JP3727145B2 - Crystallization-inhibiting polyester - Google Patents

Description

【００８８】
【表２】

【００８９】
【表３】

【００９０】
【表４】

【００９１】
【表５】

【００９２】
［実施例４］
実施例１と同様にして透明な触媒溶液を調製した。
次に、テレフタル酸３６００部とエチレングリコール２１００部とを常温でスラリー化し、撹拌機付オートクレーブに仕込み、３ｋｇ／ｃｍ²の加圧下２７０℃にて反応させた。留出水量が６００部となった時点で放圧し、更に常圧にて２７０℃で反応させた。更に留出水量が７４０部以上となった時点で正燐酸を０．２１部とＤＥＧを表１に示した量になるように添加して、その１0分後に更に予め調製しておいた透明な触媒溶液を添加した。
【００９３】
引き続き２８５℃にて０．１ｍｍＨｇの減圧下で重縮合反応を約２．５時間実施して極限粘度数約０．６４のポリエチレンテレフタレートを得た。このポリマーを更に０．５ｍｍＨｇのＮ₂雰囲気下で、２１０℃で固相重合してポリマーの極限粘度数を約０．９９まで高めた。
【００９４】
この固相重合後のポリマーの品質を表１に示す。熱特性（ＤＳＣによる測定）と色相を表２に示す。このポリマーを用いて紡糸した繊維の品質と曳糸性を表５に示す。
【００９５】
［比較例７］
比較例１と同様にして触媒溶液を調製した。
この触媒溶液を三酸化アンチモンと酢酸マグネシウム・４水和物の混合溶液に代えて使用する以外は実施例４と同様にしてポリエチレンテレフタレートを得た。このポリマーの物性を表１に示す。
【００９６】
この固相重合後のポリマーの物性を表１に示す。熱特性（ＤＳＣによる測定）と色相を表２に示す。このポリマーを用いて紡糸した繊維の品質と曳糸性を表５に示す。
【００９７】
【発明の効果】
本発明によれば、触媒として安価なＳｂ系触媒を用いながらも結晶化の抑制されたＰＥＴを得ることができ、共重合成分を実質的に含有すること無く、曇り、白化の少ない結晶化の抑制されたＰＥＴを得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to polyethylene terephthalate with controlled crystallinity (hereinafter sometimes abbreviated as PET) capable of suppressing whitening and fogging of molded products and improving spinnability. It is a polyester that does not substantially contain a copolymer component such as an acid (hereinafter sometimes abbreviated as IA) and cyclohexanedimethanol (hereinafter sometimes abbreviated as CHDM), and an inexpensive Sb compound as a catalyst. The present invention relates to PET that can be produced using existing homo-PET production facilities.
[0002]
[Prior art]
Polyesters typified by polyethylene terephthalate are excellent in mechanical properties, heat resistance, weather resistance, electrical insulation resistance and chemical resistance, and are widely used as fibers, bottles, films and other molded articles.
[0003]
Such polyesters have different required properties depending on their uses.
In fiber and film applications, oriented crystallization is suppressed, polyester having high strength, excellent yarn-forming properties and film-forming properties is demanded.
[0004]
For packaging film and bottle applications, there is a strong demand for polyesters that are not cloudy and have excellent transparency.
[0005]
In general, improvement in strength of a molded product molded from a resin is a problem. One of the causes that make it difficult to improve the strength is that the resin crystallizes before sufficient molecular orientation occurs during stretch molding.
[0006]
One of the causes of fogging of films and bottles is that the polyester crystallizes during molding, and it is important to control the polymer so as to suppress crystallization.
[0007]
For example, as for polyester for bottles, it is common in Japan to use a GeO ₂ catalyst that does not easily become a crystal nucleus in polyester and has good transparency.
[0008]
However, in recent markets, there is a growing tendency to demand high-quality but cheaper materials, and the use of expensive GeO ₂ is a cause of lowering the international competitiveness of polymers, and it is a cheap metal. There is a demand for a method of using a compound as a polymerization catalyst.
[0009]
In addition to Ge-based catalysts, for example, Sb, Ti, Sn-based catalysts are known as metals having polyester polymerization activity.
[0010]
Sb ₂ O ₃ is often used as a polymerization catalyst, but it is reduced during polymerization to produce Sb metal, which gives the polyester a blackish color, makes the resin easier to crystallize, lowers strength, and generates haze. Bring.
[0011]
Ti and Sn-based catalysts generally have high polymerization activity, but on the other hand, the generation rate of side reaction products is high, and polymer coloring occurs. For this reason, it is difficult to use for the use for which transparency and a hue are especially calculated | required.
[0012]
JP-A-61-78828 and JP-A-4-57692 disclose polyester for bottles having no haze obtained by using a Sb compound as a polymerization catalyst and adding a predetermined amount of Mg or Mn compound and an alkali compound. Has been. However, as a result of studies by the inventors, this polyester has almost no effect of imparting low haze or suppressing crystallization.
[0013]
As one of the methods for imparting low haze to a polyester while using an Sb-based catalyst and suppressing crystallization, isophthalic acid (IA), cyclohexanedimethanol (CHDM), alkyldicarboxylic acid and excess diethylene glycol (hereinafter referred to as DEG) There is known a method of copolymerizing (which may be omitted). This method certainly has the effect of imparting low haze and suppressing crystallization. However, there is a problem in applications that require strength in that the presence of the copolymer component disturbs the molecular orientation and lowers the strength.
[0014]
In addition, when such a copolymerized PET is used, the odor and flavor may be greatly changed depending on the filler, which is problematic for bottles and food packaging films.
[0015]
[Problem to be Solved by the Invention]
An object of the present invention is to solve the above-mentioned problems, and to obtain PET in which crystallization is suppressed while using an inexpensive Sb-based catalyst as a catalyst. More specifically, an object of the present invention is to obtain PET that is substantially free of copolymerization components other than DEG and that is less cloudy, less whitened, and suppressed in crystallization. Another object of the present invention is to obtain PET with suppressed crystallization, which is less whitened when used as a preform for a bottle and less fogged when used as a bottle.
[0016]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors, as a packaging material, for example, a bottle material, have a low-fogging property and a low-whitening property, which are preferably suppressed in crystallization, and have a differential scanning calorimeter (hereinafter referred to as DSC). Exothermic peak detected when the polymer is heated from the amorphous state (hereinafter sometimes referred to as Tci) and exothermic peak detected when the polymer is cooled from the molten state (hereinafter tcd). It has been found that the value of (which may be referred to as) is a PET that satisfies a specific condition.
[0017]
According to the knowledge of the present inventors, the polyester of the present invention can be obtained by polymerizing PET using a predetermined amount of a polycondensation catalyst compound prepared from Sb ₂ O ₃ by a specific preparation method.
[0018]
The present invention is a polyester comprising terephthalic acid as an acid component of 95 mol% or more based on the total acid component, and ethylene glycol as a glycol component of 95 mol% or more based on the total glycol component, and Sb present in the polyester. The amount of the element is 60 ppm to 380 ppm with respect to the total amount of the polyester, the polyester satisfies the following formulas (1) and (2) for the thermal characteristics, and the polyester satisfies the following formula (3) for the intrinsic viscosity. The polyester satisfies the following formula (4) with respect to the diethylene glycol component as a constituent component thereof, Zn element is present in the polyester, and the abundance thereof is expressed by the following formula as a molar ratio with respect to the Sb element present in the polyester. A crystallization-inhibiting polyester characterized by satisfying the condition (5).
24.6 / [η] + 130.0 ≦ Tcd ≦ 24.6 / [η] +142.0 (1)
34.5 × [η] + 130.0 ≦ Tci ≦ 34.5 × [η] +142.0 (2)
[Tcd is the crystallization exothermic peak temperature (° C.) when the temperature is lowered by DSC, and Tci is the crystallization exothermic peak temperature (° C.) when the temperature is raised by DSC. ]
0.50 ≦ [η] ≦ 1.10 (3)
[[Η] represents the intrinsic viscosity, and [η] is a value calculated from the solution viscosity measured at 35 ° C. using a solvent of phenol / tetrachloroethane (= 3/2 component ratio). ]
DEG ≦ 2.50wt% (4)
[However, DEG represents the diethylene glycol component, and the numerical value is based on the total amount of the polymer. ]
0.05 ≦ Zn / Sb ≦ 5.0 (5)
The present invention is described in detail below.
[0019]
[polyester]
In the polyester used in the present invention, terephthalic acid is 95 mol% or more, preferably 97 mol% or more, more preferably 99 mol% or more, particularly preferably 99.5 mol% or more, based on the total acid component, PET having ethylene glycol as a glycol component of 95 mol% or more, preferably 96 mol% or more, based on the total glycol components.
[0020]
As the third component, components other than terephthalic acid, ethylene glycol and diethylene glycol can be contained in an amount of 3 mol% or less, preferably 1 mol% or less, more preferably 0.5 mol% or less. It needs to be in a range that does not impair the object of the present invention. It is particularly preferred that the third component is not copolymerized.
[0021]
As a third component other than diethylene glycol, aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, diphenyldicarboxylic acid and diphenylether dicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; fatty acid dicarboxylic acids such as adipic acid and sebacic acid; triethylene Aliphatic diols such as glycol, tetramethylene glycol and hexamethylene glycol; Alicyclic diols such as cyclohexanediol and cyclohexanedimethanol; Aromatic diols such as naphthalenediol, bisphenol A and resorcin; p-oxybenzoic acid, m-oxy Examples include oxycarboxylic acids such as benzoic acid, salicylic acid, mandelic acid, hydroacrylic acid, glycolic acid, 3-oxypropionic acid, asiatic acid, and quinobaic acid. .
[0022]
In addition, a polyfunctional group compound having a valence of 3 or more within the range in which the polyester is substantially linear, such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, gallic acid May be copolymerized, and if necessary, a monofunctional group compound such as o-benzoylbenzoic acid or naphthoic acid may be contained as a copolymerization component in a small proportion, for example, 1 mol% or less. Good.
[0023]
[Sb element content]
In the present invention, an Sb-based catalyst, preferably Sb ₂ O ₃ is used as the polyester polymerization catalyst.
[0024]
The amount of Sb element present in the polyester of the present invention is 60 ppm to 380 ppm, preferably 90 ppm to 300 ppm, based on the total amount of polyester. When the amount of the Sb element is less than 60 ppm, the polymerization activity is low, and the melt polymerization time is too long, so that there is no realistic productivity. When the amount of the Sb element exceeds 380 ppm, not only does the hue of the polymer deteriorate, but even if the Sb-based polymerization catalyst prepared by the method disclosed in this specification is used, Tci and Tcd cannot be controlled. I can't get it.
[0025]
[Tcd, Tci]
The polyester of the present invention satisfies the following formulas (1) and (2) for its thermal properties.
24.6 / [η] + 130.0 ≦ Tcd ≦ 24.6 / [η] +142.0 (1)
34.5 × [η] + 130.0 ≦ Tci ≦ 34.5 × [η] +142.0 (2)
[0026]
However, Tcd is the crystallization exothermic peak temperature (° C.) when the temperature is lowered in the DSC measurement, and Tci is the crystallization exothermic peak temperature (° C.) when the temperature is raised in the DSC measurement.
[0027]
PET having a Tcd higher than the range of the present invention is easily crystallized at the stage where the molten PET is cooled, and abrupt crystallization occurs at the time of molding, which makes it difficult to suppress orientation crystallization and suppress fogging. The suppression of fogging is particularly important in bottle and film applications.
[0028]
A PET having a Tcd lower than the range of the present invention is too amorphous, resulting in an excessively flexible PET and is not suitable for bottles, films, and industrial fiber applications.
[0029]
PET having a Tci higher than the range of the present invention is hardly crystallized at the stage of stretching. In order to impart an appropriate crystalline state to the molded product, it is necessary to perform stretching in a high temperature atmosphere in accordance with the crystallization temperature, but the stretching process is generally performed in the presence of air. Therefore, stretching at a high temperature causes deterioration of PET.
[0030]
When PET having a Tci lower than the range of the present invention is crystallized in the stretching process, it is difficult to suppress crystallization and control fogging, and PET with less fogging cannot be obtained.
[0031]
The PET of the present invention is a PET having crystallinity expressed by Tcd and Tci while using an Sb-based catalyst. Even with conventional PET, it is possible to achieve the same numerical values as in the present invention for Tci and Tcd by copolymerizing diethylene glycol (DEG) exceeding 2.5% by weight with respect to the total amount of the polymer. When PET is copolymerized in an amount exceeding 2.5% by weight based on the total amount of polymer, the strength, shrinkage, fragrance retention, and gas barrier properties are reduced.
[0032]
[Intrinsic viscosity number]
There is an optimum range for the intrinsic viscosity for each application, but polymers with an intrinsic viscosity of 0.5 or less cannot be accepted by the user as a product because the strength of the molded product is insufficient even for film and filament applications. When the intrinsic viscosity is 1.10 or more, the viscosity in the molding process increases, and not only the equipment is loaded, but also the shear heat generation becomes large and the deterioration of the polymer is noticeable, resulting in quality problems.
[0033]
The polyester of the present invention is preferably used as a filament for clothing. In this case, the intrinsic viscosity number is preferably 0.55 to 0.68. When the intrinsic viscosity is lower than this, the strength is insufficient, and when it is high, the comfort when used as clothing is deteriorated.
[0034]
The polyester of the present invention is preferably used as an industrial fiber for tire cords. In this case, the preferred intrinsic viscosity is 0.90 to 1.10. If the intrinsic viscosity is lower than this, the strength is insufficient, and if it is higher, it becomes difficult to spin stably.
[0035]
The polyester of the present invention is preferably used as a beverage bottle. In this case, a preferable intrinsic viscosity is 0.65 to 0.90. If the intrinsic viscosity is lower than this, the strength is insufficient, and if it is higher, the moldability is lowered.
[0036]
The polyester of the present invention is preferably used as a film. In this case, the preferred intrinsic viscosity is 0.55 to 0.68. If the intrinsic viscosity is lower than this, the strength is insufficient, and if it is higher, the moldability is lowered.
[0037]
[DEG]
In the present invention, the amount of the diethylene glycol (DEG) component in the polyester is 2.5% by weight or less based on the total amount of the polymer. When the amount of the DEG component exceeds 2.5% by weight, changes in physical properties such as strong elongation and shrinkage of the polyester molded article are severe, and the strong elongation, shrinkage, aroma retention, and gas barrier properties are lowered. Particularly in packaging applications, there are concerns about adverse effects such as the odor and flavor of the filler being changed and the gas barrier property being lowered.
[0038]
[Zn abundance]
In the present invention, zinc element is present in the polyester, and the amount of the element satisfies the condition of the following formula (5) as a molar ratio to Sb in the polyester.
0.05 ≦ Zn / Sb ≦ 5.0 (5)
[0039]
If the molar ratio is less than 0.05, a polymer having Tcd and Tci within the range of the present invention cannot be obtained. When this molar ratio exceeds 5.0, the heat resistance is lowered, and at the same time, foreign matter in the polymer is increased, and excessive addition results in the deterioration of physical properties as PET.
[0040]
This zinc element is derived from a catalyst, and the catalyst is preferably a Zn salt, more preferably an organic acid salt of Zn exemplified by zinc acetate and zinc benzoate, and particularly preferably zinc acetate.
[0041]
[Production method]
The polyester of the present invention can be obtained by directly esterifying terephthalic acid and ethylene glycol, adding a catalyst solution obtained by preparing an Sb-based polycondensation catalyst and a Zn salt, and subsequently melt polycondensation. it can.
[0042]
In the present invention, preparation of the catalyst solution is essential, and the catalyst solution is prepared as follows.
[0043]
The Sb-based polymerization catalyst is uniformly dissolved in ethylene glycol in advance, and the Zn salt is formed into a powder or uniform ethylene glycol solution at 60 ° C to 140 ° C, preferably 60 ° C to 120 ° C, particularly preferably 70 ° C to 100 ° C. , 20 minutes to 24 hours, preferably 30 minutes to 12 hours, particularly preferably 1 hour to 6 hours. If the temperature of the heating and stirring is less than 60 ° C., the Tcd of the obtained PET cannot be lowered to the range of the present invention, and the crystallization of PET cannot be suppressed. When the temperature of the heating and stirring is 140 ° C or higher, precipitated compounds are formed at the bottom of the reaction system, and suspended matter is generated on the solution surface. This reduces the stability of the catalyst solution and shortens the life of the filter installed in the preparation process. There is a risk of causing.
[0044]
The Sb-based polymerization catalyst and the Zn salt are prepared together as described above and simultaneously added to the reaction system. Unless prepared together and added at the same time, Tcd cannot be lowered to the range of the present invention and crystallization of PET cannot be suppressed.
[0045]
[Additives, etc.]
In the melt polycondensation, it is preferable to add a phosphorus compound as a stabilizer. The specific amount to be added varies depending on the reaction apparatus and should be appropriately adjusted.
[0046]
If necessary, other additives such as color adjusting agents, colorants, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, and the like may be added.
[0047]
After completion of the melt polycondensation, for example, it is melt-extruded, cooled in an appropriate refrigerant, for example, water, cut into an appropriate size, and formed into chips. The tip may be a rectangular parallelepiped, a cylinder, a dice or a sphere.
[0048]
The PET of the present invention may be subjected to solid phase polymerization after melt polycondensation to obtain a PET having a desired intrinsic viscosity.
[0049]
【Example】
Hereinafter, the present invention will be described in detail by way of examples.
In the examples, “parts” means parts by weight. Moreover, the measuring method of the characteristic used in the Example is shown below.
[0050]
1) Intrinsic viscosity number [η]:
It calculated from the solution viscosity measured at 35 degreeC using the mixed solvent of phenol / tetrachloroethane (weight ratio 60/40).
[0051]
2) Diethylene glycol (DEG) copolymerization ratio:
200 g of the polymer and 10 ml of hydrazine hydrate (hydrazine monohydrate) were mixed, and the polymer was completely decomposed at 150 ° C. for 10 minutes. The solution was analyzed by gas chromatography, and the proportion of diethylene glycol copolymerized in the polymer was determined from the detected concentration. A gas chromatography 263 type manufactured by Hitachi, Ltd. was used for gas chromatography.
[0052]
3) Thermal characteristics: DSC (differential scanning calorimeter) analysis Measurement was performed using a thermal analysis 2200 type differential scanning calorimeter manufactured by TA Instruments. A polymer chip sample of 10.0 mg was put in an aluminum pan, heated to 300 ° C. at a heating rate of 20 ° C./min, held for 2 minutes after reaching 300 ° C., and then quickly put into an ice bath. Quench in a test tube so that it does not come into direct contact with water. Thereafter, the temperature was raised again at 20 ° C./min, and the crystallization temperature Tci and the melting point Tm were determined. When the temperature reached 300 ° C., the temperature was maintained for 2 minutes, and then the temperature was lowered at 10 ° C./min. At that time, the crystallization peak when the temperature was lowered was defined as Tcd. Tci, Tm, and Tcd each read the maximum peak point.
[0053]
4) Hue:
The polymer was dried by heat treatment in a dryer at 140 ° C. for 60 minutes, and measured with a CM-7500 color machine manufactured by Color Machine.
[0054]
5) Metal content measurement:
The amount of metal in the polymer (unit: ppm) was measured by a predetermined method using fluorescent X-rays (fluorescent X-ray type 3270 manufactured by Rigaku Corporation).
[0055]
6) Film formation and quality evaluation:
The polymer was dried at 160 ° C., melt extruded at 280 ° C., and rapidly cooled and solidified on a casting drum maintained at 40 ° C. to obtain an unstretched film. This unstretched film was successively biaxially stretched under conditions of a longitudinal stretch ratio of 3.5 times and a transverse stretch ratio of 4.0 times, and a biaxially oriented film having a thickness of 25 μm was obtained under the condition of a heat treatment temperature of 215 ° C.
[0056]
7) Bottle formation and quality evaluation:
After drying the polymer at 160 ° C. for 5 hours, a 50 g preform was formed at a cylinder temperature of 285 ° C. using an injection molding machine Dynamelter M-100DM manufactured by Meiki Seisakusho, and this was blown and stretched in the axial direction. A bottle having a magnification of about 3 times, an internal volume of 1.5 liters, and a barrel thickness of 0.3 mm was obtained.
[0057]
The blow molding machine uses Cincinnati's Miraclone, and the heating conditions are 1 to 9 scales of the heater, dialing 1: 50%, 2-4: 45%, 5-8: 48%, 9: 70% The heating time was selected so as to minimize haze, and blow molding was performed.
[0058]
For the evaluation of transparency, the straight body portion was cut out, and the haze of the bottle body portion was measured with a haze meter to obtain the haze of the bottle. As the haze meter, a color and color difference metal model 1001DP manufactured by Nippon Denshoku Industries Co., Ltd. was used.
[0059]
The pressure strength indicates the pressure value when water is fed into the bottle using a hydraulic pump, the pressure is increased at 10 kg / min, and the bottle bursts.
[0060]
The buckling strength was obtained by sandwiching the bottle upright with an autograph (Shimadzu AG-100B type) pros head and applying a load to the bottle by narrowing the width of the pros head at a speed of 500 mm / min. At that time, the maximum load value measured until the bottle is greatly deformed is shown. The molding width is the difference between the maximum heating time and minimum heating time at which the haze of the molded bottle body is 1% or less when the bottle is blow molded with the above heating conditions (unit: seconds) It is. It can be said that it is a bottle polymer in which whitening is suppressed as the molding width time increases.
[0061]
8) Spinning and quality evaluation:
The polymer was dried at 160 ° C. for 5 hours, and then a 75 denier, 36 filament yarn was spun at a spinning temperature of 300 ° C., a cooling air line speed of 15 m / min (26 ° C., relative humidity of 70%) and a take-up speed of 3000 m / min. The number of yarn breaks per 1T of polymer at this time was observed. The number of yarn breaks reflects the effect of improving the spinnability by suppressing crystallization. Under this spinning condition, only the take-up speed was accelerated at a rate of 200 m / min, and the take-up speed when the yarn was completely broken was recorded as the total breaking take-up speed.
[0062]
9) Spinnability:
Spinning performance is achieved by using a spinneret having 30 spinning holes with a diameter of 0.3 mm, Sb around the outside of the spinning hole when melt spinning for 7 days at a discharge rate of 80 g / min, a discharge temperature of 285 ° C., and a winding speed of 1200 m / min. The height of the foreign material containing the metal and the occurrence of pending in the meantime were observed to evaluate the polymer yarn production.
The lower the height of the foreign matter on the die surface, the better the spinning property, and the lower the occurrence of pending, the better the spinning property.
[0063]
[Example 1]
0.01 mol of antimony trioxide and 0.01 mol of zinc acetate dihydrate were present in 329 g of ethylene glycol, and heated and stirred at 80 ° C. for 2 hours to prepare a transparent catalyst solution.
[0064]
3600 parts of terephthalic acid and 2100 parts of ethylene glycol were slurried at room temperature, charged into an autoclave equipped with a stirrer, and reacted at 270 ° C. under a pressure of 3 kg / cm ² . The pressure was released when the amount of distilled water reached 600 parts, and the reaction was further carried out at 270 ° C. at normal pressure. Further, when the amount of distilled water reached 740 parts or more, 0.21 part of orthophosphoric acid was added, and a catalyst solution prepared in advance so that the amount of antimony and zinc shown in Table 1 were further 10 minutes later. Was added.
[0065]
Subsequently, a polycondensation reaction was carried out at 285 ° C. under a reduced pressure of 0.1 mmHg for 2.5 hours to obtain polyethylene terephthalate having an intrinsic viscosity of about 0.645.
[0066]
The quality of this polymer is shown in Table 1. Table 2 shows the thermal properties (measured by DSC) and hue of this polymer. Table 3 shows the physical properties of this polymer as a film.
[0067]
[Comparative Example 1]
0.01 mol of antimony trioxide was added to 221 g of ethylene glycol and mixed by heating at 155 ° C. for 2 hours to prepare a catalyst solution.
[0068]
A polyethylene terephthalate was obtained in the same manner as in Example 1 except that this catalyst solution was used in place of the catalyst solution of Example 1.
[0069]
The quality of this polyethylene terephthalate is shown in Table 1. Table 2 shows the thermal properties (measured by DSC) and hue of this polymer. Table 3 shows the physical properties of this polymer as a film.
[0070]
[Example 2]
In the same manner as in Example 1, a transparent catalyst solution was prepared.
Next, 3600 parts of terephthalic acid and 2100 parts of ethylene glycol were slurried at room temperature, charged into an autoclave equipped with a stirrer, and reacted at 270 ° C. under a pressure of 3 kg / cm ² . The pressure was released when the amount of distilled water reached 600 parts, and the reaction was further carried out at 270 ° C. at normal pressure. Further, when the amount of distilled water reached 740 parts or more, 0.21 part of normal phosphoric acid and DEG were added so as to have the amounts shown in Table 1, and after 10 minutes, the transparent liquid prepared earlier. Catalyst solution was added.
[0071]
Subsequently, a polycondensation reaction was carried out at 285 ° C. under a reduced pressure of 0.1 mmHg for about 1.8 hours to obtain polyethylene terephthalate having an intrinsic viscosity of about 0.56. This polymer was further solid-phase polymerized at 210 ° C. in an N ₂ atmosphere of 0.5 mmHg to increase the intrinsic viscosity of the polymer to about 0.86.
[0072]
Table 1 shows the quality of the polymer after this solid phase polymerization. Table 2 shows thermal characteristics (measured by DSC) and hue. Table 4 shows the quality of bottles molded using this polymer.
[0073]
[Example 3]
0.01 mol of antimony trioxide and 0.005 mol of zinc acetate dihydrate were present in 275 g of ethylene glycol and heated and mixed at 80 ° C. for 2 hours to prepare a transparent catalyst solution.
[0074]
A polyethylene terephthalate having an intrinsic viscosity of about 0.86 was obtained in the same manner as in Example 2 except that this catalyst solution was used in place of the mixed catalyst solution of antimony trioxide and zinc acetate dihydrate.
[0075]
The properties of this polymer after solid phase polymerization are shown in Table 1. Table 2 shows the thermal characteristics (measured by DSC) and hue. Table 4 shows the quality of bottles molded using this polymer.
[0076]
[Comparative Example 2]
A catalyst solution was prepared in the same manner as in Comparative Example 1.
Polyethylene terephthalate was obtained in the same manner as in Example 2 except that this catalyst solution was used in place of the mixed catalyst solution of antimony trioxide and zinc acetate dihydrate. The properties of this polymer are shown in Table 1. Table 2 shows the thermal properties (measured by DSC) and hue of this polymer. Table 4 shows the quality of bottles molded using this polymer.
[0077]
[Comparative Example 3]
0.01 mol of antimony trioxide and 0.10 mol of zinc acetate dihydrate were present in 1297 g of ethylene glycol, and heated and mixed at 80 ° C. for 2 hours to prepare a transparent catalyst solution.
[0078]
A polyethylene terephthalate was obtained in the same manner as in Example 2 except that this catalyst solution was used in place of the catalyst solution of Example 2.
[0079]
The properties of this polymer are shown in Table 1, and the thermal properties (measured by DSC) and hue are shown in Table 2. Table 4 shows the quality of bottles molded using this polymer.
[0080]
[Comparative Example 4]
A transparent catalyst solution was prepared in the same manner as in Example 1.
Polyethylene terephthalate was obtained in the same manner as in Example 2 except that this catalyst solution was used instead of the catalyst solution in Example 2. Table 1 shows the physical properties of this polymer. The thermal properties (measured by DSC) and hue of this polymer are shown in Table 2. Table 4 shows the quality of bottles molded using this polymer.
[0081]
[Comparative Example 5]
A transparent catalyst solution was prepared in the same manner as in Example 1.
Immediately before the addition of this catalyst solution, polyethylene terephthalate was obtained in the same manner as in Example 2 except that 0.201 part of potassium acetate was added to the reaction system as a 5% ethylene glycol solution. Table 1 shows the physical properties of this polymer. The thermal properties (measured by DSC) and hue of this polymer are shown in Table 2. Table 4 shows the quality of bottles molded using this polymer.
[0082]
[Comparative Example 6]
0.01 mol of antimony trioxide was dissolved in 221 g of ethylene glycol, and heated and mixed at 155 ° C. for 2 hours to prepare a catalyst solution.
[0083]
0.01 mol of zinc acetate dihydrate was dissolved in 108 g of ethylene glycol and heated and mixed at 35 ° C. for 2 hours to prepare a catalyst solution.
[0084]
Next, 3600 parts of terephthalic acid and 2100 parts of ethylene glycol were slurried at room temperature, charged into an autoclave equipped with a stirrer, and reacted at 270 ° C. under a pressure of 3 kg / cm ² . The pressure was released when the amount of distilled water reached 600 parts, and the reaction was further carried out at 270 ° C. at normal pressure. Further, when the amount of distilled water reached 740 parts or more, 0.21 part of orthophosphoric acid and DEG were added so as to have the amounts shown in Table 1, and 10 minutes later, trioxide prepared in advance. A catalyst solution that was an ethylene glycol solution of antimony and a catalyst solution that was an ethylene glycol solution of zinc acetate dihydrate were added. This addition was performed so that the amounts of zinc and antimony to be added were as shown in Table 1.
[0085]
Subsequently, a polycondensation reaction was carried out at 285 ° C. under a reduced pressure of 0.1 mmHg for 1.8 hours to obtain polyethylene terephthalate having an intrinsic viscosity of about 0.56. This polymer was further solid-phase polymerized at 210 ° C. in an N ₂ atmosphere of 0.5 mmHg to increase the intrinsic viscosity of the polymer to about 0.86.
[0086]
Table 1 shows the quality of the polymer after this solid phase polymerization. The thermal properties (measured by DSC) and hue of this polymer are shown in Table 2. Table 4 shows the quality of bottles molded using this polymer.
[0087]
[Table 1]

[0088]
[Table 2]

[0089]
[Table 3]

[0090]
[Table 4]

[0091]
[Table 5]

[0092]
[Example 4]
A transparent catalyst solution was prepared in the same manner as in Example 1.
Next, 3600 parts of terephthalic acid and 2100 parts of ethylene glycol were slurried at room temperature, charged into an autoclave equipped with a stirrer, and reacted at 270 ° C. under a pressure of 3 kg / cm ² . The pressure was released when the amount of distilled water reached 600 parts, and the reaction was further carried out at 270 ° C. at normal pressure. Further, when the amount of distilled water reached 740 parts or more, 0.21 part of orthophosphoric acid and DEG were added so as to have the amounts shown in Table 1, and after 10 minutes, a transparent preliminarily prepared solution was prepared. The catalyst solution was added.
[0093]
Subsequently, a polycondensation reaction was carried out at 285 ° C. under a reduced pressure of 0.1 mmHg for about 2.5 hours to obtain polyethylene terephthalate having an intrinsic viscosity of about 0.64. This polymer was further solid-phase polymerized at 210 ° C. under an N ₂ atmosphere of 0.5 mmHg to increase the intrinsic viscosity of the polymer to about 0.99.
[0094]
Table 1 shows the quality of the polymer after this solid phase polymerization. Table 2 shows thermal characteristics (measured by DSC) and hue. Table 5 shows the quality and spinnability of fibers spun using this polymer.
[0095]
[Comparative Example 7]
A catalyst solution was prepared in the same manner as in Comparative Example 1.
Polyethylene terephthalate was obtained in the same manner as in Example 4 except that this catalyst solution was used in place of the mixed solution of antimony trioxide and magnesium acetate tetrahydrate. Table 1 shows the physical properties of this polymer.
[0096]
Table 1 shows the physical properties of the polymer after this solid phase polymerization. Table 2 shows thermal characteristics (measured by DSC) and hue. Table 5 shows the quality and spinnability of fibers spun using this polymer.
[0097]
【The invention's effect】
According to the present invention, it is possible to obtain PET in which crystallization is suppressed while using an inexpensive Sb-based catalyst as a catalyst, and it is possible to obtain crystallization with little clouding and whitening without substantially containing a copolymer component. Suppressed PET can be obtained.

Claims (8)

A polyester having terephthalic acid as an acid component of 95 mol% or more with respect to the total acid component and ethylene glycol as a glycol component of 95 mol% or more with respect to the total glycol component, and the amount of Sb element present in the polyester is The polyester satisfies the following formulas (1) and (2) with respect to the thermal characteristics thereof, and the polyester satisfies the following formula (3) with respect to the intrinsic viscosity. The diethylene glycol component as a constituent component satisfies the following formula (4), Zn element is present in the polyester, and the abundance is expressed by the following formula (5) as a molar ratio to the Sb element present in the polyester. A crystallization-inhibiting polyester characterized by satisfying the conditions.
24.6 / [η] + 130.0 ≦ Tcd ≦ 24.6 / [η] +142.0 (1)
34.5 × [η] + 130.0 ≦ Tci ≦ 34.5 × [η] +142.0 (2)
[Tcd is the crystallization exothermic peak temperature (° C.) when the temperature is lowered by DSC, and Tci is the crystallization exothermic peak temperature (° C.) when the temperature is raised by DSC. ]
0.50 ≦ [η] ≦ 1.10 (3)
[[Η] represents the intrinsic viscosity, and [η] is a value calculated from the solution viscosity measured at 35 ° C. using a solvent of phenol / tetrachloroethane (= 3/2 component ratio). ]
DEG ≦ 2.50wt% (4)
[However, DEG represents the diethylene glycol component, and the numerical value is based on the total amount of the polymer. ]
0.05 ≦ Zn / Sb ≦ 5.0 (5) The polyester according to claim 1, wherein the Sb element is derived from an Sb compound used as a polyester polymerization catalyst. The polyester according to claim 1, wherein the diol components constituting the polyester are ethylene glycol and diethylene glycol, and the ethylene glycol and diethylene glycol are 99.5 mol% or more based on the total diol components constituting the polyester. The filament for clothing made of polyester according to claim 1, wherein the intrinsic viscosity [η] of the polyester is 0.55 to 0.68. The industrial fiber for tire cords comprising the polyester according to claim 1, wherein the intrinsic viscosity [η] of the polyester is 0.90 to 1.10. The bottle made of polyester according to claim 1, wherein the intrinsic viscosity [η] of the polyester is 0.65 to 0.90. The film made of polyester according to claim 1, wherein the intrinsic viscosity [η] of the polyester is 0.55 to 0.68. The polyester according to claim 1, obtained by further solid-phase polymerization after melt polymerization.