JP5211646B2 - Polyester manufacturing method - Google Patents

Description

  The present invention relates to a method for producing polyester. In particular, the present invention relates to an efficient production method having a high polycondensation rate.

  Polyesters typified by polyethylene terephthalate are excellent in mechanical properties, thermal properties, electrical properties, etc., so they are widely used in molded products such as fibers, films, sheets, bottles, etc. doing.

  High molecular weight polyesters used as packaging materials for bottles and the like are usually prepared by melt polycondensation, solid phase polymerization through esterification and / or transesterification of dicarboxylic acid and / or its ester-forming derivative and diol. Manufactured by condensation.

  In the polyester production method which is currently mainstream, in order to obtain a polyester prepolymer having a relatively high molecular weight, a horizontal type plug flow reactor equipped with a complicated stirring blade is used in the melt polycondensation step. In addition, the reaction time for solid phase polycondensation usually extends to over 10 hours. Therefore, there is a demand for an efficient manufacturing method that improves these. For example, many methods for producing polyesters characterized by subjecting a polyester prepolymer having a relatively low molecular weight to a solid phase polycondensation step have been disclosed.

  Patent Document 1 discloses a detailed examination result regarding the dependency of the solid phase polycondensation rate on the catalyst amount and the carboxyl end group content of the prepolymer. Here, the amount of carboxyl end groups of the prepolymer is changed by changing the charging ratio of terephthalic acid and ethylene glycol in the esterification reaction, and an excessive amount of ethylene glycol is added to the initial charging amount at a later stage of the reaction. Although it is adjusted by adding a catalyst after a partial vacuum is applied to the polycondensation step, there is no description of a specific implementation method. Moreover, this method is not necessarily a method suitable for the continuous melt polycondensation method.

  On the other hand, antimony catalysts, germanium catalysts, titanium catalysts and the like have been known for a long time as catalysts for advancing polycondensation reactions, and tungsten catalysts are also known to have polycondensation reaction activity (Patent Document 2, 3, 4, 5). However, such a tungsten catalyst is related to a melt polycondensation reaction, and the color tone of the obtained polyester is yellowish and not always satisfactory.

The increase in molecular weight due to the polycondensation reaction of polyester is usually advanced by two kinds of reactions. That is, an esterification reaction (dehydration condensation reaction) between a carboxyl group and an alcohol group, and an ester exchange reaction (dediol condensation reaction) between an ester bond and an alcohol group. Patent Document 6 discloses a technique for improving the solid phase polycondensation rate by paying attention to the ratio of the esterification reaction catalytic activity to the total of the esterification reaction catalytic activity and the transesterification reaction catalytic activity. However, the invention described in this document obtains a polyester prepolymer having a low terminal carboxyl group concentration, that is, a high terminal alcohol group concentration by advancing the esterification reaction as much as possible at the stage of melt polycondensation. However, this method is not always satisfactory in terms of the efficiency of the polycondensation reaction.

JP-A-55-133421 Japanese Patent Publication No. 44-19554 Japanese Examined Patent Publication No. 46-2517 Japanese Patent Publication No. 48-39235 JP-A-56-74123 JP 2006-265536 A

  An object of the present invention is to increase the production efficiency of polyester by providing a method for producing a high-molecular-weight and high-quality polyester in a short polycondensation time by increasing the polycondensation reaction rate of the polyester.

The present inventors pay particular attention to an increase in molecular weight due to the esterification reaction among the two kinds of reactions (esterification reaction, transesterification reaction) for increasing the molecular weight of the polyester described above, and using the esterification reaction catalyst, the esterification rate By controlling the ratio of the number of terminal carboxyl groups of the prepolymer to the total number of terminals within a specific range, the molecular weight can be increased by proceeding in a balanced manner between the esterification reaction and the transesterification reaction. As a result, the present invention has been found. That is, the gist of the present invention is as follows.
(1) An esterification step in which an oligomer is obtained by an esterification reaction using an esterification catalyst using a dicarboxylic acid component having an aromatic dicarboxylic acid as a main component and a diol component having an aliphatic diol as a main component as raw materials (a) ), A melt polycondensation step (b) for obtaining a prepolymer from the obtained oligomer by a melt polycondensation reaction, a granulation step (c) using the obtained prepolymer as prepolymer particles, and the obtained prepolymer particles A continuous polyester production method comprising a solid phase polycondensation step (d) for obtaining a polyester by a solid phase polycondensation reaction, wherein the polyester satisfies the following (1) to (4): Manufacturing method.
(1) The esterification rate of the esterification reaction product obtained in the esterification step (a) is 86% to 96%.
(2) Add at least one esterification catalyst to the melt polycondensation step (b) and / or the previous step.
(3) The ratio R0 of the number of terminal carboxyl groups to the total number of terminal groups of the prepolymer particles obtained in the granulating step (c) is 0.20 to 0.60, and the intrinsic viscosity is 0.25 dL / g to 0.00. 50 dL / g.
(4) The ratio R1 of the number of terminal carboxyl groups to the total number of terminal groups of the polyester obtained in the solid phase polycondensation step (d) and R0 satisfy the following (Formula 1), and the intrinsic viscosity is 0.7 dL / g to 1.5 dL / g.
(Formula 1) R0-R1 ≦ 0.1
(2) The method for producing a polyester according to (1), wherein a tungsten catalyst is used as the esterification catalyst.
(3) The method for producing a polyester according to (1) or (2), wherein a titanium catalyst is used as the esterification catalyst.
(4) R0 and R1 satisfy | fill following (Formula 2), The manufacturing method of polyester of any one of (1)-(3) characterized by the above-mentioned.
(Formula 2) −0.2 ≦ R0−R1
(5) The method for producing a polyester according to any one of (1) to (4), wherein a tungsten catalyst and a titanium catalyst are added in this order as an esterification catalyst.
(6) The raw material preparation step prior to the esterification step (a), and the oligomer transfer step between the esterification step (a) and the melt polycondensation step (b), and the tungsten catalyst is converted into the esterification step (a) And / or adding in the raw material preparation step, and further adding a titanium catalyst to the melt polycondensation step (b) and / or the previous step.
(7) The method for producing a polyester according to any one of (1) to (4), wherein a titanium catalyst and a tungsten catalyst are added in this order as an esterification catalyst.
(8) having a raw material preparation step prior to the esterification step (a), adding a titanium catalyst to the esterification step (a) and / or the raw material preparation step, and further adding a tungsten catalyst to the melt polycondensation step (b) and / or Alternatively, the polyester production method according to (7), which is added to the previous step.
(9) The polyester production method according to any one of (1) to (8), wherein the average mass of the prepolymer particles is 1.0 mg / grain to 50 mg / grain.
(10) The method for producing a polyester as described in any one of (1) to (9), wherein the content of antimony atoms in the polyester is 10 mass ppm or less.

  According to the present invention, it is possible to produce a high-quality polyester having a high molecular weight, a uniform shape, and a low content of antimony atoms in a short polycondensation time.

Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

The method for producing a polyester according to the present invention comprises a dicarboxylic acid component having an aromatic dicarboxylic acid as a main component and a diol component having an aliphatic diol as a main component as raw materials, and an oligomer formed by an esterification reaction using an esterification catalyst. The obtained esterification step (a), the melt polycondensation step (b) for obtaining a prepolymer from the obtained oligomer by a melt polycondensation reaction, the granulation step (c) using the obtained prepolymer as prepolymer particles, and the obtained And a solid phase polycondensation step (d) for obtaining a polyester by solid phase polycondensation reaction of the obtained prepolymer particles, which satisfies the following (1) to (4): This is a method for producing polyester.
(1) The esterification rate of the esterification reaction product obtained in the esterification step (a) is 86% to 96%.
(2) An esterification catalyst is added to the melt polycondensation step (b) and / or the previous step.
(3) The ratio R0 of the number of terminal carboxyl groups to the total number of terminal groups of the prepolymer particles obtained in the granulating step (c) is 0.20 to 0.60, and the intrinsic viscosity is 0.25 dL / g to 0.00. 50 dL / g.
(4) The ratio R1 of the number of terminal carboxyl groups to the total number of terminal groups of the polyester obtained in the solid phase polycondensation step (d) and R0 satisfy the following (formula 1), and the intrinsic viscosity is 0.7 dL / g to 1.5 dL / g.
(Formula 1) R0-R1 ≦ 0.1
Here, the continuous production method means that the production is continued under substantially constant conditions without interrupting the product.

The polyester production method of the present invention is preferably a raw material preparation step in which a dicarboxylic acid component and a diol component are mixed to obtain a slurry, a slurry transfer step in which the obtained slurry is transferred to an esterification step, and the transferred slurry is esterified An esterification step (a) for obtaining an esterification reaction product (oligomer) by reaction, an oligomer transfer step for transferring the obtained oligomer to a melt polycondensation step, and a polyester prepolymer by subjecting the transferred oligomer to a melt polycondensation reaction A melt polycondensation step (b), a prepolymer transfer step for transferring the obtained prepolymer to a granulation step, a granulation step (c) for granulating the transferred prepolymer to obtain prepolymer particles, A solid phase polycondensation step (d) for obtaining a polyester by subjecting the prepolymer particles to a solid phase polycondensation reaction.

  In the present invention, “having an aromatic dicarboxylic acid as a main component” usually means that 95 mol% or more is an aromatic dicarboxylic acid component with respect to all dicarboxylic acid components used for producing polyester, preferably Is 97 mol% or more. If content of an aromatic dicarboxylic acid component is less than the said range, it exists in the tendency for the heat resistance as molded objects, such as a heat-resistant bottle, to be inferior. The term “mainly comprising an aliphatic diol” usually means that the aliphatic diol component is 95 mol% or more, preferably 97 mol% or more, based on the total diol components used for producing the polyester. It is.

Examples of the aromatic dicarboxylic acid include terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4 , 4′-diphenyl ketone dicarboxylic acid, 4,4′-diphenoxyethane dicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid and the like. Of these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred because they provide a polyester with good heat resistance. Furthermore, terephthalic acid is particularly preferred because of its industrial availability.
Here, examples of the dicarboxylic acid component other than the aromatic dicarboxylic acid include alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid. And aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, undecadicarboxylic acid, and dodecadicarboxylic acid.

Examples of the aliphatic diol component include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl- Aliphatic diols such as 1,3-propanediol, diethylene glycol, polyethylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexane Examples include alicyclic diols such as dimethylol and 2,5-norbornane dimethylol.
Among these, ethylene glycol and tetramethylene glycol are preferable, and ethylene glycol is particularly preferable.

  Diols other than aliphatic diols include xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, and 2,2-bis (4′-β-hydroxyethoxyphenyl). Aromatic diols such as propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and ethylene oxide adducts of 2,2-bis (4′-hydroxyphenyl) propane or Examples thereof include propylene oxide adducts, and two or more of these may be used as components.

  Furthermore, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid Monofunctional components such as benzoylbenzoic acid, trifunctional or more polyfunctional components such as tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, etc. 1 type, or 2 or more types may be used as a copolymerization component.

In the present invention, at least one esterification catalyst is added in the melt polycondensation step (b) and / or the previous step. Here, the esterification catalyst is a compound that, when added to the reaction system, promotes the esterification reaction more than when it is not added. Specifically, benzenesulfonic acid, toluenesulfonic acid, sulfuric acid, nitric acid, A compound containing a Bronsted acid such as phosphoric acid or a partially neutralized product thereof, and a metal selected from alkali metals, alkaline earth metals, antimony, germanium, aluminum, zinc, tin, manganese, cobalt, titanium, and tungsten. Can be mentioned. Among them, a titanium catalyst which is a compound or mixture containing titanium and / or a compound containing a titanium having a high catalytic activity and good color tone of the resulting polyester and / or a tungsten catalyst which is a compound or mixture containing tungsten is preferable. Since the antimony catalyst which is a compound or mixture containing antimony is liable to generate foreign matter in the polyester, the content of the polyester is preferably 10 ppm by mass or less of antimony atoms.
Examples of titanium catalysts include tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate, acetyl-tri-i-propyl. Tetraalkoxy titanates such as titanate, titanium-containing compounds such as titanium acetate, titanium oxalate, and titanium chloride, as well as alcohols, alkaline earth metal compounds, phosphate ester compounds, and the aforementioned tetraalkoxy titanates, titanium acetate, titanium oxalate, titanium chloride Examples thereof include liquid materials obtained by mixing two or more of titanium-containing compounds such as the above. Among these titanium catalysts, it is preferable to contain tetra-i-propyl titanate and / or tetra-n-butyl titanate, and tetra-n-butyl titanate, alcohol, alkaline earth metal compound and phosphate ester compound are mixed. The liquid obtained by this is more preferable. The total amount added to the melt polycondensation step (b) and / or the previous step is usually 1 ppm to 20 ppm by mass as the amount of titanium metal atoms relative to the polyester obtained, and 4 ppm to 10 ppm by mass. preferable.
Examples of the tungsten catalyst include tungsten trioxide, paratungstic acid, metatungstic acid, tungstic acid, silicotungstic acid, phosphotungstic acid, and salts thereof. Among them, ammonium metatungstate, ammonium paratungstate, tungsten Sodium acid and tungstic acid are preferred, and ammonium metatungstate and ammonium paratungstate are more preferred. These tungsten catalysts may use only 1 type and may use 2 or more types. The total amount added to the melt polycondensation step (b) and / or the previous step is usually 10 mass ppm to 150 mass ppm, and 20 mass ppm to 100 mass ppm as the amount of tungsten metal atoms relative to the obtained polyester. Is more preferable.
Here, adding the esterification catalyst to the melt polycondensation step (b) and / or the previous step is a raw material preparation step in which a slurry is obtained by mixing a dicarboxylic acid component and a diol component, and the resulting slurry is esterified. Add to the slurry transfer step to transfer to the conversion step, the esterification step to esterify the transferred slurry to obtain the esterification reaction product (oligomer), the oligomer transfer step to transfer the resulting oligomer to the melt polycondensation step, etc. In particular, it is preferably added to the oligomer transfer step.

  In the production method of the present invention, the esterification rate of the esterification reaction product (oligomer) obtained in the esterification step (the ratio of those esterified by reacting with the diol component out of all the carboxyl groups of the raw material dicarboxylic acid component) is: The lower limit is 86%, preferably 92%, and the upper limit is 96%, preferably 95%. When the esterification rate is less than the lower limit, the terminal carboxyl group is relatively excessive, and the polycondensation reaction reaches its peak, which is not preferable. If the esterification rate exceeds the upper limit, the transesterification reaction becomes dominant in the subsequent polycondensation step, which is not preferable because the effects of the present invention are not sufficiently exhibited.

  In the present invention, the ratio R0 of the number of terminal carboxyl groups to the total number of terminal groups of the prepolymer obtained in the granulation step (c) is 0.20 to 0.60. The lower limit of R0 is preferably 0.25, and the upper limit is preferably 0.55. When R0 is less than the lower limit, the solid phase polycondensation reaction needs to proceed at the transesterification reaction center, and the effect of the present invention is not sufficiently exhibited, which is not preferable. When R0 exceeds the upper limit, the terminal carboxyl group is relatively excessive and the polycondensation reaction reaches its peak, which is not preferable. The intrinsic viscosity of the prepolymer obtained in the granulation step (c) is 0.25 dL / g to 0.50 dL / g, and the lower limit is preferably 0.28 dL / g, more preferably 0.30 dL / g, and the upper limit. Is preferably 0.48 dL / g, more preferably 0.46 dL / g.

In the present invention, the ratio R1 of the number of terminal carboxyl groups to the total number of terminal groups of the polyester obtained in the solid phase polycondensation step (d) and R0 satisfy (Equation 1), and the intrinsic viscosity is 0.7 to 1.5 dL. / G.
(Formula 1) R0-R1 ≦ 0.1
The upper limit of R0-R1 is preferably 0.05, more preferably 0.03. The lower limit of R0-R1 is preferably -0.5, more preferably -0.3, and still more preferably -0.2. When R0-R1 is less than the lower limit, the ratio of the transesterification reaction is high in the solid phase polycondensation step (d). Therefore, particularly in the case of a reaction mode having a high layer height such as a moving bed reactor, The influence of the phase polycondensation rate reduction may become large. When R0-R1 exceeds the upper limit, the terminal alcohol group becomes relatively excessive during the solid phase polycondensation reaction, and the effects of the present invention are not sufficiently exhibited, which is not preferable.

The esterification rate can be controlled by the reaction time and temperature in the esterification step.
R0 can be controlled by the reaction time, temperature, pressure, mixed state, etc. in the melt polycondensation step.
R1 can be controlled by the reaction time, temperature, concentration of water and diol component in the atmosphere in the solid phase polycondensation step.
Furthermore, since the esterification rate, R0 and R1 are also affected by the activity and selectivity of the esterification catalyst to be added, it can be controlled by selecting the type of esterification catalyst and the timing of addition.
In the present invention, it is particularly preferable to add a tungsten catalyst and a titanium catalyst sequentially as the esterification catalyst. The tungsten catalyst is added in the esterification step (a) and / or the raw material preparation step, and further the titanium catalyst is melt polycondensation step. (B) and / or added to the previous step, or a titanium catalyst is added to the esterification step (a) and / or the raw material preparation step, and a tungsten catalyst is further added to the melt polycondensation step (b) and / or It can be preferably controlled by adding to the previous step.

  If the esterification rate, R0, R1, and the intrinsic viscosity of the prepolymer are within the above ranges, the esterification reaction by the esterification reaction catalyst is promoted and there is no need to react to a high reaction rate. The polycondensation reaction is fast and very efficient as a whole.

  The intrinsic viscosity of the polyester obtained through the solid phase polycondensation step (b) of the present invention is 0.70 dL / g to 1.5 dL / g. A preferable lower limit is 0.75 dL / g or more. A preferable upper limit is 1.00 dL / g or less. If it is less than the lower limit, the mechanical strength of a molded article such as a bottle made from the raw material is inferior, which is not preferable. On the other hand, if the upper limit is exceeded, the melt viscosity may be too high during molding of the molded body, which may cause molding defects.

  The polyester production method of the present invention usually involves mixing a dicarboxylic acid component and a diol component when producing a polyester from a dicarboxylic acid component having an aromatic dicarboxylic acid as a main component and a diol component having an aliphatic diol as a main component. Raw material preparation step for obtaining a slurry, slurry transfer step for transferring the obtained slurry to an esterification step, esterification step (a) for obtaining an esterification reaction product (oligomer) by esterifying the transferred slurry, An oligomer transfer step for transferring the obtained oligomer to a melt polycondensation step, a melt polycondensation step (b) for obtaining a polyester prepolymer by subjecting the transferred oligomer to a melt polycondensation reaction, and the resulting prepolymer for a granulation step Prepolymer transfer process to transfer, granulate the transferred prepolymer to obtain prepolymer particles Granulation step (c), with a solid phase polycondensation step for obtaining a polyester by obtained prepolymer particles solid phase polycondensation reaction (d). Hereinafter, the production method will be specifically described by taking terephthalic acid as the aromatic dicarboxylic acid and ethylene glycol as the diol as an example, but the present invention is not limited thereto.

Raw material preparation step In the present invention, the raw material slurry is prepared by adding a dicarboxylic acid component containing terephthalic acid as a main component, a diol component containing ethylene glycol as a main component, and a copolymerization component used as necessary. The molar ratio of the diol component to the component is usually prepared as 1.0 to 2.0. This molar ratio is preferably 1.05 to 1.8, and more preferably 1.1 to 1.6.

Slurry transfer process, esterification process (a)
Subsequently, the prepared raw material slurry is transferred to an esterification step equipped with one or a plurality of continuous esterification reaction tanks, and is subjected to esterification reaction under normal pressure to pressure and under heating to obtain a polyester low molecular weight product. Let it be an oligomer.

As reaction conditions in the esterification reaction, in the case of a single esterification reaction tank, the temperature is usually 240 ° C. to 295 ° C., the pressure is usually 0 kPaG to 400 kPaG, and the reaction is usually performed for 1 hour to 10 hours with stirring. Time (residence time).
In the case of a plurality of esterification reaction tanks, the reaction temperature in the first stage esterification reaction tank is usually 240 ° C. to 295 ° C., preferably 245 ° C. to 293 ° C., and the pressure is usually 5 kPaG to 300 kPaG, preferably Is 10 kPaG to 200 kPaG, the reaction temperature in the final stage is usually 250 ° C. to 295 ° C., preferably 255 ° C. to 293 ° C., and the pressure is usually 0 kPaG to 150 kPaG, preferably 0 kPaG to 130 kPaG. Here, kPaG represents relative pressure with respect to atmospheric pressure in kPa units. The total residence time is usually 1 to 10 hours, preferably 1.2 to 5 hours.

  In the present invention, the esterification rate of the oligomer as the esterification reaction product is as described above.

Melt polycondensation step (b)
Subsequently, the obtained oligomer is transferred to a melt polycondensation step equipped with a polycondensation reaction tank, and subjected to a melt polycondensation reaction under reduced pressure and heating.

  In the present invention, since the intrinsic viscosity of the polyester prepolymer obtained by melt polycondensation is as low as 0.50 dL / g or less, a horizontal plug flow type second-stage polycondensation reaction tank equipped with a stirring blade that is often used conventionally and The third-stage polycondensation reaction tank is not necessarily required, and the melt polycondensation process is simplified and the equipment cost is reduced. In particular, the production method of the present invention can produce a high-molecular-weight polyester with a simpler equipment as compared with the conventional production method in the case of one melt polycondensation reaction tank.

  The reaction conditions in the melt polycondensation are a reaction temperature of usually 260 to 290 ° C, preferably 270 ° C to 280 ° C, and a pressure of usually 50 kPaA to 0.1 kPaA, preferably 40 kPaA to 0.1 kPaA. Here, kPaA represents the absolute pressure in kPa.

Prepolymer transfer process, granulation process (c)
The resin obtained by the melt polycondensation is usually extracted in a strand form from an extraction port provided at the bottom of the polycondensation reaction tank, and is cooled with water or after water cooling and then cut with a cutter to obtain polyester prepolymer particles. . Alternatively, while discharging and cooling into the water from the extraction port provided at the bottom of the polycondensation reaction tank, it is cut with a cutter that has a rotating shaft in a direction substantially parallel to the discharge direction and is installed adjacent to the leading end of the extraction port. Polyester prepolymer particles. Alternatively, the particles can be pulverized by a pulverizer to obtain particles having a desired average mass. The average mass of the prepolymer particles is usually 0.2 mg / grain to 50 mg / grain, and the lower limit is preferably 0.5 mg / grain, more preferably 1.0 mg / grain. The upper limit is preferably 30 mg / grain, more preferably 20 mg / grain. When the average mass of the prepolymer particles is within this range, the solid phase polycondensation rate is high, and handling such as aerodynamic transportation is easy, which is more preferable.

Crystallization Step The polyester prepolymer after particle formation is usually crystallized. Crystallization can be performed by a known method described in Japanese Patent No. 3073498, for example, by fluidizing in an inert gas stream at 120 ° C. to 180 ° C. for 0.5 to 12 hours. It can be carried out. By performing crystallization, the effect that the fusion | bonding of the pellets in the subsequent heat processing process can be prevented is acquired.

Heat treatment In the present invention, heat treatment may be performed on the polyester prepolymer after particle formation or after the prepolymer is crystallized. By performing the heat treatment, the prepolymer is subjected to solid-phase polycondensation and is easily increased in molecular weight. The heat treatment can be performed by a known method described in, for example, a pamphlet of WO 2007/026411, for example, in a moving bed reactor, polyester is continuously moved from the top to the bottom, and heated inert gas is continuously flowed from the bottom to the top. This can be done by pouring it through.

Solid phase polycondensation step (d)
In the present invention, the polyester prepolymer after particle formation is subjected to solid phase polycondensation after crystallization and / or heat treatment, if necessary. In the solid phase polycondensation reaction, the lower limit of the temperature is preferably 200 ° C, more preferably 205 ° C, and further preferably 208 ° C. The upper limit of the temperature is preferably 5 ° C. lower than the melting point of the polyester, more preferably 8 ° C. lower than the melting point, more preferably 10 ° C. lower than the melting point in an inert gas atmosphere. Here, the melting point of polyester is the highest temperature in the DSC curve when the polyester is heated from 0 ° C. to 300 ° C. at a rate of 20 ° C./min under a nitrogen stream using a differential scanning calorimeter. It is the temperature corresponding to the apex of the endothermic peak on the side. Moreover, an inert gas is a gas which oxygen concentration is 0.1 volume% or less normally, Preferably it is 0.05 volume% or less, and does not react with polyester substantially. Examples of the gas that does not substantially react with the polyester include nitrogen, helium, neon, argon, xenon, carbon dioxide and the like, and nitrogen is preferably used mainly from the viewpoint of economy.

  If the solid phase polycondensation temperature is low, the solid phase polycondensation rate is slow, which is not preferable. A high solid phase polycondensation temperature is not preferable because the polyester particles are fused during solid phase polycondensation. In particular, when the average mass of the polyester prepolymer particles is 0.1 mg / grain or less, solid phase polycondensation is preferably performed in a fluidized bed in order to avoid fusion. The solid phase polycondensation time may be set according to the target intrinsic viscosity, and is usually about 1 to 50 hours. The average mass after the solid phase polycondensation is generally almost the same as the average mass of the prepolymer particles before the solid phase polycondensation.

  The polyester obtained by the production method of the present invention can be made into a bottle used for beverage packaging or the like by stretch blow molding after forming a preform by injection molding or extrusion molding. Moreover, it can be made into a bottle by direct blow molding.

  Moreover, it can be used for various uses, such as a packaging material, by making into a film and a sheet | seat by extrusion molding and extending | stretching molding. Moreover, it can be set as a fiber by extrusion and drawing.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In addition, the measurement of the physical property in an Example and a comparative example was performed with the following method.
<Intrinsic viscosity (hereinafter also referred to as “IV”)>
About 0.25 g of the sample is mixed with about 25 mL of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (mass ratio: 1/1) so that the concentration becomes 1.00 × 10 ⁻² kg / L. The polyester in the amorphous state was 110 ° C. for 30 minutes, and the polyester after solid phase polycondensation was dissolved in 140 ° C. and 30 minutes, respectively, cooled to 30 ° C., and fully automatic solution viscometer (manufactured by Sentec Co., Ltd., With 2CH type DJ 504), the sample solution having a concentration of 1.00 × 10 ⁻² kg / L and the number of falling seconds of the solvent alone were measured and calculated by the following equation.
IV (dL / g) = [(1 + 4K _H · η _sp ) ^0.5 −1] / (200K _H · C)
Where η _sp = η / η ₀ −1, η represents the sample solution drop seconds, η ₀ represents the solvent drop seconds, C represents the polymer solution concentration (kg / L), K _H is a Haggins constant.
In this embodiment, K _H adopted the 0.33.

<Average mass of polyester prepolymer particles>
Using a precision balance, the total mass of 30 polyester prepolymer particles was measured to the order of 0.1 mg, and the measured value was divided by 30 to calculate the average mass per particle.

<Terminal carboxyl group concentration (hereinafter also referred to as “AV”)>
After pulverizing the sample, it was dried at 140 ° C. for 15 minutes in a hot air dryer, and 0.1 g was accurately weighed out from the sample cooled to room temperature in a desiccator, and 3 mL of benzyl alcohol was added, The solution was dissolved at 195 ° C. for 3 minutes while blowing dry nitrogen gas, and then 5 mL of chloroform was gradually added and cooled to room temperature. 1 to 2 drops of phenol red indicator was added to this solution, and titrated with 0.1N sodium benzyl alcohol solution of sodium hydroxide under stirring while blowing dry nitrogen gas, and when the color changed from yellow to red, the procedure was terminated. . Moreover, the same operation was implemented as a blank, without using a polyester sample, and the terminal carboxyl group density | concentration was computed by the following formula | equation using these results.
AV (equivalent / ton) = (A−B) × 0.1 × f / W
Here, A represents the amount (μL) of 0.1N sodium hydroxide in benzyl alcohol solution required for titration when a sample was used, and B required for titration with a blank to which no sample was added. This represents the amount (μL) of 0.1 N sodium hydroxide in benzyl alcohol solution, W represents the amount (g) of the polyester sample, and f is the force of 0.1 N sodium hydroxide in benzyl alcohol solution. Represents the value.
The titer (f) of a 0.1 N sodium hydroxide solution in benzyl alcohol was determined by taking 5 mL of methanol into a test tube and adding 1 to 2 drops of a phenol red ethanol solution as an indicator. Titrate with 0.4 mL of benzyl alcohol solution of sodium hydroxide to the discoloration point, then add 0.2 mL of 0.1 N hydrochloric acid with a known titer as a standard solution and add it again. The solution was titrated with a sodium benzyl alcohol solution to the discoloration point (the above operation was performed while blowing dry nitrogen gas), and calculated according to the following equation.
Titer (f) = 0.1 N hydrochloric acid titer × 0.1 N hydrochloric acid collected (μL) /0.1 N sodium hydroxide in benzyl alcohol solution titration (μL)

<Total end group concentration of polyester (hereinafter also referred to as “TEV”)>
The total terminal group concentration (TEV) of the polyester was calculated from the intrinsic viscosity (IV) by the following formula.
Calculate the number average molecular weight Mn from IV (dL / g) by the following formula:
Mn = (IV × 10000 / 7.55) ^ (1 / 0.685)
TEV (equivalent / ton) is calculated from Mn by the following formula.
TEV = 2 × (1000000 / Mn)

<Ratio of the number of terminal carboxyl groups to the total number of terminal groups (R)>
R = AV / TEV.

<Example 1>
The preparation method of the esterification catalyst used for esterification and / or polycondensation reaction is shown below.
<Tungsten catalyst (catalyst)>
Ammonium metatungstate aqueous solution (trade name: MW-2, manufactured by Nippon Inorganic Chemical Industries, Ltd., concentration of 50% by mass as tungsten trioxide (WO ₃ )) is diluted with ethylene glycol, and the tungsten atom concentration is 0.2% by mass. A catalyst solution (tungsten catalyst) was prepared.

<Titanium catalyst>
(Synthesis of catalyst solution having a molar ratio of Ti / Mg / P = 1/1 / 1.2)
In an Erlenmeyer flask with a 300 mL stopper, put 50 g of ethanol (special grade, purity 99.6% or more), then add 7.51 g of magnesium acetate tetrahydrate, stir with a stirrer for 20 minutes, It was dissolved uniformly. Next, 2.95 g of ethyl acid phosphate (trade name: JP-502, manufactured by Johoku Chemical Co., Ltd., mass ratio of monoester to diester) is added and stirred for 5 minutes, and further dibutyl phosphate ( (Product name: DBP, Johoku Chemical Co., Ltd.) 4.41 g was added and stirred for 5 minutes. Subsequently, 11.91 g of tetra-n-butyl titanate was added and stirred for 10 minutes to obtain a uniform solution. Ethylene glycol (36.1 g) was added to the resulting mixture, then transferred to a 300 mL eggplant flask and set in an evaporator. Ethanol and low boiling point were distilled off under conditions of 60 ° C. and 11 kPaA to obtain 47.9 g of homogeneous mixture. A transparent catalyst solution (titanium catalyst) was prepared. The ratio of each metal component in the titanium catalyst solution was Ti / Mg / P = 1/1 / 1.2 (molar ratio), and the titanium concentration was 3.5% by mass.

<Manufacture of polyester>
The method for producing polyester is shown below.
(Production of polyester prepolymer and prepolymerization of prepolymer)
Slurry preparation tank equipped with stirrer, ethylene glycol feed pipe and terephthalic acid feed pipe; each pipe for transferring slurry and esterification reaction product to each esterification reaction tank; stirrer, separation tower, raw material receiving port, catalyst feed pipe A fully mixed type first esterification reaction tank and a second esterification reaction tank equipped with an ethylene glycol charging pipe and a reactant transfer pipe; a pipe for transferring the esterification reaction product (oligomer) to the melt polycondensation reaction tank; A fully mixed type first melt polycondensation reaction tank having a separation tower, an oligomer receiving port and a prepolymer outlet; a plug flow type second melt weight having a stirrer, a separation tower, a prepolymer receiving port and a polymer outlet Condensation reaction tank and third melt polycondensation reaction tank: Draw the prepolymer from the die through the gear pump Particle apparatus for cooling with water strand cutting extraction into strands (strand cutter Rieter-automatic Co., pelletizer, P-USG100) using a polyester prepolymer continuous production apparatus equipped with.

Using the polyester prepolymer continuous production apparatus, terephthalic acid and ethylene glycol are esterified, and the melted polycondensation obtained by melt polycondensation is taken out from the die plate into strands and cut. Thus, polyester prepolymer particles were produced. Specifically, it was performed as follows.
In a slurry preparation tank, a slurry of terephthalic acid / isophthalic acid / ethylene glycol (molar ratio, 0.985: 0.015: 1.5) was prepared. In addition, 400 parts by mass of bis- (β-hydroxyethyl) terephthalate was charged into the first esterification tank, melted in a nitrogen atmosphere, and maintained at a temperature of 262 ° C. and a pressure of 92 kPaG. The slurry was continuously charged at 135 parts by mass / hour so that the average residence time as polyester was 4.6 hours, and the esterification reaction was carried out while distilling off the water produced from the separation tower. Was continuously transferred to the esterification second reaction vessel.
In the second esterification reaction tank, the temperature was set to 260 ° C. and the pressure was set to 3.5 kPaG, and the tungsten catalyst prepared above was continuously added in an amount of 40 mass ppm as tungsten to the polyester prepolymer obtained. Further, the esterification reaction was carried out with an average residence time of 1.9 hours while continuously adding ethylene glycol at a rate of 4 parts by mass / hour. The esterification rate of the reactant sample at the outlet of the second esterification reactor in the steady state was 95.6%.
Subsequently, it is continuously transferred to the fully mixed first melt polycondensation reaction tank through the transfer pipe, and at the same time, the titanium catalyst prepared above is transferred to this transfer pipe with respect to the obtained polyester prepolymer, titanium, magnesium, It added continuously so that phosphorus might be 4 mass ppm, 2 mass ppm, and 3.1 mass ppm, respectively.
In the first melt polycondensation reaction tank, the reaction was carried out at a temperature of 270 ° C. and a pressure of 3 kPaA with an average residence time of 1.5 hours, and continuously transferred to the second melt polycondensation reaction tank through a transfer pipe.
In the second melt polycondensation reaction tank, the melt polycondensation reaction was carried out at a temperature of 270 ° C. and a pressure of 3 kPaA with an average residence time of 1.0 hour, and transferred to the third melt polycondensation reaction tank through a transfer pipe.
In the third melt polycondensation reaction tank, the melt polycondensation reaction was performed at a temperature of 270 ° C. and a pressure of 3 kPaA with an average residence time of 0.5 hours.

The molten polyester prepolymer obtained above was directly led to a die head through a gear pump and an extraction pipe, taken out in a strand form from the die hole, cooled with water, and granulated with a pelletizer, P-USG100, manufactured by Reuter Automatic. The granulation method is a strand cutting method. Specifically, while the strand-shaped polyester prepolymer is brought into contact with water and cooled, it is conveyed in the direction of the cutter together with water, and a pair of take-up rolls installed in front of the cutter. The polyester prepolymer particle was obtained by picking up by pinching, supplying to a cutter, and cutting | disconnecting with the cutter which has a fixed blade and a rotary blade.
The obtained polyester prepolymer particles had a substantially uniform shape with an elliptical column shape close to a shape having semi-cylinders attached to both ends of a substantially rectangular parallelepiped having a length of 1.25 mm, a width of 1.2 mm, and a thickness of 0.9 mm. . The average mass of the particles was 1.8 mg / particle, the intrinsic viscosity (IV) was 0.383 dL / g, and R0 was 0.38.
The results are shown in Table 1. In Table 1, the added EG amount indicates the added ethylene glycol amount (parts by mass / h). “H” represents time (the same applies to Table 2 and the following). Further, W represents the amount (mass ppm) of tungsten atoms in the polyester, and Ti represents the amount (mass ppm) of titanium atoms in the polyester.

(Solid phase polycondensation)
Inert oven (manufactured by Yamato Scientific Co., Ltd.) in which 2.0 g of the above polyester prepolymer particles are arranged on an aluminum tray (vertical 160 mm × width 100 mm, depth: 30 mm) so that the chips do not overlap each other and the internal temperature is set to 60 ° C. , I / O DN4101). Under a nitrogen flow of 30 NL / min (where NL is a volume (L) at 0 ° C. and 1 atm), the temperature is raised from 60 ° C. to 160 ° C. in 30 minutes, and dried at 160 ° C. for 2 hours. Crystallization was performed. Thereafter, the temperature was raised to 230 ° C. over 30 minutes, and at 230 ° C., solid phase polycondensation for 8 hours and solid phase polycondensation for 16 hours were performed, respectively, to obtain a polyester. After the solid phase polycondensation was completed, the temperature was lowered to 60 ° C. over 30 minutes, and then the chip was recovered. The IV, R1, and ΔIV increase rates (ΔIV / h) of the sample with a solid phase polycondensation time of 8 hours and the sample with 16 hours were determined, respectively.
Table 2 shows the results of samples subjected to solid phase polycondensation for 8 hours after melt polycondensation and samples subjected to solid phase polycondensation for 16 hours.

<Comparative Example 1>
In Example 1, it carried out like Example 1 except having changed the temperature of the 2nd esterification reaction tank into 263 degreeC, and average residence time to 2.4 hours. The results are shown in Tables 1 and 2. The average mass of the particles was 1.8 mg / particle.

<Example 2>
In Example 1, it carried out similarly to Example 1 except having set the amount of ethylene glycol continuously added to a 2nd esterification reaction tank to 3.5 mass parts / hour. The results are shown in Tables 1 and 2. The average mass of the particles was 1.8 mg / particle, and the shape was almost uniform.

<Comparative example 2>
In Example 1, it carried out like Example 1 except the amount of ethylene glycol continuously added to a 2nd esterification reaction tank having been 2 mass parts / hour. The results are shown in Tables 1 and 2. The average mass of the particles was 1.8 mg / particle.

< Comparative Example 5 >
In Example 1, the amount and position of the catalyst were changed, and the second and third triple condensation reaction tanks were not used. Specifically, the procedure was as follows.

(Production of polyester prepolymer and prepolymerization of prepolymer)
In a slurry preparation tank, a slurry of terephthalic acid / isophthalic acid / ethylene glycol (molar ratio, 0.985: 0.015: 1.5) was prepared. In addition, 400 parts by mass of bis- (β-hydroxyethyl) terephthalate was charged into the first esterification tank, melted in a nitrogen atmosphere, and maintained at a temperature of 262 ° C. and a pressure of 92 kPaG. The slurry was continuously charged at 135 parts by mass / hour so that the average residence time as polyester was 4.8 hours, and the esterification reaction was carried out while distilling off the water produced from the separation tower. Was continuously transferred to the second esterification reactor. While continuously adding ethylene glycol to the second esterification reactor at 2.8 parts by mass / hour, the esterification reaction was carried out at an average residence time of 2.4 hours under a temperature of 260 ° C. and a pressure of 3.7 kPaG. The esterification rate of the reactant sample at the outlet of the second esterification reactor in the steady state was 92.6%.
Subsequently, the titanium catalyst prepared in Example 1 was applied to the esterification reaction product of the transfer pipe at the same time as the polyester prepolymer obtained by continuously transferring to the fully mixed first melt polycondensation reaction tank through the transfer pipe. In contrast, titanium, magnesium, and phosphorus were continuously added in amounts of 2 mass ppm, 1 mass ppm, and 1.6 mass ppm, respectively. Further downstream, the tungsten catalyst prepared in Example 1 was continuously added to the obtained polyester prepolymer so as to be 60 ppm by mass as tungsten.
In the first melt polycondensation reaction tank, the melt polycondensation reaction was carried out at an average residence time of 1.6 hours at a temperature of 270 ° C. and a pressure of 3 kPaA. The molten polyester prepolymer thus obtained was guided to the die head through a gear pump and an extraction pipe, and granulated by the same method as the prepolymer granulation method of Example 1. As a result, PET prepolymer particles having a substantially uniform shape and an elliptical columnar shape similar to a shape in which a semicylindrical body was attached to both ends of a substantially rectangular parallelepiped having a length of 1.25 mm, a width of 1.2 mm, and a thickness of 0.9 mm were obtained. The average mass of the particles was 1.8 mg / grain.

The obtained polyester prepolymer particles were subjected to solid phase polycondensation in the same manner as in Example 1. However, the solid phase polycondensation was 16 hours. The results are shown in Tables 1 and 3.

<Example 4>, <Comparative Example 3>
Comparative Example 5 was carried out in the same manner as Comparative Example 5 except that the pressure in the second esterification reaction tank and the average residence time in the first polycondensation tank were changed as shown in Table 1. The results are shown in Tables 1 and 3. In Example 4, the average mass of the particles was 1.8 mg / particle, which was a substantially uniform shape.

表２の比較例１、２と実施例１、２との比較より、また、表３の比較例５、実施例４と、比較例３との比較により、Ｒ０値等が本発明の範囲を満たす場合は満たさない場合より、ΔＩＶ／ｈが大きくなることが認められた。

From the comparison between Comparative Examples 1 and 2 and Tables 1 and 2 in Table 2, and by comparison between Comparative Example 5 and Example 4 and Comparative Example 3 in Table 3, the R0 value and the like are within the scope of the present invention. It was observed that ΔIV / h was greater when it was satisfied than when it was not.

表２の比較例１、２と実施例１、２との比較より、また、表３の実施例３、４と、比較例３との比較により、Ｒ０値等が本発明の範囲を満たす場合は満たさない場合より、ΔＩＶ／ｈが大きくなることが認められた。

When the R0 value and the like satisfy the scope of the present invention based on the comparison between Comparative Examples 1 and 2 and Tables 1 and 2 in Table 2 and the comparison between Examples 3 and 4 and Table 3 in Table 3. It was confirmed that ΔIV / h was larger than that in the case of not satisfying.

<Example 5>
(Crystallization process)
30 g of the prepolymer particles obtained in Example 4 are placed on a stainless steel bat having a bottom surface of 130 mm × 170 mm and a depth of 30 mm, and an inert oven having an internal gas temperature of 180 ° C. (manufactured by Tabay Espec, IPHH). -201M type), and a crystallization treatment was performed at 180 ° C. for 1 hour under a nitrogen flow rate of 50 NL / min and a temperature of 180 ° C. flowing through the inert oven.

(Heat treatment equipment)
The sample obtained by crystallizing the prepolymer particles obtained in Example 4 was heat-treated using the glass heat treatment apparatus shown in FIG.
Hereinafter, the heat treatment apparatus will be described.
In the heat treatment apparatus shown in FIG. 1, the sample is filled in a glass heat treatment tube (1) having an inner diameter of a sample filling portion of 45 mm. Nitrogen heated by oil filled in the oil bath (5) is introduced into the heat treatment pipe (1) via the gas flow meter (2), the nitrogen introduction pipe (3), and the nitrogen preheating pipe (4). Is done. The introduced nitrogen is dispersed by the dispersion plate (6) at the lower part of the heat treatment tube (1), becomes an upward flow having a substantially uniform linear velocity inside the heat treatment tube (1), and passes through the sample layer (7). To do. The nitrogen that has passed through the sample layer (7) is discharged from the gas purge port (9) to the outside of the heat treatment tube (1) through the filter (8) at the top of the heat treatment tube (1). The heat treatment tube (1) has a branch tube (10), and a sample can be input and a sample can be collected from an opening (normally closed by a glass stopper) in the upper portion thereof. The temperature of the sample inside the heat treatment tube (1) can be measured with a thermometer (12) equipped with a thermocouple (11). In the temperature range and superficial linear velocity in this example, the internal temperature of the heat treatment tube (1) is 2 ° C. lower than the oil temperature in the oil bath, so that the target solid-phase polycondensation temperature is reached. In contrast, the temperature of the oil was adjusted to a temperature 2 ° C. higher.

(First stage solid phase polycondensation process)
From the opening of the branch pipe (10) of the heat treatment pipe (1), 30 g of the prepolymer particles after the crystallization treatment were charged, and nitrogen was passed through to replace the inside with nitrogen. Thereafter, the superficial linear velocity of nitrogen in the heat treatment tube (1) (here, “superficial linear velocity” means the superficial linear velocity of the sample layer (hereinafter the same)) is 0.30 m / 210 at 210 ° C. The flow rate of nitrogen was set with a gas flow meter (2) so as to be seconds, and the heat treatment apparatus was immersed in the first oil bath (5) in which the oil temperature was adjusted to 212 ° C. This point is the start of the first stage solid phase polycondensation at 210 ° C. Two hours later, about 0.3 g of a sample for use was collected from the opening of the branch pipe (10).

(Temperature raising process)
After sampling, the flow rate of nitrogen is changed so that the superficial linear velocity of nitrogen is 1.0 m / sec at 235 ° C., and heat treatment is performed on the second oil bath (5) in which the oil temperature is adjusted to 237 ° C. The device was moved. This time was defined as the start of the temperature raising process at 235 ° C. It took 10 minutes for the temperature of the sample to reach 235 ° C. A sample was taken from the opening of the branch pipe (10) 10 minutes after the start of the heating step.
<Second stage solid phase polycondensation process>
After sampling, the flow rate of nitrogen was changed so that the superficial linear velocity of nitrogen was 0.30 m / sec at 230 ° C, and heat treatment was performed on the third oil bath (5) in which the oil temperature was adjusted to 232 ° C. The device was moved. This point was designated as the start of the second stage solid phase polycondensation at 230 ° C. A sample was taken at 8 hours from the start of the second stage solid phase polycondensation. Intrinsic viscosities (IV), R1, and ΔIV / h of samples collected at 8 hours after the second stage solid phase polycondensation were determined. The results are shown in Table 4.

<Comparative example 4>
The same procedure as in Example 5 was performed except that the prepolymer particles obtained in Comparative Example 3 were used instead of the prepolymer particles obtained in Example 4. The results are shown in Table 4. In this example, since R0 was larger than 0.60, ΔIV / h was smaller than that in Example 5.

<Example 6>
(Manufacture of polyester)
The method for producing polyester is shown below.

(Manufacture of raw material oligomers)
After supplying 2012 kg (10.4 × 10 ³ mol) of dimethyl terephthalate and ethylene glycol 1286 (20.7 × 10 ³ mol) to the esterification reactor and dissolving them, calcium acetate dissolved in ethylene glycol was converted into calcium. It added so that it might become 0.20 kg (100 ppm with respect to the product obtained by transesterification) as an atom, and transesterification was performed, distilling the produced | generated methanol, hold | maintaining at 220 degreeC. After the transesterification reaction was completed, 1721 kg (10.4 × 10 ³ mol) of terephthalic acid and 772 kg (12.4 × 10 ³ mol) of ethylene glycol were stirred and mixed in this esterification reaction vessel in the slurry preparation vessel. The obtained slurry was continuously transferred over 3 hours, subjected to esterification reaction at 250 ° C. under normal pressure, and after 4 hours of reaction from the start of transfer, 50% of the reaction solution was extracted out of the system. .
In this esterification reaction tank, an esterification reaction was performed by adding a slurry composed of terephthalic acid and ethylene glycol obtained in the same manner as described above, and the step of extracting 50% of the reaction solution was repeated a total of 10 times, The concentration of calcium acetate during the esterification reaction was set to 0.5 mass ppm or less.
In this manner, an esterification reaction product composed of terephthalic acid and ethylene glycol substantially containing no transesterification catalyst component was produced. The esterification reaction product was extracted from the esterification reaction tank, and cooled and solidified in the air to obtain a raw material oligomer used in the following examples. The esterification reaction rate of the obtained raw material oligomer was 89%.

(Production of polyester prepolymer)
104 g of the raw material oligomer was transferred to a polycondensation reactor equipped with a stirrer with a torque meter, and the system was purged with nitrogen. Then, the oligomer was dissolved in an oil bath (fixed at 260 ° C.) under normal pressure. Hereinafter, the time is expressed by setting the oligomer dissolution start time as 0 hours.
After 30 minutes, stirring was started at 50 rpm, and after 60 minutes, it was confirmed that the oligomer was completely dissolved, and then a tungsten catalyst (ammonium metatungstate aqueous solution (trade name: MW-2, manufactured by Nippon Inorganic Chemical Industries, Ltd., 3 Tungsten oxide (WO ₃ ) in a concentration of 50% by mass)) was diluted with ethylene glycol so as to be 40 mass ppm as tungsten with respect to the obtained polyester prepolymer, and 2 ml was added. Depressurization was started after 65 minutes, and the pressure was reduced to 0.27 kPaA after 125 minutes. The depressurization operation was performed so that the logarithmic value of the pressure was inversely proportional to the time. The polycondensation temperature was increased from 260 ° C. to 280 ° C. at a constant rate between 65 minutes and 145 minutes. The polycondensation time and melt polycondensation reaction shown in Table 5 were performed so that the intrinsic viscosity reached was in the range of 0.40 to 0.50 dL / g. The polycondensation time was defined as the time from the start of decompression to the return to normal pressure.
After completion of the polycondensation, stirring was stopped, the pressure was returned to normal pressure with nitrogen, and the polycondensation reactor was taken out from the oil bath. After removing the polycondensation reactor from the oil bath, quickly open the outlet of the reactor, pull out the polyester by slightly pressurizing the system with nitrogen, water-cool and solidify to obtain a strand-like polyester It was. The obtained polyester was cut so that the average mass of the particles was 1 mg / particle. The obtained polyester had an intrinsic viscosity of 0.401 dL / g and R0 of 0.33.

(Solid phase polycondensation)
Inert oven (manufactured by Yamato Scientific Co., Ltd.) in which 2.0 g of the above polyester prepolymer particles are arranged on an aluminum tray (vertical 160 mm × width 100 mm, depth: 30 mm) so that the chips do not overlap each other and the internal temperature is set to 60 ° C. , I / O DN4101). Under a nitrogen flow of 30 NL / min (where NL is a volume (L) at 0 ° C. and 1 atm), the temperature is raised from 60 ° C. to 160 ° C. in 30 minutes, and dried at 160 ° C. for 2 hours. Crystallization was performed. Then, it heated up to 230 degreeC over 30 minutes, solid phase polycondensation was performed at 230 degreeC for 8 hours, and polyester was obtained. After the solid phase polycondensation was completed, the temperature was lowered to 60 ° C. over 30 minutes, and then the chip was recovered. IV, R1, and ΔIV / h of a sample having a solid phase polycondensation time of 8 hours were determined. The results are shown in Table 5.

<Example 7>
The catalyst type and addition operation in the melt polycondensation were changed from those in Example 6, and the specific procedure was as follows.

(Melt polycondensation)
104 g of the raw material oligomer produced in the same manner as in Example 6 was transferred to a polycondensation reactor equipped with a stirrer with a torque meter, and the system was replaced with nitrogen. Then, the oligomer was dissolved in an oil bath under normal pressure (constant 260 ° C.). went. Hereinafter, the time is expressed by setting the oligomer dissolution start time as 0 hours.
Stirring was started at 50 rpm after 30 minutes, and after confirming that the oligomer was completely dissolved after 60 minutes, a titanium catalyst (tetra-n-butyl titanate (TBT)) was added to the obtained polyester prepolymer with titanium. As a result, it was diluted with ethylene glycol so as to be 4 ppm by mass, and 1 mL was added. Then, after 65 minutes, a tungsten catalyst (ammonium metatungstate aqueous solution (trade name: MW-2, manufactured by Nippon Inorganic Chemical Industry Co., Ltd., concentration of 50% by mass as tungsten trioxide (WO ₃ )) is used with respect to the obtained polyester prepolymer. Then, it was diluted with ethylene glycol so as to be 40 ppm by mass as tungsten, and 1 mL was added. After 70 minutes, pressure reduction was started, and after 130 minutes, the pressure was reduced to 0.27 kPaA. The depressurization operation was performed so that the logarithmic value of the pressure was inversely proportional to the time. The polycondensation temperature was raised from 260 ° C. to 280 ° C. at a constant rate between 70 minutes and 150 minutes. The polycondensation time and melt polycondensation reaction shown in Table 5 were performed so that the intrinsic viscosity reached was in the range of 0.40 to 0.50 dL / g. The polycondensation time was defined as the time from the start of decompression to the return to normal pressure.
After completion of the polycondensation, stirring was stopped, the pressure was returned to normal pressure with nitrogen, and the polycondensation reactor was taken out from the oil bath. After removing the polycondensation reactor from the oil bath, quickly open the outlet of the reactor, pull out the polyester by slightly pressurizing the system with nitrogen, water-cool and solidify to obtain a strand-like polyester It was. The obtained polyester was cut so that the average mass of the particles was 1 mg / particle. The intrinsic viscosity of the obtained polyester was 0.446 dL / g, and R0 was 0.42.
The obtained polyester prepolymer particles were subjected to solid phase polycondensation in the same manner as in Example 6. The results are shown in Table 5.

<Example 8>
In Example 6, the tungsten catalyst was replaced with a titanium catalyst (tetra-n-butyl titanate (TBT)), and the resulting polyester prepolymer was diluted with ethylene glycol so as to be 4 mass ppm as titanium, and 2 mL was added. Otherwise, melt polycondensation was performed in the same manner to obtain a polyester. The obtained polyester had an intrinsic viscosity of 0.439 dL / g and R0 of 0.30. The obtained polyester prepolymer particles were subjected to solid phase polycondensation in the same manner as in Example 6. The results are shown in Table 5.

<Example 9>
(Preparation of catalyst)
The catalyst type and addition operation in the melt polycondensation were changed from those in Example 6, and the specific procedure was as follows.
(Melt polycondensation)
104 g of the raw material oligomer produced in the same manner as in Example 6 was transferred to a polycondensation reactor equipped with a stirrer with a torque meter, and the system was replaced with nitrogen. Then, the oligomer was dissolved in an oil bath under normal pressure (constant 260 ° C.). went. Hereinafter, the time is expressed by setting the oligomer dissolution start time as 0 hours.
After 30 minutes, stirring was started at 50 rpm, and after 60 minutes, it was confirmed that the oligomer was completely dissolved. Then, ethyl acid phosphate (trade name: JP-502, manufactured by Johoku Chemical Co., Ltd., monoester and diester) A weight ratio of 0.82: 1, abbreviation: EAP) was diluted with ethylene glycol so as to be 13 mass ppm as phosphorus with respect to the obtained polyester prepolymer, and 0.7 mL was added. Then, after 65 minutes, 1.3 mL of an antimony catalyst (antimony trioxide (abbreviation: SbO) 1.8% by mass ethylene glycol solution) was added as antimony to 220 ppm by mass with respect to the obtained polyester prepolymer. After 70 minutes, pressure reduction was started, and after 130 minutes, the pressure was reduced to 0.27 kPaA. The depressurization operation was performed so that the logarithmic value of the pressure was inversely proportional to the time. The polycondensation temperature was raised from 260 ° C. to 280 ° C. at a constant rate between 70 minutes and 150 minutes. The polycondensation time and melt polycondensation reaction shown in Table 5 were performed so that the intrinsic viscosity reached was in the range of 0.40 to 0.50 dL / g. The polycondensation time was defined as the time from the start of decompression to the return to normal pressure.
After completion of the polycondensation, stirring was stopped, the pressure was returned to normal pressure with nitrogen, and the polycondensation reactor was taken out from the oil bath. After removing the polycondensation reactor from the oil bath, quickly open the outlet of the reactor, pull out the polyester by slightly pressurizing the system with nitrogen, water-cool and solidify to obtain a strand-like polyester It was. The obtained polyester was cut so that the average mass of the particles was 1 mg / particle. The intrinsic viscosity of the obtained polyester was 0.447 dL / g, and R0 was 0.34. The content of antimony atoms in the polyester was 215 mass ppm.
The obtained polyester prepolymer particles were subjected to solid phase polycondensation in the same manner as in Example 6. The results are shown in Table 5.

  From the results of Examples 6 to 9 in Table 5, it can be seen that the best catalytic activity is obtained when a tungsten catalyst and a titanium catalyst are used in combination, and a high molecular weight polyester can be produced in a shorter time.

  According to the present invention, a polyester having a high molecular weight, a uniform shape and a low content of antimony atoms can be produced in a short polycondensation time. Furthermore, since the intrinsic viscosity of the polyester prepolymer is low, it is not necessary to use a complicated and expensive melt polycondensation reaction apparatus, and an efficient production method can be provided.

It is a schematic diagram which shows one structural example of the glass heat processing apparatus used by this invention.

Explanation of symbols

1: Heat treatment tube 2: Gas flow meter 3: Nitrogen introduction tube 4: Nitrogen preheating tube 5: Oil bath 6: Dispersion plate 7: Sample layer 8: Filter 9: Gas purge port 10: Branch pipe 11: Thermocouple 12: Thermometer

Claims (10)

An esterification step (a) in which an oligomer is obtained by an esterification reaction using an esterification catalyst using a dicarboxylic acid component having an aromatic dicarboxylic acid as a main component and a diol component having an aliphatic diol as a main component as raw materials. A melt polycondensation step (b) for obtaining a prepolymer by a melt polycondensation reaction of the obtained oligomer, a granulation step (c) using the obtained prepolymer as a prepolymer particle, and the resulting prepolymer particle in a solid phase polymerization A continuous polyester production method comprising a solid phase polycondensation step (d) for obtaining a polyester by a condensation reaction, wherein the following (1) to (4) are satisfied: .
(1) The esterification rate of the esterification reaction product obtained in the esterification step (a) is 86% to 96%.
(2) Add at least one esterification catalyst to the melt polycondensation step (b) and / or the previous step.
(3) The ratio R0 of the number of terminal carboxyl groups to the total number of terminal groups of the prepolymer particles obtained in the granulating step (c) is 0.25 to 0.60, and the intrinsic viscosity is 0.25 dL / g to 0.00. 50 dL / g.
(4) The ratio R1 of the number of terminal carboxyl groups to the total number of terminal groups of the polyester obtained in the solid phase polycondensation step (d) and R0 satisfy the following (Formula 1), and the intrinsic viscosity is 0.7 dL / g to 1.5 dL / g.
(Formula 1) R0-R1 ≦ 0.1   2. The method for producing a polyester according to claim 1, wherein a tungsten catalyst is used as the esterification catalyst.   The method for producing a polyester according to claim 1 or 2, wherein a titanium catalyst is used as the esterification catalyst. R0 and R1 satisfy | fill the following (Formula 2), The manufacturing method of the polyester of any one of Claims 1-3 characterized by the above-mentioned.
(Formula 2) −0.2 ≦ R0−R1   The method for producing a polyester according to any one of claims 1 to 4, wherein a tungsten catalyst and a titanium catalyst are added in this order as an esterification catalyst. A raw material preparation step prior to the esterification step (a), and an oligomer transfer step between the esterification step (a) and the melt polycondensation step (b), and the tungsten catalyst is converted into the esterification step (a) and / or The method for producing a polyester according to claim 5, wherein the polyester catalyst is added in the raw material preparation step, and further a titanium catalyst is added to the melt polycondensation step (b) and / or the previous step.   The method for producing a polyester according to any one of claims 1 to 4, wherein a titanium catalyst and a tungsten catalyst are added in this order as the esterification catalyst. Having a raw material preparation step prior to the esterification step (a), adding a titanium catalyst to the esterification step (a) and / or the raw material preparation step, and further adding a tungsten catalyst to the melt polycondensation step (b) and / or earlier The method for producing a polyester according to claim 7, wherein the polyester is added to the step.   9. The method for producing a polyester according to claim 1, wherein the prepolymer particles have an average mass of 1.0 mg / grain to 50 mg / grain.   The method for producing a polyester according to any one of claims 1 to 9, wherein the content of antimony atoms in the polyester is 10 mass ppm or less.

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