JP2008266660A - Polytrimethylene terephthalate resin and process for producing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polytrimethylene terephthalate resin excellent in coating properties of a paint and a paste, and adhesiveness thereof, in addition to excellent moldability. <P>SOLUTION: The polytrimethylene terephthalate resin composed of 80 wt.% or more of repeating unit of polytrimethylene terephthalate and a limiting viscosity of 0.5 dl/g or larger is characterized in satisfying the following conditions of (a) containing 2 wt.% or less of a cyclic dimer and (b) containing terminal carboxyl groups in a range of 0.3-1 mol% to trimethylene terephthalate unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Polyesters, particularly polyethylene terephthalate, have excellent physical and chemical properties and are widely used as fibers, films, and other molded articles, but lack flexibility. On the other hand, polytrimethylene terephthalate obtained by polymerizing terephthalic acid or a lower alcohol ester of terephthalic acid and 1,3-propanediol (also called trimethylene glycol) is a highly flexible material and has a glass transition. It has many features that cannot be obtained with existing materials, such as its temperature and melting point are similar to those of nylon 6 and has little effect on physical properties due to moisture absorption.

However, it has been found that polytrimethylene terephthalate generates an oligomer in the polymerization process, and that the oligomer causes various problems in the spinning, molding process and 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 precipitates on the molding die and causes the appearance and dimensional accuracy of the molded body to be impaired. In addition, since the oligomer bleeds out on the surface of the molded article after being formed into a fiber or a film, the coating property and the adhesive property and the adhesiveness are not always satisfactory.

The oligomer in the polytrimethylene terephthalate produced by melt polymerization is about 2.5 to 3.5% by weight based on the polytrimethylene terephthalate. In addition, about 90% by weight of the oligomer is a cyclic dimer, and the cyclic dimer has a sublimation property and a bleed-out property, and thus becomes a main causative substance causing various problems as described above.
It has long been known that such an oligomer also exists in polyethylene terephthalate having a similar skeleton. However, in the case of polyethylene terephthalate, its abundance is about 1% by weight, and since this oligomer is mostly cyclic trimer and has a higher molecular weight than the cyclic trimer of polytrimethylene terephthalate, it has sublimability and bleed out. The nature is small. Therefore, the degree of problem is more serious with polytrimethylene terephthalate.

  Attempts to reduce the oligomers contained in polytrimethylene terephthalate are already known, and the most effective method is solid-phase polymerization (Japanese Patent Laid-Open No. 8-311177). In this patent document, it is described that, when solid phase polymerization is performed for several hours in a vacuum at around 200 ° C., the oligomer content is 1% by weight or less. However, according to the study by the present inventors, when polytrimethylene terephthalate having a cyclic dimer content of less than 1% by solid phase polymerization is melted again, the cyclic dimer content increases and the melt residence time becomes longer. It was revealed that the value returned to about 2.5 to 3.5% by weight and the value before solid phase polymerization. For this reason, even with polytrimethylene terephthalate that has been solid-phase polymerized, the cyclic dimer bleeds out on the surface of the molded body as crystals of several μm after being melt-molded into fibers, films, injection molded articles, etc. And problems that occurred during use could not be avoided.

  The present invention solves the above problems, has a low content of oligomers, particularly cyclic dimers, produced in the polymerization process, has excellent moldability, and is excellent in moldability as well as in paints and pastes with excellent applicability and adhesiveness. The object is to provide a methylene terephthalate resin.

  In order to solve this problem, the present inventors have analyzed in detail the formation process of the cyclic dimer, the precipitation behavior on the surface of the molded body, the coating property of the molded body, the applicability of the adhesive, and the influence of adhesiveness. As a result, a polytrimethylene terephthalate resin having a cyclic dimer content of 2% by weight or less and a terminal carboxyl group in the range of 0.3 mol% to 1 mol% per trimethylene terephthalate unit is a molded product of cyclic dimer. It has been found that there is little precipitation on the surface, and the coating property of the molded product, the applicability of the paste, and the adhesiveness are greatly improved.

  In addition, the cyclic dimer formation process at the time of melt molding is generated by the unpaired electron of the hydroxyl oxygen at the molecular end attacking the carbonyl carbon of the ester group inside the molecule, and the catalyst used in the polymerization is the ester group. In order to improve the electrophilicity of the carbonyl carbon by coordinating with the carbonyl oxygen, it was found that the nucleophilic attack of the hydroxyl oxygen at the molecular end was increased, and a cyclic dimer was easily formed. Based on the above findings, the present inventors have found that after completion of the polycondensation reaction, the activity of the catalyst coordinated to the carbonyl carbon can be reduced to a specific ratio to suppress the formation of cyclic dimers during post-melt processing. I found it.

  Furthermore, since the polytrimethylene terephthalate resin having a specific amount of terminal carboxyl groups of the present invention is difficult to produce by the solid phase polymerization method, the efficiency can be increased by using a specific cyclic dimer removing apparatus as an alternative production method. The inventors have found that they can be manufactured well and have reached the present invention.

That is, the present invention
1. 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, and satisfying the following conditions (a) and (b) ,
(A) The content of the cyclic dimer is 2% by weight or less (b) the terminal carboxyl group is in the range of 0.3 mol% or more and 1 mol% or less per trimethylene terephthalate unit.

2. The method for producing a polytrimethylene terephthalate resin according to 1 above, wherein after the polycondensation reaction of polytrimethylene terephthalate is completed, an operation for reducing the activity of the catalyst so as to satisfy the following (formula 1) is performed:
CP (min) ≧ 1.2 × CP ₀ (min) (Formula 1)
(CP (catalytic activity parameter) indicates the time (min) required to increase the intrinsic viscosity of polytrimethylene terephthalate from 0.4 dl / g to 0.6 dl / g under the conditions of 260 ° C. and 0.3 Torr. CP ₀ is a parameter before decreasing the activity of the catalyst, and CP is a parameter after decreasing the activity of the catalyst.)

3. A polytrimethylene terephthalate resin with reduced catalyst activity is obtained by using a cyclic dimer removing apparatus having a value obtained by dividing the surface area where the resin is in contact with the gas phase by the weight of the resin, which is 0.4 cm ² / g or more. The method for producing a polytrimethylene terephthalate resin according to 2 above, wherein the treatment is performed for 1 minute or more at a vacuum degree of ˜280 ° C. and 10 Torr or less, and

4). At least one compound selected from phosphoric acid, phosphoric acid ester, phosphorous acid, phosphorous acid ester and phenylphosphonic acid is in the range of 1 × 10 ⁻² to 50 × 10 ⁻² mol% per trimethylene terephthalate unit. It relates to a method for producing a polytrimethylene terephthalate resin as described in 2 or 3 above, wherein the activity of the catalyst is lowered by addition.

  The polytrimethylene terephthalate resin obtained by the present invention has a low content of oligomers, particularly cyclic dimers, produced in the polymerization process, and is excellent in moldability, and the molded body has coating properties and adhesive properties. Is excellent.

  The polytrimethylene terephthalate constituting the polytrimethylene terephthalate resin of the present invention is a polytrimethylene terephthalate 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. When the intrinsic viscosity is less than 0.5 dl / g, the strength of the molded product is low. The upper limit of the intrinsic viscosity is not particularly limited. However, when it exceeds 2 dl / g, the melt viscosity is too high, making the molding process difficult. Therefore, it is preferably 0.7 to 1.5 dl / g, particularly preferably. It is 0.8-1.4 dl / g, Most preferably, it is 0.85-1.3 dl / g.

  As a raw material monomer for forming the main skeleton of polytrimethylene terephthalate of the present invention, in addition to terephthalic acid and 1,3-propanediol, other monomers may be copolymerized with less than 20% by weight of 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 cyclic dimer content in the polytrimethylene terephthalate resin of the present invention is required to be 2% by weight or less based on the weight of the polytrimethylene terephthalate resin in order to avoid problems caused by the cyclic dimer. More preferably, it is 1.8 weight%, More preferably, it is 1.5 weight% or less, Most preferably, it is 1 weight% or less. There is no particular limitation on the method for reducing the cyclic dimer content to 2% by weight or less, and solid phase polymerization or extraction of the cyclic dimer with a polar solvent or the like is possible. In this method, the cyclic dimer is volatilized and removed from the molten polytrimethylene terephthalate resin under reduced pressure using an apparatus.

  The terminal carboxyl group in the polytrimethylene terephthalate resin of the present invention needs to be in the range of 0.3 mol% or more and 1 mol% or less per trimethylene terephthalate unit. When the amount is less than 0.3 mol%, the amount of the cyclic dimer deposited on the surface of the molded body and the particle size thereof are large, and the processability of the molded body, such as paint and paste coating properties and adhesiveness, is not sufficiently improved. . The amount of the terminal carboxyl group is considered to improve not only the polarity of the surface of the molded body but also the processability by improving the precipitation behavior of the cyclic dimer. Furthermore, it is considered that there is an effect of suppressing the formation of cyclic dimer at the time of melt molding by replacing a part of the hydroxyl group at the molecular terminal that is the starting point of the cyclic dimer formation reaction with a carboxyl group.

  On the other hand, when the terminal carboxyl group exceeds 1 mol%, it is not preferable because it adversely affects the color tone and weather resistance of the molded product. More preferably, the terminal carboxyl group is in the range of 0.33 mol% to 0.8 mol% per trimethylene terephthalate unit, and still more preferably in the range of 0.35 mol% to 0.7 mol%. There is no particular limitation on the method for adjusting the terminal carboxyl group, and it is prepared by reacting with a compound such as phthalic anhydride which can introduce a carboxyl group at the terminal by reacting with the terminal hydroxy group at any stage of producing the polymer. Although it is possible, it is preferable that the final step of producing the polymer is melt polycondensation to adjust the terminal carboxyl group generated by the side reaction. When the final step for producing the polymer is solid phase polymerization, the terminal carboxyl group is consumed by the polycondensation reaction as the polycondensation proceeds, and decreases to less than 0.3 mol% per trimethylene terephthalate unit before reaching the predetermined degree of polymerization. Therefore, adjustment is difficult.

Hereafter, the preferable manufacturing method of the polytrimethylene terephthalate resin of this invention is demonstrated.
Although the manufacturing method of the polytrimethylene terephthalate resin of this invention is not specifically limited, It can obtain by reducing the activity of the catalyst which remains in polytrimethylene terephthalate to a specific ratio, and suppressing the production | generation of a cyclic dimer. Furthermore, the effect of the present invention can be further improved by reducing the content of the cyclic dimer in the polymer having the reduced activity of the catalyst by using a specific cyclic dimer removing apparatus.

  Polytrimethylene terephthalate is produced by reacting terephthalic acid and / or its lower alcohol ester with 1,3-propanediol to produce 1,3-propanediol ester of terephthalic acid and / or its oligomer, and then polycondensing it. Is obtained. The terephthalic acid used in the present invention, the lower alcohol ester of terephthalic acid, and 1,3-propanediol may be commercially available or recovered from polytrimethylene terephthalate or polytrimethylene terephthalate products, and preferably have a purity of 95% or more. 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 for smoothly proceeding the polymerization reaction. In the esterification reaction and transesterification reaction, for example, magnesium, calcium, barium, scandium, yttrium, titanium, zirconium, hafnium, manganese, iron, cobalt, nickel, copper, For metals such as zinc, cadmium, aluminum, germanium, tin, lead, antimony, lanthanum, cerium, samarium, ytterbium, sodium methylate, magnesium methylate, aluminum isopropoxide, zinc glycoxide, zinc phenoxide, titanium tetrabutoxide, titanium Alkoxides typified by tetraisopropoxide: and the above metals, lithium acetate, calcium acetate, magnesium acetate, manganese acetate, zinc acetate, zinc butyrate, tin acetate, octet Carboxylic acid salts represented by tin oxalate, tin 2-ethylhexanoate, lead acetate, antimony acetate and titanium oxalate: and the above metals, carbonates represented by calcium carbonate and zinc carbonate: and the above metals Oxides typified by antimony oxide, germanium oxide, lead oxide, tin oxide, amorphous titanium oxide precipitate, amorphous titanium oxide / silica co-precipitate, amorphous zirconia precipitate: , Zinc chloride, zinc iodide, tin chloride, lanthanum chloride, halides represented by samarium chloride: and the above metals, sulfates represented by zinc sulfate, lead sulfate: and the above metals, phosphoric acid Phosphate represented by zinc: and reaction product of the above metal compound represented by titanium tetrabutoxide with phosphoric acid, phosphorous acid, phosphate ester, phosphite ester: and Organotin compounds represented by nobutyltin oxide, dibutyltin oxide, monobutyltin trioctyl ester, dibutyltin diacetate, dibutyltin dilaurate, stannoxane, etc. 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, magnesium, calcium, barium, scandium, yttrium, titanium, zirconium, hafnium, manganese, iron, cobalt, nickel, copper, zinc, cadmium, aluminum, germanium, tin, lead, antimony, Alkoxides represented by metals such as lanthanum, cerium, samarium, ytterbium, sodium methylate, magnesium methylate, aluminum isopropoxide, zinc glycoxide, zinc phenoxide, titanium tetrabutoxide, titanium tetraisopropoxide: and the above metals Lithium acetate, calcium acetate, magnesium acetate, manganese acetate, zinc acetate, zinc butyrate, tin acetate, tin octylate, tin 2-ethylhexanoate, lead acetate, antimony acetate, oxalic acid Carboxylic acid salts represented by tan: and the above metals, carbonates represented by calcium carbonate and zinc carbonate: and the above metals, antimony oxide, germanium oxide, lead oxide, tin oxide, amorphous titanium oxide Oxides represented by precipitates, amorphous titanium oxide / silica coprecipitates, amorphous zirconia precipitates: and the above metals, represented by zinc chloride, zinc iodide, tin chloride, lanthanum chloride, samarium chloride Halides: and the above metals, sulfates represented by zinc sulfate and lead sulfate: and the above metals, phosphates represented by zinc phosphate: and represented by titanium tetrabutoxide Reaction products of the above metal compounds with phosphoric acid, phosphorous acid, phosphoric acid ester, phosphorous acid ester: and monobutyltin oxide, dibutyltin oxide, monobutyltinate Organotin compounds represented by octyl ester, dibutyltin diacetate, dibutyltin dilaurate, stannoxane, etc .: one or more selected from the above catalysts, 0.01 to 0.2% by weight, preferably Add 0.03-0.15 wt%. 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 catalysts are effective for all esterification reactions, transesterification reactions, and polycondensation reactions. It is the most preferred catalyst in that the polycondensation reaction can be carried out with a small amount without being added to the catalyst.

  In the polycondensation reaction, polycondensation may 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. When copolymerizing polytrimethylene terephthalate, a comonomer can be added at any stage of the polymerization.

  The polytrimethylene terephthalate resin of the present invention is obtained by reducing the activity of the catalyst contained in the polytrimethylene terephthalate resin to a specific ratio after completion of the polycondensation reaction. Can be obtained.

The activity of the catalyst in the present invention is represented by the time (CP) required to increase the intrinsic viscosity of polytrimethylene terephthalate from 0.4 dl / g to 0.6 dl / g under the conditions of 260 ° C. and 0.3 Torr. It is preferable to reduce the activity of the catalyst so as to satisfy (Formula 1).
CP (min) ≧ 1.2 × CP ₀ (min) (Formula 1)
(CP ₀ is a parameter before decreasing the activity of the catalyst, and CP is a parameter after decreasing the activity of the catalyst)
In the case of 1.2 × CP ₀ > CP, the degree of improvement is insufficient. On the other hand, there is no particular limitation on the upper limit of CP. More preferably, CP ≧ 1.5 × CP ₀ , still more preferably CP ≧ 1.8 × CP ₀ , and most preferably CP ≧ 2.0 × CP ₀ .

  A method for reducing the activity of the catalyst is not particularly limited, but a specific method includes, for example, a method of contacting with a polar compound. There are no particular limitations on the contact method, and any method that satisfies the (Equation 1) and can partially or completely deactivate the catalyst may be used. For example, a method of injecting a polar compound into the polymerization apparatus, a method of placing polytrimethylene terephthalate in a polar compound atmosphere, a polytrimethylene terephthalate in a molten state, a solid state, a solution state, and a dispersed state, injecting the polar compound into this, Examples of the method include charging and impregnation. In order to efficiently reduce the activity of the catalyst, the temperature at which polytrimethylene terephthalate 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 water, methanol, ethanol, propanol, PDO, 1,4-butanediol, ethylene glycol, glycerin, ethanolamine and other alcohols: phosphoric acid, trimethyl phosphate, triethyl phosphate, phosphorus Phosphorus compounds such as tributyl phosphate, triphenyl phosphate, phosphorous acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite: formic acid, acetic acid, propionic acid, hydrogen chloride, sulfuric acid, etc. Acid: Nitrogen-containing compounds such as ammonia, methylamine, dimethylamine, ethylenediamine, triethylamine, and ethyleneimine are exemplified, but water or a phosphorus compound is preferable from the viewpoint of handleability and toxicity. There are no particular limitations on the ratio of the two compounds when contacting such a polar compound with polytrimethylene terephthalate, and it may be in the range of 100,000 / 1 to 0.01 / 1 by weight.

When a phosphorus compound is used as the polar compound, deterioration of the color tone or the like of the polymer in the process of removing the cyclic dimer described later can be suppressed, which is particularly preferable.
As a phosphorus compound, phosphoric acid, phosphorous acid or its ester, or phenylphosphonic acid is preferable. Phosphate esters and phosphites are alkyl, aryl and hydroxyalkyl esters, specifically trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, tris-2-hydroxyethyl phosphate, Examples include trimethyl phosphate, triethyl phosphite, tributyl phosphite, triphenyl phosphite and the like. These blending amounts are preferably in the range of 1 × 10 ⁻² mol% to 50 × 10 ⁻² mol% per trimethylene terephthalate unit.
If it is less than 1 × 10 ⁻² mol%, it is difficult to reduce the cyclic dimer, and the color tone of the polymer deteriorates during the cyclic dimer removal operation. On the other hand, even if it exceeds 50 × 10 ⁻² mol%, the effect of the invention is not improved and it is not economical. More preferably, it is in the range of 3 × 10 ⁻² mol% to 30 × 10 ⁻² mol%, and further preferably in the range of 5 × 10 ⁻² mol% to 20 × 10 ⁻² mol%.

After the polycondensation reaction of polytrimethylene terephthalate is completed, the polytrimethylene terephthalate resin produced by performing an operation to reduce the activity of the catalyst does not generate a cyclic dimer even if the molded product once melt-molded is further recycled. The effect of the invention can be maintained.
Furthermore, the effect of the invention can be further improved by removing the cyclic dimer from the molten polytrimethylene terephthalate by using a specific cyclic dimer removing device after performing an operation to reduce the activity of the catalyst. .

The cyclic dimer removing device is not particularly limited as long as the value obtained by dividing the surface area of the resin in contact with the gas phase by the weight of the resin is 0.4 cm ² / g or more. Examples of removal devices include a thin-film distillation device, a kneader device with a vacuum vent, and an extrusion with a vacuum vent that can be used by expanding the surface area where the resin contacts the gas phase beyond the vent opening area by lowering the resin filling rate. In addition, an apparatus of any shape including equipment for ensuring the surface area where the resin is in contact with the gas phase, heating equipment, decompression equipment, and recovery equipment for the removed cyclic dimer, such as temperature and vacuum The degree of adjustment can be adjusted, and the equipment has a wire-like, net-like, plate-like, or porous plate-like structure attached to the inside wall of the device and / or inside the device. The polytrimethylene terephthalate melted along the surface of the power equipment such as a screw or screw is used for the weight of the resin or for the spatula or screw attached to the device. Forcibly cast to may be using the device with.

When the value obtained by dividing the surface area of the resin in contact with the gas phase by the resin weight is less than 0.4 cm ² / g, the rate of decrease in the cyclic dimer content is small, and the cyclic dimer content is long until the content decreases to 2% by weight or less. Processing time is required, causing side reactions such as a decrease in molecular weight, decomposition, and coloring of polytrimethylene terephthalate. More preferably, it is not 0.7 cm ² / g or more, still more preferably 1.0 cm ² / g or more, and most preferably 2.0 cm ² / g or more.

  The resin temperature when removing the cyclic dimer is preferably in the range of 230 ° C to 280 ° C. If it is less than 230 degreeC, there exists a possibility that the reduction | decrease rate of cyclic dimer content rate may fall, and polytrimethylene terephthalate may solidify. When the temperature is higher than 280 ° C., side reactions such as a decrease in molecular weight, decomposition, and coloring of polytrimethylene terephthalate easily proceed. More preferably, it is the range of 240 degreeC-275 degreeC, More preferably, it is the range of 245 degreeC-270 degreeC, Most preferably, it is the range of 250 degreeC-265 degreeC.

  The degree of vacuum when removing the cyclic dimer is preferably 10 Torr or less. When the degree of vacuum is larger than 10 Torr, the decrease rate of the cyclic dimer content is small, and it takes a long processing time until the cyclic dimer content decreases to 2% by weight or less, and the molecular weight of polytrimethylene terephthalate decreases. And causes side reactions such as decomposition and coloring. More preferably, it is 5 Torr or less, More preferably, it is 2 Torr or less, Most preferably, it is 0.5 Torr or less, Most preferably, it is 0.1 Torr or less.

  The treatment time for removing the cyclic dimer is preferably 1 minute or longer. If the treatment time is less than 1 minute, it is difficult to reduce the cyclic dimer content to 2% by weight or less. On the other hand, the processing time exceeding 1 minute is not limited. However, if the processing time is too long, side reactions such as a decrease in molecular weight, decomposition, and coloring of polytrimethylene terephthalate may occur. The preferred treatment time is in the range of 1 minute to 90 minutes, more preferably in the range of 1 minute to 60 minutes, and most preferably in the range of 1 minute to 30 minutes.

In addition, polytrimethylene terephthalate was previously incorporated with a gas such as nitrogen or carbon dioxide, or one or more volatile substances such as water or 1,3-propanediol in a range of 0.001 wt% to 10 wt%. Later, by introducing it into the cyclic dimer removing apparatus, it is possible to further improve the rate of decrease in the cyclic dimer content by the accompanying effect.
The polytrimethylene terephthalate resin of the present invention contains various additives as necessary, for example, heat stabilizers, antifoaming agents, color modifiers, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, An optical brightener, for example, a matting agent such as titanium oxide, may be copolymerized or mixed.

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 Using an Ostwald viscosity tube, the ratio ηsp / C of specific viscosity ηsp and concentration C (g / 100 ml) was extrapolated to zero using 35 ° C. and o-chlorophenol, and determined according to the following equation: .
[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) Terminal carboxyl group 100 mg of a sample was dissolved by heating in 5 mL of benzyl alcohol, diluted with 5 mL of chloroform, and titrated with a 0.1 N sodium hydroxide / benzyl alcohol solution and quantified with phenol red as an indicator. .

(4) 260 ° C. Melt Residence Test 1 g of a sample was placed in a glass ampoule, air was removed after vacuuming, and then sealed, and then left in an oil bath at 260 ° C. for 30 minutes. After the treatment, the sample was cooled and a sample was taken out and subjected to various analyses.

(5) 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) that remained without peeling off when the cellophane tape was applied to the ink film part with a razor blade and 10 × 10 grid-cut cuts were made at 1 mm intervals and then peeled off at once. I counted. Also, 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 when the same cellophane tape peel test was conducted. The remaining number (B) without counting was counted.

Example 1
3900 g (20.1 mol) of dimethyl terephthalate, 432 g (45 mol) of 1,3-propanediol and 2.34 g of titanium tetrabutoxide were charged into a 10 L autoclave equipped with a plate-like stirring blade, and methanol was distilled at 220 ° C. The ester exchange reaction was carried out while leaving. The transesterification rate was 95%. After completion of the transesterification reaction, 1.56 g of titanium tetrabutoxide as a catalyst and 1.95 g of trimethyl phosphate as a heat stabilizer were added. After stirring for 30 minutes, a vacuum of 0.3 torr was distilled off while distilling 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, a cyclic dimer content of 2.62%, and a terminal carboxyl group of 0.33 mol% per trimethylene terephthalate unit.

To the obtained pellet, triphenyl phosphate was impregnated and mixed by 0.35% by weight. Using a twin-screw extruder with a vent provided with two decompression zones with a screw diameter of 30 mmφ and L / D = 50.9, a screw rotation speed of 100 rpm, a resin temperature of 260 ° C., and vacuum in two decompression zones The cyclic dimer was removed by melt extrusion at a feed rate of 2 kg / hr at a degree of 10 Torr. At this time, the residence time of the extruder and the polymer filling rate were evaluated using color pellets. As a result, the residence time in the decompression zone was 3 minutes, the polymer filling rate was 20%, and the volume between the cylinder and the screw groove was The value obtained by dividing the surface area of the resin in contact with the gas phase by the weight of the resin was calculated to be 2.0 cm ² / g.

The polymer after the cyclic dimer removal treatment had an intrinsic viscosity of 0.61 dl / g, a cyclic dimer content of 1.80%, and the terminal carboxyl group was 0.35 mol% per trimethylene terephthalate unit.
The polymer after the cyclic dimer removal treatment was subjected to a melt retention test at 260 ° C., the intrinsic viscosity was 0.60 dl / g, the cyclic dimer content was 1.82%, and the terminal carboxyl group was 0.37 mol% per trimethylene terephthalate unit.
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 product once press-molded into a flat plate was pulverized and the ink adhesion property of the molded product press-molded into a flat plate was evaluated again, (A) = 99/100 and (B) = 100/100.

(Reference Example 1)
Polytrimethylene terephthalate was subjected to melt polycondensation under the same conditions as in Example 1 while referring to the torque meter attached to the stirring blade. The time (CP ₀ ) required to polymerize polytrimethylene terephthalate having an intrinsic viscosity of 0.6 dl / g from polytrimethylene terephthalate having an intrinsic viscosity of 0.4 dl / g was 32 minutes. Further, polytrimethylene terephthalate was melt polycondensed again under the same conditions as in Example 1, and when the intrinsic viscosity reached 0.4 dl / g, 0.35% by weight of triphenyl phosphate was added to the autoclave. Then, after the polycondensation reaction was continued, the time (CP) required to polymerize polytrimethylene terephthalate having an intrinsic viscosity of 0.6 dl / g was 45 minutes.

(Example 2)
Under the same conditions as in Example 1, after performing a polycondensation reaction at 260 ° C. for 4 hours at a vacuum of 0.3 Torr, 0.2% by weight of trimethyl phosphate was added to the autoclave, and then the polycondensation reaction was performed for 30 minutes. After continuing, 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 0.63 dl / g, a cyclic dimer content of 2.60%, and a terminal carboxyl group of 0.34 mol% per trimethylene terephthalate unit.

Immediately after 2.71 g of powder obtained by pulverizing the obtained pellets to a particle size of 300 μm or less was uniformly spread on the bottom of a cylindrical autoclave having an inner diameter of 10 cm adjusted to 260 ° C. in a nitrogen atmosphere, the powder was immediately melted. The cyclic dimer was removed over 10 minutes at a vacuum of 0.2 Torr. After the removal treatment, the polymer sampled after quenching had an intrinsic viscosity of 0.66 dl / g, a cyclic dimer content of 0.42%, and the terminal carboxyl group was 0.35 mol% per trimethylene terephthalate unit.

  The polymer after the cyclic dimer removal treatment was subjected to a melt retention test at 260 ° C., the intrinsic viscosity was 0.64 dl / g, the cyclic dimer content was 0.44%, and the terminal carboxyl group was 0.36 mol% per trimethylene terephthalate unit.

(Reference Example 2)
The same procedure as in Reference Example 1 was performed except that 0.2% by weight of trimethyl phosphate was added instead of 0.35% by weight of triphenyl phosphate, and polytrimethylene terephthalate having an intrinsic viscosity of 0.6 dl / g. The time (CP) required to polymerize was 52 minutes.

(Example 3)
The same operation as in Example 2 was performed except that 2.78 g and 1.85 g of tin 2-ethylhexanoate were added instead of 2.34 g and 1.56 g of titanium tetrabutoxide, respectively. The viscosity was 0.73 dl / g, the cyclic dimer content was 2.50%, and the terminal carboxyl group was 0.32 mol% per trimethylene terephthalate unit.

In the same manner as in Example 2, 2.71 g of powder obtained by pulverizing the obtained pellets to a particle size of 300 μm or less was evenly applied to the bottom of a cylindrical autoclave having an inner diameter of 10 cm that was adjusted to 260 ° C. in a nitrogen atmosphere. Immediately after laying and melting, the degree of vacuum was 0.2 Torr, and the cyclic dimer was removed over 10 minutes. After the removal treatment, the polymer sampled after quenching had an intrinsic viscosity of 0.75 dl / g, a cyclic dimer content of 0.35%, and the terminal carboxyl group was 0.35 mol% per trimethylene terephthalate unit.

  The polymer after the cyclic dimer removal treatment was subjected to a melt retention test at 260 ° C., the intrinsic viscosity was 0.73 dl / g, the cyclic dimer content was 0.37%, and the terminal carboxyl group was 0.37 mol% per trimethylene terephthalate unit.

(Reference Example 3)
Instead of 2.34 g and 1.56 g titanium tetrabutoxide, 2.78 g and 1.85 g tin 2-ethylhexanoate were added respectively, and trimethyl phosphate was added instead of 0.35 wt% triphenyl phosphate. When (CP ₀ ) and (CP) were evaluated in the same manner as in Reference Example 1 except that 0.2% by weight was added, (CP ₀ ) was 25 minutes and (CP) was 42 minutes.

Example 4
In Example 1, pellets obtained by performing a polycondensation reaction at 260 ° C. for 4 hours at a vacuum of 0.3 Torr were pulverized to a particle size of 300 μm or less and subjected to Soxhlet extraction with acetone for 24 hours to remove cyclic dimers. did. The dried polymer had an intrinsic viscosity of 0.62 dl / g, a cyclic dimer content of 1.12%, and a terminal carboxyl group of 0.33 mol% per trimethylene terephthalate unit.

The polymer after the cyclic dimer removal treatment was subjected to a melt retention test at 260 ° C., the intrinsic viscosity was 0.60 dl / g, the cyclic dimer content was 2.24%, and the terminal carboxyl group was 0.35 mol% per trimethylene terephthalate unit.
When the ink adhesion of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 99/100 and (B) = 99/100. 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. The results were (A) = 67/100 and (B) = 47/100.

(Example 5)
A polymer after melt polycondensation obtained by performing the same operation as in Example 2 except that 0.2% by weight of water was added instead of 0.2% by weight of trimethyl phosphate had an intrinsic viscosity of 0.59 dl / g. The cyclic dimer content was 2.62%, and the terminal carboxyl group was 0.38 mol% per trimethylene terephthalate unit. The pellets were pulverized to a particle size of 300 μm or less and subjected to Soxhlet extraction with acetone for 24 hours to remove the cyclic dimer. The dried polymer had an intrinsic viscosity of 0.58 dl / g, a cyclic dimer content of 1.10%, and a terminal carboxyl group of 0.41 mol% per trimethylene terephthalate unit.

The polymer after the cyclic dimer removal treatment was subjected to a melting retention test at 260 ° C., the intrinsic viscosity was 0.55 dl / g, the cyclic dimer content was 1.12%, and the terminal carboxyl group was 0.43 mol% per trimethylene terephthalate unit.
When the ink adhesiveness of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 99/100 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) = 100/100 and (B) = 99/100.

(Reference Example 4)
The same procedure as in Reference Example 2 was performed except that 0.2% by weight of water was added instead of 0.2% by weight of trimethyl phosphate, and polytrimethylene terephthalate having an intrinsic viscosity of 0.6 dl / g was polymerized. The time required for (CP) was 61 minutes.

(Comparative Example 1)
In Example 1, the polymer obtained by subjecting the pellet obtained by performing the polycondensation reaction at 260 ° C. for 4 hours at a vacuum degree of 0.3 Torr to 205 ° C. for 30 hours under a nitrogen stream has an intrinsic viscosity of 0. .92 dl / g, cyclic dimer content 1.02%, and terminal carboxyl group was 0.24 mol% per trimethylene terephthalate unit.
The polymer after the solid phase polymerization was subjected to a melt retention test at 260 ° C., the intrinsic viscosity was 0.86 dl / g, the cyclic dimer content was 2.13%, and the terminal carboxyl group was 0.27 mol% per trimethylene terephthalate unit.

  When the ink adhesion of the polymer after the solid phase polymerization was evaluated, it was (A) = 69/100 and (B) = 52/100. Furthermore, when the molded product once press-molded into a flat plate was pulverized and the ink adhesion of the molded product press-molded into a flat plate again was evaluated, they were (A) = 55/100 and (B) = 34/100. At this time, a bleedout of a cyclic dimer was observed on the surface of the molded body (B).

(Comparative Example 2)
In Example 2, in the step of removing the cyclic dimer, except that the amount of powder was 300 g,
The polymer obtained by the same operation had an intrinsic viscosity of 0.65 dl / g, a cyclic dimer content of 2.38%, and a terminal carboxyl group of 0.36 mol% per trimethylene terephthalate unit.
When the ink adhesiveness of the polymer after the cyclic dimer removal treatment was evaluated, it was (A) = 67/100 and (B) = 55/100. 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) = 61/100 and (B) = 56/100.

Claims (2)

Including the steps (1) and (2) below, the intrinsic viscosity of at least 80% by weight of repeating units consisting of trimethylene terephthalate units is 0.5 dl / g or more, and the following (a) and (b) A method for producing a polytrimethylene terephthalate resin that satisfies a condition.
(A) The content of the cyclic dimer is 2% by weight or less (b) the terminal carboxyl group is in the range of 0.3 mol% or more and 1 mol% or less per trimethylene terephthalate unit (1)
After completion of the melt polycondensation reaction of polytrimethylene terephthalate, at least one selected from phosphoric acid, phosphoric acid ester, phosphorous acid, phosphorous acid ester and phenylphosphonic acid so as to satisfy the following (formula 1) The process of implementing operation which reduces the activity of a catalyst by adding a compound in the range of 1 * 10 ^<-2 > -50 * 10 ^{< -2} > mol% per trimethylene terephthalate unit.
CP (min) ≧ 1.2 × CP ₀ (min) (Formula 1)
(CP (catalytic activity parameter) indicates the time (min) required to increase the intrinsic viscosity of polytrimethylene terephthalate from 0.4 dl / g to 0.6 dl / g under the conditions of 260 ° C. and 0.3 Torr. CP ₀ is a parameter before reducing the activity of the catalyst, and CP is a parameter after reducing the activity of the catalyst.)
Process (2)
A step of volatilizing and removing the cyclic dimer from the molten polytrimethylene terephthalate resin under reduced pressure. In step (2), a polytrimethylene terephthalate resin having reduced catalyst activity is used, and a cyclic dimer removing device having a value obtained by dividing the surface area of the resin in contact with the gas phase by the resin weight is 0.4 cm ² / g or more. The process for producing a polytrimethylene terephthalate resin according to claim 1, wherein the resin temperature is 230 to 280 ° C and the degree of vacuum is 10 Torr or less for 1 minute or more.