JP2006241294A - Polyester resin and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin and a method for producing the same in which the by-production of a cyclic trimer and the like is suppressed and the intrinsic viscosity is maintained at a high level during the melt molding. <P>SOLUTION: The method for producing a polyester resin comprises producing a polyester resin (A) from a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of ethylene glycol using a titanium compound as a catalyst and bringing the polyester resin (A) into contact with a phosphorus compound to obtain a polyester resin (B), wherein the polyester resin (B) satisfies the following formulas: (1) 0.002≤T≤0.2, (2) P/(T+X)≥4.0, and (3) X≥0 (wherein T denotes the content (mol/ton of resin (B)) of titanium atoms; X denotes the content (mol/ton of resin (B)) of metal atoms other than titanium atoms; and P denotes the content (mol/ton of resin (B)) of phosphorus atoms. There is also provided the polyester resin (B)). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

Polyester resins, especially polyethylene terephthalate resins, are excellent in mechanical strength, chemical stability, gas barrier properties, hygiene and the like, and are used in various applications such as films and bottles. In particular, the demand for hollow molded containers such as bottles for various beverages has grown significantly in recent years.
A hollow molded body such as a bottle is usually produced by, for example, injection-molding a preform from, for example, polyethylene terephthalate resin, softening the preform by reheating, and then performing stretch blow molding.

  In bottles that require heat sterilization and filling, when the blow blow molding is performed, the blow mold is heated to heat-set the bottle, and the oriented crystals of the molecular chains by stretching are fixed to improve the heat resistance. It is expressed. However, the cyclic trimer (cyclotriethylene terephthalate), etc. produced as a by-product in the resin during melt molding such as injection molding to form a preform moves to the mold surface during stretch blow molding and heat setting. The mold surface is transferred to the bottle surface where the mold contamination is obtained, and the surface smoothness of the bottle is impaired, the transparency is inferior, and the productivity is greatly deteriorated due to the mold cleaning. was there.

  Therefore, in order to improve such mold contamination, a method of bringing the resin into contact with a phosphorus compound has been proposed. For example, Patent Document 1 discloses a method for treating polyethylene terephthalate, which comprises contacting solid phase polycondensed polyethylene terephthalate resin pellets with an aqueous phosphoric acid solution having a concentration of 1 ppm or more. However, this method does not necessarily have a sufficient effect of suppressing by-products such as cyclic trimers, and a relatively high processing temperature is required to obtain a sufficient effect. In addition, there is a drawback that the lowering of the intrinsic viscosity is promoted at the time of melt molding.

  In Patent Document 2, phosphorous acid, hypophosphorous acid, or an esterified product thereof having a concentration in terms of phosphorus atom of 10 ppm or more, or an aqueous solution or organic solvent solution of phosphoric acid ester and a polyethylene terephthalate resin are brought into contact with each other. A method has been proposed. However, as a result of studies by the present inventors, in this patent method, a decrease in intrinsic viscosity during melt molding was suppressed, but the effect of suppressing by-products such as cyclic trimers during melt molding was insufficient. Patent Document 3 discloses a method of bringing a polyester resin into contact with a phosphorus compound solution having a pH of 5 or less at 50 ° C. to 200 ° C. In this method, the inherent viscosity of the polyester resin is lowered before and after the contact treatment. It is large and is not suitable as a method for producing a resin for bottles.

  Patent Document 4 discloses a specific amount of a phosphorus compound having a hydroxyl group derived from phosphoric acid in polyethylene terephthalate containing a specific amount of one or more metal atoms selected from antimony, titanium, and nickel atoms, or a polyester mainly composed thereof. It is disclosed that, by blending, a polyester having a small amount of cyclic oligomer formation upon melting is obtained. As a specific method, a polyester is produced by melt polycondensation and solid phase polymerization, and then a phosphorus compound is contained. It is disclosed that a thermoplastic resin and polyester are kneaded.

However, according to this method, a manufacturing process of a thermoplastic resin containing a phosphorus compound and a kneading process of the resin and polyester are necessary, and therefore it is inevitable to increase the man-hours and manufacturing costs for obtaining a final molded product. It was not realistic for industrial use. In addition, if the thermoplastic resin containing the phosphorus compound and polyester are not sufficiently kneaded, the amount of oligomer formation cannot be suppressed, and it is necessary to take sufficient melt residence time during melt molding, and productivity A decrease is inevitable, and in particular, in the case of injection molding or injection blow molding with a generally short melt residence time, a sufficient oligomer suppressing effect cannot be obtained.
JP-A-5-97990 JP 2001-81176 A JP 2002-322261 A JP-A-10-251393

  An object of the present invention is to provide a method for producing a polyester resin in which by-products such as a cyclic trimer at the time of melt molding are sufficiently suppressed and a high retention rate of intrinsic viscosity at the time of melt molding, and a polyester resin produced by the method Is to provide.

The present invention achieves the above-mentioned problems, the gist of which is produced from a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component using a titanium compound as a catalyst. The polyester resin (A) is brought into contact with a phosphorus compound, and the polyester resin (B) obtained after the contact satisfies the following formulas (1) to (3), and the polyester resin: It exists in (B).
(1) 0.002 ≦ T ≦ 0.2
(2) P / (T + X) ≧ 4.0
(3) X ≧ 0
In the formulas (1) to (3), T is the content of titanium atoms per ton of the polyester resin (B) (mol / ton of resin), and X is other than the titanium atoms per ton of the polyester resin (B). The content of metal atoms (mol / ton of resin) and P represent the content of phosphorus atoms per ton of polyester resin (B) (mol / ton of resin).

  The polyester resin obtained by contacting with the phosphorus compound by the production method of the present invention contains a specific atom in a specific amount ratio, and the resin after the contact is injection molded, stretch blown, or heat set. When molding into bottles, etc., the contamination of the mold is greatly prevented compared to the conventional one, and the resulting bottle can have excellent surface smoothness and transparency, and the time for mold cleaning The productivity of bottles and the like can be greatly improved. Further, since the resin after contact has a good retention rate of the intrinsic viscosity, the obtained bottle has a high intrinsic viscosity and excellent strength and the like.

The description of the constituent features of the present invention described below is a representative example of the embodiment, and is not limited to the contents thereof.
The polyester resin production method of the present invention comprises a polyester resin (A) produced using a titanium compound as a catalyst from a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component. The polyester resin (B) obtained after contacting with a phosphorus compound and satisfying the following formulas (1) to (3) is a method for producing a polyester resin.

(1) 0.002 ≦ T ≦ 0.2
(2) P / (T + X) ≧ 4.0
(3) X ≧ 0
In the formulas (1) to (3), T is the content of titanium atoms per ton of the polyester resin (B) (mol / ton of resin), and X is other than the titanium atoms per ton of the polyester resin (B). The content of metal atoms (mol / ton of resin) and P represent the content of phosphorus atoms per ton of polyester resin (B) (mol / ton of resin).
Here, the content of each atom per ton of the polyester resin includes not only those present in the resin but also those adhered to the resin surface.
And the polyester resin (B) obtained by the method of the present invention suppresses by-production of the cyclic trimer during the melt molding, and achieves a good retention rate of the intrinsic viscosity.

The polyester resin (A) in the present invention is produced from a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component using a titanium compound as a catalyst.
The dicarboxylic acid component used in the present invention contains terephthalic acid as a main component. Here, the main component means that terephthalic acid is 50 mol% or more with respect to the total dicarboxylic acid component. Mole% or more is preferable, and 95% or more is more preferable.

  Examples of dicarboxylic acid components other than terephthalic acid include phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalic acid, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, and 4,4′-diphenyletherdicarboxylic acid. 4,4′-diphenylketone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid and other aromatic dicarboxylic acids, hexahydroterephthalic acid , Alicyclic dicarboxylic acids such as hexahydroisophthalic acid, and aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid , Etc. Of these, isophthalic acid is preferred in the present invention.

The diol component used in the present invention is a diol component mainly composed of ethylene glycol. Here, the main component means that ethylene glycol is 50 mol% or more of all diol components, preferably 80 mol% or more, and more preferably 95 mol% or more.
Examples of the diol component other than ethylene glycol include diethylene glycol, for example, 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, polyethylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedi Cycloaliphatic diols such as methylol, 2,5-norbornane dimethylol, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyl) Nyl) propane, 2,2-bis (4′-hydroxyethoxyphenyl) propane, aromatic diols such as bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyethoxyphenyl) sulfonic acid, and 2,2-bis An ethylene oxide adduct or propylene oxide adduct of (4′-hydroxyphenyl) propane may be mentioned.

  In the production of the polyester resin (A) in the present invention, if necessary, as a copolymerization component, for example, hydroxycarboxylic acid such as glycolic acid, p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid, alkoxycarboxylic acid, And monofunctional components such as stearyl alcohol, heneicosanol, octacosanol, benzyl alcohol, stearic acid, behenic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, Trifunctional or more polyfunctional components such as naphthalenetetracarboxylic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, sugar ester, and the like may be used.

Moreover, as polyester resin (A) in this invention, it is preferable that content of the ethylene glycol unit is 97.0 mol% or more with respect to all the diol components. Examples of diol units other than ethylene glycol include diethylene glycol by-produced in the reaction system and diethylene glycol units based on diethylene glycol added from outside the system as a copolymerization component. It is preferably less than 3.0 mol%, more preferably 2.5 mol% or less, particularly preferably 2.0 mol% or less, based on the diol component. If the content of diethylene glycol units exceeds the above range, the polyester resin (A) is treated with a phosphorus compound, and the polyester resin (B) after heat treatment as a molded article such as a bottle of a polyester resin (B), gas barrier properties, There is a tendency that problems such as deterioration of stress cracking property and deterioration of thermal stability are likely to occur.
Moreover, it is preferable that content of a terephthalic acid unit is 99.0 mol% or more with respect to all the dicarboxylic acid components. When the content of the terephthalic acid unit is less than the above range, the heat resistance of the polyester resin (B) as a molded body such as a heat-resistant bottle tends to be inferior.

In the production of the polyester resin (A) in the present invention, a titanium compound is used as a catalyst, and the titanium compound can be appropriately selected from conventionally known titanium compounds.
Specific examples of the titanium compound include tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate, and titanium acetate. , Titanium oxalate, potassium titanium oxalate, sodium oxalate, potassium titanate, sodium titanate, titanium chloride, titanium chloride-aluminum chloride mixture, among others, tetra-n-propyl titanate, tetra-i-propyl titanate, Titanium alkoxides such as tetra-n-butyl titanate, titanium oxalate, and potassium potassium oxalate are preferred.

  The amount of the titanium compound used is preferably 0.002 ≦ TA ≦ 0.200, where TA (mol / ton of resin) is the content of titanium atoms present in the resulting polyester resin (A). More preferably, 0.020 ≦ TA ≦ 0.200, still more preferably 0.060 ≦ TA ≦ 0.100, and particularly preferably 0.070 ≦ TA ≦ 0.090. When TA exceeds this range, the value of titanium atom content T of the polyester resin (B) obtained by bringing the polyester resin (A) into contact with the phosphorus compound also increases, and P / (T + X) tends to decrease. Therefore, the by-product amount of the cyclic trimer at the time of melt molding tends to increase, the retention rate of the intrinsic viscosity tends to decrease, and the color tone of the polyester resin (B) is yellowish Become. On the other hand, when TA is smaller than this range, the polycondensation rate and the reduction rate of the cyclic trimer in obtaining the polyester resin (A) are reduced, and the cyclic trimer content of the polyester resins (A) and (B) is contained. The amount tends to increase, the productivity of the resin and the amount of the cyclic trimer of the molded body obtained by melt molding increase, and the mold contamination tends to increase.

  Here, the ratio of P to the total sum of T and X represented by P / (T + X), that is, the amount of phosphorus atoms relative to the amount of titanium and other metal atoms present in the polyester resin (B). The ratio is an index indicating the deactivation effect of the catalytic ability of titanium and other metals by phosphorus. When this value is large, the by-production of cyclic trimer during molding and the decrease in intrinsic viscosity are suppressed. It shows a tendency to decrease raw and intrinsic viscosity.

In the present invention, a polyester resin (A) is obtained by using a titanium compound catalyst that sufficiently achieves the polycondensation reaction rate and the reduction rate of the cyclic trimer in such a relatively small amount, and this resin (A) and The P / (T + X) value of the polyester resin (B) obtained after contact with the phosphorus compound can be increased, and the deactivation of titanium and other metals by phosphorus can be increased. As a result, the resin (B) can be melted. It is possible to suppress a reduction in the amount of by-product and intrinsic viscosity of the cyclic trimer during molding.
In addition, as a titanium compound used as a catalyst, since a solid titanium compound insoluble in an organic solvent or water generally has a low catalytic activity and a large amount necessary for a polycondensation reaction, the obtained polyester resin (A) is a phosphorus compound. P / (T + X) of the polyester resin (B) obtained by contact with the resin tends to be small, and the by-product amount of the cyclic trimer during melt molding tends to increase, or the intrinsic viscosity tends to decrease. It is not preferable.

  Moreover, you may use together the compound of metal atoms other than titanium as a catalyst, a promoter, an esterification catalyst, etc. at the time of manufacture of a polyester resin (A). Here, the metal atom other than titanium includes all the metal atoms of Group 1 to Group 15 of the periodic table other than titanium atom, for example, antimony, germanium, aluminum, zinc, tin, copper, lead, cobalt, iron, Examples include manganese, tungsten, zirconium, hafnium, beryllium, magnesium, calcium, strontium, barium, lithium, sodium, potassium, rubidium, and cesium. In the production method of the present invention, the amount of the metal atom compound other than titanium varies depending on the kind of the compound, but it is preferably a very small amount of the metal atom other than titanium present in the polyester resin (A). Assuming that the content of the compound is XA (mol / ton of resin), the preferred XA value has an upper limit of 1.3, more preferably 0.400, and further preferably 0.300. 0.220 is particularly preferable.

The lower limit of XA varies depending on the catalyst performance of the titanium compound and the type of the metal compound used in combination, but is preferably 0, more preferably 0.004, still more preferably 0.060, Particularly preferred is .070.
When XA is large, the X value of the polyester resin (B) obtained by bringing the polyester resin (A) into contact with the phosphorus compound tends to increase, and the P / (T + X) value tends to decrease, and the resin (B) melts. The by-product amount of the cyclic trimer at the time of molding tends to increase, or the inherent viscosity retention rate tends to decrease. On the other hand, when XA is small, the effect of the metal compound to be used together cannot be achieved, and the polycondensation reaction rate and the reduction rate of the cyclic trimer in obtaining the polyester resin (A) are lowered, and the polyester resins (A) and (B ) May increase, the resin productivity may deteriorate, the amount of the cyclic trimer of the molded product obtained by melt molding may increase, and mold contamination may increase. .

Moreover, you may use a phosphorus compound together as an adjuvant, a stabilizer, etc. at the time of manufacture of a polyester resin (A).
As the amount of the phosphorus compound to be used, when the content of phosphorus atoms present in the polyester resin (A) is PA (mol / ton of resin), the above formula (6) is 0.020 ≦ PA ≦ 0.300. Preferably, 0.050 ≦ PA ≦ 0.200, more preferably 0.080 ≦ PA ≦ 0.180, and more preferably 0.090 ≦ PA ≦ 0.150. Particularly preferred. If PA exceeds this range and is too small, P / (T + X) of the polyester resin (B) obtained by bringing the polyester resin (A) into contact with the phosphorus compound tends to be small, and the resin (B) is melt-molded. There is a tendency that the amount of by-product of the cyclic trimer increases or the retention of intrinsic viscosity decreases. On the other hand, if PA exceeds this range, the polycondensation rate in the polycondensation reaction and the reduction rate of the cyclic trimer are reduced, and the cyclic trimer content of the polyester resins (A) and (B) is increased. In some cases, the productivity of the resin and the amount of the cyclic trimer of the molded product obtained by melt molding increase, and the mold contamination may increase.

  The method for producing a polyester resin of the present invention includes a step of bringing the polyester resin (A) produced using a relatively small amount of a titanium compound catalyst into contact with a phosphorus compound as described above. The phosphorus compound is impregnated and adhered in (A) or on the surface thereof, and P / (T + X) of the resulting polyester resin (B) is within a predetermined range. As a result, when the polyester resin (B) is melt-molded, a large amount of phosphorus compound reacts with a small amount of a titanium compound and a metal compound other than titanium to deactivate these catalysts, thereby producing a by-product of a cyclic trimer. It is thought that it suppresses or a decrease in intrinsic viscosity.

  In the method for producing a polyester resin of the present invention, it is essential that P / (T + X) of the polyester resin (B) is within a predetermined value range. For this reason, the contact condition between the polyester resin (A) and the phosphorus compound Is adjusted so that the content of each atom in the obtained polyester resin (B) satisfies the predetermined range, for example.

  Examples of the phosphorus compound to be brought into contact with the polyester resin (A) include orthophosphoric acid, polyphosphoric acid, trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris ( Triethylene glycol) phosphate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, phosphate ester such as triethylphosphonoacetate, etc. 5 Divalent phosphorus compounds, and phosphorous acid, hypophosphorous acid, and trimethyl phosphite, diethyl phosphite, Trivalent phosphorus compounds such as phosphites such as reethyl phosphite, trisdodecyl phosphite, trisnonyl decyl phosphite, ethyl diethyl phosphonoacetate, triphenyl phosphite, metal salts such as lithium, sodium and potassium, Examples thereof include hypophosphorous acid esters. Among these, the polyester resin (A) or the surface thereof is impregnated and adhered with a phosphorus compound efficiently by a contact treatment at a low temperature for a short time, and the value of P / (T + X) of the resulting polyester resin (B) is In order to obtain a relatively large value within the predetermined range, acidic phosphates such as methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, and butyl acid phosphate are preferable, and ethyl acid phosphate is particularly preferable.

  When using a phosphorus compound other than the acidic phosphate ester, although depending on the type of the compound, impregnation and adhesion of the phosphorus compound to the polyester resin (A) hardly occur, and P / (T + X) of the obtained polyester resin (B) ) In the predetermined range is somewhat difficult, or in order to make the value in the predetermined range, it tends to require a relatively high temperature and a long time for contact with the polyester resin (A). For example, when a phosphate ester such as triethyl phosphate is used, impregnation and adhesion of the phosphorus compound to the polyester resin (A) hardly occur, and the value of P / (T + X) of the obtained polyester resin (B) is compared within a predetermined range. It may be difficult to set a large value. In addition, in order to make P / (T + X) of the polyester resin (B) obtained by using regular phosphoric acid within a predetermined range, it tends to require high temperature and long time contact with the polyester resin (A). In some cases, the decrease in intrinsic viscosity during melt molding tends to increase.

  In the production method of the present invention, when the polyester resin (A) is contacted with the phosphorus compound, the phosphorus compound may be directly contacted with the polyester resin (A), or the phosphorus compound is dissolved and dispersed in a medium such as a solution. The polyester resin (A) may be brought into contact with the polyester resin (A), but the phosphorus compound is used as a solution, so that the phosphorus compound can be efficiently impregnated and adhered to the polyester resin (A) with a small amount of the phosphorus compound. It is preferable from the viewpoint. As a solvent used for the solution of the phosphorus compound, water and / or alcohols compatible with water are preferable, water, ethanol and isopropanol are more preferable, and water and isopropanol are particularly preferable.

  When the polyester resin (A) is brought into contact with the phosphorus compound solution, the concentration of the phosphorus compound in the solution is preferably 10 ppm by weight or more as a phosphorus atom, and preferably 10 to 100,000 ppm by weight. More preferably, it is 1000-50000 weight ppm. When the concentration of phosphorus atoms in the phosphorus compound solution is less than the above range, a relatively high temperature and a long contact time are required for the value of P / (T + X) in the obtained polyester resin (B) to be within the predetermined range. On the other hand, when the concentration range is exceeded, corrosion or the like of the contact treatment facility between the polyester resin (A) and the phosphorus compound tends to occur.

  In the production method of the present invention, the contact method between the phosphorus compound and the polyester resin (A) can be performed either continuously or batchwise. In the case of carrying out continuously, for example, a tower-type contact treatment apparatus is used, and the pellet-shaped polyester resin (A) is continuously supplied from the upper part of the tower-type contact treatment apparatus, and at the same time, a phosphorus compound solution is added to the tower. The polyester resin (A) is immersed in and brought into contact with the phosphorus compound solution, and continuously discharged from the resin and the phosphorus compound solution. The method for supplying the phosphorus compound at this time may be either parallel flow or counter flow with respect to the polyester resin (A). When performing by a batch type, for example, using a silo type contact treatment device, the polyester resin (A) and the phosphorus compound solution are put, and the polyester resin (A) is immersed in the phosphorus compound solution and brought into contact.

  After contacting the phosphorus compound solution and the polyester resin (A), the phosphorus compound solution and the polyester resin (A) are usually separated, drained with a draining device such as a granular vibrating screen or a Simon Carter, and dried. To do. Before drying, a commonly used polyester resin washing method can be used, and it can be washed with water and / or alcohols. When a phosphorus compound is used as a solution, the solvent is the same type as the solvent of the solution. However, it is usually finally washed with water. Moreover, the drying method of the polyester resin used normally can be used for the drying method.

The contact temperature and contact time between the polyester resin (A) and the phosphorus compound solution are such that the content of each atom of the resulting polyester resin (B) satisfies the predetermined range of the formula P / (T + X). Adjusted.
The contact temperature is usually 0 to 100 ° C., and the contact time is usually 5 minutes to 10 hours. The higher the contact temperature, the greater the amount of phosphorus atoms impregnated / attached to the polyester resin (A), and the contact time can be shortened, but the contact treatment equipment between the polyester resin (A) and the phosphorus compound It tends to be easy to cause corrosion. In addition, the longer the contact time, the more the amount of impregnation and adhesion of the phosphorus atom to the polyester resin (A) tends to increase. However, the contact processing facility becomes enormous or the productivity decreases.

  In the production method of the present invention, the contact temperature and time are determined in consideration of the balance between the two, but the contact temperature is preferably 0 to 70 ° C, more preferably 40 to 70 ° C. When the contact temperature is 0 to 40 ° C., the contact time is preferably 2 to 10 hours, more preferably 6 to 10 hours, and when the contact temperature is 40 to 70 ° C., preferably 2 to 6 hours, the contact temperature 70 In the case of -100 degreeC, Preferably it is 0.1 to 2 hours. Among these, from the viewpoint of the corrosion problem of the contact treatment equipment and the balance between the equipment scale and productivity, the contact temperature is most preferably 40 to 70 ° C. and the contact time is 2 to 6 hours.

  In the production method of the present invention, the polyester resin (A) to be brought into contact with the phosphorus compound is produced using a relatively small amount of a titanium compound catalyst, and the type of phosphorus compound used for the contact treatment, the concentration of the phosphorus compound solution, etc. By appropriately adjusting, it is possible to achieve sufficient impregnation and adhesion of phosphorus atoms to the resin (A) at the same processing time at a lower temperature and at the same processing temperature in a shorter time as compared with the prior art. The effect of suppressing the by-product of the monomer can be obtained, and if the processing time and the processing temperature are the same, a more remarkable cyclic trimer by-product suppression effect can be obtained.

As described above, the polyester resin (A) is brought into contact with the phosphorus compound by the method for producing a polyester resin of the present invention. The polyester resin (B) obtained after the contact with the phosphorus compound is represented by the following formulas (1) to (3). Is a polyester resin satisfying
(1) 0.002 ≦ T ≦ 0.2
(2) P / (T + X) ≧ 4.0
(3) X ≧ 0
In the formulas (1) to (3), T is the content of titanium atoms per ton of the polyester resin (B) (mol / ton of resin), and X is other than the titanium atoms per ton of the polyester resin (B). Content of metal atoms (mol / ton of resin), P represents the content of phosphorus atoms per ton of polyester resin (B) (mol / ton of resin).

  Here, T is derived from the titanium compound used as a catalyst during the production of the polyester resin (A), and is the content of titanium atoms present in the polyester resin (B). 0.002 ≦ T ≦ 0.2, preferably 0.020 ≦ T ≦ 0.2, more preferably 0.060 ≦ T ≦ 0.100, and 0.070 ≦ T ≦ 0. More preferably, it is 0.090. If T is too large, P / (T + X) of the polyester resin (B) tends to be small, and the deactivation effect of titanium atoms and other metal atoms due to phosphorus atoms tends to be small. In addition to a tendency for the amount of by-products to increase and the retention rate of intrinsic viscosity to decrease, the color tone of the polyester resin (B) becomes yellowish. On the other hand, when T is too small, since the TA in obtaining the polyester resin (A) is small as described above, the cyclic trimer content of the polyester resin (B) is reduced due to the decrease in the polycondensation rate and the reduction rate of the cyclic trimer. The amount tends to increase, the amount of the cyclic trimer of the molded product obtained by melt molding increases, and the mold contamination tends to increase.

  X is derived from a compound of a metal atom other than titanium used when producing the polyester resin (A) as required, and contains a metal atom other than a titanium atom present in the polyester resin (B). It corresponds to the XA. Here, the metal atom other than the titanium atom means all the metal atoms of Group 1 to 15 of the periodic table other than the titanium atom as described above, for example, antimony, germanium, aluminum, zinc, tin, copper, lead, Examples include cobalt, iron, manganese, tungsten, zirconium, hafnium, beryllium, magnesium, calcium, strontium, barium, lithium, sodium, potassium, rubidium, and cesium. These metal atom compounds are usually used as a polycondensation catalyst, a co-catalyst, or an esterification catalyst during the production of the polyester resin (A). In the present invention, these metal atom compounds other than titanium are used. The amount used varies depending on the type, but is preferably as small as possible. The preferable value of X is 1.3, more preferably 0.400, and more preferably 0.300. Is more preferable, and 0.220 is particularly preferable. The lower limit of X depends on the catalytic ability of the titanium compound and the type of other metal compound used in combination, but is preferably 0, more preferably 0.004, and even more preferably 0.060. 0.070 is particularly preferable.

  When the value of X exceeds the above range and is excessive, the P / (T + X) of the polyester resin (B) tends to be small, and the amount of by-product of the cyclic trimer at the time of melt molding increases or is inherent. The retention of viscosity tends to decrease. On the other hand, if the value of X is too small, that is, XA is small, the effect of the metal atom compound used in combination cannot be achieved, and the polycondensation rate and the reduction rate of the cyclic trimer at the time of obtaining the polyester resin (A) are reduced. The cyclic trimer content of the polyester resin (B) tends to increase, the cyclic trimer content of the molded product obtained by melt molding increases, and mold contamination tends to increase.

Further, P is the content (mol / ton of resin) of phosphorus atoms per ton of the polyester resin (B), and if necessary, phosphorus atoms derived from the phosphorus compound used in the production of the polyester resin (A) And the phosphorus atom impregnated / attached on the polyester resin (A) or on the surface thereof when the polyester resin (A) and the phosphorus compound are brought into contact with each other. A preferable value of P satisfies the following (10), and more preferably satisfies the following (10 ′).
(10) 1.00 ≦ P ≦ 6.50
(10 ′) 3.20 ≦ P ≦ 5.80

  If P exceeds this range and is too small, P / (T + X) of the polyester resin (B) tends to be small, the amount of by-product of the cyclic trimer during melt molding increases, and the inherent viscosity retention rate Tends to decrease. On the other hand, if P exceeds this range and is too large, it takes time to contact the polyester resin (A) and the phosphorus compound, or it is necessary to increase the temperature at the time of contact, and the polyester resin (B) is melted. The effect of suppressing the amount of cyclic trimer by-product during molding and the effect of suppressing the decrease in intrinsic viscosity are not improved so much, and the productivity is deteriorated. Furthermore, the haze of the molded body tends to decrease.

  As described above, P / (T + X) is an index indicating the deactivation effect of the catalytic ability of titanium atoms and other metal atoms by phosphorus atoms. Therefore, the larger P / (T + X), the more the polyester resin (B). When melt molding, the phosphorus compound reacts with the metal compound, deactivates the catalytic ability of the metal compound, suppresses by-production of the cyclic trimer, or suppresses the decrease in intrinsic viscosity Conceivable. The value of P / (T + X) is 4.0 as the lower limit, preferably 10.0, more preferably 15.0, particularly preferably 20.0, and the upper limit. Is preferably 30.

If the value of P / (T + X) is too small beyond this range, that is, if the value of P is small, the amount of by-produced cyclic trimer at the time of melt molding increases or the retention rate of intrinsic viscosity decreases. It becomes a trend.
On the other hand, the value of P / (T + X) is too large exceeding this range, that is, in order to increase the value of P, it takes time to contact the polyester resin (A) with the phosphorus compound, or the temperature at the time of contact In addition, the effect of suppressing the amount of cyclic trimer by-product during the melt molding of the polyester resin (B) and the effect of suppressing the decrease in intrinsic viscosity are not improved so much, and the productivity is deteriorated.

  The polyester resin (A) to be brought into contact with the phosphorus compound in the production method of the present invention is basically produced by a conventional production method using a titanium compound as a catalyst. For example, first, a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component together with a copolymer component used as necessary are put into a slurry preparation tank and mixed with stirring. A raw material mixing step for forming a raw material slurry, and then an esterification reaction in which the raw material slurry is subjected to an esterification reaction in an esterification reaction tank under normal pressure to under pressure and under heating, is a polyester low molecular weight product that is an esterification reaction product. Get. Subsequently, the obtained polyester low molecular weight product is transferred to a polycondensation reaction tank, and in the presence of each compound such as the titanium compound catalyst, a melt polycondensation reaction is performed under heating under reduced pressure from normal pressure to gradually reduced pressure. A method of undergoing a melt polycondensation step, and a solid phase polycondensation step in which a solid phase polycondensation reaction is performed under heating as necessary is employed.

Hereinafter, the polyester resin (A) will be described in detail by taking as an example a method for producing the polyester resin through the esterification step. In the raw material mixing step, the raw material slurry is prepared by mixing 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 1.0 to 2.0, preferably 1.05 to 1.5, and more preferably 1.1 to 1.3. If the molar ratio of the diol component to the dicarboxylic acid component is less than the above range, the polycondensation reaction rate of the low molecular weight polyester obtained by the esterification reaction will be reduced. On the other hand, if it exceeds this range, the production of diethylene glycol will be reduced. The amount will increase.
The prepared raw material slurry is transferred to an esterification step including one or a plurality of esterification reaction tanks, and is subjected to an esterification reaction under normal pressure to pressure and under heating to obtain a polyester low molecular weight product.

As reaction conditions in the esterification reaction, in the case of a single esterification reaction tank, the temperature is usually about 240 to 280 ° C., and the relative pressure to atmospheric pressure is usually about 0 to 400 kPa (0 to 4 kg / cm ² G). The reaction time is about 1 to 10 hours under stirring. In the case of a plurality of esterification reaction tanks, the reaction temperature in the first stage esterification reaction tank is usually 240 to 270 ° C., preferably 245 to 265 ° C., and the relative pressure to atmospheric pressure is usually 5 to 300 kPa. (0.05 to 3 kg / cm ² G), preferably 10 to 200 kPa (0.1 to ² kg / cm ² G), and the reaction temperature in the final stage is usually 250 to 280 ° C., preferably 255 to 275 ° C. The relative pressure to atmospheric pressure is usually 0 to 150 kPa (0 to 1.5 kg / cm ² G), preferably 0 to 130 kPa (0 to 1.3 kg / cm ² G).

  Further, when the esterification reaction is performed using a plurality of esterification reaction tanks, the average esterification rate of the low molecular weight polyester (raw material dicarboxylic acid) in the esterification reaction tank immediately before the final stage esterification reaction tank. The ratio of the total carboxyl group of the acid component which has been esterified by reacting with the diol component) is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. It is preferable when reducing the terminal carboxyl group of resin (A). In the esterification reaction tank immediately before the final stage esterification reaction tank, in order to make the average esterification rate of the polyester low molecular weight substance the above, the reaction temperature and pressure in the esterification reaction tank are within the above ranges. The method of making it high is mentioned.

In the production method of the polyester resin (A) of the present invention, the low molecular weight between the esterification step and the melt polycondensation step is an esterification rate of 75% or more and a number average degree of polymerization of 3.0 to 10.0. It is preferable to add ethylene glycol in an amount of 4 to 40% by weight of the theoretical yield of the polyester resin (A) to the body esterification reaction product.
The average esterification rate of the low molecular weight polyester when adding ethylene glycol is preferably 75% or more, more preferably 90% or more, and particularly preferably 95% or more. If the esterification rate is less than the above range, it takes time for the esterification reaction with the additionally added ethylene glycol, and ethylene glycol is dehydrated and condensed by acid catalysis of the terminal carboxyl group, and diethylene glycol is by-produced.

  Moreover, it is preferable that the number average polymerization degree of the polyester low molecular weight body at the time of additional addition of ethylene glycol shall be 3.0-10.0. In the continuous esterification reaction method, the number average degree of polymerization is more preferably 4.0 to 8.0, particularly preferably 5.0 to 7.0, and batchwise esterification reaction method. Is more preferably 5.0 to 9.0, and particularly preferably 6.0 to 8.0. If the number average degree of polymerization is less than the above range, the reaction product that is transferred to the melt polycondensation step and submerged under reduced pressure tends to sublimate and volatilize, causing troubles such as blockage of the distillation system, and polycondensation. It takes a long time to cause a deterioration in color tone and a decrease in productivity. On the other hand, if the above range is exceeded, the total number of terminals will decrease, the proportion of carboxyl groups in the total number of terminals will increase, and the addition of ethylene glycol will not lead to a reduction in terminal carboxyl groups. Become.

The additional addition of ethylene glycol is performed on the polyester low molecular weight substance which is an esterification reaction product under a pressure of a temperature of 250 ° C. or higher and lower than 265 ° C. and a pressure of 1.0 × 10 ⁵ Pa relative to atmospheric pressure to atmospheric pressure. Preferably, the temperature is 255 ° C. or more and less than 265 ° C., and the pressure is more preferably a pressure of 0.5 × 10 ⁵ Pa relative to normal pressure to atmospheric pressure, It is particularly preferable that the pressure is a relative pressure of 0.3 × 10 ⁵ Pa relative to normal pressure to atmospheric pressure.

  If the temperature is lower than the above range, the addition of ethylene glycol may cause the system to cool and the reaction product may solidify.On the other hand, if it exceeds the above range, evaporation and volatilization of the additional ethylene glycol may occur. In addition, the ethylene carboxyl tends to be dehydrated and condensed due to the acid catalysis of the terminal carboxyl group, and diethylene glycol tends to be easily formed. Further, when the pressure is less than the above range, the additional added ethylene glycol is apt to evaporate and volatilize. On the other hand, when it exceeds the above range, ethylene glycol tends to be dehydrated and condensed due to the acid catalysis of the terminal carboxyl group, and diethylene glycol tends to be generated. It becomes.

  In the method for producing a polyester resin (A) of the present invention, the additional addition of ethylene glycol is between the esterification step and the melt polycondensation step, and the ester satisfying the esterification rate and the number average degree of polymerization The reaction is carried out at any one or a plurality of locations under the temperature and pressure ranges from the esterification step to before the pressure reduction is applied in the melt polycondensation step. The esterification reaction product is preferably applied to the esterification reaction product under normal pressure after passing through the esterification step and before being subjected to reduced pressure in the melt polycondensation step.

Furthermore, the amount of ethylene glycol to be added is preferably 4 to 40% by weight of the theoretical yield of the polyester resin (A). However, when the additional addition of ethylene glycol is performed in the esterification step, 4 to 20%. More preferably, it is made into weight%, and it is especially preferable to set it as 4-15 weight%. If the additional addition amount is less than the above range, the terminal carboxyl group tends to increase. On the other hand, if it exceeds the above range, the degree of polymerization is reduced due to cooling solidification or depolymerization in the system.
As the addition form of the additional ethylene glycol, it may be a pure ethylene glycol, a solvent or a dispersion medium such as a copolymer component, a catalyst, and other additives, an esterification step, or a polycondensation step. It may be ethylene glycol distilled off in or a mixture containing the same.

  In the production method of the polyester resin (A) of the present invention, the amount of terminal carboxyl groups of the polyester resin obtained after melt polycondensation by performing the esterification method including the additional addition of ethylene glycol as described above will be described later. Such a small value can be used. Particularly when solid-phase polycondensation is performed, the reduction rate of the cyclic trimer in the solid-phase polycondensation can be increased by reducing the amount of the terminal carboxyl group, so that the cyclic terpolymers of the polyester resins (A) and (B) can be increased. The content of the polymer can be lowered, the amount of the cyclic trimer of the molded product obtained by melt molding of the polyester resin (B) is reduced, the mold contamination is suppressed, and the self-acid catalyst by the terminal carboxyl group Since the hydrolysis action is reduced, the decrease in intrinsic viscosity during melt molding is reduced.

In the production method of the polyester resin (A) of the present invention, the polyester low molecular weight product which is the esterification reaction product obtained as described above is subsequently subjected to a melt polycondensation step equipped with one or a plurality of polycondensation reaction tanks. In the presence of a titanium compound catalyst, a melt polycondensation reaction is carried out under heating under reduced pressure from normal pressure to gradually reduced pressure.
In the melt polycondensation reaction, a single polycondensation reaction tank or a plurality of polycondensation reaction tanks are connected in series, for example, a fully mixed reactor in which the first stage includes a stirring blade, the second stage, and The third stage is carried out using a multistage reaction apparatus comprising a horizontal plug flow reactor equipped with a stirring blade while distilling the produced ethylene glycol out of the system under reduced pressure.

  As for the reaction conditions in the melt polycondensation, in the case of a single polycondensation reaction tank, the absolute pressure is usually 1.3 to 0. The reaction time is set to about 013 kPa (10 to 0.1 Torr) and the reaction time is about 1 to 20 hours under stirring. In the case of a plurality of polycondensation reaction tanks, the reaction temperature in the first stage polycondensation reaction tank is usually 250 to 290 ° C., preferably 260 to 280 ° C., and the absolute pressure is usually 65 to 1.3 kPa ( 500 to 10 Torr), preferably 26 to 2 kPa (200 to 15 Torr), the reaction temperature in the final stage is usually 265 to 300 ° C., preferably 270 to 295 ° C., and the absolute pressure is usually 1.3 to 0.013 kPa ( 10 to 0.1 Torr), preferably 0.65 to 0.065 kPa (5 to 0.5 Torr). As reaction conditions in the intermediate stage, those intermediate conditions are selected. For example, in a three-stage reactor, the reaction temperature in the second stage is usually 265 to 295 ° C., preferably 270 to 285 ° C., and the absolute pressure is Usually, it is 6.5 to 0.13 kPa (50 to 1 Torr), preferably 4 to 0.26 kPa (30 to 2 Torr).

The polyester resin (A) in the present invention is produced by using a titanium compound as a catalyst as described above. Further, in order to improve the polycondensation reaction rate and the cyclic trimer reduction rate at the time of production, magnesium is used. It is preferable that a compound is added and subjected to a melt polycondensation reaction, particularly preferably a melt polycondensation using the titanium compound, the magnesium compound, and a phosphorus compound as an auxiliary agent / stabilizer. .
As the titanium compound as the catalyst, the above-described titanium compound is used.
Specific examples of the magnesium compound include magnesium oxide, magnesium hydroxide, magnesium alkoxide, magnesium acetate, magnesium carbonate, and hydrates thereof, among which magnesium acetate and hydrates thereof are preferable.

  Specific examples of the phosphorus compound include orthophosphoric acid, polyphosphoric acid, trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris ( Triethylene glycol) phosphate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, phosphate ester such as triethylphosphonoacetate, etc. 5 Divalent phosphorus compounds and phosphorous acid, hypophosphorous acid, trimethyl phosphite, diethyl phosphite, triethyl phosphite Phosphites such as phyto, trisdodecyl phosphite, trisnonyl decyl phosphite, ethyl diethyl phosphonoacetate, triphenyl phosphite, trivalent phosphorus compounds such as metal salts such as lithium, sodium and potassium, hypophosphorous Among them, in view of polycondensation rate controllability, a phosphate ester of a pentavalent phosphorus compound is preferable, trimethyl phosphate, ethyl acid phosphate, triethylphosphonoacetate is more preferable, and ethyl acid phosphate is more preferable. Particularly preferred.

As a polyester resin (A) manufactured by this invention, what was manufactured using the magnesium compound and a phosphorus compound together as mentioned above with a titanium compound catalyst is preferable, The titanium atom content in the polyester resin (A) is preferable. When TA (mole / resin ton), magnesium atom content is MA (mole / resin ton), and phosphorus atom content is PA (mole / resin ton), TA, PA, and MA are represented by the following formulas (4) to (4): It is preferable to satisfy (8).
(4) 0.020 ≦ TA ≦ 0.200
(5) 0.040 ≦ MA ≦ 0.400
(6) 0.020 ≦ PA ≦ 0.300
(7) 0.50 ≦ MA / PA ≦ 3.00
(8) 0.20 ≦ MA / TA ≦ 4.00

Further, the content TA as a titanium atom derived from the titanium compound in the polyester resin (A) preferably satisfies the following formula (4) as described above, but satisfies the following formula (4 ′). Is more preferable, and it is particularly preferable that the following formula (4 ″) is satisfied. When TA is less than the left side of the following formula, the polycondensation rate and the reduction rate of the cyclic trimer tend to decrease when solid phase polycondensation is performed. Tends to be yellowish, and P / (T + X) of the polyester resin (B) obtained by contacting the obtained polyester resin (A) with a phosphorus compound tends to be small. There is a tendency that the amount of by-product of the monomer increases or the retention of intrinsic viscosity decreases.
(4) 0.020 ≦ TA ≦ 0.200
(4 ′) 0.060 ≦ TA ≦ 0.100
(4 '') 0.070 ≦ TA ≦ 0.090

The content MA as a magnesium atom derived from the magnesium compound in the polyester resin (A) preferably satisfies the following formula (5), more preferably satisfies the following formula (5 ′). It is particularly preferable to satisfy (5 ″). When MA is less than the left side of the following formula, when solid phase polycondensation is performed, the polycondensation rate and the reduction rate of the cyclic trimer tend to decrease. When polycondensation is performed, the polycondensation rate and the reduction rate of the cyclic trimer tend to decrease, the color tone and thermal stability of the polyester resin tend to decrease, and the resulting polyester resin (A) is converted into a phosphorus compound. P / (T + X) of the polyester resin (B) obtained by contact with the resin tends to be small, the amount of by-product of the cyclic trimer at the time of injection molding increases, or the retention rate of intrinsic viscosity decreases. Tend to.
(5) 0.040 ≦ MA ≦ 0.400
(5 ′) 0.060 ≦ MA ≦ 0.300
(5 ″) 0.110 ≦ MA ≦ 0.220

Further, the content PA as a phosphorus atom derived from the phosphorus compound contained in the polyester resin (A) preferably satisfies the following formula (6), and more preferably satisfies the following formula (6 ′). It is particularly preferable that the following formula (6 ″) is satisfied, and it is most preferable that the following formula (6 ′ ″) is satisfied. If PA is less than the left side of the following formula, the thermal stability as a polyester resin tends to be reduced, whereas if it exceeds the right side, the polycondensation rate in solid phase polycondensation and the reduction rate of cyclic trimer are reduced. Tend to.
(6) 0.020 ≦ PA ≦ 0.300
(6 ′) 0.050 ≦ PA ≦ 0.200
(6 ″) 0.080 ≦ PA ≦ 0.180
(6 ′ ″) 0.090 ≦ PA ≦ 0.150

  Further, in the polyester resin (A), it is preferable that the TA, MA, and PA satisfy the formulas (4) to (6) and the MA / PA satisfies the following formula (7). It is more preferable that the following formula (7 ′) is satisfied, and it is particularly preferable that the following formula (7 ″) is satisfied. Further, MA / TA preferably satisfies the following formula (8), more preferably satisfies the following formula (8 ′), and particularly preferably satisfies the following formula (8 ″). Most preferably, (8 '' ') is satisfied. When MA / PA and MA / TA are less than the left side and the right side of the following formula, in any case, the polycondensation rate and the reduction rate of the cyclic trimer are reduced when solid phase polycondensation is performed, and The thermal stability as a polyester resin tends to decrease.

(7) 0.50 ≦ MA / PA ≦ 3.00
(7 ′) 0.90 ≦ MA / PA ≦ 1.80
(7 '') 1.10 ≦ MA / PA ≦ 1.50
(8) 0.20 ≦ MA / TA ≦ 4.00
(8 ′) 0.50 ≦ MA / TA ≦ 3.50
(8 ″) 1.00 ≦ MA / TA ≦ 2.90
(8 ''') 1.50 ≦ MA / TA ≦ 2.40

Furthermore, in the polyester resin (A), the TA, MA, and PA satisfy the formulas (4) to (8), and the PA / MA / TA satisfies the following formula (8-1). It is more preferable that the following formula (8-1 ′) is satisfied, and it is particularly preferable that the following formula (8-1 ″) is satisfied. When PA / MA / TA is less than the left side of the following formula and exceeds the right side, the polycondensation rate and the reduction rate of the cyclic trimer are reduced when solid phase polycondensation is performed. The thermal stability as a resin tends to decrease.
(8-1) 3.0 ≦ PA / MA / TA ≦ 19.0
(8-1 ′) 5.0 ≦ PA / MA / TA ≦ 15.0
(8-1 ″) 8.0 ≦ PA / MA / TA ≦ 12.0

  In the polyester resin (A) in the present invention, by setting the content and ratio as each atom derived from the titanium compound, magnesium compound, and phosphorus compound as described above, a relatively small amount of the titanium compound catalyst. Is used to obtain a polyester resin (A) at a sufficient polycondensation rate or cyclic trimer reduction rate, and P / (T + X) of the polyester resin (B) obtained after contacting the resin (A) with a phosphorus compound. As a result, it is possible to suppress a reduction in the amount of by-products and intrinsic viscosity of the cyclic trimer during melt molding of the resin (B). In addition, the content of diethylene glycol, the content of acetaldehyde as a resin and a molded product, and the fragrance retention property can also be made preferable.

  The addition of the titanium compound and the magnesium compound to the reaction system is based on the low molecular weight esterification reaction product having an esterification rate of 75% or more and a number average degree of polymerization of 3.0 to 10.0. It is preferable to carry out the reaction on a reaction product having an esterification rate of 90% or more. In addition, the phosphorus compound may be added to the reaction system from the raw material mixing step to the melt polycondensation step as described above, but is preferably added in the raw material slurry preparation step.

  As a specific addition process of each of these compounds to the reaction system, for example, the titanium compound is a final stage esterification reaction tank in a multistage reaction apparatus or a transfer stage from the esterification reaction tank to the melt polycondensation process. The magnesium compound is preferably added to the final stage of the esterification reaction tank in the multistage reactor, and the addition order of both is preferably the magnesium compound and then the titanium compound. Moreover, it is preferable to add a phosphorus compound to the slurry preparation tank of a raw material mixing process, or the esterification reaction tank of the 1st stage, and it is especially preferable to add to a slurry preparation tank.

The polyester resin obtained by the melt polycondensation in the production method of the polyester resin (A) of the present invention has an intrinsic viscosity ([η ₁ ]) as a solvent of a mixture of phenol / tetrachloroethane (weight ratio 1/1), The value measured at 30 ° C. (see Examples) is preferably 0.35 to 0.75 dl / g, more preferably 0.50 to 0.65 dl / g. If the intrinsic viscosity ([η ₁ ]) is less than the above range, the extractability described later from the polycondensation reaction tank tends to be poor and the operability tends to decrease. It tends to be difficult to reduce the cyclic trimer content and the acetaldehyde content.

The polyester resin obtained by the melt polycondensation is usually extracted in a strand form from an outlet provided in the bottom of the polycondensation reaction tank, and is cooled with water or after water cooling, and then cut with a cutter or the like to form pellets, chips A granular material such as a shape. In the present invention, the polyester resin (A) may be produced by solid-phase polycondensation of the granules after melt polycondensation, if necessary. That is, the granular material after melt polycondensation is usually 100 kPa (1 kg / cm ² G) or less, preferably 20 kPa (0) as a relative pressure with respect to atmospheric pressure in an inert gas atmosphere such as nitrogen, carbon dioxide, and argon. .2 kg / cm ² G) under a pressure of usually about 5 to 30 hours, or as an absolute pressure, usually 6.5 to 0.013 kPa (50 to 0.1 Torr), preferably 1.3 to 0.065 kPa. Solid phase polycondensation can be carried out by heating at a temperature of usually about 190 to 230 ° C., preferably 195 to 225 ° C. under reduced pressure of (10 to 0.5 Torr) for usually about 1 to 20 hours. By this solid phase polycondensation, the degree of polymerization can be further increased, and the amount of by-products such as cyclic trimer and acetaldehyde can be reduced.

  In the production method of the polyester resin (A) of the present invention, when solid-phase polycondensation is performed on the granules after melt polycondensation, prior to solid-phase polycondensation, in an inert gas atmosphere, in a water vapor atmosphere, or in water vapor content It is preferable to crystallize the resin granule surface by heating at 120 to 200 ° C., preferably 130 to 190 ° C. for about 1 minute to 4 hours in an inert gas atmosphere. Among these, heating in a steam atmosphere is preferable because it can improve the crystallization speed of the resin granules and further reduce the acetaldehyde content of the resulting polyester resin (A).

In the production method of the polyester resin (A) of the present invention, the polyester resin (A) obtained by the production method as described above has a terminal carboxyl group amount of 20 equivalents / ton or less and an intrinsic viscosity of 0. 50 to 1.50 dl / g and the cyclic trimer content are preferably 0.5% by weight or less.
The amount of the terminal carboxyl group of the polyester resin (A) in the present invention is preferably 20 equivalents / toner or less, more preferably 15 equivalents / toner or less, and more preferably 10 equivalents / toner or less. Is more preferable. When the amount of the terminal carboxyl group exceeds the above range, the content of the cyclic trimer of the polyester resin (B) after the contact treatment with the phosphorus compound of the polyester resin (A) increases, and mold contamination occurs when molding a bottle or the like. In addition, it tends to occur, and the inherent viscosity at the time of melt molding tends to decrease due to the self-acid catalyzed hydrolysis action by the terminal carboxyl group.

The intrinsic viscosity ([η ₂ ]) of the polyester resin (A) in the present invention is a value measured at 30 ° C. (see Examples) using a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent. Is preferably 0.50 to 1.50 dl / g, more preferably 0.60 to 1.00 dl / g, and still more preferably 0.70 to 0.90 dl / g. When the intrinsic viscosity is less than the above range, when the polyester resin (B) after the contact treatment with the phosphorus compound of the polyester resin (A) is used as a molded body such as a bottle, the mechanical strength thereof is decreased, If it exceeds 1, the melt formability tends to decrease, or the by-product amount of the cyclic trimer during melt molding tends to increase.

  Furthermore, the cyclic trimer content of the polyester resin (A) in the present invention is preferably 0.5% by weight or less, more preferably 0.4% by weight or less, and 0.35% by weight. More preferably, it is more preferably 0.30% by weight or less. When the content of the cyclic trimer exceeds the above range, the mold is easily contaminated during molding of the polyester resin (B) bottle after the contact treatment with the phosphorus compound of the polyester resin (A), and the molded body is transparent. This will cause a decrease in appearance and the like.

In the production method of the present invention, the polyester resin (B) is produced by bringing the polyester resin (A) obtained as described above into contact with a phosphorus compound as described above.
As described above, the polyester resin (B) obtained by the production method of the present invention satisfies the following formulas (1) to (3).
(1) 0.002 ≦ T ≦ 0.2
(2) P / (T + X) ≧ 4.0
(3) X ≧ 0
In the formulas (1) to (3), T is the content of titanium atoms per ton of the polyester resin (B) (mol / ton of resin), and X is other than the titanium atoms per ton of the polyester resin (B). Content of metal atom (mol / ton of resin), P represents the content of phosphorus atom per ton of polyester resin (B) (mol / ton of resin).

  Here, T is preferably 0.020 ≦ T ≦ 0.200, more preferably 0.060 ≦ T ≦ 0.100, and further preferably 0.070 ≦ T ≦ 0.090. preferable. When T is large, the value of P / (T + X) of the polyester resin (B) tends to be small, and the amount of by-produced cyclic trimer at the time of melt molding increases or the retention rate of intrinsic viscosity decreases. In addition, the color tone of the polyester resin (B) becomes yellowish. On the other hand, if T is small, the cyclic trimer content of the polyester resin (B) tends to increase, and the productivity of the polyester resin and the cyclic trimer amount of the molded product obtained by melt molding increase. Contamination tends to increase.

  X is the content of metal atoms other than titanium atoms present in the polyester resin (B), and the metal atoms other than titanium atoms are the same as in the periodic table groups 1 to 15 other than titanium atoms as described above. All metal atoms, for example, antimony, germanium, aluminum, zinc, tin, copper, lead, cobalt, iron, manganese, tungsten, zirconium, hafnium, beryllium, magnesium, calcium, strontium, barium, lithium, sodium, potassium, Examples include rubidium and cesium. These metal atom compounds are usually used frequently as polycondensation catalysts, cocatalysts, transesterification catalysts, and esterification catalysts in the production of polyester resins. In the present invention, the use of metal atoms other than titanium is not used. The amount of X is preferably as small as possible, and the preferable value of X is 1.3, more preferably 0.400, even more preferably 0.300, and more preferably 0.220. The lower limit is preferably 0, more preferably 0.004, even more preferably 0.060, and particularly preferably 0.070. When X is large, the value of P / (T + X) of the polyester resin (B) tends to be small, the amount of by-product of the cyclic trimer at the time of melt molding increases, or the retention rate of intrinsic viscosity decreases. Tend to. On the other hand, when X is small, the cyclic trimer content of the polyester resin (B) tends to increase, the productivity of the resin and the cyclic trimer content of the molded product obtained by melt molding increase, and mold contamination is increased. There is a tendency to increase.

P is the content of phosphorus atoms per ton of the polyester resin (B) (mol / ton of resin), and the preferred P value is 1.00 ≦ P ≦ 6.50, more preferably 3. 20 ≦ P ≦ 5.80.
When P is small, the value of P / (T + X) of the polyester resin (B) tends to be small, the amount of by-product of the cyclic trimer at the time of melt molding increases, or the retention rate of intrinsic viscosity decreases. Tend to. On the other hand, when P is larger than this, when obtaining the polyester resin (B), it takes time to contact the raw material polyester resin (A) and the phosphorus compound, or it is necessary to increase the temperature at the time of contact. On the other hand, the effect of suppressing the cyclic trimer by-product amount during melt molding and the effect of suppressing the decrease in intrinsic viscosity are not improved so much, and the productivity of the polyester resin (B) deteriorates.

  Further, the value of P / (T + X) represents the ratio between the P and the sum of T and X, that is, the amount of metal atoms present in the polyester resin (B), and the value of P / (T + X). When the polyester resin (B) is melt-molded, the phosphorus compound reacts with the metal compound to deactivate the catalytic ability of the metal compound and suppress the by-production of the cyclic trimer. It is considered that the decrease in viscosity is suppressed. The value of P / (T + X) is 4.0 as the lower limit, preferably 10.0, more preferably 15.0, particularly preferably 20.0, and the upper limit. Is preferably 30. When the value of P / (T + X) is small, the by-product amount of the cyclic trimer at the time of melt molding tends to increase, or the retention rate of intrinsic viscosity tends to decrease. On the other hand, when the value of P / (T + X) is larger than this, when obtaining the polyester resin (B), it takes time to contact the raw material polyester resin (A) with the phosphorus compound, or the temperature at the time of contact. On the other hand, the effect of suppressing the cyclic trimer by-product amount during melt molding and the effect of suppressing the decrease in intrinsic viscosity are not improved so much, and the productivity of the polyester resin (B) is deteriorated. .

In the production method of the present invention, a suitable polyester resin (A) that is contact-treated with a phosphorus compound is obtained by using a magnesium compound at the time of production, and is derived from the magnesium compound in the polyester resin (B). The content (mol / ton of resin) of magnesium atoms per ton of the polyester resin (B) preferably satisfies the following formula (9), but more preferably satisfies the following formula (9 ′). It is particularly preferable that the following formula (9 ″) is satisfied. If M is outside the range of the following formula, the cyclic trimer content tends to increase, the productivity of the resin and the cyclic trimer amount of the molded product obtained by melt molding increase, and mold contamination In addition to the tendency to increase, the color tone and thermal stability as a polyester resin also tend to decrease. In particular, when M is large, the P / (T + X) of the polyester resin (B) tends to be small, and the injection The by-product amount of the cyclic trimer at the time of molding tends to increase, or the inherent viscosity retention rate tends to decrease.
(9) 0.040 ≦ M ≦ 0.400
(9 ′) 0.060 ≦ M ≦ 0.300
(9 ″) 0.110 ≦ M ≦ 0.220

In the present invention, the metal content in the polyester resin (B) is preferably such that the content P as a phosphorus atom satisfies the following formula (10), but satisfies the following formula (10 ′). Further preferred. If the content P as a phosphorus atom is less than the left side of the following formula, the amount of cyclic trimer produced during melt molding tends to increase, while if it exceeds the right side, the haze of the molded body tends to decrease. Become.
(10) 1.00 ≦ P ≦ 6.50
(10 ′) 3.20 ≦ P ≦ 5.80

  In the present invention, the polyester resin (B) obtained from the polyester resin (A) produced by using the magnesium compound as described above has a metal content therein, a content T as a titanium atom, and a magnesium atom. Is preferably satisfied with the following formula (11 ′), more preferably satisfies the following formula (11 ′), and particularly preferably satisfies the following formula (11 ″). It is most preferable to satisfy '' '). When the ratio of magnesium atom to titanium atom (M / T) is outside the range of the following formula, the thermal stability of the resulting polyester resin (B) tends to be lowered.

(11) 0.20 ≦ M / T ≦ 4.00
(11 ′) 0.50 ≦ M / T ≦ 3.50
(11 ″) 1.00 ≦ M / T ≦ 2.90
(11 ′ ″) 1.50 ≦ M / T ≦ 2.40

  The amount of the terminal carboxyl group of the polyester resin (B) obtained by the production method of the present invention is preferably 20 equivalents / toner or less, more preferably 15 equivalents / toner or less, and more preferably 10 equivalents / resin. More preferably, it is less than tons. If the amount of the terminal carboxyl group exceeds the above range, the cyclic trimer content increases, and mold contamination tends to occur during molding of bottles and the like, and melt molding due to self-acid catalyzed hydrolysis by the terminal carboxyl group Intrinsic viscosity at the time tends to decrease.

In the polyester resin (B) in the present invention, the content of each atom represented by T, P and X in the resin satisfies the above formulas (1) to (3), and the intrinsic viscosity of the resin is 0.50. ˜1.50 dl / g, cyclic trimer content is 0.5% by weight or less, and cyclic trimer increase amount of the molded product obtained by injection molding at 290 ° C. is 0.05% by weight The following is preferable.
Here, the intrinsic viscosity is a value measured at 30 ° C. using a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent, and is more preferably 0.60 to 1.00 dl / g. More preferably, it is .65 to 0.90 dl / g, and particularly preferably 0.70 to 0.80 dl / g. If the intrinsic viscosity is less than the above range, the mechanical strength as a molded article such as a bottle tends to be reduced. On the other hand, if it exceeds the above range, the melt moldability is inferior, and the amount of cyclic trimer produced at the time of molding. Tend to increase.

The amount of the cyclic trimer in the polyester resin (B) is preferably 0.5% by weight or less, more preferably 0.4% by weight or less, and 0.35% by weight or less. More preferably, it is particularly preferably 0.30% by weight or less, and most preferably 0.25% by weight or less. When the content of the cyclic trimer exceeds the above range, mold contamination or the like is likely to occur during molding of a bottle or the like, resulting in deterioration of the appearance such as transparency of the molded body.
Further, the cyclic trimer increase amount of the molded product obtained by injection molding at 290 ° C. is the cyclic trimer content CT ₁ of the molded product and the cyclic trimer content CT ₀ of the resin before injection molding. [CT ₁ −CT ₀ ], and the cyclic trimer increase amount is preferably 0.05% by weight or less, and more preferably 0.03% by weight or less. When exceeding this range, mold contamination or the like is likely to occur during the molding of a bottle or the like, leading to a decrease in the appearance of the molded body.

The polyester resin (B) preferably has an inherent viscosity retention of 94% or more when injection molded at 290 ° C.
Here, the retention ratio (%) of the intrinsic viscosity means that the intrinsic viscosity of the polyester resin is [η ₀ ], and the intrinsic viscosity of the molded article obtained by injection molding the polyester resin at 290 ° C. is (η). [η] / [η ₀ ]) × 100.
If the retention rate of the intrinsic viscosity is less than the above range, the mechanical strength of a molded body such as a bottle tends to decrease, or the dimensional stability of the molded body tends to decrease.

In addition, the polyester resin (B) in the present invention has a color coordinate b value of Hunter's color difference formula by the Lab color system of 4.0 or less in order to suppress a yellowish color tone as a molded body such as a bottle. Preferably, it is 3.0 or less, more preferably 2.0 or less. The lightness index L value is preferably 85 or more, and more preferably 88 or more.
In order to set the color coordinate b value of the polyester resin (B) within the above range, a so-called organic toning agent may be added. Examples of the organic toning agent include Solvent Blue 104, Examples thereof include dyes such as Solvent Red 135, Solvent Violet 36, Pigment Blue 29, 15: 1, 15: 3, Pigment Red 187, 263, Pigment Violet 19, and the like. In order to suppress a decrease in the value, it is preferably 3.0 ppm by weight or less, more preferably 2.0 ppm by weight or less, particularly preferably 1.5 ppm by weight or less, 1.0 wt. Most preferably, it is at most ppm.
The organic toning agent may be added at any stage from the polyester resin production stage to the molding stage. The addition of the organic toning agent allows the lightness index L value to be maintained at 80 or more, more preferably 83 or more, and the color coordinate b value to be 1.0 or less.

  The polyester resin (B) of the present invention preferably has a haze of 5.0% or less, more preferably 3.0% or less, in a molded plate having a thickness of 5.0 mm which is injection-molded at 280 ° C. preferable. Further, the haze of a molded plate having a thickness of 5.0 mm which is injection-molded at 270 ° C. is preferably 40% or less, more preferably 20% or less, and particularly preferably 10% or less. As for the haze of the molded plate, a Nippon Denshoku haze meter “NDH-300A” was used for a molded plate having a thickness of 5.0 mm molded at a predetermined temperature (part B of the stepped molded plate shown in FIG. 1). Can be measured.

The polyester resin (B) of the present invention preferably has an acetaldehyde content of 3.0 ppm by weight or less from the viewpoint of suppressing adverse effects on the flavor, aroma, etc. of the contents as a molded article such as a bottle, More preferably, it is 2.0 ppm by weight or less. The acetaldehyde content in the molded article injection-molded at 280 ° C. is preferably 23 ppm by weight or less, more preferably 20 ppm by weight or less, particularly preferably 15 ppm by weight or less, and 10 ppm by weight. Most preferably:
Here, the content of acetaldehyde was sealed by charging 5.0 g of a polyester resin (PET) chip together with 10.0 ml of pure water in a microbomb having an internal volume of 50 ml under a nitrogen atmosphere. After heating this at 160 ° C. for 2 hours, acetaldehyde in water was quantified using a GC-14A gas chromatograph manufactured by Shimadzu Corporation with isobutyraldehyde as an internal standard, and expressed as a ratio (weight ppm) per PET weight. is there.

  The polyester resin (B) of the present invention thus obtained is molded into a preform by, for example, injection molding or by injection blow molding (injection blow molding) or by extrusion molding. By blow molding the extruded parison (extrusion blow molding), forming into a bottle or the like, forming into a sheet by extrusion molding, then forming into a tray or container by thermoforming, or stretching the sheet It becomes a film or the like, and is particularly useful as a packaging material for food or drink. Among these, it is suitable for molding a bottle by injection molding and a blow molding method (injection blow molding) in which a preform is biaxially stretched by injection molding, and is particularly suitable for injection blow molding. For example, containers for liquid seasonings such as carbonated drinks, alcoholic drinks, soy sauce, sauces, mirin, dressings, etc., and containers such as fruit juice drinks, vitamin drinks, flavor teas, mineral water drinks, etc. And is preferably used.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
Various measurement methods used in the following examples and comparative examples are shown below.

<Metal atom content>
A 5 g polyester resin sample was incinerated with hydrogen peroxide in the presence of sulfuric acid in a conventional manner, completely decomposed, and then adjusted to 50 ml with distilled water. A plasma emission spectrometer (ICP-AES manufactured by JOBIN YVON) JY46P type "), and converted to a molar amount in 1 ton of polyester resin.

<Intrinsic viscosity (dl / g)>
When the polyester resin is in the form of pellets, 0.25 g of the resin sample obtained by freeze-pulverizing the pellets. In the case of a molded body (preform), the resin sample is cut out to the same size as the pellets and then freeze-ground. 0.25 g of a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent and a concentration (c) of 1.0 g / dl. In the case of a solid phase polycondensation resin, it was dissolved by holding at 120 ° C. for 30 minutes. Then, the relative viscosity (η _rel ) with the stock solution was measured at 30 ° C. using the Ubbelohde capillary viscosity tube for the obtained solution, and the specific viscosity (η _sp ) determined from this relative viscosity (η _rel ) −1. ) And the concentration (c) (η _sp / c), and the ratio (c) is 0.5 g / dl, 0.2 g / dl, and 0.1 g / dl. η _sp / c) was determined, and from these values, the ratio (η _sp / c) when the concentration (c) was extrapolated to 0 was determined as the intrinsic viscosity (dl / g).

<Amount of terminal carboxyl group>
After pulverizing the polyester resin chip, it was dried at 140 ° C. for 15 minutes with a hot air drier, cooled to room temperature in a desiccator, 0.1 g was accurately weighed and collected in a test tube, 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. One to two drops of phenol red indicator were added to this solution, and the mixture was titrated with 0.1N sodium hydroxide in benzyl alcohol with stirring while blowing dry nitrogen gas, and the end point was reached when the color changed from yellow to red. Further, as a blank, the same operation was performed without a polyester resin sample, and the acid value was calculated by the following formula.

(Equation 1)
Acid value (mol / ton of resin) = (A−B) × 0.1 × f / W
[In the formula, A is the amount of benzyl alcohol solution of 0.1N sodium hydroxide required for titration (μl), B is the amount of benzyl alcohol solution of 0.1N sodium hydroxide required for titration with a blank. The amount (μl), W is the amount (g) of the polyester resin sample, and f is the titer of a benzyl alcohol solution of 0.1N sodium hydroxide. ]

The titer (f) of 0.1N sodium hydroxide in benzyl alcohol solution was obtained by taking 5 ml of methanol in a test tube and adding 1 to 2 drops of phenol red ethanol solution as an indicator. Titrate with 0.4 ml of sodium benzyl alcohol solution to the color change point, then add 0.2 ml of 0.1N aqueous hydrochloric acid solution with known titer as standard solution, and add again benzyl hydrate of 0.1N sodium hydroxide. Titration to the color change point with an alcohol solution. (The above operation was performed while blowing dry nitrogen gas.) The titer (f) was calculated by the following equation.
(Equation 2)
Titer (f) = Titer of 0.1N hydrochloric acid aqueous solution × [Amount of collected 0.1N hydrochloric acid aqueous solution (μl) / Titration of 0.1N sodium hydroxide in benzyl alcohol solution (μl)]

<Esterification rate>
The sample is pulverized in a mortar, 1.0 g of the sample is precisely weighed in a beaker, 40 ml of dimethylformamide is added thereto, and the mixture is dissolved by heating at 180 ° C. for 20 minutes with stirring. Wash the walls and cool to room temperature. This solution was titrated with a methanol solution of 0.1 N potassium hydroxide using a complex pH electrode “EA-120” with a potentiograph “E-536 type” automatic titrator manufactured by Metrohm. A methanol solution of 0.1N potassium hydroxide was prepared and standardized by the method of JIS K8006. A titration amount [A (ml)] obtained from the inflection point of the obtained titration curve, a factor [f ₁ ] of a 0.1N potassium hydroxide methanol solution prepared, standardized and calculated by the above-mentioned method, and From the sample weight [W (g)], the amount of free terminal carboxyl groups [AV (meq / g)] was determined by the following formula.
(Equation 3)
AV (meq / g) = {A × f ₁ × (1/10)} / W

Next, 0.3 g of the sample pulverized in a mortar was precisely weighed into an Erlenmeyer flask, and 20 ml of 0.5N potassium hydroxide ethanol solution was added with a whole pipette, and further 10 ml of pure water was added, and a reflux condenser was set. The sample was hydrolyzed by heating at reflux for 2 hours on a plate heater with a surface temperature of 200 ° C. with occasional stirring. The sample solution at this time is transparent. After allowing to cool, titration was performed with 0.5N aqueous hydrochloric acid using phenolphthalein as an indicator. Here, an ethanol solution of 0.5N potassium hydroxide and a 0.5N hydrochloric acid aqueous solution were prepared and standardized by the method of JIS K8006. Also, phenolphthalein was used in which 1 g was dissolved in 90 ml of ethanol and the volume was adjusted to 100 ml with pure water. Moreover, it titrated also in the blank state which does not put a sample on the same conditions. At that time, the titration volume of the sample [Vs (ml)], the blank titration volume [Vb (ml)], the factor [f ₂ ] of the 0.5N hydrochloric acid aqueous solution prepared, standardized and calculated by the above method, and From the sample weight [W (g)], the amount of carboxyl groups derived from all carboxylic acids [SV (meq / g)] was determined by the following formula.

(Equation 4)
SV (meq / g) = {(Vb−Vs) × f ₂ × (1/2)} / W
Next, the esterification rate (%) was determined from the AV (meq / g) and SV (meq / g) obtained above by the following formula.
(Equation 5)
Esterification rate (%) = {(SV-AV) / SV} × 100

<Cyclic trimer content (CT)>
10 g of a resin sample (part A of the molded plate shown in FIG. 1 when measuring the molded plate) is 160 ° C. in an inert oven (“IPHH-201 type” manufactured by ESPEC) under a nitrogen gas flow of 50 L / min. After being dried for 2 hours, 4.0 mg was precisely weighed and dissolved in 2 ml of a mixed solvent of chloroform / hexafluoroisopropanol (volume ratio 3/2), and further diluted with 20 ml of chloroform. 10 ml was added to cause precipitation. Subsequently, the filtrate obtained by filtering the resulting mixture was evaporated to dryness and then dissolved in 25 ml of dimethylformamide, and the amount of cyclic trimer (cyclotriethylene terephthalate) in the solution was measured by liquid chromatography (manufactured by Shimadzu Corporation). "LC-10A").

[Production Example 1]
Production of <Polyester Resin (A) -1> A slurry preparation tank, a two-stage esterification reaction tank connected in series to the slurry preparation tank, and a three-stage melt weight connected in series to the second-stage esterification reaction tank A continuous polymerization apparatus consisting of a condensation tank was used. Polyethylene terephthalate resin (polyester resin) is obtained by continuously feeding terephthalic acid and ethylene glycol to a slurry preparation tank at 865 parts by weight and 485 parts by weight, respectively, and a 0.3% by weight ethylene glycol solution of ethyl acid phosphate. (A) Equivalent) A raw material slurry was prepared by continuously adding in an amount such that the content PA as phosphorus atoms per ton was 0.113 mol / ton of resin, and stirring and mixing. This slurry was subjected to a first stage esterification reaction tank set at 260 ° C. under a nitrogen atmosphere, a relative pressure of 50 kPa (0.5 kg / cm ² G), and an average residence time of 4 hours, and then 260 ° C. under a nitrogen atmosphere. The mixture was continuously transferred to a second stage esterification reaction tank set at 0 ° C., a relative pressure of 5 kPa (0.05 kg / cm ² G), and an average residence time of 1.5 hours, and subjected to an esterification reaction. At that time, a 0.6 wt% ethylene glycol solution of magnesium acetate tetrahydrate is obtained through an upper pipe provided in the second stage esterification reaction tank, and the resulting polyethylene terephthalate resin (corresponding to polyester resin (A)) ) The content of MA as magnesium atom per ton is continuously added at an amount of 0.144 mol / ton of resin, and ethylene glycol is passed through another upper pipe provided in the second stage esterification reaction tank. Was continuously added at 30 parts by weight per hour. At that time, the esterification rate of the esterification product measured by the above method was 85% in the first stage and 95% in the second stage.

Subsequently, when the esterification reaction product obtained above is continuously transferred to the melt polycondensation tank, tetra-n-butyl titanate is added to the esterification reaction product in the transfer pipe with a concentration of titanium atoms. Content of TA as titanium atoms per ton of polyethylene terephthalate resin (corresponding to polyester resin (A)) obtained as an ethylene glycol solution with 0.15% by weight and water concentration of 0.5% by weight is 0.073 mol. / The first stage melt polycondensation tank set at 270 ° C. and an absolute pressure of 2.6 kPa (20 Torr) while continuously adding in an amount of resin tons, then 278 ° C. and an absolute pressure of 0.5 kPa ( The second stage melt polycondensation tank set at 4 Torr), and then the third stage melt polycondensation tank set at 280 ° C. and absolute pressure 0.3 kPa (2 Torr) And continuously transferred, the intrinsic viscosity of the obtained resin ([eta _1]) is adjusted to melt polycondensation residence time in each polycondensation vessel such that a 0.58 dl / g, the bottom of the polycondensation tank A melt polycondensation resin was produced in the form of pellets (grain weight 25 ± 5 mg) by continuously drawing into strands from the outlet provided in the tube and cutting with a cutter while cooling with water.

Subsequently, the melt polycondensation resin pellets obtained above are crystallized by continuously supplying them into a stirring crystallizer maintained at about 160 ° C. in a nitrogen atmosphere so that the residence time is about 30 minutes. After that, it is continuously supplied to a tower-type solid phase polycondensation apparatus and stays at 215 ° C. under a nitrogen atmosphere so that the intrinsic viscosity ([η ₁ ]) of the obtained resin is about 0.76 dl / g. Polyethylene terephthalate resin (A) -1 was produced by adjusting the time for solid phase polycondensation.
About the obtained polyethylene terephthalate resin (A) -1, the content TA of titanium atoms (mol / ton of resin), the content of magnesium atoms MA (mol / ton of resin), and the content of phosphorus atoms PA (mol / resin) Ton), the intrinsic viscosity [η ₁ ] (dl / g), the amount of terminal carboxyl groups (equivalent / ton of resin), and the results are shown in Table 1.

[Production Example 2]
<Production of <Polyester Resin (A) -2 >> By setting the relative pressure in the first stage esterification reaction tank to 100 kPa (1.0 kg / cm ² G), the esterification rate in the first stage is 88%. The polyester resin (A) -2 was obtained in the same manner as in the polyester resin (A) -1 in Production Example 1 except that the esterification rate in the second stage was 97%. Analysis was conducted in the same manner as for the polyester resin (A) -1, and the results are shown in Table 1.

[Production Example 3]
Production of <Polyester Resin (A) -3> Production of Catalyst Weighed 500 ml of deionized water in a 1000 ml glass beaker, cooled in an ice bath, and then dropped 5 g of titanium tetrachloride with stirring. When the generation of hydrogen chloride ceased, it was removed from the ice bath, and 25% aqueous ammonia was added dropwise with stirring to adjust the pH of the solution to 8. The produced titanium hydroxide precipitate was separated from the supernatant by centrifugation at 2500 rpm for 15 minutes. Thereafter, the resulting titanium hydroxide precipitate was washed five times with deionized water. Solid-liquid separation after washing was performed by centrifugation at 2500 rpm for 15 minutes. The washed titanium hydroxide was dried under reduced pressure at 70 ° C. and 1.3 kPa (10 Torr) for 18 hours to obtain a solid titanium compound. The obtained solid titanium compound was pulverized into particles of about 10 microns before use with a polycondensation catalyst.

  The amount of water adhering to the solid titanium compound thus obtained was measured with a Karl Fischer moisture meter and found to contain 6.7% by weight of water. In addition, when the weight loss by heating was measured by thermogravimetry, the weight decreased to 7.50% by weight of the initial weight by 280 ° C. and further 2.17% by weight from 280 ° C. to 600 ° C. It was found to be due to desorption. Nitrogen contained in the catalyst was 1.3% by weight and chlorine was 14 ppm. Nitrogen was analyzed by a trace total nitrogen analyzer (chemiluminescence method), and chlorine was analyzed by chromatography and calculated as desorbed as ammonia and hydrogen chloride, respectively.

Manufacture of resin A slurry prepared by mixing 6458 parts by weight / hour of high-purity terephthalic acid and 2909 parts by weight of ethylene glycol in a reactor in which 33500 parts by weight of the reaction liquid stays during steady operation. The esterification reaction was carried out under the conditions of 260 ° C. and 0.9 kg / cm ² G in a nitrogen atmosphere with stirring. Further, in the esterification reaction, 0.187 parts by weight / hour of the solid titanium compound as the catalyst prepared as described above is 0.187 parts by weight / hour and magnesium acetate is the magnesium atom. Supplied in proportion. In this esterification reaction, a mixed solution of water and ethylene glycol was distilled off.
The esterification reaction product (low-order condensate) was continuously extracted from the system while controlling the average residence time to be 3.5 hours. The number average molecular weight of the low-order condensate of ethylene glycol and terephthalic acid obtained above was 600 to 1300 (3 to 5 mer).

Subsequently, a liquid phase polycondensation reaction was performed under the conditions of 280 ° C. and 1 Torr while supplying 0.831 parts by weight of tributyl phosphate / hour into the low-order condensate. The intrinsic viscosity (IV) of the obtained polyethylene terephthalate resin was 0.55 dl / g.
Further, the polyethylene terephthalate resin obtained by this liquid phase polycondensation was crystallized at about 170 ° C. for 2 hours in a nitrogen atmosphere, and then charged into a tower-type solid phase polymerization machine, and at 210 ° C. in a nitrogen atmosphere. Solid state polymerization was performed for 25 hours. The obtained polyester resin (A) -3 was analyzed in the same manner as the polyester resin (A) -1 in Production Example 1 and the results are shown in Table 1.

[Example 1]
Put 2.5 kg of polyester resin (A) -1 obtained in Production Example 1 into a treatment tank with an internal volume of 5 L, and add 2.0 L of 5 wt% ethyl acid phosphate (EAP) aqueous solution (3200 wt ppm as phosphorus atom). Then, after contact treatment at 25 ° C. for 4 hours, filtration and water washing were performed, and drying was performed at 160 ° C. for 4 hours under a nitrogen stream to produce a polyester resin (B) -1.
About the obtained polyester resin (B) -1, content T of titanium atoms (mol / ton of resin), content of magnesium atoms M (mol / ton of resin), and content P of phosphorus atoms (mol / ton of resin) ) And P / (T + M) was calculated from the results, and the results are shown in Table 1. Further, with respect to the obtained polyester resin (B) -1, the intrinsic viscosity [η ₂ ] (dl / g), the terminal carboxyl group amount (equivalent / ton of resin), and the cyclic trimer content [CT ₀ ] were measured. The results are shown in Table 2-1.

Further, the obtained polyester resin (B) -1 was dried in an inert oven (“IPHH-201 type” manufactured by ESPEC) at 160 ° C. for 4 hours under a dry air stream of 40 L / min, and then injected. It is put into a hopper under a nitrogen stream of a molding machine (“M-70AII-DM”), cylinder temperature is 290 ° C., back pressure is 0.5 MPa, injection rate is 40 cc / sec in terms of polypropylene, holding pressure is 3.5 MPa, mold cooling water Injection molding was performed at a temperature of 21 ° C., an injection time of 25 seconds, a cooling time of 40 seconds, and a molding cycle of 73 seconds. The shape shown in FIG. 1 was 50 mm long, 100 mm wide, and 6 mm to 3.5 mm horizontally. A stepped molded plate (50 g) having a thickness of 6 steps with a step of 0.5 mm was obtained. (In FIG. 1, G is a gate portion.)
The intrinsic viscosity [η ₃ ] (dl / g) and cyclic trimer content [CT ₁ ] (% by weight) of the obtained stepped molded plate were measured, and the intrinsic viscosity retention [η ₃ ] / [η ₂ ] and the increase amount [CT ₁ ]-[CT ₀ ] of the cyclic trimer were calculated, and the results are shown in Table 2-1.

[Examples 2 to 6]
The polyester resin (B) -2 to (-) was operated in the same manner as in Example 1 except that the contact conditions of the polyester resin (A) -1 and the phosphorus compound in Example 1 were those described in Table 2-1. B) -6 was produced. Each resin obtained was subjected to molding evaluation and analysis in the same manner as in Example 1, and the results are shown in Table 2-1.

[Example 7]
A polyester resin (B) -7 was produced in the same manner as in Example 2 except that the polyester resin (A) -2 was used in Example 2. The obtained resin was subjected to molding evaluation in the same manner as in Example 2 and analyzed. The results are shown in Table 2-1.

[Comparative Example 1]
As a phosphorus compound solution to be brought into contact with the polyester resin (A) -1 in Example 1, 2.0 L of 1.0 wt% phosphoric acid aqueous solution (3200 wt ppm as phosphorus atom) is added, and contact treatment is performed at 25 ° C. for 4 hours. A polyester resin (B) -11 was produced in the same manner as in Example 1 except that. The obtained resin was subjected to molding evaluation in the same manner as in Example 1 and analyzed. The results are shown in Table 2-2.

[Comparative Example 2]
As a phosphorus compound solution to be brought into contact with the polyester resin (A) -1 in Example 1, 2.0 L of 1.0 wt% phosphoric acid aqueous solution (3200 wt ppm as phosphorus atom) is added, and the mixture is heated at 90 ° C. for 0.5 hours. A polyester resin (B) -12 was produced in the same manner as in Example 1 except that the contact treatment was performed. The obtained resin was subjected to molding evaluation in the same manner as in Example 1 and analyzed. The results are shown in Table 2.

[Comparative Example 3]
As a phosphorus compound solution to be brought into contact with the polyester resin (A) -1 in Example 1, 2.0 L of an aqueous solution of 1.5 wt% trimethyl phosphate (TMP) (3200 ppm by weight as phosphorus atom) was added at 25 ° C. A polyester resin (B) -13 was produced in the same manner as in Example 1 except that the contact treatment was performed for 4 hours. The obtained resin was subjected to molding evaluation in the same manner as in Example 1 and analyzed. The results are shown in Table 2-2.

[Comparative Example 4]
As a phosphorus compound solution to be brought into contact with the polyester resin (A) -1 in Example 1, 2.0 L of a 30 wt% aqueous solution of trimethyl phosphate (66000 ppm by weight as phosphorus atom) is added and contact-treated at 100 ° C. for 1 hour. Except that, polyester resin (B) -14 was produced in the same manner as in Example 1. The obtained resin was remarkably reduced in intrinsic viscosity and could not be evaluated for injection molding. The analysis was performed in the same manner as in Example 1. The results are shown in Table 2-2.

[Comparative Example 5]
In Example 1, 0.0695 wt% trimethyl phosphate aqueous solution (150 ppm by weight as phosphorus atom) 2.0 L as a phosphorus compound solution to be brought into contact with polyester resin (A) -3 using polyester resin (A) -3 Was added and the polyester resin (B) -15 was produced in the same manner as in Example 1 except that the contact treatment was performed at 25 ° C. for 4 hours. The obtained resin was subjected to molding evaluation in the same manner as in Example 1 and analyzed. The results are shown in Table 2-2.

[Comparative Example 6]
In Comparative Example 5, the polyester resin (B) -16 was treated in the same manner as in Comparative Example 5 except that the contact conditions of the polyester resin (A) -3 and the phosphorus compound solution were those shown in Table 2-2. Manufactured. The obtained resin was subjected to molding evaluation in the same manner as in Comparative Example 5 and analyzed. The results are shown in Table 2-2.

[Comparative Example 7]
Comparative Example 5 and Comparative Example 5 except that 2.0 L of an aqueous solution of 1.5 wt% ethyl acid phosphate (3200 wt ppm as phosphorus atoms) was added as the phosphorus compound solution to be brought into contact with the polyester resin (A) -3. In the same manner, a polyester resin (B) -17 was produced. The obtained resin was subjected to molding evaluation in the same manner as in Comparative Example 5 and analyzed. The results are shown in Table 2-2.

[Comparative Example 8]
The polyester resin (A) -1 was molded and evaluated in the same manner as in Example 1 without being brought into contact with the phosphorus compound solution, and analyzed. The results are shown in Table 2-2.

(A) is a plan view of a stepped molding plate formed by injection molding in molding evaluation, and (b) is a side view, which is 50 mm in length and 100 mm in width and 6 steps from 6 mm to 3.5 mm in the horizontal direction. Having a thickness of

Explanation of symbols

A. Annular trimer measurement sample part of molded plate B. Haze measurement sample part of molded plate G Gate part

Claims (10)

A polyester resin (A) produced using a titanium compound as a catalyst from a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component is contacted with a phosphorus compound, and obtained after contact. A method for producing a polyester resin, wherein the polyester resin (B) satisfies the following formulas (1) to (3).
(1) 0.002 ≦ T ≦ 0.2
(2) P / (T + X) ≧ 4.0
(3) X ≧ 0
In the formulas (1) to (3), T is the content of titanium atoms per ton of the polyester resin (B) (mol / ton of resin), and X is other than the titanium atoms per ton of the polyester resin (B). The content of metal atoms (mol / ton of resin) and P represent the content of phosphorus atoms per ton of polyester resin (B) (mol / ton of resin).   The method for producing a polyester resin according to claim 1, wherein the polyester resin (A) has a terminal carboxyl group amount of 20 equivalents / ton of resin or less. The polyester resin (A) is a polyester resin produced using a titanium compound catalyst, a magnesium compound, and a phosphorus compound, and satisfying the following formulas (4) to (8). Of manufacturing polyester resin.
(4) 0.020 ≦ TA ≦ 0.200
(5) 0.040 ≦ MA ≦ 0.400
(6) 0.020 ≦ PA ≦ 0.300
(7) 0.50 ≦ MA / PA ≦ 3.00
(8) 0.20 ≦ MA / TA ≦ 4.00
However, in the formulas (4) to (8), TA is the content of titanium atoms per ton of the polyester resin (A) (mol / ton of resin), and MA is the contents of magnesium atoms per ton of the polyester resin (A). The amount (mol / ton of resin) and PA represent the content (mol / ton of resin) of phosphorus atoms per ton of the polyester resin (A).   The method for producing a polyester resin according to any one of claims 1 to 3, wherein the phosphorus compound brought into contact with the polyester resin (A) is an acidic phosphate or a solution thereof. Polyester obtained by bringing a polyester resin (A) produced using a titanium compound as a catalyst from a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component into contact with a phosphorus compound A polyester resin which is a resin (B) and satisfies the following formulas (1) to (3).
(1) 0.002 ≦ T ≦ 0.2
(2) P / (T + X) ≧ 4.0
(3) X ≧ 0
In the formulas (1) to (3), T is the content of titanium atoms per ton of the polyester resin (B) (mol / ton of resin), and X is other than the titanium atoms per ton of the polyester resin (B). The content of metal atoms (mol / ton of resin) and P represent the content of phosphorus atoms per ton of polyester resin (B) (mol / ton of resin).   6. The polyester resin according to claim 5, wherein the polyester resin (B) has a terminal carboxyl group amount of 20 equivalents / ton of resin or less. The polyester resin (B) is obtained by bringing a polyester resin (A) produced using a titanium compound catalyst and a magnesium compound into contact with a phosphorus compound, and satisfies the following formulas (9) to (11): The polyester resin in any one of Claims 5-6.
(9) 0.040 ≦ M ≦ 0.400
(10) 1.00 ≦ P ≦ 6.50
(11) 0.20 ≦ M / T ≦ 4.00
In the formulas (9) to (11), M is the content of magnesium atoms per ton of the polyester resin (B) (mol / ton of resin), and P is the content of phosphorus atoms per ton of the polyester resin (B). The amount (mol / ton of resin) and T represent the content (mol / ton of resin) of titanium atoms per ton of the polyester resin (B).   The polyester resin (B) has an intrinsic viscosity of 0.50 to 1.50 dl / g, a cyclic trimer content of 0.5% by weight or less, and a molded product obtained by molding at 290 ° C. The polyester resin according to any one of claims 5 to 7, wherein the cyclic trimer increase amount is 0.05 wt% or less.   9. The polyester resin according to claim 5, wherein the polyester resin (B) has an inherent viscosity retention of 94% or more when injection molded at 290 ° C. 9.   The polyester resin according to any one of claims 5 to 9, wherein the polyester resin (B) is used for injection molding or injection blow molding.

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