JP2008274079A - Method for producing modified polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a modified polyester suppressed in a heat decomposition reaction due to the catalyst used in the polymerization, therefore being good in a polymer hue as compared with a conventional product and reduced in a hue change with time when molten at an elevated temperature, reduced in fluff formation during warping, and having such excellent dyeability hardly generating uneven dyeing. <P>SOLUTION: The method is one for producing a modified polyester containing a titanium element and a phosphorus element by copolymerizing 0.1-10 mol%, based on the entire acid component, metal-sulfonate-group-containing isophthalic acid component with 0.1-5.0 wt.% polyoxyalkylene glycol component of an average molecular weight of 400-8,000, wherein a phosphorus (III) compound in an amount of 10-200 ppm in terms of the phosphorus element is added to the reaction system in the stage where the intrinsic viscosity (IV) reaches 85 to below 99% of the set of the IV of the modified polyester. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a modified polyester excellent in color tone and thermal stability. More specifically, the thermal decomposition reaction caused by the catalyst used at the time of polymerization is suppressed, the color tone of the polymer is better than that of the conventional product, the amount of change in color tone with time at high temperature melting is small, and the fluff and dyeing unevenness during aging The present invention relates to a method for producing a modified polyester that is less prone to generation of odor.

  Polyester is used for various purposes because of its useful functionality, and is used for clothing, materials, and medical use, for example. Among them, polyethylene terephthalate is excellent in terms of versatility and practicality and is preferably used.

  Polyethylene terephthalate is generally produced from terephthalic acid or its ester-forming derivative and ethylene glycol. However, in commercial processes for producing high molecular weight polymers, antimony compounds, germanium catalysts, titanium catalysts, etc. are widely used as polycondensation catalysts. It is used. These polycondensation catalysts naturally promote polycondensation reaction of polyethylene terephthalate, but also promote side reactions such as thermal decomposition reaction and oxidative decomposition reaction. In particular, in the case of using a titanium catalyst, since the catalytic activity is high, the side reaction is also greatly promoted, resulting in a problem that the polymer is colored yellow. It is not preferable that the polymer is yellowish, for example, when polyester is used as the fiber, since the commercial value of the fiber for clothing is impaired.

  In order to solve this problem, studies have been widely made to improve the color tone and heat resistance of a polymer by adding a phosphorus compound together with a polycondensation catalyst. This method suppresses the activity of the polycondensation catalyst with a phosphorus compound to improve the color tone and heat resistance of the polymer.

  In a polyester composition using a titanium compound as a catalyst, a polyester composition having excellent heat resistance has been proposed by specifying the amount of a titanium compound and a phosphorus compound, and further the amount of a magnesium compound, a manganese compound and a calcium compound (patent) Reference 1). However, although this method certainly has a certain effect on the suppression of side reactions, the addition of a certain amount or more of the phosphorus compound may suppress the polymerization activity of the polycondensation catalyst and may not reach the target degree of polymerization. In addition, the polymerization reaction time is delayed, resulting in a problem that the color tone of the polymer deteriorates.

  When producing a polyester composition using an antimony compound, a method for producing a polyester having excellent color tone and thermal stability by adding a phosphorus compound when the polycondensation reaction is completed 30 to 60% is disclosed (patent) Reference 2). However, although this method certainly has a certain effect in suppressing side reactions, the addition of a certain amount or more of a phosphorus compound at a stage of 30 to 60% results in excessive suppression of the polymerization activity of the polycondensation catalyst. In some cases, the degree of polymerization may not be reached, and the polymerization reaction time is delayed, resulting in a problem that the color tone of the polymer deteriorates.

  In a modified polyester that is copolymerized with isophthalic acid, polyethylene glycol, or the like, a method has been proposed in which a phosphorus compound is added after completion of a polycondensation reaction in order to solve the delay in the polymerization reaction due to the addition of the phosphorus compound (Patent Document 3). reference). In the continuous polymerization method, a method of adding a phosphorus compound after completion of the polycondensation reaction is disclosed (see Patent Document 4). Certainly, when these methods are used, deactivation of the polycondensation catalyst by the phosphorus compound can be prevented, but since the polyester and the phosphorus compound are mixed after the polycondensation reaction is completed, the side reaction that occurs immediately after the completion of the polycondensation reaction cannot be suppressed. Further, deterioration of the polymer in the mixing process is inevitable.

Therefore, in the present invention, as a result of diligent investigations to solve the above problems, after the addition of the catalyst, the pressure reduction of the polymerization reactor was started and before the polymerization reaction was substantially completed, specifically, the IV setting of the modified polyester was performed. It was found that the object of the present invention can be achieved by adding a trivalent phosphorus compound at a level of 85% or more and less than 99% of the value.
JP 2006-188667 A (Claims) JP-A-33-3748 (Claims) JP-A-48-79896 (Claims) JP 2000-510180 (Claims)

  The object of the present invention is to solve the above-mentioned conventional problems, that is, to suppress the thermal decomposition reaction caused by the catalyst used at the time of polymerization, the color tone of the polymer is better than the conventional product, and the color tone change amount with time at high temperature melting Furthermore, it is to provide a method for producing a modified polyester having excellent dyeability, which is less likely to cause fuzz and dyeing unevenness during production.

  The means of the present invention comprises 0.1 to 10 mol% of an isophthalic acid component containing a metal sulfonate group and 0.1 to 5.0 wt% of an average molecular weight of 400 to 8000 polyoxyalkylene glycol component based on the total acid component. In the method for producing a copolymerized modified polyester containing elemental titanium and elemental phosphorus, the trivalent phosphorus compound is converted to elemental phosphorus in terms of elemental phosphorus at a stage of 85% or more and less than 99% of the IV set value of the modified polyester. It can be achieved by a method for producing a modified polyester characterized by adding ~ 200 ppm.

  Compared to the modified polyester obtained by the conventional production method, the color tone of the polymer is good and the color tone change with time at the time of high-temperature melting can be reduced. This modified polyester not only solves problems such as a decrease in color tone in the production process for a molded product for fibers, but also can suppress the occurrence of fluff and dyeing unevenness during production, and has excellent dyeability. It relates to a modified polyester.

  The production method of the modified polyester composition according to the present invention is a production method in which dicarboxylic acid or an ester-forming derivative thereof and diol or an ester-forming derivative thereof are esterified or transesterified and then polycondensed. Specific examples of the modified polyester obtained by such a production method include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate. And polyethylene-1,2-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate. Among them, polyethylene terephthalate which is most widely used or a modified polyester copolymer mainly containing ethylene terephthalate units is preferable.

  Examples of the polyoxyalkylene glycol in the present invention include polyethylene glycol, polypropylene glycol, polybutylene glycol and the like. These polyoxyalkylene glycols may be used alone or in combination. From the viewpoint of the homogeneity of the obtained polyester, for example, polyethylene glycol is preferably used for a polyester whose main component is polyethylene terephthalate.

  The modified polyester according to the present invention contains 0.1 to 10 mol% of an isophthalic acid component containing a metal sulfonate group and 0.1 to 5.0 wt% of a polyoxyalkylene glycol having a weight average molecular weight of 400 to 8000. Copolymerize. When the copolymerization amount of isophthalic acid containing a metal sulfonate group is too large, the Δb value in the polymerization step is undesirably increased. On the other hand, if the amount is too small, the dyeability during yarn production is poor.

  If the weight average molecular weight of the polyoxyalkylene glycol is too large, no copolymerization occurs and a lump is easily formed in the polyester, and if it is too small, the dyeability is poor. If the copolymerization amount of polyoxyalkylene glycol is too large, the Δb value in the polymerization step becomes large, which is not preferable. If the amount is too small, the dyeability during yarn production is poor. The copolymerization amount of isophthalic acid containing a metal sulfonate group is preferably 0.6 to 5 mol%, and more preferably 1.0 to 3.0 mol%. The weight average molecular weight of the polyoxyalkylene glycol is preferably 800 to 2000, and the copolymerization amount is preferably 0.5 to 2.0% by weight.

  Coloring of polyester and deterioration of heat resistance are caused by a side reaction of polyester as clearly shown in a saturated polyester resin handbook (Nikkan Kogyo Shimbun, first edition, P.178-198). In the side reaction of this polyester, carbonyl oxygen is activated by a metal catalyst, and β hydrogen is extracted, thereby generating a vinyl end group component and an aldehyde component. By forming a polyene by this vinyl end group, the polymer is colored yellow, and since an aldehyde component is generated, the main chain ester bond is cleaved, so that the polymer has poor heat resistance. In particular, when a titanium compound is used as a polymerization catalyst, a side reaction caused by heat is strongly activated, so that many vinyl end group components and aldehyde components are generated, resulting in a yellow colored polymer having poor heat resistance. The phosphorus compound plays a role of regulating the activity of the polycondensation catalyst by appropriately interacting with the polycondensation catalyst. However, in the conventional method in which the phosphorus compound is added before the start of the polycondensation reaction, it is inevitable to reduce the polycondensation activity as well as the side reaction activity of the polycondensation catalyst. However, according to the present invention, it is possible to keep only the side reaction activity extremely small while sufficiently maintaining the polymerization activity of the polycondensation catalyst.

  Further, the present inventors have examined the coloring mechanism of the polyester in detail. As a result, the polycondensation reaction of the polyester is substantially completed in the β-hydrogen abstraction of the polyester and the reaction generated by the vinyl end group component and the aldehyde component. It was found that it occurred in large quantities immediately afterwards, and thereafter, a reaction in which a vinyl end group component was formed into polyene proceeded, and it was difficult to suppress even by addition of a phosphorus compound.

  Therefore, by adding a phosphorus compound not after the polycondensation reaction of the polyester is substantially completed but before the polycondensation reaction is substantially completed, the extraction of β hydrogen and the vinyl end groups that occur immediately after the completion of the polycondensation reaction are achieved. It has been found that the production of components and aldehyde components can be specifically suppressed. This cannot be achieved by the conventional phosphorus compound or the addition method of the phosphorus compound.

  In the present invention, the phosphorus compound is added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester. More preferably, it is between 90% and 97.5%, and particularly preferably between 92% and 96%. When the addition of the phosphorus compound is 99% or more of the point at which the polycondensation reaction is completed, the polymerization reactor is the same as the addition after the polymerization of the modified polyester is substantially completed due to the dispersion time of the phosphorus compound. Therefore, it becomes impossible to discharge stably and the chip shape becomes non-uniform, which may cause changes in physical properties and equipment troubles in the subsequent drying process or melting process, which is not preferable. If it is less than 85%, the polymerization reaction is delayed and the color tone of the polymer deteriorates, which is not preferable. The IV value of the modified polyester at the time when the phosphorus compound is added may be directly sampled and subjected to IV measurement by the method described later, but may be calculated from the torque load applied to the stirring blade of the reactor.

  The phosphorus compound according to the present invention may be added in several divided portions, or may be continuously added with a feeder or the like, but in the case of batch polycondensation, when adding a phosphorus compound, The phosphorus compound may be added alone, or may be added in a state dissolved or dispersed in a diol component such as ethylene glycol. However, if a diol component such as ethylene glycol is brought in and added in a large amount, depolymerization of the modified polyester (polyester main chain cleavage reaction) proceeds, so it is preferable to add the phosphorus compound alone.

  The phosphorus compound according to the present invention can be dissolved or melted in a polymerization system, and is preferably added in a capsule made of a polymer having substantially the same component as the polymer obtained in the present invention. When a phosphorous compound is added to the capsule as described above, addition to the polymerization reactor under reduced pressure condition prevents the phosphorus compound from scattering and flowing out to the decompression line. And a desired amount of phosphorus compound can be added to the polymer. The capsule referred to in the present invention is not limited as long as it contains phosphorus compounds, and includes, for example, an injection-molded container having a lid or a stopper, or a sheet or film formed into a bag shape by sealing or sewing. It is more preferable that the capsules make air vents such as holes. When a phosphorus compound is added to a capsule that has been ventilated and added to the polymerization reactor under vacuum conditions, the capsule bursts due to air expansion and the phosphorus compound flows out to the decompression line, or the upper part of the polymerization reactor. The phosphorus compound can be added to the polymer in a desired amount without adhering to the wall surface. If the capsule is too thick, it takes longer to dissolve and melt, so it is better to make the capsule thinner. However, the capsule should be thick enough not to burst during the encapsulation / addition operation of the phosphorus compound. For this purpose, a uniform and non-uniform thickness with a thickness of 10 to 500 μm is preferable.

  In the present invention, a trivalent phosphorus compound can be added at a stage of 45% or less of the IV set value of the modified polyester in order to suppress thermal degradation during the polycondensation reaction.

  The trivalent phosphorus compound refers to a phosphite compound, a phosphonite compound, a phosphinite compound, a phosphine compound, and an alkyl ester or aryl ester thereof. These trivalent phosphorus compounds convert peroxides (R—O—OH: further promoting side reactions) generated by side reactions into alcohols (R—OH) and turn themselves into pentavalent phosphorus compounds. This particularly suppresses the side reaction of the modified polyester.

  In the present invention, the phosphorus compound added between the start of the pressure reduction in the polymerization reactor after the addition of the polycondensation catalyst and before the polycondensation of the modified polyester is substantially completed has a melting point of 100 to 400 ° C. A range is preferable. When the melting point is 100 ° C. or lower, the phosphorus compound is scattered when the phosphorus compound is added under reduced pressure, and a desired amount of the phosphorus compound is not added to the modified polyester. The melting point of the phosphorus compound is preferably in the range of 115 to 350 ° C., and more preferably in the range of 175 to 300 ° C. so that the phosphorus compound does not scatter under reduced pressure conditions and is uniformly dispersed.

  Specific examples of the phosphorus compound added in the present invention include bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite (melting point: 234) represented by the following formula 1. ˜240 ° C.) and tris [2-{(2,4,8,10-tetra-t-butyldibenz [d, f] [1,3,2] -dioxaphosphine- 6-yl) oxy} ethyl] amine (melting point: 190-210 ° C.), 6- [3- (3-tert-butyl-4-hydroxy-5-methyl) propoxy] -2,4 represented by formula 3 , 8,10-tetra-t-butyldibenz [d, f] [1,3,2] -dioxaphosphine (melting point: 115 ° C. to 125 ° C.), tetrakis (2,4- Di-t-butyl-5-methylphenyl) [1,1- Phenyl] -4,4'-diyl bis phosphonite (mp: 234-240 ° C.) are preferred. In these compounds, Formula 1 is ADK STAB PEP-36 (manufactured by ADEKA Corporation), Formula 2 is IRGAFOS12 (manufactured by Ciba Specialty Chemicals), Formula 3 is Sumitizer GP (manufactured by Sumitomo Chemical Co., Ltd.), and Formula 4 is ( It is available as GSY-P101) manufactured by Osaki Industrial Chemical Co., Ltd. These compounds may be used alone or in combination.

  In the present invention, the trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester is 10 to 200 ppm in terms of phosphorus atoms with respect to the resulting modified polyester. It is preferable to add to the polyester to reduce the color tone of the modified polyester and the coloring in the production process of the molded product on a fiber, film, bottle or the like. If the addition amount is less than the above range, the desired effect will not be exhibited. If the addition amount is more than the above range, the phosphorus compound will not be sufficiently dispersed, so that it cannot be stably discharged from the polymerization reactor. Since the shape becomes non-uniform, it may cause a change in physical properties or equipment trouble in the subsequent drying process or melting process, which is not preferable. The amount of phosphorus added is preferably 12 to 150 ppm, more preferably 15 to 100 ppm.

  In the present invention, the trivalent phosphorus compound added at a stage of 45% or less of the IV set value of the modified polyester may be added to the modified polyester in an amount of less than 20 ppm in terms of phosphorus element. In order to reduce coloring in the manufacturing process of a molded product on a fiber, a film, a bottle or the like, it is preferable. When the amount is larger than the above-mentioned amount, the polymerization reaction is delayed, and the polymer color tone is deteriorated. The amount of phosphorus added is preferably 15 ppm or less, and more preferably 5 to 12 ppm in order to suppress thermal degradation of the modified polyester during the polymerization reaction.

  In the modified polyester according to the present invention, a titanium compound, an antimony compound, a germanium compound, an aluminum compound, or the like is used as a polycondensation catalyst. These polycondensation catalysts may be used alone or in combination, or in addition, compounds such as sodium, potassium, lithium, magnesium, calcium, zinc, cobalt and manganese may be used in combination. These polycondensation catalysts are preferably added in an amount of 1 to 1000 ppm in terms of metal atoms with respect to the resulting modified polyester. Among these, it is preferable to use a titanium compound as a polycondensation catalyst because generation of foreign matters is suppressed.

  The polycondensation catalyst of the present invention is generally a reaction in which a modified polyester is synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. (1) Reaction between a dicarboxylic acid component and a diol component (2) Transesterification reaction, which is a reaction between an ester-forming derivative component of dicarboxylic acid and a diol component, (3) Polyester terephthalate obtained after substantially completing the ester reaction or transesterification reaction This refers to a polycondensation reaction that increases the degree of polymerization of the low polymer by a dediol reaction, and has an effect that contributes to at least (3) the promotion of the reaction. Accordingly, titanium oxide particles generally used for fiber matting agents have substantially no catalytic effect on the above reaction, and can be used as a polycondensation catalyst of the present invention. Is different.

  When the polycondensation catalyst is a titanium compound, it is preferable to add 1 to 30 ppm in terms of titanium atoms with respect to the resulting modified polyester. When the content is 2.5 to 15 ppm, the thermal stability and color tone of the polymer are more preferable, and more preferably 4 to 10 ppm.

  The titanium compound used as the polymerization catalyst is preferably a titanium complex having a polyvalent carboxylic acid and / or hydroxycarboxylic acid and / or nitrogen-containing carboxylic acid as a chelating agent from the viewpoint of thermal stability and color tone of the polymer. Examples of chelating agents for titanium compounds include polyvalent carboxylic acids such as phthalic acid, trimellitic acid, trimesic acid, hemititic acid, pyromellitic acid, and hydroxycarboxylic acids such as lactic acid, malic acid, tartaric acid, and citric acid. As the nitrogen-containing carboxylic acid, ethylenediaminetetraacetic acid, nitrilotripropionic acid, carboxyiminodiacetic acid, carboxymethyliminodipropionic acid, diethylenetriaminopentaacetic acid, triethylenetetraminohexaacetic acid, iminodiacetic acid, iminodipropionic acid Hydroxyethyliminodiacetic acid, hydroxyethyliminodipropionic acid, methoxyethyliminodiacetic acid and the like. These titanium compounds may be used alone or in combination.

  The modified polyester according to the present invention may contain 0.01 to 7.0% by weight of titanium element in terms of titanium oxide, separately from the titanium compound used as a polymerization catalyst. When the titanium oxide particles are in this range, thermal decomposition during melting is difficult to occur, the polymer color tone is good, and the problem of foreign matter during molding does not occur. Preferably it is 0.5 to 2.0 weight%, More preferably, it is 1.2 to 1.8 weight%. The average particle size of the titanium oxide particles is 1.0 μm or less, and the integral ratio of the particles of 2.0 μm or more in the frequency distribution is 5% or less in the yarn process when the fibers are used. This is preferable from the viewpoint of reducing wear of guides and the like.

  In addition to particles such as silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, silicon, and carbon black, additives such as anti-coloring agents, stabilizers, antioxidants, etc. It can be contained.

  The melt polycondensation step in the method for producing a modified polyester according to the present invention is expected to have a more remarkable improvement effect in a batch system. In the case of a batch system, when the desired setting IV is reached, an inert gas is caused to flow into the reactor, the inside of the reactor is brought to normal pressure or pressure, the polycondensation reaction is stopped, and the reactor is discharged outside the reactor.

  The modified polyester to be used in the next process is assumed to have a Δb value of −2.5 to +2.5 when the difference between the b value collected at the beginning of the discharge process and the b value immediately before the end of the discharge process is the Δb value. Is preferred. Furthermore, the Δb value is preferably −2.0 to 2.0, particularly preferably −1.5 to 1.5. If it is within the above range, the color variation in the next process will be small, and quality trouble will not easily occur. If the above range is exceeded, quality troubles in the next process, for example, vertical stripes, occur. One specific example in which the Δb value is in the above range is 0.1 to 10 mol% of an isophthalic acid component containing metal sulfonate groups with respect to the total acid component, and 0.1 to 5 polyoxyalkylene glycol component having an average molecular weight of 400 to 8000. 0.03% by weight is copolymerized, and 10 to 200 ppm of a trivalent phosphorus compound is added in terms of phosphorus element at a stage where the IV setting value of the modified polyester is 85% or more and less than 99%.

  By using the modified polyester according to the present invention as a component of a fiber-forming polymer, synthetic fibers can be obtained within a range that has unprecedented high dyeing properties and does not impair the fiber properties of the fiber-forming polymer. Can do.

  In the present invention, examples of the fiber moldable polymer include polyesters such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. Preferably, it is a polyester composition mainly composed of polyethylene terephthalate, which is the most versatile as a synthetic fiber for clothing.

  Examples of the synthetic fiber include core-sheath type composite fiber, core-sheath type composite hollow fiber, sea-island type composite fiber, bonded type composite fiber, or blend fiber. It can be used as a component.

  Moreover, in the case of the synthetic fiber which mix | blended the modified polyester of this invention with the fiber-forming resin, the compounding ratio of the modified polyester of this invention shall be 3 to 95 weight% with respect to the total polymer amount. The lower limit of the blending ratio is set for the purpose of imparting sufficient dyeability, and the upper limit of the blending ratio is set from the viewpoint of preventing a decrease in spinnability and fiber physical properties.

  In order to obtain good dyeability in practical use, the dyeing exhaustion rate of the synthetic fiber is preferably as high as possible, 30% or more, further 40% or more, and particularly preferably 50% or more.

  In addition to the pigments such as titanium oxide and carbon black, conventionally known antioxidants, anti-coloring agents, anti-lighting agents, anti-static agents and the like may be added to the fiber-forming polymer.

  The cross-sectional shape of the synthetic fiber of the present invention is not limited to a round shape, but may be an irregular cross-section such as a triangular shape, a flat shape, or a multileaf shape. Further, the filamentous form of the synthetic fiber may be either a filament or a staple, and is appropriately selected depending on the application. The fabric form can be appropriately selected according to the purpose, such as woven fabric, knitted fabric, and non-woven fabric.

  Polyethylene terephthalate is usually produced by one of the following processes.

  That is, (A) a process in which terephthalic acid and ethylene glycol are used as raw materials, a low polymer is obtained by direct esterification reaction, and a high molecular weight polymer is obtained by subsequent polycondensation reaction, and (B) dimethyl terephthalate and ethylene glycol are used as raw materials. In this process, a low polymer is obtained by a transesterification reaction, and a high molecular weight polymer is obtained by a subsequent polycondensation reaction. Here, the esterification reaction proceeds even without a catalyst, but the aforementioned titanium compound may be added as a catalyst. In the transesterification reaction, a compound such as magnesium, manganese, calcium, cobalt, zinc, lithium, or the above-described titanium compound is used as a catalyst, and after the transesterification reaction is substantially completed, it is used for the reaction. For the purpose of inactivating the catalyst, a phosphorus compound may be added. In addition, the phosphorus compound added at this time is completely different from the phosphorus compound added in the present invention.

  The modified polyester according to the present invention can be added to the low polymer obtained in any stage of the series of reactions (A) or (B), preferably in the first half of the series of reactions (A) or (B). After adding the above-mentioned titanium compound, antimony compound, and germanium compound as an isophthalic acid containing acid base, polyethylene glycol, titanium oxide, and a polycondensation catalyst, the polycondensation reaction is started by reducing the pressure in the reactor. At this time, a trivalent phosphorus compound is added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester to obtain the target polyethylene terephthalate. This reaction can be applied to a batch, semi-batch or continuous mode.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the physical-property value in an Example was measured with the following method.
(1) Intrinsic viscosity of polymer IV
Measurement was performed at 25 ° C. using orthochlorophenol as a solvent.
(2) Color tone of polymer The color tone was measured as a Hunter value (L, a, b value) using a color difference meter (SM color computer model SM-T45, manufactured by Suga Test Instruments Co., Ltd.).
(3) Median b value of polymer The polymer b value sampled at a time equivalent to half of the weight in the discharge process is defined as the median b value. For example, when discharging 1 ton of polymer, the polymer at the time of 500 kg is sampled. The color tone was measured by the method described in (2).
(4) Δb value of polymer The difference between the b value of the polymer collected at the beginning of the discharge process and the b value immediately before the end of the process is taken as the Δb value. The color tone was measured by the method described in (2).
(5) Content of Titanium Element, Phosphorus Element, Antimony Element, etc. in Polymer It was determined with a fluorescent X-ray elemental analyzer (manufactured by Horiba, Ltd., MESA-500W type). X-ray fluorescence analysis was performed after the following pretreatment.
(6) Number of Fluffs Using a multipoint fluff counting device MFC-120 (manufactured by Toray Engineering Co., Ltd.), the number of fluffs counted at a yarn speed of 500 m / min for 100 minutes was measured.

In addition, it can be said that it is an excellent polymer when this value is 0.2 piece / 10 million meters or less.
(7) Warps The tubular knitted fabric was confirmed visually. Judgment criteria were x when the meridians were conspicuous and there was no commercial value, △ when the meridians were conspicuous but had commercial value, and ◯ when the meridians were not recognized.
(8) Dye exhaust rate In a 120 ° C hot water solution with a bath ratio of 1: 100, malachite green (manufactured by Kanto Chemical) 5% 0 wf, acetic acid 0.5 ml / l, sodium acetate 0.2 g / l Dyeing was performed for 60 minutes, and the dye exhaust rate of the tubular knitted fabric was determined from the difference in dyeing concentration in the liquid before and after dyeing.

  In addition, if this value is larger than 30%, it can be said that the polymer has excellent dyeability.

Example 1
About 100 kg of bis (hydroxyethyl) terephthalate is charged in advance, 82.5 kg of high-purity terephthalic acid (manufactured by Mitsui Chemicals) and ethylene glycol are added to an esterification reaction tank maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa. (Manufactured by Nippon Shokubai Co., Ltd.) 35.4 kg of slurry was sequentially supplied over 4 hours, and after completion of the supply, an esterification reaction was carried out over an additional hour, and 101.5 kg of the resulting esterification reaction product was polycondensed. Transferred to. The IV of this esterification-reactive organism was 0.3.

  5 g of silicon (manufactured by Toshiba Silicone Co., Ltd., TSF433) was added to the esterification reaction product. After stirring for 5 minutes, 11.5 g of cobalt acetate (30 ppm in terms of cobalt atom relative to the polymer), 15 g of manganese acetate (33 ppm in terms of manganese atom relative to the polymer), pentaerythritol-tetrakis (3- (3,5- G t-butyl-4-hydroxyphenol) propionate) (Ciba Geigy Co., Ltd., Irganox 1010) 75 g, lithium acetate 45 g, 5 ppm equivalent citrate chelate titanium compound in terms of titanium atom, When it reached 43%, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite (made by ADEKA) equivalent to 100 ppm (10 ppm in terms of phosphorus atom) with respect to the polymer Adeka Stub PEP-36) ethylene glycol It was added a mixture of slurry. After further stirring for 5 minutes, 1 kg of polyethylene glycol having a weight average molecular weight of 1000 (manufactured by Sanyo Chemical Industries, Ltd.) was added so that the amount of copolymerization with the polymer would be 1% by weight. After further stirring for 5 minutes, an ethylene glycol solution of 5-sodium sulfoisophthalic acid hydroxyethyl ester (manufactured by Takemoto Yushi Co., Ltd., ES-740) was added so that the content with respect to the polymer was 1.78 mol%. . After further stirring for 5 minutes, ethylene glycol slurry of titanium oxide particles was added to the polymer so that the amount was 1.5% by weight in terms of titanium oxide particles, and then the reaction was conducted while stirring the low polymer at 30 rpm. The system was gradually heated from 250 ° C. to 290 ° C., and the pressure was reduced to 40 Pa.

When 95% of the predetermined agitation torque (IV set value) is reached (2 hours and 15 minutes from the start of decompression), 250 ppm (25 ppm in terms of phosphorus atom) equivalent to the polymer from the top of the reaction can Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite (manufactured by ADKA, ADK STAB PEP-36, melting point 236 ° C., polyethylene terephthalate in advance by injection molding to a thickness of 200 μm Then, a container having an internal volume of 50 cm ^{3 and} a container molded in its lid (packed in a container and a lid having a combined weight of 30 g) were added. Thereafter, the reaction is continued, and when the predetermined stirring torque is reached, the reaction system is purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged into a strand, cooled, and immediately cut to obtain polymer pellets. It was. The time from the start of decompression to the arrival of the predetermined stirring torque was 2 hours and 25 minutes.

  The obtained polymer had a b-value center value of 7.0 and a Δb value of 1.5. The obtained polymer was subjected to the next step as it was, vacuum-dried at 150 ° C. for 12 hours, then melted in a melter with a spinning machine, then discharged from the spinning pack portion and taken up at a speed of 1000 m / min. The obtained undrawn yarn was drawn 2.8 times at 80 ° C. and then heat-set with a roller (125 ° C.) to obtain a drawn yarn of 83.3 dtex 36 filaments.

  Using a multi-point fluff counting device MFC-120 (manufactured by Toray Engineering Co., Ltd.), when the number of fluffs counted in a yarn speed of 500 m / min and 100 minutes was measured, the number of fluffs was 0.14 per 10 million meters. Yes, the quality was good.

  A cylindrical knitted fabric was knitted from this yarn by a 27 gauge sock knitting machine (manufactured by Eiko Sangyo Co., Ltd.). Next, this was boiled and refined for 5 minutes with boiling water containing 0.2% nonionic active agent (Granup CS, Sanyo Kasei Co., Ltd.) and 0.2% soda ash, washed with water and dried. . This tubular knitted fabric had a dye exhaustion rate of 62%, no warps were observed, and it was a good quality polymer.

Examples 2-5
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the addition time of the trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester was changed. The obtained polymer was excellent in color tone, and had good spinnability and dyeability.

Examples 6-11
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the amount of the trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester was changed. The obtained polymer was excellent in color tone, and had good spinnability and dyeability.

Examples 12-14
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the addition amount of the trivalent phosphorus compound added at a stage of 45% or less of the IV set value of the modified polyester was changed. The obtained polymer was excellent in color tone, and had good spinnability and dyeability.

Examples 15-24
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the copolymerization amount of 5-sodium sulfoisophthalic acid hydroxyethyl ester and the weight average molecular weight and copolymerization amount of polyalkylene glycol were changed. The obtained polymer was excellent in color tone, and had good spinnability and dyeability.

Examples 25-27
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the type of trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester was changed. The obtained polymer was excellent in color tone, and had good spinnability and dyeability.

Examples 28-35
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the type and amount of the polymerization catalyst were changed. The obtained polymer was excellent in color tone, and had good spinnability and dyeability.

Comparative Example 1
The modified polyester was polymerized and spun in the same manner as in Example 1 except that the polymerization reaction was carried out without adding the trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester. Stained. The obtained polymer had a large Δb value and was poor in spinnability and dyeability.

Comparative Example 2
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the trivalent phosphorus compound was added at a stage of 60% of the IV set value of the modified polyester. Since the trivalent phosphorus compound was added quickly, the polymerization catalyst was deactivated and the target IV was not reached.

Comparative Examples 3 and 4
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the addition amount of the trivalent phosphorus compound added at a stage of 45% or less of the IV set value of the modified polyester was changed. Since the addition amount of the trivalent phosphorus compound was large, the polymerization catalyst was deactivated and the target IV was not reached.

Comparative Example 5
The modified polyester was polymerized in the same manner as in Example 1 except that the addition amount of the trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester was changed. However, it was considered that the dispersibility of the phosphorus compound was insufficient, and ejection was not possible.

Comparative Examples 6-11
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the copolymerization amount of the isophthalic acid component containing a metal sulfonate group and the weight average molecular weight and copolymerization amount of the polyalkylene glycol were changed. In Comparative Examples 6, 8, and 11, the obtained polymers were excellent in color tone and had good spinnability, but the dyeability was insufficient. In Comparative Examples 7 and 9, the obtained modified polyester was excellent in dyeability, but was poor in color tone and spinnability. In Comparative Example 10, it was considered that the dispersibility of the phosphorus compound was insufficient, and ejection was not possible.

Comparative Examples 12 and 13
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the trivalent phosphorus compound was added after the polymerization reaction was substantially completed (after reaching the predetermined target IV). In Comparative Example 12, discharge was performed 0.25 seconds after the addition of the trivalent phosphorus compound. In Comparative Example 13, after reaching the predetermined target IV, the valve of the distilling tube was closed, the system of the polymerization reactor was kept under reduced pressure, the phosphorus compound was added, and the mixture was stirred for 10 minutes and then discharged. I did it. In Comparative Example 12, foreign matters that appeared to be aggregates of phosphorus compounds were generated in the polymer, an increase in low pressure was observed during melt spinning, and fluff was frequently generated. Further, in Comparative Example 13, the obtained polymer was inferior in color tone and was poor in spinnability and dyeability.

Comparative Examples 14-16
The modified polyester was polymerized, spun and dyed in the same manner as in Example 1 except that the type of trivalent phosphorus compound added at a stage of 85% or more and less than 99% of the IV set value of the modified polyester was changed. Since the added phosphorus compound was pentavalent, the obtained polymer was a polymer having a large Δb value and poor spinnability and dyeability.

Claims (7)

  Titanium element obtained by copolymerizing 0.1 to 10 mol% of isophthalic acid component containing a metal sulfonate group and 0.1 to 5.0 wt% of an average molecular weight of 400 to 8000 polyoxyalkylene glycol component with respect to the total acid component And a phosphorous element-containing modified polyester, wherein a trivalent phosphorus compound is added in an amount of 10 to 200 ppm in terms of phosphorus element at a stage of 85% or more and less than 99% of the IV set value of the modified polyester. The manufacturing method of the modified polyester characterized by the above-mentioned.   The modified polyester according to claim 1, wherein a trivalent phosphorus compound is added to the modified polyester in an amount of 45% or less of the IV set value of the modified polyester, and less than 20 ppm in terms of phosphorus element. Production method.   3. The method for producing a modified polyester according to claim 1, wherein the titanium element is 0.01 to 7.0% by weight in terms of titanium oxide.   The method for producing a modified polyester according to any one of claims 1 to 3, wherein the melting point of the trivalent phosphorus compound is 100 to 400 ° C.   The trivalent phosphorus compound is bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, tris [2-{(2,4,8,10-tetra-t-butyldibenz [ d, f] [1,3,2] -dioxaphosphin-6-yl) oxy} ethyl] amine, 6- [3- (3-tert-butyl-4-hydroxy-5-methyl) propoxy] -2,4,8,10-tetra-t-butyldibenz [d, f] [1,3,2] -dioxaphosphine, tetrakis (2,4-di-t-butyl-5-methylphenyl) The method for producing a modified polyester according to any one of claims 1 to 4, which is at least one selected from [1,1-biphenyl] -4,4'-diylbisphosphonite.   When adding the trivalent phosphorus compound at a stage where the IV setting value of the modified polyester is 85% or more and less than 99%, the trivalent phosphorus compound is added in a container mainly composed of polyester. The method for producing a modified polyester according to any one of claims 1 to 5.   The method for producing a modified polyester according to any one of claims 1 to 6, wherein the melt polycondensation step is a batch type.