JP2010084257A - Cross sectional form-controlled fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyethylene terephthalate fiber having a controlled cross sectional form of a fiber for weight reduction a fiber having a modified cross section, or an extremely fine fiber, or the like, and to provide a method for producing the same. <P>SOLUTION: The method for producing the cross sectional form-controlled fiber uses A-components 1, 3, 5, 7, and 9 as the polyethylene terephthalate and B-components 2, 4, 6, 8, and 10 as a block copolymer having a prescribed constituting ratio of polystyrene blocks to polyolefin blocks, having a melt flow rate of the component B of not less than 3 g/10 min, having a prescribed constitution rate of the component A to the component B and extruding the molten polymers of the component A and component B from a composite spinning nozzle and spinning the molten polymers at a high speed of not less than 5 km/min. The composite fiber obtained by the this method, and the polyethylene terephthalate fiber obtained by removing the component B from the composite fiber are also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fiber having a controlled cross-sectional shape and a method for producing the same, and more particularly to a polyethylene terephthalate fiber having a controlled cross-sectional shape such as a weight-reducing fiber, a modified cross-sectional fiber, and an ultrafine fiber, and a method for producing the same.

  Fiber cross-sectional shape control processing includes weight reduction processing using an alkaline solution or the like, irregular cross-section fiber formation by composite spinning, ultrafine fiber formation, and the like. In woven fabrics made of polyethylene terephthalate fibers, the surface of the fibers is dissolved with an alkali-concentrated solution to eliminate the intuition of the fibers, and the fiber diameter is reduced by this weight reduction process, thereby improving the draping properties of the fabric. For this purpose, alkali weight loss processing is often used. However, in addition to the essential problem of dissolving an originally effective component, there is a problem that much labor and time are required for immersion, dissolution, alkali removal, drying, etc. in an alkali (sodium hydroxide) concentrated solution. In order to alleviate these problems, a method using a composite fiber of polyethylene terephthalate and a water-soluble polymer has been tried (Japanese Patent Laid-Open Nos. 7-268770 and 10-204729). However, water-soluble polymers have poor thermal stability, and the molecular weight decreases when complex spinning is performed, making it difficult to recover and reuse them for the same purpose. Polyethylene terephthalate is not only capable of high-speed spinning, but also has a high production speed, and is characterized by good physical properties and good productivity because the drawing process can be omitted. In composite spinning with a polymer, it becomes difficult to spin at a higher speed than in the case of single spinning of polyethylene terephthalate fiber due to yarn breakage or the like, and the good productivity of polyethylene terephthalate fiber is not utilized.

  By making the fibers extremely fine (several micrometers), not only the texture is improved, but also new developments such as artificial leather are shown. In the case of polyethylene terephthalate fibers, ultrafine fibers are also manufactured by sea-island fiber spinning using polystyrene as a sea component and polyethylene terephthalate as an island component (for example, Japanese Patent Publication No. 60-35451). Polystyrene has good thermal stability and good solubility in organic solvents, so polystyrene can be recycled and reused, but in the case of composite spinning of polystyrene and polyethylene terephthalate, spinning at a high speed of 5 km / min or more is required. However, due to the influence of the polystyrene component, the degree of orientation of the polyethylene terephthalate component is not sufficiently high, and the good productivity of the polyethylene terephthalate fiber is still not utilized (for example, 1995 Journal of Textile Science, Vol. 51, No. 9). , P.408). For example, Japanese Patent Application Laid-Open No. 11-158726 describes an invention for obtaining a filament of high strength and high elongation from a composite fiber of polyethylene terephthalate and a styrene polymer, but the spinning speed is as low as 3 km / min or less. It is a requirement to spin with. Similarly, when obtaining a modified cross-sectional shape fiber by composite spinning of polyethylene terephthalate and other polymers, the other polymers can be recycled and reused, and the high productivity of polyethylene terephthalate fibers by high-speed spinning is utilized. It has not been realized to make it compatible.

  In addition, even if the component spun with polyethylene terephthalate is compatible with high-speed spinning, fibers taken up at room temperature may stick together, so that the resulting composite fiber has good single fiber separation. Is also a necessary condition. Furthermore, it is also strongly demanded from an environmental viewpoint that an organic solvent used as a solvent for removing one component in composite spinning can be recycled and reused and is not harmful to human bodies.

JP-A-7-268770 (page 1-2) JP-A-10-204729 (page 1-2) Japanese Patent Publication No. 60-35451 (page 1-2) JP-A-11-158726 (page 1-2) Yuji Shibuya and three others, Journal of the Textile Society of Japan (1995) Vol. 51, no. 9, p408-415

  An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide means for variously controlling the fiber cross-sectional shape without impairing the high-speed spinnability of the polyethylene terephthalate fiber. is there. Further, the present invention controls the fiber cross-sectional form by dissolving and removing components other than polyethylene terephthalate with a solvent in a composite fiber obtained by composite spinning of polyethylene terephthalate and another polymer. However, not only does high-speed spinnability not be disturbed, but also high-speed spinning eliminates the sticking between the wound fibers caused by the polymer, which is another component, and improves single fiber separation. With the goal. Another object of the present invention is to recover and reuse the removed polymer component. Another object of the present invention is to make it possible for the solvent for dissolving and removing the polymer component with a solvent to be a solvent that is less harmful to the human body, and to recover and reuse the solvent. .

  The present invention has been made to achieve the above object, wherein the component A is polyethylene terephthalate, the component B is a block copolymer composed of a polystyrene block and a polyolefin block, and the component B is 100%. When the former block is 5% or more and 60% or less, and the latter block is 95% or less and 40% or more, the melt flow rate of the B component is 3 g / 10 min or more, and by weight percent, the A component is 50%. With the composition ratio of 95% or less and the B component being 5% or more and 50% or less, the molten polymer of the A and B components is extruded from the composite spinning nozzle, and is spun at a spinning speed of 5 km / min or more. The present invention relates to a method for producing a cross-sectional shape control fiber. The present invention also relates to a method for producing the cross-sectional shape control fiber, wherein the polyolefin component of the B component is an ethylene / propylene copolymer. The present invention also relates to a method for producing the cross-sectional shape control fiber, wherein the composite spinning nozzle is a core-sheath type composite spinning nozzle having a B component as a sheath and an A component as a core. The composite spinning nozzle is a composite spinning nozzle in which an A component and a B component are arranged side by side. The present invention also relates to a method for producing a cross-sectional shape control fiber that is a sea-island fiber spinning nozzle or a split fiber spinning nozzle in which the composite spinning nozzle uses an A component as an ultrafine fiber component. Moreover, this invention relates to the said cross-sectional form control fiber obtained by the composite spinning which consists of said A component and said B component. Furthermore, the present invention comprises a filament mainly composed of the component A obtained by removing the component B with a solvent containing limonene as a main component, the birefringence of the filament is 0.09 or more, and the boiling water shrinkage is 6%. The following relates to the cross-sectional shape control fiber.

  The present invention makes it possible to control various cross-sectional forms by dissolving and removing the B component with a solvent in the fiber obtained by the composite spinning of polyethylene terephthalate (A component) and another polymer (B component). It is. Polyethylene terephthalate, which is the component A used in the present invention, is a spinning resin used for normal high-speed spinning, and its intrinsic viscosity is preferably 0.5 or more and 1.2 or less, and 0.6 or more and 1 .1 or less is more preferable. Further, a small amount of titanium oxide, an ultraviolet deterioration preventing agent and the like can be blended and used.

  The B component in the composite spinning of the present invention should not interfere with the high speed spinning characteristics of the polyethylene terephthalate fiber. Polystyrene used in the production of ultrafine fibers and the like is often used as the B component of composite spinning because of its good solvent solubility and good spinnability. However, it has already been mentioned that polystyrene does not increase the degree of orientation of the polyethylene terephthalate component even when spinning at a speed of 5 km / min or more. The reason is that, since the solidification temperature of polystyrene is higher than the solidification temperature of polyethylene terephthalate, when compounding, the polystyrene component side solidifies first and stress concentrates, while the polyethylene terephthalate (A component) side solidifies. It is considered that one of the causes is that the orientation is relaxed. As a result of intensive studies on the B component that does not hinder the high-speed spinnability of the polyethylene terephthalate, the present invention has reached a copolymer in which a block composed of a polystyrene component and a block copolymer composed of a polyolefin component have a special composition ratio. In addition, by using these copolymers, the solidification temperature of the polymer is lowered, but by doing so, the other polyethylene terephthalate (component A) side is solidified first, and the spinning stress is concentrated. It has been found that fibers with sufficiently high degree of orientation and strength can be obtained at a winding speed lower than the high speed spinning speed of typical polyethylene terephthalate. On the other hand, with the decrease in the solidification temperature of the component B, there is a concern that the wound fibers are stuck and the single fiber separation property is deteriorated. However, in the present invention, the strength of the fiber itself is sufficiently increased by high-speed spinning. It was also found that the single fiber separability can be improved by increasing it.

  The block copolymer which is the B component constituting the composite fiber of the present invention is a block copolymer composed of a block composed of a polystyrene component in advance and a polymer block obtained by homopolymerizing or copolymerizing a conjugated diene compound, and comprising a styrene component. By hydrogenating unsaturated bonds existing other than the block, a block composed of an olefin component was formed. As a result, the heat deterioration resistance was improved, and a polymer having a high speed spinnability could be obtained.

  The B component of the present invention is a block copolymer composed of a polystyrene block and a polyolefin block. When the B component is 100%, the former block is 5% (hereinafter simply referred to as% because it is all by weight) and 60% or less, and the latter block is 95% or less and 40%. More preferably, the polystyrene component is 10% or more and 40% or less of the block, and the polyolefin component is 90% or less and 60% or more. In addition, the block copolymer as the B component is preferably such that the ends of the block composed of the polystyrene component and the block composed of the polyolefin component are bonded to each other, and each block is connected linearly as a whole. More preferably, one block composed of a styrene component is bonded to each end. By making these polymer components and constituent ratios, a. Satisfied high-speed spinnability; b. Good single fiber separation, c. Soluble in solvents based on limonene derived from plants that are less harmful to the human body, d. The filament composed of the A component from which the B component has been removed has a high degree of molecular orientation, has a low boiling water shrinkage, and becomes a fiber that can be put to practical use as it is, e. In addition, since these B component and solvent can be recovered and reused for the same purpose, it is environmentally friendly and inexpensive.

  The block consisting of the polyolefin component of the B component plays an important role for lowering the solidification temperature, and is a polyolefin represented by polyethylene and polypropylene having a lower solidification temperature than the polyethylene terephthalate of the A component. Preferably, an ethylene / propylene copolymer is more preferable, and an ethylene / propylene alternating copolymer is most preferable. A block composed of an alternating ethylene / propylene copolymer can be formed by using isoprene as the conjugated diene compound used for producing the block copolymer as the B component, and hydrogenating after polymerization. This is because this copolymer can further exhibit the characteristics shown in the ae. The block copolymer (component B) having an ethylene / propylene copolymer component can greatly improve the thermal stability in melt spinning, and can further improve the recyclability of the block copolymer.

  In the composite spinning in the present invention, in order to satisfy the high-speed spinning property, the B component melt flow rate is 3 g / 10 min or more, more preferably 5 g / 10 min or more and 150 g / 10 min or less. A high melt flow rate means that the molecular weight of the component B is low, and that only a certain molecular weight range satisfies high-speed spinnability. The melt flow rate in the present invention was measured at 230 ° C. and 2.16 kgf in accordance with JIS K7210. In the examples, values measured at 200 ° C. and a load of 10 kgf were also referred to.

  The A component and the B component in the present invention can satisfy all of the ae at the same time only in the case of a specific ratio. The component ratio is such that the A component is 50% or more and 95% or less, the B component is 5% or more and 50% or less, and more preferably, the A component is 58% or more and 92% or less. Is 8% or more and 42% or less, and most preferably, the A component is 65% or more and 90% or less, and the B component is 10% or more and 35% or less.

    The composite fiber of the present invention has a release agent, heat stabilizer, antioxidant, ultraviolet absorber, flame retardant, antibacterial agent, deodorant, fragrance, fluorescent whitening agent, matting agent, and coloring as necessary. You may mix | blend additives, such as an agent, an antistatic agent, and inorganic fine particles.

  The present invention is characterized in that the melt composed of the A component and the B component is subjected to composite spinning by being extruded by a composite spinning nozzle. The composite spinning nozzle can be made into a core-sheath type composite fiber by using a core-sheath type composite spinning nozzle having a B component as a sheath and an A component as a core. Moreover, it can be set as a side-by-side type | mold composite fiber because a composite spinning nozzle is a composite spinning nozzle which mix | blends A component and B component side by side. In the composite fibers obtained by these composite spinning nozzles, the B component on the surface can be easily dissolved and removed with a solvent, so that polyethylene terephthalate fibers for weight reduction processing can be obtained. Moreover, in these composite spinning nozzles, the fiber cross-sectional shape of the A component can be controlled in advance, so that polyethylene terephthalate fibers having various irregular cross sections can be obtained by dissolving and removing the B component. The irregular cross-section fiber can change the gloss, texture, bending strength, etc. of the fiber, and has been put to practical use in various applications. Furthermore, since the composite spinning nozzle is a sea-island fiber spinning nozzle or a split fiber spinning nozzle in which the A component is an ultrafine fiber component, the B component can be dissolved and removed to form polyethylene terephthalate ultrafine fibers.

The present invention is characterized by enabling high-speed spinning in composite spinning. High speed spinning with polyester alone is usually performed at 6 km / min. If it is less than 6 km / min, high molecular orientation cannot be obtained due to insufficient spinning stress. If it exceeds 6 km / min, an expensive winding device is required and the skin-core type non-uniformity in the fiber cross section This is because a structure is easily formed and the polyester fiber is not suitable for general use. High-speed spinning is not only good in productivity due to the high spinning speed, but also has good physical properties such as good molecular orientation and low boiling water shrinkage, resulting in productivity and cost advantages. Is big. On the other hand, the high speed spinning of the present invention is preferably performed at 5 km / min or more and 7 km / min or less. In the present invention, since a block copolymer component having a solidification temperature relatively lower than that of the polyester component is used in the composite spinning, the polyester component is solidified first, stress is concentrated, and the speed is lower than that of general high-speed spinning. The same fiber structure is formed. Incidentally, if the polyester component is controlled so as not to be exposed to the fiber surface by the composite spinning nozzle, a non-uniform structure hardly occurs even at a speed exceeding 7 km / min, and the filament has good yarn quality. As described above, the high-speed spinning in the present invention is an essential requirement not only for productivity and cost, but also for improving the single fiber separation of the component B in composite spinning by high-speed spinning.

  In the present invention, the fiber cross-sectional form is controlled by removing the B component from the composite fiber with a solvent. In the conventional weight loss processing of polyethylene terephthalate fiber, a sodium hydroxide solution was used and a long time (around 60 minutes) was required at a high temperature (around 100 ° C.). It can be processed in a short time (around 15 minutes). As the solvent, organic solvents such as trichloroethylene and toluene can be used, but these are harmful to human bodies and cause environmental pollution. Therefore, the present invention is characterized in that the B component is removed with a solvent mainly composed of plant-derived limonene, and a solvent having little influence on the human body and the environment is used. The solvent containing limonene as a main component is preferably a liquid containing 90 wt% or more of d-limonene, and an additive such as ethanol may be blended for the purpose of increasing the dissolution rate of the B component. Good.

  The B component of the high-speed spun composite fiber of the present invention is removed from the solvent, and a polyethylene terephthalate fiber having a controlled fiber cross-sectional shape is obtained. The cross-sectional form of the polyethylene terephthalate fiber will be described in detail with reference to the drawings. Further, the polyethylene terephthalate fiber has the characteristics that the molecular orientation is good and the boiling water shrinkage is small. Evaluation of molecular orientation is usually performed by measuring birefringence. The polyethylene terephthalate fiber obtained by the present invention has a birefringence of 0.09 or more and preferably 0.10 or more. Polyethylene terephthalate fibers whose molecular orientation is enhanced by high-speed spinning have high crystallinity as well as birefringence, so that they have sufficient strength and high heat resistance and can be used in a wide range of applications including clothing. Furthermore, the polyethylene terephthalate fiber of the present invention is characterized by having a boiling water shrinkage of 6% or less, preferably 4% or less, and also has practical characteristics. A small boiling water shrinkage means that the produced woven fabric, knitted fabric, nonwoven fabric, etc. exhibits excellent dimensional stability, which is advantageous when post-processing such as dyeing or heat setting, and remains spun. It can be used for the production process without any special treatment.

The present invention can provide a composite fiber in which the fiber cross-sectional shape can be controlled in various ways without impairing the high-speed spinnability of the polyethylene terephthalate fiber in the composite spinning of polyethylene terephthalate and a block copolymer having a special configuration. it can. The present invention also provides
In the composite fiber obtained by the composite spinning of polyethylene terephthalate and other polymer (B component), the fiber cross-sectional form is controlled by dissolving and removing the B component with a solvent. In addition to not hindering the properties, the high-speed spinning was able to eliminate the sticking between the wound fibers caused by the polymer as another component, and to improve the single fiber separation. Further, the present invention can remove the B component by solvent treatment at a low temperature for a short time, and the removed polymer component is recovered and reused for the same application. Further, the solvent for dissolving and removing the polymer component with the solvent is a human body. Limonene, a solvent that is less harmful to water, can also be recovered and reused. That is, in the conventional alkali weight reduction processing, harmful components come out from the effluent, but in the present invention, all of these effluent components can be recovered and reused, and zero emission treatment, which is a waste liquid treatment that does not contain any toxic components, is possible. I made it. Furthermore, the present invention has been able to provide a fiber that has a high degree of molecular orientation, has a low boiling water shrinkage, and can be put to practical use as it is, from which the other composite components have been removed. .

  Hereinafter, the present invention will be described based on embodiments shown in the drawings. FIG. 1 shows a case where the flow in the composite spinning nozzle for controlling the fiber cross-sectional shape of the present invention is viewed from below. FIG. A shows a core-sheath type spinning nozzle, in which the core-sheath fiber is spun in a configuration in which the component A is the core and the component B is the sheath. FIG. B is a side-by-side type spinning nozzle, in which the A component 3 and the B component 4 are arranged in parallel, and are used for manufacturing a modified cross-section fiber. C to E are multilayer composite spinning nozzles, which are used for the production of ultrafine fibers and irregular cross-section fibers. FIG. 6C shows a multiple parallel type nozzle, in which the A component 5 and the B component 6 are aligned in parallel. FIG. D shows a multi-core type nozzle or a sea-island spinning nozzle, where A component 7 is an island component and B component 8 is a sea component. The sea component can be dissolved and removed with a solvent to obtain A component ultrafine fibers. FIG. E shows a radial nozzle in which the A component 9 is radially arranged and the B component 10 is arranged so as to fill the gap. If the A component and the B component in FIG. E are reversed and the radial component is the B component, a deformed ultrafine fiber of the A component can be obtained. The cross section of the composite filament spun using these spinning nozzles was substantially the same as that shown in FIG.

  Examples of the present invention will be specifically described below with reference to Tables 1 and 2. As a component A of the composite fiber in the present invention, unit name MA-2103 manufactured by Unitika Co., Ltd., which is polyethylene terephthalate having an intrinsic viscosity of 0.68, is referred to as PET. As the block copolymer of the composite fiber which is the component B in the present invention, as a block copolymer in which polystyrene blocks are bonded to both ends of the ethylene / propylene copolymer block, trade names Septon 2063 and 2002, 2007, 2104 manufactured by Kuraray Co., Ltd. These are denoted as SEPS-1, SEPS-2, SEPS-3, and SEPS-4, respectively. Table 1 shows the styrene content and melt flow rate of the four types of block copolymers. For reference, instead of the block copolymer, the melt flow rate is 30 g / 10 min polypropylene under the measurement conditions of 230 ° C. and 2.16 kgf, trade name PM900A manufactured by Sun Allomer Co., Ltd., and 18 g at the measurement conditions of 200 ° C. and 5 kgf. The product name 679 manufactured by PS Japan Co., Ltd., which is polystyrene of / 10 min, is referred to as PP and PS, respectively. In Examples 1 to 4 and Comparative Examples 1 to 3, composite spinning was performed using PET as the core component of the composite fiber and the four types of polymers shown in Table 1 as the sheath component. The polymer of each component of the core-sheath was melted at a cylinder temperature of 285 ° C. and 240 ° C., respectively, and the temperature of the core-sheath composite nozzle was 290 ° C. The discharge rate at this time was 5 cc / min. Further, in Reference Examples 1 and 2, PP and PS were used in place of the block copolymers shown in Table 1, respectively, and composite spinning was performed under the same conditions as in the Examples. Further, as Reference Example 3, melt spinning with PET alone was performed at a cylinder temperature of 285 ° C. and a nozzle temperature of 290 ° C.

Hereinafter, the evaluation items performed in each example will be described. With respect to the spinnability, the case where the prototype yarn was obtained at the set winding speed was marked as “◯”, and the case where the yarn was broken on the spinning line during winding and the prototype yarn was not obtained was marked as “X”. For single fiber separability, the case where the wound composite fiber could be separated into single fibers only by mechanical action was marked as ◯. Was marked as x when fractured or significantly plastically deformed.
Regarding the hot boiling water shrinkage, the filament cut to have a fiber length of 120 mm was immersed in 94 ° C. water for 2 minutes, the fiber length L was measured at room temperature, and the boiling water shrinkage (%) = {(120− L) / 120} × 100. The measurement was performed 5 times or more for each sample, and an average value was adopted. Regarding the dissolution removal rate, the sample with a dry weight W0 before soaking was immersed in limonene (D-limonene manufactured by Yashara Chemical Co., Ltd.) kept at 40 ° C. for 15 minutes, and then the dry weight W after soaking was measured and dissolved and removed. The ratio (%) = {(W0−W) / W0} × 100. From Table 2, in Example 1-4, the solvent was almost completely removed. One feature of the present invention is that the B component can be removed by solvent treatment at such a low temperature and short time. In the composite fiber with PP of Reference Example 1, the solvent could not be removed. The birefringence of the core component is determined by measuring the refractive index anisotropy of the composite fiber after dissolution and removal with an interference microscope when it can be determined that the B component has been dissolved and removed almost completely by the result of the dissolution and removal rate. Calculated. At this time, the average refractive index was calculated and converted to the fiber density by the method described in the following document.
J. Shimizu
and T. Kikutani, “Polyester 50 years of Achievement,
Ed. J. Hearle ”, p.166 (1993)

  Table 2 shows the core-sheath ratio and the melt spinning speed in Examples 1 to 4, Comparative Examples 1 to 3, and Reference Examples 1 to 3, and the results of the evaluation items. From this table, in the constitutional range of the component B of Example 1-4, there is high-speed spinnability (spinning property), single fiber separation property, dissolution removal property, and the boiling water shrinkage of the obtained polyethylene terephthalate filament is 6%. The birefringence of the filament is 0.09 or more and the degree of molecular orientation is high. In Comparative Example 1, even if the blending of Component B is good, single fiber separation is poor at low speed spinning, and the boiling water shrinkage is as large as 58.3%. In Comparative Example 2, when the melt flow rate of Component B is small, the high speed spinning speed is not reached due to yarn breakage. Comparative Example 3 is a case where the styrene content of the B component is high and the melt flow rate of the B component is small, and the high speed spinning speed is not reached due to yarn breakage.

  Reference Example 1 is a case where polypropylene is used as the B component, and the dissolution and removal properties are poor. Reference Example 2 is a case where polystyrene is used as the B component, and despite the winding speed of 6 km / min, the obtained polyethylene terephthalate filament has a high boiling water shrinkage and a low birefringence, so that the molecular orientation Degree and crystallinity are small. In Reference Example 3, component B was also polyethylene terephthalate, that is, a case of polyethylene terephthalate single-spinning instead of composite spinning, and it should be noted that in comparison with Example 2 having the same winding speed, The resulting polyethylene terephthalate filament has a high boiling water shrinkage and a low birefringence, and therefore has a low degree of molecular orientation and crystallinity. Further, in Example 3 of the present invention, high speed spinning up to 7 km / min is possible, in which case the degree of molecular orientation is further improved and the boiling water shrinkage is further reduced.

  The dependence of the birefringence, density, and boiling water shrinkage on the winding speed in the polyethylene terephthalate fiber obtained in the present invention is shown in Table 3, FIG. 2, FIG. 3, and FIG. In the figure, ◯ indicates core-sheath composite spun PET / SEPS-2 (77/28 weight ratio), Δ indicates core-sheath composite spun PET / PS (75/25 weight ratio), and □ indicates This is the case of PET single spinning. From Table 3, FIG. 2, FIG. 3 and FIG. 4, the core-sheath composite spun PET / SEPS-2 (77/28 weight ratio) (circle mark) of the present invention is PET / PS (triangle mark) or PET single spinning. It can be seen that the birefringence and density are large and the boiling water shrinkage ratio is small by high speed spinning as compared with (□).

  FIG. 5 shows a scanning electron micrograph of the side surface of the core-sheath composite fiber PET / SEPS-2 (77/28 weight ratio) obtained at a winding speed of 6 km / min. FIG. 6 shows a scanning electron micrograph of the side of the fiber from which the sheath component SEPS-2 has been removed by immersing the composite fiber of FIG. 5 in 40 ° C. limonene for 15 minutes. As described above, the fiber cross section of the composite fiber obtained in the present invention was controlled by the solvent, and the fiber diameter was reduced.

The polyethylene terephthalate fiber of the present invention is used as a raw material for various textile products such as woven fabrics, knitted fabrics and nonwoven fabrics.

The schematic diagram which looked at the composite spinning nozzle of this invention from the bottom. The graph which shows the winding speed dependence of the birefringence in the polyethylene terephthalate filament obtained by this invention. The graph which shows the winding speed dependence of the density in the polyethylene terephthalate filament obtained by this invention. The graph which shows the winding rate dependence of the boiling-water shrinkage | contraction rate in the polyethylene terephthalate filament obtained by this invention. The scanning electron micrograph of the side surface of the core-sheath composite filament obtained in the present invention. FIG. 6 is a scanning electron micrograph of the side surface of the filament from which the sheath component has been removed by immersing the filament of FIG. 5 in a solvent.

Explanation of symbols

1, 3, 5, 7, 9: A component, 2, 4, 6, 8, 10: B component.

Claims (7)

A component is polyethylene terephthalate,
B component is a block copolymer composed of polystyrene block and polyolefin block. When B component is 100%, the former block is 5% or more and 60% or less, and the latter block is 95% or less and 40% or more. ,
B component has a melt flow rate of 3 g / 10 min or more,
In a weight percentage, the A component is 50% or more and 95% or less, and the B component is 5% or more and 50% or less, and the molten polymer of A and B components is extruded from the composite spinning nozzle,
A method for producing a cross-sectional shape control fiber, wherein high-speed spinning is performed at a spinning speed of 5 km / min or more.     The manufacturing method of the cross-sectional form control fiber of Claim 1 whose said polyolefin component of B component is an ethylene / propylene copolymer.   The method for producing a cross-sectional shape control fiber according to claim 1, wherein the composite spinning nozzle is a core-sheath type composite spinning nozzle having a B component as a sheath and an A component as a core.   The method for producing a cross-sectional shape control fiber according to claim 1, wherein the composite spinning nozzle is a composite spinning nozzle in which an A component and a B component are arranged side by side.   The method for producing a cross-sectional shape control fiber according to claim 1, wherein the composite spinning nozzle is a sea-island fiber spinning nozzle or a split fiber spinning nozzle in which the component A is an ultrafine fiber component.   The cross-sectional shape control fiber of Claim 1 obtained by the composite spinning which consists of said A component and said B component. The B component consists of a filament mainly composed of the A component obtained by removing with a solvent mainly composed of limonene, the birefringence of the filament is 0.09 or more, and the boiling water shrinkage is 6% or less. The cross-sectional shape control fiber according to claim 1.

Images