JP2003171457A - Method for producing polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyester capable of providing a blow molded product excellent in transparency and scarcely containing a foreign matter. <P>SOLUTION: This method for producing the polyester comprises carrying out contact treatment of chips of a solid phase polymerization polyester in which a main recurring unit is ethylene terephthalate with a member composed of at least one kind of resin selected from a group consisting of a polyolefin resin, a polyamide resin and a polyacetal resin under fluid conditions. In the production method, a ratio of intrinsic viscosity (IVs) of the surface layer part of the polyester to intrinsic viscosity (IV) of the chip is 1.10 to 1.30 and a ratio of intrinsic viscosity (IVc) of the chip center part to the intrinsic viscosity (IV) of the chip is 0.90 to 0.98. <P>COPYRIGHT: (C)2003,JPO

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 used for packaging materials such as bottles and films, sheets and the like, and more specifically, it is a hollow molding which contains almost no foreign matter and is excellent in transparency. The present invention relates to a method for producing a polyester which gives a body or the like and is less likely to cause mold stains when the molded body is molded.

[0002]

BACKGROUND OF THE INVENTION Polyester is excellent in mechanical strength, heat resistance, transparency and gas barrier property, so that it is especially used for filling beverages such as juices, soft drinks, carbonated drinks, packaging films and audio. It is most suitable as a material for video films and is used in large quantities.

It is also used in large quantities on a global scale as an industrial material such as clothing fibers and tire cords.
In polyester bottles for beverages, hot sterilized beverages are hot-filled into the bottles, or they are sterilized at high temperature after filling the beverages, but in normal polyester bottles, shrinkage occurs during such heat-filling treatment. Deformation occurs and becomes a problem. As a method to improve the heat resistance of polyester bottles, heat treatment of the bottle mouth part to increase the crystallinity,
Further, a method of heat-fixing a stretched bottle has been proposed. 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.

Specifically, in the case of beverages requiring hot filling such as fruit juices, oolong tea and mineral water, the preform or the bottle cap portion of the molded bottle is heat treated. Then, a method of crystallization (see, for example, Patent Documents 1 and 2) 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.

Further, in order to improve the heat resistance of the bottle body, a method of heat treatment by increasing the temperature of the stretching blow mold is adopted (for example, see Patent Document 3). 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, as the size of bottles has been reduced, the molding speed has been increased, and from the viewpoint of productivity, shortening of the heating time for crystallizing the plug portion and mold fouling have become more serious problems.

[0006] Further, PET is extruded into a sheet-like material, and a molded product obtained by vacuum-forming this is filled with food and then covered with a lid made of the same material and left to stand, which causes shrinkage to cause the opening property of the lid. If the molded body is left unattended for a long period of time, it contracts and the lid cannot be formed.

[0007]

[Patent Document 1] JP-A-55-79237

[Patent Document 2] Japanese Patent Laid-Open No. 58-110221

[Patent Document 3] Japanese Patent Publication No. 59-6216

[0008]

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 pulverizing a polyester molded body obtained by melt molding from the above polyester is added to the raw material polyester (JP-A-5-10580).
No. 7), 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 economically and quality preferable. Not the way. Also, a method of inserting a heat-resistant resin piece into the plug portion (JP-A-61-25)
Japanese Patent No. 9946 and Japanese Patent Application Laid-Open No. 2-269638) have been proposed, but the productivity of bottles is poor and there is a problem in recyclability.

A method of modifying PET by contacting a PET chip with a polyethylene member under flowing 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
However, it has been found that it is very difficult to obtain a polyester having a moderate and stable crystallization rate and giving a molded article excellent in transparency even by such a method. It was

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

[0011]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that at least one solid phase polymerized polyester whose main repeating unit is ethylene terephthalate is selected from the group consisting of a polyolefin resin, a polyamide resin and a polyacetal resin. As a result of studying the production of a molded article which is excellent in transparency and heat-resistant dimensional stability and has little fluctuation in crystallization rate, using the polyester that has been contact-treated with a member made of the resin under flowing conditions, the solid-state polymerized polyester chip Of the intrinsic viscosity (IV) of the surface layer and the intrinsic viscosity (IV) of the chip, and the ratio of the intrinsic viscosity (IVc) of the solid core of the solid-state polymerized polyester to the intrinsic viscosity (IV) of the chip are related to these characteristics. And completed the present invention. That is, in the method for producing a polyester of the present invention, a chip of a solid-phase polymerized polyester whose main repeating unit is ethylene terephthalate is at least one selected from the group consisting of a polyolefin resin, a polyamide resin, and a polyacetal resin. A method for producing a polyester, which comprises subjecting a member made of a resin to a contact treatment under flowing conditions, wherein the ratio of the intrinsic viscosity (IVs) of the polyester chip surface layer portion to the intrinsic viscosity (IV) of the chip is 1.10 to 1. 30 and the ratio of the intrinsic viscosity (IVc) of the polyester chip center portion to the intrinsic viscosity (IV) of the chip is 0.
The method for producing polyester is characterized in that it is 90 to 0.97.

The ratio of the intrinsic viscosity (IVs) of the surface layer of the chip to the intrinsic viscosity (IV) of the chip and the ratio of the intrinsic viscosity (IVc) of the central part of the chip to the intrinsic viscosity (IV) of the chip are preferably respectively 1.12 to 1.28 and 0.91 to 0.96, and more preferably 1.15 to 1.23 and 0.92 to 0.95, respectively.

The ratio of the intrinsic viscosity (IVs) of the surface layer of the chip to the intrinsic viscosity (IV) of the chip exceeds 1.30, and the intrinsic viscosity (IVc) of the central part of the chip and the intrinsic viscosity of the chip (I
When the ratio V) is less than 0.90, the crystallization speed of the molded product obtained from this polyester during heating is increased, and the crystallization of the plug portion of the hollow molded container becomes excessive, which causes Since the amount of shrinkage of the stopper does not fall within the specified range, capping of the stopper will be defective and the contents will leak, and the preform for hollow molding will be whitened, which makes normal stretching impossible. .

The ratio of the intrinsic viscosity (IVs) of the surface layer of the chip to the intrinsic viscosity (IV) of the chip is less than 1.10, and the ratio of the intrinsic viscosity (IVc) of the central part of the chip to the intrinsic viscosity (IV) of the chip. When a solid-phase polymerized polyester having a particle size of more than 0.97 is produced, solid-state polymerization is carried out using a melt-polycondensed polyester of fine particles having an average particle size of 1.0 mm or less, or it takes a long time at a low temperature of 195 ° C or less. Therefore, it is necessary to carry out solid phase polymerization, which makes economical production of polyester difficult.

Thus, according to the method for producing a polyester of the present invention, a solid-phase-polymerized polyester which is excellent in transparency and heat-resistant dimensional stability and can produce efficiently a molded product having a small fluctuation in crystallization rate, particularly a heat-resistant hollow molded product. Can be obtained.

The limiting viscosity (IVs) of the surface layer of the chip
The intrinsic viscosity (IVc) of the center of the chip and the chip is measured by the following method.

In this case, either the fine content of the polyester before the contact treatment and / or the content of the polyester 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 is contained. Quantity
It is preferably 300 ppm or less.

Here, fine means JIS-Z88.
No. 01 means a fine polyester powder that has passed through a sieve with a nominal size of 1.7 mm and a film-like material remains on a sieve with a nominal size of 5.6 mm according to JIS-Z8801. Among polyesters, it means the film-like material after removing the chip-like material in which two or more chips are fused or cut into pieces larger than the normal shape. The content of these is measured by the following measuring method. To do.

In this case, the peak temperature on the highest temperature side of the melting peak temperature of fine contained in the polyester before and / or after the contact treatment is 265 ° C. or lower. Is preferred.

Here, as described below, the melting point of fine and the like is measured by a differential scanning calorimeter (DSC).
The melting peak temperature of DSC is called the melting point. The melting peak representing this melting point is composed of one or more melting peaks, and in the present invention, the melting peak is 1 or more.
In one case, the peak temperature, and in the case of a plurality of melting peaks, the highest melting peak temperature among the plurality of melting peaks is defined as "Fine melting peak". The peak temperature on the highest side of the peak temperature is referred to as "fine melting point" in Examples and the like.

Further, in this case, the polyester has a sodium content (N), a magnesium content (M), a silicon content (S) and a calcium content in a chip forming step after melt polycondensation. It is preferable that the amount (C) is polyester chipped with cooling water satisfying 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)

Further, in this case, it is preferable that the polyester before the contact treatment with the above-mentioned member has a cyclic trimer increase amount of 0.50% by weight or less when melted at a temperature of 290 ° C. for 60 minutes. .

Further, in this case, the member is composed of a pipe for pneumatic transportation of polyester chips, a pipe for gravity transportation of polyester chips, and a rod-like, plate-like or net-like body installed in a transfer route of polyester chips. It is preferably at least one selected.

[0024]

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

The dicarboxylic acid as a copolymerization component used when the polyester is a copolymer is
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. .

When the polyester is a copolymer, the glycol used as a copolymerization component includes diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol and the like. 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 esterify, and then perform polycondensation under reduced pressure. Law,
Alternatively, it is produced by a transesterification method in which dimethyl terephthalate is reacted with ethylene glycol and, if necessary, other copolymerization components to distill off methyl alcohol for transesterification and then polycondensation under reduced pressure. . The melt-polycondensed polyester thus obtained is then solid-state polymerized.

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

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. Also, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, quaternary ammonium hydroxide such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide and trimethylbenzylammonium hydroxide, and lithium carbonate. , A basic compound such as sodium carbonate, potassium carbonate, and sodium acetate was added in a small amount, the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate was reduced to a relatively low level (total It is preferable because it can be maintained at 5 mol% or less with respect to the 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 subjected to rectification 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.

As the starting materials dimethyl terephthalate, terephthalic acid or ethylene glycol, virgin dimethyl terephthalate derived from paraxylene, terephthalic acid or ethylene glycol derived from ethylene can be used as well as used PE.
A recovered raw material such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered from a T bottle by a chemical recycling method such as methanol decomposition or ethylene glycol decomposition can also be used as at least a part of the starting material. It goes without saying that the quality of the recovered raw material must be refined to the purity and quality according to the purpose of use.

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 is carried out using a polycondensation catalyst.
As the polycondensation catalyst, a compound of Ge, Sb, Ti, or Al is used, and Ge compound and Ti compound, Ge
It is also convenient to use mixed catalysts of compounds and Al compounds, Sb and Ti compounds, Sb and Ge compounds. These compounds are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries, and the like.

As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or a slurry of ethylene glycol, a solution of crystalline germanium dioxide dissolved in water by heating, or ethylene glycol added thereto and heat-treated. Although a solution or the like is used, in particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is heated and dissolved 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 amount of Sb remaining in the produced polymer is in the range of 50 to 250 ppm.

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. The alkali metal compound or the alkaline earth metal compound is added so that the residual amount of these elements in the produced polymer is in the range of 1 to 50 ppm.

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. Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, methylphosphonic acid,
Methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, and the like, which may be used alone or in combination of two or more. You may use together. 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.

The melt polycondensed polyester obtained as described above is extruded from the pores after completion of the melt polycondensation, and is made into chips while being cooled with cooling water. A melt polycondensed polyester prepolymer having an intrinsic viscosity of 0.50 to 0.75 deciliters / gram and a ratio of terminal carboxyl groups to all terminal groups of 15% or less obtained by the above-mentioned method is used under an inert gas atmosphere or under reduced pressure. Below 190-210
Solid phase polymerization is carried out so that the increase in intrinsic viscosity during solid phase polymerization is less than 0.20 deciliters / gram at a temperature of ℃
The polyester according to the present invention can be obtained by the following.

The polyester of which the main repeating unit is ethylene terephthalate according to the present invention has an intrinsic viscosity of 0.65 to 0.90 deciliter / gram, preferably 0.67 to 0.88 deciliter / gram, More preferably, it is in the range of 0.70 to 0.85 deciliter / gram. When the intrinsic viscosity of the polyester is less than 0.65 deciliter / gram, the mechanical properties of the obtained molded product are poor. Also, the intrinsic viscosity of polyester is 0.90.
If the amount exceeds deciliters / gram, the resin temperature rises during melting by a molding machine or the like, resulting in severe thermal decomposition, increasing the amount of free low-molecular-weight compounds that affect aroma retention and coloring the molded product in yellow. Problems such as occur.

The shape of the polyester chip of which the main repeating unit is ethylene terephthalate according to the present invention may be any of cylinder type, square type, spherical type or flat plate type, and the average grain size thereof. Diameter is usually 1.5-5
mm, preferably 1.6 to 4.5 mm, more preferably 1.8 to 4.0 mm. For example, in the case of a cylinder type, the length is 1.5 to 4 mm and the diameter is 1.5 to 4
It is practical that it is about mm. For spherical particles,
It is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. Further, it is practical that the weight of the chip is in the range of 10 to 30 mg / piece.

The acetaldehyde content of the polyester having ethylene terephthalate as the main repeating unit according to the present invention is 10 ppm or less, preferably 8 p.
pm or less, more preferably 5 ppm or less, formaldehyde content is 7 ppm or less, preferably 6 ppm or less,
More preferably, it is 4 ppm or less. If the acetaldehyde content exceeds 10 ppm or the formaldehyde content exceeds 7 ppm, the flavor and odor of the contents such as molded articles obtained from such polyesters deteriorate.

Further, the amount of diethylene glycol copolymerized with the polyester whose main repeating unit is ethylene terephthalate 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 4.0 mol%. If the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability will deteriorate,
It is not preferable because the molecular weight is greatly reduced during molding, and the acetaldehyde content and the formaldehyde content are greatly increased. If the content of diethylene glycol is less than 1.0 mol%, the transparency of the obtained molded product will be poor.

The content of the cyclic trimer of polyester according to the present invention whose main repeating unit is ethylene terephthalate is 0.5% by weight or less, preferably 0.45% by weight or less. Preferably 0.40% by weight
It is the following. When a heat-resistant hollow molded article or the like is molded from the polyester of the present invention, heat treatment is performed in a heating mold,
When the content of the cyclic trimer is 0.5% by weight or more, the oligomer adhesion to the surface of the heating die rapidly increases,
The transparency of the obtained hollow molded article is extremely deteriorated.

In the method for producing polyester of the present invention, the solid-phase-polymerized polyester chips are contact-treated with a member made of a resin such as a polyolefin resin under flowing conditions. As a method of contact-treating polyester with a resin member such as a polyolefin resin, it is preferable to bring the polyester into collision contact with the member in a space where the resin member is present. Specifically, for example, polyester Immediately after the solid-state polymerization of the above, or when the polyester is shipped as a product in a shipping container during filling or discharging, or when a polyester molding machine is loaded into the molding machine. Pipe, gravity transportation pipe, silo, a part of the magnet part of the magnet catcher is made of the resin, or the resin is lined, or a rod-shaped body, a plate-shaped body in the transfer path, A method of transferring polyester by, for example, installing the resin member such as a tubular body or a net body is mentioned. The contact time of the polyester with the member is usually a short time of about 0.01 second to several minutes, but the resin can be added to the polyester in a small amount.

In the method for producing a polyester of the present invention, chips of solid-phase polymerized polyester whose main repeating unit is ethylene terephthalate are at least selected from the group consisting of polyolefin resin, polyamide resin and polyacetal resin. The surface area (cm ² ) of the member and the throughput of the polyester chip per unit time (ton /
It is more preferable that the ratio A of ()) satisfies the following formula. A = surface area (cm ² ) of the member to be contact-treated with polyester / treatment amount of polyester chips per unit time (ton / hour) = 6 to 5000

The ratio A of the surface area (cm ² ) of the member to the throughput (ton / hour) of the polyester chip per unit time is preferably 8 to 4000, more preferably 1
It is 0 to 3000. When the ratio A of the surface area (cm ² ) of the member to the throughput (ton / hour) of the polyester chip per unit time is less than 6, the compounding amount of the resin in the polyester is small, and therefore The rate of crystallization of the obtained molded body is insufficient, and its fluctuation becomes large. Then, crystallization of the plug portion of the hollow molded body becomes insufficient, and thus the shrinkage amount of the plug portion does not fall within the specified value range, so that a capping phenomenon occurs. When the ratio A of the surface area (cm ² ) of the member to the throughput (tons / hour) of the polyester chip per unit time exceeds 5000, the amount of the resin blended into the polyester becomes excessive and The fluctuation of the quantity becomes very large. For this reason, the crystallization rate of the obtained molded body becomes fast, and the fluctuation thereof becomes very large. Then, the crystallization of the plug part of the hollow molded body becomes excessive, and the shrinkage amount of the plug part does not fall within the specified value range. The preform for use is whitened, which makes normal stretching impossible.

Examples of the resin used for the contact treatment in the present invention include at least one resin selected from the group consisting of polyolefin resin, polyamide resin and polyacetal resin. Examples of the polyolefin resin used for the contact treatment 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 is, for example, a homopolymer of ethylene, 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.

The α-olefin resin used in the present invention includes 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 - methylpentene-1 and C ₂ -C ₁₈ copolymer of α- olefins, and the like.

Examples of the polyamide resin used in the present invention include butyrolactam, δ-valerolactam, ε-caprolactam, enantolactam, 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 method of ASTM-D792 is 1.
38 to 1.43 g / cm ³ , a polyacetal copolymer having a melt flow ratio (MFR) measured at 190 ° C. and a load of 2160 g by the measuring method of ASTM D-1238 of 0.4 to 50 g / 10 min was obtained. preferable. Examples of these copolymerization components include ethylene oxide and cyclic ethers.

The blending ratio of the resin used in the present invention to the polyester is 0.1 ppb to 0.1 ppb.
ppb to 50,000 ppm, preferably 0.3 ppb
10,000 ppm, more preferably 0.5 ppb-10
0 ppm, more preferably 1.0 ppb to 1 ppm,
Particularly preferably, it is 1.0 ppb to 45 ppb. If the compounding amount is less than 0.1 ppb, the crystallization speed will be very slow and the mouthpiece of the hollow molded article will not be sufficiently crystallized. Therefore, if the cycle time is shortened, the amount of shrinkage of the mouthpiece will be regulated. Capping failure occurs because it does not fall within the value range, and the stretch heat-fixing mold for molding the heat-resistant hollow molded product is heavily contaminated, and the mold is frequently cleaned when trying to obtain a transparent hollow molded product. There must be. Again 50,000
If the content exceeds 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 defective capping. Of the hollow molded body and the preformed body for the hollow molded body is whitened, which makes normal stretching impossible. Further, in the case of a sheet-like material, if it exceeds 50,000 ppm, the transparency becomes extremely poor and the stretchability becomes poor so that normal stretching is impossible, and only a stretched film with large thickness unevenness and poor transparency is obtained. I can't.

When the member made of the resin and the polyester are contact-treated, it is desirable that the resin is present in a state of being adhered to the surface of the polyester chip. However, the impact force when the polyester chip collides with the member or The resin is not adhered to the polyester chip due to the size of the pressure contact force or the like, or the impact resistance and peeling resistance of the resin member, that is, a state independent of the polyester chip. For example, some of the fine particles are in a mixed state with the contact-treated polyester chips. The molded product obtained from the polyester in the state in which the fine resin particles are mixed as described above has a very high crystallization rate, and a very large fluctuation in the rate. In the case of a preformed body for a hollow molded body, the preformed body has severe whitening and transparency unevenness, and normal stretching cannot be performed, resulting in large thickness unevenness, and only a hollow molded article having poor transparency is obtained. I can't. 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 resin becomes foreign matter in the obtained molded body,
As a result, the obtained molded product has many defects such as uneven thickness, voids, and whitening. Therefore, it is desirable to remove the fine particles, particles or lumps of the resin existing independently of the polyester chips before molding.

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

The melt-polycondensed polyester is chipped and then transported to a silo or the like in a transport pipe for storage, or to a solid phase polymerization 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. A part of the fines and most of the film-like materials thus produced have a very high melting peak temperature of over 265 ° 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, Fines and film-like substances having a melting peak temperature exceeding 265 ° C. are generated. It is presumed that this is because the chip heats up due to a large force such as an impact force applied to the chip surface, and at the same time, oriented crystallization of polyester occurs 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 and then water treatment. The peak temperature becomes higher than that before the treatment. Fines and film-like substances having a melting peak temperature of 265 ° C. or less, but much higher than the normal melting peak temperature, have a melting peak temperature of more than 265 ° C. by the above-mentioned treatments. It has a melting peak temperature. 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 fast and the crystallization of the plug part of the hollow molding container becomes excessive, so that the shrinkage amount of the plug part does not fall within the specified range and the capping of the plug part is defective. Next, there arises a problem that the contents leak. In addition, the hollow-molding preform is whitened, which makes normal stretching impossible, resulting in uneven thickness, and the high crystallization rate results in poor transparency of the obtained hollow-molded product and also in transparency. Fluctuations will be large.

When it is desired to obtain a hollow molding preform or sheet having good transparency and stretchability from polyester containing fines having a melting peak temperature exceeding 265 ° C, 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 resin, the resin is often inferior in thermal stability to the polyester of the present invention, and thus molding at a high temperature of 300 ° C. or higher as described above. In the above, since thermal decomposition is caused to generate a large amount of by-products, the flavor and the like of the content of the obtained molded product or the like will be further affected.

Generally, polyester contains about 100 ppm to about several weight% of the fines including the fines and film-like substances described above, depending on the manufacturing method, and such fines are evenly distributed on the polyester chips. It is unevenly distributed rather than existing in a mixed state. Therefore, when such a polyester is subjected to a contact treatment with a member made of a resin such as a polyolefin resin under flowing conditions, the crystallization rate is further increased, but only the polyester having a very varied rate is obtained, which is 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 content of the film-like material, or the total content of the fine content and the content of the film-like material. By lowering the content of any one of them to 300 ppm or less, preferably 100 ppm or less, more preferably 50 ppm or less, the above problems can be solved further.
The content of either the fine content of the polyester before the contact treatment with the member and / or after the contact treatment, the film-like material content, or the total content of the fine content and the film-like material content is 300 ppm. If it exceeds, the crystallization rate of the molded product from the obtained polyester at the time of heating will be too high, and the crystallization of the plug part of the hollow molding container will be excessive, so that the shrinkage amount of the plug part is within the specified value range. However, there is a problem in that the cap is not capped and the contents leak out. In addition, the hollow-molding preform is whitened, which makes normal stretching impossible, resulting in uneven thickness, and the high crystallization rate results in poor transparency of the obtained hollow-molded product and also in transparency. Fluctuations will be large.

In the present invention, the peak temperature of the highest melting peak temperature of fine contained in the polyester before and / or after the contact treatment with the member is 265 ° C. or less. The present invention solves the above problems even further.

Examples of the method for separating and removing the fine and / or film-like material from the polyester before and / or after the contact treatment with the member include the following methods. That is, there may be mentioned a treatment method such as a vibrating sieving step and an air stream classification step by an air flow which are separately installed immediately before the solid phase polymerization step and immediately before or after the step of contacting with the resin member.

Further, as a method for preventing inclusion of fines having a melting peak temperature on the highest side of the melting peak temperature exceeding 265 ° C., a step of removing fines as described above after contact treatment with the resin is carried out. There is a method of treating with.

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 reason, contact treatment with a member made of the resin is performed. It is also necessary to pay attention to the content of the fine or film-like substances contained in the previous polyester and their properties.

A specific example of a method for preventing the polyester before the contact treatment with the resin member from containing such fines having a high melting point will be described below. In the case of melt polycondensation polyester, after melt polycondensation, the melt polyester is extruded into water from a die and cut in water, or extruded into the air and immediately cut into chips while cooling with cooling water. After draining the polyester chips formed into chips, a vibrating screen process and an air flow classification process using an air flow,
Alternatively, chips, fines, and film-like substances having a shape other than a predetermined size are removed by a water washing treatment step and sent to a storage tank by a plug transportation method or a bucket type conveyor-transportation method. Chips are taken out from the tank by a screw feeder, and transported to the next step by a plug transportation method or a bucket conveyor transportation method, and air flow classification by an air flow immediately before or after the contact treatment step. Fine removal processing is performed depending on the process. Then, the molten polycondensed polyester that has been subjected to the fine or film-like matter removal treatment is again removed by the airflow classification step using an air stream immediately before the solid-state polymerization step, and the solid-state polymerization step is performed. throw into. When transporting the melt-polycondensed prepolymer chips to a solid-state polymerization facility or when transporting the polyester chips after solid-state polymerization to a sieving step, the contact treatment step or a storage tank, most of these transportations are performed. Adopting a plug transportation system or a bucket type conveyor transportation system, and using a screw feeder to extract chips from the crystallization device or solid-state polymerization reactor, the equipment of chips and process and the transportation piping Use a device that can suppress the impact with the like.

Further, in the present invention, as cooling water in the chip forming step, sodium content (N), magnesium content (M), silicon content (S) and calcium content (C) are as follows. It is even more preferable to form the melt polycondensed polyester into chips using cooling water that satisfies at least one of (1) to (4), and particularly all of them. N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4)

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

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

When cooling water that does not satisfy the above conditions is used, these metal-containing compounds adhere to the surface of the polyester chip, and the final solid phase-polymerized polyester obtained has a very high crystallization rate. It is not preferable because the fluctuation becomes large. In addition, when solid-state polymerization of molten polycondensed polyester that is chipped while cooling with cooling water that deviates from the above conditions, the above-mentioned metal that is attached to the chip surface in the chipping step and brought into the solid-state polymerization reactor The contained substance adheres to the vessel wall of the solid-state polymerization device together with a part of the surface layer of the polyester chip, and this is heated to a high temperature of about 170 ° C. or more for a long time to form a scale having a high metal content. It adheres to the wall. Then, this is sometimes peeled off and mixed in the polyester chip, and becomes a foreign substance in a molded article such as a bottle, which lowers the commercial value.

Further, when the sheet is produced, the scale described above is clogged with the molten polymer filtration filter at the time of film formation, so that the filtration pressure of the filter increases sharply, resulting in poor operability and productivity. There is also the problem of becoming. The method of suppressing the sodium content, magnesium content, silicon content, and calcium content of the cooling water of the chips to the above ranges is illustrated below, but the present invention is not limited thereto.

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

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

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

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

As a method for reducing the number of particles in water to 50,000 particles / 10 ml or less, an apparatus for removing particles is installed at at least one location until natural water such as industrial water is supplied to the chip forming step. Preferably, from a natural water sampling port, a device for removing particles is installed during the chip formation step, and the water is supplied to the chip formation step.
The content of particles having a particle size of 1 to 25 μm is 50,000 / 10
It is preferably less than or equal to ml. Examples of the device for removing particles include a filter filtration device, a membrane filtration device, a sedimentation tank, a centrifuge, and a foam entrainment treatment device. For example, in the case of a filter filtration device, examples thereof include a belt filter system, a bag filter system, a cartridge filter system, a centrifugal filtration system and the like. Among them, the belt filter method, centrifugal filtration method,
A bag filter type filtration device is suitable. If it is a belt filter type filtering device,
Examples include paper, metal and cloth. Further, the size of the mesh of the filter is 5 to 100 μm, preferably 10 to 70 μm, and more preferably 15 to 40 μm in order to efficiently remove particles and efficiently introduce water.

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

Furthermore, in the present invention, the polyester before the contact treatment with the resin member is 290 ° C.
The polyester whose amount of cyclic trimer increase when melted at 60 ° 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.

Polyesters having a cyclic trimer increase of 0.50% by weight or less when melted at a temperature of 290 ° C. for 60 minutes are obtained by using a polyester polycondensation catalyst obtained after melt polycondensation or after solid phase polymerization. It can be manufactured by deactivating. Examples of the method of deactivating the polyester polycondensation catalyst include a method of subjecting the polyester chips to contact treatment with water, steam, or a steam-containing gas after solid-phase polymerization.

A method of contacting 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 performing water treatment is 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 treated with water 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, water treatment is performed by satisfying at least one of the following (5) to (9). Is desirable. 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 water to be 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 set. The contained substance floats or precipitates in the treated water, or even adheres to the walls of the processing tank or piping, which adheres to and permeates the polyester chips, promotes crystallization during molding, and makes bottles with poor transparency. Can be prevented.

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

Further, the water introduced from 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 to be reused after the treatment such as filtration. is there. When the polyester chips and steam or steam-containing gas are contacted for treatment,
Steam or steam-containing gas or steam-containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C., is preferably supplied in an amount of 0.5 g or more as steam per 1 kg of granular polyethylene terephthalate, or is present. Then, the granular polyethylene terephthalate is brought into contact with steam. The contact between the polyester chips and the steam is usually 10 minutes to 2 days, preferably 20 minutes to
It will be held for 10 hours.

The method of industrially carrying out the contact treatment between the particulate 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 the contact treatment with steam in a batch system, a silo type treatment apparatus can be used. That is, the polyester chips are received in a silo, and steam or a steam-containing gas is supplied in a batch method to perform contact treatment.

When the polyester chips are continuously contacted with steam, granular polyethylene terephthalate is continuously received from the upper part in a tower type processing apparatus, and steam is continuously supplied in a 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.

As another means for deactivating the polycondensation catalyst, there may be mentioned a method of deactivating the polymerization catalyst by adding and mixing a phosphorus compound to the melt of the polyester after solid phase polymerization.

As a method of blending the phosphorus compound with the solid-phase-polymerized polyester, a method of dry blending the phosphorus compound with the solid-state-polymerized polyester or a polyester master-batch chip and a solid-state polymerized polyester chip prepared by melt-kneading the phosphorus compound A method in which a predetermined amount of a phosphorus compound is blended with polyester by a method of mixing and then melted in an extruder or a molding machine to inactivate the polycondensation catalyst, and the like.

The phosphorus compound used is phosphoric acid,
Examples include phosphorous acid, phosphonic acid and their derivatives. Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, methylphosphonic acid,
Methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, and the like, which may be used alone or in combination of two or more. You may use together.

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 resin, 1,000,000 particles having a particle size of 0.3 to 5 μm (pieces / piece) It is desirable to use a gas introduced from outside the system, which is less than or equal to cubic feet, preferably less than or equal to 500,000 (pieces / cubic feet), and more preferably less than or equal to 100,000 (pieces / cubic feet). Particles exceeding 5 μm in gas are
Although not particularly limited, it is preferably 5 (pieces / cubic foot) or less, more preferably 1 (pieces / cubic foot).
G) The following.

In the production process of polyester, 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 phase 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 resin, when the air having the quality as described above is used as the gas that comes into contact with the polyester, the crystallization rate and the transparency of the obtained molded product largely vary. There is a high possibility that it will become a problem.

Therefore, in the method for producing polyester by the contact treatment with the resin member of the present invention, after the melt polycondensation, the solid phase polymerization, the water treatment or the contact treatment with the resin member, Among the polyesters, at least one polyester has a particle size of 0.3 to 5 as a gas to be contacted in any one of a transporting step to the next step, a sieving step, a storing step and a container filling step.
It is desirable to use a gas having a particle diameter of μm of 1,000,000 (particles / 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 a smaller amount is preferable in order to obtain a resin giving a transparent molded body.
The number of particles having a particle size of less than 0.3 μm is preferably 100.
It is 00000 (pieces / cubic feet) or less, more preferably 5,000,000 (pieces / cubic feet) or less, and further preferably 2000000 (pieces / cubic feet or less).

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

Particle size in gas introduced from outside the system 0.3 to 5
As a method of reducing the number of particles of μm to 1,000,000 (pieces / cubic foot) or less, cleaning by removing the particles at least at one or more places during the process until the gas introduced from outside the system contacts the polyester chips Install the device. When the gas is air in the vicinity of the treatment facility, JIS B 9908 is used during the process in which the air introduced by the blower from the air inlet comes into contact with the polyester chips.
A gas purifier equipped with a type 1 or / and type 2 filter unit defined in (1991) is installed, and the number of particles having a particle size of 0.3 to 5 μm in the air is set to 1,000,000.
(Individual / cubic foot) It is preferable to make it below. Also,
According to JIS B 9908 (199)
It is possible to extend the life of the filter unit by installing the gas cleaning device equipped with the type 3 filter unit defined in 1) and using it together with the gas cleaning device equipped with the filter unit. .

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

In addition, JIS B 9908 (1991)
Examples of the material for the high-performance filter unit of the type 2 defined in 1. include a filter made of polypropylene fiber, a filter made of a laminate of Teflon (R) 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.

The polyester obtained by the production method of the present invention has a thickness of 2 m obtained by melt-molding the polyester.
Crystallization temperature (Tc
1) is in the range of 150 to 168 ° C, preferably 155-1
It is preferably in the range of 65 ° C. When Tc1 exceeds 168 ° C., the heating crystallization rate becomes very slow, and the effect of improving crystallization cannot be expected. Further, when Tc1 is less than 150 ° C., the transparency of the hollow molded article decreases, which becomes a problem.

The polyester obtained by the production method of the present invention is a PET obtained by using a raw material such as dimethyl terephthalate or terephthalic acid, which is obtained by purifying a used PET bottle by the chemical recycling method, as at least a part of the starting material, Flake PE that is used PET bottle purified by mechanical recycling method and collected
It can be used as a mixture with T or PET in the form of chips.

The polyester obtained by the production method of the present invention may optionally contain other additives such as known ultraviolet absorbers, antioxidants, oxygen absorbers, oxygen scavengers,
A lubricant added from the outside or a lubricant that is internally precipitated during the reaction,
You may mix | blend various additives, such as a mold release agent, a nucleating agent, a stabilizer, an antistatic agent, and a pigment.

When the polyester obtained by the production method of the present invention is used for a sheet or the like, in order to improve handling properties such as slipperiness, winding property, blocking resistance and the like, the polyester is used. Calcium carbonate,
Inorganic particles such as magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, and magnesium phosphate, organic salt particles such as terephthalate salts such as calcium and calcium oxalate, barium, zinc, manganese, and magnesium, and divinyl. Inert particles such as crosslinked polymer particles such as homopolymers or copolymers of benzene, styrene, acrylic acid, methacrylic acid, vinyl monomers of acrylic acid or methacrylic acid can be contained.

The hollow molded article using the polyester obtained by the production method of the present invention can be manufactured by a commonly used melt molding method.
That is, it can be molded by a method such as an injection blow, a direct blow, and a stretching blow. In the case of producing a stretched hollow molded article, a transparent hollow molded article having excellent heat resistance can be produced from the polyester of the present invention by using a known hot parison method or cold parison method.

When a stretched hollow molded article is produced using the polyester obtained by the production method of the present invention, a preformed article is first formed by injection molding and then stretch blow-molded to form a bottle. Injection molding is generally performed at an injection temperature of about 265 to about 300 ° C., about 30 to about 70 kg.
It is carried out at an injection pressure of / cm 2 to form a preform. The plug portion of this preform is heat-treated to crystallize it. The preformed body thus obtained is preheated to about 80 to about 120 ° C. in the cold parison method and cooled to about 80 to about 120 ° C. in the hot parison method. Approximately 120 times this preform in a blow mold.
Stretch blow-molded at about 210 ° C, then about 0.5-
Heat treatment for about 30 seconds. The stretching ratio is usually 1.3 to 3.5 times in the machine direction and 2 to 6 times in the circumferential direction.
The polyester obtained by the production method of the present invention can also be used for a multilayer hollow molded article.

[0125]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The method of measuring the main characteristic values will be described below.

(1) Intrinsic viscosity of polyester chips (hereinafter referred to as "IV") From the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent I asked. As a sample for measuring the intrinsic viscosity of the polyester chip, solid-phase-polymerized polyester is frozen and pulverized before use. The intrinsic viscosity of the "dissolved polyester" obtained by the method (2) below is also measured under the same conditions.

(2) Intrinsic viscosities of the surface layer portion of the polyester chip and the central portion of the chip (hereinafter referred to as "IVs",
"IVc") Solid-phase-polymerized polyester (4 g) is placed in an Erlenmeyer flask containing a mixed solvent of 100 ml of hexafluoroisopropanol and 50 ml of chloroform, and left standing at 25 ° C for a predetermined time for dissolution treatment. After dissolving for a predetermined time, the solvent containing the dissolved polyester is transferred to an eggplant flask, the undissolved polyester chips are washed with chloroform, and this washing solution is mixed with the solvent in the eggplant flask. The solvent and chloroform in the eggplant flask were removed by evaporation, and the polyester remaining in the eggplant flask (hereinafter "dissolved polyester"
Sample), dried under vacuum with heating to remove the solvent and the like, and the weight (W ₁ ) is determined. The intrinsic viscosity (IV ₁ ) of this “dissolved polyester” is measured by the method (1). Next, the undissolved polyester chips are again allowed to stand for a certain period of time by the same operation as above to dissolve, and then the weight (W ₂ ) and the intrinsic viscosity (IV ₂ ) of the “dissolved polyester” are determined in the same manner. Standing between the take 4-5 points so that the appropriate interval, determine the weight (W _n) and intrinsic viscosity (IV _n) for each time in the same manner as described above, "dissolved Polyester". From the following formula, the weight% (W%) from the chip center is obtained, and a graph of W% and the corresponding intrinsic viscosity of "dissolved polyester" is drawn.
From this graph, the intrinsic viscosity corresponding to 20% by weight from the chip center is defined as the intrinsic viscosity (IVc) of the chip center, and the intrinsic viscosity corresponding to 90% by weight from the chip center is represented in the surface layer of the chip. Determined as intrinsic viscosity (IVs). Weight% from chip center = {1- (W ₁ + W ₂ + ...
_{· + W n) / W}} -W n / 2W} × 100

(3) 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.

(4) 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.

(5) 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 extracted at 160 ° C. for 2 hours. After treatment and cooling, acetaldehyde in the extract was measured by high sensitivity gas chromatography and the concentration was expressed in ppm.

(6) 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)

(7) 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.

(8) Measurement of fine peak temperature of fine particles Differential scanning calorimeter (DS) manufactured by Seiko Denshi Kogyo KK
C), measured using RDC-220. In (7),
Fines collected from 20 kg of polyester were dried under reduced pressure at 25 ° C for 3 days, and a sample of 4 m was used for each measurement.
DSC measurement at a temperature rising rate of 20 ° C./min using g,
The melting peak temperature on the highest side of the melting peak temperature is determined. The measurement is performed on a maximum of 10 samples, and the average value of the melting peak temperatures on the highest temperature side is obtained.

(9) Average Density of Polyester Chip and Density of Preform Mouth Portion Measured at 30 ° C. with a density gradient tube of a calcium nitrate / water mixed solution.

(10) Haze (% haze) and difference between maximum and minimum values of haze (hereinafter referred to as "R of haze") Molded body of the following (13) (wall thickness 5 mm) and hollow molding of (14) Cut a sample from the body of the body (wall thickness about 0.45 mm) and make it a model NDH, a haze meter manufactured by Nippon Denshoku Co., Ltd.
Measured at 2000. Further, the haze of the molded plate (wall thickness 5 mm) molded by the method of (13) was measured for the samples sampled every day for one consecutive month, and the “R of haze” for one month was obtained by the following. R (%) of haze = maximum value of haze of molded plate for 1 month-1 minimum value of haze of molded plate for 1 month

(11) 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).

(12) Density increase due to heating of preform plug part The preform plug part was heat treated for 60 seconds by a home-made infrared heater, and a sample was sampled from the top surface to measure the density.

(13) Molding of Stepped Molded Plate The dried polyester was used as 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.
The container was heat-set in a mold set to 0 ° C. to form a container (body thickness 0.45 mm) having a capacity of 2000 cc. The stretching temperature was controlled to 100 ° C.

(15) Leakage Evaluation of Contents from Hollow Molded Body The hollow molded body molded in (14) was filled with 90 ° C. hot water, 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) Foreign matter of hollow molded body Three hollow molded bodies of the following (14) were visually observed to obtain an average value, and evaluated as follows. ◎: There is no foreign matter ○: Very small amount of foreign matter (3 or less foreign matter having a size of 0.5 mm or less per hollow molded body) △: 0.5 mm or more per hollow molded body 5 to 10 foreign matter x: Very large number (more than 10 foreign matter having a size of 0.5 mm or more per hollow molding)

(17) Sodium content, calcium content, magnesium content and silicon content in the cooling water of the chip forming step and the introduced water of the water treatment step Collect the cooling water or the introduced water after particle removal and ion exchange. 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.

(18) Measurement of Number of Particles in Cooling Water in Chiping Step and Water Introduced during Water Treatment and Recycled Water Cooling water after particle removal and ion exchange, introduced water, or filtration device (5) and adsorption tower (8) ) The recycled water treated in (1) was measured using a particle measuring instrument PAC 150 manufactured by Seishin Enterprise Co., Ltd., which was a light blocking method, and the number of particles was expressed as 10/10 ml.

(19) Measurement of the Number of Particles in Gas Contacting Polyester Chips The gas sent by a blower or the like for forcibly sending the gas and passing through the gas cleaning device is branched from the main gas stream before contacting 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 fed to a first esterification reactor containing a reactant in advance, and the mixture was stirred for about 2 minutes.
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
Polycondensation was performed at 65 ° C. and 3 torr for 1 hour, and further with stirring in the final polycondensation reactor at about 275 ° C. and 0.3 to 1 torr. The intrinsic viscosity of the obtained melt polycondensed PET is 0.59.
The volume was deciliter / gram, and the carboxyl end group concentration was 9 equivalents / ton (ratio to the total end groups was about 8%).

Filter industrial water (derived from underground river water)
Approximately 510 particles / 10 m of particles having a particle size of 1 to 25 μm, which have been treated with a filtration device, an activated carbon adsorption device and an ion exchange device.
1, sodium content 0.03ppm, magnesium content 0.02ppm, calcium content 0.02
Introduced water having a ppm and a silicon content of 0.09 ppm is introduced into a cooling water storage tank in the chip forming step. The molten polycondensation PET extruded continuously in the form of a strand is chipped while being cooled with cooling water of 20 ° C. from the tank, and then is transported to a storage silo, and then vibrated and screened and air flow is applied. By removing fines and film-like substances by the classification process, the total content of these is 40ppm.
The following was carried out, and then it was transported to a continuous solid phase polymerization apparatus. Crystallize at about 155 ° C in a nitrogen atmosphere, preheat to about 200 ° C in a nitrogen atmosphere, send to a continuous solid-state polymerization reactor, perform solid-phase polymerization at about 205 ° C in a nitrogen atmosphere, and perform chip temperature within 1 minute. Was rapidly cooled to 50 ° C. or lower. The above-mentioned solid-state polymerization PET chip was processed by the vibrating sieving process and the airflow classifying process to adjust the fine content to 45 ppm. The cyclic trimer increase was 0.40% by weight.

Next, a linear low-density polyethylene (MI = about 0.9 g) was added to a part of the SUS304 transportation pipe connected to the transportation container filling step installed after the airflow classification step.
/ 10 min, density = 0.923 g / cm ³ ) inner diameter 7
The contact treatment was carried out by transporting in a transport pipe connected with a cylindrical pipe having a length of 0 mm and a length of 700 mm at about 3 tons / hour. The ratio A of the surface area (cm ² ) of the cylindrical pipe to the throughput (ton / hour) of the polyester chip is about 513.
Met. After the contact treatment, it was further treated in the airflow classification step.

The obtained PET had an intrinsic viscosity of 0.74 deciliter / gram, a DEG content of 2.7 mol%, a cyclic trimer content of 0.34 wt%, and an intrinsic viscosity (IVs ) To the intrinsic viscosity (IV) of the chip is 1.2.
0, the ratio of the intrinsic viscosity (IVc) at the center of the chip to the intrinsic viscosity (IV) of the chip was 0.95, and the average density was 1.403 g /
cm ³ , AA content is 3.3 pm, fine content is about 45 ppm, the peak temperature of the highest melting peak temperature of fine is 245 ° C., and polyethylene content is about 10 p.
It was pb.

The water discharged from the chip forming step is treated with a fine removing device which is a continuous filter having a filter medium made of paper and having a thickness of 30 μm, and then almost the entire amount is returned to the cooling water storage tank and mixed with the introduced water. This cooling water is continuously circulated and the shortage is replenished from outside the system to be used as cooling water. In addition, JIS B 9908 is used as air for contacting the melt polycondensation PET chip and the solid-state polymerization PET chip with the chip before filling and storing the container for transportation and the container for storage.
(1991) Type 3 PET non-woven filter unit equipped with an air purifier and JIS B 9908 (1)
991) Type 1 particle collection rate 99% or more HEPA filter unit equipped with an air purifier equipped with filtered air (particle size 0.3 ~ 5μm about 500 particles / cubic feet) did.

This PET was evaluated with a molded plate and a biaxially stretched molded bottle by the methods (13) and (14) described above. The stepped plate (5 mm thick) had a haze of 4.5%, a haze R of 0.5%, and a Tc1 of 16.
It is 5 ° C, and the density of the mouth of the bottle is 1.377g.
/ Cm ³ , and the foreign matter in the bottle was "⊚ (no foreign matter existed)", and there was no problem. The transparency of the bottle is 1.0
% Was good. In addition, in the leak test of the contents, there was no problem and the mouth plug was not deformed.

The solid-state polymerization reactions of Examples 1 and 2 and Comparative Examples 1 and 2 are as follows.
An overwhelmed and cleaned continuous solid phase polymerization apparatus was used, and solid phase polymerization PET 3 months after the start of continuous production was used for molding evaluation and bottle molding evaluation.

(Example 2) The solid-state polymerization PET obtained in Example 1 before contacting with PE was treated with water as follows. Raw material chip supply port (1) in the upper part of the treatment tank, overflow discharge port (2) located at the upper limit level of the treated water in the treatment tank, and discharge port (3) of the mixture of polyester chips and treated water in the lower part of the treatment tank. ), The treated water discharged from the overflow discharge port and the treated water discharged from the discharge port at the lower part of the processing tank through the polyester chip drainer (4) are continuous filters having a filter medium of paper. -Pipe (6) sent again to the water treatment tank via the fine filtration removal device (5) and the adsorption tower (8), GAF filter made by ISP-bag PE-1P2S (polyester felt, filtration accuracy 1 μm) ) Is a water removing port (7) which is obtained by introducing new ion-exchanged water from outside the system through an in-water particle removing device and an ion-exchange device into an inlet (9) in the middle of this pipe (6). ) Equipped with a capacity of 50m ³ Of the tower type of polyethylene terephthalate (hereinafter,
Abbreviated as PET) Chips were continuously treated with water.

The above-mentioned solid-state polymerized PET chips were treated by a vibrating sieving process and an air-flow classifying process to adjust the content of fine and film-like substances to about 40 ppm, and then the treated water temperature was controlled to 95 ° C. Water was continuously supplied from the supply port (1) at the upper part of the treatment tank, and the water treatment was performed while continuously extracting PET chips together with the treated water from the discharge port (3) at the lower part of the water treatment tank at a water treatment time of 3 hours. The content of particles having a particle size of 1 to 25 μm in the introduced water collected before the ion exchange water introducing port (9) of the above-mentioned treatment device is about 1600 particles / 10 ml,
Sodium content is 0.02ppm, Magnesium content is 0.02ppm, Calcium content is 0.03pp
m, the silicon content was 0.08 ppm, and the number of particles of the recycled water after the treatment in the filtration device (5) and the adsorption tower (8) having a particle size of 1 to 40 μm was about 18,000 particles / 10 ml.

After the treatment with water, 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 set to about 40 ppm. . Increase of cyclic trimer is 0.0
The peak temperature on the highest side of the melting peak temperature of 4% by weight, Fine, etc. was 245 ° C. The same equipment and method as in Example 1 were used to perform contact treatment with polyethylene and removal treatment such as fines.

The PET thus obtained had an intrinsic viscosity of 0.74 deciliter / gram, a DEG content of 2.7 mol%, a cyclic trimer content of 0.34 wt%, and an average density of 1.40.
3 g / cm ³ , AA content 3.3 ppm, fine content about 45 ppm, polyethylene content about 10 pp
It was b. In addition, solid-state polymerized PET chips are used as air to be sent to the subsequent steps and as dehumidifying air for drying.
Air purifier equipped with a filter unit made of PET non-woven fabric of type 3 of IS B 9908 (1991) and JIS
B 9908 (1991) Type 1 particle collection rate 99
% Air or more filtered by an air purifier equipped with a HEPA filter unit (the number of particles having a particle size of 0.3 to 5 μm is 53
0 / cubic foot) was used.

This PET was evaluated using a molded plate and a biaxially stretched molded bottle. The results are shown in Table 1. Molded plate haze is 5.0%, haze R is 0.5%, Tc
No. 1 was 161 ° C., the density of the spout was 1.379 g / cm ^3, which was a value with no problem. The foreign matter in the bottle was “⊚ (no foreign matter)”, and the transparency of the bottle was 1.1. % Was good. Also, there is no problem in the leak test of the contents,
There was no deformation of the mouth plug. The AA content of the bottle is 16.
The value was 0 ppm and there was 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.

(Comparative Example 1) Intrinsic viscosity was 0.50 deciliter / gram, and carboxyl end group concentration was 38 equivalents / ton (all ends were the same as in Example 1 except that esterification conditions and melt polycondensation conditions were changed. The ratio to the group is about 2
5%) melt polycondensed PET was obtained. Then, the 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 40%.
It was adjusted to be less than or equal to ppm and then transported to a continuous solid-state polymerization apparatus. Crystallize at about 155 ° C in a nitrogen atmosphere, preheat to about 200 ° C in a nitrogen atmosphere, send to a continuous solid-state polymerization reactor, perform solid-phase polymerization at about 220 ° C in a nitrogen atmosphere, and slowly cool in a nitrogen stream. did. This solid-phase-polymerized PET was treated to remove fines and the like in the same manner as in Example 1 and then subjected to contact treatment with polyethylene by the same method and conditions as in Example 1.

The PET thus obtained had an intrinsic viscosity of 0.75 deciliter / gram, a DEG content of 2.7 mol%, a cyclic trimer content of 0.32 wt%, and an intrinsic viscosity (IVs) of the surface layer of the chip. ) And the intrinsic viscosity (IV) of the tip are 1.5.
5, the ratio of the intrinsic viscosity (IVc) at the center of the chip to the intrinsic viscosity (IV) of the chip was 0.88, and the average density was 1.402 g /
cm ³ , AA content is 3.0 pm, fine content is about 50 ppm, peak temperature of the highest melting peak temperature of fine is 247 ° C., polyethylene content is about 1
It was 0 ppb.

Tc1 of the molded plate was low, haze and R of haze were large, the transparency of the bottle was problematic, the crystallization rate of the plug part was too fast, and the foreign matter in the bottle was "x (very many exist. ) ”, And had no commercial value. In addition, leakage of the contents was found in the leakage test of the contents.
The body haze of the bottle was very high at 8.9%, which was a problem.

Comparative Example 2 A melt polycondensed polyester is obtained in the same manner as in Comparative Example 1 except that the industrial water is used as it is as cooling water for chip formation without using the ion exchange apparatus used in Example 1. , Followed by solid state polymerization, followed by P
After carrying out the E contact treatment, it was subjected to molding. Particle size 1 to 25μ contained in industrial water used as cooling water for chip formation
Particles of m are about 600000 to 850,000 particles / 10m
1, sodium content 6.0-7.5 ppm, magnesium content 2.0-3.5 ppm, calcium content 3.4-6.0 ppm, silicon content 12.0-1
It was 5.8 ppm. The peak temperature on the highest side of the melting peak temperature of fines contained in this PET is
It was 275 ° C.

Table 1 shows the characteristics of the obtained PET, the molded plate obtained by molding the PET, and the biaxially stretched molded bottle. Obtained P
The intrinsic viscosity of ET is 0.75 deciliter / gram, DE
G content is 2.7 mol%, cyclic trimer content is 0.3
The content was 0% by weight, the average density was 1.402 g / cm ³ , the AA content was 3.2 ppm, and the fine content was about 40 ppm.

The molded plate has a low Tc1, a large haze and a large R of haze, there is a problem in the transparency of the bottle, the crystallization rate of the spout is too fast, and the foreign matter in the bottle is "× (very many exist. ) ”, And had no commercial value. In addition, leakage of the contents was found in the leakage test of the contents.
The body haze of the bottle was extremely high at 20.8%, which was a problem.

[0163]

[Table 1]

[0164]

EFFECT OF THE INVENTION According to the method for producing a polyester of the present invention, a hollow molded article having excellent transparency and flavor properties and containing almost no foreign matter is provided, and a polyester having improved operability is advantageously obtained. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a water treatment device used in Examples.

[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 AB04 AC01 AE03 BA03                       CB06A HA01 HB01 JA093                       JD03 JE043 JE133 JE203                       KF04 KH03 KH08 LB05 LB10

Claims (6)

[Claims] 1. A solid-phase-polymerized polyester chip whose main repeating unit is ethylene terephthalate is mixed with a member made of at least one resin selected from the group consisting of a polyolefin resin, a polyamide resin, and a polyacetal resin. A method for producing a polyester to be contact-treated under conditions, wherein the ratio of the intrinsic viscosity (IVs) of the polyester chip surface layer portion to the intrinsic viscosity (IV) of the chip is 1.10 to 1.30, and A method for producing polyester, wherein the ratio of the intrinsic viscosity (IVc) of the polyester chip center portion to the intrinsic viscosity (IV) of the chip is 0.90 to 0.97. 2. 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. A fine melting point fine contained in the polyester before and / or after the contact treatment.
The peak temperature on the highest temperature side is 265 ° C. or lower, and the method for producing polyester according to claim 1, wherein the peak temperature is 265 ° C. or lower. 4. The content of sodium (N), the content of magnesium (M), the content of silicon (S) and the content of calcium (C) of the polyester in a chipping step after melt polycondensation. Is a polyester chipped with cooling water that satisfies at least one of the following (1) to (4), and the method for producing a polyester according to claim 1. N ≤ 1.0 (ppm) (1) M ≤ 0.5 (ppm) (2) S ≤ 2.0 (ppm) (3) C ≤ 1.0 (ppm) (4) 5. The polyester before contact treatment with the member has a cyclic trimer increase amount of 0.50% by weight or less when melted at a temperature of 290 ° C. for 60 minutes. 5. The method for producing a polyester according to any one of 4 to 4. 6. The pipe, wherein the member is a pipe for pneumatic transportation of a polyester chip, a pipe for gravity transportation of a polyester chip, a rod-shaped pipe installed in a transfer path of the polyester chip,
It is at least 1 sort (s) selected from the group which consists of plate-like or net-like body, The manufacturing method of polyester in any one of Claims 1-5 characterized by the above-mentioned.