JP2610672B2 - Polyester composition and film, preform and container comprising the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyester composition and a film, a preform, and a container comprising the same, and more particularly, to a polyester composition excellent in gas barrier properties, surface properties, transparency and the like. It relates to a film, a preform and a container comprising the polyester composition.

Technical Background of the Invention and Problems Thereof Conventionally, glass has been widely used as a material for containers such as seasonings, oils, beer, alcoholic beverages such as sake, soft drinks such as carbonated beverages, cosmetics, and detergents. Although the glass container is excellent in gas barrier properties, the production cost is high, so that a method of collecting an empty container after normal use and circulating and reusing it has been adopted. However, since the glass container is heavy, there is a problem that the transportation cost is high, and the glass container is easily broken, which is inconvenient to handle.

In order to solve such problems, various plastic containers are used instead of glass containers. Various plastics are employed as the material according to the type of storage item and the purpose of use. Of these plastics, polyethylene terephthalate (PE)
T) has excellent heat resistance, impact resistance, gas barrier properties, and transparency, and is therefore used as a material for containers of seasonings, soft drinks, detergents, cosmetics, and the like. However, in the case of beer and carbonated beverage containers requiring the strictest gas barrier properties among these, it is hard to say that polyethylene terephthalate is still sufficient, and in order to use polyethylene terephthalate in these containers, meat is required. The gas barrier properties had to be improved by increasing the thickness.

At present, the demand for polyester containers is increasing, and in order to further expand these uses, the appearance of polyester having excellent gas barrier properties and excellent melt moldability is strongly desired.

Based on such a demand, for example, Japanese Patent Laid-Open No. 59-6462
Patent Document 4 discloses a polyalkylene isophthalate such as polyethylene isophthalate and a copolymer thereof, and a molded article formed therefrom as a packaging material having good gas barrier properties against oxygen and carbon dioxide gas. JP-A-59-67049 discloses a multilayer packaging material comprising a layer comprising a polyalkylene isophthalate or a copolymer thereof as described above, and a layer comprising a polyalkylene terephthalate such as polyethylene terephthalate or a copolymer thereof, and a multilayer packaging material comprising the same. A molded article such as a bottle is disclosed.

Further, a method of blending polyethylene isophthalate and polyethylene terephthalate (Japanese Patent Laid-Open No. 59-6465)
No. 8) has been proposed.

However, in any case, polyethylene isophthalate contains oligomers having a high melting point, and these oligomers have a problem of adversely affecting the physical properties of the obtained molded article. Similarly, in order to improve the gas barrier properties of PET, isophthalic acid is used as a dicarboxylic acid component and 1,3-bis (2-hydroxyethoxy) is used together with ethylene glycol as a dihydroxy compound component.
A copolyester obtained by copolymerizing these with benzene (JP-A-58-167617) has been proposed.

By the way, when molding a container or the like from a polyester resin, if the polyester resin contains moisture, a hydrolysis reaction occurs, and mechanical properties are reduced. Therefore, it is necessary to dry the polyester resin before molding. . However, isophthalate-based copolyesters as described in the above publication produced using a large amount of isophthalic acid as a dicarboxylic acid component have poorer crystallinity than terephthalate-based copolyesters, and have a glass transition temperature (Tg). Therefore, drying can be performed only at a low temperature, and there is a problem that drying requires a long time. Further, when the above-mentioned isophthalate-based copolyester is dried at a temperature higher than the glass transition temperature, there is a problem that the isophthalate-based copolyesters are fused together.

In general, drying of polyethylene terephthalate is usually performed at a temperature of 110 to 160 ° C., and polyethylene terephthalate sent at this temperature and an isophthalate-based copolyester dried at a lower temperature than the above temperature are used. If dry blending is performed immediately after drying, the resin temperature of polyethylene terephthalate is high, so that the resin temperature of the above isophthalate-based copolyester becomes higher than the glass transition temperature (Tg). There has been a problem that handling is difficult, for example, the copolyester pellets are broken or are fused together.

Therefore, the appearance of an isophthalate-based copolyester having a high glass transition temperature (Tg), excellent heat resistance, and containing a large amount of isophthalic acid as a dicarboxylic acid component has been desired.

As such an isophthalate-based copolyester having a high glass transition temperature (Tg), an isophthalate-based copolyester obtained by copolymerizing bis (4-β-hydroxyethoxyphenyl) sulfone is disclosed in JP-A-58-167617. Proposed.

However, the above-mentioned isophthalate-based copolyester slightly increases the glass transition temperature (Tg) but does not sufficiently increase the glass transition temperature (Tg). Further, when such a polyester is blended, the gas barrier property of the polyester composition is reduced, or When the composition is colored or the monomer component is released, there is a problem that it is not preferable from the viewpoint of food hygiene.

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and can be dried at high speed, and has heat resistance, impact resistance, surface characteristics, transparency, and gas barrier. It is an object of the present invention to provide a polyester composition which has excellent properties and does not contain a high melting point oligomer or the like.

Another object of the present invention is to provide a film, a preform, and a container comprising the above polyester composition.

The polyester composition according to the present invention comprises 50 to 95% by weight of a polyethylene terephthalate (A) and 50 to 5% by weight of a copolyester (B). 95 to 60 mol% of the acid component units are isophthalic acid component units,
4040 mol% are 2,6-naphthalenedicarboxylic acid component units, and 95-70 mol% of dihydroxy component units are ethylene glycol component units, and 5-30 mol% are 1,3
-Bis (2-hydroxyethoxy) benzene component unit, and the intrinsic viscosity [η] of the copolyester (B) measured in o-chlorophenol at 25 ° C. is 0.3 to 1.5 dl / g.
It is characterized by being.

Further, the polyester film, the polyester preform and the polyester container according to the present invention are characterized by comprising the above-mentioned polyester composition.

The polyester composition according to the present invention comprises polyethylene terephthalate and a copolyester as described above, and contains an isophthalic acid component unit and a 2,6-naphthalenedicarboxylic acid component unit as dicarboxylic acid component units constituting the copolyester. In addition, since it contains an ethylene glycol component unit and a 1,3-bis (2-hydroxyethoxy) benzene component unit as dihydroxy compound components, it can be dried at high speed, and has heat resistance, impact resistance, It has excellent transparency and gas barrier properties, and also has excellent surface properties because it does not contain a high melting point oligomer or the like.

Further, since the polyester film, polyester preform and polyester container according to the present invention are formed from the polyester composition as described above, they are excellent in heat resistance, impact resistance, transparency, gas barrier properties and high melting point oligomer. Since it does not contain any other components, it has excellent surface properties.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the polyester composition, polyester film, polyester preform, and polyester container according to the present invention will be specifically described.

The polyester composition according to the present invention comprises polyethylene terephthalate (A) and copolyester (B).

The polyethylene terephthalate (A) used in the polyester composition of the present invention is a thermoplastic polyester resin having crystallinity, and is composed of the following dicarboxylic acid component units and dihydroxy compound component units.

In the present invention, polyethylene terephthalate (A)
Is usually 80 mol% or more, preferably 90 mol% or more of terephthalic acid component units, and the dihydroxy compound component unit is usually 80 mol% or more.
As described above, preferably 90 mol% is an ethylene glycol component unit.

In addition, as the dicarboxylic acid component unit other than the terephthalic acid component unit, specifically, isophthalic acid, diphenyl ether-4,4-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, etc. Aromatic dicarboxylic acids; aliphatic carboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid and undecadicarboxylic acid; and component units derived from aliphatic dicarboxylic acids such as hexahydroterephthalic acid.

Specific examples of the dihydroxy compound component unit other than the ethylene glycol component unit include aliphatic dihydroxy compounds such as propylene glycol, 1,4-butanediol and neopentyl glycol; and aliphatic dihydroxy compounds such as cyclohexanediol and cyclohexanedimethanol. 1,3-bis- (2-hydroxyethoxy) benzene, 1,4-bis (2-hydroxyethoxy) benzene, 2,2-bis (4-β-hydroxyethoxyphenyl) propane, bis (4-β (Hydroxyethoxyphenyl) sulfone, a component unit derived from an aromatic dihydroxy compound such as bisphenol A, and the like.

As long as the terephthalic acid component unit and the ethylene glycol component unit are in the above ranges, the polyethylene terephthalate (A) may contain the dicarboxylic acid component unit and the dihydroxy compound component unit in addition to the terephthalic acid component unit and the ethylene glycol component unit. And may be contained. Further, in the present invention, polyethylene terephthalate (A) may be used as a mixture with another polyester.

The molecular weight of the polyethylene terephthalate (A) used in the present invention is not particularly limited as long as it is within a range in which various molded articles such as containers can be produced from the obtained polyester composition. However, in the present invention, the intrinsic viscosity [η] of polyethylene terephthalate (A) measured in o-chlorophenol at 25 ° C. (hereinafter sometimes referred to as IV) is usually
It is desirably 0.6 dl / g or more, preferably 0.8 dl / g or more.

The copolyester (B) contained in the polyester composition according to the present invention is composed of the following dicarboxylic acid component units and dihydroxy compound component units,
It is obtained by a co-condensation reaction of the corresponding dicarboxylic acid component and dihydroxy compound component.

In the present invention, the dicarboxylic acid component unit constituting the copolyester (B) is 95 to 60 mol%, preferably 90 to 70 mol%, is an isophthalic acid component unit, and 5 to 40 mol%, preferably
10 to 30 mol% is 2,6-naphthalenedicarboxylic acid component unit.

95 isophthalic acid units constituting the copolyester
If the amount exceeds mol%, the copolyester (B) is not preferred because the glass transition temperature (Tg) does not increase so much, whereas if the amount is less than 60 mol%, the copolyester (B)
The glass transition temperature (Tg) is undesirably high because the copolyester (B) and the polyethylene terephthalate (A) cannot be sufficiently stretched when blended and stretched.

In the present invention, since the copolyester (B) contains a 2,6-naphthalenedicarboxylic acid component unit derived from a rigid comonomer component as a constituent component unit, the copolyester (B) has a glass transition temperature ( Tg) is high, the gas barrier property is at a high level, and the content of high-melting oligomer is low. Therefore, when producing the polyester composition of the present invention comprising such a copolyester (B) and polyethylene terephthalate (A), drying can be performed at a high speed.

In the present invention, in addition to the above-mentioned isophthalic acid component unit and 2,6-naphthalenedicarboxylic acid component unit as the dicarboxylic acid component unit, other dicarboxylic acid component units in a range that does not impair the characteristics of the obtained polyester composition. It may be contained. Examples of such other dicarboxylic acid component units include component units derived from the aforementioned compounds in addition to terephthalic acid component units.

In the present invention, an ethylene glycol component unit and a 1,3-bis (2-hydroxyethoxy) benzene component unit are contained as a dihydroxy compound component unit constituting the copolyester (B). 95 to 70 mol%, preferably 90 to 80 mol%, of the dihydroxy compound component units are ethylene glycol component units, and 5 to 30 mol%, preferably 10 to
20 mol% is 1,3-bis (2-hydroxyethoxy) benzene component unit. As a dihydroxy compound component unit, an ethylene glycol component unit and 1,3-bis (2
When the (hydroxyethoxy) benzene component unit is contained in the above range, the copolyester (B) does not contain a high-melting oligomer and has a high glass transition temperature (Tg).

In the present invention, the dihydroxy compound component unit constituting the copolyester (B) includes, in addition to the ethylene glycol component unit and the 1,3-bis (2-hydroxyethoxy) benzene component unit described above, a polyester composition obtained. Other dihydroxy compound component units may be contained as long as the properties of the product are not impaired. Examples of such a dihydroxy compound component unit include the compound component units described above as the dihydroxy compound component unit, and among these, a dihydroxy compound component unit having 3 to 15 carbon atoms is preferable.

The above-mentioned copolyester (B) has an intrinsic viscosity [η] of 0.3 to 1.5 dl / g measured in o-chlorophenol at 25 ° C.
Preferably it is 0.6 to 1.0 dl / g. This intrinsic viscosity [η]
If it is less than 0.3 dl / g, it is not preferable because the mechanical strength is deteriorated. On the other hand, if it is more than 1.5 dl / g, the melt moldability is deteriorated.

The copolyester (B) used in the present invention has a glass transition temperature (Tg) of usually 68 to 95 ° C, preferably 70 to 80 ° C.
C. is desirable.

As described above, the copolyester (B) used in the present invention has a glass transition temperature (Tg) of about 60 to 70 ° C., which is higher than that of a polyester composed of an isophthalic acid component unit and an ethylene glycol component unit. Due to the high temperature, drying can be performed more quickly. Moreover,
Even if the polyethylene terephthalate (A) and the copolyester (B) are mixed immediately after drying, the copolyesters (B) rarely fuse together.

The copolyester (B) can be produced according to a conventionally known polycondensation method employed in the production of polyethylene terephthalate. In producing such a copolyester (B), the dicarboxylic acid component can be supplied to the reaction system as a dicarboxylic acid, can be supplied as a dialkyl ester thereof, and the bis β- It can also be supplied as an ester of a diol such as hydroxyethyl ester.

The hydroxy compound component can be supplied to the reaction system in the form of a dihydroxy compound, or can be supplied to the reaction system in the form of a dihydroxy ester of a carboxylic acid.

As the catalyst at the time of the copolycondensation, a conventionally known catalyst used in the production of polyethylene terephthalate (A) can be used. As these catalysts, metals such as antimony, germanium and titanium or compounds thereof can be used. As the form of the compound, oxides, hydroxides, halides, inorganic acid salts, organic acid salts, complex salts, double salts, alcoholates, phenolates and the like are used. These catalysts can be used alone or as a mixture of two or more. These catalysts can be supplied to the reaction system from the initial stage of the esterification reaction or transesterification reaction, or can be supplied to the reaction system before proceeding to the polycondensation reaction stage.

Further, at the time of copolycondensation, a catalyst for the transesterification reaction used in the production of polyethylene terephthalate (A),
Various additives such as a diethylene glycol production inhibitor, a heat stabilizer, a light stabilizer, a lubricant, a pigment, and a dye can be used.

As a catalyst for these transesterification reactions, metal compounds such as calcium, magnesium, lithium, zinc, cobalt, and manganese can be used. These compounds may be in the form of oxides, hydroxides, halides,
Inorganic acid salts and organic acid salts are used. Examples of the diethylene glycol formation inhibitor include amines such as triethylamine and tri-n-butylamine, and quaternary ammonium compounds such as tetraethylammonium hydroxide and tetrabutylammonium hydroxide. As a stabilizer such as a heat stabilizer, a phosphorus compound such as phosphoric acid, phosphorous acid, hypophosphorous acid, or an ester thereof can be used.

In the present invention, the copolyester (B) is produced by a conventionally known melt polycondensation method, and in some cases, by employing a solid phase polycondensation method after the melt polycondensation method.

In the above-described melt polycondensation method, a so-called direct polycondensation method can be employed, and a so-called transesterification polycondensation method can also be employed. That is,
The melt polycondensation method will be described in more detail. For example, isophthalic acid and 2,6-naphthalenedicarboxylic acid or a dicarboxylic acid containing these as main components or ester derivatives thereof, ethylene glycol or ethylene glycol and 1,3-bis (2-hydroxyethoxy) benzene or a condensate thereof with a dicarboxylic acid, and optionally a polyfunctional compound containing three or more carboxyl groups or hydroxyl groups simultaneously or sequentially, preferably at a temperature of 100 to 280 ° C. To form these initial polycondensates by esterification or transesterification, and then to polycondensate them at a temperature above their melting point, preferably at 200 to 300 ° C, while stirring under vacuum or under an inert gas flow. Can be exemplified.

In the present invention, the copolyester (B) can also be produced by extending the molecular weight by further solid-phase polycondensation of the polyester obtained by the above-mentioned melt polycondensation method. Specific description of such a solid-phase polycondensation method includes, for example, pulverizing a polyester by a melt polycondensation method, and subjecting it to a temperature lower than the melting point, preferably at 180 to 240 ° C. under vacuum or flowing an inert gas. A method of holding underneath can be adopted.

Various known methods can be used to obtain the polyester composition of the present invention from the above polyethylene terephthalate (A) and copolyester (B). For example, a Henschel mixer, a v-blender, a ribbon blender, a tumbler The method of mixing a polyethylene terephthalate (A) and a copolyester (B) using a blender etc. can be mentioned. Since the glass transition temperature of the copolyester (B) is high, even if the polyethylene terephthalate (A) and the copolyester (B) are mixed immediately after drying, the copolyesters (B) are fused together. It is unlikely to be lost. Therefore, the polyethylene terephthalate (A) and the copolyester (B) can be rapidly mixed after drying both. Moreover,
After mixing in this manner, a method of melt-kneading with a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or the like, followed by granulation or pulverization can be given.

In the thus obtained polyester composition according to the present invention, polyethylene terephthalate (A) is used in an amount of 50 to 95% by weight, preferably 70 to 90% by weight, based on the total weight of the polyester composition. Polyester (B) is 50
-5% by weight, preferably 30-10% by weight.

When the amount of the polyethylene terephthalate (A) is less than 50% by weight, the characteristics of the polyethylene terephthalate (A) are not sufficiently exhibited, and thus it is not preferable.
When the amount exceeds the above range, the properties of the copolyester (B) are not sufficiently exhibited, so that it is not preferable.

The glass transition temperature (Tg) of the polyester composition thus obtained is usually 75 to 85 ° C, preferably 80 to 85 ° C.
C. is desirable.

As described above, the polyester composition according to the present invention has a higher glass transition temperature (Tg) as compared with a polyester composition containing a conventional isophthalate-based copolyester, so that the composition can be used at a high temperature, and thus at a high speed. Can also be dried.

The polyester resin composition according to the present invention includes heat stabilizers, weather stabilizers, antistatic agents, lubricants, mold release agents, pigment dispersants, pigments or dyes, and various compounding agents usually used by adding to polyester. Can be added in a range that does not impair the object of the present invention.

The polyester resin composition according to the present invention, as it is,
Alternatively, it can be used in various shapes such as sheet, plate, tube, hollow, and container.

The polyester film according to the present invention is produced from the above polyester composition by an ordinary molding method.
This polyester film may be an unstretched product or a stretched product.

In the case of an unstretched product, it is desirable that the thickness of the polyester film is usually 50 to 900 μm, preferably 200 to 600 μm.

In the case of a stretched product, there are a uniaxially stretched film and a biaxially stretched film. In a uniaxially stretched film, the stretching ratio is usually in the range of 1.1 to 10 times, preferably 1.2 to 8 times, and particularly preferably 1.5 to 7 times.

In the biaxially stretched film, the stretching ratio is usually 1.1 to 8 times, preferably 1.2 to 7 times, particularly preferably 1.5 to 6 times in the vertical direction, and usually 1.1 to 8 times in the horizontal direction.
It is desirable that the ratio be in the range of 1.2 times, preferably 1.2 times to 7 times, particularly preferably 1.5 times to 6 times.

To produce the polyester film according to the present invention,
Any conventionally known method can be adopted.
In general, a film-like material formed from the polyester composition or a polyester composition further containing the additive, if necessary, as it is, or once cooled and solidified to a temperature below the glass transition point and then reheated Then, the original molded product is a glass transition point or melting point, preferably about 80 ℃ above the glass transition point or glass transition point
Stretching may be performed in a high temperature range. In order to heat-set the stretched film, an appropriate short-time heat treatment may be performed at the stretching temperature or higher.

In order to produce the stretched polyester film according to the present invention, in the case of an original molded film-like material, a method of uniaxially stretching an unstretched film-like material (uniaxial stretching), after stretching in the longitudinal axis direction Further, a method of stretching in the horizontal axis direction (biaxial stretching), a method of simultaneously stretching in the vertical axis direction and the horizontal axis direction (biaxial stretching), a method of successively stretching in any one direction after biaxial stretching, Specific examples thereof include a method of stretching in both directions after biaxial stretching, and a so-called vacuum forming method of stretching by stretching the space between the film and the mold under reduced pressure.

The polyester composition of the present invention can be processed into a sheet according to the production of the polyester film.

The polyester preform according to the present invention is manufactured using the above-mentioned polyester composition.

For example, the polyester preform of the present invention can be obtained by injection-molding the polyester composition.

The polyester container according to the present invention can be manufactured, for example, by press-molding a sheet made of the polyester composition, or by, for example, stretch blow-molding the polyester preform.

As the stretch blow molding method, the above preform is stretched in the longitudinal direction within the range of the stretching temperature in the composition, and then further blow molded to stretch in the horizontal axis direction (biaxial stretch blow molding). Method).

For example, in order to produce the polyester container of the present invention by a biaxial stretch blow molding method, one end of a bottomed parison molded by a usual injection molding machine or one end of a parison molded by an extrusion molding machine is bottomed. The obtained parison is 80 to 120 which is the stretching temperature of the polyester composition.
° C., preferably 90 to 110 ° C., in the longitudinal direction by blowing a rod and pressurized gas moving in the longitudinal direction in the blow mold.
1.5 to 3.5 times, preferably 2 to 3 times and 2 to 3 in the horizontal axis direction
A method of stretching by a factor of 5, preferably by a factor of 3 to 4.5 can be exemplified. Also, as a molding method by injection molding,
Either a two-stage system using a cold parison or a one-stage system using a hot parison may be used.

In the present invention, in order to improve the rigidity of the polyester container, a polyethylene terephthalate (A) layer may be laminated on the inner layer and the outer layer of the polyester composition layer.

The polyester container according to the present invention has excellent transparency and gas barrier properties, and can be used for various applications. In particular, biaxially stretch blow-molded containers have excellent gas barrier properties and good transparency, so that they can be used as containers for seasonings, oils, alcoholic beverages, cosmetics, detergents, etc. It is suitable for containers for sparkling beverages, such as cider, beer and the like. That is,
By using the polyester container according to the present invention, the shelf life can be extended without increasing the thickness of the container as in a conventional container, and the obtained container has excellent transparency.

Effect of the Invention The polyester composition according to the present invention comprises polyethylene terephthalate (A) and copolyester (B) as described above, and isophthalic acid component units and 2,6 as dicarboxylic acid component units constituting the copolyester. −
Since it contains naphthalenedicarboxylic acid component units and ethylene glycol component units or ethylene glycol component units and 1,3-bis (2-hydroxyethoxy) benzene component units as dihydroxy compound component units, high speed It can be dried, has excellent heat resistance, impact resistance, transparency, and gas barrier properties, and has excellent surface characteristics because it does not contain a high melting point oligomer or the like.

Further, since the polyester film, polyester preform and polyester container according to the present invention are formed from the polyester composition as described above, they are excellent in heat resistance, impact resistance, transparency, gas barrier properties and high melting point oligomer. Since it does not contain any other components, it has excellent surface properties.

[Examples] Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Reference Example 1 A copolyester was polymerized as follows.

The following components were added to one stainless steel reactor equipped with a stirrer, a nitrogen gas inlet, and a condenser.

122.5 g isophthalic acid 17.7 g naphthalenedicarboxylic acid 94.8 g ethylene glycol 24.4 g 1,3-bis (2-hydroxyethoxy) benzene 0.33 g 1,1,1, -trishydroxymethylpropane 0.058 g titanylacetyl 0.077 g of acetonate Sb ₂ O ₃ 0.010 g of tetrasodium ethylenediaminetetraacetate 0.027 g of manganese hypophosphite monohydrate The reaction mixture was placed under a nitrogen atmosphere at 220 ° C. for 1 hour and at 240 ° C. for 25 minutes. Heated. During this time, water was continuously distilled off. Then 0.164 g of tris (nonylphenyl) was added to the mixture in the reactor with phosphite. Reaction temperature 25
Raised to 0 ° C. and kept under nitrogen atmosphere for 35 minutes. The nitrogen gas flow was then stopped and a vacuum of less than 0.4 mmHg was applied. The reaction was continued at 275 ° C. for less than 0.4 mmHg for 4 hours. The resulting copolyester had an intrinsic viscosity of 0.83 dl / g. The glass transition temperature was as high as 73 ° C., the transmittance of carbon dioxide was 3.0 cc · mm / m ² · day · atm, and the gas barrier properties were good.

Reference Examples 2 to 7 In the same manner as in Reference Example 1, a copolyester having a composition shown in Table 1 was synthesized, a sheet was formed from this copolyester, and gas barrier properties were measured.

 Table 1 shows the results.

Examples 1 to 6, Comparative Examples 1 to 8 100 parts of polyethylene terephthalate (manufactured by Mitsui Pet Resin Co., Ltd., Mitsui PET J135) dried at 150 ° C. for 10 hours are shown in Table 2 of the copolyester of Reference Example 1. The mixture was melt-extruded at a molding temperature of about 250 to 290 ° C. using an extruder.After cooling, the mixture was cut using a cutter and pellets of a composition of polyethylene terephthalate and copolyester were obtained. Was prepared. Further, press molding was performed using the pellets to produce a press sheet having a thickness of about 600 μm. Next, a press sheet of these compositions was simultaneously stretched three times in the longitudinal and transverse directions using a biaxial stretching apparatus, to produce a biaxially stretched film.

Each of the obtained biaxially stretched films had a thickness of about 50 μm, was uniform in thickness, and was uniformly stretched. The press sheet, biaxially stretched film, transparency and carbon dioxide permeability coefficient of the obtained composition were as shown in Table 2.

Compared to the case where the compounds of Reference Examples 1, 2, and 3 were mixed with PET, when those of Reference Examples 4 and 6 were mixed, the Tg decreased, and
In the case of using 5,7, the effect of improving the carbon dioxide gas permeability coefficient was small.

Examples 7 to 9 and Comparative Examples 9 to 11 The mixtures of polyethylene terephthalate and copolyester in Examples 1 to 3 were each injection-molded at a molding temperature of about 270 ° C. using an injection molding machine, and each had a thickness of about
A 3.2 mm preform (cold barison) was prepared. Next, each of these preforms was biaxially stretched and blow-molded to about 2.5 times in length and about 4 times in width using a biaxially stretched blow molding machine to produce a stretched bottle having an internal volume of about 1. The results of measuring the transparency and carbon dioxide permeability of the side surfaces of these stretched bottles are as shown in Table 3.

Claims (4)

(57) [Claims] 1. A dicarboxylic acid component unit comprising 50 to 95% by weight of a polyethylene terephthalate (A) and 50 to 5% by weight of a copolyester (B) as described below. 95 to 60 mol% of the isophthalic acid component unit,
40 mole% is 2,6-naphthalenedicarboxylic acid component units, and 95-70 mole% of dihydroxy compound component units
Is an ethylene glycol component unit, and 5 to 30 mol%
1,3-bis (2-hydroxyethoxy) benzene component unit, and the intrinsic viscosity [η] of the copolyester (B) measured in o-chlorophenol at 25 ° C. is 0.3 to 1.5.
A polyester composition having a dl / g ratio. 2. A dicarboxylic acid component unit comprising 50 to 95% by weight of a polyethylene terephthalate (A) and 50 to 5% by weight of a copolyester (B) as shown below. Is from 95 to 60 mol% of isophthalic acid component units, from 5 to 40 mol% of 2,6-naphthalenedicarboxylic acid component units, and from 95 to 70 mol% of dihydroxy compound component units are by ethylene glycol component units. 5 to 30 mol% are 1,3-bis (2-hydroxyethoxy) benzene component units, and the intrinsic viscosity [η] of the copolyester (B) measured in o-chlorophenol at 25 ° C. is 0.3.
A film comprising a polyester composition having a weight of about 1.5 dl / g. 3. A dicarboxylic acid component unit comprising 50 to 95% by weight of polyethylene terephthalate (A) and 50 to 5% by weight of a copolyester (B) as described below. 95 to 60 mol% of the isophthalic acid component unit,
40 mole% is 2,6-naphthalenedicarboxylic acid component units, and 95-70 mole% of dihydroxy compound component units
Is an ethylene glycol component unit, and 5 to 30 mol%
1,3-bis (2-hydroxyethoxy) benzene component unit, and the intrinsic viscosity [η] of the copolyester (B) measured in o-chlorophenol at 25 ° C. is 0.3 to 1.5.
A preform comprising a dl / g polyester composition. 4. A dicarboxylic acid component unit comprising 50 to 95% by weight of a polyethylene terephthalate (A) and 50 to 5% by weight of a copolyester (B) as shown below. 95 to 60 mol% of the isophthalic acid component unit,
40 mole% is 2,6-naphthalenedicarboxylic acid component units, and 95-70 mole% of dihydroxy compound component units
Is an ethylene glycol component unit, and 5 to 30 mol%
1,3-bis (2-hydroxyethoxy) benzene component unit, and the intrinsic viscosity [η] of the copolyester (B) measured in o-chlorophenol at 25 ° C. is 0.3 to 1.5.
A container comprising a dl / g polyester composition.