JP2002020469A - Polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester resin which generates little by-product with controlled contamination of a mold during molding and is excellent in transparency. SOLUTION: This polyester resin is 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 polycondensation through esterification or transesterification, wherein the difference between the cyclic trimer content (CTS wt.%) of the resin in the molded material after injection molding at 280 deg.C and the cyclic trimer content (CT0 wt.%) of the resin before injection molding, (CTS-CT0), is at most 0.10 wt.% and wherein the temperature-fall crystallization temperature (TC2) of the resin in the molded material is 180 deg.C or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a process for molding bottles for food and drink, in which the amount of by-products generated during molding is small, mold contamination during molding is suppressed, and transparency is excellent. The present invention relates to a suitable polyester resin.

[0002]

2. Description of the Related Art Conventionally, polyester resins, for example, polyethylene terephthalate resins, are excellent in mechanical strength, chemical stability, gas barrier properties, hygiene properties, etc., and are relatively inexpensive and lightweight. Widely used as packaging containers and the like, especially as food and beverage containers that require heat sterilization filling of mineral water, etc., bottles that have been stretched and heat-set to impart high heat resistance are rapidly growing. It has been shown. These bottles are
For example, it is manufactured by injection-molding a bottomed tubular preform, softening the preform by reheating, and then stretch-blow-molding, by heating a blow mold at that time. The bottles are heat-set to fix the oriented crystals of the molecular chains by stretching and develop heat resistance.

[0003] When a polyester resin produced using an antimony compound, which is the most common in the production of polyester resins, as a polycondensation catalyst, is used as the polyester resin used in the field of food and beverage containers, the resulting molded container is transparent. Properties do not always satisfy the requirements of the market.Also, as a food or beverage container, antimony remaining in the resin elutes from the container at high temperatures such as when filling with heat sterilization or during storage, etc. There are concerns about a slight shift.

[0004] On the other hand, many polyester resins using a germanium compound as a polycondensation catalyst have been proposed. However, when this polyester resin is used, a blow molding die heated for heat setting is easily contaminated. In addition, there is a problem that the surface smoothness of the obtained molded container is impaired, resulting in poor transparency, and that the productivity is greatly deteriorated due to cleaning of the mold.

[0005] On the other hand, the cause of the mold contamination is that by-products such as cyclic trimers are generated in the resin during the injection molding of the preform, and the cyclic trimers and the like are generated in the stretch blow molding. This is considered to be due to migration to the surface of the mold during molding and heat setting. In order to reduce the generation of by-products during injection molding of the preform, for example, Japanese Patent Publication No.
No.-37515 discloses that the resin after polycondensation is 50 to 10%.
A method of deactivating a catalyst in a resin by contacting with hot water of 0 ° 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 article is significantly reduced. Further, it was presumed that the decrease in the transparency was not due to the mold contamination described above, but to the deterioration of the resin itself.

Although many methods using a titanium compound as a polycondensation catalyst have been proposed, the resulting resin has a yellowish color tone, and has a large change in color tone after heating and lacks thermal stability. In contrast, for example, Japanese Patent Application Laid-Open No. 8-73581 discloses a limited amount of a titanium compound, a cobalt compound, and phosphoric acid, phosphorous acid and / or phosphonic acid, or a derivative thereof. A method for producing an achromatic polyester having excellent transparency without using antimony by using a complexing agent is disclosed. However, according to the studies by the present inventors, it has been found that this production method cannot solve the problems of the by-product amount during molding and mold contamination during molding.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has a reduced amount of by-products during molding, suppresses mold contamination during molding, and is transparent. An object of the present invention is to provide a polyester resin having excellent properties.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to achieve the above object, that is, the present invention provides a dicarboxylic acid component containing an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component. And a diol component containing ethylene glycol as a main component, and a polyester resin produced by polycondensation via an esterification reaction or a transesterification reaction, wherein the resin in the molded body after injection molding at 280 ° C. cyclic trimer content (CT _S; wt%) and a cyclic trimer content of the resin before injection molding (C
T _0; with the difference between the weight%) (CT _S -CT ₀₎ is 0.10 wt% or less, the polyester resin crystallization temperature of the resin in the high frequency moldings (T _C2) is 180 ° C. or less, Is the gist.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin of the present invention is obtained by subjecting a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or an ester-forming derivative thereof to a diol component mainly composed of ethylene glycol by an esterification reaction. It is produced by polycondensation via a transesterification reaction.

In the present invention, the aromatic dicarboxylic acid or the ester-forming derivative thereof includes, specifically,
For example, terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4,4′-diphenyl Ketone dicarboxylic acid, 4,
4′-diphenoxyethanedicarboxylic acid, 4,4′-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and dimethyl terephthalate;
Examples thereof include alkyl esters of these aromatic dicarboxylic acids having about 1 to 4 carbon atoms, such as dimethyl 2,6-naphthalenedicarboxylic acid, and halides.

The dicarboxylic acid components other than the aromatic dicarboxylic acids and the ester-forming derivatives thereof include, for example, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and succinic acid and glutaric acid. , Adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, aliphatic dicarboxylic acids such as dodecadicarboxylic acid, and the number of carbon atoms of these alicyclic dicarboxylic acids and aliphatic dicarboxylic acids is 1 to 1
About 4 alkyl esters, halides and the like can be mentioned.

The diol components other than ethylene glycol include, for example, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol,
Aliphatic diols such as ethyl-2-butyl-1,3-propanediol, diethylene glycol, polyethylene glycol and polytetramethylene ether glycol;
1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol,
Alicyclic diols such as 1,4-cyclohexane dimethylol and 2,5-norbornane dimethylol, and xylylene glycol, 4,4′-dihydroxybiphenyl,
2,2-bis (4′-hydroxyphenyl) propane,
Aromatic diols such as 2,2-bis (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid; Examples include an ethylene oxide adduct or a propylene oxide adduct of bis (4′-hydroxyphenyl) propane.

Further, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t- Monofunctional components such as butylbenzoic acid and benzoylbenzoic acid, and trifunctional or higher functionalities such as tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol and pentaerythritol. One or two or more functional components may be used as the copolymer component.

The polyester resin of the present invention contains the aromatic dicarboxylic acid or its ester-forming derivative, preferably terephthalic acid or its ester-forming derivative, in an amount of at least 50 mol%, preferably at least 90 mol% of the dicarboxylic acid component. More preferably, the dicarboxylic acid component accounts for 95 mol% or more, particularly preferably 99 mol% or more, and ethylene glycol to 50 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more of the diol component.
Particularly preferably, it is produced by polycondensing a diol component occupying 97 mol% or more through an esterification reaction or a transesterification reaction. In addition, diethylene glycol by-produced in the reaction system may be copolymerized, and the content of diethylene glycol including the component added from outside the system as a copolymer component is preferably 3 mol% or less.

On the other hand, the polyester resin of the present invention preferably has a cyclic trimer content (CT ₀ ) of 0.50% by weight or less, more preferably 0.40% by weight or less. Exceeding this range tends to cause mold contamination during molding. The acetaldehyde content (AA ₀ ) is 5
It is preferably at most 3 ppm, more preferably at most 3 ppm. Exceeding this range tends to cause problems such as impairing the flavor of the content food and drink when used as a packaging material for food and drink.

The polyester resin of the present invention has an intrinsic viscosity ([η]) of 0.70 dl / [deg.] As measured at 30 [deg.] C. in a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1). g or more.
More preferably, it is 90 dl / g or less.
Particularly preferred is 0.80 dl / g. Further, as a color tone, Lab described in Reference 1 of JIS Z8730 is used.
The color coordinate b of the color difference formula of the Hunter in the color system is preferably 3 or less, more preferably -5 to 2, and particularly preferably -2 to 1.

Further, the polyester resin of the present invention comprises 2
Difference between the cyclic trimer content of the resin in the molded article after injection molding at 80 ° C. (CT _S ; wt%) and the cyclic trimer content of the resin before injection molding (CT ₀ ; wt%) (CT _S -C
T ₀ ) is required to be 0.10% by weight or less,
It is preferably at most 0.05% by weight, more preferably at most 0.03% by weight. This (CT _S -C
If the value of T ₀ ) exceeds the above range, mold contamination during molding will be inferior.

The polyester resin of the present invention has a
The difference (A) between the acetaldehyde content (AA _S ; ppm) of the resin in the molded article after injection molding at 0 ° C. and the acetaldehyde content (AA ₀ ; ppm) of the resin before injection molding.
A _S -AA ₀ ) is preferably 20 ppm or less,
It is more preferably at most 17 ppm, particularly preferably at most 15 ppm. If the value of (AA _S -AA ₀ ) exceeds the above range, problems such as impairing the flavor of the content food and drink when used as a packaging material for food and drink tend to occur.

The polyester resin of the present invention has a
It is essential that the temperature-reducing crystallization temperature (T _C2 ) of the resin in the molded article after the injection molding at 180 ° C. is 180 ° C. or less.
The temperature is preferably 5 ° C. or lower, more preferably 170 ° C. or lower. If the cooling crystallization temperature (T _C2 ) exceeds the above range, the transparency of the molded article will be poor.
Here, the cooling crystallization temperature (T _C2 ) was measured from 20 ° C. to 285 ° C. under a nitrogen stream using a differential scanning calorimeter.
The temperature was increased at a rate of 20 ° C./min, and after maintaining the molten state at 285 ° C. for 5 minutes, the temperature was lowered to 20 ° C. at a rate of 20 ° C./min.
The crystallization peak temperature observed on the way was measured.

The polyester resin of the present invention has a viscosity of 280
The temperature-rise crystallization temperature (T _C1 ) of the resin in the molded article after the injection molding at 150 ° C. is preferably 150 to 180 ° C.
More preferably, the temperature is 55 to 165 ° C.
Particularly preferred is 4 ° C. This elevated crystallization temperature (T
_C1 ) is related to the crystallization speed of the plug portion and the like when the bottle is formed, and the crystallization temperature of the bottle (T _C1 ) is lower than or higher than the above range. The dimensional stability of the plug part is inferior, and there is a tendency that problems such as gas leakage from the plug part and a decrease in scent retention are likely to occur. Here, the temperature rise crystallization temperature (T _C1 ) is observed at a rate of 20 ° C./min from 20 ° C. to 285 ° C. under a nitrogen stream using a differential scanning calorimeter, and observed during the course. The crystallization peak temperature was measured.

In the present invention, the above-mentioned cyclic trimer content (CT _S and CT ₀ ), acetaldehyde content (AA _S and AA ₀ ), falling temperature crystallization temperature (Tc),
The polycondensation of the polyester resin is preferably carried out in the presence of a titanium compound so that the intrinsic viscosity ([η]), the color coordinate b and the like fall within the above ranges. The resin preferably contains the titanium compound.

Here, as the titanium compound, specifically, for example, tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer,
Tetra-t-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, titanium acetate, titanium oxalate, potassium titanium oxalate, titanium sodium oxalate, potassium titanate, sodium titanate, titanium titanate-aluminum hydroxide mixture, chloride Titanium, titanium chloride-aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, ammonium hexafluorotitanate, titanium acetylacetonate, etc. Among them, tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, titanium oxalate and titanium potassium oxalate are preferred.

The polycondensation is carried out in view of its polycondensability, reduction of by-products such as cyclic trimers and acetaldehyde, and transparency and color tone of the obtained resin. Metal compounds, alkaline earth metal compounds,
And at least one metal compound selected from the group consisting of a manganese compound and a manganese compound. The polyester resin of the present invention preferably contains the phosphorus compound, the alkali metal compound, and the alkali metal compound. It is preferable that at least one metal compound selected from the group consisting of an earth metal compound and a manganese compound is contained.

Here, the phosphorus compound includes, for example, orthophosphoric acid, polyphosphoric acid and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, triphenyl phosphate. Zyl phosphate, tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, etc. Pentavalent phosphorus compounds, phosphorous acid, hypophosphorous acid, and
Diethyl phosphite, trisdodecyl phosphite,
Trivalent phosphorus compounds such as tris nonyl decyl phosphite and triphenyl phosphite, and the like, among which orthophosphoric acid, tris (triethylene glycol) phosphate,
Ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate and phosphorous acid are preferred, and tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate and triethylene glycol acid phosphate are particularly preferred.

The alkali metal compound, alkaline earth metal compound and manganese compound are compounds soluble in diols such as ethylene glycol and water, and
For example, lithium, sodium, potassium, magnesium, calcium and the like, oxides, hydroxides, alkoxides, acetates, carbonates, oxalates, and halides, specifically, for example, lithium acetate, sodium acetate, Potassium acetate, magnesium oxide, magnesium hydroxide,
Examples include magnesium alkoxide, magnesium acetate, magnesium carbonate, calcium oxide, calcium hydroxide, calcium acetate, calcium carbonate, manganese oxide, manganese hydroxide, and manganese acetate. Among them, a magnesium compound and a manganese compound are preferable, and a magnesium compound is particularly preferable.

In the present invention, 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, the alkaline earth metal compound, and the manganese compound, The amount used, and the respective contents in the polyester resin associated therewith, were determined based on titanium atoms (T
i) is preferably 0.002 to 1 mol,
More preferably, it is 0.002 to 0.5 mol,
It is particularly preferably from 002 to 0.2 mol. Further, it is preferably 0.02 to 4 mol as a phosphorus atom (P),
It is more preferably 0.02 to 2 mol, and preferably 0.04 to 5 mol as a total (M) of alkali metal atoms, alkaline earth metal atoms and manganese atoms, and 0.04 to 2 mol. More preferably, it is 3 moles.

The titanium compound, the phosphorus compound, an alkali metal compound, an alkaline earth metal compound,
And the amount of each compound of at least one metal compound selected from the group consisting of manganese compounds is a titanium atom (T
i), the phosphorus atom (P), and the total amount (M) of the alkali metal atom, the alkaline earth metal atom, and the manganese atom satisfying the above range, and the phosphorus atom (P) relative to the titanium atom (Ti). ) Has a molar ratio [P / Ti] of 1 or more, more preferably 5 to 50, and especially 15 to 30. The alkali metal atom, the alkaline earth metal atom and the manganese atom with respect to the titanium atom (Ti) The molar ratio [M / Ti] of the total (M) is 2.5 to 250, more preferably 15 to 150,
In particular, those having 25 to 50 are also alkali metal atoms,
Sum of alkaline earth metal atoms and manganese atoms (M)
Molar ratio [P / M] of phosphorus atom (P) with respect to
1, more preferably 0.2-1 and especially 0.4-1
Further, the molar ratio [P / (Ti + M)] of the phosphorus atom (P) to the sum of the titanium atom (Ti) and the total (M) of the alkali metal atom, the alkaline earth metal atom, and the manganese atom is 0.1 to 0.1. 1, more preferably from 0.2 to 1, particularly preferably from 0.4 to 1.

The molar ratio [P / Ti] and the molar ratio [P / Ti
(Ti + M)] is less than the above range, and the molar ratio [M /
Ti] is more than the above range, in any case, the color tone of the obtained resin tends to be yellowish,
Molar ratio [P / M] and molar ratio [P / (Ti + M)]
Is more than the above range, and when the molar ratio [M / Ti] is less than the above range, the polycondensability tends to decrease. When the molar ratio [M / Ti] is less than the above 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 of the phosphorus compound and at least one selected from the group consisting of alkali metal compounds, alkaline earth metal compounds and manganese compounds. It may be made in the coexistence of one kind of metal compound and further in the coexistence of a germanium compound, and accordingly, the polyester resin of the present invention may contain the germanium compound. From the viewpoint of the transparency of the obtained resin, the content is preferably 0.4 mol or less as germanium atom (Ge) per 1 ton of the polyester resin, more preferably 0.3 mol or less. More preferably, it is particularly preferably at most 0.25 mol.

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

In the present invention, the polycondensation may be carried out in the coexistence of a cobalt compound instead of the germanium compound. Accordingly, the polyester resin of the present invention contains the cobalt compound. May be. Incidentally, the content is preferably 1 mol or less, more preferably 0.5 mol or less, as cobalt atom (Co) per 1 ton of the polyester resin.

Here, specific examples of the cobalt compound include cobalt formate, cobalt acetate, cobalt stearate, cobalt oxalate, cobalt carbonate, cobalt bromide, and cobalt acetylacetonate. , Cobalt formate and cobalt acetate are preferred.

In the present invention, at the time of polycondensation, a metal compound other than the above compounds may be present as long as the effects of the present invention are not impaired. Accordingly, the metal compound is contained in the polyester resin of the present invention. It may be contained.
Examples of the metal compound in this case include zirconium, hafnium, chromium, molybdenum, tungsten, iron, nickel, gold, silver, copper, zinc, aluminum, tin, antimony, lanthanum, cerium, and other oxides, hydroxides, alkoxides, Compounds such as carbonates, phosphates, carboxylates, halides and the like can be mentioned.

The polyester resin of the present invention is preferably prepared by subjecting the dicarboxylic acid component containing an aromatic dicarboxylic acid as a main component and a diol component containing ethylene glycol as a main component to an esterification or transesterification reaction, preferably the titanium compound. The polyester resin is produced by polycondensation in the presence of a polyester resin. Basically, a conventional method for producing a polyester resin is used. That is, the dicarboxylic acid component containing the aromatic dicarboxylic acid as a main component and the diol component containing ethylene glycol as a main component are usually mixed in an esterification reaction tank at 240 to 2 parts.
At a temperature of about 80 ° C., usually under a pressure of about 0 to 4 × 10 ⁵ Pa, the esterification reaction is carried out for about 1 to 10 hours under stirring, or after the transesterification reaction in the presence of a transesterification catalyst, The obtained polyester low-molecular weight product as an esterification reaction product or a transesterification reaction product is transferred to a polycondensation tank, and is usually added to the mixture in the presence of the compound.
A melt polycondensation is carried out at a temperature of about 0 to 290 ° C. and gradually from normal pressure to a gradually reduced pressure and finally under reduced pressure of usually about 1333 to 13.3 Pa for about 1 to 20 hours with stirring. Or in a batch mode.

At this time, the preparation of a raw material slurry of a dicarboxylic acid component containing terephthalic acid or an ester-forming derivative thereof as a main component and a diol component containing ethylene glycol as a main component is based on the total diol component relative to the total dicarboxylic acid component. Is preferably in the range of 1.0 to 2.5. Further, the esterification rate of the polyester low molecular weight product as an esterification reaction product or a transesterification reaction product (the ratio of the total carboxyl groups of the raw material dicarboxylic acid component which is esterified by reacting with the diol component)
Is preferably 95% or more. Further, in the case of a transesterification reaction, since it is necessary to use a transesterification catalyst, the transparency of a generally obtained resin tends to be inferior, and therefore, in the present invention, the resin produced through the esterification reaction is used. preferable.

In addition, at the time of polycondensation, the titanium compound, the phosphorus compound, and the alkali metal compound,
The addition of at least one metal compound selected from the group consisting of an alkaline earth metal compound and a manganese compound, or the germanium compound or the cobalt compound to the reaction system requires the use of aromatic dicarboxylic acid and ethylene glycol as raw materials, and May be any of the steps of preparing a slurry with other dicarboxylic acid components and diol components used in accordance with the above, an optional step of an esterification reaction or a transesterification reaction step, or an initial step of a melt polycondensation step. However, as the order of their addition, the phosphorus compound, then the alkali metal compound, the alkaline earth metal compound, and at least one metal compound selected from the group consisting of manganese compounds, or the germanium compound or the cobalt compound And then in the order of the titanium compound It is preferable to that.

As a specific addition step of each compound, particularly in a continuous production method, the phosphorus compound is added in a slurry preparation step, and the phosphorus compound is added from the group consisting of the alkali metal compound, alkaline earth metal compound, and manganese compound. The at least one selected metal compound, or the germanium compound or the cobalt compound, and the titanium compound are preferably added after the esterification reaction or the transesterification step, and the alkali metal compound, the alkali At least one metal compound selected from the group consisting of an earth metal compound and a manganese compound, or the germanium compound or the cobalt compound is added in an esterification or transesterification step, and the titanium compound is formed by an esterification reaction. Material or transesterification Those added polyester transfer pipe or polycondensation tank to the polycondensation vessel of the low molecular weight material as Narubutsu of are particularly preferred.

In general, the resin obtained by melt polycondensation is drawn out in a strand form from a discharge port provided at the bottom of the polycondensation tank, and cut with a cutter with or after cooling with water, and is pelletized into a pellet form. Although it is a granular material such as a chip, the granular material after the melt polycondensation is usually
Under an inert gas atmosphere such as nitrogen, carbon dioxide, and argon,
Or, in a steam atmosphere, or in a steam-containing inert gas atmosphere, usually at a temperature of about 60 to 180 ° C. to crystallize the surface of the resin granules, and then in an inert gas atmosphere, and / or Under a reduced pressure of about 13.3 Pa, usually at a temperature just below the adhesive temperature of the resin to 80 ° C. lower, while flowing the particles so as not to adhere to each other, the heat treatment is usually performed for about 50 hours or less, and the solid phase is solidified. The polycondensation is preferably carried out. By this solid-phase polycondensation, the degree of polymerization can be further increased, and the amount of reaction trimer such as cyclic trimer and acetaldehyde can also be reduced.

Further, the resin obtained by the above-mentioned melt polycondensation or solid-phase polycondensation can be used to improve the thermal stability and to reduce by-products such as cyclic trimers and acetaldehyde during molding. For the purpose, usually, a treatment such as a water treatment of dipping in warm water of 40 ° C. or more for 10 minutes or more, or a steam treatment of contacting with steam or a gas containing steam at 60 ° C. or more for 30 minutes or more may be performed.

Incidentally, the polyester resin of the present invention is obtained by heating the resin to a temperature higher than the crystallization temperature (T
_In order to adjust _C1 ) to the above range, if necessary, a crystalline thermoplastic resin different from the polyester resin is added in an amount of 0.001%.
01-1000 ppm, preferably 0.0005-10
It may be contained at a content of 0 ppm, more preferably 0.001 to 10 ppm, and typical examples of the crystalline thermoplastic resin include a polyolefin resin and a polyamide resin.

Examples of the polyolefin resin include those having 2 to 2 carbon atoms such as ethylene, propylene and butene-1.
About 8 α-olefin homopolymers, those α-olefins, ethylene, propylene, 1-butene,
Methyl-1-butene, 1-pentene, 4-methyl-1-
Other α-olefins having about 2 to 20 carbon atoms such as pentene, 1-hexene, 1-octene, 1-decene, vinyl acetate, acrylic acid, methacrylic acid, acrylate, methacrylate, vinyl chloride, and styrene And the like with a vinyl compound such as, specifically,
For example, ethylene homopolymers such as low / medium / high density polyethylene (branched or linear), ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-4
-Methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer Propylene-based resins such as a copolymer, an ethylene-based resin such as an ethylene-ethyl acrylate copolymer, a propylene homopolymer, a propylene-ethylene copolymer, a propylene-ethylene-1-butene copolymer, and 1-butene alone 1 such as polymer, 1-butene-ethylene copolymer, 1-butene-propylene copolymer
-Butene resins and the like.

Examples of the polyamide resin include polymers of lactams such as butyrolactam, δ-valerolactam, ε-caprolactam, enantholactam, ω-lauryl lactam, 6-aminocaproic acid, 7-aminoheptanoic acid, and the like. Polymers of amino acids such as 8-aminooctanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 1,4-butanediamine, 1,5-pentanediamine, 1,5-hexanediamine Aliphatic diamines such as 1,6-hexanediamine, 1,9-nonanediamine, 1,11-undecadiamine, 1,12-dodecanediamine, α, ω-diaminopolypropylene glycol, 1,3- or 1,4 -Fats such as bis (aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane) Cyclic diamines, 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, cyclohexanedicarboxylic acid, etc. Examples include polycondensates with dicarboxylic acids such as aromatic dicarboxylic acids such as alicyclic dicarboxylic acids, terephthalic acid, and isophthalic acid, and copolymers thereof, and specifically, for example, nylon 4, nylon 6 , Nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 6
10, nylon 611, nylon 612, nylon 6
T, nylon 6I, nylon MXD6, nylon 6/6
6, nylon 6/610, nylon 6/12, nylon 6 / 6T, nylon 6I / 6T and the like.

In the present invention, in order to include the crystalline thermoplastic resin in the polyester resin, the crystalline thermoplastic resin is directly added to the polyester resin so that the content is within the above range, and the mixture is melt-kneaded. In addition to a conventional method such as a method of adding or melting and kneading as a masterbatch, the crystalline thermoplastic resin is mixed with the polyester resin in a production step of the polyester resin, for example, during melt polycondensation (raw material, slurry, catalyst, etc.). ), Immediately after melt polycondensation, immediately after pre-crystallization, during solid phase polycondensation, immediately after solid phase polycondensation, or during the period from the end of the production stage to the molding stage. Either directly added as granules, or a liquid such as water dispersed as granules is brought into contact with a polyester resin chip, or a gas such as air mixed as granules is mixed with polyester. Alternatively, a method of contacting the resin chip-like body, or mixing the polyester resin chip-like body under a flow condition of the polyester resin chip-like body with a member of a crystalline thermoplastic resin, and then melting and kneading the mixture may be used. .
In the latter method, the chip-like body after the melt polycondensation of the polyester resin, at the time of pneumatic transportation to the pre-crystallization machine, or at the time of pneumatic transportation to the solid-phase polycondensation tank, or the chip after solid-phase polycondensation It is preferable to use a method in which a crystalline thermoplastic resin is mixed into the air for pneumatic transportation at the time of pneumatic transportation to the storage tank or to the molding machine.

In the present invention, the polyester resin contains 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 coloring agent, and a filler. Material or the like may be contained.

The polyester resin of the present invention is formed into a preform by, for example, injection molding, followed by stretch blow molding, or blow molding of a parison formed by extrusion molding to form a bottle or the like. Also, after being formed into a sheet by extrusion molding, it is formed into a tray or a 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. It will be. Among them, it is suitable for forming a bottle by a blow molding method of biaxially stretching a preform obtained by injection molding, for example, a liquid seasoning such as carbonated beverage, alcoholic beverage, soy sauce, sauce, mirin, dressing, etc. Further, it is suitably used as a container which requires heat resistance, such as a fruit juice beverage or a beverage such as tea or mineral water, which is subjected to heat setting.

[0046]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 A slurry of 43 kg (260 mol) of terephthalic acid and 19 kg (312 mol) of ethylene glycol was charged in advance with about 50 kg of bis (hydroxyethyl) terephthalate at a temperature of 250 ° C. and a pressure of 1.2 × 10 4. It is supplied sequentially to the esterification reaction tank maintained at ⁵ Pa over 4 hours,
After the end of the supply, the esterification reaction is further performed for 1 hour,
50 kg of this esterification reaction product was transferred to a polycondensation tank.

Subsequently, the polyester obtained by converting ethyl acid phosphate, magnesium acetate and tetra-n-butoxytitanium into ethylene glycol solution, respectively, from the piping to the polycondensation tank to which the esterification reaction product was transferred. 0.840 mol of phosphorus atom (P) and magnesium atom (M) per ton of resin
4.031 mol and 0.1 as titanium atom (Ti).
After successive addition at 5 minute intervals so as to be 021 mol,
The temperature inside the system was raised from 250 ° C. to 280 ° C. over 2 hours and 30 minutes, and the pressure was reduced from normal pressure to 400 Pa in 1 hour to maintain the same pressure.
Melt polycondensation for a time of dl / g, withdrawing in a strand form from an extraction port provided at the bottom of the polycondensation tank,
After cooling with water, cut into chips with a cutter,
kg of polyethylene terephthalate resin (copolymerization amount of diethylene glycol: 2.3 mol%) was produced.

Subsequently, the polyester resin chips obtained above were continuously supplied into a stirring crystallization machine maintained at about 160 ° C. so as to have a residence time of about 5 minutes, and were crystallized. ("IPHH" made by ESPEC
−201 ”) under a nitrogen flow of 40 l / min.
After drying at 60 ° C. for 4 hours, the mixture was heated at 210 ° C. for a period of time at which the intrinsic viscosity became 0.766 dl / g for solid-phase polycondensation.

With respect to the obtained polyester resin chip, the metal atom content, the cyclic trimer content, the acetaldehyde content,
The intrinsic viscosity and the color coordinates b as a color tone were measured, and the results are shown in Table 1.

A metal atom content 2.5 g of a resin sample was ashed by a conventional method in the presence of sulfuric acid, completely decomposed, and made up to a volume of 50 ml with distilled water, and quantified by plasma emission spectroscopy.

A cyclic trimer content (CT ₀ ) resin sample ( 4.0 mg ) was precisely weighed, and a mixed solvent of chloroform / hexafluoroisopropanol (volume ratio: 3/2) was used.
After dissolving in 10 ml, further diluted with 20 ml of chloroform, and precipitated by adding 10 ml of methanol.
Subsequently, the filtrate obtained by filtration is evaporated to dryness, then dissolved in 25 ml of dimethylformamide, and the amount of cyclic trimer (cyclotriethylene terephthalate) in the solution is determined by liquid chromatography (“LC-10A” manufactured by Shimadzu Corporation). ).

An acetaldehyde content (AA ₀ ) resin sample ( 5.0 g ) was precisely weighed, sealed in a 50 ml microvolume cylinder together with 10 ml of pure water under a nitrogen seal,
Heat extraction was performed at 0 ° C. for 2 hours, and the amount of acetaldehyde in the extract was determined by gas chromatography using isobutyl alcohol as an internal standard (“GC-14 manufactured by Shimadzu Corporation”).
A)).

[0054]Intrinsic viscosity ([η]) 0.50 g of the freeze-ground resin sample was added to phenol / tet
In a mixed solvent of lachloroethane (weight ratio 1/1), the concentration
(C) at 1.0 g / dl, at 110 ° C. for 20 minutes
After dissolving, use an Ubbelohde type capillary viscous tube for 30 minutes.
° C, relative viscosity with the stock solution (η_rel) Measure this relative
Viscosity (η_rel) -1 specific viscosity (η _sp) And concentration
(C) ratio (η_sp/ C), and the density (c)
0.5g / dl, 0.2g / dl, 0.1g / dl
The ratio (η_sp/ C)
From these values, the ratio (η) when the concentration (c) is extrapolated to 0
_sp/ C) was determined as the intrinsic viscosity [η] (dl / g).

A color tone resin sample was filled into a cylindrical powder colorimetric cell having an inner diameter of 36 mm and a depth of 15 mm with a scrubber, and was measured using a colorimetric colorimeter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.). , JIS Z
The color coordinates b of the color difference formula of the Hunter in the Lab color system described in Reference 1 of 8730 were obtained as a simple average value of the values measured at four points by rotating the cell by 90 degrees by the reflection method.

Subsequently, the obtained resin was inert
In EVEN (“IPHH-201” manufactured by ESPEC)
And dried at 160 ° C for 4 hours under a nitrogen stream of 40 liters / min.
After drying, an injection molding machine (“M-70A” manufactured by Meiki Seisakusho)
II-DM ”), cylinder temperature 280 ° C, back pressure 5
× 10^FivePa, injection rate 40 cc / sec, holding pressure 35 × 10
^FivePa, mold temperature 25 ° C, molding cycle about 75 seconds,
The shape shown in Fig. 1 is 50 mm long and 100 mm wide,
6 steps with a step of 0.5 mm from 6 mm to 3.5 mm in the direction
A stepped plate with a floor thickness was injection molded. FIG.
In the above, G is a gate portion.

With respect to the obtained molded plate, the content of cyclic trimer, acetaldehyde content, crystallization temperature at lower temperature, crystallization temperature at elevated temperature, and haze as transparency were measured by the following methods. The results are shown in Table 1.

The cyclic trimer content (CT _S ) was measured in the same manner as described above using a sample cut from a 3.5 mm thick tip portion (part A in FIG. 1 ) of a molded plate.

Acetaldehyde Content (AA _S ) The sample was cut into chips of about 4 mm square from a 3.5 mm thick rear end portion (part B in FIG. 1 ) of a molded plate and measured in the same manner as described above.

Cooling crystallization temperature (T _C2 ), heating crystallization temperature
(T _C1 ) A 3.5 mm thick tip part (part A in FIG. 1 ) of the molded plate was cut out, dried at 40 ° C. for 3 days with a vacuum drier, and the sample cut out from the non-surface part was removed. About 10 mg thereof was precisely weighed, and an aluminum open pan and pan cover (normal pressure type, “P / N SSC000E030” and “P / N SS” manufactured by Seiko Denshi Co., Ltd.) were used.
C000E032 ”), and the temperature was increased from 20 ° C. to 285 ° C. at a rate of 20 ° C./min using a differential scanning calorimeter (“ DSC220C ”manufactured by Seiko Co., Ltd.) at 285 ° C. After maintaining the molten state for 20 minutes,
/ Min at a rate of / min, the crystallization peak temperature observed on the way is defined as the cooling crystallization temperature (T _C2 ), and the crystallization peak temperature observed on the way of the temperature increase is the temperature increase crystallization temperature. (T _C1 ).

The thickness of the transparent molded plate is 5.0 mm (C in FIG. 1).
About the haze meter (Nippon Denshoku Co., Ltd. "NDH-3
00A ”).

Examples 2 to 3 A polyester resin was produced in the same manner as in Example 1 except that the amounts of magnesium acetate and tetra-n-butoxytitanium added during the melt polycondensation were changed. amount,
Measure the cyclic trimer content, acetaldehyde content, intrinsic viscosity, color tone, and further injection-mold the stepped molding plate,
Cyclic trimer content, acetaldehyde content, cooling crystallization temperature, heating crystallization temperature, and transparency were measured.
It was shown to.

Further, the obtained polyester resin chip was dried in a vacuum dryer at 130 ° C. for 10 hours, and then, in an injection molding machine (“FE-80S” manufactured by Nissei Plastics Industry Co., Ltd.), at a cylinder temperature of 280 ° C. Back pressure 5 × 10 ⁵ Pa, injection rate 4
5 cc / sec, holding pressure 30 × 10 ⁵ Pa, mold temperature 20
C. and a molding cycle of about 40 seconds, a test-form preform having an outer diameter of 29.0 mm, a height of 165 mm, an average thickness of 3.7 mm and a weight of 60 g was injection-molded. After heating the plug part of the obtained preform by a quartz heater type plug part crystallizer for 180 seconds, a mold pin is inserted to perform crystallization treatment of the plug part. The shape and dimensions were visually observed and evaluated according to the following criteria. The results are shown in Table 1.

The shape and size of the plug portion A : Extremely stable dimensional accuracy is obtained. ；: Stable dimensional accuracy is obtained. X: Insufficient crystallization and buckling in shape.

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, and then charged in a blow mold set at 160 ° C. While stretching in the height direction with a stretching rod, blow molding is performed at a blow pressure of 7 × 10 ⁵ Pa for 1 second, and further at 30 × 10 ⁵ Pa for 40 seconds, heat-set, and air-cooled to obtain an outer diameter of about 95 mm. 500 bottles having a length of about 305 mm, an average body thickness of about 0.37 mm, a weight of about 60 g, and an internal volume of about 1.5 liters are formed, and the surface appearance of the obtained 500th bottle is visually observed to obtain the following. The mold contamination was evaluated based on the standard, and the results are shown in Table 1.

Mold contamination ◎: The surface is smooth and no abnormality is found. ：: The surface smoothness is slightly inferior, but there is no practical problem. ×: The surface becomes rough and rough, and adhesion of foreign matter is also observed.

Examples 4 to 6 The amounts of ethyl acid phosphate and magnesium acetate added during melt polycondensation were changed, and a solution of germanium dioxide in ethylene glycol during the addition of magnesium acetate and tetra-n-butoxytitanium Was added, except that a polyester resin was produced in the same manner as in Example 1, and the metal atom content, cyclic trimer content, acetaldehyde content, intrinsic viscosity, and color tone were measured.
Injection molding the stepped molding plate, cyclic trimer content, acetaldehyde content, cooling crystallization temperature, heating crystallization temperature,
The transparency was measured and the results are shown in Table 1. Example 3
In the same manner as above, the pre-formed body is injection molded and
Evaluate the dimensions, mold the bottle and evaluate the mold contamination,
The results are shown in Table 1.

Example 7 A polyester resin was obtained 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 and treated with water. Manufacture and measure 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 The crystallization temperature, the crystallization temperature, the crystallization temperature, and the transparency were measured. Further, the bottle was molded and the mold contamination was evaluated. The results are shown in Table 1.

Example 8 The procedure of Example 4 was repeated, except that the addition amounts of ethyl acid phosphate and magnesium acetate were changed during the melt polycondensation, and cobalt acetate was used instead of germanium dioxide. Then, a polyester resin is manufactured, and the metal atom content, the cyclic trimer content, the acetaldehyde content, the intrinsic viscosity, and the color tone are measured. Amount, acetaldehyde content, cooling crystallization temperature, heating crystallization temperature, and transparency were measured. The results are shown in Table 1.

Example 9 The polyester resin was obtained 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 and treated with water. Manufacture and measure 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 , The crystallization temperature under cooling, the crystallization temperature under heating, and the transparency were measured. The results are shown in Table 1.

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

Example 10 Using the polyester resin obtained in Example 4, the injection molding of the stepped plate and the injection molding of the preform were carried out.
Example 4 except for adding low-density polyethylene.
The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated, except that the addition amounts were changed using only orthophosphoric acid and germanium dioxide during the melt polycondensation.
The polyester resin is manufactured, and the metal atom content, the cyclic trimer content, the acetaldehyde content, the intrinsic viscosity, and the color tone are measured. Acetaldehyde content, cooling crystallization temperature,
The heated crystallization temperature and the transparency were measured, and the bottle was molded to evaluate the mold contamination. The results are shown in Table 1.

Comparative Example 2 A polyester resin was obtained 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 and treated with water. Manufacture and measure 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 The crystallization temperature, the crystallization temperature, the crystallization temperature, and the transparency were measured. Further, the bottle was molded and the mold contamination was evaluated. The results are shown in Table 1.

Comparative Example 3 A polyester resin was produced in the same manner as in Example 1 except that the addition amount was changed by using ethyl acid phosphate, magnesium acetate, and antimony trioxide during the melt polycondensation. Measure atomic content, cyclic trimer content, acetaldehyde content, intrinsic viscosity, color tone, and further injection-mold a stepped molding plate to obtain cyclic trimer content, acetaldehyde content, cooling crystallization temperature The crystallization temperature and the transparency were measured, and the results are shown in Table 1.

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

According to the present invention, it is possible to provide a polyester resin which generates a small amount of by-products during molding, suppresses mold contamination during molding, and is excellent in transparency.

[Brief description of the drawings]

FIG. 1A is a plan view and FIG. 1B is a front view of a stepped plate for evaluating physical properties formed in Examples.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Nukii 1 Tohocho, Yokkaichi City, Mie Prefecture F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) 4J029 AA03 AB01 AB05 AC01 AC02 AD01 AE01 BA02 BA03 BA04 BA05 BA07 BA08 BA09 BA10 BB06A BB10A BB11A BB12A BB13A BD03A BD04A BD06A BD07A BF09 BH02 CB04A CB05A CB06A CE04 CF06 CF08 CG06 CH06 DB01 DB10 DB11 HA01 HB01 JB01 JA041 JA091 J091 JA093J03F03 J433 J2131 KE05 KF07

Claims (9)

[Claims] 1. A polycondensation of 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 through an esterification reaction or a transesterification reaction. 280 ° C.
And; (wt% CT _S), cyclic trimer content of the resin before injection molding the cyclic trimer content of the resin in the molding body after injection molding at; the difference between (CT ₀ wt%) (CT _S -CT ₀₎
Is 0.10% by weight or less, and the resin has a temperature-reducing crystallization temperature (T _C2 ) of 180 ° C. or less in the molded article. 2. The polyester resin according to claim 1, wherein the resin has a temperature-reducing crystallization temperature (T _C2 ) of 175 ° C. or lower in the molded article after the injection molding at 280 ° C. 3. The polyester resin according to claim 1, wherein a temperature-rise crystallization temperature (T _C1 ) of the resin in the molded article after the injection molding at 280 ° C. is 150 to 180 ° C. 4. Acetaldehyde content (AA _S ; ppm) of a resin in a molded article after injection molding at 280 ° C.
And the acetaldehyde content of the resin before injection molding (AA
₀ ; ppm), and the difference (AA _S -AA ₀ ) is 20 ppm or less. 5. The resin before injection molding has a cyclic trimer content (CT ₀ ) of 0.50% by weight or less, an acetaldehyde content (AA ₀ ) of 5 ppm or less, and an intrinsic viscosity ([η]) of 0.7.
The polyester resin according to any one of claims 1 to 4, which has a color coordinate of 0 to 0.80 dl / g and a color coordinate of b3 or less. 6. Polycondensation in the presence of a titanium compound, wherein the content of the titanium compound is 0.002 to 1 mol as a content of titanium atoms (Ti) per 1 ton of the polyester resin. The polyester resin according to claim 1. 7. A 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, When the content of the compound is 0.02 to 4 mol as phosphorus atoms (P) and 0.1 as total (M) of alkali metal atoms, alkaline earth metal atoms, and manganese atoms, per ton of the polyester resin.
The polyester resin according to claim 6, wherein the amount is from 04 to 5 mol. 8. Polycondensation in the presence of a germanium compound, wherein the content of the germanium compound is
Germanium atom (G) per ton of polyester resin
8. The polyester resin according to claim 6, wherein e) is 0.4 mol or less. 9. The polyester resin according to claim 1, wherein at least 99 mol% of the dicarboxylic acid component is terephthalic acid or an ester-forming derivative thereof, and at least 97 mol% of the diol component is ethylene glycol. .