JP3911114B2 - Method for producing polybutylene terephthalate resin and polybutylene terephthalate resin obtained thereby - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polybutylene terephthalate resin and a polybutylene terephthalate resin obtained thereby, and more particularly, a polybutylene terephthalate resin that undergoes an esterification reaction in the presence of an esterification catalyst of a titanium compound. In the production method, a method for producing a polybutylene terephthalate-based resin with less fish eyes and a polybutylene terephthalate-based resin obtained thereby.
[0002]
[Prior art]
Polybutylene terephthalate resin has higher crystallization speed and superior molding processability than polyethylene terephthalate resin, and also has excellent mechanical and electrical properties. In recent years, the properties of the polybutylene terephthalate resin, such as fragrance retention and chemical resistance, have been recognized and have attracted attention in the field of film formation.
[0003]
By the way, a method for producing a polybutylene terephthalate resin is a transesterification reaction between a dicarboxylic acid ester component mainly composed of an ester derivative of terephthalic acid such as dimethyl terephthalate and a diol component mainly composed of 1,4-butanediol. And a method of undergoing an esterification reaction between a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component. A method through the latter esterification reaction is advantageous.
[0004]
However, in the method through this esterification reaction, 1,4-butanediol undergoes a self-cyclization reaction in the presence of terephthalic acid to suppress the side reaction that becomes tetrahydrofuran, and the esterification reaction that is a positive reaction is also performed. In order to promote, it is essential to use an esterification reaction catalyst. When a titanium compound is used as the esterification reaction catalyst, a part of the titanium compound is precipitated by water produced as a by-product in the esterification reaction to generate an aggregate, and the aggregate is a fish eye in a film as a molded body. Is a method that undergoes an esterification reaction in the presence of a catalyst for esterification of a titanium compound. Has been an obstacle to advance into the field of film formation of polybutylene terephthalate resin.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described prior art. Accordingly, the present invention provides a method for producing a polybutylene terephthalate resin that undergoes an esterification reaction in the presence of an esterification reaction catalyst of a titanium compound. It is an object of the present invention to provide a method for producing a polybutylene terephthalate resin having a low content and a polybutylene terephthalate resin obtained thereby.
[0006]
[Means for Solving the Problems]
  The present invention has been made to achieve the above object, that is, the present invention comprises a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of 1,4-butanediol. In one or more esterification reaction tanks, the esterification reaction is carried out in the presence of an esterification reaction catalyst of 30 to 300 ppm of titanium compound as titanium atoms relative to the theoretical yield of the resin, and then one or more polycondensation reaction tanks In the production of a polybutylene terephthalate resin by performing a polycondensation reaction in the interior of the polymer extraction die, a filter is provided in the reaction product flow path between the outlet of the first esterification reaction tank and the outlet of the polymer extraction die. And a method for producing a polybutylene terephthalate resin in which the reaction product is passed through the filter, andTheRib Tylene terephthalate resin, 10 fish eyes having a nucleus of 20 μm or more in the film of the resin / 100 cm²Requires the following polybutylene terephthalate resin
Let ’s do it.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the method for producing a polybutylene terephthalate resin of the present invention, a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component are present in the presence of an esterification catalyst for a titanium compound. The polybutylene terephthalate resin is produced by conducting an esterification reaction, followed by a polycondensation reaction and then extracting from a polymer extraction die.
[0008]
Here, terephthalic acid as the dicarboxylic acid component accounts for 50 mol% or more of the total dicarboxylic acid component, preferably 80 mol% or more, and more preferably 95 mol% or more. Further, 1,4-butanediol as the diol component accounts for 50 mol% or more of the total diol component, preferably 80 mol% or more, and more preferably 95 mol% or more.
[0009]
In the present invention, specific examples of the dicarboxylic acid component other than terephthalic acid include, for example, phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4,4′- Aromatic dicarboxylic acids such as diphenyl ketone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1, Alicyclic dicarboxylic acids such as 3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid Etc.
[0010]
Specific examples of diol components other than 1,4-butanediol include, for example, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, 1,3-propanediol, polytetramethylene ether glycol, 1,5- Aliphatic diols such as pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1, Aromatic diols such as 4-cyclohexane dimethylol, aromatics such as xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone Diol etc. It is below.
[0011]
Furthermore, for example, hydroxycarboxylic acids such as glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, p-β-hydroxyethoxybenzoic acid, alkoxycarboxylic acids, and stearyl. Monofunctional components such as alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylol One or two or more multifunctional components such as propane, glycerol and pentaerythritol may be used as the copolymer component.
[0012]
The production method of the polybutylene terephthalate resin of the present invention is basically based on a conventional production method of a polybutylene terephthalate resin. That is, the dicarboxylic acid component containing terephthalic acid as the main component and the diol component containing 1,4-butanediol as the main component in one or a plurality of esterification reaction vessels in the presence of an esterification reaction catalyst. The esterification reaction is usually performed at a temperature of 150 to 280 ° C., preferably 180 to 265 ° C., usually 6.7 to 133 kPa, preferably 9.3 to 101 kPa, with stirring for 2 to 5 hours. The oligomer as the esterification reaction product is transferred to a polycondensation reaction tank and is usually 210 to 280 ° C., preferably 220 to 265 ° C. in the presence of a polycondensation reaction catalyst in one or a plurality of polycondensation reaction tanks. The polycondensation reaction is carried out for 2 to 5 hours under stirring at a reduced pressure of usually 27 kPa or less, preferably 20 kPa or less. These are continuous, semi-continuous, or It may be any of a batch system. In addition, the resin obtained by the polycondensation reaction is usually transferred from the bottom of the polycondensation reaction tank to a polymer extraction die and extracted into a strand shape, while being cooled with water or after water cooling, and then cut into a pellet, It is a granular material such as a chip.
[0013]
  Here, it is essential to use at least a titanium compound as the esterification reaction catalyst in the present invention. Examples of the titanium compound include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, and tetraphenyl titanate. Typical examples include titanium phenolate, and the amount used isTheAs a titanium atom for the theoretical yield of ribylene terephthalate resin30 to 300 ppm, preferably 50 to 200 ppm.
[0014]
In addition to the titanium compound, for example, a tin compound, a magnesium compound, a calcium compound, and the like can be used as the esterification reaction catalyst.
[0015]
In addition, as the polycondensation reaction catalyst, the esterification reaction catalyst added during the esterification reaction may be used as the polycondensation reaction catalyst, so that no new catalyst needs to be added. The same catalyst as the conversion reaction catalyst may be further added. In this case, the amount used is, for example, in the case of tetrabutyl titanate, usually 300 ppm or less, preferably as titanium atoms with respect to the theoretical yield of polybutylene terephthalate resin. 150 ppm or less, and different from the esterification reaction catalyst added during the esterification reaction, for example, an antimony compound such as antimony trioxide, a germanium compound such as germanium dioxide, germanium tetroxide, or the like may be newly added. .
[0016]
In the esterification reaction and / or polycondensation reaction, besides the catalyst, orthophosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, and phosphorus compounds such as esters and metal salts thereof, sodium hydroxide , Reaction aids such as alkali metal or alkaline earth metal compounds such as sodium benzoate, magnesium acetate and calcium acetate, 2,6-di-t-butyl-4-octylphenol, pentaerythrityl-tetrakis [3- (3 Phenol compounds such as', 5'-t-butyl-4'-hydroxyphenyl) propionate], dilauryl-3,3'-thiodipropionate, pentaerythrityl-tetrakis (3-laurylthiodipropionate), etc. Thioether compounds, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2,4-di Anti-oxidants such as phosphorous compounds such as t-butylphenyl) phosphite, paraffin wax, microcrystalline wax, polyethylene wax, long-chain fatty acids such as montanic acid and montanic acid ester and their release, release of silicone oil, etc. Other additives such as agents may be present.
[0017]
The esterification reaction tank may be of any type, for example, a vertical stirring complete mixing tank, a vertical heat convection mixing tank, a tower-type continuous reaction tank, etc. Alternatively, a plurality of tanks in which different tanks are connected in series may be used. Further, the polycondensation reaction tank may be of any type such as a vertical stirring polymerization tank, a horizontal stirring polymerization tank, a thin film evaporation type polymerization tank, and the like or different tanks as a single tank. It is good also as a plurality of tanks in series.
[0018]
In the present invention, in the method for producing a polybutylene terephthalate resin, a reaction product is formed by installing a filter in the reaction product flow path from the outlet of the first esterification reaction tank to the outlet of the polymer extraction die. Is required to pass through the filter.
Here, the filter refers to a fluid having a melt viscosity of several thousand poise that exits from the outlet of the polymer extraction die from a filter that can filter a fluid having a melt viscosity of several tens to 100 poise that exits from the outlet of the first transesterification reactor. Any known filter can be used as long as it can be filtered.
As a filter medium, for example, several fine meshes that determine filtration accuracy, reinforcing meshes and protective meshes are stacked, laminated metal meshes that are completely integrated by sintering, and stainless steel metal fiber felts, A sintered metal nonwoven fabric and the like can be mentioned.
[0019]
Examples of the shape of the filter include a basket type, a disk type, a leaf disk type, a tube type, a flat cylindrical type, and a pleated cylindrical type.
These filters can be appropriately selected and used according to the conditions such as the viscosity, pressure and temperature of the fluid at the installation location. However, when the oligomer having a low melt viscosity is installed at a location to be filtered, a viewpoint such as detergency Tube type or flat cylinder type is preferred, and when installing prepolymers or polymers with high melt viscosity at the location where the polymer is filtered, the leaf disk type or pleated cylinder is used in terms of pressure resistance and processing flow rate per unit area. Type is preferred.
The absolute filtration accuracy of these filters is preferably in the range of 0.5 to 50 μm from the viewpoint of filtration efficiency and the like. In the case of oligomer filtration with a low melt viscosity, the range of 0.5 to 30 μm In the case of filtration of a prepolymer having a high melt viscosity or a polymer, it is more preferably in the range of 5 to 50 μm.
[0020]
The production method of the polybutylene terephthalate resin of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a flowchart showing an embodiment of a production apparatus used for the production method of the polybutylene terephthalate resin of the present invention. In FIG. 1, 1 is a slurry preparation tank, 1a and 1b are raw material supply ports for a dicarboxylic acid component and a diol component provided at the top of the slurry preparation tank 1, respectively, 2 is a first esterification reaction tank, 2a Is a vent port provided in the upper part of the first esterification reaction tank 2, 2b is a catalyst supply port provided in the upper part of the first esterification reaction tank 2, 3 is a second esterification reaction tank, and 3a is a second Vent port provided in the upper part of the esterification reaction tank 3, 4 is a first polycondensation reaction tank, 4a is a vent port provided in the upper part of the first polycondensation reaction tank 4, 4b is a first polycondensation reaction 4 is a catalyst supply port provided at the upper part of 4, 5 is a second double condensation reaction tank, 5 a is a vent port provided at the upper part of the second double condensation reaction tank 5, 6 is a polymer extraction die, 7 is a pelletizer, 8 Is a filter installed in the reaction product flow path between the second esterification reaction tank 3 and the first polycondensation reaction tank 4, and 9 is between the first polycondensation reaction tank 4 and the second double condensation reaction tank 5. The filter 10 is installed in the reaction product channel between the first double condensation reaction tank 5 and the polymer extraction die 6, and is M1, M2, M3, M4, M5. Is a stirring device, G1, G2, G3, G4, and G5 are gear pumps, and P1, P2, P3, P4, and P5 are pipes.
[0021]
In FIG. 1, a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of 1,4-butanediol are respectively supplied to the slurry preparation tank 1 from the raw material supply ports 1a and 1b, and the stirring device M1 The mixture is made into a slurry, passed through the pipe P1 by the gear pump G1, and transferred to the first esterification reaction tank 2.
[0022]
The first esterification reaction tank 2 is a vertical reaction tank provided with a stirrer M2 having a vertical rotation axis, and in this reaction tank 2, an esterification reaction catalyst of a titanium compound is supplied from a catalyst supply port 2b, Usually, the esterification reaction is carried out under stirring of the stirring device M2 at a temperature of 150 to 280 ° C., preferably 180 to 265 ° C., usually 6.7 to 133 kPa, preferably 9.3 to 101 kPa, preferably 50 An oligomer having an esterification reaction rate of ˜90% is generated, and the oligomer is passed through the pipe P2 by the gear pump G2 and transferred to the second esterification reaction tank 2. On the other hand, by-product water, tetrahydrofuran, and unreacted 1,4-butanediol are extracted from a vent port 2a connected to a decompressor (not shown), and passed through a rectification tower (not shown). Then, unreacted 1,4-butanediol is returned to the first esterification reaction tank 2, and water and tetrahydrofuran are discharged out of the system.
[0023]
The second esterification reaction tank 3 is also a vertical reaction tank provided with a stirrer M3 having a vertical rotation axis. In the reaction tank 3, the temperature is usually 180 to 280 ° C., preferably 200 to 265 ° C., usually The esterification reaction is further carried out under the pressure of 6.7 to 133 kPa, preferably 9.3 to 101 kPa, with stirring by the stirring device M3, and preferably an oligomer having an esterification reaction rate of 90 to 99.9%. The oligomer is generated and passed through the pipe P3 by the gear pump G3 and transferred to the first polycondensation reaction tank 4. At that time, a filter 8 having an absolute filtration accuracy of 0.5 to 50 μm is installed in the middle of the pipe P3 which is a flow path of the reaction product, and the transferred oligomer is filtered through the filter 8. The On the other hand, by-product water, tetrahydrofuran, and unreacted 1,4-butanediol are extracted from a vent port 3a connected to a decompressor (not shown), and passed through a rectification tower (not shown). Then, unreacted 1,4-butanediol is returned to the second esterification reaction tank 3, and water and tetrahydrofuran are discharged out of the system.
[0024]
The first polycondensation reaction tank 4 is a vertical reaction tank provided with a stirrer M4 having a vertical rotation axis, and in the reaction tank 4, in the presence of the polycondensation reaction catalyst supplied from the catalyst supply port 4b, Alternatively, in the presence of the titanium compound supplied from the catalyst supply port 2b of the first esterification reaction tank 2, the temperature is usually 210 to 280 ° C, preferably 220 to 265 ° C, usually 0.7 to 27 kPa, preferably 1 Under a reduced pressure of 3 to 20 kPa, a polycondensation reaction is performed with stirring by the stirring device M4, and a prepolymer having an intrinsic viscosity of preferably 0.1 to 0.5 dl / g is generated. It is passed through the pipe P4 and transferred to the second double condensation reaction tank 5. At that time, a filter 9 having an absolute filtration accuracy of 5 to 50 μm is installed in the middle of the pipe P4 which is a flow path for the reaction product, and the prepolymer to be transferred is filtered through the filter 9. . On the other hand, by-product water, tetrahydrofuran, and unreacted 1,4-butanediol are withdrawn from the vent port 4a connected to a decompressor (not shown), and the total condenser (not shown) is connected. After that, it is cooled, liquefied and discharged out of the system.
[0025]
The second double condensation reaction tank 5 is a horizontal reaction tank provided with a stirrer M5 having a horizontal rotation axis. In the reaction tank 5, the temperature is usually 235 to 280 ° C., preferably 235 to 265 ° C., usually 1 The polycondensation reaction is further advanced under a reduced pressure of 3 kPa or less, preferably 0.7 kPa or less, with stirring by the stirring device M5, and a polymer having an intrinsic viscosity of preferably 0.6 to 1.3 dl / g is produced. The polymer is passed through the pipe P5 by the gear pump G5 and transferred to the polymer extraction die 6. At that time, a filter 10 having an absolute filtration accuracy of 10 to 50 μm is installed in the middle of the pipe P5 which is a flow path for the reaction product, and the polymer to be transferred is filtered through the filter 10. On the other hand, by-product water, tetrahydrofuran, and unreacted 1,4-butanediol are withdrawn from the vent port 5a connected to a decompressor (not shown), and a total condenser (not shown) is connected. After that, it is cooled, liquefied and discharged out of the system.
[0026]
The resin transferred to the polymer extraction die 6 is extracted in the form of a strand, and subsequently cut by a pelletizer 7 to form a pellet.
[0027]
In the above description, the first polycondensation reaction tank 4 and the second polycondensation reaction tank 4 are used as the filter 8 in the middle of the pipe P3 which is a reaction product flow path between the second esterification reaction tank 3 and the first polycondensation reaction tank 4. As a filter 9 in the middle of a pipe P4 that is a reaction product flow path between the double condensation reaction tank 5 and in the middle of a pipe P5 that is a reaction product flow path between the second double condensation reaction tank 5 and the polymer extraction die 6. Although the example which installed the filter in three places was shown as the filter 10, in this invention, it is not limited to several places, From the exit of the 1st esterification reaction tank 2 which is the first esterification reaction tank. One point may be provided as long as it is between the outlet of the polymer extraction die 6. Among them, from the viewpoint of filtration efficiency and the like, the filter 9 between the first polycondensation reaction tank 4 and the second double condensation reaction tank 5 or between the second double condensation reaction tank 5 and the polymer extraction die 6 is used. As in the case of the filter 10, between the outlet of the reactor immediately before the final polycondensation reactor and the inlet of the final polycondensation reactor, or from the outlet of the final polycondensation reactor to the outlet of the polymer extraction die It is preferable to install between.
[0028]
In the above description, the filter is installed at an intermediate position between the pipes constituting the reaction product flow path. However, the inlet or outlet of the esterification reaction tank or the polycondensation reaction tank, or the polymer extraction die It may be in the entrance or in the die, and a plurality of filters may be provided at each installation position.
[0029]
The polybutylene terephthalate resin obtained by the production method of the present invention has a reduced fish eye. For example, in a film having a thickness of 50 μm, the number of fish eyes having a nucleus having a size of 20 μm or more is 10/100 cm.²Or more, and 5/100 cm²It is also possible to:
[0030]
In addition, the resin granule after the polycondensation reaction obtained in the method for producing a polybutylene terephthalate resin of the present invention is subjected to an inert gas atmosphere or / and a reduced pressure of about 0.013 to 1.3 kPa. In general, the heat treatment is usually performed for about 5 to 20 hours at a temperature 5 to 50 ° C. lower than the melting point of the resin, preferably 10 to 40 ° C. lower than the melting point, while allowing the particles to flow so as not to stick to each other. Thus, by carrying out the solid phase polycondensation reaction, the degree of polymerization can be further increased, and the reaction by-products such as tetrahydrofuran and low-molecular oligomers can be reduced.
[0031]
【Example】
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.
Example 1
The same manufacturing equipment as shown in FIG. 1 is used except that the filter installation flow path is the flow path described later, and both raw materials are supplied at a ratio of 1.8 mol of 1,4-butanediol per 1 mol of terephthalic acid. 2976 parts by weight of slurry (9.06 mole part of terephthalic acid, 16.31 mole part of 1,4-butanediol) prepared by mixing in the slurry preparation tank 1 through the ports 1a and 1b and mixing with the stirring device M1 is the gear pump G1. Is passed through the pipe P1 and transferred to the first esterification reaction tank 2 adjusted to a temperature of 230 ° C. and a pressure of 101 kPa, and 3.14 parts by weight of tetrabutyl titanate is supplied from the catalyst supply port 2b. Was stirred for 2 hours to obtain an oligomer having an esterification reaction rate of 87.3%.
[0032]
Subsequently, the oligomer is passed through the pipe P2 by the gear pump G2, transferred to the second esterification reaction tank 3 adjusted to a temperature of 240 ° C. and a pressure of 101 kPa, and subjected to an esterification reaction for 1 hour with stirring by the stirring device M3. To obtain an oligomer having an esterification reaction rate of 98.0%, and the oligomer was passed through the pipe P3 by the gear pump G3 to adjust the temperature to 250 ° C. and the pressure to 6.7 kPa. In the presence of the titanium compound supplied from the catalyst supply port 2b of the first esterification reaction tank 2, and a polycondensation reaction is carried out for 2 hours under the stirring of the stirring device M4, so that the intrinsic viscosity is 0.24 dl / g. A prepolymer was obtained.
[0033]
Subsequently, the prepolymer was passed through the pipe P4 by the gear pump G4 and installed in the middle of the pipe P4 (corresponding to the installation flow path of the filter 9 in FIG. 1). A laminated metal mesh having an absolute filtration accuracy of 20 μm was used as a filter medium. After passing through a pleated cylindrical type filter, it is transferred to a second double condensation reaction tank 5 adjusted to a temperature of 250 ° C. and a pressure of 0.13 kPa, and further subjected to a polycondensation reaction for 3 hours with stirring by the stirring device M5. Proceeding to obtain a polymer with an intrinsic viscosity of 0.86 dl / g, passing the polymer through the pipe P5 by the gear pump G5, transferring it to the polymer extraction die 6, extracting it into a strand, cutting it with a pelletizer 7, and pellets As a result, polybutylene terephthalate resin pellets were produced.
[0034]
Next, the obtained polybutylene terephthalate resin pellets were supplied to a single screw extruder equipped with a T die and the cylinder temperature set at 270 ° C., melt-extruded into a film, and then held at a temperature of 58 to 62 ° C. By quenching with a metal cooling roll, the film was formed into a film having a thickness of 50 μm, and the number of fish eyes was measured by the method shown below. 4.2 / 100 cm²Met.
[0035]
Here, the esterification reaction rate, the intrinsic viscosity (IV) and the number of fish eyes were measured by the following methods.
Esterification reaction rate
The obtained oligomer was dissolved in N, N-dimethylformamide, and the acid value was measured by conductometric titration with an ethanolic aqueous solution of 0.1 mol% potassium hydroxide, and its acid value [X (meq / g)] From the following formula.
Esterification reaction rate = [(9.083-X) /9.083] × 100
[0036]
Intrinsic viscosity (IV)
By measuring the viscosity of a solution obtained by dissolving the obtained polymer in a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1) at a concentration of 1.0 g / dl at 30 ° C. using an Ubbelohde viscometer. Asked.
[0037]
Number of fish eyes
About the obtained film, 10cm square (100cm²) Was observed with a stereomicroscope with a magnification of 50 times, the number of fish eyes having nuclei of 20 μm or more in each location was counted, and the average value was calculated.
[0038]
Example 2
A pleated cylindrical filter using a metal nonwoven fabric having an absolute filtration accuracy of 30 μm as a filter medium was used, and the filter was installed in the middle of a pipe P5 between the second double condensation reaction tank 5 and the polymer extraction die 6. (Corresponding to the installation flow path of the filter 10 in FIG. 1), polybutylene terephthalate resin pellets were produced in the same manner as in Example 1. In this case, the esterification reaction rate of the oligomer at the outlet of the first esterification reaction tank 2 is 87.0%, the esterification reaction rate of the oligomer at the outlet of the second esterification reaction tank 3 is 98.1%, the first weight The intrinsic viscosity of the prepolymer at the outlet of the condensation reaction tank 4 is 0.25 dl / g, the intrinsic viscosity of the finally obtained polymer is 0.85 dl / g, and the number of fish eyes in the film is 3.4. / 100cm²Met.
[0039]
Comparative Example 1
Polybutylene terephthalate resin pellets were produced in the same manner as in Example 1 except that no filter was used. At that time, the esterification reaction rate of the oligomer at the outlet of the first esterification reaction tank 2 was 87.3%, the esterification reaction rate of the oligomer at the outlet of the second esterification reaction tank 3 was 98.2%, The intrinsic viscosity of the prepolymer at the outlet of the condensation reaction tank 4 is 0.25 dl / g, the intrinsic viscosity of the finally obtained polymer is 0.86 dl / g, and the number of fish eyes in the film is 15.8. / 100cm²Met.
[0040]
【The invention's effect】
According to the present invention, in a method for producing a polybutylene terephthalate-based resin that undergoes an esterification reaction in the presence of an esterification reaction catalyst for a titanium compound, a method for producing a polybutylene terephthalate-based resin with less fish eye, and a method obtained thereby. The polybutylene terephthalate-based resin can be provided.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of a production apparatus used in the production method of a polybutylene terephthalate resin of the present invention.
[Explanation of symbols]
1: Slurry preparation tank
1a, 1b: Raw material supply port
2: First esterification reactor
2a: Vent port
2b: catalyst supply port
3: Second esterification reactor
3a: Vent port
4: First polycondensation reaction tank
4a: Vent port
4b: catalyst supply port
5: Second double condensation reactor
5a: Vent port
6: Polymer extraction die
7: Pelletizer
8, 9, 10: Filter
M1, M2, M3, M4, M5: Stirring device
G1, G2, G3, G4, G5: Gear pump
P1, P2, P3, P4, P5: Piping

Claims (4)

  A dicarboxylic acid component having terephthalic acid as a main component and a diol component having 1,4-butanediol as a main component in a single or plural esterification reaction tanks as titanium atoms with respect to the theoretical yield of resin as 30 to 30 Esterification reaction in the presence of 300 ppm titanium compound esterification reaction catalyst, then polycondensation reaction in one or more polycondensation reaction tanks, and then extracted from the polymer extraction die to produce polybutylene terephthalate resin The polybutylene terephthalate resin is characterized in that a filter is installed in the reaction product flow path between the outlet of the first esterification reaction tank and the outlet of the polymer extraction die and the reaction product is passed through the filter. Manufacturing method.   The method for producing a polybutylene terephthalate-based resin according to claim 1, wherein the filter is installed between the outlet of the reaction tank immediately before the final polycondensation reaction tank and the inlet of the final polycondensation reaction tank.   The method for producing a polybutylene terephthalate resin according to claim 1 or 2, wherein the flow path for the filter is between the outlet of the final polycondensation reaction tank and the outlet of the polymer extraction die.   The method for producing a polybutylene terephthalate resin according to any one of claims 1 to 3, wherein the polycondensation reaction is performed continuously.

Images