JP2001226476A - Polyester composition, sheet-like article, hollow molded article and oriented film comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester composition which has excellent transparency, heat resistance and mechanical characteristics, scarcely stains a mold, when molded, and gives hollow molded articles, sheet-like articles, and oriented films that scarcely have a residual foreign taste and a bad smell and have an excellent smell-retaining property, and containers and packaging materials obtained from the articles. SOLUTION: This polyester composition which comprises polyester chips and 0.1 to 300 ppm of the fine particles of a polyester having the same composition as that of the polyester chips and has a cyclic timer increase amount of <=0.30 wt.%, when melted at a temperature of 290 deg.C for 60 min, characterized by controlling the contents of Na element, Mg element and Si element in the fine particles of the polyester to specific ranges, respectively, and the hollow molded article, sheet-like articles and oriented film comprising the polyester composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition suitably used as a material for molded articles such as hollow molded articles such as beverage bottles, films, sheets and the like, and to molded articles formed therefrom. . In particular, the molded article obtained from the polyester composition of the present invention has excellent crystallization controllability, and the resulting molded article hardly generates residual off-flavor and odor, and is excellent in transparency and heat-resistant dimensional stability. And a sheet-shaped article and a stretched film which are excellent in transparency, slipperiness and dimensional stability after molding. Further, the present invention relates to a polyester composition having good releasability from a heat-treating mold when molding a small hollow molded article and having excellent long-term continuous moldability.

[0002]

2. Description of the Related Art Polyesters such as polyethylene terephthalate are excellent in both mechanical properties and chemical properties, and therefore have high industrial value, and include fibers, films, sheets, and the like.
Widely used as bottles.

[0003] As materials for containers such as seasonings, oils, beverages, cosmetics, and detergents, various resins are employed depending on the type of filling content and the purpose of use.

[0004] Among them, polyester is excellent in mechanical strength, heat resistance, transparency and gas barrier properties, and is therefore most suitable as a material for containers for filling beverages such as juices, soft drinks and carbonated drinks.

[0005] Such polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape, stretch-blown and then molded into a body of a bottle. Heat treatment (heat set)
In general, the bottle is formed into a hollow molded body, and the plug portion of the bottle is heat-treated (the plug portion is crystallized) as necessary.

However, conventional polyesters contain oligomers such as cyclic trimers and the like, and these oligomers adhere to the inner surface of the mold, the exhaust port of the mold gas, and the exhaust pipe. Dirt was easy to occur.

[0007] Such stains on the mold cause surface roughening and whitening of the obtained bottle. If the bottle becomes white, it must be discarded. For this reason, mold contamination must be removed frequently, and there has been a problem that the productivity of the bottle is reduced.

As a solution to these problems, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 4441 discloses a method of treating polyester with water. However, when performing this method industrially, since distilled water is disadvantageous in terms of cost if distilled water is used as treatment water, industrial water that is obtained by simply treating water, groundwater, drainage, and the like from rivers is used. That is common. However, when water treatment is performed using industrial water, there is a problem that crystallization during molding is often too early, resulting in a bottle having poor transparency. Further, there is also a problem that shrinkage of the plug portion due to crystallization of the plug portion does not fall within the standard, resulting in poor capping.

According to the study of the present inventors, this is because when the content of metal-containing substances such as sodium, magnesium, calcium, and silicon dioxide contained in industrial water is larger than a certain value at the stage of water treatment, Metal-containing substances such as oxides and hydroxides of these metals float and precipitate in the treatment water, and further adhere to the walls of treatment tanks and pipes, forming polyester chips and polyester fines (polyester fine powder). It was found that adhesion and permeation promoted crystallization during molding, resulting in a bottle with poor transparency.
In particular, polyester fine has a very large surface area as compared with chips, and the amount of metal-containing substances contained in the treated water is larger than that of chips, which further deteriorates the transparency of the bottle. Further, there have been problems such as the metal-containing substance clogging the piping and making the cleaning of the processing tank and the piping difficult.

[0010] Even in the case of a bottle resin in which the catalyst has not been deactivated by the conventional water treatment, water having high hardness was sometimes used when the strands were formed into chips, but no significant decrease in transparency was observed. However, the decrease in transparency due to the above foreign matter was particularly remarkable in bottles in which the catalyst was deactivated by water treatment or the like. This is not clear,
It is considered that the deactivation of the catalyst causes a germanium compound or the like contained in the resin as a catalyst to react with water to form particles insoluble in the resin, which may be a synergistic effect with the action of promoting crystallization by forming crystal nuclei.

In the water treatment stage, fines (resin fine powder) adhering to the polyester chips float and precipitate in the treated water and adhere to the treatment tank wall or the pipe wall, thereby clogging the pipe or treating. There have been problems such as making cleaning of tanks and pipes difficult.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, and it is difficult to generate mold stains during molding, and the transparency of the bottle and the crystallization of the plug are excellent. It is an object of the present invention to provide a polyester composition.

[0013]

In order to achieve the above-mentioned object, the polyester composition of the present invention comprises polyester chips and 0.1 to 300 ppm of fine polyester having the same composition as the polyester chips.
A polyester composition having a cyclic trimer increase of 0.30% by weight or less when melted at a temperature of 0 ° C. for 60 minutes, wherein the content of sodium in fines of the polyester is N (ppm), The content of calcium element is C (p
pm), the content of magnesium element is M (ppm), and the content of silicon element is S (ppm), the following (1)
It is a polyester composition characterized by satisfying at least one of formulas (4) to (4). (1) 0.002 ≦ N ≦ 5 (ppm) (2) 0.005 ≦ C ≦ 5 (ppm) (3) 0.005 ≦ M ≦ 5 (ppm) (4) 0.05 ≦ S ≦ 5 ( ppm)

The polyester composition having the above properties is
Hollow molding with less mold contamination during molding, excellent crystallization control of the plug, excellent transparency, heat resistance, mechanical properties, little residual off-flavor and off-flavor, and excellent fragrance retention Provides body, sheet, stretched film and packaging material.

The polyester composition of the present invention mainly uses terephthalic acid or its ester-forming derivative or naphthalenedicarboxylic acid or its ester-forming derivative and ethylene glycol as raw materials and a Ge compound and / or a Ti compound as a catalyst. The polyester composition obtained by subjecting the obtained polyester to water treatment can be a polyester composition.

In this case, the polyester is substituted with ethylene terephthalate as its main repeating unit by 9
The polyester composition may be a linear polyester containing 0 mol% or more. In this case, the polyester composition may be a linear polyester containing 90 mol% or more of ethylene-2,6-naphthalate, which is a main repeating unit thereof.

In this case, the polyester composition is used to form a polyester chip in a treatment tank as described below in (a).
And a polyester composition characterized by being treated with treated water satisfying the conditions of (b). (A) Temperature of 40 to 120 ° C (b) Treated water including wastewater from the treatment tank

In this case, the polyester composition is used to form a polyester chip in a treatment tank as shown in (c) below.
It can be a polyester composition characterized by being treated with treated water satisfying the following conditions. (C) Treated water having a polyester fine powder content of 1000 ppm or less

In this case, the polyester composition is used to form a polyester chip in a treatment tank as described in the following (1).
It can be a polyester composition characterized by being treated with treated water that satisfies at least one of formulas (4) to (4). (1) 0.001 ≦ N ≦ 1.0 (ppm) (2) 0.001 ≦ C ≦ 0.5 (ppm) (3) 0.001 ≦ M ≦ 0.5 (ppm) (4) 01 ≤ S ≤ 2.0 (ppm)

The polyester composition obtained by the above-mentioned water treatment hardly causes mold stains during molding, is excellent in crystallization controllability of the plug portion, and has excellent transparency, heat resistance and mechanical properties. A hollow molded article having less characteristics, residual off-flavors and off-flavors, and excellent in fragrance retention, and a sheet-like material having excellent transparency, slipperiness and dimensional stability after molding are provided.

In this case, a hollow molded article, a sheet-like article, and at least one of the above-mentioned polyester composition are formed.
It can be a stretched film stretched in one direction.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester of the present invention is a crystalline polyester obtained mainly from an aromatic dicarboxylic acid component and a glycol component, and is preferably a polyester containing an aromatic dicarboxylic acid unit in an amount of at least 85 mol% of the acid component. And more preferably a polyester containing an aromatic dicarboxylic acid unit in an amount of 90 mol% or more of the acid component.

The aromatic dicarboxylic acid component constituting the polyester of the present invention includes aromatic carboxylic acids such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid and diphenoxyethanedicarboxylic acid. And dicarboxylic acids and functional derivatives thereof.

Examples of the glycol component constituting the polyester of the present invention include aliphatic glycols such as ethylene glycol, trimethylene glycol and tetramethylene glycol, and alicyclic glycols such as cyclohexanedimethanol. Can be

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

Examples of the glycol component used by copolymerization in the polyester include aliphatic glycols such as ethylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol and neopentyl glycol, bisphenol A and bisphenol A. And alicyclic glycols such as cyclohexanedimethanol, and polyalkylene glycols such as polyethylene glycol and polybutylene glycol.

Further, polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, glycerin, pentaerythritol, and trimethylolpropane are copolymerized within a range where the polyester is substantially linear. Or a monofunctional compound such as benzoic acid or naphthoic acid.

One preferred example of the polyester of the present invention is
The main repeating unit is a polyester composed of ethylene terephthalate, more preferably a linear polyester containing at least 85 mol% of ethylene terephthalate units, particularly preferably a linear polyester containing at least 90 mol% of ethylene terephthalate units, that is, Polyethylene terephthalate (hereinafter abbreviated as PET).

Another preferred example of the polyester of the present invention is a polyester whose main repeating unit is composed of ethylene-2,6-naphthalate, more preferably 85% by mole or more of ethylene-2,6-naphthalate unit. A linear polyester containing ethylene-2,6-naphthalate units at 90 mol% is particularly preferable.
The linear polyester contained above, that is, polyethylene naphthalate homopolymer or polyethylene naphthalate copolymer containing ethylene terephthalate unit (hereinafter referred to as P
EN).

The intrinsic viscosity of the polyester of the present invention, especially the polyester whose main repeating unit is composed of ethylene terephthalate, is preferably 0.50 to 1.30.
Deciliter / gram, more preferably 0.55-1.
20 deciliter / gram, more preferably 0.60
０．９0.90 deciliter / gram. If the intrinsic viscosity is less than 0.50 deciliter / gram, the obtained molded article or the like has poor mechanical properties. On the other hand, if it exceeds 1.30 deciliters / gram, the resin temperature rises during melting by a molding machine or the like, and the thermal decomposition becomes severe. Problems such as yellowing occur.

The intrinsic viscosity of the polyester of the present invention, especially the polyester whose main repeating unit is composed of ethylene-2,6-naphthalate, is preferably 0.4.
The range is from 0 to 1.00 deciliter / gram, more preferably from 0.42 to 0.95 deciliter / gram, and even more preferably from 0.45 to 0.90 deciliter / gram. If the intrinsic viscosity is less than 0.40 deciliter / gram, the obtained molded article or the like has poor mechanical properties. Also 1.
If it exceeds 00 deciliters / gram, the resin temperature rises during melting by a molding machine or the like, and thermal decomposition becomes severe, free low-molecular-weight compounds that affect fragrance retention increase, or the molded product is colored yellow. Problems occur.

The shape of the polyester chip may be any of a cylinder type, a square type, a flat plate shape and the like, and the size thereof is usually in a range of 1.5 to 4 mm in length, width and height. For example, in the case of a cylinder type, the length is 1.
It is practical that the diameter is about 5 to 4 mm and the diameter is about 1.5 to 4 mm. Further, the weight of the chip is practically in the range of 15 to 30 mg / piece.

The fine content of the polyester composition of the present invention is 0.1 to 300 ppm, preferably 0.5 to 2 ppm.
00 ppm, more preferably 1 to 100 ppm, still more preferably 1 to 50 ppm. When the fine content is less than 0.1 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded article becomes insufficient, so that the shrinkage amount of the plug portion falls within the specified value range. Since it cannot be settled, a poor capping phenomenon occurs, and a sheet-like material having poor dimensional stability after forming the container is given. Also 300p
In the case of exceeding pm, the crystallization speed is increased, and the crystallization of the plug portion of the hollow molded article becomes excessively large. As a result, the shrinkage of the plug portion does not fall within the specified value range, so that the cap portion of the plug portion is defective. As a result, leakage of the contents occurs, and the preform for hollow molding is whitened, so that normal stretching cannot be performed.

Here, fine particles, powders and the like, which are considerably smaller than chips generated in the polyester production process including the following water treatment process, are referred to as fines. The copolymerization component of the fine and the content of the copolymerization component are the same as those of the polyester chip, and the intrinsic viscosity is usually the same as the intrinsic viscosity of the chip or 0.03 deciliter / gram higher than the intrinsic viscosity of the chip. It is preferably within the range of the intrinsic viscosity.

In the present invention, as a method for adjusting the fine content of the polyester composition to the above range,
In addition to the method of mixing the polyester chips with high fine content without passing through the sieving process and the polyester chips with very small fine content through the sieving process and the fine removing process with air flow at an appropriate ratio, It can also be adjusted by changing the size of the decoration, and any method such as changing the sieving speed can be used.

Further, in order to adjust the amount of fine polyester to 0.1 to 300 ppm in the polyester composition,
The following method is practical. That is, first, in the water treatment step described below, it is preferable that at least a part of the water to be treated is water that has been discharged from the treatment tank, returned to the treatment tank again, and used repeatedly. By reusing water, it is possible to control the amount of fine powder in the treated water, and it is easy to control the fine amount of the polyester composition. Fine powder amount is 0
When water of ppm is used for water treatment, fines adhering to chips may be washed away by water and may be less than 0.1 ppm. Here, the fine in the water treatment tank is called fine powder, and its content in the treated water, that is, the amount of fine powder, can be measured by the following measuring method.

Further, the amount of fine powder in the treated water is reduced to 1000 pp.
It is preferable to perform the treatment while adjusting the pressure to m or less.
If water having a fine powder amount exceeding 1000 ppm is used, the fine amount of the polyester composition may exceed 300 ppm.

Further, when a polyester composition which has been subjected to a water treatment, a drying step, a sieving step, and a step of finely removing the polyester by an air stream is used, or when the fine amount of the polyester composition is less than 0.1 ppm, this polyester composition is used. Adjusted by mixing a low-fine polyester composition with a polyester composition with a large amount of fine not passed through the fine removal process, or adding fines collected from the treated water in the water treatment process or recovered from the fine removal process can do.

In the polyester composition of the present invention, the content of sodium element in the fines of the polyester constituting the composition is N (ppm), the content of calcium element is C (ppm), and the content of magnesium element is fine. M (pp
m) wherein the content of the silicon element is S (ppm), and the polyester composition satisfies at least one of the following formulas (1) to (4). (1) 0.002 ≦ N ≦ 5 (ppm) (2) 0.005 ≦ C ≦ 5 (ppm) (3) 0.005 ≦ M ≦ 5 (ppm) (4) 0.05 ≦ S ≦ 5 ( ppm)

The value of N is preferably 0.005 to 1 pp
m, more preferably 0.01 to 0.5 ppm, still more preferably 0.01 to 0.3 ppm.

When the value of N is less than 0.002 ppm,
The crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded body becomes insufficient, and the shrinkage amount of the plug portion does not fall within the specified value range, so that a capping failure phenomenon occurs, or A sheet-like material having poor dimensional stability after container molding is provided.

The value of C is preferably 0.008 to 0.008.
It is 1 ppm, more preferably 0.01 to 0.5 ppm, and still more preferably 0.01 to 0.3 ppm. When the value of C is less than 0.005 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded article becomes insufficient, so that the shrinkage amount of the plug portion falls within the specified value range. Since it cannot be settled, a poor capping phenomenon occurs, and a sheet-like material having poor dimensional stability after forming the container is given.

The value of M is preferably 0.008 to 0.008.
It is 1 ppm, more preferably 0.01 to 0.5 ppm, and still more preferably 0.01 to 0.3 ppm. When the value of M is less than 0.005 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded article becomes insufficient, so that the shrinkage amount of the plug portion falls within the specified value range. Since it cannot be settled, a poor capping phenomenon occurs, and a sheet-like material having poor dimensional stability after forming the container is given.

The value of S is preferably 0.07-1.
ppm, more preferably 0.08 to 0.5 ppm, even more preferably 0.1 to 0.3 ppm. When the value of S is less than 0.05 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded body becomes insufficient,
For this reason, since the shrinkage amount of the plug does not fall within the specified value range, a poor capping phenomenon occurs, and a sheet-like material having poor dimensional stability after container molding is provided.

Further, if the values of N, C, M, and S are set to be less than the lower limits of the above formulas (1), (2), (3), and (4), distilled water or reverse It is necessary to use water having a very low content of sodium, calcium, magnesium and silicon, such as water treated with a permeable membrane and water subjected to highly ion-exchange treatment, which is economically undesirable.

When the values of N, C, M, and S exceed 5 ppm, the crystallization speed is increased, and the crystallization of the plug portion of the hollow molded body becomes excessive. Since it is not within the specified value range, capping of the plug portion becomes defective, causing leakage of the contents, and the preform for hollow molding becomes white, which makes normal stretching impossible. Preferably, the values of N, C, M and S are all 5 ppm or less.

Since sodium, calcium, magnesium and silicon are mainly derived from treated water, these metals are present in the surface layer of polyester fine.

Further, the polyester composition of the present invention
It is necessary that the amount of increase of the cyclic trimer when melted at a temperature of 90 ° C. for 60 minutes is 0.30% by weight or less. The amount of increase of the cyclic trimer is preferably 0.2% by weight or less, more preferably 0.1% by weight or less. 29
When the amount of the cyclic trimer increased by melting at 0 ° C. for 60 minutes exceeds 0.30% by weight, the amount of the cyclic trimer increases upon melting of the molding resin, and the oligomer adheres to the surface of the heated mold. Sharply increases, and the transparency of the obtained hollow molded article and the like is extremely deteriorated.

The polyester composition in which the amount of the cyclic trimer increases by 0.30% by weight or less when melted at a temperature of 290 ° C. for 60 minutes can be produced by contact treatment with treated water. . As a method of the contact treatment, a method of immersing in water may be mentioned. The time for performing the contact treatment with water is 5 minutes to 2 days, preferably 10 minutes to 1 day, more preferably 30 minutes to 10 hours, and the water temperature is 20 to 180 ° C, preferably 40 to 150 ° C. ° C, more preferably 50 to 120 ° C.

Further, the acetaldehyde content of the polyester composition of the present invention is preferably 8 ppm or less, more preferably 6 ppm or less, still more preferably 4 ppm or less, and the formaldehyde content is preferably 6 ppm or less, more preferably 5 ppm or less, and still more preferably. Is 4
ppm or less. Acetaldehyde content is 8ppm
When the formaldehyde content is at least 6 ppm, the contents such as containers molded from the polyester composition will have poor flavor and odor.

The amount of diethylene glycol copolymerized in the polyester of the present invention is preferably 1.0 to 5.0 mol%, more preferably 1.3 to 4.5 mol%, of the glycol component constituting the polyester. More preferably, it is 1.5 to 4.0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability becomes poor,
The decrease in molecular weight during molding is large, and the acetaldehyde content and the formaldehyde content are undesirably large. . When the content of diethylene glycol is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.

The content of the cyclic trimer of the polyester of the present invention is preferably 0.50% by weight or less, more preferably 0.45% by weight or less, further preferably 0.40% by weight or less. When a heat-resistant hollow molded article or the like is molded from the polyester composition of the present invention, heat treatment is performed in a heating mold. However, when the content of the cyclic trimer is 0.50% by weight or more, heating is performed. Adhesion of oligomers to the surface of the mold is sharply increased, and the transparency of the obtained hollow molded article or the like is extremely deteriorated.

The polyester composition of the present invention can be produced, for example, as follows. That is, a polyester chip formed into a chip after polycondensation is treated in a treatment tank by satisfying at least one of the following formulas (1) to (4) and containing a polyester fine powder of 0.1 to 1000 ppm. 50-100 with water
It can be manufactured by performing contact treatment at 30 ° C. for 30 minutes to 10 hours. (1) 0.001 ≦ N ≦ 1.0 (ppm) (2) 0.001 ≦ C ≦ 0.5 (ppm) (3) 0.001 ≦ M ≦ 0.5 (ppm) (4) 01 ≤ S ≤ 2.0 (ppm)

In the case of industrially treating polyester chips with water, natural water (industrial water) and wastewater are often reused because of the large amount of water used for the treatment. Normally, this natural water is collected from river water, groundwater, or the like, and refers to water that has been subjected to treatment such as sterilization and removal of foreign substances without changing the shape of water (liquid). In addition, natural water generally used for industrial purposes includes inorganic compounds such as silicates, aluminosilicates and other clay minerals derived from nature, bacteria, bacteria, etc., and originates from spoiled plants and animals. And many organic compounds having the following. When water treatment is performed using these natural waters, metal-containing substances such as sodium, magnesium, calcium, and silicon dioxide adhere to and infiltrate polyester chips and polyester fines to form crystal nuclei, and such a polyester composition is used. It was found that the transparency of the hollow molded article was very poor.

Regardless of whether the water treatment method is a continuous type or a batch type, if all or most of the treated water discharged from the treatment tank is converted into industrial wastewater, a large amount of new water is required. In addition, there is a concern about the impact on the environment due to increased wastewater volume. That is, at least a part of the treated water discharged from the treatment tank is returned to the water treatment tank and reused, thereby reducing a necessary water amount, and reducing an influence on an environment due to an increase in the amount of wastewater. If the wastewater returned to the water treatment tank maintains a certain temperature, the heating amount of the treated water can be reduced.

From the economic and environmental viewpoints, in the case of batch type water treatment, treated water is repeatedly used. In the case of continuous type water treatment, treated water discharged from the water treatment tank is returned to the treatment tank. In each case, fine particles derived from polyester chips and metal-containing substances such as sodium, magnesium, calcium and silicon dioxide in the treated water adhere to the treatment tanks and pipes of the water treatment apparatus, and This may cause contamination of the processing equipment.

A method for reducing the sodium content, magnesium content, calcium content, silicon dioxide content and the like of the treated water in the treatment tank will be described below.
It is not limited to this.

In order to reduce the sodium content, magnesium content, calcium content, silicon dioxide content, etc. of the treated water in the treatment tank, the industrial water is supplied to the treatment tank until it is sent to the treatment tank. An apparatus for removing sodium, magnesium, calcium, silicon dioxide and the like is installed at at least one place in the process. Further, in the process until the treated water discharged from the treatment tank is returned to the treatment tank again, an apparatus for removing sodium, magnesium, calcium, silicon dioxide, etc. may be provided at at least one or more places. As an apparatus for removing sodium, magnesium, calcium, silicon dioxide, etc., an ion exchange apparatus,
Drug precipitation equipment, electrolytic desiliconization equipment, etc.

In order to reduce the sodium content, magnesium content, and calcium content of the treated water introduced from outside the system to less than 0.001 ppm, it is necessary to repeatedly distill the water and repeat filtration through a reverse osmosis membrane. However, this increases the cost of water and is not economically favorable.

The following is an example of a method for industrially performing water treatment, but the method is not limited thereto. The processing method may be either a continuous method or a batch method, but the continuous method is preferable for industrial use.

When water treatment is performed on polyester chips in a batch system, a silo-type treatment tank may be used. That is, polyester chips are received in a silo in a batch system and water treatment is performed. Alternatively, it is also possible to receive the polyester chips in a rotating cylindrical processing tank and perform water treatment while rotating the polyester chips to make the contact with water more efficient.

In this case, the polyester chips were charged and filled in the treatment tank, and the sodium content was 0.005%.
1 to 1.0 ppm, the calcium content and the magnesium content are each 0.001 to 0.5 ppm, the silicon content is 0.01 to 2.0 ppm, and the treated water is continuous or intermittent as required. (Sometimes referred to collectively as continuous), and a part of the treated water is discharged continuously or intermittently to reduce the sodium content to 0.001 to 0.001.
New treated water having 1.0 ppm, calcium content and magnesium content of 0.001 to 0.5 ppm, respectively, and silicon content of 0.01 to 2.0 ppm is additionally supplied. The sodium content in the water at the end of the water treatment is 0.001 to 1.0 ppm, the calcium content and the magnesium content are 0.001 to 0.5 ppm, respectively.
ppm and a silicon content of 0.01 to 2.0 ppm can be used to process polyester chips having the following characteristics.

When the polyester chips are continuously treated with water, the polyester chips are continuously or continuously intermittently received from above, and water is continuously supplied in parallel or countercurrently to treat water. Can be done.

The treated water discharged from the water treatment tank contains fine particles that have already adhered to the polyester chips at the stage of receiving the polyester chips in the treatment tank, and friction between the polyester chips or the wall of the treatment tank during water treatment. Includes polyester fines generated in Therefore, when the treated water discharged from the treatment tank is returned to the treatment tank again and reused, the amount of fines contained in the treated water in the treatment tank gradually increases. For this reason, fine powder contained in the treated water may adhere to the treatment tank wall or the pipe wall and clog the pipe. In addition, fine powder contained in the treated water adheres again to the polyester chips, and then fines adhere to the polyester chips by an electrostatic effect at the stage of drying and removing moisture. Removal becomes difficult.

The water-treated polyester chips are drained by a draining device such as a vibrating sieve or a Simon Carter and transferred to a drying step. Naturally, the water separated from the polyester chips by the drainer is a filter-type filter,
It is sent to a fine removal device such as a centrifuge and can be used again for water treatment.

For drying the polyester chips, a commonly used drying treatment of the polyester chips can be used. As a method for continuous drying, a hopper-type through-air dryer that supplies a polyester chip from the upper portion and allows a drying gas to flow from the lower portion is usually used. As a method of reducing the amount of drying gas and drying efficiently, a rotating disk type continuous dryer is selected, and heating steam, heating medium, etc. are supplied to the rotating disk and the outer jacket while passing a small amount of drying gas. The dried granular polyester chips can be dried indirectly.

As a dryer for drying in a batch system, a double cone type rotary dryer is used, and drying can be performed under vacuum or while passing a small amount of drying gas under vacuum. Alternatively, the drying may be performed while passing a drying gas under atmospheric pressure.

As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferred from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of polyester.

The polyester subjected to the water treatment can be produced by a conventionally known production method. That is, in the case of PET, a direct esterification method in which terephthalic acid and ethylene glycol and, if necessary, other copolymerization components are directly reacted to distill off water and esterify, followed by polycondensation under reduced pressure, or It is produced by a transesterification method in which dimethyl terephthalate is reacted with ethylene glycol and, if necessary, other copolymerization components to remove methyl alcohol and transesterify, followed by polycondensation under reduced pressure. Further, solid-state polymerization may be performed to increase the intrinsic viscosity and reduce the acetaldehyde content and the like.

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

In the case of the transesterification method, transesterification is carried out using a transesterification catalyst, for example, a Ca compound, a Ma compound, a Mn compound, a Zn compound, a Co compound, and the like. After inactivating the transesterification catalyst, polycondensation is performed using a compound of Ge, Sb, and Ti as a polycondensation catalyst.
In particular, the use of Ge compounds and / or Ti compounds is advantageous.

In the case of the direct esterification method, a compound of Ge, Sb and Ti is used as a polycondensation catalyst, but the use of a Ge compound and / or a Ti compound is particularly convenient.

The Ge compound used in the present invention includes:
Amorphous germanium dioxide, crystalline germanium dioxide powder or a slurry of ethylene glycol, a solution obtained by heating and dissolving crystalline germanium dioxide in water, or a solution obtained by adding ethylene glycol to the solution and then heat-treating the same are used, and are particularly used in the present invention. In order to obtain a polyester, it is preferable to use a solution in which germanium dioxide is dissolved in water by heating, a colloidal solution, a solution in which ethylene glycol is added thereto and heated, or a solution of germanium dioxide in ethylene glycol. When a Ge compound is used, the amount used is 5 to 150 ppm, preferably 10 to 100 ppm, as a Ge residual amount in the polyester resin,
More preferably, it is 15 to 70 ppm.

The Ti compounds used in the present invention include:
Tetraethyl titanate, tetraisopropyl titanate
And tetraalkyl titanates such as tetra-n-propyl titanate and tetra-n-butyl titanate and their partial hydrolysates, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, titanyl oxalate Examples include calcium, titanyl oxalate compounds such as titanylstrontium oxalate, titanium trimellitate, titanium sulfate, and titanium chloride. The Ti compound is 0.1 to 10 as a residual amount of Ti in the produced polymer.
It is added to be in the range of ppm.

The Sb compound used in the present invention includes:
Examples include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. The Sb compound is added so that the residual amount of Sb in the resulting polymer is in the range of 50 to 250 ppm.

These polycondensation catalysts can be added at any stage before the transesterification or esterification reaction and before the polycondensation reaction.

As the stabilizer, it is preferable to use phosphoric acid, polyphosphoric acid, and phosphoric esters such as trimethyl phosphate. These stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the residual amount of P in the resulting polymer is in the range of 5 to 100 ppm.

Also, DEG copolymerized in polyester
In order to control the content, a basic compound, for example, a tertiary amine such as triethylamine or tri-n-butylamine, or a quaternary ammonium salt such as tetraethylammonium hydroxide can be added to the esterification step.

The polyester used in the water treatment has an acetaldehyde content of 10 ppm or less, a formaldehyde content of 8 ppm or less, a diethylene glycol content of 1.0 to 5.0 mol% of the glycol component, and a cyclic trimer content of 0.1 to 5.0 mol%. It is preferably 50% by weight or less.

The density of the polyester chips used in the water treatment ranges from about 1.33 (g / cm ³ ) to about 1.4.
It is preferably in the range of 2 (g / cm ³ ).

A saturated fatty acid monoamide, an unsaturated fatty acid monoamide, a saturated fatty acid bisamide, an unsaturated fatty acid bisamide and the like can be simultaneously used in the polyester composition of the present invention.

Examples of the saturated fatty acid monoamide include lauric amide, palmitic amide, stearic amide, behenic amide and the like. Examples of unsaturated fatty acid monoamides include oleic acid amide, erucic acid amido ricinoleic acid amide, and the like. Examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid Amides and the like. Examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide and hexamethylene bisoleic acid amide. Preferred amide compounds are saturated fatty acid bisamide, unsaturated fatty acid bisamide and the like. The compounding amount of such an amide compound is 1
The range is from 0 ppb to 1 × 10 ⁵ ppm.

Metal salt compounds of aliphatic monocarboxylic acids having 8 to 33 carbon atoms, such as naphthenic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid,
Stearic acid, behenic acid, montanic acid, melicic acid,
Lithium, sodium, potassium, magnesium, calcium, and cobalt salts of saturated and unsaturated fatty acids such as oleic acid and linoleic acid can be used in combination. The compounding amount of these compounds is 10p
The range is from pb to 300 ppm.

The polyester composition of the present invention can be preferably used as a hollow molding, a tray, a packaging material such as a biaxially stretched film, a film for coating a metal can, and the like. Further, the polyester composition of the present invention can also be used as one constituent layer of a multilayer molded article, a multilayer film and the like.

The polyester composition of the present invention may contain, if necessary, a known ultraviolet absorber, a lubricant added from the outside, a lubricant internally deposited during the reaction, a release agent, a nucleating agent, a stabilizer, and an antistatic agent. And various additives such as pigments.
The main method of measuring characteristic values in the present invention will be described below.

[0086]

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

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

(2) Polyethylene diethylene glyco-
The content was determined by decomposing with methanol and quantifying the amount of DEG by gas chromatography and expressed as a ratio (mol%) to the total glycol components.

(3) Density: Measured at 30 ° C. with a density gradient tube of a mixed solvent of calcium nitrate / water.

(4) Content of Polyester Cyclic Trimer (hereinafter referred to as “CT Content”) A sample (300 mg) was dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixture (volume ratio = 2/3). Further, 30 ml of chloroform is added for dilution.
To this, 15 ml of methanol was added to precipitate a polymer, followed by filtration. The filtrate was evaporated to dryness, the volume was adjusted to 10 ml with dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

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

(6) Sodium content, calcium content and magnesium content of polyester fine About 5 to 10 g of a sample was put in a platinum crucible and incinerated at about 550 ° C., dissolved in 6N hydrochloric acid, evaporated to dryness, and the residue was dried. 1N difference
Dissolve in hydrochloric acid. This solution was measured by atomic absorption spectrometry. In addition, polyester fine is JIS-Z88
The resin is sieved through a screen (diameter: 30 cm) with a wire mesh having a nominal size of 1.7 mm according to 01 and collected.

(7) Silicon Content of Polyester Fine About 5 to 10 g of a sample was put in a platinum crucible and incinerated at about 550 ° C., and then sodium carbonate was added to dissolve it by heating.
Dissolve in hydrochloric acid. This solution was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation.

(8) Fine content measurement About 0.5 kg of resin was put on a sieve (diameter 30 cm) equipped with a wire mesh having a nominal size of 1.7 mm according to JIS-Z8801, and 0.1% of cation was added from the top. An aqueous solution of an aqueous solution of a surfactant (alkyltrimethylammonium chloride) was sieved for 1 minute at a total amplitude width of about 7 cm and 60 reciprocations / 1 minute while being showered at a flow rate of 2 L / min. This operation was repeated, and the resin was sieved in a total of 10 to 30 kg. The fines removed by filtration were collected by filtration with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd. together with a surfactant aqueous solution, and washed with ion-exchanged water. Put this together with the glass filter in a dryer for 1
After drying at 00 ° C. for 2 hours, the mixture was cooled and weighed. The same operation of washing and drying with ion-exchanged water was repeated again to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain a fine weight. Fine content is
Fine amount / total weight of resin sieved.

(9) Evaluation of mold stain The polyester composition was dried with a drier using nitrogen, and a preform was molded at a resin temperature of 290 ° C. using an M-150C (DM) injection molding machine manufactured by Meiki Seisakusho. After the plug portion of this preform was heated and crystallized by a home-made plug portion crystallizer, biaxial stretch blow molding was performed using an LB-01 stretch blow molding machine manufactured by Co-Poplast Co.
The resultant was heat-set in a mold set at a temperature of 10 ° C. for 10 seconds to obtain a 500 cc hollow molded body. Under the same conditions, continuous stretch blow molding was performed, and the stain on the mold was evaluated by the number of moldings until the transparency of the container was impaired by visual inspection. Further, as a sample for haze measurement, a body portion of a container after continuous molding 5,000 times was provided.

(10) Haze (haze degree%) Body (thickness: about 0.40 mm) of the hollow molded article of (9) above
A sample was cut out from the sample and a haze meter manufactured by Nippon Denshoku
Was measured.

(11) Density increase due to heating of the bottle cap The bottle cap was heat-treated for 60 seconds with a homemade infrared heater, and a sample was taken from the top to measure the density.

(12) Amount of fine powder (pp
m) 1000 cc of treated water passed through a JIS standard 20 mesh filter was collected from the treated water outlet of the treatment tank.
After filtration with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., 100
After drying at room temperature for 2 hours and cooling at room temperature, the weight is measured and calculated.

(13) Sodium Content, Calcium Content, Magnesium Content and Silicon Content in Treated Water Treated water was collected from the treated water outlet of the treatment tank and filtered through 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.

(Example 1) An ion exchange device (9) was installed, an inlet (8) for ion-exchanged water via this device (9), a raw material chip supply port (1) at the top of the processing tank, and a processing tank. The discharge outlet located at the upper limit level of the treated water (2), the outlet for the mixture of polyester chips and treated water at the lower part of the treatment tank (3), the treated water discharged from the overflow outlet, and the outlet at the lower part of the treatment tank A pipe (6) for sending treated water from a polyester chip draining device (4) discharged from the tank to a water treatment tank again through a filtering device (5), which is a 30-μm belt-type filter made of paper. FIG. 1 shows a 500-liter column type equipped with an inlet (7) for these finely removed treated water and an adsorption tower (10) for adsorbing acetaldehyde and the like in the finely removed treated water. Using to process tank polyethylene terephthalate (hereinafter, PET abbreviated) and the chip water treatment. The limiting viscosity is 0.74 deciliter /
P having a gram, a density of 1.399 g / cm ³ , a cyclic trimer content of 0.32% by weight, a residual Ge amount of 51 ppm, and a residual P amount of 38 ppm as measured by atomic absorption analysis.
The ET chip was adjusted to a Na content of 0.
50 kg / hour into a water treatment tank containing treated water having a concentration of 0.05 ppm, a Ca content of about 0.1 ppm, a Mg content of about 0.03 ppm, a Si content of about 0.5 ppm, and a temperature controlled at 95 ° C. Upper part of processing tank at speed (1)
Started continuous feeding from. 5 hours after the start of the charging, 50 kg of the PET chips were discharged from the lower outlet (3) of the water treatment tank while the PET chips were continuously charged into the water treatment tank.
At the same time, withdrawal of the treated water was started at a rate of / hour, and the treated water that had passed through the draining device (4) was returned to the water treatment tank again through the filtration device (5), and was repeatedly used.

After the continuous operation for 72 hours, the Na content of the treated water discharged together with the chips from the outlet is about 0.05 pp.
The content of m and Ca is about 0.1 ppm, and the content of Mg is about 0.1 ppm.
03 ppm, the Si content is about 0.5 ppm, and the Na content of the PET fine obtained at the same time is 0.06 pp.
m, Ca content is 0.07 ppm, Mg content is 0.02 ppm
ppm and Si content were 0.3 ppm. Acetaldehyde content is 3.0ppm, fine content is 40p
pm. Using this PET composition, the above (8)
The density of the top surface of the plug of the hollow container obtained after heating with an infrared heater was 1.375 g / cm ³ without any problem, the haze of the body was 0.7%, and the transparency was excellent. The number of moldings until contamination was 13,000, which was no problem.

(Comparative Example 1) The Na content was about 8.3 pp without using the ion exchange device (9) used in Example 1.
m, Ca content is about 7.3 ppm, Mg content is about 2.5
ppm, the PE content of Example 1 was obtained in the same manner as in Example 1 except that treated water having a Si content of 6.9 ppm was supplied to the water treatment tank.
The T chips were water treated. The obtained PET fine Na
Content is 7.7 ppm, Ca content is 6.9 ppm, M
The g content was 5.5 ppm and the Si content was 10 ppm. The haze of the body of the hollow container obtained in (8) above using this PET was as high as 9.4%.

[0103]

The polyester composition of the present invention is composed of polyester chips and 0.1 to 300 ppm of fine polyester having the same composition as the polyester chips and melted at a temperature of 290 ° C. for 60 minutes. A polyester composition having a cyclic trimer increase of 0.30% by weight or less, wherein the content of sodium in fines of the polyester is N (ppm), the content of calcium is C (ppm), The content of magnesium element is M
(Ppm), when the content of the silicon element is S (ppm), the polyester composition is characterized by satisfying at least one of the following formulas (1) to (4). By using the polyester composition of the above, mold stains during molding are less likely to occur, the crystallization controllability of the plug portion is excellent, and excellent transparency, heat resistance,
A hollow molded article, a sheet-like material, a stretched film, and a packaging material having excellent mechanical properties, residual off-flavor and off-flavor and excellent in fragrance retention. (1) 0.002 ≦ N ≦ 5 (ppm) (2) 0.005 ≦ C ≦ 5 (ppm) (3) 0.005 ≦ M ≦ 5 (ppm) (4) 0.05 ≦ S ≦ 5 ( ppm)

[Brief description of the drawings]

FIG. 1 is an example of a water treatment apparatus used for producing the polyester resin of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 raw material chip supply port 2 overflow discharge port 3 discharge port for polyester chip and treated water 4 drainer 5 fine removal device 6 piping 7 treated water inlet 8 ion exchange water inlet 9 ion exchanger 10 adsorption tower

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[Procedure amendment]

[Submission date] July 10, 2000 (2007.1.
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shutake Kimura 26-21, Akao-cho, Shiga Prefecture (72) Inventor Yoshitaka Eto 248 No. 248 Takashiro, Shiga-cho, Shiga-gun, Shiga Prefecture 20F term (reference) 4F071 AA45 AA46 AB02 AB06 AB09 AD02 AH05 BB05 BB06 BB07 BC01 BC04 4F207 AA24 AB11 AB16 AD27 AG01 AG07 AH55 AH56 KA00 KA17 KF02 4J002 CF04W CF04X CF05W CF05X CF08W CF08X DA066 DA096 GG01 4J029 AA03 CA07 BB01 BA07 CB02 CB10A CC06A CD03 CF15 EA02 EB05A FB07 FC03 FC05 FC08 FC12 FC35 FC36 HA01 HB01 JA061 JA091 JA161 JA253 JB131 JB171 JC033 JC093 JC583 JC751 JE181 JF141 JF181 JF321 JF361 JF471 JF541 JF571 KE02 KE02

Claims (10)

[Claims] 1. A polyester chip and a polyester fine 0.1 having the same composition as the polyester chip.
A polyester composition, comprising -300 ppm and an increase in cyclic trimer of 0.30% by weight or less when melted at a temperature of 290 ° C. for 60 minutes, wherein the content of sodium element in fines of the polyester is Is N (ppm),
The content of calcium element is C (ppm), the content of magnesium element is M (ppm), and the content of silicon element is S
(1) a polyester composition satisfying at least one of the following formulas (1) to (4). (1) 0.002 ≦ N ≦ 5 (ppm) (2) 0.005 ≦ C ≦ 5 (ppm) (3) 0.005 ≦ M ≦ 5 (ppm) (4) 0.05 ≦ S ≦ 5 ( ppm) 2. A polyester obtained mainly using terephthalic acid or its ester-forming derivative or naphthalenedicarboxylic acid or its ester-forming derivative and ethylene glycol as raw materials and using a Ge compound and / or a Ti compound as a catalyst. The polyester composition according to claim 1, which has been subjected to water treatment. 3. The polyester according to claim 1, wherein the polyester is a linear polyester containing at least 90 mol% of ethylene terephthalate as its main repeating unit.
The polyester composition according to item 1. 4. A polyester comprising 90 mol% of ethylene-2,6-naphthalate as its main repeating unit.
The polyester composition according to claim 1, wherein the polyester composition is a linear polyester containing the above. 5. The polyester composition according to claim 1, wherein the polyester chips are obtained by treating polyester chips in a treatment tank with treated water satisfying the following conditions (a) and (b). Polyester composition. (A) Temperature of 40 to 120 ° C (b) Treated water including wastewater from the treatment tank 6. The polyester composition according to claim 1, wherein the polyester chip is treated in a treatment tank with treated water satisfying the following condition (c).
6. The polyester composition according to 5. (C) Treated water having a polyester fine powder content of 1000 ppm or less 7. The polyester composition, wherein a polyester chip is treated in a treatment tank with treated water that satisfies at least one of the following formulas (1) to (4). The polyester composition according to claim 1. (1) 0.001 ≦ N ≦ 1.0 (ppm) (2) 0.001 ≦ C ≦ 0.5 (ppm) (3) 0.001 ≦ M ≦ 0.5 (ppm) (4) 01 ≤ S ≤ 2.0 (ppm) 8. A hollow molded article comprising the polyester composition according to claim 1. 9. A sheet-like product obtained by extruding the polyester composition according to claim 1. 10. A stretched film obtained by stretching the sheet-like material according to claim 9 in at least one direction.