ° C. using a biaxial stretching device manufactured by Shibayama Scientific Instruments Co., Ltd.
It was subjected to double biaxial stretching. Regarding the evaluation of stretchability,
A film obtained with a uniform biaxially stretched film with little thickness unevenness was evaluated as "good", and a film in which no stretchability was observed and the film was broken was evaluated as "unstretchable".

Example 1 From polyethylene terephthalate, 6-acetoxy-2-naphthoic acid and p-acetoxybenzoic acid, the total amount of the structural unit (1) and the structural unit (2) was 34 mol% by the following method. A polyester having a total amount of the structural unit (3) and the structural unit (4) of 66 mol% was obtained. That is, the intrinsic viscosity measured at 30 ° C. using a mixed solvent such as phenol / tetrachloroethane in a weight ratio is 0.65.
384 g of polyethylene terephthalate (dl.
0 mol), 1610 g of 6-acetoxy-2-naphthoic acid
(7.0 mol), and p-acetoxybenzoic acid 180
g (1.0 mol) was charged into a reactor having an internal volume of 8 l equipped with a stirrer, a distillation column and a nitrogen gas inlet, and the inside of the reaction system was replaced with nitrogen three times, followed by stirring at 280 ° C. for 1 hour under a nitrogen stream. After heating, gradually reduce the pressure in the system to about 30 m
The reaction was carried out at mHg for about 2 hours. As a result of this operation, about 90% of the theoretical amount of acetic acid was distilled. Next, the degree of vacuum in the reaction system was further increased, and the reaction was performed at 1 mmHg or less for 5 hours, and then the polymer was taken out.

By dissolving the obtained polymer in trifluoroacetic acid and measuring the .sup.1H-NMR spectrum, it was confirmed that the composition of each structural unit of the polymer was substantially the same as the raw material composition charged. As a result of observation with a polarizing microscope equipped with a heating device, the obtained polymer began to transmit light at around 150 ° C, and the amount of transmitted light further increased with increasing temperature, and finally increased to 350 ° C. Even after that, an optically anisotropic molten phase was still formed. In addition, a sample prepared by rapidly cooling the polymer from the molten state was used.
As a result of DSC analysis at a heating rate of 0 ° C./min, no endothermic peak was observed except that a glass transition point was observed at 94 ° C.

This polymer was melt hot pressed at 280 ° C. and then rapidly cooled with a water cooling type cooling press to obtain a thickness of about 10
A 0 μm film was obtained. This film was subjected to simultaneous biaxial stretching of 3 × 3 times at 160 ° C. using a biaxial stretching device manufactured by Shibayama Scientific Instruments Co., Ltd. As a result, a highly transparent and uniform film having a thickness of about 10 μm was obtained.

Logarithmic viscosity of the present polymer, DSC analysis result,
Table 2 shows the evaluation results of the oxygen permeation amount and stretchability (3 × 3 times simultaneous biaxial stretching) of the press film.

Examples 2 to 6 Polyethylene terephthalate, 6-acetoxy-2-naphthoic acid and p-acetoxybenzoic acid were used in the same manner as in Example 1, and the total amount of the structural unit (1) and the structural unit (2), A polyester was produced in which the amounts of the structural unit (3) and the structural unit (4) were each in the proportions shown in Table 1. Logarithmic viscosity of the obtained polyester, DSC analysis result, oxygen permeability of the press film and stretchability (3 × 3
Table 2 shows the evaluation results of double simultaneous biaxial stretching).

Comparative Example 1 In Example 1, p-acetoxybenzoic acid was used without using 6-acetoxy-2-naphthoic acid, and [total amount of structural unit (1) and structural unit (2)] / [structural unit] Polyester was obtained in the same manner as in Example 1 except that the molar ratio of (amount of (4)] was changed to 57/43.

Logarithmic viscosity of the present polymer, DSC analysis result,
Table 2 shows the evaluation results of the oxygen permeation amount and stretchability (3 × 3 times simultaneous biaxial stretching) of the press film.

Comparative Example 2 Table 2 shows the results of DSC analysis of the polyethylene terephthalate used as the raw material in Example 1, and the evaluation results of the oxygen permeation amount and stretchability (3 × 3 times simultaneous biaxial stretching) of the press film.

[0047]

[Table 1]

[0048]

[Table 2]

Example 7 The press film obtained in Example 6 was heat set at 150 ° C. for 15 minutes. The amount of oxygen permeated at 65% relative humidity of the film obtained after heat setting is 12.5.
It was ml · 20 μm / m ↑ 2 · day · atm.

Examples 8 to 10 and Comparative Examples 3 to 4 The press films obtained in Examples 1, 2 and 4 and Comparative Examples 1 and 2 were used, respectively, at a temperature of 100 to 200 ° C.
15 times at a temperature of 120 to 200 ° C. for a film obtained by simultaneously biaxially stretching 3 times and obtaining a better stretched film.
A heat setting process for 1 minute was performed. Table 3 shows the amount of oxygen permeated at a relative humidity of 65% of the film obtained after the heat setting treatment.

[0051]

[Table 3]

Example 11, Comparative Examples 5 to 6 Using the thermal liquid crystalline polyester of Example 1 and a PET resin having an intrinsic viscosity of 0.75 dl / g measured at 30 ° C. in a mixed solvent of phenol / tetrachloroethane and the like by weight. A multilayer sheet was formed. That is, the thermal liquid crystal polymer and the PET resin were vacuum-dried at 80 ° C. and 150 ° C. for 24 hours, and then coextruded with two extruders to obtain a three-layer sheet of PET / thermal liquid crystal polymer / PET. The thickness of each layer of PET / thermo-liquid crystal polymer / PET of the obtained sheet was 280 μm / 20 μm / 200 μm. Using the biaxial stretching device used in Example 1
A laminated stretched film was obtained by simultaneously biaxially stretching at 3 to 3 times at 0 to 120 ° C. (Example 11).

A single layer sheet having a thickness of about 500 μm was obtained by using only the PET resin and using only one of the above extruders. This sheet was prepared by using the above biaxial stretching device 1
Simultaneous biaxial stretching was performed at 20 ° C. to 3 × 3 times to prepare a stretched film (Comparative Example 5).

The oxygen barrier performance of these stretched films was evaluated by the above method at a relative humidity of 65%. The results are shown in Table 4.

An attempt was made to form a similar PET / thermo-liquid crystal polymer / PET two-layer / three-layer film using the thermo-liquid crystal polymer of Comparative Example 1, but the intermediate layer (thermo-liquid crystal polymer layer) could not be stretched. However, a good laminated stretched film could not be obtained (Comparative Example 6).

[0056]

[Table 4]

[0057]

INDUSTRIAL APPLICABILITY The container of the present invention has an excellent gas barrier property and is useful as various packaging materials that require a high gas barrier property.

Claims (1)

What is claimed is: (Claim 1) Substantially the following chemical formula 1 The structural unit (1) represented by the following chemical formula 2 The structural unit (2) represented by the following chemical formula 3 The structural unit (3) represented by and the following chemical formula 4 The structural unit (4) is represented by the formula (1), the structural unit (1) and the structural unit (2) are present in substantially the same number of moles, and the total amount of the structural unit (1) and the structural unit (2) is 15 ~ 90
Mol%, the total amount of the structural unit (3) and the structural unit (4) is 10 to 85 mol%, and the ratio of the structural unit (3) to the total amount of the structural unit (3) and the structural unit (4) is 1
A container made of polyester of 0 mol% or more.