JP2003105075A - Production method for polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester which gives a transparent molded article exhibiting good crystallization at a plug part and hardly causing the variation in crystallization rate. SOLUTION: This polyester is produced by reacting a dicarboxylic acid mainly comprising an aromatic dicarboxylic acid or an ester-forming derivative thereof with a glycol or an ester-forming derivative thereof in the presence of crystalline germanium dioxide containing not more than 100 ppm alkali metal as a polycondensation catalyst to give a low polycondensate and then polycondensing the low polycondensate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyesters used for forming films, sheets, etc., including bottles, and more specifically, a molded product excellent in color tone and transparency and having little fluctuation in crystallization rate. To a method for producing a polyester.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter simply referred to as "PET"), polybutylene terephthalate (hereinafter simply referred to as "PBT"), polyethylene naphthalate (hereinafter simply referred to as "PEN"), and the like. Polyester has excellent mechanical properties and chemical properties. Depending on the properties of each polyester, hollow molded articles such as bottles, films for packaging and magnetic tapes, sheets for packaging, electrical, etc. It is used in a wide range of fields such as molding materials for electronic parts.

Among these polyesters, especially polyethylene terephthalate is a carbonated beverage due to its excellent transparency, mechanical strength, heat resistance and gas barrier property.
It has been adopted as a material for sheets for beverages such as juice and mineral water, and containers for semi-prepared frozen foods such as gratin, and its spread is remarkable. Generally, PET used for such applications is mainly produced from terephthalic acid and ethylene glycol as raw materials, and using polycondensation catalysts such as antimony compounds, titanium compounds, germanium compounds and mixtures thereof.

In these applications, a polyester bottle is hot-filled with a beverage sterilized at a high temperature, or is sterilized at a high temperature after being filled with a beverage. There is a problem that shrinkage and deformation occur in etc. As a method for improving the heat resistance of a polyester bottle, a method has been proposed in which the bottle mouth plug is heat-treated to increase the crystallinity, or the stretched bottle is heat-fixed. In particular, when the crystallization of the spout is insufficient or the crystallization degree varies greatly, the sealing property with the cap may be deteriorated and the contents may leak.

Further, in the case of beverages such as fruit juice drinks, oolong tea and mineral water which require hot filling, a method of heat-treating the preform or the mouth part of a molded bottle to crystallize it (JP The methods described in JP-A-55-79237 and JP-A-58-110221 are generally used. In such a method, that is, a method of heat-treating the plug portion and the shoulder portion to improve heat resistance, the time and temperature of the crystallization treatment greatly affect the productivity, and the treatment can be performed at a low temperature in a short time. It is preferable that PET has a high rate of conversion. On the other hand, the body portion is required to be transparent even when subjected to heat treatment at the time of molding so as not to deteriorate the color tone of the bottle content, and the spout portion and the body portion need to have contradictory properties.

Among the above-mentioned catalysts, the antimony catalyst is a catalyst which is inexpensive and has excellent catalytic activity, but the main component, that is, the amount added so that a practical polycondensation rate is exhibited. However, since the metal antimony is precipitated during the polycondensation, there is a problem that darkening and foreign matter are generated in the polyester.

The crystallization rate of PET using an antimony catalyst as a polycondensation catalyst may be due to the above-mentioned foreign substances.
It is very difficult to obtain a heat-resistant hollow molded article that is faster and has excellent transparency, especially a large heat-resistant hollow molded article, as compared with the case where a germanium compound or a titanium compound is used as a catalyst. Further, the above-mentioned foreign matter may be present in the hollow molded article, which lowers the commercial value. Under such circumstances, polyesters containing no antimony or no antimony as a catalyst main component are desired. When PET obtained by using an antimony catalyst as a polycondensation catalyst is used as a sheet material, the following problems occur during sheet molding. Precipitation of metal antimony causes pressure increase in the extruder due to filter clogging during sheet forming, which shortens the filter replacement cycle and causes a cost increase. In addition, it causes lip stains on the sheet forming die, which increases the frequency of adhesion of lip stains to the sheet surface, resulting in poor product yield. Therefore,
Also in the production of polyester sheets, a polyester polycondensation catalyst that does not generate foreign matter is required.

[0008] Polycondensation catalysts replacing antimony-based catalysts such as antimony trioxide have also been studied, and titanium compounds and tin compounds represented by tetraalkoxy titanates have already been proposed. Further, polyester has a problem that it is susceptible to thermal deterioration during melt molding and that the polyester is markedly colored.
Further, there is also a problem that the crystallization speed is very slow, it takes a long time to crystallize the spout when producing the heat-resistant hollow molded article, and the productivity is lowered.

As an attempt to overcome the above problems when a titanium compound is used as a polycondensation catalyst, for example, in JP-A-55-116722, a method in which a tetraalkoxy titanate is used at the same time as a cobalt salt and a calcium salt is used. Is proposed. Also, Japanese Patent Laid-Open No. 8-735
No. 81 proposes a method in which a tetraalkoxy titanate is used as a polycondensation catalyst at the same time as a cobalt compound and an optical brightener is used. However, although these techniques reduce the coloring of PET when tetraalkoxy titanate is used as a polycondensation catalyst, P
Effective suppression of thermal decomposition of ET has not been achieved.

As another attempt to suppress thermal deterioration during melt molding of polyester polycondensed using a titanium compound as a catalyst, for example, in Japanese Patent Laid-Open No. 10-259296,
A method is disclosed in which a phosphorus compound is added after polycondensation of polyester using a titanium compound as a catalyst. However, it is not technically difficult to effectively mix the additive into the polymer after polycondensation, and it is not practically used because of cost increase.

Germanium compounds have already been put to practical use as catalysts which give polyesters having excellent catalytic activity other than antimony compounds and excellent thermal stability and thermal oxidation stability. Although this catalyst has a problem that it is very expensive, it has a relatively good solubility in a polymer and a polymer having a considerably high transparency can be obtained. It is mainly used as a condensation catalyst. However, the transparency and crystallization rate of the bottle may not be stable, which is not satisfactory.

[0012]

DISCLOSURE OF THE INVENTION The present invention is to solve the problems of the prior art and provides a molded product having excellent transparency and little fluctuation in crystallization rate, and the molded product contains almost no foreign matter. And polyester-filter-a method for producing polyester with low rise in filtration pressure.

[0013]

In order to achieve the above object, a crystalline dicarboxylic acid having an alkali metal content of 100 ppm or less as a polycondensation catalyst is used as a polycondensation catalyst, or a dicarboxylic acid containing an aromatic dicarboxylic acid as a main component or an ester thereof. A method for producing a polyester, which comprises obtaining a low polycondensate from a forming derivative and glycol or an ester forming derivative thereof, and then polycondensing the low polycondensate.

In this case, Mg, Al, Si, T
i, Mn, Fe, Co, Zn, Ga, Sr, Zr, S
A compound containing at least one element selected from the group consisting of n, Sb, W and Pb can coexist. In this case, the residual amount of the compound containing at least one element according to claim 2 is 0.0001 to 0.3 as an element with respect to the acid component of the polyester.
It can be mol%. In this case, the polyester has a sodium content (N), a magnesium content (M), a silicon content (S), and a calcium content (C) as shown in the following (1) to (4). The polyester may be formed into chips while cooling with cooling water satisfying at least one of them. N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4) In this case, The content of either the fine content, the film-like material content, or the total content of the fine content and the film-like material content is 500.
It can be 0 ppm or less.

Here, fine means JIS-Z8801.
According to JIS means fine powder of polyester that has passed through a sieve having a mesh size of 1.7 mm, and a film-like material remains on a sieve having a mesh size of 5.6 mm according to JIS-Z8801. Of polyester, it means a film-like material after two or more chips are fused or the chip-like material cut into pieces larger than the normal shape is removed, and the content thereof is measured by the following measuring method. .

In this case, the polyester obtained by injection molding has an intrinsic viscosity of 0.55 to 1.5 deciliter / gram, an acetaldehyde content of 10 ppm or less, and a cyclic trimer content of 0.5% by weight or less. The formed plate has a haze of 15% or less, a crystallization temperature (Tc1) measured by DSC when the formed plate is heated is 150 to 175 ° C., and spherulites formed when the formed plate is heated and crystallized. Number is 2 × 10 ⁹
The polyester having ethylene terephthalate as a main repeating unit in the range of up to 15 × 10 ⁹ units / m ² can be used.

Here, the number of spherulites formed in the case of crystallization at elevated temperature means the number of spherulites measured by the method described later. In this case, the polyester can be treated by contact with water. In this case, the polyester may be blended with at least one resin selected from the group consisting of polyolefin resin, polyamide resin, and polyacetal resin.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method for producing a polyester of the present invention will be specifically described below. The polyester according to the present invention is a thermoplastic polyester comprising a dicarboxylic acid containing an aromatic dicarboxylic acid as a main component or an ester-forming derivative thereof and a glycol or an ester-forming derivative thereof, and preferably an aromatic dicarboxylic acid. A thermoplastic polyester in which the acid unit contains 85 mol% or more of the acid component, more preferably a thermoplastic polyester in which the aromatic dicarboxylic acid unit contains 90 mol% or more of the acid component, and particularly preferably the aromatic dicarboxylic acid unit is the acid component. Is 95% by mole or more of the thermoplastic polyester.

The aromatic dicarboxylic acid component constituting the polyester according to the present invention includes terephthalic acid, 2,6-
Examples thereof include aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid and diphenoxyethanedicarboxylic acid, and functional derivatives thereof.

As the glycol component constituting the polyester according to the present invention, ethylene glycol, 1,3
Examples include alicyclic glycols such as trimethylene glycol, tetramethylene glycol, cyclohexanedimethanol, and the like.

The acid component used by copolymerization in the polyester is terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyl-4,4 '.
-Aromatic dicarboxylic acids such as dicarboxylic acid and diphenoxyethanedicarboxylic acid, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, glutaric acid, dimer acid And aliphatic dicarboxylic acids and functional derivatives thereof, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid, and functional derivatives thereof.

The glycol component used by copolymerization in the polyester is ethylene glycol, 1,
Aliphatic glycols such as 3-trimethylene glycol, tetramethylene glycol, diethylene glycol and neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, aromatic glycols such as bisphenol A and alkylene oxide adducts of bisphenol A, polyethylene glycol- And polyalkylene glycol such as polybutylene glycol.

Further, as the polyfunctional compound as a copolymerization component used when the polyester is a copolymer, examples of the acid component include trimellitic acid and pyromellitic acid. Examples of the component include glycerin and pentaerythritol. The amount of the above copolymerization component used should be such that the polyester maintains a substantially linear shape. Further, a monofunctional compound such as benzoic acid or naphthoic acid may be copolymerized.

A preferred example of the thermoplastic polyester according to the present invention is a thermoplastic polyester whose main repeating unit is ethylene terephthalate, more preferably 85 mol% of ethylene terephthalate unit.
A linear copolymerized thermoplastic polyester containing the above and including isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedimethanol as a copolymerization component, and particularly preferably 9 ethylene terephthalate units.
It is a linear thermoplastic polyester containing 5 mol% or more. Examples of these linear thermoplastic polyesters include polyethylene terephthalate (hereinafter abbreviated as PET), poly (ethylene terephthalate-ethylene isophthalate) copolymer, poly (ethylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer Examples thereof include a polymer, a poly (ethylene terephthalate-ethylene-2,6-naphthalate) copolymer, and a poly (ethylene terephthalate-dioxyethylene terephthalate) copolymer.

In another preferred example of the thermoplastic polyester according to the present invention, the main repeating unit is ethylene-
A thermoplastic polyester composed of 2,6-naphthalate, more preferably a linear thermoplastic polyester containing 85 mol% or more of ethylene-2,6-naphthalate units, particularly preferably ethylene. -2, 6-
It is a linear thermoplastic polyester containing 95 mol% or more of naphthalate units. Examples of these linear thermoplastic polyesters include polyethylene-2,6-naphthalate, poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, poly (ethylene-2,6-naphthalate-ethylene isophthalate). Copolymer, poly (ethylene-2,6-naphthalate-dioxyethylene-
2,6-naphthalate) copolymer and the like.

Other preferred examples of the polyester according to the present invention include linear polyesters containing 1,3-propylene terephthalate units in an amount of 85 mol% or more, 1,4.
-Cyclohexane dimethylene terephthalate unit 85
It is a linear polyester containing not less than mol% or a linear polyester containing not less than 85 mol% of butylene terephthalate units.

The method for producing the polyester of the present invention will be explained by taking polyethylene terephthalate as an example. This is because terephthalic acid, ethylene glycol and, if necessary, other copolymerization components are directly reacted to distill off water and esterify the product. A direct esterification method in which polycondensation is carried out under reduced pressure using a polycondensation catalyst, or dimethyl terephthalate and ethylene glycol and optionally other copolymerization components are reacted in the presence of an ester exchange catalyst to distill off methyl alcohol. However, after the transesterification, a melt polycondensed polyester is produced by any of the transesterification methods in which polycondensation is carried out under reduced pressure using a polycondensation catalyst. Further, it is a method for producing a polyester in which solid phase polymerization is carried out in order to increase the intrinsic viscosity and reduce the acetaldehyde content and the like, if necessary. In order to accelerate crystallization before solid-phase polymerization, the molten polycondensed polyester may be adsorbed with moisture and then crystallized by heating, or steam may be directly blown onto the polyester chips to be crystallized by heating.

The melt polycondensation reaction may be carried out in a batch reaction apparatus or a continuous reaction apparatus.
In any of these methods, the melt polycondensation reaction may be carried out in one step or may be carried out in multiple steps. The solid phase polymerization reaction can be carried out by a batch type apparatus or a continuous type apparatus as in the melt polycondensation reaction. The melt polycondensation and solid phase polymerization may be carried out continuously or may be carried out separately.
Hereinafter, an example of a preferable continuous production method will be described by taking polyethylene terephthalate as an example.

First, the case of producing a low polymer by an esterification reaction will be described. 1.02-1.5 mol per 1 mol of terephthalic acid or its ester derivative,
Preferably, a slurry containing 1.03 to 1.4 mol of ethylene glycol is prepared and continuously supplied to the esterification reaction step.

In the esterification reaction, water or alcohol produced by the reaction is removed from the system in a rectification column under the condition that ethylene glycol is refluxed by using a multistage apparatus in which at least two esterification reactors are connected in series. While removing. The temperature of the first stage esterification reaction is 240 to
270 ° C, preferably 245-265 ° C, pressure 0.2
~ 3 kg / cm ² G, preferably 0.5-2 kg / cm ²
G. The temperature of the last stage esterification reaction is usually 25
0 to 280 ° C., preferably 255 to 275 ° C., the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.
It is 3 kg / cm ² G. When it is carried out in three or more stages, the reaction conditions for the intermediate stage esterification reaction are
It is a condition between the reaction conditions of the first stage and the reaction conditions of the final stage. The increase in the reaction rate of these esterification reactions is preferably distributed smoothly at each stage. Finally, the esterification reaction rate is 90% or more, preferably 93%
It is desirable to reach the above. A low-order condensate having a molecular weight of about 500 to 5000 is obtained by these esterification reactions. When terephthalic acid is used as a raw material, the above esterification reaction can be carried out without a catalyst by the catalytic action of terephthalic acid as an acid, but it may be carried out in the presence of a polycondensation catalyst.

Further, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, tetraethylammonium hydroxide, tetra-hydroxide.
When a small amount of a basic compound such as a quaternary ammonium hydroxide such as n-butylammonium or trimethylbenzylammonium hydroxide or a compound of an alkali metal or an alkaline earth metal is added to carry out the reaction, dioxy in the main chain of polyethylene terephthalate is obtained. It is preferable because the ratio of the ethylene terephthalate component unit can be maintained at a relatively low level (5 mol% or less based on the total diol component).

The alkali metal used in the present invention,
As alkaline earth metals, Li, Na, K, Rb, C
At least one selected from s, Be, Mg, Ca, Sr, and Ba is preferable, and Be, Mg, and C are particularly preferable.
The use of a, Sr is preferred. Examples of compounds of alkali metals and alkaline earth metals include formic acid of these metals,
Saturated aliphatic carboxylates such as acetic acid, propionic acid, butyric acid and oxalic acid, unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid, aromatic carboxylates such as benzoic acid,
Halogen-containing carboxylic acid salts such as trichloroacetic acid, lactic acid, citric acid, hydroxycarboxylic acid salts such as salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, hydrogen phosphate, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid,
Hydrobromic acid, chloric acid, inorganic acid salts such as bromic acid, 1-propanesulfonic acid, 1-pentanesulfonic acid, organic sulfonic acid salts such as naphthalenesulfonic acid, organic sulfates such as lauryl sulfuric acid, methoxy, ethoxy, n-propoxy,
Examples thereof include alkoxides such as iso-propoxy, n-butoxy and tert-butoxy, chelate compounds with acetylacetonate, hydrides, oxides and hydroxides.

The alkali metal used in the present invention,
The amount of the alkaline earth metal compound added is 0.0001 as the residual amount of the element with respect to the acid component of the polyester.
.About.0.1 mol%, preferably 0.001 to 0.05 mol%, and more preferably 0.005 to 0.03 mol%. When such a range is satisfied, the ratio of the dioxyethylene terephthalate component unit in the main chain is in a suitable range, the polyester has good transparency and color tone, and has a suitable crystallization rate range. Can be obtained. When the content of the compound containing these elements is less than 0.0001 mol%, the ratio of the above-mentioned dioxyethylene terephthalate component unit exceeds 5 mol% with respect to the total diol component, which is not preferable. On the other hand, if it exceeds 0.1 mol%, the crystallization rate will be too fast and the mouthpiece of the hollow molded article will be excessively crystallized, so that the amount of contraction and shrinkage of the mouthpiece will not fall within the specified range. Therefore, the capping becomes defective and the content leaks, and the preform for the hollow molded body is whitened, which makes normal stretching impossible.

Next, when a low polymer is produced by a transesterification reaction, 1.1 to 1.6 mol, preferably 1.2 to 1.5 mol of ethylene glycol is added to 1 mol of dimethyl terephthalate. The contained solution is prepared and continuously fed to the transesterification reaction step.

In the transesterification reaction, methanol produced by the reaction is removed to the outside of the system by a rectification column under the condition that ethylene glycol is distilled off using a device in which 1 to 2 transesterification reactors are connected in series. While doing. The temperature of the first-stage transesterification reaction is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the final stage transesterification reaction is usually 230 to 270 ° C., preferably 24.
0 to 265 ° C, and as a transesterification catalyst, Zn,
Fatty acid salts such as Cd, Mg, Mn, Co, Ca and Ba,
Carbonate, Pb, Zn, Sb, Ge oxide or the like is used. Due to these transesterification reactions, the molecular weight is about 200-500.
A low order condensate is obtained.

Next, the obtained low-order condensate is supplied to a multi-stage liquid phase condensation polymerization process. Regarding the polycondensation reaction conditions, the reaction temperature of the first stage polycondensation is 250 to 290 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 Torr.
r, preferably 200 to 30 Torr, and the temperature of the final polycondensation reaction is 265 to 300 ° C., preferably 275.
The pressure is 10 to 0.1 Torr, preferably 5 to 0.5 Torr. When it is carried out in three or more stages, the reaction conditions of the polycondensation reaction in the intermediate stage are those between the reaction conditions of the first stage and the reaction conditions of the final stage. The degree of increase in intrinsic viscosity reached in each of these polycondensation reaction steps is preferably distributed smoothly.

The melt polycondensed polyester thus obtained is extruded from the pores after completion of the melt polycondensation, is made into chips while being cooled with cooling water, and is then solid-phase polymerized if necessary. The above polyester is solid-phase polymerized by a conventionally known method. First, the above-mentioned polyester to be subjected to solid-phase polymerization is treated under an inert gas or under reduced pressure, or in a steam or a steam-containing inert gas atmosphere at 10
Pre-crystallization is performed by heating at a temperature of 0 to 210 ° C. for 1 to 5 hours. Then, under an inert gas atmosphere or under reduced pressure, 190
Solid phase polymerization is performed at a temperature of ~ 230 ° C for 1 to 30 hours.

In the method for producing a polyester of the present invention, crystalline germanium dioxide having an alkali metal content of 100 ppm or less is used as a polycondensation catalyst to obtain a dicarboxylic acid containing an aromatic dicarboxylic acid as a main component or an ester-forming derivative thereof. , A low polycondensate is obtained from glycol or an ester-forming derivative thereof, and then this is polycondensed, which is a method for producing a polyester.

In the case of polyester obtained by using crystalline germanium dioxide having an alkali metal content of more than 100 ppm, the transparency of the obtained hollow molded article becomes very poor, and the degree of crystallinity of the mouth plug is reduced. Fluctuation becomes large and the size of the spigot part does not pass the standard. As a result, the capping of the spout becomes defective and the contents leak and the commercial value is lost.

The crystalline germanium dioxide in the present invention is hexagonal type germanium dioxide, and is used as a powder or a slurry of ethylene glycol, a solution dissolved in water by heating or a solution obtained by adding ethylene glycol to the solution and subjecting it to heat treatment. Although it is used in the production of the polyester, it is preferable to use it as a solution in which germanium dioxide is dissolved by heating in water, or a solution in which ethylene glycol is added and heated.

These catalyst solutions are added during the transesterification step or after the end of the transesterification reaction until the start of the polycondensation reaction, or during the esterification step or during the step between the end of the esterification reaction and the start of the polycondensation reaction. be able to. The amount used is 10 to 150 ppm, preferably 13 to 10 as the residual Ge amount in the polyester.
It is 0 ppm, more preferably 15 to 70 ppm.

Further, in the method for producing a polyester of the present invention, when the crystalline germanium dioxide having the above characteristics is used as a polycondensation catalyst, Mg, Al, Si, Ti, M
n, Fe, Co, Zn, Ga, Sr, Zr, Sn, S
It is preferable to coexist a compound containing at least one element selected from the group consisting of b, W and Pb.

Mg, Al, Si, T used in the present invention
i, Mn, Fe, Co, Zn, Ga, Sr, Zr, S
Examples of the compound containing at least one element selected from the group consisting of n, Sb, W, and Pb include saturated aliphatic carboxylic acid salts such as acetates of these elements, and unsaturated aliphatic carboxylic acids such as acrylates. Salts, aromatic carboxylic acid salts such as benzoic acid, halogen-containing carboxylic acid salts such as trichloroacetic acid, hydroxycarboxylic acid salts such as lactate salts, inorganic acid salts such as carbonate salts, organic sulfonic acid salts such as 1-propanesulfonic acid salts Salt, organic sulfates such as lauryl sulfate, oxides,
Examples thereof include chelate compounds with hydroxides, chlorides, alkoxides, acetylacetonates, etc., powders, aqueous solutions,
It is added to the reaction system as an ethylene glycol solution, a slurry of ethylene glycol or the like.

Among these, magnesium acetate, magnesium nitrate, magnesium chloride, magnesium oxide, magnesium methoxide and the like are preferably used as the magnesium (Mg) compound, and among them, magnesium acetate tetrahydrate is particularly preferable.

As the aluminum (Al) compound, specifically, aluminum formate, aluminum acetate, basic aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum laurate, aluminum stearate, aluminum benzoate, Carboxylates such as aluminum trichloroacetate, aluminum lactate, aluminum citrate, aluminum salicylate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, polyaluminum chloride, aluminum nitrate, aluminum sulfate, aluminum carbonate, aluminum phosphate, phosphonic acid Inorganic acid salts such as aluminum, aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum iso-pro Aluminum chelate compounds such as alkoxide, aluminum n-butoxide, aluminum t-butoxide, etc., aluminum alkoxide, aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum. Examples thereof include organoaluminum compounds and partial hydrolysates thereof, aluminum oxide and the like. Among these, carboxylates, inorganic acid salts and chelate compounds are preferable, and among these, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferable.

As the titanium (Ti) compound, tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetra-n-butyl titanate and the like, and their compounds. Partial hydrolyzate, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate,
Calcium titanyl oxalate, titanyl oxalate compounds such as strontium titanyl oxalate, titanium trimellitate, titanium sulfate, titanium chloride and the like are preferable, and among these, tetraisopropyl titanate, tetra-n-butyl titanate, titanyl ammonium oxalate, Preference is given to potassium titanyl oxalate.

As the manganese (Mn) compound, it is preferable to use fatty acid manganese salts such as manganese acetate, manganese carbonate, manganese nitrate, manganese chloride, manganese acetylacetonate, manganese naphthenate and their hydrates, among which. Manganese acetate tetrahydrate is particularly preferred.

As the cobalt (Co) compound, cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt chloride,
Preference is given to using cobalt acetylacetonate, cobalt naphthenate and their hydrates, among which cobalt acetate tetrahydrate is particularly preferred.

As the zinc (Zn) compound, it is preferable to use a zinc salt of fatty acid such as zinc acetate, zinc carbonate, zinc nitrate, zinc chloride, zinc acetylacetonate, zinc naphthenate and hydrates thereof. Zinc acetate tetrahydrate is particularly preferred.

Examples of the tin (Sn) compound include dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditinoxide, triethyltin hydroxide, monobutylhydroxytin oxide, triisobutyltin adate, diphenyltin dilaurate and monobutyltin. Trichloride,
Dibutyltin sulfide, dibutylhydroxytin oxide, methylstannonic acid, ethylstannonic acid and the like are preferable, and monobutylhydroxytin oxide is particularly preferable.

As the antimony (Sb) compound, antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, triphenyl antimony and the like are preferable, and among them, antimony is particularly preferable. Glycolate is preferred.

These metal compounds can be added to the reaction system at any stage of the polymerization reaction. For example, it can be added to the reaction system at any stage before and during the esterification reaction or transesterification reaction or immediately before the polycondensation reaction or at any stage during the polycondensation reaction.

The amount of the compound containing at least one element described in claim 2 is 0.0001 to 0.3 mol%, preferably 0.001 to 0.3 mol% as the residual amount of the element with respect to the acid component of the polyester. It is preferably 0.2 mol%, more preferably 0.005 to 0.1 mol%.

When the above range is satisfied, it is possible to obtain a polyester having a good color tone, having a suitable crystallization rate, and giving a molded article with little fluctuation in crystallization rate. The content of the compound containing these elements is 0.0001
If it is less than mol%, the crystallization promoting effect will be poor, and if the crystallization cycle time of the plug part is shortened in order to increase the productivity and reduce the cost during molding, the plug part of the hollow molded part Due to insufficient crystallization, the amount of shrinkage of the spout does not fall within the specified value range, resulting in poor capping and leakage of the contents. On the other hand, if it exceeds 0.3 mol%, the crystallization rate becomes too fast and the crystallization of the plug part of the hollow molded article becomes excessive, so that the shrinkage / shrinkage amount of the plug part does not fall within the specified value range. Therefore, the capping becomes defective and the content leaks, and the preform for the hollow molded body is whitened, which makes normal stretching impossible.

In the method for producing polyester of the present invention, the sodium content (N), the magnesium content (M), the silicon content (S) and the calcium content (C) are as follows: ) To (4), it is preferable to perform chip formation of the melt polycondensed polyester while cooling with cooling water satisfying at least one, and preferably all of them. N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4)

The sodium content (N) in the cooling water is preferably N ≦ 0.5 ppm, more preferably N
≦ 0.1 ppm. The magnesium content (M) in the cooling water is preferably M ≦ 0.3 ppm, more preferably M ≦ 0.1 ppm. The content (S) of silicon in the cooling water is preferably S ≦ 0.5 ppm, more preferably S ≦ 0.3 ppm. Further, the calcium content (C) in the cooling water is preferably C ≦ 0.5 ppm, more preferably C ≦ 0.1.
It is ppm.

Further, the lower limits of sodium content (N), magnesium content (M), silicon content (S) and calcium content (C) in the cooling water are N ≧
0.001ppm, M ≧ 0.001ppm, S ≧ 0.0
2 ppm and C ≧ 0.001 ppm. In order to make it below such a lower limit value, enormous capital investment is required, and the operating cost becomes very high, so that economical production is difficult.

The content of sodium (N), the content of magnesium (M), the content of silicon (S) and the content of calcium (C) are at least one of the above (1) to (4). The transparency of the molded product from the melt polycondensed polyester chip-formed while cooling with cooling water satisfying the above condition or the polyester solid-phase polymerized with this is very excellent. When using cooling water that deviates from the above conditions, these metal-containing compounds adhere to the polyester chip surface, the crystallization rate of the final polyester obtained is very fast, and its fluctuation becomes large, Also, only polyester containing foreign substances containing these metals can be obtained,
Not preferable. The content of the metal in the industrial water fluctuates considerably throughout the year, and the content of the metal adhering to the polyester fluctuates according to this fluctuation, or at least one of the above (1) to (4). As compared with the case where cooling water satisfying the above conditions is used, the transparency of the molded product from the polyester obtained by using industrial water as the cooling water at the time of chip formation is poor, and its fluctuation is very large. In addition, it is preferable that all of the above (1) to (4) are satisfied.

When solid-phase polymerizing the molten polycondensed polyester chipped while cooling with cooling water that deviates from the above conditions, it is attached to the chip surface in the chipping step and brought into the solid-state polymerization reactor. The above-mentioned metal-containing substance adheres to the vessel wall of the solid-state polymerization apparatus together with a part of the surface layer of the polyester chip, and when this is heated for a long time at a high temperature of about 170 ° C. or higher, a scale having a high metal content is obtained. And adhere to the vessel wall. Then, it sometimes peels off and mixes into the polyester chip, and becomes foreign matter in the molded body such as a bottle, which may reduce the commercial value.

When a sheet or film is produced, the scale is clogged with the molten polymer filtration filter at the time of film formation, so that the filtration pressure of the filter increases sharply, resulting in operability and productivity. The problem arises that is worse.

A method for suppressing the sodium content, magnesium content, silicon content, and calcium content in the cooling water of the chips to the above ranges will be illustrated below, but the present invention is not limited to this.

In order to reduce sodium, magnesium, calcium and silicon in the cooling water, a device for removing sodium, magnesium, calcium and silicon is installed at least at one or more places in the process until industrial water is sent to the chip cooling process. To do. A filter is installed to remove clay minerals such as particulate silicon dioxide and aluminosilicate. As an apparatus for removing sodium, magnesium, calcium and silicon, an ion exchange apparatus,
Examples include an ultrafiltration device and a reverse osmosis device.

Further, 500 particles having a particle size of 1 to 25 μm existing in water introduced from outside the system as chip cooling water are used.
It is desirable to use water made up to 100 pieces / 10 ml or less. The number of particles having a particle size of 1 to 25 μm in the cooling water is preferably 10,000 particles / 10 ml or less, more preferably 1000 particles / 10 ml or less. Particle size in introduced water 25
The number of particles exceeding μm is not particularly limited, but preferably 2000 particles / 10 ml or less, more preferably 5 particles.
00 pieces / 10 ml or less, more preferably 100 pieces / 1
0 ml, particularly preferably 10 pieces / 10 ml or less.

The particles having a particle size of less than 1 μm in the introduced water are not particularly specified in the present invention, but in order to obtain a transparent molded product or a polyester which gives a molded product having an appropriate crystallization rate. The smaller the number, the better. Particle size 1
The number of particles less than μm is preferably 100,000 /
10 ml or less, more preferably 50,000 pieces / 10 ml
Or less, more preferably 20,000 pieces / 10 ml or less,
Particularly preferably, it is 10,000 pieces / 10 ml or less. 1
As a method for removing and controlling particles having a size of μm or less from water, a microfiltration method or an ultrafiltration method using a membrane such as a ceramic membrane or an organic membrane can be used.

50,000 particles / 10 ml of particles having a particle size of 1 to 25 μm in the introduced water to be introduced in the chip forming step below.
The control method is illustrated below, but the present invention is not limited to this.

The number of particles in the introduced water is 50,000 / 10 m
As a method of reducing the particle size to 1 or less, an apparatus for removing particles is installed at at least one place until natural water such as industrial water is supplied to the chip forming step. Preferably, a device for removing particles is installed between the natural water sampling port and the chipping step, and the content of particles having a particle size of 1 to 25 μm in water supplied to the chipping step is set. 50,000 pieces /
It is preferably 10 ml or less. As a device for removing particles, a filter filtration device, a membrane filtration device, a settling tank,
A centrifugal separator, a foam entrainment processing machine, etc. are mentioned. For example, in the case of a filter filtration device, examples thereof include a belt filter system, a bag filter system, a cartridge filter system, a centrifugal filtration system and the like. Among them, a belt filter type, a centrifugal filtration type, and a bag filter type filtration device are suitable for continuous operation. Further, in the case of a belt filter type filtering device, examples of the filter material include paper, metal, cloth and the like. Further, the size of the mesh of the filter is 5 to 100 μm, preferably 10 to 70 μm, and more preferably 15 to 40 μm in order to efficiently remove particles and efficiently introduce water.

Further, it is preferable to use the cooling water for the chips while repeatedly recycling them, from the viewpoint of improving economy and productivity. A filter, a temperature controller, a device for removing impurities such as acetaldehyde, and the like can be provided during the cooling water recycling process. Further, a device for removing the above particles, sodium, magnesium, calcium, and silicon can be provided.

In the chip forming step, the melt polycondensed polyester is extruded into the water through the pores of the die and cut in the water, or is extruded into the air and immediately cut while cooling with cooling water. Chiped by etc.

In the manufacturing method of the present invention, the shape of the polyester chips may be any of cylinder type, square type, spherical type or flat plate type. Its average particle size is usually 1.5
˜5 mm, preferably 1.6 to 4.5 mm, more preferably 1.8 to 4.0 mm. For example, in the case of a cylinder type, the length is 1.5 to 4 mm and the diameter is 1.5.
It is practically about 4 mm. In the case of spherical particles, it is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. Further, it is practical that the weight of the chip is in the range of 10 to 30 mg / piece.

The polyester melt-polycondensed as described above is formed into chips, and then, in a transportation pipe, a filling process for forming a silo for storage, a filling container for transportation / storage such as a flexible container, a molding process and the like will be described later. It is transported to a subsequent step such as a contact treatment step with water or a solid phase polymerization step. When such chips are transported by, for example, a forced low-density transportation method using air, a large impact force is applied to the surface of the molten polycondensed polyester chips due to the collision with the pipe, and as a result, fine or film is produced. A large amount of particles are generated. Such fine or film-like material has the effect of promoting the crystallization of polyester, and when it is present in a large amount, the transparency of the obtained molded product becomes extremely poor. In addition, such fines and film-like materials,
Those having a melting point higher than the normal melting point by about 10 to 20 ° C. or more are included. Further, when a melt polycondensed polyester chip is used with a feeder that is subjected to impact force or shear force, a very large amount of fines or film-like substances having a melting point higher than the normal melting point by about 10 to 20 ° C. or more are generated. . this is,
It is presumed that the chip may generate heat due to a large force such as an impact force applied to the chip surface, and at the same time, oriented crystallization of polyester may occur on the chip surface, resulting in a dense crystal structure.

About 10 to 20 above the normal melting point
When melt-polycondensed polyester fine or film-like material having a melting point higher than ℃ is subjected to solid-state polymerization treatment together with melt-polycondensed polyester chips, and subsequently subjected to treatment such as contact treatment with water described below, these melting points are treated. It will be even higher than before. Even fine or film-like materials having a melting point not higher than the normal melting point by about 10 ° C. or higher, the melting point of the fine or film-like material is about 1% higher than the normal melting point.
It has a high melting point of 0 to 20 ° C or more. It is presumed that this is because the crystal structure is changed to a more dense crystal structure by these treatments. Such a fine or film-like material also has an effect of promoting crystallization of polyester, and when it is present in a large amount, the transparency of the obtained molded product becomes very poor.

In the present invention, the melting point of chips, fine particles, etc. is measured by the following method using a differential scanning calorimeter (DSC). The melting peak temperature of DSC is called the melting point. The melting peak representing this melting point is composed of one or more melting peaks. In the present invention, when there is one melting peak, the peak temperature is
When there are a plurality of melting peaks, the melting peak temperature on the highest temperature side among the plurality of melting peaks is defined as "the peak on the highest temperature side of the fine melting peak temperature". In the examples, etc., it is referred to as "melting temperature of fine".

In general, the melt polycondensed polyester and the solid-phase polyester described later depend on the production method, but some fine or film-like substances having a melting point higher than the normal melting point by about 10 to 20 ° C. or more as described above. About 1 including fine
It is contained in an amount of about 00 ppm to about several wt% and, moreover, such fines are not present in the melt polycondensed polyester chips in a uniform mixed state but are unevenly distributed. Therefore, in the method for producing a polyester of the present invention, a device for removing fines and / or film-like substances is added after the chip forming step,
The above problems can be solved by setting the content of at least one of the fine content, the film-like material content, or the total content of the fine content and the film-like material content of the melt polycondensed polyester to 5000 ppm or less. It is a solution.

The fine content, the film content, or the total content of the fine content and the film content of the melt-polycondensed polyester is preferably 30.
00 ppm or less, more preferably 1000 ppm or less,
More preferably 500 ppm or less, most preferably 1
It is desirable to reduce it to 00 ppm or less. As will be described later, when supplied to the solid phase polymerization step or the water treatment step, it is preferably 500 ppm or less.

As a method for removing fines, etc., a vibrating screen step and an air flow which are separately installed between the above chipping step and the subsequent step such as the step of filling the storage silo and the solid phase polymerization step are used. Examples include a method of treating with an airflow classifier, a gravity type classifier, and the like. You may add these processes further.

Further, the solid-phase polymerized polyester is filled in a transportation pipe in a transportation / storage filling container such as a storage silo or a flexible container after a molding step or a contact treatment step with water described later. Transported to the process. When such chips are transported by a forced low-density transportation method using air, for example, like the above-mentioned melt polycondensation polyester chips, the surface of the solid-phase-polymerized polyester chips is collided with a pipe by collision. A large impact force is applied, and as a result, a large amount of fines and film-like substances are generated as in the case of the melt polycondensed polyester. Such a fine or film-like substance has the effect of promoting crystallization of the polyester as in the case of the polyester after the melt polycondensation, and when it is present in a large amount, the transparency of the obtained molded product is improved. Becomes very bad. In addition, such fines and film-like materials have a melting point of about 10 to 20 from the normal melting point.
Those having a melting point higher than ℃ are included. Also, when solid-phase polymerization is performed using a rotary solid-state polymerization apparatus, or when a feeder that applies impact force or shearing force to the solid-state polymerization polyester chip is used, the melting point is about 10 to 10% higher than the normal melting point.
An extremely large amount of fines and film-like substances having a melting point higher than 20 ° C. are generated. The reason for the high melting point is the above-mentioned.

About 10 to 20 ° C. from the normal melting point
When the solid-phase polymerized polyester containing the fine or film-like material having a high melting point is molded under normal molding conditions, such a high melting point crystal is not completely melted during melt molding and remains as a crystal nucleus. As a result, the crystallization rate at the time of heating becomes very fast, and the crystallization of the plug part of the hollow molding container becomes excessive, so that the shrinkage amount of the plug part does not fall within the specified value range, and The problem of capping failure and leakage of contents occurs. In addition, the preform for hollow molding is whitened, which makes normal stretching impossible,
Since the thickness unevenness occurs and the crystallization speed is high, the transparency of the obtained hollow molded article is deteriorated, and the fluctuation of the transparency becomes large, which is a problem.

In the case where the polyester according to the present invention is polyethylene terephthalate, when it is transported to the storage silo or the like by the forced transportation method through the above chip forming step, the melting peak temperature is changed. The melting peak temperature on the highest temperature side is 2
Fines and film-like substances above 65 ° C are sometimes included. Further, when the fine and / or film-like material contained in the melt polycondensed polyester supplied to the solid phase polymerization step has a melting peak temperature on the highest temperature side of the melting peak temperature of more than 265 ° C., The solid-state polymerized PET obtained in the solid-state polymerization step contains fines and film-like substances whose melting peak temperature on the highest temperature side of the melting peak temperature considerably exceeds 265 ° C. For the above-mentioned reason, the crystallization rate of the molded product from such solid-phase-polymerized polyester becomes too fast, or its fluctuation becomes extremely large, and the obtained preforming product for hollow molding is whitened, Normal stretching may not be possible, thickness unevenness may occur, the transparency of the obtained hollow molded article may deteriorate, and the transparency may fluctuate significantly, which may be a serious problem.

As a method for preventing the melted polyester or the solid-phase-polymerized polyester from containing fine and / or film-like substances whose melting peak temperature on the highest side of the melting peak temperature exceeds 265 ° C. For example, the following method may be mentioned. That is, after the melt polycondensation, the polyester melted from a die is extruded into water and cut in water, or extruded into the atmosphere and immediately cut with cooling water to be cut into chips, and then formed into chips. After draining the melted polycondensed polyester chips that have been removed, chips, fines, and film-like substances of shapes other than the prescribed size are removed by a vibrating screen device and an airflow classifier using an air flow, and a plug transport method or bucket type conveyor-transport method is used. Send to storage tank. The chips are taken out from the tank by a screw type feeder, and transported to the next step by a plug type transportation system or a bucket type conveyor type transportation system. Further, in the case of subsequent solid-phase polymerization, a fine removal treatment is performed immediately before the solid-phase polymerization step by providing an air stream classifier with an air stream, a vibration type sieving unit, or the like. Further, the melt polycondensed polyester that has been subjected to the fine or film-like matter removal treatment,
It is also possible to directly remove fines or film-like substances by using an air stream classifier with an air stream, a vibrating type sieving device or the like immediately before the solid phase polymerization step, and directly feed the solid phase polymerization step. When transporting melt-polycondensed polyester chips to a solid-state polymerization facility or when transporting polyester chips after solid-state polymerization to a sieving process or a storage tank, most of these transports are plug transport or bucket type. Adopting a conveyor transportation method, and using a screw feeder to extract chips from the crystallization device or solid-state polymerization reactor.
Use a device that can minimize the impact between the chip and the process equipment or transportation piping.

Therefore, the polyester subjected to the solid phase polymerization treatment in the solid phase polymerization step is transported to a fine removing device for separating and removing fines and / or film-like substances, and before the subsequent step as described above, It is important to remove as much of these as possible.

That is, in the polyester production method of the present invention, the fine polycondensation polyester and / or the film-like substance contained in the melt polycondensation polyester supplied in the solid phase polymerization step and / or the solid phase polymerization polyester supplied in the subsequent step are contained. Content, or at least one of the total content of the fine content and the film-like material content is 50
By setting the content to 0 ppm or less, the above problems are solved.

According to the method for producing a polyester of the present invention, the intrinsic viscosity is 0.55 to 1.50 deciliter / gram, the acetaldehyde content is 10 ppm or less, and the cyclic 3
When the content of the monomer is 0.5% by weight or less, the haze of the molded plate having a thickness of 5 mm obtained by injection molding is 15% or less, and the molded plate having a thickness of 2 mm obtained by injection molding is heated. The crystallization temperature (Tc1) is 150 to 175 ° C., and the number of spherulites generated when the formed plate is heated and crystallized is 2 × 10 ⁹ to 15 × 1.
It is possible to obtain a polyester having ethylene terephthalate as the main repeating unit in the range of ⁰⁹ units / m ² .

The intrinsic viscosity of the polyester having ethylene terephthalate as the main repeating unit obtained by the production method of the present invention has an intrinsic viscosity of 0.55 to 1.50 deciliter / gram, preferably 0.60 to 1.30 deciliter / gram. , And more preferably 0.70 to 1.00
It is in the deciliter / gram range. Intrinsic viscosity is 0.5
If it is less than 5 deciliters / gram, the mechanical properties of the obtained molded article and the like are poor. On the other hand, if it exceeds 1.50 deciliters / gram, the resin temperature becomes high during melting by a molding machine or the like, resulting in severe thermal decomposition, increasing the amount of free low molecular weight compounds that affect the aroma retention, Will be colored yellow.

Further, the acetaldehyde content of the polyester obtained by the production method of the present invention whose main repeating unit is ethylene terephthalate has an acetaldehyde content of 10 ppm.
Or less, preferably 8 ppm or less, more preferably 5 pp
m or less, and the formaldehyde content is 7 ppm or less, preferably 6 ppm or less, more preferably 4 ppm or less. If the acetaldehyde content exceeds 10 ppm or if the formaldehyde content disappears below 7 ppm,
The flavor, smell and the like of the contents such as molded articles obtained from such polyesters are deteriorated.

Further, the amount of diethylene glycol copolymerized with the polyester whose main repeating unit is ethylene terephthalate obtained by the production method of the present invention is 1.
0-5.0 mol%, preferably 1.3-4.5 mol%,
More preferably, it is 1.5 to 4.0 mol%. If the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability will be poor and the molecular weight will drop significantly during molding.
Further, the acetaldehyde content and the formaldehyde content increase undesirably. If the content of diethylene glycol is less than 1.0 mol%, the transparency of the obtained molded product will be poor.

Further, the content of the cyclic trimer of the polyester whose main repeating unit is ethylene terephthalate obtained by the production method of the present invention is 0.5% by weight or less, preferably 0.45% by weight or less, more preferably Is 0.40% by weight or less. When a heat-resistant hollow molded article or the like is molded from the polyester of the present invention, heat treatment is carried out in a heating mold, but when the content of the cyclic trimer is 0.5% by weight or more, the heating mold is heated. Adhesion of oligomers to the surface sharply increases, and the transparency of the obtained hollow molded article is extremely deteriorated.

The haze of a molded plate obtained from the polyester whose main repeating unit is ethylene terephthalate obtained by the production method of the present invention is preferably 10.
% Or less, more preferably 8% or less, and the crystallization temperature (Tc1) during heating is preferably 155 to 173.
C., more preferably 158 to 170.degree.

When the haze of the molded plate exceeds 15%,
The obtained hollow molded article has poor transparency, which is a problem particularly in the case of a stretched hollow molded article. Also, Tc1 is 175 ° C
When it exceeds, the heating crystallization rate becomes very slow, the crystallization of the plug portion of the hollow molded body becomes insufficient, and the problem of leakage of the contents occurs. Further, when Tc1 is less than 150 ° C., the transparency of the hollow molded article decreases, which becomes a problem.

Furthermore, a thickness of 3 mm obtained by melt injection molding of a polyester whose main repeating unit is ethylene terephthalate obtained by the production method of the present invention.
The number of spherulites generated when the test piece from the molded body of No. 1 is crystallized at elevated temperature is in the range of 2 × 10 ⁹ to 15 × 10 ⁹ pieces / m ² , preferably 3 × 10 ^{9 to} 12 × 10 ^9. range of pieces / m ^2, and more preferably 3 × 10 ⁹ ~10 × 10 ⁹ pieces / m ²
It is preferably in the range of.

In order to produce polyester having a spherulite number less than 2 × 10 ⁹ pieces / m ² , there are many problems such as high equipment cost and very poor productivity. The spherulite number is 15
When it exceeds × 10 ⁹ pieces / m ² , the transparency of the heat-resistant hollow molded article decreases, and the transparency becomes a problem especially in a large hollow molded article of 1.5 liters or more.

Here, the number of spherulites at the time of temperature crystallization of the molded product for specifying the polyester of the present invention is the thermomechanical analysis (TMA), type TM manufactured by Mac Science Co., Ltd.
The molded plate was heat-treated using A4000S and measured by the method described below.

Polyester is a mold stain caused by cyclic oligomers and linear oligomers such as cyclic dimers and cyclic trimers adhering to the inner surface of the mold, the gas exhaust port of the mold, and the exhaust pipe during molding. In order to prevent such problems, contact treatment with water can be carried out after the solid phase polymerization.

The effect of such a contact treatment with water is that, in the case of a polyester whose main repeating unit is ethylene terephthalate, it is cyclic after being melted at 290 ° C. for 60 minutes in a nitrogen atmosphere by the following method. Determined by the trimer increase amount (ΔCT amount), the cyclic trimer increase amount (ΔCT amount) is 0.50% by weight or less, preferably 0.30% by weight or less, and more preferably 0.10% by weight.
The following is desirable. A method of contact-treating the above polyester chips with water, steam or a gas containing steam will be described below.

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

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

When the polyester chips are subjected to water treatment in a batch system, a silo type treatment tank can be used. That is, the polyester chips are received in silos in a batch system and treated with water. When the polyester chips are treated with water continuously, the polyester chips can be continuously or intermittently received from the upper portion of the tower-type treatment tank for water treatment.

Whether the water treatment method is a continuous system or a batch system, the number of particles having a particle size of 1 to 25 μm existing in water introduced from outside the system is X,
The content of sodium is N, the content of magnesium is M,
When the content C of calcium is S and the content of silicon is S, at least one of the following (5) to (9) is satisfied and water treatment is performed. 1 ≤ X ≤ 50,000 (pieces / 10 ml) (5) 0.001 ≤ N ≤ 1.0 (ppm) (6) 0.001 ≤ M ≤ 0.5 (ppm) (7) 0.001 ≤ C ≤ 1 0.0 (ppm) (8) 0.01 ≤ S ≤ 2.0 (ppm) (9)

By setting any of the number of particles in the water introduced into the water treatment tank and the content of sodium, magnesium, calcium or silicon within the above range, a metal such as an oxide or hydroxide called a scale is set. The contained substance floats or precipitates in the treated water, or even adheres to the walls of the processing tank or piping, which adheres to and permeates the polyester chips, promotes crystallization during molding, and makes bottles with poor transparency. Can be prevented.

The number of particles in water introduced into the water treatment tank is 500
At least one of the steps up to the supply of natural water such as industrial water to the treatment tank is carried out as a method of reducing the number to 100 pieces / 10 ml or less.
Install devices to remove particles at more than one place. Preferably from the natural water sampling port, to the treatment tank described above, a pipe for returning the water drained from the treatment tank to the treatment tank again, a fine removal device, and the like, to a treatment device including incidental equipment necessary for water treatment An apparatus for removing particles is installed between them, and the content of particles having a particle size of 1 to 25 μm in water supplied to the processing apparatus is set to 1 to 5
It is preferable that the number is 0000 pieces / 10 ml or less. As a device for removing particles, the same device as that used for removing particles in chip cooling water can be mentioned.

In order to reduce sodium, magnesium, calcium and silicon in the water introduced into the water treatment tank, at least one or more of sodium and magnesium are added in the process until natural water such as industrial water is supplied to the treatment tank.
Install a device to remove calcium and silicon. Examples of these devices include the same devices as those used for the treatment of chip cooling water.

Whether the water treatment method is continuous or batchwise, if all or most of the treated water discharged from the treatment tank is treated as industrial wastewater, a large amount of new water can be used. Not only that, but there is concern that the increase in the amount of wastewater will have an impact on the environment. That is, by returning at least a part of the treated water discharged from the treatment tank to the water treatment tank and reusing it, it is possible to reduce the necessary amount of water, and it is possible to reduce the effect on the environment due to the increase in the amount of drainage. If the wastewater returned to the water treatment tank maintains a certain temperature,
Since the heating amount of the treated water can be reduced, it is preferable that the treated water discharged from the treated layer be returned to the water treated layer and reused. Further, by reusing the water, the flow rate of the treated water in the treated layer can be increased, and as a result, the fines and film-like substances attached to the polyester chips can be washed off, so that an effect of removing the fines is also produced. Here, as the treated water which is discharged from the water treatment tank and then returned to the treatment tank and reused, the overflow of the water treatment tank is used.
There are water discharged from the mouth and treated water discharged from the treatment tank together with the polyester chips, and then separated from the chips.

However, in the treated water discharged from the treatment tank in the water treatment, the fine or film-like substances already attached to the polyester chips at the stage of receiving the polyester chips in the treatment tank, the polyester chips themselves or the treated water during the water treatment are treated. It contains polyester fines and film-like substances that are generated by friction with the tank wall. In addition, the new treated water contains fine particles derived from inorganic substances, spoiled plants, and organic fine particles derived from animals.

Therefore, when the treated water discharged from the treatment tank is returned to the treatment tank and reused, the amount of fines and fine particles contained in the treated water in the treatment tank gradually increases, and the amount of fines contained in the treated water increases. In some cases, film-like substances and fine particles adhered to the wall of the processing tank and the wall of the pipe and clog the pipe.

Fine, film-like substances and fine particles contained in the treated water adhere to the polyester chip, and then fine and film-like substances and fine particles adhere or permeate the polyester chip at the stage of drying and removing water. Therefore, the content of fine, film-like and fine particles of the polyester becomes very large, the crystallinity of the polyester thus obtained is promoted, and the transparency of the obtained bottle becomes poor, and the bottle mouth The crystallinity at the time of crystallization of the plug part becomes excessive and the size of the mouth plug part does not meet the standard,
As a result, capping of the spigot part and leakage of the contents may occur.

Therefore, in the present invention, the fine content of polyester to be supplied or filled in the water treatment layer,
The content of the film-like material or the total content of the fine content and the film-like material content is about 50.
It is preferable to solve the above problems by limiting the amount to 0 ppm or less, preferably 300 ppm or less, and more preferably 100 ppm or less. If the content of fines, etc. exceeds 500ppm, the content of fines, etc. in the treated water in the treatment tank will rapidly increase, which may clog the pipes, and the amount of fines attached to the treated polyester chips may increase. The crystallinity is promoted by the influence of fines, and only bottles with poor transparency can be obtained.

A method for reducing the content of polyester fines or film-like substances to be added to the water treatment tank is as follows.
For example, a method of passing a polyester chip after solid-phase polymerization through a sieving process or a removing process such as fines by an air flow can be mentioned.

In the present invention, after being discharged from the water treatment tank, at least a part of the water is returned to the treatment tank to be reused. 10 ml or less, preferably 800
It is desirable that the number is maintained at 00 pieces / 10 ml or less, and more preferably at 50,000 pieces / 10 ml or less. Here, the treated water thus returned to the treatment tank and reused is referred to as recycled water.

Below, the particle size of the recycled water is from 1 to 4
A method of reducing the number of particles of 0 μm to 100,000 particles / 10 ml or less is illustrated, but the present invention is not limited to this. The number of particles having a particle size of 1 to 40 μm in the recycled water is 1000
As a method for reducing the number of particles to 100 pieces / ml or less, an apparatus for removing fines and fine particles is installed at at least one place in the process until the treated water discharged from the treating tank is returned to the treating tank again. Examples of the device for removing fines and fine particles include a filter-filtration device, a membrane filtration device, a settling tank, a centrifuge, and a foam entrainment treatment device. For example filter
Examples of the filtration device include automatic self-cleaning system, belt filter system, bag filter system, cartridge filter system, and centrifugal filtration system. Among them, a belt filter type, a centrifugal filtration type, and a bag filter type filtration device are suitable for continuous operation. Further, in the case of a belt filter type filtering device, examples of the filter material include paper, metal, cloth and the like. Further, in order to remove fines and to efficiently flow the treated water, the size of the mesh of the filter is 5 to 100 μm, preferably 5 to 70 μm.
μm, more preferably 5 to 40 μm.

Further, the water introduced from outside the system can be discharged from the water treatment tank together with the chips and then supplied to the treatment tank together with the treated water which is reused after being subjected to treatment such as filtration. is there.

When the treatment is carried out by contacting the polyester chips with steam or a steam-containing gas, 50 to 50
Water vapor or water vapor-containing gas or water vapor containing water at a temperature of 150 ° C., preferably 50 to 110 ° C. is preferably fed or present in an amount of 0.5 g or more as water vapor per kg of granular polyester, or the presence of granular polyester and water vapor. Contact with.

The contact between the polyester chips and steam is usually 10 minutes to 2 days, preferably 20 minutes.
It will be held for 10 hours.

The method of industrially carrying out the contact treatment between the granular polyester and steam or a gas containing steam will be illustrated below, but the method is not limited to this. Further, the treatment method may be either a continuous method or a batch method.

When the polyester chips are subjected to the contact treatment with steam in a batch system, a silo type treatment apparatus can be used. That is, the polyester chips are received in a silo, and steam or a steam-containing gas is supplied in a batch method to perform contact treatment.

In the case where the polyester chips are continuously contact-treated with steam, it is possible to continuously receive the granular polyester from the upper part in a tower-type processing apparatus and continuously supply steam in a cocurrent or countercurrent for contact treatment with steam. it can.

Also in the case of the contact treatment with steam or steam-containing gas, either the fine content of the polyester chip before the treatment, the film-like material content, or the total content of the fine content and the film-like material content is used. It is desirable to reduce the content to about 500 ppm or less as in the case of the water treatment.

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

For drying the polyester chips that have been contact-treated with water or steam, a commonly used polyester drying process can be used. As a method for continuously drying, a hopper-type aeration dryer in which polyester chips are supplied from the upper part and a drying gas is aerated from the lower part is usually used.

As a dryer for drying in a batch system, drying may be carried out under atmospheric pressure while ventilating a drying gas.

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

In the present invention, the polyester thus dried is passed through a sieving step or a step of removing fines, etc. by an air stream in the same manner as described above to obtain a fine content of polyester, a film-like content, or Either of the total content of the fine content and the content of the film-like material is about 500 ppm or less, preferably 300 p
It is desirable to limit to pm or less, more preferably 100 ppm or less.

[0121] In the hollow molded article, the plug portion is heated and crystallized depending on the application. However, it may be difficult to control the crystallization due to variations in molding conditions and heating conditions. May occur. In order to solve such a problem, in the production method of the present invention, it is desirable that at least one resin selected from the group consisting of a polyolefin resin, a polyamide resin, and a polyacetal resin is blended with the polyester. The compounding ratio of the above-mentioned polyolefin resin is 0.1 ppb.
~ 50,000 ppm, preferably 0.3 ppb-100
00 ppm, more preferably 0.5 ppb to 100 pp
m, more preferably 1.0 ppb to 1 ppm, particularly preferably 1.0 ppb to 45 ppb. If the compounding amount is less than 0.1 ppb, the crystallization speed will be very slow and the mouthpiece of the hollow molded article will not be sufficiently crystallized. Therefore, if the cycle time is shortened, the amount of shrinkage of the mouthpiece will be regulated. Capping failure occurs because it does not fall within the value range, and the stretch heat-fixing mold for molding the heat-resistant hollow molded product is heavily contaminated, and the mold is frequently cleaned when trying to obtain a transparent hollow molded product. There must be. Also 50,000p
If it exceeds pm, the crystallization speed becomes fast, and the crystallization of the plug part of the hollow molded body becomes excessive, so that the shrinkage / shrinkage amount of the plug part does not fall within the specified range, resulting in poor capping. Of the hollow molded body and the preformed body for the hollow molded body is whitened, which makes normal stretching impossible. Further, in the case of a sheet-like material, if it exceeds 50,000 ppm, the transparency becomes extremely poor and the stretchability becomes poor so that normal stretching is impossible, and only a stretched film with large thickness unevenness and poor transparency is obtained. I can't. Further, when the above-mentioned polyolefin resin or the like is used alone, it is hardly effective in preventing stains on the heating die, but it has been found that coexistence with a specific amount of fine is very effective on stains on the die.

In the method for producing polyester of the present invention, the polyolefin resin blended with the polyester may be polyethylene resin, polypropylene resin, or α-olefin resin. Further, these resins may be crystalline or amorphous.

In the method for producing polyester of the present invention, examples of the polyethylene-based resin blended with the polyester include ethylene homopolymer, ethylene and propylene, butene-1,3-methylbutene-1, pentene-1, Other α having about 2 to 20 carbon atoms such as 4-methylpentene-1, hexene-1, octene-1, and decene-1
-Copolymers with olefins and vinyl compounds such as vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, and styrene can be mentioned. Specifically, for example, low / medium / high density polyethylene (branched or linear) ethylene homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-methyl, etc. Pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer,
Examples thereof include ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, ethylene-ethyl acrylate copolymers, and other ethylene-based resins.

Further, in the method for producing a polyester of the present invention, examples of the polypropylene resin blended with the polyester include a homopolymer of propylene, propylene and ethylene, butene-1,3-methylbutene-1,
Pentene-1,4-methylpentene-1, hexene-
Other α-olefins having about 2 to 20 carbon atoms such as 1, octene-1, and decene-1, and vinyl compounds such as vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, and styrene. And the like. Specific examples thereof include propylene-based resins such as propylene homopolymer, propylene-ethylene copolymer, and propylene-ethylene-butene-1 copolymer.

In the method for producing a polyester of the present invention, the α-olefin resin blended with the polyester is, for example, 4-methylpentene-1 homopolymers of α-olefin having about 2 to 8 carbon atoms, And other α-olefins having about 2 to 20 carbon atoms such as ethylene, propylene, butene-1, 3-methylbutene-1, pentene-1, hexene-1, octene-1, and decene-1. And the like. Specifically, for example, butene-1 homopolymer, 4-methylpentene-1
Homopolymer, butene-1-ethylene copolymer, butene-
Examples thereof include butene-1 type resins such as 1-propylene copolymers and copolymers of 4-methylpentene-1 and C _{2 to} C ₁₈ α-olefins.

In the method for producing a polyester of the present invention, examples of the polyamide resin blended with the polyester include butyrolactam, δ-valerolactam,
Polymers of lactams such as ε-caprolactam, enantolactam and ω-laurolactam, 6-aminocaproic acid,
Polymers of aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, undecamethylenediamine,
Aliphatic diamines such as 2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4-
Alicyclic diamines such as bis (aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane), diamine units such as aromatic diamines such as m- or p-xylylenediamine, and glutaric acid, adipic acid, suberic acid, Polycondensates with aliphatic dicarboxylic acids such as sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, dicarboxylic acid units such as aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and copolymers thereof Specifically, for example, nylon 4, nylon 6, nylon 7, nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610,
Nylon 611, Nylon 612, Nylon 6T, Nylon 6I, Nylon MXD6, Nylon 6 / MXD6,
Nylon MXD6 / MXDI, Nylon 6/66, Nylon 6/610, Nylon 6/12, Nylon 6/6
T, nylon 6I / 6T and the like. Further, these resins may be crystalline or amorphous.

Further, in the method for producing a polyester of the present invention, examples of the polyacetal resin blended with the polyester include polyacetal homopolymers and copolymers. As the polyacetal homopolymer, A
The density measured by STM-D792 is 1.4.
Polyacetal having a melt flow ratio (MFR) of 0 to 1.42 g / cm ³ , measured by ASTM D-1238 at 190 ° C. and a load of 2160 g of 0.5 to 50 g / 10 minutes is preferable.

Further, as the polyacetal copolymer,
The density measured by the method of ASTM-D792 is 1.
38 to 1.43 g / cm ³ , a polyacetal copolymer having a melt flow ratio (MFR) measured at 190 ° C. and a load of 2160 g of 0.4 to 50 g / 10 min by the measuring method of ASTMD-1238 was obtained. preferable. Examples of these copolymerization components include ethylene oxide and cyclic ethers.

Further, as a method of blending the thermoplastic resin such as the above-mentioned polyolefin resin with the polyester, a method of directly adding the thermoplastic resin to the polyester so that the content thereof is in the above range and melt-kneading Or, in addition to a conventional method such as a method of adding as a master-batch and melt-kneading, the above-mentioned thermoplastic resin is produced in the polyester production step, for example, during melt polycondensation, immediately after melt polycondensation, immediately after pre-crystallization. , During solid phase polymerization, immediately after solid phase polymerization, etc., or during the period from the end of the manufacturing stage to the molding stage, etc., as a powder or granules, or polyester chips It is also possible to use a method in which the above-mentioned thermoplastic resin member is mixed under such a flow condition as described above and then mixed and then melt-kneaded. Here, as a method of contacting the polyester chip-shaped body with the thermoplastic resin member under flowing conditions, the polyester chip is collided with the member in the space where the thermoplastic resin member is present. It is preferable to contact,
Specifically, for example, immediately after melt polycondensation of polyester,
Immediately after pre-crystallization, during manufacturing process such as solid-state polymerization,
Magnet part of pneumatic transportation pipe, gravity transportation pipe, silo, magnet catcher at the time of filling and discharging the transportation container at the transportation stage as a product of polyester chip, and at the time of loading the molding machine at the molding stage of polyester chip Or a part of the thermoplastic resin, or,
A method of transferring the polyester chips may be a method of lining the thermoplastic resin or a method of installing the thermoplastic resin member such as a rod-shaped or net-like body in the transfer path. The contact time of the polyester chip with the member is usually an extremely short time of about 0.01 second to several minutes, but a small amount of the thermoplastic resin can be mixed into the polyester.

Further, in the present invention, in order to produce a polyester having an appropriate crystallization rate and giving a small variation in the crystallization rate, before the polyester is contact-treated with a member made of the above-mentioned thermoplastic resin. In addition, by treating the polyester in a sieving process for removing fines and film-like substances and a removal process such as fines by an air stream, the fine content of polyester, the film-like substance content, or the fine content and film-like substance content. It is desirable to reduce the content of any one of the total content to 500 ppm or less.

On the other hand, when the member made of the thermoplastic resin and the polyester are contact-treated, it is preferable that the thermoplastic resin is present in a state of being adhered to the surface of the polyester chip. The thermoplastic resin member may be a polyester chip depending on the magnitude of the impact force when it collides with the member, the pressure force when contacting the member, or the impact resistance and peeling resistance of the thermoplastic resin member. There is also a state in which it is mixed with the above-mentioned contact-treated polyester chip in a state where it does not adhere to, that is, in a state independent of the polyester chip. The molded product obtained from the polyester in such a mixed state has a too high crystallization rate, or has a very large fluctuation in the rate.
In the case of a preformed body for a hollow molded body, only a hollow molded body having a large transparency and whitening and transparency unevenness, normal stretching is impossible, and large thickness unevenness and poor transparency can be obtained. Usually, the above contact-treated polyester is present as fine fine particles, but sometimes in the form of granules or agglomerates having an average particle diameter of about 0.5 to several mm, independent of the polyester chips. It may be mixed in. In such a case, the thermoplastic resin becomes a foreign substance in the obtained molded body, and as a result, the resulting molded body has unevenness in thickness, pores,
There are many defects such as whitening. Therefore, it is desirable to remove the fine particles, particles or lumps of the thermoplastic resin existing independently of the polyester chips before molding.

The method for separating and removing the fine particles, particles or lumps of the thermoplastic resin from the polyester which has been contact-treated with the member made of the thermoplastic resin includes the following methods. That is, after melt-polycondensed polyester or solid-phase polymerized polyester is contact-treated with a member made of the above-mentioned thermoplastic resin, it is treated by a vibration sieving step and a stream classification step by an air flow, or a washing step with ion-exchanged water. The thermoplastic resin in the form of fine granules, granules and lumps is removed by a method such as the method described above, or a method of performing a floating selection treatment. The method of separating and removing the fine particles, particles or lumps of the thermoplastic resin as described above is also effective as a method of removing the polyester fines or film-like materials described below.

In the production process of polyester, a silo or molding machine is passed through each step such as a melt polycondensation step to a solid phase polymerization step, or a melt polycondensation step or a solid phase polymerization step to a sieving step or an air stream classification step. The container is filled with a container such as a hopper or a shipping container, and the air near the processing equipment is generally taken into the process by a blower or the like to transport and dry the polyester between these processes. Conventionally, such air is either left untreated or treated by a purifier equipped with a low-performance filter unit such as type 3 specified in JIS B 9908 (1991). Was generally used in. However, when the air treated in such a process is used, there is a problem that only a molded product having poor transparency can be obtained.

Therefore, in the method for producing polyester of the present invention, from the step of transporting the polyester chips obtained in the melt polycondensation step to the next step, as the gas to be contacted with the polyester in the subsequent steps,
It is desirable to use a gas having a particle size of 0.3 to 5 μm that is introduced from outside the system of 1,000,000 (pieces / cubic foot) or less.

Particles having a particle size of less than 0.3 μm in a gas are not particularly specified, but the smaller amount is preferable in order to obtain a resin giving a transparent molded body.
The number of particles having a particle size of less than 0.3 μm is preferably 100.
It is 00000 (pieces / cubic feet) or less, more preferably 5,000,000 (pieces / cubic feet) or less, and further preferably 2000000 (pieces / cubic feet or less).

A method for controlling the number of particles having a particle size of 0.3 to 5 μm in the gas introduced from outside the system to 1,000,000 (particles / cubic foot) or less is illustrated below, but the present invention is not limited to this. Not something to do.

Particle size in gas introduced from outside the system 0.3 to 5
As a method for reducing the number of particles of μm to 1,000,000 (pieces / cubic foot) or less, a cleaning method for removing the particles at least at one or more places during the process until the gas introduced from the outside comes into contact with the polyester chips Install a chemical device.
In the case where the gas is air in the vicinity of the treatment equipment, JIS B 9 is used during the process in which the air introduced by the blower from the air inlet comes into contact with the polyester chips.
908 (1991), a gas purifying apparatus equipped with a type 1 or / and type 2 filter unit is installed, and the number of particles having a particle size of 0.3 to 5 μm in the air is set to 10
It is preferable that the number is 00000 (pieces / cubic foot) or less. In addition, JIS B 990 is installed in the air intake port described above.
It is possible to extend the life of the filter unit by installing the gas cleaning device equipped with the filter unit of the type 3 defined in 8 (1991) and using it together with the gas cleaning device equipped with the filter unit. Is.

JIS B 99 for removing particles in a gas
As a material of the ultra-high performance filter (hereinafter referred to as HEPA filter) unit of type 1 defined in 08 (1991), a filter paper made of glass fiber can be mentioned.

In addition, JIS B 9908 (1991)
Examples of the material of the high performance filter unit of the type 2 defined in 1. include a filter made of polypropylene fiber, a filter made of a laminated body of polytetrafluoroethylene film and PET fiber cloth, and the like. Generally, an electrostatic filter made of polypropylene fiber is used.

Also, JIS B 9908 (1991)
Examples of the material of the low-performance filter unit of the type 3 defined in 1. include non-woven fabric made of PET or polypropylene.

The polyester according to the present invention may contain other additives, if necessary, such as known ultraviolet absorbers, antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from the outside and internal additives during the reaction. You may mix | blend various additives, such as the deposited lubricant, mold release agent, nucleating agent, stabilizer, antistatic agent, and pigment.

The polyester obtained by the above-mentioned production method of the present invention is injection-molded and stretch-blow-molded into a stretched hollow-molded product, a direct blow-molded hollow-molded product, and an extrusion-molded sheet. The material is formed into a film or a film obtained by further stretching the material.

[0143]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method of the main characteristic value in this specification is demonstrated below.

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

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

(3) Acetaldehyde content of polyester (hereinafter referred to as “AA content”) Sample / distilled water = 1 g / 2 cc The upper part of a glass ampoule with nitrogen substitution was sealed, and the mixture was extracted at 160 ° C. for 2 hours. After treatment and cooling, acetaldehyde in the extract was measured by high sensitivity gas chromatography and the concentration was expressed in ppm.

(4) Content of cyclic trimer of polyester (hereinafter referred to as "CT amount") A sample is dissolved in a hexafluoroisopropanol / chloroform mixture solution, and chloroform is further added to dilute it. Methanol is added to this to precipitate a polymer, which is then filtered. The filtrate was evaporated to dryness, adjusted to a constant volume with dimethylformamide, and the cyclic trimer composed of ethylene terephthalate units was quantified by liquid chromatography.

(5) Increasing amount of cyclic trimer during melting of polyester (ΔCT amount) 3 g of dried polyester chips were placed in a glass test tube and immersed in an oil bath at 290 ° C. for 60 minutes under a nitrogen atmosphere to melt. Let The amount of cyclic trimer increase during melting is determined by the following formula. Increase of cyclic trimer at melting (wt%) = cyclic 3 after melting
Content of monomer (% by weight) -Content of cyclic trimer before melting (% by weight)

(6) Measurement of fine content and film-like material content About 0.5 kg of resin was used as a sieve (A) with a wire mesh having a nominal size of 5.6 mm according to JIS-Z8801 and a nominal size of 1.7.
A sieve (diameter 20 cm) (B) having a metal mesh of mm was placed on the sieve in which the two stages were combined, and sieved with a rocking type sieving tow machine SNF-7 manufactured by Terraoka at 1800 rpm for 1 minute. This operation was repeated, and a total of 20 kg of the resin was sieved. If, in addition to the film-like material, two or more chips fused to each other or a chip-like material cut into a size larger than the normal shape are captured on the sieve (A), The remaining film-like material from which the syrup was removed and the fines sieved off under the sieve (B) were separately washed with ion-exchanged water, filtered with a G1 glass filter manufactured by Iwaki Glass Co., Ltd., and collected. These are put together with the glass filter in a dryer at 100 ° C.
After drying for 2 hours, it was cooled and weighed. The same operation of washing with ion-exchanged water and drying was repeated again to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain the fine weight and the weight of the film-like material.
Fine content or film content is fine weight or film weight / total screened resin weight. The total content is calculated from these values.

(7) Measurement of fine peak temperature of fine particles Differential scanning calorimeter (DS) manufactured by Seiko Denshi Kogyo KK
C), measured using RDC-220. In (6),
Fines collected from 20 kg of polyester were dried under reduced pressure at 25 ° C for 3 days, and a sample of 4 m was used for each measurement.
DSC measurement at a temperature rising rate of 20 ° C./min using g,
The melting peak temperature on the highest side of the melting peak temperature is determined. 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.

(8) Crystallization temperature (Tc
1) Differential thermal analyzer (DS) manufactured by Seiko Electronics Co., Ltd.
C), measured with RDC-220. Using 10 mg of a sample from the center of a 2 mm-thick plate of the following (15) molded plate. The temperature is raised at a temperature rising rate of 20 ° C./minute, and the peak temperature of the crystallization peak observed during the heating is measured and used as the crystallization temperature during heating (Tc1).

(9) Number of spherulites during temperature rising crystallization of the molded body A test piece of 8 mm x 10 mm was cut out from a plate portion having a thickness of 3 mm from the stepped molded plate of (15) below and used as a measurement sample. . The molded plate has a molecular orientation derived from the flow at the time of molding, but the orientation state varies depending on the site of the molded plate. Therefore, by sandwiching the molding plate between two polarizing plates whose polarization planes are orthogonal to each other, and observing the intensity distribution of the light passing through the molding plate when irradiating visible light from the direction perpendicular to the polarizing plate surface, the alignment is performed. I confirmed the condition. A test piece was cut out from a site that did not include nonuniform molecular orientation (orientation degree, orientation fluctuation, etc.) within the above dimensions.
At that time, the direction of the optical anisotropy is confirmed in advance, and the relationship with the direction of the test piece to be cut out is as follows. The orientation of the optical anisotropy was determined by a method described in New Polymer Experiment 6 Polymer Structure (2) (Kyoritsu Shuppan Co., Ltd.) using a polarizing microscope and a sensitive color inspection plate. The test piece was cut out so that the direction of the axis of small refractive index (axis of high light velocity) and the long axis of the test piece were parallel to each other. The disordered orientation and the unevenness of the cut surface introduced when cutting out the test piece significantly affect the measurement result. Therefore, the unevenness of the cut surface and the part in which the orientation was disturbed were removed by using a cutter to obtain a flat surface. In addition, the density of the test piece and the degree of molecular orientation also affect the results. The density and birefringence values are 1.3345 to 1.3355 g / cm ³ , respectively.
And 1.30 × 10 ^{−4 to} 1.50 × 10 ⁻⁴ . The density was measured using a water-based density gradient tube, using a resin sampled from the vicinity of the test piece collection site as a sample. Birefringence is determined by a polarizing microscope (ECLIPSEE6 manufactured by Nikon Corporation).
00 POL) was used to measure by the Bereck compensator method. As the measured value, the value obtained at the center of the test piece was adopted. The test piece prepared as described above was
Thermo-mechanical analysis (TMA) manufactured by Science, type TMA 4
It heat-processed at 000S. 0.2g constant compression load, Ar
In the atmosphere, the temperature is raised from room temperature to 210 ° C at a rate of 27 ° C / min.
The temperature is lowered at a rate of ° C / min., And the number of spherulites is measured by the following method.

A Leica microtome RM2065 is used to prepare a 2 μm thick section from the end of the test piece. This section is observed using a Nikon polarization microscope ECLIPSE E600POL. For observation, halogen lamp light was used as a light source, and monochromaticization was not performed by an interference filter or the like. The optical system is adjusted to a so-called crossed nicols state in which the optical axes of the polarizer and the analyzer are orthogonal to each other, and a sensitive color inspection plate of 530 nm is inserted in the optical path. The image is a color CCD camera (HITACH) connected to a polarization microscope.
I HV-C205) and save it as a still image on a Macintosh computer via an image capture board.

When observing the section with the above optical system,
Many spherulites are observed. When a 530 nm sensitive color inspection plate is inserted into the optical path for observation, the spherulites show symmetry reflecting the orientation of the optical anisotropy inside them. Specifically, spherulites are observed as if they were divided into four with their centers being symmetrical. Then, different colors are exhibited in the parallel direction and the vertical direction with respect to the axis having a low refractive index of the sensitive color inspection plate (parallel to the insertion direction). This color is an interference color when the retardation generated by the inspection plate increases with the sample and an interference color corresponding to the case where it decreases, and the azimuth of the optical axis of the inserted inspection plate and the optical inside the spherulites. Determined by the relationship of anisotropic orientation.

105 μm × 79 on the sample using a CCD camera
Take a picture of the μm area and save it in a computer recording device (such as a hard disk or magneto-optical disk).
From this image, the number of spherulites is measured using the image processing software Ultimage / Pro (Image and Measurement Co., Ltd.) on a Macintosh computer according to the following procedure. As described above, spherulites have two kinds of colors. Threshold level is set so that only one of the colors remains, and binarization is performed. By this operation, only the portion having one color is the measurement target. In addition, Primary Morp
Erosion in the hology menu is Number of integrations = 1
Run with. By this operation, the portions which are originally belonging to different spherulites but are connected are separated. After executing this operation, execute the Particle menu and read the value of Detected particles. At this time,
Particles with an area of 4 pixels or less are not measured. Since two particles are measured per spherulite, the value obtained by dividing the value of Detected particles read earlier by 2 is taken as the number of spherulites.

(10) Average density of polyester chips,
Preform plug density and plug density deviation were measured at 30 ° C. with a density gradient tube of a calcium nitrate / water mixed solution. The density of the plug portion was calculated as an average value of 10 samples crystallized by the method (13), and the density deviation of the plug portion was calculated from the density values of these 10 samples.

(11) Haze (% of haze) and haze unevenness Samples were cut from the body of the following (15) (wall thickness 5 mm) and the body of the hollow molded body (16) (wall thickness about 0.45 mm). Measured with a haze meter manufactured by Nippon Denshoku Co., Ltd. Also,
The haze of the hollow molded article which was continuously molded 10 times was measured,
The haze spots were obtained by the following. Haze spot = maximum haze value / minimum haze value

(12) Foreign matter of hollow molded body Three hollow molded bodies of the following (16) were visually observed, averaged, and evaluated as follows. ◎: No foreign matter ○: Very small amount of foreign matter (3 or less foreign matter having a size of 0.5 mm or less per hollow molded article) △: 0.5 mm or more per hollow molded article 5 to 10 foreign matter x: There are a large number of foreign matter (0.
(10 or more foreign objects with a size of 5 mm or more)

(13) Density increase due to heating of preform mouthpiece The preform mouthpiece was heat treated for 60 seconds with a home-made infrared heater, and a sample was taken from the top surface to measure the density.

(14) Bottle thickness variation Samples (3 cm × 3 cm) at four locations were randomly cut from the center of the body of the hollow molded article of (16) to be described later, and the thickness was measured with a digital thickness meter (in the same sample). Was measured at 5 points each, and the average was taken as the sample thickness). Thickness unevenness was determined by the following. Thickness unevenness = maximum thickness / minimum thickness

(15) Molding of Stepped Molded Plate A dried polyester is manufactured by Meiki Seisakusho M-150C (D
M) Molded by an injection molding machine at a cylinder temperature of 290 ° C. using a stepped flat plate mold cooled to 10 ° C. The obtained stepped molded plate was 2, 3, 4, 5, 6, 7, 8,
It is equipped with 9,3,11 mm thick plates of about 3 cm x about 5 cm square in a stepwise manner, and the weight of one piece is about 146.
It is g. 2m thickness plate is 3m for Tc1 measurement
The m-thick plate is for measuring the number of spherulites at the time of temperature increase, and is 5 mm.
The thickness plate is used for haze (% haze) measurement.

(16) Molding of Hollow Molded Body Polyester was dried with a dryer using nitrogen, and the resin temperature was 2 with an M-150C (DM) injection molding machine manufactured by Meiki Seisakusho.
The preform was molded at 95 ° C. The mouthpiece of this preform was heated and crystallized by a homemade mouthpiece crystallization device, and then biaxially stretch blow molded using a LB-01 stretch blow molding machine manufactured by Co-Poplast Co., Ltd., and subsequently at about 155 ° C. It was heat-fixed in the mold set as above to obtain a 2000 cc hollow molded body.

(17) Leakage Evaluation of Contents from Hollow Molded Body The hollow molded body molded in (16) above was filled with hot water at 90 ° C., capped with a capping machine, the container was laid down, and the contents were left. I investigated the leak. In addition, the state of deformation of the spout after capping was also examined.

(18) Introduced water introduced into the chip forming step and sodium content, calcium content, magnesium content and silicon content introduced water in the introduced water of the water treatment step were collected, and 1G1 glass manufactured by Iwaki Glass Co., Ltd. Filter-
After filtering with, the filtrate was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation.

(19) Particle Size and Number of Particles in Introduced Water Introduced in Chiping Step and Introduced Water in Water Treatment Step Light-shielding particle measuring instrument HIAC / ROYCO. Manufactured by Pacific Scientific Company. Counter 4
The measurement was performed using a 100 type and a sampler 3000 type.

(20) Measurement of Number of Particles in Gas Contacting Polyester The gas sent by a blower or the like for forcibly sending the gas, which has passed through the gas cleaning device, is branched from the main gas stream before coming into contact with the polyester. It is introduced into a particle measuring instrument and measured.
The measurement is repeated 5 times, the average value is obtained, and the number per 1 cubic foot of gas is calculated. As the particle measuring instrument, a light scattering type particle measuring instrument KC-01B manufactured by Rion Co., Ltd. was used.

(21) Sodium content and potassium content of germanium dioxide 0.5 g of a sample was dissolved in 6N-hydrochloric acid in a quartz beaker and evaporated to dryness, and the residue was dissolved in hydrochloric acid. 1.2M
-Use a hydrochloric acid solution and measure by atomic absorption spectrometry.

Example 1 A slurry of high-purity terephthalic acid and ethyl glycol was continuously supplied to a first esterification reactor containing a reactant in advance, and the slurry was stirred to about 2
The reaction was carried out at 50 ° C. and 0.5 kg / cm ² G for an average residence time of 3 hours. This reaction product was sent to the second esterification reactor and reacted under stirring at about 260 ° C. and 0.05 kg / cm ² to a predetermined degree of reaction. Also, a crystalline solution of crystalline germanium dioxide having a sodium content of 0.7 ppm and a potassium content of 0.5 pm is dissolved in water by heating, and ethylene glycol is added to the solution to perform a heat treatment, and a catalyst solution and a phosphoric acid ethylene glycol solution are added. Were continuously fed separately to the second esterification reactor. The esterification reaction product was continuously fed to the first polycondensation reactor and stirred at about 265 ° C. for 25 hours.
1 hour at torr and then with stirring in the second polycondensation reactor,
Polycondensation was carried out at about 265 ° C. and 3 torr for 1 hour, and further under stirring in the final polycondensation reactor at about 275 ° C. and 0.5 to 1 torr for 1 hour. The intrinsic viscosity of the melt polycondensation prepolymer was 0.51 dl / g.

The melt polycondensation reaction product was obtained by treating industrial water (derived from river underflow water) with a filter-filtration device and an ion exchange device, and about 550 particles / 10 particles having a particle size of 1 to 25 μm / 10.
ml, sodium content 0.02 ppm, magnesium content 0.01 ppm, calcium content 0.0
After cooling the chips with cooling water containing 1 ppm and silicon content of 0.07 ppm so that the chip temperature is about 40 ° C. or less, the chips are transported to a storage tank, and then finely divided by a vibrating sieving process and an air flow classifying process. Fine content of about 20p by removing the film and film
It was pm or less.

Then, it was sent to a crystallizer by a plug transport system, continuously crystallized under nitrogen gas flow at about 155 ° C. for 3 hours, then charged into a tower type solid phase polymerizer, and flowed under nitrogen gas at about 209 ° C. Solid-state polymerization was continuously carried out to obtain solid-state polymerized polyester. After the solid phase polymerization, fines and film-like substances were removed by continuous treatment in a sieving step and a fines removing step, and stored in a storage tank under a nitrogen stream.

The PET thus obtained had an intrinsic viscosity of 0.74 deciliter / gram, a DEG content of 2.8 mol%, a cyclic trimer content of 0.30% by weight, and an increased cyclic trimer content of 0.10%. 41% by weight, average density 1.4021 g / cm ³ ,
AA content is 2.7ppm, Fine content is about 45pp
m, and the peak temperature on the highest side of the melting peak temperature was 245 ° C. Ge measured by atomic absorption spectrometry
The residual amount was 51 ppm, and the residual P amount was 33 ppm.

In addition, in the solid-state polymerization reaction of Example 1 to Comparative Example 2, in each Example and Comparative Example,
A hole-cleaned continuous solid-state polymerization apparatus was used, and solid-state polymerization PET 3 months after the start of continuous production was used for molding evaluation and bottle molding evaluation. In addition, the transportation of the melt polycondensation PET chips in the manufacturing process was all performed by the plug type transportation system. In addition, as air for sending the melt polycondensation PET chips to the solid-state polymerization step, and air for contacting the solid-state polymerization PET chips with the chips before filling the storage container, JISB 990 is used.
8 (1991) type 3 PET non-woven filter unit equipped with an air cleaner and JIS B 9908
HEP with (1991) type 1 particle collection rate of 99% or more
Air filtered by an air cleaner equipped with the A filter unit (the number of particles having a particle size of 0.3 to 5 μm is about 500 / cubic foot) was used. Examples 2-5 and Comparative Examples 1, 2
However, similarly filtered air was used. This PET
Was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1.

The haze of the molded plate was 3.2%, the Tc of the molded plate was
1 is 170 ° C., and the number of spherulites of the formed plate is 4.0 × 10 ⁹ pieces / m ²
Met. The density of the bottle cap is 1.376 g / c
m ³ and the density deviation were 0.003 g / cm ^3, which were no problem values, the haze of the body of the bottle was 0.8%, and the haze unevenness was 1.
1, the thickness unevenness was 1.03, which was good. The foreign matter of the hollow molded article was “⊚ (no foreign matter exists)”, and there was no problem. In addition, in the leak test of the contents, there was no problem and the mouth plug was not deformed. AA content of bottle is 20.3ppm
And was a value without problems.

Example 2 Same as Example 1 except that the crystalline germanium dioxide used in Example 1 and the ethylene glycol solution of aluminum acetylacetonate are separately fed continuously to the second esterification reactor. And a polycondensation polymer with an intrinsic viscosity of 0.52 dl / g
Got Then, solid phase polymerization was carried out under the same conditions as in Example 1 using the same apparatus. The PET obtained had an intrinsic viscosity of 0.74.
Deciliter / gram, the DEG content is 2.7 mol%,
Cyclic trimer content is 0.31% by weight, cyclic trimer increase is 0.40% by weight, average density is 1.4021 g / c
m ³ , AA content is 2.9 ppm, fine content is about 4
0 ppm, and the peak on the highest side of the melting peak temperature
The temperature was 246 ° C. Ge residual amount measured by atomic absorption spectrometry is 35 ppm, Al content is 20 ppm,
The residual P amount was 35 ppm. In addition, a plug-type transportation method was used for all transportation of the melt polycondensation PET chips in the manufacturing process.

This PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The haze of the molded plate is 4.2%, the Tc1 of the molded plate is 166 ° C.,
The spherulite number of the formed plate was 6.3 × 10 ⁹ pieces / m ² . Bottle mouth density of the plug portion is 1.379g / cm ^3, the density deviation of no value problem and 0.001 g / cm ^3, the body portion haze of bottle 1.1%, haze plaques 1.1, thickness The spots were as good as 1.01. Foreign matter of the hollow molded product is
(There is no foreign substance) ”, and there was no problem. Also,
In the leak test of the contents, there was no problem and the mouth plug was not deformed. The AA content of the bottle was 21.2 ppm, which was a value with no problem.

Example 3 Example 1 was repeated except that the crystalline germanium dioxide and the tetraisopropyl titanate ethylene glycol solution used in Example 1 were separately and continuously fed to the second esterification reactor. Similarly, a melt polycondensation polymer having an intrinsic viscosity of 0.52 dl / g was obtained. Then, solid phase polymerization was carried out under the same conditions as in Example 1 using the same apparatus. The obtained PET had an intrinsic viscosity of 0.74 deciliter / gram, a DEG content of 2.7 mol%, a cyclic trimer content of 0.31% by weight, and a cyclic trimer increment of 0.40.
% By weight, average density 1.4021 g / cm ³ , AA content 3.3 ppm, fine content about 45 ppm, and peak temperature on the highest melting peak side is 245.
It was ℃. The amount of Ge remaining measured by atomic absorption spectrometry is 30 ppm, the content of Ti is 2 ppm, and the amount of P remaining is 3 ppm.
It was 0 ppm. In addition, a plug-type transportation method was used for all transportation of the melt polycondensation PET chips in the manufacturing process.

This PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The haze of the molded plate is 3.3%, the Tc1 of the molded plate is 167 ° C.,
The spherulite number of the formed plate was 6.0 × 10 ⁹ pieces / m ² . Bottle mouth density of the plug portion is 1.378g / cm ^3, the density deviation of no value problem and 0.001 g / cm ^3, barrel haze of 1.0% of the bottle, haze plaques 1.1, thickness The spots were as good as 1.01. Foreign matter of the hollow molded product is
(There is no foreign substance) ”, and there was no problem. Also,
In the leak test of the contents, there was no problem and the mouth plug was not deformed. The AA content of the bottle was 22.2 ppm, which was a value with no problem.

Example 4 A slurry of high-purity terephthalic acid and ethyl glycol was continuously fed to a first esterification reactor containing a reactant in advance and magnesium acetate tetrahydrate was added. While continuously feeding the ethylene glycol solution, while stirring, at about 250 ° C., 0.5 kg / cm ²
The reaction was carried out in G with an average residence time of 3 hours. The reaction product was sent to the second esterification reactor and stirred at about 260 ° C.
The reaction was carried out at 0.05 kg / cm ² to a predetermined degree of reactivity. A solution of tetraisopropyl titanate in ethylene glycol, the crystalline germanium dioxide used in Example 1 was dissolved in water by heating, and ethylene glycol was added to the solution and the solution was heat-treated individually in a second esterification reactor. Was continuously fed to. Then, phosphoric acid ethylene glycol
Solution from the second esterification reactor to the first polycondensation reactor was continuously fed into the transportation pipe. The esterification reaction product is continuously fed to the first polycondensation reactor and stirred,
About 265 ° C., 0.5 torr, 25 torr for 1 hour, then the second polycondensation reactor with stirring, about 265 ° C., 3 torr for 1 hour, and the final polycondensation reactor with stirring for about 275 ° C., 0.5-
Polycondensation at 1 torr for 1 hour, IV 0.51 dl /
g of melt-polycondensation polymer was obtained, and chips were formed using water treated with the same ion exchange apparatus under the same conditions as in Example 1.
Then, solid phase polymerization was carried out under the same conditions as in Example 1 using the same apparatus.

The PET thus obtained had an intrinsic viscosity of 0.74 deciliters / gram, a DEG content of 2.4 mol%, a cyclic trimer content of 0.32% by weight, and a cyclic trimer increment of 0. 42% by weight, average density 1.4021 g / cm ³ ,
AA content is 3.5ppm, fine content is about 30pp
m, and the peak temperature on the highest side of the melting peak temperature was 245 ° C. Ge measured by atomic absorption spectrometry
The residual amount was 27 ppm, the Ti residual amount was 1 ppm, the Mg residual amount was 10 ppm, and the P residual amount was 30 ppm.
In addition, a plug-type transportation method was used for all transportation of the melt polycondensation PET chips in the manufacturing process.

This PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The haze of the molded plate is 4.5%, the Tc1 of the molded plate is 165 ° C.,
The spherulite number of the formed plate was 7.0 × 10 ⁹ pieces / m ² . Bottle mouth density of the plug portion is 1.381g / cm ^3, the density deviation of no value problem and 0.001 g / cm ^3, barrel haze 1.2% of the bottle, haze plaques 1.1, thickness The spots were as good as 1.01. Foreign matter of the hollow molded product is
(There is no foreign substance) ”, and there was no problem. Also,
In the leak test of the contents, there was no problem and the mouth plug was not deformed. The AA content of the bottle was 21.7 ppm, which was a value with no problem.

(Example 5) The PET obtained in Example 3 was treated with water as follows. The raw material chip supply port (1) at the upper part of the treatment tank, and the opening located at the upper limit level of the treated water in the treatment tank.
Overflow outlet (2), outlet for the mixture of polyester chips and treated water at the bottom of the treatment tank (3), overflow
A fine filtration removal device in which the treated water discharged from the discharge port and the treated water discharged from the discharge port at the lower part of the treatment tank through the drainer (4) for polyester chips are continuous filters of paper ( 5) and a pipe (6) sent to the water treatment tank again via the adsorption tower (8), a device for removing particles in water which is a GAF filter-bag PE-1P2S (polyester felt, filtration accuracy 1 μm) manufactured by ISP 50m ^{3 of} internal volume equipped with a water inlet (7) obtained by introducing new ion-exchanged water from outside the system into the inlet (9) in the middle of this pipe (6) via The PET chip was continuously treated with water using the tower type treatment tank shown in FIG.

The above solid-state polymerized PET chips were continuously charged from the upper supply port (1) of the treatment tank controlled at the treatment water temperature of 95 ° C., and the discharge port at the bottom of the water treatment tank after a water treatment time of 3 hours. The water treatment was performed while continuously extracting the PET chip together with the treated water from (3). The content of particles having a particle size of 1 to 25 μm in the introduced water collected in front of the ion-exchanged water introduction port (9) of the above treatment device was about 500 particles / 10 ml, the sodium content was 0.02 ppm, and the magnesium content was 0. 02ppm, calcium content 0.02pp
m, the silicon content was 0.08 ppm, and the number of particles of the recycled water after treatment in the filtration device (5) and the adsorption tower (8) was 12,000 particles / 10 ml.

The PET after the water treatment was continuously dried by a dryer using dehumidified heated air, and then fines were removed by a vibrating screen step and an air stream classification step. PET obtained
Has an intrinsic viscosity of 0.74 deciliters / gram, a DEG content of 2.7 mol%, a cyclic trimer content of 0.31 wt%, a cyclic trimer increase of 0.10 wt%, and an AA content. The content is 2.8 ppm, the content of fines is about 30 ppm, and the peak temperature on the highest side of the melting peak temperature is 24 ppm.
It was 5 ° C. The transportation of the melt-polymerized prepolymer chips in the manufacturing process was carried out by the plug-type transportation system.

This PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The haze of the molded plate is 4.1%, the Tc1 of the molded plate is 163 ° C.,
The spherulite number of the formed plate was 7.5 × 10 ⁹ pieces / m ² . Bottle mouth density of the plug portion is 1.381g / cm ^3, the density deviation of no value problem and 0.001 g / cm ^3, barrel haze 1.3% of the bottle, haze plaques 1.1, thickness The spots were as good as 1.01. Foreign matter of the hollow molded product is
(There is no foreign substance) ”, and there was no problem. Also,
In the leak test of the contents, there was no problem and the mouth plug was not deformed. The AA content of the bottle was 16.4 ppm, which was a problem-free value.

Comparative Example 1 A solid-state polymerized PET was obtained in the same manner as in Example 1 except that crystalline germanium dioxide having a sodium content of about 350 ppm was used as the polycondensation catalyst. The PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The transparency of the obtained bottle was poor, and the deformation of the spout and leakage of the contents were examined, and leakage of the contents was found.

(Comparative Example 2) A crystalline germanium dioxide having a sodium content of about 350 ppm was used as a polycondensation catalyst, and a filter-filtration device and an ion exchange device were used as cooling water for chip formation of the melt polycondensed polyester. Industrial water without use (particles with a particle size of 1 to 25 μm are about 1
20,000 pieces / 10ml, sodium content 5.1ppm,
Solid-state polymerized PET was obtained in the same manner as in Example 1 except that magnesium content of 3.3 ppm, calcium content of 4.2 ppm and silicon content of 7.7 ppm) were used as they were as cooling water for chip formation. It was The PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The transparency of the obtained bottle was poor, and the deformation of the stopper and the leakage of the contents were examined.
Leakage of contents was recognized. In addition, the amount of foreign substances in the bottle wall was so large that the bottle had no commercial value. The foreign matter was taken out and metals such as calcium and silicon were detected by X-ray microanalyzer analysis.

[0187]

[Table 1]

[0188]

EFFECTS OF THE INVENTION According to the method for producing a polyester of the present invention, a molded product having excellent transparency and little fluctuation in crystallization rate can be obtained. Further, the molded product contains almost no foreign matter, and the polyester and filter-filtration pressure increase. It is possible to advantageously obtain a polyester having a low content.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used for water treatment of polyester in Examples.

[Explanation of symbols] 1 raw material chip supply port 2 overflow discharge port 3 discharge port for polyester chips and treated water 4 drainer 5 fines removal device 6 piping 7 recycled water or / and ion exchanged water inlet 8 Adsorption tower 9 Ion exchange water inlet

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shumu Kimura             26-21 Akao-cho, Otsu City, Shiga Prefecture (72) Inventor Yoshitaka Eto             20 No. 248 Takashiro, Shiga Town, Shiga District, Shiga Prefecture F term (reference) 4J029 AD01 AD06 AD10 AE01 AE03                       BA02 BA03 BD06A CB06A                       CB10A CC06A CF15 JA061                       JA091 JA121 JB131 JB151                       JB171 JC351 JC371 JE043                       JE133 JE203 JF131 JF151                       JF181 JF221 JF231 JF321                       JF331 JF351 JF361 JF371                       JF381 JF471 JF511 JF541                       JF561 JF571

Claims (8)

[Claims] 1. A dicarboxylic acid having an aromatic dicarboxylic acid as a main component or an ester-forming derivative thereof, and a glycol or an ester thereof, using crystalline germanium dioxide having an alkali metal content of 100 ppm or less as a polycondensation catalyst. A method for producing a polyester, which comprises obtaining a low polycondensate from a forming derivative and then polycondensing this. 2. Mg, Al, Si, Ti, Mn, Fe,
The method for producing a polyester according to claim 1, wherein a compound containing at least one element selected from the group consisting of Co, Zn, Ga, Sr, Zr, Sn, Sb, W and Pb is allowed to coexist. 3. The residual amount of the compound containing at least one element according to claim 2 is 0.0001 to 0.3 mol% as an element with respect to the acid component of the polyester. The method for producing the polyester according to claim 2. 4. The polyester has a sodium content (N), a magnesium content (M), a silicon content (S), and a calcium content (C) as defined in (1) below.
The method for producing a polyester according to any one of claims 1 to 3, wherein the polyester is made into chips while being cooled with cooling water satisfying at least one of (4) to (4). N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4) 5. The content of any one of the fine content and the film-like content of polyester or the total content of the fine content and the film-like content is 5000 p.
It is below pm, The manufacturing method of the polyester in any one of Claims 1-4 characterized by the above-mentioned. 6. The polyester has an intrinsic viscosity of 0.55.
1.5 deciliter / gram, acetaldehyde content of 10 ppm or less, cyclic trimer content of 0.5% by weight or less, haze of a molded plate obtained by injection molding is 15% or less, molded plate measured by DSC Crystallization temperature (T
c1) is 150 to 175 ° C., and the number of spherulites generated when the shaped plate is heated and crystallized is in the range of 2 × 10 ⁹ to 15 × 10 ⁹ pieces / m ² , and ethylene terephthalate is the main repeating unit. The method for producing polyester according to claim 1, wherein the polyester is 7. The method for producing a polyester according to claim 1, wherein the polyester is subjected to a contact treatment with water. 8. The polyester according to claim 1, wherein the polyester is blended with at least one resin selected from the group consisting of a polyolefin resin, a polyamide resin and a polyacetal resin. Manufacturing method.