JP2015140487A - Core-sheath type composite fiber and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core-sheath type composition fiber desirably available for industries having higher strength level than ever before and good in spinning property or quality while having fiber surface property of polyphenylene sulfide.SOLUTION: The core-sheath type composite fiber has a core component consisting of polyester and a sheath component consisting of a blend polymer of polyester and polyphenylene sulfide where the polyester in the sheath component is fine dispersed with dispersion diameter of 0.5 μm or less and strength is 5 to 8 cN/dtex.

Description

  The present invention relates to a core-sheath type composite fiber composed of polyphenylene sulfide and polyester and a method for producing the same. More specifically, the present invention relates to a core-sheath type composite fiber having a fiber surface characteristic of polyphenylene sulfide particularly suitable for industrial materials and excellent in physical characteristics, and a method for producing the same.

  Polyphenylene sulfide has excellent properties such as heat resistance, chemical resistance, flame retardancy and electrical insulation, and is known as a high-performance engineering plastic used in harsh environments. Also in the field of fibers, polyphenylene sulfide is taking advantage of the characteristics of its material and its applications are being expanded, but the properties of multifilament currently in practical use are used for industrial applications with a strength of about 5 cN / dtex. Currently, only relatively low strength fibers are obtained (see Patent Document 1 and Patent Document 2).

  In addition, polyphenylene sulfide resin is more expensive than general industrial polymers, and it is required to reduce the price while maintaining the characteristics of polyphenylene sulfide. For this reason, attempts have been made to improve mechanical properties and economic efficiency by combining with polymers such as polyamide and polyester that are generally used as industrial fibers from the past.

  Conventionally, a core-sheath type composite fiber in which the core component is a blend polymer of polyester and polyphenylene sulfide and the sheath component is polyphenylene sulfide has been proposed (see Patent Document 3), and the core component is polyester and the sheath component is A core-sheath composite fiber composed of a blend polymer of polyphenylene sulfide and polyester has been proposed (see Patent Document 4). However, the strengths of these core-sheath type composite fibers are both less than 5 cN / dtex and the strength level of polyphenylene sulfide single yarn, which is not sufficient from the viewpoint of physical properties.

  Further, in order to solve the above problems, a core-sheath type composite fiber has been proposed in which the core component is polyethylene terephthalate, the sheath component is polyphenylene sulfide, and the intermediate layer is composed of a blend polymer of polyethylene terephthalate and polyphenylene sulfide. (See Patent Document 5). According to this proposal, since the strength is improved to 6 cN / dtex and the intermediate layer is made of a blend polymer, a core-sheath type composite fiber having excellent peel resistance and applicable to industrial use is obtained. Due to the restrictions on the equipment and the spinning conditions for forming a layer structure, it has not yet been possible to obtain a stable yarn production and quality.

  Because of the property that the spinning temperature in composite spinning sets the melting temperature in accordance with the polymer having the higher melting point due to its equipment configuration, for the low melting side polymer to be composited, the spinning temperature is higher than the normal stable spinning conditions. This is presumably because the temperature has to be set and due to problems such as a decrease in physical properties due to delamination between layers due to problems of compatibility between polymers.

JP-A-57-143518 JP 2009-185438 A JP-A-2-99614 JP 2010-59580 A JP-A-4-327214

  Therefore, the object of the present invention has been achieved as a result of studying the above-described problems in the prior art as a solution, and has the fiber surface characteristics of polyphenylene sulfide, and has an unprecedented strength level, excellent yarn-making property and quality. Another object of the present invention is to provide a core-sheath type composite fiber that can be suitably used for industrial use.

  The present invention is intended to achieve the above object, and the core-sheath type composite fiber of the present invention has a core component made of polyester, a sheath component composed of a blend polymer of polyester and polyphenylene sulfide, and a strength of 5 It is a core-sheath type composite fiber of ˜8 cN / dtex.

  According to the preferable aspect of the core-sheath-type composite fiber of this invention, the mass ratio of the said core component and a sheath component is 20: 80-80: 20.

  According to the preferable aspect of the core-sheath-type composite fiber of this invention, the blend ratio of the polyester in the said sheath component is 0.1-15 mass%.

  According to a preferred embodiment of the core-sheath composite fiber of the present invention, the polyester in the sheath component is finely dispersed with a dispersion diameter of 0.5 μm or less.

  According to a preferred embodiment of the core-sheath type conjugate fiber of the present invention, the core-sheath type conjugate fiber has a total fineness of 300 to 2000 dtex, a single fiber fineness of 3 to 25 dtex, and an elongation of 10 to 25%. Moreover, the dry heat shrinkage at a temperature of 150 ° C. is 3 to 15%.

  The production method of the core-sheath type composite fiber of the present invention comprises a core-sheath composite die comprising a blend polymer melt-kneaded with polyphenylene sulfide so that the dispersion diameter of polyester is 0.5 μm or less as a sheath component, and a core component polyester. , Melt spinning at a temperature of 280 to 300 ° C., and stretching at a draw ratio of 3.5 to 5.0 times without winding once.

  According to the present invention, as described below, it is possible to obtain a core-sheath type composite fiber having the surface characteristics of polyphenylene sulfide fiber suitable for industrial materials with high strength and good quality at high production efficiency and at low cost. It becomes.

  In the core-sheath type composite fiber of the present invention, the blend ratio and the dispersion diameter of the polyester in the sheath component are set to the above-described preferable specific ranges, so that the fiber surface characteristics can flow when melted while having the function of polyphenylene sulfide. By improving the properties, the spinning conditions can be set within a specific range, specifically at a low spinning temperature that is not set under the conventional polyphenylene sulfide spinning conditions, and within a spinning temperature range where the thermal decomposition of the polyester can be minimized. Preferred compounding can be achieved under the spinning conditions described above.

  Next, the core-sheath composite fiber of the present invention and the production method thereof will be described in detail.

  The core-sheath type composite fiber of the present invention is a core-sheath type composite fiber having a core component made of polyester, a sheath component composed of a blend polymer of polyester and polyphenylene sulfide, and a strength of 5 to 8 cN / dtex.

  In the core-sheath type composite fiber of the present invention, it is necessary that the core component is made of polyester and the sheath component is composed of a blend polymer of polyester and polyphenylene sulfide. Polyester includes a polymer obtained using a diol component and a terephthalic acid component. Examples of the diol component include ethylene glycol, 1,4 butanediol, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, Examples thereof include neopentyl glycol, diethylene glycol, polyethylene glycol, cyclohexane dimethanol, and 2,2-bis (2'-hydroxyethoxyphenyl) propane, and derivatives thereof having ester forming ability.

  1,4-butanediol and its ester-forming derivative, trimethylene glycol and its ester-forming derivative, ethylene glycol or its ester-forming derivative, and terephthalic acid or its ester-forming ability Polybutylene terephthalate, polytrimethylene terephthalate, and polyethylene terephthalate obtained by polycondensation of derivatives, particularly polyethylene terephthalate, are particularly preferred because they are excellent in physical properties and thermal stability and are relatively inexpensive polymers.

  In addition, within the range that does not impair the characteristics, acid components such as isophthalic acid, adipic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, butanediol, hexanediol, diethylene glycol are included in the polymer. A diol component such as neopentyl glycol and 1,4 cyclohexanediol can be copolymerized.

  In addition, polymers include inorganic materials such as titanium oxide, calcium carbonate, kaolin and clay for the main purpose of matting, UV absorbers such as benzophenone and benzotriazole for the purpose of improving weather resistance, antioxidants, and A radical scavenger and the like can be contained.

  The blend polymer constituting the sheath component needs to be a blend polymer of the polyester and polyphenylene sulfide. Since the object of the present invention is a core-sheath type composite fiber having the function of polyphenylene sulfide, it is natural to use polyphenylene sulfide, but in order to improve the compatibility with the polyester as the core component, the polymer to be blended is polyester. It is necessary to be.

  Moreover, it is preferable that the ratio of the polyester in the blend polymer of a sheath component is 0.1-20 mass%, More preferably, it is 0.2-15 mass%, More preferably, it is 0.3-10 mass% is there.

  Moreover, it is preferable that the dispersion diameter of the polyester in a blend polymer is 0.5 micrometer or less, More preferably, it is 0.05-0.4 micrometer, More preferably, it is 0.1-0.3 micrometer. When the ratio of the polyester in the blend polymer is increased, the characteristics of polyphenylene sulfide tend to be lowered.

  Moreover, it is preferable that the dispersion diameter of polyester is made into the said range also from the point of the interface peeling of a sheath part and a core part. The dispersion diameter of the polyester in the blend polymer is related to the fluidity of the blend polymer in melt spinning, and if the dispersion diameter is large, the physical properties decrease or the stability of the yarn-making property and characteristics due to the generation of voids between the resins, The above range is preferable in terms of quality.

  The core-sheath type composite fiber of the present invention needs to have a strength of 5 to 8 cN / dtex, preferably 6 to 7.5 cN / dtex, and more preferably 6.5 to 7.5 cN / dtex. is there. Higher strength can reduce the number of fibers in higher-order applications, which is advantageous in terms of downsizing, weight reduction, and economy, but the present invention is applied to those whose strength exceeds 8 cN / dtex. Even if it does, it becomes difficult to obtain the yarn-making property and quality stably.

  Moreover, the core-sheath-type conjugate fiber of the present invention is intended for use in industrial applications, and the total fineness is preferably 200 to 2500 dtex, more preferably 300 to 2000 dtex. Moreover, it is preferable that single fiber fineness is 3-25 dtex, More preferably, it is 4-20 dtex. Moreover, it is preferable that elongation is 10-25%, More preferably, it is 12-22%. The dry yield is preferably 15% or less, more preferably 3 to 10%. By setting the above-mentioned various characteristics within the above ranges, a core-sheath type composite fiber that is easy to handle and can be suitably used for industrial applications and has excellent dimensional stability and toughness can be obtained.

<Method for producing core-sheath type composite fiber>
The core-sheath type composite fiber of the present invention can be produced by the following method.

  First, regarding polyphenylene sulfide, a polyphenylene sulfide pellet having a melt flow rate (MFR) of preferably 50 to 600 is preferably dried at a temperature of 140 to 180 ° C. for about 2 to 24 hours in order to remove foreign substances having a low boiling point. The melt flow rate (MFR) here is a parameter indicating the melt flowability of the polymer measured by the ASTM D1238-82 method when the set temperature is 316 ° C. and the load is 5 kgf. The polyphenylene sulfide used in the present invention may contain a small amount of other additives to such an extent that there is no substantial problem.

  Next, for polyester, for example, terephthalic acid or dimethyl terephthalate and ethylene glycol are used for esterification or transesterification. When the transesterification reaction is performed, a transesterification reaction catalyst such as magnesium acetate, calcium acetate, cobalt acetate, and manganese acetate can be used. At this time, antimony trioxide, which is a polymerization catalyst, can also be added.

  When performing the esterification reaction, by-products of diethylene glycol can be suppressed by adding an appropriate amount of an alkali metal such as potassium hydroxide. After the esterification reaction and the transesterification reaction are substantially completed, it is preferable to add a polymerization catalyst such as germanium dioxide antimony trioxide, a titanium alkoxide, a titanium chelate compound, or a phosphorus compound.

  Phosphoric acid or the like can be added as a phosphorous compound from the standpoint of inhibiting the production of foreign matter, but this may also be delayed due to the deactivation of the polymerization catalyst, and is adjusted as appropriate according to the polymerization catalyst and conditions. Need to be added. Moreover, as other additives, various additives such as a cocatalyst and various particles such as titanium oxide, an antioxidant and an antistatic agent can be added as necessary. The polymerization reaction can be appropriately set in consideration of the target intrinsic viscosity and polymerization reaction time.

  In the solid phase polymerization, the chip can be temporarily converted to a solid phase polymerization with an intrinsic viscosity of 0.5 to 0.8. As for the solid phase polymerization method, it is preferable to perform solid phase polymerization at a temperature not higher than the melting point of the polyester resin composition at a vacuum degree of 20 Pa or lower from the viewpoint of obtaining a target intrinsic viscosity and reducing the moisture content of the chip. is there. The intrinsic viscosity of the polyester chip after solid state polymerization is preferably 1.0 to 1.5, more preferably 1.1 to 1.4. By setting the intrinsic viscosity within this range, a core-sheath composite fiber having physical properties suitable for industrial use can be obtained.

  In the production of the core-sheath type composite fiber of the present invention, the blend polymer as the sheath component may be blended in a spinning machine or previously melted and kneaded with polyester and polyphenylene sulfide, and then converted into a core-sheath composite fiber from the composite spinning machine. This is a preferred embodiment. As the melt kneading method, a heat melt kneading apparatus can be used. As the heat melt kneading apparatus, a single screw extruder, a twin screw extruder and a combination twin screw extruder, a kneader / ruder, or the like is used. However, by using a twin screw extruder, the dispersed diameter of the polyester in the blend polymer of the sheath component can be made fine. More preferably, a twin screw extruder having two or more kneading zones is used. Thus, it is preferable to set the conditions of the spinning device so that the dispersion diameter of the blend polymer of the sheath component is 0.5 μm or less, more preferably 0.05 to 0.4 μm, still more preferably 0.1 ~ 0.3 μm.

  Next, in order to obtain a core-sheath type composite fiber, the polyester and the blend polymer are melted by respective extruders using a composite spinning device, and are spun from the core-sheath composite base at a spinning temperature of 80 to 300 ° C. The melting point of polyphenylene sulfide is 285 ° C., and the spinning temperature is usually 310 ° C. or higher. However, the blend polymer having a dispersion diameter of 0.5 μm or less according to the present invention improves fluidity at a lower temperature. Therefore, stable spinning is possible at the above spinning temperature. The yarn spun from the fine hole of the die is passed through a heating cylinder installed immediately below the die, and then cooled and solidified by blowing cold air. As the die, a normal zigzag or annular arrangement in which the die pores are arranged can be used.

  The conditions of the heating cylinder can be appropriately adjusted according to the size and yarn of the spinning machine, but preferably the length is in the range of 5 to 50 cm and the temperature is set in the range of 280 to 330 ° C. Is preferred. The cooling is preferably performed by blowing cooling air having a temperature of 10 to 30 ° C. at a speed of 20 to 50 m / min.

  Next, an oil agent is applied to the cooled and solidified yarn, and the yarn is taken up by a take-up roll that rotates at a predetermined speed. The oil agent can be applied using a method such as roller oil supply or guide oil supply, and the oil agent used is an aqueous emulsion oil agent or a non-aqueous oil agent mainly composed of a smoothing agent, an activator and an emulsifier. Can do. Examples of the oil composition include ester compounds formed from polytetramethylene glycol having an average molecular weight of 600 to 6000, a dibasic acid, and a monovalent fatty acid. A polyether ester having an average molecular weight of 2000 to 15000 can be contained, but is not limited thereto, and a pH adjuster such as an alkylene oxide adduct of an alkylamine, an antioxidant, an ultraviolet absorber and fluorine as necessary. Other additives such as compounds can be added.

  The temperature of the take-up roll is preferably 20 to 70 ° C., and the take-up speed is preferably 400 to 1500 m / min, more preferably 500 to 1200 m / min. By making the temperature and take-up speed of the take-up roll within this range, it becomes possible to stably spin the composite spun yarn, and it is suitable for stably producing the core-sheath type composite fiber satisfying the strength range of the present invention. An appropriate stretching ratio can be set.

  Next, the take-up yarn is wound around the feed roll without being wound once in order to stabilize the quality and yarn-making property, and after the pre-stretch is applied to the yarn between the take-up roll and the feed roll, Multi-stage stretching is performed by a plurality of stretching rolls installed. Here, the pre-stretch is preferably 1 to 10%, more preferably 2 to 8%. Moreover, it is preferable to control the temperature of a feed roll at 20-120 degreeC.

  Next, the first stage of stretching is performed between the feed roll and the first stretching roll. The temperature of the first draw roll is preferably 80 to 120 ° C., and the draw ratio is preferably 2 to 4 times, preferably as high as possible without causing single yarn breakage. The first-stage drawn yarn is subjected to second-stage drawing between the second drawing rolls. A 2nd extending | stretching roll is set to the temperature range of 180-240 degreeC. The second stage draw ratio is preferably set to 1.05 to 1.4 times. At this time, it is preferable from the viewpoint of yarn forming property that the yarns are converged between the first drawing roll and the second drawing roll using a focusing air nozzle. If necessary, three-stage stretching using a third stretching roll can also be performed. The temperature of the 3rd extending | stretching roll in this case shall be the same temperature range as the said 2nd extending | stretching roll, and is normally set to a temperature higher than a 2nd extending | stretching roll. In addition, it is preferable that the third stage draw ratio is usually set by dividing the second stage draw ratio and setting the second stage draw ratio higher than the third stage draw ratio.

  The overall draw ratio is preferably 3.5 to 5 times, more preferably 4 to 5 times. The drawn yarn is then subjected to relaxation heat treatment by a relaxation roll. The relaxation roll is set to a non-heated or 150 ° C. or lower temperature. The relaxation rate is preferably 2 to 10%, more preferably 4 to 8%.

  Then, it is a preferable aspect to provide the entanglement by fluid treatment before winding the yarn. In order to impart entanglement, a nozzle for fluid treatment, a flow rate of fluid during treatment, a winding tension, and the like may be appropriately set. By setting the number of entanglement to 5 to 20 / m, The yarn can be made excellent in process passability in high-order processing.

  According to the present invention, it is possible to obtain a core-sheath type composite fiber having the surface characteristics of polyphenylene sulfide and having a higher strength than conventional ones. Therefore, the technology of the present invention has higher strength than conventional polyphenylene sulfide fiber products and can reduce the number of components, thereby enabling downsizing and weight reduction, and binding for various motors for automobiles, home appliances, and industries. It is effective in the field of industrial materials such as yarns, Velcro (registered trademark), cords for special hoses, and filters.

  Next, an Example demonstrates the core-sheath-type composite fiber of this invention, and its manufacturing method in detail. The definition and measuring method of each characteristic in the present invention are as follows.

(1) Intrinsic viscosity (IV) of polymer:
Add 10 ml of orthochlorophenol to 0.8 g of sample, heat and dissolve at 160 ° C. for 10 minutes, cool, and measure the relative viscosity ηr of the solution at 25 ° C. using an Ostwald viscometer. Intrinsic viscosity (IV) was calculated according to the formula.
IV = 0.0242ηr + 0.02634.

(2) Total fineness:
According to JIS L1013 (2010) 8.3.1 A method, the positive fineness was measured at a predetermined load of 0.045 cN / dtex to obtain the total fineness.

(3) Number of single fibers:
Measured by the method of JIS L1013 (2010) 8.4, and the number of single fibers was calculated.

→ It is stated that the number of filaments in JIS is counted.
(4) Single fiber fineness:
The single fiber fineness was calculated by dividing the total fineness by the number of single fibers.

(5) Strength and elongation:
Strength and elongation were measured under the constant speed elongation conditions shown in JIS L1013 8.5.1 (2010) standard time test. Using “TENSILON” UCT-100 manufactured by Orientec Co., Ltd., the sample was measured at a grip interval of 25 cm and a pulling speed of 30 cm / min. The elongation was determined from the elongation at the point showing the maximum strength in the SS curve.

(6) 150 ° C. dry heat shrinkage:
By the method of JIS L1013 (2010) 8.18.2 b), the dry heat shrinkage rate was measured using a dryer heated to a temperature of 150 ° C.

(7) Number of confounding:
The number of entangled portions having a length of 1 mm or more was measured by a water immersion method and converted to the number per 1 m. Ten raw yarns were measured and indicated by the average value. A water immersion bath having a length of 70 cm, a width of 15 cm, a depth of 5 cm, and a partition plate provided at a position 10 cm from both ends in the longitudinal direction was used. The bath was filled with pure water, the raw yarn sample was immersed in water, and the number of entangled portions was measured.

(8) Yarn fluff:
A laser-type fluff detector was installed at a position 5 mm away from the roll installed between the stretching and relaxation heat treatment roll and the winder, and the number of fluff detected per 5 minutes was converted into the number per 20 km and displayed.

(9) Measurement of the core-sheath ratio of the composite fiber:
An ultrathin section in the cross-sectional direction of the composite fiber was prepared using an ultramicrotome (MT6000 type) manufactured by Sorvall. The ultrathin section was observed at 3000 times using a transmission electron microscope (Hitachi H800 type). The field of view was changed, photographs of 5 fields of view were taken, the core part and the sheath part were cut out for each photograph, the ratio of the core component and the sheath component was calculated by the weight method, and the average value of the 5 fields of view was taken as the core-sheath ratio.

(10) Measurement of dispersion diameter:
Ultra-thin sections were cut out from the fiber filaments in the direction perpendicular to the fiber axis, imaged by TEM (H-7100FA manufactured by Hitachi High-Technologies), and the average value of the dispersion diameters of 10 points arbitrarily selected at 40,000 times was obtained.

(11) Heat resistance evaluation:
The fibers to be evaluated were sampled in the shape of a cake and processed in an oven set at a temperature of 220 ° C. in a free state for 168 hours, and the retention rate was calculated from the strength of the sample before and after the treatment. The strength was measured according to the above (5).

(12) Chemical resistance:
The fibers to be evaluated were sampled in the form of a cake, treated with a solution of 48% sulfuric acid and 30% sodium hydroxide heated to a temperature of 60 ° C. for 168 hours, and the retention rate was calculated from the strength before and after the treatment. The strength was measured according to the above (5).

[Example 1]
35. Toray polyphenylene sulfide chip having an MFR of 200 dried at 150 ° C. under vacuum for 10 hours, 82.5 kg of high purity terephthalic acid (Mitsui Chemicals) and ethylene glycol (Nippon Shokubai Co., Ltd.) 4 kg of slurry is charged in advance to an esterification reaction tank preliminarily charged with about 100 kg of bis (hydroxyethyl) terephthalate and maintained at a temperature of 250 ° C. and a pressure of 0.12 MPa over 4 hours. The esterification reaction was carried out, and 101.5 kg of this esterification reaction product was transferred to a polycondensation tank. Subsequently, 28 g of antimony trioxide, 20 g of manganese acetate, and 9 g of an aqueous solution of 85% by mass of phosphoric acid were added to the esterification reaction product. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was gradually heated from 250 ° C. to 290 ° C. and the pressure was reduced to 40 Pa. Both the final temperature and the time to reach the final pressure were 60 minutes. When the predetermined stirring torque is reached, the reaction system is purged with nitrogen, returned to normal pressure, the polycondensation reaction is stopped, discharged into cold water in a strand form, and immediately cut to obtain a polyethylene terephthalate chip with an IV of 0.7. It was. After the obtained polyethylene terephthalate chip was dried, solid phase polymerization was performed at a temperature of 210 ° C., and composite spinning was performed using a chip having an IV of 1.15.

  First, 97% by mass of polyphenylene sulfide chips and 3% by mass of polyethylene terephthalate chips were supplied to a vented twin-screw kneading extruder having two kneading zones heated to a temperature of 300 ° C., and a shear rate of 100 sec −1. Then, melt extrusion was performed at a residence time of 1 minute. The polymer temperature at the time of melt kneading was 300 ° C. A twin-screw kneading extruder was discharged into cold water in the form of a strand and immediately cut to obtain a polymer chip of 97% by mass of polyphenylene sulfide and 3% by mass of polyethylene terephthalate.

  Next, composite spinning was performed using polyethylene terephthalate as a core component and a blend polymer of polyphenylene sulfide and polyethylene terephthalate obtained by the kneading as a sheath component. Each chip was melted by an extruder, supplied to a composite spinning pack, and melt-spun at a spinning temperature of 290 ° C. so that a predetermined core-sheath ratio was 50/50 from the core-sheath composite die. In addition, a heating cylinder with a length of 30 cm is installed just below the base and set to a temperature of 300 ° C. After the yarn is cooled slowly, a temperature of 25 ° C. is used using a side blowing type cooling chimney. Then, it was cooled and solidified with cold air at 40 m / min, and then an aqueous emulsion oil was applied with an oil supply roll, and the spun yarn was taken up at a speed of 795 m / min.

  Subsequently, the spun yarn is stretched by 3% between the take-up roller and the feed roller, and then the first drawing is performed between the feed roller and the first drawing roller, and the first drawing roller and the second drawing are drawn. The second stage of stretching is performed between the rollers, a relaxation heat treatment of 2% is performed between the second stretching roller and the relaxation roller, and the yarn is entangled with the entanglement imparting device, and then wound with a winder Winded up. The surface temperature of each roller was set so that the take-up roller was normal temperature, the feed roller was 40 ° C., the first stretching roller was 100 ° C., the second stretching roller was 220 ° C., and the relaxation roller was 150 ° C. The rotation speeds of the first stretching roll and the second stretching roll were set so that the first stage stretching ratio was 3.56 times and the overall stretching ratio was 4.4 times.

  Table 1 shows the properties and evaluation results of the obtained core-sheath type composite fibers. The obtained core-sheath type composite fiber has improved fluidity of the blend polymer, can be melt-spun at a lower temperature than the spinning temperature of conventional polyphenylene sulfide, and the heat of polyethylene terephthalate. IV reduction due to decomposition can be suppressed. In addition, since the polyethylene terephthalate in the blend polymer is finely dispersed, there is no generation of voids in the blend polymer or peeling between the core-sheath layers even at a high draw ratio, and there is no fluff and good yarn production. there were.

[Examples 2 to 6]
As Table 1, it carried out like Example 1 except having changed into the blend polymer from which the core-sheath ratio, the blend ratio in the blend polymer of a sheath component, and a dispersion diameter differed. By setting various requirements so as to be within the specified range of the present invention, the fluidity of the blend polymer of the sheath component is improved and spinning and stretchability are improved. I was able to get good quality. The results are shown in Table 1.

[Examples 7 to 10]
As Table 2, it carried out like Example 1 except having changed into the blend polymer from which the core-sheath ratio, the blend ratio in the blend polymer of a sheath component, and a dispersion diameter differed. By setting various requirements so as to be within the specified range of the present invention, the fluidity of the blend polymer of the sheath component is improved and spinning and stretchability are improved. I was able to get good quality. The results are shown in Table 2.

[Comparative Examples 1-2]
The sheath component was used in the same manner as in Example 1 except that polyphenylene sulfide was used alone and as shown in Table 2, the conditions were adjusted to the spinning temperature and drawing conditions that allowed stable yarn production. Various characteristics are shown in Table 2. As in Comparative Examples 1 and 2, when the sheath component was polyphenylene sulfide alone, the spinning temperature was set to 315 ° C. because the fluidity was poor and the discharge stability and stretchability were poor when the spinning temperature was low. Due to the occurrence of this, the draw ratio had to be lowered, and only those with low physical properties could be obtained.

Claims (6)

  A core-sheath type composite fiber characterized in that the core component is made of polyester, the sheath component is composed of a blend polymer of polyester and polyphenylene sulfide, and the strength is 5 to 8 cN / dtex.   The core-sheath composite fiber according to claim 1, wherein the mass ratio of the core component to the sheath component is 20:80 to 80:20.   The core-sheath type composite fiber according to claim 1 or 2, wherein a blend ratio of the polyester in the sheath component is 0.1 to 15% by mass.   The core-sheath type composite fiber according to any one of claims 1 to 3, wherein the polyester in the sheath component is finely dispersed with a dispersion diameter of 0.5 µm or less.   The total fineness is 300 to 2000 dtex, the single fiber fineness is 3 to 25 dtex, the elongation is 10 to 25%, and the dry heat shrinkage at 150 ° C is 3 to 15%. The core-sheath type | mold composite fiber of any one of -4.   As a sheath component, the blend polymer melt-kneaded with polyphenylene sulfide so that the dispersion diameter of the polyester is 0.5 μm or less and the core component polyester are melt-spun at a temperature of 280 to 300 ° C. from the core-sheath composite die, and once A method for producing a core-sheath type composite fiber, which is drawn at a draw ratio of 3.5 to 5.0 times without being wound.