JPS6139969B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a method for producing polyester using terephthalic acid and ethylene glycol as main raw materials,
More specifically, the present invention relates to fibers having good glitter and transparency, and excellent stretchability. Bis-β-hydroxyethyl terephthalate and/or its low polymer (hereinafter referred to as EG) is produced from terephthalic acid (hereinafter referred to as TPA) and ethylene glycol (hereinafter referred to as EG) through an esterification reaction.
Polyethylene terephthalate (hereinafter referred to as BHT) is produced by polycondensing it.
Due to its excellent properties, PET has many uses, especially in clothing fibers. However, since it is impossible to add, for example, titanium dioxide as a lubricant to bright fibers that take full advantage of their glitter and transparency, the mass coefficient between the fibers and the metal during drawing increases, resulting in poor silk-spinning operation. becomes defective. As a method to improve this drawback, one or more types of organic carboxylic acids of various metals such as sodium acetate or calcium acetate or hydrides such as lithium hydride or calcium hydride are present during the esterification or transesterification reaction. A method of polycondensation by adding a phosphorus compound such as phosphoric acid in an amount equivalent to or more than the metal compound after carrying out a transesterification or transesterification reaction (Tokuko Showa)
49-13234). However, when polyester is produced by this method, coarse particles and coarse foreign matter are generated in the BHT and mixed into the polymer, and the amount of particles generated in the polymer (so-called internal particle amount) is not constant, resulting in yarn production. It was found that the operability was markedly poor. In addition, as a method for producing particles in the polymer, the esterification reaction rate is 91 to 97.5% (preferably 92.5%).
For polymers that produce alkylene glycol soluble carboxylic acid calcium salts within the range of ~95%)
Add 0.03 to 0.3% by weight to increase Ca/P molar ratio from 1.0 to
A method of setting the range to 10.0 is also known. (Tokukai Akira
50-6493) However, even with this method, if the esterification reaction rate is 91% or more and less than 95%, coarse particles will be generated in the polymer and the amount of particles in the polymer will fluctuate greatly. It was found that the amount of particles in the produced polymer was insufficient when the esterification reaction rate was in the range of 95 to 97.5%. On the other hand, a method is also known in which an EG solution of an alkaline earth metal salt of TPA and/or BHT is added during the polyester manufacturing process (Japanese Patent Publication No. 47-19866
Publication No. 49-5634, Publication No. 49-5914, etc.), but because the metal salt has a low solubility in EG, it is difficult to prepare an EG solution, and coarse foreign matter may be mixed into the polymer. It was found that the silk reeling operability was markedly poor. In order to overcome these drawbacks, the inventors of the present invention have conducted intensive studies on a method for producing polyester bright yarn with excellent spinning operability, and as a result, they have arrived at the present invention. That is, the present invention involves reacting a dicarboxylic acid mainly composed of TPA with a content of 4-carboxybenzaldehyde (hereinafter referred to as FBA) of 250 ppm or less and a glycol mainly composed of EG until the esterification reaction rate reaches 95% or more. This is a method for producing polyester, which comprises adding a calcium compound, a manganese compound, and a phosphorus compound satisfying the following formulas (1) to (4). 70≦Ca≦250 (1) 3≦Mn≦45 (2) 10≦P≦60 (3) 0≦P−0.56Mn≦50 (4) (Ca, Mn, and P are the amounts of added atoms [ppm vs. polymer ]
shows. ) The method of esterification reaction in the present invention is as follows:
Although any method may be used, the method described below is most preferred from the viewpoint of the diethylene glycol (hereinafter referred to as DEG) content in the polymer. That is, it is a method in which a slurry consisting of a dicarboxylic acid and glycol is continuously or intermittently supplied to a system in which BHT is present in an amount of 50 to 150% by weight relative to the dicarboxylic acid mainly composed of TPA to be added, to effect esterification. be. The BHT may partially contain components other than TPA residues and EG groups. Further, as this BHT, one obtained by any method may be used, but it is preferable to use the above-mentioned esterification reaction product as it is. Of course, the TPA and EG slurry used in the present invention contains other acid components (isophthalic acid, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, etc.) and glycol components (tetramethylene glycol, neopentyl glycol, -4-cyclohexanedimethanol, etc.) may be contained in a small amount. The molar ratio of this EG/TPA slurry is preferably 1.05 to 1.5, particularly preferably 1.10 to 1.25. Further, the esterification reaction may be carried out under normal pressure or under increased pressure, but a gauge pressure of 0.8 Kg/cm ² or less is preferred, and a gauge pressure of 0.45 Kg/cm ² or less is most preferred. That is, if the reaction is carried out under pressure, the esterification reaction time is generally shortened, but if the gauge pressure is higher than 0.8 Kg/cm ² , it is not preferable because it promotes the DEG by-product reaction during the esterification reaction. The reaction temperature for esterification is preferably 200-260°C, most preferably 220-250°C. If the reaction temperature is less than 200℃, the esterification reaction time will be longer, and if it exceeds 260℃, the esterification reaction time will be longer.
This is not preferred because DEG increases and the resulting product becomes colored. Here, the TPA used needs to have an FBA content of 250 ppm or less, more preferably 100 ppm or less, from the viewpoint of polymer color tone and yarn color tone. i.e. contains more than 250ppm FBA
If TPA is used, the color tone of the polymer and the color tone of the yarn will become strongly yellowish when a manganese compound is added, which is not preferable. In this way, a calcium compound, a manganese compound, which satisfies formulas (1) to (4) to the esterified BHT with a reaction rate of 95% or more (more preferably a reaction rate of more than 97.5% and less than 99%), The object of the present invention can be achieved by adding a phosphorus compound and immediately carrying out polycondensation thereafter. At this time, by passing the BHT with a reaction rate of 95% or more through a filter installed between the esterification can and the polymerization can, and then immediately adding the above compound to the BHT, foreign substances in TPA can be separated by the filter. It is more preferable in this respect. If these compounds are added before the esterification reaction rate has reached 95%, coarse particles or coarse foreign matter may be produced, or the amount of particles in the resulting polymer will vary greatly, making it difficult to control the amount of particles.
In addition, BHT whose esterification reaction rate does not reach 95%
When transferring to the next reaction tank (polymerization tank), put it in the filter installed between the esterification tank and the polymerization tank.
Problems such as TPA becoming clogged and becoming unusable occur. On the other hand, it was also found that even if the esterification reaction rate was 95% or more, it was not possible to obtain sufficient color tone, gloss, and particle amount for bright yarns using only calcium compounds and phosphorus compounds. The present inventors have discovered that by adding a specific amount of a manganese compound, these problems can be completely resolved and a polymer having the color tone, gloss, and particle amount suitable for bright yarns can be obtained. These calcium compounds and manganese compounds are preferably added as a glycol (preferably EG) solution or slurry, and more preferably as a solution. In addition, the amount of glycol in the solution or slurry is 2 to 7% by weight based on the polymer.
It is preferable that these compounds are added simultaneously in an EG solution. The amounts of these calcium compounds and manganese compounds added must satisfy formulas (1) to (4), and the more preferable amounts are formula (5) for calcium compounds and formula (6) for manganese compounds. , is the amount added that satisfies equation (7). 90≦Ca≦220 (5) 5≦Mn≦35 (6) 0≦P−0.56Mn≦45 (7) When the calcium compound is less than 70ppm as Ca atoms or more than 50ppm (P−0.56Mn), the polymer The color tone is poor and the amount of particles is insufficient. Also, calcium compounds as Ca atoms
More than 250ppm (P-0.56Mn) is 0ppm
If it is less than this, the color tone of the polymer will be poor, the heat resistance of the polymer will be poor, and coarse particles will also be formed in the polymer, which is not preferable. The amount of manganese compound added is expressed as Mn atoms.
If it is less than 3ppm, the effect of increasing the particle amount is insufficient;
On the other hand, if the amount is more than 45 ppm, the effect of increasing the particle amount does not change so much, and the color tone of the polymer becomes yellowish, and the heat resistance of the polymer decreases, which is not preferable. Furthermore, when adding the polycondensation catalyst, it is preferable to add it in the form of a solution or slurry of glycol (preferably EG) at the same time as the calcium compound and the manganese compound. Examples of polycondensation catalysts include antimony compounds and titanium compounds, but antimony compounds, particularly antimony trioxide, are preferred. If the amount of this antimony compound added is too large, the polymer color tone will be poor and the heat resistance will be poor, while if it is too small, the polymerization activity will be insufficient, so the amount added should be 167ppm≦Sb≦300 as Sb atoms. is preferred. It is preferable to immediately add a small amount of glycol to clean the addition line after adding these metal compounds. Further, the timing of addition of the phosphorus compound is preferably 5 to 20 minutes after addition of the calcium compound in terms of the amount of particles in the polymer and the color tone of the polymer. The addition of this phosphorus compound is a calcium compound,
It is preferable to add the manganese compound and the polycondensation catalyst separately from the addition port, and it is most preferable to fill and add the phosphorus compound into a container having an opening mainly made of PET. At that time, the phosphorus compound may be diluted with ethylene glycol and added. The phosphorus compound may be added through the same port as these metal compounds, but it is preferable to add the phosphorus compound separately from the viewpoint of preventing metal foreign matter from forming in the addition port due to reaction with the metal and clogging the addition port. The amount of the phosphorus compound added must satisfy formulas (3) and (4), and is more preferably 10 ppm or more and 50 ppm or less in terms of phosphorus atoms. If the phosphorus compound is less than 10 ppm in terms of phosphorus atoms, the color tone of the polymer will be poor and the heat resistance of the polymer will also be poor.
Moreover, if it exceeds 60 ppm, the amount of particles in the polymer decreases, which is not preferable. Examples of the calcium compound include calcium acetate and calcium chloride, with calcium acetate being the most preferred. Manganese compounds include manganese acetate and manganese chloride, but manganese acetate is most preferred. Phosphorus compounds include phosphoric acid, partial esters of phosphoric acid, esters of phosphoric acid, phosphorous acid, and esters of phosphorous acid, but from the viewpoint of polymer whiteness, phosphoric acid, partial methyl esters of phosphoric acid, and trimethyl phosphoric acid are used. Eates are preferred, especially phosphoric acid. In addition, polyester coloring inhibitors and other various additives used during the production of polyester can also be added within the range that does not impair the purpose of the present invention. As described above, according to the present invention, it is possible to produce bright yarn with good yarn spinning operability. The present invention will be explained in detail with reference to Examples below. In addition, parts in Examples are parts by weight, and the measurement method of each characteristic is as follows. [Polymer color tone] Measured in chip form using a direct color difference meter (Suga Test Instruments Co., Ltd.) and expressed as b value (Hunter value). [Solution haze] Precisely weigh 2.7 g of polymer, add 20 c.c. of a mixed solvent of phenol/tetrachloroethane (6/4 weight ratio), and stir at 102° C. for 2 hours to dissolve the polymer. The polymer solution is left to cool at room temperature for 1 hour. This sample was placed in a 10 mm quartz cell, and an integrating sphere type H ₁ T ₁ R ₁ METER SEP− manufactured by Nippon Seimitsu Kogaku Co., Ltd.
ASTM-1003-62 using H-type haze meter
Measure the solution haze and use it as a guideline for the amount of particles in the polymer. [%BB] Used as a method for evaluating heat resistance of polymers. Place the polymer in a test tube and vacuum dry at 140℃ for 12 hours. After placing this sample in a 300°C bath and treating it under nitrogen for 10 minutes for 8 hours, the intrinsic viscosity of this polymer was measured and %BB was determined according to equation (9). %BB=0.27 [[η] ^-4/3 ₈ hours - [η] ^-4/3 _1
0 minutes] (9) [Particle size] Place 2 mg of chips in a preparation on a plate heated to 270°C and melt-press. The size of the internal particles is observed using a microscope with a 10x eyepiece and a 10x objective inserted into the light-shielding plate, and the size of the internal particles is determined by the size: Fine: A: Slightly coarse: B: Coarse: C Extremely rough: Classified as D. Example 1 Esterification reaction rate of 97.3% with TPA and EG with FBA content below the detection limit of 15 ppm

[Formula] 1760 parts of BHT with a unit molar ratio of 1.20 (122 parts for added TPA)
% by weight) was stored in a reactor at 240℃ and processed into FBA at normal pressure.
1441 parts of TPA with a content below the detection limit of 15ppm
A slurry of 646 parts of EG (EG/TPA molar ratio 1.20) was continuously fed at a constant rate over a period of 4 hours and 15 minutes. While supplying the slurry, the temperature is controlled at 230 to 245°C, and after the slurry supply is completed, the temperature is controlled at 240 to 250°C to achieve an esterification reaction rate of 98.1%. 1760 parts of this BHT was passed through a 200 mesh wire mesh filter, transferred to a polymerization can, and polycondensed as follows. Namely, 0.075% by weight of calcium acetate/half hydrate vs. PET (180 ppm as calcium atoms), 0.01% by weight of manganese acetate/tetrahydrate vs. PET (22 ppm as manganese atoms), 0.03% by weight of antimony trioxide vs. PET (antimony 85% phosphoric acid, 0.01 ppm) filled into a PET-based container with an opening (PET bottle) 15 minutes after addition of a solution of EG (5 wt.% vs. PET) containing 251 ppm (as atoms).
The weight percent of PET (27 ppm as phosphorus atoms) was added through a separate port from the metal compound addition port. Immediately, polycondensation was carried out under reduced pressure (by lowering the degree of vacuum to 1 mmHg or less in 60 minutes and simultaneously increasing the temperature to 288°C) to reach an intrinsic viscosity of 0.66 in 4 hours and 16 minutes. The polymer quality was a b value of +4.4, the particle size in the chips was extremely fine, and the solution haze was 20.1%. Example 2 After esterification in exactly the same manner as in Example 1
BHT (esterification reaction rate 98.1%) passed through a 200-mesh wire mesh filter and transferred to a polymerization tank, and 0.02 to 0.105% by weight of calcium acetate and 1/2 hydrate were added to PET.
(47-252 ppm as calcium atoms), 0-0.025% by weight of manganese acetate tetrahydrate vs. PET (0-55 ppm as manganese atoms), 0.03 antimony trioxide
Weight% vs. PET (as antimony atoms)
251ppm), 85% phosphoric acid 0-0.025% by weight vs. PET
(0 to 67 ppm as phosphorus atoms) was added in the same manner as in Example 1, and then polycondensed. Table 1 shows the polymer quality. It can be seen that if the amount of phosphorus added is less than 10 ppm (No. 12), the particle size is coarse and the heat resistance is poor, and if it is more than 60 ppm (No. 15), the particle amount is small. It can be seen that when the amount of manganese added is less than 0 to 3 ppm, the color tone of the polymer is poor, the amount of particles is small, and the size of the particles becomes coarse (Nos. 1, 2, and 8).
In addition, if the amount of calcium added is less than 70 ppm, the polymer color tone is poor and the particle amount is small (No. 3).
It can be seen that when the amount exceeds 250 ppm, the heat resistance of the polymer becomes poor and the particle size becomes coarse (No. 7). On the other hand, even if the amount of phosphorus added is 10 ppm or more and 60 ppm or less, if (P-0.56Mn) is less than 0 ppm, the polymer color tone, polymer heat resistance will be poor, and the particle size will become coarse (No. 11). (P-
0.56Mn) is more than 50 ppm, the polymer color tone is poor and the particle amount is also small (No. 5). From the above, it can be seen that only Nos. 4, 6, 9, 10, 13, and 14 can achieve the object of the present invention.

[Table] Example 3 BHT esterified in exactly the same manner as Example 1
0.075% by weight of calcium acetate/half hydrate vs. PET (180 ppm as calcium atoms), 0.01% by weight of manganese acetate/tetrahydrate vs. PET (manganese atoms) as 22ppm) and antimony trioxide 0.03
Weight% vs. PET (251ppm as antimony atoms)
85% phosphoric acid 0.01 wt% to PET (27 ppm as phosphorus atoms) was added 1 to 25 minutes after addition of a solution of EG (5% to PET) containing 85% phosphoric acid, followed by polycondensation as in Example 1. I forced it. Polymer quality is shown in Table 2. As is clear from Table 2, it can be seen that when the addition interval of calcium acetate and phosphoric acid is set to 5 to 20 minutes, the polymer color tone and particle size become even better.

[Table] Example 4 Esterification reaction rate 85% as in Example 1
~98.7% BHT was obtained, 1/2 of this BHT was transferred to the next reaction layer (polymerization can) through a 200 mesh wire mesh filter, and calcium acetate 1/2 hydrate was added using the same catalyst addition method as in Example 1. (as a calcium atom
180ppm), manganese acetate tetrahydrate (22ppm as manganese atoms), 85% phosphoric acid (as phosphorus atoms)
27ppm) was added. Polymer quality is shown in Table 3.

[Table] From Table 3, when the esterification reaction rate of BHT is less than 95%, the haze increases by 9 if the esterification reaction rate changes by 4%.
It can be seen that the change is about ~10%, but at 95% or more, the change is only about 3%. Therefore, it can be seen that when the esterification reaction rate is 95% or more, the change in haze when the esterification reaction rate changes is small. Furthermore, it can be seen that when the ratio is less than 95%, the particle size is also coarse. Example 5 BHT was esterified in exactly the same manner as in Example 1 using various TPAs with different FBA contents in TPA.
1/2 of the amount was transferred to a polymerization vessel and polycondensed using the same catalyst formulation and polymerization conditions as in Example 1. Polymer quality is shown in Table 4. It can be seen that when the FBA content is less than 250 ppm, the chip color tone is good (particularly less than 100 ppm), but when it is more than 250 ppm, it is poor.

【table】

Claims (1)

[Claims] 1 The content of 4-carboxybenzaldehyde is
Calcium that satisfies the following formulas (1) to (4) is produced by reacting a dicarboxylic acid mainly composed of terephthalic acid of 250 ppm or less with a glycol mainly composed of ethylene glycol until the esterification reaction rate reaches 95% or more. 1. A method for producing polyester, which comprises adding a manganese compound and a phosphorus compound. 70≦Ca≦250 (1) 3≦Mn≦45 (2) 10≦P≦60 (3) 0≦P−0.56Mn≦50 (4) (Ca, Mn, and P are the amounts of added atoms [ppm vs. polymer ]
shows. )