JP6408108B2 - Beverage container - Google Patents

Description

  The present invention relates to a polyethylene terephthalate resin pellet suitable for obtaining a molded article that is easily plasticized and excellent in heat resistance, a method for producing the same, and a use thereof.

  Since polyethylene terephthalate is excellent in mechanical strength, heat resistance, transparency and gas barrier properties, it is particularly used as a material for hollow containers for filling beverages such as mineral water, tea, carbonated drinks and juices.

  Mineral water, tea, juice, etc. are filled in the hollow container at high temperature (80 ° C. to 95 ° C.) for sterilization treatment, and therefore, a heat resistant hollow container having excellent transparency and heat resistance is used.

  As a method for improving the heat resistance of the molded product, the ethylene terephthalate unit is the main component, the proportion of diethylene glycol units is 1.0 to 2.5 mol% in the total diol units, and the content of the cyclic trimer is 0.5. A method has been proposed in which 0.1 to 45 ppb of polyethylene is blended with a polyester resin of not more than% by weight to increase the crystallization speed (JP-A-9-151308: Patent Document 1).

  On the other hand, as a method for lowering the plasticizing temperature, it has been proposed to use polyethylene terephthalate obtained by copolymerizing a small amount of isophthalic acid and diethylene glycol (Japanese Patent Laid-Open No. 2006-104304: Patent Document 2).

  However, any method is not sufficient to achieve both a low plasticization temperature and heat resistance. Polyethylene terephthalate resin with a low level of diethylene glycol units has high crystallinity and can increase the heat resistance of the molded product, while the molding temperature when molding bottles using pellets is high, and the resin during molding There was a problem that decomposition was accelerated and the amount of acetaldehyde increasing the flavor of bottles and the like increased.

JP-A-9-151308 JP 2006-104304 A

  An object of the present invention is to provide a polyethylene terephthalate resin pellet capable of lowering the plasticizing temperature while maintaining the heat resistance and transparency of the obtained molded article, a method for producing the same, and an application thereof.

  The present inventors diligently studied to achieve the above-described problems. As a result, polyethylene terephthalate having a low level of diethylene glycol unit was considered to have high crystallinity due to the high regularity of its molecular structure, and the crystallite size could not be reduced. It was found that a relatively small crystallite size can be generated by precisely controlling the production conditions. Furthermore, by providing the polyethylene terephthalate resin and / or pellets thereof, the present inventors have found that the molded article has excellent heat resistance and transparency, and that the molding temperature during molding such as injection molding can be lowered, thereby reaching the present invention. did.

That is, the present invention
(i) mainly composed of ethylene terephthalate units, and the proportion of diethylene glycol units is 0.7 to 1.0% by weight based on the total polymer units;
(ii) the intrinsic viscosity is 0.70 to 1.0 dl / g,
(iii) The crystallite size measured and calculated by X-ray diffraction method is 54 to 64 mm,
(iv) the acetaldehyde content is 2.0 ppm or less,
(v) The invention relates to a polyethylene terephthalate resin pellet, characterized in that the haze of a 5 mm thick portion of a square plate injection-molded using the pellet is 14% or less.

  The molded body obtained from the polyethylene terephthalate resin pellets of the present invention is excellent in heat resistance and transparency, and can lower the plasticizing temperature during melt molding such as injection molding. Byproduct of cyclic trimer can be suppressed. Further, according to the present invention, a polyethylene terephthalate resin pellet capable of producing a molded article excellent in heat resistance and transparency, and capable of lowering the plasticizing temperature when melt molding such as injection molding, and the like A manufacturing method thereof can be provided. The molded body according to the present invention is excellent in heat resistance and transparency, and is suitable for various molded products and containers.

FIG. 1 is a perspective view showing a stepped square plate-like molded body used for haze measurement.

<Polyethylene terephthalate resin pellet (A)>
The polyethylene terephthalate resin pellet (A) of the present invention is mainly composed of ethylene terephthalate units, and the proportion of diethylene glycol units is 0.7 to 1.0% by weight, preferably 0.8 to 1.0%, based on all polymer units. Including in the range of% by weight, the intrinsic viscosity (IV) is in the range of 0.70 to 1.0 dl / g, preferably in the range of 0.72 to 0.90 dl / g.

  In the polyethylene terephthalate resin pellet (A) of the present invention, the proportion of units consisting of terephthalic acid and ethylene glycol with respect to all structural units is 95% by weight or more, more preferably 97% by weight or more, but the effect of the present invention is not impaired. In the range, an acid component other than terephthalic acid, a diol other than ethylene glycol and diethylene glycol, and / or a glycol component may be included.

  If the content of the diethylene glycol unit is in the above range, the crystallinity is moderately high, so that the crystallization rate of the polyethylene terephthalate resin pellets does not decrease in the solid phase polymerization process, and during the solid phase polymerization process or molding process. In particular, it is preferable because the pellets are hardly fused. Moreover, since the heat resistance of the molded object obtained is excellent, it is preferable.

Polyethylene terephthalate resin pellets (A) having an intrinsic viscosity (IV) in the above range are preferred because the moldability during injection molding and hollow molding is good.
The polyethylene terephthalate resin pellet (A) of the present invention has a crystallite size in the range of 54 to 64 mm, preferably 55 to 63 mm.

Further, the microcrystal size of the polyethylene terephthalate resin pellet (A) of the present invention is measured by attaching one pellet to a holder using an X-ray diffractometer (high resolution small angle X-ray scatterer manufactured by Rigaku Corporation). It was. It was obtained by multiplying the obtained value (long period) by the crystallinity of the pellet (ratio of crystal part) obtained by the following formula.
Crystallinity = 1455 × (pellet density−1335) / (pellet density × (1455-1335))
1335 (kg / m ³ ): Amorphous density of polyethylene terephthalate resin pellets 1455 (kg / m ³ ): Crystal density of polyethylene terephthalate resin pellets

  When the crystallite size is larger than 64 mm, the minimum plasticization temperature is increased, and as a result of promoting the decomposition of the resin during molding, acetaldehyde is increased and the flavor is deteriorated. On the other hand, if the crystallite size is too small, it is not preferable because the pellets may be fused in the solid phase polymerization process or the molding process.

  Furthermore, the polyethylene terephthalate resin pellet (A) of the present invention has a haze of 14% or less, preferably 13% or less of a 5 mm thick portion of a square plate injection-molded using the resin pellet (A). If the haze of the 5 mm thick portion of the square plate exceeds 14%, the transparency of the corresponding molded bottle deteriorates and the quality of the beverage bottle deteriorates.

Here, the haze of the 5 mm thick portion of the injection-molded square plate is a stepped square plate having the shape shown in FIG. 1 in this embodiment (the thickness of the A portion is about 6 mm and the thickness of the B portion is about 4 mm, the thickness of C part is about 2 mm, the thickness of D part is about 7 mm, the thickness of E part is about 5 mm, and the thickness of F part is 3 mm). After the start, for the 11th to 15th molded bodies, using a haze meter (HZ-V3) manufactured by Suga Test Instruments Co., Ltd., the haze of the 5 mm thickness part (E part) of the molded product was measured, and 5 sheets It calculated | required from the average value of. The density of the polyethylene terephthalate pellets of the present invention is 1400 kg / m ³ to 1420 kg / m ³ . When the density is larger than 1420 Kg / m ³ , the melting point becomes high and the plasticization lower limit temperature becomes high. On the other hand, if it is less than 1400 kg / m ³ , the pellets are fused in the solid phase polymerization step or the molding step, which is not preferable.

  Moreover, the acetaldehyde content of the polyethylene terephthalate resin pellet (A) of the present invention is 2.0 ppm or less, and the acetaldehyde content in the molded product when the pellet (A) is molded is preferably 18 ppm or less.

<Polycondensation catalyst (B)>
The polycondensation catalyst (B) according to the present invention is a polycondensation catalyst (B) that is soluble and / or insoluble in the reaction mixture during melt polycondensation, and a germanium compound, a titanium compound, and an aluminum compound are used alone or in combination. . As the germanium compound, germanium dioxide, germanium tetraethoxide, or the like is used. Titanium alkoxides such as titanium tetrabutoxide and titanium tetraisopropoxide as titanium compounds, reaction products of titanium alkoxide compounds and organic phosphorus compounds described in JP-A-2005-325201, titanium oxalate, titanium citrate, etc. And titanium oxide compounds partially containing a Ti—OH bond described in WO 03/72633. The catalyst is used in an amount of 0.1 to 400 ppm, preferably 0.5 to 300 ppm in terms of metal atoms, based on the total polymer weight to be produced.

<Dispersed particles (C)>
The dispersed particles (C) according to the present invention have an average particle diameter of 0.3 μm or less, preferably 0.2 μm or less, more preferably 0.001 to 0.3 μm, and most preferably 0.001 to 0.2 μm. Dispersed particles having a particle size and dispersed in polyethylene terephthalate resin.

  The dispersed particles (C1) according to the present invention are dispersed in the reaction liquid at the time of melt polycondensation, so that they are finely dispersed in the generated polyethylene terephthalate and become a crystal nucleating agent for polyethylene terephthalate. It is estimated that the crystallite size of the polyethylene terephthalate produced can be reduced.

  Examples of such dispersed particles (C) include elements of groups 1 to 3 and 13 to 16 of the periodic table, oxides, hydroxides, carbonates, silicates, sulfates, and mixtures of the elements. An inorganic compound (C1) is mentioned.

Among these dispersed particles (C1), oxides are preferable, and MgO, ZnO, and SiO ₂ are more preferable.
Other examples of the dispersed particles (C) according to the present invention include solid titanium compounds (C2) corresponding to the polycondensation catalyst (B), preferably titanium oxide compounds partially containing a Ti—OH bond. Can be used. Even when the solid titanium compound (C2) has a large particle size when the solid catalyst is prepared, the solid titanium compound (C2) is gradually dissolved in the produced polyethylene terephthalate and dispersed in the form of fine particles. Presumed to be an agent.

  Further, germanium dioxide which is preferably used as the polycondensation catalyst (B) is not present as dispersed particles in the polyethylene terephthalate because it dissolves in the reaction liquid at the time of melt polycondensation. Therefore, it is not used as the dispersed particles (C).

The average particle size of the dispersed particles (C) according to the present invention is a weight average value measured using a SALD2000J laser diffraction particle size distribution meter manufactured by Shimadzu Corporation.
Further, when the polycondensation catalyst (B) according to the present invention is dispersed as particles of 0.3 μm or less in the reaction liquid at the time of melt polycondensation, it can also be used as a part of the dispersed particles (C). . When dispersed particles having an average particle size exceeding 0.3 μm are used, the transparency of the resulting molded article is lowered. When the average particle size of the dispersed particles (C) is out of 0.001 μm, the nucleating agent effect is weak.

<Method for producing polyethylene terephthalate resin pellet (A)>
The polyethylene terephthalate resin pellet (A) of the present invention can be obtained by various known production methods for producing polyethylene terephthalate, and is characterized by a low level of diethylene glycol content and a small crystallite size. The production method can be given as an example.

<Production Example 1>
In the following step (a) and / or (b), 0.1 to 30 ppm of dispersed particles (C1) having an average particle size of 0.3 μm or less is added to the polyethylene terephthalate to be produced,
(a) oligomerization step,
(b) a melt polycondensation step,
(c) a precrystallization step of performing precrystallization in a temperature range of 110 to 180 ° C. for 10 minutes to 4 hours;
(d) A method of performing a solid phase polymerization step of reacting at 205 ° C to 230 ° C for 5 to 50 hours. Or

<Production Example 2>
In the following steps (a) and / or (b), 0.1 to 30 ppm in terms of titanium atoms is added to the dispersed particles (C2) made of a solid titanium compound, and the resulting polyethylene terephthalate is added,
(A) oligomerization step,
(B) melt polycondensation step,
(C) Preliminary crystallization step in which precrystallization is performed for 10 minutes to 4 hours in a temperature range of 110 to 180 ° C, and (d) Solid phase polymerization step in which the reaction is performed at 205 ° C to 230 ° C for 5 to 50 hours. There are methods.

Furthermore, as a specific example, the following method can be implemented as a feature.
(1) Solid titanium compound (C2) dispersed at an average particle size of 0.3 μm or less during melt polycondensation, for example, titanium oxide compounds partially containing Ti—OH bonds, with respect to the produced polyethylene terephthalate, Polyethylene terephthalate is melt polycondensed using 0.1 to 30 ppm in terms of titanium atoms. Next, a precrystallization step after melt polycondensation and before solid phase polymerization is carried out at a temperature range of 110 to 180 ° C. for 1 minute to 4 hours, and solid phase polymerization is carried out at 205 to 230 ° C. for 5 to 50 hours. In this case, in order to obtain an appropriate polycondensation rate, a polycondensation catalyst different from the solid titanium compound, preferably in combination with a germanium compound, 0.1 0.1 in terms of metal atom with respect to polyethylene terephthalate to be produced. It is used so that it may become -400ppm, Preferably it is 0.5-300ppm. In this case, the solid titanium compound can also be added in the oligomerization step as long as the effects of the present invention are not impaired.

  (2) The dispersed particles (C1) having an average particle size of 0.3 μm or less are dispersed in an amount of 0.1 to 30 ppm in terms of metal atoms with respect to the polyethylene terephthalate to be produced, and then polyethylene terephthalate is melt polycondensed and then melted A method in which the precrystallization step after the polycondensation and before the solid phase polymerization is performed at a temperature range of 110 to 180 ° C. for 1 minute to 4 hours, and further solid phase polymerization is performed at 205 to 230 ° C. for 5 to 50 hours. Even in this case, the dispersed particles (C1) can be added in the oligomerization step.

  When the polyethylene terephthalate resin pellet (A) is produced by the method described in (1) above, the dispersed particles (C1) and the dispersed particles (C2) may be used in combination. The total amount of the dispersed particles (C1) and the dispersed particles (C2) needs to be in a range of 0.1 to 30 ppm with respect to polyethylene terephthalate to be generated in terms of metal atoms.

  Moreover, in order to adjust the content of diethylene glycol within the above range, since diethylene glycol is partially produced as a by-product from ethylene glycol used as the main raw material, an additive that suppresses the formation of diethylene glycol is used.

  As such an additive, a tertiary amine such as triethylamine, a quaternary ammonium hydroxide such as tetrabutylammonium hydroxide, and an inorganic base such as lithium carbonate are used in an amount of 0.001 to 10% by weight, preferably 0.005 to 1% by weight can be used. The preparation of a diol component mainly composed of ethylene glycol and an acid component mainly composed of terephthalic acid used as a polymerization raw material is diol component / acid component (molar ratio) = 1.00 to 1.40, preferably 1. By using 0.000 to 1.30, the content of diethylene glycol can be adjusted as appropriate to obtain a diethylene glycol content within the above range.

The polyethylene terephthalate resin pellet (A) of the present invention can be produced by referring to various known production methods in addition to the above conditions. That is,
A raw material containing terephthalic acid and ethylene glycol forms an oligomer in the presence of an esterification catalyst, and is subjected to melt polycondensation under high temperature and reduced pressure in the presence of a polycondensation catalyst and a stabilizer to form a polymer. As the esterification catalyst, terephthalic acid is an autocatalyst for esterification, and thus it is not necessary to use it. The number average molecular weight of the oligomer obtained by this step is usually 500 to 5,000.

  As the polycondensation catalyst, a germanium compound, a titanium compound, or an aluminum compound is used alone or in combination. Moreover, phosphorus compounds, such as phosphate ester, phosphoric acid, hypophosphorous acid, polyphosphoric acid, are used as a stabilizer used at the time of polycondensation.

The catalyst is used in an amount of 0.1 to 400 ppm, preferably 0.5 to 300 ppm as the weight of the metal in the catalyst in the total produced polymer. The proportion of the stabilizer used is 0.1 to 1000 ppm, preferably 0.5 to 200 ppm, based on the total polymerization raw material, as the proportion of phosphorus atoms in the stabilizer. Here, the reaction temperature and pressure of the esterification reaction are 240 to 280 ° C. and 1 to 3 kg / cm ² G. The reaction temperature and pressure during polycondensation are 250 to 300 ° C. and 500 to 0.1 mmHg, and the polyethylene terephthalate resin thus obtained is 0.40 to 0.75 dl / g. Next, the polymer obtained by the above melt polycondensation is subjected to solid phase polymerization, but before the solid phase polymerization, the polymer obtained by melt polycondensation is dried at 110 to 180 ° C., preferably 140 to Perform at 180 ° C. for 1 minute to 4 hours. If the precrystallization temperature is higher than this range, a polymer having a crystallite size larger than the desired crystallite size is generated, the plasticization lower limit temperature is increased, and as a result of promoting resin decomposition, the flavor of the molded product is deteriorated. . The solid phase polymerization step comprises at least one stage and is usually 205 to 230 ° C., preferably 210 to 230 ° C., 1 kg / cm ² G to 10 mmHg, preferably 0.5 kg / cm ² G to 10 mmHg, 50 hours or less. , Preferably 10 to 25 hours. The intrinsic viscosity of the polyethylene terephthalate resin pellet (A) obtained by solid phase polymerization is 0.70 to 1.0 dl / g.

<Method for forming hollow container>
Since the polyethylene terephthalate resin pellet (A) of the present invention can lower the molding temperature in melt molding such as injection molding and extrusion molding, the resulting molded product, for example, preforms and by-products such as acetaldehyde in the material of the hollow container are used. Can be reduced.

As a method for forming a hollow container, the hollow container is generally formed by two steps of injection molding and blow molding.
First, the moisture content of the polyethylene terephthalate resin pellet (A) of the present invention is adjusted to 50 ppm or less by dehumidifying air drying. Next, the preform is supplied to a molding machine such as an injection molding machine to form a preform called a preform. In this step, the pellet is put into a cylinder on which a screw is mounted, and the resin is plasticized (melted) by rotating the screw, then injected into a mold, cooled, solidified, and taken out to obtain a preform. The set temperature of the cylinder is generally 280 to 300 ° C.

  This preform is then fed to a blow molding machine. The blow molding machine comprises two steps, a heating step and a blowing step. In the heating step, the preform is heated to a predetermined temperature using, for example, an infrared heater to soften the material. Next, the heated preform is transferred to a blow process, inserted into a mold having a predetermined shape, stretch blow-molded with a rod called a stretch rod and high-pressure air, and taken out from the mold to form a hollow container. Normally, blow molding is a molding system that performs heating and blow continuously.

  There are two major blow molding methods. When molding a non-heat-resistant hollow container, the heated preform is blow-molded in a mold and immediately taken out from the mold. On the other hand, the heat-resistant hollow container relaxes the distortion generated at the time of blowing (stretching) and imparts heat resistance by a technique called heat setting by adjusting the mold temperature to a high temperature of 130 ° C. or higher. The preform temperature at the time of blowing is the surface temperature, and is generally 100 to 115 ° C.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
The physical properties of the polyethylene terephthalate resin pellets obtained in Examples and Comparative Examples were measured by the following methods.

(1) Determination of diethylene glycol copolymerization amount A sample is precisely weighed in a flask and hydrolyzed with monoethanolamine. Excess monoethanolamine is neutralized with terephthalic acid and quantified by GC (gas chromatography) using 1,6-hexanediol as an internal standard. A value obtained by dividing the amount of diethylene glycol quantified by this analysis method by the amount of sample used is defined as a copolymerization amount (wt%) of diethylene glycol.

(2) Measurement of Intrinsic Viscosity (IV) Intrinsic viscosity was determined by heating and dissolving 0.5 g of polyethylene terephthalate resin in 100 ml of a tetrachloroethane / phenol = 50/50 (wt% / wt%) mixed solution, and then cooling to 25 It was calculated from the solution viscosity measured at ° C.

(3) Measurement of microcrystal size It measured by the method of the above-mentioned.

(4) Measurement of acetaldehyde A sample (2.0 g) is weighed and freeze-ground using a freezer mill. The ground sample is put into a vial bottle purged with nitrogen, and further an internal standard substance (acetone) and water are added and sealed. The vial was heated with a dryer at 120 ± 2 ° C. for 1 hour, and then the supernatant was injected into a gas chromatography and measured.

(5) Measurement of haze Polyethylene terephthalate resin pellets were dried at 150 ° C. for 15 hours using a vacuum dryer. The water content in the dried resin pellets was 40 ppm or less. The dried polyethylene terephthalate resin pellets were fed at a rotational speed corresponding to 5 × 10 ⁻³ m ³ / hour using a screw feeder, and the cylinder set temperature was 295 ° C. using Meiko Seisakusho M70B. Molding was performed with a molding cycle of 70 seconds, a screw speed of 120 rpm, and a metering of 18 seconds to obtain a stepped square plate-like molded product. The stepped square plate-like molded body has a shape as shown in FIG. 1, and the thickness of the A part is about 6 mm, the B part is about 4 mm, the C part is about 2 mm, and the D part is thick. The thickness is about 7 mm, the thickness of the E part is about 5 mm, the thickness of the F part is 3 mm, and the weight is 75 g.

  After the start of injection molding, the haze of the 5 mm thickness part (E part) of the molded product is measured for the 11th to 15th molded articles using a haze meter (HZ-V3) manufactured by Suga Test Instruments Co., Ltd. And the average value of 5 sheets was shown as 5 mm haze.

(6) Evaluation of heat resistance The polyethylene terephthalate resin pellets were dried by the same method as in the above haze measurement, and a preform was molded at a resin temperature of 295 ° C. using an SE-180 injection molding machine manufactured by Sumitomo Heavy Industries. The preform plug portion was heated and crystallized with a home-made plug portion crystallization apparatus, then biaxially stretch blow-molded using a Corpoplast BLOWMAX 6E stretch blow molding machine, and subsequently set at about 150 ° C. The mold was heat-set in a mold for 1.5 seconds to obtain a 500 ml hollow molded container. The capacity (A) after storing the hollow molded container in a 40 ° C., 95% RH atmosphere for 3 days and the cap (capped with hot water of 87 ° C. after storing in a 40 ° C., 95% RH atmosphere for 3 days) The volume shrinkage (| 1−B / A | × 100) was calculated from the ratio of the capacity (B) after being kept at 23 ° C. for 10 minutes at room temperature and then kept in a 23 ° C. water bath for 1 hour. The case where the volume shrinkage was 2% or less was marked as ◯, the case where it was 2.1 to 3%, and the case where it was 3.1% or more was marked as x.

(7) Plasticization minimum temperature The polyethylene terephthalate resin pellet obtained by the said method was dried for 4 hours using 170 degreeC dehumidification air, and the moisture content was adjusted to 50 ppm or less. The dried resin pellets were put into a SE180DU-C150 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., and molding was carried out at a cylinder set temperature of 295 ° C., a screw rotation speed of 150 rpm, and a cycle time of 25 seconds. Four preforms are obtained per shot, each weighing 28 g. The appearance of the preform was observed and the presence or absence of a whitened product due to unmelting was confirmed. If no whitening was observed, molding was performed with the cylinder set temperature reduced by 5 ° C., and the presence or absence of whitening of the preform was confirmed again. This operation was repeated until whitening of the preform was observed, and (the set temperature of the cylinder when whitening of the preform was observed) + 5 ° C. was set as the plasticization lower limit temperature.

(8) Measurement of molded product acetaldehyde The polyethylene terephthalate resin pellets obtained by the above method were dried by the same method as the measurement of haze. The dried polyethylene terephthalate was used as the plasticizing lower limit temperature determined above using a SE-180DU-C150 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., molding cycle 25 seconds, screw rotation speed 150 rpm, lightweight 5 seconds. To obtain a preform. Four preforms are obtained per shot, each weighing 28 g.

  About the 20th molded article after the start of molding, 2.0 g of a sample is weighed and freeze-ground using a freezer mill. The ground sample is put into a vial bottle purged with nitrogen, and further an internal standard substance (acetone) and water are added and sealed. The vial was heated with a dryer at 120 ± 2 ° C. for 1 hour, and then the supernatant was injected into a gas chromatography and measured.

[Example 1]
[Manufacture of polyethylene terephthalate resin and resin pellets]
Using the continuous polycondensation apparatus in which the first, second, third, fourth and fifth reactors are tank-type and the sixth reactor is a biaxial rotating horizontal reactor, By operating as described above, continuous polymerization was carried out to produce a polyethylene terephthalate resin.

  3750 parts by weight of a reaction solution was previously retained, and 1437 parts by weight of high-purity terephthalic acid per hour and ethylene glycol 520 were added to a first reactor maintained at 255 ° C. under stirring and a nitrogen atmosphere under a condition of 0.17 MPaG. A slurry prepared by mixing parts by weight and a slurry prepared by mixing 0.055 parts of hourly magnesium oxide (Wako Pure Chemical Industries, mean particle size 0.05 μm, purity 99.9%) and 55 parts of ethylene glycol. And 0.03 part by weight of a 20% aqueous solution of tetraethylammonium were continuously fed to carry out the first stage esterification reaction. In the first stage esterification reaction, a mixed solution of 203 parts by weight of water and 3 parts by weight of ethylene glycol was distilled off. In addition, the first stage esterification reaction product was controlled so that the average residence time was 2.0 hours, and the second reaction was continuously maintained at 260 ° C. and 0.08 MPaG under stirring. Led to the vessel.

In this reactor 2, a homogeneous solution of 0.49 parts by weight of germanium dioxide and 49 parts by weight of ethylene glycol per hour (amorphous GeO ₂ was dissolved by heating in ethylene glycol and used as a GeO ₂ concentration of 1% by weight). Was continuously supplied, and a mixed solution of 84 parts by weight of water and 7 parts by weight of ethylene glycol was continuously distilled off to continue the second stage esterification reaction. Further, the second stage esterification reaction product was controlled so that the average residence time was 2.0 hours, and the third reactor was maintained under normal pressure at 265 ° C. with continuous stirring. Led to.

  In this third reactor, a uniform solution in which 1.23 parts by weight of trimethyl phosphate and 22 parts by weight of ethylene glycol are mixed is continuously fed, and 21 parts by weight of water and 38 parts by weight of The mixed solution with ethylene glycol was continuously distilled off, and the third-stage esterification reaction was continued.

  This third stage esterification reaction product was also controlled to have an average residence time of 2.0 hours and led to a fourth reactor maintained at 9 kPa abs at 275 ° C. with continuous stirring. In this fourth reactor, a mixture of 62 parts by weight of ethylene glycol and 6 parts by weight of water was continuously distilled off to carry out the first stage polycondensation reaction. In addition, this first stage polycondensation reaction product was controlled in such a way that the average residence time was 1.0 hour, and was continuously supplied to a fifth reactor maintained at 280 ° C. and 0.7 kPa abs. Led.

In this fifth reactor, a mixed solution of 26 parts by weight of ethylene glycol and 3 parts by weight of water was continuously distilled off, and the second stage polycondensation reaction was continued. In addition, the second stage polycondensation reaction product is controlled so that the average residence time is 1.0 hour, continuously under the conditions of 280 ° C. to 285 ° C. and 0.1 to 0.3 kPa abs. It was led to the sixth reactor which is a maintained horizontal biaxial rotary reactor. In the sixth reactor, the reaction solution of 12 parts by weight of ethylene glycol and 1 part by weight of water was continuously distilled off, and the third-stage polycondensation reaction was continued. The third stage polycondensation reaction product is controlled so that the average residence time is 2.5 hours, and is continuously drawn out in a strand form from the reactor by a polyester drawing device, and into the water. After being immersed and cooled, it was cut into chips by a strand cutter.
The IV of the polyethylene terephthalate resin obtained by the above liquid phase polymerization was 0.59 dl / g.

  Further, the polyethylene terephthalate resin obtained by the liquid phase polymerization is dried for about 2 hours at about 150 ° C. in a nitrogen atmosphere and crystallized, and then loaded into a tower-type solid phase polymerization vessel, and 10% at 225 ° C. in a nitrogen atmosphere. Time solid phase polymerization was performed. The polyethylene terephthalate resin pellets thus obtained had an IV of 0.80 dl / g, diethylene glycol (DEG) of 0.9% by weight, a crystallite size of 62 mm, a molded product of 5 mm haze of 5%, and bottle heat resistance. It was (circle) and the plasticization minimum temperature was 285 degreeC.

[Example 2]
In the first reactor of Example 1, a slurry prepared by mixing 1437 parts by weight of high-purity terephthalic acid per hour and 547 parts by weight of ethylene glycol and hourly zinc oxide (Wako Pure Chemical Industries, zinc oxide, average particle size of 0.1%). 02 μm, purity 99.9%) Polyethylene terephthalate resin pellets were prepared in the same manner as in Example 1 except that the slurry was changed to 0.028 parts and 28 parts of ethylene glycol. The results are shown in Table 1.

Example 3
In Example 1, in the first reactor, a slurry prepared by mixing 1437 parts by weight of high-purity terephthalic acid per hour and 547 parts by weight of ethylene glycol and magnesium oxide per hour (Wako Pure Chemical Industries, magnesium oxide, average particle size 0) 0.2 μm, purity 99.9%) Polyethylene terephthalate resin pellets were obtained in the same manner as in Example 1 except that the slurry was changed to 0.028 part and 28 parts of ethylene glycol and the solid phase polymerization time was changed to 6.5 hours. Prepared. The results are shown in Table 1.

Example 4
In Example 1, polyethylene terephthalate resin pellets were prepared by the same method as in Example 1 except that the crystallization temperature was changed to 170 ° C. The results are shown in Table 1.

Example 5
(Preparation of solid titanium compound)
In a 1000 ml glass beaker, 500 ml of deionized water was weighed, cooled in an ice bath, and 5 g of titanium tetrachloride was added dropwise with stirring. When the generation of hydrogen chloride ceased, it was removed from the ice bath, and 25% aqueous ammonia was added dropwise with stirring to adjust the pH of the solution to 8. The produced titanium hydroxide precipitate was separated from the supernatant by centrifugation at 2500 rpm for 15 minutes. Thereafter, the resulting titanium hydroxide precipitate was washed five times with deionized water. Solid-liquid separation after washing was performed by centrifugation at 2500 rpm for 15 minutes. Water was removed from the washed titanium hydroxide by drying under reduced pressure at 70 ° C. and 1.3 kPa abs for 18 hours to obtain a solid titanium compound. The obtained solid titanium compound was pulverized into particles of about 10 μm before use with a polycondensation catalyst.

The amount of water adhering to the solid titanium compound thus obtained was measured with a Karl Fischer moisture meter and found to contain 6.7% by weight of water. In addition, when the weight loss by heating was measured by thermogravimetry, the weight decreased to 7.50% by weight of the initial weight by 280 ° C. and further 2.17% by weight from 280 ° C. to 600 ° C. It was found to be due to desorption. Since nitrogen contained in the catalyst is 1.3% by weight and chlorine is contained only at 14 ppm, it is considered that nitrogen is not derived from ammonium chloride but derived from ammonia. From these results, it was found that the obtained solid titanium compound had a molar ratio of titanium to hydroxyl group of 1: 0.15. Nitrogen was analyzed by a trace total nitrogen analyzer (chemiluminescence method), and chlorine was analyzed by chromatography and calculated as desorbed as ammonia and hydrogen chloride, respectively.
The content of titanium in the solution measured using an ICP measuring device was 30% by weight.

(Manufacture of polyethylene terephthalate resin and resin pellets)
Using the continuous polycondensation apparatus in which the first, second, third, fourth and fifth reactors are tank-type and the sixth reactor is a biaxial rotating horizontal reactor, By operating as described above, continuous polymerization was carried out to produce a polyethylene terephthalate resin.

  3750 parts by weight of the reaction liquid was retained in advance, and 1437 parts by weight of high-purity terephthalic acid per hour and ethylene glycol 579 were added to a first reactor maintained at 255 ° C. under stirring and a nitrogen atmosphere under a condition of 0.17 MPaG. A slurry prepared by mixing parts by weight was continuously supplied to perform the first stage esterification reaction. In the first stage esterification reaction, a mixed solution of 203 parts by weight of water and 3 parts by weight of ethylene glycol was distilled off. In addition, the first stage esterification reaction product was controlled so that the average residence time was 2.0 hours, and the second reaction was continuously maintained at 260 ° C. and 0.08 MPaG under stirring. Led to the vessel.

  In this reactor 2, a slurry of 0.165 parts by weight of the above-prepared solid titanium compound and 54 parts by weight of ethylene glycol is continuously supplied, and 84 parts by weight of water and 7 parts by weight of water are continuously supplied. Part of the mixed solution with ethylene glycol was continuously distilled off, and the second stage esterification reaction was continued. Further, the second stage esterification reaction product was controlled so that the average residence time was 2.0 hours, and the third reactor was maintained under normal pressure at 265 ° C. with continuous stirring. Led to.

  In this third reactor, a homogeneous solution in which 0.06 parts by weight of 85% phosphoric acid and 0.3 parts by weight of ethylene glycol are mixed is continuously supplied, and 21 parts by weight of water is used per hour. And 38 parts by weight of ethylene glycol were continuously distilled off, and the third esterification reaction was continued.

  This third-stage esterification reaction product was also controlled to have an average residence time of 2.0 hours, and led to a fourth reactor maintained at 9 kPa abs at 275 ° C. with continuous stirring. In this fourth reactor, a mixture of 62 parts by weight of ethylene glycol and 6 parts by weight of water was continuously distilled off to carry out the first stage polycondensation reaction. In addition, this first stage polycondensation reaction product was controlled in such a way that the average residence time was 1.0 hour, and was continuously supplied to a fifth reactor maintained at 280 ° C. and 0.7 kPa abs. Led.

In this fifth reactor, a mixed solution of 26 parts by weight of ethylene glycol and 3 parts by weight of water was continuously distilled off, and the second stage polycondensation reaction was continued. In addition, the second stage polycondensation reaction product is controlled so that the average residence time is 1.0 hour, continuously under the conditions of 280 ° C. to 285 ° C. and 0.1 to 0.3 kPa abs. It was led to the sixth reactor which is a maintained horizontal biaxial rotary reactor. In the sixth reactor, the reaction solution of 12 parts by weight of ethylene glycol and 1 part by weight of water was continuously distilled off, and the third-stage polycondensation reaction was continued. The third stage polycondensation reaction product is controlled so that the average residence time is 2.5 hours, and is continuously drawn out in a strand form from the reactor by a polyester drawing device, and into the water. After being immersed and cooled, it was cut into chips by a strand cutter.
The IV of the polyethylene terephthalate resin obtained by the above liquid phase polymerization was 0.59 dl / g.

  Further, the polyethylene terephthalate resin obtained by the liquid phase polymerization is dried for about 2 hours at about 150 ° C. in a nitrogen atmosphere and crystallized, and then charged into a tower-type solid-phase polymerization vessel, and 13% at 225 ° C. in a nitrogen atmosphere. Solid phase polymerization was performed for time to obtain polyethylene terephthalate resin pellets. The results are shown in Table 1.

Example 6
In the first reactor of Example 5, polyethylene terephthalate resin pellets were prepared in the same manner as in Example 5, except that 1437 parts by weight of high-purity terephthalic acid per hour and 593 parts by weight of ethylene glycol were mixed. did. The results are shown in Table 1.

Example 7
Polyethylene terephthalate resin pellets were prepared in the same manner as in Example 5 except that the solid phase polymerization time in Example 5 was changed to 16 hours. The results are shown in Table 1.

Example 8
In the first reactor of Example 5, a slurry prepared by mixing 1437 parts by weight of high-purity terephthalic acid per hour and 524 parts by weight of ethylene glycol and magnesium oxide per hour (Wako Pure Chemical Industries, Magnesium oxide, average particle size 0. (05 μm, purity 99.9%) Polyethylene terephthalate resin pellets were prepared in the same manner as in Example 5 except that the slurry was changed to 0.055 part and 55 parts of ethylene glycol. The results are shown in Table 1.

[Comparative Example 1]
In the first reactor of Example 1, a slurry prepared by mixing 1437 parts by weight of high-purity terephthalic acid per hour and 575 parts by weight of ethylene glycol was continuously supplied, no magnesium oxide slurry was added, and the others were carried out. Polyethylene terephthalate resin pellets were prepared in the same manner as in Example 1. The results are shown in Table 2. Since the obtained polyethylene terephthalate resin pellets did not contain fine particles, the crystallite size was large and the minimum plasticization temperature was high.

[Comparative Example 2]
In the same manner as in Example 1, except that the particle size of magnesium oxide (Tateho Chemical Industry, magnesium oxide, average particle size of 0.5 μm, purity of 99.9%) was changed by the method of Example 1, polyethylene was used. Terephthalate resin pellets were prepared. The results are shown in Table 2. The haze value increased due to the large particle size.

[Comparative Example 3]
In the method of Example 1, in the first reactor, a slurry prepared by mixing 1437 parts by weight of high-purity terephthalic acid per hour and 300 parts by weight of ethylene glycol and magnesium oxide per hour (Tateho Chemical Industry, magnesium oxide, average particle size) A polyethylene terephthalate resin pellet was prepared in the same manner as in Example 1 except that the slurry was changed to a slurry prepared by mixing 0.275 parts by weight and 275 parts by weight of ethylene glycol (diameter 0.5 μm, purity 99.9%). Prepared. The results are shown in Table 2. Since the obtained polyethylene terephthalate resin pellet had a large amount of fine particles added, the haze value increased.

[Comparative Example 4]
Polyethylene terephthalate resin pellets were prepared in the same manner as in Example 1 except that the crystallization temperature in the solid phase polymerization was changed to 190 ° C. by the method of Example 1. The results are shown in Table 2. Since the obtained polyethylene terephthalate resin pellets had a high crystallization temperature, the crystallite size increased and the plasticization lower limit temperature increased.

[Comparative Example 5]
In the method of Example 1, polyethylene terephthalate resin pellets were prepared in the same manner as in Example 1 except that 12 parts by weight of diethylene glycol was added to the first reactor. The results are shown in Table 2. Since the obtained polyethylene terephthalate resin pellet had a high diethylene glycol concentration, the bottle heat resistance was lowered.

[Comparative Example 6]
In the method of Example 1, polyethylene terephthalate resin pellets were prepared in the same manner as in Example 1 except that the polymerization was performed so that the IV after liquid phase polymerization was 0.70 dl / g and the solid phase polymerization time was changed to 4 hours. Was prepared. The results are shown in Table 2. The obtained polyethylene terephthalate resin pellets were too small in crystallite size, and the pellets were fused together into a lump in the molding machine cylinder, so that they were plasticized by setting the molding temperature high.

[Comparative Example 7]
In the method of Example 1, polyethylene terephthalate resin pellets were prepared in the same manner as in Example 1 except that the solid phase polymerization temperature was changed to 200 ° C. and the solid phase polymerization time was changed to 20 hours. The results are shown in Table 2. The obtained polyethylene terephthalate resin pellets were too small in crystallite size, and the pellets were fused together into a lump in the molding machine cylinder, so that they were plasticized by setting the molding temperature high.

[Comparative Example 8]
(Preparation of catalyst)
In a 1000 ml glass beaker, 500 ml of deionized water was weighed and cooled in an ice bath, and then 5 g of titanium tetrachloride was added dropwise with stirring. When the generation of hydrogen chloride ceased, it was removed from the ice bath and 25% aqueous ammonia was added dropwise with stirring at room temperature to adjust the pH of the solution to 9. A 15% aqueous acetic acid solution was added dropwise thereto while stirring at room temperature to adjust the pH of the solution to 5. The formed precipitate was separated by filtration. The washed precipitate is retained in 30 wt% ethylene glycol-containing water as a slurry having a slurry concentration of 2.0 wt% for 30 minutes, and then granulated and dried at a temperature of 90 ° C. using a two-fluid nozzle type spray dryer. A solid titanium compound was obtained.

  The content of titanium in the solid titanium compound measured by ICP analysis was 34.8% by weight. Next, 170 g of ethylene glycol and 30 g of glycerin were weighed into a 300 ml glass flask, 5.75 g of the solid titanium compound was added thereto, and heated at 170 ° C. for 2 hours to dissolve. The titanium content in the solution measured by ICP analysis was 1.0% by weight.

[Manufacture of polyethylene terephthalate resin and resin pellets]
In the second reactor of Comparative Example 1, polyethylene terephthalate resin pellets were prepared in the same manner as in Comparative Example 1, except that 1.67 parts by weight of the titanium catalyst solution prepared above was added instead of the germanium oxide solution. The results are shown in Table 2. The obtained polyethylene terephthalate resin pellets had a large crystallite size and an increased plasticization lower limit temperature.

  The molded body obtained from the polyethylene terephthalate resin pellet (A) of the present invention is excellent in heat resistance and transparency, and can be lowered in plasticizing temperature during melt molding such as injection molding. As a by-product such as acetaldehyde can be suppressed, it can be molded by various known molding methods and used not only for hollow containers such as bottles but also for various applications such as sheets, films, fibers and pipes.

Claims (1)

A beverage container obtained by molding polyethylene terephthalate resin pellets satisfying the following (i) to (v).
(i) mainly composed of ethylene terephthalate units, and the proportion of diethylene glycol units is 0.7 to 1.0% by weight based on the total polymer units;
(ii) the intrinsic viscosity is 0.70 to 1.0 dl / g,
(iii) The crystallite size measured and calculated by X-ray diffraction method is 54 to 64 mm,
(iv) the acetaldehyde content is 2.0 ppm or less,
(v) The haze of the 5 mm thick portion of the square plate injection-molded using the pellets is 14% or less.

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