JP2006199974A - Polyester resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin which is produced by a polycondensation in the presence of at least a titanium compound, little produces by-products, when molded, prevents the staining of molds, when molded, and has excellent transparency. <P>SOLUTION: The polyester resin produced by subjecting a dicarboxylic acid component comprising mainly an aromatic dicarboxylic acid or its ester-forming derivative, and a diol component comprising mainly ethylene glycol to an esterification reaction or an ester interchange reaction, and then polycondensing the reaction product in the presence of at least a titanium compound, is characterized in that a difference (CTs-CTo) is ≤0.10 wt.%, wherein CTs (wt.%) is a resin cyclic trimer content in a molded article after injection-molded at 280°C, and CTo (wt.%) is a resin cyclic trimer content in the resin before injection-molding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyester resin polycondensed in the presence of at least a titanium compound. More specifically, the amount of by-products generated during molding is small, mold contamination during molding is suppressed, and transparency. In particular, the present invention relates to a polyester resin suitable for forming a bottle for food and drink.

  Conventionally, polyester resins, such as polyethylene terephthalate resins, have excellent mechanical strength, chemical stability, gas barrier properties, hygiene, etc., and are relatively inexpensive and lightweight. As a food and drink container that requires heat sterilization filling such as mineral water, bottles that have been given high heat resistance by being stretched and heat-set will exhibit rapid growth. Yes. These bottles are produced, for example, by injection molding a bottomed tubular preform, reheating and softening the preform, followed by stretch blow molding. At that time, the blow mold is heated. In this way, the bottle is heat-set, and the oriented crystals of the molecular chains are stretched by stretching to develop heat resistance.

  And as a polyester resin used in the field of these food and beverage containers, when using a polyester resin produced using a polycondensation catalyst as the most common antimony compound in the production of polyester resin, the antimony remaining in the resin is heated. There are concerns about problems such as elution from a container at a high temperature during sterilization filling or storage and a slight shift to the content food or drink.

  On the other hand, many polyester resins using a germanium compound as a polycondensation catalyst have been proposed. When this polyester resin is used, a blow molding mold heated for heat setting is easily contaminated and obtained. There is a problem that the surface smoothness of the molded container is impaired and the transparency becomes inferior, and the productivity is greatly deteriorated due to the mold cleaning.

  On the other hand, the cause of the mold contamination is that by-products such as a cyclic trimer are generated in the resin during injection molding of the preform, and the cyclic trimer is molded and heated in stretch blow molding. In order to reduce the generation of by-products during injection molding of the preform, for example, Japanese Patent Publication No. 7-37515 discloses a method after polycondensation. A method for deactivating a catalyst in a resin by bringing the resin into contact with hot water at 50 to 100 ° C. is disclosed. However, according to the study by the present inventors, it has been found that this method has a problem that the transparency of the obtained molded product is greatly reduced. Further, it was estimated that the decrease in transparency was not due to the above-mentioned mold contamination but due to the alteration of the resin itself.

Many methods using titanium compounds as polycondensation catalysts have also been proposed. Titanium catalysts are more active than antimony catalysts and germanium catalysts, and can be used in small amounts. There are no concerns about the above, and it is cheaper than germanium-based catalysts, and it is an industrially valuable study subject to produce polyester resins using titanium-based catalysts. In such a case, there is a problem that the obtained resin has a yellowish color tone, and the color tone change after heating is large and lacks in thermal stability. On the other hand, for example, JP-A-8-73581 By using a limited amount of a complexing agent comprising a titanium compound, a cobalt compound, and phosphoric acid, phosphorous acid and / or phosphonic acid or their derivatives. , Process for producing a polyester excellent in transparency achromatic containing no antimony is disclosed. However, according to studies by the present inventors, it has been found that this production method cannot solve the problems such as the amount of by-products during molding and mold contamination during molding.
Japanese Patent Publication No. 7-37515 JP-A-8-73581

  The present invention has been made in view of the above-described prior art, focusing on a method of using a titanium compound as a polycondensation catalyst. The amount of by-products generated during molding is polycondensed in the presence of at least a titanium compound. An object of the present invention is to provide a polyester resin that has a small amount of mold contamination during molding and is excellent in transparency.

The present invention has been made to achieve the above object, that is, the present invention has a dicarboxylic acid component containing an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component and ethylene glycol as a main component. A polyester resin produced by subjecting a diol component to a polycondensation through an esterification reaction or a transesterification reaction in the presence of at least a titanium compound, and the resin cyclic in a molded article after injection molding at 280 ° C. Trimer content (CT _S ; wt%) and cyclic trimer content of resin before injection molding (CT ₀
A polyester resin having a difference (CT _S −CT ₀ ) of 0.10 wt% or less.

  According to the present invention, a polyester resin that is polycondensed in the presence of at least a titanium compound, generates a small amount of by-products during molding, suppresses mold contamination during molding, and has excellent transparency. Can be provided.

  The polyester resin in the present invention comprises at least an esterification reaction or a transesterification reaction between a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol. It is produced by polycondensation in the presence of a titanium compound.

  In the present invention, specific examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalic acid, phenylenedioxydicarboxylic acid, 4 , 4′-diphenyldicarboxylic acid, 4,4′-diphenylether dicarboxylic acid, 4,4′-diphenylketone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, 4,4′-diphenylsulfonedicarboxylic acid, 2, Examples include 6-naphthalenedicarboxylic acid, alkyl esters having about 1 to 4 carbon atoms of these aromatic dicarboxylic acids such as dimethyl terephthalate and dimethyl ester of 2,6-naphthalenedicarboxylic acid, and halides.

  Examples of dicarboxylic acid components other than the aromatic dicarboxylic acid and its ester-forming derivatives include, for example, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and succinic acid, glutaric acid, and adipic acid. , Pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid and other aliphatic dicarboxylic acids, and these alicyclic dicarboxylic acids and aliphatic dicarboxylic acids having about 1 to 4 carbon atoms. Examples thereof include alkyl esters and halides.

  Examples of diol components other than ethylene glycol include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1 1,3-propanediol, diethylene glycol, polyethylene glycol, polytetramethylene ether glycol and other aliphatic diols, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedi Cycloaliphatic diols such as methylol and 2,5-norbornane dimethylol, and xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxy) Diol) propane, 2,2-bis (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and the like, and An ethylene oxide adduct or a propylene oxide adduct of 2,2-bis (4′-hydroxyphenyl) propane may be mentioned.

  Furthermore, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid Monofunctional components such as benzoylbenzoic acid, trifunctional or more polyfunctional components such as tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, 1 type, or 2 or more types may be used as a copolymerization component.

  In the polyester resin of the present invention, the aromatic dicarboxylic acid or an ester-forming derivative thereof, preferably terephthalic acid or an ester-forming derivative thereof is 50 mol% or more, preferably 90 mol% or more, more preferably, of the dicarboxylic acid component. Is 95 mol% or more, particularly preferably 99 mol% or more of the dicarboxylic acid component and ethylene glycol is 50 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, particularly preferably 97 mol% of the diol component. A diol component occupying at least mol% is produced by polycondensation through an esterification reaction or a transesterification reaction. Incidentally, diethylene glycol by-produced in the reaction system may be copolymerized, and the content of diethylene glycol including that added from outside the system as a copolymerization component is preferably 3 mol% or less.

  In the present invention, the polycondensation is carried out in the presence of a titanium compound, and accordingly, the polyester resin of the present invention contains the titanium compound.

  Specific examples of the titanium compound include tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, and tetra-t-butyl. Titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, titanium acetate, titanium oxalate, potassium potassium oxalate, sodium titanium oxalate, potassium titanate, sodium titanate, titanium titanate-aluminum hydroxide mixture, titanium chloride, titanium chloride Aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, ammonium hexafluorotitanate, titanium acetylacetonate, etc. , Tetra -n- propyl titanate, tetra -i- propyl titanate, tetra -n- butyl titanate, titanium oxalate, titanium oxalate potassium are preferred.

  In addition, polycondensation is carried out in terms of polycondensability, reduction of by-products such as cyclic trimer and acetaldehyde, and transparency and color tone of the resulting resin, and phosphorus compounds, alkali metal compounds, It is preferable that at least one metal compound selected from the group consisting of an alkaline earth metal compound and a manganese compound is coexistent, and accordingly, the polyester resin of the present invention includes the phosphorus compound, and It is preferable that at least one metal compound selected from the group consisting of the alkali metal compound, alkaline earth metal compound, and manganese compound is contained.

  Here, specific examples of the phosphorus compound include orthophosphoric acid, polyphosphoric acid, and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, Trivalent (triethylene glycol) phosphate, ethyl diethylphosphonoacetate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, etc. Phosphorus compound, phosphorous acid, hypophosphorous acid, and diethyl phosphite, trisdodecyl phosphite, trisnonyl decyl phosphite, And trivalent phosphorus compounds such as rephenyl phosphite. Among them, orthophosphoric acid, tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate, phosphorous acid are preferable. , Tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate are particularly preferred.

  The alkali metal compound, alkaline earth metal compound, and manganese compound are diols such as ethylene glycol and water-soluble compounds such as lithium, sodium, potassium, magnesium, and calcium. Products, hydroxides, alkoxides, acetates, carbonates, oxalates, halides, etc., specifically, for example, lithium acetate, sodium acetate, potassium acetate, magnesium oxide, magnesium hydroxide, magnesium alkoxide, magnesium acetate , Magnesium carbonate, calcium oxide, calcium hydroxide, calcium acetate, calcium carbonate, manganese oxide, manganese hydroxide, manganese acetate and the like. Among these, a magnesium compound and a manganese compound are preferable, and a magnesium compound is particularly preferable.

  In the present invention, each use amount at the time of polycondensation of the titanium compound, the phosphorus compound, and at least one metal compound selected from the group consisting of the alkali metal compound, alkaline earth metal compound, and manganese compound, And each content in the polyester resin accompanying it is preferably 0.002 to 1 mol, more preferably 0.002 to 0.5 mol as a titanium atom (Ti) per ton of the polyester resin, Particularly preferred is 0.002 to 0.2 mol. The phosphorus atom (P) is preferably 0.02 to 4 mol, more preferably 0.02 to 2 mol, and the total of alkali metal atoms, alkaline earth metal atoms and manganese atoms. (M) is preferably 0.04 to 5 mol, and more preferably 0.04 to 3 mol.

  The amount of each compound of the titanium compound, the phosphorus compound, and at least one metal compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound, and a manganese compound is a titanium atom (Ti). , Phosphorus atoms (P), and the total amount (M) of alkali metal atoms, alkaline earth metal atoms, and manganese atoms satisfying the above range, the phosphorus atoms (P) with respect to titanium atoms (Ti) The molar ratio [P / Ti] is 1 or more, more preferably 5 to 50, particularly 15 to 30, and the total of alkali metal atoms, alkaline earth metal atoms, and manganese atoms with respect to titanium atoms (Ti). The molar ratio [M / Ti] of (M) is 2.5 to 250, more preferably 15 to 150, and particularly 25 to 50. Alkali metal atoms, alkaline earth metal atoms, and man The molar ratio [P / M] of the phosphorus atom (P) to the total amount of manganese atoms (P / M) is more than 0 to 1, more preferably 0.2 to 1, especially 0.4 to 1, and titanium The molar ratio [P / (Ti + M)] of the phosphorus atom (P) to the sum of the atoms (Ti) and the sum (M) of alkali metal atoms, alkaline earth metal atoms, and manganese atoms is 0.1 to 1, and Is preferably 0.2 to 1, particularly 0.4 to 1.

  When the molar ratio [P / Ti] and the molar ratio [P / (Ti + M)] are less than the above range, and the molar ratio [M / Ti] exceeds the above range, the color tone of the obtained resin is On the other hand, the molar ratio [P / M] and the molar ratio [P / (Ti + M)] exceed the above range, and the molar ratio [M / Ti] is less than the above range. In either case, the polycondensation tends to decrease. Moreover, when the molar ratio [M / Ti] is less than the above range and exceeds the range, the color tone tends to deteriorate.

  In the present invention, the polycondensation is carried out in the presence of the titanium compound or at least one selected from the group consisting of the phosphorus compound, an alkali metal compound, an alkaline earth metal compound, and a manganese compound. It may be made in the presence of a metal compound and further in the presence of a germanium compound, and accordingly, the germanium compound may be contained in the polyester resin of the present invention. In view of transparency of the obtained resin, the content thereof is preferably 0.4 mol or less, more preferably 0.3 mol or less as germanium atoms (Ge) per ton of polyester resin. More preferred is 0.25 mol or less.

  Specific examples of the germanium compound include germanium dioxide, germanium tetroxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, germanium tetra-n-butoxide, and the like. Germanium is preferred.

  In the present invention, the polycondensation may be performed in the presence of a cobalt compound instead of the germanium compound, and the polyester resin of the present invention may contain the cobalt compound. Good. In addition, the content is preferably 1 mol or less, more preferably 0.5 mol or less, as a cobalt atom (Co) per ton of polyester resin.

  Specific examples of the cobalt compound include cobalt formate, cobalt acetate, cobalt stearate, cobalt oxalate, cobalt carbonate, cobalt bromide, cobalt acetylacetonate, and the like. Among them, cobalt formate Cobalt acetate is preferred.

  In the present invention, during polycondensation, a metal compound other than the above-mentioned compounds may be present within a range not impairing the effects of the present invention, and accordingly, the polyester resin of the present invention contains the metal compound. May be. Examples of metal compounds in that case include zirconium, hafnium, chromium, molybdenum, tungsten, iron, nickel, gold, silver, copper, zinc, aluminum, tin, antimony, lanthanum, cerium, and other oxides, hydroxides, alkoxides, Examples include carbonates, phosphates, carboxylates, halides, and the like.

The polyester resin of the present invention undergoes an esterification or transesterification reaction between a dicarboxylic acid component having the aromatic dicarboxylic acid as a main component and a diol component having ethylene glycol as a main component, at least in the presence of the titanium compound. Although it is produced by polycondensation, it is basically based on a conventional production method for polyester resins. That is, the dicarboxylic acid component having the aromatic dicarboxylic acid as the main component and the diol component having the ethylene glycol as the main component in the esterification reaction tank are usually at a temperature of about 240 to 280 ° C., usually 0 to 4 × 10 ^5. The esterification reaction is carried out for about 1 to 10 hours under stirring at a pressure of about Pa, or the esterification reaction product or the ester exchange reaction product obtained after the ester exchange reaction in the presence of a transesterification catalyst. The polyester low molecular weight product as a product is transferred to a polycondensation tank, and in the presence of the compound, usually at a temperature of about 250 to 290 ° C. and gradually reduced from normal pressure to about 1333 to 13.3 Pa in the end. In addition, it is carried out by melt polycondensation with stirring for about 1 to 20 hours, and these are carried out continuously or batchwise.

  In this case, the preparation of the raw slurry of the carboxylic acid component having terephthalic acid or its ester-forming derivative as the main component and the diol component having ethylene glycol as the main component is the molar ratio of the total diol component to the total dicarboxylic acid component. Is preferably in the range of 1.0 to 2.5. In addition, the esterification rate of the low molecular weight polyester as an esterification reaction product or transesterification reaction product (ratio of the esterification by reacting with the diol component out of all the carboxyl groups of the raw dicarboxylic acid component) is 95% The above is preferable. In the case of transesterification, since it is generally necessary to use a transesterification catalyst, the transparency of the resin generally obtained tends to be inferior. Therefore, in the present invention, it is produced through an esterification reaction. preferable.

  Further, at the time of polycondensation, the titanium compound, the phosphorus compound, and at least one metal compound selected from the group consisting of the alkali metal compound, alkaline earth metal compound, and manganese compound, or the germanium compound or Addition of cobalt compound to the reaction system is a slurry preparation step, esterification reaction or transesterification step of raw material aromatic dicarboxylic acid and ethylene glycol, and other dicarboxylic acid components and diol components used as necessary The addition order of the phosphorous compound, then the alkali metal compound, the alkaline earth metal compound, and manganese may be any of the following steps: At least one metal compound selected from the group consisting of compounds, or Germanium compound or a cobalt compound, then it is preferred that was made in the order of the titanium compound.

  The specific addition step of each compound was selected from the group consisting of the alkali metal compound, alkaline earth metal compound, and manganese compound, particularly in the continuous production method, in which the phosphorus compound was added in the slurry preparation step. It is preferable that at least one metal compound, or the germanium compound or cobalt compound, and the titanium compound are added after the esterification reaction or transesterification reaction step, and the alkali metal compound or alkaline earth metal. At least one metal compound selected from the group consisting of a compound and a manganese compound, or the germanium compound or cobalt compound is added in an esterification reaction or transesterification step, and the titanium compound is an esterification reaction product or ester. As an exchange reaction product The those that have been added to the transfer pipe or polycondensation tank to the polycondensation vessel of the polyester low molecular weight material is particularly preferred.

  Also, usually, the resin obtained by melt polycondensation is extracted in a strand form from an extraction port provided at the bottom of the polycondensation tank, and is cooled with water or after water cooling, and then cut with a cutter to form pellets, chips, etc. In addition, the granule after the melt polycondensation is usually in an inert gas atmosphere such as nitrogen, carbon dioxide, argon, etc., in a steam atmosphere, or in a steam-containing inert gas atmosphere. In general, after the surface of the resin granule is crystallized by heating at a temperature of about 60 to 180 ° C., the resin is usually adhered in an inert gas atmosphere or / and under a reduced pressure of about 1333 to 13.3 Pa. It is preferable that the solid phase polycondensation is carried out by heat treatment usually for about 50 hours or less while flowing so that the granules do not stick together at a temperature just below 80 ° C. , Together capable of a higher polymerization degree, it is also possible to reduce the cyclic trimer and acetaldehyde reaction by-products.

  Further, the resin obtained by melt polycondensation or solid phase polycondensation as described above is used for the purpose of improving thermal stability and reducing by-products such as cyclic trimer and acetaldehyde during molding. Usually, a treatment such as a water treatment for immersing in warm water of 40 ° C. or higher for 10 minutes or more, or a steam treatment for contacting water vapor of 60 ° C. or higher or a steam-containing gas for 30 minutes or more may be performed.

The polyester resin of the present invention has a cyclic trimer content (CT ₀
) Is preferably 0.50% by weight or less, and more preferably 0.40% by weight or less. If this range is exceeded, mold contamination tends to occur during molding. The acetaldehyde content (AA ₀ ) is preferably 5 ppm or less, more preferably 3 ppm or less. When this range is exceeded, for example, when used as a food and beverage packaging material, problems such as impairing the flavor of the content food and beverage tend to occur.

Further, the polyester resin of the present invention has an intrinsic viscosity ([η]) of 0.70 dl / g or more as a value measured at 30 ° C. in a mixed solvent solution of phenol / tetrachloroethane (weight ratio 1/1). Preferably, it is 0.90 dl / g or less, more preferably 0.70 to 0.80 dl / g. Also, as the color tone, JIS
The color coordinate b of Hunter's color difference formula in the Lab color system described in Reference 1 of Z8730 is preferably 3 or less, more preferably −5 to 2, and −2 to 1. Particularly preferred.

The polyester resin of the present invention has a cyclic trimer content (CT _S ) of the resin in the molded article after injection molding at 280 ° C.
; Weight%) and the difference (CT _S −CT ₀ ) between the cyclic trimer content (CT ₀ ; weight%) of the resin before injection molding.
) Is essential to be 0.10% by weight or less, preferably 0.05% by weight or less, and more preferably 0.03% by weight or less. This (CT _S
If the value of -CT ₀ ) exceeds the above range, the mold contamination during molding is inferior.

In addition, the polyester resin of the present invention has an acetaldehyde content (AA _S ) of the resin in a molded article after injection molding at 280 ° C.
; Ppm) and the difference (AA _S -AA ₀ ) between the acetaldehyde content (AA ₀ ; ppm) of the resin before injection molding.
) Is preferably 20 ppm or less, more preferably 17 ppm or less, and particularly preferably 15 ppm or less. This (AA _S -AA ₀
When the value of) exceeds the above range, for example, when used as a packaging material for food and drink, there is a tendency that problems such as damage to the flavor of the content food and drink are likely to occur.

In the polyester resin of the present invention, the temperature-falling crystallization temperature (T _C2 ) of the molded article after injection molding at 280 ° C. is preferably 180 ° C. or less, more preferably 175 ° C. or less. A temperature of 170 ° C. or lower is particularly preferable. When the temperature-falling crystallization temperature (T _C2 ) exceeds the above range, transparency as a molded product tends to be inferior. Here, the temperature-falling crystallization temperature (T _C2 ) was raised from 20 ° C. to 285 ° C. at a rate of 20 ° C./min using a differential scanning calorimeter and melted at 285 ° C. for 5 minutes. After maintaining the state, the temperature was lowered to 20 ° C. at a rate of 20 ° C./min, and the crystallization peak temperature observed during the measurement was measured.

The polyester resin of the present invention preferably has a resin temperature rising crystallization temperature (T _C1 ) of 150 to 180 ° C., preferably 155 to 165 ° C. in a molded article after injection molding at 280 ° C. More preferably, it is 157-164 degreeC. This temperature rising crystallization temperature (T _C1 ) is related to the crystallization speed of the cap portion or the like when the bottle is formed, and the temperature rising crystallization temperature (T _C1 ) is less than the above range or above the above range. Even in such a case, the dimensional stability of the stopper part as a bottle is inferior, and there is a tendency that problems such as gas leakage from the stopper part and a decrease in fragrance retention tend to occur. Here, the temperature rise crystallization temperature (T _C1 ) was observed at a rate of 20 ° C./min from 20 ° C. to 285 ° C. under a nitrogen stream using a differential scanning calorimeter. The crystallization peak temperature is measured.

In addition, the polyester resin of the present invention is a crystal different from the polyester resin, if necessary, in order to adjust the temperature rising crystallization temperature (T _C1 ) of the resin in the molded article after injection molding to the above range. May be contained in a content of 0.0001 to 1000 ppm, preferably 0.0005 to 100 ppm, more preferably 0.001 to 10 ppm. As the crystalline thermoplastic resin, Examples thereof include polyolefin resins and polyamide resins.

  Examples of the polyolefin resin include homopolymers of α-olefins having about 2 to 8 carbon atoms such as ethylene, propylene, and butene-1, those α-olefins, ethylene, propylene, 1-butene, and 3-methyl. -1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and other α-olefins having about 2 to 20 carbon atoms, vinyl acetate, acrylic acid, Examples thereof include copolymers with vinyl compounds such as methacrylic acid, acrylic acid esters, methacrylic acid esters, vinyl chloride, and styrene. Specifically, for example, low, medium and high density polyethylene (branched or linear) Ethylene homopolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, Len-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer Such as ethylene resins, propylene homopolymers, propylene-ethylene copolymers, propylene-ethylene-1-butene copolymers, and the like, and 1-butene homopolymers, 1-butene-ethylene copolymers Examples thereof include 1-butene-based resins such as coalescence and 1-butene-propylene copolymer.

  Examples of the polyamide resin include polymers of lactams such as butyrolactam, δ-valerolactam, ε-caprolactam, enantolactam, ω-lauryllactam, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-amino. Polymers of amino acids such as octanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 1,4-butanediamine, 1,5-pentanediamine, 1,5-hexanediamine, 1, Aliphatic diamines such as 6-hexanediamine, 1,9-nonanediamine, 1,11-undecadiamine, 1,12-dodecanediamine, α, ω-diaminopolypropylene glycol, 1,3- or 1,4-bis ( Cycloaliphatic diamines such as aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane) , Diamines such as aromatic diamines such as m- or p-xylylenediamine, and aliphatic dicarboxylic acids such as glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and cycloaliphatic dicarboxylic acids Examples thereof include polycondensates with dicarboxylic acids such as aromatic dicarboxylic acids such as dicarboxylic acid, terephthalic acid, and isophthalic acid, or copolymers thereof. Specific examples include nylon 4, nylon 6, nylon 7 and the like. , Nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6/66, nylon 6/610, nylon 6 / 12, nylon 6 / 6T, nylon 6I / 6T, and the like.

  In order to make the polyester resin contain the crystalline thermoplastic resin in the present invention, a method in which the crystalline thermoplastic resin is directly added to the polyester resin and melt-kneaded so that the content falls within the range, Alternatively, in addition to a conventional method such as a method of adding and melting and kneading as a master batch, the crystalline thermoplastic resin is melted at the production stage of the polyester resin, for example, during melt polycondensation (raw material, slurry, catalyst, etc.) Immediately after polycondensation, immediately after pre-crystallization, at the time of solid-phase polycondensation, immediately after solid-phase polycondensation, etc. A liquid such as water that is added directly or dispersed as a granular material is brought into contact with a polyester resin chip-like material, or a gas such as air mixed as a granular material and a polyester resin chip. Or contacting the Jo body, or, after being mixed by a method such as to be in contact with the member of the crystalline thermoplastic resin to flow under the conditions of the polyester resin chips like body can also be by a method in which melt kneading. Among the latter methods, chips after melt polycondensation of the polyester resin, during pneumatic transportation to the pre-crystallization machine, during pneumatic transportation to the solid phase polycondensation tank, or after solid phase polycondensation A method in which a crystalline thermoplastic resin is mixed in the air for pneumatic transportation at the time of pneumatic transportation to the storage tank or pneumatic transportation to the molding machine is preferable.

  In the present invention, the polyester resin includes an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, an antiblocking agent, an antifogging agent, a nucleating agent, a plasticizer, a colorant, a filler, and the like. It may be contained.

  The polyester resin of the present invention is formed into a bottle or the like by, for example, forming it into a preform by injection molding and then performing stretch blow molding or by blow molding a parison formed by extrusion molding. After being formed into a sheet by extrusion molding, it is formed into a tray or container by thermoforming, or the sheet is biaxially stretched into a film or the like, which is particularly useful in the food and beverage packaging field. . Among them, it is suitable for forming a bottle by a blow molding method in which a preform obtained by injection molding is biaxially stretched. For example, liquid seasonings such as carbonated beverages, alcoholic beverages, soy sauce, sauces, mirin, and dressings Furthermore, it is suitably used as a container that requires heat resistance, such as a fruit juice drink, a drink such as tea or mineral water, etc.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
About 50 kg of bis (hydroxyethyl) terephthalate was previously charged in a slurry of 43 kg (260 mol) of terephthalic acid and 19 kg (312 mol) of ethylene glycol, and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa. The esterification reaction tank was sequentially supplied over 4 hours, and after completion of the supply, the esterification reaction was further performed over 1 hour, and 50 kg of the esterification reaction product was transferred to the polycondensation tank.

  Subsequently, to the polycondensation tank to which the esterification reaction product has been transferred, ethyl acid phosphate, magnesium acetate, and tetra-n-butoxytitanium are each obtained as an ethylene glycol solution from the pipe, and 1 ton of polyester resin is obtained. After adding in order of 0.840 mol as a phosphorus atom (P), 4.031 mol as a magnesium atom (M), and 0.021 mol as a titanium atom (Ti), it is added in order at intervals of 5 minutes. The temperature is raised from 250 ° C. to 280 ° C. over 2 hours and 30 minutes, and the inherent viscosity of the resulting resin is 0.55 dl / g while maintaining the same pressure by reducing the pressure from normal pressure to 400 Pa in 1 hour. It is melt-condensed for a period of time, extracted in a strand form from the outlet provided in the bottom of the polycondensation tank, cooled in water, and then cut into chips with a cutter. By were produced approximately 40kg polyethylene terephthalate resin (diethylene glycol copolymerization amount 2.3 mole%).

  Subsequently, the polyester resin chip obtained above was crystallized by continuously feeding it into a stirring crystallizer maintained at about 160 ° C. so that the residence time was about 5 minutes, and an inert oven (ESPEC) (“IPHH-201 type”), dried for 4 hours at 160 ° C. under a nitrogen stream of 40 liters / minute, and then heated at 210 ° C. for a time when the intrinsic viscosity becomes 0.766 dl / g. Condensed.

  About the obtained polyester resin chip | tip, the metal coordinate content in each metal compound, cyclic trimer content, acetaldehyde content, intrinsic viscosity, and the color coordinate b as a color tone are measured by the method shown below, The result is shown. It is shown in Table 1.

A resin sample containing 2.5 g of metal atom content was ashed and completely decomposed in the presence of sulfuric acid, and the volume was adjusted to 50 ml with distilled water, followed by quantification by plasma emission spectrometry.

Cyclic trimer content (CT ₀ )
4.0 mg of a resin sample was precisely weighed and dissolved in 2 ml of a mixed solvent of chloroform / hexafluoroisopropanol (volume ratio 3/2), and further diluted by adding 20 ml of chloroform, and 10 ml of methanol was added thereto for precipitation. The filtrate obtained by subsequent filtration was evaporated to dryness and then dissolved in 25 ml of dimethylformamide, and the amount of cyclic trimer (cyclotriethylene terephthalate) in the solution was measured by liquid chromatography (“LC-10A” manufactured by Shimadzu Corporation). ).

Acetaldehyde content (AA ₀ )
A resin sample (5.0 g) is precisely weighed, sealed in a 50 ml internal volume cylinder with 10 ml of pure water under a nitrogen seal, and heated and extracted at 160 ° C. for 2 hours. The amount of acetaldehyde in the extract is determined by isobutyl alcohol. Was quantified by gas chromatography (“GC-14A” manufactured by Shimadzu Corporation) as an internal standard.

Intrinsic viscosity ([η])
After 0.50 g of the freeze-pulverized resin sample was dissolved in a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1) at a concentration (c) of 1.0 g / dl at 110 ° C. for 20 minutes, Ubbelohde Using a type capillary viscometer, the relative viscosity (η _rel ) with the stock solution is measured at 30 ° C., and this relative viscosity (η _rel
) -1 to determine the ratio (η _sp / c) between the specific viscosity (η _sp ) and the concentration (c) determined from −1, and the concentration (c) is 0.5 g / dl, 0.2 g / dl, 0.1 g. / dl and was even with when seeking respective ratios (eta _sp / c), from these values, the concentration ratio of when the (c) was extrapolated to 0 (η _sp / c) an intrinsic viscosity [eta] ( dl / g).

The color tone resin sample is filled into a cylindrical powder colorimetric cell having an inner diameter of 36 mm and a depth of 15 mm by grinding, and using a colorimetric color difference meter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.), JIS.
The color coordinate b of Hunter's color difference formula in the Lab color system described in Reference 1 of Z8730 was determined by a reflection method as a simple average value of values measured at four locations by rotating the cell by 90 degrees.

Subsequently, the obtained resin was dried in an inert oven (“IPHH-201 type” manufactured by ESPEC) for 4 hours at 160 ° C. under a nitrogen stream of 40 liters / minute, and then an injection molding machine (Meiko Seisakusho Co., Ltd.). “M-70AII-DM”), cylinder temperature 280 ° C., back pressure 5 × 10 ⁵ Pa, injection rate 40 cc / sec, holding pressure 35 × 10 ⁵
Pa, mold temperature of 25 ° C., molding cycle of about 75 seconds, the shape shown in FIG. 1 has a length of 50 mm, a width of 100 mm, and a thickness of 6 steps from 6 mm to 3.5 mm in the horizontal direction. A stepped molded plate was injection molded. In FIG. 1, G is a gate portion.

  With respect to the obtained molded plate, the cyclic trimer content, the acetaldehyde content, the temperature drop crystallization temperature, the temperature rise crystallization temperature, and the haze as transparency were measured by the methods shown below. Indicated.

Cyclic trimer content (CT _S )
Measurement was performed in the same manner as described above using a sample cut out from a tip portion (A portion in FIG. 1) having a thickness of 3.5 mm on the molded plate.

Acetaldehyde content (AA _S )
Measurement was performed in the same manner as described above using a sample cut into a 4 mm square from the rear end portion (B portion in FIG. 1) of the 3.5 mm thick portion of the molded plate.

Temperature drop crystallization temperature ( _TC2 ), temperature rise crystallization temperature ( _TC1 )
After cutting out a tip part (A part in FIG. 1) having a thickness of 3.5 mm in the molded plate and drying it at 40 ° C. for 3 days with a vacuum dryer, using a sample cut out from the non-surface part, about Weigh accurately 10 mg, open pan and pan cover made of aluminum (atmospheric pressure type, “P / N by Seiko Denshi Co., Ltd.)
SSC000E030 ”and“ P / N SSC000E032 ”), and using a differential scanning calorimeter (“ DSC220C ”manufactured by Seiko), the temperature was increased from 20 ° C. to 285 ° C. at a rate of 20 ° C./min. After maintaining the molten state at 285 ° C. for 5 minutes, the temperature is lowered to 20 ° C. at a rate of 20 ° C./minute, and the crystallization peak temperature observed in the middle is defined as the lowered crystallization temperature (T _C2 ). The crystallization peak temperature observed during the temperature increase was defined as the temperature increase crystallization temperature (T _C1 ).

About the thickness 5.0mm part (C part in FIG. 1) in a transparent molded board, haze was measured with the haze meter ("NDH-300A" by Nippon Denshoku Co., Ltd.).

Examples 2-3
A polyester resin was produced in the same manner as in Example 1 except that the addition amounts of magnesium acetate and tetra-n-butoxytitanium during the melt polycondensation were changed, and the metal atom content and cyclic trimer content were produced. Measure the acetaldehyde content, intrinsic viscosity, color tone, and further injection mold the stepped molding plate to determine the cyclic trimer content, acetaldehyde content, temperature drop crystallization temperature, temperature rise crystallization temperature, transparency The results are shown in Table 1.

Furthermore, after drying the obtained polyester resin chip at 130 ° C. for 10 hours with a vacuum dryer, the cylinder temperature was 280 ° C. and the back pressure was 5 with an injection molding machine (“FE-80S” manufactured by Nissei Plastic Industry Co., Ltd.). × 10 ⁵
Pa, injection rate 45 cc / sec, holding pressure 30 × 10 ⁵ Pa, mold temperature 20 ° C., molding cycle about 40 seconds, outer diameter 29.0 mm, height 165 mm, average wall thickness 3.7 mm, weight 60 g A government-shaped preform (preform) was injection molded. After the plug portion of the obtained preform was heated by a quartz heater type plug portion crystallizer for 180 seconds, a mold pin was inserted to perform crystallization treatment of the plug portion. The shape and dimensions were visually observed and evaluated according to the following criteria, and the results are also shown in Table 1.

Mouth part shape, size ◎; is very stable dimensional accuracy is obtained.
○: Stable dimensional accuracy is obtained.
X: Crystallization is insufficient, and the shape is cramped.

The obtained preform was heated in a near-infrared irradiation furnace equipped with a quartz heater for 70 seconds, allowed to stand at room temperature for 25 seconds, then charged into a blow mold set at 160 ° C., and drawn rod While stretching in the height direction with a blow pressure of 7 × 10 ⁵ Pa for 1 second, further 30 × 10 ⁵
By blow molding, heat setting, and air cooling at Pa for 40 seconds, a bottle with an outer diameter of about 95 mm, height of about 305 mm, trunk average thickness of about 0.37 mm, weight of about 60 g, and internal volume of about 1.5 liters The 500th bottle was molded, the surface appearance of the 500th bottle obtained was visually observed, and the mold contamination was evaluated according to the following criteria. The results are also shown in Table 1.

Mold contamination ○: Smooth surface and no abnormality.
Δ: Surface smoothness is slightly inferior.
X: The surface becomes rough and rough, and the adhesion of foreign matter is also observed.

Examples 4-6
Except for changing the addition amount of ethyl acid phosphate and magnesium acetate during melt polycondensation, and adding an ethylene glycol solution of germanium dioxide between the addition of magnesium acetate and tetra-n-butoxytitanium. In the same manner as in Example 1, a polyester resin was produced, and the metal atom content, cyclic trimer content, acetaldehyde content, intrinsic viscosity, and color tone were measured. Then, the cyclic trimer content, acetaldehyde content, temperature drop crystallization temperature, temperature rise crystallization temperature, and transparency were measured, and the results are shown in Table 1. Further, in the same manner as in Example 3, the preform was injection molded to evaluate the shape and size of the stopper portion, the bottle was molded to evaluate the mold contamination, and the results are shown in Table 1.

Example 7
A polyester resin was produced in the same manner as in Example 1 except that the solid phase polycondensation polyester resin obtained in Example 4 was further immersed in distilled water at 95 ° C. for 4 hours for water treatment to produce a metal atom. Content, cyclic trimer content, acetaldehyde content, intrinsic viscosity, color tone, and further injection molding a stepped molding plate, cyclic trimer content, acetaldehyde content, temperature drop crystallization temperature, The temperature rise crystallization temperature and transparency were measured, and further, the bottle was molded to evaluate the mold contamination, and the results are shown in Table 1.

Example 8
A polyester resin was produced in the same manner as in Example 4 except that the addition amounts of ethyl acid phosphate and magnesium acetate during melt polycondensation were changed, and cobalt acetate was used instead of germanium dioxide. The metal atom content, the cyclic trimer content, the acetaldehyde content, the intrinsic viscosity, the color tone are measured, and further, the stepped molding plate is injection-molded, the cyclic trimer content, the acetaldehyde content, The temperature-falling crystallization temperature, the temperature-raising crystallization temperature, and transparency were measured, and the results are shown in Table 1.

Example 9
A polyester resin was produced in the same manner as in Example 5 except that the solid phase polycondensation polyester resin obtained in Example 8 was further immersed in distilled water at 95 ° C. for 4 hours for water treatment. Content, cyclic trimer content, acetaldehyde content, intrinsic viscosity, color tone, and further injection molding a stepped molding plate, cyclic trimer content, acetaldehyde content, temperature drop crystallization temperature, The temperature rise crystallization temperature and transparency were measured, and the results are shown in Table 1.

Example 10
The polyester resin obtained in Example 3 was used in the same manner as in Example 3 except that low density polyethylene was added at the time of injection molding of the stepped molding plate and at the time of injection molding of the preform. The results are shown in Table 1.

Example 10
The polyester resin obtained in Example 4 was used in the same manner as in Example 4 except that low density polyethylene was added at the time of injection molding of the stepped molding plate and at the time of injection molding of the preform. The results are shown in Table 1.

Comparative Example 1
A polyester resin was produced in the same manner as in Example 1 except that the addition amount was changed using only orthophosphoric acid and germanium dioxide during the melt polycondensation, and the metal atom content, cyclic trimer content, Measures acetaldehyde content, intrinsic viscosity, color tone, and further injection molding a stepped molded plate to measure cyclic trimer content, acetaldehyde content, temperature drop crystallization temperature, temperature rise crystallization temperature, and transparency Further, a bottle was molded to evaluate mold contamination, and the results are shown in Table 1.

Comparative Example 2
A polyester resin was produced in the same manner as in Comparative Example 1 except that the solid phase polycondensation polyester resin obtained in Comparative Example 1 was further immersed in distilled water at 95 ° C. for 4 hours for water treatment. Content, cyclic trimer content, acetaldehyde content, intrinsic viscosity, color tone, and further injection molding a stepped molding plate, cyclic trimer content, acetaldehyde content, temperature drop crystallization temperature, The temperature rise crystallization temperature and transparency were measured, and further, the bottle was molded to evaluate the mold contamination, and the results are shown in Table 1.

Reference example 1
A polyester resin was produced in the same manner as in Example 1 except that ethyl acid phosphate, magnesium acetate, and antimony trioxide were used to change the addition amount during melt polycondensation. Measure the content of the monomer, the content of acetaldehyde, the intrinsic viscosity, the color tone, and further, by injection molding a stepped molding plate, the content of the cyclic trimer, the content of acetaldehyde, the temperature-falling crystallization temperature, the temperature-raising crystallization temperature The transparency was measured and the results are shown in Table 1.

(A) of the step-shaped formation board for physical property evaluation shape | molded in the Example is a top view, (b) is a front view.

Claims (9)

A dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol are subjected to an esterification reaction or a transesterification reaction, in the presence of at least a titanium compound. Polyester resin produced by condensation, the cyclic trimer content of the resin (CT _S ; wt%) in the molded article after injection molding at 280 ° C., and the cyclic trimer of the resin before injection molding Body content (CT ₀
A weight percent) difference (CT _S -CT ₀ ) of 0.10 wt% or less. Acetaldehyde content of resin in molded product after injection molding at 280 ° C. (AA _S
; Ppm) and the difference (AA _S -AA ₀ ) between the acetaldehyde content (AA ₀ ; ppm) of the resin before injection molding.
) Is 20 ppm or less. The polyester resin according to claim 1. 3. The polyester resin according to claim 1, wherein the temperature drop crystallization temperature (T _C2 ) of the resin in the molded article after injection molding at 280 ° C. is 180 ° C. or less. The polyester resin according to any one of claims 1 to 3, wherein a temperature increase crystallization temperature (T _C1 ) of the resin in the molded article after injection molding at 280 ° _C is 150 to 180 ° C. Resin before injection molding is cyclic trimer content (CT ₀ ) 0.50 wt% or less, acetaldehyde content (AA ₀ ) 5 ppm or less, intrinsic viscosity ([η]) 0.70 to 0.80 dl / g The polyester resin according to claim 1, which has a color coordinate of b3 or less.   The polyester resin according to any one of claims 1 to 5, wherein the content of the titanium compound is 0.002 to 1 mol as a content of titanium atoms (Ti) per ton of the polyester resin.   The polycondensation in the presence of a phosphorus compound and at least one metal compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound, and a manganese compound, and the content of these compounds is The phosphorus resin (P) is 0.02 to 4 mol, and the total (M) of alkali metal atom, alkaline earth metal atom, and manganese atom is 0.04 to 5 mol per ton of the polyester resin. The polyester resin as described in.   The polyester according to claim 6 or 7, which is polycondensed in the presence of a germanium compound, and the content of the germanium compound is 0.4 mol or less as germanium atoms (Ge) per ton of the polyester resin. resin.   The polyester resin according to any one of claims 1 to 8, wherein 99 mol% or more of the dicarboxylic acid component is terephthalic acid or an ester-forming derivative thereof, and 97 mol% or more of the diol component is ethylene glycol.

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