JP2005344123A - Polyester composition and polyester packaging material comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition excellent in transparency, thermal stability, and flavor retention or excellent in transparency, thermal stability, flavor retention and gas barrier properties, and hardly causing mold stain at molding; and to provide a polyester packaging material comprising the polyester composition. <P>SOLUTION: The polyester composition comprises 100 pts.wt. thermoplastic polyester and 0.1-50 pts.wt. partially aromatic polyamide, and preferably contains an alkali metal atom in an amount of 0.1 to 300 ppm. Further, it is preferable that the ratio of a terminal amino group concentration to a terminal carboxy group concentration in the partially aromatic polyamide is 1.0 to 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention is excellent in transparency, heat stability and flavor retention properties of a polyester composition suitably used as a raw material of a molded body such as a hollow molded container including a beverage bottle, a film and a sheet, The present invention also relates to a polyester packaging material excellent in gas barrier properties.

Thermoplastic polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as PET) have excellent mechanical and chemical properties, and thus have a high industrial value, such as fibers, films and sheets. Widely used as bottles, etc. Furthermore, since thermoplastic polyester is excellent in heat resistance, transparency, and gas barrier properties, it is particularly suitable as a material for packaging materials such as containers for filling beverages such as juices, soft drinks, and carbonated drinks.

For example, such a thermoplastic polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape and subjected to stretch blow molding. Generally, the body portion of the rear bottle is heat-treated (heat set) to be formed into a hollow molded container, and further, the cap portion of the bottle is heat-treated (crystallization of the plug portion) as necessary.

However, PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. In addition, PET produced acetaldehyde by thermal decomposition when thermoforming a molded body such as a hollow molded body, and the acetaldehyde content in the material of the obtained molded body was increased, and the hollow molded body was filled. Affects the flavor and odor of beverages.

In order to solve such a problem, various measures have heretofore been taken in order to reduce the acetaldehyde content in the thermoplastic polyester molded body. In general, a method using a thermoplastic polyester in which the AA content is reduced by solid-phase polymerization of a melt-polycondensed prepolymer, and AA generation at the time of molding using a copolymer thermoplastic polyester having a lower melting point A method for lowering the temperature, a method for reducing the molding temperature during thermoforming as much as possible, a method for reducing the shear stress during thermoforming as much as possible, and the like are known.

In recent years, thermoplastic polyester containers mainly made of polyethylene terephthalate have come to be used as containers for low flavor beverages such as mineral water and oolong tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but these containers can be obtained only by reducing the AA content in the thermoplastic polyester molded material by the above method. It has been found that the flavor and odor of the contents are not improved, and there is a need for improvement.

As a technique for solving such a problem, a method 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 thermoplastic polyester resin (Patent Literature). 1) and a polyester container (see Patent Document 2) made of a polyester composition containing a thermoplastic polyester and a specific polyamide whose terminal amino group concentration is regulated within a certain range has been proposed. It has also been found that a container for a low-flavor beverage such as a beverage may be insufficient in terms of the flavor and smell of the beverage.
Japanese Examined Patent Publication No. 6-6661 Japanese Examined Patent Publication No. 4-71425

On the other hand, a thermoplastic polyester packaging material mainly composed of PET is excellent in gas barrier properties as described above, but a hollow molded body for contents containing a compound very sensitive to oxygen such as vitamin C. As a result, it has been found to be unsatisfactory, and improvements are required.

As a technique for solving such problems, we have made a thermoplastic polyester hollow molded body containing 1 to 100 parts by weight of a metaxylylene group-containing polyamide resin with respect to 100 parts by weight of the thermoplastic polyester resin (see Patent Document 3). Proposed. However, it has been found that the flavor and odor of beverages, particularly low flavor beverages, filled in hollow molded articles made of such polyester compositions are problematic.
Japanese Examined Patent Publication No. 4-54702

Further, when the heat-resistant hollow molded body is produced using the polyester composition, the body of the hollow molded body is heat-treated. During the heat treatment, the inner surface of the mold, the gas exhaust port of the mold, the exhaust There is a problem that mold stains in which foreign matter adheres to the tube are much more likely to occur than when molding using only a thermoplastic polyester resin. This is also unresolved, and improvement is required.

Further, it has been studied to laminate a thermoplastic polyester film having good heat resistance on a metal plate, and to use the laminated metal plate mainly for metal cans for foodstuff containers such as soft drinks, beer and canned foods. In such applications, in order to improve flavor retention, a thermoplastic polyester film for metal sheet lamination (see Patent Document 4) having an acetaldehyde content of 20 ppm or less has been proposed. However, it turns out that it does not completely solve the problem, and improvement is required.
Japanese Patent Laid-Open No. 5-339393

The present invention is to solve the above-mentioned problems of the prior art, and is excellent in transparency, thermal stability and flavor retention, or transparency, thermal stability, flavor retention and gas barrier property, and further molding. It is an object of the present invention to provide a polyester composition that hardly causes mold stains and a polyester packaging material made thereof.

The present inventors have used a polyester composition comprising 100 parts by weight of a thermoplastic polyester and 0.1 to 50 parts by weight of a partially aromatic polyamide, and transparency and flavor retention, or transparency, flavor retention and As a result of examining the polyester packaging material excellent in gas barrier properties and its production, the alkali metal atom content in the polyester composition or the alkali metal atom content in the polyester packaging material is related to transparency and flavor retention. As a result, the present invention was completed.

That is, the polyester composition of the present invention is a polyester composition comprising 100 parts by weight of a thermoplastic polyester and 0.1 to 50 parts by weight of a partially aromatic polyamide, and the content of alkali metal atoms in the polyester composition is It is within the range of 0.1 to 300 ppm, and the ratio of the terminal amino group concentration to the terminal carboxyl group concentration in the partially aromatic polyamide is 1.0 to 20.

The lower limit of the alkali metal atom content in the polyester composition is preferably 1 ppm, more preferably 5 ppm. The upper limit of the alkali metal atom content in the polyester composition is preferably 270 ppm, more preferably 250 ppm.

When the content of the alkali metal atom in the polyester composition is less than 0.1 ppm, the polyester composition is used for producing a polyester packaging material, and the coloring becomes intense or the gelation easily proceeds. As a result, burnt streaks and unmelted materials are easily generated. On the other hand, when the content of alkali metal atoms in the polyester composition is more than 300 ppm, the generation of burnt lines and unmelted materials is almost eliminated, but the transparency and flavor retention of the resulting polyester packaging material are deteriorated, Decrease in molecular weight occurs and mechanical strength decreases.

As a method of bringing the alkali metal atom content in the polyester composition within the range of 0.1 to 300 ppm, the alkali metal content contained in the partially aromatic polyamide is adjusted according to the amount of the partially aromatic polyamide used, A method such as adjusting the amount of alkali metal contained in the polyester can be used.

The alkali metal atom content in the partially aromatic polyamide used in the present invention is atomic absorption analysis, emission analysis, inductively coupled plasma (hereinafter abbreviated as ICP) emission analysis, ICP mass spectrometry, fluorescent X-ray. It is calculated | required by the analysis method etc., and can be used properly by alkali metal atom concentration.

In this case, the thermoplastic polyester is preferably a polyester having ethylene terephthalate as a main repeating unit.

In this case, the partially aromatic polyamide is preferably a polyamide containing 20 mol% or more of structural units derived from metaxylylenediamine and dicarboxylic acid in the molecular chain.

In this case, it is preferable that the secondary transition point of the partially aromatic polyamide measured by DSC (differential scanning calorimeter) is 50 to 120 ° C.

In this case, the acetaldehyde content (A _t ) (ppm) of the molded product obtained by injection molding of the polyester composition, and the acetaldehyde content (A ₀ ) (ppm) of the polyester composition before injection molding, The difference (A _t −A ₀ ) is preferably 20 ppm or less.

Here, the acetaldehyde content (A _t ) of the molded product obtained by injection molding the polyester composition is M-150C (DM) manufactured by Meiki Seisakusho, which is a polyester composition dried at 100 ° C. under a nitrogen stream. From a 2 mm thick plate of stepped molding plate obtained by injection molding using a stepped flat plate mold (surface temperature of about 22 ° C) cooled with 10 ° C water at an injection molding machine at a cylinder temperature of 290 ° C. The acetaldehyde content of the collected resin is meant, and the acetaldehyde content (A ₀ ) of the polyester composition before injection molding means the acetaldehyde content of the dried polyester composition before injection molding. Then, the difference (A _t −A ₀ ) is obtained by the following equation as described in the section of measurement method (5) below.

Difference in acetaldehyde content before and after injection molding (A _t -A ₀ ) (ppm)
= Acetaldehyde content (A _t ) (ppm) of stepped molded plate after injection molding
- before injection molding dry acetaldehyde content of the polyester composition (A ₀₎ (ppm)

The polyester packaging material of the present invention is formed by molding the above polyester composition.
In this case, the alkali metal atom content in the polyester packaging material is preferably in the range of 0.1 to 300 ppm.
In this case, the acetaldehyde content in the polyester packaging material is preferably 20 ppm or less.

In this case, when the polyester packaging material was melt-treated at 290 ° C. for 30 minutes, the increased amount of acetaldehyde content (ΔAA) (ppm) and the increased amount of cyclic ester trimer derived from thermoplastic polyester (ΔCT ₂ ) It is preferable that (wt%) is 20 ppm or less and 0.40 wt% or less, respectively.

Here, when the polyester packaging material was melt-treated at 290 ° C. for 30 minutes, the increase amount of acetaldehyde content (ΔAA) (ppm) and the increase amount of cyclic ester trimer derived from thermoplastic polyester (ΔCT ₂ ) (% By weight) is obtained by the following equation as described in the following measurement methods (6) and (7).
Increase amount of acetaldehyde content during melt processing (ΔAA) (ppm) =
Acetaldehyde content after melt treatment (ppm)-Acetaldehyde content after drying before melt treatment (ppm)

Increase amount of cyclic ester trimer during melt treatment (ΔCT ₂ ) (% by weight) =
Cyclic ester trimer content after melt treatment (wt%)-cyclic ester trimer content before melt processing (wt%)

In this case, the content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material is preferably 0.70% by weight or less.

In this case, the content of the metaxylylene group-containing cyclic amide monomer in the polyester packaging material is preferably 0.3% by weight or less.
The polyester packaging material of the present invention can be any one of a hollow molded body, a sheet-like material, or a stretched film obtained by stretching the sheet-like material in at least one direction.

According to the polyester composition of the present invention, a polyester packaging material excellent in transparency, heat stability and flavor retention, or transparency, heat stability, flavor retention and gas barrier property can be obtained. As described above, the polyester packaging material is very suitable as a packaging material for beverages such as soft drinks.

Hereinafter, embodiments of the polyester composition of the present invention and the polyester packaging material comprising the same will be specifically described.
The thermoplastic polyester used in the present invention is a crystalline thermoplastic polyester obtained mainly from an aromatic dicarboxylic acid component and a glycol component, and more preferably, the aromatic dicarboxylic acid unit is 85 mol% or more of the acid component. The thermoplastic polyester is particularly preferably 90 mol% or more, and most preferably a thermoplastic polyester containing aromatic dicarboxylic acid units of 95 mol% or more of the acid component.

Examples of the aromatic dicarboxylic acid component constituting the thermoplastic polyester used in the present invention include fragrances such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. Group dicarboxylic acids and functional derivatives thereof.

Examples of the glycol component constituting the thermoplastic polyester used in the present invention include alicyclic groups such as ethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, and cyclohexanedimethanol. Examples include glycol.
Examples of the acid component used as a copolymerization component in the thermoplastic polyester include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. Aromatic dicarboxylic acids, oxyacids such as p-oxybenzoic acid and oxycaproic acid and their functional derivatives, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, glutaric acid and dimer acid, and their functional Derivatives, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, and cyclohexanedicarboxylic acid, and functional derivatives thereof.

Examples of the glycol component used as a copolymerization component in the thermoplastic polyester include ethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, diethylene glycol, neopentyl glycol. Aliphatic glycols such as cyclohexane dimethanol, etc., 1,3-bis (2-hydroxyethoxy) benzene, bisphenol A, alkylene oxide adducts of bisphenol A, etc. And polyalkylene glycols such as aromatic glycol, polyethylene glycol and polybutylene glycol.

Furthermore, polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, glycerin, pentaerythritol, trimethylolpropane, etc. are used within the range in which the thermoplastic polyester is substantially linear. It may be polymerized or a monofunctional compound such as benzoic acid or naphthoic acid may be copolymerized.

The thermoplastic polyester according to the present invention is preferably a polyester containing 70 mol% or more of a structural unit derived from an aromatic dicarboxylic acid and at least one glycol selected from aliphatic glycols having 2 to 4 carbon atoms.

A preferred example of the thermoplastic polyester used in the present invention is a thermoplastic polyester whose main repeating unit is composed of ethylene terephthalate, and more preferably contains 85 mol% or more of ethylene terephthalate units, It is a linear copolymer thermoplastic polyester containing isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedimethanol and the like as a component, and particularly preferably a line containing 95 mol% or more of ethylene terephthalate units. It is a thermoplastic polyester.

Examples of these linear thermoplastic polyesters include polyethylene terephthalate (hereinafter abbreviated as PET), poly (ethylene terephthalate-ethylene isophthalate) copolymer, poly (ethylene terephthalate-ethylene isophthalate-ethylene-2,6-naphthalate). ) Copolymer, poly (ethylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly (ethylene terephthalate-ethylene-2,6-naphthalate) copolymer, poly (ethylene terephthalate-dioxyethylene terephthalate) Examples thereof include a copolymer, a poly (ethylene terephthalate-1,3-propylene terephthalate) copolymer, and a poly (ethylene terephthalate-ethylenecyclohexylene dicarboxylate) copolymer.

Another preferred example of the thermoplastic polyester used in the present invention is a thermoplastic polyester whose main repeating unit is composed of ethylene-2,6-naphthalate, more preferably ethylene-2,6-naphthalate. It is a linear thermoplastic polyester containing 85 mol% or more of a vinyl unit, and a linear thermoplastic polyester containing 95 mol% or more of an ethylene-2,6-naphthalate unit is particularly preferable.

Examples of these linear thermoplastic polyesters include polyethylene-2,6-naphthalate, poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, poly (ethylene-2,6-naphthalate-ethylene isophthalate). Examples thereof include a copolymer and a poly (ethylene-2,6-naphthalate-dioxyethylene-2,6-naphthalate) copolymer.

Further, other preferable examples of the thermoplastic polyester according to the present invention are thermoplastic polyesters whose main structural unit is composed of 1,3-propylene terephthalate, and more preferably 1,3-propylene terephthalate. A linear thermoplastic polyester containing 70 mol% or more of a vinyl unit, and particularly preferred is a linear thermoplastic polyester containing 90 mol% or more of a 1,3-propylene terephthalate unit.

Examples of these linear thermoplastic polyesters include polypropylene terephthalate (PTT), poly (1,3-propylene terephthalate-1,3-propylene isophthalate) copolymer, poly (1,3-propylene terephthalate-1,4). -Cyclohexane dimethylene terephthalate) copolymer, poly (1,3-propylene terephthalate-1,3-propylene-2,6-naphthalate) copolymer, and the like.

Furthermore, other preferable examples of the thermoplastic polyester according to the present invention are thermoplastic polyesters in which the main structural unit is composed of butylene terephthalate, and more preferably 70 mol% or more of butylene terephthalate units. The linear copolymerized thermoplastic polyester is particularly preferably a linear thermoplastic polyester containing 90 mol% or more of butylene terephthalate units.

Examples of these linear thermoplastic polyesters include polyethylene terephthalate (PBT), poly (butylene terephthalate-butylene isophthalate) copolymer, poly (brene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly (Brene terephthalate-butylene-2,6-naphthalate) copolymer, poly (butylene terephthalate-1,3-propylene terephthalate) copolymer, poly (butylene terephthalate-butylene cyclohexylene dicarboxylate) copolymer, and the like. It is done.

Other preferable examples of the thermoplastic polyester according to the present invention other than the above are thermoplastic polyesters in which the main structural unit is composed of 1,3-propylene-ethylene-2,6-naphthalate and the main structural unit is in butylene. -Thermoplastic polyester composed of ethylene-2,6-naphthalate.

The thermoplastic polyester can be produced by a conventionally known production method. That is, in the case of PET, terephthalic acid, ethylene glycol and, if necessary, the above copolymerization component are directly reacted to distill off water and esterify, and then, as a polycondensation catalyst, Sb compound, Ge compound, Ti A direct esterification method in which polycondensation is performed under reduced pressure using one or more compounds selected from a compound or an Al compound, or dimethyl terephthalate and ethylene glycol and, if necessary, the above copolymerization component as a transesterification catalyst After the methyl alcohol is distilled off and subjected to transesterification, one or more compounds selected from Sb compounds, Ge compounds, Ti compounds or Al compounds are used as a polycondensation catalyst. It is produced mainly by a transesterification method in which polycondensation is performed under reduced pressure.
Furthermore, in order to increase the intrinsic viscosity of the thermoplastic polyester and reduce the acetaldehyde content and the cyclic ester trimer content, solid phase polymerization may be performed.

The esterification reaction, transesterification reaction, melt polycondensation reaction and solid phase polymerization reaction may be performed in a batch reactor or a continuous reactor. In any of these methods, the melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. 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. Melt polycondensation and solid phase polymerization may be carried out continuously or separately.

The glycols such as aromatic dicarboxylic acid dimethyl ester, aromatic dicarboxylic acid or ethylene glycol which are the above starting materials include virgin dimethyl terephthalate derived from paraxylene, ethylene glycol derived from terephthalic acid or ethylene, of course. In addition, recovered raw materials such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered from used PET bottles by chemical recycling methods such as methanol decomposition and ethylene glycol decomposition are also used as at least part of the starting material. I can do it. Needless to say, the quality of the recovered raw material must be refined to a purity and quality suitable for the intended use.

Examples of the Sb compound used in the production of the thermoplastic polyester used in the present invention include antimony trioxide, antimony acetate, antimony tartrate, antimony tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. Etc. The Sb compound is added so that the residual amount of Sb in the produced polymer is in the range of 50 to 250 ppm.

Examples of the Ge compound used in the production of the thermoplastic polyester used in the present invention include amorphous germanium dioxide, crystalline germanium dioxide, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, germanium phosphite and the like. Can be mentioned. When a Ge compound is used, the amount used is 5 to 150 ppm, preferably 10 to 100 ppm, more preferably 15 to 70 ppm as the residual amount of Ge in the thermoplastic polyester.

Examples of the Ti compound used for the production of the thermoplastic polyester used in the present invention include tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetra-n-butyl titanate and the like. Alkyl titanates and their partial hydrolysates, titanium acetate, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, titanyl calcium oxalate, titanium strontium oxalate, titanium trimellitate, sulfuric Titanium, titanium chloride, hydrolyzate of titanium halide, titanium oxalate, titanium fluoride, potassium hexafluorotitanate, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium Such as acetylacetonate It is below. The Ti compound is added so that the residual amount of Ti in the produced polymer is in the range of 0.1 to 10 ppm.

In addition, specific examples of the Al compound used in the production of the thermoplastic polyester used in the present invention include aluminum formate, aluminum acetate, basic aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, and lauric acid. Carboxylates such as aluminum, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate, aluminum citrate, aluminum salicylate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, polyaluminum chloride, aluminum nitrate, aluminum sulfate , Inorganic acid salts such as aluminum carbonate, aluminum phosphate, aluminum phosphonate, aluminum methoxide, aluminum ethoxide, aluminum n Aluminum chelate compounds such as propoxide, aluminum iso-propoxide, aluminum n-butoxide, aluminum t-butoxide, etc. aluminum alkoxide, aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, Examples include organoaluminum compounds such as trimethylaluminum and triethylaluminum, partial hydrolysates thereof, and aluminum oxide. Of these, carboxylates, inorganic acid salts and chelate compounds are preferred, and among these, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, polyaluminum chloride and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the Al remaining amount in the produced polymer is in the range of 5 to 200 ppm.

These catalyst compounds can be used, for example, as an ethylene glycol solution at any stage from the end of the transesterification process or from the end of the transesterification reaction to the start of the polycondensation reaction, It can be added at any stage.

In the production of the thermoplastic polyester used in the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination. Examples of the alkali metal compound or alkaline earth metal compound include carboxylates such as acetates of these elements, alkoxides, and the like, and are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, and the like. The alkali metal compound or alkaline earth metal compound is added so that the residual amount of these elements in the produced polymer is in the range of 1 to 50 ppm.
The catalyst compound can be added at any stage of the thermoplastic polyester production reaction step.

Moreover, various phosphorus compounds can be used as a stabilizer. Examples of the phosphorus compound used in the present invention include phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, phosphorous acid trimethyl ester, phosphorous acid triethyl ester, phosphorous acid tributyl ester, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenyl -Luphosphonic acid diphenyl ester, etc., and these may be used alone or in combination of two or more. The phosphorus compound is added at any stage of the thermoplastic polyester formation reaction step so that the amount of phosphorus remaining in the produced polymer is in the range of 5 to 100 ppm.

In the production of the thermoplastic polyester according to the present invention, it is preferable to use a basic nitrogen compound in order to suppress the production of dialkylene glycol by-produced from glycol. As the basic nitrogen compound, any of aliphatic, alicyclic, aromatic and heterocyclic nitrogen compounds may be used. Specific examples include triethylamine, tributylamine, dimethylaniline, dimethylaniline, pyridine, quinoline, dimethylbenzylamine, piperidine, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, triethylbenzylammonium hydroxide, imidazole, imidazoline, and the like. . These compounds may be used in free form or as a salt of lower fatty acid or TPA. The addition of these basic nitrogen compounds to the reaction system can be appropriately selected at any stage until the initial polycondensation reaction is completed, and may be used alone or in combination of two or more. Good.

The compounding amount of these basic nitrogen compounds is 0.01 to 1 mol%, preferably 0.05 to 0.7 mol%, more preferably 0.1 to 0.5 mol% per polyester. When the blending amount of the basic nitrogen compound is less than 0.01 mol%, the transparency of the obtained hollow molded body from the polyester, particularly the stretched heat-fixed hollow molded body, becomes very poor. Moreover, when it exceeds 1 mol%, the color tone of polyester will worsen.

In addition, in order to suppress the viscosity reduction at the time of melting of the polyester composition of the present invention, or to suppress the low molecular weight by-product generated by thermal decomposition of acetaldehyde or allylaldehyde having a strong irritating odor during drying and heat treatment before molding It is also preferable to add a hindered phenolic antioxidant. As such a hindered phenol-based antioxidant, a known one may be used. For example, pentaerythritol-tetra extract [3- (3,5-di-tert-butyl-4-hydride 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5- Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5) -Methyl 3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [ , 5] undecane, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3- (3-tert-butyl-5-methyl) -4-hydroxy 3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,3- (3,5-di-tert- Butyl-4-hydroxyphenyl) bropionate], 2,2-thio-diethylene-bis [3- (3,5-di-tert-butyl-4-hydroxyph-3- (3,5-di-tert-butyl-) 4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] Among them, pentaerythritol-tetra extract [3- (3,5-di-tert-butyl-4-hy [3- (3,5-di-tert-butyl-4-hydroxyph-3- (3,5- Di-tert-butyl-4-hydroxyphenyl) propionate), etc. In this case, the hindered phenolic oxidation stabilizer may be bonded to a thermoplastic polyester, and the polyester composition of the hindered phenolic oxidation stabilizer. The amount in the product is preferably 1% by weight or less based on the weight of the polyester composition, which may be colored when it exceeds 1% by weight, and melt stable even when added in an amount of 1% by weight or more. This is because the ability to improve the properties is saturated, preferably 0.02 to 0.5% by weight.

The intrinsic viscosity of the thermoplastic polyester used in the present invention, particularly the thermoplastic polyester whose main repeating unit is composed of ethylene terephthalate, is preferably 0.55 to 1.50 deciliter / gram, more preferably 0.00. It is in the range of 58 to 1.30 deciliter / gram, more preferably 0.60 to 0.90 deciliter / gram. When the intrinsic viscosity is less than 0.55 deciliter / gram, the mechanical properties of the obtained packaging material and the like are poor. On the other hand, if it exceeds 1.50 deciliters / gram, the resin temperature becomes high when melted by a molding machine or the like, resulting in severe thermal decomposition, increasing the amount of free low molecular weight compounds that affect the flavor retention, Problems such as yellow coloring occur.

The intrinsic viscosity of the thermoplastic polyester used in the present invention, particularly the thermoplastic polyester whose main repeating unit is composed of ethylene-2,6-naphthalate, is 0.40 to 1.00 deciliter / gram, preferably 0. .42 to 0.95 deciliter / gram, more preferably 0.45 to 0.90 deciliter / gram. When the intrinsic viscosity is less than 0.40 deciliter / gram, the mechanical properties of the obtained packaging material and the like are poor. In addition, if it exceeds 1.00 deciliter / gram, the resin temperature becomes high when melted by a molding machine or the like, resulting in severe thermal decomposition, increasing the amount of free low molecular weight compounds that affect the flavor retention, and packaging materials. Problems such as yellowing occur.

The intrinsic viscosity of the thermoplastic polyester according to the present invention, particularly the thermoplastic polyester whose main structural unit is composed of 1,3-propylene terephthalate, is 0.50 to 2.00 deciliter / gram, preferably 0.8. It is in the range of 55 to 1.50 deciliter / gram, more preferably 0.60 to 1.00 deciliter / gram. When the intrinsic viscosity is less than 0.50 deciliter / gram, the mechanical properties of the obtained packaging material and the like are deteriorated, which is a problem. The upper limit of the intrinsic viscosity is 2.00 deciliters / gram. If the upper limit is exceeded, the resin temperature becomes high at the time of melting by a molding machine or the like, resulting in severe thermal decomposition, drastic decrease in molecular weight, and yellowing. Problems such as coloring occur.

Further, the content of dialkylene glycol copolymerized in the thermoplastic polyester according to the present invention is preferably 0.5 to 5.0 mol%, more preferably 1. mol% of the glycol component constituting the thermoplastic polyester. It is 0-4.0 mol%, More preferably, it is 1.5-3.0 mol%. When the amount of dialkylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in the content of aldehydes is unfavorable. In order to produce a thermoplastic polyester having a dialkylene glycol content of less than 0.5 mol%, it is necessary to select uneconomic production conditions as transesterification conditions, esterification conditions or polymerization conditions, Cost does not match. Here, the dialkylene glycol copolymerized in the thermoplastic polyester, for example, in the case of a polyester whose main structural unit is ethylene terephthalate, is a diethylene glycol produced as a by-product during production from ethylene glycol, which is glycol. Among them, diethylene glycol (hereinafter abbreviated as DEG) copolymerized with the thermoplastic polyester, and in the case of a polyester having 1,3-propylene terephthalate as a main structural unit, Di (1,3-propylene glycol) (or bis (3-hydroxypropyl) ether) by-produced from 1,3-propylene glycol, which is a glycol, as a by-product during the production, is a copolymer copolymerized with the thermoplastic polyester. (1,3-propylene glycol (hereinafter referred to as DPG)). .

The content of aldehydes such as acetaldehyde in the thermoplastic polyester according to the present invention is 50 ppm or less, preferably 30 ppm or less, more preferably 10 ppm or less. In particular, when the polyester composition of the present invention is used as a material for containers for low flavor beverages such as mineral water, the content of aldehydes in the thermoplastic polyester is 8 ppm or less, preferably 5 ppm or less, more preferably. Is desirably 4 ppm or less. When the aldehyde content exceeds 50 ppm, the effect of flavor retention of contents such as a molded article molded from this thermoplastic polyester is deteriorated. Further, these lower limits are preferably 0.1 ppb from the viewpoint of production. Here, the aldehydes are acetaldehyde when the thermoplastic polyester is a polyester having ethylene terephthalate as the main constituent unit, and in the case of polyester having 1,3-propylene terephthalate as the main constituent unit. Allyl aldehyde.

Further, the content of the cyclic ester oligomer of the thermoplastic polyester according to the present invention is 70% or less, preferably 60% or less, more preferably 70% or less of the content of the cyclic ester oligomer contained in the melt polycondensate of the thermoplastic polyester. It is preferably 50% or less, particularly preferably 35% or less.
Here, the thermoplastic polyester generally contains cyclic ester oligomers having various degrees of polymerization, but the cyclic ester oligomer referred to in the present invention is the most contained among the cyclic ester oligomers contained in the thermoplastic polyester. It means a cyclic ester oligomer having a high amount, for example, a cyclic trimer in the case of a polyester having ethylene terephthalate as a main repeating unit.
In the case of PET, which is a representative polyester whose main constituent unit is ethylene terephthalate, the thermoplastic polyester has a cyclic trimer content of the melt polycondensed polyester of about 1.0% by weight. The content of the cyclic trimer of the thermoplastic polyester according to the invention is 0.70% by weight or less, preferably 0.60% by weight or less, more preferably 0.50% by weight or less, particularly preferably 0.35% by weight. The following is preferable.

Such a polyester having a reduced content of cyclic ester oligomer can be obtained by a method such as solid-phase polymerization of a melt polycondensed polyester or a heat treatment under an inert gas at a temperature below the melting point.

Further, it is desirable that the increase amount of the cyclic ester oligomer when the thermoplastic polyester according to the present invention is melted at 290 ° C. for 60 minutes is 0.50% by weight or less. The increase amount of the cyclic ester oligomer is preferably 0.40% by weight or less, more preferably 0.30% by weight or less, further preferably 0.20% by weight or less, and particularly preferably 0.10% by weight or less. .
If the content of the cyclic ester oligomer exceeds 0.70% by weight or the increase amount exceeds 0.50% by weight, the cyclic ester oligomer increases when the resin for molding is melted, and the oligomer on the surface of the heating mold is increased. -Adhesion increases rapidly, and the transparency of the obtained hollow molded article etc. is greatly deteriorated. In the case of a film, the oligomer is in the vicinity of the exit of the die or the surface of the drawing roll at the time of film formation or drawing. Adhering and accumulating inside the heat-fixing chamber may cause a problem that they adhere to the film surface and become foreign matter. Moreover, these lower limits are preferably 0.1% by weight and 0.05% by weight, respectively, due to problems in production and production costs.

The thermoplastic polyester according to the present invention in which the cyclic ester oligomer increase amount is 0.50% by weight or less is produced by deactivating a polyester polycondensation catalyst obtained after melt polycondensation or after solid-phase polymerization. be able to.

Examples of the method for deactivating the polyester polycondensation catalyst include a method in which the polyester chip is contacted with water, water vapor or water vapor-containing gas after melt polycondensation or after solid phase polymerization. Examples of the hot water treatment method include a method in which a polyester chip is immersed in water at 20 to 180 ° C. for about 5 minutes to 2 days, a method in which water is applied to the chip with a shower, and the like. Moreover, the method of making a polyester chip | tip and 50-150 degreeC water vapor | steam or water vapor-containing gas contact for 10 minutes-2 days is mentioned.

Another method for deactivating the polycondensation catalyst is to inactivate the polymerization catalyst by adding and mixing the phosphorus compound to the melt of the polyester after melt polycondensation or solid phase polymerization.
In the case of melt polycondensation polyester, the polyester after the melt polycondensation reaction and the polyester resin blended with the phosphorus compound are mixed in an apparatus such as a line mixer that can be mixed in a melted state to inactivate the polycondensation catalyst. The method of making it.
In addition, as a method of blending the phosphorus compound with the solid phase polymerized polyester, a method of dry blending the phosphorus compound with the solid phase polymerized polyester, a polyester master batch chip in which the phosphorus compound is melt kneaded and mixed with the solid phase polymerized polyester chip are mixed. And a method of inactivating a polycondensation catalyst by blending a predetermined amount of a phosphorus compound with polyester and melting it in an extruder or molding machine.
Examples of the phosphorus compound used include the above-described phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof that can be used as a stabilizer during the production of the thermoplastic polyester according to the present invention. These may be used alone or in combination of two or more.

The shape of the thermoplastic polyester chip used in the present invention may be any of a cylinder shape, a square shape, a spherical shape or a flat plate shape. The average particle size is usually 1.3 to 5 mm, preferably 1.5 to 4.5 mm, and more preferably 1.6 to 4.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.3 to 4 mm and the diameter is about 1.3 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 chip is practically in the range of 10 to 30 mg / piece.

Thermoplastic polyesters generally contain a significant amount of fines, i.e. fines, which occur during the manufacturing process and have the same copolymer component content as the thermoplastic polyester chips. Such fines have the property of promoting crystallization of thermoplastic polyester, and when present in a large amount, the transparency of the polyester packaging material molded from the polyester composition containing such fines is very high. In the case of a bottle, there is a problem that the amount of shrinkage at the time of crystallization of the bottle cap portion does not fall within the specified value range and cannot be sealed with a cap. Therefore, it is desirable that the fine content in the thermoplastic polyester used in the present invention is 1000 ppm or less, preferably 500 ppm or less, more preferably 300 ppm or less, and particularly preferably 100 ppm or less.

The partially aromatic polyamide according to the present invention is mainly composed of a polyamide having a unit derived from an aliphatic dicarboxylic acid and an aromatic diamine as a main structural unit, or a unit derived from an aromatic dicarboxylic acid and an aliphatic diamine. Polyamide as a unit.

Examples of the aromatic dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, and diphenoxy. Examples include ethanedicarboxylic acid and functional derivatives thereof.

As the aliphatic dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention, a linear aliphatic dicarboxylic acid is preferable, and a linear aliphatic dicarboxylic acid having an alkylene group having 4 to 12 carbon atoms is particularly preferable. preferable. Examples of such linear aliphatic dicarboxylic acids include adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, spellic acid, azelaic acid, undecanoic acid, undecadioic acid, dodecanedioic acid , Dimer acids and functional derivatives thereof.

Examples of the aromatic diamine component constituting the partially aromatic polyamide according to the present invention include metaxylylenediamine, paraxylylenediamine, and para-bis- (2-aminoethyl) benzene.

The aliphatic diamine component constituting the partially aromatic polyamide according to the present invention is an aliphatic diamine having 2 to 12 carbon atoms or a functional derivative thereof. The aliphatic diamine may be a linear aliphatic diamine or a branched chain aliphatic diamine. Specific examples of such linear aliphatic diamines include ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, Examples include aliphatic diamines such as nonamethylenediamine, decamethylenediamine, undecamethylenediamine, and dodecamethylenediamine.

Moreover, as a dicarboxylic acid component which comprises the partial aromatic polyamide which concerns on this invention, alicyclic dicarboxylic acid can also be used other than the above aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Examples of the alicyclic dicarboxylic acid include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.

Moreover, as a diamine component which comprises the partial aromatic polyamide which concerns on this invention, an alicyclic diamine other than the above aromatic diamine and an aliphatic diamine can also be used. Examples of the alicyclic diamine include alicyclic diamines such as cyclohexanediamine and bis- (4,4′-aminohexyl) methane.

In addition to the diamine and dicarboxylic acid, lactams such as ε-caprolactam and laurolactam, aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. It can be used as a copolymerization component. In particular, the use of ε-caprolactam is desirable.

Preferred examples of the partially aromatic polyamide according to the present invention are derived from metaxylylenediamine or mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and an aliphatic dicarboxylic acid. A metaxylylene group-containing polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more in the molecular chain.

The partially aromatic polyamide according to the present invention may contain a structural unit derived from a polybasic carboxylic acid having 3 or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range. Good.

Examples of these polyamides include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene speramide, and metaxylylenediamine / adipic acid / isophthalic acid copolymers, metaxylylene. / Paraxylylene adipamide copolymer, metaxylylene / paraxylylene piperamide copolymer, metaxylylene / paraxylylene azelamide copolymer, metaxylylenediamine / adipic acid / isophthalic acid / ε-caprolactam copolymer And metaxylylenediamine / adipic acid / isophthalic acid / ω-aminocaproic acid copolymer.

In addition, other preferable examples of the partially aromatic polyamide according to the present invention include at least 20 mol% of a structural unit derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid in the molecular chain. More preferably, it is a polyamide containing 30 mol% or more, particularly preferably 40 mol% or more.

Examples of these polyamides include polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, hexamethylene diamine / terephthalic acid / isophthalic acid copolymer, polynonamethylene terephthalamide, polynonamethylene isophthalamide, nonamethylene diamine / terephthalic acid. / Isophthalic acid copolymer, nonamethylenediamine / terephthalic acid / adipic acid copolymer, and the like.

Other preferred examples of the partially aromatic polyamide according to the present invention include, in addition to at least one acid selected from aliphatic diamine and terephthalic acid or isophthalic acid, lactams such as ε-caprolactam and laurolactam, and aminocaproic acid. An aminocarboxylic acid such as aminoundecanoic acid, an aromatic aminocarboxylic acid such as para-aminomethylbenzoic acid or the like as a copolymerization component, and at least selected from an aliphatic diamine and terephthalic acid or isophthalic acid Polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more of a structural unit derived from one kind of acid in the molecular chain.

Examples of these polyamides include hexamethylenediamine / terephthalic acid / ε-caprolactam copolymer, hexamethylenediamine / isophthalic acid / ε-caprolactam copolymer, hexamethylenediamine / terephthalic acid / adipic acid / ε-caprolactam copolymer Examples include coalescence.

In the partially aromatic polyamide according to the present invention, an aqueous solution of an aminocarboxylate salt formed from a diamine and a dicarboxylic acid is heated under pressure and normal pressure to remove water and water generated by a polycondensation reaction in a molten state. It can be produced by a polycondensation method, or a method in which a diamine and a dicarboxylic acid are heated and polycondensed by reacting directly in a molten state under normal pressure or subsequently under vacuum. Further, by subjecting the polyamide chips obtained by the melt polycondensation reaction to solid phase polymerization, a partially aromatic polyamide having higher viscosity can be obtained.
The polycondensation reaction of the partially aromatic polyamide may be performed in a batch reaction apparatus or a continuous reaction apparatus.

In producing the partially aromatic polyamide used in the present invention, an alkali metal-containing compound represented by the following chemical formula (A) is added in order to improve the thermal stability and prevent gelation. The alkali metal atom content in the partially aromatic polyamide is preferably in the range of 1 to 1000 ppm.

Z-OR ₈ (A)
(However, Z is an alkali metal, R ₈ is hydrogen, an alkyl group, an aryl group, a cycloalkyl group, -C (O) CH ₃ or -C (O) OZ ', ( Z' is hydrogen, an alkali metal))

Examples of the alkali compound represented by the chemical formula (A) include sodium hydroxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium acetate, sodium carbonate, and alkaline earth Examples include alkaline earth compounds containing metals, but they are not limited to these compounds.

In the production of the partially aromatic polyamide, it is preferable to polymerize by adding a phosphorus compound as a stabilizer for preventing gelation due to thermal degradation.

When the phosphorus atom content derived from the phosphorus compound in the partially aromatic polyamide used in the present invention is X, the range is 0 <X ≦ 500 ppm. The lower limit is preferably 0.1 ppm, more preferably 1 ppm, and even more preferably 5 pm. The upper limit is preferably 400 ppm, more preferably 300 ppm, and even more preferably 250 ppm. When X is 0, that is, when no phosphorus atom is contained, the effect of preventing gelation during polycondensation is inferior. On the other hand, when X is more than 500 ppm, the gelation preventing effect is limited and it is uneconomical.
As the phosphorus compound added to the partially aromatic polyamide, it is preferable to use at least one selected from compounds represented by the following chemical formulas (B-1) to (B-4).

(Wherein R _{1 to} R ₇ are hydrogen, alkyl group, aryl group, cycloalkyl group or arylalkyl group, X _{1 to} X ₅ are hydrogen, alkyl group, aryl group, cycloalkyl group, arylalkyl group or alkali metal, Alternatively, _one of X _{1 to} X ₅ and R _{1 to} R ₇ 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 (B-1) include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, hypochlorous acid. Ethyl phosphate,

または

Or

の化合物およびこれらの加水分解物、ならびに上記ホスフィン酸化合物の縮合物などがある。

And hydrolysates thereof, and condensates of the above phosphinic acid compounds.

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

Examples of the phosphonic acid compound represented by the chemical formula (B-3) include phenylphosphonic acid, ethylphosphonic acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, ethylphosphone. Examples include potassium acid.
Examples of the phosphorous acid compound represented by the chemical formula (B-4) include phosphorous acid, sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid and the like. .

The content of total alkali metals in the partially aromatic polyamide used in the present invention (the total amount of alkali metal atoms contained in the phosphorus stabilizer and the amount of alkali metal atoms contained in the alkali metal compound) is The content of phosphorus atoms in the polyamide is preferably 1.0 to 6.0 times mol. The lower limit is more preferably 1.5 times mol, still more preferably 2.0 times mol, particularly preferably 2.3 times mol, most preferably 2.5 times mol, and the upper limit is more preferably 5.5 times mol. Mol, more preferably 5.0 times mol. When the total alkali metal content is less than 1.0 times the phosphorus atom content, gelation is likely to be promoted. On the other hand, if the total alkali metal content is more than 6.0 times the phosphorus atom content, the polymerization rate will be slow, the viscosity will not increase sufficiently, and gelation will be promoted especially in the reduced pressure system, which is uneconomical. is there.

The compounds represented by the chemical formula (A) and the chemical formulas (B-1) to (B-4) used in the present invention may be used alone, but the polyester composition is more preferably used in combination. This is preferable because thermal stability is improved.

In order to mix the phosphorus compound or the alkali metal-containing compound with the partially aromatic polyamide used in the present invention, the raw material before the polymerization of the polyamide, these may be added during the polymerization, or may be melt-mixed with the polymer. Good.
Moreover, these compounds may be added simultaneously or separately.

The relative viscosity of the partially aromatic polyamide used in the present invention is 1.3 to 4.0, preferably 1.5 to 3.0, more preferably 1.7 to 2.5, and still more preferably 1.8 to 3.0. The range is 2.0. When the relative viscosity is 1.3 or less, the molecular weight is too small, and the mechanical properties of the packaging material comprising the polyester composition of the present invention may be inferior. On the other hand, if the relative viscosity is 4.0 or more, it takes a long time to polymerize the polyamide, which may cause deterioration of the polymer and undesired coloration, and also causes a decrease in productivity and an increase in cost. Sometimes.

Further, when the terminal amino group concentration (μmol / g) of the partially aromatic polyamide used in the present invention is AEG and the terminal carboxyl group concentration (μmol / g) of the partially aromatic polyamide is CEG, the ratio of AEG to CEG (AEG / CEG) is preferably 1.0 or more. When the ratio of the terminal amino group concentration to the terminal carboxyl group concentration in the partially aromatic polyamide (AEG / CEG) is less than 1.0, the flavor retention of the polyester packaging material of the present invention is poor, and such polyester packaging The material may be impractical as a container for low flavor beverages. Further, when the ratio of the terminal amino group concentration to the terminal carboxyl group concentration (AEG / CEG) in the partially aromatic polyamide exceeds 20, it is not preferable because the obtained polyester packaging material becomes highly colored and loses commercial value.

The shape of the partially aromatic polyamide chip used in the present invention may be any of a cylinder shape, a square shape, a spherical shape, a flat plate shape, and the like. The average particle size is usually in the range of 1.0 to 5 mm, preferably 1.2 to 4.5 mm, more preferably 1.5 to 4.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.0 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 chip is practically in the range of 5 to 30 mg / piece.

The acetaldehyde content (A _t ) (ppm) of a molded product obtained by injection molding of the polyester composition of the present invention by the method described in the following measurement method (5), and the acetaldehyde of the polyester composition before injection molding The difference (A _t −A ₀ ) from the content (A ₀ ) (ppm) is preferably 20 ppm or less, preferably 15 ppm or less, more preferably 10 ppm or less, and most preferably 5 ppm or less. When the difference (A _t −A ₀ ) in the acetaldehyde content before and after injection molding exceeds 20 ppm, the flavor retention of the obtained polyester packaging material is deteriorated. In addition, the lower limit of the difference in acetaldehyde content before and after injection molding (A _t −A ₀ ) is 1 ppm, and in order to reduce it below this, the production conditions of the polyester packaging material must be made unproductive. It is uneconomical.

The polyester composition in which the difference (A _t −A ₀ ) between the acetaldehyde content (A _t ) after injection molding and the acetaldehyde content (A ₀ ) before injection molding is 20 ppm or less is a heat of which the acetaldehyde content is 5 ppm or less. It can be obtained by using, as a constituent component, a plastic polyester or a thermoplastic polyester having an acetaldehyde content of 10 ppm or less and having the remaining polycondensation catalyst deactivated. Examples of the method of deactivating the polycondensation catalyst in the thermoplastic polyester include a method of contacting the thermoplastic polyester chip with water, water vapor or water vapor-containing gas after melt polycondensation or after solid phase polymerization. Another method for deactivating the polycondensation catalyst is to inactivate the polymerization catalyst by adding and mixing the phosphorus compound to the melt of the polyester after melt polycondensation or solid phase polymerization.

Further, the polyester composition having the difference (A _t −A ₀ ) of 20 ppm or less is a polyester composition composed of a thermoplastic polyester having acetaldehyde content of 10 ppm or less and a partially aromatic polyamide. It can also be obtained by contact treatment.

The polyester packaging material of the present invention is characterized in that the content of alkali metal atoms in the polyester packaging material is in the range of 0.1 to 300 ppm.

The lower limit of the alkali metal atom content in the polyester packaging material is preferably 1 ppm, more preferably 5 ppm. The upper limit of the alkali metal atom content in the polyester packaging material is preferably 270 ppm, more preferably 250 ppm, and further preferably 200 ppm.

When the content of alkali metal atoms in the polyester packaging material is less than 0.1 ppm, coloring is intense, burnt lines and unmelted products are likely to be generated, and as a result, the appearance of the polyester packaging material is deteriorated. On the other hand, when the content of alkali metal atoms in the polyester packaging material is more than 300 ppm, the generation of burnt lines and unmelted material is hardly observed, but the transparency and flavor retention are deteriorated.

The acetaldehyde content in the polyester packaging material of the present invention is 20 ppm or less, preferably 15 ppm or less, more preferably 10 ppm or less. When the acetaldehyde content in the polyester packaging material of the present invention exceeds 20 ppm, the flavor retention of the polyester packaging material is deteriorated. In addition, the lower limit of the acetaldehyde content in the polyester packaging material is 3 ppm, and in order to reduce the content to less than this, there is a problem in that the molding is not considered profitable.

The polyester packaging material of the present invention has an increase in acetaldehyde content (ΔAA) (ppm) of 20 ppm or less, preferably 15 ppm or less, more preferably 13 ppm or less when melt-treated at 290 ° C. for 30 minutes. is there. When the amount of increase in acetaldehyde content (ΔAA) (ppm) when melt-treated exceeds 20 ppm, it is obtained when molding polyester packaging material using a part of recycled recovered products such as used PET bottles. It becomes very difficult to reduce the AA content of the obtained polyester packaging material to the target value, and the mixing ratio of the recycled recovered product to the virgin PET resin must be extremely reduced.

In order to maintain the increase amount (ΔCT ₂ ) of the cyclic ester trimer when the polyester packaging material is melt-treated at 290 ° C. for 30 minutes, it is melted at a temperature of 290 ° C. for 30 minutes. Use a thermoplastic polyester having a cyclic ester trimer increase (ΔCT ₁ ) of 0.40% by weight or less, preferably 0.35% by weight or less, more preferably 0.30% by weight or less when treated. is required. When a thermoplastic polyester having an increase in cyclic ester trimer (ΔCT ₁ ) of more than 0.40% by weight when melt-treated for 30 minutes at a temperature of 290 ° C. is used, the resin is melted when the polyester composition is molded. Occasionally, the amount of cyclic ester trimer increases, and depending on the heat treatment conditions, oligomer adhesion to the surface of the heating mold increases rapidly, and the transparency of the resulting hollow molded article is extremely deteriorated.

A thermoplastic polyester having an increase in cyclic ester trimer (ΔCT ₁ ) of 0.40% by weight or less when melt-treated for 30 minutes at a temperature of 290 ° C. is obtained after melt polycondensation or after solid-phase polymerization. The polycondensation catalyst remaining in the thermoplastic polyester can be produced by deactivation treatment. As a method for deactivating the polycondensation catalyst in the thermoplastic polyester, the same method as described above can be used.

When the thermoplastic polyester is PET, the cyclic ester trimer is a cyclic trimer composed of terephthalic acid and ethylene glycol.
The content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material of the present invention is preferably 0.70% by weight or less, more preferably 0.50% by weight or less, and further preferably 0.40% by weight. The following is preferable. When the content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material exceeds 0.70% by weight, the adhesion of the oligomer to the surface of the heating mold increases rapidly, and this is obtained. In addition, the transparency of the hollow molded body is extremely deteriorated, and the flavor retention is also deteriorated.

In order to maintain the content of the cyclic ester trimer derived from the thermoplastic polyester in the polyester packaging material at 0.70% by weight or less, the content of the cyclic ester trimer in the polyester composition is preferably It is necessary to be 0.70% by weight or less, more preferably 0.50% by weight or less, and still more preferably 0.40% by weight or less. When the polyester packaging material is a heat-resistant hollow molded body, if the content of the cyclic ester trimer in the polyester composition used for molding exceeds 0.70% by weight, the cyclic ester on the surface of the heating mold The adhesion of oligomers derived from polyesters such as trimers increases with time, and much effort is required for cleaning for mold cleaning, and at the same time, economic loss due to molding interruption is incurred. The lower limit is 0.10% by weight, and in order to reduce it to less than this, it is necessary to employ polyester production conditions that are not considered profitable, which is a problem.

The content of the metaxylylene group-containing cyclic amide monomer in the polyester packaging material of the present invention is 0.3% by weight or less, preferably 0.28% by weight or less, more preferably 0.25% by weight or less. . When the content of the cyclic amide monomer in the polyester packaging material exceeds 0.3% by weight, the flavor retention of the contents filled in the polyester packaging material is deteriorated, which is a problem.

In order to achieve this, the content of the metaxylylene group-containing cyclic amide monomer in the polyester composition of the present invention is 0.3% by weight or less, preferably 0.28% by weight or less, more preferably 0.25. It is preferable that it is below wt%.

When the content of the cyclic amide monomer in the polyester composition exceeds 0.3% by weight, the inner surface of the mold when molding the polyester packaging material with improved heat resistance, the gas outlet of the mold, and the exhaust pipe Mold contamination caused by foreign matter adhering to the surface becomes extremely severe. The lower limit of the content of the cyclic amide monomer in the polyester composition or the polyester packaging material is preferably 0.001 ppm for economic reasons. The cyclic amide monomer is measured by the high performance liquid chromatograph method described below.

The metaxylylene group-containing polyamide includes cyclic amide monomer, cyclic amide dimer, cyclic amide trimer, and cyclic amide tetramer composed of diamine and dicarboxylic acid used as starting materials. Examples include oligomers, unreacted monomers such as the dicarboxylic acid and the diamine, and linear oligomers such as a linear dimer and a linear trimer composed of the diamine and the dicarboxylic acid. The content varies depending on the polycondensation method, polycondensation conditions, or the molecular weight of the produced polyamide, but as an example, the cyclic amide monomer is 0.2 to 2.0% by weight, and the cyclic amide dimer is 0.2%. 1 to 2.0% by weight, cyclic amide trimer is 0.1 to 1.0% by weight, cyclic amide tetramer is 0.005 to 0.5% by weight, and linear oligomers are on the order of 1 to 5000 ppm. The unreacted monomers are in the order of 0.1 to 2000 ppm.

Here, when the metaxylylene group-containing polyamide is a polyamide composed of metaxylylenediamine and adipic acid, the chemical formula of the cyclic oligomer is represented by the following formula, and the case where n = 1 is a cyclic amide monomer. is there.

（上記式１中、ｎは１〜４の整数を表す。）

(In the above formula 1, n represents an integer of 1 to 4.)

The method for adjusting the content of the cyclic amide monomer in the polyester composition or the polyester packaging material of the present invention to the above value is not particularly limited, and can be produced, for example, as follows. That is, according to the compounding amount of the metaxylylene group-containing polyamide with respect to the thermoplastic polyester, so that the content of the cyclic amide monomer in the polyester composition or the polyester packaging material satisfies the value of the claims of the present invention, This can be achieved by using a metaxylylene group-containing polyamide having a reduced cyclic amide monomer content. It can also be achieved by extracting and removing the above-mentioned cyclic body from a polyester composition containing a metaxylylene group-containing polyamide or a polyester packaging material obtained from the polyester composition with water or an organic solvent. There is no limitation on the method for producing the metaxylylene group-containing polyamide having a small cyclic amide monomer content, such as extraction with water or an organic solvent, change of polycondensation conditions, heat treatment under reduced pressure, and a combination of these methods. Can mention

The intrinsic viscosity of the polyester packaging material of the present invention is preferably 0.55 to 1.00 deciliter / gram, more preferably 0.58 to 0.95 deciliter / gram, and even more preferably 0.60 to 0.90 deciliter / gram. In the gram range.

In the polyester composition of the invention, other additives such as known ultraviolet absorbers, antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from the outside, and internal precipitates during the reaction were optionally added to the polyester composition of the invention. Various additives such as lubricants, mold release agents, nucleating agents, stabilizers, antistatic agents, dyes and pigments may be blended. It is also possible to mix ultraviolet ray-blocking resin, heat-resistant resin, recovered products from used polyethylene terephthalate bottles, and the like at an appropriate ratio.

Further, when the polyester packaging material of the present invention is a film, the polyester composition contains calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate in order to improve handling properties such as slipperiness, rollability and blocking resistance. , Inorganic particles such as barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, organic salt particles such as terephthalate such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, divinylbenzene, styrene, acrylic acid, methacrylic Inactive particles such as crosslinked polymer particles such as homopolymers or copolymers of vinyl monomers of acid, acrylic acid or methacrylic acid can be incorporated.
The polyester packaging material of the present invention can be obtained by a known production method.

In the following, as a representative example, when the thermoplastic polyester is polyethylene terephthalate (PET), simple methods for producing various polyester packaging materials will be described. The resin composition for a polyester packaging material of the present invention can be obtained by mixing the thermoplastic polyester and the polyamide by a conventionally known method. For example, the polyamide chip and the thermoplastic polyester chip are dry blended with a tumbler, V-type blender, Henschel mixer or the like, and the dry blended mixture is once with a single screw extruder, twin screw extruder, kneader, etc. Examples thereof include those obtained by melt mixing as described above, and those obtained by subjecting the melt mixture to solid phase polymerization under a high vacuum or an inert gas atmosphere as necessary.

Further, the polyamide may be crushed and used. This is particularly advantageous in the case of a composition using a small amount of the polyamide. The particle size when pulverized is preferably about 10 mesh or less. Also, a method in which a solution obtained by dissolving the polyamide in a solvent such as hexafluoroisopropanol is attached to the surface of a thermoplastic polyester chip, and the thermoplastic polyester is brought into contact with the member in a space where the polyamide member is present. And a method of attaching the polyamide to the surface of the thermoplastic polyester chip.

When the polyester packaging material of the present invention is a sheet-like material, for example, it can be produced using a general sheet molding machine equipped with an extruder and a die.
Further, the sheet-like material can be formed into a cup shape or a tray shape by pressure forming or vacuum forming. Moreover, the polyester packaging material of this invention can be used also for the use of the tray-shaped container for cooking food with a microwave oven and / or an oven range, or heating frozen food. In this case, after the sheet-like material is formed into a tray shape, it is thermally crystallized to improve heat resistance.

When the polyester packaging material of the present invention is a stretched film, a sheet-like material obtained by injection molding or extrusion molding is usually selected from uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching used for PET stretching. It shape | molds using arbitrary extending | stretching methods.

In producing a stretched film, the stretching temperature is usually 80 to 130 ° C. Stretching may be uniaxial or biaxial, but biaxial stretching is preferred from the viewpoint of film physical properties. In the case of uniaxial stretching, the stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 8 times. In the case of biaxial stretching, the longitudinal and transverse directions are usually 1.1 to 8 times, respectively. Preferably, it may be performed in a range of 1.5 to 5 times. The vertical / horizontal magnification is usually 0.5 to 2, preferably 0.7 to 1.3. The obtained stretched film can be further heat-set to improve heat resistance and mechanical strength. The heat setting is usually performed under tension at 120 to 240 ° C., preferably 150 to 230 ° C., usually for several seconds to several hours, preferably several tens of seconds to several minutes.

In producing the hollow molded body, a preform molded from the PET composition of the present invention is stretch blow molded, and an apparatus conventionally used in blow molding of PET can be used. Specifically, for example, once a preform is formed by injection molding or extrusion molding, the plug part and the bottom part are processed as it is, and then reheated, and then biaxial stretch blow molding such as hot parison method or cold parison method The law applies. The molding temperature in this case, specifically, the temperature of each part of the cylinder of the molding machine and the nozzle is usually in the range of 260 to 310 ° C. The stretching temperature is usually 70 to 120 ° C., preferably 90 to 110 ° C., and the stretching ratio is usually 1.5 to 3.5 times in the longitudinal direction and 2 to 5 times in the circumferential direction. The obtained hollow molded body can be used as it is, but in particular in the case of beverages that require hot filling, such as fruit juice beverages and oolong teas, in general, heat-setting treatment is performed in a blow mold, Used to impart sex. The heat setting is usually performed at 100 to 200 ° C., preferably 120 to 180 ° C., for several seconds to several hours, preferably for several seconds to several minutes, under tension by compressed air or the like.

In order to impart heat resistance to the plug part, the plug part of the preform obtained by injection molding or extrusion molding is crystallized in a far infrared or near infrared heater installation oven, Alternatively, the mouthpiece is crystallized with the above heater after molding the bottle.

Moreover, the polyester packaging material of this invention can be one structure layers, such as a laminated molded object and a laminated film. In particular, it is used for containers and the like in the form of a laminate with PET. Examples of laminated molded products include a two-layer structure composed of two layers of an outer layer made of the polyester packaging material of the present invention and a PET inner layer, or composed of two layers of an inner layer made of the polyester packaging material of the present invention and an outer PET layer. A molded article having a two-layer structure, a three-layer structure comprising an intermediate layer containing the polyester packaging material of the present invention and an outer layer and an innermost layer of PET, or an intermediate layer between the outer layer and innermost layer containing the polyester packaging material of the present invention and PET Examples include a three-layered molded body composed of layers, a five-layered molded body composed of an intermediate layer containing the polyester packaging material of the present invention, an innermost layer of PET, a central layer, and an innermost layer. In the PET layer, other gas barrier resins, ultraviolet blocking resins, heat resistant resins, recovered products from used polyethylene terephthalate bottles, and the like can be mixed and used at an appropriate ratio.

Other examples of the laminated molded body include a laminated molded body with a resin other than a thermoplastic polyester such as polyolefin, and a laminated molded body with a different base material such as paper or a metal plate.

There is no restriction | limiting in particular in the thickness of the said laminated molded object, and the thickness of each layer. The laminated molded body can be used in various shapes such as a sheet-like material, a film-like material, a plate-like material, a hollow body, and a container.

The laminate can be produced by co-extrusion using a number of extruders corresponding to the type of the resin layer and a multi-layered multi-die, or with a number of injection machines corresponding to the type of the resin layer. It can also be done by co-injection using an injection runner and injection mold.

The polyester packaging material of the present invention can be a film laminated on one or both sides of a laminated metal plate. Examples of the metal plate used include tinplate, tin-free steel, and aluminum.

As a laminating method, a conventionally known method can be applied, and it is not particularly limited, but it is preferable to carry out by a thermal laminating method that can achieve organic solvent-free and can avoid adverse effects on the taste and odor of food products due to the residual solvent. In particular, the thermal laminating method by energization processing of a metal plate is particularly recommended. In the case of double-sided lamination, they may be laminated simultaneously or sequentially.
Needless to say, a film can be laminated to a metal plate using an adhesive.

Moreover, a metal container is obtained by shape | molding using the said laminated metal plate. The method for forming the metal container is not particularly limited. Further, the shape of the metal container is not particularly limited, but is preferably applied to a so-called two-piece can made by a molding process such as drawing, squeezing and ironing, and stretch draw molding. The present invention can also be applied to a so-called three-piece can in which a top cover suitable for filling a food product such as a coffee drink is wrapped to fill the contents.
The main characteristic value measuring methods in the present invention will be described below.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The main characteristic value measuring methods in this specification will be described below.

(Evaluation methods)
(1) Intrinsic viscosity (IV) of polyester, polyester composition and polyester packaging material
It calculated | required from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent. (Unit is deciliter / gram)

(2) The content of dialkylene glycol copolymerized in polyester is decomposed by methanol, the amount of dialkylene glycol is quantified by gas chromatography, and the ratio (mol%) to the total glycol components is determined. expressed. In the case of PET, the content is DEG, and in the case of PTT, the content is DPG.

(3) Content of polyester, polyester composition and cyclic ester oligomer of polyester packaging material (% by weight)
300 mg of a sample is dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixed solution (volume ratio = 2/3), and further diluted with 30 ml of chloroform. To this is added 15 ml of methanol to precipitate the polymer, followed by filtration. The filtrate was evaporated to dryness, made up to a constant volume with 10 ml of dimethylformamide, and cyclic ester oligomers were quantified by high performance liquid chromatography. In the case of PET, it is a cyclic trimer (CT content), and in the case of PTT, it is a cyclic dimer (CD content).

(4) Acetaldehyde content of polyester, polyester composition and polyester packaging material (hereinafter referred to as “AA content”) (ppm)
After putting sample / distilled water = 1 gram / 2 cc into a glass ampule substituted with nitrogen, seal the top of the ampule under a nitrogen seal and perform extraction treatment at 160 ° C for 2 hours. After cooling, the acetaldehyde in the extract is increased. It was measured by sensitivity gas chromatography and the concentration was expressed in ppm.

(5) Difference in acetaldehyde content before and after injection molding of the polyester composition (hereinafter referred to as “A _t −A ₀ ”) (ppm)
A stepped flat plate mold (surface) which was cooled with 10 ° C. water at a cylinder temperature of 290 ° C. using a M-150C (DM) injection molding machine manufactured by Meiki Seisakusho. The stepped shaped plate is injection molded using a temperature of about 22 ° C. The obtained stepped molded plate is provided with a plate of about 3 cm × about 5 cm square having a thickness of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 mm in a step shape. Is about 146 g. A sample is taken from a 2 mm thick plate, the acetaldehyde content (A _t ) is determined by the measurement method (4), and the difference in acetaldehyde content before and after injection molding is determined from the following equation.
Difference in acetaldehyde content before and after injection molding (A _t −A ₀ ) (ppm) =
Acetaldehyde content (A _t ) (ppm) of stepped molded plate after injection molding-Acetaldehyde content (A ₀ ) (ppm) of dried polyester composition before injection molding

(6) Amount of increase in acetaldehyde content during melting treatment of polyester packaging material (hereinafter referred to as “ΔAA”) (ppm)
A 3g sample of about 1 to 3 mm square is taken from the polyester packaging material, put in a glass test tube, vacuum dried at about 50 to 70 ° C, and then immersed in an oil bath at 290 ° C for 30 minutes under a normal pressure nitrogen atmosphere. And melt processing. The amount of increase in the acetaldehyde content during the melting process is determined by the following formula.
Increase in acetaldehyde content during melt treatment (ppm) =
Acetaldehyde content after melt treatment (ppm)-Acetaldehyde content after drying before melt treatment (ppm)

(7) Increase amount of cyclic ester trimer (hereinafter referred to as “ΔCT ₁ amount”) (% by weight) at the time of the melt treatment of polyester and weight increase amount of cyclic ester trimer (hereinafter referred to as “Δ” at the time of the melt treatment of the polyester packaging material). CT ₂ ”) (wt%)

3 g of the dried polyester chip or polyester packaging material is put into a glass test tube and immersed in an oil bath at 290 ° C. for 30 minutes under a normal pressure nitrogen atmosphere and melt-treated. The polyester packaging material is cut into a size of about 1 to 3 mm square and used for measurement.

The cyclic ester trimer increase amount (ΔCT ₁ amount) during the polyester melt treatment and the cyclic ester trimer increase amount (ΔCT ₂ amount) during the melt treatment of the polyester packaging material are determined by the following equations.
Increase amount of cyclic ester trimer during melt treatment (wt%) =
Cyclic ester trimer content after melt treatment (wt%)-cyclic ester trimer content before melt processing (wt%)

(8) Relative viscosity of partially aromatic polyamide (hereinafter referred to as “Rv”)
0.25 g of a sample was dissolved in 25 ml of 96% sulfuric acid, and 10 ml of this solution was measured at 20 ° C. with an Ostwald viscosity tube and obtained from the following formula.
Rv = t / t ₀
t ₀ : solvent falling time t : Sample solution dropping seconds

(9) Sodium atom content (hereinafter referred to as “Na content”) of partially aromatic polyamide, polyester composition and polyester packaging material
The sample is incinerated and decomposed with a platinum crucible, 6 mol / L hydrochloric acid is added and evaporated to dryness. It was determined by dissolving with 1.2 mol / L hydrochloric acid and quantifying by atomic absorption.

(10) Fine content measurement About 0.5 kg of resin is placed on a sieve (diameter 30 cm) with a wire mesh of 1.7 mm in nominal size according to JIS-Z8801, and a swing type sieve shaker made by Terraoka. Sifted with a machine SNF-7 at 1800 rpm for 1 minute. This operation was repeated and a total of 20 kg of resin was sieved.
The fine sieved under the sieve was collected with ion-exchanged water and filtered through a G1 glass filter manufactured by Iwaki Glass. These were dried together with a glass filter in a dryer at 100 ° C. for 2 hours, then cooled and weighed. Again, the same operations of washing and drying with ion-exchanged water were repeated to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain the fine weight. The fine content is the fine weight / the total resin weight that has been sieved.

(11) Evaluation of mold dirt A predetermined amount of thermoplastic polyester chips dried by a dryer using nitrogen gas and a predetermined amount of partially aromatic polyamide dried by a dryer using nitrogen gas were dry-blended. The preform was molded at a resin temperature of 285 ° C. using an M-150C (DM) injection molding machine manufactured by Meiki Seisakusho. The preform plug portion was heated and crystallized with a home-made plug portion crystallization apparatus, and then biaxially stretched blow-molded using a Copoplast LB-01E stretch blow molding machine. It was heat-set in a mold set at about 145 ° C. to obtain a 1000 cc hollow molded body. Under the same conditions, 2000 hollow molded articles were continuously stretch blow molded, and the state of the mold surface before and after that was visually observed and evaluated as follows.
◎: No change before and after the continuous molding test ○: Slightly adhered after the continuous molding test △: Very much adhered after the continuous molding test ×: Very much adhered after the continuous molding test

(12) Transparency of hollow molded body a) Non-heat resistant hollow molded body: The appearance of the hollow molded body molded by the method described in Example 1 was visually observed and evaluated according to the following evaluation criteria.
b) Heat-resistant hollow molded article: The appearance of the hollow molded article obtained after the molding of (13) was visually observed and evaluated according to the following evaluation criteria. Short-term transparency was evaluated after 10 moldings, and continuous molding transparency was evaluated after 2000.
(Evaluation criteria)
◎: Transparent ○: Transparent within a practical range and no foreign matter such as unmelted material is seen Δ: Transparent within a practical range, but foreign material such as an unmelted material is observed.
X: Inferior in transparency, coloring is observed, or unmelted material is seen

(13) Sensory test a) Non-heat-resistant hollow molded article: After boiling distilled water was cooled to 50 ° C, it was put into the hollow molded article and held for 30 minutes after sealing, and then left at 50 ° C for 10 days. Odor tests were conducted. Use distilled water as a blank for comparison. The sensory test was carried out by 10 panelists according to the following criteria, and the average values were compared.
b) Heat-resistant hollow molded article: Distilled water boiled in the hollow molded article was held for 30 minutes after sealing and then left at 50 ° C. for 5 days. After opening, flavor and odor were tested in the same manner as described above.
(Evaluation criteria)
◎: Feel no strange taste or smell ○: Feel a slight difference from the blank △: Feel a difference from the blank ×: Feel a considerable difference from the blank XX: Feel a very large difference from the blank

(14) Oxygen permeation rate (cc / one container / 24 hr / atm)
The permeation amount per 1000 cc bottle was measured at 20 ° C. and 0% RH with an oxygen permeation meter OX-TRAN100 manufactured by Modern Controls.
(Polyethylene terephthalate (PET) used in Examples and Comparative Examples)
Table 1 shows the characteristics of PET (A) to (E) used in the evaluation test of the hollow molded body. These PETs are polymerized by a continuous melt polycondensation-solid phase polymerization apparatus using a Ge-based catalyst.
The PET content of these PET is about 2.8 mol%, the fine content of PET (A) to (C) is about 70 ppm or less, and the fine content of PET (D) and (E) is about 500 ppm. Met.

(Metaxylylene group-containing polyamide used in Examples and Comparative Examples (Ny-MXD6))
Table 2 shows the characteristics of Ny-MXD6 (F) to Ny-MXD6 (I) used in the test.
Ny-MXD6 (F) to Ny-MXD6 (H) heat metaxylylenediamine and adipic acid under pressure and normal pressure in the presence of NaOH or NaH ₂ PO ₂ .H ₂ O in a pressure-resistant polycondensation vessel. Then, it is obtained by a batch method of polycondensation. The total amount of sodium atoms of sodium hypophosphite and sodium hydroxide was 3.0 moles of phosphorus atoms.
Ny-MXD6 (I) is also obtained by the same polymerization method as Ny-MXD6 (H). The above phosphorus atom-containing compound and alkali compound were not added. The secondary transition point of these Ny-MXD6 is about 65 ° C.

(Example 1)
Using 2 parts by weight of Ny-MXD6 (G) with respect to 100 parts by weight of PET (C), these were each dry-blended by the drying method described in Evaluation Method (12) and then used, and manufactured by Meiki Seisakusho. A preform was molded at a resin temperature of 285 ° C. using an M-150C (DM) injection molding machine. The preform was biaxially stretch blow molded using a LB-01E stretch blow molding machine manufactured by Copoplast to obtain a 2000 cc non-heat resistant hollow molded body.

Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition is 2 ppm, the difference in acetaldehyde content before and after injection molding (A _t -A ₀ ) is 8 ppm, the AA content of the hollow molded body is 10 ppm, the sensory test evaluation is “「 ”, transparent As a result, a hollow molded article having excellent transparency and flavor retention could be obtained.

(Example 2)
A 2000 cc hollow molded body was molded and evaluated in the same manner as Example 1 using 10 parts by weight of Ny-MXD6 (F) per 100 parts by weight of PET (C).
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition is 59 ppm, the difference in acetaldehyde content before and after injection molding (A _t −A ₀ ) is 6 ppm, the AA content of the hollow molded body is 8 ppm, the sensory test evaluation is “◯”, transparent The property was “◎” and there was no problem. Oxygen barrier properties are also improved.

(Example 3)
A hollow molded body was molded and evaluated in the same manner as in Example 1 using 30 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (C).
Table 3 shows the valence results of the characteristics of the obtained hollow molded body.
The sodium content of the polyester composition is 150 ppm, the difference in acetaldehyde content before and after injection molding (A _t −A ₀ ) is 5 ppm, the AA content of the hollow molded body is 6 ppm, the sensory test evaluation is “◯”, transparent Sex was “◯” and there was no problem.

(Comparative Example 1)
A hollow molded body was molded and evaluated in the same manner as in Example 1 using 10 parts by weight of Ny-MXD6 (I) with respect to 100 parts by weight of PET (D).
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The sodium content of the polyester composition is 0 ppm, the difference in the acetaldehyde content before and after injection molding (A _t -A ₀ ) is 18 ppm, the AA content of the hollow molded body is 22 ppm, and the transparency is “× (colored unmelted) The sensory test evaluation was as bad as “×” and was not practical.

(Comparative Example 2)
A hollow molded body was molded and evaluated in the same manner as in Example 1 using 30 parts by weight of Ny-MXD6 (H) with respect to 100 parts by weight of PET (E).
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.
The polyester composition had a sodium content of 346 ppm, the difference in acetaldehyde content before and after injection molding (A _t −A ₀ ) was 11 ppm, and the hollow molded body had an AA content of 15 ppm. (Inferior in transparency) ”, the sensory test evaluation was bad as“ XX ”and was not practical.

(Comparative Example 3)
Using 100 parts by weight of PET (D), a hollow molded body was molded and evaluated in the same manner as in Example 1.
Table 3 shows the evaluation results of the properties of the obtained hollow molded body.

Example 4
Using 10 parts by weight of Ny-MXD6 (G) with respect to 100 parts by weight of PET (A), a hollow molded body was molded by the method of evaluation method (12), and mold contamination was also evaluated.
Table 4 shows the characteristics of the obtained hollow molded article and the evaluation results of mold contamination.
The difference in the acetaldehyde content before and after injection molding of the polyester composition (A _t −A ₀ ) is 5 ppm, the sodium content of the hollow molded body is 11 ppm, the AA content of the hollow molded body is 9 ppm, and the ΔAA content is 10 ppm, cyclic ester trimer content is 0.32 wt%, cyclic ester trimer content increase (ΔCT ₂ amount) is 0.04 wt%, CM content is 530 ppm, sensory test evaluation is “ “O”, transparency was “O”, and no mold deposits were observed.

(Example 5)
Using 20 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (B), a hollow molded body was molded by the method of evaluation method (12), and mold contamination was also evaluated.
Table 4 shows the characteristics of the obtained hollow molded article and the evaluation results of mold contamination.
The difference in the acetaldehyde content before and after injection molding of the polyester composition (A _t −A ₀ ) is 5 ppm, the sodium content of the hollow molded body is 108 ppm, the AA content of the hollow molded body is 7 ppm, and the ΔAA content is 10 ppm, cyclic ester trimer content is 0.34 wt%, cyclic ester trimer content increase (ΔCT ₂ amount) is 0.09 wt%, CM content is 1100 ppm, sensory test evaluation is “ “O”, transparency was “O”, and no mold deposits were observed.

(Example 6)
Using 30 parts by weight of Ny-MXD6 (F) with respect to 100 parts by weight of PET (A), a hollow molded body was molded by the method of evaluation method (12), and mold contamination was also evaluated.
Table 4 shows the characteristics of the obtained hollow molded article and the evaluation results of mold contamination.
The difference in the acetaldehyde content before and after injection molding of the polyester composition (A _t −A ₀ ) is 4 ppm, the sodium content of the hollow molded body is 150 ppm, the AA content of the hollow molded body is 5 ppm, and the ΔAA content is 8 ppm, cyclic ester trimer content is 0.31% by weight, cyclic ester trimer content increase (ΔCT ₂ amount) is 0.05% by weight, CM content is 1400 ppm, sensory test evaluation is “ “O”, transparency was “O”, and no mold deposits were observed.

(Comparative Example 4)
Using 0.05 parts by weight of Ny-MXD6 (I) with respect to 100 parts by weight of PET (D), a hollow molded body was molded by the method of evaluation method (12), and mold contamination was also evaluated.
Table 4 shows the characteristics of the obtained hollow molded article and the evaluation results of mold contamination.
The difference (A _t −A ₀ ) in the acetaldehyde content before and after the injection molding of the polyester composition is 27 ppm, the phosphorus content of the hollow molded body is 0 ppm, the AA content of the hollow molded body is 41 ppm, and the ΔAA content is 35 ppm, cyclic ester trimer content is 0.76% by weight, cyclic ester trimer content increase (ΔCT ₂ amount) is 0.50% by weight, sensory test evaluation is “XX”, transparency Was bad as “×” and the mold was dirty.

(Comparative Example 5)
Using 30 parts by weight of Ny-MXD6 (H) with respect to 100 parts by weight of PET (E), a hollow molded body was molded by the method of evaluation method (12), and mold contamination was also evaluated.
Table 4 shows the characteristics of the obtained hollow molded article and the evaluation results of mold contamination.
The difference (A _t −A ₀ ) in the acetaldehyde content before and after injection molding of the polyester composition is 7 ppm, the sodium content of the hollow molded body is 346 ppm, the AA content of the hollow molded body is 13 ppm, and the ΔAA content is 18 ppm, cyclic ester trimer content is 0.79 wt%, cyclic ester trimer content increase (ΔCT ₂ amount) is 0.52 wt%, CM content is 3800 ppm, sensory test evaluation is “ Xx ", transparency was bad as" x ", and mold contamination was also severe.

According to the polyester composition of the present invention, a polyester packaging material excellent in transparency, heat stability and flavor retention, or transparency, heat stability, flavor retention and gas barrier property can be obtained. As described above, the polyester packaging material is very suitable as a packaging material for beverages such as soft drinks, can be used in a wide range of fields, and greatly contributes to the industry.

Claims (3)

A polyester composition comprising 100 parts by weight of a thermoplastic polyester and 0.1 to 50 parts by weight of a partially aromatic polyamide, wherein the alkali metal atom content in the polyester composition is in the range of 0.1 to 300 ppm. And a ratio of the terminal amino group concentration to the terminal carboxyl group concentration in the partially aromatic polyamide is 1.0 to 20. A polyester packaging material obtained by molding the polyester composition according to claim 1. A polyester packaging material according to claim 2, wherein the polyester packaging material is a hollow molded body, a sheet-like material, or a stretched film obtained by stretching the sheet-like material in at least one direction.