TW419491B - Process for preparing polyethylene therephthalate - Google Patents

Abstract

Disclosed is a process for preparing polyethylene terephthalate a polyester preparation apparatus comprising an esterification reactor consisting of plural continuous esterification vessels, a liquid phase polycondensation reactor, and optionally, a solid phase polycondensation reactor, wherein said process comprises the steps of feeding a slurry containing terephthalic acid, ethylene glycol and an antimony compound to a first esterification vessel, and adding a phosphorus compound, and optionally, at least one compound selected from cobalt, magnesium and manganese compounds to a second or subsequent esterification vessel. By the use of this process, polyethylene terephthalate which has good hue and superior transparency and is suitably used for producing bottles can be prepared.

Description

r 419491 A7 B7 Yin Ben, Consumers Cooperative of Central Bureau of Standards, Ministry of Economic Affairs V. Description of invention j () Field of invention The present invention relates to a method for preparing polyethylene terephthalate, and more particularly to a method with good color and superior preparation. Method for transparent polyethylene terephthalate. BACKGROUND OF THE INVENTION Polyethylene terephthalate is widely used in the manufacture of, for example, fiber films, bottles and industrial materials. In particular, recently, a large number of polyethylene terephthalate bottles (PE bottles) have been used in place of glass bottles or metal cans, so the amount of polyethylene terephthalate used in bottles has increased. The polyethylene terephthalate used in the bottle needs to have good ductility, excellent transparency, good color and high pressure resistance. When preparing polyethylene terephthalate, many methods have been disclosed, and they have also been disclosed. There are many ways to add a catalyst to the production method of polyethylene terephthalate. For example, Japanese Patent Publication No. 9 1 9 9 3/1 9 76 discloses that antimony trioxide and osmic acid are simultaneously added to the esterification step = However, when antimony trioxide and phosphoric acid are simultaneously added to the esterification step, The precipitation of antimony metal makes the color and transparency of bottles made from the formed polyethylene terephthalate poor. Japanese Patent Publication No. 1 1 2 1 4/1 9 8 4 discloses a method of individually adding antimony compounds and phosphate triesters dissolved in ethylene glycol to different esterification devices. However, this method requires additional equipment to dissolve the antimony compound in ethylene glycol. Moreover, because ethylene glycol needs to be heated at high temperature to dissolve antimony (please read the “$” on the back before filling this page) This paper size is applicable to Chinese national standards (CMS > A4 specification (21〇297mm)- 4- Printed by the Central #Associate Bureau Employee Consumer Cooperative in the Ministry of Economy 41949 1 A7 ________B7 V. Description of the invention ί) compound, heating process can increase the amount of di (ethylene glycol), or make the formed polyethylene terephthalate The color of the ester becomes worse. As described above, the conventional method is not always suitable for preparing polyethylene terephthalate for bottles. OBJECTS OF THE INVENTION The present invention has met the aforementioned conditions, and the object of the present invention is to provide a method for preparing polyethylene terephthalate which has good color and superior transparency and is suitable for manufacturing bottles. SUMMARY OF THE INVENTION The present invention provides a method for producing polyethylene terephthalate in a polyester preparation device. The device includes an esterification reactor composed of a plurality of continuous esterification vessels, and a liquid phase polycondensation reactor. Wherein the method includes the following steps:-feeding a slurry containing terephthalic acid, ethylene glycol and an antimony compound into the first esterification vessel; and at least one of a phosphorus compound and a selectivity selected from a cobalt compound and a magnesium compound Compounds of manganese compounds and manganese compounds are added to a second or subsequent esterification vessel. In the present invention, antimony trioxide can be used as an antimony compound. The blending ratio of the antimony compound is in the range of 150 to 400 ppm based on terephthalic acid. It is desirable to prepare a slurry containing terephthalic acid, ethylene glycol and antimony compounds at a temperature of 0 to 50 ° C. (Please read the "Vi" notice on the back before filling in this page.) This paper size applies to the Chinese National Standard (CNS) A4 (210X297 mm) -5- Printed by the Bayong Consumer Cooperative of the Central Standardization Bureau of the Ministry of Economic Affairs 9 1 a? _______B7 _____Five 'invention description ") The reaction temperature in the first esterification vessel is expected to be in the range of 240 to 2700 ° C" Phosphorous compounds can be added in the form of aqueous solution or ethylene glycol solution, Cobalt compounds, magnesium compounds and manganese compounds. Except for terephthalic acid, isophthalic acid can be used as the dicarboxylic acid component at a dosage of 1 to 3 mole% based on the total amount of the dicarboxylic acid component. DETAILED DESCRIPTION OF THE INVENTION The method for preparing polyethylene terephthalate according to the present invention is described in detail below. In the present invention, a polyester polymerization device is used to prepare polyethylene terephthalate. The device includes an esterification reactor composed of several continuous esterification vessels, a liquid phase polycondensation reactor, and a selective solid phase. Polycondensation reactor. According to the present invention, a slurry containing terephthalic acid, ethylene glycol, and an antimony compound as a catalyst is fed into the first esterification vessel. Slurries containing terephthalic acid, ethylene glycol and antimony compounds can be prepared in batches or continuously using, for example, vertical or horizontal mixers equipped with spiral stirring blades. In the slurry, terephthalic acid and antimony compounds are dispersed or suspended in ethylene glycol. The temperature at which terephthalic acid, ethylene glycol and antimony compounds are mixed to prepare a slurry is usually in the range of 0 to 5 Ot, and 10 to 40 t: preferably. Within the aforementioned temperature range, antimony compounds are difficult to dissolve in ethylene glycol, while terephthalic acid and antimony compounds are dispersed or suspended in ethylene glycol to produce a slurry. Moreover, ethylene glycol is hardly damaged, and the amount of di (ethylene glycol) formation is reduced * The slurry contains 1 mol of terephthalic acid, usually 1 _ 0 2 to this paper standard is applicable to China National Standards (CNS) A4 Specifications (210X297mm) ~ (Please read the historical matters on the back before filling this page) 崠! 41 94 9 1 A7 B7 printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs _ V. Description of the invention) 2,0 mol of ethylene glycol, preferably 1.03 to 1.5 mol, and antimony metal It is shown that the antimony compound is usually 50 to 500 ppm based on 1 mole of terephthalic acid, and preferably 150 to 400 PPII. Examples of antimony compounds are antimony trioxide, antimony acetate and antimony trichloride. The average particle size of the antimony compound is usually about 5 to 20 sieve, preferably about 10 sieve. In the present invention, terephthalic acid and ethylene glycol are used as starting materials to prepare polyethylene terephthalate, but in addition, not more than 20 mol% of other dicarboxylic acids and / or Other diols. Examples of dicarboxylic acids other than terephthalic acid that can be used for copolycondensation include aromatic dicarboxylic acids such as phthalic acid (phthalic acid), isophthalic acid, naphthalenedicarboxylic acid 'diphenyl dicarboxylic acid Acids and diphenoxyethane dicarboxylic acids; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and decanedicarboxylic acids; and cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid acid. Examples of diols other than ethylene glycol that can be used for copolycondensation include aliphatic diols such as trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol and ten Dimethylene glycols; cycloaliphatic diols, such as cyclohexanedimethanol: and aromatic dihydroxy compounds, such as bisphenol, hydroquinone, and 2,2-bis (4-amyl_hydroxyethoxyphenyl) Propane-In the present invention, in addition to terephthalic acid, it is preferable to use isophthalic acid as the dicarboxylic acid component in an amount of 1 to 3 mol% based on the total amount of the dicarboxylic acid component. According to the present invention, a phosphorus compound and optionally at least one compound selected from a cobalt compound, a magnesium compound, and a manganese compound are added to a second or subsequent esterification vessel. (Please read the notice on the back before filling this page)

， 1T -line 丨. This paper size applies to Chinese National Standard (CNS) A4 (210X297mm) t 41 949 1 A7 B7 Printed by the Central Bureau of Quasi-Ministry of Economic Affairs, Shellfisher Consumer Cooperatives 11 V. Description of Invention 6) Examples of phosphorus compounds Includes phosphate esters, such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, and tricresyl phosphate: phosphites such as triphenyl phosphite, triphosphate (Dodecane) esters, and trinonyl phosphite; acid phosphates, such as acid methyl phosphate, acid isopropyl phosphate, butyl phosphate, dibutyl phosphate, monobutyl diacetate And dioctyl phosphate; phosphoric acid; and polyphosphoric acid. By adding a phosphorus compound to the esterification container, the color and thermal stability of the formed ethylene terephthalate can be improved. Examples of cobalt compounds include cobalt chloride, cobalt sulfate, cobalt hydroxide, cobalt nitrate, cobalt oxalate, cobalt formate, cobalt acetate, cobalt acetotriopropionate and cobalt osmate. By adding a cobalt compound to an esterification vessel, Can accelerate the esterification reaction. Examples of the manganese compound include manganese acetate, manganese acetate pyruvate, manganese sulfate, manganese carbonate, and manganese nitrate. By adding a manganese compound to the esterification vessel, the esterification reaction can be accelerated. Examples of magnesium compounds include sulfuric acid table, magnesium nitrate, magnesium acetate, chloride table, magnesium carbonate, magnesium citrate, magnesium lactate, and magnesium oxalate. ”By adding a magnesium compound to an esterification vessel, the esterification reaction can be accelerated. The aforementioned compounds are usually added as an aqueous solution or a glycol solution. When added as an aqueous solution, the amount of water is as low as possible. The amount of the phosphorus compound is expressed as a phosphorus atom and is usually 5 to 200 ppm as 1 mole of terephthalic acid ', preferably 10 to 100 ppm. The amount of cobalt compound is expressed as cobalt metal and is usually 5 to 200 ppm as 1 mole of terephthalic acid, preferably 10 to 60 ppm. The amount of manganese compound is expressed as manganese metal and as 1 mole of terephthalic acid (please (Read the meanings on the back, and then fill out this page)

, 1T This paper size is applicable to China® Home Standard (CNS) A4 specification (210 × 297 mm) -8 * Printing policy of Central Government Bureau of Standards, Shellfish Consumer Cooperative, 41 94 9 1 A? B7 V. Description of invention) Usually 1 0 to 200ppm 'is preferred at 20 to 1000ppm. The amount of magnesium compound is expressed in magnesium metal and is usually 5 to 200ppm in terms of 1 mole of terephthalic acid, preferably 15 to 50ppm. The foregoing compounds may be used simultaneously or Continuously added to the second or subsequent esterification vessel, preferably the second esterification vessel. Different from the prior art, in the present invention, the antimony compound as a polycondensation catalyst is fed into the first esterification vessel together with terephthalic acid and ethylene glycol in the form of a slurry, and phosphorus compounds and the like are added to the In the second or subsequent esterification vessel, it is difficult to precipitate antimony metal. In the previous technique, antimony compounds, phosphorus compounds, etc. were simultaneously fed into the esterification vessel. As a result, polyethylene terephthalate having excellent color and transparency can be obtained. The esterification reaction is carried out under reflux of ethylene glycol, and the water or alcohol formed by the reaction leaves the system by a fractionation column. The esterification reaction can be carried out under the following conditions: In the first stage of the esterification reaction, the temperature is usually 240 to 270 t, preferably 245 to 26 5 ° C, and the pressure is usually 0 · 2 to 3 kg / cm 2-G, with 0 ♦ 5 to 2 kg / cm 2-G is preferred; in the final stage of the esterification reaction, the temperature is usually 250 to 280 t, preferably 255 to 275 ° C, and the calendar power is usually 0 to 1.5 kg / cm 2-G. 0 to 1.3 kg / cm 2 —G is preferred. When the esterification reaction proceeds in two stages, the conditions of the first and second stages of the esterification reaction each fall within the aforementioned range of the first and last stages. When the esterification reaction is divided into three or more stages, 'except the first stage', the second to the most (please read the iir on the back of the page before filling out this page) (CNS) A4 specification (210X297 mm) -9- 4194 9 1 A 7 B7 Printed by the Consumer Cooperative Bureau of the Central Standards Bureau of the Ministry of Economic Affairs. 5. Description of the invention. Between the last stages For example, when the esterification reaction is carried out in three stages, the second stage esterification reaction is performed at a temperature of usually 2 4 5 to 2 7 5 ° C at a temperature of 2 50 to 2 7 0 ° C. Good—under normal pressure of 0 to 2 kg / cm G, 0 · 2 to 1 · 5kg / cm2—G is preferred. There is no specific limitation on the esterification conversion rate at each stage, but it is better to gradually increase the conversion rate in stages. The esterification conversion rate in the final stage is usually not less than 90%, and preferably not less than 93%. In the esterification reaction, a small amount of basic compounds such as tertiary amines such as trimethylamine, tri-n-butylamine and benzyldimethylamine, quaternary ammonium compounds such as tetraethylammonium hydroxide, Tetra-n-butylammonium hydroxide and trimethylammonium hydroxide, and other lithium carbonate, sodium carbonate, potassium carbonate and sodium acetate. It is preferable to add a tertiary compound to the esterification reaction because the proportion of the ethylene terephthalate component units in the polyethylene terephthalate main chain can be kept at a relatively low standard. The esterified product (low condensate) obtained through the aforementioned esterification reaction step usually has a number average molecular weight of 500 to 5,000 " The esterified product obtained previously is then dissolved in ethylene glycol with antimony compounds, phosphorus compounds, etc. The compounds added to the esterification vessel in this state are fed into a liquid-phase polycondensation reactor together. The liquid-phase polycondensation reaction is carried out at a temperature not lower than the melting point of the formed polyethylene terephthalate, under reduced pressure, in the presence of a polycondensation catalyst | by heating the system, and at the same time distilling off the reaction The formed diol "liquid phase polycondensation reaction can be carried out in a single stage or in multiple stages. National Standards (CNS) Α4 Specifications < 210 × 297 Gong) -10- Printed by Shellfish Consumer Cooperation Department of the Central Bureau of Standards of the Ministry of Economic Affairs 41 94 9 1 A7 _____B7____ 5. Description of the Invention 6) When the polycondensation reaction proceeds in multiple stages The first stage of the polycondensation reaction is usually at a temperature of 250 to 290 ° C-2 60 to 2 8 Ot, preferably 1 to 5 0 to 2 0 Torr pressure and 2 0 to 3 0 Torr is preferred to be carried out 'and the final polycondensation reaction is performed at a temperature of 2 65 to 300 tt and at a temperature of 2 70 to 295 ° C, preferably at a pressure of 10 to 0 to 1 torr. To 01 Torr is preferred, especially from 2 to 0.1 Torr. When the liquid-phase polycondensation reaction is carried out in two stages, the conditions of the first- and second-stage polycondensation reactions each fall within the ranges described in the aforementioned first and last stages. When the liquid-phase polycondensation reaction is carried out in three or more stages, in addition to the first stage, the polycondensation reaction conditions in the second to final stages are selected from the aforementioned first and last stages. For example, when the liquid-phase polycondensation reaction is carried out in three stages, the second-stage polycondensation reaction is performed at a temperature of usually 2 60 to 2 9 5 ° C, preferably 2 70 to 2 8 5 ° C, preferably 1 to 5 The pressure of 0 to 20 Torr is preferably performed at 40 to 50 Torr. The intrinsic viscosity (IV) of the polyethylene terephthalate prepared by the liquid-phase polycondensation reaction is not particularly limited, but it is preferable that the intrinsic viscosity is gradually increased in stages. The intrinsic viscosity of the polyethylene terephthalate obtained in the final polycondensation reaction is usually 0.35 to 0.80d «/ g, preferably 0.45 to 0.75df / g, and 0 55 to 0 · 75 d ί / g is better. The intrinsic viscosity (IV) can be calculated from the solution viscosity. It is measured at 25 ° C. By heating, 1.2 grams of polyethylene terephthalate is dissolved in 15 milliliters of o-chlorophenol. The viscosity of the resulting solution was cooled. The size of this paper is applicable to China National Standard (CNS) A4 (2! 〇X297mm);; Order ------ line _-(Please read the legal matters on the back before filling in this K) -11- 4194 91 Α7 Β7 Printed by the Consumer Cooperatives of the Central Bureau of Standards, Ministry of Economic Affairs 5. Description of the invention &) As mentioned above, the polyethylene terephthalate obtained through the liquid-phase polycondensation reaction may contain non-p-benzene The content of structural units derived from other dicarboxylic acids of dicarboxylic acid and structural units derived from other glycols other than ethylene glycol is not more than 20 mole%. Based on all dicarboxylic acid units, it is particularly preferred to contain from 1 to 3 mol% of structural units derived from isophthalic acid. Polyethylene terephthalate containing the aforementioned amount of isophthalic acid units is particularly excellent in color and transparency. In the present invention, it is desirable that the content of the ethylene terephthalate component unit of the following formula (I) is in the range of 95.0 to 99%, and the terephthalic acid represented by the following formula (II) The content of ethylene glycol dioxide is in the range of 1.0 to 5.0%: — (OOC- < ^)-C00CH2CH2i-… (I) eCoC- < ^ >-COOCH2CH2OCH2CH2r-… (Π) The polyethylene terephthalate obtained in the final liquid-phase polycondensation reactor is usually molded into pellets (flakes) by melt extrusion. It is desirable that the average diameter of the granular polyethylene terephthalate is generally 2.0 to 5.0 mm, preferably 2.2 to 4.0 mm. Ethylene glycol formate is then selectively subjected to a solid phase polycondensation reaction. The granular polyethylene terephthalate to be fed into the solid-phase polycondensation reactor can be crystallized in advance. The pre-crystallization is performed by heating the granular polyethylene terephthalate at a temperature lower than the temperature of the solid phase polycondensation reaction. In detail, (please read the precautions on the back before filling this page) 丨. This paper size applies to China National Standard (CNS) A4C (210X297 mm) -12- 41 94 9 1 A7 B7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs. 5. Description of the invention (0) Granular polyparaphenylene Ethylene glycol dicarboxylate is in a dry state 'at a temperature of usually 120 to 20 ° C, and heated at 1 30 to 1 80 ° C, preferably for 1 minute to 4 hours' or in water vapor, containing water vapor In an atmosphere of inert gas or steam containing air, 'heat at a temperature of usually 120 to 200 ° C for not less than 1 minute. The solid-phase polycondensation reaction includes at least one stage, at a temperature of usually 190 to 230 ° C and a temperature of 195 to 2 2 5 t, preferably a pressure of usually 1 kg / cmk G to 10 Torr. One is performed at atmospheric pressure to 100 Torr and preferably under an inert gas atmosphere such as nitrogen, argon or carbon dioxide gas. Of these inert gases, nitrogen is preferred. The polyethylene terephthalate obtained through the solid-state polycondensation reaction has an intrinsic viscosity usually not lower than 0 · 50 0 di / g, preferably not lower than 0 · 54cM / g, and not lower than 0.70di / g is better, not less than 0.72di / g, and has a density of usually not less than 1.37 g / cm3, preferably not less than 1.38g / cm3, not less than 1.39g / cm3 is better. It is desirable that the polyethylene terephthalate contains an oligomer (a cyclic terpolymer of the ethylene terephthalate component unit of the aforementioned formula (I)), and the content is not higher than 0.6% by weight, Not more than 0.5% by weight, more preferably not more than 0.45% by weight, not more than 0.4% by weight Very good " Secondly, the present invention is described in detail with reference to FIG. 1> FIG. Flow chart of an example of a process for inventing polyethylene terephthalate. In this specific example, the esterification reactor 2 is composed of the first esterification vessel 21, the second esterification vessel 22, and the third esterification vessel 23, and the liquid phase polycondensation reactor 3 Read the notes on the reverse side and fill in this page) The size of the paper used in this paper is Chinese National Standard (CNS) A4 (210X2? 7mm) -13- 4194 9 1 A7 ____B7 V. Description of the Invention 彳 彳) by the first A liquid-phase polycondensation container 31 and a second polycondensation container 32 are composed of 0 terephthalic acid, ethylene glycol, and an antimony compound as a catalyst, which are each fed into the mixer 1 through the feeding pipes 11, 12 and 13 to Preparation of slurry. In the slurry, terephthalic acid and antimony compounds are usually dispersed and suspended in ethylene glycol. The slurry is fed into the first esterification vessel 21 by a feed pump 17. The reaction product from the first esterification vessel 21 is then fed to the second esterification vessel 22, and the reaction product from the second esterification vessel 22 is fed to the third esterification vessel 23. In the first to third esterification vessels 21 to 23, each of the esterification reactions proceeds until the desired esterification conversion is achieved. The phosphorus compound and the selective cobalt compound are fed into the second esterification vessel 22 through the feed pipe? 4. The water formed by the esterification reaction is separated from the ethylene glycol by the fractionation column 15. The esterified product obtained above is continuously taken out from the third esterification vessel 23 by the pump 18, and then fed into the first liquid-phase polycondensation vessel 31. The reaction product in the first liquid-phase polycondensation container 31 is fed to the second liquid-phase polycondensation container. The staff of the Central Bureau of Standards, Ministry of Economic Affairs, Consumer Cooperation Du I n —Ml II J. I i I-..! 1 I— n --- i I: X 0¾-, T-. (Please read the precautions on the back before filling this page) 3 2 in. In the case of the first and second liquid-phase polycondensation vessels 3 1 and 32, the liquid-phase polycondensation reaction proceeds until the desired intrinsic viscosity is reached. The diol formed by the liquid-phase polycondensation is removed by the separator 16. The polyethylene terephthalate obtained from the second liquid-phase polycondensation reactor 32 was fed to an extruder 4 and molded into pellets. Granular polyethylene terephthalate is fed to a solid-phase polycondensation reactor 5 'where a solid-phase polycondensation reaction is performed. This paper size applies the Chinese National Standard (CMS) A4 specification (210X297 mm) -14- 41 94 9 1 A7 ______B7 V. Description of the invention < 2) Efficiency of the invention According to the method of the present invention, the antimony compound is used as a polycondensation catalyst in the ester It is mixed with terephthalic acid and ethylene glycol in the slurry state in the chemical container without dissolving in ethylene glycol beforehand. Therefore, there is no need for a special dissolution container, the number of steps can be reduced, and the device can be simplified, thereby reducing costs. In addition, it is not necessary to heat or keep the ethylene glycol to a high temperature to dissolve the antimony compound. Therefore, ethylene glycol is hardly destroyed, and the amount of di (ethylene glycol) formation is reduced. In addition, a slurry containing an antimony compound is fed to the first esterification vessel of many esterification vessels. Therefore, contamination with foreign substances and reduction in transparency caused by introducing an undissolved antimony compound into the polycondensation step did not occur. Department of Economics t Central Standards Bureau staff consumer cooperation Du I I- —rI In I * i -I ---.- _ -I-II 1 HI shame (please read the precautions on the back before filling this page) Moreover, an antimony compound is added in the first stage of the esterification step, and a phosphorus compound is added in the second or subsequent stage of the esterification step. As a result, antimony metal begins to precipitate, and the manufacture from polyethylene terephthalate reduces the number of steps and simplifies the device, reducing costs. In addition, it is not necessary to heat or maintain the ethylene glycol to dissolve the antimony compound. Therefore, ethylene glycol is hardly destroyed, and the amount of di (ethylene glycol) formed is reduced. In addition, a slurry containing an antimony compound is fed to a first esterification vessel of a plurality of esterification vessels. Therefore, contamination with foreign substances and reduction in transparency caused by introducing an undissolved antimony compound into the polycondensation step did not occur. Moreover, an antimony compound is added in the first stage of the esterification step, and a phosphorus compound is added in the second or subsequent stage of the esterification step. As a result, antimony metal began to precipitate, and bottles made from polyethylene terephthalate had superior paper sizes that were compatible with Chinese National Standard (CNS) A4 specifications (210X297 mm) -15- ί 41 94 9 1 Ministry of Economic Affairs Printed by the Central Standards Bureau ’s Consumer Cooperatives A7 _Β7_ V. Invention Description 彳 3) Color and transparency. Because the polyethylene terephthalate produced by the method of the present invention has good color and high transparency, it can be suitably used as a bottle for liquids such as beer, spirits and liquor, and for such as soy sauce and western spiced vinegar. And miso flavoring bottles, and bottles such as carbonated sauce, mineral water, fruit juice, green tea, coffee, and black tea. Examples The invention will be further described with reference to the following examples, but the invention is by no means limited to these Instance. Example 1 In a continuous polycondensation reaction device consisting of the first to fourth container-type reactors and the fifth horizontal twin-screw rotary reactor, the polycondensation system of ethylene glycol and terephthalic acid was continuous according to the following method Performed to prepare polyethylene terephthalate (PET). In a nitrogen atmosphere, a reaction solution containing 3,750 parts by weight at 255 ° C and 1-7 kg / cm2-G was placed in the first reactor. The slurry prepared by mixing high-purity terephthalic acid, ethylene glycol and antimony trioxide was continuously fed into the first reactor. The feed rate of high-purity terephthalic acid was 1, 4 3 7 weight per hour. Parts, and the feed rate of antimony trioxide is 0 * 5 7 parts by weight per hour for the first stage of the esterification reaction, during which 2 0 3 parts by weight per hour, 3 parts by weight of ethylene glycol per hour. The first-stage esterification reaction is controlled to make the average residence time of the slurry become I 1 --- --Ί ί HM.-T I 1 1--* I I.-1- J-I --- I ^. (Please Please read the notes on the back before filling this page) This paper size is in accordance with China National Standards (CNS) A4 Zhuge (210X297 mm) -16- i 41 94 9 1 Printed by the Consumer Cooperatives of the Central Procurement Bureau of the Ministry of Economic Affairs A7 B7_ V. Description of the invention ί 4) 2 hours. The slurry discharged from the first reactor was continuously introduced into the second reactor maintained at 26 ° C and 0 · 8kg / cm2—G with stirring. The second reactor was continuously fed with a homogeneous solution of 85% phosphoric acid and ethylene glycol, and 85% phosphoric acid was intercepted at a rate of 4 parts by weight per hour, and a rate of 9 parts by weight per hour. Feed ethylene glycol 'while continuously distilling water and glycol at a rate of 84 parts by weight per hour and 7 parts by weight per hour, so that the average residence time of the slurry becomes 2.0 hours. The slurry discharged from the second reactor was introduced into the third reactor maintained at 275 ° C and 70 mmHg with stirring. In the third reactor, ethylene glycol and water were continuously distilled off at a rate of 62 parts by weight per hour and at a rate of 6 parts by weight per hour to perform the first-stage polycondensation reaction and control the reactions to be mixed ' The average length of stay is 1.0 hours. The polycondensation reaction product discharged from the third reactor was continuously introduced into the fourth reactor maintained at 28 ° C and 5 mmHg under stirring. In the fourth reactor, each was 26 parts by weight per hour. Continuously distill off ethylene glycol and water at a rate and at a rate of 3 parts by weight per hour to carry out the second-stage polycondensation reaction, and control to make the average residence time of the reaction mixture become 1 * 0 hours. Unload from the fourth reactor The resulting polycondensation reaction product was continuously introduced into the fifth reactor (horizontal twin-screw rotary type reaction vessel) maintained at 282 to 285 ° C and 1 · 8 to 2 · 5 mmHg under stirring. 0 In the fifth reactor 1 Continuously distill off ethylene glycol and water at a rate of 12 parts by weight per hour and a rate of 1 part by weight per hour for reading (please read the precautions on the back before filling this page) This paper size applies Chinese national standards (CNS) A4 specification (210X297). -17- 41 94 9 1 A7 B7 V. Description of the invention 丨 5) The third stage polycondensation reaction is controlled to keep the average residence time of the polycondensation reaction product to 2_5 hours. The polycondensation reaction product was pulled out of the reactor in a cable form by a polyester puller. The cord was then immersed in water to cool it and cut with a cord cutter to obtain polyethylene terephthalate (PET) in the form of a sheet. The intrinsic viscosity of P E T obtained by the aforementioned liquid-phase polycondensation reaction was measured at 0 to 58 d! / G in o-chlorophenol at 25 ° C, and contained 0.995% by weight of a diethylene glycol unit. PET obtained by liquid phase polycondensation is then subjected to solid phase polycondensation in a nitrogen atmosphere at about 210 ° C. The intrinsic viscosity of the formed P ET was determined to be 0.79 di / g in o-chlorophenol at 25 ° C, and the density was 1.40 g / cm3. The content of diethylene glycol units in this PET was 0.96% by weight. PET was then molded in an injection molding machine (M-70A, manufactured by Meiki Seisakusho K.K.) at 290 ° C to obtain a stepped square molding. The turbidity of the molded product at a thickness of 4 mm was 55%, and the turbidity at a thickness of 5 mm was 14.3%. The step-shaped square molded article obtained by molding PET at 275 had an acetaldehyde content of 8 P pm. Printed by Shellfish Consumer Cooperative of the Central Bureau of Procurement, Ministry of Economic Affairs I · — ^^ 1 ^ J—-1 · 1 111 I--'. ^ Ϋ 1 ^ 1 ^^ 1', 1 • (Please read the note on the back first Matters to fill out this page) Example? !! PET was prepared according to the method of Example 1. The different parts were 1 ′ 3 9 4 parts by weight of high-purity terephthalic acid and 43 parts by weight of isophthalic acid instead of 1, 4 3 7 parts by weight of high-purity terephthalic acid. Dicarboxylic acid; the amount of antimony trioxide becomes 0.46 parts by weight, and the amount of 8 5% phosphoric acid becomes 0.20 parts by weight. The paper scale is applicable to the China National Standard (CNS) 8-4 specification (2 丨 〇 < 297 shovel-18- ^ 419491 A7 _B7_ V. Description of the invention < 6) of the PET (liquid phase polycondensation product) The intrinsic viscosity was measured in o-chlorophenol at 25 ° C as 0.60 di / g 'and PET (liquid-phase polycondensation product) containing 0. 98 parts by weight of diethylene glycol units was subsequently subjected to solidification as in Example 1. Phase condensation. The intrinsic viscosity of the formed P E T was measured at 0.85 cM / g in o-chlorophenol at 25 t, the density was 1. 40 g / cm3, and it contained 0.98% by weight of diethylene glycol units. This P E T was molded into a two-stage square molded article in the same manner as in Example 1. The turbidity of a molded article molded at 290 ° C is 4 · 2% at a thickness of 4 mm, and the turbidity is 7 · 5% at a thickness of 5 mm »The other is at 275 ° C The molded product had an acetaldehyde content of 8 p pm. Example 3 The PET was prepared according to the method of Example 2. The different places were that 0.10 parts by weight of 85% phosphoric acid was fed into a second reactor to replace 046 parts by weight of 85% phosphoric acid, and 0 was fed. -24 parts by weight of cobalt acetate tetrahydrate. Printed by the Consumers' Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the precautions on the back before filling this page). The intrinsic viscosity of the formed PET (liquid-phase polycondensation product) is measured at 0 ° C in o-chlorophenol as 0 * 65 di / g, while containing 0.99 parts by weight of diethylene glycol units "PET (liquid phase polycondensation product) was then subjected to solid phase polycondensation as in Example 1. The formed PET had an intrinsic viscosity of 0 · 88 d < / g and an density of 1. 40 g / cm 3 in o-chlorophenol at 25 ° C, and contained 1 to 0 1% by weight of a diethylene glycol unit. 》 This paper size applies to China's national standard (CNS > A4 size (210X297mm) -19- 41 94 9 1 A7 Printed by the Consumers ’Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs _B7 V. Invention Description 彳 7) The PET A two-stage square molded article was molded in the same manner as in Example 1. The turbidity of a molded article molded at 290 ° C at a thickness of 4 mm is 3.9%, and the turbidity of a molded article at a thickness of 5 mm is 6.9%. »Another molded product molded at 2 7 The acetaldehyde content was 9 p pm. Example 4 P ET was prepared according to the method of Example 1, except that the amount of antimony trioxide used was changed to 0.46 parts by weight and 0. 24 parts by weight of trimethyl phosphate was used instead of 8 5% phosphoric acid. The intrinsic viscosity of the formed PET (liquid-phase polycondensation product) was measured at 0.5 t in o-chlorophenol at 2.5 t / g and contained 1.02 parts by weight of ethylene glycol units. The phase polycondensation product) was then subjected to the solid phase polycondensation as in Example 1. The intrinsic viscosity of the formed P E T was measured at 0 ° 88 di / g in o-chlorophenol at 25 ° C., the density was 1. 40 g / cm 3 and it contained 1.03% by weight of diethylene glycol units. This P E T was molded into a two-stage square molded article in the same manner as in Example 1. The turbidity of a molded article molded at 290 ° C at a thickness of 4 mm is 6.0%, and the turbidity at a thickness of 5 mm is 1 3 _ 2%. The other molded article, which was molded at 27.5 ° C, had an acetaldehyde content of 10 ppm. Example 5 P ET was prepared according to the method of Example 3, which was used in different places-m Γ '·! ^ —--I III-I-^^ 1 In *-(Please read the precautions on the back before filling this page ) This paper size applies to Chinese national standards (CNS > A4 size (210X297 mm) -20- A7 Printed by the Consumer Cooperatives of the Central Bureau of Samples of the Ministry of Economic Affairs ______ B7 V. Invention Description 8) 1, 3 6 5 parts by weight High purity terephthalic acid and 72 parts by weight of isophthalic acid, and the amount of antimony trioxide used was 0.39 parts by weight. The formed PET (liquid phase polycondensation product) had an intrinsic viscosity of 0 60 di / g measured in o-chlorophenol at 25 t and contained 0.92 parts by weight of ethylene glycol units. PET (liquid phase polycondensation product) was then subjected to solid phase polycondensation as in Example 1. The formed PET has an intrinsic viscosity of 0 · 80 d! / G measured in o-chlorophenol at 25 ° C, a density of 1. 40 g / cm3, and contains 0.92% by weight of diethylene glycol units. . This P E T was molded into a two-stage square molded article in the same manner as in Example 1. The turbidity of a molded article molded at 290 ° C at a thickness of 4 mm was 3.4%, and the turbidity at a thickness of 5 mm was 4.7%. The other moulded product at 25 ° C had an acetaldehyde content of 10 p pm. Comparative Example 1 PET was prepared according to the method of Example 1, except that antimony trioxide was fed to the second reactor instead of the first reactor. The intrinsic viscosity of the formed P E T (liquid phase polycondensation product) was measured at 0 ° C to 57di / g in o-chlorophenol at 25 ° C and contained 0 97 parts by weight of ethylene glycol units. PET (liquid phase polycondensation product) was then subjected to solid phase polycondensation as in Example 1. The intrinsic viscosity of the PET formed was measured at 0.8 ° d / g in o-chlorophenol at 25 ° C, with a density of 1 * 40 g / cm3 and containing 0.97% by weight of diethylene glycol units. (Please read the precautions on the back before filling this page) The silver scale of this paper is applicable to the China National Park Standard {CNS > A4 Washer (2HJX297) -21-41 94 9 1 A7 B7 __——-- * --- 5. Description of the Invention 彳 9) The PET was molded into a two-stage square molded article in the manner of Example 1. 9 χχ: The turbidity of the molded article under molding at a thickness of 4 mm is 9.6%, and the turbidity at a thickness of 5 mm is 35.5%. Display is less transparent. In another molded article molded at 27.5 ° C, the acetaldehyde content was 7 p p 卬 °. Comparative Example 2 P E T was prepared according to the method of Example 2, except that 85% phosphoric acid was not fed. The formed PET (liquid-phase polycondensation product I) had an intrinsic viscosity of 0 * 66di // g 'measured in o-chlorophenol at 25 ° C and contained 0.995 parts by weight of ethylene glycol units. PET (liquid-phase polycondensation product) was subsequently subjected to the solid phase polycondensation as in Example 1. The intrinsic viscosity of the PET formed at 0 ° C was measured in o-chloro S & at 0 ° C. 'Density is 1.40 g / cm3' Contains 0.98% by weight of diethylene glycol units. Printed by the Central Standards Bureau of the Ministry of Economic Affairs, Shelley Consumer Cooperative. This PET was molded into a two-stage square molded product in the manner of Example 1. The turbidity of a molded article molded at 290 ° C at a thickness of 4 mm was 4.4%, and the turbidity at a thickness of 5 mm was 8 -1%. In another molded article molded at 27.5 t, the acetaldehyde content is 1 4 p pm 'The PET used has a high acetaldehyde content " Comparative Example 3 PET was prepared according to the method of Example 2, except that -22- (Please read the notes on the back before filling out this page) This paper size applies to China National Standard (CNS) A4 specification (210X25 »7mm)

AA 9A 9 A A7 __B7 V. Description of the invention ί) 〇 · 10 10 parts by weight 8 5% phosphoric acid is fed into the first reactor instead of the second reactor. The formed PET (liquid phase polycondensation product) had an intrinsic viscosity of 0 * 56 d / g measured in o-chlorophenol at 25 ° C and contained 0. 92 parts by weight of ethylene glycol units.

Order I indicates poor transparency. In another molded article molded at 275 t, the glyoxal content was 10 ppm.

I

I Brief description of the drawings

I Figure 1 illustrates the specific method for preparing the polyethylene terephthalate of the present invention 丨 printed by the Consumer Cooperative of the Central Bureau of the Ministry of Economic Affairs of the People's Republic of China --- FI --- Λ ------1 (please first Read the notes on the back of the page and fill in this page again.] PET (liquid phase polycondensation product) was then subjected to solid phase polycondensation as in Example 1. The intrinsic viscosity of the formed PET was measured as 0 in o-chlorophenol at 25 ° C. 80di / g, density 1.40g / cm3, and contains 0 * 95% by weight of diethylene glycol units. The PET was molded into a two-stage square molding in the manner of Example 1. At 2 9 The turbidity of the molded article molded at 0 ° C at a thickness of 4 mm is 10 * 1%, and the impulse at a thickness of 5 mm is 37.2%.

Example flow chart I 1: Mixer

J 2: Esterification reactor | 3: Liquid-phase polycondensation reactor 1 |

4: Extruder I 5: Solid-phase polycondensation reactor This paper size is applicable to China National Standard (CNS) A4 * t grid (2 丨 〇 < 297 mm) • 23-

Claims (1)

Printed Attachment (A) of Employee Cooperatives of Intellectual Property Bureau of the Ministry of Economic Affairs: Patent Application No. 86 1 1 2845 Chinese Application for Patent Scope Amendment Republic of China 8_9 June Amendment 1. A Convergence Pair in Polyester Preparation Device A method for producing ethylene phthalate, the device comprises an esterification reactor composed of a plurality of continuous esterification vessels, a liquid phase polycondensation reactor, and a selective solid phase polycondensation reactor. The method includes the following steps: Feed a slurry containing terephthalic acid, ethylene glycol and antimony compounds into the first esterification vessel; and add a phosphorus compound and optionally a second or subsequent esterification vessel selected from cobalt compounds, magnesium compounds and At least one compound 1 of a manganese compound, wherein the slurry contains a chain compound in terms of terephthalic acid of 150 to 400 p pm, wherein the slurry containing terephthalic acid, ethylene glycol, and an antimony compound is based on Prepared at a temperature of 0 to 50 ° C, and wherein the reaction temperature in the first esterification vessel is in the range of 2 40 to 2. 7 0 ° C. 2. The method for preparing polyethylene terephthalate according to item 1 of the scope of patent application, wherein the antimony compound is antimony trioxide-'3. For the polyethylene terephthalate according to item 1 or 2 of scope of patent application An alcohol ester production method in which the phosphating compound, cobalt compound and antimony compound are added in the form of an aqueous solution. 4. If the paper size of the polyethylene terephthalate of item 1 or 2 of the patent application is applicable to the Chinese National Standard (CNS) A4 specification (210 x 297 mm) ~ 7 ~ _ -------- ------ install -------- order --------- line * < please read the notes on the back before filling this page) 9 41 Λ 00 00829 ABCD Ministry of Economic Affairs Printed by the Intellectual Property Bureau's Consumer Cooperatives 6. Scope of Patent Application · Alcoholic Vinegar Production Method 'In addition to terephthalic acid, isophthalic acid is also used as the total amount of dixiang acid content of 1 to 3 mol% of isophthalic acid as the Dicarboxylic acid. — — — — — — — — — — — — — 1111111 *-— — — — — — — — (Please read the notes on the back before filling out this page) -2- This paper size applies to Chinese national standards ( CNS) A4 size (210 X 297 mm)