JP2002338676A - Process for producing polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a polyester which is excellent in long-term continuous moldability and can give a molded article, particularly a heat-resistant hollow molded article, excellent in transparency and high- temperature dimensional stability and undergoing little change in the rate of crystallization. SOLUTION: The process for producing a polyester involves a step (a) of producing an oligomer by subjecting an aromatic dicarboxylic acid or its functional derivative and a glycol or its functional derivative to esterification or transesterification, a step (b) of subjecting the oligomer obtained in the step (a) to melt polycondensation, a step (c) of treatment with water by bringing the polyester obtained in the step (b) into contact with water, a step (d) of contact treatment by bringing the polyester obtained in the step (c) into contact with a member comprising a crystalline thermoplastic resin, and a step (e) of removing fines and/or materials in a film form from the polyester obtained in the step (d).

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 polyester which is suitably used as a material for molded articles such as hollow molded articles such as bottles for beverages, films and sheets. The present invention relates to a method for producing a hollow molded article having excellent heat resistance and dimensional stability under heat and a polyester which gives a sheet-like material having excellent transparency, slipperiness and dimensional stability after molding.

[0002]

2. Description of the Related Art Polyesters whose main repeating unit is ethylene terephthalate (hereinafter sometimes abbreviated as PET) have excellent transparency, mechanical strength and heat resistance.
Depending on the properties such as gas barrier properties, carbonated beverages, juices,
It is used as a material for containers such as mineral water, and its use has been remarkable. In these applications, polyester bottles are hot-filled with beverages that have been sterilized at high temperatures, or beverages are sterilized at high temperatures after filling, but ordinary polyester bottles shrink during such hot-filling processes. However, deformation occurs and becomes a problem. As a method for improving the heat resistance of the polyester bottle, a method has been proposed in which the crystallinity is increased by heat-treating the bottle cap portion, or the stretched bottle is heat-fixed. In particular, if the plug portion is insufficiently crystallized or has a large variation in crystallinity, the sealing performance with the cap is deteriorated, and the contents may leak.

[0003] In the case of beverages that require hot filling, such as fruit juice beverages, Wurong tea and mineral water, the plug portion of the preform or molded bottle is heat treated to crystallize. (Methods described in JP-A-55-79237, JP-A-58-110221, etc.) are generally used. Such a method, that is, a method of improving the heat resistance by heat treatment of the plug portion and the shoulder portion, the time and temperature for the crystallization treatment greatly affect the productivity, and the crystal can be processed at a low temperature and in a short time. It is preferable that the PET is a PET having a high conversion rate. On the other hand, the body is required to be transparent even when subjected to a heat treatment at the time of molding so as not to deteriorate the color tone of the contents of the bottle, and the plug and the body need to have contradictory characteristics.

In order to improve the heat resistance of the body of the bottle, a method of performing heat treatment at a high temperature of a drawing blow mold as disclosed in Japanese Patent Publication No. 59-6216, for example, is adopted. However, when a large number of bottles are continuously formed using the same mold by such a method, the bottle obtained with a long operation is whitened, the transparency is reduced, and only a bottle having no commercial value can be obtained. . It was found that this was due to the attachment of the PET-derived material to the mold surface, resulting in mold stains, and the mold stains being transferred to the bottle surface. In particular, in recent years, the molding speed has been increased along with the miniaturization of bottles, and from the viewpoint of productivity, the shortening of the heating time for crystallization of the plug and the contamination of the mold have become more serious problems. .

Further, when PET is extruded into a sheet-like material, and a molded product obtained by vacuum-forming the same is filled with food and covered with a lid made of the same material and allowed to stand, shrinkage occurs and the openability of the lid is reduced. If the molded body is left unattended for a long period of time, shrinkage may occur and the lid may not be formed.

[0006]

Various proposals have been made to solve such a problem. For example, a method of adding an inorganic nucleating agent such as kaolin or talc to polyethylene terephthalate (JP-A-56-2342, JP-A-56-21832), or an organic nucleating agent such as a montanic acid wax salt. Although there is a method of adding (JP-A-57-125246 and JP-A-57-207639), these methods have a problem in practical use due to generation of foreign matters and cloudiness. Also, a method in which a treated polyester obtained by pulverizing a polyester molded product obtained by melt-molding the polyester is added to the raw material polyester (JP-A-5-105807).
However, this method requires an extra step of melt-molding and pulverization, and furthermore, there is a risk that impurities other than polyester may be mixed in such a post-process. is not. In addition, a method of inserting a heat-resistant resin piece into a plug (Japanese Patent Laid-Open No. 61-259)
946 and JP-A-2-26938), but the productivity of bottles is poor and there is a problem in recyclability.

Further, a method of modifying the crystallization rate of PET by bringing a PET chip into contact with a polyethylene member under flowing conditions (Japanese Patent Application Laid-Open No. 9-71639), or a polypropylene-based resin or polyamide-based resin under the same conditions. A method of modifying the crystallization rate of PET by contact with a resin member has been proposed (Japanese Patent Application Laid-Open No. H11-209492), but a stable crystallization rate and transparency can be obtained by such a method. Turned out to be very difficult.

The present invention solves the above-mentioned problems of the conventional method and can efficiently produce a molded article having excellent transparency and heat-resistant dimensional stability, especially a heat-resistant hollow molded article. It is an object of the present invention to provide a method for producing a polyester which is excellent in long-time continuous moldability without causing soiling of the polyester.

[0009]

In order to achieve the above object, a method for producing a polyester according to the present invention comprises esterifying or transesterifying an aromatic dicarboxylic acid or a functional derivative thereof with glycol or a functional derivative thereof. A low polymer production step (a), a melt polycondensation step of melt polycondensing the low polymer obtained in the low polymer production step (b), and contacting the polyester obtained in the melt polycondensation step with water. A water treatment step (c) to be treated, a contact treatment step (d) of contact-treating the polyester obtained in the water treatment step with a member made of a crystalline thermoplastic resin, and fine and fine polyesters obtained in the contact treatment step. And / or a fine or the like removing step (e) for removing a film-like material.

In this case, fine steps may be included in the intermediate step between the melt polycondensation step (b) and the water treatment step (c) and / or the intermediate step between the water treatment step (c) and the contact treatment step (d). And / or a step (g) of removing fine or the like for removing a film-like material can be added.

[0011] The method for producing a polyester of the present invention comprises:
Aromatic dicarboxylic acid or its functional derivative and glyco-
(A) a low-polymer production step of esterifying or transesterifying a low polymer or a functional derivative thereof, a melt polycondensation step (b) of melt-polycondensing the low polymer obtained in the low polymer production step, A solid phase polymerization step (f) for solid-phase polymerization of the polyester obtained in the melt polycondensation step, a water treatment step (c) of contacting the polyester obtained in the solid phase polymerization step with water, A contact treatment step (d) of contacting the obtained polyester with a member made of a crystalline thermoplastic resin, and a fine removal step (e) of removing fine and / or film-like substances from the polyester obtained in the contact treatment step. ).

In this case, an intermediate step between the melt polycondensation step (b) and the solid phase polymerization step (f), an intermediate step between the solid state polymerization step (f) and the water treatment step (c), or the water treatment step A step (g) for removing fines and / or a film-like substance may be added to at least one of the intermediate steps of (c) and the contact treatment step (d).

In this case, the content of any one of the fine content, the film content, or the total content of the fine content and the film content of the polyester treated in the fine etc. removing step (e) is included. If the quantity is 300
ppm or less.

Here, "fine" refers to JIS-Z8801.
Means fine polyester powder that has passed through a sieve with a 1.7 mm nominal size wire mesh, and film-like material remained on a 5.6 mm nominal size wire mesh sieve according to JIS-Z8801. Of the polyester, a film-like material from which two or more chips have been fused or a chip-like material that has been cut larger than a normal shape is removed, and the content of these is measured by the following measurement method. .

In this case, in the water treatment step (c),
Either the fine content of the polyester supplied to the contact treatment step (d) or the solid phase polymerization step (f), the content of the film, or the total content of the fine content and the content of the film. The content can be up to 300 ppm.

In this case, the highest peak temperature of the melting peak temperature of the fine and / or film-like substance contained in the polyester treated in the fine etc. removing step (e) is 265 ° C. It can be:

Here, as described below, the melting point of the fine or film-like material is measured using a differential scanning calorimeter (DSC), and the melting peak temperature of the 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 and the melting peak are determined. If there are multiple peaks, these multiple melting peaks
The melting peak temperature on the highest side of the peak is defined as the peak on the highest side of the melting peak temperature of the fine or film-like material.
The temperature is referred to as “the melting point of fine or the like” in Examples and the like.

In this case, the water treatment step (c),
Fine and / or fine particles contained in the polyester supplied to the contact treatment step (d) or the solid phase polymerization step (f).
Alternatively, the highest peak temperature of the melting peak temperature of the film may be 265 ° C or lower.

In this case, the crystalline thermoplastic resin can be at least one resin selected from the group consisting of a polyolefin resin, a polyamide resin, a polyacetal resin, and a polybutylene terephthalate resin.

In this case, the polyester is
The polyester having an intrinsic viscosity of 0.55 to 1.30 deciliters / gram in which the main repeating unit is composed of ethylene terephthalate can be used.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The process for producing a polyester according to the present invention comprises the steps of: (a) producing a low polymer in which an aromatic dicarboxylic acid or a functional derivative thereof is esterified or transesterified with a glycol or a functional derivative thereof; A melt polycondensation step (b) of melt-polycondensing the low polymer obtained in the above, a water treatment step (c) of subjecting the polyester obtained in the melt polycondensation step to contact treatment with water, and a water treatment step. Contacting the polyester obtained with a member made of a crystalline thermoplastic resin in a contact treatment step (d); removing fine and / or film-like substances from the polyester obtained in the contact treatment step (e); including.

The method for producing the polyester of the present invention comprises:
Aromatic dicarboxylic acid or its functional derivative and glyco-
(A) a low-polymer production step of esterifying or transesterifying a low polymer or a functional derivative thereof, a melt polycondensation step (b) of melt-polycondensing the low polymer obtained in the low polymer production step, A solid phase polymerization step (f) for solid-phase polymerization of the polyester obtained in the melt polycondensation step, a water treatment step (c) of contacting the polyester obtained in the solid phase polymerization step with water, A contact treatment step (d) of contacting the obtained polyester with a member made of a crystalline thermoplastic resin, and a fine removal step (e) of removing fine and / or film-like substances from the polyester obtained in the contact treatment step. ).

The polyester according to the present invention is preferably a crystalline polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, and more preferably, the aromatic dicarboxylic acid unit has 85 mol% of the acid component.
A polyester containing the above component, and particularly preferably a polyester containing an aromatic dicarboxylic acid unit in an amount of 95 mol% or more of the acid component.

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

The glycol component constituting the polyester according to the present invention includes alicyclic glycols such as ethylene glycol, trimethylene glycol, tetramethylene glycol and cyclohexanedimethanol. Is mentioned.

The acid component used by copolymerization in the polyester includes terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyl-4,4 '.
-Aromatic dicarboxylic acids such as dicarboxylic acid, diphenoxyethane dicarboxylic 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 derivatives thereof, and functional derivatives thereof, and 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 includes fatty acids such as ethylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol and neopentyl glycol. Alicyclic glycols such as aromatic glycol, cyclohexanedimethanol, aromatic glycols such as bisphenol A, alkylene oxide adducts of bisphenol A, polyethylene glycol, polybutylene glycol; And polyalkylene glycols such as

Further, polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, glycerin, pentaerythritol, and trimethylolpropane can be used as long as the polyester is substantially linear. It may be copolymerized, or a monofunctional compound such as benzoic acid or naphthoic acid may be copolymerized.

One preferred example of the polyester according to the present invention is a polyester whose main repeating unit is composed of ethylene terephthalate, and more preferably a linear polyester containing at least 85 mol% of ethylene terephthalate unit. Particularly preferred is a linear polyester containing 95 mol% or more of ethylene terephthalate units, that is, polyethylene terephthalate (hereinafter abbreviated as PET).

Another preferable example of the polyester according to the present invention is that the main repeating unit is ethylene-2,6-
It is a polyester composed of naphthalate, and more preferably 8 to 8 ethylene-2,6-naphthalate units.
A linear polyester containing 5 mol% or more, particularly preferred is a linear polyester containing 95 mol% or more of ethylene-2,6-naphthalate units, that is, polyethylene naphthalate.

Other preferable examples of the polyester according to the present invention include a linear polyester containing propylene terephthalate unit in an amount of 85 mol% or more, and a 1,4-cyclohexane dimethylene terephthalate unit in an amount of 85 mol% or more. Containing linear polyester or butylene terephthalate
Is a linear polyester containing 85 mol% or more of a pentamer unit.

The above polyester can be produced by a conventionally known production method. That is, in the case of PET, terephthalic acid is directly reacted with ethylene glycol and, if necessary, other copolymerization components to distill water and esterify, followed by polycondensation under reduced pressure. Law,
Alternatively, it is produced by a transesterification method in which dimethyl terephthalate is reacted with ethylene glycol and, if necessary, other copolymerization components to remove methyl alcohol and transesterify, followed by polycondensation under reduced pressure. . If necessary, solid-state polymerization may be performed in order to increase the intrinsic viscosity and reduce the acetaldehyde content and the like. In order to promote crystallization before solid-phase polymerization, the melt-polymerized polyester may be heated and then crystallized after moisture absorption, or steam may be directly blown onto the polyester chip for heat crystallization.

The melt polycondensation reaction may be carried out in a batch reactor or in a continuous reactor.
In any of these methods, the melt polycondensation reaction may be performed in one step or may be performed in multiple steps. The solid-state polymerization reaction can be performed in a batch-type apparatus or a continuous-type apparatus as in the melt polycondensation reaction. The melt polycondensation and the solid phase polymerization may be performed continuously or may be performed separately.

Hereinafter, an example of a preferable production method in a continuous system will be described using polyethylene terephthalate as an example. First, a case where a low polymer is produced by an esterification reaction will be described. A slurry containing 1.02 to 1.5 moles, preferably 1.03 to 1.4 moles of ethylene glycol per 1 mole of terephthalic acid or an ester derivative thereof was prepared, and this was subjected to an esterification reaction. Feed continuously to the process.

In the esterification reaction, water or alcohol produced by the reaction is rectified under a condition in which ethylene glycol is refluxed using a multistage apparatus in which at least two esterification reactors are connected in series. It is carried out while removing the system outside the column. The temperature of the first stage esterification reaction is 240 ~
270 ° C, preferably 245-265 ° C, pressure 0.2
３3 kg / cm ² G, preferably 0.5-2 kg / cm ²
G. The temperature of the final esterification reaction is usually 25.
The temperature is 0 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.
It is 3 kg / cm ² G. When the reaction is carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are the above-mentioned first conditions.
This is a condition between the reaction condition of the stage and the reaction condition of the final stage. The increase in the conversion 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 polymer 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 may be carried out in the presence of a polycondensation catalyst.

Also, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, tetraethylammonium hydroxide,
When a small amount of a quaternary ammonium hydroxide such as n-butylammonium and trimethylbenzylammonium hydroxide and a basic compound such as lithium carbonate, sodium carbonate, potassium carbonate and sodium acetate are added, the reaction of polyethylene terephthalate is reduced. It is preferable because the ratio of the dioxyethylene terephthalate component unit in the chain can be kept at a relatively low level (5 mol% or less based on all diol components).

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. Is prepared and continuously supplied to the transesterification step.

In the transesterification reaction, methanol produced by the reaction is passed through a rectification column under conditions where ethylene glycol is distilled back using a device in which one or two transesterification reactors are connected in series. Perform while removing outside the system. The temperature of the first-stage transesterification reaction is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the final transesterification reaction is usually 230 to 270 ° C., preferably 24 to 270 ° C.
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. By these transesterification reactions, the molecular weight is about 200 to 500.
A low polymer is obtained. Here, the low polymer production step (a) refers to a step of obtaining a low polymer by the above-mentioned esterification reaction or transesterification reaction.

Next, the obtained low polymer is supplied to a multi-stage liquid phase condensation polymerization step. The polycondensation reaction conditions are such that the reaction temperature of the first stage polycondensation is from 250 to 290 ° C, preferably from 2 to
60 to 280 ° C., the pressure is 500 to 20 Torr,
Preferably, the temperature is 200 to 30 Torr, and the temperature of the final polycondensation reaction is 265 to 300 ° C., preferably 275 to 2
The temperature is 95 ° C., and the pressure is 10 to 0.1 Torr, preferably 5 to 0.5 Torr. When the reaction is carried out in three or more stages, the reaction conditions for the polycondensation reaction in the intermediate stage are the first
This is a condition between the reaction condition of the stage and the reaction condition of the final stage. It is preferred that the degree of increase in the intrinsic viscosity reached in each of these polycondensation reaction steps be distributed smoothly.

The polycondensation reaction is performed using a polycondensation catalyst.
As the polycondensation catalyst, a compound of Ge, Sb, Ti, or Al is used.
It is also convenient to use a mixed catalyst of a compound and an Al compound, a Sb compound and a Ti compound, or a Sb compound and a Ge compound. These compounds are added to the reaction system as a powder, an aqueous solution, an ethylene glycol solution, a slurry of ethylene glycol, and the like.

As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or a slurry of ethylene glycol, a solution of crystalline germanium dioxide heated and dissolved in water or ethylene glycol was added thereto and heat-treated. A solution or the like is used. In particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution obtained by heating and dissolving germanium dioxide in water or a solution obtained by adding ethylene glycol to the solution and heating. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount of Ge compound used is 10 to 150 ppm, preferably 13 to 100 ppm, more preferably 15 to 7 ppm as the amount of Ge remaining in the polyester resin.
It is 0 ppm.

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

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

As the Al compound, aluminum formate, aluminum acetate, aluminum propionate,
Carboxylates such as aluminum oxalate, oxides, inorganic salts such as aluminum hydroxide, aluminum chloride, aluminum hydroxide chloride, and aluminum carbonate; aluminum alkoxides such as aluminum methoxide and aluminum ethoxide; and aluminum acetylacetonate. To
Examples thereof include aluminum chelate compounds with aluminum acetyl acetate and the like, organoaluminum compounds such as trimethylaluminum and triethylaluminum, and partially hydrolyzed products thereof. Of these, aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the residual amount of Al in the produced polymer is in the range of 5 to 200 ppm.

In the production of the polyester of the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination. The alkali metal compound or alkaline earth metal compound includes carboxylate such as acetate of these elements, alkoxide and the like, and is added to the reaction system as powder, aqueous solution, ethylene glycol solution and the like. The alkali metal compound or the alkaline earth metal compound is used in an amount of 1 to 50 p as a residual amount of these elements in the produced polymer.
pm.

Further, various P compounds can be used as a stabilizer. Examples of the P compound used in the present invention include phosphoric acid, phosphorous acid, and derivatives thereof. Specific examples include phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, monomethyl phosphate, dimethyl phosphate, monobutyl phosphate, dibutyl phosphate, and dibutyl phosphate. Phosphoric acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, etc., which may be used alone or in combination of two or more.
The P compound is 1 to 10 as a residual amount of P in the produced polymer.
It can be added at any stage of the polyester production reaction step so as to be in the range of 00 ppm.

The molten polyester obtained from the final polycondensation reactor is extruded into water from a die and cut in water, or is extruded into the atmosphere and then cut immediately while cooling with cooling water. And the like. Here, the melt polycondensation step (b) refers to a step from the end of the low polymer production step (a) to the step of chipping the molten polyester discharged from the final melt polycondensation reactor via a die. , A storage device for melting polycondensation chips such as silos.

The shape of the polyester chip may be any of a cylinder type, a square type, a spherical shape, a flat plate shape and the like.
The average particle size is usually 1.5 to 5 mm, preferably 1.
6 to 4.5 mm, more preferably 1.8 to 4.0 mm
Range. For example, in the case of a cylinder type, it is practical that the length is about 1.5 to 4 mm and the diameter is about 1.5 to 4 mm. In the case of spherical particles, the maximum particle diameter is 1.1 to 2.0 times the average particle diameter, and the minimum particle diameter is 0.1 to 2.0 times the average particle diameter.
It is practical that it is 7 times or more. Further, the weight of the chip is practically in the range of 15 to 30 mg / piece.

When the content of sodium, the content of magnesium, the content of silicon, and the content of calcium in the cooling water in the chipping step are N, M, S, and C, respectively, It is preferable that the melt polycondensation polyester is formed into chips so as to satisfy at least one of (4). N ≦ 1.0 (ppm) (1) M ≦ 0.5 (ppm) (2) S ≦ 2.0 (ppm) (3) C ≦ 1.0 (ppm) (4) Lower limit of these contents Is preferably independently 0.1 ppb or more for economic reasons. In addition, the particle size in cooling water 1
The particles having a particle size of ２５25 μm are preferably water containing 0.1 to 50,000 particles / 10 ml.

When cooling water outside the above conditions is used, these metal-containing compounds adhere to the polyester chip surface, and the final polyester obtained has a very high crystallization rate and large fluctuations. It is not preferable.

The intrinsic viscosity of the above melt polycondensation polyester can be set to a desired intrinsic viscosity depending on the application.
It is preferably 0.55 to 0.90 dl / g. It is more preferably 0.60 to 0.85 dl / g, and still more preferably 0.65 to 0.80 dl / g.

As described above, the melt polycondensation step (b)
Is sent to the water treatment step (d) or the solid phase polymerization step (f) described below.

When a low acetaldehyde content or a low cyclic trimer content is required, such as in the case of a low-flavor beverage heat-resistant container or a film for the inner surface of a metal can for beverages, the content is obtained in this manner. The melted polycondensed polyester is subjected to solid-state polymerization. The polyester is subjected to solid-state polymerization by a conventionally known method. First, the polyester subjected to the solid-phase polymerization is 100 to 210 under an inert gas or under reduced pressure, or under a steam or an inert gas atmosphere containing steam.
It is pre-crystallized by heating at a temperature of 1 to 5 hours. Then, at 190 to 230 ° C. under an inert gas atmosphere or under reduced pressure.
At a temperature of 1 to 30 hours. Here, the solid-phase polymerization step (f) refers to a step from the end of the chipping step to before the water treatment step (c), and may include a solid-state polymerization chip storage device such as a silo.

The intrinsic viscosity of the polyester according to the present invention, particularly the polyester whose main repeating unit is composed of ethylene terephthalate, is 0.55 to 1.30 deciliter / gram, preferably 0.58 to 1.20. Deciliter / gram, more preferably 0.60 to 0.90
It is in the range of deciliters / gram. Intrinsic viscosity 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 1.30 deciliters / gram, the resin temperature rises during melting by a molding machine or the like, and thermal decomposition becomes severe, so that free low-molecular-weight compounds that affect fragrance retention increase, Causes problems such as coloring of yellow.

The intrinsic viscosity of the polyester according to the present invention, in particular, the polyester whose main repeating unit is composed of ethylene-2,6-phthalate, is 0.40-1.
00 deciliters / gram, preferably 0.42-0.
95 deciliters / gram, more preferably 0.45
０．９0.90 deciliter / gram. If the intrinsic viscosity is less than 0.40 deciliter / gram, the obtained molded article or the like has poor mechanical properties. On the other hand, if it exceeds 1.00 deciliters / gram, the resin temperature rises during melting by a molding machine or the like, and thermal decomposition becomes severe, so that free low-molecular-weight compounds that affect fragrance retention increase, Causes problems such as coloring of yellow.

The polyester according to the present invention has an acetaldehyde content of 10 ppm or less, preferably 8 pp.
m or less, more preferably 5 ppm or less, and the formaldehyde content is 7 ppm or less, preferably 6 ppm or less, more preferably 4 ppm or less. When the content of acetaldehyde is 10 ppm or more and the content of formaldehyde is 7 ppm or more, the flavor and smell of the contents such as containers molded from the polyester composition become poor.

The amount of diethylene glycol copolymerized in the polyester according to the present invention is 1.0 to 5.0 mol%, preferably 1.3 to 4.5, of the glycol component constituting the polyester. Mol%, more preferably 1.5 to
4.0 mol%. Diethylene glycol content is 5.0
If it exceeds mol%, the thermal stability becomes poor, the molecular weight decreases during molding, and the acetaldehyde content and the formaldehyde content increase, which is not preferable. When the content of diethylene glycol is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.

Further, the cyclic 3 of the polyester according to the present invention
Content of the monomer is 0.50% by weight or less, preferably 0.4% by weight or less.
It is desirable that the content be 5% by weight or less, more preferably 0.40% by weight or less. When a heat-resistant hollow molded article or the like is molded from the polyester obtained by the production method of the present invention, heat treatment is performed in a heating mold, but the content of the cyclic trimer is 0.1%.
When the content is 50% by weight or more, the adhesion of the oligomer to the surface of the heating mold rapidly increases, and the transparency of the obtained hollow molded article or the like is extremely deteriorated.

Next, in the polyester obtained by the above-mentioned melt polycondensation step (b) or solid-phase polymerization step (f), when oligomers such as cyclic trimers are molded, the inner surface of the mold or the exhaust gas of the mold is exhausted. The polycondensation catalyst is deactivated in the water treatment step (c) in order to prevent mold stains and the like caused by adhering to the mouth, the exhaust pipe and the like. Examples of the catalyst deactivation treatment method for polyester include a method of subjecting a polyester chip to contact treatment with water, steam or a steam-containing gas after melt polycondensation or solid-phase polycondensation.

A method for treating the above-mentioned polyester chip with water, steam or a steam-containing gas will be described below.
Examples of the method of contact treatment with water include a method of immersing in water and a method of spraying water on a chip 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 150 ° C. 120 ° C. Hereinafter, a method for industrially performing water treatment will be described, but the method is not limited thereto. 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 the water treatment in a batch system, a silo-type treatment tank may be used. That is, the chips of the polyester are received in the silo in a batch system and water treatment is performed. In the case of treating the polyester chips with water in a continuous manner, the polyester chips can be continuously or intermittently received in the tower-type treatment tank from above and subjected to water treatment. This conceptual diagram is shown in FIG.

Regardless of whether the water treatment method is a continuous method or a batch method, the number of particles having a particle size of 1 to 25 μm existing in water introduced from outside the system is represented by X and sodium. When the content is N, the magnesium content is M, the calcium content C is silicon content, and at least one of the following (5) to (9) is satisfied, the water treatment is performed. Is desirable. 1 ≦ X ≦ 50000 (pcs / 10ml) (5) 0.001 ≦ N ≦ 1.0 (ppm) (6) 0.001 ≦ M ≦ 0.5 (ppm) (7) 0.001 ≦ C ≦ 0 0.5 (ppm) (8) 0.01 ≤ S ≤ 2.0 (ppm) (9)

By setting any of the number of particles in the water to be introduced into the water treatment tank and the content of sodium, magnesium, calcium, and silicon within the above ranges, a metal such as an oxide or a hydroxide called a scale is prepared. Contained substances float in the treated water, precipitate, adhere to the walls of the processing tank and piping, and adhere to and penetrate the polyester chips, which promotes crystallization during molding, resulting in poorly transparent bottles. Can be prevented.

A particle size of 1 to 25 μm used for water treatment is described below.
An example of a method for obtaining water containing 1 to 50,000 particles / 10 ml of the above particles will be described. As a method for reducing the number of particles in water to 50,000 particles / 10 ml or less, an apparatus for removing particles is installed at at least one or more places in a process until natural water such as industrial water is supplied to the treatment tank. Preferably, from the natural water sampling port to the processing tank including the above-mentioned processing tank, piping returning the water drained from the processing tank to the processing tank again, a fine removal device, and other auxiliary equipment necessary for water treatment. A device for removing particles is installed between them, and the particle size of
The content of particles of ２５25 μm is 1 to 50,000 particles / 10 m
It is preferably 1. Examples of the device for removing particles include a filter-filtration device, a membrane filtration device, a sedimentation tank, a centrifugal separator, and a foam entrainer. For example, a filter
If it is a filtration device, a belt filter system is used as a system,
Filtration devices such as a bag filter system, a cartridge filter system, a screen filter system, and a centrifugal filtration system may be used. Above all, for continuous operation, a belt filter
A filtration device of a system, a centrifugal filtration system, a bag filter system, or a screen filter system is suitable. In the case of a belt filter type filtration device, examples of the filter medium include paper, metal, cloth, and the like. Also, in order to efficiently remove particles and flow the treated water, the size of the filter is 5 to 5.
100 μm, preferably 10 to 70 μm, more preferably 15 to 40 μm.

In order to reduce the amount of sodium, magnesium, calcium and silicon in water from outside the system to the above-mentioned range, at least one or more places of sodium, magnesium, calcium and calcium in the process until industrial water is sent to the treatment tank. An apparatus for removing silicon is installed. Further, a filter is provided to remove clay minerals such as silicon dioxide and aluminosilicate which have become particulate. Examples of an apparatus for removing sodium, magnesium, calcium, and silicon include an ion exchange apparatus and an ultrafiltration apparatus.

Regardless of whether the water treatment method is continuous or batch, if all or most of the treated water discharged from the treatment tank is converted into industrial wastewater, a large amount of fresh water is required. In addition, there is a concern about the impact on the environment due to increased wastewater volume. That is, at least a part of the treated water discharged from the treatment tank is returned to the water treatment tank and reused, thereby reducing the required amount of water and reducing the effect on the environment by increasing the amount of wastewater. If the wastewater returned to the water treatment tank maintains a certain temperature,
Since the heating amount of the treated water can be reduced, the treated water discharged from the treated layer is preferably returned to the water treated layer and reused. Also, by reusing the water, the flow rate of the treated water in the treated layer can be increased, and as a result, the fines attached to the polyester chip can be washed away,
Also produces a fine removal effect. Here, the treated water that is discharged from the water treatment tank, returned to the treatment tank again, and reused includes water discharged from the overflow port of the water treatment tank and polyester chips from the treatment tank. There is treated water discharged and then separated from the chips.

However, the treated water discharged from the treatment tank in the water treatment contains fines that have already adhered to the polyester chips at the stage of receiving the polyester chips in the treatment tank, or the polyester chips or the walls of the treatment tank during the water treatment. Contains fines of polyester generated by friction. In addition, fresh treated water contains fine particles derived from inorganic substances, organic fine particles derived from spoiled plants and animals, and the like.

Therefore, when the treated water discharged from the treatment tank is returned to the treatment tank again and reused, the amount of fines and fine particles contained in the treated water in the treatment tank gradually increases, and the fines contained in the treated water are gradually increased. In some cases, fine particles adhere to the wall of the processing tank or the wall of the pipe to block the pipe.

Further, fines and fine particles contained in the treated water adhere to the polyester chip, and then the fine and fine particles adhere to or penetrate the polyester chip at the stage of drying and removing the water. The content becomes very large, and the polyester obtained in this way is promoted in crystallinity, the transparency of the obtained bottle is deteriorated, and the crystallinity at the time of crystallization of the bottle plug is too large. As a result, the dimensions of the plug part did not meet the standard, which sometimes resulted in poor capping of the plug part and leakage of the contents.

Therefore, according to the present invention, after being discharged from the water treatment tank, at least a part thereof is returned to the treatment tank again, and the particle size present in the treated water to be recycled is 1 to 40 μm.
m of particles 100,000 particles / 10 ml or less, preferably 80,000 particles / 10 ml or less, more preferably 500,000 particles / 10 ml or less.
It is desirable to keep the number at or below 00/10 ml. Here, the treated water returned to the treatment tank and reused in this way is referred to as recycled water.

The particle size of the recycled water is 1 to 40
A method for reducing the number of particles of μm to 100,000 / 10 ml or less will be exemplified, but the present invention is not limited thereto. The number of particles having a particle size of 1 to 40 μm
As a method of reducing the volume to 10 ml or less, a device for removing fines and fine particles is installed at at least one or more places in the process until the treated water discharged from the treatment tank is returned to the treatment tank again. Examples of the device for removing fines and fine particles include a filter-filtration device, a membrane filtration device, a sedimentation tank, a centrifugal separator, and a foam entrainer. For example, in the case of a filter-filtration apparatus, examples of the method include a filtration apparatus such as an automatic self-cleaning method, a belt filter method, a bag filter method, a cartridge filter method, and a centrifugal filtration method. Above all, a belt filter system, a centrifugal filtration system, and a bag filter system are suitable for continuous operation. In the case of a belt filter type filtration device, examples of the filter medium include paper, metal, cloth, and the like. In addition, in order to efficiently remove fines and flow treated water, the size of the filter is 5 to 100 μm, preferably 5 to 70 μm.
More preferably, the thickness is 5 to 40 μm.

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

When the polyester chips are brought into contact with water vapor or a gas containing water vapor for treatment, 50 to 50%
Steam or steam-containing gas or steam-containing air at a temperature of 150 ° C., preferably 50 to 110 ° C., is preferably supplied or present in an amount of 0.5 g or more as steam per kg of granular polyethylene terephthalate. The granular polyethylene terephthalate is brought into contact with steam. The contact between the polyester chips and water vapor is usually performed for 10 minutes to 2 days, preferably for 20 minutes to 10 days.
Done for hours.

A method for industrially carrying out the contact treatment of granular polyethylene terephthalate with water vapor or a gas containing water vapor will be exemplified below, but the method is not limited thereto. The processing method may be either a continuous method or a batch method.

When a polyester chip is subjected to a contact treatment with steam in a batch system, a silo-type treatment apparatus may be used. That is, a polyester chip is received in a silo, and steam or a steam-containing gas is supplied in a batch system to perform a contact treatment. When polyester chips are to be continuously treated with steam, the granular polyethylene terephthalate is continuously received from the top in a tower-type treatment device, and steam is continuously supplied in parallel or countercurrent to make contact treatment with steam. Can be.

As described above, the granular polyethylene terephthalate treated with water or steam is drained by a draining device such as a vibrating sieve or a simmon cutter, and is transferred to the next drying step as required.

For drying the polyester chips which have been subjected to the contact treatment with water or steam, a commonly used polyester drying treatment can be used. As a method for continuous drying, a hopper-type through-air dryer that supplies a polyester chip from the upper portion and allows a drying gas to flow from the lower portion is usually used. Drying can also be performed by a rotating disk type continuous dryer that supplies a heating medium or the like to a rotating disk or an outer jacket.

When drying in a batch mode, use a double coat
Drying may be performed under reduced pressure using a rotary dryer or under atmospheric pressure while drying gas is passed. As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferable, and dry nitrogen is particularly preferable from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of polyester. Here, the water treatment step (c) refers to a step from a treatment apparatus for performing contact treatment with water to cooling of chips after drying.

Next, in order to increase the crystallization rate of the molded product obtained from the polyester treated in the water treatment step (c) and suppress the fluctuation, the polyester obtained by the melt polycondensation as described above, Or the polyester obtained by melt polycondensation and subsequent solid phase polymerization,
After the treatment in the water treatment step (c), a contact treatment with a member made of a crystalline thermoplastic resin in a chip form is performed.

As a method for bringing the polyester into contact with the member made of the crystalline thermoplastic resin, it is preferable that the polyester is brought into collision with the member in the space where the member made of the crystalline thermoplastic resin exists. Specifically, for example, immediately after the melt polycondensation of the polyester or immediately after the solid-phase polymerization, or when filling or discharging from a container for transportation in the transportation stage of the polyester product, or molding the polyester At the time of injection of the molding machine at the stage, a part of a pneumatic transport pipe, a gravity transport pipe, a silo, a magnet part of a magnet catcher or the like in the stage is made of the crystalline thermoplastic resin or the crystal. By lining a thermoplastic resin or by installing a member made of a crystalline thermoplastic resin such as a rod, plate, or net in the transfer path. Method of transferring the ester. The contact time of the polyester with the member is usually as short as about 0.01 second to several minutes, but a trace amount of the crystalline thermoplastic resin can be mixed with the polyester.

The polyolefin resin used in the present invention includes a polyethylene resin, a polypropylene resin, and an α-olefin resin.

The polyethylene resin used in the present invention includes, for example, a homopolymer of ethylene, ethylene and propylene, butene-1,3-methylbutene-
Other α-olefins having about 2 to 20 carbon atoms such as 1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, decene-1, and the like, vinyl acetate, vinyl chloride,
Derivatives of unsaturated carboxylic acids such as acrylic acid and methacrylic acid, derivatives of unsaturated carboxylic acids such as acrylates and methacrylates, styrene-based hydrocarbons such as styrene, glycidyl acrylate, glycidyl methacrylate and the like Copolymers with a vinyl compound such as an unsaturated epoxy compound are exemplified. Specifically, for example, ultra low, low, medium,
Ethylene homopolymer such as high-density polyethylene (branched or linear), ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-methylpentene-1 copolymer, ethylene-hexene- Ethylenes such as 1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer Resins.

Examples of the polypropylene resin used in the present invention include, for example, propylene homopolymer, propylene and ethylene, butene-1,3-methylbutene-1, pentene-1,4-methylpentene-1,
Carbon number 2 such as hexene-1, octene-1 and decene-1
~ 20 other α-olefins, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, copolymers with vinyl compounds such as styrene, or hexadiene, octadiene,
Copolymers with diene such as decadiene and dicyclopentadiene are exemplified. Specific examples include propylene-based resins such as propylene homopolymer (atactic, isotactic, syndiotactic polypropylene), propylene-ethylene copolymer, and propylene-ethylene-butene-1 copolymer.

Examples of the α-olefin resin used in the present invention include a homopolymer of an α-olefin having about 2 to 8 carbon atoms such as 4-methylpentene-1, those α-olefins, ethylene and propylene. , Butene
1,3-methylbutene-1, pentene-1, hexene-
And copolymers with other α-olefins having about 2 to 20 carbon atoms, such as 1, octene-1 and decene-1. Specifically, for example, butene-1 homopolymer, butene-1
- ethylene copolymer, and polybutene-based resins butene-1-propylene copolymer, 4-methylpentene-1 homopolymer, 4-methylpentene-1 co with α- olefins C ₂ -C ₁₈ Polymethylpentene resins such as polymers,
And the like.

The polyamide resins used in the present invention include, for example, butyrolactam, δ-valerolactam, ε-caprolactam, enantholactam, ω
-Polymers of lactams such as laurolactam, polymers of aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine Aliphatic diamines such as undecamethylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-amino Alicyclic diamines such as cyclohexylmethane), diamine units such as aromatic diamines such as m- or p-xylylenediamine, and aliphatic dicarboxylic acids such as glutaric acid, adipic acid, suberic acid and sebacic acid, and cyclohexanedicarboxylic acid And other alicyclic dicarboxylic acids, terephthalic acid, isophthalic acid, etc. Polycondensates of a dicarboxylic acid units such as aromatic dicarboxylic acids, and copolymers thereof and the like can be mentioned, specifically, for example, nylon 4, nylon 6, nylon 7, nylon 8, nylon 9, nylon 1
1, 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 / 6T, nylon 6I / 6T and the like.

The polyacetal resin used in the present invention includes, for example, polyacetal homopolymers and copolymers. The polyacetal homopolymer has a density of 1.40 to 1.42 g / cm ^{3 as} measured by ASTM-D792, and ASTM D-12.
The melt flow ratio (MFR) measured at 190 ° C. under a load of 2160 g by the measurement method of Example No. 38 was 0.5 to 50 g / 10.
Polyacetals in the range of minutes are preferred.

The polyacetal copolymer includes:
The density measured by the method of ASTM-D792 is 1.
A polyacetal copolymer having a melt flow ratio (MFR) measured at a temperature of 190 ° C. and a load of 2160 g in a range of 0.4 to 50 g / 10 minutes by a measurement method of 38 to 1.43 g / cm ³ and ASTM D-1238 is obtained. preferable. Examples of these copolymer components include ethylene oxide and cyclic ether.

The polybutylene terephthalate resin used in the present invention includes, for example, a polybutylene terephthalate homopolymer composed of terephthalic acid and 1,4-butanediol, naphthalenedicarboxylic acid,
Copolymers obtained by copolymerizing diethylene glycol, 1,4-cyclohexanedimethanol, and the like are included.

The mixing ratio of the crystalline thermoplastic resin used in the present invention to the polyester is 0.1 p.
pb to 1000 ppm, preferably 0.3 ppb to 10
0 ppm, more preferably 0.5 ppb to 1 ppm, still more preferably 0.5 ppb to 45 pbb. If the compounding amount is less than 0.1 ppb, the crystallization rate becomes extremely slow, and the crystallization of the plug portion of the hollow molded article becomes insufficient. The capping is poor because it does not fall within the value range, and the stretch heat-fixing mold for molding the heat-resistant hollow molded article is heavily stained, and frequent cleaning is required to obtain a transparent hollow molded article. There must be. Also 1000p
If it exceeds pm, the crystallization speed is increased, and the crystallization of the plug portion of the hollow molded article becomes excessively large. As a result, the amount of shrinkage and shrinkage of the plug portion does not fall within the specified value range, resulting in poor capping. Leakage, or whitening of the preform for a hollow molded body, making normal stretching impossible. In the case of a sheet-like material, if it exceeds 1000 ppm, the transparency becomes extremely poor, and the stretchability becomes poor, so that normal stretching is impossible, and only a stretched film having large thickness unevenness and poor transparency can be obtained. I can't.

When the above-mentioned member made of crystalline thermoplastic resin is contacted with polyester, it is desirable that the crystalline thermoplastic resin is present in a state of being attached to the surface of the polyester chip. Depending on the magnitude of the impact force at the time of collision with the member or the compression force at the time of contact, or the properties of the crystalline thermoplastic resin member such as impact resistance and peeling resistance, the crystalline thermoplastic resin member In some cases, the polyester chip is mixed with the contact-treated polyester chip without being attached to the polyester chip, that is, in a state independent of the polyester chip. The molded product obtained from the polyester in such a mixed state has a very high crystallization rate or a very large fluctuation in the rate.
In the case of a preform for a hollow molded article, the whitening and transparency unevenness are severe, and normal stretching is impossible, and only a hollow molded article having a large thickness unevenness and poor transparency can be obtained. In addition, although usually present as fine fine particles, sometimes the average particle diameter is about 0.5 to several mm in the form of granules or lumps having a size independent of the polyester chips and the contact-treated polyester described above. It may be mixed in. In such a case, the crystalline thermoplastic resin becomes a foreign substance in the obtained molded product, and as a result, the obtained molded product has many defects such as uneven thickness, voids, and whitening. . Therefore, it is desirable to remove the fine granules, granules and lumps of the crystalline thermoplastic resin existing independently of the polyester chips before molding.

The following method can be used as a method for separating and removing the fine granular material, granular material or lump of the crystalline thermoplastic resin from the polyester treated in the contact treatment step (d). That is, the molten polycondensation polyester or the solid-phase polymerized polyester treated in the water treatment step (c) is contact-treated with a member made of a crystalline thermoplastic resin, and then treated in a vibration sieving step, an airflow classification step using an air flow, or the like. These fine-grained, granular and massive crystalline thermoplastic resins are removed by a treatment method such as a washing method using ion-exchanged water or a method of performing a floating separation treatment. Such a method of separating and removing the fine granular material, the granular material and the lump of the crystalline thermoplastic resin is also effective as a method of removing the fine or film-like polyester material described later.

Usually, the melt-polycondensed polyester is formed into chips and then transported through a transport pipe to a storage silo or the like, or subjected to a solid phase polymerization step (f), a water treatment step (c), It is transported to the next step such as the step (d) of contact treatment with a member made of a thermoplastic resin. The solid-phase polymerized polyester chips are also transported to the next step or a silo for storage. When such chips are transported by, for example, a forced low-density transport method using air, a large impact force is applied to the surface of the polyester chips by collision with the piping, and as a result, fine or film-like materials are produced. Occurs in large quantities. Such a fine or film-like substance has an effect of accelerating the crystallization of polyester, and when it is present in a large amount, the transparency of the obtained molded article becomes extremely poor. Further, such fine or film-like materials include those having a melting point higher than the normal melting point by about 10 to 20 ° C. or more. In addition, even when solid-phase polymerization is performed using a rotary solid-state polymerization device, or when a feeding device that applies impact force or shear force to a polyester chip is used, the melting point is about 10 to 20 ° C. or more higher than a normal melting point. A very large amount of fine or film-like material having a melting point is generated. this is,
It is presumed that the chip generates heat due to a large force such as an impact force applied to the chip surface, and at the same time, the oriented crystallization of polyester occurs on the chip surface, resulting in a dense crystal structure.

The melting point of the fine and the like is measured by the following method using a differential scanning calorimeter (DSC). The melting polycondensed polyester chip usually has one melting point, and the solid-phase polymerized polyester has a melting point of one chip. The melting point may be one or two depending on solid-state polymerization conditions. On the other hand, the melting peak temperature indicating the melting point of fine or the like is constituted by one or more melting peaks.
When there is one melting peak, the peak temperature is used. When there are a plurality of melting peaks, the highest one of the plurality of melting peaks is defined as " The peak temperature on the highest side of the melting peak temperature of fine or the like is referred to as "the melting point of fine or the like" in Examples and the like.

Approximately 10 to 20 from the above normal melting point
When a fine or film-like material of polyester having a melting point higher than ° C. is subjected to solid-state polymerization treatment together with a polyester chip, the melting point becomes higher than before these treatments. Even in the case of fine or film-like materials having a melting point not higher than the normal melting point by about 10 ° C. or more, the above-mentioned treatments make these melting points about 10 to 20 lower than the normal melting point.
It has a melting point higher than ℃. It is presumed that this is because these treatments change the crystal structure to a more dense crystal structure.

About 10 to 20 ° C. above such a normal melting point
When a polyester containing a fine or film-like material having a high melting point is molded under ordinary molding conditions, the crystals do not completely melt during melt molding and remain as crystal nuclei. As a result,
Since the crystallization rate during heating is increased, the crystallization of the plug portion of the hollow molded container becomes excessive, so that the amount of shrinkage of the plug portion does not fall within the specified value range, and the cap portion of the plug portion becomes defective and the content becomes poor. There is a problem that leakage occurs.
In addition, the preform for hollow molding is whitened, so that normal stretching cannot be performed, thickness unevenness occurs, and the transparency of the obtained hollow molded body is deteriorated due to a high crystallization rate. Fluctuations are also large.

In general, the polyester contains about 1 to about 1000 ppm of fines having a melting point higher than the normal melting point by about 10 to 20 ° C. or more and fines including film-like substances, depending on the production method. In addition, such fines and the like do not exist in the polyester chip in a uniform mixed state but are unevenly distributed. Therefore, when such a polyester is subjected to a contact treatment under flow conditions with a member made of a crystalline thermoplastic resin having a melting point of polyethylene or the like, the crystallization speed is further increased, but only the polyester whose speed greatly varies is obtained. It is not a problem.

Further, in the case of polyester in which the main repeating unit is ethylene terephthalate, it is obtained in the case where the above-mentioned fine or film-like material whose melting peak temperature on the highest temperature side exceeds 265 ° C. is contained. The crystallization speed of the resulting polyester becomes too fast, and the fluctuation thereof becomes very large, which is problematic.

Therefore, the process for producing a polyester according to the present invention comprises the step (a) of producing a low polymer in which an aromatic dicarboxylic acid or a functional derivative thereof is esterified or transesterified with a glycol or a functional derivative thereof; A melt polycondensation step (b) of melt-polycondensing the low polymer obtained in the low polymer production step, a water treatment step (c) of contacting the polyester obtained in the melt polycondensation step with water, A contact treatment step (d) of contacting the polyester obtained in the treatment step with a member made of a crystalline thermoplastic resin, and removing fines and / or the like from the polyester obtained in the contact treatment step by removing fine and / or film-like materials. (E) a process for producing a polyester, comprising: It solves the above problems by treating with Ain such removal step (e).

The method for producing the polyester of the present invention comprises:
Aromatic dicarboxylic acid or its functional derivative and glyco-
(A) a low-polymer production step of esterifying or transesterifying a low polymer or a functional derivative thereof, a melt polycondensation step (b) of melt-polycondensing the low polymer obtained in the low polymer production step, A solid phase polymerization step (f) for solid-phase polymerization of the polyester obtained in the melt polycondensation step, a water treatment step (c) of contacting the polyester obtained in the solid phase polymerization step with water, A contact treatment step (d) of contacting the obtained polyester with a member made of a crystalline thermoplastic resin, and a fine removal step (e) of removing fine and / or film-like substances from the polyester obtained in the contact treatment step. ), Wherein the polyester that has been contact-treated with the member made of the crystalline thermoplastic resin is treated in the fine or similar removing step (e). Thus in the same manner as described above solves the above problems.

The low polymer production step (a), melt polycondensation step (b), water treatment step (c), and contact treatment step (d)
And all steps of fine and the like removal step (e), or low polymer production step (a), melt polycondensation step (b), solid phase polymerization step (f), water treatment step (c), contact treatment step (d) )
And all of the fine and the like removing step (e) may be operated continuously, or for example, a low polymer production step (a), a melt polycondensation step (b), a solid phase polymerization step (f) And the water treatment step (c) are continuously operated, and the obtained polyester is temporarily stored in a storage silo or the like, and after a certain period of time, is subjected to the contact treatment step (d) and the fine etc. removal step (e). Processing may be performed.

Further, the content of any 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 polyester treated in the fine etc. removing step (e) is reduced. , 300 ppm or less,
Preferably not more than 200 ppm, more preferably 100p
The above problem can be further solved by reducing the concentration to pm or less, more preferably 50 ppm or less.

In the fine or the like removing step (e), the fine particles, granules or lumps of the crystalline thermoplastic resin, which are present independently of the polyester chips, are removed. Can also be reduced.

The fine content, film-like content of the polyester treated in the fine etc. removing step (e),
Alternatively, if the content of any of the fine content and the total content of the film-like material content exceeds 300 ppm, the crystallization rate during heating of the molded article from the obtained polyester is increased, so that the hollow molding container The crystallization of the plug portion becomes excessive, so that the shrinkage amount of the plug portion does not fall within the specified value range, and there is a problem that the cap portion of the plug portion becomes defective and the contents leak. In addition, the preform for hollow molding is whitened, so that normal stretching cannot be performed, thickness unevenness occurs, and the transparency of the obtained hollow molded body is deteriorated due to a high crystallization rate. Fluctuations are also large.

In the case of polyester whose main repeating unit is ethylene terephthalate, the melting peak of the fine and / or film-like substance contained in the polyester treated in the fine etc. removing step (e) is used. If the peak temperature on the highest temperature side exceeds 265 ° C., the crystallization speed of the obtained polyester becomes too fast, and the fluctuation thereof becomes extremely large, which is problematic.

Therefore, according to the present invention, the highest peak temperature of the melting peak temperature of the fine and / or film-like substance contained in the polyester treated in the fine or the like removing step (e) is 265. The above-mentioned problem is solved even more by setting the temperature to not more than ° C.

The method for separating and removing fine and / or film-like substances from the polyester obtained in the contact treatment step (d) includes the following methods. That is, in the case of the melt polycondensed polyester, a method in which the polyester is subjected to a vibration sieving step and an air flow classification step using an air stream immediately before or after contacting the polyester with a member made of a crystalline thermoplastic resin, or There is a method of treating in a washing step using exchanged water. In the case of solid-phase polymerization polyester, the solid-phase polymerization step (f)
Immediately before and immediately before and immediately after the step of contact treatment with the member made of the crystalline thermoplastic resin, a vibrating sieve step and an airflow classification step by an air flow separately installed, etc.
Alternatively, a method of performing treatment in a water washing step using ion-exchanged water and the like can be given.

As one of the methods for preventing the inclusion of fine and / or film-like substances having a peak temperature on the highest side of the melting peak temperature of the fine or the like exceeding 265 ° C. After the contact treatment with the thermoplastic resin, a method of treating in a fine or the like removing step as described above may be used.

It is also necessary to pay attention to the content and properties of fine and film-like substances contained in the polyester before the contact treatment with the member made of the crystalline thermoplastic resin for the above and the following reasons. It is. For example, in the case of a melt polycondensed polyester, the melt polycondensed polyester supplied to the contact treatment step (d) is fine and / or a peak having a peak temperature on the highest side of the melting peak temperature exceeding 265 ° C. The object can also be achieved by not including a film-like material.

In the case of the solid-phase polymerized polyester, the molten polycondensed polyester supplied to the solid-phase polymerization step (f) and the solid-phase polymerized polyester supplied to the contact treatment step (d) after the solid-phase polymerization are: The object can also be attained by not including a fine and / or film-like substance whose peak temperature on the highest side of the melting peak temperature exceeds 265 ° C.

The polyester chips that have been subjected to the water treatment step (c) are more brittle than the chips before the contact treatment with water. A contact processing step (f) of contacting a crystalline thermoplastic resin member having a melting point of 250 ° C. or less by using a rotary feeder such as a die or a forced low-density transport method using air. When transported through a transportation pipe, fine or film-like substances are generated in a very large amount, and the content thereof sometimes becomes 1000 ppm or more with respect to the polyester chips. In particular, the longer the contact processing time or the higher the processing temperature, the greater the amount of fines and the like generated. Moreover, such fines and the like are not uniformly mixed and present in the polyester chip, but are unevenly distributed. Therefore, the crystallization rate at the time of heating of a molded article from a polyester obtained by performing a contact treatment with a member made of a crystalline thermoplastic resin having a melting point of polyethylene or the like of 250 ° C. or less as described below with such a polyester is fast. However, because the content of fines and the like greatly fluctuates, and the amount of the crystalline thermoplastic resin adhered to the polyester surface fluctuates greatly, the crystallization speed and the transparency of the molded product fluctuate very much. Becomes a problem.

Therefore, the polyester treated in the water treatment step (c) is transported to a fine or similar removing step for separating and removing fine and / or film-like materials, and comes into contact with the member made of the crystalline thermoplastic resin. It is important to remove these as much as possible before processing.

As a countermeasure for this, an intermediate step between the melt polycondensation step (b) and the water treatment step (c) and / or an intermediate step between the water treatment step (c) and the contact treatment step (d) may be used. It is desirable to add a fine removal step (g) for removing fine and / or film-like materials.

Further, an intermediate step between the melt polycondensation step (b) and the solid phase polymerization step (f), an intermediate step between the solid phase polymerization step (f) and the water treatment step (c), or the water treatment step (c) It is preferable to add a fine removal step (g) for removing fine and / or film-like materials to at least one intermediate step of the intermediate step of the contact treatment step (d).
As the fine removal step (g), the same method as described above can be used.

The production method of the present invention is characterized in that the fine content of the polyester supplied to the water treatment step (c), the contact treatment step (d) or the solid phase polymerization step (f), the film content, Alternatively, the content of any one of the total content of the fine content and the film content is set to 300 p.
pm, preferably 200 ppm or less, more preferably 100 ppm or less, and still more preferably 50 ppm or less.

Further, the production method of the present invention is characterized in that fine and / or film-like polyester contained in the polyester supplied to the water treatment step (c), the contact treatment step (d) or the solid phase polymerization step (f) is provided. The above problem is further solved by setting the peak temperature on the highest side of the melting peak temperature of the product to 265 ° C. or less.

A specific example of a method for preventing the polyester before the contact treatment with the crystalline thermoplastic resin from containing fines having such a high melting point will be described below. In the case of melt polycondensation polyester, after melt polycondensation, the molten polyester is extruded into water from a die and cut in water, or extruded into the atmosphere, and then cut into chips immediately after cooling with cooling water to form chips. After draining the polyester chips formed into chips, a vibrating sieve process and an air flow classification process by air flow,
Alternatively, chips, fines and film-like materials having a shape other than a predetermined size are removed by a water washing process, and sent to a storage tank by a plug transport system or a bucket type conveyor transport system. The removal of chips from the tank can be done with a screw.
According to the formula feeder, the powder is transported to the next step by a plug transport method or a bucket type conveyor transport method, and immediately before or immediately after the contact treatment step (d), an air flow classification step by an air flow,
Alternatively, a fine washing process is performed by providing a washing process. In the case of solid-phase polymerized polyester, the molten polycondensed polyester which has been subjected to the above-mentioned fine or film-like material removal treatment is again subjected to an air flow classification step by an air flow immediately before the solid-phase polymerization step (f), or a water washing treatment. Fine and film-like substances are removed by the process, and the solid phase polymerization process (f)
To It is also important to use a solid-state polymerization apparatus that does not impact or shear the chip, particularly its surface. When transporting the melt-polycondensed prepolymer chips to the solid-state polymerization facility, or when transporting the polyester chips after the solid-phase polymerization to the sieving step, the contact treatment step (d), the storage tank, or the like, these transports are required Most of them adopt plug transport system or bucket type conveyor transport system. Chips are extracted from crystallization equipment and solid state polymerization reactor using screw feeder. Use a device that can minimize the impact with the equipment and transportation piping.

The gas that comes into contact with the polyester before the contact treatment with the member made of the crystalline thermoplastic resin and / or after the contact treatment with the member made of the crystalline thermoplastic resin is 0.3 to 5 μm in particle diameter. Is less than 1,000,000 (pieces / cubic foot), preferably less than 500,000 (pieces / cubic foot), and more preferably 100000
It is desirable to use the following gas (individual / cubic) introduced from outside the system. Particles having a particle diameter of more than 5 μm in the gas are not particularly limited, but are preferably 5 μm.
(Pieces / cubic feet) or less, more preferably 1 (pieces / cubic
Cubic feet).

In the polyester production process, containers such as a silo, a hopper of a molding machine, a container for transportation, etc., from a melt polycondensation process, a solid-phase polymerization process, etc., through respective processes such as a sieving process, an airflow classification process, etc. The polyester is transported and dried between these steps by generally using air near the processing equipment by a blower or the like for the steps. Conventionally, such air is used without any treatment, or according to JIS B 9908 (199).
In general, it was used only by processing with a purifier equipped with a low-performance filter unit such as type 3 specified in 1). However, the polyester treated in such a process sometimes has a problem that only a molded article having poor transparency can be obtained. Particularly, before and after the contact treatment step with the member made of the crystalline thermoplastic resin, if air of the above-described quality is used as the gas that comes into contact with the polyester, the crystallization speed, transparency, etc. Fluctuations are large, and there is a high possibility that problems will occur.

Therefore, in the process for producing polyester by contact treatment with the member made of the crystalline thermoplastic resin according to the present invention, the process is carried out immediately before the step of separating and removing the fine and / or film-like material, and in the subsequent steps. Particles having a particle size of 0.3 to 5
1 to 1,000,000 μm particles (pieces / cubic foot)
It is preferable to use a gas introduced from outside the system.

It is to be noted that particles having a particle diameter of less than 0.3 μm in the gas are not particularly limited, but smaller particles are preferable in order to obtain a resin which gives a transparent molded body.
The number of particles having a particle size of less than 0.3 μm is preferably 100
00000 (pieces / cubic feet) or less, more preferably 500000 (pieces / cubic feet) or less, still more preferably 2,000,000 (pieces / cubic feet or less).

Hereinafter, a method for controlling the number of particles having a particle size of 0.3 to 5 μm in a gas introduced from outside the system to 1,000,000 (pieces / cubic feet) or less will be exemplified, but the present invention is not limited to this. It does not do.

Particle size in gas introduced from outside the system 0.3 to 5
As a method of reducing the number of particles of μm to 1,000,000 (pieces / cubic foot) or less, cleaning is performed by removing the particles in at least one place in the process until the gas introduced from outside the system comes into contact with the polyester chip. Install the equipment. When the gas is air near the processing equipment, JIS B 9908 (19) is used during the process until the air introduced from the air intake port by the blower comes into contact with the polyester chip.
A gas purifier equipped with a type 1 and / or type 2 filter unit specified in 91) is installed, and the number of particles having a particle size of 0.3 to 5 μm in the air is 1,000,000 (pieces / cubic feet). It is preferable to set the following.

Further, JIS B9 was inserted into the air intake port.
908 (1991), it is possible to extend the life of the filter unit by installing a gas purifier equipped with a type 3 filter unit and using the gas purifier equipped with the filter unit. It is.

JIS B 99 for removing particles in gas
As a material of an ultra-high performance filter (hereinafter abbreviated as a HEPA filter) unit of the type 1 specified in JP 08 (1991), a filter paper made of glass fiber is cited.

Also, JIS B 9908 (1991)
Examples of the material of the high-performance filter unit of the type 2 specified in the above include a filter made of a polypropylene fiber and a filter made of a laminate of a polytetrafluoroethylene film and a PET fiber cloth. 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 by the above include a nonwoven fabric made of PET or polypropylene.

The polyester used in the present invention may optionally contain other additives, for example, a known ultraviolet absorber,
Antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from outside and lubricants deposited inside during the reaction, mold release agents, nucleating agents,
Various additives such as a stabilizer, an antistatic agent, a dye, and a pigment may be blended. The polyester obtained by the production method of the present invention is injection-molded and stretch blow-molded to form a stretched hollow molded article, and extruded to form a sheet-like material.

[0129]

EXAMPLES The present invention will be described below in more 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) Polyethylene diethylene glyco-
The content was decomposed by methanol and the amount of DEG was quantified by gas chromatography and expressed as a ratio (mol%) to the total glycol components.

(3) Content of polyester cyclic trimer (hereinafter referred to as "CT content") A sample is dissolved in a mixed solution of hexafluoroisopropanol / chloroform, and further diluted with chloroform. After adding methanol to precipitate a polymer, the mixture is filtered. The filtrate was evaporated to dryness, made up to a constant volume with dimethylformamide, and the cyclic trimer composed of ethylene terephthalate units was quantified by liquid chromatography.

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

(5) Increase in amount of cyclic trimer during melting of polyester (ΔCT amount) 3 g of a dried polyester chip was placed in a glass test tube, immersed in an oil bath at 290 ° C. for 60 minutes under a nitrogen atmosphere, and melted. Let it. The amount of increase of the cyclic trimer at the time of melting is determined by the following equation. Cyclic trimer increase during melting (% by weight) = Cyclic 3 after melting
Monomer content (% by weight) -cyclic trimer content before melting (% by weight)

(6) Measurement of Fine Content and Film-like Material Content About 0.5 kg of the resin is referred to 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) equipped with a 2 mm wire mesh was placed on a sieve combined in two stages, and sieved at 1800 rpm for 1 minute with a rocking sieve tow machine SNF-7 manufactured by Teraoka. This operation was repeated to sieve a total of 20 kg of the resin. In the case where two or more chips fused to each other or chips cut to a size larger than a normal shape are captured on the sieve (A) separately from the film-like material, The remaining film-like material from which the water was removed and the fines sieved under the sieve (B) were separately washed with ion-exchanged water and collected by filtration through a G1 glass filter manufactured by Iwaki Glass Co., Ltd. These are put together with a glass filter in a dryer at 100 ° C
, And then cooled and weighed. The same operation of washing and drying with ion-exchanged water was repeated again, and it was confirmed that the weight became constant. The weight of the glass filter was subtracted from this weight to obtain the fine weight and the weight of the film.
The fine or film content is the fine weight or film weight / the total resin weight sieved. The total content is determined from these values.

(7) Measurement of melting point of fine and film-like materials Differential scanning calorimeter (DS) manufactured by Seiko-Electronic Industries Co., Ltd.
C), measured using RDC-220. In (6),
Fine or film-like materials collected from 20 kg of polyester were dried under reduced pressure at 25 ° C. for 3 days, and DSC measurement was performed at a heating rate of 20 ° C./min using 4 mg of a sample for one measurement. The melting peak temperature on the highest side of the peak temperature is determined. The measurement is performed on a maximum of 10 samples, and the average value of the melting peak temperature on the highest temperature side is obtained.

(8) Average Density of Polyester Chip and Density of Preform Plug Portion The density was measured at 30 ° C. using a density gradient tube of a calcium nitrate / water mixed solution.

(9) Haze (haze degree) and haze spots Samples were cut from the body (thickness of about 0.45 mm) of the molded article (5 mm thick) and the hollow molded article (13) below. Haze meter manufactured by Nippon Denshoku Co., Ltd., modelNDH
Measured at 2000. In addition, a molded plate molded 10 times continuously
The haze of the sample (wall thickness: 5 mm) was measured, and the haze unevenness was determined as follows. Haze spot = maximum value of haze / minimum value of haze

(10) Density increase due to heating of the preform plug portion The preform plug portion was heat-treated for 60 seconds with a homemade infrared heater, and a sample was taken from the top surface and the density was measured.

(11) Unevenness of thickness of bottle Four samples (3 cm × 3 cm) were randomly cut from the center of the body of the hollow molded article of (13) described later, and the thickness was measured with a digital thickness gauge (within the same sample). Was measured at five points, and the average was taken as the sample thickness). The thickness unevenness was determined as follows. Thickness unevenness = maximum thickness / minimum thickness

(12) Molding of Stepped Molded Plate The dried polyester was dried with a Meiki Seisakusho M-150C (D
M) A stepped flat mold (surface temperature of about 2 ° C.) cooled by water of 10 ° C. at a cylinder temperature of 285 ° C. by an injection molding machine.
(2 ° C.). The resulting stepped plate is 2,
A plate having a thickness of about 3 cm × about 5 cm square having a thickness of 3, 4, 5, 6, 7, 8, 9, 10, 11 mm is provided in a stepwise manner, and each piece weighs about 146 g. Plates having a thickness of 5 mm are used for measuring haze (haze%).

(13) Molding of Hollow Molded Product The polyester was dried with a dryer using dehumidified air, and a preform was molded at a resin temperature of 287 ° C. with an M-150C (DM) injection molding machine manufactured by each machine. . This preform
The spout was heated and crystallized by a home-made spout crystallizer. Next, this preformed body was biaxially stretched and blown at a magnification of about 2.5 times in the vertical direction and about 3.8 times in the circumferential direction using an LB-01E molding machine manufactured by COPOPLAST, and subsequently about 150 times.
C. for about 7 seconds in a mold set at
A 0 cc container (body thickness 0.45 mm) was molded. The stretching temperature was controlled at 100 ° C.

(14) Evaluation of Leakage of Contents from Hollow Molded Article The hollow molded article molded in (13) above was filled with hot water at 90 ° C., capped by a capping machine, the container was turned over, and the contents were left to stand. Was examined for leaks. The deformation of the plug after capping was also examined.

(15) Sodium content, calcium content, magnesium content, and silicon content in the cooling water in the chipping process and the water introduced in the water treatment process The cooling water and the water introduced after particle removal and ion exchange have been collected. After filtration through a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., the filtrate was measured with an inductively coupled plasma emission analyzer manufactured by Shimadzu Corporation.

(16) Measurement of the Number of Particles in Introduced Water and Recycled Water Particle measurement of the introduced water from which particles have been removed and ion-exchanged or the recycled water treated in the filtration device (5) and the adsorption tower (8) is performed by a light blocking method. Is measured using a PAC 150 manufactured by Seishin Enterprise Co., Ltd.
Displayed in ml.

(17) Measurement of the number of particles in the gas that comes into contact with the polyester chip The gas sent by a blower or the like for forcedly sending the gas and passing through the gas cleaning device is branched into the main gas stream before coming into contact with the chip. Then, it is introduced into a particle measuring instrument and measured. The measurement is repeated five times, the average value is obtained, and the number per cubic foot of gas is calculated. As a particle measuring device, a light scattering type particle measuring device manufactured by Rion Co., Ltd., KC-01B, was used.

(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 stirred for about 2 hours.
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 agitation at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. In addition, crystalline germanium dioxide was dissolved in water by heating, and ethylene glycol was added thereto, and a heat-treated catalyst solution and a phosphoric acid ethylene glycol solution were separately supplied continuously to the second esterification reactor. . This esterification reaction product is continuously
Feed into the polycondensation reactor and stir at about 265 ° C, 25 to
rr for 1 hour and then about 2 hours with stirring in a second polycondensation reactor.
The polycondensation was carried out at 65 ° C. and 3 torr for 1 hour and further with stirring in a final polycondensation reactor at about 275 ° C. and 0.5 to 1 torr for 1 hour. The melt polycondensation reaction product was cooled with cooling water (sodium content 0.01 ppm, magnesium content 0.02
ppm, the calcium content is 0.03 ppm, the silicon content is 0.07 ppm, and the particles having a particle size of 1 to 25 μm are 260 ppm.
(0 pieces / 10 ml), cut in a semi-solid state while cooling into chips, and transported to a storage tank by a plug transport method, and then fine and film-like substances are removed by a vibrating sieving process and an airflow classification process. Thus, the total content thereof was set to about 5 ppm or less (the highest peak temperature of the melting peak temperature of fine and the like was 255 ° C.), and then transported to a continuous solid-state polymerization apparatus. . Crystallization was performed at about 155 ° C. under a nitrogen atmosphere, and further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-state polymerization reactor to perform solid-state polymerization at about 207 ° C. under a nitrogen atmosphere.

A raw material chip supply port (1) at the upper part of the processing tank, an overflow discharge port (2) located at the upper limit level of the processing water in the processing tank, and a discharge of a mixture of the polyester chips and the processing water at the lower part of the processing tank. The treated water discharged from the outlet (3), the overflow outlet, and the treated water discharged from the drainage device (4) for the polyester chips discharged from the outlet at the lower part of the treatment tank are used as the filter medium. A pipe (6) sent again to the water treatment tank via a fine filtration / removal device (5), which is a continuous filter, and an adsorption tower (8), a GAF filter bag PE-1P2S made by ISP (polyester felt, Introduction of water obtained by introducing new ion-exchanged water from outside the system into the inlet (9) in the middle of the pipe (6) via a particle removing device in water and an ion exchanger with a filtration accuracy of 1 μm). With mouth (7) Tower type capacitive 50 m ^3, a polyethylene terephthalate using a processing tank shown in FIG. 1 - DOO (hereinafter,
(Abbreviated as PET) chips were continuously water-treated.

The above solid-state polymerized PET chips were processed by a vibrating sieving step and an airflow classification step to reduce the content of fines and film-like substances to about 10 ppm (the finest or the like having the highest melting peak temperature of the melting peak temperature). After the water temperature was 248 ° C.), the water was continuously charged from the supply port (1) at the upper part of the processing tank controlled to a processing water temperature of 95 ° C., and the water treatment time was 3 hours. PET from lower outlet (3)
Water treatment was performed while continuously extracting the chips together with the treated water. The content of particles having a particle size of 1 to 25 μm in the introduced water collected before the ion-exchanged water introduction port (9) of the treatment apparatus is about 1900 particles / 10 ml, and the sodium content is 0.01.
ppm, magnesium content 0.02ppm, calcium content 0.03ppm, silicon content 0.07p
pm, and the number of particles of recycled water having a particle size of 1 to 40 μm after treatment in the filtration device (5) and the adsorption tower (8) was about 18,000 / 10 ml. The cooling water used for chipping and the treated water used for the water treatment were industrial water (derived from underground river water) from GAF filter bag PE- manufactured by ISP.
Treated with 1P2S (polyester felt, filtration accuracy 1 μm) and ion exchanger

After the water treatment, the mixture was continuously dried with heated dry air, and subsequently treated in a vibrating sieving step and an airflow classification step to remove fines and film-like substances, so that the total content was about 11 ppm. . The melting peak of this fine etc.
The peak temperature on the highest side of the peak temperature was 248 ° C. A part of a SUS304 gravity transport pipe connected to a transport container filling step installed under the airflow classification step is provided with a linear low-density polyethylene (MFR = about 0.9 g / 10 min,
Density = about 0.923 g / cm ³⁾ made of ten rod-like body having a diameter of about 1cm in one step, the inner pipe fitted with a contact device with five arrangements, polyethylene to drop the PET chips removing fine etc. Contact treatment was performed. After this contact treatment, it was further treated in an airflow classification step.

The intrinsic viscosity of the obtained PET was 0.74 deciliter / gram, the content of DEG was 2.5 mol%, the content of the cyclic trimer was 0.30% by weight, and the increase in the cyclic trimer was 0. 0.04% by weight, average density of 1.4030 g / cm ³ ,
AA content is 2.3ppm, fine content is about 9pp
m, polyethylene content was about 15 ppb. The residual amount of Ge measured by fluorescent X-ray analysis was 47 pm, and the residual amount of P was 30 ppm.

The air for sending the solid-phase polymerized PET chips to the subsequent steps and the dehumidifying air for drying are J
An air purifier equipped with a filter unit made of PET non-woven fabric of type 3 of IS B 9908 (1991) and JIS
B 9908 (1991) Type 1 particle collection rate 99
% Of air filtered with an air purifier equipped with a HEPA filter unit of at least
0 / cubic feet).

The PET was evaluated using a molded plate and a biaxially stretched bottle. Table 1 shows the results. The haze of the molded plate is 3.9%, and the density of the plug portion is 1.371 g.
/ Cm ³ and is no problem value, also the transparency of the bottle 1.
0%, haze unevenness was 1.05, and thickness unevenness was 1.02, which was good. Also, there was no problem in the leakage test of the contents, and there was no deformation of the plug portion. AA content of bottle is 14.8
The value was no problem with ppm. 5,000 or more continuous stretch blow-molding was performed, but no mold contamination was observed.
The transparency of the bottle was also good.

(Example 2) PET was manufactured by the same equipment and in the same manufacturing method as in Example 1, except that the polyethylene rod in Example 1 was changed to nylon 6. The results are shown in Table 1. All the results were satisfactory. Example 3 The same equipment and the same manufacturing method as in Example 1 were adopted except that the rod made of polyethylene was replaced with a rod of almost the same size made of polybutylene terephthalate.
T was manufactured. The results are shown in Table 1. All the results were satisfactory.

(Comparative Example 1) After melt polycondensation, after solid phase polymerization,
Excluding the step of removing the fine and film-like substances after the water treatment and the PE contact treatment, the treatment is not performed, and the air sent to the drying step and the dehumidified air for drying are not treated by the air purifier. Produced PET in the same manner as in Example 1. The highest peak temperature of the melting peak temperature of fines and the like contained in the PET was 278 ° C. The melt-polymerized chips were extruded into the atmosphere, immediately cooled in cooling water, cut into completely cooled strands into chips, and sent to a storage tank by air transport. . P obtained
Table 1 shows the properties of the ET, the molded plate obtained by molding it, and the biaxially stretched bottle. The intrinsic viscosity of the obtained PET is 0.7
4 deciliters / gram, DEG content 2.5 mol%, cyclic trimer content 0.31 wt%, cyclic trimer increase 0.05 wt%, average density 1.4030 g /
cm ³ , the AA content was 2.3 ppm, and the fine content was about 650 ppm. The residual amount of Ge measured by fluorescent X-ray analysis was 47 pm, and the residual amount of P was 31 pp.
m. The haze of the formed plate was as high as 33.2%, and there was a problem that the haze was very uneven. In the leakage test of the contents, leakage of the contents was recognized. The barrel haze of the obtained bottle was 15.8%, and the haze unevenness was 1.
8. The thickness unevenness was extremely high at 1.5, which was problematic.

[0156]

[Table 1]

[0157]

According to the present invention, a transparent and / or film-like material is removed after the crystalline thermoplastic resin is blended into polyester by contact treatment with a member made of the crystalline thermoplastic resin. It is possible to form a hollow molded body having good properties, no unevenness of transparency and thickness unevenness, excellent heat resistance dimensional stability, and appropriate crystallization of the plug portion. In addition, mold contamination is reduced in sheet molding, bottle molding, and the like, and a large number of molded articles can be easily molded with excellent transparency for a long time. This is because, when performing contact treatment with a member made of a crystalline thermoplastic resin, the member is peeled off from the member, or fine particles or lump bodies of the crystalline thermoplastic resin that are missing are removed. This is because properties such as transparency are improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an example of a water treatment device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Raw material chip supply port 2 Overflow discharge port 3 Polyester chip and treated water discharge port 4 Drainage device 5 Fine removal device 6 Pipe 7 Recycle water or / and ion exchange water inlet 8 Adsorption tower 9 Ion Exchange water inlet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J029 AA03 AB04 AE01 AE03 AE18 BA03 BA05 CB06A JF361 KE02 KE03 KH05 KH08 KJ08

Claims (10)

[Claims] 1. A low-polymer production step (a) in which an aromatic dicarboxylic acid or a functional derivative thereof is esterified or transesterified with a glycol or a functional derivative thereof, and the low-polymer production step is obtained. A melt polycondensation step (b) of melt-polycondensing the low polymer, a water treatment step (c) of contacting the polyester obtained in the melt polycondensation step with water, and crystallizing the polyester obtained in the water treatment step. (D) a contact treatment with a member made of a thermoplastic resin, and a fine removal step (e) for removing fines and / or films from the polyester obtained in the contact treatment. Characteristic polyester production method. 2. A low polymer production step (a) in which an aromatic dicarboxylic acid or a functional derivative thereof is esterified or transesterified with a glycol or a functional derivative thereof, and the low polymer production step is carried out. A melt polycondensation step (b) for melt polycondensation of the low polymer, a solid phase polymerization step (f) for solid phase polymerization of the polyester obtained in the melt polycondensation step, and a polyester obtained in the solid phase polymerization step. A water treatment step (c) of contacting with water, a contact treatment step (d) of treating the polyester obtained in the water treatment step with a member made of a crystalline thermoplastic resin, and a polyester obtained in the contact treatment step A step of removing fines and / or a film-like substance from the product (e). 3. Fine and / or intermediate treatments between the melt polycondensation step (b) and the water treatment step (c) and / or between the water treatment step (c) and the contact treatment step (d).
2. The method for producing a polyester according to claim 1, wherein a step (g) of removing fines or the like for removing a film-like substance is added. 4. An intermediate step between the melt polycondensation step (b) and the solid state polymerization step (f), an intermediate step between the solid state polymerization step (f) and the water treatment step (c), or the water treatment step (c). ) And at least one of the intermediate steps of the contact treatment step (d), a step (g) for removing fines and / or film-like substances is added to the intermediate step. A method for producing the polyester as described above. 5. The polyester treated in the fine etc. removing step (e) has a content of any of fine content, film content, or total content of fine content and film content. The method for producing a polyester according to any one of claims 1 to 4, wherein the content is 300 ppm or less. 6. The polyester content, film content, or fine content of the polyester fed to the water treatment step (c), the contact treatment step (d) or the solid phase polymerization step (f). The method for producing a polyester according to any one of claims 1 to 5, wherein the content of any one of the total contents of the film-like substances is 300 ppm or less. 7. The highest peak temperature of the melting peak temperature of the fine and / or film-like substance contained in the polyester treated in the fine or the like removing step (e) is 265 ° C. or less. 7. The method according to claim 1, wherein
The method for producing a polyester according to any one of the above. 8. A method for melting fine and / or film-like substances contained in the polyester supplied to the water treatment step (c), the contact treatment step (d) or the solid phase polymerization step (f). The peak temperature on the highest side of the peak temperature is
The method for producing a polyester according to any one of claims 1 to 7, wherein the temperature is 265 ° C or lower. 9. The method according to claim 1, wherein the crystalline thermoplastic resin is at least one resin selected from the group consisting of a polyolefin resin, a polyamide resin, a polyacetal resin, and a polybutylene terephthalate resin. Items 1 to 8
The method for producing a polyester according to any one of the above. 10. The polyester having an intrinsic viscosity of 0.55 to 0.55.
The polyester production method according to any one of claims 1 to 9, wherein a main repeating unit of 1.30 deciliter / gram is a polyester composed of ethylene terephthalate.