JP2006063324A - Polytrimethylene terephthalate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polytrimethylene terephthalate which has a low content of a cyclic dimer and hardly produces the cyclic dimer when it is melt molded. <P>SOLUTION: The polytrimethylene terephthalate is essentially composed of a trimethylene terephthalate unit, has intrinsic viscosity of 0.5-1.6 dL/g and contains 0.01-0.5 wt% of a phosphonate and/or a phosphinic acid compound, and the method for producing the same is disclosed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to polytrimethylene terephthalate and a method for producing the same. More specifically, the present invention relates to polytrimethylene terephthalate and a method for producing the same, which produce a small amount of cyclic dimer during melt molding.

Polyester is widely used in fibers, films and other molded articles because of its excellent mechanical, physical and chemical performance. In recent years, polytrimethylene terephthalate fibers have been attracting attention because they have a soft texture, excellent elastic recovery, and easy dyeability not found in polyethylene terephthalate fibers.
However, this polytrimethylene terephthalate tends to form a cyclic dimer during polycondensation. This cyclic dimer adheres as a foreign matter in the vicinity of the spinneret in the spinning process and causes yarn breakage. In addition, a cyclic dimer may precipitate during processing such as weaving and knitting, thereby reducing processing stability. In order to solve such a problem, polytrimethylene terephthalate in which polytrimethylene terephthalate is solid-phase polymerized under reduced pressure and the content of the low polymerization degree component is 1% by weight or less has been proposed (Patent Document 1). reference). If this method is used, the amount of the cyclic dimer in the polytrimethylene terephthalate chip can be reduced. However, since the cyclic dimer is regenerated when remelted during molding, no fundamental improvement has been achieved.
On the other hand, a method has been proposed in which the activity of the catalyst is reduced using a phosphoric acid compound to suppress the precipitation of cyclic dimers (see Patent Document 2). However, it is desired to further suppress the content and generation amount of the cyclic dimer.
JP-A-8-311177 JP 2004-51921 A

An object of the present invention is to provide polytrimethylene terephthalate which has a low content of cyclic dimer and hardly generates a cyclic dimer during melt molding.
In addition, an object of the present invention is to provide a method for producing the polytrimethylene terephthalate.

  The present invention mainly comprises trimethylene terephthalate units, and has an intrinsic viscosity (measured in an o-chlorophenol solution at 35 ° C.) of 0.5 to 1.6 dL / g, 0.01 to 0.5% by weight. And a polytrimethylene terephthalate (A) containing a compound represented by the following formula (I) and / or a compound represented by the following formula (II).

[In the formula (I), R ₁ , R ₂ and R ₃ are the same or different and are hydrocarbon groups having 1 to 10 carbon atoms. Moreover, n is an integer of 1-5. M is an alkali metal atom or an alkaline earth metal atom. When M is an alkali metal atom, m = 1, and when M is an alkaline earth metal atom, m = 2. ]

[In formula (II), R ₄ and R ₅ are the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. ]
Here, the content of the cyclic dimer in the polytrimethylene terephthalate (A) is preferably 0.01 to 2% by weight.
The polytrimethylene terephthalate (A) preferably has a regenerated cyclic dimer production rate at 260 ° C. in a nitrogen atmosphere of 0.01% by weight / min or less.
Furthermore, the amount of the titanium metal element in the catalyst residue dissolved and contained in the polytrimethylene terephthalate (A) is preferably 2 to 150 with respect to the total dicarboxylic acid component contained as a constituent component of the polytrimethylene terephthalate. Mmol%.
Next, in the present invention, the main repeating unit is composed of trimethylene terephthalate units, and the intrinsic viscosity (measured in an o-chlorophenol solution at 35 ° C.) is 0.5 to 1.6 dL / g, The present invention relates to polytrimethylene terephthalate (B) containing a compound represented by the above formula (I) and / or a compound represented by the above formula (II) in an amount of more than 30% by weight and not more than 30% by weight.
Next, the present invention is mainly composed of trimethylene terephthalate units and has an intrinsic viscosity (measured in an o-chlorophenol solution at 35 ° C.) of 0.5 to 1.6 dL / g of polytrimethylene terephthalate (C) 100 weight. The present invention relates to a method for producing polytrimethylene terephthalate (A) comprising melt-kneading 0.5 to 20 parts by weight of polytrimethylene terephthalate (B) with respect to parts.
Next, the present invention includes esterifying terephthalic acid with trimethylene glycol or transesterifying an ester-forming derivative of terephthalic acid with trimethylene glycol, and then polymerizing to obtain an intrinsic viscosity (in an o-chlorophenol solution, In the method for producing polytrimethylene terephthalate having a measurement of 0.5 to 1.6 dL / g (measured at 35 ° C.), the compound represented by the above formula (I) and / or the compound represented by the above formula (II) The polytrimethylene terephthalate (A) is produced by adding the polytrimethylene terephthalate in a content of 0.01 to 0.5% by weight.
In this production method, after the intrinsic viscosity of polymethylene terephthalate (measured in an o-chlorophenol solution at 35 ° C.) is 0.4 dL / g or more, the compound represented by the above formula (I) and / or the above It is preferable to add a compound represented by the formula (II).

  According to the present invention, there are provided polytrimethylene terephthalate having a low content of cyclic dimer and hardly causing the cyclic dimer to precipitate during melt molding, and a method for producing the same.

Hereinafter, the present invention will be described in more detail.
<Polytrimethylene terephthalate (A)>
The polytrimethylene terephthalate (A) of the present invention (hereinafter sometimes abbreviated as “PTT (A)”) is a polyester mainly composed of trimethylene terephthalate units represented by the following formula.

Here, “mainly” means 90 mol% or more of all repeating units. The trimethylene terephthalate unit is preferably 95 to 100 mol% in all repeating units.
PTT (A) may be copolymerized with a third component constituting a repeating unit other than the trimethylene terephthalate unit. The third component may be either a dicarboxylic acid component or a glycol component. As the dicarboxylic acid component, aromatic dicarboxylic acid such as 2,6-naphthalenedicarboxylic acid, isophthalic acid or phthalic acid, aliphatic dicarboxylic acid such as adipic acid, azelaic acid, sebacic acid or decanedicarboxylic acid, or cyclohexanedicarboxylic acid An alicyclic dicarboxylic acid etc. are mentioned. Examples of the glycol component include ethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, hexamethylene glycol, cyclohexane dimethanol, and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane. Or 2 or more types can be used. The repeating unit composed of the third component is preferably 0 to 10 mol%, more preferably 0 to 5 mol% of all repeating units.

(Intrinsic viscosity)
PTT (A) has an intrinsic viscosity of 0.5 to 1.6 dL / g. The intrinsic viscosity is a value measured at 35 ° C. in o-chlorophenol. When the intrinsic viscosity is less than 0.5 dL / g, the mechanical strength of the finally obtained fiber becomes insufficient. On the other hand, when it exceeds 1.6 dL / g, the handleability is lowered, which is not preferable. The intrinsic viscosity is preferably 0.55 to 1.5 dL / g, more preferably 0.55 to 1.45 dL / g, and even more preferably 0.6 to 1.4 dL / g.
In order to set the intrinsic viscosity of PTT (A) within the above range, solid phase polymerization is preferably performed. In solid-phase polymerization, pellets of polytrimethylene terephthalate are kept at a high temperature below the melting point, preferably 190 to 210 ° C., and stirred for several hours to several tens of hours under a high vacuum of 150 Pa or less or under a nitrogen stream. Alternatively, it can be performed in a stationary state. This solid phase polymerization may be continuous or batchwise.

(Compound represented by formula (I) or (II))
The PTT (A) of the present invention contains 0.01 to 0.5% by weight of the phosphonate represented by the above formula (I) and / or the phosphinic acid compound represented by the above formula (II). When the content of these compounds is less than 0.01% by weight, the amount of regenerated cyclic dimer increases, which is not preferable. On the other hand, when the content exceeds 0.5% by weight, the heat resistance of polytrimethylene terephthalate may decrease. . The content of the compound represented by the formula (I) and / or (II) is preferably 0.03 to 0.3% by weight.

In the above formula _(I), the hydrocarbon group having 1 to 10 carbon atoms constituting R 1, _{R 2} and _{R 3,} include alkyl groups, aromatic groups having 6 to 10 carbon atoms having 1 to 10 carbon atoms It is done. Among these, examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a tertiary butyl group. In addition, examples of the aromatic group having 6 to 10 carbon atoms include a phenyl group and a benzyl group. Of these, a methyl group, an ethyl group, an isopropyl group, or a tertiary butyl group is preferable.
In the formula (I), n is an integer of 1 to 5, preferably 1 or 2.
Further, M is an alkali metal atom or an alkaline earth metal atom. When M is an alkali metal atom, m = 1, and when M is an alkaline earth metal atom, m = 2. Examples of the alkali metal atom include potassium and sodium. Examples of alkaline earth metal atoms include calcium, magnesium, strontium, barium and the like. Preferably it is calcium.

  Specific examples of the compound represented by the formula (I) include calcium diethylbis (((3,5-dimethyl-4-hydroxyphenyl) methyl) phosphonate), magnesium diethylbis (((3,5-dimethyl-4-hydroxy). Phenyl) methyl) phosphonate), calcium diethylbis (((3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl) methyl) phosphonate), magnesium diethylbis (((3,5-bis (1 , 1-dimethylethyl) -4-hydroxyphenyl) methyl) phosphonate), calcium diethylbis (((3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl) ethyl) phosphonate), magnesium diethylbis ((((3,5-bis (1,1-dimethylethyl) -4-hydroxy Eniru) ethyl) phosphonate), and the like.

In the formula (II), the hydrocarbon group having 1 to 10 carbon atoms constituting the _{R 4} and _{R 5,} alkyl group having 1 to 10 carbon atoms and an aromatic group having 6 to 10 carbon atoms. Among these, examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, an isobutyl group, and a tertiary butyl group. Examples of the aromatic group having 6 to 10 carbon atoms include a phenyl group and a benzyl group. In the above formula (II), the phosphorus atom is represented as a pentavalent compound, but in the case of a compound having a pentavalent phosphorus atom and a trivalent tautomer of the phosphorus atom, the trivalent phosphorus The compound is also included in the phosphorus compound represented by the above formula (II).

  Specific examples of the phosphorus compound represented by the general formula (II) include phenylphosphinic acid, methyl phenylphosphinate, ethyl phenylphosphinate, phenylphenylphosphinate, benzylphosphinic acid, methyl benzylphosphinate, ethyl benzylphosphinate, Examples include phenyl benzylphosphinate.

  The content of the compound represented by the formula (I) or (II) in the PTT (A) is determined by nuclear magnetic resonance spectrum in addition to quantitative analysis of alkali metal elements, alkaline earth metal elements, and phosphorus elements. It can be quantified.

(Cyclic dimer content)
The content of the cyclic dimer represented by the following formula (1) in the PTT (A) of the present invention is preferably 0.01 to 2% by weight. When the content of the cyclic dimer is within the above range, the spinning property of PTT (A) is good. The cyclic dimer content is more preferably 0.02 to 2% by weight, still more preferably 0.03 to 1.5% by weight. In order to make the content of the cyclic dimer 0.01 to 2% by weight, it is effective to perform solid state polymerization after melt polymerization until the intrinsic viscosity becomes 0.5 to 1.0 dL / g. Since the cyclic dimer has a particularly high sublimation property and hot water solubility, if the original content is large, it becomes a main causative substance that causes problems during processing such as weaving and knitting as described above.

(Regeneration cyclic dimer generation rate)
PTT (A) preferably has a regenerated cyclic dimer production rate at 260 ° C. in a nitrogen atmosphere of 0.01 wt% / min or less, more preferably 0.001 to 0.01 wt% / min. More preferably, it is 0.001-0.009 weight% / min or less. Even more preferably, it is 0.001 to 0.008 wt% / min or less.
Here, the regenerated cyclic dimer is a cyclic dimer represented by the formula (1) which is regenerated as a thermodynamically stable compound by breaking the ester bond of a part of the polyester linearly connected by the repeating unit. means. The regenerated cyclic dimer production rate is an increase in the content% by weight of the cyclic dimer represented by the formula (1) contained in PTT (A) per minute. Even if the cyclic dimer content is small, if the regenerated cyclic dimer formation rate is high, the cyclic dimer regeneration amount at the time of melt spinning increases, and the process condition in the spinning process and subsequent weaving and knitting processes is unstable. It may become. In order to make the cyclic dimer formation rate within this range, it is effective to incorporate the compound represented by the above formula (I) and / or (II) into PTT (A) within the above range.

(Hue)
PTT (A) is a fiber product finally obtained when the color b value of L ^* a ^* b ^* color system is in the range of −5 to 10 after heat treatment at 140 ° C. for 2 hours. The appearance of is good. The color b value is more preferably in the range of -4 to 9, and most preferably in the range of -3 to 8. Here, in order to make the color b value in the range of -5 to 10, it is effective to set the intrinsic viscosity in the melt polymerization stage to a range of 0.5 to 1.0 dL / g and to perform solid-phase polymerization after the melt polymerization. It is.

(Phosphorus element content)
PTT (A) preferably has a phosphorus element content of 10 to 1,000 ppm. The phosphorus element content is more preferably 15 to 700 ppm, still more preferably 20 to 500 ppm. Even more preferably, it is 20 to 400 ppm, and particularly preferably 20 to 300 ppm. If the amount of phosphorus element is less than 10 ppm, it may be undesirable in terms of cyclic dimer content, regenerated cyclic dimer formation rate, and hue as described above. On the other hand, when it is more than 1,000 ppm, the heat resistance of PTT (A) may be unfavorably lowered. The phosphorus element may be derived from a single phosphorus compound, but is preferably a compound represented by the formula (I) and / or (II) described above.

(Alkaline earth metal element content)
PTT (A) preferably has an alkaline earth metal element content of 5 to 300 ppm. More preferably, it is 10-250 ppm, More preferably, it is 15-200 ppm. When the alkaline earth metal element content is less than 5 ppm, it may be unfavorable in terms of the rate of regenerated cyclic dimer formation. On the other hand, if it exceeds 300 ppm, the heat resistance of the resulting PTT (A) may be unfavorable.

(Dipropylene glycol content)
PTT (A) preferably has a dipropylene glycol content of 0.1 to 2.0% by weight. When it exists in said range, the heat resistance of PTT (A) and the mechanical strength of the fiber finally obtained become high. The dipropylene glycol content is more preferably 0.15 to 1.8% by weight, and still more preferably 0.2 to 1.5% by weight. In PTT (A), in order to make the dipropylene glycol content 0.1 to 2.0% by weight, the ratio of trimethylene glycol to terephthalic acid or dimethyl terephthalate used as a raw material is 1.2 to 2.2. Is effective.

PTT (A) preferably satisfies the following requirements (a) to (d) simultaneously.
(A) The intrinsic viscosity is 0.5 to 1.6 dL / g.
(B) The dipropylene glycol content is 0.1 to 2.0% by weight,
(C) The content of the cyclic dimer is 0.01 to 2% by weight,
(D) The color b ^* value after crystallization by heat treatment at 140 ° C. for 2 hours is −5 to 10.

<Production of PTT (A), titanium metal element amount>
PTT (A) can be produced by directly esterifying terephthalic acid with trimethylene glycol and then polymerizing it, and then adding the compound represented by the above formula (I) and / or (II). In addition, an ester-forming derivative of terephthalic acid such as dimethyl terephthalate is subjected to an ester exchange reaction with trimethylene glycol and then polymerized, and then added by a compound represented by the above formula (I) and / or (II). can do.
Here, examples of the ester-forming derivative include lower dialkyl esters, lower diaryl esters, and acid halides. Specific examples include dimethyl ester, diethyl ester, dibutyl ester, diphenyl ester, acid chloride, and acid bromide. Among these, dimethyl ester can be preferably used.

  In the polymerization, it is preferable to use a titanium compound as a polymerization catalyst in order to reduce foreign matters resulting from the catalyst. The titanium compound is preferably an organic titanium compound that is soluble in the polymer. From the viewpoint of polycondensation reactivity, the hue of the resulting polyester, and heat resistance, the titanium compound is 2 to 150 as a titanium metal element in the catalyst residue with respect to all dicarboxylic acid components contained as components of polytrimethylene terephthalate. It is preferably contained in a mmol%. More preferably, it is 10-100 mmol%, More preferably, it is 20-50 mmol%. If it is less than 2 mmol%, the polycondensation reaction may not proceed sufficiently. On the other hand, when it exceeds 150 mmol%, it may become yellowish. The titanium compound used as the polymerization catalyst is limited to an organic titanium compound soluble in polyester and a titanium metal element derived from an organic titanium compound contained as an impurity in titanium oxide used as a matting agent. . On the other hand, a titanium metal element derived from an inorganic titanium compound insoluble in polyester used as a matting agent is not included. Examples of the titanium compound include titanium titanium and alkoxy titanium such as tetra-n-butoxy titanium. Moreover, the product etc. which made these titanium compounds react with aromatic polyhydric carboxylic acid or its anhydride are mentioned. The total dicarboxylic acid component includes not only terephthalic acid but also dicarboxylic acid copolymerized as the third component.

  In the case of adopting a method of polymerizing an ester-forming derivative of terephthalic acid after undergoing transesterification reaction with trimethylene glycol, as a transesterification catalyst, calcium compound, magnesium compound, manganese compound, zinc compound, etc. You may use together the catalyst used as a transesterification reaction catalyst. However, usually, a method in which the above-described titanium compound is used as both a transesterification catalyst and a polymerization catalyst is preferably employed.

  The compound represented by the above formula (I) or (II) can be added to polytrimethylene terephthalate by any method. For example, polytrimethylene terephthalate may be added after reaching a predetermined viscosity in the polymerization step. The produced polytrimethylene terephthalate may be melt blended using a twin screw extruder or the like. You may perform melt blending by a masterbatch system. The compound represented by formula (I) or (II) can be added to polytrimethylene terephthalate in the form of powder or dissolved / dispersed in a solvent.

Therefore, PTT (A) is a method of esterifying terephthalic acid with trimethylene glycol or transesterifying an ester-forming derivative of terephthalic acid with trimethylene glycol and then polymerizing to produce polytrimethylene terephthalate. The compound represented by the above formula (I) or (II) can be produced by adding so that the content in polytrimethylene terephthalate is 0.01 to 0.5% by weight.
The compound represented by the formula (I) or (II) should be added after the intrinsic viscosity of polytrimethylene terephthalate is 0.4 dL / g or more, preferably 0.5 dL / g or more and 1.6 dL / g or less. Is preferred.

  PTT (A) is preferably in the form of a chip having a weight of 10 to 40 mg / piece. This shape is preferable in that the solid-phase polymerization rate is sufficiently high, supply to the apparatus can be performed smoothly during melt kneading, and handling during transportation is easy. The shape of the chip can be various shapes such as a cylindrical shape, a quadrangular prism shape, and a spherical shape.

<Polytrimethylene terephthalate (B)>
The present invention includes polytrimethylene terephthalate (B) (hereinafter sometimes abbreviated as “PTT (B)”). PTT (B) can be used as a master chip when manufacturing PTT (A).
PTT (B) is mainly composed of trimethylene terephthalate units, and has an intrinsic viscosity (measured in an o-chlorophenol solution at 35 ° C.) of 0.5 to 1.6 dL / g, exceeding 0.5% by weight. 30% by weight or less of the compound represented by the above formula (I) and / or the compound represented by the above formula (II) is contained.
PTT (B) is the same as PTT (A) except that the content of the compound represented by the above formula (I) and / or the compound represented by the above formula (II) is larger than that of PTT (A). . The content of the compound represented by the formula (I) or (II) in the PTT (B) is preferably 1 to 20% by weight.
The shape of PTT (B) is preferably a chip-like shape similar to PTT (A). This shape is preferable in terms of smooth supply to the apparatus during melt-kneading and easy handling during transportation. PTT (B) can be produced by the same method as PTT (A) except that the amount of the compound represented by the above formula (I) and / or the compound represented by the above formula (II) is different.

<Masterbatch method>
PTT (A) can be produced by a so-called master batch method using PTT (B). That is, PTT (A) is mainly composed of trimethylene terephthalate units and has an intrinsic viscosity (measured in an o-chlorophenol solution at 35 ° C.) of 0.5 to 1.6 dL / g of polytrimethylene terephthalate (C) ( Hereinafter, it may be produced by melting and kneading the PTT (B) at a ratio of 0.5 to 20 parts by weight with respect to 100 parts by weight of the powder (which may be abbreviated as “PTT (C)” hereinafter).
Here, PTT (C) is the same polyester as PTT (A) or PTT (B) except that it does not contain the compound represented by formula (I) or (II). PTT (C) can be produced by the same method as PTT (A) or PTT (B) except that the compound represented by formula (I) or (II) is not added.

The melt kneading can be performed using a melt extruder or the like after blending a base chip made of PTT (C) and a master chip made of PTT (B) in a dryer or the like. The master chip and the base chip may be kneaded after being melted using separate melt extruders. The base chip may be melted and kneaded by supplying a master chip after the base chip is melted in a melt extruder or a batch type melting kettle. The melt kneading temperature is preferably 250 to 270 ° C. The pressure at the time of melt kneading may be a normal pressure, but in order not to lower the intrinsic viscosity, it is preferable to melt knead under reduced pressure. Under reduced pressure is preferably 100 Pa or less, more preferably 80 Pa or less. Thus, a melt extruder having a suction port that can be connected to a pump in order to perform melt kneading under reduced pressure can also be used.
If the amount of PTT (B) relative to PTT (C) is small, uniform dispersion is difficult to obtain. On the other hand, when the amount is too large, the amount of the master chip used is increased, and as a result, the amount of the compound represented by formula (I) or (II) increases, which is not preferable. The amount of the master chip is particularly preferably 1 to 10 parts by weight with respect to 100 parts by weight of the base chip.

<Fiber>
Furthermore, PTT (A) can manufacture a fiber by a conventionally well-known method. For example, PTT (A) can be produced by melt spinning at 240 ° C. to 280 ° C. at a speed of 400 to 5,000 m / min. When the spinning speed is in this range, the polyester fiber obtained has sufficient strength and can be wound stably.
The drawing can be continuously processed after winding the fiber or without winding it once. By this treatment operation, a drawn yarn can be obtained. Further, the obtained polyester fiber is preferably subjected to an alkali weight reduction treatment in order to enhance the texture.

Moreover, the cyclic dimer content in the fiber obtained from the PTT (A) of the present invention is preferably 0.01 to 2.5% by weight. When the cyclic dimer content is in this range, it becomes difficult to cause staining spots or the like in the dyeing process. The cyclic dimer content is more preferably 0.01 to 1.5% by weight. In order to reduce the cyclic dimer content in this fiber, it is effective to shorten the residence time from melting PTT (A) to spinning, preferably 20 minutes or less.
There is no restriction | limiting about the shape of the nozzle | cap | die used at the time of spinning, and any of circular, irregular shape, solid, hollow etc. can be employ | adopted.

  In addition, the chip | tip of PTT (A) and the fiber obtained from this are a small amount of additives as needed, for example, a lubricant, a pigment, dye, antioxidant, a solid phase polycondensation accelerator, a fluorescent whitening agent, an antistatic agent. , An antibacterial agent, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a light-shielding agent, or a matting agent. In particular, titanium oxide as a matting agent is preferably added, and the titanium oxide preferably contains 0.01 to 10% by weight of titanium oxide having an average particle size of 0.01 to 2 μm in PTT (A). .

  The fiber obtained from the PTT (A) of the present invention can be made into a dyed yarn through the steps of general scouring, dyeing, alkali reduction washing, finishing agent treatment, dehydration and drying. As the dyeing form, general cheese dyeing or case dyeing is preferably employed. The dye is preferably an easily alkali-decomposable disperse dye and dyed at 110 to 120 ° C. under high temperature and pressure. Further, the fiber of the present invention is an easily dyeable fiber, and the dyeing start temperature is about 20 ° C. lower than that of a general polyethylene terephthalate fiber, and the heating rate is suppressed to about 50% from the viewpoint of preventing dyeing spots. Preferably it is done.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to these examples. In addition, each value in an Example was measured by the method of the following description.
(1) Intrinsic viscosity:
The intrinsic viscosities of polytrimethylene terephthalate and fiber were determined from the viscosity values measured at 35 ° C. in an orthochlorophenol solution.
(2) Amount of dipropylene glycol:
A polytrimethylene terephthalate sample was sealed with an excess amount of methanol and subjected to methanol decomposition in an autoclave at 260 ° C. for 4 hours. The decomposition product was gas chromatographed (HP6890 Series GC System, manufactured by HEWLETT PACKARD) to determine the amount of dipropylene glycol, and the weight percentage of dipropylene glycol based on the measured polymer weight was determined.
(3) Cyclic dimer content:
An apparatus in which two Waters GPC columns TSKgel G2000H8 were connected to a Waters 486 type liquid chromatograph was used. Chloroform is used as a developing solvent, a polytrimethylene terephthalate sample (1 mg) is dissolved in 1 ml of hexafluoroisopropanol, and a sample diluted to 10 ml with chloroform is injected. The weight percentage in the polymer is obtained from a standard cyclic dimer calibration curve. It was.
(4) Cyclic dimer formation rate:
The polytrimethylene terephthalate chip was remelted at 260 ° C. in a nitrogen atmosphere and held for 20 minutes. Thereafter, the cyclic dimer content before and after remelting was analyzed to determine the production rate.

(5) Color b ^* value after crystallization:
The polytrimethylene terephthalate chip was measured after drying at 140 ° C. for 2 hours. About the hue of the fiber, it measured about the meliath knitted fabric using the Minolta color difference meter (model | form: CR-200).
(6) Measurement of calcium content, phosphorus content, cobalt content:
A polytrimethylene terephthalate sample was heated and melted to prepare a circular disk, which was quantified using a fluorescent X-ray apparatus ZSX100e type manufactured by Rigaku Corporation.
(7) Quantification of content of phosphonate compound and the like:
A polytrimethylene terephthalate sample was dissolved in a deuterated trifluoroacetic acid / deuterated chloroform = 1/1 mixed solvent, and then JEOL A-600 superconducting FT-NMR manufactured by JEOL Ltd. was used for nuclear magnetic resonance spectrum ( < ¹ > H-NMR) was measured. The phosphonate compound content was quantified from the spectrum pattern according to a conventional method.

(8) Determination of polyester-soluble titanium metal element:
A polytrimethylene terephthalate sample was dissolved in orthochlorophenol and extracted with 0.5 N hydrochloric acid. The extract was quantified using a Hitachi Z-8100 atomic absorption spectrophotometer. Here, when dispersion of an inorganic titanium compound not dissolved in polyester such as titanium oxide was confirmed in the extract after extraction with 0.5 N hydrochloric acid, titanium oxide particles were precipitated with a centrifuge. Next, only the supernatant was recovered, and the recovered liquid was quantified using an atomic absorption photometer. This operation makes it possible to quantify titanium elements that are soluble in polyester.
(9) Tensile strength and tensile elongation of fiber:
Measurement was performed in accordance with the method described in JIS L1013-1992. That is, using a tensile tester (manufactured by Shimadzu Corporation, Autograph (AG-E type)), a tensile test was performed under the conditions of a fiber sample length of 25 cm and an elongation rate of 20 cm / min. The tensile strength and tensile elongation of the fiber were determined from the load and elongation at the maximum yield point.

Example 1
A mixture of 100 parts by weight of dimethyl terephthalate and 70.5 parts by weight of trimethylene glycol was charged with 0.053 parts by weight of tetra-n-butyl titanate in a reactor equipped with a stirrer, a rectifying column and a methanol distillation condenser. It is. While the temperature of the reactor was gradually raised from 140 ° C., transesterification was performed while distilling out the methanol produced as a result of the reaction out of the system. Three hours after the start of the reaction, the internal temperature of the reactor reached 210 ° C.
Subsequently, the obtained reaction product is transferred to another reactor equipped with a stirrer and a glycol distillation condenser, and the internal temperature of the reactor is gradually raised from 210 ° C. to 265 ° C., and from normal pressure to 70 Pa. The polymerization reaction was carried out while lowering the pressure to a high vacuum. While tracing the melt viscosity in the reactor, the polymerization reaction was terminated when the intrinsic viscosity reached 0.65 dL / g. Thereafter, 0.106 parts by weight of CDHMP (trade name: Irganox 1425, manufactured by Ciba Specialty Chemicals) was added and melt-kneaded for 15 minutes.
Here, CDHMP is calcium diethylbis (((3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl) methyl) phosphonate) (alias: calcium bis {ethyl ((3,5-bis ( 1,1-dimethylethyl) -4-hydroxyphenyl) methyl) phosphonate}). This compound is a compound in which R ₁ = R ₂ = t-butyl group, R ₃ = ethyl group, n = 1, m = 2, and M = Ca in the formula (I).
The molten polymer was extruded into cooling water in the form of a strand from the bottom of the reactor and cut into chips by using a strand cutter.

The obtained chip was pre-crystallized at 120 ° C. for 4 hours and then charged into a tumbler type solid phase polymerization apparatus. In a nitrogen atmosphere, the solid phase polymerization apparatus was heated to 200 ° C., and then subjected to a solid phase polymerization reaction under a high vacuum of 70 Pa for about 14 hours. A chip having an intrinsic viscosity of 0.93 dL / g was obtained.
The obtained chip was further dried at 120 ° C. for 4 hours, and then the obtained chip was melted at 260 ° C. using an extrusion spinning machine having a spinneret provided with 36 circular spinning holes having a hole diameter of 0.27 mm and discharged. An undrawn yarn was obtained by spinning at an amount of 34 g / min and a take-up speed of 2,400 m / min. The obtained undrawn yarn was subjected to a drawing treatment machine having a heating roller at 60 ° C. and a plate heater at 160 ° C., and drawn at a draw ratio of 1.7 times to obtain 83 dtex / 36 filament fibers.
The evaluation results of the obtained chips and fibers are shown in Tables 1 and 2.

Example 2
In Example 1, melt polymerization and solid phase polymerization were performed without adding CDHMP to obtain a chip having an intrinsic viscosity of 0.98 dL / g. This chip was remelted at 260 ° C. using a twin screw extruder, and then CDHMP was added from the side feeder while adjusting the content to be 0.1% by weight. Then, it cut | disconnected again using the strand cutter, and obtained the chip | tip with an intrinsic viscosity of 0.93 dL / g. The obtained chip was made into a fiber in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2.

Example 3
In Example 1, melt polymerization and solid phase polymerization were performed without adding CDHMP to obtain a chip having an intrinsic viscosity of 0.93 dL / g. To 100 parts by weight of the obtained chip, 21.2 parts by weight of a 5% by weight CDHMP dichloromethane solution was sprayed uniformly and dried at room temperature in a nitrogen stream. The obtained chip was made into a fiber in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2.

Comparative Example 1
In Example 1, it carried out similarly except not having added CDHMP. The evaluation results are shown in Tables 1 and 2.

DPG: Dipropylene glycol content CD: Cyclic dimer content

  CD: Cyclic dimer content

Reference Example 1 (Manufacture of base chip)
A mixture of 100 parts by weight of dimethyl terephthalate and 70.5 parts by weight of trimethylene glycol and 0.053 parts by weight of tetra-n-butyl titanate were charged into a reactor equipped with a stirrer, a rectifying column and a methanol distillation condenser. It is. While the temperature of the reactor was gradually raised from 140 ° C., transesterification was performed while distilling out the methanol produced as a result of the reaction out of the system. Three hours after the start of the reaction, the internal temperature of the reactor reached 210 ° C.
Subsequently, the obtained reaction product is transferred to another reactor equipped with a stirrer and a glycol distillation condenser, and the internal temperature of the reactor is gradually raised from 210 ° C. to 265 ° C., and from normal pressure to 70 Pa. The polymerization reaction was carried out while lowering the pressure to a high vacuum. While tracing the melt viscosity in the reactor, the polymerization reaction was terminated when the intrinsic viscosity reached 0.65 dL / g. The molten polymer was extruded into cooling water in the form of a strand from the bottom of the reactor and cut into chips by using a strand cutter.
The obtained chip was pre-crystallized at 120 ° C. for 4 hours and then charged into a tumbler type solid phase polymerization apparatus. In a nitrogen atmosphere, the solid phase polymerization apparatus was heated to 200 ° C. and then subjected to a solid phase polymerization reaction under a high vacuum of 70 Pa. Then, when the intrinsic viscosity reached 0.93 dL / g, the polymerization reaction was terminated to obtain a base chip (hereinafter abbreviated as “base chip”).

Example 4 (Manufacture of master chip)
The base chip obtained in Reference Example 1 was dried at 120 ° C. for 4 hours and then supplied to a vented twin-screw extruder (manufactured by Kobe Steel; KTX-46). The temperature of the kneading part of the twin screw extruder was set to 265 ° C., and CDHMP was melt kneaded at a residence time of 5 minutes so that the ratio shown in Table 3 was obtained. The obtained polymer was extruded in the form of strands into cooling water and cut using a strand cutter to obtain a master chip (hereinafter abbreviated as “master chip”). The evaluation results are shown in Table 3.

Comparative Example 2
The same operation as in Example 4 was performed except that the content of CDHMP was adjusted to the ratio shown in Table 3. However, I could not get a master chip.

DPG: Dipropylene glycol content CD: Cyclic dimer content #: mmol% per total dicarboxylic acid component

Example 5 (Production by Masterbatch Method)
The base chip obtained in Reference Example 1 and the master chip obtained in Example 4 were chip-blended at the ratio shown in Table 4, dried at 120 ° C. for 4 hours, and then a twin screw extruder with a vent (Kobe Supplied to KTX-46). The temperature of the kneading part of the twin screw extruder was set to 265 ° C., and melt kneading was performed with a residence time of 5 minutes. The obtained polymer was extruded into cooling water in the form of a strand and cut using a strand cutter to obtain a chip.
The obtained chip was further dried at 120 ° C. for 4 hours, and then melted at 260 ° C. using an extrusion spinning machine having a spinneret provided with 36 circular spinning holes having a hole diameter of 0.27 mm, and a discharge amount of 34 g / min. The undrawn yarn was obtained by spinning at a take-up speed of 2,400 m / min. The obtained undrawn yarn was subjected to a drawing machine having a heating roller at 60 ° C. and a plate heater at 160 ° C., and drawn at a draw ratio of 1.7 times to obtain a drawn yarn of 83 dtex / 36 filaments. The evaluation results of the obtained chips and fibers are shown in Tables 4 and 5.

Comparative Example 3
The same operation as in Example 5 was performed except that the blend ratio was changed to the ratio shown in Table 4. The evaluation results of the obtained chip are shown in Table 4. The obtained chip was fiberized in the same manner as in Example 5. The results are shown in Table 5.

Example 6
The base chip obtained in Reference Example 1 and the master chip obtained in Example 4 were chip-blended at the ratio shown in Table 4.
Next, after drying at 120 ° C. for 4 hours, it was melted at 260 ° C. using an extrusion spinning machine having a spinneret provided with 36 circular spinning holes having a hole diameter of 0.27 mm, a discharge amount of 34 g / min, a take-up speed of 2, An undrawn yarn was obtained by spinning at 400 m / min. The obtained undrawn yarn was subjected to a drawing machine having a heating roller at 60 ° C. and a plate heater at 160 ° C., and drawn at a draw ratio of 1.7 times to obtain a drawn yarn of 83 dtex / 36 filaments. The evaluation results of the obtained polyester fiber are shown in Table 5.

Comparative Example 4
The same operation as in Example 6 was performed except that the blend ratio was changed to the ratio shown in Table 4. The evaluation results of the obtained chips and fibers are shown in Tables 4 and 5.

DPG: Dipropylene glycol content CD: Cyclic dimer content #: mmol% per total dicarboxylic acid component

  CD: Cyclic dimer content

Example 7
A polytrimethylene terephthalate chip (manufactured by Shell: Cortera CP50921P) having an intrinsic viscosity of 0.93 dL / g and a cyclic dimer content of 1.05% by weight is dried at 75 ° C. for 1 hour and then at 125 ° C. for 5 hours, and then a twin-screw extruder Was remelted at 260 ° C., and phenylphosphinic acid was added from the side feeder while adjusting the content to 0.1% by weight. A chip having an intrinsic viscosity of 0.93 dL / g was obtained. In the same manner as in Example 1, after that, the obtained chip was further dried at 120 ° C. for 4 hours, and then subjected to melt spinning and stretching treatment. The evaluation results are shown in Table 6.

CD: Cyclic dimer content #: mmol% per total dicarboxylic acid component

According to the present invention, there are provided polytrimethylene terephthalate having a low content of cyclic dimer and hardly causing the cyclic dimer to precipitate during melt molding, and a method for producing the same. Therefore, since there is little occurrence of yarn breakage at the time of spinning due to the occurrence of cyclic dimer at the time of melt molding, and a decrease in processing stability at the time of weaving / knitting, the PTT (A) of the present invention is a fiber, woven fabric, It is useful as a raw material for knitting.

Claims (8)

It consists mainly of trimethylene terephthalate units, has an intrinsic viscosity (measured at 35 ° C. in an o-chlorophenol solution) of 0.5 to 1.6 dL / g, 0.01 to 0.5% by weight of the following formula ( A polytrimethylene terephthalate (A) containing a compound represented by I) and / or a compound represented by the following formula (II).

[In the formula (I), R ₁ , R ₂ and R ₃ are the same or different and are hydrocarbon groups having 1 to 10 carbon atoms. Moreover, n is an integer of 1-5. M is an alkali metal atom or an alkaline earth metal atom. When M is an alkali metal atom, m = 1, and when M is an alkaline earth metal atom, m = 2. ]

[In formula (II), R ₄ and R ₅ are the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. ]   The polytrimethylene terephthalate according to claim 1, wherein the content of the cyclic dimer is 0.01 to 2% by weight.   The polytrimethylene terephthalate according to claim 1 or 2, wherein a regenerated cyclic dimer formation rate at 260 ° C in a nitrogen atmosphere is 0.01 wt% / min or less.   The amount of titanium metal element in the catalyst residue dissolved and contained in polytrimethylene terephthalate is 2 to 150 mmol% with respect to the total dicarboxylic acid component contained as a constituent component of the polytrimethylene terephthalate. 3. Polytrimethylene terephthalate according to any one of 3.   The main repeating unit consists of trimethylene terephthalate units, and the intrinsic viscosity (measured in o-chlorophenol solution at 35 ° C.) is 0.5 to 1.6 dL / g, more than 0.5% by weight and 30% by weight The polytrimethylene terephthalate (B) containing the following compound represented by the formula (I) according to claim 1 and / or the compound represented by the formula (II) according to claim 1.   It consists mainly of trimethylene terephthalate units and has an intrinsic viscosity (measured in an o-chlorophenol solution at 35 ° C.) of 0.5 to 1.6 dL / g of 100 parts by weight of polytrimethylene terephthalate (C). A process for producing a polytrimethylene terephthalate (A) comprising melt-kneading the polytrimethylene terephthalate (B) according to claim 5 of -20 parts by weight.   The terephthalic acid is esterified with trimethylene glycol or the ester-forming derivative of terephthalic acid is transesterified with trimethylene glycol and then polymerized to have an intrinsic viscosity of 0 (measured in an o-chlorophenol solution at 35 ° C.). In a process for producing a polytrimethylene terephthalate of .5 to 1.6 dL / g, a compound represented by the formula (I) according to claim 1 and / or a compound represented by the formula (II) according to claim 1 is prepared. A method for producing polytrimethylene terephthalate (A), wherein the polytrimethylene terephthalate (A) is added so that the content in the polytrimethylene terephthalate is 0.01 to 0.5% by weight. After the intrinsic viscosity of polytrimethylene terephthalate (measured in o-chlorophenol solution at 35 ° C.) becomes 0.4 dL / g or more, the compound represented by the above formula (I) and / or the above formula (II) A method for producing polytrimethylene terephthalate (A) according to claim 7, wherein a compound represented by the formula: