JP2000017160A - Polyester resin composition and blow-molded vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester resin composition capable of providing a blow- molded vessel excellent in gas-barrier properties, heat resistance, pressure resistance and transparency when molding the blow-molded vessel, and further to provide the blow molded vessel by using the composition. SOLUTION: The polyester resin composition comprises (A) a polyethylene phthalate composed of a repeating unit derived from a dicarboxylic acid component comprising terephthalic acid and/or its ester-formable derivative, and a glycol component comprising ethylene glycol and/or its ester-formable derivative, and (B) a syndiotactic polypropylene in an amount of 0.01-1,000 ppm, and the blow-molded vessel is formed out of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition and a hollow molded container comprising the same, and more particularly, the present invention is suitable for filling liquids such as beverages.
A polyester resin composition capable of molding a hollow molded container having gas barrier properties, transparency, heat resistance and pressure resistance with good productivity, a preform formed from the polyester resin composition, and a preform obtained by stretching the preform The present invention relates to a hollow molded container.

[0002]

BACKGROUND OF THE INVENTION In recent years, various plastic materials have been used as materials for containers for filling liquids such as carbonated beverages, juices, natural water, sake, various drinking teas, edible oils, and liquid seasonings. Above all, polyesters such as polyethylene terephthalate (PET) are widely used as materials for forming hollow molded containers for beverages because of their excellent transparency during molding, gas barrier properties, heat resistance and mechanical strength.

[0003] In such a hollow molded container, a considerable period of time usually elapses after various beverages are filled and consumed by a consumer. For this reason, in the case of a hollow molded container having insufficient gas barrier properties, there has been a problem that the contents are deteriorated due to permeation of oxygen from the outside and dissipation of carbon dioxide from the inside.

[0004] In addition, for hollow molded containers for various beverages, etc.,
In many cases, beverages and the like that have been heat-sterilized are filled at a high temperature. At this time, the hollow molded container has sufficient heat resistance so that the high-temperature filling does not cause problems such as clouding, shrinkage, expansion, etc. of the hollow molded container, and problems such as loss of independence due to the deformation. Is required.

[0005] Furthermore, when a beverage or the like is filled at a high temperature and sealed, the inside of the hollow molded container tends to be pressurized, and when cooled, the inside of the hollow molded container tends to be decompressed. Even in the case of such a pressure change, the hollow molded container has sufficient pressure resistance so that the hollow molded container does not cause deformation such as contraction and expansion or damage to the independence due to the deformation. Required.

[0006] In addition to these properties, plastics forming hollow molded containers for liquid beverages are strongly required to have transparency. Furthermore, when manufacturing a hollow molded container, a material that can be manufactured with high productivity is required, and it is desired to manufacture at a high speed. In order to manufacture a hollow molded container at a high speed, it is preferable to use a material having a high heating crystallization rate as long as molding can be performed smoothly, and a polyester resin having a high crystallization rate is required.

However, if the crystallization rate is too high,
Since the preferable width of the molding conditions is narrowed, the yield at the time of manufacturing the molded body is reduced. Therefore, it is desirable that the material for manufacturing a hollow molded body as described above has an appropriate crystallization rate in consideration of molding efficiency and molding conditions. To meet such demands, various compounding agents have been added to polyester to adjust the physical properties of the molded article.

For example, JP-A-8-302168 proposes a polyester resin composition in which polyethylene terephthalate contains a polyolefin such as polypropylene in an amount of 0.002 to 200 ppm. Describes that the half-crystallization time is shorter than that of a material containing no polyolefin.

Japanese Patent Application Laid-Open No. 9-194697 discloses that a polyester resin has a polypropylene content of 0.1 ppb or less.
A polyester resin composition containing 1000 ppm has been proposed. 0.1ppb of polypropylene to be compounded
In the following cases, the crystallization promoting effect is insufficient,
If it exceeds 0 ppm, the crystallization promoting effect is too large,
It is described that the molding obtained therefrom becomes cloudy and the transparency is impaired.

[0010]

An object of the present invention is to provide a polyester resin composition capable of producing a hollow molded container having excellent gas barrier properties, heat resistance, pressure resistance and transparency at the time of molding a hollow molded container with high productivity, and the use of the same. In particular, an object of the present invention is to provide a polyester resin composition capable of obtaining a highly transparent hollow molded container, and a hollow molded container using the same.

[0011]

SUMMARY OF THE INVENTION The polyester resin composition of the present invention comprises:
(A) polyethylene phthalate comprising a repeating unit derived from terephthalic acid and / or a dicarboxylic acid containing an ester-forming derivative thereof, ethylene glycol and / or a diol containing an ester-forming derivative thereof, and (B) a syndiotactic polypropylene Wherein the syndiotactic polypropylene (B) is contained in the composition in an amount of 0.01 to 1000 ppm.

Further, a preform can be formed using the polyester resin of the present invention, and the preform can be further stretched to produce a hollow molded container having excellent gas barrier properties, heat resistance, pressure resistance and transparency. It is possible to obtain a well-formed, particularly highly transparent hollow molded container.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the polyester resin composition of the present invention and a hollow molded container comprising the same will be described in detail. <Polyester resin composition> The polyester resin composition of the present invention comprises (A) polyethylene terephthalate,
(B) It consists of polypropylene.

First, each of these components will be described. (A) Polyethylene terephthalate (A) Polyethylene terephthalate used in the present invention is mainly composed of dicarboxylic acid such as terephthalic acid or an ester derivative thereof (eg, lower alkyl ester, phenyl ester, etc.) and ethylene glycol or an ester derivative thereof (eg, monocarboxylic acid). And a repeating unit represented by the following formula [I] formed from a unit derived from a diol such as acid ester ethylene oxide.

[0015]

Embedded image

The (A) polyethylene terephthalate may contain units derived from dicarboxylic acids and / or diols other than those described above in an amount of 20 mol% or less, if necessary. Specific examples of such dicarboxylic acids other than terephthalic acid include phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. These can also be used as their ester derivatives.

Examples of diols other than ethylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol (propylene glycol), butanediol, pentanediol, neopentyl glycol, and hexamethylene glycol. And aliphatic diols such as dodecamethylene glycol and polyethylene glycol, and aromatic diols such as bisphenols and hydroquinone. These may be used as their ester derivatives.

Further, a combination of two or more of these may be used. The polyethylene terephthalate (A) used in the present invention is preferably composed of 10 units derived from diol.
When it is 0 mol%, units derived from a diol other than ethylene glycol may be contained in an amount of 0.1 to 3 mol%.

As such another diol, diethylene glycol is preferable. The (A) polyethylene terephthalate used in the present invention may be, if necessary,
Trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, trimethylolmethane,
A unit derived from a polyfunctional compound such as pentaerythritol may be contained in a small amount, for example, 2 mol% or less based on 100 mol% of the dicarboxylic acid component.

The intrinsic viscosity IV (measured in o-chlorophenol at 25 ° C.) of the polyethylene terephthalate (A) used in the present invention as described above is usually from 0.3 to 2.0.
dl / g, preferably 0.5 to 1.5 dl / g, more preferably 0.7 to 1.2 dl / g. Further, the melting point is usually 210 to 265 ° C, preferably 220 to 260 ° C.
The glass transition temperature is usually 50 to 120 ° C, preferably 60 to 100 ° C.

The polyethylene terephthalate (A) used in the present invention is produced from the above-mentioned dicarboxylic acid and diol by a conventionally known method. In the present invention,
As the polyethylene terephthalate (A), commercially available “raw polyethylene terephthalate” in the form of pellets is usually used. If necessary, “repropolyethylene terephthalate” may be used together with the raw polyethylene terephthalate. Specifically, (A) polyethylene terephthalate may contain "repropolyethylene terephthalate" in an amount of 1 to 50% by weight.

In the present specification, the "raw material polyethylene terephthalate" is produced in the form of pellets from a dicarboxylic acid and a diol, and is passed through a molding machine in a heated and molten state to form a hollow molded container or preform. Is a polyethylene terephthalate having no heat history. Further, "repropolyethylene terephthalate" is a polyethylene terephthalate having a heat history in which such a raw material polyethylene terephthalate has been heated and melted at least once and then passed through a molding machine to apply heat again to pelletize the polyethylene terephthalate. As described above, the process of “passing the raw material polyethylene terephthalate through a molding machine in a heated and molten state” is performed by heating and melting a pellet (chip) made of the raw material polyethylene terephthalate and forming the pellet into a desired shape such as a preform or a hollow molded container. Done. (B) Polypropylene Polypropylene has isotactic, in which all methyl groups are arranged on only one side of the extended chain, syndiotactic, in which methyl groups are alternately arranged on both sides of the chain, and disordered methyl groups. There are roughly three types of three-dimensional structures of atactics distributed in the above, and these are usually mixed.

The polypropylene used in the present invention is a syndiotactic polypropylene. The syndiotactic polypropylene used in the present invention is a polypropylene that substantially shows a syndiotactic structure, and if it has a substantially syndiotactic structure, even if it is a homopolymer of propylene, a small amount of propylene is used. May be a copolymer with olefins or dienes.

Examples of the small amount of olefins or dienes include ethylene, 1-butene, 3-methyl-1-butene,
1-hexene, vinylcyclohexene, 1-decene, 1
Olefins such as hexadecene, cyclopentene and norbornene, hexadiene, octadiene, decadiene, dicyclopentadiene, 5-ethylidene-2-
Dienes such as novonornene may be mentioned, and one or more of these may be copolymerized with polypropylene. The amount of the olefin or diene to be copolymerized is usually 20% or less, preferably 15% or less.

Intrinsic viscosity [η] of the syndiotactic polypropylene of the present invention (measured in decalin at 135 ° C.)
Is not particularly limited, but is usually 0.5 to 20
dl / g, preferably about 0.7 to 15 dl / g.

The syndiotactic pentad fraction of the syndiotactic polypropylene used in the present invention is as follows:
It is usually at least 0.5, preferably at least 0.6, particularly preferably at least 0.7. That is, by using a syndiotactic polypropylene having a syndiotactic pentad fraction of 0.5 or more, a molded article having particularly excellent transparency and heat resistance can be obtained.

The polypropylene having such a syndiotactic pentad fraction can be prepared by, for example, using isopropyl (cyclopentadiphenyl) (fluorenyl) zirconium chloride as a catalyst in a toluene solvent at a temperature of 20 to 80 ° C. It can be produced by polymerizing.

Polyester Resin Composition The polyester resin composition of the present invention comprises the above-mentioned (A) polyethylene terephthalate and (B) syndiotactic polypropylene, and (B) syndiotactic polypropylene is used in the composition. Usually 0.0
It is contained in an amount of 1 to 1000, preferably 0.05 to 500, more preferably 0.07 to 200 ppm.

By setting the amount of the (B) syndiotactic polypropylene within the above range, a stretched molded product, particularly a bottle having high gas barrier properties and transparency can be efficiently molded. Also, by allocating syndiotactic polypropylene in an amount within the above range,
The transparency of the resulting molded article may be higher than that of a bottle produced using polyethylene terephthalate alone.

From the (A) polyethylene terephthalate and (B) syndiotactic polypropylene, a polyester resin composition can be prepared by any known method. For example, a method in which (A) polyethylene terephthalate and (B) syndiotactic polypropylene are directly mixed and melt-kneaded by a mixer such as a tumbler blender or a Henschel mixer, or (A) polyethylene terephthalate and (B) The polyester resin composition is prepared by melt kneading syndiotactic polypropylene and (B) a masterbatch containing a high concentration of syndiotactic polypropylene, and then appropriately mixing the masterbatch with (A) polyethylene terephthalate. Things can be adjusted.

The polyester resin composition of the present invention as described above optionally contains other additives such as a coloring agent, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, and a lubricant. You may.

The intrinsic viscosity IV of the polyester resin composition of the present invention is generally 0.3 to 2.0 dl / g, preferably 0.5 to 1.5 dl / g, more preferably 0.7 to dl / g.
1.2 dl / g. A molded article formed from a polyester having such an intrinsic viscosity IV has excellent gas barrier properties, pressure resistance, and heat resistance.

The polyester resin composition of the present invention preferably has high transparency when molded, and the haze value measured by molding a square plate is usually 0.5 to 30%.
Preferably it is 1-20%.

Further, the polyester resin composition of the present invention preferably has a higher density when molded, since the pressure resistance becomes higher. The density is usually 1.34 to 1.40 at the time of molding.
g / cm ³ , preferably 1.35 to 1.39 g / cm ³
It is good.

The polyester resin composition of the present invention has an appropriate crystallization rate so that a hollow molded container such as a bottle can be efficiently produced. Specifically, the half-crystallization time is usually 30 to 300 seconds, preferably 60 to 200 seconds.

In a polyester resin composition containing a small amount of polypropylene in polyethylene terephthalate, it is presumed that polypropylene acts as a crystallization nucleus when polyethylene terephthalate is heated and crystallized by heating during blow molding. It is thought that the speed was increased.

In general, when other components are added to polyester for the purpose of imparting an additional function, the transparency at the time of molding is inferior to that of the original polyester, and the haze value at the time of molding becomes higher. Even when ordinary polypropylene was added to polyethylene terephthalate, the transparency was inferior to that in the case where only polyethylene terephthalate was molded, while maintaining transparency that would be acceptable for use.

However, by using the syndiotactic polypropylene, in the polyester resin composition of the present invention, the half-crystallization time of polyethylene terephthalate can be shortened to a range suitable for molding, and the transparency of the molded product can be reduced by using polyester. There is an unexpected effect that it is improved as compared with the case where it is used alone.

This is because the syndiotactic polypropylene has a much lower crystallization rate than conventional polypropylene, so that when polyethylene terephthalate is crystallized, the crystallization is more rapid than when only polyethylene terephthalate is crystallized. It is thought to be to inhibit.

<Hollow Molded Container> FIG. 1 shows an example of the hollow molded container of the present invention. For example, a hollow molded container made of the polyester of the present invention having such a shape can be produced by various methods generally used.

For example, the polyester of the present invention is melted, and the melt-plasticized polyester is extruded from a die head using a molding machine such as a screw rotation, a plunger extrusion, an accumulator or the like, and a parison (preform) is extruded. The hollow molded container of the present invention is sandwiched by a divided mold having a concave shape to be provided with a container shape, and the blow molded container of the present invention is formed by injection blow molding in which a pressurized fluid such as air is pressed into a heated parison to expand the parison. Obtainable.

Further, it can also be obtained by forming a parison from the polyester of the present invention, and then performing stretch blow molding of the parison at an area stretching ratio (product of longitudinal stretching ratio and transverse stretching ratio) of 6 to 15 times.

The parison in this case can also be manufactured by a conventionally known method such as injection molding and extrusion molding. In the present invention, the neck and neck of the parison may be heated and crystallized before the stretch blow molding, or the neck and neck of the hollow molded container obtained after the stretch blow molding may be heated and crystallized.

When forming a stretch-molded hollow container from a parison, the parison can be directly heated in a mold, and a blow fluid can be press-fitted and stretch-blown at the above-mentioned area draw ratio to form a hollow molded container. . Also, after a parison is stretch blown to form a hollow molded container once and cooled,
The hollow blow-formed container having the desired properties may be formed by performing stretch blow molding under heating while loading the mold. Examples of the blowing fluid include air, nitrogen, steam, and water, and among them, air is preferably used.

In the present invention, the hollow molded container thus obtained may be subjected to heat setting. Heat set, the obtained hollow molded container usually 100 ~ 200 ℃,
It can be carried out by holding the mold at a mold temperature of preferably 110 to 170 ° C., usually for 1 second or more, preferably 3 seconds or more. By heat setting the hollow molded container in this way, the density can be improved, and a hollow molded container with further increased strength such as pressure resistance can be obtained.

In the present invention, the blow-molded container subjected to injection blow molding or stretch blow molding and, if necessary, heat set, is taken out of the mold after cooling. As the cooling method employed here, an “internal cooling method” is used in which, for example, a cooled gas is blown into the inside of the hollow molded container to cool from the inside to the outside (outer surface) of the hollow molded container. Is preferred. When the hollow molded container is cooled from the inside (hollow portion) in this way, the hollow molded container can be taken out of the mold without causing deformation, shrinkage, and the like.

[0047]

Industrial Applicability The polyester resin composition of the present invention can produce a molded article excellent in gas barrier properties, heat resistance, transparency and pressure resistance with high productivity, and particularly produces a molded article excellent in transparency. Because it can be hollow molded container,
It can be widely used for packaging films. In addition, it is possible to obtain a hollow molded container which is hardly deformed even when filled with a heat-sterilized high-temperature beverage, and which does not impair the flavor of the contents even during long-term storage. In particular, according to the present invention, it is possible to produce a hollow molded article having higher transparency than when polyester is used alone.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<Measurement Method> [Semi-crystallization time (t _1/2 )] Measured using a differential scanning calorimeter (DSC) manufactured by PerkinElmer. 10 mg of the sample was weighed into a sample pan, heated from room temperature to 290 ° C. at a rate of 320 ° C./min, and held for 5 minutes. Then, cool to 30 ° C., hold for 5 minutes, and add 140
The temperature was raised to 320 ° C. at a rate of 320 ° C./min and maintained at this temperature. At this time, the relationship between the calorific value and time due to crystallization of the sample was measured, and the half-crystallization time (t _1/2 ) was determined as the time (second) required for the calorific value to reach half of the total calorific value. And [Intrinsic viscosity (IV)] A sample solution of 8 g / dl was prepared using an orthochlorophenol solvent, and the intrinsic viscosity (IV) was calculated from the solution viscosity measured at 25 ° C. [Transparency (haze value)] Dry sample at cylinder temperature 28
5m at a mold temperature of 10 ° C using an injection molding machine at 0 ° C
An m-thick square plate was molded, and the transparency of the molded product was compared by a haze value (light diffuse reflectance of white light). [Heat resistance] The hollow molded body was left under the condition of 40 ° C. and 90% humidity for one week, and then the hollow molded container was filled with hot water of 90 ° C. for 10 minutes, and the content before and after filling was measured. . From the contents before and after filling, the shrinkage ratio (5) was determined by the following equation.

[0050]

(Equation 1)

From the shrinkage (%) value thus obtained, the heat resistance was evaluated according to the following criteria. 〇: 0 ≦ shrinkage rate (%) <0.5 ×: 0.5 ≦ shrinkage rate (%) [Density] A liquid having a density adjusted with carbon tetrachloride and n-heptane is prepared in a cylinder, and a hollow molded container is prepared. A sample collected from the side of the sample was put into the sample, and the liquid density when the sample and the solution were hung was measured with a graduated hydrometer. [Appearance of hollow molded article] The haze value was measured at almost the center of the side surface of the hollow molded container. From the haze value, the appearance of the hollow molded article was evaluated as follows.

…: 0 ≦ Haze value (%) <5% ×: 5 ≦ Haze value (%) [Syndiotactic pentad fraction (rrrr)] The syndiotactic pentad fraction (rrrr) is ¹³ C
From Prrrr (the absorption intensity derived from the methyl group of the third unit in the site where five propylene units were continuously syndiotactically bonded) and Pw (the absorption intensity derived from all the methyl groups of the propylene unit) in the NMR spectrum, It is determined by the following equation (2).

[0053]

(Equation 2)

The NMR measurement is performed, for example, as follows. That is, 0.35 g of a sample is dissolved in 2.0 ml of hexachlorobutadiene by heating. After the solution is filtered through a glass filter (G2), 0.5 ml of deuterated benzene is added, and the solution is charged into an NMR tube having an inner diameter of 10 mm. Then, ¹³ C NMR measurement is performed at 120 ° C. by using a JX-GX-500 type NMR measuring apparatus. The number of integration is 10,000 or more.

[0055]

Example 1 Intrinsic viscosity [IV] = 0.775 dl / g,
Diethylene glycol content: 1.33% by weight of polyethylene terephthalate (A) and a metallocene catalyst produced by a liquid phase polymerization method, a syndiotactic pentad fraction of 0.77 and an intrinsic viscosity [η] of about 2.1 dl / g. A polyester resin composition containing the syndiotactic polypropylene (B) in an amount of 10 ppm (parts by weight) was obtained.

The polyester resin composition was melted and injection-formed to form a square plate, and the transparency and crystallization rate of the square plate were measured. Next, a hollow molded container was molded from the polyester resin composition as described below.

Injection molding machine M-100A (manufactured by Meiki Seisakusho)
Cylinder set temperature 280 ° C, mold temperature 10 ° C
Under the conditions described above, a preform having a diameter of 28 mm was formed. Plug the plug part of the obtained preform into an oil bath.
After crystallization by heating at 70 ° C. for 5 minutes, the body and bottom of the preform were softened by heating at 110 ° C.

Next, the preform was molded using a molding machine (model number: LB01; manufactured by CORPOPLAST).
Stretch-blow molding was performed at a stretching temperature of 110 ° C. and a blow mold temperature of 150 ° C. to form a 1.5-liter hollow molding container.

The heat resistance, density and appearance of this hollow molded container were evaluated as described above. Table 1 shows the results.

[0060]

Example 2 A polyester resin composition was obtained in the same manner as in Example 1, except that the content of the syndiotactic polypropylene (B) was changed to 30 ppm (parts by weight).

Using this, a square plate was formed in the same manner as in Example 1, and the transparency and the crystallization speed were measured. Further, a hollow molded container was molded in the same manner as in Example 1 to evaluate heat resistance, density and appearance. Table 1 shows the results.

[0062]

Example 3 A polyester resin composition was obtained in the same manner as in Example 1, except that the blending amount of syndiotactic polypropylene (B) was changed to 100 ppm (parts by weight).

Using this, a square plate was formed in the same manner as in Example 1, and the transparency and the crystallization speed were measured. Further, a hollow molded container was molded in the same manner as in Example 1 to evaluate heat resistance, density and appearance. Table 1 shows the results.

[0064]

Example 4 A polyester resin composition was obtained in the same manner as in Example 1, except that the amount of the syndiotactic polypropylene (B) was changed to 0.1 ppm (parts by weight).

Using this, a square plate was formed in the same manner as in Example 1, and the transparency and the crystallization speed were measured. Further, a hollow molded container was molded in the same manner as in Example 1 to evaluate heat resistance, density and appearance. Table 1 shows the results.

[0066]

Comparative Example 1 A polyester resin composition was obtained in the same manner as in Example 1, except that the amount of the syndiotactic polypropylene (B) was changed to 10,000 ppm (parts by weight).

Using this, a square plate was formed in the same manner as in Example 1, and the transparency and the crystallization rate were measured. Further, a hollow molded container was molded in the same manner as in Example 1 to evaluate heat resistance, density and appearance. Table 1 shows the results.

[0068]

Comparative Example 2 A polyester resin composition was obtained in the same manner as in Example 1, except that syndiotactic polypropylene (B) was changed to polypropylene (b).

The polypropylene (b) is an isotactic polypropylene composed of 95% isotactic and 0.5% atactic. Using this, a square plate was formed in the same manner as in Example 1, and the transparency and the crystallization speed were measured.

Further, a hollow molded container was molded in the same manner as in Example 1, and the heat resistance, density and appearance were evaluated. Table 1 shows the results
Shown in

[0071]

Comparative Example 3 In Example 1, the syndiotactic polypropylene (B) was changed to the polypropylene (b) described in Comparative Example 2, and the polypropylene content was 100 ppm.
(Parts by weight) A polyester resin composition was obtained in the same manner except that the composition was changed to (parts by weight).

Using this, a square plate was formed in the same manner as in Example 1, and the transparency and the crystallization speed were measured. Further, a hollow molded container was molded in the same manner as in Example 1 to evaluate heat resistance, density and appearance. Table 1 shows the results.

[0073]

Comparative Example 4 In Example 1, the polypropylene (B) was used.
Was not included, and a square plate composed only of polyethylene terephthalate (A) was formed, and the transparency and the crystallization rate were measured.

Further, a hollow molded container was molded in the same manner as in Example 1, and the heat resistance, density and appearance were evaluated. Table 1 shows the results
Shown in

[0075]

As shown in the above examples, the polyester resin composition of the present invention is excellent in all of gas barrier properties, heat resistance, pressure resistance and transparency, and particularly excellent in transparency. Further, a hollow molded container using the same has good properties of gas barrier properties, heat resistance, pressure resistance and transparency, and also has a good balance of these properties.

[0076]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a polyester hollow molded container according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hollow molded container 2 ... Mouth and neck part 3 ... Upper shoulder part 4 ... Body part 5 ... Bottom part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 1/09 B65D 1/00 A // (C08L 67/02 23:10) B29K 67:00 B29L 22: 00 F term (reference) 3E033 AA01 BA16 CA03 CA07 CA16 CA18 DA03 DB01 DD02 DD05 FA02 FA03 GA02 4F201 AA24 AB15 AB19 AG07 AH55 BA03 BC02 BC12 BD04 BD05 BD06 BM05 BM06 4F208 AA24 AB15 AB19 AG07 AH55 LA01 LA08 LB01 L22 LG03 AB15 AB19 AG07 AH55 QA01 QC07 QG04 4J002 BB122 BB142 CF061 CF071 GG01

Claims (6)

[Claims] 1. A polyethylene phthalate comprising a repeating unit derived from (A) a dicarboxylic acid containing terephthalic acid and / or an ester-forming derivative thereof, and a diol containing ethylene glycol and / or an ester-forming derivative thereof; A) a polyester resin composition comprising: syndiotactic polypropylene, wherein the composition comprises the syndiotactic polypropylene (B) in an amount of 0.01 to 1000 ppm. 2. The syndiotactic polypropylene (B) has a syndiotactic pentad fraction of 0.5.
The polyester resin composition according to claim 1, wherein: 3. A polyethylene phthalate comprising a repeating unit derived from a dicarboxylic acid containing terephthalic acid and / or an ester-forming derivative thereof, and a diol containing ethylene glycol and / or an ester-forming derivative thereof, and (B) ) A composition comprising syndiotactic polypropylene, wherein the composition is formed from a polyester resin composition containing the syndiotactic polypropylene (B) in an amount of 0.01 to 1000 ppm. A preform characterized by: 4. The syndiotactic polypropylene (B) has a syndiotactic pentad fraction of 0.5.
4. The preform according to claim 3, wherein: 5. A polyethylene phthalate comprising a repeating unit derived from a dicarboxylic acid containing terephthalic acid and / or an ester-forming derivative thereof, and a diol containing ethylene glycol and / or an ester-forming derivative thereof, and (B) A) a preform formed from a polyester resin composition wherein the syndiotactic polypropylene (B) is contained in the composition in an amount of 0.01 to 1000 ppm. A hollow molded container obtained by stretch-molding. 6. The syndiotactic polypropylene (B) having a syndiotactic pentad fraction of 0.5.
6. The hollow molded container according to claim 5, wherein: