JP4181002B2 - Split polyester composite fiber - Google Patents

Description

  The present invention relates to a split polyester composite fiber having a fiber cross-sectional shape in which one component is divided into a plurality of parts by the other component. More specifically, the present invention relates to a split-type polyester composite fiber having the performance that even if it is continuously spun through a spinneret for a long period of time, the amount of deposits on the die is very small and the moldability is excellent. Alternatively, the present invention relates to a split-type polyester composite fiber that can easily and efficiently provide an ultrafine polyester fiber by treating with hot water, and can reduce heavy metal components contained in alkaline drainage.

  Conventionally, split-type composite fibers arranged so that an alkali-soluble component is divided into a plurality of alkali-poorly soluble components (or alkali-insoluble components) are obtained by removing the alkali-soluble components, It is widely known that ultrafine fiber yarns can be obtained and that a fabric exhibiting a silk-like texture can be obtained by alkali treatment after the composite fiber is made into a fabric (for example, Patent Documents 1, 2, and 3). 4).

  In addition, the ultra-fine polyester fiber obtained by such a method has excellent properties such as high melting point, high strength, high Young's modulus, good electrical properties, chemical resistance, etc. It is expected to be used in sports apparel, filters, other apparel, and industrial fields.

  On the other hand, polyesters represented by polyethylene terephthalate are widely used for fibers, films, and other molded articles because of their excellent mechanical, physical, and chemical performances. Here, it is well known that the reaction rate and the quality of the resulting polyester are greatly affected by the type of catalyst used in the polycondensation reaction stage of the polyester. As a polycondensation reaction catalyst of polyethylene terephthalate, an antimony compound is most widely used because it has excellent polycondensation reaction catalyst performance and a polyester having good color tone can be obtained.

  However, when such split-type composite fibers are produced using polyester, foreign matter (hereinafter sometimes simply referred to as a base deposit) is deposited and deposited around the base hole when melt spinning is performed continuously over a long period of time. However, a bending phenomenon (bending) of the molten polymer flow occurs, and this causes a problem of formability that fuzz and / or yarn breakage occurs in the spinning and drawing processes.

  As a polycondensation reaction catalyst other than the antimony compound, it has also been proposed to use a titanium compound such as titanium tetrabutoxide. However, when such a titanium compound is used, it is caused by deposits on the die as described above. However, there is a new problem that the obtained polyester itself is colored yellow and the heat stability of the melt is poor.

  In order to solve the above-mentioned coloring problem, it is generally performed to add a cobalt compound to polyester to suppress yellowing. Certainly, the color tone (b value) of the polyester can be improved by adding the cobalt compound, but the problem that the addition of the cobalt compound decreases the melt heat stability of the polyester and the polymer tends to decompose. There is.

  In addition, as other titanium compounds, titanium hydroxide is used as a catalyst for polyester production (for example, see Patent Document 5), and α-titanic acid is used as a catalyst for polyester production (for example, see Patent Document 6). It is disclosed. However, in the former method, powdering of titanium hydroxide is not easy. On the other hand, in the latter method, α-titanic acid is easily changed in quality, so its storage and handling are not easy. In addition, it is difficult to obtain a polymer having a good color tone (b value).

  Further, a product obtained by reacting a titanium compound and trimellitic acid is used as a catalyst for producing a polyester (see, for example, Patent Document 7), and a titanium compound and a phosphite are reacted. The use of the obtained product as a catalyst for polyester production is disclosed (for example, see Patent Document 8).

  Certainly, according to these methods, although the melt heat stability of the polyester is improved to some extent, the color tone of the obtained polymer is not sufficient, and therefore further improvement of the polymer color tone is desired. In addition, the use of a catalyst obtained by reacting a titanium compound with a specific phosphonic acid compound is disclosed (for example, see Patent Document 9). Although this method greatly improves the color of the polymer, the improvement in heat resistance of the polyester has not yet reached a sufficient level.

JP 54-138620 A JP-A-1-162825 JP-A-5-9811 JP-A-8-109522 Japanese Patent Publication No. 48-2229 Japanese Patent Publication No. 47-26597 Japanese Patent Publication No.59-46258 JP 58-38722 A International Publication No. 01/00706 Pamphlet

  The object of the present invention is to solve the above-mentioned problems of the prior art, and even if the spinning is continuously performed for a long time through the spinneret, the amount of the deposit on the die is very small and the moldability is excellent. An object of the present invention is to provide a split polyester composite fiber having performance.

  Furthermore, another object of the present invention is to provide a polyester fiber having a very fineness easily and efficiently by treating the composite fiber with an alkaline aqueous solution or hot water.

［上記式中、Ｒ ^１ 、Ｒ ^２ 、Ｒ ^３ 及びＲ ^４ はそれぞれ同一若しくは異なって、アルキル基又はフェニル基を示し、ｍは１〜４の整数を表し、かつｍが２、３又は４の場合、２個、３個又は４個のＲ ^２ 及びＲ ^３ は、それぞれ同一であっても異なっていてもどちらでもよい。］

［上記式中、ｎは２〜４の整数を表わす。］

［上記式中、Ｒ ^５ 、Ｒ ^６ 及びＲ ^７ は、同一又は異なって炭素数原子数１〜４のアルキル基を表し、Ｘは、−ＣＨ _２ −又は―ＣＨ（Ｙ）を表す（Ｙは、ベンゼン環を示す）。］
更にポリエステル成分Ａとして、スルホイソフタル酸金属塩基を含む化合物を、ポリエステルを構成する全酸成分（スルホイソフタル酸金属塩基を含む化合物を含む。）を基準として１〜８モル％共重合した共重合ポリエステルに、さらに該ポリエステル成分Ａを基準として数平均分子量が４００〜３００００のポリオキシアルキレングリコールを１〜２０重量％、ヒンダードフェノール化合物を０．０２〜３重量％、及びアンチモン及びゲルマニウム金属元素量が２０重量ｐｐｍ以下を含有し、並びにジエチレングリコール単位が、ポリエステル成分Ａを基準として０．５〜５．０重量％共重合された共重合ポリエステル組成物を配し、
（２）該ポリエステル成分Ｂとしてエチレンテレフタレート単位を主たる繰り返し単位とするポリエステルを配する、
分割型ポリエステル複合繊維によって達成される。 As a result of intensive studies in view of the above prior art, the present inventors have completed the present invention.
That is, the object of the present invention is a composite fiber composed of a polyester component A and a polyester component B, the polyester component B has a fiber cross-sectional shape divided into a plurality by the polyester component A,
(1) From the product in which the polyester component A is reacted with a titanium compound represented by the following general formula (I) and an aromatic polyvalent carboxylic acid represented by the following general formula (II) or an anhydride thereof A catalyst system consisting essentially of an unreacted mixture of a titanium compound component containing at least one selected from the group consisting of 5 to 80 mmol% of a phosphorus compound represented by the following general formula (III) in terms of phosphorus element Polymerized,

[Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents an alkyl group or a phenyl group, m represents an integer of 1 to 4, and m is 2, 3, or 4] In this case, 2, 3 or 4 R ² and R ³ may be the same or different from each other. ]

[In the above formula, n represents an integer of 2 to 4. ]

[In the above formula, R ⁵ , R ⁶ and R ⁷ are the same or different and each represents an alkyl group having 1 to 4 carbon atoms, and X represents —CH ₂ — or —CH (Y) (Y represents Represents a benzene ring). ]
Further, as polyester component A , a copolymerized polyester obtained by copolymerizing 1 to 8 mol% of a compound containing a metal salt of sulfoisophthalic acid based on the total acid components (including compounds containing a metal salt of sulfoisophthalic acid) constituting the polyester. Further, based on the polyester component A, the polyoxyalkylene glycol having a number average molecular weight of 400 to 30000 is 1 to 20% by weight, the hindered phenol compound is 0.02 to 3% by weight, and the amounts of antimony and germanium metal elements are Containing a copolymerized polyester composition containing 20 ppm by weight or less and having a diethylene glycol unit copolymerized in an amount of 0.5 to 5.0% by weight based on the polyester component A;
(2) A polyester having an ethylene terephthalate unit as a main repeating unit is arranged as the polyester component B.
This is achieved by split polyester composite fibers.

  Furthermore, the other objective of this invention can be achieved by the ultrafine polyester fiber obtained by removing only the polyester component A in the above-mentioned composite fiber using alkaline aqueous solution and / or hot water.

  According to the present invention, it is possible to provide a split-type polyester composite fiber having the performance that even if it is continuously spun through a spinneret for a long time, the amount of the deposit on the die is very small and the moldability is excellent. . Moreover, an ultra fine fiber can be easily provided by performing alkali weight loss etc. to a composite fiber.

  The present invention will be described in detail below. The split type composite fiber of the present invention is a composite fiber composed of a polyester component A and a polyester component B, and the polyester component B has a fiber cross-sectional shape divided into a plurality of parts by the polyester component A.

  Here, the polyester component A is obtained by adding a polyoxyalkylene glycol having a number average molecular weight of 400 to 30,000 based on the polyester component A to a copolymer polyester obtained by copolymerizing 1 to 8 mol% of a compound containing a metal salt of sulfoisophthalic acid. 1 to 20% by weight, hindered phenol compound 0.02 to 3% by weight, and antimony and germanium metal element content is 20 ppm by weight or less, and diethylene glycol unit is 0.5 to 0.5% based on polyester component A It is a copolymerized polyester composition copolymerized by 5.0% by weight.

  Here, the polyester component A preferably comprises ethylene terephthalate as a main repeating unit, and is preferably a polyester to copolymerized polyethylene terephthalate. Here, “main” means 80 mol% or more of all repeating units. Further, the copolymerized polyester may be copolymerized with a small amount of components other than the sulfoisophthalic acid metal salt compound and polyoxyalkylene glycol, preferably 10 mol% or less.

  Here, the sulfoisophthalic acid metal base includes a group in which a lithium sulfonate group, a sodium sulfonate group, a potassium sulfonate group, or the like is bonded to an isophthalic acid group. -Lithium sulfoisophthalic acid, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, etc., and the compounds containing these metal salts of sulfoisophthalic acid are all acid components (sulfoisophthalic acid) constituting the copolymer polyester. 1-8 mol% copolymerization is required on the basis of a compound containing an acid metal base. When the copolymerization amount is less than 1 mol%, sufficient alkali weight loss cannot be obtained. On the other hand, when the content is more than 8 mol%, the melt viscosity is increased, a polymer having a high degree of polymerization cannot be obtained, the yarn breakage during spinning of the composite fiber is increased, and the process stability tends to deteriorate. It is. The copolymerization amount of the compound containing a metal salt of sulfoisophthalic acid is preferably in the range of 2 to 7 mol%, more preferably in the range of 3 to 6 mol%.

  Further, the copolymerized polyester composition used as the polyester component A needs to contain 1 to 20% by weight of polyoxyalkylene glycol having a number average molecular weight of 400 to 30,000. If the number average molecular weight of the polyoxyalkylene glycol is less than 400, a sufficient alkali weight loss rate cannot be obtained, and if it exceeds 30000, the cost increases.

  Further, when the content of the polyoxyalkylene glycol is less than 1% by weight, a sufficient alkali weight loss rate cannot be obtained, and when the content of the polyoxyalkylene glycol is more than 20% by weight, the heat resistance is lowered. Therefore, the yarn breakage during spinning of the composite fiber is increased, and the process stability tends to deteriorate.

  The polyoxyalkylene glycol may be simply contained without being bonded to the polyester component A through a covalent bond. However, since it is more preferable that the polyoxyalkylene glycol is copolymerized with the polyester component A, the number average molecular weight is 600 to 600. A range of 10,000 is preferred, and a range of 1000 to 6000 is even more preferred. The content of the polyoxyalkylene glycol is preferably 2 to 15% by weight, more preferably 3 to 10% by weight, when copolymerized.

  Here, specific examples of polyoxyalkylene glycol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, but polyethylene glycol is particularly preferred from the viewpoint of alkali weight loss rate.

  Furthermore, the copolymerized polyester composition used as the polyester component A needs to copolymerize 0.5 to 5.0% by weight of diethylene glycol units based on the polyester component A. The diethylene glycol unit referred to here is not a copolymer obtained by adding diethylene glycol during the production of the polyester component A, but a diethylene glycol component that occurs naturally in the production process of the polyester component A. In order to make it less than 5% by weight, it is necessary to extremely reduce the productivity of the polyester component A, which is not preferable because it is technically difficult and costly. On the other hand, if it exceeds 5.0% by weight, the yarn breakage at the time of spinning the composite fiber increases, and the process stability deteriorates. Moreover, the heat resistance of the obtained copolyester is also lowered. Preferably it is 0.7 to 4.5 weight%, More preferably, it is 1.0 to 4.0 weight%. In order to bring the copolymerization amount of diethylene glycol units in a polyester containing a compound containing a metal salt of sulfoisophthalate as in the present invention into this range, for example, an alkali metal salt of carboxylic acid is added to the total acid constituting the copolymer polyester. There is a method in which 20 to 500 mmol% is present based on the components. Specific examples of the alkali metal carboxylate include sodium acetate, potassium acetate, lithium acetate, sodium formate, potassium formate, and lithium formate.

  In addition, the copolymerized polyester composition used as the polyester component A needs to contain 0.02 to 3% by weight of a hindered phenol compound. Preferably it is 0.1 to 2% by weight. When the content of the hindered phenol compound is less than 0.02% by weight, the thermal stability is poor, the yarn breakage during spinning of the composite fiber is increased, and the process stability is deteriorated. On the other hand, it exceeds 3% by weight. In this case, the yarn breakage during spinning is increased and the process stability is deteriorated. As the hindered phenol compound, specifically, pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,9-bis {2- [3- (3-tert-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane {Sumitomo Chemical ( Same as “Sumilyzer” GA-80. }, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert -Butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3- (3-tert- Butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio- Diethylene-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert Butyl-4-hydroxyphenyl) propionate] and the like. It is also preferable to use these hindered phenol compounds in combination with a thioether-based secondary antioxidant. The method for adding the hindered phenol compound to the polyester is not particularly limited, but preferably includes a method of adding at any stage after the completion of the ester exchange reaction or the esterification reaction until the polymerization reaction is completed. .

  The amount of antimony and germanium metal elements contained in the polyester component A in the present invention needs to be 20 ppm by weight or less. Further, it is more preferably close to 0 ppm by weight. The antimony and germanium metal elements mentioned here are usually used as a polymerization catalyst during polyester production. If the amount of the antimony metal element is large, the amount of deposits around the spinneret increases when forming the composite fiber, making it difficult to produce stable fibers. If the amount of germanium element is large, the cost of the polyester required for fiber production increases. Therefore, it is not preferable. The amount of antimony and germanium metal elements is preferably 15 ppm by weight or less, and more preferably 10 ppm by weight or less.

  In the present invention, the polyester component B is a polyester having ethylene terephthalate as a main repeating unit. Here, “main” means 80 mol% or more of all repeating units. Here, the polyester component B may be a copolymerized polyethylene glycol obtained by copolymerizing a third component other than the component constituting the ethylene terephthalate unit. The third component (copolymerization component) may be either a dicarboxylic acid component or a glycol component. As the component preferably used as the third component, as the dicarboxylic acid component, aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, isophthalic acid and phthalic acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid and the like Aliphatic dicarboxylic acid such as aliphatic dicarboxylic acid, cyclohexanedicarboxylic acid, etc., and glycol components include trimethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, hexamethylene glycol, cyclohexanedimethanol, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane and the like are exemplified, and these can be used alone or in combination of two or more.

  The intrinsic viscosity of the polyester components A and B in the present invention is not particularly limited, but preferably the polyester component A is in the range of 0.3 to 1.0, and the polyester component B is in the range of 0.5 to 0.8. It is preferable that it exists in. In particular, when the intrinsic viscosity of the polyester component B is less than 0.5, the strength of the ultrafine fiber finally obtained is not preferable.

  The polyester component A in the present invention is preferably polymerized using a titanium compound as a polymerization catalyst. The titanium compound here is not an inorganic particle such as titanium oxide, but a titanium compound that is substantially soluble in polyester. More specifically, it is an organic titanium compound, which means a titanium compound that is extracted into a hydrochloric acid layer when hydrochloric acid is extracted after the polyester is dissolved in orthochlorophenol.

  The amount of titanium metal element soluble in the polyester contained in the polyester component A in the present invention is preferably in the range of 5 to 120 ppm by weight. The titanium metal element is a titanium metal element used as the above-described polycondensation catalyst, does not include inorganic particles such as titanium oxide, and is substantially the total amount of the polycondensation catalyst of the polyester component A and the polyester component B. It is. Accordingly, when the element content is less than 5 ppm%, the polymerization activity is insufficient, and when it exceeds 120 ppm, the heat resistance is insufficient. The amount of titanium metal element in the polyester composite fiber is preferably in the range of 7 to 100 ppm by weight, and more preferably in the range of 10 to 70 ppm by weight.

  The titanium compound as a polycondensation catalyst used for polymerizing the polyester component A in the present invention is not particularly limited, and is a general titanium compound as a polyester polycondensation catalyst, such as titanium acetate or tetra-n-butoxy titanium. Etc. Furthermore, in polymerizing the polyester component A, a compound represented by the following general formula (I), a titanium compound represented by the following general formula (I) and an aromatic polyvalent represented by the following general formula (II): A titanium compound component containing at least one selected from the group consisting of a product obtained by reacting a carboxylic acid or an anhydride thereof, and phosphorus represented by the following general formula (III) of 5 to 80 mmol% in terms of phosphorus element An unreacted mixture with the compound can be preferably used as the catalyst system.

［上記式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４はそれぞれ同一若しくは異なって、アルキル基又はフェニル基を示し、ｍは１〜４の整数を表し、かつｍが２、３又は４の場合、２個、３個又は４個のＲ^２及びＲ^３は、それぞれ同一であっても異なっていてもどちらでもよい。］

[Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents an alkyl group or a phenyl group, m represents an integer of 1 to 4, and m is 2, 3, or 4] In this case, 2, 3 or 4 R ² and R ³ may be the same or different from each other. ]

［上記式中、ｎは２〜４の整数を表わす。］

[In the above formula, n represents an integer of 2 to 4. ]

［上記式中、Ｒ^５、Ｒ^６及びＲ^７は、同一又は異なって炭素数原子数１〜４のアルキル基を示し、Ｘは、−ＣＨ_２−又は―ＣＨ（Ｙ）を示す（Ｙは、ベンゼン環を示す）。］

[Wherein R ⁵ , R ⁶ and R ⁷ are the same or different and each represents an alkyl group having 1 to 4 carbon atoms, X represents —CH ₂ — or —CH (Y) (Y represents Represents a benzene ring). ]

  Here, as the titanium compound represented by the general formula (I), specifically, tetraisopropoxy titanium, tetrapropoxy titanium, tetra-n-butoxy titanium, tetraethoxy titanium, tetraphenoxy titanium, octaalkyl trititanate, And hexaalkyl dititanate are preferably used.

  In addition, the aromatic polyvalent carboxylic acid represented by the general formula (II) to be reacted with the titanium compound or the anhydride thereof includes phthalic acid, trimellitic acid, hemimellitic acid, pyromellitic acid and anhydrides thereof. Preferably used.

  When the titanium compound and the aromatic polycarboxylic acid or anhydride thereof are reacted, for example, a part or all of the aromatic polyvalent carboxylic acid or anhydride thereof is dissolved in a solvent, and the titanium compound is dissolved in the mixed solution. Is added at a temperature of 0 to 200 ° C. for at least 30 minutes, preferably 30 to 150 ° C. for 40 to 90 minutes. There is no restriction | limiting in particular about the reaction pressure in this case, A normal pressure is enough.

  As the solvent for dissolving the aromatic polyvalent carboxylic acid or its anhydride, any of ethanol, ethylene glycol, trimethylene glycol, tetramethylene glycol, benzene, xylene and the like can be used as desired.

  Here, the reaction molar ratio of the titanium compound to the aromatic polyvalent carboxylic acid or its anhydride is not particularly limited, but if the ratio of the titanium compound is too high, the color tone of the resulting polyester may deteriorate or the softening point On the contrary, if the proportion of the titanium compound is too low, the polymerization reaction may be difficult to proceed. For this reason, it is preferable that the reaction molar ratio of a titanium compound and aromatic polyvalent carboxylic acid or its anhydride shall be in the range of 2/1-2/5. Also, there is no particular limitation as long as the above titanium compound can be reacted with the aromatic polyvalent carboxylic acid or its anhydride under other conditions.

  The catalyst system used as a polymerization catalyst in the present invention is substantially composed of an unreacted mixture of the above-described titanium compound component and the phosphorus compound represented by the general formula (III). As the phosphorus compound, Carbomethoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carboptoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, carboprotoxy-phosphono-phenylacetic acid and It is preferably selected from dimethyl esters, diethyl esters, dipropyl esters and dibutyl esters of carbobutoxy-phosphono-phenylacetic acid.

  Since the above phosphorus compound reacts relatively slowly with a titanium compound or a titanium compound component (hereinafter abbreviated as “titanium compound etc.”) as compared with a phosphorus compound usually used as a stabilizer, When the catalyst activity duration of the titanium compound or the like during the reaction is long, as a result, the amount of the titanium compound added to the polyester can be reduced, and when a large amount of stabilizer is added to the catalyst as in the present invention Even so, the heat stability of the polyester is hardly impaired.

  The above phosphorus compound is preferably in the range of 5 to 80 mmol% in terms of phosphorus element. If the phosphorus compound is less than 5 mmol%, the hue of the polyester tends to decrease, and if it exceeds 80 mmol%, the polymerization reaction is difficult to proceed. The addition amount of the phosphorus compound is more preferably in the range of 10 to 60 mmol%.

  Although there is no limitation in particular as a polymerization catalyst of the polyester component B of this invention, the antimony compound currently used as a general polyester manufacturing catalyst, especially antimony trioxide are used preferably.

  The production method of the polyester component A and the polyester component B used in the present invention is not particularly limited. A method in which terephthalic acid is directly esterified with a glycol component and then polymerized, and an ester-forming derivative of terephthalic acid is used as a glycol component. Any of a method of polymerizing after the transesterification reaction may be employed.

  However, for the production of the polyester component A, it is preferable to use an ester-forming derivative of an aromatic dicarboxylic acid as a raw material and a production method via a transesterification reaction. As described above, the polyester component A needs to be copolymerized with a compound containing a metal salt of sulfoisophthalic acid, and as a compound containing the metal salt of sulfoisophthalic acid, dimethyl sulfometal salt of sulfoisophthalic acid superior in transesterification reaction can be used. Esters can be obtained at a relatively low cost, which is advantageous in terms of cost.

  Further, in the production method using dimethyl terephthalate as a raw material as an ester-forming derivative of terephthalic acid, a part and / or whole amount of a titanium compound can be added before the transesterification reaction can be reduced, A production method in which two catalysts of a transesterification catalyst and a polycondensation reaction catalyst are used in combination is preferable. In addition, this transesterification reaction may be implemented by a normal-pressure reaction, or may be implemented under the pressurization of 0.05-0.20 MPa.

  In the production method using dimethyl terephthalate as a raw material described above, a polyester is obtained by performing a polycondensation reaction via a transesterification reaction. As the transesterification catalyst used here, a calcium compound and / or a magnesium compound can also be used. The calcium compound and the magnesium compound here need to be compounds active as a transesterification reaction catalyst. Specifically, as the calcium compound, calcium acetate, calcium sulfate, calcium carbonate, calcium chloride, calcium benzoate Calcium formate, calcium stearate and hydrates thereof, and magnesium compounds include magnesium acetate, magnesium sulfate, magnesium carbonate, magnesium chloride, magnesium benzoate, magnesium formate, magnesium stearate and hydrates thereof, respectively. These may be mentioned, and these may be used alone or in combination of two or more. Of these, calcium acetate monohydrate and magnesium acetate tetrahydrate are particularly preferably used.

  In the polyester component A and the polyester component B used in the present invention, a small amount of additives as necessary, for example, lubricants, pigments, dyes, antioxidants, solid phase polymerization accelerators, fluorescent whitening agents, antistatic agents, An antibacterial agent, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a light-shielding agent, a matting agent, and the like may be included. Particularly, in the polyester component B, titanium oxide or the like is preferably added as a matting agent.

  In order to produce the split polyester composite fiber of the present invention described above, any known spinning conditions can be employed without any trouble using a conventionally known composite spinneret and composite spinning apparatus. For example, a method in which melt spinning is performed at a speed of 500 to 2500 m / min, stretching and heat treatment, a method in which melt spinning is performed at a speed of 1500 to 5000 m / min, and stretching and false twisting are performed simultaneously or subsequently 5000 m / min or more Arbitrary spinning conditions can be employed in methods such as melt spinning at high speed and omitting the stretching step depending on the application. In addition, the obtained fiber or a woven or knitted fabric produced from the fiber may be heat-treated at a temperature of 100 ° C. or higher to improve the structural stability, and if necessary, relaxation heat treatment may be used in combination. .

  The composite shape of the specific polyester component A and the polyester component B and the fiber cross-sectional shape of each component are arbitrary as long as the polyester component B shows a shape divided into a plurality of portions by the polyester component A, Some examples are shown in FIGS.

  In FIG. 1, A is a copolyester composition (polyester component A), and B is polyester (polyester component B). (A)-(c) in the figure is the schematic diagram which showed the cross-sectional shape of the split type composite fiber in which the polyester component B is divided | segmented into 16 by the polyester component A. FIG. Further, (d) in the figure is a schematic diagram showing a cross-sectional shape of a sea-island type split conjugate fiber in which the polyester component A is the sea and the polyester component B is the island. It is divided into Further, (e) and (f) in the figure are schematic views showing the cross-sectional shape of the split-type composite fiber having a flat cross-sectional shape, and finally (g) to (i) in the figure are respectively (a). The outer peripheral part is further covered with the polyester component A with respect to the fibers of (c).

  The polyester composite fiber of the present invention preferably has a fiber cross-sectional shape in which the polyester component B is completely covered with the polyester component A.

  As described above, in the present invention, the amount of the antimony element in the polyester component A is reduced, so that a stable fiber can be produced. However, when a polyester using an antimony compound as a polymerization catalyst is used as the polyester component B, the antimony compound resulting from the polyester component B becomes a deposit on the periphery of the spinneret, which may make it difficult to produce stable fibers. . However, when the polyester component B is completely covered with the polyester component A, it is possible to suppress the adhesion of the antimony compound due to the polyester component B around the spinneret.

  In order to produce a composite fiber in which the polyester component B is completely covered with the polyester component A, (d), (g) in the schematic diagram showing the cross-sectional shape of the split polyester composite fiber described above. , (H) and (i) are preferably used.

  The split-type polyester conjugate fiber can be made into a very fine polyester fiber by removing only the polyester component A by alkali treatment and / or hot water treatment after forming into a fabric. At the same time, since a space can be provided between the fibers, it is suitable for obtaining a fabric having a bulky and soft texture. In order to perform the alkali treatment here, for example, a method in which an aqueous solution of sodium hydroxide having a concentration of 10 to 100 g / L is maintained at 60 ° C. or higher and the fabric is immersed in this solution is usually performed. In order to perform the hot water treatment, for example, a method of immersing the fabric in water having a temperature of 90 ° C. or higher is performed. The treatment time is an appropriate time for removing the polyester component A, and is usually 0.5 to 30 hours, and can be easily grasped by those skilled in the art. These treatments can be performed either batchwise or continuously. After completion of these treatments, washing / drying treatment and the like can be performed to obtain a fabric containing ultrafine fibers as described above. In the ultra fine polyester fiber of the present invention, one structural unit (single yarn) composed only of the polyester component B is 0.001 to 0.3 dtex or less, and the number of the structural units is 16 or more, particularly 24 or more. The effect obtained (presenting a bulky and soft texture) becomes remarkable and preferable.

  The composite ratio of the polyester component A and the polyester component B in the split polyester composite fiber is (polyester component A: polyester component B) from the viewpoint of achieving both easy splitting by alkali treatment and fiber physical properties of the composite fiber. The weight ratio is preferably in the range of (80:20) to (2:98), and more preferably in the range of (60:40) to (5:95).

Hereinafter, the present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. In addition, each value in an Example was calculated | required according to the following method.
(1) Intrinsic viscosity:
The intrinsic viscosity of the polyester polymer was determined from the viscosity value measured at 35 ° C. according to a conventional method using an orthochlorophenol solution.
(2) Diethylene glycol amount:
The sample was decomposed using hydrazine hydrate (hydrazine hydrate), and the amount of diethylene glycol was determined using gas chromatography (HP6890 Series GC System, manufactured by HEWLETT PACKARD). From the quantitative value, the copolymerization amount of the diethylene glycol unit based on the measured weight of the polymer was obtained as a percentage by weight.
(3) Polymer tone (color L value and color b value):
The polymer chip was measured by using a colorimetric color difference meter Z-1001DP manufactured by Nippon Denshoku Industries Co., Ltd. after a dry crystallization treatment at 130 ° C. for 1 hour. The L value indicates the lightness, and the larger the value, the higher the lightness. The b value indicates the greater the yellowness, the greater the value. Other detailed measurement methods were performed in accordance with JIS Z-8729.
(4) Titanium, antimony and germanium content of polyester component A in the composite fiber:
Only the polyester component A was removed from the composite fiber sample using a 35 g / L sodium hydroxide aqueous solution at 90 ° C. The sodium hydroxide aqueous solution containing the removed polyester component A was quantified using a Z-8100 type atomic absorption photometer manufactured by Hitachi, Ltd.

(5) Deposited layer generated in the spinneret:
Spinning was carried out for 2 days, and the height of the layer of deposits generated at the outer edge of the outlet of the die was measured. As the height of the adhered layer increases, bending is more likely to occur in the filament flow of the discharged polyester melt, and the moldability of the polyester becomes lower. That is, the height of the deposit layer generated in the spinneret is an index of the moldability of the polyester.
(6) Composite fiber cross-sectional shape:
The drawn composite fiber was cut with a razor, and the cross-sectional shape of the fiber was observed using a scanning electron microscope S-3500 manufactured by Hitachi, Ltd. A case where the polyester component B was completely covered with the polyester component A was marked with ◯, and a case where the polyester component B was not covered with x.
(7) Method for measuring content of compound containing phosphoroisophthalic acid metal base and phosphorus element amount:
After the obtained copolymerized polyester composition was heated and melted on an aluminum plate, a test molded body having a flat surface was prepared with a compression press machine, and a fluorescent X-ray apparatus (type 3270E manufactured by Rigaku Corporation) was used. The content of sulfur element and phosphorus element was measured, and the content mol% relative to the total acid component was determined.
(8) Content of polyoxyalkylene glycol and hindered phenol compound:
A polymer 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 to determine a nuclear magnetic resonance spectrum ( ¹ H- NMR) was measured, and the content of the polyoxyalkylene glycol component and the content of the hindered phenol compound were determined from the spectrum pattern according to a conventional method.

[Reference Example 1]
Adjustment of titanium trimellitic acid (TMT):
One half moles of tetrabutoxytitanium with respect to trimellitic anhydride was added to an ethylene glycol solution of trimellitic anhydride (0.2%), and the reaction was carried out for 60 minutes while maintaining at 80 ° C. under atmospheric pressure. Thereafter, the reaction mixture was cooled to room temperature, the produced catalyst was recrystallized with 10 times the amount of acetone, the precipitate was filtered through filter paper, and dried at 100 ° C. for 2 hours to obtain the desired catalyst.

[Reference Example 2]
Production of polymer for polyester component A:
In a mixture of 97.5 parts of dimethyl terephthalate, 3.8 parts of dimethyl 5-sodium sulfoisophthalate, and 65 parts of ethylene glycol, 0.017 parts of tetra-n-butyl titanate and 0.109 parts of sodium acetate were stirred. Charge to a reactor equipped with a rectifying column and a methanol distillation condenser, and gradually raise the temperature from 140 ° C, while distilling methanol generated as a result of the reaction out of the system, raise the temperature to 240 ° C and transesterify Reaction was performed.

  Next, 11 parts of polyethylene glycol having a number average molecular weight of 4000 and 0.30 part of a hindered phenol compound (manufactured by Sumitomo Chemical Co., Ltd., “Sumizer GA-80”) are added to the obtained reaction product, and a stirrer and glycol are added. The reactor was transferred to another reactor equipped with a distillation condenser, and the polymerization reaction was carried out while gradually raising the temperature from 240 ° C. to 285 ° C. and reducing the pressure to a high vacuum of 70 Pa or less. While tracing the melt viscosity of the reaction system, the polymerization reaction was terminated when the intrinsic viscosity reached 0.70.

  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. As a result of analyzing the obtained copolyester, the hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Reference Example 3]
Production of polymer for polyester component A:
In Reference Example 2, the same operation was performed except that the titanium compound was changed to 0.032 part of trimellitic acid titanium prepared by the method of Reference Example 1 above. The hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Reference Example 4]
Production of polymer for polyester component A:
In Reference Example 2, the same operation was performed except that 0.023 part of triethylphosphonoacetate was added at the end of the transesterification reaction to terminate the transesterification reaction. The hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Reference Example 5]
Production of polymer for polyester component A:
The same operation as in Reference Example 2 was performed except that the types and amounts of dimethyl 5-sodium sulfoisophthalate, polyethylene glycol, triethylphosphonoacetate, and titanium catalyst were changed to the amounts shown in Table 1. The hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Reference Example 6]
To a mixture of 97.5 parts of dimethyl terephthalate, 3.8 parts of dimethyl 5-sodium sulfoisophthalate, and 65 parts of ethylene glycol, 0.063 parts of calcium acetate monohydrate and 0.109 parts of sodium acetate were stirred. Charge to a reactor equipped with a rectifying column and a methanol distillation condenser, and gradually raise the temperature from 140 ° C, while distilling methanol generated as a result of the reaction out of the system, raise the temperature to 240 ° C and transesterify Reaction was performed.

  After adding 0.05 part of phosphoric acid aqueous solution with a concentration of 56% by weight to the obtained reaction product to complete the transesterification reaction, 0.032 part of titanium trimellitic acid prepared in Reference Example 1, number average molecular weight Add 11 parts of 4000 polyethylene glycol and 0.30 part of a hindered phenol compound (Sumitomo Chemical Co., Ltd., “Sumizer” GA-80) and transfer to another reactor equipped with a stirrer and glycol distillation condenser. The polymerization reaction was carried out while gradually raising the temperature from 240 ° C. to 285 ° C. and reducing the pressure to a high vacuum of 70 Pa or less. While tracing the melt viscosity of the reaction system, the polymerization reaction was terminated when the intrinsic viscosity reached 0.70. A chip was formed in the same manner as in Reference Example 2. As a result of analyzing the obtained copolyester, the hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Comparative Reference Example 1]
Production of polymer for polyester component A:
In a mixture of 97.5 parts of dimethyl terephthalate, 3.8 parts of dimethyl 5-sodium sulfoisophthalate, and 65 parts of ethylene glycol, 0.032 parts of manganese acetate tetrahydrate and 0.109 parts of sodium acetate were added to a stirrer. Charge to a reactor equipped with a rectifying column and a methanol distillation condenser, and gradually raise the temperature from 140 ° C, while distilling methanol generated as a result of the reaction out of the system, raise the temperature to 240 ° C and transesterify Reaction was performed. Next, 0.020 part by weight of trimethyl phosphate was added to complete the transesterification reaction, and then the resulting reaction product was added to 11 parts of polyethylene glycol having a number average molecular weight of 4000, a hindered phenol compound (manufactured by Sumitomo Chemical Co., Ltd.). , “Sumilyzer” GA-80), 0.30 part, 0.045 part of antimony trioxide are added, transferred to another reactor equipped with a stirrer and a glycol distillation condenser and gradually increased from 240 ° C. to 285 ° C. While raising the temperature, the polymerization reaction was carried out while reducing the pressure to a high vacuum of 70 Pa or less. While tracing the melt viscosity of the reaction system, the polymerization reaction was terminated when the intrinsic viscosity reached 0.70.

  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. As a result of analyzing the obtained copolyester, the hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Comparative Reference Example 2]
Production of polymer for polyester component A:
The same operation as in Comparative Example 1 was performed except that the amounts of dimethyl 5-sodium sulfoisophthalate and polyethylene glycol were changed to those shown in Table 1. As a result of analyzing the obtained copolyester, the hindered phenol compound contained 0.3% by weight. Other results are shown in Table 1.

[Reference Example 7]
Production of polymer for polyester component B:
A mixture of 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol was charged with 0.032 parts by weight of manganese acetate tetrahydrate in a reactor equipped with a stirrer, a rectifying column and a methanol distillation condenser, and 140 ° C. The ester exchange reaction was carried out while distilling out the methanol produced as a result of the reaction while gradually raising the temperature to 240 ° C. Thereafter, 0.020 part by weight of trimethyl phosphate was added to complete the transesterification reaction.

  Subsequently, 0.040 parts of diantimony trioxide and 1.5 parts of ethylene glycol slurry of 20% by weight of titanium oxide were added to the obtained reaction product, and then a stirrer, a nitrogen inlet, a vacuum port, and a distillation device were provided. The mixture was transferred to a reaction vessel, and the temperature was gradually raised from 240 ° C. to 285 ° C., and the polymerization reaction was carried out while reducing the pressure to a high vacuum of 70 Pa or less. The polymerization reaction was terminated when the intrinsic viscosity reached 0.63 while tracing the melt viscosity of the reaction system. 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 results are shown in Table 1.

[Examples 1-5, Comparative Examples 1-2]
As polyester component A and polymer component B, as shown in Table 2, using the polymers obtained in Reference Examples 1-7 and Comparative Reference Examples 1-2, using a die of the type shown in FIG. The island component and the sea component were simultaneously spun from the composite spinneret at a composite ratio of the polyester component A and the polyester component B of 50/50 (weight ratio) to obtain a sea-island type composite undrawn yarn. The spinning temperature at that time was 290 ° C. and the spinning speed was 3000 m / min. A single yarn fineness was 0.08 dtex), and an undrawn yarn having a sea component of 50% was obtained. This composite undrawn yarn was drawn under the conditions of a heating plate temperature of 200 ° C. and a draw ratio of 1.15 times to obtain a drawn yarn. Next, the obtained composite fiber was made into a plain woven fabric and subjected to a 50% by weight alkali reduction treatment in a sodium hydroxide aqueous solution (concentration 35 g / liter) at a temperature of 90 ° C. to obtain a woven fabric of ultrafine fibers. The results are shown in Table 2.

[Example 6]
A woven fabric of composite fibers and ultrafine fibers was obtained in the same manner as in Example 1 except that the shape of the die was changed to that of the mold shown in FIG. The results are shown in Table 2.

  As is clear from Table 2, those within the scope of the present invention showed good moldability with a small amount of base deposit, but when outside the scope of the present invention (Comparative Examples 1-2), The amount of the die attached was very large and the moldability was poor. Further, those satisfying up to claim 2 of the present invention (Examples 1 to 5) had a very small amount of base deposits.

  According to the present invention, it is possible to provide a split-type polyester composite fiber having the performance that even if it is continuously spun through a spinneret for a long time, the amount of the deposit on the die is very small and the moldability is excellent. . Moreover, an ultra fine fiber can be easily provided by performing alkali weight loss etc. to a composite fiber. When a woven or knitted fabric is prepared using the composite fiber and then subjected to alkali weight reduction or the like, a space can be provided between the fibers. As a result, the woven or knitted fabric is suitable for obtaining a fabric having a bulky and soft texture.

  Further, in the present invention, since the content of antimony element in the polyester component A, which is susceptible to alkali weight loss, is low, it is possible to reduce the antimony metal element contained in the alkali weight loss waste water. As a result, since the manufacturing process is an environmentally friendly process, the industrial significance is extremely great.

It is an example of the expanded cross-sectional shape figure of the split-type polyester composite fiber of this invention.

Explanation of symbols

A component A
B component B

Claims (11)

A composite fiber comprising a polyester component A and a polyester component B, wherein the polyester component B has a fiber cross-sectional shape divided into a plurality by the polyester component A,
(1) From the product in which the polyester component A is reacted with a titanium compound represented by the following general formula (I) and an aromatic polyvalent carboxylic acid represented by the following general formula (II) or an anhydride thereof A catalyst system consisting essentially of an unreacted mixture of a titanium compound component containing at least one selected from the group consisting of 5 to 80 mmol% of a phosphorus compound represented by the following general formula (III) in terms of phosphorus element Polymerized,

[Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents an alkyl group or a phenyl group, m represents an integer of 1 to 4, and m is 2, 3, or 4] In this case, 2, 3 or 4 R ² and R ³ may be the same or different from each other. ]

[In the above formula, n represents an integer of 2 to 4. ]

[In the above formula, R ⁵ , R ⁶ and R ⁷ are the same or different and each represents an alkyl group having 1 to 4 carbon atoms, and X represents —CH ₂ — or —CH (Y) (Y represents Represents a benzene ring). ]
Further, as polyester component A , a copolymerized polyester obtained by copolymerizing 1 to 8 mol% of a compound containing a metal salt of sulfoisophthalic acid based on the total acid components (including compounds containing a metal salt of sulfoisophthalic acid) constituting the polyester. Further, based on the polyester component A, the polyoxyalkylene glycol having a number average molecular weight of 400 to 30000 is 1 to 20% by weight, the hindered phenol compound is 0.02 to 3% by weight, and the amounts of antimony and germanium metal elements are Containing a copolymerized polyester composition containing 20 ppm by weight or less and having a diethylene glycol unit copolymerized in an amount of 0.5 to 5.0% by weight based on the polyester component A;
(2) A polyester having an ethylene terephthalate unit as a main repeating unit is arranged as the polyester component B.
Split polyester composite fiber.   The composite fiber according to claim 1, wherein the polyester component B has a fiber cross-sectional shape completely covered with the polyester component A.   The composite fiber according to claim 1, wherein the polyester component A is a polyester polymerized using a titanium compound as a polymerization catalyst.   The composite fiber according to claim 1, wherein the polyester component B is a polyester polymerized using an antimony compound as a polymerization catalyst.   The composite fiber according to claim 3, wherein, among the titanium compounds contained in the composite fiber, the amount of titanium metal element soluble in polyester is 5 to 120 ppm by weight.   The composite fiber according to claim 1, wherein the polyester component A is obtained by performing a polycondensation reaction via a transesterification reaction, and a catalyst used in the transesterification reaction is a calcium compound and / or a magnesium compound. The composite fiber according to any one of claims 1 to 6, wherein a composite ratio of the polyester component A and the polyester component B is 80:20 to 2:98. The composite fiber according to any one of claims 1 to 7, wherein the intrinsic viscosity of the polyester component A is 0.3 to 1.0. The composite fiber according to any one of claims 1 to 8, wherein the intrinsic viscosity of the polyester component B is 0.5 to 0.8. Lupo Riesuteru fibers obtained by removing with claim alkaline aqueous solution only polyester component A in the composite fibers of any one of claims from 1 to 9 and / or hot water. The polyester fiber according to claim 10, wherein the fineness of the single yarn comprising the polyester component B is 0.001 to 0.3 dtex.

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