JP2007002239A - Polyester composition and molded polyester article made thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition having excellent transparency, little variation of the transparency and suppressed formation of aldehydes such as acetaldehyde and cyclic ester oligomers in molding and capable of efficiently producing a blow molded product having excellent pressure resistance and high-temperature pressure resistance by high-speed molding and provide a molded polyester article produced by using the composition. <P>SOLUTION: The polyester composition is composed mainly of at least two kinds of polyesters containing ethylene arylate as main repeating unit, wherein the intrinsic viscosity difference of the polyesters is 0.05-0.25 dL/g, the temperature-descending crystallization temperature difference of the polyesters is ≤20°C and the content of the atom used as a polycondensation catalyst in the polyester composition satisfies the following formula (1): 1≤(A/25)+(B/5)+(C/3)+D≤15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a polyester that is suitably used as a raw material for hollow molded articles including beverage bottles, sheet-like articles, stretched films, and the like, particularly the production of aldehydes such as acetaldehyde and cyclic ester oligomers during molding. The present invention relates to a polyester which is suppressed, gives a molded article having excellent transparency and little fluctuation in transparency, a polyester composition comprising the same, and a polyester molded article having excellent heat resistance. In addition, the present invention relates to a polyester or a polyester composition that has less heat-treatment mold contamination when molding a hollow molded body and has excellent long-term continuous moldability.

As a material for containers, particularly containers such as seasonings, oils, beverages, cosmetics, and detergents, various resins are employed depending on the type of filling contents and the purpose of use. Among these, polyester, particularly polyethylene terephthalate (hereinafter sometimes abbreviated as PET) is excellent in chemical properties, mechanical strength, heat resistance, transparency, and gas barrier properties. It is most suitable as a material for molded articles such as beverage filling containers such as soft drinks and carbonated drinks.
For example, such a 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 for soft drinks. It can be formed into a hollow molded container, or it can be molded into a heat-resistant or pressure-resistant hollow molded container by heat-treating the preform plug part after heat treatment (crystallization of the plug part) and heat-treating the body part (heat setting). Is common. In order to improve the heat resistance of the bottle body, for example, a method of heat-treating the stretch blow mold at a high temperature is employed (see, for example, Patent Document 1). However, if a large number of bottles are continuously formed using the same mold by such a method, the bottle obtained with a long time operation is whitened, the transparency is lowered, and only a bottle having no commercial value can be obtained. . It has been found that this is because a deposit due to PET is attached to the mold surface, resulting in mold fouling, and this mold fouling is transferred to the bottle surface. In particular, in recent years, the molding speed has been increased along with the downsizing of the bottle. From the viewpoint of productivity, the melting time at the time of injection molding is shortened, the heating time for crystallization of the plug portion is shortened, or the mold. Contamination has become a greater problem and is not satisfactory with conventional PET, and a solution is desired.

  In the case of PET with respect to such a problem of mold contamination, conventionally, a method of reducing the cyclic trimer, which is the main component of the deposit on the mold surface, by solid-phase polymerization in advance (for example, In this method, the cyclic trimer is regenerated when it is remelted and preformed, and its effect is insufficient. Also disclosed are a method of deactivating a catalyst by contacting PET with water (see, for example, Patent Document 4) and a PET having a catalyst deactivated by treating with water (see, for example, Patent Document 5). Yes. However, even with the above method, the amount of cyclic oligomers generated at the time of melting is reduced and the mold fouling is temporarily reduced. However, the crystallization speed is unstable, and defects such as whitened flow patterns and bubbles occur. There is a problem that only bottles that are easy and have poor transparency can be obtained, and a solution is awaited.

  Further, 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 recent years, polyester containers such as 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 it is becoming increasingly important to reduce the acetaldehyde content of the beverage container. In addition, for metal cans for beverages, for the purpose of process simplification, hygiene, pollution prevention, etc., there is a method of making cans using a metal plate whose inner surface is coated with a polyester film whose main repeating unit is ethylene terephthalate. It has come to be adopted. In this case as well, the contents are filled and sterilized by heating at a high temperature. At this time, it is found that the use of a film having a sufficiently low acetaldehyde content is an essential requirement for improving the flavor and odor of the contents. I came.

  For these reasons, various measures have been taken to reduce the acetaldehyde content in the polyester. As these measures, for example, a method of reducing the AA content by solid-phase polymerization of melt-polycondensed polyester (see, for example, Patent Document 6), AA at the time of molding using a copolyester having a lower melting point A method of reducing the production (for example, see Patent Document 7), a method of using a polyester composition in which 0.05 parts by weight or more and less than 1 part by weight of a metaxylylene group-containing polyamide resin is added to 100 parts by weight of the polyester resin (for example, , Patent Document 8), a polyester container (for example, see Patent Document 9), a polyester prepolymer comprising a polyester composition containing a thermoplastic polyester and a specific polyamide whose terminal amino group concentration is regulated within a certain range. After conditioning the moisture content to 2000 ppm or more, crystallization and solid phase polymerization A method (for example, see Patent Document 10), a method in which polyester particles are treated with hot water at 50 to 200 ° C. and then heat-treated under reduced pressure or in an inert gas flow (for example, see Patent Document 11), during thermoforming There have been proposed a method for reducing the molding temperature as much as possible and a method for reducing the shear stress during thermoforming as much as possible. However, even in a molded body using polyester obtained by these methods, it cannot be said that oligomers and acetaldehyde can be reduced to a problem-free level, and the problem remains unsolved. In addition, a blend of solid-phase-polymerized PET and copolymerized polyethylene terephthalate obtained by copolymerizing 3 to 20 mol% of a copolymer component (for example, see Patent Document 12) has been proposed. Although it is said that AA content can be reduced, since a copolymerization component exists, there is a problem in the heat resistance and pressure resistance of the obtained molded body, and it is not satisfactory and a solution is awaited.

In recent years, thinning of bottles has been attempted, and as a result, attempts have been made to increase the molecular weight in order to increase the strength of the bottle, but by increasing the molecular weight, the melt viscosity during molding increases and the amount of acetaldehyde generated increases. There was an increasing problem.
Japanese Examined Patent Publication No.59-6216 JP 55-89330 A JP 55-89331 A Japanese Patent Laid-Open No. 3-47830 Japanese Patent Laid-Open No. 3-72524 JP-A-53-73288 Japanese Patent Laid-Open No. 57-16024 Japanese Examined Patent Publication No. 6-6661 Japanese Examined Patent Publication No. 4-71425 JP-A-2-298512 JP-A-8-120062 JP 58-45254 A

  The present invention solves the problems of the conventional polyester composition, the formation of aldehydes and cyclic ester oligomers such as acetaldehyde during molding is suppressed, excellent in transparency and little variation in transparency, It is an object of the present invention to provide a polyester composition that can efficiently produce a hollow molded article having excellent heat-resistant dimensional stability by high-speed molding while suppressing contamination of a heating mold during molding, and a polyester molded article comprising the same. .

The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object. That is, the polyester composition of the present invention is a polyester composition containing, as a main component, at least two types of polyesters mainly composed of ethylene arylate, and the difference in intrinsic viscosity between the polyesters is 0.05 to 0. .25 deciliter / gram, the difference in the crystallization temperature when the polyester is cooled is within 20 ° C., and the content of atoms used as the polycondensation catalyst in the polyester composition satisfies the following formula (1): It is characterized by that.
1 ≦ (A / 25) + (B / 5) + (C / 3) + D ≦ 15 (1)
(In the formula, A, B, C and D are respectively an antimony (hereinafter sometimes abbreviated as Sb) atom content and a germanium (hereinafter abbreviated as Ge) atom content in the polyester composition. Amount, aluminum (hereinafter abbreviated as “Al”) atomic content, titanium (hereinafter abbreviated as “Ti”) atomic content (unit: ppm)

  Here, the polyester composition of the present invention can contain at least one selected from the above catalysts as a polycondensation catalyst within a range satisfying the above formula (1), and these catalysts can be contained in the above formula (1). ) May be contained in appropriate combinations within a range that satisfies the above.

In this case, the relationship between the phosphorus atom content E in the polyester composition and A, B, C, D can satisfy the following formula (2).
0.1 ≦ {(A / 25) + (B / 5) + (C / 3) + D} / E ≦ 5 (2)
(In the formula, E represents the phosphorus atom content in the polyester composition. The unit is ppm)

  Moreover, the terminal carboxyl group density | concentration with respect to the total number of terminal groups of each polyester can be 5-40 equivalent%.

  Moreover, the cyclic ester oligomer content of the polyester composition can be 70% or less of the cyclic ester oligomer content of the melt polycondensation polyester prepolymer.

  Moreover, the ratio of the average weight (W) and average weight (W) of each polyester chip may be 5 to 50 mg and 1.00 to 1.30, respectively.

Further, the polyester composition is a polyester composition having ethylene terephthalate as a main repeating unit, comprising the following polyester A and polyester B as main components, the crystallization temperature of polyester A at elevated temperature and polyester B The difference between the crystallization temperature and the crystallization temperature may be within 10 ° C.
Polyester A: Intrinsic Viscosity IV _A is 0.60 to 0.80 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at temperature increase measured by DSC is 140 to 180 ° C., and crystallization temperature at temperature decrease is 160 to 160 ° C. Polyester at 200 ° C.
Polyester B: Intrinsic viscosity IV _B is 0.73 to 0.95 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at the time of temperature increase measured by DSC is 140 to 180 ° C., and crystallization temperature at the time of temperature decrease is 160 to Polyester at 200 ° C.

  Here, the crystallization temperature at the time of temperature rise and the crystallization temperature at the time of temperature fall of the polyester constituting the present invention are values obtained by a DSC measurement method described later on a molded plate (2 mm thickness) obtained by injection molding these polyesters at 290 ° C. It is.

  Moreover, the said polyester composition can be shape | molded and it can be set as a polyester molded object.

  Furthermore, the polyester molded body is selected from a preform for a hollow molded body, a sheet-shaped preform, or a stretched film formed by stretching these preforms in at least one direction or a stretch blow hollow molded body. Can be either.

  The polyester composition of the present invention suppresses the generation amount of aldehydes such as acetaldehyde and the generation amount of cyclic ester oligomer at the time of molding, retains transparency even by molding at a lower temperature, and has less fluctuation in transparency, Moreover, when it is set as a molded object, the molded object excellent in the mechanical characteristic can be given. In addition, since the polyester composition of the present invention has improved moldability at a lower temperature than the conventional one, there is less distortion during molding, and a molded body excellent in heat-resistant dimensional stability, particularly a hollow molded product, can be efficiently obtained by high-speed molding. A molded body that can be produced and has good pressure resistance and heat-resistant dimensional stability can be provided. Moreover, the polyester composition excellent in the long-time continuous moldability which does not stain a metal mold | die at the time of shaping | molding, and a molded object consisting thereof are provided. The polyester composition of the present invention can meet high required quality in the field of containers, sheets and the like.

  Hereinafter, embodiments of the polyester composition of the present invention and a molded article comprising the same will be described in detail.

The polyester composition of the present invention is a polyester composition containing, as a main component, at least two kinds of polyesters mainly composed of ethylene arylate, wherein the intrinsic viscosity of the polyester is 0.60 deciliter / gram or more, The difference is 0.05 to 0.25 deciliter / gram, the difference in the crystallization temperature when the polyester cools is within 20 ° C., and the content of the atoms used as the polycondensation catalyst in the polyester composition is as follows: The following expression (1) is satisfied.
1 ≦ (A / 25) + (B / 5) + (C / 3) + D ≦ 15 (1)
(In the formula, A, B, C, and D represent the antimony atom content, germanium atom content, aluminum atom content, and titanium atom content, respectively, in the polyester composition. The unit is ppm)

  Here, the polyester composition of the present invention can contain at least one selected from the above catalysts as a polycondensation catalyst within a range satisfying the above formula (1), and these catalysts can be contained in the above formula (1). ) Can be contained in an appropriate combination within a range that satisfies the above.

  The polyester composition of the present invention is a polyester composition that can be molded at a lower temperature than conventional because the fluidity at the time of melting in an extruder is improved by the action of a lower molecular weight polyester component, The resulting molded product can be reduced in the content of aldehydes such as acetaldehyde and improved in transparency. At the same time, since the orientation during heating and stretching is improved, it is possible to give a stretched molded article having excellent mechanical properties such as elastic modulus and tensile strength and excellent heat fixability. It can be beneficially used as a stretched hollow container excellent in pressure.

  The difference in intrinsic viscosity of the polyester constituting the polyester composition of the present invention is preferably 0.06 to 0.23 deciliter / gram, more preferably 0.07 to 0.21 deciliter / gram, particularly preferably 0.10. ~ 0.20 deciliter / gram. When the above intrinsic viscosity difference is less than 0.05 deciliter / gram, the effect of the low molecular weight component is lost, so the transparency of the molded article is deteriorated. On the other hand, under the molding temperature condition where the transparency of the molded article is good. The content of aldehydes such as acetaldehyde cannot be reduced, and flavor retention cannot be improved. On the other hand, when the above-mentioned intrinsic viscosity difference exceeds 0.25 deciliter / gram, thickness irregularities, whitened flow patterns, and the like occur in the obtained molded product, resulting in a problem of poor transparency. Here, when the polyester composition of the present invention comprises two or more kinds of polyesters, the difference in intrinsic viscosity is the difference in intrinsic viscosity between the maximum polyester and the minimum polyester with respect to the intrinsic viscosity.

  Polyesters having different intrinsic viscosities used in the present invention are polyesters produced so that the difference in intrinsic viscosities falls within the scope of the present invention in the melt polycondensation reaction step or the subsequent solid phase polymerization reaction step, or These are polyesters obtained by contact treatment with water under the condition that the intrinsic viscosity does not decrease.

  As other production methods for obtaining polyesters having different intrinsic viscosities, there are a method of hydrolyzing polyester by heat treatment with water at a high temperature, a method of melt treatment with an extruder, and the like. However, since the method by hydrolysis is carried out in a solid state, it is very difficult to control the degree of IV reduction, it is difficult to obtain polyester particles having a narrow IV fluctuation range, and particles after hydrolysis treatment Is likely to generate fine powder due to impact during transportation, etc., so there is a problem that the fluctuation of the transparency and crystallization speed of the molded body when using these becomes very large. The fluctuation is a big problem. Also, the method using the melt treatment has problems such as an influence on flavor retention and coloring due to an increase in aldehydes such as acetaldehyde during the treatment. Therefore, the polyester according to the present invention does not include polyester hydrolyzed by a method such as heat treatment under pressure with water or the like, or polyester melt-treated to reduce IV.

  Further, the difference in the crystallization temperature when the polyester constituting the polyester composition of the present invention falls is preferably within 18 ° C, more preferably within 15 ° C, and particularly preferably within 10 ° C. When the difference in the crystallization temperature when the temperature is lowered exceeds 20 ° C., the transparency of the obtained molded product is very poor. In addition, the intrinsic viscosity of the polyester affects the crystallization temperature at the time of temperature decrease. The higher the viscosity, the lower the crystallization temperature at the time of temperature decrease. However, the difference in the crystallization temperature at the time of temperature decrease is 2 ° C. within the range of the above intrinsic viscosity difference. That's it.

In the polyester composition of the present invention, since the low IV component acts as a plasticizer, the fluidity of the melt in the extruder is improved, so that the thermal conductivity is improved and the crystal nucleus melts even at a lower temperature. As a result, the melt has a slow crystallization rate. Further, since the difference in the crystallization temperature when the temperature falls between polyesters is within 20 ° C., crystallization is less likely to occur when the molded body is cooled from the melt. In addition, since fluidity is improved, local overheating is small and shearing heat generation is also kept low, so that not only the generation amount of aldehydes such as acetaldehyde is suppressed, but also aldehydes against the change in molding temperature. The change in the amount of generation is kept low.
The content of the atoms in the polyester composition of the present invention is preferably 2 ≦ (A / 25) + (B / 5) + (C / 3) + D ≦ 13.
More preferably
3 ≦ (A / 25) + (B / 5) + (C / 3) + D ≦ 12
Most preferably
5 ≦ (A / 25) + (B / 5) + (C / 3) + D ≦ 10
It is desirable to satisfy

  The type and content of the polycondensation catalyst in the composition affect the transesterification reaction between the polyesters used, but the content of the atoms derived from the polycondensation catalyst is in the range of the formula (1) Is less susceptible to transesterification between the polyesters during melt molding, and exhibits a fluidity-improving effect due to low molecular weight components, so that it can be molded at low temperatures and has excellent transparency and aldehyde content. A polyester molded body having a small content of cyclic ester oligomer can be obtained. If it is less than 1, it takes a very long time to produce the polyester, which is a problem in terms of economy. On the other hand, if it exceeds 15, the transesterification reaction between the polyesters occurs rapidly at the time of melting in the molding process, and the content of low molecular weight components is reduced. As a result, the effect of improving fluidity is lost and low temperature molding becomes impossible. . Further, the thermal decomposition is promoted by the catalyst, and the production of aldehydes and cyclic ester oligomers becomes violent, which is not preferable. In addition, the compound containing the said atom used as a polycondensation catalyst is demonstrated below.

  The compositions of these polyesters are preferably substantially the same. Here, “substantially the same” means that components exceeding 97 mol% of the acid components in each composition are preferably the same, more preferably 98 mol% or more, and particularly 98.5 mol% or more. Further, it is preferable that 95 mol% or more of the glycol components are the same, more preferably 97 mol% or more, and particularly preferably 98 mol% or more.

  Moreover, in this invention, when the polyester which comprises a polyester composition is 2 types, the structural ratio is 97 / 3-3 / 97 by weight ratio, Preferably it is 95 / 5-5 / 95, More preferably 90/10 to 10/90. Moreover, when it consists of 2 or more types of polyester, the composition ratio of polyester of the main component and other polyester is 95 / 5-5 / 95 by weight ratio, Preferably it is 93 / 7-7 / 93, More preferably 90/10 to 10/90.

Moreover, it is preferable that the relationship between the phosphorus atom content E and A, B, C, D in the polyester composition of the present invention satisfies the following formula (2).
0.1 ≦ {(A / 25) + (B / 5) + (C / 3) + D} / E ≦ 5 (2)
(In the formula, E represents the phosphorus atom content in the polyester composition. The unit is ppm)
The relationship between the phosphorus atom content E and A, B, C, D in the polyester composition of the present invention is as follows:
Preferably 0.2 ≦ {(A / 25) + (B / 5) + (C / 3) + D} /E≦4.5
More preferably
0.25 ≦ {(A / 25) + (B / 5) + (C / 3) + D} /E≦4.0
Most preferably
0.3 ≦ {(A / 25) + (B / 5) + (C / 3) + D} /E≦3.5
It is desirable to satisfy

  When the relationship between the phosphorus atom content E in the polyester composition and A, B, C, D is in the range of the formula (2), the transesterification reaction is unlikely to occur between the polyesters used during melt molding, Since the fluidity improving effect due to the molecular weight component is exhibited, it is possible to obtain a polyester molded article which can be molded at a low temperature, has good transparency, has a low aldehyde content, and a low cyclic ester oligomer content. If it exceeds 5, a transesterification reaction will occur between the polyesters during melt molding, and the effect of improving fluidity will be lost, and the hue and thermal stability of the polyester will be deteriorated. On the other hand, if the ratio is less than 0.1, the effect of the catalyst is reduced, so that it takes a very long time to produce the polyester, causing problems in terms of economy, and increasing the phosphorus compound content. Stability and hydrolytic stability are deteriorated, which is a problem. The phosphorus atom is derived from a phosphorus compound used as a stabilizer described below.

  Moreover, it is preferable that the terminal carboxyl group density | concentration with respect to the total number of terminal groups of each polyester which concerns on this invention is 5-40 equivalent%, Preferably it is 6-35 equivalent%, More preferably, it is 7-30 equivalent%. When trying to obtain a polyester having a terminal carboxyl group ratio of less than 5 equivalent% with respect to the total number of terminal groups, the solid phase polymerization time during the production of such a polyester becomes extremely long, resulting in a problem of economy. This is a problem because the occurrence of If the ratio of the terminal carboxyl group to the total number of terminal groups exceeds 40 equivalent%, the content of the cyclic ester oligomer in each polyester increases to 0.7% by weight or more, causing problems such as mold contamination as described below. Estimated that the effect of improving fluidity due to the contribution of low molecular weight components is lost because the transparency of the molded product deteriorates and the transesterification reaction between the polyesters used is promoted to cause rearrangement of the molecular weight distribution. As a result, the acetaldehyde content of the polyester molded body increases. A polyester having a terminal carboxyl group concentration that satisfies the above range can be obtained, for example, by appropriately adjusting the esterification conditions described later.

  The content of the cyclic ester oligomer in the polyester composition of the present invention is 70% or less, preferably 60% or less, more preferably 50% of the content of the cyclic ester oligomer contained in the melt polycondensation polyester prepolymer of the polyester. % Or less, particularly preferably 35% or less. Here, the polyester generally contains cyclic ester oligomers having various degrees of polymerization, but the cyclic ester oligomer referred to in the present invention is the cyclic ester oligomer having the largest content among the cyclic ester oligomers contained in the polyester. An ester oligomer means, for example, a cyclic trimer in the case of a polyester having ethylene terephthalate as a main repeating unit.

  In the case of PET, in which the polyester is a typical polyester having ethylene terephthalate as the main structural unit, the content of the cyclic trimer of the melt polycondensed polyester prepolymer is about 1.0% by weight. The content of the cyclic trimer in the composition 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 or less. Is preferred. The lower limit of the cyclic trimer content is 0.25% by weight or more, preferably 0.28% by weight or more, and more preferably 0.30% by weight or more from the viewpoint of economical production. In the case of molding a heat-resistant hollow molded article or the like from the polyester composition of the present invention, heat treatment is performed in a heating mold, but when the cyclic trimer content is 0.70% by weight or more, The adhesion of the oligomer to the surface of the heating mold increases rapidly, and the transparency of the obtained hollow molded article is very deteriorated.

  The ratio of the average weight (W) and the average weight (W) of each polyester chip according to the present invention is preferably 7 to 45 mg and 1.00 to 1.28, more preferably 10 to 40 mg and 1 respectively. 0.00-1.25, most preferably 15-30 mg and 1.00-1.20.

  When the average weight of the chips exceeds 50 mg, it takes a long time to melt in the molding machine, which is a problem because the content of aldehydes such as acetaldehyde in the polyester molded product is extremely increased. However, there is an economical problem that the speed is very slow, and an economical problem that a drying time becomes long when the polyester composition having a moisture content of about 2000 ppm or more is dried. In addition, in the case of a chip having an average weight of less than 5 mg, fine powder is very likely to be generated during chip handling, and sometimes exceeds 5000 ppm. Therefore, when the transparency of the polyester stretched hollow molded article is deteriorated as described above, In addition, when stored in the atmosphere, the moisture absorption rate is fast and becomes 2000 ppm or more in a short time, and it takes time to re-dry.

  On the other hand, if the ratio of the average weight (W) exceeds 1.30, it becomes difficult to melt at the time of molding, and low temperature molding becomes difficult. In particular, when used for a heat-resistant hollow stretch molded article, if the ratio is out of the range of 1.00 to 1.15, the effect of reducing aldehydes such as acetaldehyde and improving the transparency deteriorates. The blending amount of the polyester is likely to occur, which is not preferable because it causes transparency and thickness unevenness of the stretched hollow molded article of polyester.

  As a method for obtaining a chip having an average weight (W) and average weight (W) ratio within the range of the present invention, for example, the size of the hole of the extrusion die in the chip forming step described later, the chip forming conditions, etc. are appropriately changed. A method can be mentioned.

  The polyester according to the present invention is a polyester mainly containing ethylene arylate as a main repeating unit, but is preferably a linear polyester containing 70 mol% or more of ethylene arylate units, more preferably 85 mol% or more, particularly preferably 95. It is a linear polyester containing at least%.

Examples of the aromatic dicarboxylic acid component constituting the polyester according to the present invention include aromatic dicarboxylic acids such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. And functional derivatives.
Examples of the dicarboxylic acid used as a copolymerization component when the polyester is a copolymer include isophthalic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and 4,4′-diphenyl ether dicarboxylic acid. , Aromatic dicarboxylic acids such as 4,4′-diphenyl ketone dicarboxylic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, Examples thereof include aliphatic dicarboxylic acids such as glutaric acid and dimer acid and functional derivatives thereof, and alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid, and functional derivatives thereof.

  The glycol as a copolymerization component used when the polyester is a copolymer is diethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene. Glycols, 2-ethyl-2-butyl-1,3-propanediol, aliphatic glycols such as neopentyl glycol, dimer glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol 1,4-cyclohexane dimethylol, 2,5-norbornane dimethylol and the like alicyclic glycols, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-β-hydroxyeth Cyclophenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, aromatic glycols such as alkylene oxide adducts of bisphenol A, polyalkylene glycols such as polyethylene glycol and polybutylene glycol Etc.

  Furthermore, examples of the polyfunctional compound as a copolymer component used when the polyester is a copolymer include trimellitic acid, pyromellitic acid, and the like as an acid component, and glycerin and pentane as glycol components. Mention may be made of erythritol. The amount of copolymerization component used should be such that the polyester remains substantially linear. Monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized.

  A preferred example of the polyester according to the present invention is a polyester whose main structural unit is composed of ethylene terephthalate, more preferably 70 mol% or more of ethylene terephthalate units, and isophthalic acid, 1,4-cyclohexanedi, as a copolymerization component. A copolyester containing methanol or the like, particularly preferably a polyester containing 95 mol% or more of ethylene terephthalate units.

  Examples of these polyesters include polyethylene terephthalate (hereinafter abbreviated as PET), poly (ethylene terephthalate-ethylene isophthalate) copolymer, poly (ethylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly ( Examples thereof include an ethylene terephthalate-dioxyethylene terephthalate) copolymer, a poly (ethylene terephthalate-1,3-propylene terephthalate) copolymer, and a poly (ethylene terephthalate-ethylene cyclohexylene dicarboxylate) copolymer.

  Further, another preferred example of the polyester according to the present invention is a thermoplastic polyester whose main structural unit is composed of ethylene-2,6-naphthalate, and more preferably 70 mol% of ethylene-2,6-naphthalate unit. The thermoplastic polyester containing the above is preferable, and a thermoplastic polyester containing 90 mol% or more of ethylene-2,6-naphthalate units is particularly preferable.

  Examples of these thermoplastic polyesters include polyethylene-2,6-naphthalate (PEN), poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, poly (ethylene-2,6-naphthalate-ethylene isophthalate). ) Copolymer, poly (ethylene-2,6-naphthalate-dioxyethylene-2,6-naphthalate) copolymer, and the like.

Further, when the polyester composition is a polyester composition having ethylene terephthalate as a main repeating unit, it contains the following polyester A and polyester B as main components, It is preferable that the difference with the crystallization temperature at the time of temperature rising of polyester B is within 10 degreeC.
Polyester A: Intrinsic Viscosity IV _A is 0.60 to 0.80 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at temperature increase measured by DSC is 140 to 180 ° C., and crystallization temperature at temperature decrease is 160 to 160 ° C. Polyester at 200 ° C.
Polyester B: Intrinsic viscosity IV _B is 0.73 to 0.95 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at the time of temperature increase measured by DSC is 140 to 180 ° C., and crystallization temperature at the time of temperature decrease is 160 to Polyester at 200 ° C.

  Further, as polyester A or polyester B, at least one kind of each polyester that falls within the above characteristic range is used, for example, polyester A uses two kinds of polyesters that differ only in IV, and polyester B uses a kind of polyester. It is also possible to use polyester mixed so as to have the above-mentioned constitution ratio.

  Here, the crystallization temperature at the time of temperature rise and the crystallization temperature at the time of temperature fall of the polyester constituting the present invention are values obtained by the following DSC measurement method on a molded plate (2 mm thickness) obtained by injection molding these polyesters at 290 ° C. It is.

The difference between the crystallization temperature of polyester A when it is raised and the crystallization temperature of polyester B when it is raised is preferably within 8 ° C, more preferably within 7 ° C, and particularly preferably within 5 ° C.
When the difference in the crystallization temperature at the time of temperature increase exceeds 10 ° C., the crystallization speed fluctuation of the obtained molded product becomes large. As a result, for example, the variation in crystallinity of the heat-crystallized hollow molded body plug portion is large, resulting in large dimensional variation of the plug portion, resulting in poor capping properties and leakage of contents. Here, when the polyester composition of the present invention comprises two or more kinds of polyesters, the difference in the crystallization temperature at the time of temperature increase is the value of the polyester having the highest temperature crystallization temperature and the value at the lowest temperature increase. It represents the difference in the values of polyesters with crystallization temperatures.

The intrinsic viscosity IV _A of polyester A is preferably 0.63 to 0.78 deciliter / gram, more preferably 0.65 to 0.75 deciliter / gram, and the acetaldehyde content is preferably 6 ppm or less, more preferably 4 ppm. Hereinafter, particularly preferably 3 ppm or less, the crystallization temperature at the time of temperature rise is preferably 145 to 178 ° C., more preferably 150 to 175 ° C., and the crystallization temperature at the time of temperature drop is preferably 162 to 195 ° C., more preferably 165 to 165 ° C. 190 ° C. If the intrinsic viscosity IV _A of the polyester A is less than 0.60 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.80 deciliter / gram, the effect of reducing acetaldehyde is reduced. In addition, when the acetaldehyde content exceeds 10 ppm, the flavor retention of the obtained molded article is deteriorated, which is a problem. On the other hand, the economically profitable method has a limit of 1 ppm or less. Further, when the crystallization temperature at the time of temperature rise of polyester A is less than 140 ° C., the transparency of the molded article is deteriorated, and when it exceeds 180 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated. . When the crystallization temperature of polyester A during cooling is less than 160 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated, and when it exceeds 200 ° C., the transparency of the molded article is deteriorated.

The intrinsic viscosity IV _B of polyester B is preferably 0.74 to 0.90 deciliter / gram, more preferably 0.75 to 0.85 deciliter / gram, and the acetaldehyde content is preferably 6 ppm or less, more preferably 4 ppm. In the following, particularly preferably 3 ppm or less, the crystallization temperature during temperature rise is preferably 145 to 178 ° C, more preferably 150 to 175 ° C, and the crystallization temperature during temperature drop is preferably 162 to 195 ° C, more preferably 165 to 165 ° C. 190 ° C. The intrinsic viscosity of the polyester B IV _B If there is less than 0.73 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.95 deciliter / gram, heat generation during molding becomes intense, and the effect of reducing acetaldehyde becomes low. In addition, when the acetaldehyde content exceeds 10 ppm, the flavor retention of the obtained molded article is deteriorated, which is a problem. On the other hand, the economically profitable method has a limit of 1 ppm or less. Moreover, when the crystallization temperature at the time of temperature rise of polyester B is less than 140 ° C., the transparency of the molded product is deteriorated, and when it exceeds 180 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated. . When the crystallization temperature of polyester B during cooling is less than 160 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated, and when it exceeds 200 ° C., the transparency of the molded article is deteriorated.

  When the polyester according to the present invention is a polyester whose main repeating unit is ethylene-2,6-naphthalate (hereinafter sometimes abbreviated as PEN), the intrinsic viscosity of at least two polyesters is 0. Selected from polyesters in the range of 41-0.80 deciliters / gram, preferably 0.42-0.75 deciliters / gram, more preferably 0.45-0.70 deciliters / gram. When the IV is less than 0.41 deciliter / gram, the mechanical properties of the obtained molded article are poor. In addition, when it exceeds 0.80 deciliter / gram, it becomes necessary to increase the resin temperature at the time of melting by a molding machine or the like, and this is accompanied by thermal decomposition, increasing the number of aldehydes such as acetaldehyde, and the molded product becomes yellow. Problems such as coloring occur.

Furthermore, when the polyester according to the present invention is PEN, it contains the following polyester C and polyester D as main components, and the difference between the crystallization temperature of polyester C when heated and the crystallization temperature of polyester D when heated Is preferably a polyester composition having a temperature within 10 ° C.
Polyester C: Polyester having an intrinsic viscosity IV _C of 0.41 to 0.70 deciliter / gram, a crystallization temperature when measured by DSC of 180 to 235 ° C., and a crystallization temperature of 160 to 210 ° C. when decreasing.
Polyester D: Polyester having an intrinsic viscosity IV _D of 0.50 to 0.80 deciliter / gram, a crystallization temperature when measured by DSC of 180 to 235 ° C., and a crystallization temperature of 160 to 210 ° C. when decreasing.

The polyester according to the present invention can basically be produced by a conventionally known melt polycondensation method or melt polycondensation method-solid phase polymerization method. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. These may be composed of batch reactors or may be composed of continuous reactors. Further, the melt polycondensation step and the solid phase polymerization step may be operated continuously or may be operated separately. Hereinafter, an example of a preferable continuous production method for the polyester composition of the present invention will be described using polyethylene terephthalate (PET) as an example, but the present invention is not limited thereto. That is, a direct esterification method in which terephthalic acid, ethylene glycol, and if necessary, other copolymerization components are directly reacted and esterified while distilling off water, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst, Or transesterification method in which dimethyl terephthalate, ethylene glycol and other copolymerization components are reacted if necessary and transesterified while distilling off methyl alcohol, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst. Manufactured by. Next, when the intrinsic viscosity is increased, or when a low acetaldehyde content or a low cyclic trimer content is used, such as a heat-resistant container for low flavor beverages or an inner film of a beverage metal can, The resulting melt polycondensed polyester is subsequently subjected to solid state polymerization.
First, when a low polymer is produced by an esterification reaction, 1.02 to 2.0 mol, preferably 1.03 to 1.4 mol of ethylene glycol is added to 1 mol of terephthalic acid or an ester derivative thereof. The contained slurry is prepared and continuously supplied to the esterification reaction step.

In the esterification reaction, water or alcohol produced by the reaction is removed out of the system by a rectification column under the condition that ethylene glycol is refluxed using a multistage apparatus in which at least two esterification reactors are connected in series. While implementing. The temperature of the first stage esterification reaction is 240 to 270 ° C., preferably 245 to 265 ° C., and the pressure is 0.2 to 3 kg / cm ² G, preferably 0.5 to ² kg / cm ² G. The temperature of the esterification reaction in the final stage is usually 250 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.3 kg / cm ² G. . When carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are conditions between the reaction conditions for the first stage and the reaction conditions for the final stage. The increase in the reaction rate of these esterification reactions is preferably distributed smoothly at each stage. Ultimately, it is desirable that the esterification reaction rate reaches 90% or more, preferably 93% or more. By these esterification reactions, low-order condensates having a molecular weight of about 500 to 5,000 are obtained.

  When terephthalic acid is used as a raw material, the esterification reaction can be carried out without a catalyst by the catalytic action of terephthalic acid as an acid, but may be carried out in the presence of a polycondensation catalyst.

  Also, tertiary amines such as triethylamine, tri-n-butylamine, benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, and lithium carbonate When a small amount of a basic compound such as sodium carbonate, potassium carbonate or sodium acetate is added, the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate is relatively low (5% relative to all diol components). Mol% or less).

  Next, in the case of producing a low polymer by transesterification, 1.1 to 2.0 mol, preferably 1.2 to 1.5 mol of ethylene glycol was contained with respect to 1 mol of dimethyl terephthalate. The solution is prepared and continuously fed to the transesterification step.

  The transesterification reaction is carried out while removing methanol generated by the reaction outside the system using a rectification column under the condition that ethylene glycol is distilled back using an apparatus in which 1 to 2 transesterification reactors are connected in series. To do. The temperature of the first stage transesterification is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the transesterification reaction in the final stage is usually 230 to 270 ° C., preferably 240 to 265 ° C., and as the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Co, Ca, Ba, carbonates Alternatively, Pb, Zn, Sb, Ge oxide or the like is used. A low-order condensate having a molecular weight of about 200 to 500 is obtained by these transesterification reactions.

  Dimethyl terephthalate, terephthalic acid or ethylene glycol, which is the starting material, includes virgin dimethyl terephthalate derived from para-xylene, ethylene glycol derived from terephthalic acid or ethylene, as well as methanol decomposition from used PET bottles. A recovered raw material such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered by a chemical recycling method such as decomposition of ethylene glycol or ethylene glycol can also be used as at least a part of the starting material. Needless to say, the quality of the recovered raw material must be refined to a purity and quality suitable for the intended use.

  Subsequently, the obtained low-order condensate is supplied to a multistage liquid phase condensation polymerization process. The polycondensation reaction conditions are as follows: the first stage polycondensation reaction temperature is 250 to 290 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 Torr, preferably 200 to 30 Torr. The temperature is 265 to 300 ° C., preferably 275 to 295 ° C., and the pressure is 10 to 0.1 Torr, preferably 5 to 0.5 Torr. When carried out in three or more stages, the reaction conditions for the intermediate stage polycondensation reaction are conditions between the reaction conditions for the first stage and the reaction conditions for the last stage. The degree of increase in intrinsic viscosity achieved in each of these polycondensation reaction steps is preferably distributed smoothly. A single-stage polycondensation apparatus may be used for the polycondensation reaction.

  The polycondensation reaction is performed using a polycondensation catalyst. As the polycondensation catalyst, at least one compound selected from Ge, Sb, Ti, or Al compounds is preferably used. In the polyester composition of the present invention, the metal atom content from these compounds needs to be in a specific range that satisfies the above formula (1). These compounds are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries and the like.

  As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or ethylene glycol slurry, a solution in which crystalline germanium dioxide is heated and dissolved in water, or a solution in which ethylene glycol is added and heat-treated are used. In particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water or a solution in which ethylene glycol is added and heated. In addition, compounds such as germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite can also be used. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used alone, the amount used is preferably 5 to 75 ppm, more preferably 10 to 70 ppm, and still more preferably 15 to 60 ppm as the residual amount of Ge in the polyester.

  Ti compounds include tetraethyl titanates, tetraisopropyl titanates, tetra-n-propyl titanates, tetraalkyl titanates such as tetra-n-butyl titanates and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl oxalate compounds such as titanium strontium oxalate, titanium trimellitate, titanium sulfate, titanium chloride, titanium halide hydrolyzate, titanium oxalate, titanium fluoride, titanium hexafluoride Titanium complex with potassium acid, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium acetylacetonate, hydroxy polyvalent carboxylic acid or nitrogen-containing polyvalent carboxylic acid Products, composite oxides composed of titanium and silicon or zirconium, reaction products of titanium alkoxide and phosphorus compound, reaction products of titanium alkoxide and aromatic polycarboxylic acid or acid anhydride thereof with specific phosphorus compound Etc. When the Ti compound is used alone, it is added so that the residual amount of Ti in the produced polymer is 0.1 to 50 ppm, preferably 0.5 to 10 ppm.

  Examples of the Sb compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. When the Sb compound is used alone, it is added so that the residual amount of Sb in the produced polymer is 50 to 400 ppm, preferably 50 to 300 ppm, preferably 50 to 200 ppm, and more preferably 50 to 180 ppm.

  Al compounds include aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum carbonate, aluminum phosphate, aluminum phosphonate and other inorganic acid salts, aluminum n-propoxide, aluminum iso-propoxide Aluminum alkoxides such as aluminum n-butoxide and aluminum t-butoxide, aluminum chelate compounds such as aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum, etc. Organoaluminum compounds and their partial hydrolysates, aluminum oxide, etc. And the like. Of these, aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred. When the Al compound is used alone, it is added so that the residual amount of Al in the produced polymer is in the range of 5 to 100 ppm, preferably 10 to 50 ppm.

  In the production of the polyester according to the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination as necessary. The alkali metal or alkaline earth metal is preferably at least one selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba, and the use of an alkali metal or a compound thereof is more preferable. preferable. When using an alkali metal or a compound thereof, use of Li, Na, K is particularly preferable. Examples of the alkali metal and alkaline earth metal compounds include saturated aliphatic carboxylates such as formic acid, acetic acid, propionic acid, butyric acid, and succinic acid, and unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid. , Aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, hydroxycarboxylates such as lactic acid, citric acid and salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, phosphorus Inorganic acid salts such as acid hydrogen, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid and bromic acid, and organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid , Organic sulfates such as lauryl sulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butyl Alkoxides such as alkoxy, chelate compounds and the like acetylacetonate, hydrides, oxides, and hydroxides and the like.

  The alkali metal compound or alkaline earth metal compound is added to the reaction system as a powder, an aqueous solution, an ethylene glycol solution, or 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.

  Furthermore, the polyester according to the present invention is at least one element selected from the group consisting of silicon, manganese, iron, cobalt, zinc, gallium, strontium, zirconium, niobium, molybdenum, indium, tin, hafnium, thallium, tungsten. You may contain the metal compound containing. These metal compounds include saturated aliphatic carboxylates such as acetates of these elements, unsaturated aliphatic carboxylates such as acrylates, aromatic carboxylates such as benzoic acid, and halogens such as trichloroacetic acid. Hydroxycarboxylates such as carboxylates and lactates, inorganic acid salts such as carbonates, organic sulfonates such as 1-propanesulfonate, organic sulfates such as lauryl sulfate, oxides, hydroxides, chlorides Products, alkoxides, acetylacetonates and the like, and are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries and the like. These metal compounds are added so that the residual amount of elements of these metal compounds per ton of the produced polymer is in the range of 0.05 to 3.0 mol. These metal compounds can be added at any stage of the polyester formation reaction step.

  Also, as stabilizers, phosphoric acid, phosphoric acid esters such as polyphosphoric acid and trimethyl phosphate, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, phosphine compounds It is preferable to use at least one phosphorus compound selected from the group consisting of: 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, phenylphosphonic acid Diphenyl ester and the like.

  These stabilizers can be added in any step from the slurry preparation tank of terephthalic acid and ethylene glycol to the molding step. In the polyester composition of the present invention, it is necessary that the phosphorus atom content from the phosphorus compound be in a specific range that satisfies the formula (2). The P compound is added so that the residual amount of P in the produced polymer is preferably in the range of 1 to 100 ppm.

  When an Al compound is used as the polycondensation catalyst, it is preferably used in combination with a phosphorus compound, and is preferably used as a solution or slurry in which an aluminum compound and a phosphorus compound are previously mixed in a solvent. In the case of an Al compound, a more preferable phosphorus compound is at least one selected from the group consisting of phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. It is a phosphorus compound. By using these phosphorus compounds, an effect of improving the catalytic activity is seen, and an effect of improving physical properties such as thermal stability of the polyester is seen. Among these, use of a phosphonic acid compound is preferable because of its great effect of improving physical properties and improving catalytic activity. Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  The melt polycondensed polyester obtained as described above has a chemical oxygen demand (hereinafter abbreviated as COD) from the pores after completion of the melt polycondensation, preferably 2.0 mg / l or less, more preferably. A method of extruding into cooling water of 1.5 mg / l or less, more preferably 1.0 mg / l or less and cutting in water, or after extruding into the air, immediately cooling with cooling water having the same COD value as above. Depending on the cutting method, chips are formed into columnar, spherical, angular, or plate-like forms. The lower limit of COD is not particularly limited. However, in practical terms, it is 0.01 mg / l, and if it is less than 0.01 mg / l, the equipment cost increases and economical chip formation is not possible. It may be possible.

  In order to reduce the COD of new water to be introduced into the chip forming process, an apparatus for reducing the COD of water at least at one point in the process until industrial water is sent to the chip forming process to supply the chip forming process. Install. Furthermore, an apparatus for reducing COD may be installed in at least one place in the process until the water discharged from the chip forming process is returned to the chip forming process again. Examples of the apparatus for reducing COD include ultrafiltration, reverse osmosis filtration, coagulation sedimentation, activated sludge treatment, activated carbon treatment, and ultraviolet irradiation.

Further, it is more preferable to chip the melt polycondensed polyester by using at least one of the following (3) to (6), more preferably cooling water satisfying all as cooling water at the time of chip formation. preferable.
Na ≦ 1.0 (ppm) (3)
Mg ≦ 1.0 (ppm) (4)
Si ≦ 2.0 (ppm) (5)
Ca ≦ 1.0 (ppm) (6)

  The sodium content (Na) in the cooling water is preferably Na ≦ 0.5 ppm, more preferably Na ≦ 0.1 ppm. The magnesium content (Mg) in the cooling water is preferably Mg ≦ 0.5 ppm, more preferably Mg ≦ 0.1 ppm. Further, the content (Si) of silicon in the cooling water is preferably Si ≦ 0.5 ppm, more preferably Si ≦ 0.3 ppm. Furthermore, the calcium content (Ca) in the cooling water is preferably Ca ≦ 0.5 ppm, and more preferably Ca ≦ 0.1 ppm.

  In order to reduce sodium, magnesium, calcium, and silicon in the cooling water, an apparatus for removing sodium, magnesium, calcium, and silicon is installed in at least one place until the industrial water is sent to the chip cooling process. Also, a filter is installed to remove clay minerals such as silicon dioxide and aluminosilicate particles. Examples of the device for removing sodium, magnesium, calcium, and silicon include an ion exchange device, an ultrafiltration device, and a reverse osmosis membrane device.

  Next, the previous melt polycondensed polyester chip is preferably pre-crystallized in a continuous crystallization apparatus having two or more stages in an inert gas atmosphere. For example, in the case of PET, the temperature of 100 to 180 ° C. is 1 minute to 5 hours in the first stage precrystallization, and then the temperature of 160 to 210 ° C. is 1 minute to 3 hours in the second stage precrystallization. In the pre-crystallization of the second and higher stages, it is preferable to perform crystallization step by step at a temperature of 180 to 210 ° C. for 1 minute to 3 hours. The crystallinity of the chip after crystallization is preferably in the range of 30 to 65%, preferably 35 to 63%, and more preferably 40 to 60%. The crystallinity can be obtained from the density of the chip.

  Next, solid phase polymerization is performed in an inert gas atmosphere or under reduced pressure at a temperature optimum for the prepolymer so that the increase in intrinsic viscosity due to solid phase polymerization is 0.10 deciliter / gram or more. For example, in the case of PET, the upper limit of the solid phase polymerization temperature is preferably 215 ° C. or lower, more preferably 210 ° C. or lower, particularly 208 ° C. or lower, and the lower limit is 190 ° C. or higher, preferably 195 ° C. or higher. is there.

  It is preferable to set the chip temperature to about 70 ° C. or less, preferably 60 ° C. or less, more preferably 50 ° C. or less within about 30 minutes, preferably within 20 minutes, more preferably within 10 minutes after completion of the solid phase polymerization.

  As described above, the shape of the polyester chip according to 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 diameter is usually 1.0 to 5.0 mm, preferably 1.0 to 4.0 mm, and more preferably 1.0 to 3.0 mm.

  The polyester according to the present invention can be produced by appropriately controlling the type and amount of polycondensation catalyst, melt polycondensation, solid phase polymerization conditions, and the like. It can also be obtained by a method of giving an impact to the polyester chip thus obtained, and a method of blending a polyolefin resin, particularly polyethylene, polyamide resin, polyoxymethylene resin, etc. as described below.

  In addition, the amount of diethylene glycol copolymerized with the polyester according to the present invention, particularly the polyester in which the main repeating unit is composed of ethylene terephthalate, is 1.0 to 5.0 mol% of the glycol component constituting the polyester. , Preferably it is 1.3-4.5 mol%, More preferably, it is 1.5-4.0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, and the decrease in molecular weight becomes large at the time of molding, and the increase in acetaldehyde content and formaldehyde content becomes large, which is not preferable. On the other hand, when the diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.

  In addition, the content of aldehydes such as acetaldehyde in the polyester according to the present invention is 50 ppm or less, preferably 30 ppm or less, more preferably 10 ppm or less. When the aldehyde content exceeds 50 ppm, the effect of maintaining the flavor of contents such as a molded article molded from the polyester composition is deteriorated. Further, these lower limits are preferably 0.1 ppb from the viewpoint of production. In particular, when a polyester having ethylene terephthalate as a main repeating unit as a polyester composition of the present invention is used as a material for a container for low flavor beverages such as mineral water, acetaldehyde of each of the above polyesters The content is desirably 10 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, and most preferably 4 ppm or less.

  Further, at least one of the sodium content, calcium content, and silicon content of the polyester according to the present invention is 3 ppm or less, preferably 1 ppm or less, more preferably 0.5 ppm or less, and further preferably 0.3 ppm or less. Particularly preferably, it is desirable to be 0.1 ppm or less. When the content of at least one of the sodium content, calcium content, and silicon content exceeds 3 ppm, the crystallization speed increases, and the plug portion of the thick hollow molding preform is crystallized. For this reason, the amount of shrinkage of the plug part does not fall within the specified value range, so that the capping part of the plug part is defective and the contents leak, and the preform for hollow molding is whitened. Stretching is impossible. Further, when a polyester composition having a moisture content of 2000 ppm or more is dried with dehumidified air of 130 ° C. or more, the COD exceeds 2.0 mg / l, and the conditions (3) to (6) are not satisfied. Polyester formed into a chip using cooling water is likely to be colored, the hue of the obtained molded product is deteriorated, and sometimes fluorescent light is emitted.

  Further, in the polyester composition of the present invention, the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less, preferably 0.3% by weight or less, more preferably 0.20. It is preferred that it is not more than wt%, most preferably not more than 0.1 wt%. When the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes exceeds 0.40% by weight, the amount of the cyclic ester oligomer increases when the resin for molding is melted, and during continuous molding, the oligomer on the surface of the heating mold is increased. -Adhesion increases rapidly, resulting in a problem that the transparency of the obtained molded body such as a hollow molded body is very deteriorated, and a problem that much labor and time are required for cleaning the mold. Moreover, the lower limit of the cyclic ester oligomer increase amount is about 0.01% by weight, and even if the lower limit is decreased below this, the economic effect on the above problems is very small. A polyester in which the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less can be produced by deactivating the polycondensation catalyst of the polyester obtained above. it can.

  Here, the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is the value obtained for the preform obtained by the molding method of (18) described in the following “Measurement Method” section. It is.

  Examples of the method for deactivating the polyester polycondensation catalyst include a method in which the polyester chip is contact-treated with water, water vapor or water vapor-containing gas.

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

  The water to be used is preferably water that satisfies at least one of the above (3) to (6), and more preferably water that satisfies all of (3) to (6).

  When the polyester chip and water vapor or water vapor-containing gas are contacted, the water vapor or water vapor containing gas or water vapor containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C., is preferably 1 kg of granular polyester. The water vapor is supplied in an amount of 0.5 g or more as water vapor, or is present to bring the granular polyester into contact with water vapor. The contact between the polyester chip and water vapor is usually performed for 10 minutes to 2 days, preferably 20 minutes to 10 hours. The processing method may be either a continuous method or a batch method.

  Further, as another means for deactivating the polycondensation catalyst, there is a method in which a phosphorus compound is blended with the polyester and mixed and reacted in a molten state such as during molding to deactivate the polycondensation catalyst.

  As a method of blending a phosphorous compound with polyester, a predetermined amount of phosphorous compound is polyester by a method of dry blending the phosphorous compound with the polyester or a method of mixing a polyester masterbatch chip in which a phosphorous compound is melt-kneaded and blended with a polyester chip. And a method of inactivating the polycondensation catalyst by melting in an extruder or a molding machine, a method of immersing chips in a phosphorus compound solution, particularly a phosphoric acid aqueous solution, and a method of adding as a master batch. These phosphorus compounds may be copolymerized with polyester.

  Examples of the phosphorus compound used include phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specific examples are the compounds described above, and these may be used alone or in combination of two or more.

  The fine content of each polyester constituting the polyester composition of the present invention is preferably 0.1 to 5000 ppm. The fine content is preferably 0.1 to 3000 ppm, more preferably 0.1 to 1000 ppm, further preferably 0.1 to 500 ppm, and most preferably 0.1 to 100 ppm. When the content of fine is less than 0.1 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded container becomes insufficient, so that the shrinkage amount of the plug portion is within the specified value range. It may not fit inside and may not be capped. When the content exceeds 5000 ppm, the variation in blending amount and blending amount of the polyester A and the polyester B is likely to occur, and as a result, the intrinsic viscosity variation of the molded body becomes large, and the crystallization speed and stretchability vary. Arise.

  Further, the difference between the melting point of the fine constituting the polyester composition of the present invention and the melting point of the chip is 15 ° C. or less, preferably 10 ° C. or less, more preferably 5 ° C. or less. In the case where the difference includes fines exceeding 15 ° C., the crystals are not completely melted under the normally used melt molding conditions and remain as crystal nuclei. For this reason, in the case of a hollow molded body, when the hollow molded body plug portion is heated, the crystallization speed becomes faster, so that the crystallization of the plug portion becomes excessive. As a result, since the amount of shrinkage of the plug portion does not fall within the specified value range, the capping portion of the plug portion becomes defective and the contents may leak. Moreover, the preform for hollow molding is whitened, and thus normal stretching is impossible, thickness unevenness occurs, and the transparency of the obtained hollow molded body is deteriorated due to the high crystallization speed. Variations in transparency are also significant. In the case of a sheet-like material, the obtained sheet-like material is poor in transparency and has a high crystallization speed, so that normal stretching is impossible, and only a stretched film having large thickness spots and poor transparency can be obtained. Absent.

  However, when trying to obtain a hollow molding preform or sheet-like material with good transparency and stretchability from a polyester composition containing a fine whose melting point of the fine and the melting point of the chip exceeds 15 ° C., It must be melt molded at a temperature about 25-50 ° C. or higher above the melting point of the polyester chip. However, at such a high temperature, the thermal decomposition of the polyester becomes intense, and a large amount of by-products such as acetaldehyde and formaldehyde are generated, which greatly affects the flavor of the contents of the resulting molded body. It becomes. Further, when the polyester composition of the present invention contains at least one resin selected from the group consisting of the following polyolefin resins, polyamide resins, and polyacetal resins, generally these resins are more suitable than the polyester according to the present invention. Since the thermal stability is often inferior, in high temperature molding as described above, it causes thermal decomposition and generates a large amount of by-products. Will be affected.

  When the polyester composition of the present invention is PET, a fine or film-like material having a melting point exceeding 265 ° C. becomes a problem.

  The polyester composition of the present invention can be obtained by using a polyester having the characteristics defined in the claims of the present invention and mixing them by a conventionally known method. Examples thereof include a method of dry blending the above polyester with a tumbler, V-type blender, Henschel mixer or the like.

  Furthermore, it is preferable that the polyester composition of the present invention contains 0.1 ppb to 5000 ppm of at least one resin selected from the group consisting of polyolefin resin, polyamide resin, and polyacetal resin. The blending ratio of the resin used in the present invention to the polyester is 0.1 ppb to 1000 ppm, preferably 0.3 ppb to 100 ppm, more preferably 0.5 ppb to 10 ppm, still more preferably 1.0 ppb to 1 ppm, particularly preferably. 1.0 ppb to 45 ppb. When the blending amount is less than 0.1 ppb, the crystallization speed becomes very slow and the crystallization of the plug portion of the hollow molded body becomes insufficient. Therefore, when the cycle time is shortened, the shrinkage amount of the plug portion is specified. Since it does not fall within the value range, it becomes a problem of capping failure. On the other hand, if it exceeds 5000 ppm, the crystallization speed will be high, and the crystallization of the plug part of the hollow molded body will be excessive, and the shrinkage amount of the plug part will not fall within the specified range, resulting in capping failure. Leakage of the product occurs, and the preform for the hollow molded body is whitened, so that normal stretching is impossible. Also, in the case of a sheet-like material, if it exceeds 5000 ppm, the transparency is very poor, and the stretchability is also poor and normal stretching is impossible, and only a stretched film with large thickness spots and poor transparency can be obtained. Absent.

  Examples of the polyolefin resin blended in the polyester composition of the present invention include a polyethylene resin, a polypropylene resin, and an α-olefin resin. These resins may be crystalline or amorphous. Production of the polyester composition blended with the polyolefin resin or the like in the present invention is a method of directly adding the resin such as the polyolefin resin to the polyester so that the content is in the above range, and melt-kneading, or In addition to conventional methods such as a method of adding as a master batch and melt-kneading, the resin is added to the polyester production stage, for example, during melt polycondensation, immediately after melt polycondensation, immediately after precrystallization, during solid phase polymerization, Either directly after the phase polymerization, or in the process from the end of the production stage to the molding stage, it can be added directly as a granular material, or the polyester chips can be placed under flow conditions. A method of mixing by a method such as bringing the resin member into contact or a method of melt-kneading after the contact treatment may also be used.

  Here, as a method of bringing the polyester chip into contact with the resin member under flow conditions, it is preferable that the polyester chip is brought into collision contact with the member within the space where the resin member is present. For example, immediately after the melt polycondensation of polyester, immediately after precrystallization, immediately after solid-phase polymerization, etc., at the time of filling and discharging the transport container in the transport stage as a product of polyester chips, etc. When the molding machine is inserted in the chip molding stage, a part of pneumatic transportation piping, gravity transportation piping, silo, magnet catcher magnet part, etc. is made of the resin, or the resin film, sheet, molded body, etc. Or lining the resin or installing the resin member such as a rod or net in the transfer path, etc. Te, and a method of transferring the polyester chips. The contact time of the polyester chip with the member is usually an extremely short time of about 0.01 seconds to several minutes, but a small amount of the resin can be mixed into the polyester.

  The polyester composition of the present invention can be blended with polyamide, a low molecular weight amino group-containing compound, and a hydroxyl group-containing compound as a trap for aldehyde compounds.

  When the polyester molded body from the polyester composition of the present invention is used as a container for a low flavor beverage such as mineral water, the acetaldehyde content and the formaldehyde content of the polyester molded body are 10 ppm or less and 3 ppm or less, respectively. Preferably they are 8 ppm or less and 2 ppm or less, More preferably, they are 7 ppm or less and 1 ppm or less.

The polyester molded body having a low aldehyde content such as acetaldehyde is, for example, 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, more preferably 100 parts by weight of the polyester composition. It can be obtained by using a polyester composition in which 1.0 to 2 parts by weight of a capture material for an aldehyde compound such as polyamide is blended.
Further, when it is desired to obtain a molded article having excellent gas barrier properties, transparency that does not impair practicality, and very low aldehyde content and excellent flavor retention, the polyester composition 100 is used. A polyester composition in which 3 to 30 parts by weight, preferably 5 to 10 parts by weight of polyamide is blended with parts by weight can be used.

  Examples of the polyamide to be blended in the polyester composition of the present invention as an aldehyde compound capturing material include at least one polyamide selected from aliphatic polyamide and partially aromatic polyamide.

  Preferred examples of the aliphatic polyamide used in the present invention include nylon 6, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 6/66, nylon 6/610, and the like. A preferred example of the partially aromatic polyamide is a structure derived from metaxylylenediamine or mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and an aliphatic dicarboxylic acid. Examples thereof include a metaxylylene group-containing polyamide containing units in a molecular chain of at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more.

  Further, the partially aromatic polyamide according to the present invention contains structural units derived from a polybasic carboxylic acid having 3 or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range. Also 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. % Or more, more preferably 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 preferable 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 aminocapron. At least one acid selected from aliphatic diamines and terephthalic acid or isophthalic acid obtained by using aminocarboxylic acids such as acids, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. as copolymerization components Is a polyamide containing in the molecular chain at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more.

  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.

  Moreover, it is preferable that the polyamide according to the present invention has a second-order transition point of the polyamide measured by DSC (differential scanning calorimeter) of 50 to 120 ° C. When the secondary transition point is less than 50 ° C., it is not preferable because it is fused at the time of drying process or extrusion with polyester or cannot be quantitatively extruded. Moreover, when exceeding 120 degreeC, when extending | stretching a polyester composition, it will not be stretched | uniformly uniformly but a thickness spot etc. will arise and it is unpreferable.

  In addition, the shape of the polyamide chip according to 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 diameter is usually 1.0 to 5 mm, preferably 1.2 to 4 mm, and more preferably 1.5 to 3 mm. Further, the average weight of the chips is practically in the range of 5 to 50 mg / piece, and the ratio of the average weight of the polyester chips constituting the polyester composition to be blended is in the range of 0.50 to 1.50. desirable.

  Examples of the low molecular weight amino group-containing compound include aliphatic amine compounds such as stearylamine, 1,8-diaminonaphthalate, 3,4-diaminobenzoic acid, 2-aminobenzamide, and 4,4′-diaminodiphenylmethane. And aromatic amine compounds such as melamine, triazine compounds such as benzoguanamine, and amino acids.

  Examples of the hydroxyl group-containing compound include polyvinyl alcohol, ethylene vinyl alcohol polymer, sugar alcohol, and trimethylolpropane.

  These polyamide compounds, low molecular weight amino group-containing compounds, or hydroxyl group-containing compounds may be used alone or in admixture at an appropriate ratio.

  Moreover, as a polyamide mix | blended with the polyester composition of this invention as a barrier improvement material, at least 1 type of polyamide chosen from the said partial aromatic polyamide can be used.

  As a method for blending the aldehyde compound capture material, various methods described above for the blending method of the polyolefin resin or the like blended for the purpose of improving crystallinity can be used.

  The polyester composition of the present invention can be preferably used as a hollow molded body, a packaging material such as a tray or a biaxially stretched film, a film for covering a metal can, or a fiber containing a monofilament. The polyester composition of the present invention can also be used as a single constituent layer such as a multilayer molded body or a multilayer film. It can also be used as a base material on which an oxygen barrier film such as carbon or silica is deposited.

  The method for producing a polyester molded body from the polyester composition of the present invention will be briefly described below by taking, as an example, a polyester composition containing, as a main component, a polyester having ethylene terephthalate as a main repeating unit, but is limited to this. It is not a thing. The polyester composition of the present invention is a film formed by a commonly used melt molding method after the moisture content is reduced to about 100 ppm or less, preferably 50 ppm or less by heat drying under reduced pressure or heat drying under an inert gas. A molded body to be a sheet, a container, or other packaging material can be molded. As conditions relating to the production of the preform, the molten resin temperature is 260 to 295 ° C., preferably 262 to 290 ° C., more preferably 265 by heating a barrel, a die, a hot runner or the like of an injection molding machine or an extrusion molding machine. It is important to set the temperature in a range of ˜285 ° C. Here, the molten resin temperature refers to a temperature obtained by immediately measuring, for example, a thermocouple thermometer with a resin injected or extruded from a nozzle tip or a die outlet of an injection molding machine or the like.

  In addition, the melt residence time in the molding machine can be set by arbitrarily selecting the shape of the extruder screw, L / D, etc., and the amount of extrusion in the case of extrusion molding, or in the case of injection molding. The cycle time, the metering stroke (screw back amount) and the like are arbitrarily set, and the time is set in the range of 10 to 500 seconds, preferably 20 to 300 seconds, and more preferably 30 to 200 seconds. Here, the melt residence time is a residence time in a state where the resin is melted in the molding machine. Specifically, the melt residence time is a time during which the resin is melted and held in a cylinder in the molding machine and in a hot runner or a die. That is.

In the case of injection molding, if the melt residence time is t, t is given by the following formula (7).
t = W × S / P (7)
here,
W: Weight of molten resin (g) in cylinders and hot runners of injection molding machines, etc.
S: Molding cycle time (seconds)
P: Molded product weight (g)

  In the present invention, by controlling the molten resin temperature in the range of 260 to 295 ° C. and setting the melt residence time in the range of 10 to 500 seconds, at least two kinds of polyesters mainly containing ethylene terephthalate as the main repeating unit From a polyester composition containing as a main component, the content of aldehydes such as acetaldehyde is low, the flavor retention is excellent, the transparency is excellent, and the transparent spots (for example, the whitened flow pattern or It is possible to obtain a preformed body such as a preform for a hollow molded body that is free from the occurrence of partial whitening or wrinkles and has no problem in the shape of the plug portion after crystallization. In particular, in the case of a wall-thickened molded article such as a bottle, these effects become significant.

  When the temperature of the molten resin is less than 260 ° C, the torque load of an injection molding machine or the like is large and molding becomes difficult, and the obtained preform becomes extremely poor in transparency, and the thickness of the sheet-like material varies. Becomes larger. Moreover, when the temperature exceeds 295 ° C., the thermal decomposition becomes severe and the content of aldehyde such as acetaldehyde increases, which is a problem. If the melt residence time is less than 10 seconds, the transparency of the preform is deteriorated due to insufficient melting, and if it exceeds 500 seconds, the transparency of the preform is very good, but aldehydes such as acetaldehyde As a result, the molding cycle becomes longer and the productivity of the preform is lowered.

  Here, the polyester composition containing a polyester having ethylene terephthalate as a main repeating unit as a main component has been described. However, the temperature of the molten resin when producing a preform from the polyester composition of the present invention is higher than the melting point of the constituent polyester. In addition, it is necessary to control the set temperature of a barrel of an injection molding machine or the like or a hot runner so as to be 10 to 45 ° C., preferably 10 to 40 ° C., more preferably 30 ° C.

  Here, the polyester preform is an unstretched sheet obtained by melt extrusion molding a polyester, a preform obtained by compression molding a melt mass obtained by melt extrusion molding, or injection molding. It is the preform etc. which are obtained.

Moreover, it is possible to improve mechanical strength by extending | stretching the sheet-like material which consists of a polyester composition of this invention at least to a uniaxial direction. The stretched film composed of the polyester composition of the present invention is a sheet-like material obtained by injection molding or extrusion molding, and can be any one of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching that are usually used for PET stretching. It is molded using a stretching method. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.
Below, the specific manufacturing method about the extending | stretching molded object in the case of PET is demonstrated easily.

  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 a stretched hollow molded body, a foam molded from the polyester 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 portion and the bottom portion are processed as they are, 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 300 ° 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, it is generally heat-set in a blow mold and heat resistant. 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 several seconds to several minutes, under tension by compressed air or the like.

  In addition, 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, or after the bottle is formed, The stopper is crystallized with the heater.

  The polyester composition of the present invention can also be used for the production of a stretched hollow molded body by a so-called compression molding method in which a preform obtained by compression molding a melt mass cut after melt extrusion is stretch blow molded. Can do.

  In the polyester composition of the present invention, known ultraviolet absorbers, antioxidants, oxygen scavengers, lubricants added from the outside, lubricants precipitated internally during the reaction, mold release agents, nucleating agents, stability Various additives such as an agent, an antistatic agent, a bluing agent, a dye, and a pigment may be blended.

  In addition, when the polyester composition of the present invention is used for a film, in order to improve handling properties such as slipping property, winding property, and blocking resistance, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid are included in the polyester. Inorganic particles such as calcium, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, organic salt particles such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, terephthalate, divinylbenzene, styrene, acrylic acid, Inactive particles such as crosslinked polymer particles such as methacrylic acid, acrylic acid or a vinyl monomer of methacrylic acid alone or as a copolymer can be contained.

  The main characteristic value measuring methods in the present invention will be described below.

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

(1) Intrinsic viscosity of polyester (IV)
It calculated | required from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent. The IV of the polyester composition was a weighted average value calculated from the IV of the constituent polyester.

(2) Polyethylene glycol content of polyester (hereinafter referred to as [DEG content])
Decomposition with methanol, the amount of DEG was quantified by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.

(3) Polyester cyclic trimer content (hereinafter referred to as “CT content”)
300 mg of the frozen and ground 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, the volume was adjusted to 10 mL with dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

(4) Increasing amount of cyclic trimer at the time of melting polyester (△ CT amount)
After cutting out a strip of about 1 to 3 mm in size from the mouth of the preform molded in the following (18) and then drying it, 3 g of this polyester sample was placed in a glass test tube and 290 in a nitrogen atmosphere. Immerse in an oil bath at 60 ° C. for 60 minutes to melt. The amount of increase in cyclic trimer at the time of melting is determined by the following equation.
Increase in cyclic trimer during melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content (wt%) of the preform before melting

(5) Acetaldehyde content of polyester (hereinafter referred to as “AA content”)
Sample / distilled water = 1 g / 2 cc of glass ampoule substituted with nitrogen was sealed and subjected to extraction treatment at 160 ° C for 2 hours. After cooling, acetaldehyde in the extract was measured by high-sensitivity gas chromatography. The concentration was expressed in ppm. In the case of the chip, the sample is used as it is, and the preform is a sample collected to a size of about 2 mm from the plug portion. The AA content of the polyester composition was obtained by calculating a weighted average value of the AA content of the polyester constituting the polyester composition.
Further, the variation value (ΔAA) of the acetaldehyde content of the molded body was measured for 10 pieces, and the difference between the maximum value and the minimum value was obtained.

(6) Antimony content, germanium content, aluminum content, titanium content of polyester About 1 to 10 g of sample was put into a platinum crucible and ashed at about 550 ° C., then dissolved in 6N hydrochloric acid and evaporated to dryness. Dissolve the difference in 1N hydrochloric acid. This solution was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation.

(7) Sodium content and calcium content of polyester About 5 to 10 g of a sample is put into a platinum crucible and incinerated at about 550 ° C., then dissolved in 6N hydrochloric acid and evaporated to dryness, and the residue is dissolved in 1N hydrochloric acid. This solution was measured by atomic absorption spectrometry.

(8) Silicon content of polyester About 5 to 10 g of a sample is put in a platinum crucible and incinerated at about 550 ° C., then sodium carbonate is added and dissolved by heating, and dissolved in 1N hydrochloric acid. This solution was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation.

(9) Sodium content, magnesium content, calcium content and silicon content of chip cooling water or treated water Chip cooling water is collected and filtered through a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., and the filtrate is supplied to Shimadzu Corporation. Measurement was performed with an inductively coupled plasma emission spectrometer.

(10) Polyester terminal carboxyl group concentration (AV)
200 mg of a frozen and pulverized and dried sample was dissolved by heating in 10 ml of benzyl alcohol, diluted with 10 ml of chloroform, and titrated with 0.01N potassium hydroxide / benzyl alcohol solution with phenol red as an indicator, and quantified.
The total end group concentration (TEnV) (eq / ton) was determined from the following equation.
TEnV = {2 × 10 ⁶ / (1359 × IV)} ^1.460
The ratio of terminal carboxyl groups to the total number of terminal groups (AV / TEnV) (equivalent%) was determined from the following formula.
100 x terminal carboxyl group concentration (AV) / total terminal group concentration (TEnV)

(11) Fine content measurement About 0.1 kg of resin is placed on a sieve (diameter 20 cm) with an open wire mesh that does not allow a regular-sized chip to pass through, and fines are separated while flowing ion-exchanged water. And collected. This operation was repeated for a total of 20 kg. However, when the fine content is small, the amount of the sample is appropriately changed.

The separated fines were collected by filtration with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd. using a vacuum filtration device. 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.
In the case of the following examples, a sieve (A) with a wire mesh having a nominal size of 1.7 mm according to JIS-Z8801 was used.

(12) Melting point of fine Measured using a differential scanning calorimeter (DSC) manufactured by Seiko Denshi Kogyo Co., Ltd., RDC-220. In the above (11), fines collected from 20 kg of polyester were freeze-ground and dried under reduced pressure at 25 ° C. for 3 days. From then on, 4 mg of sample was used for one measurement, and DSC was performed at a heating rate of 20 ° C./min. Measure and obtain the melting peak temperature on the highest temperature side of the melting peak temperature. The measurement is performed on a maximum of 10 samples, and the average value of the melting peak temperatures on the highest temperature side is obtained. If there is a single melting peak, the temperature is determined.

(13) Ratio of average weight (W) of polyester chip to average weight (W _A / W _B )
After removing fines with ion-exchanged water, the weight of 100 dried polyester chips was measured, and the average value was defined as the average weight (W). When the polyester composition is a mixture of two kinds of polyesters, the ratio of the average weight of the polyester chips between the two kinds (W _A / W _B ) is the average weight of the polyester chips having a larger average weight among the two kinds. and W _a, the average weight of the average weight of small polyester chips as _{W B,} was calculated _W a / W _B. When the two types of polyester chips have the same average weight, W _A / W _B is 1.00. Moreover, when it consists of 2 or more types of polyester, it calculates as mentioned above for 2 types of polyester with many mixing ratios.
In this case, the selection of 100 chips was performed by excluding abnormally sized chips. The specific chip exclusion method is as follows.
In calculating the average weight (W) of the chips, 100 chips were randomly selected, and after calculating the average weight (W), the chips having a weight of less than 0.5 W and the chips having a weight of more than 2 W were excluded and excluded. A number of chips were picked again at random, replenished and 100 averages recalculated. This was done until all 100 chips were within 0.5W-2W.

(14) Crystallization temperature (Tc1) during temperature increase and crystallization temperature (Tc2) during temperature decrease of the molded body
Measured with a differential thermal analyzer (DSC), RDC-220, manufactured by Seiko Electronics Industry Co., Ltd. A 10 mg sample from the center of a 2 mm thick plate of the molded plate described later (18) is used. In the case of a preform, a sample was taken from the trunk. The temperature was raised at a rate of 20 ° C./minute and held at 290 ° C. for 3 minutes, then the temperature was lowered from 290 ° C. to 240 ° C. at 10 ° C./minute, and further from 240 ° C. to 130 ° C. at 7 ° C./minute. The temperature dropped. The peak temperature of the crystallization peak observed at the time of temperature rise is defined as the crystallization temperature (Tc1) at the time of temperature increase, and the peak temperature of the crystallization peak observed at the time of temperature decrease is defined as the crystallization temperature (Tc2).

(15) Haze (degree of haze) and haze spots (%)
A sample was cut from the preformed body (thickness 3.7 mm) of (17) below, and measured with a Nippon Denshoku haze meter, model NDH2000. However, the measurement was performed by filling the cell with liquid paraffin.
Moreover, the haze of the preformed body molded 10 times continuously was measured, and the haze spots were determined as follows.
Haze spots (%) = maximum value of haze (%) − minimum value of haze (%)

(16) Molding of stepped molded plate
As shown in FIG. 1 and FIG. 2, the polyester dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours using a vacuum drier is injection-molded by an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho. 2 mm to 11 mm having part (G) (A part thickness = 2 mm, B part thickness = 3 mm, C part thickness = 4 mm, D part thickness = 5 mm, E part thickness = 10 mm, F part thickness) = 11 mm) thick stepped molding plate was injection molded.

Polyester previously dried under reduced pressure using a vacuum dryer DP61 manufactured by Yamato Scientific Co., Ltd. was used, and a dry inert gas (nitrogen gas) purge was performed in the molding material hopper to prevent moisture absorption during molding. The plasticizing conditions of the M-150C-DM injection molding machine are as follows: feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, cylinder temperature 45 ° C., 250 ° C. from the bottom of the hopper in order, nozzle The temperature was set at 290 ° C. The injection conditions are 20% for injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2 g. In this case, the holding pressure is 0.5 MPa relative to the injection pressure. Adjusted low.
The upper limit of the injection time and pressure holding time is set to 10 seconds and 7 seconds, respectively, and the cooling time is set to 50 seconds. The total cycle time including the time for taking out the molded product is about 75 seconds.
Although the temperature of the mold is always controlled by introducing cooling water having a water temperature of 10 ° C., the mold surface temperature at the time of stable molding is around 22 ° C.

The test plate for evaluating the molded product characteristics was arbitrarily selected from the 11th to 18th shots of the stable molded product after the molding material was introduced and the resin was replaced.
The molding temperature refers to the set temperature of the barrel including the nozzle.
A 2 mm-thick plate (part A in FIG. 1) is used to measure the crystallization temperature (Tc1) during temperature rise and the crystallization temperature (Tc2) during temperature fall.

(17) Molding of preform and hollow molded body In the same manner as in the above (16), in order to prevent moisture absorption during molding, using polyester dried in advance using a vacuum dryer DP61 type manufactured by Yamato Scientific Co., Ltd. The molding material hopper was purged with a dry inert gas (nitrogen gas). With each machine manufacturer M-150C-DM injection molding machine, the cylinder temperature is set to 50 ° C, 250 ° C in order from right under the hopper, 280 ° C including the nozzle, and the hot runner temperature is also set to 280 ° C. 50 seconds, injection pressure 1.8-2.3 kg / cm ² , back pressure 0.5Mp, screw rotation speed 120rpm, feed screw rotation speed 84rpm 29.4 mm, length 145.5 mm, wall thickness approximately 3.7 mm, weight 60 g). The surface temperature of the mold when molding is stable is around 22 ° C.

The plug parts of these preforms were heat-treated for 180 seconds with a homemade infrared heater, and then a mold pin was inserted to heat-crystallize the plug part. Next, this preform was biaxially stretched and blown with a LB-01E molding machine manufactured by CORPOPLAST, and then heat-set in a mold set at about 150 ° C. for about 5 seconds to form a container having a capacity of 1500 cc. The stretching temperature was controlled at 100 ° C.
The molten resin temperature was measured by bringing a thermocouple thermometer into contact with the molten resin injected from the nozzle tip of the injection molding machine.

(18) Appearance of Hollow Molded Body Twenty hollow molded bodies from the tenth molding start of (17) were visually observed and evaluated as follows.
◎: Transparent and no appearance problems △: There is a little whitened flow pattern or whitened product in the hollow molded body ×: White flowed pattern or whitened product in the hollow molded body

(19) Shape and size of the plug portion of the preform for the hollow molded body The shape and size of the preform plug portion crystallized in (17) above was visually observed and evaluated as follows.
A: Extremely stable dimensional accuracy was obtained.
○: Stable dimensional accuracy was obtained.
X: Insufficient crystallization, poor shape, or excessive crystallization, poor dimensionality.

(Polyester 1 (Pes1))
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. Moreover, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were continuously supplied separately to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The obtained PET resin had an intrinsic viscosity (IV) of 0.53 deciliter / gram and a DEG content of 2.6 mol%.
The cooling water at the time of chip formation is ion exchange water having a sodium content of 0.1 ppm, a calcium content of about 0.1 ppm, a magnesium content of about 0.05 ppm, and a silicon content of about 0.7 ppm. Using.

  After fine removal of this resin, it was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 208 ° C. under a nitrogen atmosphere. . After the solid phase polymerization, fines were removed by continuous treatment in a sieving step and a fine removal step.

The intrinsic viscosity of the obtained PET is 0.70 deciliter / gram, AV / TEnV is 14%, acetaldehyde (AA) content is 3.4 ppm, cyclic trimer content is 0.35% by weight, and the chip shape is elliptical. It is columnar, the average chip weight (W) is 24.1 mg, the chip density is 1.400 g / cm ³ (the density of the polyester chip is measured at 30 ° C. with a density gradient tube of calcium nitrate / water solution), and the sodium content is 0.05 ppm, calcium content was 0.07 ppm, silicon content was 0.6 ppm, and fine content was about 50 ppm. The properties of the obtained PET are shown in Table-1.

(Polyester 2 (Pes2), 3 (Pes3))
Polyesters 2 and 3 were obtained by reacting in the same manner as polyester 1 except that the polycondensation catalyst addition amount, phosphoric acid addition amount, and solid phase polymerization time were changed. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 4 (Pes4))
Polyester 4 was obtained by reacting in the same manner as for polyester 1 except that the polycondensation catalyst addition amount, phosphoric acid addition amount, solid phase polymerization time, and average chip weight were changed. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 5 (Pes5))
The reaction is carried out in the same manner as for polyester 1 except that the esterification conditions, polycondensation catalyst addition amount, phosphoric acid addition amount, IV of the melt polycondensation polymer, the quality of the cooling water during chip formation and the solid phase polymerization time are changed. A phase polymer was obtained. The properties of the obtained PET are shown in Table-1. As the cooling water during chip formation, water having a sodium content of about 10.5 ppm, a calcium content of about 12.5 ppm, a magnesium content of about 5.9 ppm, and a silicon content of 12.2 ppm was used. The sodium content of Pes5 was 6.3 ppm, the calcium content was 5.8 ppm, and the silicon content was 6.6 ppm.

(Polyester 6 (Pes6))
A solid phase polymerization polymer was obtained by reacting in the same manner as for polyester 1 except that the esterification conditions, polycondensation catalyst addition amount, phosphoric acid addition amount, IV of the melt polycondensation polymer and the solid phase polymerization time were changed. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 7 (Pes7))
The solid phase polymerized polymer was reacted in the same manner as polyester 1 except that the polycondensation catalyst addition amount, phosphoric acid addition amount, IV of the melt polycondensation polymer, the quality of the cooling water during chip formation and the solid phase polymerization time were changed. Obtained. The properties of the obtained PET are shown in Table-1. As the cooling water at the time of chip formation, water of the same quality as at the time of production of polyester 5 was used. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 8 (Pes8), 9 (Pes9))
As the polycondensation catalyst, the same procedure as for polyester 1 or polyester 2 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution in which ethylene glycol is preheated is used. By reacting, polyesters 8 and 9 were obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 10 (Pes10))
As polycondensation catalyst, ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and ethylene glycol solution heat-treated in advance with ethylene glycol, IV of melt polycondensation polymer and solid phase polymerization A polyester 10 was obtained by reacting in the same manner as the polyester 7 except that the time was changed. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 11 (Pes11))
As polycondensation catalyst, ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and ethylene glycol solution heat-treated in advance with ethylene glycol, IV of melt polycondensation polymer and solid phase polymerization A polyester 11 was obtained by reacting in the same manner as the polyester 1 except that the time was changed. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 12 (Pes12), 13 (Pes13))
As a polycondensation catalyst, polyester 12 is prepared by reacting in the same manner as polyester 1 or polyester 2, except that an ethylene glycol solution of titanium tetrabutoxide, an ethylene glycol solution of magnesium acetate tetrahydrate, and an ethylene glycol solution of ethyl acid phosphate are used. 13 was obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 14 (Pes14))
As the polycondensation catalyst, an ethylene glycol solution of titanium tetrabutoxide, an ethylene glycol solution of magnesium acetate tetrahydrate, an ethylene glycol solution of ethyl acid phosphate, except for changing the IV of the melt polycondensation polymer and the solid phase polymerization time. Reaction was carried out in the same manner as for polyester 7 to obtain polyester 14. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 15 (Pes15))
Except for changing the IV and solid phase polymerization time of the melt polycondensation polymer using an ethylene glycol solution of titanium tetrabutoxide, an ethylene glycol solution of magnesium acetate tetrahydrate, an ethylene glycol solution of ethyl acid phosphate as the polycondensation catalyst In the same manner as in Example 1, polyester 15 was obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 16 (Pes16), 17 (Pes17))
As a polycondensation catalyst, polyesters 16 and 17 were reacted by reacting in the same manner as polyester 1 or polyester 2 except that antimony trioxide ethylene glycol solution, magnesium acetate tetrahydrate ethylene glycol solution, and phosphoric acid ethylene glycol solution were used. Obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 18 (Pes18))
Polyester 7 except that the polycondensation catalyst was an antimony trioxide ethylene glycol solution, magnesium acetate tetrahydrate ethylene glycol solution, phosphoric acid ethylene glycol solution, and the melt polycondensation polymer IV and solid phase polymerization time were changed. In the same manner as above, polyester 10 was obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 19 (Pes19))
Polyester 1 is used except that an antimony trioxide ethylene glycol solution, magnesium acetate tetrahydrate ethylene glycol solution, phosphoric acid ethylene glycol solution is used as the polycondensation catalyst, and the melt polycondensation polymer IV and solid phase polymerization time are changed. In the same manner as above, polyester 15 was obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 20 (Pes20))
The polyester 1 is water-treated by continuously feeding it from the supply port (1) at the upper part of the treatment tank to the following water treatment tank controlled at a treatment water temperature of 95 ° C. at a rate of 50 kg / hour. A PET chip was continuously extracted from the discharge port (3) with treated water at a rate of 50 kg / hour. The introduced water collected before the ion exchange water inlet (9) of the water treatment apparatus has a particle content of about 1000 particles / 10 ml, a sodium content of 0.03 ppm, and a magnesium content of 0.1. 06 ppm, calcium content 0.05 ppm, silicon content 0.10 ppm, and the number of particles having a particle size of 1 to 40 μm of recycled water after treatment in the filtration device (5) and the adsorption tower (8) is about 10,000. Pieces / 10 ml. After the water treatment, fines and the like were removed in the same manner as in Example 1.

For water treatment of polyester chips, the apparatus shown in FIG. 3 is used. The raw material chip supply port (1) at the upper part of the treatment tank, the overflow discharge port (2) located at the upper limit level of the treatment water in the treatment tank, and the lower part of the treatment tank A discharge port (3) for the mixture of polyester chip and treated water, treated water discharged from the overflow discharge port, treated water discharged from the treatment tank, and draining device discharged from the discharge port at the bottom of the treatment tank ( 4) The treated water passed through 4) is again sent to the water treatment tank via the fine powder removing device (5) whose filter medium is a paper-made continuous filter, and these fine powder removed treated water. Uses an inlet (7), an adsorption tower (8) for adsorbing acetaldehyde in treated water from which fine particles have been removed, and a tower-type treatment tank with an internal capacity of about 50 m ³ equipped with a new ion-exchange water inlet (9) did. The properties of the obtained PET are the same as the properties of polyester 1 described in Table 1, except that the cyclic trimer increase amount (ΔCT amount) upon melting is 0.14% by weight. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 21 (Pes21))
Polyester 2 was treated with water in the same manner as described above to obtain polyester 21.
The properties of the obtained PET are the same as the properties of the polyester 2 described in Table 1, except that the cyclic trimer increase amount (ΔCT amount) upon melting is 0.14% by weight. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyamide 1 (Pam1))
Toyobo nylon MXD6 resin T640 manufactured by Toyobo Co., Ltd. was used.

(Example 1)
A polyester composition obtained by blending the above-mentioned polyester 1 and polyester 2 pellets in a ratio of 7: 3 is obtained by molding at 290 ° C. by the method (16) and by injection molding by the method (17). Evaluations were also made on preforms and hollow molded containers. The results are shown in Table 2. The AA content of the preform is 8.2 ppm, the fluctuation value is 0.3 ppm, and the haze and haze spots are 1.5% and 0.5%, respectively, which is not a problem value. There was no problem in the shape and size after crystallization, and the appearance of the stretched hollow molded article was also satisfactory.

(Example 2)
The polyester composition of Example 2 was evaluated in the same manner as in Example 1 with the composition shown in Table 2 using a mixture of water-treated PET. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1. Further, the amount of increase in cyclic trimer (ΔCT amount) at the time of melting was as small as 0.13% by weight.

(Comparative Example 1)
As shown in Table 2, the polyester 3 of Comparative Example 1 was evaluated in the same manner as in Example 1. Obviously, the AA content of the preform and its fluctuation value, haze value and haze spots are large compared to the examples, and the shape and dimensions of the preformed body plug after crystallization are insufficiently crystallized. The appearance of the stretched hollow molded article was poor. The results are shown in Table 2.

(Comparative Example 2)
As shown in Table 2, the polyester composition of Comparative Example 2 was evaluated. Obviously, the haze value and haze spots of the preform were high, the shape and size after crystallization of the preform plug portion were poor, and the appearance of the stretched hollow mold was poor as compared with the examples. The results are shown in Table 2.

(Comparative Example 3)
As shown in Table 2, the polyester composition of Comparative Example 3 was evaluated. Obviously, the AA content of the preform and its fluctuation value, haze value and haze spots are high, and the shape and dimensions of the preformed body plug after crystallization are poor, compared with the examples, and stretched hollow The appearance of the molded body was also bad. The results are shown in Table 2.

(Comparative Example 4)
As shown in Table 2, the polyester composition of Comparative Example 4 was evaluated. Obviously, the AA content of the preform and its fluctuation value, haze value and haze spots are high, and the shape and dimensions of the preformed body plug after crystallization are poor, compared with the examples, and stretched hollow The appearance of the molded body was also bad. The results are shown in Table 2.

(Comparative Example 5)
As shown in Table 2, the polyester composition of Comparative Example 5 was evaluated. Obviously, the AA content of the preform and its fluctuation value, haze value and haze spots are high, and the shape and dimensions of the preformed body plug after crystallization are poor, compared with the examples, and stretched hollow The appearance of the molded body was also bad. The results are shown in Table 2.

(Example 3)
According to the composition shown in Table 3, the polyester composition of Example 3 was evaluated in the same manner as in Example 1. The results are shown in Table 3. All the evaluated characteristics were as good as in Example 1.

Example 4
According to the composition shown in Table 3, the polyester composition of Example 4 was evaluated in the same manner as in Example 1. The results are shown in Table 3. All the evaluated characteristics were as good as in Example 1.

(Example 5)
According to the composition shown in Table 3, the polyester composition of Example 5 was evaluated in the same manner as in Example 1. The results are shown in Table 3. All the evaluated characteristics were as good as in Example 1.

(Example 6)
According to the composition shown in Table 3, the polyester composition of Example 6 was evaluated in the same manner as in Example 1. The results are shown in Table 3. All the properties evaluated were further improved in AA content than in Example 1, and the other properties were as good as in Example 1.

(Comparative Examples 6-8)
As shown in Table 3, the polyester compositions of Comparative Examples 6, 7, and 8 were evaluated. Obviously, the AA content of the preform and its fluctuation value, haze value and haze spots are high, and the shape and dimensions of the preformed body plug after crystallization are poor, compared with the examples, and stretched hollow The appearance of the molded body was not good. The results are shown in Table 3.

  As mentioned above, although the polyester composition of this invention and the polyester molded object which consists of it were demonstrated based on several Example, this invention is not limited to the structure described in the said Example, It describes in each Example. The configurations can be appropriately changed without departing from the gist of the configurations, for example, by appropriately combining the configurations.

  In the present invention, transparency is maintained even by molding at a lower temperature, the amount of acetaldehyde generated and the amount of cyclic trimer generated is suppressed, and when formed into a molded body, a molded body excellent in mechanical properties is obtained. A polyester composition is provided. In addition, the polyester composition of the present invention has improved moldability at a lower temperature, so there is less distortion during molding, and a molded body excellent in heat-resistant dimensional stability, particularly a hollow molded product, can be produced efficiently by high-speed molding. In addition, a molded body having good pressure resistance and heat-resistant dimensional stability can be obtained. Moreover, the polyester composition excellent in the long-time continuous moldability which does not stain a metal mold | die, and a molded object consisting of them are provided. The polyester composition of the present invention can meet high required quality in the field of containers, sheets and the like.

Plan view of stepped plate Side view of stepped plate It is the schematic of the water treatment apparatus used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material chip supply port 2 Overflow discharge port 3 Discharge port of polyester chip and treated water 4 Drainage device 5 Fine removal device 6 Pipe 7 Recycled water and / or ion exchange water introduction port 8 Adsorption tower 9 Ion exchange water introduction port

Claims (8)

A polyester composition comprising, as a main component, at least two polyesters mainly composed of ethylene arylate, wherein the polyester has a difference in intrinsic viscosity of 0.05 to 0.25 deciliter / gram, The polyester composition is characterized in that the difference in the crystallization temperature during temperature drop is within 20 ° C., and the content of atoms used as a polycondensation catalyst in the polyester composition satisfies the following formula (1).
1 ≦ (A / 25) + (B / 5) + (C / 3) + D ≦ 15 (1)
(In the formula, A, B, C, and D represent the antimony atom content, germanium atom content, aluminum atom content, and titanium atom content, respectively, in the polyester composition. The unit is ppm) 2. The polyester composition according to claim 1, wherein the relationship between the content E of phosphorus atoms in the polyester composition and A, B, C, and D satisfies the following formula (2).
0.1 ≦ {(A / 25) + (B / 5) + (C / 3) + D} / E ≦ 5 (2)
(In the formula, E represents the phosphorus atom content in the polyester composition. The unit is ppm)   3. The polyester composition according to claim 1, wherein the terminal carboxyl group concentration with respect to the total number of terminal groups of each polyester is 5 to 40 equivalent%.   The polyester composition according to claim 1, 2 or 3, wherein the content of the cyclic ester oligomer in the polyester composition is 70% or less of the content of the cyclic ester oligomer in the melt polycondensation polyester prepolymer.   The ratio of the average weight (W) and average weight (W) of each polyester chip is 5 to 50 mg and 1.00 to 1.30, respectively. Polyester composition. The polyester composition is a polyester composition having ethylene terephthalate as a main repeating unit, comprising the following polyester A and polyester B as main components, the crystallization temperature of polyester A at elevated temperature and the rise of polyester B: The polyester composition according to claim 1, 2, 3, 4, or 5, wherein the difference from the warm crystallization temperature is within 10 ° C.
Polyester A: Intrinsic Viscosity IV _A is 0.60 to 0.80 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at temperature increase measured by DSC is 140 to 180 ° C., and crystallization temperature at temperature decrease is 160 to 160 ° C. Polyester at 200 ° C.
Polyester B: Intrinsic viscosity IV _B is 0.73 to 0.95 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at the time of temperature increase measured by DSC is 140 to 180 ° C., and crystallization temperature at the time of temperature decrease is 160 to Polyester at 200 ° C.   A polyester molded article obtained by molding the polyester composition according to claim 1, 2, 3, 4, 5 or 6.   The polyester molded body is any one selected from a preform for a hollow molded body, a sheet-shaped preform, or a stretched film formed by stretching these preforms in at least one direction or a stretch blow hollow molded body. A polyester molded article characterized by

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