JP2015067919A - Polyarylene sulfide fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyarylene sulfide fiber that is extra fine and excellent in mechanical strength and to provide a method for producing the polyarylene sulfide fiber with good productivity.SOLUTION: The polyarylene sulfide fiber is a fiber composed of a polyarylene sulfide resin and having a diameter of 50 μm or less and the polyarylene sulfide resin has a sodium content in the range of 40-2,000 ppm. The method for producing the polyarylene sulfide fiber comprises electrospinning the polyarylene sulfide resin.

Description

  The present invention relates to an ultrafine polyarylene sulfide fiber and a method for producing the same.

  Various methods such as melt blow method, spun bond method, conjugate method, spinning method such as electrospinning method are known as polymer fiber production methods, but in the case of super engineering plastic represented by polyphenylene sulfide resin Only the fiber spinning method by the melt spinning method represented by the melt blow method and the spun bond method has been established. However, although a method of producing a polyphenylene sulfide resin fiber having a fiber diameter of submicron or less, that is, a nanoscale fiber diameter by the melt blow method or the spun bond method is excellent in productivity, a fiber diameter of 1 μm or less is stably produced in a large amount. Since the technology that can be produced in the future has not been established, it has not been put into practical use. Further, among the melt spinning methods, the conjugate method is capable of forming fibers of 100 nm or less, but requires a fiber splitting step, which is unsuitable for efficiency and has a problem of poor productivity.

  On the other hand, when the polymer dissolved in the solvent is dissolved in the electrolyte solution and extruded from the nozzle, a high voltage of several thousand to 30,000 volts is applied to the polymer solution, and the polymer solution is extremely fine due to the bending and expansion of the high-speed jet and the subsequent jet. The electrospinning method is known as a method for obtaining extremely fine fibers (see Patent Documents 1 and 2). However, since polyarylene sulfide resin (hereinafter sometimes referred to as PAS resin) cannot be dissolved in a solvent at room temperature, there is a problem that the electrospinning method cannot be applied by dissolving the resin. . Also known is a method in which a thermoplastic resin is melted and electrospun (Patent Document 3). However, since the polyarylene sulfide resin has a high volume resistivity value, even if the polyarylene sulfide resin is melted, the polyarylene sulfide resin that is extremely fine and excellent in mechanical strength is not necessarily stably mass-produced. could not.

Special table 2010-520386 JP 2012-122176 A JP 2010-189792 A

  The problem to be solved by the present invention is to provide a polyarylene sulfide fiber that is extremely fine and excellent in mechanical strength, and a production method that is capable of stably mass-producing the fiber and that is excellent in productivity.

  As a result of diligent efforts to solve the above problems, the present inventors have found that the polyarylene sulfide resin has a high volume resistivity, but if the polyarylene sulfide resin has a sodium concentration in a specific range, the melt By electrospinning (hereinafter sometimes referred to as melt electrospinning), it has been found that polyarylene sulfide fibers excellent in mechanical strength can be produced with high productivity, and the present invention has been solved.

That is, the present invention is a method for producing a fiber having a diameter of 50 μm or less comprising a polyarylene sulfide resin, wherein the polyarylene sulfide resin is kneaded at a temperature equal to or higher than the melting point to form a melt, and then the melt Electrospinning objects to obtain fibers,
The said polyarylene sulfide resin is related with the manufacturing method of the polyarylene sulfide fiber characterized by having a sodium content in the range of 40-2000 ppm.

  Further, the present invention provides a polyarylene sulfide resin comprising a polyarylene sulfide resin having a diameter of 50 μm or less, wherein the polyarylene sulfide resin has a sodium content in the range of 40 to 2000 ppm or less. Related to fiber.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method excellent in productivity which can mass-produce the polyarylene sulfide fiber excellent in mechanical strength very finely and the said fiber stably can be provided.

[Polyarylene sulfide fiber]
The polyarylene sulfide fiber of the present invention is a polymer fiber having a fiber diameter (diameter) of 50 μm or less, preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 800 nm or less. Further, the lower limit of the fiber diameter is not particularly limited, but is preferably 10 nm or more, and more preferably 50 nm or more.

  The fiber diameter is a fiber diameter measured by a scanning electron microscope. Specifically, for example, SEM is measured using an S-2380N type manufactured by Hitachi, Ltd.

  In the polyarylene sulfide fiber of the present invention, the aspect ratio represented by the fiber length / fiber diameter is preferably 2 or more, more preferably 10 or more, further preferably 100 or more, and 1000 or more. Most preferably.

[Production method of polyarylene sulfide fiber]
The polyarylene sulfide fiber of the present invention can be produced by electrospinning a melt of a specific polyarylene sulfide resin (hereinafter sometimes simply referred to as a melt). Details will be described below.
[Polyarylene sulfide resin]
The polyarylene sulfide resin used in the present invention has a resin structure having a repeating unit of a structure in which an aromatic ring and a sulfur atom are bonded. Specifically, the polyarylene sulfide resin has the following formula (1):

（式中、Ｒ^１及びＲ^２は、それぞれ独立して水素原子、炭素原子数１〜４のアルキル基、ニトロ基、アミノ基、フェニル基、メトキシ基、エトキシ基を表す。）で表される構造部位を繰り返し単位とする樹脂である。

(Wherein, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a nitro group, an amino group, a phenyl group, a methoxy group, or an ethoxy group). It is a resin having a structural site as a repeating unit.

Here, in the structural site represented by the formula (1), R ¹ and R ² in the formula are preferably hydrogen atoms from the viewpoint of the mechanical strength of the polyarylene sulfide resin. A compound bonded at the para position represented by the following formula (2) is preferable.

これらの中でも、特に繰り返し単位中の芳香族環に対する硫黄原子の結合は前記構造式（２）で表されるパラ位で結合した構造であることが前記ポリアリーレンスルフィド樹脂の耐熱性や結晶性の面で好ましい。

Among these, in particular, the bond of the sulfur atom to the aromatic ring in the repeating unit is a structure bonded at the para position represented by the structural formula (2). In terms of surface.

  Further, the polyarylene sulfide resin is not only the structural portion represented by the formula (1), but also the following structural formulas (3) to (6).

で表される構造部位を、前記式（１）で表される構造部位との合計の３０モル％以下で含んでいてもよい。特に本発明では上記式（３）〜（６）で表される構造部位は１０モル％以下であることが、ポリアリーレンスルフィド樹脂の耐熱性、機械的強度の点から好ましい。前記ポリアリーレンスルフィド樹脂中に、上記式（３）〜（６）で表される構造部位を含む場合、それらの結合様式としては、ランダム共重合体、ブロック共重合体の何れであってもよい。

The structural site represented by the formula (1) may be included in an amount of 30 mol% or less in total. In particular, in the present invention, the structural portion represented by the above formulas (3) to (6) is preferably 10 mol% or less from the viewpoint of heat resistance and mechanical strength of the polyarylene sulfide resin. In the case where the polyarylene sulfide resin contains a structural portion represented by the above formulas (3) to (6), the bonding mode thereof may be either a random copolymer or a block copolymer. .

  The polyarylene sulfide resin has the following formula (7) in its molecular structure.

で表される３官能性の構造部位、或いは、ナフチルスルフィド結合などを有していてもよいが、他の構造部位との合計モル数に対して、３モル％以下が好ましく、特に１モル％以下であることが好ましい。

May have a trifunctional structural site represented by the formula (1) or a naphthyl sulfide bond, but is preferably 3 mol% or less, particularly 1 mol%, based on the total number of moles with other structural sites. The following is preferable.

The physical properties of the polyarylene sulfide resin are not particularly limited as long as the effects of the present invention are not impaired, but are as follows.
(Sodium concentration)
The polyarylene sulfide resin used in the present invention is obtained by calcining the resin at 500 ° C., then calcining at 530 ° C. for 6 hours, and dissolving the ash obtained with hydrochloric acid. Atomic absorption photometer: AA-6300 (manufactured by Shimadzu Corporation) ) In the range of 2000 ppm or less, more preferably 500 ppm or less, and particularly preferably 250 ppm or less. On the other hand, the lower limit of the sodium concentration is in the range of 40 ppm or more, more preferably in the range of 50 ppm or more, and particularly preferably in the range of 70 ppm or more. The polyarylene sulfide resin having a sodium content within the above specified range is easily charged in the resin melt, and the spin distribution is stabilized due to the stable charge distribution during spinning, making it easy to control the fiber diameter. preferable.

(Melt viscosity)
The polyarylene sulfide resin used in the present invention preferably has a melt viscosity (V6) measured at 300 ° C. in the range of 5 to 1000 [Pa · s], and has a good balance between fluidity and mechanical strength. Therefore, the range of 5 to 100 [Pa · s] is more preferable, and the range of 5 to 50 [Pa · s] is particularly preferable.
(Non-Newtonian index)
The non-Newtonian index of the polyarylene sulfide resin used in the present invention is not particularly limited as long as the effects of the present invention are not impaired, but is preferably in the range of 0.90 to 2.00. When the linear polyarylene sulfide resin is used, the non-Newton index is preferably in the range of 0.90 to 1.50, and more preferably in the range of 0.95 to 1.20. Such a polyarylene sulfide resin is excellent in mechanical properties, fluidity, and abrasion resistance. However, the non-Newtonian index (N value) is measured by measuring the shear rate and shear stress using a capillograph at 300 ° C, the ratio of the orifice length (L) to the orifice diameter (D), and L / D = 40. These are values calculated using the following formula.

［ただし、ＳＲは剪断速度（秒^−１）、ＳＳは剪断応力（ダイン／ｃｍ^２）、そしてＫは定数を示す。］Ｎ値は１に近いほどＰＰＳは線状に近い構造であり、Ｎ値が高いほど分岐が進んだ構造であることを示す。

[Wherein SR represents a shear rate (second ⁻¹ ), SS represents a shear stress (dyne / cm ² ), and K represents a constant. The closer the N value is to 1, the closer the PPS is to a linear structure, and the higher the N value is, the more branched the structure is.

  The method for producing the polyarylene sulfide resin used in the present invention is not particularly limited. For example, 1) a dihalogenoaromatic compound and, if necessary, other copolymerization components are polymerized in the presence of sulfur and sodium carbonate. Method 2) A method of polymerizing a dihalogenoaromatic compound and, if necessary, another copolymer component in the presence of a sulfidizing agent in a polar solvent, 3) p-chlorothiophenol, and further necessary Examples of such a method include self-condensation with other copolymerization components, 4) a method of melt polymerization of a diiodo aromatic compound, elemental sulfur, and, if necessary, a polymerization inhibitor in the presence of a polymerization catalyst. Among these methods, the method 2) is versatile and preferable. In the reaction, an alkali metal salt of carboxylic acid or sulfonic acid or an alkali hydroxide may be added to adjust the degree of polymerization. Among the above methods 2), a hydrous sulfiding agent is introduced into a mixture containing a heated organic polar solvent and a dihalogeno aromatic compound at a rate at which water can be removed from the reaction mixture, and the dihalogeno aromatic compound and A method for producing a polyarylene sulfide resin by reacting with a sulfidizing agent and controlling the amount of water in the reaction system in the range of 0.02 to 0.5 mol relative to 1 mol of the organic polar solvent ( Japanese Patent Application Laid-Open No. 07-228699), a polyhaloaromatic compound, an alkali metal hydrosulfide and an organic acid alkali metal salt in the presence of a solid alkali metal sulfide and an aprotic polar organic solvent. 0.01-0.9 mol of organic acid alkali metal salt and 1 mol of water in the reaction system with respect to 1 mol of aprotic polar organic solvent A method of reacting while controlling the .02 mols (WO2010 / 058 713 pamphlet reference.) Is what is particularly preferably obtained by.

  The method for producing the polyarylene sulfide fiber of the present invention, first, the polyarylene sulfide resin, if necessary, together with additives such as antioxidants, antifoaming agents, preservatives, rust inhibitors, etc. In the temperature range above the melting point of the polyarylene sulfide resin, preferably in the temperature range above the melting point + 10 ° C, more preferably in the temperature range from the melting point + 10 ° C to the melting point + 100 ° C, more preferably from the melting point + 20 ° C to the melting point + 50 ° C. A melt is obtained by melt-kneading in a temperature range.

  The melt-kneading conditions are not particularly limited as long as the effects of the present invention are not impaired, but for example, the following conditions are preferable. For example, an apparatus used for melt kneading is not particularly limited, but it is preferably performed in a heating apparatus for melting polyarylene sulfide resin such as an extruder having a nozzle attached to the tip.

  Subsequently, the melt of the polyarylene sulfide resin is electrospun to obtain a fiber. A melt electrospinning method (hereinafter referred to as a melt electrospinning method) is not particularly limited as long as the effect is not impaired. For example, it is generally used as a single-screw or twin-screw extruder type spinning machine. There is a method in which the melt spinning apparatus is provided with a device for applying a high voltage generated by a high voltage generator to the nozzle part, and the polyarylene sulfide resin melt discharged from the nozzle part is spun while applying an electric field. Here, an outline of the melt electrospinning method will be described. The apparatus used in the melt electrospinning method of the present invention includes a needle-like nozzle that discharges a polyarylene sulfide resin melt supplied from an extruder or the like to which a high voltage from a high voltage generator is applied, and a formed poly It consists of a flat plate-shaped or drum-shaped collecting portion for collecting the arylene sulfide fiber, and an electrode having a potential opposite to that of the tip of the nozzle is also arranged in the collecting portion. As a result, an electric field acts on the polyarylene sulfide resin melt to which an electric charge has been applied, and a drawing force is generated, so that ultrafine fibers having a fiber diameter that cannot be achieved by conventional melt spinning can be formed.

  Furthermore, in order to stably mass-produce nanoscale ultrafine fibers in the present invention, it is preferable to perform electrospinning while blowing the melt of the polyarylene sulfide resin (hereinafter sometimes referred to as air blow type melted electrospinning). . As an apparatus used for such air blow type melt electrospinning, it is preferable that an air blow apparatus for discharging compressed air is additionally provided in the apparatus used for melt electrospinning, for example, as described in Patent Document 2 The air blow device that discharges the compressed air is arranged in the direction opposite to the insulating shielding plate as viewed from the nozzle and from the nozzle rather than the electrode ball, and the electrode ball, air blow device, tip of the nozzle, hole, and collecting part are arranged. The structure is preferably arranged in a substantially straight line in this order. By arranging in this way, the drawing force of a high-speed jet to the polyarylene sulfide resin melt by air blow is added, and nanoscale ultrafine fibers can be mass-produced more stably.

  The temperature of the spinning process is preferably a temperature that is sufficient for the polyarylene sulfide resin to melt from the viewpoint of suppressing gelation and is as low as possible. Generally, the temperature of the polyarylene sulfide resin discharged from the nozzle is preferably in the range of 250 to 350 ° C, more preferably in the range of 270 to 330 ° C. The spinning process is preferably performed in a nitrogen atmosphere.

  As long as the nozzle is made of a material to which voltage can be applied, one that is usually used for melt spinning can be used. For example, the discharge port diameter is 0.3 to 1.0 mmφ, and the discharge hole depth is 5.0 to The thing of about 30.0 mm can be used preferably. The cross-sectional shape of the fiber according to the present embodiment is not particularly limited, and is not limited to a normal circular cross section, but a triangular cross section, a quadrangular cross section, a Y-shaped cross section, a cross section, a C-shaped cross section, a hollow cross section, a rice field cross section, and the like. Can be adopted.

  The yarn discharged from the nozzle is generally cooled and wound by being exposed to cooling air having a wind speed in the range of 5 to 100 m / min after spinning. At this time, if necessary, an oil agent may be added as a sizing agent. The winding speed is not particularly limited, but is preferably in the range of 300 to 5000 m / min. In addition, the production process may be applied by a drawing method in which spinning is performed once in a state of low speed spinning or high speed spinning and a drawing process is performed using a known drawing machine, and a direct spinning drawing method in which a spinning process and a drawing process are continuously performed. May be.

  The conditions of melt electrospinning applied between the nozzle and the collecting portion are not particularly limited as long as the effects of the present invention are not impaired, but the applied voltage is preferably in the range of 5 to 70 kV, and more preferably in the range of 10 to 50 kV. Is more preferable. Further, the spinning distance is preferably in the range of 10 to 100 mm, and more preferably in the range of 30 to 80 mm. When converted to a voltage per unit distance, a range of 0.2 to 8 kv / cm is preferable. As a result, charges concentrate on the melt at the nozzle tip, and the centrifugal force applied to the melt is further amplified by the repulsive force of the charges. The melt discharged from the nozzle reaches the collecting section while being cooled, becomes ultrafine fibers, and is sucked onto the collecting section. In addition, the diameter of the fiber obtained by the melt electrospinning method depends on the applied voltage and distance between the nozzle and the collection part, the melt viscosity of the melt, the amount of gas generated, etc. It can be of any diameter.

In the nozzle, the nozzle pores are arranged in a normal zigzag arrangement or an annular arrangement, and the nozzle diameter is 70 to 150 kg / cm ² at the back of the nozzle, and the ratio between the discharge linear velocity from the nozzle orifice and the take-off velocity. What is necessary is just to design suitably so that the spinning draft defined by may be 20-50. A more preferable range of the pressure on the back surface of the nozzle is 90 to 110 kg / cm ² .

  Next, the spun fiber can be taken up by applying a fiber processing agent by a known method such as roller lubrication or guide lubrication, if necessary, and wound around a take-up roll that rotates at the predetermined speed. In addition, in order to stabilize the quality / spinning property, after winding around the feed roll without pre-winding, pre-stretching the fiber between the take-up roll and the feed roll, and then winding using a known multi-stage drawing method It can also be taken.

  The method for producing polyarylene sulfide fibers of the present invention can easily produce high-quality fibers having a uniform fiber diameter in which yarn breakage and the like are suppressed by employing the above-described melt electrospinning method. As a result, a fiber excellent in heat resistance, moldability, dimensional stability, mechanical strength and the like can be obtained.

  In addition, since the polyarylene sulfide fiber of the present invention also has various performances such as heat resistance and dimensional stability inherent in the polyarylene sulfide resin, for example, electrical properties such as connectors, printed circuit boards, and sealing molded products.・ As fibers used in the fields of automotive parts such as electronic parts, lamp reflectors and various electrical parts, interior materials for various buildings, aircraft and automobiles, precision parts such as OA equipment parts, camera parts and watch parts Can be used. More specifically, it can be suitably used for a separator used for a lithium ion battery or the like, or a filter used for a bag filter or the like. When used in these applications, the fiber according to the present embodiment may be used alone, or may be used in appropriate combination with other fibers.

  The present invention will be specifically described below with reference to examples. These examples are illustrative and not limiting.

1. Evaluation method (sodium concentration of polyphenylene sulfide resin)
The ash obtained by baking the polyphenylene sulfide resin produced in the synthesis example at 500 ° C. and then baking at 530 ° C. for 6 hours was dissolved in hydrochloric acid and measured with an atomic absorption photometer: AA-6300 (manufactured by Shimadzu Corporation). .

(Measurement of melt viscosity of polyphenylene sulfide resin)
The polyphenylene sulfide resin produced in the synthesis example was measured after holding for 6 minutes at 300 ° C., load: 1.96 × 10 ⁶ Pa, L / D = 10/1, using a flow tester CFT-500C manufactured by Shimadzu Corporation. did.

(Fiber diameter)
A platinum-palladium alloy was vapor-deposited on the polyphenylene sulfide fiber and observed with a scanning electron microscope (SEM Hitachi, Ltd., S-2380N type), and 100 arbitrary points were taken out and the fiber diameter was measured (magnification: 10,000 times).

(Tensile properties)
This was performed according to JIS L-1015.
(Average fiber diameter)
The said fiber diameter is a fiber diameter measured with a scanning electron microscope, and measured using SEM Hitachi Ltd. S-2380N type | mold etc. The measurement calculated | required the average value from the measurement result of a total of 100 fibers in arbitrary several side surfaces.

(Thread break)
The thread breakage during the production of polyarylene sulfide fibers was evaluated. For evaluation, five sets of 300 g of the polymer in total were produced, and the average time until the occurrence of one yarn breakage (time during which continuous spinning was possible) was calculated (minute / time).

(Synthesis example 1) Production of PPS resin In an autoclave equipped with a stirrer and a valve at the bottom, 8267 g (70.00 mol) of 47.5% sodium hydrosulfide aqueous solution, 2925 g (70.20 mol) of 96% sodium hydroxide, N -Methyl-2-pyrrolidone (NMP) 13860.00 g (140.00 mol), sodium acetate 2187 g (26.67 mol), and ion-exchanged water 10500 g were charged, and the reaction was continued for about 3 hours up to 240 ° C. through nitrogen at normal pressure. After gradually heating and distilling 14740 g of water and 280.0 g of NMP, the reaction vessel was cooled to 160 ° C. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.08 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.023 mol per mol of the alkali metal sulfide charged.

  Next, 10324 g (70.24 mol) of p-dichlorobenzene (p-DCB) and 6452 g (65.17 mol) of NMP are added, the reaction vessel is sealed under nitrogen gas, and the mixture is stirred at 240 rpm with a temperature of 200 to 250 ° C. The temperature was raised to 0.8 ° C. at a rate of 0.8 ° C./min and held at 250 ° C. for 70 minutes. Next, the temperature was raised from 250 ° C. to 278 ° C. at a rate of 0.8 ° C./min, and maintained at 278 ° C. for 78 minutes. The extraction valve at the bottom of the autoclave was opened, the contents were flushed into a vessel equipped with a stirrer over 15 minutes while being pressurized with nitrogen, and stirred for a while at 250 ° C. to remove most of the NMP.

  The obtained solid and 76 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70 ° C. for 30 minutes, and then suction filtered through a glass filter. Next, 76 liters of ion-exchanged water heated to 70 ° C. was poured into a glass filter, and suction filtered to obtain a cake.

  The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and the interior of the autoclave was replaced with nitrogen, and then the temperature was raised to 192 ° C. and held for 30 minutes. Thereafter, the autoclave was cooled and the contents were taken out.

  The contents were subjected to suction filtration with a glass filter, and then 76 liters of ion-exchanged water at 70 ° C. was poured into the contents, followed by suction filtration to obtain a cake. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain dry PPS resin granules. The obtained PPS resin (1) had a sodium concentration of 520 ppm and a melt viscosity of 12 Pa · s.

(Synthesis example 2) Manufacture of PPS resin Instead of "After the inside of an autoclave was substituted with nitrogen, it heated up to 192 degreeC and hold | maintained for 30 minutes." The resulting PPS resin (2) had a sodium concentration of 750 ppm and a melt viscosity of 17 Pa · s in the same manner as in Synthesis Example 1 except that the temperature was raised and held for 30 minutes.

(Synthesis example 3) Manufacture of PPS resin Instead of "After replacing the inside of the autoclave with nitrogen, the temperature was raised to 192 ° C and maintained for 30 minutes", after replacing the inside of the autoclave with nitrogen, up to 150 ° C The resulting PPS resin (3) had a sodium concentration of 1800 ppm and a melt viscosity of 15 Pa · s in the same manner as in Synthesis Example 1 except that the temperature was raised and held for 30 minutes.

(Comparative synthesis example 1) Manufacture of PPS resin Instead of "After the inside of an autoclave was substituted with nitrogen, it heated up to 192 degreeC and hold | maintained for 30 minutes." The PPS resin (4) thus obtained had a sodium concentration of 30 ppm and a melt viscosity of 15 Pa · s, except that the sample was used.

(Comparative Synthesis Example 2) Production of PPS Resin Instead of “After replacing the inside of the autoclave with nitrogen, the temperature was raised to 192 ° C. and kept for 30 minutes”, “After replacing the inside of the autoclave with nitrogen, 130 ° C. The resulting PPS resin (5) had a sodium concentration of 2500 ppm and a melt viscosity of 12 Pa · s, except that the sample was used.

(Examples 1 to 3, Comparative Example 1)
After mixing 30000 parts by mass of PPS resins (1) to (5) obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Example 1 using a tumbler, a twin-screw kneading extruder (TEM) with a nozzle attached to the tip -35B, Toshiba Machine) and melt kneaded at 300 ° C. to obtain a melt.
Next, a stainless steel drum (diameter: 300 mm) that can be rotationally driven is placed at a position 150 cm away from the tip of the nozzle, and pulp paper (manufactured by Nippon Paper Papillia; thickness 30 μm, basis weight 30 g / m ² ) on the outer peripheral surface thereof. , The tensile strength was 37.8 N / 15 mm), and the end of the pulp paper and the drum were fixed with tape. The nozzle is connected to a high voltage power source so as to be positive, a voltage of 10 kV is applied between the nozzle and the stainless steel drum, and the melt is discharged from the nozzle tip (spinning temperature 320 ° C., discharge amount 46.1 parts by mass / min). The polyarylene sulfide fiber was wound around the surface of the pulp paper while cooling with air (tensile speed: 1000 m / min). Various evaluation was performed with respect to the obtained polyarylene sulfide fiber. The evaluation results are shown in Table 1.

  In Comparative Synthesis Example 1, yarn breakage was liable to occur, spinnability deteriorated, and fibers having nanoscale fiber diameters could not be mass-produced stably. On the other hand, Comparative Synthesis Example 2 not only significantly deteriorated the spinnability due to the generation of gas derived from PAS resin, uneven viscosity, and generation of foreign matter, but also stably mass-produces fibers having nanoscale fiber diameters. There wasn't.

Claims (3)

A method for producing a fiber having a diameter of 50 μm or less comprising a polyarylene sulfide resin,
Kneading the polyarylene sulfide resin at a temperature equal to or higher than the melting point to form a melt, and then electrospinning the melt to obtain a fiber;
The polyarylene sulfide resin has a sodium content in the range of 40 to 2000 ppm.   The method for producing a polyarylene sulfide fiber according to claim 1, wherein an applied voltage is in the range of 5 to 70 kV in the melt electrospinning. A fiber made of polyarylene sulfide resin and having a diameter of 50 μm or less,
The polyarylene sulfide resin is characterized in that the polyarylene sulfide resin has a sodium content in the range of 40 to 2000 ppm or less.