JP2003327808A - Polyester resin composition and blow molded product composed of the same composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin composition excellent in heat resistance, transparency and mechanical properties, having very slight AA (acetaldehyde) content and excellent in long-term moldability, etc., and capable of forming a thermoplastic polyester molded product, a blow molded product and a film, preliminary molded products thereof and molded products thereof and to provide the blow molded product composed of the resin composition. <P>SOLUTION: The polyester resin composition comprises (A) an aromatic polyester having a recurring unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, (B) a hindered phenol-based compound represented by general formula (1). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester resin composition which is preferably used as a raw material for molded articles such as hollow molded containers such as beverage bottles, films and sheets, and in particular, hollow molded articles. Polyester resin composition that gives a hollow molded product that has good mold releasability from the heat treatment mold during molding, excellent long-term continuous moldability, transparency and heat-resistant dimensional stability, and a low acetaldehyde content. It is about things.

[0002]

2. Description of the Related Art Polyethylene terephthalate resin is used as a material for containers such as carbonated drinks, juices and mineral waters due to its excellent transparency, mechanical strength, heat resistance and gas barrier property. Has been done. However, in recent years, there has been a demand for a material having a more excellent characteristic than a container made of polyethylene terephthalate resin, which is excellent in heat resistance and gas barrier property. In order to meet such requirements, heat resistance than polyethylene terephthalate resin,
The use of a polyethylene naphthalate resin, which has a low gas barrier property and a low acetaldehyde content and is excellent in moldability for a long period of time, has been studied. JP-A-52-
Japanese Patent No. 45466 describes a hollow container made of polyethylene naphthalate having excellent heat resistance and gas barrier properties. Further, JP-A-2-217222 discloses a polyethylene naphthalate bottle highly stretched to have a stretching index of 130 cm or more and a method for producing the same. However, in the case of polyethylene naphthalate resin, it is difficult to mold, and a hollow molded body having excellent transparency and a uniform wall thickness distribution has not been obtained. Further, JP-A-64-85732 discloses 2,6-naphthalene-dicarboxylic acid components 65 to 9
A heat-resistant bottle made of polyethylene naphthalate copolymer having 8.5 mol% and other dicarboxylic acid components (terephthalic acid, isophthalic acid, etc.) 35 to 1.5 mol% and ethylene glycol as a main glycol component Have been described. However, when the content of the third component is 10 mol% or more, the melt-polymerized resin does not exhibit a melting point, and the crystallization rate becomes extremely slow, making it impossible to crystallize under practical conditions. Increase in molecular weight and acetaldehyde (AA, hereinafter acetaldehyde is abbreviated as AA)
Solid-state polymerization treatment for the purpose of lowering the content is impossible.

On the other hand, in recent years, polyethylene terephthalate
The polyester container centered on the
It has come to be used as a container for low-flavor beverages such as tao and oolong tea. Various measures have been taken to reduce the acetaldehyde content in these polyester moldings. Generally, a method of lowering the AA content by solid-phase polymerizing a melt-polycondensed polyester, a method of lowering AA generation at the time of molding by using a copolyester having a lower melting point, and a method of thermoforming at the time of thermoforming A method of reducing the molding temperature as much as possible and a method of minimizing the shear stress during thermoforming are used. However, it has been found that the flavor and odor of the contents of these containers cannot be improved only by reducing the AA content in the material of the polyester molded body by the above method. Further, for example, a method of using a polyester composition in which 0.05 parts by weight or more and less than 1 part by weight of a metaxylylene group-containing polyamide resin is added to 100 parts by weight of a polyester resin (Japanese Patent Publication No. 6-6662) and heat treatment. A polyester container (Japanese Patent Publication No. 4-71425) made of a polyester composition in which a specific polyester having a terminal amino group concentration regulated to a certain range is contained in a plastic polyester has been proposed, but mineral water, etc. It has been found that there are cases where it is insufficient as a material for a container for low-flavor beverages.

[0004]

The object of the present invention is to provide excellent heat resistance, transparency and mechanical properties, and also to achieve a very high AA.
Thermoplastic polyester molded product, hollow molded product, film having a small content and excellent in long-term moldability, a preformed product relating to these, a polyester resin composition capable of forming these molded products, and a hollow molded product comprising the same Is to provide.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that an aromatic polyester (A) having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component. And the molecular weight is 25
With a polyester resin composition consisting of 0 or more of the hindered phenolic compound (B) described in the general formula (1) and a metaxylylene group-containing polyamide resin (C), the acetaldehyde content is 40 ppm or less, and the heat resistance, It has been found that a polyester resin composition having both transparency and long-term moldability and a hollow molded article made thereof can be obtained.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin composition of the present invention having the above-mentioned constitution can be melt-molded to easily form a long-term molded product having excellent transparency and heat-resistant dimensional stability, particularly hollow molding of containers and the like. A polyester resin composition capable of obtaining a polymer, which is mainly composed of a repeating unit consisting of an aromatic dicarboxylic acid component and a glycol component, and preferably further contains a metaxylylene group-containing polyamide resin (C). By using a resin composition and a hollow molded article made of the same, and further using catalyst deactivation by conventional water treatment, it is possible to obtain a polyester resin composition in which AA of the molded article is reduced as compared with the conventional water treatment active resin. it can.

[0007]

[Chemical 2]

(R10, R11, R12 in the formula (1),
R13 and R14 may be the same or different and have 1 to 3 carbon atoms.
0 represents alkyl and / or phenyl and / or cycloalkyl. )

In this case, the aromatic polyester (A) may be one having an acetaldehyde content of 40 ppm or less and having a repeating unit mainly composed of a terephthalic acid component and an ethylene glycol component.

In this case, the density of the aromatic polyester having a repeating unit mainly composed of a terephthalic acid component and an ethylene glycol component is 1.3.
It can be 7 g / cm ³ or more.

In this case, the intrinsic viscosity of the aromatic polyester having a repeating unit mainly composed of a terephthalic acid component and an ethylene glycol component is
It can be 0.55-1.30 deciliters / gram.

Further, in this case, the polyester resin composition formed into a chip shape after polymerization is treated with treated water satisfying the following conditions (a) and (b) in a treatment tank. be able to. (A) Temperature 40 to 120 ° C. (b) Treated water including wastewater from the treatment tank

When the above polyester resin composition was melted at 290 ° C. for 60 minutes, the acetaldehyde content was W1 pp.
When the acetaldehyde content without melting treatment is set to W0ppm for 60 minutes at 290 ℃, ΔW = W1-W0 and ΔW is 50pp
A polyester resin composition that can be m or less.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the polyester resin composition of the present invention will be specifically described below.

The aromatic polyester (A) used in the present invention is a crystalline polyester mainly composed of an aromatic dicarboxylic acid component and a glycol component, and preferably the aromatic dicarboxylic acid component contains 85 mol% or more of the acid component. It is a crystalline polyester, more preferably a crystalline polyester in which the aromatic dicarboxylic acid component contains 95 mol% or more of the acid component. Examples of typical aromatic polyesters include polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, and copolymers obtained by copolymerizing a part thereof with other dicarboxylic acid component or glycol component. it can.

The aromatic dicarboxylic acid component constituting the aromatic polyester (A) used in the present invention includes terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4-dicarboxylic acid and diphenoxyethanedicarboxylic acid. And aromatic dicarboxylic acids and functional derivatives thereof.

The glycol component constituting the aromatic polyester (A) used in the present invention includes aliphatic glycols such as ethylene glycol, trimethylene glycol, tetramethylene glycol and neopentyl glycol, and fats such as cyclohexanedimethanol. Examples thereof include cyclic glycols.

The aromatic polyester (A) having a repeating unit mainly composed of a terephthalic acid component and an ethylene glycol component, which is preferably used in the present invention, is preferably a linear polyester containing 85 mol% or more of ethylene terephthalate unit. , And more preferably an aromatic polyester composed of polyethylene terephthalate.

Examples of the dicarboxylic acid used by copolymerization in the aromatic polyester (A) include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid. Acids, aromatic dicarboxylic acids such as diphenoxyethanedicarboxylic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, glutaric acid, Aliphatic dicarboxylic acids such as dimer acid and functional derivatives thereof,
Examples thereof include alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid, and functional derivatives thereof.

Specific examples of the glycol component which is copolymerized in the aromatic polyester (A) include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1-butanediol. , 5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-
Diethyl-1,3-propanediol, 2-butyl-2
-Ethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol and the like can be mentioned. As the alicyclic glycol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,
1,2-Cyclohexanedimethanol, 3,8-bisbidroxymethyltricyclodisican, hydrogenated bisphenol A, hydrogenated bisphenol F, TCD glycol and the like can be mentioned, and these can be used alone or in combination of two or more kinds.

A carboxylic acid may be added to the aromatic polyester (A) within a range not impairing the content of the present invention.
As a method for introducing a carboxyl group, trimellitic anhydride, phthalic anhydride, pyromellitic anhydride, succinic anhydride, 1,8
-Naphthalic acid, 1,2-cyclohexanedicarboxylic acid anhydride, etc. are post-added to give an acid value. Examples of the modified polyester include a method of chain extension with dimethylolpropionic acid, dimethylolbutanoic acid and the like.

Further, as other copolymerization components used by copolymerization in the aromatic polyester (A) used in the present invention, a polyfunctional compound, an acid component such as trimellitic acid, pyromellitic acid, etc. Examples of the glycol component include glycerin and pentaerythritol. The amount of the above copolymerization components used is
It should be such that the aromatic polyester (A) remains substantially linear.

The melt polycondensation reaction of the aromatic polyester resin (A) may be carried out in a batch type reaction apparatus or a continuous reaction apparatus. In any of these methods, the melt polycondensation reaction may be carried out in one step or may be carried out in multiple steps. The solid phase polymerization reaction can be carried out by a batch type apparatus or a continuous type apparatus as in the melt polycondensation reaction. The melt polycondensation and solid phase polymerization may be carried out continuously or may be carried out separately.

In the case of the direct esterification method, compounds of Ge, Sb and Ti are used as the polycondensation catalyst, and it is particularly convenient to use the Ge compound or a mixture thereof with the Ti compound.

As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or a slurry of ethylene glycol, a solution of crystalline germanium dioxide dissolved in water by heating or a solution of ethylene glycol added thereto and subjected to heat treatment is used. However, in particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved in water by heating or a solution in which ethylene glycol is added and heated. These polycondensation catalysts can be added during the esterification process. When a Ge compound is used, the amount used is preferably 10 to 150 as the residual Ge amount in the polyester resin.
ppm, more preferably 13 to 100 ppm, still more preferably 15 to 70 ppm.

Examples of the Ti compound include tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate and tetra-n-butyl titanate, and their partial hydrolysis. Examples thereof include titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, calcium titanyl oxalate, titanyl oxalate compounds such as strontium titanyl oxalate, titanium trimellitate, titanium sulfate, titanium chloride and the like. The Ti compound is a formed polymer.
The amount of remaining Ti in the medium is preferably added so as to fall within a range of 0.1 to 10 ppm.

As the Sb compound, antimony trioxide,
Antimony acetate, antimony tartrate, potassium antimony tartrate, antimony oxychloride, antimony glycolate
, Antimony pentoxide, triphenylantimony, and the like. The Sb compound is added so that the amount of Sb remaining in the produced polymer is preferably in the range of 50 to 250 ppm.

As the stabilizer, it is preferable to use phosphoric acid, polyphosphoric acid, phosphoric acid esters such as trimethyl phosphate, and the like. These stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the amount of P remaining in the produced polymer is preferably in the range of 5 to 100 ppm.

Also, in order to control the DEG content in the polyester, a basic compound such as, for example,
Tertiary amines such as triethylamine and tri-n-butylamine, quaternary ammonium salts such as tetraethylammonium hydroxide and the like can be added.

Further, solid phase polymerization may be carried out in order to increase the intrinsic viscosity of the aromatic polyester (A) and reduce the AA content.

In the present invention, the intrinsic viscosity of the aromatic polyester (A) forming the chip (a) of the aromatic polyester (A) having a repeating unit composed mainly of a terephthalic acid component and an ethylene glycol component has an intrinsic viscosity of 0. 5
It is preferably 5-1.30 deciliter / gram, more preferably 0.58-1.00 deciliter / gram, and even more preferably 0.6-0.9 deciliter / gram. When the intrinsic viscosity of the polyester chip (a) is less than 0.55 deciliter / gram, the molded product obtained by melt-molding the polyester resin composition of the present invention has transparency, heat resistance, mechanical properties, etc. It may not be fully satisfied. In addition, the acetaldehyde content of the molded product tends to increase as the intrinsic viscosity exceeds 1.30 deciliters / gram, making it unsuitable for use in beverage bottles.

The hindered phenol compound (B) represented by the general formula (1) used in the present invention is preferably 10 parts by weight or less with respect to the aromatic polyester (A) of the present invention, and is preferable. Is 5 parts by weight or less, more preferably 2 parts by weight or less and most preferably 0.5 parts by weight.
When it exceeds the weight part, haze tends to decrease, and 0.0
If the amount is 001 parts by weight or less, the effect of reducing AA and ΔW tends to decrease.

The hindered phenol compound represented by the general formula (1) used in the present invention has a molecular weight of 25.
It is preferably 0 or more, and when the molecular weight is 250 or less, the adhesion of the hindered phenolic compound to the surface of the heating die rapidly increases, and the transparency of the obtained hollow molded article tends to be extremely deteriorated.

The method for adding the hindered phenolic compound (B) represented by the general formula (1) used in the present invention to the polyester resin composition is as follows: [I] The aromatic polyester used in the present invention ( A)
Or a method of performing melt mixing or dry blending with the polymer at an arbitrary time during the polymerization (method of adding at the time of esterification and / or completion of esterification and / or at the time of polycondensation). [II] A raw material of the metaxylylene group-containing polyamide (C) used in the present invention before polymerization, a method of adding during polymerization, or a method of melt-mixing or dry-blending with the polymer. [III] A method in which the aromatic polyester (A) and the metaxylylene group-containing polyamide (C) used in the present invention are melt-mixed and then dry-blended. [IV] A method in which the aromatic polyester (A) used in the present invention, the hindered phenolic compound (B) represented by the general formula (1) and the metaxylylene group-containing polyamide (C) are melt-mixed or dry-blended at the same time. Etc.

The metaxylylene group-containing polyamide resin (C) used in the present invention is a metaxylylenediamine or a mixed xylylenediamine and a dicarboxylic acid containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine. At least 70 mol% or more, more preferably 75 mol% in the molecular chain of the structural unit generated from
It is a polyamide resin containing not less than mol%, particularly preferably not less than 80 mol%.

Examples of the dicarboxylic acid as a copolymerization component include adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, undecanoic acid, undecadioic acid, dodecanedioic acid and dimer. Aliphatic dicarboxylic acids such as acids, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, xylylenedicarboxylic acid, and naphthalenedicarboxylic acid can be used.

As the diamine component as a copolymerization component, ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nona. Aliphatic diamines such as methylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, cyclohexanediamine, bis-
Alicyclic diamines such as (4,4′-aminohexyl) methane and aromatic diamines such as para-bis- (2-aminoethyl) benzene can be used. These dicarboxylic acids and diamines can be used alone or in combination of two or more at an arbitrary ratio.

In addition to the above diamines and dicarboxylic acids, lactams such as ε-caprolactam and laurolactam, aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid, and aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid. An acid or the like can also be used as a copolymerization component. In particular, the use of ε-caprolactam is desirable.

Examples of these polymers are homopolymers such as polymeta-xylylene adipamide, poly-meta-xylylene sebacamide, poly-meta-xylylene speramide, and meta-xylylene diamine / adipic acid / isophthalic acid copolymer. Examples thereof include a combination, a metaxylylene / paraxylylene adipamide copolymer, a metaxylylene / paraxylylene piperamide copolymer, a metaxylylene / paraxylylene azeramide copolymer, and the like.

The above-mentioned metaxylylene group-containing polyamide resin (C) is a method of reacting an aqueous solution of an aminocarboxylic acid salt formed from a diamine and a dicarboxylic acid by heating under pressure and atmospheric pressure or reacting the diamine and dicarboxylic acid under atmospheric pressure. It can be produced by a method of directly reacting by heating. Further, by solid-phase polymerizing the polyamide chips obtained by these melt polycondensation reactions, it is possible to obtain a metaxylylene group-containing polyamide having a higher viscosity. The polycondensation reaction of the above-mentioned metaxylylene group-containing polyamide resin (C) may be carried out in a batch reactor or a continuous reactor.

Usually, in the production of the metaxylylene group-containing polyamide resin (C), a phosphorus-based stabilizer is often added and polymerized in order to prevent gelation due to heat deterioration. When the phosphorus atom content in the metaxylylene group-containing polyamide (C) used in the present invention is X, 0.01 ≦
It is preferable that X ≦ 400 ppm. The lower limit is more preferably 0.1 ppm, even more preferably 1 ppm, particularly preferably 3 ppm,
Most preferably, it is 5 ppm. The upper limit is preferably 35
It is 0 ppm, more preferably 300 ppm.
When X is less than 0.01 ppm, burn streaks and unmelted substances are likely to occur when a heat resistant hollow molded article is produced using the polyester composition. In addition, heat deterioration during molding is large, and the effect as a stabilizer cannot be found. On the other hand, X is 4
When it is more than 00 ppm, the thermal stability is excellent, but the transparency of the obtained hollow molded article may be deteriorated. In particular, S
When the b-based compound is added to the polymerization catalyst or the polyester resin used as the additive, darkening that seems to be derived from the metal Sb occurs, and transparency may be significantly deteriorated.

As the phosphorus atom-containing compound in the metaxylylene group-containing polyamide resin (C), at least one selected from compounds represented by the following chemical formulas (C-1) to (C-4) is used. It is preferable.

[0043]

[Chemical 3]

[0044]

[Chemical 4]

[0045]

[Chemical 5]

[0046]

[Chemical 6]

(Wherein R1 to R7 are hydrogen, an alkyl group, an aryl group, a cycloalkyl group or an arylalkyl group, X1 to X5 are hydrogen, an alkyl group, an aryl group,
(A cycloalkyl group, an arylalkyl group or an alkali metal, or one of X1 to X5 and R1 to R7 in each formula may be linked to each other to form a ring structure.)

Examples of the phosphinic acid compound represented by the chemical formula (C-1) include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite,
Potassium hypophosphite, lithium hypophosphite, ethyl hypophosphite,

[0049]

[Chemical 7]

Or

[Chemical 8] Compounds and their hydrolysates, and condensates of the above phosphinic acid compounds.

Examples of the phosphonous acid compound represented by the chemical formula (C-2) include phenylphosphonous acid, sodium phenylphosphonous acid, potassium phenylphosphonous acid,
Examples include lithium phenylphosphonite and ethyl phenylphosphonous acid.

Examples of the phosphonic acid compound represented by the chemical formula (C-3) include phenylphosphonic acid, ethylphosphonic acid,
Examples include sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate, and the like.

Examples of the phosphite compound represented by the chemical formula (C-4) include phosphorous acid, sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, and pyrophosphorous acid. and so on.

It was also found that the thermal stability of the polyester composition of the present invention is further improved by adding an alkali compound represented by the following chemical formula (D). Z-OR8 (D) (However, Z is an alkali metal, R8 is hydrogen, an alkyl group, an aryl group, a cycloalkyl group, -C (O) C.
H ₃ or -C, (O) OZ ', (Z' is hydrogen, an alkali metal))

The alkaline compound represented by the chemical formula (D) includes sodium hydroxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium acetate, sodium carbonate, and Examples thereof include alkaline earth compounds containing an alkaline earth metal, but are not limited to these compounds.

The content of the alkali compound in the metaxylylene group-containing polyamide resin (C) used in the present invention is preferably 1.5 to 6.0 times the phosphorus atom content (X). It is more preferably 1.8 to 5.5 times, still more preferably 2.0 to 5.0 times. When the content of the alkali compound is less than 1.5 times the phosphorus atom content (X), gelation is likely to be promoted. On the other hand, when the content of the alkali compound is more than 6.0 times the phosphorus atom content (X), the polymerization rate becomes slow, the viscosity does not sufficiently increase, and gelation is promoted particularly in a reduced pressure system, which is uneconomical. is there.

The above chemical formulas (C-1) to be used in the present invention
The compound represented by (C-4) and the compound represented by the chemical formula (D) may be used alone, but it is particularly preferable to use them in combination.
Books are preferred because they improve the thermal stability of the polyester resin composition of the nail. In addition to the compounds described above, conventionally known antioxidants, ultraviolet absorbers, weathering agents, matting agents, lubricants, viscosity stabilizers, etc. are used to impair the flavor retention, gas barrier properties, and transparency of the hollow molded article. It may be used in combination to the extent that it does not exist.

To blend the above-mentioned phosphorus atom-containing compound into the metaxylylene group-containing polyamide resin (C) used in the present invention, the raw material of the polyamide before polymerization, addition during polymerization, or melt-mixing with the polymer is carried out. May be.

The tertiary nitrogen content of the metaxylylene group-containing polyamide resin (C) used in the present invention is preferably 2.0 mol% or less, more preferably 1.5 mol% or less,
More preferably, it is 1.0 mol% or less. A molded body obtained by using a polyester resin composition containing a metaxylylene group-containing polyamide resin (C) having a tertiary nitrogen content of more than 2.0 mol% contains a colored foreign substance due to a gelled product, and has a color May get worse. In particular, in a stretched film or a biaxially stretched hollow molded product obtained by stretch molding, the portion where the gel-like material is present is not normally stretched and becomes thick, which causes thickness unevenness and has no commercial value. May increase.

The lower limit of the content of tertiary nitrogen is preferably 0.001 mol%, more preferably 0.01 mol%, particularly preferably 0.05 mol%, for manufacturing reasons. When producing a metaxylylene group-containing polyamide resin having a tertiary nitrogen content of 0.001 mol% or less, a highly purified raw material is used, a large amount of a deterioration inhibitor is required, and the polymerization temperature is lowered. There may be a productivity problem such as the need to keep.

The tertiary nitrogen mentioned here is both nitrogen based on an imino compound and nitrogen based on a tertiary amide, and the content of the tertiary nitrogen is such that the secondary amide (--NHCO--:
It is the content represented by the molar ratio (mol%) to nitrogen based on the usual amide constituting the main chain).

The relative viscosity of the metaxylylene group-containing polyamide resin (C) used in the present invention is preferably 1.3 to 4.0, the lower limit is more preferably 1.6, still more preferably 1.7, and particularly preferably 1 The upper limit is more preferably 3.7, still more preferably 1.3.5, and particularly preferably 3.0. When the relative viscosity is 1.3 or less, the molecular weight is too small, and the mechanical properties of the molded product made of the polyester resin composition of the present invention may be poor. On the other hand, when the relative viscosity is 4.0 or more, it takes a long time to polymerize the polyamide resin, which may cause deterioration of the polymer or undesired coloring, and also cause a decrease in productivity and a cost increase factor. May be.

The shape of the metaxylylene group-containing polyamide resin (C) used in the present invention is as follows:
The shape may be any of a mold, a square shape, a spherical shape, or a flat plate shape. The average particle size is usually 1.0 to 5 mm, preferably 1.2 to
It is 4.5 mm, more preferably 1.5 to 4.0 mm. For example, in the case of a cylinder type, the length is 1.
It is practical that the diameter is 0 to 4 mm and the diameter is about 1.0 to 4 mm. In the case of spherical particles, it is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. The weight of the tip is 1
The range of 0 to 30 mg / piece is practical.

The density of the metaxylylene group-containing polyamide resin (C) used in the present invention is 1.20 to 1.24 m.
g / cm ³ is preferable, more preferably 1.20 mg /
cm ³ or more and 1.23 mg / cm ³ or less.

The amount of the metaxylylene group-containing polyamide resin (C) constituting the polyester resin composition of the present invention is 0.01 to 100 parts by weight based on 100 parts by weight of the aromatic polyester (A). Is preferred. When it is desired to obtain a molded product having a very low AA content from the polyester resin composition, the addition amount of the metaxylylene group-containing polyamide resin (C) is 0 based on 100 parts by weight of the aromatic polyester (A). 0.01-5 parts by weight is preferable, a more preferable lower limit is 0.1 part by weight, a still more preferable lower limit is 0.5 part by weight, a more preferable upper limit is 4 parts by weight, and a still more preferable upper limit is 3 parts by weight.

When it is desired to obtain a molded product having excellent gas barrier properties and transparency which does not impair practicality,
1 to 100 parts by weight is preferable with respect to 100 parts by weight of the aromatic polyester (A), and a more preferable lower limit is 3
Parts by weight The more preferred lower limit is 5 parts by weight, the more preferred upper limit is 60 parts by weight, and the still more preferred upper limit is 30 parts by weight. Metaxylylene group-containing polyamide resin (C)
When the mixing amount of the above is less than 0.01 parts by weight with respect to 100 parts by weight of the aromatic polyester (A), the AA content of the obtained molded product is not reduced, and the flavor retention of the molded product contents is maintained. Can be very bad. Further, when the mixing amount of the metaxylylene group-containing polyamide resin (C) exceeds 100 parts by weight with respect to 100 parts by weight of the aromatic polyester (A), the transparency of the obtained molded product may be very poor. In addition, the mechanical properties of the molded product may be deteriorated.

The polyester resin composition of the present invention is 29
ΔW is 50ppm when melted at 0 ℃ for 60 minutes
Or less, preferably 40 ppm or less, more preferably 3
It is 0 ppm or less. When hollow molding is performed using a polyester resin composition having a ΔW of more than 51 ppm, it becomes unsuitable for use in beverage bottles.

The polyester resin composition of the present invention contains a cyclic trimer, and its content is 0.45% by weight or less, preferably 0.33% by weight or less, more preferably 0.30% by weight or less. Is. When a heat-resistant hollow molded article is molded from the polyester resin composition of the present invention, heat treatment is carried out in a heating mold. When the content of the cyclic trimer is 0.45% by weight or more, the heating mold is heated. The oligomer adhesion to the mold surface rapidly increases, and the transparency of the obtained hollow molded article tends to be extremely deteriorated.

The polyester resin composition of the present invention is 29
The amount of increase of the cyclic trimer when melted at a temperature of 0 ° C. for 60 minutes is 0.50% by weight or less, preferably 0.30% by weight or less, and more preferably 0.20% by weight or less. When hollow molding is performed using a polyester resin composition in which the amount of increase in cyclic trimer exceeds 0.50% by weight, oligomers such as cyclic trimer may cause an inner surface of the mold, a gas exhaust port of the mold, and an exhaust pipe. To obtain a transparent hollow molded container that adheres to the mold, the mold must be frequently cleaned.

The polyester resin composition of the present invention in which the amount of the cyclic trimer increased when melted at a temperature of 290 ° C. for 60 minutes is 0.50% by weight or less is obtained after melt polycondensation or solid phase polymerization. It can be produced by deactivating the polycondensation catalyst of the polyester.

As a method for deactivating the polycondensation catalyst of the aromatic polyester (A), a method of contact-treating the aromatic polyester chips with water, steam or a gas containing steam after the melt polycondensation or after the solid phase polymerization is carried out. Is mentioned.

A method of contacting the aromatic polyester chips with water, steam or a gas containing steam to achieve the above object will be described below.

The shape of the aromatic polyester chips may be any of a cylinder type, a square type, a flat plate type, etc., and the size thereof is usually from 1.8 to 8 The range is 4 mm, preferably 2 to 4 mm.
For example, in the case of a cylinder type, it is practical that the length is 2 to 4 mm and the diameter is about 2 to 4 mm.

Examples of the hot water treatment method include a method of immersing in hot water and a method of spraying water on the chips with a shower. The treatment time is 5 minutes to 2 days, preferably 10 minutes to 1 day, more preferably 30 minutes to 10 hours, and the temperature of water is 20 to 180 ° C., preferably 40 to 150.
C., more preferably 50 to 120.degree.

The method for industrially treating water will be illustrated below, but the method is not limited to this. The treatment method may be either a continuous method or a batch method, but the continuous method is preferable for industrial use.

When the chips of the aromatic polyester (A) are treated with water in a batch system, a silo type treatment tank is used. That is, the chips of the aromatic polyester (A) are received in a silo by a batch method and treated with water. Alternatively, the aromatic polyester (A) chips may be received in a rotating tubular processing tank, and water treatment may be performed while rotating to make the contact with water more efficient.

When the chips of the aromatic polyester (A) are treated with water continuously, the chips of the aromatic polyester (A) are continuously or intermittently received from the upper part in a tower type treatment tank to treat the water. Can be made.

When the chips of the aromatic polyester (A) are contacted with steam or a steam-containing gas, the steam or steam-containing gas or steam-containing gas at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C. Air is preferably supplied as steam in an amount of 0.5 g or more per kg of granular polyethylene terephthalate, or is present so that the granular polyethylene terephthalate and steam are brought into contact with each other.

The contact between the chips of the aromatic polyester (A) and water vapor is usually performed for 10 minutes to 2 days, preferably 20 minutes to 10 hours.

The method of industrially carrying out the contact treatment of the particulate polyethylene terephthalate with steam or a steam-containing gas is shown below, but the method is not limited to this. Further, the treatment method may be either a continuous method or a batch method.

When the chips of the aromatic polyester (A) are subjected to a contact treatment with steam in a batch system, a silo type treatment apparatus can be used. That is, the chips of the aromatic polyester (A) are received in a silo, and steam or a steam-containing gas is supplied in a batch method to perform a contact treatment. Alternatively, the granular polyethylene terephthalate may be received in a rotating tube type contact treatment device, and the contact treatment may be performed while rotating to make the contact more efficient.

When the chips of the aromatic polyester (A) are continuously contacted with steam, granular polyethylene terephthalate is continuously received from the upper part in a tower type processing apparatus, and steam is continuously supplied in a cocurrent or countercurrent to steam. Can be contact treated.

As described above, when treated with water or steam, the granular polyethylene terephthalate is drained by a draining device such as a vibrating screener or Simon Carter, if necessary, and transferred to the next drying step.

For drying the chips of the aromatic polyester (A) which has been subjected to contact treatment with water or steam, a commonly used drying treatment of aromatic polyester can be used. As a method for continuously drying, a hopper-type ventilation dryer in which chips of the aromatic polyester (A) are supplied from the upper part and a dry gas is aerated from the lower part is usually used. As a method of reducing the amount of dry gas and efficiently drying, a rotating disk type continuous dryer is used, and while supplying a small amount of dry gas, heating steam and heating medium are supplied to the rotating disk and the outer jacket. The chips of aromatic polyester (A) can be indirectly heated and dried.

A double-cone type rotary dryer is used as a dryer for batch-type drying, and can be dried under vacuum or under vacuum while a small amount of dry gas is passed through. Alternatively, it may be dried under atmospheric pressure while aerating a dry gas.

As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferable from the viewpoint of preventing a decrease in molecular weight due to hydrolysis or thermal oxidative decomposition of the aromatic polyester (A).

As described above, the aromatic polyester (A)
By subjecting the polyethylene terephthalate to water or steam treatment, it is possible to suppress an increase in oligomers after the polyethylene terephthalate is heated and melted at a temperature of 290 ° C.

When the aromatic polyester (A) is an aromatic polyester having a repeating unit mainly composed of a terephthalic acid component and an ethylene glycol component, the polyester resin composition of the present invention is heated and melted at a temperature of 290 ° C. When the Tc1 of the molded product molded by the above is measured, it is preferable that the Tc1 is 145 to 175 ° C. and the haze is 15% or less. When Tc1 is lower than 145 ° C., the transparency of the molded product becomes extremely poor. Also, when Tc1 is higher than 175 ° C, the transparency of the molded product is very good, but in the case of a bottle, the crystallinity of the spout is low and the content may leak after filling and capping. is there. Further, when a polyester resin composition having a haze of 15% or more is used, the transparency of the bottle becomes very poor.

The polyester resin composition of the present invention can be used to produce a transparent hollow molded article having excellent heat resistance by a known method such as a hot parison method or a cold parison method. It is also preferable to produce a molded product such as a film or a sheet, or a multilayer hollow molded product.

In the polyester resin composition of the present invention, if necessary, known ultraviolet absorbers, lubricants, release agents, nucleating agents,
You may mix | blend various additives, such as a stabilizer, an antistatic agent, and a pigment.

[0091]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
In the examples, "parts" means "parts by weight". Moreover, each measurement item followed the following method.

(1) Acetaldehyde content (AA content) Sample / distilled water = 1 g / 2 cc was placed in a glass ampoule purged with nitrogen, the upper part was sealed and subjected to extraction treatment at 160 ° C. for 2 hours, and after cooling, in the extract Of acetaldehyde was measured by high sensitivity gas chromatography and the concentration was expressed in ppm. ΔW (AA increase amount) during melting of aromatic polyester Put 3 g of dried aromatic polyester chips into a glass test tube, and place in an oil bath at 290 ° C. under a nitrogen atmosphere.
Dip for 0 minutes to melt. ΔW during melting (AA increase)
Is calculated by the following equation. ΔW (increase of AA during melting (ppm)) = [A after melting
A (ppm) -AA amount before melting (ppm)]

(2) Intrinsic viscosity (IV) of aromatic polyester It was determined from the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent.

(3) Content of aromatic trimer cyclic trimer A sample is dissolved in a hexafluoroisopropanol / chloroform mixture, and chloroform is added to dilute the sample. Methanol is added to this to precipitate the polymer, which is then filtered. The filtrate was evaporated to dryness, the volume was made constant with dimethylformamide, and the cyclic trimer composed of ethylene terephthalate units was quantified by liquid chromatography.

(4) Increasing amount of cyclic trimer during melting of aromatic polyester (ΔCT) 3 g of dried aromatic polyester chips were put in a glass test tube and placed in an oil bath at 290 ° C. under a nitrogen atmosphere. 6
Dip for 0 minutes to melt. The amount of cyclic trimer increase during melting is determined by the following formula. Increasing amount of cyclic trimer during melting (% by weight) = [Content of cyclic trimer after melting (% by weight) -Content of cyclic trimer before melting (% by weight)]

(5) Density of aromatic polyester chip 25 with a density gradient tube of carbon tetrachloride / n-heptane mixed solvent
It was measured at ° C.

(6) Haze of bottle (% haze) Samples were cut at four locations from the center of the body of the bottle after molding 5000 times (at a thickness of about 0.4 mm), and haze was measured with a haze meter manufactured by Toyo Seisakusho. The average of four points was calculated.

(7) Bottle haze unevenness After 10 moldings, a sample was cut out at four locations from the center of the body of the bottle (where the wall thickness was about 0.4 mm), and the haze was measured with a haze meter manufactured by Toyo Seisakusho. Maze = Maximum haze / Minimum haze

(8) Unevenness of bottle thickness Samples at 4 points (3 cm x
3 cm) was cut out and its thickness was measured with a digital thickness meter (the same sample was measured at 5 points each and the average was taken as the sample thickness). Thickness unevenness = maximum thickness / minimum thickness

(9) Capping Property 1500 cc of water at 90 ° C. was put in a molded bottle, and a polypropylene resin screw cap equipped with a polypropylene resin inner seal was used. This bottle filled with water is laid down sideways, and at 5 ° C for 10 hours,
Subsequently, a leaving test was carried out at 80 ° C. for 10 hours to check the contents for leakage. The test was conducted with 5 bottles, and the number of bottles in which leakage of the content was recognized was counted.

(10) Evaluation of mold stains (evaluation by unstretched sheet) A polyester resin composition was melt-extruded to obtain an unstretched sheet having a thickness of 0.3 mm, and a mold temperature of 165 ° C. was applied to the mold. Time 1.0 sec, Cycle time 1.2 sec [(Mold pressing 1.0 sec + Mold release 0.
2 seconds) / time], continuous molding was performed, and the number of times of molding until the dirt adhered to the mold was evaluated as the mold dirt.

(Evaluation by Biaxially Stretching Molded Container) The polyester resin composition was dried by a dryer using dehumidified air, and a resin temperature of 290 was measured by an M-100 injection molding machine manufactured by Meiki Seisakusho.
The preform was molded at ° C. After heating and crystallizing the mouthpiece part of this preform with a homemade mouthpiece part crystallization device,
Biaxial stretch blow molding was performed using a LB-01 stretch blow molding machine manufactured by Corpoplast Co., Ltd., followed by heat setting for 10 seconds in a mold set at 155 ° C. to obtain a 500 cc hollow molding container. Stretch blow molding was continuously carried out under the same conditions, and the mold stain was evaluated by the number of moldings until the transparency of the container was impaired by visual observation. As the haze measurement sample, the body of the container after continuous molding for 5,000 times was used.

(12) AA amount in the hollow molded container (pp
m) A sample was cut out from the mouth of the hollow molded container obtained by the above-mentioned biaxial stretching, and used for the measurement. Sample / distilled water =
1 g / 2 cc was placed in a glass ampoule that had been purged with nitrogen, the upper part was sealed and subjected to extraction treatment at 160 ° C. for 2 hours, and after cooling, acetaldehyde in the extract was measured by high sensitivity gas chromatography and the concentration was expressed in ppm. .

(13) Haze of Molded Plate (% Humidity) The haze meter manufactured by Toyo Seiki Seisaku-sho, Ltd. was used using the following molded plate having a thickness of 5 mm.

(14) Molding of Molded Plate A dried polyester resin composition was used as M-1 manufactured by Meiki Seisakusho.
Molding is carried out using a 00 flat plate mold cooled to 10 ° C. at a cylinder temperature of 290 ° C. by an injection molding machine. Stepped flat plate dies are 2, 3, 4, 5, 6, 7, 8, 9, 10,
The plate is provided with a 3 cm × 5 cm square plate having a thickness of 11 mm in a stepwise manner. The measurement is an average value of three molded plates. A plate having a thickness of 5 mm was used for measuring haze (% haze).

Example 1 High-purity terephthalic acid and ethyl glycol were fed to a first esterification reactor containing a reactant in advance, and the mixture was stirred at about 250 ° C. at 0.5 kg /
The reaction was carried out in cm ² G with an average residence time of 3 hours. In addition, crystalline germanium dioxide was heated and dissolved in water, ethylene glycol was added thereto and heat treated, and an ethylene glycol solution of phosphoric acid was separately fed continuously to the first esterification reactor. This reaction product was sent to the second esterification reactor and stirred at about 260 ° C. and 0.05 kg.
The reaction was performed at a predetermined reactivity of / cm ² G. This esterification reaction product is continuously sent to the first polymerization reactor, and is stirred at about 265 ° C. at 25 torr for 1 hour and then to the second polymerization reactor.
With stirring in a polymerization reactor, 2,2 'ethylidene bis (4,6-
Di-tert-butylphenol) (CAS REGISTRY NUM
BER: 35958-30-6) to 1.0 part by weight, charged at about 265 ° C., 3 torr for 1 hour, and further stirred at the third polymerization reactor at about 275 ° C., 0.5 to 1 torr.
Polymerization was carried out at r for 1 hour. The PET resin thus obtained had an intrinsic viscosity (IV) of 0.55 and a DEG content of 1.1 mol%.

This resin was continuously treated in a nitrogen atmosphere for about 15 minutes.
Crystallize at 5 ° C, preheat to about 200 ° C under nitrogen atmosphere, and send to continuous solid-state polymerization reactor for about 20 minutes under nitrogen atmosphere.
Solid state polymerization was carried out at 5 ° C. After the solid phase polymerization, fine particles were removed by continuous treatment in a sieving step and a fine particle removing step.

The PET resin obtained had an intrinsic viscosity of 0.75.
Deciliters / gram, cyclic trimer content 0.28% by weight, AA content 28 ppm, density 1.370 g
/ Cm ³ .

For the water treatment of PET resin chips, the apparatus shown in FIG. 1 was used, and the raw material chip supply port (1) at the upper part of the processing tank,
An overflow outlet (2) located at the upper limit level of the treated water in the treatment tank, an outlet (3) for the mixture of aromatic polyester chips and treated water in the lower portion of the treatment tank, and treated water discharged from this overflow outlet, Fine powder removing device (5) in which the treated water discharged from the treatment tank and the treated water discharged from the discharge item at the bottom of the treatment tank via the draining device (4) are continuous filters with a filter material made of paper of 30 μm (6) to be sent again to the water treatment tank via the water, an inlet (7) for the treated water from which the fine powder has been removed, an adsorption tower (8) for adsorbing acetaldehyde in the treated water to which the fine powder has been removed, and new ions. Approximately 32 in volume with exchange water inlet (9)
A 0 liter tower type processing tank was used.

The treated water was continuously charged into the water treatment tank controlled at a temperature of 95 ° C. at a rate of 50 kg / hour from the supply port (1) at the upper part of the treatment tank, and the treated water having a fine powder content of about 130 ppm was used for the water treatment time. After 4 hours, PET chips were continuously extracted together with the treated water from the outlet (3) at the bottom of the treatment tank at a rate of 50 kg / hour. The ΔW (AA increase amount) of the obtained PET during melting was 31 ppm, and the cyclic trimer increase amount (ΔCT) was 0.20 wt%.

100 parts by weight of this PET resin and a metaxylylene group-containing polyamide resin (T-6 manufactured by Toyobo Co., Ltd.)
00) 2.0 parts by weight were dry-blended, and then the above evaluation was carried out on the melt-formed unstretched sheet and the biaxially stretch-molded bottle. The results are shown in Table 1. As is clear from Table 1, the amount of AA in the molded bottle was as low as 22 ppm, and 1
After 5000 sheets or more of sheet molding and bottle molding, virtually no mold stain was observed, the transparency (haze) of the bottle was good, and there was no problem with haze unevenness or thickness unevenness. Further, this bottle was filled with 90 ° C. hot water, capped with a capping machine, and then the bottle was laid down and left to stand, and the deformation of the spout and the leakage of the contents were examined, but there was no problem.

Thereafter, the composition shown in Table 1 was similarly used.
The polyester resin compositions of Examples 2 to 5 were evaluated using an unstretched sheet and a biaxially stretched molded bottle.

Comparative Example 1 A slurry of high-purity terephthalic acid and ethyl glycol was continuously supplied to a first esterification reactor containing a reactant in advance, and the slurry was stirred at about 25
The reaction was carried out at 0 ° C. and 0.5 kg / cm ² G for an average residence time of 3 hours. In addition, crystalline germanium dioxide was heated and dissolved in water, ethylene glycol was added thereto and heat treated, and an ethylene glycol solution of phosphoric acid was separately fed continuously to the first esterification reactor. The reaction mass is sent to the second esterification reactor and stirred for about 26
The reaction was carried out at 0 ° C. and 0.05 kg / cm ² G to a predetermined degree of reactivity. The esterification reaction product is continuously sent to the first polymerization reactor, and is stirred at about 265 ° C. at 25 torr for 1 hour, and then is stirred at the second polymerization reactor at about 265 ° C.
At 3 torr for 1 hour, with stirring in the third polymerization reactor,
Polymerization was carried out at about 275 ° C. and 0.5 to 1 torr for 1 hour.
The obtained PET resin has an intrinsic viscosity (IV) of 0.53, D
The EG content was 2.7 mol%.

P subjected to the solid-state polymerization treatment in the same manner as in Example 1
The ET resin was immersed in distilled water in a glass container, heated from the outside, treated at an internal temperature of about 95 ° C. for 4 hours, and then dried.
100 parts by weight of this PET resin and a metaxylylene group-containing polyamide resin (T-600, manufactured by Toyobo Co., Ltd.) 0.5
After dry blending parts by weight, the above evaluation was performed on the melt-formed unstretched sheet and the biaxially stretch-molded bottle. The results are shown in Table-1. As is clear from Table 1, Δ in the obtained aromatic polyester resin composition when melted
The W (AA increase amount) was 88 ppm, and the cyclic trimer increase amount was 0.20% by weight. Further, the amount of AA in the molded bottle was as high as 28 ppm.

[0115]

[Table 1]

*) Hindered phenolic compound 1) 2,2'-ethylidene bis (4,6-di-tert)
-Butylphenol) (CAS REGISTRY NUMBER: 3595)
8-30-6) Molecular weight 438 2) 2,2'-ethylidene bis (4,6-di-n-heptamethylenephenol) molecular weight 540 3) 2,2'-ethylidene bis (4,6-di-isopropylene) Phenol) molecular weight 382 4) 2,2'-butylidene bis (4,6-di-tert)
-Butylphenol) molecular weight 566 6) Metaxylylene group-containing polyamide: Toyobo Co., Ltd.
Made T-600

[0117]

The present invention is directed to an aromatic polyester (A) having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, a hindered phenolic compound (B) represented by the formula (1) and a metaxylylene group. A polyester composition comprising the contained polyamide (C), wherein the content of acetaldehyde is 40 ppm or less, 29
Increase in acetaldehyde when melting at 0 ° C is 50pp
A polyester resin composition having a thickness of m or less and being excellent in transparency, heat resistance, and long-term moldability is provided, and can meet high quality requirements in the fields of containers, sheets and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F071 AA45 AA46 AA54 AA55 AC11                       AE05 AH05 BA01 BB05 BB06                       BC04                 4J002 CF051 CF061 CF071 CL002                       CL032 EJ066 FD066 GG01

Claims (5)

[Claims] 1. An aromatic polyester (A) having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, and a hindered phenol compound (B) represented by the general formula (1). And a polyester resin composition. [Chemical 1] (R10, R11, R12, R13, R1 in the formula (1)
4 may be the same or different and represents alkyl and / or phenyl and / or cycloalkyl having 1 to 30 carbon atoms. ) 2. The polyester resin composition according to claim 1, further comprising a metaxylylene group-containing polyamide resin (C). 3. A polyester resin composition, which is formed into chips after polymerization and is treated with treated water satisfying the following conditions (a) and (b) in a treatment tank. The polyester resin composition according to claim 1 or 2. (A) Temperature 40 to 120 ° C. (b) Treated water including wastewater from the treatment tank 4. A polyester resin composition at 6 ° C. at 290 ° C.
Acetaldehyde content when melted for 0 minutes is W1pp
ΔW = W1−W0 and ΔW is 5 when the acetaldehyde content without melting treatment at 290 ° C. for 60 minutes is W0 ppm.
It is 0 ppm or less, Claim 1, 2 or 3 characterized by the above-mentioned.
The polyester resin composition described. 5. A hollow molded article comprising the polyester resin composition according to any one of claims 1 to 4.