JP3911251B2 - Method for producing polybutylene terephthalate resin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polybutylene terephthalate resin.Manufacturing methodAbout. More specifically, the present invention relates to foreign matter, haze, tetrahydrofuran content, etc.ButPolybutylene terephthalate tree with reduced moldability and good formabilityGreasyIt relates to a manufacturing method.
[0002]
[Prior art]
Polybutylene terephthalate resin, a typical engineering plastic among thermoplastic polyester resins, is easy to mold, mechanical properties, heat resistance, chemical resistance, aroma retention, other physical and chemical properties Due to its excellent properties, it is widely used in automobile parts, electrical / electronic parts, precision equipment parts, etc., but in recent years, it has been widely used in the fields of films, sheets, monofilaments, fibers, etc. by taking advantage of its superior properties. It has come to be.
[0003]
Polybutylene terephthalate is generally produced by polycondensation using terephthalic acid or its dialkyl ester and 1,4-butanediol as main raw materials through an esterification reaction or a transesterification reaction. The extracted polymer contains a solid substance due to the catalytic substance, which not only deteriorates the transparency of the product and causes foreign matter defects (fish eyes), but also causes a decrease in strength and elongation. There was a problem.
[0004]
Polybutylene terephthalate resin is produced through an esterification reaction when the raw material is a dicarboxylic acid, and through a transesterification reaction when the raw material is a dialkyl ester of a dicarboxylic acid. -There is a side reaction that generates tetrahydrofuran (THF) or the like by decomposition of butanediol, and particularly in the case of a so-called continuous polymerization method in which a raw material is continuously supplied to continuously obtain a polybutylene terephthalate resin, a dicarboxylic acid is used as the raw material. Side reactions were prominent when used. Such side reactions are problematic because they result in a decrease in the yield of the raw material 1,4-butanediol and the quality of the product polybutylene terephthalate resin.
[0005]
With respect to these problems, for example, Patent Documents 1 and 2 propose to install a filter in a line connecting reaction vessels for producing polybutylene terephthalate with respect to the reduction of foreign matters in the polybutylene terephthalate resin. However, since filtration cannot remove foreign matters below the filter openings, the only way to reduce foreign matters is to reduce the openings, but if the filter openings are reduced, the line pressure loss increases. Therefore, in order to maintain the flow rate, there is a problem that facilities such as a pump and piping become excessive. In addition, since the filter life is inevitably shortened, the complexity of switching and replacing the filter increases, which has a great adverse effect on productivity and safety. Furthermore, since the polymer is subjected to high shear when passing as the filter opening becomes smaller, there is a problem that deterioration due to shear heat generation increases.
[0006]
Moreover, it is known that the by-product of tetrahydrofuran is suppressed by increasing the catalyst concentration as a reduction method thereof. For example, Patent Document 3 discloses a high molar ratio of 1,4-butanediol and terephthalic acid, Esterification reactions under conditions of high catalyst concentration, high temperature and low pressure have been proposed. However, this method has a problem that catalyst residues based on a high catalyst concentration cause an increase in foreign matters in the product, and a high temperature and a high catalyst concentration cause an increase in side reactions other than the generation of THF. Moreover, the low pressure setting causes an increase in 1,4-butanediol discharged out of the system as a distillate, and has problems such as excessive facilities.
[0007]
On the other hand, Patent Document 4 defines the molar ratio of 1,4-butanediol and terephthalic acid, and suppresses the concentration of the organic titanium compound to a value calculated using the molar ratio, thereby reducing the generation of catalyst-derived foreign matter. We are trying to suppress side reactions that generate THF, but the basis of this technology is that the concentration of organotitanium compounds is set low, so that the catalyst activity that occurs and the increase in THF production, which is a side reaction, are compensated by the addition of organotin compounds. There was a problem that the polybutylene terephthalate obtained had a poor color tone and the catalyst residue was not essentially reduced. Moreover, compared with the example of patent document 3, the low reaction temperature setting has resulted in the increase in esterification reaction time, and the significant improvement was calculated | required also from a viewpoint of productivity.
[0008]
[Patent Document 1]
JP 2000-336162 A
[Patent Document 2]
JP 2001-270937 A
[Patent Document 3]
Japanese Patent Laid-Open No. 62-195017
[Patent Document 4]
Japanese Patent Laid-Open No. 10-330469
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a polybutylene terephthalate resin which is excellent in mechanical strength and color tone, has reduced haze and foreign matter, and can be suitably used for films, monofilaments, fibers and the like.
It is another object of the present invention to provide a polybutylene terephthalate resin which has a short injection molding cycle, has excellent moldability and color tone, generates little gas from a molded product, and can be suitably used for electric / electronic parts such as relay parts.
[0010]
Another object of the present invention is to suppress side reactions such as the formation of THF during esterification or transesterification reaction, improve productivity, and at the same time reduce haze and foreign matter, and have good color tone, polybutylene terephthalate resin It is in providing the manufacturing method of.
[0012]
[Means for Solving the Problems]
  As a result of studies to solve the above-mentioned problems, the present invention has found that the above-mentioned problems can be solved when stirring in the polybutylene terephthalate resin production reaction is performed under specific conditions.
  That is, the gist of the present invention is as follows.In the presence of a catalyst, a dicarboxylic acid component mainly composed of terephthalic acid or a dialkyl ester thereof and a diol component mainly composed of 1,4-butanediol.ContinuouslyIn the method of producing polybutylene terephthalate by carrying out esterification or transesterification and then polycondensation, the stirring energy Q per unit volume of the reactant added to the reactant in the esterification or transesterification step (KJ / m^Three)(1)Meet the relationshipIn addition, the molar ratio of the raw material terephthalic acid or terephthalic acid dialkyl ester supplied to the esterification reactor or transesterification reactor per unit time and 1,4-butanediol satisfies the following formula (2):A process for producing a polybutylene terephthalate resin, characterized in that:
  Q ≧ 1500 kJ / m^Three                (1)
B / T = 2.5-4.5 (mol / mol) (2)
(However, B is the number of moles of 1,4-butanediol supplied from the outside to the esterification or transesterification reaction tank per unit time, and T is supplied from the outside to the esterification or transesterification reaction tank per unit time. The number of moles of terephthalic acid or terephthalic acid dialkyl ester)
[0013]
DETAILED DESCRIPTION OF THE INVENTION
(resin)
The polybutylene terephthalate resin of the present invention contains a titanium compound. In some cases, a tin compound may be included.
The polybutylene terephthalate resin of the present invention has the following formula:
Ti / C / H / O = 1.0 / x / y / z
(Wherein x takes a value from 1.0 to 10.0, y takes a value from 1.0 to 10.0, and z takes a value from 1.0 to 10.0) It is essential to contain a particulate titanium-containing substance (hereinafter referred to as an organic titanium compound). Here, preferably, x is 2.0 or more and 8.0 or less, y is 2.0 or more and 8.0 or less, z is 1.0 or more and 5.0 or less, more preferably x is 3.0. The above is 6.0 or less, y is 3.0 or more and 6.0 or less, z is 2.0 or more and 4.0 or less, and particularly preferably, x is 4.0 or more and 6.0 or less, and y is 3.0. 5.0 or more, z is 2.0 or more and 4.0 or less, and most preferably, x is 4.5 or more and 5.5 or less, y is 3.5 or more and 5.0 or less, and z is 2.5. It is 4.0 or less.
[0014]
The composition of the organotitanium compound is based on the elements collected by the methods described below, such as elemental analysis by EPMA, EDX, organic elemental analysis, TG-DTA analysis, infrared spectrum, X-ray diffraction (XRD), pyrolysis GC, etc. It can be obtained by combining analysis methods. That is, the form of the organic titanium compound is not limited as long as it is collected and analyzed by the method described in the present specification and satisfies the requirements described in the present specification.
The organotitanium compound has a smaller light shielding effect than titanium oxide, and the deterioration of transparency is greatly improved. Moreover, since it has a function as a crystallization nucleating agent, it has the effect of increasing the crystallization speed of polybutylene terephthalate and shortening the molding cycle.
[0015]
The content of the organic titanium compound needs to be 0.01 to 250 ppm by weight with respect to the polybutylene terephthalate resin, preferably 0.1 to 200 ppm, more preferably 1 to 150 ppm, particularly preferably. Is 5 or more and 100 ppm or less. If it exceeds 250 ppm, foreign matter and defects in the product are formed, and if it is less than 0.01 ppm, improvement in the crystallization rate cannot be seen.
The content of the organic titanium compound is such that polybutylene terephthalate resin is dissolved in hexafluoroisopropanol / chloroform = 1/1 (volume ratio), centrifuged, and finally several times hexafluoroisopropanol / chloroform = 1/1 (volume). The ratio can be quantified by washing at a specific ratio), collecting and drying. When the concentration is low, more accurate quantification can be performed by taking a large amount of sample and repeatedly centrifuging.
[0016]
Among the organic titanium compounds contained in the polybutylene terephthalate resin of the present invention, an organic titanium compound having a large particle size tends to be a foreign substance in the product and causes a reduction in the commercial value and mechanical properties of the molded product. The above organic titanium compound is preferably not more than 200 ppm by weight with respect to polybutylene terephthalate, more preferably not more than 100 ppm, particularly not more than 50 ppm, and particularly preferably not more than 10 ppm. An organic titanium compound having a particle size of 5 μm or more is prepared by dissolving a polybutylene terephthalate resin in hexafluoroisopropanol / chloroform = 1/1 (volume ratio), and filtering with a polytetrafluoroethylene membrane filter having a pore size of 5 μm. It can be determined as the amount washed thoroughly and finally collected on the filter.
[0017]
The organic titanium compound includes titanium compounds such as titanium alcoholate and titanium phenolate, organic acids such as terephthalic acid, isophthalic acid, benzoic acid and acetic acid, alcohols such as ethanediol, 1,4-butanediol and pentaerythritol, etc. A so-called polymerization internal addition method is typically used in which an organic compound is synthesized at a stage of intermediates such as raw materials and oligomers. In particular, a polymerization vessel is used in parallel at the stage of proceeding the polymerization reaction of polybutylene terephthalate. It is preferable from the viewpoint of simplicity to synthesize and disperse in the resin. In addition, it can be mixed with polybutylene terephthalate resin and kneaded with an extruder or the like.
[0018]
The polybutylene terephthalate resin in the present invention is obtained by using titanium or titanium and tin as a catalyst. The total concentration of titanium and tin metal atoms in the polybutylene terephthalate resin is preferably 20 to 250 ppm, 30 to 150 ppm, particularly 30 to 120 ppm, particularly 30 to 90 ppm is preferable. These metal atom h amounts can be measured using a method such as atomic emission or Induced Coupled Plasma (ICP) after recovering the metal in the polymer by a method such as wet ashing. If it is 20 ppm or less, the reaction rate during the production reaction of the polybutylene terephthalate resin tends to be slow, and if it is 250 ppm or more, there is a tendency that there are many undesirable foreign substances in the resin.
[0019]
The polybutylene terephthalate resin of the present invention preferably has an intrinsic viscosity of 0.5 to 1.5 dL / g measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1). It is more preferably 0.6 to 1.4 dL / g, and still more preferably 0.7 to 1.3 dL / g. If the intrinsic viscosity is less than 0.5 dL / g, the mechanical strength of the molded product may be insufficient. When the intrinsic viscosity exceeds 1.5 dL / g, the melt viscosity becomes high, the fluidity is deteriorated, and the moldability tends to be poor.
[0020]
In the present invention, the terminal carboxyl group concentration of the polybutylene terephthalate resin is not limited, but if it is too much, the hydrolysis resistance of the polybutylene terephthalate resin is deteriorated, and if it is too small, the polymerizability is deteriorated, so that it is 1 or more and 40 μeq / g. Or less, more preferably 2 to 30 μeq / g, particularly 3 to 25 μeq / g, and particularly preferably 5 to 20 μeq / g.
The terminal carboxyl group concentration of the polybutylene terephthalate resin can be determined by dissolving the resin in an organic solvent and titrating with an alkali solution such as a sodium hydroxide solution.
[0021]
In the present invention, the tetrahydrofuran content in the polybutylene terephthalate resin is preferably 200 ppm (weight ratio) or less, more preferably 180 ppm or less, and particularly preferably 150 ppm or less. The tetrahydrofuran content in the resin can be determined by immersing the resin pellets in water, treating the pellets in a pressure-resistant airtight container at 120 ° C. for 6 hours, and quantifying the amount of tetrahydrofuran eluted in the water by gas chromatography. When the amount of tetrahydrofuran in the polybutylene terephthalate is large, gas is generated when the molded product is used at a high temperature, which causes corrosion of electrical contacts of electrical and electronic parts such as relay parts.
[0022]
The temperature-falling crystallization temperature of the polybutylene terephthalate resin in the present invention is preferably 170 ° C. or higher, and particularly preferably 173 ° C. or higher, particularly 175 ° C. or higher. The temperature-falling crystallization temperature of the polybutylene terephthalate resin in the present invention is the temperature of an exothermic peak due to crystallization that appears when the resin is melted by using a differential scanning calorimeter and cooled at a temperature-falling rate of 20 ° C./min. The temperature-falling crystallization temperature corresponds to the crystallization speed, and the higher the temperature-falling crystallization temperature, the faster the crystallization speed. Therefore, the cooling time can be shortened during the injection molding, and the productivity can be increased. When the temperature-falling crystallization temperature is low, crystallization takes time during injection molding, and the cooling time after injection molding must be lengthened, and the molding cycle tends to be extended and productivity tends to be lowered.
[0023]
The polybutylene terephthalate resin in the present invention is a polymer having a structure in which a terephthalic acid unit and a 1,4-butanediol unit are ester-bonded, and 50 mol% or more of the dicarboxylic acid unit is composed of a terephthalic acid unit. 50 mol% or more consists of 1,4-butanediol units. Among them, terephthalic acid units preferably occupy 70 mol% or more, more preferably 80 mol% or more, particularly 95 mol% or more of all dicarboxylic acid units, and 70 mol% or more, more preferably 80 mol of diol units. It is preferable that 1,4-butanediol units occupy% or more, particularly 95 mol% or more. If the amount of terephthalic acid units or 1,4-butanediol units is less than 50 mol%, the crystallization rate of the polybutylene terephthalate resin is lowered, and the moldability is deteriorated.
[0024]
In the present invention, the dicarboxylic acid component other than terephthalic acid is not particularly limited, and examples thereof include phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, and 4,4′-benzophenone dicarboxylic acid. Acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, aromatic dicarboxylic acid such as 2,6-naphthalenedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexane Examples include alicyclic dicarboxylic acids such as dicarboxylic 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. be able to.
[0025]
These dicarboxylic acid components can be donated to the reaction as a dicarboxylic acid or as an alkyl ester of a dicarboxylic acid, preferably a dialkyl ester, and may be a mixture of a dicarboxylic acid and a dicarboxylic acid alkyl ester. There are no particular restrictions on the alkyl group of the dicarboxylic acid alkyl ester, but if the alkyl group is long, the boiling point of the alkyl alcohol produced during the transesterification reaction will increase, and the reaction solution will not volatilize, resulting in polymerization as a terminator. In view of this, an alkyl group having 4 or less carbon atoms is preferable, and a methyl group is particularly preferable.
[0026]
In the present invention, the diol component other than 1,4-butanediol is not particularly limited. For example, ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, polypropylene glycol, polytetramethylene Glycol, dibutylene glycol, 1,5-pentanediol, neopentylglycol, 1,6-hexanediol, aliphatic diols such as 1,8-octanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, alicyclic diols such as 1,4-cyclohexanedimethylol, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane, bis (4 -Hydroxyfe Etc. and aromatic diols such as Le) sulfone.
[0027]
In the present invention, a hydroxycarboxylic acid such as lactic acid, glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, p-β-hydroxyethoxybenzoic acid, alkoxycarboxylic acid, etc. Monofunctional components such as acid, stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane Trifunctional or higher polyfunctional components such as trimethylolpropane, glycerol and pentaerythritol can be used as the copolymerization component.
[0028]
  The production method of the polybutylene terephthalate resin of the present invention is based on a conventional production method of a polybutylene terephthalate resin. These known methods are roughly divided into a so-called direct polymerization method using a dicarboxylic acid as a main raw material, and a dicarboxylic acid dialkyl ester. There is a transesterification method using as a main raw material. The former has the difference that water is produced in the initial esterification reaction, and the latter produces alcohol in the initial transesterification reaction. However, the availability of raw materials, the ease of processing of the distillate, and the present invention are different. The direct polymerization method is preferable from the viewpoint of the improvement effect. These esterification reactions or transesterification reactions, and subsequent polycondensation reactionsIsContinuous method from the viewpoint of productivity and product uniformityAdopt.
[0029]
As an example of the continuous direct polymerization method, the dicarboxylic acid component containing terephthalic acid as a main component and the diol component containing 1,4-butanediol as a main component in a single-stage or multi-stage esterification reaction tank, In the presence of an esterification reaction catalyst, the temperature is usually from 180 to 260 ° C, preferably from 200 to 240 ° C, particularly preferably from 210 to 235 ° C, and usually from 10 to 300 kPa, preferably from 10 to 130 kPa, particularly preferably from 60 to Under the pressure of 90 kPa, the esterification reaction is carried out continuously usually for 0.5 to 10 hours, preferably 0.5 to 5 hours, more preferably 1 to 3 hours. The oligomer is transferred to a polycondensation reaction tank and is preferably continuously, usually in the presence of a polycondensation reaction catalyst in one or more polycondensation reaction tanks. A method of subjecting the polycondensation reaction to a temperature of 280 ° C., preferably 220 to 265 ° C., usually 27 kPa or less, preferably 20 kPa or less, particularly preferably 13 kPa or less, with stirring for 2 to 12 hours, preferably 3 to 10 hours. Is mentioned.
[0030]
On the other hand, as an example of the transesterification method, the dicarboxylic acid ester component mainly composed of a dialkyl ester of terephthalic acid and the diol component mainly composed of 1,4-butanediol are transesterified in one or more stages. In the reaction vessel, in the presence of a transesterification catalyst, the temperature is usually 110 to 260 ° C, preferably 140 to 240 ° C, particularly preferably 180 to 220 ° C, and usually 10 to 300 kPa, preferably 10 to 130 kPa, particularly Preferably, the transesterification reaction is carried out continuously under a pressure of 60 to 101 kPa for 0.5 to 10 hours, preferably 0.5 to 5 hours, and the resulting oligomer as a transesterification reaction product is a polycondensation reaction tank. In a single-stage or multiple-stage polycondensation reaction tank, preferably continuously in the presence of a polycondensation reaction catalyst. 210-280 ° C, preferably 220-265 ° C, usually 27 kPa or less, preferably 20 kPa or less, particularly preferably 13 kPa or less, and a polycondensation reaction under stirring for 2-12 hours, preferably 3-10 hours The method of letting it be mentioned.
[0031]
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, and while being cooled with water or after being cooled with water, it is cut with a cutter and pelletized. It is made of granular material.
[0032]
As the esterification or transesterification reaction catalyst in the present invention, a titanium compound is suitably used. Specific examples of the titanium compound include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, tetrabutyl titanate, and tetraphenyl titanate. Typical examples include titanium phenolate such as tetrabutyl titanate. The amount used is not particularly limited, but if it is too much, not only will it cause foreign substances, but it will also cause deterioration reaction and heat generation of the polymer, and if it is too little, the main reaction rate will decrease and side reactions will occur. Therefore, the titanium atom is usually 1 to 250 ppm, preferably 5 to 200 ppm, more preferably 5 to 150 ppm, particularly preferably 20 to 100 ppm, and more preferably 30 to 90 ppm as a titanium atom with respect to the obtained polybutylene terephthalate resin. .
[0033]
On the other hand, when emphasis is placed on foreign matter suppression and transparency improvement, titanium atoms are preferably 1 to 65 ppm, more preferably 10 to 50 ppm, and particularly preferably 20 to 45 ppm with respect to the obtained polybutylene terephthalate resin. is there.
[0034]
Further, as an esterification or transesterification reaction catalyst, in addition to the titanium compound, for example, dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, triethyl Tin hydroxide, triphenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, methylstannic acid, ethylstannic acid, butylstann Non-acid, tin compounds, magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, mug Nitrosium alkoxide, magnesium hydrogen phosphate, magnesium etc. compounds, calcium acetate, calcium hydroxide, calcium carbonate, calcium oxide, calcium alkoxide, can be used calcium hydrogen phosphate, calcium etc. compounds.
[0035]
In addition, as the polycondensation reaction catalyst, a catalyst added at the time of esterification or transesterification reaction may be used as a polycondensation reaction catalyst, and a new catalyst may not be added. The amount used at that time is not particularly limited, but if it is too large, the above-mentioned problems occur. Therefore, as a metal atom with respect to the polybutylene terephthalate resin that is usually obtained, it is 300 ppm or less, preferably 150 ppm or less. The amount used is preferably 100 ppm or less, particularly preferably 50 ppm or less, and is different from the esterification reaction catalyst added during the esterification reaction, for example, antimony compounds such as antimony trioxide, germanium dioxide, germanium tetroxide, etc. A germanium compound or the like may be newly added.
[0036]
In addition, from the viewpoints of suppressing foreign matter, ensuring polymerizability, and color tone, the total metal concentration of titanium atoms or titanium atoms and tin atoms with respect to the polybutylene terephthalate resin needs to be 20 to 250 ppm, 30 to 150 ppm, particularly 30 to 120 ppm, particularly 30 to 90 ppm is preferable.
On the other hand, when emphasis is placed on foreign matter suppression, the amount of titanium atom or the total metal content of titanium atom and tin atom is preferably 1 to 65 ppm, more preferably 10 to 50 ppm, relative to the polybutylene terephthalate resin obtained. Particularly preferred is 20 to 45 ppm.
[0037]
From the same point of view, it is preferable that the metal concentration of titanium atoms or the total of titanium atoms and tin atoms is 15 to 230 ppm, more preferably 30 to 230 ppm with respect to the oligomer obtained by the above esterification or transesterification reaction. 100 ppm. The amount of these metals can be measured using atomic emission, atomic absorption, Induced Coupled Plasma (ICP), etc. after recovering the metal in the polymer or oligomer by a method such as wet ashing.
[0038]
When the esterification rate or transesterification rate of the oligomer obtained by the esterification or transesterification reaction is 90% or more, if the number average molecular weight of the oligomer is too large, the polycondensation rate is lowered in the post-polymerization step. 1000 or less, more preferably 700 or less, particularly preferably 600 or less, and most preferably 500 or less. Moreover, when the terminal vinyl group density | concentration of an oligomer is high, since the deterioration of the color tone of a polymer and the fall of solid phase polymerizability will be caused, 1 microeq / g or less is preferable.
[0039]
The number average molecular weight of the oligomer obtained by esterification or transesterification can be determined by vapor osmometer, end group titration, end group determination by NMR, etc., and the end vinyl group concentration can be determined by 1H-NMR. .
[0040]
In the esterification reaction, transesterification reaction, and 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, -Antioxidants such as phosphorus compounds such as -di-t-butylphenyl) phosphite, paraffin wax, microcrystalline wax, polyethylene wax, long chain fatty acids represented by montanic acid and montanic acid ester, esters thereof, silicone oil, etc. Other additives such as a mold release agent may be present.
[0041]
The esterification or transesterification reaction tank is not particularly limited as long as it is a reaction tank having a stirrer, and is of a type such as a vertical stirring complete mixing tank, a vertical heat convection mixing tank, and a tower-type continuous reaction tank. Any of them may be used, or a single tank or a plurality of tanks of the same kind or different kinds in series may be used.
A well-known stirrer can be used. In addition to the usual type consisting of a power unit and bearings, shafts, and stirring blades, a high-speed rotating type such as a turbine stator type high-speed rotating stirrer, disk mill type stirrer, rotor mill type stirrer Can also be used.
[0042]
There is no limitation on the form of stirring, and in addition to the normal stirring method in which the reaction solution in the reaction tank is directly stirred from the top, bottom, side, etc. of the reaction tank, a part of the reaction solution is piped outside the reactor, etc. It is possible to take a method of circulating the reaction liquid by taking it out with a line mixer and the like.
Known types of stirring blades can be selected, and specific examples include propeller blades, screw blades, turbine blades, fan turbine blades, disk turbine blades, fouller blades, full zone blades, Max blend blades, and the like.
[0043]
One of the characteristics of the method for producing the polybutylene terephthalate resin of the present invention is that the stirring energy Q (kJ / m) per unit volume of reactant added to the reactant in the esterification reaction step or transesterification step.^Three)But,
Q ≧ 1500 kJ / m^Three
Is to satisfy.
[0044]
Here, when the batch method is used, the reaction volume is set to V (m^Three), The stirring power to be applied is P (kw), and the reaction time is t (sec), Q = P × t / V, and the tank in which the esterification or transesterification reaction is performed satisfies the relationship of the following formula: .
Q = P × t / V ≧ 1500 kJ / m^Three
Q is more preferably 2000 kJ / m^ThreeAbove, particularly preferably 3000 kJ / m^ThreeAbove, optimally 4000 kJ / m^ThreeThat's it.
Here, the stirring power P can be detected by a method of installing a torque meter, a power detector or the like on the stirring shaft.
[0045]
In addition, when using a so-called continuous method in which raw materials are continuously supplied to the esterification reaction step or the transesterification reaction step to obtain a polymer continuously, the total supply amount of raw materials per unit time is q (m^Three/ Sec) and Q = P / q when the stirring power to be applied is P (kw), and the relationship of the following formula is satisfied in the tank for the esterification or transesterification reaction.
Q = P / q ≧ 1500 kJ / m^Three
[0046]
In the above, the total supply amount q per unit time means terephthalic acid or terephthalic acid dialkyl ester and, if necessary, a small amount of a copolymerized dicarboxylic acid component, 1,4-butanediol and, if necessary, a small amount of other copolymer. The volume of the polymerization diol component supplied to the esterification reaction tank. For example, when the raw material is prepared and supplied as a slurry with terephthalic acid and 1,4-butanediol, the volume of the slurry. For example, dimethyl terephthalate Is in a molten state and is supplied to the reaction vessel separately from 1,4-butanediol, the sum of the volume of dimethyl terephthalate and the volume of 1,4-butanediol respectively supplied. It should be noted that 1,4-butanediol collected in the distillation system and returned to the reaction tank, 1,4-butanediol refluxed in the reflux condenser, and the like are excluded.
[0047]
More preferably, 2000 kJ / m^ThreeAbove, particularly preferably 3000 kJ / m^ThreeAbove, optimally 4000 kJ / m^ThreeThat's it.
Q is 1500kJ / m^ThreeBelow, the apparent main reaction rate becomes slower and the side reaction emerges. At the same time, the deactivation of the catalyst proceeds, and particles with high concealment effect derived from the deactivated catalyst and foreign matters having a large particle size are likely to be generated. As a result, there is a tendency that inconveniences such as deterioration in transparency of the product, increase in foreign matters, and deterioration in hydrolysis resistance are likely to occur.
[0048]
  In producing the polybutylene terephthalate resin of the present invention, when continuously performing esterification or transesterification reaction, terephthalic acid or terephthalic acid dialkyl ester supplied to the reaction vessel from the outside per unit time, The molar ratio with 4-butanediol satisfies the following formula:is important.
B / T =2.5~ 4.5 (mol / mol)
(However, B is the number of moles of 1,4-butanediol supplied from the outside to the esterification or transesterification reaction tank per unit time, and T is supplied from the outside to the esterification or transesterification reaction tank per unit time. The number of moles of terephthalic acid or terephthalic acid dialkyl ester)
[0049]
  Above all, B / T =2.5To 4.0, more preferably 2.6 to 3.5, and particularly preferably 2.7 to 3.3. B / T is2.5If it is smaller, the catalyst-derived foreign matter tends to increase. If it is larger than 4.5, not only the thermal efficiency decreases, but also by-products such as tetrahydrofuran tend to increase..
[0050]
In the present invention, 1,4-butanediol supplied to the reaction vessel from the outside is independent of these other than 1,4-butanediol supplied together with terephthalic acid or dialkyl terephthalate as a raw slurry or liquid. 1,4-butanediol fed to the reactor, such as 1,4-butanediol collected in the distillation system and returned to the reaction tank, 1,4-butanediol refluxed by the reflux condenser, etc. from outside the reaction tank This is the sum of 1,4-butanediol entering the reaction vessel.
[0051]
One or a plurality of tanks for performing the esterification reaction or the transesterification reaction can be installed. However, the distinction between the esterification reaction tank or the transesterification reaction tank and the polycondensation reaction tank in the present invention is continuous polymerization by a direct polymerization method. In this case, the case where the esterification rate represented by the following formula (1) is 80% or less at the inlet of the reactor is defined as an esterification tank, and the case where it exceeds 80% is defined as a polycondensation reaction tank. Similarly, in the case of continuous polymerization by the transesterification method, the case where the transesterification rate represented by the following formula (2) is 80% or less is regarded as an esterification tank, and the case where it exceeds 80% is regarded as a polycondensation reaction tank. .
Esterification rate = (saponification value−acid value) × 100 / saponification value (1)
(Here, the acid value is a value obtained by dissolving the oligomer in dimethylformamide and alkali titrating, and the saponification value is a value obtained by alkaline hydrolysis of the oligomer and back titrating with acid.)
[0052]
Transesterification rate = (molar concentration of terephthalic acid unit × 2-methyl ester equivalent) × 100 / (molar concentration of terephthalic acid unit × 2) (2)
(Here, the molar concentration of the terephthalic acid unit and the equivalent amount of methyl ester were determined by dissolving the oligomer in hexafluoroisopropanol / deuterated chloroform = 3/7 (v / v), measuring 1H-NMR, and comparing each signal intensity ratio. Can be obtained from.)
[0053]
There is no restriction | limiting in particular in the type of the polycondensation reaction tank used for this invention, For example, a vertical stirring polymerization tank, a horizontal stirring polymerization tank, a thin film evaporation type polymerization tank etc. can be mentioned. The number of polycondensation reaction tanks can be one, or a plurality of tanks of the same or different types can be connected in series. It is preferable to select a horizontal stirring polymerization machine having a thin film evaporation function excellent in renewability, plug flow property, and self-cleaning property.
[0054]
The polybutylene terephthalate resin obtained by the production method of the present invention has an intrinsic viscosity of 0.5 or more and 1.5 dL / g or less measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1). In particular, it is preferably 0.6 or more and 1.4 dL / g or less, and particularly preferably 0.7 or more and 1.3 dL / g or less. When the intrinsic viscosity is less than 0.5 dL / g, the mechanical strength of the molded product becomes insufficient, and when the intrinsic viscosity exceeds 1.5 dL / g, the melt viscosity increases, the fluidity deteriorates, and molding is performed. It becomes inferior.
[0055]
A reinforcement filler can be mix | blended with the polybutylene terephthalate resin of this invention. The reinforcing filler to be blended is not particularly limited. For example, glass fibers, carbon fibers, silica / alumina fibers, zirconia fibers, boron fibers, boron nitride fibers, silicon nitride potassium titanate fibers, metal fibers and other inorganic fibers, aromatics Examples thereof include organic fibers such as polyamide fibers and fluororesin fibers. These reinforcing fillers can be used alone or in combination of two or more. In these, an inorganic filler can be used suitably and a glass fiber can be used especially suitably. When the reinforcing filler is an inorganic fiber or an organic fiber, the average fiber diameter is not particularly limited, but is preferably 1 to 100 μm, more preferably 2 to 50 μm, and more preferably 3 to 30 μm. More preferably, it is especially preferable that it is 5-20 micrometers. Moreover, although there is no restriction | limiting in particular also in average fiber length, it is preferable that it is 0.1-20 mm, and it is more preferable that it is 1-10 mm.
[0056]
In order to improve the interfacial adhesion with the polybutylene terephthalate resin, it is preferable to use a reinforcing filler surface-treated with a sizing agent or a surface treatment agent. Examples of the sizing agent or surface treatment agent include functional compounds such as epoxy compounds, acrylic compounds, isocyanate compounds, silane compounds, and titanate compounds. The reinforcing filler can be surface-treated in advance with a sizing agent or a surface treatment agent, or, when preparing a polybutylene terephthalate resin composition, surface treatment is performed by adding a sizing agent or a surface treatment agent. You can also. The addition amount of the reinforcing filler is preferably 0 to 150 parts by weight and more preferably 5 to 100 parts by weight with respect to 100 parts by weight of the polybutylene terephthalate resin.
[0057]
Another filler can be mix | blended with the polybutylene terephthalate resin of this invention with a reinforcing filler. Other fillers to be blended include, for example, plate-like inorganic fillers, ceramic beads, asbestos, wollastonite, talc, clay, mica, zeolite, kaolin, potassium titanate, barium sulfate, titanium oxide, silicon oxide, oxidation Examples thereof include aluminum and magnesium hydroxide. By blending the plate-like inorganic filler, the anisotropy and warpage of the molded product can be reduced. Examples of the plate-like inorganic filler include glass flakes, mica, and metal foil. Among these, glass flakes can be particularly preferably used.
[0058]
A flame retardant can be blended with the polybutylene terephthalate resin of the present invention in order to impart flame retardancy. There is no restriction | limiting in particular in the flame retardant to mix | blend, For example, an organic halogen compound, an antimony compound, a phosphorus compound, another organic flame retardant, an inorganic flame retardant etc. can be mentioned. Examples of the organic halogen compound include brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol A, pentabromobenzyl polyacrylate and the like. Examples of the antimony compound include antimony trioxide, antimony pentoxide, and sodium antimonate. As a phosphorus compound, phosphate ester, polyphosphoric acid, ammonium polyphosphate, red phosphorus etc. can be mentioned, for example. Examples of other organic flame retardants include nitrogen compounds such as melamine and cyanuric acid. Examples of other inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, silicon compound, boron compound and the like.
[0059]
The polybutylene terephthalate resin of the present invention can be blended with conventional additives as required. There are no particular restrictions on the additives to be added, for example, stabilizers such as antioxidants and heat stabilizers, additives such as lubricants, mold release agents, catalyst deactivators, crystal nucleating agents, and crystallization accelerators are polymerized. It can be added during or after polymerization. Furthermore, in order to impart desired performance to polybutylene terephthalate resin, stabilizers such as UV absorbers and weathering stabilizers, coloring agents such as dyes and pigments, antistatic agents, foaming agents, plasticizers, and impact resistance improvements An agent or the like can be blended.
[0060]
The polybutylene terephthalate resin of the present invention includes, as necessary, thermoplastic resins such as polyethylene, polypropylene, acrylic resin, polycarbonate, polyamide, polyphenylene sulfide resin, polyethylene terephthalate, liquid crystal polyester resin, polyacetal, polyphenylene oxide, and phenol resin. Further, a thermosetting resin such as a melamine resin, a silicone resin, or an epoxy resin can be blended to form a molded product. These thermoplastic resins and thermosetting resins can be used alone or in combination of two or more.
[0061]
There is no particular limitation on the method of blending the above-mentioned various additives into the polybutylene terephthalate resin of the present invention, but blending by melt kneading is preferable, and kneading methods usually used for thermoplastic resins can be applied. . As a kneading method, for example, each component is mixed with a substance as an additional component, if necessary, by a Henschel mixer, a ribbon blender, a V-type blender, etc., and then a single-screw kneading extruder, a multi-screw kneading extruder, It can knead | mix using a roll, a Banbury mixer, a lab plast mill, a Brabender, etc. Each component including the additional components can be supplied to the kneader in a lump or can be supplied sequentially. In addition, two or more kinds of components selected from each component including an additional component may be mixed in advance.
[0062]
There is no particular limitation on the molding method of the polybutylene terephthalate molded product of the present invention, and molding methods generally used for thermoplastic resins, that is, molding methods such as injection molding, hollow molding, extrusion molding, and press molding are applied. be able to.
[0063]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In Examples and Comparative Examples, polybutylene terephthalate oligomers and polybutylene terephthalate resins were evaluated by the following methods.
(1) Reaction time during continuous reaction (average residence time)
A value obtained by dividing the substantial reactant volume by the raw material supply amount q per hour was adopted.
[0064]
(2) Terminal carboxyl group concentration
0.5 g of polybutylene terephthalate resin or oligomer was dissolved in 25 mL of benzyl alcohol and titrated with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide. The smaller the terminal carboxyl group concentration in the polybutylene terephthalate resin, the better the hydrolysis resistance.
[0065]
(3) Terminal vinyl group concentration
A polybutylene terephthalate resin or oligomer was dissolved in hexafluoroisopropanol / deuterated chloroform = 3/7 (v / v), and 1H-NMR at a resonance frequency of 400 MHz was measured and determined. A lower vinyl group concentration indicates that there are few side reactions during the production of the polybutylene terephthalate resin, and at the same time, it is excellent in solid phase polymerization.
[0066]
(4) Terminal glycol group concentration
A polybutylene terephthalate resin or oligomer was dissolved in hexafluoroisopropanol / deuterated chloroform = 3/7 (v / v), and 1H-NMR at a resonance frequency of 400 MHz was measured and determined.
(5) Number average molecular weight of oligomer
Number average molecular weight = 2 / (total end group concentration).
However, total terminal group concentration = terminal carboxyl concentration + terminal glycol concentration + terminal vinyl concentration.
[0067]
(6) Analysis of titanium and tin in polybutylene terephthalate resin
The polybutylene terephthalate resin was wet-decomposed with high-purity sulfuric acid and nitric acid for electronic industry and measured using a high resolution ICP (Induced Coupled Plasma) -MS (Mass Spectrometer) (manufactured by ThermoQuest).
[0068]
(7) Determination of organotitanium compounds
The polybutylene terephthalate resin was dissolved in hexafluoroisopropanol / chloroform = 2/3 (volume ratio) at a concentration of 20 wt%, centrifuged, and the organic titanium compound was precipitated and collected. Finally, hexafluoroisopropanol / chloroform = several times It was washed and collected at 2/3 (volume ratio), dried for 12 hours with a vacuum dryer at 80 ° C., and the weight was determined as the weight ratio relative to the polymer.
[0069]
(8) Organic elemental analysis of organic titanium compounds
About the organic titanium compound acquired by said (5), carbon, hydrogen, and nitrogen were measured using the EA1110 type | mold organic element analyzer by Faisons Co., Ltd. About oxygen, TG-DTA was measured using TG8101D by Rigaku Corporation, and it calculated | required as a weight difference with carbon, hydrogen, and nitrogen calculated | required from the organic elemental analysis.
[0070]
(9) Determination of organotitanium compounds with a particle size of 5 μm or more
A polybutylene terephthalate resin was dissolved in hexafluoroisopropanol / chloroform = 2/3 (volume ratio) at a concentration of 20 wt%, filtered through a polytetrafluoroethylene membrane filter having a pore diameter of 5 μm previously measured, and then with the solvent. After thoroughly washing, the filter was dried in a vacuum dryer at 80 ° C. for 12 hours, and the weight was measured. A value obtained by subtracting the weight of the filter measured in advance from this weight was determined as a weight ratio to the oligomer.
[0071]
(10) X-ray microanalyzer
About the organic titanium compound acquired by said (7), it measured using Shimadzu Corporation EPMA-1600.
(11) X-ray diffraction of organic titanium compounds
The organotitanium compound obtained in (7) above was measured using a RINT 1500 model manufactured by Rigaku Corporation, with a Cu tube, output 40 kV, 250 mA, measurement range 5 to 90 °, and scan speed 4 ° / min.
[0072]
(12) THF concentration in the distillate
Quantified by gas chromatography.
(13) Intrinsic viscosity
Using a mixed solvent of Ubbelohde viscometer and phenol / tetrachloroethane (weight ratio 1/1), at 30 ° C., the polymer solution having a concentration of 1.0 g / dL and the number of drops of the solvent alone were measured. Asked.
[η] = ((1 + 4K_Hηsp)^0.5-1) / (2K_HC)
(However, ηsp = η / η₀−1, η is the number of seconds that the polymer solution falls, η₀Is the number of seconds the solvent falls, C is the polymer solution concentration (g / dL), K_HIs the constant of Haggins. K_HAdopted 0.33.
[0073]
(14) Haze
2.7 g of polybutylene terephthalate resin was dissolved in 20 mL of a phenol / tetrachloroethane mixed solvent (weight ratio 3/2) and filtered using a membrane filter having a pore size of 5 μm. The haze of the filtrate was manufactured by Nippon Denshoku Co., Ltd. It measured with the turbidimeter (NDH-300A).
[0074]
(15) Color tone b value of polybutylene terephthalate resin
A yellow index b value was calculated and evaluated using a color difference meter (Z-300A type) manufactured by Nippon Denshoku Co., Ltd. A lower value indicates less yellowing and a better color tone.
[0075]
(16) Number of foreign matters of 5 μm or more in polybutylene terephthalate resin
10 g of polybutylene terephthalate resin is dissolved in hexafluoroisopropanol / chloroform = 2/3 (volume ratio) at a concentration of 20 wt%, filtered through a polytetrafluoroethylene membrane filter having a pore size of 5 μm, and then thoroughly washed with the solvent. The amount of foreign matter remaining on the filter was observed with an optical microscope, and the number was counted.
[0076]
(17) Amount of tetrahydrofuran (THF) in the resin
5 g of resin pellets were immersed in 10 g of water, treated under pressure at 120 ° C. for 6 hours, and after cooling, the tetrahydrofuran eluted in water was quantified by gas chromatography. The smaller the amount of THF, the less gas is generated from the molded product.
[0077]
(18) Temperature drop crystallization temperature (Tc)
Using a differential scanning calorimeter [Perkin Elmer, Model DSC7], the temperature was raised from room temperature to 300 ° C. at a temperature rising rate of 20 ° C./min, and then the temperature was lowered to 80 ° C. at a temperature falling rate of 20 ° C./min. Was defined as the temperature drop crystallization temperature. The higher the Tc, the faster the crystallization speed and the shorter the molding cycle.
[0078]
(19) Esterification rate of oligomer
It calculated using the acid value and saponification value which were calculated | required as follows.
[Acid value]
The oligomer was dissolved in dimethylformamide and titrated with a 0.1N KOH / methanol solution.
[Saponification value]
The oligomer was hydrolyzed with a 0.5N KOH / ethanol solution and titrated with 0.5N hydrochloric acid.
Esterification rate = (saponification value−acid value) / saponification value) × 100
[0079]
(20) Transesterification rate of oligomer
The remaining methyl ester was quantified using 1H NMR at a resonance frequency of 400 MHz, and calculated using the following formula using the molar concentration of the dicarboxylic acid unit determined by the saponification value.
Transesterification rate = (molar concentration of dicarboxylic acid unit × equivalent of 2-methyl ester) / molar concentration of dicarboxylic acid unit × 2) × 100
[0080]
[Reference example1]
  Connected to the nitrogen line from the upper part of the reflux condenser through a liquid trap, in a glass reaction vessel equipped with an overflow pipe and a screw type stirring blade with an outer diameter of 50 mm in advance at the position of 0.30 L of the actual liquid. A slurry prepared by charging 93% polybutylene terephthalate oligomer and then preparing 1.8 mol of 1,4-butanediol with respect to 1.0 mol of terephthalic acid was supplied at 0.15 L / h. From another supply port of the vessel, while adding tetrabutyl titanate as a titanium amount to 100 ppm per theoretical yield polymer, water and tetrahydrofuran produced at an internal temperature of 230 ° C., a stirring rotational speed of 150 rpm, and atmospheric pressure under nitrogen, Then, 1,4-butanediol was continuously extracted from the upper part of the reflux condenser and subjected to esterification.
[0081]
After 8 hours of stabilization of the system, the indicated value of the torque meter equipped in the stirrer was read, and the rotational stirring power P and the energy Q per unit volume of the reaction liquid were calculated from the following equations.
P = T × ω, Q = P / q
(P: stirring power, T: torque (kg · m), ω: angular velocity (1 / sec), q: raw material supply per unit time (m^Three/ Sec))
[0082]
At this time, the amount of THF distilled out per unit time was 0.15 (mol / charged TPA-mol), and the overflowed oligomer was analyzed in a receiver in a nitrogen atmosphere. Was 96%, the number average molecular weight was 580, the terminal vinyl group concentration was 0.5 μeq / g, and an oligomer having a high esterification rate and a low terminal vinyl concentration was obtained while suppressing the by-production of THF.
[0083]
Next, 150 g of the obtained oligomer was charged into another glass reactor having a vent pipe and a squid type stirring blade and purged with nitrogen, and then the internal temperature was 245 ° C. and the pressure was 2.7 kPa over 10 minutes. The initial polycondensation reaction was performed while extracting water, tetrahydrofuran, and 1,4-butanediol generated in this state from the system. After 2 hours, the pressure was set to 133 Pa over 10 minutes, and the reaction was terminated after 1 hour. The polymer was decompressed with nitrogen and then extracted into a strand from the bottom of the container, and cut into a pellet by cutting with a cutter. The obtained polymer had an intrinsic viscosity of 0.75, a terminal carboxyl group of 12 μeq / g, a b value of 0.4, and a titanium concentration in the pellet of 100 ppm. As shown in Table 1, a polybutylene terephthalate resin excellent in transparency and color tone was obtained.
[0084]
[Reference example2]
  Reference exampleThe butylene terephthalate oligomer having a transesterification rate of 93% was previously filled in the glass reaction vessel used in No. 1, and prepared at a ratio of 1.5 mol of 1,4-butanediol to 1.0 mol of dimethyl terephthalate. The raw material was supplied at 0.15 L / h, and while adding tetrabutyl titanate as a titanium amount to 100 ppm per theoretical yield polymer from another supply port of the container, the internal temperature was 230 ° C. and the stirring rotation speed was 150 rpm. Then, methanol and 1,4-butanediol and tetrahydrofuran are continuously extracted from the top of the reflux condenser at atmospheric pressure under nitrogen,Reference exampleTransesterification was carried out in the same manner as in 1.
[0085]
After 8 hours, the overflowed oligomer was analyzed in a receiver in a nitrogen atmosphere. The transesterification rate was 96%, the number average molecular weight was 600, and the terminal vinyl group concentration was 0.5 μeq / g. While suppressing by-products, an oligomer having a high transesterification rate and a low terminal vinyl concentration was obtained.
[0086]
Next, 150 g of the obtained oligomer was charged into another glass reactor having a vent tube and an iridic stirring blade, followed by nitrogen substitution, and then the internal temperature was 245 ° C. and the pressure was 2.7 kPa over 10 minutes. The initial polycondensation reaction was performed while extracting tetrahydrofuran and 1,4-butanediol produced in this state out of the system. After 2 hours, the pressure was set to 133 Pa over 10 minutes, and the reaction was terminated after 1 hour. The polymer was extracted in the form of a strand from the lower part of the container and cut into a pellet by cutting with a cutter. The obtained polymer had an intrinsic viscosity of 0.75 and a terminal carboxyl group of 15 μeq / g. The analysis results are summarized in Table 1. As shown in Table 1, a polybutylene terephthalate resin excellent in transparency and color tone was obtained.
[0087]
[Reference comparison example1]
  Other than changing the rotation speed of stirring and setting P / q (= Q) to the value shown in Table 1.Reference example1 was performed. The conditions and results are shown in Table 1. The esterification rate of the oligomer was low, and the amount of by-product THF during the oligomerization reaction was large.
[0088]
[Reference comparison example2]
  Other than changing the rotation speed of stirring and setting P / q (= Q) to the value shown in Table 1.Reference exampleSame as 2. The conditions and results are shown in Table 1. The transesterification rate of the oligomer was low.
[0089]
[Example1]
  FIG. 1 shows a flowchart of this embodiment. 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 upper part of the slurry preparation tank 1, 2 is an esterification reaction tank, and 2a is an esterification reaction. Vent port provided in the upper part of the tank 2, 2 b is a catalyst supply port provided in the upper part of the esterification reaction tank 2, 2 c is a sampling port of the esterification reaction tank, 2 d is a rectification tower, 2 e is a distillate Outlet of low boiling point component, 2f is outlet for excess 1,4-butanediol, 2g is supply port for refluxing 1,4-butanediol, 3 is first polycondensation reaction tank, 3a is first polycondensation reaction Vent port provided at the upper part of the tank 3, 4 is a second double condensation reaction tank, 4 a is a vent port provided at the upper part of the second double condensation reaction tank 4, 4 b is the second double condensation reaction tank 4. Catalyst supply port provided at the top, 5 is the third triple condensation reaction tank 5a is a vent port provided at the top of the third triple condensation reaction tank 5, 6 is a polymer extraction die, 7 is a rotary cutter, M1, M2, M3, M4, M5 are stirring devices, G1, G2, G3, G4 and G5 are gear pumps, and P1, P2, P3, P4 and P5 are pipes.
[0090]
An esterification reaction tank 2 was previously filled with a polybutylene terephthalate oligomer having an esterification rate of 93%, and a slurry prepared at a ratio of 1.8 mol of 1,4-butanediol with respect to 1.0 mol of terephthalic acid. From the slurry preparation tank 1 to the esterification reaction tank 2 which is passed through the pipe P1 by the gear pump G1 and has a screw type stirrer, 50 L / h (1.4 × 10^-5  m³/ Sec), and at the same time, tetrabutyl titanate was continuously fed from the catalyst feed port 2b as the amount of titanium to the theoretical yield of 100 ppm per polymer. The esterification reactor 2 is a vertical reactor equipped with a stirring device M2 equipped with a screw type stirring blade having a blade diameter of 160 mm having a vertical rotation axis, and the stirring device M2 has a torque meter for detecting stirring power. Has been. The internal temperature of the esterification reaction tank 2 is 230 ° C., the pressure is 78 kPa, and the generated water, tetrahydrofuran, and unreacted 1,4-butanediol are vent ports 2a connected to a decompressor (not shown). A portion of unreacted 1,4-butanediol is refluxed through 2 g to the first esterification reaction tank 2 through the rectification column (2d), and the remaining 1,4-butanediol is 2f. The low-boiling components mainly consisting of water and tetrahydrofuran were removed from the system through 2e and subjected to esterification reaction. At this time, the amount of 1,4-butanediol returning from 2 g to the esterification reaction vessel is adjusted, and terephthalic acid supplied from P1, 1,4-butanediol supplied from P1, and 1 supplied from 2g. The molar ratio (B / T) of the total 1,4-butanediol of 1,4-butanediol and 1,4-butanediol supplied from 2b is controlled to 2.5, and at the same time, the esterification tank 2 The reaction solution was withdrawn while controlling the liquid level so that the actual solution became 100 L, and continuously supplied to the first polycondensation reaction tank 3. 12 hours after the system was stabilized, the esterification rate of the oligomer collected from the sampling port 2c was 98%, the number average molecular weight was 560, and the terminal vinyl group concentration was 0.5 μeq / g. Moreover, when the amount of THF in the distillate distilled per unit time was analyzed, it was 0.15 (mol / feeding TPA-mol).
[0091]
The first polycondensation reaction tank 3 is also a vertical reaction tank provided with a stirrer M3 having a vertical rotation axis. The internal temperature of the reaction tank 3 is 245 ° C., the pressure is 2.7 kPa, and the actual liquid becomes 100 L. Thus, the initial polycondensation reaction was carried out while extracting the generated water, tetrahydrofuran and 1,4-butanediol from the vent port 3a connected to a decompressor (not shown). The reaction solution was continuously supplied to the second double condensation reaction tank 4.
[0092]
The second double condensation reaction tank 4 is also a vertical reaction tank provided with a stirrer M4 having a vertical rotation axis. The internal temperature of the reaction tank 3 is 240 ° C., the pressure is 200 Pa, and the actual liquid is 100 L. The liquid level is controlled, and the resulting water, tetrahydrofuran, and 1,4-butanediol are further extracted from the vent port 4a connected to a decompressor (not shown), and a polycondensation reaction is further performed. The liquid was continuously supplied to the third triple condensation reaction tank 5.
[0093]
The third triple condensation reaction tank 5 is a horizontal reaction tank having a stirrer M5 having a horizontal rotating shaft having two self-cleaning properties. The internal temperature of the reaction tank 5 is 240 ° C. and the pressure is 200 Pa. The liquid level is controlled so as to be 40 L, and the polycondensation reaction is carried out while extracting the generated water, tetrahydrofuran, and 1,4-butanediol from the vent port 5a connected to a decompressor (not shown). Proceeded. The obtained polymer was continuously extracted in a strand form from the polymer extraction die 6 via the inside of the pipe P5 by the gear pump G5, and was cut by the rotary cutter 7. The obtained polymer had an intrinsic viscosity of 0.85 and a terminal carboxyl group of 12 μeq / g. The analysis values of the pellets are summarized in Table 2. Metal elements other than titanium in the organic titanium compound separated from the pellets were negligible. The X-ray diffraction pattern of the organic titanium compound obtained here is shown in FIG.
[0094]
[Example2]
  Example except that the pressure in the second double condensation reaction tank 4 and the third triple condensation reaction tank 5 was 67 Pa1As well as. The conditions and results are shown in Table 2.
[0095]
[Example3]
  Examples except that tetrabutyl titanate was used as the amount of titanium to give a theoretical yield of 75 ppm per polymer.1As well as. The conditions and results are shown in Table 2.
[0096]
[Example4]
  Example except that the rotation speed of stirring was changed and P / q (= Q) was set to the value shown in Table 2.1As well as. The conditions and results are shown in Table 2.
[0097]
[Example5]
  Example except that the rotation speed of stirring was changed and P / q (= Q) was set to the value shown in Table 2.1As well as. The conditions and results are shown in Table 2.
[0098]
[Example6]
  Other than changing the rotation speed of stirring and continuously supplying the raw material at 70 L / h (1.9 × 10 −5 m 3 / sec) and setting P / q (= Q) to the value shown in Table 2. Example1As well as.
[0099]
[Example7]
  Other than changing the rotation speed of stirring and continuously supplying the raw material at 25 L / h (6.9 × 10 −6 m 3 / sec) and setting P / q (= Q) to the value shown in Table 2. Example1As well as. The conditions and results are shown in Table 2.
[0100]
[Example8]
  Example except that tetrabutyl titanate was used as a catalyst as a titanium amount and theoretical yield was 85 ppm per polymer and butylhydroxytin oxide was added as a tin amount at 125 ppm and an esterification reaction was carried out at a reaction pressure of 40 kPa.7As well as. The conditions and results are shown in Table 3.
[0101]
[Example9]
  Example except that the esterification reaction was performed at a reaction temperature of 235 ° C. and a reaction pressure of 100 kPa.1As well as. The conditions and results are shown in Table 3.
[0102]
[Example10]
  Example except that tetrabutyl titanate was used as the amount of titanium and the theoretical yield was 35 ppm per polymer.1As well as. The conditions and results are shown in Table 3. In particular, a polybutylene terephthalate resin having good transparency and few foreign matters was obtained.
[0103]
[Example11]
  Examples except that tetrabutyl titanate was used as the amount of titanium to give a theoretical yield of 50 ppm per polymer.1As well as. The conditions and results are shown in Table 3. In particular, a polybutylene terephthalate resin having good transparency and few foreign matters was obtained.
[0104]
[Example12]
  Example except that B / T was set to 3.01As well as. The conditions and results are shown in Table 3. In particular, a polybutylene terephthalate resin with little foreign matter was obtained.
[0105]
[Example13]
  Example except that the rotation speed of stirring was changed and P / q (= Q) became the value shown in Table 31As well as. The conditions and results are shown in Table 3.
[Comparative example1]
  Example except that the rotation speed of stirring was changed and P / q (= Q) was set to the value shown in Table 41As well as. The conditions and results are shown in Table 4. The esterification rate of the oligomer was low, and the amount of by-product THF during the oligomerization reaction was large.
Also, the amount of foreign matter in the polybutylene terephthalate resin was large.
[0106]
[Comparative example2]
  Example except that the rotation speed of stirring was changed and P / q (= Q) was set to the value shown in Table 46As well as. The conditions and results are shown in Table 4. The esterification rate of the oligomer was low, and the amount of by-product THF during the oligomerization reaction was large. Also, the amount of foreign matter in the polybutylene terephthalate resin was large.
[0107]
[Comparative example3]
  As a catalyst, tetrabutyl titanate was added as titanium, and the theoretical yield was 55 ppm per polymer, and butylhydroxytin oxide was added as 285 ppm as tin. The stirring speed was changed, and P / q (= Q) was adjusted to the value shown in Table 4. Other examples8As well as. The conditions and results are shown in Table 4. This comparative example is an example in which the amount of organic titanium is suppressed and the organic tin compound is supplemented in a relatively large amount according to the method of JP-A-10-330469, but the b value is high and the amount of foreign matter in the polybutylene terephthalate resin. There were also many.
[0108]
[Comparative example4]
  Examples except that the amount of tetrabutyl titanate added was 320 ppm as the amount of titanium, the reaction temperature was 240 ° C., the pressure was 44 kPa, the rotation speed of stirring and the P / q (= Q) were the values shown in Table 4.6As well as. The conditions and results are shown in Table 4. The vinyl group concentrations of the oligomer and polymer were high, and both haze and foreign matter amount were high.
[0109]
[Comparative example5]
  Example except that the rotation speed of stirring was changed and P / q (= Q) was set to the value shown in Table 41As well as. The conditions and results are shown in Table 4. In the obtained polymer, the content of organic titanium was high, and not only the haze was high, but also the amount of THF produced by the side reaction was large.
[0110]
[Comparative example6]
  Example except that raw material was continuously supplied at 140 L / h and P / q (= Q) was set to the value shown in Table 41As well as. The conditions and results are shown in Table 4. In the obtained polymer, the content of organic titanium was high, and not only the haze was high, but also the amount of THF produced by the side reaction was large.
[0111]
[Reference example 3]
  1.78 mol of terephthalic acid (TPA), 3.21 mol of 1,4-butanediol (B / T = 1.8), 8.2 × 10 -4 mol of tetrabutyl titanate (theoretical yield of 100 ppm per polymer as titanium content) Was charged into a glass reaction vessel equipped with a screw type stirring blade having an outer diameter of 50 mm and sufficiently substituted with nitrogen. Subsequently, the temperature of the system was raised and the actual liquid amount was measured and found to be 500 mL. The stirring speed was 180 rpm, and after 60 minutes, the temperature reached 210 ° C. and the pressure reached 80 kPa, and the generated water, THF, and excess 1,4-butanediol were distilled out of the system for 2.0 hours. (The reaction start time is the time when a predetermined temperature and a predetermined pressure are reached). At this point, a part of the sample was taken and the esterification rate was measured and found to be 99%. The rotational stirring power P and the stirring energy Q per unit volume were converted from the indicated values of a torque meter equipped in the stirrer by the following formulas.
  P = T × ω, Q = P × t / V
  (P: stirring power, T: torque, ω: angular velocity, t: reaction time, V: reactant volume)
[0112]
150 g of the oligomer thus obtained was charged into another glass reactor having a vent pipe and a squid type stirring blade and purged with nitrogen, and then reached to a temperature of 245 ° C. and a pressure of 133 Pa over 60 minutes. The polycondensation reaction was carried out for 1.5 hours. After completion of the reaction, the polymer was extracted in the form of a strand, cut into a pellet, and provided for analysis. The obtained polymer had an intrinsic viscosity of 0.75 and a terminal carboxyl group of 8 μeq / g. The organotitanium compound was separated and quantified from the pellet by the method described above. Analysis with an X-ray microanalyzer revealed that the spectrum of metal elements other than titanium was negligible. When X-ray diffraction of this compound was performed, the peak pattern shown in FIG. 2 was shown, and it was found that the compound had a specific crystal structure. On the other hand, the composition of this organotitanium compound was Ti / C / H / O = 1.0 / 5.0 / 4.0 / 3.3 from the results of X-ray microanalyzer, elemental analysis, and TG-DTA. It was. The haze value of the polybutylene terephthalate resin determined by the above method was 1.2, and a polybutylene terephthalate resin excellent in transparency was obtained. These analytical values are summarized in Table 5.
[0113]
[Reference example 4]
  1.64 mol of dimethyl terephthalate (DMT), 1.97 mol of 1,4-butanediol (B / T = 1.2), 7.6 × 10 −4 mol of tetrabutyl titanate (theoretical yield per polymer as the amount of titanium) 100 ppm) was charged into a glass reaction vessel equipped with a screw type stirring blade having an outer diameter of 50 mm and sufficiently substituted with nitrogen. Subsequently, the system is immersed in an oil bath, the temperature is raised, the rotation speed of stirring is 180 rpm, and after 60 minutes, the generated methanol, 1,4-butanediol, and THF are distilled out of the system at a temperature of 210 ° C. and atmospheric pressure under nitrogen. The reaction was carried out for 2 hours (the reaction start time was the time when a predetermined temperature and a predetermined pressure were reached). At this point, a part of the sample was taken and the transesterification rate was measured and found to be 90%.
[0114]
150 g of the oligomer thus obtained was charged into another glass reactor having a vent pipe and a squid type stirring blade and purged with nitrogen, and then reached to a temperature of 245 ° C. and a pressure of 133 Pa over 60 minutes. The polycondensation reaction was carried out for 1.5 hours. After completion of the reaction, the polymer was extracted in the form of a strand, cut into a pellet, and provided for analysis. The analysis values are summarized in Table 1. The organotitanium compound was separated and quantified from the pellet by the method described above. Analysis with an X-ray microanalyzer revealed that the spectrum of metal elements other than titanium was negligible. When the X-ray diffraction of this compound was implemented, the same peak pattern as FIG. 2 was shown. From the results of X-ray microanalyzer, elemental analysis, and TG-DTA, the composition of the organotitanium compound was Ti / C / H / O = 1.0 / 5.0 / 4.0 / 3.5. These analytical values are summarized in Table 5.
[0115]
[Reference Comparative Example 3]
  Other than changing the rotation speed of stirring and setting Q to the value shown in Table 5.Reference example 3As well as. The analysis values are summarized in Table 5. The obtained polymer had a high organic titanium content and a high haze.
[0116]
[Table 1]
[0117]
[Table 2]
[0118]
[Table 3]
[0119]
[Table 4]
[0120]
[Table 5]
[0121]
【The invention's effect】
The polybutylene terephthalate resin composition of the present invention is excellent in mechanical strength and color tone, has not only reduced haze and foreign matter, but also has a short injection molding cycle, excellent productivity, and high stability to hydrolysis. Since there is little generation | occurrence | production of gas from, since it can use suitably for a film, a monofilament, a fiber, an injection molded part etc., industrial utility value is large. Moreover, in the manufacturing method of the polybutylene terephthalate of this invention, a side reaction is suppressed and the quality fall by the substance derived from a catalyst deactivation or a catalyst deactivation component can be suppressed.
[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.
2 is a chart showing an X-ray diffraction pattern of an organic titanium compound obtained in Example 16. FIG.
[Explanation of symbols]
1 Slurry preparation tank
1a, 1b Raw material supply port
2 Esterification reaction tank
2a Vent port
2b Catalyst supply port
2c Sampling port
2d rectifying tower
2e Low boiling point component outlet in distillate
2f Excess 1,4-butanediol outlet
2 g reflux 1,4-butanediol supply port
3 First polycondensation reactor
3a Vent port
4 Second double condensation reactor
4a Vent port
5 Triple condensation reactor
5a Vent port
6 Polymer extraction die
7 Pelletizer
M1, M2, M3, M4, M5 Stirrer
G1, G2, G3, G4, G5 Gear Bump
P1, P2, P3, P4, P5 piping

Claims (6)

A dicarboxylic acid component mainly composed of terephthalic acid or a dialkyl ester thereof and a diol component mainly composed of 1,4-butanediol are continuously esterified or transesterified in the presence of a catalyst, and then polycondensed. In the method for producing polybutylene terephthalate, the stirring energy Q (kJ / m ³ ) per unit volume of the reactant added to the reactant in the esterification reaction step or transesterification reaction step is expressed by the following formula (1): meet the relationship, and terephthalic acid or dialkyl terephthalate of raw material supplied to the esterification reaction vessel or the transesterification reaction vessel per unit time, the molar ratio of the formula and 1,4-butanediol (2 method for producing a polybutylene terephthalate resin), characterized in Succoth meet.
Q ≧ 1500 kJ / m ³ (1)
B / T = 2.5-4.5 (mol / mol) (2)
(However, B is the number of moles of 1,4-butanediol supplied from the outside to the esterification or transesterification reaction tank per unit time, and T is supplied from the outside to the esterification or transesterification reaction tank per unit time. The number of moles of terephthalic acid or terephthalic acid dialkyl ester) The method for producing a polybutylene terephthalate resin according to claim 1 , wherein the catalyst for the esterification reaction or the transesterification reaction contains at least a titanium compound. The method for producing a polybutylene terephthalate resin according to claim 1 or 2 , wherein a titanium compound is used as a catalyst in an amount of 1 to 150 ppm as a titanium atom with respect to the obtained polybutylene terephthalate resin. Esterification reaction or transesterification reaction temperature is 200-240 degreeC, The manufacturing method of the polybutylene terephthalate resin in any one of Claims 1-3 characterized by the above-mentioned. The method for producing a polybutylene terephthalate resin according to any one of claims 1 to 4 , wherein the pressure in the esterification reaction or transesterification reaction step is 10 kPa to 130 kPa in absolute pressure. The method for producing a polybutylene terephthalate resin according to any one of claims 1 to 5 , wherein an average residence time in the esterification reaction or transesterification reaction step is 0.5 to 5 hours.