JP2003012789A - Method for producing polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyester having excellent continuous moldability over a long period and giving a molded article, especially a heat-resistant hollow molded article having excellent transparency and dimensional stability with heat and small variation of crystallization rate. SOLUTION: The polyester is produced by contacting chips of a polyester containing ethylene terephthalate as a main recurring unit under flowing condition with at least one member selected from a member made of a polyolefin resin, a member made of a polyamide resin, a member made of a polyacetal resin and a member made of a polybutylene terephthalate resin. In the production process, the ratio A of the surface area (cm<2> ) of the member to the surface area (m<2> /hr) of the treated polyester chips per unit time satisfies the formula A=[surface area (cm<2> ) of the member]/[the surface area (m<2> /hr) of the polyester chips per unit time]=0.005-6.

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 preferably used as a raw material for molded products such as hollow molded products including beverage bottles, films and sheets, and more particularly to a transparent method. With excellent heat resistance and dimensional stability, with little fluctuation in crystallization rate
The present invention relates to a method for producing a polyester which gives a sheet-like product having excellent slipperiness and dimensional stability after molding. The present invention also relates to a method for producing a polyester which has good mold releasability from a heat treatment mold when molding a hollow molded article and has excellent long-term continuous moldability.

[0002]

2. Description of the Related Art Polyester (hereinafter sometimes abbreviated as PET) whose main repeating unit is ethylene terephthalate has excellent transparency, mechanical strength, heat resistance,
Depending on characteristics such as gas barrier properties, carbonated drinks, juices,
It is used as a material for containers such as mineral water, and its spread is remarkable. In these applications, polyester bottles are hot-filled with a beverage that has been sterilized at high temperature, or the beverage is sterilized at high temperature after filling, but with a normal polyester bottle, shrinkage occurs during such heat-filling treatment. Deformation occurs and becomes a problem. As a method for improving the heat resistance of a polyester bottle, a method has been proposed in which the bottle mouth plug is heat-treated to increase the crystallinity, or the stretched bottle is heat-fixed. In particular, when the crystallization of the spout is insufficient or the crystallization degree varies greatly, the sealing property with the cap may be deteriorated and the contents may leak.

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

In order to improve the heat resistance of the body of the bottle, for example, as shown in Japanese Patent Publication No. 59-6216, a method of heat treatment by increasing the temperature of the stretching blow mold is adopted. However, if a large number of bottles are molded using the same mold by such a method, the bottles obtained with long-term operation will be whitened and the transparency will be reduced, and only bottles with no commercial value can be obtained. . It was found that this was because deposits due to PET were attached to the mold surface, resulting in mold stains, which were transferred to the bottle surface. In particular, in recent years, the molding speed has been increased along with the downsizing of bottles, and from the viewpoint of productivity, shortening the heating time for crystallizing the spout and mold fouling have become more serious problems. .

Further, if PET is extruded into a sheet-like material and the molded article obtained by vacuum forming the same is filled with food and the lid made of the same material is left to stand, shrinkage occurs and the opening property of the lid is improved. If the molded body is left unattended for a long period of time, it contracts and the lid cannot be formed.

[0006]

Various proposals have been made to solve such problems. 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), an organic nucleating agent such as a montanic acid wax salt, etc. There is a method of adding (JP-A-57-125246 and JP-A-57-207639), but these methods have a problem in practical use due to the generation of foreign matters and clouding. Further, a method in which a treated polyester obtained by crushing a polyester molded product obtained by melt molding from the polyester is added to the raw material polyester (Japanese Patent Laid-Open No. 105807/1993).
However, this method requires an extra step of melt molding and pulverization, and there is a risk of inclusion of impurities other than polyester in such a post step, which is an economically and quality preferable method. is not. Further, a method of inserting a heat-resistant resin piece into the plug portion (Japanese Patent Laid-Open No. 61-259).
Japanese Patent Laid-Open No. 946 and Japanese Patent Laid-Open No. 2-269638) have been proposed, but the productivity of bottles is poor and there is a problem in recyclability.

A method for modifying PET by contacting a PET chip with a polyethylene member under flow conditions (Japanese Patent Laid-Open No. 9-71639), or a member made of polypropylene resin or polyamide resin under the same conditions. Method of modifying PET by contact with PET (JP-A-11-2
No. 09492) has been proposed, but it has been found that it is very difficult to obtain a stable crystallization rate and transparency even by such a method.

The present invention solves the problems of the above-mentioned conventional methods, and efficiently produces a molded product, particularly a heat-resistant hollow molded product, which is excellent in transparency and heat-resistant dimensional stability and has little fluctuation in crystallization rate. It is an object of the present invention to provide a method for producing a polyester which is excellent in continuous moldability for a long period of time and which does not stain the mold.

[0009]

In order to achieve the above object, the method for producing a polyester of the present invention comprises a polyester resin having a main repeating unit of ethylene terephthalate, a polyolefin resin member and a polyamide resin member. In the method for producing polyester, which comprises subjecting at least one member selected from the group consisting of a polyacetal resin member and a polybutylene terephthalate resin member to a contact treatment under flow conditions, the surface area of the member (c
m ² ) and the surface area (m ² / hour) of the polyester chip per unit time (A) are characterized in that the contact treatment is carried out so as to satisfy the following formula. A = [surface area of the member (cm ² ) / surface area of polyester chip per unit time (m ² / hour)] = 0.005 to 6

Here, the surface area of the member is the surface area of the member that may come into contact with the polyester chips under flowing conditions. For example, when the member is installed in the pipe of the transfer path of the chip, if a part of the surface of the member cannot contact the chip due to the installation method, the surface area thereof is not included in the calculation of A.

In this case, before the contact treatment and / or
Or the fine content of the polyester after the contact treatment,
Either the content of the film-like material or the total content of the fine content and the content of the film-like material is 30
It can be 0 ppm or less.

Here, fine means JIS-Z8801.
According to JIS-Z8801 means a fine polyester powder that has passed through a sieve with a mesh size of 1.7 mm, and a film-like material remains on a sieve with a mesh size of 5.6 mm according to JIS-Z8801. Of polyester, two or more chips are fused together, or the chip-shaped product cut into pieces larger than the normal shape is removed, and the thickness is about 0.5 mm.
The following film-like materials are meant, and their contents are measured by the following measuring methods.

In this case, before the contact treatment and / or
Alternatively, the peak temperature on the highest side of the melting peak temperature of the fine and / or film-like material contained in the polyester after the contact treatment may be 265 ° C or lower.

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 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 melting peaks,
The melting peak temperature of the highest temperature side of the
In the examples and the like, the "melting temperature of fine film" and the "melting point of film-like material" are referred to as the "melting temperature".

In this case, the polyester chip has a sodium content, a magnesium content, a silicon content and a calcium content in the cooling water which are N, M and S respectively in the chip forming step after the melt polycondensation. , C, chips can be formed using cooling water that satisfies at least one of the following (1) to (4). N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4) In this case, the contact The untreated polyester may be solid-state polymerized. In this case, when the polyester before the contact treatment was melted at a temperature of 290 ° C. for 60 minutes, the increase in cyclic trimer was 0.
It can be up to 50% by weight.

In this case, the polyolefin resin can be at least one resin selected from the group consisting of polyethylene resins and polypropylene resins.

By the above-mentioned method for producing a polyester of the present invention, it is possible to efficiently produce a molded product which is excellent in transparency and heat-resistant dimensional stability and has little fluctuation in crystallization rate.
It is possible to obtain polyesters whose main repeating unit is ethylene terephthalate.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing the polyester of the present invention will be described in detail below. The polyester according to the present invention is a polyester having ethylene terephthalate as a main repeating unit produced from terephthalic acid or its ester-forming derivative and ethylene glycol or its ester-forming derivative as raw materials, and preferably Is a linear polyester containing 85 mol% or more of ethylene terephthalate units, and more preferably 90 mol%.
The linear polyester containing 95% or more is particularly preferable.

As the dicarboxylic acid as a copolymerization component used when the polyester is a copolymer,
Aromatic dicarboxylic acids such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid and functional derivatives thereof, p-oxybenzoic acid, oxycaproic acid, etc. Oxyacids and their functional derivatives, adipic acid, sebacic acid, succinic acid, glutaric acid and other aliphatic dicarboxylic acids and their functional derivatives, cyclohexanedicarboxylic acid and other aliphatic dicarboxylic acids and their functional derivatives, etc. .

As the glycol used as a copolymerization component when the polyester is a copolymer, diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, etc. may be used. Aliphatic glycols, alicyclic glycols such as cyclohexane dimethanol, bisphenol A, aromatic glycols such as alkylene oxide adducts of bisphenol A and the like can be mentioned.

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

The above polyester can be produced by a conventionally known production method. That is, in the case of PET, direct esterification is carried out by directly reacting terephthalic acid with ethylene glycol and, if necessary, other copolymerization components to distill off water to effect esterification, and then polycondensate 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 distill off methyl alcohol for transesterification and then polycondensation under reduced pressure. .

Further, if necessary, the intrinsic viscosity is increased, and the low acetaldehyde content and the low cyclic trimer content such as the heat resistant container for low flavor beverages and the film for the inner surface of metal cans for beverages are used. Is required, the melt-polycondensed polyester thus obtained is solid-state polymerized.

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

An example of a preferable continuous production method will be described below using polyethylene terephthalate as an example. First, the case of producing a low polymer by an esterification reaction will be described. A slurry containing 1.02 to 1.5 mol, preferably 1.03 to 1.4 mol of ethylene glycol per 1 mol of terephthalic acid or its ester derivative was prepared, and this was subjected to an esterification reaction. Supply continuously to the process.

In the esterification reaction, water or alcohol produced by the reaction is rectified by using a multistage apparatus in which at least two esterification reactors are connected in series under the condition that ethylene glycol is refluxed. It is carried out while removing it outside the system in the tower. The temperature of the first stage esterification reaction is 240 to
270 ° C, preferably 245-265 ° C, pressure 0.2
~ 3 kg / cm ² G, preferably 0.5-2 kg / cm ²
G. The temperature of the last stage esterification reaction is usually 25
0 to 280 ° C., preferably 255 to 275 ° C., the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.
It is 3 kg / cm ² G. When it is carried out in three or more stages, the reaction conditions for the intermediate stage esterification reaction are
It is a condition between the reaction conditions of the first stage and the reaction conditions of the final stage. The increase in the reaction rate of these esterification reactions is preferably distributed smoothly at each stage. Finally, the esterification reaction rate is 90% or more, preferably 93%
It is desirable to reach the above. A low-order condensate having a molecular weight of about 500 to 5000 is obtained by these esterification reactions.

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

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

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 used with respect to 1 mol of dimethyl terephthalate. A solution containing benzene is prepared and continuously supplied to the transesterification reaction step.

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

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

The polycondensation reaction uses a polycondensation catalyst. A compound of Ge, Sb, Ti, or Al is used as the polycondensation catalyst, but it is also possible to use a mixed catalyst of Ge compound and Ti compound, Ge compound and Al compound, Sb compound and Ti compound, and Sb compound and Ge compound. It is convenient. These compounds are powder, aqueous solution, ethylene glycol solution,
It is added to the reaction system as a slurry of ethylene glycol or 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 dissolved in water by heating, or ethylene glycol added thereto and heat treated A solution or the like is used, and in particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water or a solution in which ethylene glycol is added and heated. In addition to these, compounds such as germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite may be mentioned. When using a Ge compound, the amount used is G in the polyester resin.
e Remaining amount of 10 to 150 ppm, preferably 13 to
It is 100 ppm, more preferably 15 to 70 ppm.

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

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

Further, as the Al compound, specifically,
Aluminum formate, aluminum acetate, basic aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum laurate, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate,
Carboxylates such as aluminum citrate and aluminum salicylate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, polyaluminum chloride,
Inorganic acid salts such as aluminum nitrate, aluminum sulfate, aluminum carbonate, aluminum phosphate, aluminum phosphonate, aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum iso-propoxide, aluminum n-butoxide, aluminum t-butoxide, etc. Aluminum chelate compounds such as aluminum alkoxide, aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum and other organoaluminum compounds and their partial hydrolysates. , Aluminum oxide and the like. Among these, carboxylates, inorganic acid salts and chelate compounds are preferable, and among these, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferable. The Al compound is added so that the amount of Al remaining in the produced polymer is in the range of 5 to 200 ppm.

In the method for producing polyester of the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination. Examples of alkali metals and alkaline earth metals include Li, Na, K, Rb, Cs, Be and M.
At least one selected from g, Ca, Sr, and Ba is preferable, and the use of an alkali metal or a compound thereof is more preferable. When using an alkali metal or a compound thereof, use of Li, Na and K is particularly preferable.
Examples of the alkali metal or alkaline earth metal compound include, for example, formic acid, acetic acid, propionic acid, butyric acid of these metals,
Saturated aliphatic carboxylates such as oxalic acid, unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid, aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, lactic acid, citric acid, Hydroxycarboxylic acid salts such as salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, hydrogen phosphate, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid, bromic acid, etc. Acid salts, organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid, organic sulfates such as laurylsulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert. -Alkoxides such as butoxy, chelate compounds with acetylacetonate, hydrides,
Examples thereof include oxides and hydroxides. The above-mentioned alkali metal compound or alkaline earth metal compound is added to the reaction system as a powder, an aqueous solution, an ethylene glycol solution or the like. Alkali metal compounds or alkaline earth metal compounds are used as the residual amount of these elements in the produced polymer in the range of 1 to
Add so that it is in the range of 50 ppm. The catalyst compound can be added at any stage of the polyester formation reaction step.

Various P compounds can be used as stabilizers. Examples of the P compound used in the present invention include phosphoric acid, phosphorous acid and their derivatives, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, phosphines. System compounds and the like. Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester,
Phosphoric acid dimethyl ester, phosphoric acid monobutyl ester,
Phosphoric acid dibutyl ester, phosphorous acid, phosphorous acid trimethyl ester, phosphorous acid triethyl ester, phosphorous acid tributyl ester, methylphosphonic acid dimethyl, methylphosphonic acid diphenyl, phenylphosphonic acid dimethyl,
Diethyl phenylphosphonate, diphenyl phenylphosphonate, dimethyl benzylphosphonate, diethyl benzylphosphonate, diphenylphosphinic acid, methyl diphenylphosphinate, phenyl diphenylphosphinate,
Phenylphosphinic acid, methyl phenylphosphinate,
Phenyl phenylphosphinate, diphenylphosphine oxide, methyldiphenylphosphine oxide,
Examples thereof include triphenylphosphine oxide, which may be used alone or in combination of two or more kinds. The P compound is 1 to 1 as the residual amount of P in the produced polymer.
It can be added at any stage of the above-mentioned polyester formation reaction step so that it is in the range of 1000 ppm.

Next, the above polyester is solid-phase polymerized by a conventionally known method in order to lower the acetaldehyde content, if necessary. First, the polyester to be subjected to solid-phase polymerization is pre-crystallized by heating at a temperature of 100 to 210 ° C. for 1 to 5 hours under an inert gas, a reduced pressure, or an atmosphere of steam or a steam-containing inert gas. It Then, solid phase polymerization is performed at a temperature of 190 to 230 ° C. for 1 to 30 hours in an inert gas atmosphere or under reduced pressure.

The polyester of which the main repeating unit is ethylene terephthalate according to the present invention has an intrinsic viscosity of 0.55 to 1.30 deciliter / gram, preferably 0.60 to 1.20 deciliter / gram, More preferably, it is in the range of 0.65 to 0.90 deciliter / gram. If the intrinsic viscosity is less than 0.55 deciliter / gram, the mechanical properties of the obtained molded product may be poor. On the other hand, when it exceeds 1.30 deciliters / gram, the resin temperature becomes high when melted by a molding machine or the like, and thermal decomposition becomes violent, resulting in an increase in free low-molecular-weight compounds that affect aroma retention, or a molded product. May be colored yellow.

The shape of the polyester chips may be any of cylinder type, square type, spherical type or flat plate type,
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
Is the range. For example, in the case of a cylinder type, it is practical that the length is 1.5 to 4 mm and the diameter is about 1.5 to 4 mm. In the case of spherical particles, the maximum particle size is 1.1 to 2.0 times the average particle size, and the minimum particle size is 0.
It is practical that it is 7 times or more. Moreover, the weight of the chip is practically in the range of 10 to 40 mg / piece.

When the sodium content, the magnesium content, the silicon content and the calcium content in the cooling water in the chipping step are N, M, S and C, respectively, the following (1) to It is preferable that the molten polycondensed polyester is chipped so as to satisfy at least one, and preferably all of (4). N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4)

When cooling water that deviates from the above conditions is used, these metal-containing compounds adhere to the surface of the polyester chip, the final polyester obtained has a very high crystallization rate, and its fluctuation is large. May occur, which is not preferable.

The acetaldehyde content of the polyester according to the present invention is 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 acetaldehyde content is 10 ppm or more and the formaldehyde content is 7 ppm or more, the flavor and odor of the contents such as a container molded from the polyester composition may be deteriorated. Although the lower limit of the content of acetaldehyde is preferably low, it is preferably 0.001 ppm or more from the viewpoint of economical production possibility.

The amount of diethylene glycol copolymerized in the polyester according to the present invention is 1.0 to 5.0 mol% of the glycol component constituting the polyester, preferably 1.3 to 4.5. Mol%, more preferably 1.5 to
It is 4.0 mol%. The amount of diethylene glycol is 5.0
If it exceeds mol%, the thermal stability tends to be poor, the molecular weight may be greatly reduced during molding, and the acetaldehyde content and the formaldehyde content may increase significantly, which is not preferable. If the content of diethylene glycol is less than 1.0 mol%, the transparency of the obtained molded product may deteriorate.

Further, the polyester cyclic 3 according to the present invention
Content of the monomer is 0.50% by weight or less, preferably 0.4
It is desirable to be 5% by weight or less, and more preferably 0.40% by weight or less. When molding a heat-resistant hollow molded article or the like from the polyester of the present invention, heat treatment is carried out in a heating mold, but when the content of the cyclic trimer is 0.50% by weight or more, the heating mold is The oligomer adhesion to the surface may be rapidly increased, and the transparency of the obtained hollow molded article may be extremely deteriorated. The lower limit of the content of the cyclic trimer is preferably 0.01% by weight or more from the viewpoint of economical production possibility.

Further, the polyester of which the main repeating unit before contact treatment is ethylene terephthalate according to the present invention is a step-formed plate (2 mm thick) obtained from this polyester when the temperature is raised. Crystallization temperature (hereinafter referred to as Tc1) is 155 ° C. or higher, preferably 16
It is preferably 0 ° C or higher.

In order to accelerate the crystallization rate of the molded product obtained from the above polyester and suppress its fluctuation, the polyester obtained by the melt polycondensation as described above, or the melt polycondensation and the subsequent solid phase polymerization. The polyester obtained by the above is at least one resin selected from the group consisting of a polyolefin resin member in a chip form, a polyamide resin member, a polyacetal resin member, and a polybutylene terephthalate resin member (hereinafter, "thermoplastic resin"). It may be abbreviated as "").

As a method for contacting the polyester with at least one resin member selected from the group consisting of a polyolefin resin member, a polyamide resin member, a polyacetal resin member, and a polybutylene terephthalate resin member, the thermoplastic resin is used. It is preferable to bring the polyester into collision contact with the member in the space where the resin member is present. Specifically, for example, immediately after melt polycondensation or solid phase polymerization of the polyester, or transportation of the polyester as a product. At the time of filling into the shipping container at the stage or discharging from the same container, at the time of introducing the molding machine at the molding step of polyester, etc. of the pneumatic transportation pipe, gravity transportation pipe, silo, magnet catcher A part of the magnet or the like is made of the thermoplastic resin, or the thermoplastic resin Toka lining, or rod-like body into said transfer path, the plate-like body, by, for example placing the thermoplastic resin member such as tubular member or mesh-like body, and a method of transferring the polyester. The contact time of the polyester with the member is usually about 0.01 second to a few minutes, but by such contact treatment, the above-mentioned polyolefin resin, polyamide resin, polyacetal resin or polybutylene is added to the polyester. A small amount of terephthalate resin can be blended.

In the method for producing polyester of the present invention, a polyester chip whose main repeating unit is ethylene terephthalate is prepared from a polyolefin resin member, a polyamide resin member, a polyacetal resin member, and a polybutylene terephthalate resin member. In the method for producing a polyester, which is subjected to a contact treatment with at least one member selected from the group under flowing conditions, the ratio of the surface area (cm ² ) of the member and the surface area (m ² / hour) of the polyester chip per unit time A is a method for producing polyester, which is characterized in that contact treatment is carried out so as to satisfy the following formula. A = [surface area of the member (cm ² ) / surface area of polyester chip per unit time (m ² / hour)] = 0.005 to 6

The surface area (cm ² ) of the member and the surface area (m) of the polyester chip contact-treated per unit time
The ratio A of ( ² / h) is preferably 0.007 or more, more preferably 0.008 or more, preferably 5.5 or less, and more preferably 5 or less. When the ratio A of the surface area (cm ² ) of the member and the surface area (m ² / hour) of the polyester chip per unit time is less than 0.005,
The blending amount of the thermoplastic resin in the polyester becomes small, and thus the crystallization rate of the obtained molded article may be insufficient and the variation thereof may be large. In addition, crystallization of the plug portion of the hollow molded body becomes insufficient, and the shrinkage amount of the plug portion does not fall within the specified value range, so that a capping phenomenon may occur. The surface area of the member (c
When the ratio A of m ² ) to the surface area (m ² / hour) of the polyester chip per unit time exceeds 6, the blending amount of the thermoplastic resin in the polyester becomes excessive and the blending amount fluctuates extremely. Can become large. As a result, the crystallization rate of the obtained molded product may be high, or the fluctuation may be very large. Then, the crystallization of the plug part of the hollow molded body becomes excessive, so that the shrinkage amount of the plug part does not fall within the specified value range, the capping of the plug part becomes defective, and the leakage of the contents occurs. The preform for use may be whitened, which makes normal stretching impossible.

Here, the surface area (m ² / hour) of the polyester chip per unit time means the surface area (m ² / hour) of the polyester chip that is contact-treated with the member made of the thermoplastic resin per unit time. That is.

The shape of the polyester chip is determined to be cylindrical, elliptic, spherical, flat plate-like or the like depending on the model of the chip cutter, the shape of the extrusion die of the polyester melt, and the like. However, the chip shape may not exactly match any of the above shapes. In such a case, the shape of the chip is visually observed and it is determined that the chip corresponds to any one of the above shapes.
Therefore, in the present invention, the average chip size corresponding to the thus determined chip shape is measured by the following method, and then, per chip based on the formula for determining the surface area corresponding to the shape. Average surface area S (c
m ² ) is calculated.

That is, the average chip size is not measured by measuring abnormal shapes such as fine particles, crushed pieces, and 2 to several fused materials, and a caliper is used for 50 chips according to the chip shape. (For example, in the case of a nearly spherical body, the diameter, and in the case of an elliptic cylinder, the minor axis, major axis, length, etc.)
Is measured and the average value is calculated for each.

The average weight per chip (mg
/ Piece) is the total of 50 chips whose chip size is measured.
The weight is calculated and the average value is calculated. And in the present invention
Surface area of polyester chips per unit time
(M ²/ Hour) is calculated by the following formula
It Surface area of polyester chip per unit time (m²/
Hour) = Q × S × 10^Five/ W (Where Q = unit made of the thermoplastic resin and unit time
Weight of chips to be contact-processed per interval (ton / hour) S = average surface area of one chip (cm²/Individual) W = average weight of one chip (mg / piece) Is. )

Examples of the polyolefin resin used in the present invention include polyethylene resin, polypropylene resin, and α-olefin resin. Further, these resins may be crystalline or amorphous.

The polyethylene resin used in the present invention includes, for example, ethylene homopolymer, ethylene, and propylene, butene-1,3-methylbutene-.
1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, decene-1 and other α-olefins having about 2 to 20 carbon atoms, vinyl acetate, vinyl chloride,
Examples thereof include acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, styrene, and copolymers with vinyl compounds such as unsaturated epoxy compounds. Specifically, for example, ultra-low / low / medium / high-density polyethylene (branched or linear) ethylene homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene- 4-methylpentene-1 copolymer, ethylene-
Hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, etc. An ethylene resin can be used.

Examples of the polypropylene resin used in the present invention include propylene homopolymer, propylene, ethylene, butene-1,3-methylbutene-1, pentene-1,4-methylpentene-1,
2 carbon atoms such as hexene-1, octene-1, decene-1
To about 20 other α-olefins, copolymers with vinyl compounds such as vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, styrene, hexadiene, octadiene,
Examples thereof include copolymers with diene such as decadiene and dicyclopentadiene. Specific examples include propylene-based resins such as propylene homopolymers (atactic, isotactic, syndiotactic polypropylene), propylene-ethylene copolymers, propylene-ethylene-butene-1 copolymers.

As the α-olefin resin used in the present invention, homopolymers of α-olefins having about 2 to 8 carbon atoms, such as 4-methylpentene-1, and those α-olefins, ethylene and propylene. , Butene-
1,3-methylbutene-1, pentene-1, hexene-
Examples thereof include 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 resin such as butene-1 homopolymer, 4-methylpentene-1 homopolymer, butene-1-ethylene copolymer, butene-1-propylene copolymer and 4 -A copolymer of methylpentene-1 and a C2-C18 α-olefin, and the like.

The polyamide resin used in the present invention is, for example, butyrolactam, δ-valerolactam, ε-caprolactam, enanthlactam, ω.
Polymers of lactams such as laurolactam, polymers of aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 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) A cycloaliphatic diamine such as cyclohexylmethane), a diamine unit such as aromatic diamine such as m- or p-xylylenediamine, and an aliphatic dicarboxylic acid such as glutaric acid, adipic acid, suberic acid and sebacic acid, cyclohexanedicarboxylic acid Alicyclic dicarboxylic acid, 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. Further, these resins may be crystalline or amorphous.

Examples of the polyacetal resin used in the present invention include polyacetal homopolymers and copolymers. As the polyacetal homopolymer, the density measured by the measuring method of ASTM-D792 is 1.40 to 1.42 g / cm ³ , and ASTM D-12.
Melt flow ratio (MFR) measured at a temperature of 190 ° C. and a load of 2160 g by the measuring method of 38 is 0.5 to 50 g / 10.
Polyacetals in the minutes range are preferred. Further, as the polyacetal copolymer, the density measured by the measuring method of ASTM-D792 is 1.38 to 1.43 g / cm ³ ,
The melt flow ratio (MFR) measured by the method of ASTM D-1238 measured at 190 ° C. and a load of 2160 g is 0.
Polyacetal copolymers in the range of 4 to 50 g / 10 min are preferred. Examples of these copolymerization components include ethylene oxide and cyclic ethers.

As the polybutylene terephthalate resin used in the present invention, for example, a polybutylene terephthalate homopolymer consisting of terephthalic acid and 1,4-butanediol and naphthalene dicarboxylic acid,
Examples thereof include copolymers obtained by copolymerizing diethylene glycol, 1,4-cyclohexane dimethanol and the like.

The blending ratio of the thermoplastic resin used in the present invention to the polyester is preferably 0.
1 ppb or more, more preferably 0.3 ppb or more, further preferably 0.5 ppb or more, particularly preferably 0.5
ppb or more, preferably 1000 ppm or less, more preferably 100 ppm or less, further preferably 1 p
pm or less, particularly preferably 45 pbb or less.

When the compounding amount is less than 0.1 ppb, the crystallization rate becomes very slow, and the mouth plug portion of the hollow molded article may be insufficiently crystallized. The shrinkage of the part does not fall within the specified value range, resulting in poor capping. Also, the stretch heat-fixing mold for molding the heat-resistant hollow molding is heavily contaminated, and it often occurs when trying to obtain a transparent hollow molding. You may have to clean the mold. If it exceeds 1000 ppm, the crystallization speed will be high and the crystallization of the plug part of the hollow molded article will be excessive, and the shrinkage / shrinkage amount of the plug part will not fall within the specified range, resulting in poor capping. In some cases, leakage of material may occur, or the preform for a hollow molded body may be whitened, which makes normal stretching impossible. Further, 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 with large thickness unevenness and poor transparency is obtained. It may not be possible.

When the above-mentioned member made of thermoplastic resin is contact-treated with polyester, it is desirable that the thermoplastic resin exists in a state of being adhered to the surface of the polyester chip, but the polyester chip collides with the member. In the state where the thermoplastic resin member does not adhere to the polyester chip, depending on the magnitude of the impact force at the time of contact or the pressure force at the time of contact, or the properties such as impact resistance and peeling resistance of the thermoplastic resin member, That is, there is also one in which the polyester chips are mixed with the above-mentioned contact-treated polyester chips independently of the polyester chips. The molded product obtained from the polyester in such a mixed state may have an excessively high crystallization rate or may have a very large fluctuation in the rate.

In the case of a preformed body for a hollow molded body, the whitening and the unevenness of transparency are severe, and normal stretching is impossible,
In some cases, only a hollow molded article having large thickness unevenness and poor transparency may be obtained. Usually, the above contact-treated polyester is present as fine fine particles, but sometimes in the form of granules or agglomerates having an average particle diameter of about 0.5 to several mm, independent of the polyester chips. It may be mixed in. In such a case, the thermoplastic resin becomes a foreign substance in the obtained molded product, and as a result, the resulting molded product may have many defects such as uneven thickness, voids, and whitening. is there. Therefore, it is desirable to remove the fine particles, particles or lumps of the thermoplastic resin that exist independently of the polyester chips before molding.

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

The melt-polycondensed polyester is chipped and then transported to a silo or the like in a transport pipe for storage, or transported to the next step such as a solid phase polymerization step or a water treatment step. Similarly, solid-state polymerized polyester chips are also transported to the next step or silo. When such chips are transported by, for example, a forced low-density transportation method using air, a large impact force is applied to the surface of the polyester chips due to a collision with a pipe, and as a result, fines or film-like substances are generated. It occurs in large quantities. Most of the fines and the film-like material produced in this way are 2
It has a very high melting peak temperature of over 65 ° C. Also, when solid phase polymerization is carried out using a rotary type solid phase polymerization apparatus, or when a feeder for applying impact force or shearing force to the polyester chip is used as a transportation method to the next step, Melting peak above 265 ° C
Fine temperature and film-like material are generated. this is,
It is presumed that the chip may generate heat due to a large force such as an impact force applied to the chip surface, and at the same time, oriented crystallization of polyester may occur on the chip surface, resulting in a dense crystal structure.

The fine or film-like material of polyester having a melting peak temperature above 265 ° C. is melted by subjecting it to solid-state polymerization treatment with polyester chips or water treatment. Pee
The temperature is higher than before treatment. Also, the melting peak is 265 ° C or lower, but much higher than the normal melting peak temperature.
Fines and film-like substances having a peak temperature also have a melting peak temperature exceeding 265 ° C. by the above-mentioned treatments. It is presumed that this is because the crystal structure is changed to a more dense crystal structure by these treatments.

265 ° C. higher than the normal melting point
When a polyester containing a fine or film-like substance having a melting point peak of more than 100 is molded under normal molding conditions, the crystals do not completely melt during melt molding and remain as crystal nuclei.
As a result, the crystallization rate at the time of heating becomes faster, and the crystallization of the plug part of the hollow molding container becomes excessive, and the shrinkage amount of the plug part does not fall within the specified value range, and the capping of the plug part occurs. There may be a problem that the product becomes defective and the contents leak. In addition, the preform for blow molding may be whitened, and thus normal stretching may not be possible, resulting in uneven thickness, or the transparency of the obtained hollow mold may be deteriorated due to high crystallization speed. In some cases, there may be large fluctuations in transparency.

When it is desired to obtain a preform for blow molding or a sheet having good transparency and stretchability from polyester containing fines having a melting peak temperature exceeding 265 ° C, the temperature is 300 ° C. It must be melt-molded at the above high temperature. However, at such a high temperature of 300 ° C. or higher, thermal decomposition of the polyester becomes severe, and a large amount of by-products such as acetaldehyde and formaldehyde are generated,
As a result, the flavor and the like of the obtained molded product or the like will be greatly affected. Further, when the polyester obtained by the production method of the present invention contains the thermoplastic resin as described above, the thermoplastic resin is often inferior in thermal stability to the polyester of the present invention, and therefore, as described above, 300 In the case of molding at a high temperature of ℃ or higher, a large amount of by-products are generated by thermal decomposition, so that the flavor of the obtained molded product or the like may have a greater effect.

Polyester generally contains about 1 to about 1000 ppm of the fines including the fines and film-like substances described above, depending on the production method, and such fines are uniformly mixed in the polyester chips. Not ubiquitous, but ubiquitous. Therefore,
When such a polyester is subjected to a contact treatment with a member made of the thermoplastic resin under flowing conditions, the crystallization rate is further increased, but only polyester having a very fluctuating rate can be obtained, which may be a problem. .

Further, in the present invention, the fine content of the polyester before the contact treatment with the member and / or after the contact treatment, the film-like content, or the total content of the fine content and the film-like content. Either content is 300 ppm or less, preferably 200 ppm or less,
More preferably, the above problems can be solved by lowering it to 100 ppm or less.

Either the fine content of the polyester before the contact treatment with the member and / or after the contact treatment, the content of the film-like material, or the total content of the fine content and the content of the film-like material. When the value exceeds 300 ppm, the crystallization rate of the molded product from the obtained polyester at the time of heating becomes high, and the crystallization of the plug part of the hollow molding container becomes excessive, so that the shrinkage amount of the plug part is regulated. The value may not fall within the range, capping of the spout may become defective, and the content may leak. In addition, the preform for blow molding may be whitened, and thus normal stretching may not be possible, resulting in uneven thickness, or the transparency of the obtained hollow mold may be deteriorated due to high crystallization speed. There are also cases where there are large fluctuations in transparency.

The present invention also relates to the peak temperature on the highest side of the melting peak temperature of the fine and / or film-like substance contained in the polyester before and / or after the contact treatment with the member. However, when the temperature is 265 ° C. or lower, the above problems are further solved.

Examples of the method for separating and removing the fine and / or film-like substances from the polyester before and / or after the contact treatment with the member include the following methods. That is, in the case of the melt polycondensed polyester, there is a method of treating the polyester in a vibrating sieving step, an air stream classification step by an air flow, or the like immediately before or after the contact treatment with the member made of the thermoplastic resin. Further, in the case of solid phase polymerized polyester, immediately before the solid phase polymerization step and the vibrating sieving step and the air flow classification step by an air flow which are separately installed immediately before and after the step of contact-treating with the member made of the thermoplastic resin, And the like.

As a method for preventing the inclusion of fine and / or film-like substances whose melting peak temperature on the highest side of the melting peak temperature exceeds 265 ° C., after the contact treatment with the thermoplastic resin, The method of processing in the fines removal step as described above can be mentioned.

By using the polyester obtained by the above-mentioned production method, a molded article having excellent transparency and little fluctuation in the crystallization rate can be obtained, but for the above-mentioned reason, a molded article made of the thermoplastic resin is used. It is also necessary to pay attention to the content of the fine or film-like substances contained in the polyester before the contact treatment and their properties.

A concrete example of a method for preventing the polyester before the contact treatment with the thermoplastic resin from containing such fines having a high melting point will be described below. In the case of melt polycondensed polyester, chips are formed by a method of extruding molten polyester into water from a die after melt polycondensation and cutting in water, or a method of immediately extruding into the air and then cutting while cooling with cooling water,
Then, after draining the polyester chips formed into chips, chips or fine or film-like substances of a shape other than a predetermined size are removed by a vibration sieving process and an airflow classification process by an air flow, or a water washing process process, and a plug transportation method or Bucket type conveyor-Sending to storage tank by transportation method.

The chips are taken out of the tank with a screw.
It is transported to the next process by a plug feeder or a bucket type conveyor transport system by a formula feeder, and fine removal treatment is performed immediately before or after the contact treatment process by an air flow classification process by an air flow. Further, in the case of solid-phase polymerized polyester, the melt polycondensed polyester which has been subjected to the removal treatment of the fine or film-like material is again subjected to an air flow classification step by an air stream immediately before the solid-state polymerization step to obtain the fine or film-like material. It is removed and put into a solid phase polymerization step. When transporting the melt-polycondensed prepolymer chips to the solid-state polymerization equipment or sieving the polyester chips after the solid-state polymerization,
When transporting to the contact treatment step or a storage tank, most of these transports adopt the plug transport system or the bucket type conveyor transport system, and the chips are not extracted from the crystallization device or the solid-state polymerization reactor. By using a screw feeder, etc., use a device that can minimize the impact between the chip and the process equipment, transportation piping, etc.

As a gas for contacting the polyester after the melt polycondensation step or the solid phase polymerization step, or the polyester after the contact treatment with the member made of the thermoplastic resin, particles having a particle size of 0.3 to 5 μm are 1,000,000 ( Individual/
Cubic sheet) or less, preferably 500000 (pieces /
Cubic feet) or less, more preferably 100,000
It is desirable to use the gas below (individual / cubic feet) introduced from outside the system. Particles in the gas having a particle size of more than 5 μm are not particularly limited, but preferably 5
(Pieces / cubic feet) or less, more preferably 1 (pieces / cubic foot)
Cubic feet) or less.

In the polyester production process, a container such as a silo, a hopper of a molding machine, a transport container, etc. is passed through each step such as a melt polycondensation step, a solid-state polymerization step, etc., such as a sieving step and an air stream classification step. In order to transport and dry the polyester during these steps, air around the treatment equipment is generally taken into the steps by a blower or the like and used. Conventionally, such air is either left untreated or used according to JIS B 9908 (199).
It was generally used only after being treated by a cleaner equipped with a low-performance filter unit such as type 3 defined in 1). However, the polyester treated in such a process may cause a problem that only a molded product having poor transparency can be obtained. In particular, before and after the contact treatment step with the member made of the thermoplastic resin,
If air of the above quality is used as the gas that comes into contact with the polyester, the crystallization rate, transparency, etc. of the obtained molded product will vary greatly, which is likely to cause a problem.

Therefore, in the method for producing polyester by contact treatment with a member made of the thermoplastic resin of the present invention, after melt polycondensation, after solid phase polymerization, after water treatment or with a member made of the thermoplastic resin. Among the polyesters after the contact treatment, at least one polyester has a particle size of 0.3 to 5 μm as a gas to be contacted in any one of the transporting step to the next step, the sieving step, the storing step, and the container filling step. It is desirable to use a gas having particles of 1,000,000 (pieces / cubic foot) or less, which is introduced from outside the system.

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

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

Particle size 0.3 to 5 in gas introduced from outside the system
As a method of reducing the number of particles of μm to 1,000,000 (pieces / cubic feet) or less, cleaning by removing the particles at least at one or more places during the process until the gas introduced from the outside comes into contact with the polyester chips Install the device. In the case where the gas is air in the vicinity of the treatment facility, JIS B 9908 (19) is used during the process in which the air introduced by the blower from the air inlet comes into contact with the polyester chips.
91), a gas purifying apparatus equipped with a type 1 or / and type 2 filter unit is installed, and the number of particles having a particle size of 0.3 to 5 μm in the air is 1,000,000 (pieces / cubic foot). The following is preferred. In addition, by installing a gas cleaning device equipped with a filter unit of type 3 defined in JIS B 9908 (1991) at the air inlet and using the gas cleaning device equipped with the filter unit described above, It is possible to extend the life of the filter unit.

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

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

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

Furthermore, in the present invention, the polyester before the contact treatment with the member made of the thermoplastic resin is 2
A polyester in which the amount of cyclic trimer increase when melted at a temperature of 90 ° C. for 60 minutes is 0.50% by weight or less, more preferably 0.30% by weight or less, still more preferably 0.10% by weight or less.

The polyester whose amount of increase of cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is 0.30% by weight or less is a polycondensation catalyst for polyester obtained after melt polycondensation or after solid phase polymerization. It can be manufactured by deactivating. Examples of the method for deactivating the polyester polycondensation catalyst include a method in which the polyester chips are subjected to contact treatment with water, steam, or a steam-containing gas after melt polycondensation or after solid-phase polymerization.

A method for treating the above polyester chips with water, steam or a gas containing steam will be described below.
Examples of the hot water treatment method include a method of immersing in hot water and a method of spraying water on the chips with a shower. The treatment time is 5 minutes to 2 days, preferably 10 minutes to 1 day, more preferably 30 minutes to 10 hours, and the water temperature is 2 minutes.
The temperature is 0 to 180 ° C, preferably 40 to 150 ° C, more preferably 50 to 120 ° C.

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

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

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 defined as X and sodium. When the content is N, the content of magnesium is M, the content of calcium is C, and the content of silicon is S, at least one, preferably all of the following (5) to (9) is satisfied, and water is obtained. It is desirable to perform processing. 1 ≤ X ≤ 50,000 (pieces / 10 ml) (5) 0.001 ≤ N ≤ 1.0 (ppm) (6) 0.001 ≤ M ≤ 0.5 (ppm) (7) 0.001 ≤ C ≤ 0 .5 (ppm) (8) 0.01 ≤ S ≤ 2.0 (ppm) (9)

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

Particle sizes of 1 to 25 μm used for water treatment below
The method for obtaining water containing 1 to 50000 particles / 10 ml of the above is exemplified. As a method for reducing the number of particles in water to 50,000 / 10 ml or less, an apparatus for removing particles is installed at least at one or more steps in the process of supplying natural water such as industrial water to a treatment tank. Preferably from the natural water sampling port, to the treatment tank described above, a pipe for returning the water drained from the treatment tank to the treatment tank again, a fine removal device, and the like, to a treatment device including incidental equipment necessary for water treatment A device for removing particles is installed between them, and the particle size of 1
The content of particles of ˜25 μm is 1 to 50,000 / 10 m
It is preferable that it is 1. Examples of the device for removing particles include a filter-filtration device, a membrane filtration device, a settling tank, a centrifuge, and a foam entrainment processor. For example filter
If it is a filtering device, the method is a belt filter method,
Examples of the filter device include a bag filter system, a cartridge filter system, a screen filter system, and a centrifugal filtration system. Among them, the belt filter is for continuous operation.
A system, a centrifugal filtration system, a bag filter system, and a screen filter system are suitable. Further, in the case of a belt filter type filtering device, examples of the filter material include paper, metal, cloth and the like. In addition, the size of the mesh of the filter should be 5 to improve the efficiency of particle removal and treated water flow.
The thickness is 100 μm, preferably 10 to 70 μm, and more preferably 15 to 40 μm.

In order to reduce the amount of sodium, magnesium, calcium, and silicon in the water from outside the system to the above range, sodium, magnesium, calcium, A device for removing silicon is installed. In addition, a filter is installed to remove clay minerals such as silicon dioxide and aluminosilicate which are in the form of particles. Examples of the device for removing sodium, magnesium, calcium, and silicon include an ion exchange device and an ultrafiltration device.

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 treated as industrial wastewater, a large amount of new water can be used. Not only that, but there is concern that the increase in the amount of wastewater will have an impact on the environment. That is, by returning at least a part of the treated water discharged from the treatment tank to the water treatment tank and reusing it, it is possible to reduce the necessary amount of water, and it is possible to reduce the effect on the environment due to the increase in the amount of drainage. If the wastewater returned to the water treatment tank maintains a certain temperature,
Since the heating amount of the treated water can be reduced, it is preferable that the treated water discharged from the treated layer be returned to the water treated layer and reused. In addition, by reusing water, the flow rate of treated water in the treated layer can be increased, and as a result, fines attached to the polyester chips can be washed away,
Fine removal effect is also created. Here, as the treated water that is discharged from the water treatment tank and then returned to the treatment tank and reused, the water discharged from the overflow port of the water treatment tank and the polyester chips from the treatment tank are used together. There is treated water that has been drained and then separated from the chips.

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

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

Fines and fine particles contained in the treated water adhere to the polyester chip, and thereafter, fines and fine particles adhere to or permeate the polyester chip in the step of drying and removing water. Since the content is very large, the polyester obtained in this way has a high crystallization rate, so the transparency of the obtained bottle is poor, and the crystallinity at the time of crystallization of the bottle cap is excessive. As a result, the dimensions of the spigot part do not meet the standard, which may cause capping failure of the spigot part and leakage of the contents.

Therefore, in the present invention, after being discharged from the water treatment tank, at least a part of it is returned to the treatment tank to be reused so that the particle size existing in the treated water is 1 to 40 μm.
100,000 particles / 10 ml or less, preferably 80,000 particles / 10 ml or less, more preferably 500
It is desirable to keep the number of cells per 100 pieces / 10 ml or less. Here, the treated water thus returned to the treatment tank and reused is referred to as recycled water.

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

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

When the polyester chips are contacted with steam or a steam-containing gas to process, 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 as steam in an amount of 0.5 g or more per 1 kg of granular polyethylene terephthalate. The granular polyethylene terephthalate is contacted with steam. The contact between the polyester chips and steam is usually 10 minutes to 2 days, preferably 20 minutes to 10 days.
Done on time.

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

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

In the case where the polyester chips are continuously contacted with steam, granular tower terephthalate is continuously received from the upper part in a tower-type processing apparatus, and steam is continuously supplied in cocurrent or countercurrent to contact steam. Can be processed. As described above, when treated with water or steam, the granular polyethylene terephthalate is drained by a draining device such as a vibrating screener or a simon carter, and if necessary, transferred to the next drying step.

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

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

The polyester obtained by the production method of the present invention has a thickness of 2 mm obtained by melt-molding the polyester.
Crystallization temperature (Tc1) of the test piece from the molded body
Is in the range of 150 to 168 ° C., preferably 155 to 165
It is preferably in the range of ° C. When Tc1 exceeds 168 ° C., the heating crystallization rate becomes very slow, and the effect of improving crystallization may not be expected in some cases. Also, Tc1 is 1
If the temperature is lower than 50 ° C., the transparency of the hollow molded article may decrease, which may cause a problem.

The polyester used in the present invention may optionally contain other additives such as known ultraviolet absorbers,
Antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from the outside or lubricants deposited internally during the reaction, release agents, nucleating agents,
You may mix | blend various additives, such as a stabilizer, an antistatic agent, and a pigment. The polyester obtained by the above-mentioned production method of the present invention is injection-molded and stretch-blow-molded into a stretched hollow molded article, and extrusion-molded into a sheet-like material.

[0114]

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

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

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

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

(4) Acetaldehyde content of polyester (hereinafter referred to as “AA content”) Sample / distilled water = 1 g / 2 cc A nitrogen-substituted glass ampoule was sealed with the upper part and subjected to extraction at 160 ° C. for 2 hours. After treatment and cooling, acetaldehyde in the extract was measured by high sensitivity gas chromatography and the concentration was expressed in ppm. The chip was used as it was as a resin sample, and in the case of a bottle, the resin cut out from the body was cut into about 3 mm square and used.

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

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

(7) Melting point measurement of fine and film-like substances Differential scanning calorimeter (DS) manufactured by Seiko Denshi Kogyo KK
C), measured using RDC-220. In (6),
The fine or film-like material collected from 20 kg of polyester was dried under reduced pressure at 25 ° C. for 3 days, and then DSC measurement was performed at a temperature rising 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 calculated. The measurement is performed on a maximum of 10 samples, and the average value of the melting peak temperatures on the highest temperature side is obtained.

(8) Average Density of Polyester Chip, Density of Preform Mouth Portion The density was measured at 30 ° C. with a density gradient tube of a calcium nitrate / water mixed solution. Further, the density of the plug portion was calculated as an average value of 10 samples crystallized by the method (11), and the density deviation of the plug portion was calculated from the value of 10 samples.

(9) Haze (% haze) and haze unevenness Samples were cut from the body (wall thickness 5 mm) of the following (13) and the body (wall thickness approximately 0.45 mm) of the hollow molded body of (14). , Nippon Denshoku Co., Ltd. haze meter, model NDH
Measured at 2000. In addition, a forming plate formed 10 times in succession
The haze (wall thickness: 5 mm) was measured, and the haze unevenness was determined by the following. Haze spot = maximum haze value / minimum haze value

(10) Crystallization temperature (T
c1) Differential thermal analyzer (DS
C), measured with RDC-220. Using 10 mg of a sample from the center of a 2 mm-thick plate of the following (13) shaped plate. The temperature is raised at a temperature rising rate of 20 ° C./minute, and the peak temperature of the crystallization peak observed during the heating is measured and used as the crystallization temperature during heating (Tc1).

(11) Density increase due to heating of preform plug part The preform plug part was heat treated for 90 seconds by a home-made infrared heater, and a sample was taken from the top surface to measure the density.

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

(13) Molding of Stepped Molded Plate A dried polyester was manufactured by Meiki Seisakusho M-150C (D
M) A stepped flat plate mold (surface temperature of about 2 ° C) cooled with water at 10 ° C at a cylinder temperature of 290 ° C by an injection molding machine.
2 ° C.) for molding. The obtained step forming plate is 2,
A plate having a thickness of 3, 4, 5, 6, 7, 8, 9, 10, and 11 mm and a size of about 3 cm × about 5 cm square was provided stepwise, and the weight of one piece was about 146 g. A plate having a thickness of 2 mm is used for measuring Tc1 and a plate having a thickness of 5 mm is used for measuring haze (% haze).

(14) Molding of Hollow Molded Body Polyester was dried by a dryer using dehumidified air, and a preform was molded at a resin temperature of 290 ° C. by an M-150C (DM) injection molding machine manufactured by each machine manufacturer. . This prefor
The mouth plug part of the glass was heated and crystallized by a home-made mouth part crystallizer. Next, this preform was biaxially stretched and blown at a ratio of about 2.5 times in the longitudinal direction and about 3.8 times in the circumferential direction with an LB-01E molding machine manufactured by COPOPLAST Co., and subsequently about 150 times.
Heat set for about 7 seconds in the mold set to ℃, and the capacity is 200
A 0 cc container (body thickness 0.45 mm) was molded. The stretching temperature was controlled to 100 ° C.

(15) Leakage Evaluation of Contents from Hollow Molded Body The hollow molded body molded in (14) above was filled with hot water at 90 ° C., capped with a capping machine, and then the container was laid down and left to stand. I investigated the leak. In addition, the state of deformation of the spout after capping was also examined.

(16) Cooling water in the chipping step and sodium content, calcium content, magnesium content and silicon content in the introduced water of the water treatment step The particle-removed and ion-exchanged cooling water or introduced water was collected. After filtering with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., the filtrate was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation. (17) Measurement of the number of particles in the introduced water and the recycled water during water treatment Particle removal of the introduced water that has undergone particle removal and ion exchange, or the recycled water that has been treated with the filtration device (5) and the adsorption tower (8), using the light blocking method. The number of particles was measured using a PAC 150 manufactured by Seishin Enterprise Co., Ltd.
Displayed in ml.

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

Example 1 A slurry of high-purity terephthalic acid and ethyl glycol was continuously supplied to a first esterification reactor containing a reactant in advance, and the slurry was stirred to about 2
The reaction was carried out at 50 ° C. and 0.5 kg / cm ² G for an average residence time of 3 hours. This reaction product was sent to the second esterification reactor, and reacted under stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. Further, crystalline germanium dioxide was heated and dissolved in water, ethylene glycol was added thereto, and a heat-treated catalyst solution and ethylene glycol solution of phosphoric acid were separately fed continuously to the second esterification reactor. . This esterification reaction product is continuously fed to the first
It is supplied to the polycondensation reactor and stirred at about 265 ° C at 25 to
rr for 1 hour, then in a second polycondensation reactor under stirring for about 2
65 ° C., 3 torr for 1 hour, and further with stirring in the final polycondensation reactor at about 275 ° C., 0.5-1 torr for about 1.5.
It was polycondensed for an hour. The obtained melt polycondensed PET had an intrinsic viscosity of 0.75 deciliter / gram and a cyclic trimer content of 1.03% by weight.

The melt polycondensation reaction product was cooled with cooling water (sodium content 0.01 ppm, magnesium content 0.02).
While cooling at ppm, calcium content 0.04 ppm, silicon content 0.06 ppm), an elliptic column-shaped chip (minor axis = 0.2 cm, major axis = 0.35 cm, length =
0.4 cm) into chips and then transported to a storage tank, and then fine and film-like substances are removed by a vibrating sieving process and an air stream classifying process to reduce the total content of these to about 10 ppm or less. SU connected to the container filling process for transportation installed after the airflow classification process
A linear low-density polyethylene (MI = about 0.9 g / 10 min, density = about 0.926) was attached to a part of the transportation pipe made of S304.
The inside of the transportation pipe connected to a cylindrical pipe made of g / cm ³ ) having an inner diameter of 70 mm and a length of 700 mm was transported at about 3 tons / hour for contact treatment.

[0134] The ratio A of the surface area per chip by calculation is 0.464Cm ^2, also polyester chips surface area per unit time (m ² / hr) surface area of the cylindrical pipe to (cm ²⁾ is It was about 0.35. After the contact treatment, it was further treated in the airflow classification step. The content of fines etc. contained in PET after treatment is about 15p
The peak temperature on the highest side of the melting peak temperature of pm was 265 ° C or lower. The PET was evaluated using a molded plate and a biaxially stretched molded bottle. The stepped plate (5 mm thickness) has a haze of 5.0% and Tc1 of 16
2 ° C, the density of the plug part of the hollow molded body is 1.371 g / cm
It is a value that is ³ and there is no problem, the transparency of the bottle is 1.2%,
The haze unevenness was 1.06, and the thickness unevenness was 1.03. (Example 2) A slurry of high-purity terephthalic acid and ethyl glycol was continuously fed to a first esterification reactor containing a reactant in advance, and the mixture was stirred at about 250 ° C at a temperature of 0.
The reaction was carried out at 5 kg / cm ² G for an average residence time of 3 hours.
The reaction product was sent to the second esterification reactor and stirred,
The reaction was carried out at a temperature of about 260 ° C. and 0.05 kg / cm ² to a predetermined degree of reactivity. Further, crystalline germanium dioxide was heated and dissolved in water, ethylene glycol was added thereto, and a heat-treated catalyst solution and ethylene glycol solution of phosphoric acid were separately fed continuously to the second esterification reactor. . This esterification reaction product is continuously fed to the first polycondensation reactor and stirred at about 265 ° C. and 25 torr for 1 hour.
Then, under stirring in the second polycondensation reactor, at about 265 ° C., 3 to
rr for 1 hour, then with stirring in the final polycondensation reactor for about 2
Polycondensation was carried out at 75 ° C. and 0.5 to 1 torr for 1 hour. The molten polycondensation reaction product is cooled with cooling water (sodium content of 0.01
ppm, magnesium content 0.02 ppm, calcium content 0.04 ppm, silicon content 0.08 p
After chipping while cooling at pm), the chips are transported to a storage tank, and then fine and film-like substances are removed by a vibrating sieving step and an air stream classifying step to reduce the total content of these to about 5 ppm or less, Then, it was transported to a continuous solid-state polymerization apparatus. Crystallize at about 155 ° C in a nitrogen atmosphere, and after preheating to about 200 ° C in a nitrogen atmosphere,
It was sent to a continuous solid-state polymerization reactor and solid-state polymerized at about 207 ° C. under a nitrogen atmosphere.

[0135] The raw material chip supply port (1) at the upper part of the processing tank, the overflow discharge port (2) located at the upper limit level of the treated water in the processing tank, and the discharge of the mixture of polyester chips and the treated water at the lower part of the processing tank. The treated water discharged from the outlet (3) and the overflow flow outlet and the treated water that passed through the polyester chip drainer (4) discharged from the outlet at the lower part of the treatment tank have a filter medium of paper. Piping (6) sent again to the water treatment tank via the fine filtration removal device (5) which is a continuous filter and the adsorption tower (8), GAF filter bag PE-1P2S (polyester felt, manufactured by ISP) Introducing water obtained by introducing new ion-exchanged water from outside the system into the inlet (9) in the middle of this pipe (6) via a device for removing particles 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 treated with water. The solid-state polymerized PET chips were processed by a vibrating sieving process and an airflow classifying process to obtain a fine and film-like substance content of about 13 ppm (the peak temperature of the highest melting peak temperature such as fine). Was 246 ° C.), and then continuously charged from the upper supply port (1) of the treatment tank controlled to a treated water temperature of 95 ° C. Water treatment was performed while continuously extracting PET chips together with treated water from the outlet (3). The content of particles having a particle size of 1 to 25 μm in the introduced water collected before the ion-exchanged water introducing port (9) of the above-mentioned treatment device is about 1800/10 m.
1, sodium content 0.01ppm, magnesium content 0.03ppm, calcium content 0.04
ppm, the silicon content is 0.08 ppm, and the number of particles of the recycled water after treatment in the filtration device (5) and the adsorption tower (8) is about 16000 particles / 10 m.
It was l.

After the water treatment, the product was continuously dried with heated dry air, and subsequently treated in a vibrating sieving process and an airflow classifying process to remove fines and film-like substances, and the total content thereof was adjusted to about 13 ppm. . This fine melting point
The peak temperature on the highest temperature side was 246 ° C. In addition, the minor axis of the tip = 0.15 cm, the major axis = 0.3
It was 5 cm and length = 0.35 cm. SUS3 to connect to the transportation container filling process installed after the airflow classification process
A linear low density polyethylene (MI = about 0.9 g / 10 minutes, density = about 0.926 g /
cm ³ ), the inner diameter of which is 70 mm, and the length of which is 300 mm. After the contact treatment, it was further treated in the airflow classification step.

The obtained PET had an intrinsic viscosity of 0.76 deciliter / gram, a DEG content of 2.7 mol%, a cyclic trimer content of 0.30% by weight, and a cyclic trimer increase amount of 0. 0.04% by weight, average density 1.430 g / cm ³ ,
AA content is 2.3ppm, fines content is about 12
The ppm and the polyethylene content were about 12 ppb.
In addition, as the air for sending the PET chips subjected to the solid-state polymerization to the subsequent steps and the dehumidified air for drying, JIS B 9
908 (1991) type 3 PET non-woven filter unit equipped with an air cleaner and JIS B 990
HE of 8 (1991) type 1 particle collection rate 99% or more
Air filtered by an air cleaner equipped with a PA filter unit (the number of particles having a particle size of 0.3 to 5 μm is 530 / cubic foot) was used. The PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. The haze of the molded plate is 4.1%, Tc1 is 165 ° C.,
The density of the spout was 1.370 g / cm ^3, which was a problem-free value, the transparency of the bottle was 1.0%, and the haze unevenness was 1.0.
4, the thickness variation was as good as 1.02. In addition, in the leak test of the contents, there was no problem and the mouth plug was not deformed.
The AA content of the bottle was 14.0 ppm, which was a value with no problem. After continuous stretching blow molding of 5000 or more bottles, no mold stain was observed and the transparency of the bottle was good.

(Example 3) Water treatment obtained in Example 2
The PET after drying is processed by a vibrating sieving process and an airflow classifying process to remove fines and film-like substances, and then PE
The contact treatment with PE pipe and the removal treatment such as fines were performed by the same equipment and method as in Example 2 except that only the length of the pipe was changed. However, the PE pipe for contact treatment had an inner diameter of 70 mm, a length of 3 m, and a treatment amount (ton / hour) of polyester per unit time during treatment of about 1 ton / hour. The results are shown in Table 1. There was no problem with the haze of the molded plate, the haze of the bottle, the haze unevenness, the thickness unevenness, and the result of the leakage test of the contents. After continuous stretching blow molding of 5000 or more bottles, no mold stain was observed and the transparency of the bottle was good.

Example 4 The PET obtained after the solid phase polymerization obtained in Example 2 was treated by a vibrating sieving step and an air stream classifying step to remove fines and film-like substances, and then water treatment was not performed. In a part of the gravity transportation pipe made of SUS304 that is connected to the transportation container filling process installed under the air flow classification process,
Linear low density polyethylene (MI = about 0.9 g / 10
Min, density = about 0.926 g / cm ³ ) made diameter about 1 c
The contact treatment was performed by dropping the inside of a vertical pipe connected with a contact device having 20 rod-shaped bodies each having a length of m and a length of about 30 cm attached at a treatment rate (ton / hour) per unit time of about 1 ton / hour. After this contact treatment, it was further treated in the airflow classification step.
The results are shown in Table 1, and all the results were satisfactory.

(Comparative Example 1) The size of a PET chip having an elliptic cylindrical shape was such that the minor axis of the chip was 0.15 cm and the major axis was 0.25.
cm, length = 0.25 cm, the polyethylene rod for contact treatment was changed to a polyethylene rod with a diameter of about 1 cm and a length of 5 cm, and the treatment amount of PET chips per unit time during contact ( PET was produced in the same manner as in Example 4 except that (ton / hour) was changed to about 8 ton / hour. The peak temperature on the highest temperature side of the melting peak temperature of the fine particles contained in this PET was 281 ° C. Table 1 shows the characteristics of the obtained PET, the molded plate obtained by molding the PET, and the biaxially stretch-molded bottle. There was a problem with the haze of the molded plate and the transparency of the bottle, the crystallization rate of the spout was slow, and leakage of the content was found in the leakage test of the content.

(Comparative Example 2) The size of an elliptic cylinder PET chip was as follows: minor axis = 0.2 cm, major axis = 0.25 c.
m, length = 0.3 cm, the length of the polyethylene pipe for contact treatment was 3 m, and the treatment amount of PET per unit time (ton / hour) was about 0.4 ton / hour. Manufactured PET in the same manner as in Example 3. Obtained P
Table 1 shows the properties of ET, a molded plate obtained by molding the same, and a biaxially stretch-molded bottle. The haze of the molded plate was very high, and the haze unevenness was very problematic. In addition, leakage of the contents was found in the leakage test of the contents. The haze, haze unevenness, and thickness unevenness of the obtained bottle were very high and had problems.

(Comparative Example 3) P was carried out in the same manner as in Example 2 except that the fine and film-like substance removing step and the water treating step after melt polycondensation, after solid phase polymerization and after contact treatment were omitted.
ET was manufactured. Table 1 shows the characteristics of the obtained PET, the molded plate obtained by molding the PET, and the biaxially stretch-molded bottle. This was a problem because the molded plate had a very high 44.9% and had haze unevenness. In addition, leakage of the contents was found in the leakage test of the contents. The body haze of the obtained bottle is 2
It had a problem of 4.2%, haze unevenness of 3.4, and thickness unevenness of 1.6, which were very high.

[0143]

[Table 1]

[0144]

INDUSTRIAL APPLICABILITY In the production method of the present invention, when the contact treatment is performed with at least one member selected from the group consisting of a polyolefin resin member, a polyamide resin member, a polyacetal resin member and a polybutylene terephthalate resin member. Since the ratio A of the surface area (cm ² ) of the member to the surface area (m ² / hour) of the polyester chip per unit time is kept within the above range, the transparency and the thickness unevenness are excellent. It is possible to mold a hollow molded article having no heat resistance, excellent dimensional stability in heat resistance, and proper crystallization of the plug portion. In addition, in sheet molding, bottle molding, etc., mold stains are reduced, and a large number of molded articles can be easily molded for a long time in a state of excellent transparency. This is because the amount of the thermoplastic resin adhered to the polyester chips is in the proper range and the variation in the amount of the adhered resin is small, so that the properties such as transparency of the obtained molded product are improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a water treatment device used in an example.

[Explanation of symbols]

1 Raw Material Chip Supply Port 2 Overflow Discharge Port 3 Polyester Chip and Treated Water Discharge Port 4 Drainer 5 Fine Removal Device 6 Piping 7 Recycled Water or / and Ion Exchange Water Inlet 8 Adsorption Tower 9 Ions Exchange water inlet

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshitaka Eto             20 No. 248 Takashiro, Shiga Town, Shiga District, Shiga Prefecture F-term (reference) 4J029 AA03 AC01 AC02 AE01 BA03                       BA10 BB13A BD03A BF13                       CA04 CA05 CA06 CB05A                       CB06A CB10A CC06A CF14                       EA02 EB04A HA01 HB01                       LB05

Claims (7)

[Claims] 1. A polyester chip whose main repeating unit is ethylene terephthalate is at least selected from the group consisting of a polyolefin resin member, a polyamide resin member, a polyacetal resin member, and a polybutylene terephthalate resin member. In the method for producing a polyester which is subjected to a contact treatment with a kind of member under flowing conditions, the ratio A of the surface area (cm ² ) of the member and the surface area (m ² / hour) of the polyester chip per unit time is expressed by the following formula. A method for producing a polyester, which comprises subjecting the material to contact treatment in a satisfactory manner. A = [surface area of the member (cm ² ) / surface area of polyester chip per unit time (m ² / hour)] = 0.005 to 6 2. The content of either the fine content of the polyester before the contact treatment and / or after the contact treatment, the content of the film-like material, or the total content of the fine content and the content of the film-like material, , 300 ppm or less, The method for producing a polyester according to claim 1, wherein 3. The peak temperature on the highest side of the melting peak temperature of the fine and / or film-like material contained in the polyester before and / or after the contact treatment is 265 ° C. or less. It exists, The manufacturing method of the polyester in any one of Claim 1 or 2 characterized by the above-mentioned. 4. The polyester chip has a sodium content, a magnesium content, a silicon content and a calcium content in cooling water, which are N, M, S and C, respectively, in a chip forming step after melt polycondensation. In this case, the chips are made by using cooling water that satisfies at least one of the following (1) to (4).
The method for producing a polyester according to any one of 1. N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4) 5. The method for producing a polyester according to claim 1, wherein the polyester before the contact treatment is solid-phase polymerized. 6. The polyester before the contact treatment is characterized in that the amount of cyclic trimer increase when the polyester is melted at a temperature of 290 ° C. for 60 minutes is 0.50% by weight or less. 5. The method for producing a polyester according to any one of 5 above. 7. The polyolefin resin is at least one resin selected from the group consisting of polyethylene resins and polypropylene resins.
7. The method for producing the polyester according to any one of 6 to 6.