JP2000239367A - Production of copolyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a copolyester resin by stably performing the copolymerization of a dicarboxylic acid component to impart an excellent color tone and a good gas barrier property to the copolyester, whereby the polyester resin having a stable quality can be produced. SOLUTION: This method for producing a copolyester resin comprises subjecting a dicarboxylic acid component containing terephthalic acid or its ester-forming derivative as a main component and phenylenedioxydiacetic acid as a comonomer and a diol component containing ethylene glycol as a main component to an esterification reaction or a transesterification reaction and then polycondensing the product. Therein, the phenylenedioxydiacetic acid is added to the reaction system in the presence of the esterification reaction product or transesterification reaction product of the diol component with the dicarboxylic acid component excluding the phenylenedioxydiacetic acid and then carrying out the polycondensation reaction after five minutes or longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copolymerized polyester resin obtained by copolymerizing a dicarboxylic acid component for imparting gas barrier properties, and more particularly to a method for imparting gas barrier properties with excellent color tone. The present invention relates to a method for producing a copolymerized polyester resin capable of stably performing copolymerization of a dicarboxylic acid component and thus producing a polyester resin of stable quality.

[0002]

2. Description of the Related Art Conventionally, polyester resins represented by polyethylene terephthalate resins have attracted attention in terms of excellent transparency, gas barrier properties, safety and health, and the like, in addition to excellent mechanical properties and chemical properties. Injection molded preforms as stretch blow molded bottles, or extruded sheets as thermoformed trays or cups,
Alternatively, as a film or the like obtained by biaxially stretching the sheet, remarkable growth has been exhibited, particularly in the field of food packaging.

[0003] However, although the gas barrier properties of polyester resins are superior to those of polyolefin resins and polystyrene resins commonly used in the field of food packaging, for example, the barrier properties of oxygen gas, carbon dioxide gas and the like are particularly strictly required. However, such a bottle is not always sufficient for carbonated beverages, alcoholic beverages, and the like, and the tendency is particularly remarkable in recent miniaturized bottles.

On the other hand, for example, as a method for improving the gas barrier properties of polyethylene terephthalate resin, Japanese Patent Application Laid-Open No.
No. 01060, JP-A-5-186570 and the like,
A method of copolymerizing a dicarboxylic acid component containing terephthalic acid or an ester-forming derivative thereof as a main component and phenylenedioxydiacetic acid as a copolymer component, and a diol component containing ethylene glycol as a main component is disclosed. At the start of the esterification reaction or ester exchange reaction between the ester-forming derivative and ethylene glycol, phenylenedioxydiacetic acid is added in advance to cause an esterification reaction or a transesterification reaction, followed by polycondensation, or terephthalic acid or an ester thereof. It describes a copolymerization method in which phenylenedioxydiacetic acid is added to an esterification reaction product or a transesterification reaction product between a formed derivative and ethylene glycol, followed by polycondensation.

However, according to the studies by the present inventors, according to the method of adding phenylenedioxydiacetic acid described in these publications, the obtained copolymerized polyester resin has a slightly yellowish color and is inferior in color tone. It was found that the copolymerization could not be carried out stably, so that a polyester resin of stable quality could not be produced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has excellent color tone and can stably carry out copolymerization of a dicarboxylic acid component for imparting gas barrier properties. Accordingly, it is an object of the present invention to provide a method for producing a copolymerized polyester resin capable of producing a polyester resin of stable quality.

[0007]

The present invention has been made to achieve the above object, that is, the present invention comprises terephthalic acid or an ester-forming derivative thereof as a main component and phenylenedioxydiacetic acid. In producing a copolymerized polyester resin by polycondensing a dicarboxylic acid component as a copolymer component and a diol component containing ethylene glycol as a main component through an esterification reaction or a transesterification reaction, phenylenedioxydiacetic acid is used. Is added in the presence of an esterification reaction product or a transesterification reaction product of the dicarboxylic acid component and the diol component excluding phenylenedioxydiacetic acid, and after 5 minutes or more from the addition, the polycondensation reaction And a method for producing a copolymerized polyester resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a copolymerized polyester resin of the present invention, terephthalic acid or its alkyl (about 1 to 4 carbon) ester-forming derivative is mainly used as a dicarboxylic acid component, and ethylene is used as a diol component. Glycol is the main component. Here, specific examples of the ester-forming derivative include dimethyl terephthalate and diethyl terephthalate.

In the present invention, the ethylene terephthalate unit comprising terephthalic acid or its ester-forming derivative as a dicarboxylic acid component and ethylene glycol as a diol component preferably accounts for at least 80 mol% of the constituent repeating units. More preferably, it accounts for at least mol%. 80 ethylene terephthalate units
If it is less than mol%, the mechanical properties and heat resistance of the copolymerized polyester resin tend to be poor.

In the present invention, phenylenedioxydiacetic acid is essential as a copolymerization component in the dicarboxylic acid component, and the ratio of the phenylenedioxydiacetic acid to the total dicarboxylic acid component is 0.1 to 20 mol%. Is preferably 0.2 to 10 mol%, more preferably 0.5 to 5 mol%.

Incidentally, phenylenedioxydiacetic acid includes
Specifically, for example, 1,2-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, 1,4-phenylenedioxydiacetic acid, 2-methyl-1,3-phenylenedioxydiacetic acid , 5-methyl-1,3-phenylenedioxydiacetic acid, 6-methyl-1,3-phenylenedioxydiacetic acid, 5-ethyl-1,3-phenylenedioxydiacetic acid, 6-ethyl-1,3 -Phenylenedioxydiacetic acid, 5-methoxy-1,3-phenylenedioxydiacetic acid, 6-methoxy-1,3-phenylenedioxydiacetic acid, 4-chloro-1,2-phenylenedioxydiacetic acid,
4-chloro-1,3-phenylenedioxydiacetic acid and the like, and ester-forming derivatives thereof, and the like.
1,3-phenylenedioxydiacetic acid and its ester-forming derivatives are preferred.

Further, as terephthalic acid and its ester-forming derivative, and dicarboxylic acid components other than phenylenedioxydiacetic acid, for example, phthalic acid, isophthalic acid, 4,4
Aromatic dicarboxylic acids such as 4'-diphenyldicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid , Hexahydroterephthalic acid, alicyclic dicarboxylic acids such as hexahydroisophthalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as diglycolic acid, or ester-forming derivatives thereof One or more diol components other than ethylene glycol include, for example, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol. Aliphatic diols such as recall,
Alicyclic diols such as 1,2-cyclohexanediol, 1,1-cyclohexanedimethylol, and 1,4-cyclohexanedimethylol, pyrocatechol, resorcinol, hydroquinone, 4,4′-dihydroxybiphenyl, 2,2-bis ( Aromatic such as 4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid One or more diols may be further used, for example, glycolic acid, p-hydroxybenzoic acid,
hydroxycarboxylic acids and alkoxycarboxylic acids such as p-β-hydroxyethoxybenzoic acid; monofunctional components such as stearic acid, stearyl alcohol, benzyl alcohol, benzoic acid, t-butylbenzoic acid, and benzoylbenzoic acid; trimellitic acid One or two or more trifunctional or higher polyfunctional components such as trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, glycerol, and pentaerythritol may be used as a copolymer component. The dicarboxylic acid component is preferably isophthalic acid, and the diol component is preferably diethylene glycol, 1,4-cyclohexane dimethylol. These are all dicarboxylic acid components,
Preferably within 10 mol%, based on all diol components,
More preferably, it is used in a range of 5 mol% or less.

The method for producing a copolymerized polyester resin of the present invention is basically a method of preparing a polyester resin comprising a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol. According to a conventional manufacturing method. That is, a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component are esterified in an esterification reaction tank, and the obtained esterification reaction product is transferred to a polycondensation reaction tank and subjected to polycondensation. In the direct polymerization method, a transesterification reaction is carried out in a transesterification reaction between a dicarboxylic acid component having an ester-forming derivative of terephthalic acid as a main component and a diol component having ethylene glycol as a main component in an esterification reaction tank. A transesterification method in which polycondensation is carried out by transferring to a polycondensation reaction tank, or a slurry prepared by dispersing a dicarboxylic acid component containing terephthalic acid as a main component in a diol component containing ethylene glycol as a main component in a slurry preparation tank, To the esterification reaction product or transesterification reaction product obtained above in the esterification reaction tank. A continuous direct polymerization method in which the reaction product obtained is continuously added and esterified under normal pressure, and the obtained reaction product is continuously or / and stepwise transferred to the polycondensation reaction tank and polycondensed is used. Can be taken. Also, usually, the resin obtained by the polycondensation reaction,
The polycondensation reaction tank is drawn out in a strand form from a discharge port provided at the bottom of the polycondensation reaction tank, and is cut into a pellet shape with a cutter while cooling with water or after cooling with water. By performing the solid phase polymerization, the degree of polymerization can be further increased, and acetaldehyde, low molecular oligomer, and the like, which are reaction by-products, can also be reduced.

In the above production method, the esterification reaction may be carried out, if necessary, for example, by using diantimony trioxide,
200 to 270 in the presence of an esterification catalyst such as an organic acid salt such as antimony, titanium, magnesium and calcium.
C. and a pressure of about 0 to 3 kg / cm ² G. The transesterification reaction may be carried out, if necessary, for example, using an organic acid salt such as lithium, sodium, potassium, magnesium, calcium, manganese, titanium, zinc or the like. In the presence of a transesterification catalyst such as
The polycondensation reaction is carried out at a pressure of about 3 kg / cm ² G. The polycondensation reaction is carried out by using a metal oxide such as germanium dioxide, germanium tetroxide, or diantimony trioxide, or an organic material such as germanium, antimony, zinc, titanium, or cobalt. At a temperature of about 240 to 290 ° C. in the presence of a polycondensation catalyst such as an acid salt, and a stabilizer such as orthophosphoric acid, phosphorous acid, and alkyl phosphoric acid;
It is performed under reduced pressure of about 0.1 to 10 mmHg. In the solid-phase polymerization, pre-crystallization is performed by heating at a temperature of about 120 to 200 ° C. for 1 minute or more, and then 180 to 240 ° C.
It is performed at a temperature of about ° C., in an atmosphere of an inert gas such as nitrogen gas, and / or under a reduced pressure of about 0.1 to 10 mmHg.

In the method for producing a polyester resin according to the present invention, phenylenedioxydiacetic acid as a copolymerization component in the dicarboxylic acid component is converted into an esterification reaction product of a dicarboxylic acid component excluding phenylenedioxydiacetic acid with a diol component or It is essential to carry out the polycondensation reaction at least 5 minutes after the addition, in addition to the addition of the transesterification reaction product, whereby the color tone is excellent and the copolymerization can be carried out stably. Therefore, it is possible to produce a stable quality polyester resin.

Here, adding phenylenedioxydiacetic acid in the presence of an esterification reaction product or a transesterification reaction product means that the reaction system in which the esterification reaction product or the transesterification reaction product is present. Is not particularly limited, and specifically, for example, in an esterification reaction tank during an esterification reaction or a transesterification reaction, or an esterification reaction product after the completion of the esterification reaction or the transesterification reaction. Or to the transesterification reaction product, to the esterification reaction tank, or to the transfer pipe during transfer from the esterification reaction tank to the polycondensation reaction tank, or to the polycondensation tank after transfer, etc. Method. In, for the esterification reaction product or transesterification reaction product after completion of the esterification reaction or transesterification reaction, to the transfer pipe during transfer from the esterification reaction tank to the polycondensation reaction tank, or after transfer Is preferably added to the polycondensation tank.

The form of the phenylenedioxydiacetic acid in the above-mentioned addition in the presence of the esterification reaction product or the transesterification reaction product may be in the form of a powder or a heated melt. It is preferable to add phenylenedioxydiacetic acid as a slurry obtained by dispersing phenylenedioxydiacetic acid in a diol component, preferably ethylene glycol, in a preparation tank.

In the present invention, after the addition of phenylenedioxydiacetic acid in the presence of an esterification reaction product or a transesterification reaction product, a polycondensation reaction is carried out after 5 minutes or more. However, it is preferable that the time is not less than 40 minutes after the lapse of 10 minutes or more.

The polyester resin obtained by the production method of the present invention generally has an intrinsic viscosity of 0.55 to 1.5.
dl / g, preferably 0.65-1.2 dl / g, particularly preferably 0.75-0.95 dl / g,
Further, as the color tone, the color coordinate b value (which serves as a guideline of yellowish / bluish) in the Lab color system defined in Reference 1 of JIS Z8730 is preferably −3 to +6, more preferably −2 to +5. And particularly preferably -1 to +4.

The polyester resin obtained by the production method of the present invention is formed into a preform by, for example, injection molding and then stretch blow-molded.
Alternatively, the parison formed by extrusion molding is formed into a bottle or the like by blow molding, or formed into a sheet by extrusion molding, and then 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 field of food packaging.

Among them, the preform obtained by injection molding is suitable for forming a bottle by a blow molding method such as a cold parison method in which the preform is biaxially stretched after reheating. For example, carbonated drinks, fruit juice drinks, It is suitably used as a container for alcoholic beverages, beverages such as tea and mineral water, and liquid seasonings such as soy sauce, sauces, mirin, and dressings.

[0022]

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 50.5 kg (260 mol) of dimethyl terephthalate and 32.3 kg (520 mol) of ethylene glycol were charged into an esterification reactor and dissolved, and manganese acetate dissolved in ethylene glycol was added to a polyester resin. After performing the transesterification while distilling off the generated methanol while maintaining the temperature at about 220 ° C. while maintaining the temperature at about 220 ° C.
43.2 kg of terephthalic acid (2
60 mol) and 19.4 kg of ethylene glycol (312
Mol) in a slurry preparation tank,
The mixture was continuously transferred over a period of time, an esterification reaction was performed at about 250 ° C., and 4 hours after the transfer, 50% of the reaction solution was transferred to a polycondensation reaction tank.

Subsequently, 1.82 kg (8 mol) of 1,3-phenylenedioxydiacetic acid and 3.99 kg (64 mol) of ethylene glycol were slurried in the polycondensation reaction tank into which the esterification reaction product was transferred. The slurry slurried in the preparation tank (of which 1,3-phenylenedioxydiacetic acid was equivalent to 3 mol% based on the total dicarboxylic acid component) was transferred over 10 minutes, and after 15 minutes, the polycondensation catalyst was transferred. Diantimony trioxide dissolved in ethylene glycol as 300 pp with respect to the theoretical yield of the polyester resin
m, cobalt acetate also dissolved in ethylene glycol, 90 ppm based on the theoretical yield of the polyester resin
After adding normal phosphoric acid dissolved in ethylene glycol as a stabilizer in an amount of 180 ppm with respect to the theoretical yield of the polyester resin, about 250 minutes over about 100 minutes. ℃ to about 270
The polycondensation reaction was carried out for 3 hours after the start of the pressure reduction while the ethylene glycol was being distilled off while the temperature was raised to 0 ° C. and the pressure was reduced from the normal pressure to 1 mmHg. , And after cooling with water, pelletized with a cutter to produce a copolymerized polyester resin.

The same operation as described above was repeated three more times, and the content of 1,3-phenylenedioxydiacetic acid and the intrinsic viscosity of each polyester resin produced under the same conditions a total of four times were determined by the following methods. , And color tone were measured, and the results are shown in Table 1 (in the table, 1,3-phenylenedioxydiacetic acid is abbreviated as “PDDA”).

A sample of the resin solution containing 1,3-phenylenedioxydiacetic acid was analyzed by nuclear magnetic resonance (NMR) for 1H.
Was analyzed to determine the mole% of 1,3-phenylenedioxydiacetic acid based on the total carboxylic acid component.

About 0.25 g of an intrinsic viscosity resin sample was phenol / 1,1,2,2
-About 2 mixed solvents of tetrachloroethane (weight ratio 1/1)
After dissolving at 110 ° C. so as to be 1.0% by weight in 5 ml, the solution was cooled to 30 ° C. and measured with a fully automatic solution viscometer (“2CH DJ504” manufactured by Chuo Rika Co., Ltd.).

A color tone resin sample was prepared by measuring the bottom diameter to about 30 mm and the height to about 12 m.
m, and filled in a cylindrical powder colorimetric cell using a color difference meter (“ND-300A” manufactured by Nippon Denshoku Industries Co., Ltd.).
The color coordinate b value in the Lab color system defined in Reference 1 of 8730 is obtained by rotating the cell by about 90 degrees by the reflection method.
It was determined as a simple average of the values measured at the points.

Further, after blending the four kinds of resins obtained by the above polycondensation, solid-state polymerization was carried out at a temperature of 205 ° C. and a reduced pressure of 1 mmHg or less for 20 hours. The intrinsic viscosity of the obtained resin was 0.81 dl / g.

Example 2 A slurry of 1,3-phenylenedioxydiacetic acid and ethylene glycol was supplied to a pipe which was transferring an esterification reaction product to a polycondensation reaction tank, and an ester containing the slurry was used. Except that the polycondensation catalyst and the stabilizer were added and the polycondensation reaction was started 6 minutes after the transfer of the polymerization reaction product to the polycondensation reaction tank was completed, except that A copolymerized polyester resin was manufactured, and the content, intrinsic viscosity, and color tone of 1,3-phenylenedioxydiacetic acid were measured in the same manner, and the results are shown in Table 1. The intrinsic viscosity of the resin subjected to solid-state polymerization in the same manner as in Example 1 was 0.80 dl / g.

Comparative Example 1 A polycondensation catalyst and a stabilizer were added immediately after the transfer of a slurry of 1,3-phenylenedioxydiacetic acid and ethylene glycol to the polycondensation reaction tank to start the polycondensation reaction. Prepared a copolymerized polyester resin in the same manner as in Example 1, and the content, intrinsic viscosity, and color tone of 1,3-phenylenedioxydiacetic acid were measured in the same manner, and the results are shown in Table 1.

Comparative Example 2 A slurry of 1,3-phenylenedioxydiacetic acid and ethylene glycol was previously transferred to a polycondensation reaction tank, and then the esterification reaction product was transferred to the polycondensation reaction tank. 15 minutes after the transfer of the product to the polycondensation reaction tank, a polycondensation catalyst was added in the same manner as in Example 1 except that the polycondensation catalyst and stabilizer were added and the polycondensation reaction was started. Was prepared, and the content, intrinsic viscosity, and color tone of 1,3-phenylenedioxydiacetic acid were measured in the same manner, and the results are shown in Table 1.

Comparative Example 3 1.82 kg (8 mol) of 1,3-phenylenedioxydiacetic acid was melted at about 220 ° C. in a dissolving tank, and the melt was transferred to the esterification reaction product. It was transferred to a polycondensation reaction tank (1,3-phenylenedioxydiacetic acid was equivalent to 3 mol% based on all dicarboxylic acid components), and a polycondensation catalyst and a stabilizer were added immediately after the transfer to perform polycondensation. Except that the reaction was started, a copolymerized polyester resin was produced in the same manner as in Example 1 and 1,3-
The phenylenedioxydiacetic acid content, intrinsic viscosity, and color tone were measured, and the results are shown in Table 1.

[0034]

[Table 1]

[0035]

According to the present invention, the color tone is excellent,
It is possible to stably copolymerize a dicarboxylic acid component for imparting gas barrier properties, and to provide a method for producing a copolymerized polyester resin capable of producing a polyester resin of stable quality.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Norio Kobe 1 Tohocho, Yokkaichi-shi, Mie F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) KB13 KB22 KE02 KE03

Claims (5)

[Claims] 1. An esterification reaction or esterification of a dicarboxylic acid component containing terephthalic acid or an ester-forming derivative thereof as a main component and phenylenedioxydiacetic acid as a copolymer component, and a diol component containing ethylene glycol as a main component. In producing a copolymerized polyester resin by polycondensation via an exchange reaction, phenylenedioxydiacetic acid is converted to an esterification reaction product or transesterification of the dicarboxylic acid component and the diol component except phenylenedioxydiacetic acid. A method for producing a copolymerized polyester resin, comprising adding to the presence of a reaction product and conducting a polycondensation reaction after 5 minutes or more from the addition. 2. The method for producing a copolymerized polyester resin according to claim 1, wherein phenylenedioxydiacetic acid is added as a slurry dispersed in a diol component. 3. The method for producing a copolymerized polyester resin according to claim 2, wherein the diol component in the slurry in which phenylenedioxydiacetic acid is dispersed is ethylene glycol. 4. The method for producing a copolymerized polyester resin according to claim 1, wherein the ratio of phenylenedioxydiacetic acid to the total dicarboxylic acid component is 0.1 to 20 mol%. 5. The method according to claim 1, wherein the phenylenedioxydiacetic acid is 1,3-phenylenedioxydiacetic acid.