JP2003221437A - Method of manufacturing polyester resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a polyester resin in high productivity, reducing the contents of acetaldehyde therein and eliminating influence on taste or flavor when it is used as bottle. <P>SOLUTION: On the manufacture of the polyester by esterification of a dicarboxylic acid component comprising terephthalic acid or its ester as the main component and a diol component comprising ethylene glycol as the main component, the method comprises performing polycondensation in the presence of (1) at least one selected from the group consisting of titanium family elements of the 4A family of the periodic table (0.02-0.2 mol), (2) at least one selected from the group consisting of the elements of 1A, 2A family of the periodic table, manganese, iron and cobalt (0.04-0.2 mol) and a phosphorus compound (0.02-0.4 mol). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester which is capable of reducing the content of acetaldehyde as a molded product, eliminates the influence on the flavor and aroma of the contents, and is preferably used for molding bottles of foods and drinks. The present invention relates to a method for producing a resin, and more particularly to a production method having improved polycondensation property.

[0002]

2. Description of the Related Art Conventionally, polyester resins such as polyethylene terephthalate resins are excellent in mechanical strength, chemical stability, gas barrier property, aroma retaining property, hygiene property, and the like.
Since it is relatively inexpensive and lightweight, it is widely used as a packaging container for various foods and drinks, and in particular, bottles with high gas barrier properties, etc. by stretching and heat setting show rapid growth. Has arrived. These bottles are produced, for example, by injection-molding a bottomed tubular preform, reheating the preform to soften it, and then stretch-blow molding, in which case the blow mold is heated. By doing so, the bottle is heat-set, and the oriented crystals of the molecular chains due to stretching are fixed to develop a high gas barrier property and the like.

However, polyethylene terephthalate resins used in the field of packaging containers for foods and drinks are
In a polyethylene terephthalate resin with a polycondensation catalyst of an antimony compound that is widely used for general-purpose bottles, there is a problem that the antimony remaining in the resin elutes from the container at high temperature and slightly transfers to the content food and drink. In polyethylene terephthalate resin with a polycondensation catalyst which is a germanium compound that is often used for heat resistant bottles, there is an unavoidable economic disadvantage because the germanium compound is expensive.
The appearance of polycondensation catalysts to replace them is strongly desired.

On the other hand, many polyethylene terephthalate resins using a titanium compound as a polycondensation catalyst have been proposed, but a large amount of acetaldehyde, a cyclic trimer and the like are by-produced at the time of polycondensation and melt molding, and used as a bottle or the like. When used, there is a problem that the flavor, aroma, etc. of the content food and drink is deteriorated. In contrast, for example, JP-A-8-7
3581 discloses a titanium compound, a cobalt compound,
Also disclosed is a method for producing a polyethylene terephthalate resin having an achromatic color and excellent transparency by using a limited amount of a complexing agent composed of phosphoric acid, phosphorous acid and / or phosphonic acid or derivatives thereof. However,
According to the study by the present inventors, it was found that the polyethylene terephthalate resin obtained by this method could not solve the above-mentioned problem of deterioration of flavor and aroma.

Further, in EP-A-1013692, polycondensation is achieved by using a compound of titanium atom and a metal atom such as magnesium in a specific amount ratio as a polycondensation catalyst. It is disclosed that the by-product of acetaldehyde at the time of molding and melt molding can be suppressed, and the application by the applicant of the present application is JP 2000
No. 339919 discloses (1) a titanium compound, (2) a compound of at least one element selected from the group consisting of a metal element of Group 1A of the periodic table, an element of Group 2A of the periodic table, and manganese; In the polycondensation in the presence of, (3) a phosphorus compound, the order of adding each compound of (1), (2), and (3) to the reaction system is (3), then (2), then A method for producing a polyester resin as (1) is disclosed. However, according to the studies by the present inventors, although these methods are certainly effective in reducing by-products, the disclosed method has room for improvement in terms of polycondensation. found.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and it is possible to reduce the acetaldehyde content as a molded product, so that the flavor of the content when used in a bottle or the like, An object of the present invention is to provide a method for producing a polyester resin which has no influence on scent or the like by improving polycondensation property and productivity.

[0007]

The present invention has been made to achieve the above object, that is, the present invention comprises a dicarboxylic acid component containing terephthalic acid or an ester-forming derivative thereof as a main component, A compound of at least one element selected from the group consisting of (1) titanium group elements of Group 4A of the periodic table through an esterification reaction or a transesterification reaction with a diol component containing ethylene glycol as a main component,
(2) A compound of at least one element selected from the group consisting of a metal element of Group 1A of the periodic table, an element of Group 2A of the periodic table, manganese, iron, and cobalt, and (3) a phosphorus compound,
In the production of a polyester resin by polycondensation in the presence of, the amount of each of the compounds (1), (2), and (3) is adjusted to (1) per 1 ton of the theoretical yield of the polyester resin.
0.02 to 0.2 mol as the total amount of atoms (T) of the compound of (2), and 0.04 to as the total amount (M) of atoms of the compound of (2)
The gist is a method for producing a polyester resin having a content of 0.6 mol and a content of 0.02 to 0.4 mol as a total amount (P) of atoms of the compound (3).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a polyester resin according to the present invention comprises 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 in an esterification reaction. Alternatively, it is produced by polycondensation through an ester exchange reaction.

Here, examples of the ester-forming derivative of terephthalic acid include alkyl esters having about 1 to 4 carbon atoms, and halides. Examples of dicarboxylic acid components other than terephthalic acid or its ester-forming derivative include phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate,
Phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4,4′-diphenylketonedicarboxylic acid,
4,4'-diphenoxyethanedicarboxylic acid, 4,4 '
-Aromatic dicarboxylic acids such as diphenyl sulfone dicarboxylic acid and 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and succinic acid, glutaric acid, adipic acid and pimelic acid , Suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid, and other aliphatic dicarboxylic acids, and alkyl esters having about 1 to 4 carbon atoms, and halides thereof. Among them, isophthalic acid or its ester-forming derivative is preferable in the present invention.

As the diol component other than ethylene glycol, diethylene glycol, which is a by-product in the reaction system, can be cited. As the other diol component, for example,
Trimethylene glycol, tetramethylene glycol,
Aliphatic diols such as pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, polyethylene glycol, polytetramethylene ether glycol, 1 , 2-Cyclohexanediol, 1,4-
Cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, 2,
Alicyclic diols such as 5-norbornane dimethylol, and xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl)
Aromatic diols such as propane, 2,2-bis (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and 2, Two
-Ethylene oxide adduct or propylene oxide adduct of bis (4'-hydroxyphenyl) propane,
Etc.

Further, as a copolymerization component other than the above-mentioned diol component and dicarboxylic acid component, for example, glycolic acid,
Hydroxycarboxylic acids and alkoxycarboxylic acids such as p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, heneicosanol, octacosanol, benzyl alcohol, stearic acid, behenic acid, benzoic acid, t-butylbenzoic acid , Monofunctional components such as benzoylbenzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetetracarboxylic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, sugar ester, etc. A trifunctional or higher polyfunctional component or the like may be used.

The method for producing the polyester resin of the present invention comprises:
At the time of polycondensation, (1) a compound of at least one element selected from the group consisting of titanium group elements of Group 4A of the periodic table, (2)
Amount of each compound of a metal element of Group 1A of the periodic table, an element of Group 2A of the periodic table, a compound of at least one element selected from the group consisting of manganese, iron, and cobalt, and (3) a phosphorus compound Is 0.02 as the total amount (T) of atoms of the compound of (1) per 1 ton of the theoretical yield of polyester resin.
0.2 mol, 0.04 to 0.6 mol as the total amount (M) of atoms of the compound of (2), and 0.02 to 0.4 mol as total amount (P) of the atoms of the compound of (3) It is characterized in that it is present in an amount corresponding to the content of.

Here, (1) as compounds of titanium group elements of Group 4A of the periodic table, that is, titanium, zirconium and hafnium, oxides, hydroxides, alkoxides, acetates, carbonates of these elements, Examples include oxalates and halides. Among the compounds of these elements, a titanium compound is preferable, and 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, etc. obtained by hydrolysis of titanium alkoxide and titanium alkoxide. Titanium oxide, titanium-silicon or zirconium composite oxide obtained by hydrolysis of mixture of titanium alkoxide and silicon alkoxide or zirconium alkoxide, titanium acetate, titanium oxalate, titanium potassium oxalate, sodium titanium oxalate, potassium titanate, titanic acid. Sodium, titanic acid-aluminum hydroxide mixture, titanium chloride, titanium chloride-aluminum chloride mixture, titanium bromide, titanium fluoride, potassium hexafluorotitanate. Hexafluoride titanate cobalt hexafluoride titanate manganese, ammonium hexafluoride titanate, include titanium acetylacetonate and the like, in,
Titanium alkoxides such as tetra-n-propyl titanate, tetra-i-propyl titanate and tetra-n-butyl titanate, titanium oxalate and potassium potassium oxalate are preferable, and tetra-n-butyl titanate is particularly preferable.

Further, (2) the compound of at least one element selected from the group consisting of a metal element of Group 1A of the periodic table, an element of Group 2A of the periodic table, manganese, iron and cobalt is, for example, lithium. , Sodium, potassium, magnesium, calcium, manganese, iron, cobalt and the like, oxides, hydroxides, alkoxides, acetates, carbonates, oxalates, halides and the like, 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,
Examples include ferric acetate, cobalt formate, cobalt acetate, cobalt oxalate, cobalt carbonate, cobalt bromide, and cobalt acetylacetonate. Of these, magnesium compounds are preferable, and magnesium acetate is particularly preferable.

As the phosphorus compound (3), specifically,
For example, orthophosphoric acid, polyphosphoric acid, and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (triethylene glycol) phosphate, methyl acid phosphate, ethyl acid. Phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate,
Pentavalent phosphorus compounds such as phosphoric acid esters such as dioctyl phosphate, triethylene glycol acid phosphate, and phosphorous acid, hypophosphorous acid, and trimethyl phosphite, diethyl phosphite, triethyl phosphite, trisdodecyl phosphite, trisnonyl Decyl phosphite, ethyl diethyl phosphonoacetate,
Examples thereof include phosphite such as triphenyl phosphite, trivalent phosphorus compounds such as metal salts of lithium, sodium, potassium and the like. Among them, phosphoric acid esters of pentavalent phosphorus compounds are preferable, trimethyl phosphate and ethyl acid. Phosphate is particularly preferred.

In the present invention, the above (1) Periodic table No. 4A is used.
It is essential that a compound of at least one element selected from the group consisting of the titanium group elements of the group M is present in an amount of 0.02 to 0.2 mol as the total amount (T) of the atoms, The amount is preferably 0.04 to 0.15 mol. If the total amount (T) of the atoms is less than the above range, both the melt polycondensation property and the solid-phase polycondensation property described below decrease, while if it exceeds the above range, the content of acetaldehyde as a molded product of the obtained resin is decreased. Reduction becomes difficult.

Further, the above (2) metal element of Group 1A of the periodic table,
A compound of at least one element selected from the group consisting of elements of Group 2A of the periodic table, manganese, iron and cobalt,
The total amount (M) of those atoms is required to be present in an amount of 0.04 to 0.6 mol, and 0.05 to 0.6
The content is preferably 0.4 mol, and is preferably 0.
It is more preferable that the amount is 1 to 0.3 mol. If the total amount (M) of the atoms is less than the above range, both the melt polycondensation property and the solid phase polycondensation property which will be described later decrease, while
If the amount exceeds the above range, the solid-phase polycondensation property described below is deteriorated.

It is essential that (3) the phosphorus compound is present in an amount of 0.02 to 0.4 mol as the total amount (P) of atoms per ton of the theoretical yield of polyester resin. , 0.1 to 0.3 mol is preferable. When the total amount (P) of the atoms is less than the above range, it becomes difficult to reduce the content of acetaldehyde in the obtained resin, while when it exceeds the above range, the solid-phase polycondensation property described later is deteriorated.

Further, (1) a compound of at least one element selected from the group consisting of titanium group elements of Group 4A of the periodic table, (2) metal element of Group 1A of the periodic table, Group 2A of the periodic table The amount of each compound of at least one element selected from the group consisting of the element of, the manganese, iron and cobalt, and (3) the phosphorus compound, the total amount of the atoms of the compound of (1) (T) , The total number of atoms (M) of the compound of (2), and (3)
After satisfying the above range as the total amount of atoms (P) of the compound of (1), (3) with respect to the total amount of atoms (T) of the compound of (1)
Ratio (P / T) of the total amount of atoms (P) of the compound of
10 is preferable, 1 to 7 is more preferable, and 2 to 5 is particularly preferable. This ratio (P / T)
When less than the above range, the resulting resin tends to be yellowish and the color tone tends to deteriorate, while when over the above range, both the melt polycondensation property and the solid phase polycondensation property described below tend to decrease.

The ratio (M / T) of the total amount (M) of atoms of the compound (2) to the total amount (T) of atoms of the compound (1) is preferably 0.1-10. It is more preferably 0.5 to 7, and particularly preferably 3 to 5. When this ratio (M / T) is less than the above range, both the melt polycondensation property and the solid phase polycondensation property described below are deteriorated, and it becomes difficult to reduce the acetaldehyde content as a molded product of the obtained resin. On the other hand, when the amount exceeds the above range, the solid-phase polycondensation property described below tends to decrease.

In the present invention, during polycondensation, a metal compound other than each of the above compounds may further be present in the range not impairing the effects of the present invention. In that case, the metal compound may be aluminum, chromium, Compounds such as nickel, copper, zinc, germanium, molybdenum, silver, tin, lanthanum, cerium, tungsten and gold oxides, hydroxides, alkoxides, carbonates, phosphates, carboxylates, halides and the like can be mentioned. . In addition, it is preferable that each of the compounds and the other compounds are soluble in a diol such as ethylene glycol and water.

The method for producing the polyester resin of the present invention comprises:
The 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 are subjected to an esterification reaction or a transesterification reaction to give the above-mentioned (1) Group 4A of the periodic table. A compound of at least one element selected from the group consisting of titanium group elements of (2) a metal element of Group 1A of the periodic table, an element of Group 2A of the periodic table, manganese, iron, and cobalt. A compound of at least one element, and (3)
Polycondensation is carried out in the presence of a phosphorus compound, but basically by a conventional method for producing a polyester resin. That is, the dicarboxylic acid component containing terephthalic acid or an ester-forming derivative thereof as a main component and the diol component containing ethylene glycol as a main component were added to a slurry preparation tank together with a copolymerization component used as necessary. And mixed under stirring to form a raw material slurry, which is obtained by carrying out an esterification reaction in an esterification reaction tank under normal pressure to increased pressure and under heating, or an ester exchange reaction in the presence of an ester exchange catalyst. The low molecular weight polyester as an esterification reaction product or a transesterification reaction product is transferred to a polycondensation tank, and melt polycondensation is performed in the presence of the compound under normal pressure, gradually reduced pressure as reduced pressure, and heating. Let

When the transesterification reaction is carried out using an ester-forming derivative of terephthalic acid as the dicarboxylic acid component, it is usually a titanium compound, a magnesium compound,
Since it is necessary to use a transesterification catalyst such as a calcium compound, a manganese compound and a zinc compound, and it is necessary to use a large amount of the transesterification catalyst, in the present invention, an esterification reaction is performed using terephthalic acid as a dicarboxylic acid component. The method of manufacturing via is preferable.

Here, in the case of the esterification reaction, the raw material slurry is prepared by a carboxylic acid component containing terephthalic acid as a main component, a diol component containing ethylene glycol as a main component, and a copolymerization component used if necessary. And the molar ratio of the diol component to the dicarboxylic acid component is preferably 1.02 to 2.0, more preferably 1.
It is made by mixing as a range of 03 to 1.7.

The esterification reaction is produced by the reaction under the reflux of ethylene glycol using a single esterification reaction tank or a multi-stage reaction apparatus in which a plurality of esterification reaction tanks are connected in series. While removing water and excess ethylene glycol to the outside of the system, the esterification rate (the ratio of those esterified by reacting with the diol component among all the carboxyl groups of the raw material dicarboxylic acid component) is usually 90% or more,
It is preferably performed until it reaches 93% or more. Further, the number average molecular weight of the low molecular weight polyester as an esterification reaction product obtained is preferably from 500 to 5,000.

The reaction conditions in the esterification reaction are usually 240 to 28 in the case of a single esterification reaction tank.
A temperature of about 0 ° C and a relative pressure with respect to the atmospheric pressure are usually
The reaction time is about 1 to 10 hours under stirring with a pressure of about 400 kPa (0 to 4 kg / cm ² G). In the case of a plurality of esterification reaction tanks, the reaction temperature in the first stage esterification reaction tank is usually 240 to 270 ° C, preferably 245 to 265 ° C, and the relative pressure to the atmospheric pressure is usually 5 to 300 kPa. (0.05 to 3 kg / cm ² G), preferably 10 to 200 kPa (0.1 to ² kg / cm ²
G), and the reaction temperature in the final stage is usually 250 to 2
80 ° C., preferably 255 to 275 ° C., relative pressure to atmospheric pressure is usually 0 to 150 kPa (0 to 1.5 kg /
cm ² G), preferably 0 to 130 kPa (0 to 1.3
kg / cm ² G). Incidentally, it is preferable that the esterification rate in each stage is equalized with the increase.

In the esterification reaction, for example, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide,
By adding a small amount of quaternary ammonium hydroxide such as trimethylbenzylammonium hydroxide, basic compounds such as lithium carbonate, sodium carbonate, potassium carbonate, sodium acetate, etc., suppress the by-production of diethylene glycol from ethylene glycol. can do.

Further, the melt polycondensation is performed by a single melt polycondensation tank,
Or, a plurality of melt polycondensation tanks are connected in series, for example,
Using a multi-stage reaction apparatus in which the first stage is a complete mixing type reactor equipped with stirring blades, and the second and third stages are horizontal plug flow type reactors equipped with stirring blades, under reduced pressure , The produced ethylene glycol is distilled out of the system.

As the reaction conditions in the melt polycondensation, in the case of a single polycondensation tank, the temperature is usually about 250 to 290 ° C., the atmospheric pressure is gradually reduced to the atmospheric pressure, and finally the absolute pressure is changed.
Usually 1.3 to 0.013 kPa (10 to 0.1 Tor
The reaction time is about 1 to 20 hours with stirring. In the case of a plurality of polycondensation tanks, the reaction temperature in the first stage polycondensation tank is usually 250 to 290 ° C, preferably 260 to 280 ° C, and the absolute pressure is usually 65 to 1.3.
kPa (500 to 10 Torr), preferably 26 to 2
kPa (200 to 15 Torr), and the reaction temperature in the final stage is usually 265 to 300 ° C., preferably 270.
~ 295 ℃, absolute pressure usually 1.3 ~ 0.013kP
a (10 to 0.1 Torr), preferably 0.65
It is set to 0.065 kPa (5 to 0.5 Torr). As the reaction conditions in the intermediate stage, those intermediate conditions are selected. For example, in a three-stage reactor, the reaction temperature in the second stage is usually 265 to 295 ° C, preferably 2 ° C.
70-285 ℃, absolute pressure usually 6.5-0.13k
Pa (50 to 1 Torr), preferably 4 to 0.26k
Pa (30 to 2 Torr).

Further, at the time of polycondensation, a compound of at least one element selected from the group consisting of the above-mentioned (1) Group 1A titanium element of the periodic table, (2) Metal element of the group 1A periodic table, The compound of at least one element selected from the group consisting of Group 2A elements of the periodic table, manganese, iron and cobalt, and (3) the phosphorus compound are added to the reaction system at the slurry preparation step, the ester It may be at any stage of the esterification reaction or transesterification reaction process, or at the initial stage of the melt polycondensation process, but the compounds of (1) and (2) can be used in the esterification reaction or transesterification reaction process. Alternatively, it is preferably added at the stage of transfer to the melt polycondensation step, and preferably at the stage when the esterification rate of the esterification reaction or transesterification reaction product is 90% or more. The compound of (1) It is preferably added after the compound of 2). The compound (3) is preferably added at the stage where the esterification rate of the esterification reaction or transesterification reaction product is less than 90%.

As a concrete addition process of each compound, for example, the compound (1) is added to the esterification reaction tank at the final stage in the multi-stage reaction apparatus or the esterification reaction or ester at the transfer stage to the melt polycondensation process. In the exchange reaction product,
The compound of (2) is preferably added to the final esterification reaction tank in the multi-stage reaction apparatus. or,
The compound (3) is preferably added to the slurry preparation tank or the first stage esterification reaction tank, and particularly preferably added to the slurry preparation tank. That is, in the present invention,
It is preferable that the order of addition of the compounds of (1), (2), and (3) to the reaction system is (3), then (2), and then (3).

The thermal stability of the resin is improved at the time of melt-molding by improving the thermal stability of the resin by adding the respective compounds of (1), (2) and (3) to the reaction system at the time and order of addition. The by-production of diethylene glycol in the reaction system, which causes by-product such as acetaldehyde, is also suppressed, and the effect of improving melt polycondensation property and solid-phase polycondensation property can be effectively exhibited.

In the polycondensation, the above (1), (2),
And, the addition of each compound of (3) to the reaction system is preferably carried out as a solution of alcohol such as ethylene glycol or water, as an ethylene glycol solution when a titanium compound is used as the compound of (1) above. The titanium atom concentration is 0.01 to 0.3% by weight, and the water concentration is 0.1 to 1% by weight is the dispersibility of the titanium compound in the reaction system and the melt polycondensation property thereof. And from the viewpoint of improving the solid-phase polycondensation property.

The reaction time in melt polycondensation is usually 3.5 hours or less. If the reaction time exceeds that, it tends to be difficult to reduce the acetaldehyde content in the obtained resin and the amount of acetaldehyde by-product during melt molding.

The polyester resin obtained by the melt polycondensation has an intrinsic viscosity ([η ₁ ]) of 3 in a solution of a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1).
As measured at 0 ° C, 0.35 to 0.75 dl / g
Is preferable, and 0.50 to 0.60 dl / g is more preferable. If the intrinsic viscosity ([η ₁ ]) is less than the above range, the extraction property from the polycondensation tank, which will be described later, tends to be poor, while if it exceeds the range, it is difficult to reduce the acetaldehyde content in the obtained resin. It becomes a tendency. Further, the melt polycondensation rate (V ₁ ) as a value obtained by dividing the intrinsic viscosity ([η ₁ ]) of the obtained polyester resin by the reaction time is preferably 0.15 dl / g / hr or more.

The resin obtained by the melt polycondensation is usually extracted in a strand form from an outlet 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. Further, the melt-polycondensed granular material is usually 100 kPa (1 kPa) relative to the atmospheric pressure in an atmosphere of an inert gas such as nitrogen, carbon dioxide or argon.
g / cm ² G) or less, preferably 20 kPa (0.2 k
g / cm ² G) or less, usually for about 5 to 30 hours,
Alternatively, the absolute pressure is usually 6.5 to 0.013 kP
a (50 to 0.1 Torr), preferably 1.3 to 0.
It is preferable to carry out solid phase polycondensation by heating under a reduced pressure of 065 kPa (10 to 0.5 Torr) for usually 1 to 20 hours, usually at 190 to 230 ° C., preferably 195 to 225 ° C. By this solid-phase polycondensation, the degree of polymerization can be further increased and the amount of by-products such as acetaldehyde can be reduced.

At that time, prior to the solid-phase polycondensation, in an inert gas atmosphere, a steam atmosphere or a steam-containing inert gas atmosphere, usually at 120 to 200 ° C., preferably at 130 to 190 ° C., 1 It is preferable to crystallize the surface of the resin granules by heating for about 4 minutes to 4 hours.

Polyester obtained by solid phase polycondensation
Resin has an intrinsic viscosity ([η₂]) Is phenol / teto
3 with a solution of a mixed solvent of lachloroethane (weight ratio 1/1)
As a value measured at 0 ° C, 0.70 to 0.90 dl / g
Is preferably 0.71 to 0.85 dl / g
Is more preferably 0.72-0.80 dl / g
Is particularly preferable. Intrinsic viscosity ((η₂]) Is the above range
If less than, the mechanical strength as a molded product such as a bottle is insufficient.
On the other hand, when the above range is exceeded, during melt molding
It is difficult to suppress by-products such as acetaldehyde
It will be a direction. Also, the intrinsic viscosity of the obtained solid-phase polycondensation resin is
((Η₂]) And the intrinsic viscosity of the melt polycondensation resin
((Η₁])) ((Η₂]-[Η₁]) The above reaction
Solid-phase polycondensation rate as a value divided by time (V₂) Is
It is preferably 0.008 to 0.015 dl / g / hr.
Good Also, this solid phase polycondensation relative to the melt polycondensation rate
Speed ratio (V ₂/ V₁) Is in the range of 0.04 to 0.07
Is preferable, and is in the range of 0.05 to 0.07.
Is more preferable.

Further, the resin obtained by the melt polycondensation or the solid-phase polycondensation as described above is usually treated with water by immersing it in warm water of 40 ° C. or higher for 10 minutes or more, or steam or steam of 60 ° C. or higher. A treatment such as steam treatment in which the contained gas is contacted for 30 minutes or more, or treatment with an organic solvent, treatment with an acidic aqueous solution of various mineral acids, organic acids, phosphoric acid, or the like, Group 1A metal, Group 2A The catalyst used for polycondensation can also be deactivated by treatment with an alkaline aqueous solution of a group metal or amine or an organic solvent solution.

In the polyester resin obtained by the production method of the present invention, the terephthalic acid component accounts for 97 mol% or more of the total dicarboxylic acid component, and the dicarboxylic acid component other than terephthalic acid accounts for 3 mol% or less of the total dicarboxylic acid component. It is preferably a polycondensate, more preferably a polycondensate in which isophthalic acid accounts for 0.1 to 3 mol% of the total dicarboxylic acid component, and a polycondensate in which isophthalic acid accounts for 1 to 2 mol%. It is particularly preferable to have. When isophthalic acid is in this range, the solid-phase polycondensation rate tends to be high, and it tends to be easy to reduce the acetaldehyde content of the resulting resin as a molded product. Further, it is preferable that the ethylene glycol component occupies 97 mol% or more of the total diol component and the diol component other than ethylene glycol is 3 mol% or less of the total diol component, and diethylene glycol is 1 to 1% of the total diol component. A polycondensate of 3 mol% is particularly preferable. If the amount of diethylene glycol exceeds this range, there is a tendency that problems such as deterioration in gas barrier properties when the obtained resin is used as a molded product and difficulty in reducing the acetaldehyde content occur. Further, the copolymerization component such as a dicarboxylic acid component other than terephthalic acid and ethylene glycol and a diol component is preferably 6 mol% or less with respect to the total dicarboxylic acid component,
It is more preferably 4.5 mol%.

The polyester resin obtained by the production method of the present invention has, as described above, (1) Periodic Table No. 4A
A compound of at least one element selected from the group consisting of titanium group elements of the Group, (2) a metal element of Group 1A of the periodic table,
It is polycondensed in the presence of a compound of at least one element selected from the group consisting of Group 2A elements of the periodic table, manganese, iron and cobalt, and (3) a phosphorus compound. , (1), (2), and (3) as the total amount (T) of atoms of the compound of (1) per ton of the theoretical yield of the polyester resin, 0.02 to 0.2 mol, ( The total amount (M) of atoms of the compound of 2) is 0.04 to 0.6 mol, and the total amount (P) of atoms of the compound of (3) is 0.
02 to 0.4 mol, respectively, and
The ratio (P / T) of the total amount of atoms (P) of the compound of (3) to the total amount of atoms (T) of the compound of (1) is 0.1 to 10, and (1) is also included. The ratio (M / T) of the total amount (M) of atoms of the compound (2) to the total amount (T) of atoms of the compound (4) is preferably 0.1 to 10.

The polyester resin obtained by the production method of the present invention has an acetaldehyde content of 5.0 pp.
It is preferably m or less, more preferably 3.0 ppm or less. The acetaldehyde content in the molded product after injection molding at 280 ° C. is preferably 20 ppm or less, more preferably 18 ppm or less, particularly preferably 15 ppm or less. If the acetaldehyde content exceeds the above range, it tends to be difficult to eliminate the influence on the flavor, aroma and the like of the content as a molded product such as a bottle.

The polyester resin obtained by the production method of the present invention preferably has a cyclic trimer content of not more than 0.60% by weight, more preferably not more than 0.50% by weight. When the cyclic trimer content exceeds the above range,
The mold tends to be contaminated during molding of a bottle or the like, and the transparency of the molded body tends to deteriorate.

As the color tone, the color coordinate b value of the Hunter color difference formula in the Lab color system described in Reference 1 of JIS Z8730 is preferably 4 or less, more preferably 3 or less. If the b value exceeds the above range, the color tone of the molded product such as a bottle tends to be yellowish.
In order to set the color coordinate b value within the above range, a so-called toning agent may be added, and examples of the toning agent include Solvent Blue 104, Solvent Red 135, Pigment Blue 29, and 15: 1, the same 15: 3, Pigment Red 187, the same 263, Pigment Violet 19
And the like.

The haze of the molded product having a thickness of 5 mm after injection molding at 280 ° C. is preferably 10% or less, more preferably 8% or less.

The polyester resin obtained in the present invention is formed, for example, by injection molding, followed by stretch blow molding, or by blow molding a parison molded by extrusion molding.
Molded into a bottle or the like, or molded into a sheet by extrusion molding, and then molded into a tray or a container by thermoforming, or biaxially stretched the sheet into a film or the like,
In particular, it becomes useful as a packaging material for food and drink. Among them, it is suitable for molding a bottle by a blow molding method in which a preform obtained by injection molding is biaxially stretched, and for example, a liquid seasoning such as a carbonated drink, an alcoholic drink, a soy sauce, a sauce, mirin, and a dressing. Further, it is preferably used as a container for beverages such as fruit juice drinks, vitamin drinks, flavor teas, and mineral water after heat setting.

[0047]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 A continuous slurry preparation tank, a two-stage esterification reaction tank connected in series thereto, and a three-stage melt polycondensation tank connected in series to the second-stage esterification reaction tank Using a polymerization apparatus, terephthalic acid and ethylene glycol were continuously supplied to the slurry preparation tank at a weight ratio of 865: 485, and a 0.3 wt% ethylene glycol solution of ethyl acid phosphate was added to the produced polyester resin 1 Content as phosphorus atom (P) per ton is 0.194
A slurry is prepared by continuously adding and stirring and mixing the resulting mixture in a molar amount, and the slurry is prepared under a nitrogen atmosphere at 260 ° C. and a relative pressure of 50 kPa (0.5 kg / cm 2).
² G), the first stage esterification reaction tank set to an average residence time of 4 hours, then 260 ° C. under a nitrogen atmosphere, a relative pressure of 5 kPa (0.05 kg / cm ² G), an average residence time of 1. The esterification reaction was carried out by continuously transferring to the second stage esterification reaction tank set for 5 hours. At that time, the average esterification rate measured by the following method was 85% in the first stage and 9% in the second stage.
It was 5%.

<Average Esterification Rate> Samples were deuterated chloroform / hexafluoroisopropanol (weight ratio 7
/ 3) of a solution dissolved in a mixed solvent of 3% by weight, a nuclear magnetic resonance apparatus ("JNM-EX2" manufactured by JEOL Ltd.).
70 type "), ¹ H-NMR is measured, each peak is assigned, the amount of terminal carboxyl groups (A mol / ton of sample) is calculated from the integrated value of the peak, and the terephthalic acid unit of the terephthalic acid unit is calculated by the following formula. The esterification rate (E%) as a ratio of the esterified ester of all the carboxyl groups was calculated. Esterification rate (E) = [1-A / {(1000000 /
192.2) × 2}] × 100

At this time, a 0.6% by weight solution of magnesium acetate tetrahydrate in ethylene glycol was added as magnesium atoms (Mg) per ton of the produced polyester resin through the upper pipe provided in the second stage. Amount 0.2
It was continuously added in an amount of 47 mol.

Subsequently, when the esterification reaction product obtained above is transferred to a melt polycondensation tank, tetrabutyl titanate is added to the esterification reaction product in the transfer pipe at a titanium atom concentration of 0.15. % By weight, water content of 0.
As an ethylene glycol solution having a concentration of 5% by weight, the content of titanium atoms (Ti) per ton of the produced polyester resin was 0.063 mol continuously, while continuously adding it at 270 ° C. and an absolute pressure of 2.6 kPa ( 20 Torr)
1st stage melt polycondensation tank set to, then 278
C., second stage melt polycondensation tank set to absolute pressure 0.5 kPa (4 Torr), then third stage melt polycondensation tank set to 280 ° C., absolute pressure 0.3 kPa (2 Torr) Continuously transferred to the polycondensation tank, the residence time in each polycondensation tank was adjusted so that the intrinsic viscosity ([η ₁ ]) of the obtained polyester resin was 0.56 dl / g.
Melt polycondensation is performed for 17 hours, and it is withdrawn in a strand form from an outlet provided at the bottom of the polycondensation tank, and after water cooling,
A polyester resin was produced by cutting with a cutter into chip-like particles.

Subsequently, the polyester resin chips obtained above were crystallized by continuously supplying them to a stirring crystallization machine maintained at about 160 ° C. under a nitrogen atmosphere so that the residence time was about 60 minutes. Then, the mixture was continuously supplied to a tower type solid-state polycondensation apparatus, and the intrinsic viscosity ([η ₂ ]) of the obtained polyester resin was 0.75 d at 205 ° C. in a nitrogen atmosphere.
Solid phase polycondensation was carried out by adjusting the residence time so as to be 1 / g and heating for 19 hours. Incidentally, the intrinsic viscosity of the melt polycondensation resin ([eta _1]) and solid phase intrinsic viscosity of polycondensation resin ([eta _2]) were measured by the following methods.

<Intrinsic Viscosity> Freeze-pulverized resin sample 0.2
5 g of phenol / tetrachloroethane (weight ratio 1 /
After dissolving in the mixed solvent of 1) at a concentration (c) of 1.0 g / dl at 110 ° C. for 30 minutes in the case of a melt polycondensation resin and at 120 ° C. for 30 minutes in the case of a solid polycondensation resin Using an Ubbelohde-type capillary viscous tube, the relative viscosity (η _rel ) with the stock solution was measured at 30 ° C., and this relative viscosity (η
The ratio (η _sp / c) of the specific viscosity (η _sp ) and the concentration (c) obtained from _rel ) -1 was calculated, and the concentration (c) was 0.5 g /
The respective ratios (η _sp / c) were also obtained for dl, 0.2 g / dl and 0.1 g / dl, and the ratio (η _sp ) when the concentration (c) was extrapolated to 0 was calculated from these values. _sp / c) was determined as the intrinsic viscosity [η] (dl / g).

Further, the intrinsic viscosity of the melt polycondensation resin
((Η₁]) Melt as a value divided by the melt polycondensation time
Polycondensation rate (V₁), The intrinsic viscosity of the solid-phase polycondensation resin
Degree ((η ₂] And the intrinsic viscosity of the melt polycondensation resin ([η
₁])) ((Η₂]-[Η₁]) Is the solid phase polycondensation time
Solid-phase polycondensation rate (V₂) And melt
Fusion polycondensation rate (V₁Solid phase polycondensation rate (V₂)
Ratio of (V₂/ V₁) Are calculated respectively, and the results are shown in Table 1.
Indicated.

Further, in the obtained solid-phase polycondensation resin chip, each titanium atom (Ti), magnesium atom (Mg), and phosphorus atom (P) of titanium component, magnesium component, and phosphorus component per ton of resin is obtained. Was measured by the method shown below, and the results are shown in Table 1.

<Metal Atom Content> 2.5 g of resin sample
After ashing with hydrogen peroxide in the presence of sulfuric acid by a conventional method and completely decomposing, the volume was adjusted to 50 ml with distilled water. A plasma emission spectrophotometer (IC manufactured by JOBIN YVON
P-AES "JY46P type") and quantified, and converted to the molar amount in 1 ton of polyester resin.

Further, the solid phase polycondensation resin chips obtained were measured for the diethylene glycol copolymerization amount, the acetaldehyde content, the cyclic trimer content, and the color coordinate b value as the color tone by the following method, and the results Is shown in Table 1.

<Content of Copolymerization Component> Nuclear magnetic resonance of a solution prepared by dissolving a resin sample in a mixed solvent of deuterated chloroform / hexafluoroisopropanol (weight ratio 7/3) to a concentration of 3% by weight. Using a device ("JNM-EX270" manufactured by JEOL Ltd.), ¹ H-NMR was measured, each peak was assigned, and the content of the copolymerization component was calculated from the integrated value of the peak.

<Acetaldehyde content> Resin sample 5.
Precisely weigh 0 g, seal it in a micro cylinder with an internal volume of 50 ml together with pure water 10 ml under a nitrogen seal, and perform heat extraction at 160 ° C. for 2 hours. The amount of acetaldehyde in the extract is isobutyl alcohol as an internal standard. It quantified using gas chromatography (Shimadzu "GC-14A").

<Content of cyclic trimer> 200 mg of resin sample
Was precisely weighed and dissolved in 2 ml of a mixed solvent of chloroform / hexafluoroisopropanol (volume ratio 3/2).
Further, 20 ml of chloroform was added to dilute the mixture, 10 ml of methanol was added thereto to reprecipitate, and the filtrate obtained by filtration was evaporated to dryness. The residue was diluted with dimethylformamide 25.
After dissolving in ml, the amount of cyclic trimer (cyclotriethylene terephthalate) in the solution was quantified using liquid chromatography (“LC-10A” manufactured by Shimadzu Corporation).

<Color Tone> The resin sample was filled in a cylindrical powder color measuring cell having an inner diameter of 30 mm and a depth of 12 mm, and a colorimetric color difference meter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.) was used. ,
The color coordinate b value of the Hunter color difference formula in the Lab color system described in Reference 1 of JIS Z8730 was obtained as a simple average value of values measured at four points by rotating the measurement cell by 90 degrees by the reflection method.

Subsequently, the obtained resin was placed in an inert oven ("IPHH-201 type" manufactured by ESPEC Co., Ltd.).
After drying at 160 ° C. for 4 hours under a nitrogen stream of 40 liters / minute, an injection molding machine (“M-70AII manufactured by Meiki Seisakusho Co., Ltd.”) was used.
-DM "), cylinder temperature 280 ° C, back pressure 5 × 1
0 ⁵ Pa, injection rate 40 cc / sec, holding pressure 35 × 10 ⁵ P
a, the mold temperature is 25 ° C., the molding cycle is about 75 seconds, and the shape shown in FIG. 1 has a length of 50 mm, a width of 100 mm, and a six-step thickness of 0.5 mm in the lateral direction from 6 mm to 3.5 mm. The stepped plate was injection molded. In addition, in FIG. 1, G is a gate part.

With respect to the obtained molded plate, the acetaldehyde content and haze were measured by the methods described below, and the results are shown in Table 1. <Acetaldehyde content> Thickness of molded plate 3.5
The sample was cut out from the rear end portion of the mm portion (B portion in FIG. 1) into a chip of about 4 mm square, and chips were used, and the measurement was performed in the same manner as above. <Haze> The thickness 5.0 mm portion (C portion in FIG. 1) of the molded plate was measured using a haze meter (“NDH-300A” manufactured by Nippon Denshoku Co., Ltd.).

Separately, the obtained polyester resin chips were dried in a vacuum dryer at 130 ° C. for 10 hours, and then in an injection molding machine (“FE-80S” manufactured by NISSEI PLASTIC INDUSTRIES 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
A test tube-shaped preform (preform) having an outer diameter of 29.0 mm, a height of 165 mm, an average wall thickness of 3.7 mm and a weight of 60 g was injection-molded at 40 ° C. for a molding cycle of about 40 seconds.

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, charged into a blow mold set at 130 ° C., and stretched. While stretching in the height direction with a rod, blow molding at 7 × 10 ⁵ Pa for 1 second, further at 30 × 10 ⁵ Pa for 5 seconds, blow molding, heat setting, and air cooling,
A bottle having an outer diameter of about 95 mm, a height of about 305 mm, an average wall thickness of about 0.35 mm, a weight of about 60 g, and an internal volume of about 1.5 liter was molded.

The obtained bottle was evaluated for acetaldehyde odor by the following method, and the results are shown in Table 1. <Bottle acetaldehyde odor> After the bottle was heated in the oven at 50 ° C for 1 hour, the acetaldehyde odor was subjected to a sensory test, and 5 (extremely low acetaldehyde odor) to 1
(Evaluation of acetaldehyde odor enough to get on the nose) was evaluated in 5 levels.

Examples 2 to 9, Comparative Examples 1 to 9 Copolymerization component and its amount, addition amount and order of addition of phosphorus compound, magnesium compound and titanium compound, titanium atom concentration and water content of titanium compound in ethylene glycol solution A polyester resin chip was produced in the same manner as in Example 1 except that the concentration, and the melt polycondensation time and the solid-phase polycondensation time were changed as shown in Table 1. Shown in 1. In Comparative Example 7, phosphorous acid was used instead of ethyl acid phosphate, and cobalt acetate tetrahydrate was used instead of magnesium acetate tetrahydrate.
Titanium potassium oxalate was used instead of tetrabutyl titanate, titanium potassium oxalate, cobalt acetate tetrahydrate and phosphorous acid were added in this order, and in Comparative Example 9, ethyl orthophosphate was used instead of ethyl acid phosphate. Tetrabutyl titanate, magnesium acetate tetrahydrate and orthophosphoric acid were added in this order.

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

EFFECTS OF THE INVENTION According to the present invention, the content of acetaldehyde as a molded article can be reduced, and thus the polyester resin, which has no influence on the flavor and aroma of the content when used in a bottle, is polycondensed. It is possible to provide a method for producing a product with improved productivity and improved productivity.

[Brief description of drawings]

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

Continued front page    (72) Inventor Masahiro Nukui             1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation             Inside the company F-term (reference) 4J029 AA03 AB04 AE01 BA03 BA10                       BB03 BB10 BB12A BC03A                       BC07A BH07 CB04A CB05A                       CB06A CB10A CC06A DB13                       EA03 EB05 JC413 JC453                       JC593 JF021 JF031 JF041                       JF131 JF141 JF321 JF331                       JF341 JF541 JF561 JF571                       KB04 KB05 KB24 KB25 KE05

Claims (7)

[Claims] 1. 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 are subjected to an esterification reaction or a transesterification reaction to give (1) the periodic table. At least 1 selected from the group consisting of elements of Group 4A titanium group
A compound of one element, (2) a metal element of Group 1A of the periodic table, an element of Group 2A of the periodic table, a compound of at least one element selected from the group consisting of manganese, iron, and cobalt, and (3 ) In producing a polyester resin by polycondensation in the presence of a phosphorus compound, the amount of each of the compounds (1), (2), and (3) is adjusted to (1 ) 0.02 to 0.2 mol as the total amount of atoms (T) of the compound, 0.04 to 0.6 mol as the total amount (M) of atoms of the compound of (2), and the compound of (3) A method for producing a polyester resin, wherein the total amount of atoms (P) is 0.02 to 0.4 mol. 2. The ratio (P / T) of the total amount (P) of atoms of the compound of (3) to the total amount (T) of atoms of the compound of (1) is 0.1 to 10. Manufacturing method of polyester resin. 3. The ratio (M / T) of the total amount (M) of atoms of the compound of (2) to the total amount (T) of atoms of the compound of (1) is 0.1 to 10. The method for producing a polyester resin according to 1. 4. The order of adding each compound of (1), (2), and (3) to the reaction system is (3), then (2), and then (1). The method for producing a polyester resin according to any one of claims. 5. The compound of (1) is a titanium compound,
The method for producing a polyester resin according to claim 1, wherein the compound (2) is a magnesium compound and the compound (3) is a phosphoric acid ester. 6. The method according to claim 5, wherein the titanium compound is added to the reaction system as an ethylene glycol solution having a titanium atom concentration of 0.01 to 0.3% by weight and a water concentration of 0.1 to 1% by weight. A method for producing the described polyester resin. 7. 0.1 to 3 with respect to all dicarboxylic acid components
The method for producing a polyester resin according to claim 1, wherein mol% of isophthalic acid or an ester-forming derivative thereof is used.