JP2005170989A - Manufacturing method of polytrimethylene terephthalate resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polytrimethylene terephthalate resin which is decreased in the content of the cyclic dimer produced in the polymerization step and excellent in moldability and whose molded body has excellent coatability and adhesion for a coating material or a paste agent. <P>SOLUTION: The manufacturing method of the polytrimethylene terephthalate resin comprises treating the resin whose repeating units are constituted of trimethylene terephthalate repeating units in a proportion of &ge;80 mol% and whose limiting viscosity is &ge;0.5 dl/g, by a cyclic dimer removing apparatus that satisfies the following conditions (a)-(d): (a) to treat at a temperature of the melting point of the resin or higher and under a reduced pressure of &le;3.0 kPa; (b) to form, in the cyclic dimer removing apparatus, a thin film of the molten resin which takes a value of &ge;1.0 cm<SP>2</SP>/g, value obtained by dividing the resin-gas phase contacting area by the resin weight; (c) the filling ratio of the molten resin occupying in the vacancy inside the cyclic dimer removing apparatus is &le;40%; and (d) the cyclic dimer content after the treatment is decreased by 0.2 wt% or more against that of the resin before the treatment. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a method for producing a polytrimethylene terephthalate resin. More specifically, by reducing the content of oligomers produced in the polymerization process, particularly cyclic dimers, the moldability is excellent, and the molded body is characterized by excellent paint and paste applicability and adhesiveness. The present invention relates to a method for producing a polytrimethylene terephthalate resin at low cost.

  Polyesters, particularly polyethylene terephthalate resins, have excellent physical and chemical properties and are widely used as fibers, films, and other molded articles, but lack flexibility. On the other hand, it is synthesized by melt polymerization of terephthalic acid or a lower alcohol ester of terephthalic acid and 1,3-propanediol (also called trimethylene glycol), or by further solid-phase polymerization of a prepolymer obtained by once melt polymerization. Polytrimethylene terephthalate resin is a material with excellent flexibility, and its glass transition temperature and melting point are close to those of nylon 6 and has little effect on physical properties due to moisture absorption. It has features.

  However, it has been found that the polytrimethylene terephthalate resin generates an oligomer in the polymerization process, and the oligomer causes various problems in the spinning process, the molding process, and the post-processing process. For example, in the spinning process, if spinning is performed for a long time, oligomers sublimate and precipitate around the spinneret, which adheres to the fibers and causes yarn breakage and fluff. In the molding process, it adheres to the molding die and causes the appearance and dimensional accuracy of the molded body to be impaired. In addition, the oligomer may bleed out on the surface of the molded body after being molded into fibers, films, resin parts, etc., and depending on the post-processing conditions, the applicability and adhesion of paints and pastes may be impaired. .

  The oligomer in the polytrimethylene terephthalate resin produced by melt polymerization is contained in an amount of about 2.5 to 3.5% by weight based on the resin. About 90% by weight of the oligomer is a cyclic dimer. It has long been known that such an oligomer also exists in a polyethylene terephthalate resin having a similar skeleton. However, in the case of a polyethylene terephthalate resin, its abundance is about 1% by weight. Furthermore, since this oligomer is mostly a cyclic trimer and has a large molecular weight, sublimation and bleed-out are relatively difficult to occur. Therefore, the degree of problem is more serious with polytrimethylene terephthalate resin.

  Attempts to reduce the oligomers contained in the polytrimethylene terephthalate resin are already known, and the most effective method is solid-phase polymerization (see, for example, Patent Documents 1 to 3). However, in the solid phase polymerization, it is necessary to form a polymer having a low polymerization degree into a pellet shape, perform a crystallization treatment so as not to be thermally fused at the time of solid phase polymerization, and then perform polymerization for a long time. This complicates the process, lowers productivity, and increases manufacturing costs. In solid-phase polymerization, the polymerization proceeds while releasing the trimethylene glycol generated by the polymerization reaction from the surface of the pellet, so the degree of polymerization differs greatly depending on the size and shape of the pellet and the inner and outer layers of the pellet. The degree of variation increases. Furthermore, when solid phase polymerization is performed, solid polymers rub against each other for a long time, so that a large amount of powdery polymer is generated and loss occurs. The powdered polymer may cause yarn breakage and fluff at the time of spinning, and there is a problem that it is necessary to add an additional process to remove it. Furthermore, the reduction of the cyclic dimer content by solid phase polymerization is limited to about 1% by weight due to the ring chain equilibrium. To reduce the cyclic dimer, more complicated and expensive processes such as washing and extraction are added. There was no way to do it.

On the other hand, in melt polymerization, which is more advantageous in terms of productivity and manufacturing cost, the processing temperature is higher, so the chain equilibrium moves to the cyclic dimer side, and the cyclic dimer content is about 2.5% by weight. Improvements have been considered more difficult because they are larger than polymerization.
JP-A-8-311177 Special Table 2000-502392 Korean Published Patent No. 1998-0661618

  The problem of the present invention is to solve the above problems and reduce the content of oligomers produced in the polymerization process, particularly cyclic dimers, thereby improving the moldability, and the paint of the molded body, the applicability of the paste, An object of the present invention is to provide a method for producing a polytrimethylene terephthalate resin, which is excellent in adhesiveness, at a low cost.

In order to solve this problem, the present inventors have analyzed in detail the characteristics of the cyclic dimer and the process for producing the same, and as a result, the chain chain equilibrium is more disadvantageous than solid-phase polymerization, although the conditions are above the melting temperature. The removal rate of the cyclic dimer by forming a molten resin thin film having a value obtained by dividing the area where the resin is in contact with the gas phase by the weight of the resin is 1 cm ² / g or more and adjusting the conditions such as the degree of vacuum. It is possible to dramatically increase In addition, by processing polytrimethylene terephthalate resin with a specific degree of polymerization, we found that there are conditions where the removal rate of cyclic dimer exceeds the formation rate of cyclic dimer, and the present invention was achieved by combining these technologies. did.

That is, the present invention
(1) Polytrimethylene terephthalate resin having an intrinsic viscosity of 0.5 dl / g or more, in which 80 mol% or more of repeating units are composed of repeating units of trimethylene terephthalate, is represented by the following (a), (b), (c) , A process for producing a polytrimethylene terephthalate resin with reduced cyclic dimer content, characterized in that the treatment is performed with a cyclic dimer removing device that satisfies the condition of (d),
(A) Treatment at a temperature equal to or higher than the melting point of the resin under a reduced pressure condition of 3.0 kPa or less.
(B) In the cyclic dimer removing apparatus, a molten resin thin film having a value obtained by dividing the area where the resin is in contact with the gas phase by the resin weight is 1.0 cm ² / g or more.

(C) The filling rate of the molten resin in the void volume in the annular dimer removing device is 40% or less.
(D) The cyclic dimer content after the treatment is reduced by 0.2% by weight or more with respect to the cyclic dimer content of the resin before the treatment.

(2) The molten resin thin film is formed on the inner wall of the apparatus with a spatula and a screw installed in the annular dimer removing apparatus, and the surface of the molten resin thin film is renewed. A process for producing a polytrimethylene terephthalate resin,
(3) The polytrimethylene terephthalate resin before treatment is continuously supplied to the cyclic dimer removing device, and at the same time, the resin after treatment is continuously extracted. The present invention relates to a method for producing trimethylene terephthalate resin.

  The pre-treatment polytrimethylene terephthalate resin used in the present invention is a polytrimethylene terephthalate resin having an intrinsic viscosity of 0.5 dl / g or more in which 80% by weight or more of repeating units are composed of trimethylene terephthalate units. In order to suppress the terminal hydroxyl group concentration of the polymer, the intrinsic viscosity is 0.5 dl / g or more, and in order to suppress the melt viscosity, the intrinsic viscosity is 3 dl / g or less, preferably 0.7 to 2.5 dl / g, particularly preferably. Is 0.8 to 2.3 dl / g, most preferably 0.85 to 2.0 dl / g.

  As a raw material monomer that forms the main skeleton of the polytrimethylene terephthalate resin of the present invention, in addition to terephthalic acid and 1,3-propanediol, other monomers may be copolymerized at less than 20% by weight of the repeating units. The monomer to be copolymerized is not particularly limited, such as diol, dicarboxylic acid, dicarboxylic acid ester, dicarboxylic acid amide, and oxycarboxylic acid. Specific examples include diols such as ethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, oxalic acid, and malon. Acid, succinic acid, glutaric acid, adipic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 2-sodium Sulfoisophthalic acid, 2-potassium sulfoisophthalic acid, 2-lithium sulfoisophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, 2-sodium sulfo-4-hydroxybenzoic acid, tetrabutylphosphonium 5-sulfoisophthalate Dicarboxylic acid such as Even lower alcohol esters such as methanol, oxycarboxylic acids such as oxyacetic acid and oxybenzoic acid and lower alcohol esters such as methanol, and polyols such as polyethylene glycol and polytetramethylene glycol having a molecular weight of 200 to 100,000. Good. Further, if necessary, two or more kinds of ester-forming monomers may be copolymerized.

  Further, a copolymer component generated in the polymerization process, for example, a dimer (bis (3-hydroxypropyl) ether) of 1,3-propanediol may be copolymerized. Bis (3-hydroxypropyl) ether is produced by reacting 1,3-propanediol and the 3-hydroxypropyl group at the polymer molecule end with 1,3-propanediol during the polymerization process, and directly into polytrimethylene terephthalate. Copolymerization reduces the light resistance and heat resistance of polytrimethylene terephthalate, but when moderately copolymerized, it also has the effect of increasing the dye exhaust rate and spinning stability of the fiber. Therefore, it is preferable that bis (3-hydroxypropyl) ether is appropriately copolymerized, and the copolymerization ratio is 0.01 to 2% by weight, preferably 0.04 to 1.2% by weight.

  The pre-treatment polytrimethylene terephthalate resin used in the present invention can be produced by either melt polymerization or solid phase polymerization. From the viewpoint of cost, melt polymerization is preferable, and more preferably, the cyclic dimer removal device is installed after the melt polymerization equipment for polytrimethylene terephthalate resin, and the resin is continuously supplied to the device, and at the same time, the cyclic dimer content is reduced. In this method, the treated resin is continuously extracted.

  The pre-treatment polytrimethylene terephthalate resin used in the present invention is prepared in advance using a polymerization catalyst such as 2-ethylhexanoate, which has a relatively low rate of formation of cyclic dimers, Reduce the rate of cyclic dimer formation by methods such as deactivating the polymerization catalyst residue by contacting with phosphoric acid, etc., or reacting phthalic anhydride as a terminal hydroxyl group blocking agent in advance with the resin before treatment. It is possible, and after performing these methods, if the cyclic dimer removal device of the present invention is used, the cyclic dimer content of the polytrimethylene terephthalate resin after the treatment can be further easily reduced, and at the time of melt molding Since the production | generation of a cyclic | annular dimer is also suppressed, since the molded object of much lower cyclic | annular dimer content can be manufactured, it is preferable. For the same purpose, a method of deactivating the polymerization catalyst residue by contacting water vapor, phosphoric acid or the like with the resin treated with the cyclic dimer removing apparatus of the present invention, or as a terminal hydroxyl group blocking agent in the treated resin A method of reacting phthalic anhydride or the like is also possible.

In addition, in the polytrimethylene terephthalate resin before treatment used in the present invention, at least one gas such as nitrogen or carbon dioxide, or one or more volatile substances such as water or 1,3-propanediol is added in an amount of 0.0001 to 10% by weight. The method of treating with the cyclic dimer removing apparatus of the present invention after containing in the range of% by weight is preferable because the removal efficiency of the cyclic dimer can be improved by the entrainment effect and the effect of reducing the partial pressure of the cyclic dimer.
The cyclic dimer removing apparatus of the present invention is characterized in that the following conditions (a), (b), (c), and (d) are satisfied.

(A) The treatment is performed under a reduced pressure condition of 3.0 kPa or less at a temperature not lower than the melting point of the resin.
The temperature is equal to or higher than the melting point of the resin in order to prevent the polytrimethylene terephthalate resin from solidifying in the cyclic dimer removing apparatus and increase the removal rate of the cyclic dimer. In order to increase the removal rate of the cyclic dimer, it is preferable to perform the treatment at a higher temperature, but there is an upper limit temperature in order to suppress a decrease in molecular weight, decomposition, coloring, and the like of the resin. The temperature at which the cyclic dimer can be efficiently removed is in the range of 230 ° C to 330 ° C. More preferably, it is the range of 240 degreeC-310 degreeC, More preferably, it is the range of 245 degreeC-290 degreeC, Most preferably, it is the range of 250 degreeC-270 degreeC. As a means to satisfy the improvement of the removal rate of the cyclic dimer and the reduction of the molecular weight of the resin and the suppression of side reactions at the same time, the cyclic dimer removing apparatus was adjusted to a plurality of temperatures, and the cyclic dimer was removed in the high temperature compartment. After that, when the resin is moved to a low-temperature compartment, the resin temperature is quickly lowered, and the resin is sheared by a method such as a molecular weight reduction or side reaction suppression, or a spatula or a screw installed in the cyclic dimer removal device. At the same time, a method of suppressing the decrease in the molecular weight of the resin and side reactions by quickly removing heat with the cyclic dimer removing apparatus main body set at a relatively low temperature is preferably used.

The degree of vacuum when removing the cyclic dimer is 3.0 kPa or less. The degree of vacuum increases the removal rate of the cyclic dimer, reduces the processing time for reducing the cyclic dimer content, prevents side reactions such as resin molecular weight reduction, decomposition, and coloring, and sufficiently reduces the cyclic dimer content. It is determined as appropriate. More preferably, it is 2.0 kPa or less, More preferably, it is 1.0 kPa or less, Most preferably, it is 0.5 kPa or less, Most especially, it is 0.2 kPa or less.
(B) In the cyclic dimer removing apparatus, a molten resin thin film having a value obtained by dividing the area where the resin is in contact with the gas phase by the resin weight is 1.0 cm ² / g or more is formed.
In the cyclic dimer removing apparatus of the present invention, the value obtained by dividing the area where the resin is in contact with the gas phase by the weight of the resin needs to be 1.0 cm ² / g or more. This value increases the removal rate of the cyclic dimer, reduces the processing time for reducing the cyclic dimer content, prevents side reactions such as resin molecular weight reduction, decomposition, and coloring, and reduces the cyclic dimer content by 1.0 cm. ² / g or more. More preferably, it is 1.5 cm ² / g or more, more preferably 2.0 cm ² / g or more, most preferably 2.5 cm ² / g or more, and most preferably 3.0 cm ² / g. That's it.

  There is no particular limitation on the method for forming the molten resin thin film in the annular dimer removing apparatus, and there is a method for discharging the molten resin into a thin film or thread form from the slit-like holes and discharging the molten resin introduced into the apparatus. A method of forming a thin film on a support by dropping it along the support, a method of adding a molten resin on a rotating disk installed in the apparatus, and forming a thin film on the disk by centrifugal force. Examples include a method of forming a molten resin thin film on the inner wall of the apparatus with equipment such as a spatula and a screw installed, and updating the surface of the molten resin thin film. Among the above, the method of forming a molten resin thin film on the inner wall of the apparatus with equipment such as a spatula or a screw installed in the apparatus can remove the cyclic dimer with high efficiency by renewing the surface, and the temperature control of the resin is easy To preferred.

(C) The filling rate of the molten resin occupying the void volume in the cyclic dimer removing device is 40% or less.
The cyclic dimer removing device of the present invention needs to have a molten resin filling rate of 40% or less in the void volume in the device. The molten resin introduced into the apparatus is prevented from foaming under reduced pressure, a uniform molten resin thin film is formed to collect in a lump, and the partial pressure of the cyclic dimer in the gas phase increases, so the removal rate is increased. This is to prevent a decrease, to reduce the processing time for reducing the cyclic dimer content, to prevent side reactions such as a decrease in molecular weight, decomposition, and coloring of the resin, and to reduce the cyclic dimer content. The filling rate is more preferably 30% or less, still more preferably 20% or less, most preferably 15% or less, and most preferably 10% or less.

(D) The cyclic dimer content after the treatment is reduced by 0.2% by weight or more with respect to the cyclic dimer content of the resin before the treatment.
The cyclic dimer removal apparatus of the present invention requires that the cyclic dimer content after the treatment is reduced by 0.2% by weight or more with respect to the cyclic dimer content of the resin before the treatment. This is to sufficiently improve the moldability of the obtained polytrimethylene terephthalate resin, the coating property of the molded body, the applicability of the paste, and the degree of improvement in adhesion.
The treatment time of the polytrimethylene terephthalate resin using the cyclic dimer removing apparatus of the present invention requires 1 minute or more. When the treatment is performed for more than 1 minute, the treatment time is not limited, but if the treatment time is too long, side reactions such as a decrease in molecular weight of the resin, decomposition, and coloring may be caused. The preferred treatment time is in the range of 1 minute to 120 minutes, more preferably in the range of 1 minute to 60 minutes, most preferably in the range of 1 minute to 20 minutes, and most particularly preferably 1 minute or more. The range is 10 minutes or less.

  The form of the cyclic dimer removal apparatus is a void volume that satisfies the above conditions, equipment that ensures the area where the resin contacts the gas phase, temperature control equipment, pressure control equipment, recovered cyclic dimer recovery equipment, and introduction of polytrimethylene terephthalate resin -There is no particular limitation as long as it is a device equipped with a discharge facility. For example, a support having a wire-like, net-like, plate-like, or porous plate-like structure for the purpose of expanding the area where the resin is in contact with the gas phase, on the inner or inner wall of the annular dimer removing device whose temperature and vacuum degree are adjusted An annular dimer removal device with a body installed. It is possible to form a molten resin thin film on the inner wall of the device and to update the surface of the molten resin thin film by equipment such as a spatula and a screw installed inside the annular dimer removing device whose temperature and degree of vacuum are adjusted. An annular dimer removal device. In addition, commercially available kneaders with vacuum vents, extruders with vacuum vents, thin film evaporators, etc. also satisfy the above conditions of temperature, degree of vacuum, molten resin thin film, filling rate in the void volume in the device. If you can drive, you can use it.

In addition, a method of directly introducing a gas such as nitrogen or carbon dioxide or a volatile substance such as water or 1,3-propanediol into the inside of the cyclic dimer removing apparatus also reduces the partial pressure of the cyclic dimer in the apparatus. Thus, the cyclic dimer can be removed more efficiently, which is preferable.
Hereinafter, a suitable example is given and demonstrated about the manufacturing method of the polytrimethylene terephthalate resin of this invention.
The polytrimethylene terephthalate resin of the present invention is a polytrimethylene terephthalate resin having an intrinsic viscosity of 0.5 dl / g or more, wherein 80% by weight or more of repeating units are composed of trimethylene terephthalate units, obtained by melt polymerization with addition of a catalyst. It is.

Melt polymerization is a method in which 1,3-propanediol of terephthalic acid and / or its oligomer is produced by reacting terephthalic acid and / or its lower alcohol ester with 1,3-propanediol and then polycondensing it. is there. The terephthalic acid, lower alcohol ester of terephthalic acid, and 1,3-propanediol used in the present invention may be commercially available, or those recovered from polytrimethylene terephthalate or polytrimethylene terephthalate products, and preferably have a purity of 95% More preferably, it is 98% or more.
The charging ratio of 1,3-propanediol to terephthalic acid as a polymerization raw material or lower alcohol ester of terephthalic acid is preferably 0.8 to 3 in terms of molar ratio. When the feed ratio is less than 0.8, the transesterification reaction does not proceed easily. When the feed ratio is greater than 3, the melting point is lowered and the whiteness of the obtained polymer tends to decrease. Preferably, it is 1.4-2.5, More preferably, it is 1.5-2.3.

  The catalyst is necessary to facilitate the reaction. For example, titanium tetrabutoxide, titanium alkoxide represented by titanium tetraisopropoxide, amorphous titanium oxide precipitate, amorphous titanium oxide / silica coprecipitation , Metal oxides such as amorphous zirconia precipitates, metal carboxylates such as calcium acetate, manganese acetate, cobalt acetate, antimony acetate, tin 2-ethylhexanoate, etc. with respect to the total carboxylic acid component monomers. It is preferable to use 01 to 0.2% by weight, preferably 0.05 to 0.12% by weight because of the combination of reaction rate, polymer whiteness, and thermal stability.

The reaction temperature is about 200 ° C. to 250 ° C., and the reaction can be carried out while distilling off by-produced alcohol such as water and methanol. The reaction time is usually 2 to 10 hours, preferably 2 to 4 hours. The reaction product thus obtained is 1,3-propanediol ester of terephthalic acid and / or its oligomer.
The above esterification reaction and transesterification reaction may be carried out successively in succession in two or more reaction kettles as required.
The polytrimethylene terephthalate resin can be produced by further polycondensing the 1,3-propanediol ester of terephthalic acid thus obtained and / or its oligomer.

  In the polycondensation reaction, titanium tetrabutoxide, titanium alkoxide represented by titanium tetraisopropoxide, amorphous titanium oxide precipitate, amorphous titanium oxide / silica coprecipitate, amorphous as required Metal oxides such as zirconia precipitates, metal carboxylates such as tin 2-ethylhexanoate and the like are 0.01 to 0.2% by weight, preferably 0.03 to 0.15% based on the total carboxylic acid component monomers. Add weight percent. As this polycondensation catalyst, the catalyst used in the esterification reaction or transesterification reaction can be used as it is, or it may be newly added. Of these catalysts, titanium-based and tin-based catalysts are effective for all esterification, transesterification, and polycondensation reactions. It is the most preferable catalyst in that the polycondensation reaction can be carried out with a small amount without adding it before the condensation reaction or even when it is added. Polytrimethylene terephthalate resin produced by a tin-based catalyst typified by tin 2-ethylhexanoate has a lower cyclic dimer formation rate than a titanium-based catalyst. It is preferable because it improves further.

In the polycondensation reaction, polycondensation can be performed under reduced pressure in order to efficiently discharge 1,3-propanediol and further water and alcohol remaining in the reaction system produced by the esterification reaction or transesterification reaction. Preferably, the degree of vacuum to be applied is 0.0001 to 2 torr, preferably 0.01 to 0.7 torr.
The intrinsic viscosity by melt polymerization is 0.5 dl / g or more, preferably 0.75 dl / g or more, particularly preferably 0.8 dl / g or more, most preferably 0.85 dl / g or more, and most preferably 1.0 dl / g. There are no particular limitations on the polymerization equipment for producing the pre-treatment polytrimethylene terephthalate resin used in the present invention that is greater than or equal to g, and a tank-type polymerizer equipped with a stirrer, and disc ring as a final reactor in the polycondensation step Examples of the method for producing a polymer having a higher degree of polymerization, good heat stability and color tone, and a prepolymer of polytrimethylene terephthalate resin in a molten state include equipment having a reactor or a cage type reactor installed. In particular, the equipment for polymerizing under reduced pressure while being dropped along the support after being discharged from the holes of the perforated plate It can be preferably used.

A polytrimethylene terephthalate resin having an intrinsic viscosity of 0.5 dl / g or more can be produced only by melt polymerization. It is also possible to produce a resin.
When copolymerizing polytrimethylene terephthalate, a comonomer can be added at any stage of the esterification reaction, transesterification reaction, and polycondensation reaction.
The polytrimethylene terephthalate resin having an intrinsic viscosity of 0.5 dl / g or more thus obtained can be once formed into chips and then introduced into the cyclic dimer removing apparatus of the present invention for processing. From the viewpoint of quality, more preferably, the cyclic dimer removing device of the present invention is installed after the melt polymerization facility for producing polytrimethylene terephthalate resin having an intrinsic viscosity of 0.5 dl / g or more, and the resin is continuously fed into the device. At the same time, the resin after treatment is continuously extracted with reduced cyclic dimer content.

It is also possible to introduce the pre-treatment polytrimethylene terephthalate resin used in the present invention into the cyclic dimer removing apparatus of the present invention after performing an operation for reducing the activity of the catalyst residue contained in the resin in advance. Since the rate of cyclic dimer formation is reduced by reducing the activity of the residue, this is preferable because the effects of the invention are further improved.
The method for reducing the activity of the catalyst residue contained in the polytrimethylene terephthalate resin before the treatment used in the present invention is not particularly limited, but a specific method includes, for example, a method of contacting with a polar compound. The contacting method is not particularly limited, and any method can be used as long as partial or complete deactivation of the catalyst residue is recognized by this treatment. For example, a method of injecting a polar compound into a polymerization apparatus or piping. A method in which polytrimethylene terephthalate resin before treatment is placed in a polar compound atmosphere. Examples include a method in which a polytrimethylene terephthalate resin before treatment is made into a molten state, a solid state, a solution state, and a dispersed state, and a polar compound is injected, charged, and impregnated therein.

  In order to efficiently reduce the activity of the catalyst residue, the temperature at which the polytrimethylene terephthalate resin reacts with the polar compound is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, and still more preferably 150 ° C. or higher. At this time, the polar compound may be a solid, liquid, gas, or fluid above the critical point. The treatment time is not limited, but if the treatment time is long, it may cause side reactions such as a decrease in molecular weight, decomposition, and coloring, so it is preferable to treat in as short a time as possible. Usually, it is within 60 minutes, more preferably within 30 minutes.

  The polar compound has a heteroatom such as oxygen, nitrogen, phosphorus, sulfur and the like, and more preferably a compound capable of hydrogen bonding. Specific examples of such compounds include alcohols such as water, methanol, ethanol, propanol, PDO, 1,4-butanediol, ethylene glycol, glycerin, and ethanolamine. Phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, phosphorous acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, phenylphosphonic acid, etc. Phosphorus compounds. Acids such as formic acid, acetic acid, propionic acid, hydrogen chloride and sulfuric acid. Nitrogen-containing compounds such as ammonia, methylamine, dimethylamine, ethylenediamine, triethylamine, ethyleneimine and the like can be mentioned, and water and phosphorus compounds are preferred from the viewpoint of handleability and toxicity. The ratio of both compounds when contacting such a polar compound with the polytrimethylene terephthalate resin is not particularly limited, and may usually be in the range of 100,000 / 1 to 0.000001 / 1 in weight ratio.

In the pre-treatment polytrimethylene terephthalate resin used in the present invention, 0.0001 wt% to 10 wt% of one or more kinds of volatile substances such as a gas such as nitrogen and carbon dioxide, water and 1,3-propanediol in advance. %, And the treatment with the cyclic dimer removal apparatus of the present invention is also possible, and the effect of the invention can be improved because the entrainment effect and the effect of reducing the partial pressure of the cyclic dimer can be improved. Is preferable because it improves further.
The method for containing these gases and volatile substances is not particularly limited, but a specific method is, for example, a method of injecting these gases or volatile substances into a polymerization apparatus or piping. A method in which a polytrimethylene terephthalate resin before treatment is made into a molten thin film and brought into contact with these gases and volatile substances. Examples thereof include a method in which the polytrimethylene terephthalate resin before treatment is in a molten state, a solid state, a solution state, and a dispersed state, and these gases and volatile substances are injected, introduced, and impregnated therein.

The cyclic dimer removing apparatus of the present invention is not particularly limited as long as it can satisfy the following conditions (a), (b), (c) and (d).
(A) Treatment at a temperature equal to or higher than the melting point of the resin under a reduced pressure condition of 3.0 kPa or less.
(B) In the cyclic dimer removing apparatus, a molten resin thin film having a value obtained by dividing the area where the resin is in contact with the gas phase by the resin weight is 1.0 cm ² / g or more.
(C) The filling rate of the molten resin in the void volume in the annular dimer removing device is 40% or less.
(D) The cyclic dimer content after the treatment is reduced by 0.2% by weight or more with respect to the cyclic dimer content of the resin before the treatment.

  As a specific method, for example, a polytrimethylene terephthalate resin before processing is charged into an autoclave capable of depressurization, and a molten resin thin film is formed at the bottom of the autoclave by heating to a temperature equal to or higher than the melting point of the resin. A method of removing the cyclic dimer under reduced pressure. A metering pump is installed above and below a cylindrical device that can be depressurized and temperature controlled, and a thin film is formed by casting molten resin on the inner wall of the device by introducing and extracting polytrimethylene terephthalate resin at a constant speed. Method. A support having a wire-like, net-like, plate-like, or porous plate-like structure is installed in the apparatus for the purpose of expanding the area where the molten resin is in contact with the gas phase, and the molten resin flows through this. A method of forming a thin film on a support by stretching.

A rotating shaft with a helical spatula attached to a rotating bearing and a device inner wall or having a clearance of several millimeters with respect to the device inner wall is installed inside the device, and the molten resin is applied to the device inner wall by rotating the spatula. A method of renewing the surface of a molten resin thin film while forming a thin film. A method of subjecting the resin to a reduced pressure treatment under an operating condition in which a resin filling rate is 30% or less using a commercially available kneader with a vacuum vent or an extruder with a vacuum vent. The method etc. which carry out pressure reduction processing using a commercially available thin film evaporator are mentioned.
In addition, a nozzle capable of directly introducing a gas such as nitrogen or carbon dioxide or a volatile substance such as water or 1,3-propanediol is installed in the above cyclic dimer removing apparatus, and processing is performed while continuously introducing these nozzles. A method is also possible, and it is preferable because the cyclic dimer can be more efficiently removed by reducing the partial pressure of the cyclic dimer in the apparatus.

  In the present invention, various additives such as a matting agent, a heat stabilizer, a flame retardant, an antistatic agent, an antifoaming agent, a color adjusting agent, an antioxidant, an ultraviolet absorber, a crystal nucleating agent, an increase agent are added as necessary. A whitening agent or the like can be copolymerized or mixed. These additives can be introduced at any stage of the polymerization. In particular, a stabilizer is preferably introduced at any stage of the polymerization, preferably before polycondensation of BHPT, so that the whiteness and melt stability of PTT can be improved and the production of acrolein, allyl alcohol, and the like can be suppressed. As the stabilizer, a pentavalent or trivalent phosphorus compound or a hindered phenol compound is preferable. Examples of pentavalent or trivalent phosphorus compounds include trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, phenylphosphonic acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, phosphoric acid, phosphorous acid Examples of the acid include trimethyl phosphate, phenylphosphonic acid and phosphoric acid.

  By introducing a phosphorus compound at any stage of polymerization, preferably before polycondensation of BHPT, it is possible to reduce the activity of the polymerization catalyst involved in the production of cyclic dimer, and the cyclic dimer removal apparatus of the present invention In combination, the effect of reducing the cyclic dimer content is more preferable. Moreover, it is also possible to add to the polytrimethylene terephthalate resin manufactured using the cyclic dimer removal apparatus of this invention. The amount of the phosphorus compound to be added is preferably 2 to 250 ppm, more preferably 5 to 150 ppm, still more preferably 10 to 100 ppm as the weight ratio of the phosphorus element contained in the PTT.

  A hindered phenol compound is a phenol derivative having a substituent having a steric hindrance at a position adjacent to a phenolic hydroxyl group, and a compound having one or more ester bonds in the molecule. Specifically, pentaerythritol-tetrakis [3- (3,5-di-tertbutyl-4-hydroxyphenyl) propionate], 1,1,3-tris (2-methyl-4-hydroxy-5-tert- Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis {2- [3- ( 3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5 -Tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3- (3-tert-butyl-5-methyl 4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene-bis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. Of these, pentaerythritol-tetrakis [3- (3,5-di-tertbutyl-4-hydroxyphenyl) propionate] is preferable. The amount of the hindered phenol compound to be added is preferably 0.001 to 1% by weight, more preferably 0.005 to 0.5% by weight, and still more preferably as a weight ratio with respect to the obtained polymer. 0.01 to 0.1% by weight. Two or more kinds of these stabilizers can be used in combination.

  Polytrimethylene is characterized in that it has excellent moldability by reducing the content of oligomers produced in the polymerization process, especially cyclic dimers, and the molded product has excellent paint and paste applicability and adhesiveness. Manufacture terephthalate resin at low cost.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited at all by an Example. The main measurement values in the examples were measured by the following methods.
(1) Intrinsic viscosity Intrinsic viscosity [η] is extrapolated to a zero concentration by using an Ostwald viscosity tube and the ratio ηsp / C of specific viscosity ηsp and concentration C (g / 100 ml) using o-chlorophenol at 35 ° C. It was determined according to the following formula.
[η] = lim (ηsp / C)
C → 0

(2) Content of cyclic dimer After dissolving 0.3 g of a sample in a mixture of 5 ml of chloroform and 5 ml of (CF ₃ ) ₂ CHOH, 5 ml of chloroform was further added, and then about 80 ml of acetonitrile was added. The insoluble matter precipitated at this time was filtered off, and all the solutions were collected. Acetonitrile was added to this solution to make a 200 ml solution. This solution was analyzed using high performance liquid chromatography, and the amount of cyclic oligomer was measured. As the column, μBond asphere 15 μC-18-100A 3.9 × 190 mm (manufactured by Waters) was used, and a wavelength of UV 242 nm was used as a detector. The temperature is 45 ° C. and the flow rate is 1.5 ml / min.

(3) Ink adhesion The sample was molded into a flat plate shape by a hot press heated to 260 ° C. using a mold having a length of 10 cm, a width of 10 cm, and a thickness of 3 mm (melting time 5 minutes, molding time 5 minutes, 70 ° C. Cooling time 30 minutes). The molded body was heat-treated for 48 hours with a hot air dryer at 100 ° C., and then kept under conditions of 20 ° C. and 50% RH for 24 hours. This was printed with a PET ink (PET9107 White, manufactured by Jujo Chemical Co., Ltd.) diluted with a Tetron slow-drying solvent, using a T-270 printing plate, dried at 100 ° C. for 80 seconds, and dried at 20 ° C., 50 It was kept for 24 hours under the condition of% RH. The number (A) of the ink film that remained without being peeled off when the cellophane was applied to the ink film with a razor blade and 10 × 10 grid cuts were made at 1 mm intervals and then peeled off at once. I counted. In addition, after the printed product was heat-treated for 48 hours with a 100 ° C. hot air dryer, it was held for 24 hours under the conditions of 20 ° C. and 50% RH, and peeled off when the same cello tape peel test was performed. The remaining number (B) was counted.

[Example 1]
39000 g of dimethyl terephthalate, 34200 g of 1,3-propanediol and 23.4 g of titanium tetrabutoxide were charged into a 100 L autoclave equipped with a plate-like stirring blade, and transesterification was carried out at 220 ° C. while distilling off methanol. The transesterification rate was 95%. After completion of the transesterification reaction, 15.6 g of titanium tetrabutoxide as a catalyst and 19.5 g of trimethyl phosphate as a heat stabilizer were added, and after stirring for 30 minutes, a vacuum of 0.3 torr was distilled while distilling out 1,3-propanediol. The polycondensation reaction was carried out at 260 ° C. for 4 hours. After the reaction, the obtained polymer was extruded from the bottom of the reaction kettle into a rope shape and cut to obtain pellets. The obtained polymer had an intrinsic viscosity of 0.62 dl / g and a cyclic dimer content of 2.62%.

The obtained pellet was screwed at a screw speed of 300 rpm, a resin temperature of 270 ° C., and two reduced pressures using a vented twin screw extruder provided with two reduced pressure zones with a screw diameter of 30 mmφ and L / D = 50.9. The cyclic dimers were removed by melt extrusion at a feed rate of 3.5 kg / hr with both the zones having a degree of vacuum of 1.3 kPa. When the residence time of the extruder at this time was evaluated using color pellets, the residence time in the decompression zone was 2 minutes, the polymer filling rate was 28%, and the resin was in the gas phase from the volume between the cylinder and the screw groove. The value obtained by dividing the contact area by the weight was calculated to be 1.9 cm ² / g.
The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.61 dl / g and a cyclic dimer content of 1.95%.
When the ink adhesiveness of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 100/100 and (B) = 98/100.

[Example 2]
The cyclic dimer was removed under the same conditions as in Example 1 except that the feed rate of the extruder was 1.5 kg / hr. At this time, the residence time in the decompression zone was 2.5 minutes, the polymer filling rate was 16%, and the value obtained by dividing the area between the cylinder and the screw groove by the weight of the area where the resin contacts the gas phase was 2.6 cm ^2. / G.
The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.60 dl / g and a cyclic dimer content of 1.21%.
When the ink adhesiveness of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 100/100 and (B) = 99/100.

[Comparative Example 1]
In Example 1, pellets were produced under the same conditions except that the polycondensation reaction time was 2 hours. The obtained polymer had an intrinsic viscosity of 0.43 dl / g and a cyclic dimer content of 2.63%.
The cyclic dimer was removed under the same conditions as in Example 1 except that this pellet was used. The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.44 dl / g and a cyclic dimer content of 2.59%.

[Comparative Example 2]
The cyclic dimer was removed under the same conditions as in Example 1 except that the feed rate of the extruder was 10.0 kg / hr. At this time, the residence time in the decompression zone was 1.9 minutes, the polymer filling rate was 50%, and the value obtained by dividing the area where the resin was in contact with the gas phase by the volume between the cylinder and the screw groove was 1.5 cm ^2. / G.
The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.62 dl / g and a cyclic dimer content of 2.60%.
When the ink adhesion of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 87/100 and (B) = 64/100.

[Comparative Example 3]
The cyclic dimer was removed under the same conditions as in Example 1 except that the degree of vacuum in the two decompression zones of the extruder was both 3.5 kPa. The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.60 dl / g and a cyclic dimer content of 2.61%.
When the ink adhesion of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 86/100 and (B) = 61/100.

[Example 3]
2.71 g of powder obtained by pulverizing the pellets produced in Example 1 to a particle size of 300 μm or less was uniformly spread on the bottom of a cylindrical 500 ml autoclave having an inner diameter of 10 cm, which was temperature-controlled at 260 ° C. in a nitrogen atmosphere. Immediately after melting, the degree of vacuum was set to 0.3 kPa, and the cyclic dimer was removed over 30 minutes. After the removal treatment, the polymer sampled after quenching had an intrinsic viscosity of 0.66 dl / g and a cyclic dimer content of 0.40%.

[Comparative Example 4]
The cyclic dimer was removed under the same conditions as in Example 3 except that the amount of powder charged was 150 g. The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.59 dl / g and a cyclic dimer content of 2.63%.

[Example 4]
Gear pumps are installed on the top and bottom of a cylindrical device having an inner diameter of 15 cm and a length of 70 cm, which can be operated under reduced pressure and temperature, as shown in FIG. An apparatus for removing a cyclic dimer capable of continuously extracting the resin treated in the apparatus at a constant speed while introducing the molten polytrimethylene terephthalate resin was prepared. In addition, this device is equipped with a rotating bearing and a rotating shaft with three helical spats attached every 60 °, with a clearance of 2 mm with respect to the inner wall of the device. By rotating the spatula, molten resin is applied to the inner wall of the device. While forming a thin film, it was set as the structure which can update the surface of a molten resin thin film.

The temperature of the annular dimer removing device was set to 240 ° C., the degree of vacuum was set to 0.07 kPa, the rotation speed of the spatula inside the device was set to 300 rpm, and the pellets produced in Example 1 were introduced from the upper part of the device at a rate of 10 kg / h. At the same time, the processed resin was extracted from the lower part of the apparatus at the same rate and sampled. The residence time at this time is 4.8 minutes, the polymer filling rate is 6.5%, and the value obtained by dividing the area where the resin is in contact with the gas phase by the volume between the cylinder and the screw groove is 4.1 cm ² / g. It was calculated.
The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.65 dl / g and a cyclic dimer content of 0.67%.
When the ink adhesion of the polymer after the cyclic dimer removal treatment was evaluated, (A) = 100/100 and (B) = 100/100. Furthermore, the molded product once press-molded into a flat plate was pulverized, and the ink adhesion of the molded product press-molded into the flat plate again was evaluated. As a result, (A) = 98/100 and (B) = 92/100.

[Example 5]
The cyclic dimer was removed under the same conditions as in Example 4 except that 0.1 L / h of nitrogen was continuously introduced into the cyclic dimer removal apparatus. The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.66 dl / g and a cyclic dimer content of 0.43%.

[Example 6]
In Example 1, pellets were obtained under the same conditions except that 4.5 g of phosphoric acid was added instead of 19.5 g of trimethyl phosphate after completion of the transesterification reaction. The obtained polymer had an intrinsic viscosity of 0.54 dl / g and a cyclic dimer content of 2.61%. The cyclic dimer was removed under the same conditions as in Example 4 except that this pellet was used. The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.58 dl / g and a cyclic dimer content of 0.61%.
When the ink adhesion of the polymer after the cyclic dimer removal treatment was evaluated, (A) = 100/100 and (B) = 100/100. Furthermore, when the molded object once press-molded into the flat plate was pulverized and the ink adhesion of the molded product press-molded into the flat plate was evaluated again, (A) = 100/100 and (B) = 98/100.

[Example 7]
In Example 1, pellets were produced under the same conditions except that the polycondensation reaction time was 5 hours. The obtained polymer had an intrinsic viscosity of 0.73 dl / g and a cyclic dimer content of 2.62%.
The cyclic dimer was removed under the same conditions as in Example 4 except that this pellet was used. The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.74 dl / g and a cyclic dimer content of 0.55%.

[Example 8]
Using the apparatus of FIG. 2, 240 kg of polytrimethylene terephthalate is polymerized per day by continuous polymerization using dimethyl terephthalate and 1,3-propanediol as raw materials, and the same cyclic dimer removing apparatus as in FIG. Introduced and removed the cyclic dimer. The transesterification reactor and the first and second stirred tank polymerizers use vertical stirred polymerization reactors with anchored stirring blades, and the final reactor discharges molten prepolymer from the holes in the perforated plate. Then, a polymerization vessel was used in which the polymerization was performed under reduced pressure while dropping along the support.

  In the polymerization, dimethyl terephthalate and 1,3-propanediol to which 800 ppm of titanium tetrabutoxide was added based on dimethyl terephthalate were continuously charged into an esterification reactor at a molar ratio of 1: 1.5, and the reaction was performed at 230 ° C. under normal pressure. Esterification is carried out under conditions of a residence time of 180 minutes, polycondensation is carried out under conditions of a vacuum degree of 4 kPa and 250 ° C. and a residence time of 60 minutes in the first stirred tank type polymerizer, and a vacuum degree of 0 in the second stirred tank type polymerizer. Polycondensation was carried out under the conditions of .15 kPa, 255 ° C. and residence time of 60 minutes to produce a prepolymer having an intrinsic viscosity of 0.46 dl / g, which was introduced into the final reactor. In the final reactor, while introducing 6000 μg / g of nitrogen to the prepolymer, polycondensation was performed under the conditions of a vacuum degree of 0.1 kPa and 255 ° C., and the intrinsic viscosity was 1.26 dl / g and the cyclic dimer content was 2.36%. Polytrimethylene terephthalate was produced.

A cyclic dimer removal device is connected to the polymer outlet of the final reactor, the temperature of the cyclic dimer removal device is set to 240 ° C., the degree of vacuum is set to 0.1 kPa, and the number of rotations of the spatula inside the device is set to 300 rpm. Was extracted and sampled.
The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 1.16 dl / g and a cyclic dimer content of 0.48%.
When the ink adhesion of the polymer after the cyclic dimer removal treatment was evaluated, (A) = 100/100 and (B) = 100/100.

  The present invention reduces polytrimethylene terephthalate resin, which is excellent in moldability by reducing the content of cyclic dimer, and the molded product is excellent in paint and paste applicability and adhesiveness. Manufacture at cost.

It is a schematic diagram which shows an example of the apparatus which achieves the method of this invention. It is a schematic diagram which shows an example of the apparatus which achieves the method of this invention.

Explanation of symbols

[Figure 1]
1. 1. An annular dimer removing device 2. Transfer pump Raw material supply port 4. Motor 5. Rotating shaft, helical spatula and falling polymer Pressure reducing exhaust port 7. Inert gas supply port 8. 8. Discharge port Discharge pump

[Figure 2]
1. Polymerizer 1. 2. Raw material supply port Perforated plate 4. 4. Support and falling polymer Vacuum outlet 6 6. Inert gas supply port Peep window 8. 8. Discharge pump Discharge port 10. 10. Transesterification reactor Vent port 12. Stirring blade 13. Transfer pump 14. First stirred tank type polymerizer 15. Vent port 16. Stirring blade 17. Transfer pump 18. Second stirred tank type polymerization 19. Vent port 20. Stirring blade 21. Transfer pump

Claims (3)

Polytrimethylene terephthalate resins having an intrinsic viscosity of 0.5 dl / g or more, in which 80 mol% or more of repeating units are composed of repeating units of trimethylene terephthalate, are represented by the following (a), (b), (c) and (d A method for producing a polytrimethylene terephthalate resin with a reduced content of cyclic dimer, characterized in that the treatment is performed with a cyclic dimer removing device that satisfies the following conditions:
(A) Treatment at a temperature equal to or higher than the melting point of the resin under a reduced pressure condition of 3.0 kPa or less.
(B) In the cyclic dimer removing apparatus, a molten resin thin film having a value obtained by dividing the area where the resin is in contact with the gas phase by the resin weight is 1.0 cm ² / g or more.
(C) The filling rate of the molten resin in the void volume in the cyclic dimer removing device is 40% or less.
(D) The cyclic dimer content after the treatment is reduced by 0.2% by weight or more with respect to the cyclic dimer content of the resin before the treatment.   The polytri of claim 1, wherein the molten resin thin film is formed on the inner wall of the apparatus by means of a spatula and a screw installed in the annular dimer removing apparatus, and the surface of the molten resin thin film is renewed. A method for producing methylene terephthalate resin.   The polytrimethylene terephthalate resin according to claim 1 or 2, wherein the polytrimethylene terephthalate resin before the treatment is continuously supplied to the cyclic dimer removing device, and at the same time, the resin after the treatment is continuously extracted. Production method.

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