JP2016166431A - Polyarylene sulfide resin fiber assembly and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amorphous polyarylene sulfide (PAS) resin fiber assembly in which heat shrinkage can be suppressed, and a method for producing a PAS resin fiber assembly produced using the fiber assembly.SOLUTION: Provided is a method for producing a PAS resin fiber assembly where a dissolved matter obtained by heating and melting a PAS resin and a solvent capable of dissolving the resin and made compatible is discharged to a strand from a resin discharge port, the strand is drawn from an air discharge port installed adjacently to the resin discharge port of a die with air at a temperature higher than the resin melting temperature to obtain refined fiber, the obtained fiber is collected in a collector, the obtained fiber assembly is subjected to annealing treatment in the range from the recrystallization temperature to the melting point, and the solvent is removed from the obtained fiber assembly. Also provided is a PAS resin fiber assembly in which the crystallization degree lies in the range of 30 to 60%, and the dimensional change rate before and after heat treatment at 150°C for 5 min is 30% or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fiber assembly made of an ultrafine polyarylene sulfide resin (hereinafter referred to as a polyarylene sulfide resin fiber assembly) and a method for producing the resin fiber assembly.

As a method for producing a fiber made of a polyarylene sulfide thermoplastic resin, a melt blow method is known (see References 1, 2 and the like). The melt-blowing method is a method in which a molten resin discharged from a resin discharge port at the tip of a nozzle is fiberized by blowing and stretching high-temperature air (Air) instantaneously and immediately after discharge. Since the polyarylene sulfide resin fibers obtained in the spinning process are amorphous, a process of heating the crystallization temperature of the polyarylene sulfide resin, so-called annealing treatment, to promote crystallization is essential.
However, when annealing treatment is performed on amorphous fibers or aggregates thereof, there is a problem in that the fibers are deformed due to heat shrinkage. For this reason, it was difficult to produce a nonwoven fabric or cotton-like fiber aggregate with a small basis weight.

JP 2004-348984 A JP 2002-105834 A

  The problem to be solved by the present invention is an amorphous polyarylene sulfide resin fiber assembly capable of suppressing thermal shrinkage, and a polyarylene sulfide resin fiber assembly produced using the fiber assembly. A manufacturing method is provided.

  As a result of diligent efforts to solve the above problems, the present inventors have solved the present invention by the following means.

That is, in the present invention, a melt obtained by heat-melting the polyarylene sulfide resin (a) and the solvent (b) capable of dissolving the resin (a) with a melt kneading extruder having a die attached to the tip is obtained. Obtaining step 1,
Step 2 for feeding the obtained melt to the die,
Step 3 of discharging a strand from a resin discharge port of a die and obtaining a fine fiber by stretching the strand with air at a temperature higher than a resin melting temperature from an air discharge port installed adjacent to the resin discharge port of the die;
Step 4 of collecting the obtained fiber in a collector,
Step 5 of annealing the obtained fiber assembly within the range from the crystallization temperature to the melting point,
Step 6 for removing the solvent (b) from the obtained fiber assembly,
The present invention relates to a method for producing a polyarylene sulfide resin fiber assembly characterized by comprising:

  The present invention also relates to a polyarylene sulfide resin fiber assembly having a crystallinity of 30 to 60% and a dimensional change rate of 30% or less before and after heat treatment at 150 ° C. for 5 minutes.

  According to the present invention, there is provided an amorphous polyarylene sulfide resin fiber assembly that can suppress thermal shrinkage, and a method for producing a polyarylene sulfide resin fiber assembly that is produced using the fiber assembly. Can be provided.

It is a conceptual diagram of an example of the apparatus which can be used suitably for the manufacturing method of the PAS fiber assembly of this invention. 2 is a cross-sectional view of the die of FIG. It is a conceptual diagram of an example of the apparatus which can be used for the manufacturing method of the PAS fiber assembly of this invention. It is sectional drawing of the die slit for melt blow of FIG. It is an example of marking of the measurement sample of a dimensional change rate.

The method for producing the polyarylene sulfide resin fiber of the present invention includes:
Step 1 for obtaining a melted solution in which the polyarylene sulfide resin (a) and the solvent (b) capable of dissolving the resin (a) are heated and melted with a melt-kneading extruder having a die attached to the tip thereof,
Step 2 for feeding the obtained melt to the die,
Step 3 of discharging a strand from a resin discharge port of a die and obtaining a fine fiber by stretching the strand with air at a temperature higher than a resin melting temperature from an air discharge port installed adjacent to the resin discharge port of the die;
Step 4 of collecting the obtained fiber in a collector,
Step 5 of annealing the obtained fiber assembly within the range from the crystallization temperature to the melting point,
Step 6 for removing the solvent (b) from the obtained fiber assembly,
It is characterized by having.

(Polyarylene sulfide resin)
The polyarylene sulfide resin (PAS resin) preferably 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. )

(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.

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).

The structural site represented by the formula (1) may be included at 30 mol% or less of the total with the structural site represented by the formula (1). 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.

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.

The polyarylene sulfide resin used in the present invention preferably has a melt viscosity (V6) measured at 300 ° C. in the range of 1 to 1000 [Pa · s], and further has a good balance between fluidity and mechanical strength. Therefore, the range of 1 to 100 [Pa · s] is more preferable, and the range of 5 to 50 [Pa · s] is particularly preferable. However, in the present invention, the melt viscosity (V6) is as follows: polyarylene sulfide resin using a flow tester manufactured by Shimadzu Corporation, CFT-500C, 300 ° C., load: 1.96 × 10 ⁶ Pa, L / D = 10/1 The melt viscosity is measured after holding for 6 minutes.

  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) was measured by measuring the shear rate and shear stress using a capillograph at 300 ° C, the ratio of orifice length (L) to orifice diameter (D), and L / D = 40. These are values calculated using the following formula.

[Wherein SR represents a shear rate (second ⁻¹ ), SS represents a shear stress (dyn / 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 range of .02 mole (WO2010 / 058713 pamphlet reference.) Is what is particularly preferably obtained by.

(Solvent that can dissolve polyarylene sulfide resin)
Next, the solvent (b) capable of dissolving the polyarylene sulfide resin (a) is not particularly limited as long as it has a melting point of 100 ° C. or lower and can dissolve the polyarylene sulfide resin. A solvent having a melting point of 100 ° C. or lower and a Hansen solubility parameter (hereinafter, also referred to as SP value) in the range of 24.0 to 48.0 [MPa ^1/2 ] represents the polyarylene sulfide resin (a). Since it can be made compatible at a molecular level, it is mentioned as a preferable solvent. However, the Hansen solubility parameter used in the present invention is a parameter used for evaluating the affinity between the solvent and the polyarylene sulfide resin, and is well known to those skilled in the art as a method for defining the solvent solubility parameter. For example, “INDUSTRIAL SOLVENTSHANDBOOK” (pp. 35-68, published by Marcel Dekker, Inc., 1996) and “HANSEN SOLUBILITY PARAMETERS: A USER'S HANDBOOK” (pp. 1-41, CRC Press, 1919, CRC Press). (Pp. 22-29, Black Academic & Professional, 1996). In the present invention, as the Hansen solubility parameter, the Hansen solubility parameter may be calculated based on the chemical structure of the solvent, or a value described in the above-mentioned reference may be used. When calculating the Hansen solubility parameter based on the chemical structure of the solvent, it can be calculated by inputting the structural formula of the solvent into the HSP software. Specifically, it can be obtained from a software developed by Charles Hansen et al. (Software name: Hansen Solubility Parameter in Practice (HSPIP) Version 3.0.38). The calculation is performed at a solvent temperature of 25 ° C.

  Specific examples of the solvent (b) include benzophenone, diphenyl ether, diphenyl sulfide, 4,4′-dibromobiphenyl, 1-phenylnaphthalene, 2,5-diphenyl-1,3,4-oxadiazole, 2 , 5-diphenyloxazole, triphenylmethanol, N, N-diphenylformamide, benzyl, anthracene, 4-benzoylbiphenyl, dibenzoylmethane, 2-biphenylcarboxylic acid, dibenzothiophene, pentachlorophenol, 1-benzyl-2-pyrrolidione 9-fluorenone, 2-benzoylnaphthalene, 1-bromonaphthalene, 1,3-diphenoxybenzene, fluorene, 1-phenyl-2-pyrrolidinone, 1-methoxynaphthalene, 1-ethoxynaphthalene, 1,3-diphenyl Seton, 1,4-dibenzoylptane, phenanthrene, 4-benzoylbiphenyl, 1,1-diphenylacetone, 0,0'-biphenol, 2,6-diphenylphenol, triphenylene, 2-phenylphenol, thianthrene, 3-phenoxy Benzyl alcohol, 4-phenylphenol, 9,10-dichloroanthracene, triphenylmethane, 4,4′-dimethoxybenzophenone, 9,10-diphenylanthracene, fluoranthene, diphenylphthalate, diphenyl carbonate, 2,6-dimethoxynaphthalene, 2,7-dimethoxynaphthalene, 4-bromodiphenyl ether, pyrene, 9,9'-bifluorene, 4,4'-isopropylidene-diphenol, epsilon-caprolactam, N-cyclohe Sil-2-pyrrolidone, diphenyl isophthalate and diphenyl chromatography terpolymers phthalate, one or more solvents selected from the group consisting of 1-chloronaphthalene and the like.

  Among these, the boiling point is as high as 255 ° C. or higher, the SP value is close to that of the polyarylene sulfide resin (SP value 42.2), and the compatibility is excellent, which is preferable. For example, benzophenone (SP value 41.2), diphenyl ether (SP value 40.0), diphenyl sulfide (SP value 40.2), 1,3-diphenylacetone (SP value 42.4), 4-bromodiphenyl ether (SP One or more selected from the group consisting of: value 44.7), 4-bromobiphenyl (SP value 42.4), 2-benzoylnaphthalene (SP value 45.1), 2-phenylphenol (SP value 46.8) It is preferable that it is a solvent. In particular, benzophenone, 1,3-diphenylacetone, 4-bromobiphenyl, 2-benzoylnaphthalene, and 2-phenylphenol are preferable because they are solid at room temperature.

  Furthermore, in addition to the polyarylene sulfide resin (a) and the solvent (b), other additives such as a heat stabilizer, an oxidation stabilizer, a weather stabilizer, and an ultraviolet absorber are added within the range not impairing the characteristics of the present invention. Further, a lubricant, a pigment, a dye, organic or inorganic fine particles, a filler, a nucleating agent, and the like can be blended.

(Process 1)
Step 1 is a step of obtaining a dissolved product in which the polyarylene sulfide resin (a) and the solvent (b) are dissolved by heating. Here, the polyarylene sulfide resin (a) and the solvent (b) may be heated and dissolved in a non-oxidizing atmosphere. Note that the non-oxidizing atmosphere is an atmosphere having a gas phase oxygen concentration of 5% by volume or less, preferably 2% by volume or less, more preferably an oxygen-free atmosphere such as nitrogen, helium, argon, or the like. It means that. Further, the temperature for melting by heating is in the range of the melting point of the solvent (b) or higher, preferably in the temperature range of the melting point + 10 ° C. or more, more preferably in the temperature range of melting point + 10 ° C. to melting point + 100 ° C., more preferably melting point + 20 Although it is the temperature range of ° C to melting point + 50 ° C, a specific example is preferably in the range of 200 to 350 [° C].

  Furthermore, the blending ratio of the polyarylene sulfide resin (a) and the solvent (b) is based on a total of 100 parts by mass of the polyarylene sulfide resin (a) and the solvent (b). It is preferable that a) is in the range of 50 to 95 parts by mass, and the solvent (b) is in the range of 50 to 5 parts by mass, and the polyarylene sulfide resin (a) is in the range of 70 to 95 parts by mass. And it is more preferable that the said solvent (b) is the range of 30-5 mass parts. If the polyarylene sulfide resin (a) is 50 parts by mass or more, the fluid viscosity is preferably uniform, and more preferably 70 parts by mass or more from the viewpoint of productivity, while 95 parts by mass or less, more preferably The amount of 90 parts by mass or less is preferable because it tends to be excellent in suppressing thermal shrinkage in the heat treatment step.

  The melt-kneading conditions are not particularly limited as long as the effects of the present invention are not impaired. For example, melt-kneading is performed under conditions where the discharge amount of the resin component is in the range of 0.6 to 30 (g / min). Is preferred.

  When an additive is added as an optional component to the resin (a) and the solvent (b), the mixture is preliminarily uniformly mixed beforehand with a tumbler or Henschel mixer, and then a melt-kneading extruder such as a twin-screw kneading extruder. It is preferable to add to the melt and knead.

(Process 2-3)
The melted product of the resin (a) and the solvent (b) melted by the melt-kneading extruder is fed into a die having a resin discharge port and further discharged from the die.

  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. The cross-sectional shape of the discharge port can be selected as appropriate according to the cross-sectional shape.

  The inner diameter of the resin discharge port (nozzle hole inner diameter) is not particularly limited as long as the effects of the present invention are not impaired, but from the viewpoint of fiber miniaturization and discharge stability, a range of 0.3 to 1.0 mmφ is preferable. The range of 0.4-0 and 9 mmφ is more preferable.

  The die temperature is preferably in the same range as the temperature at which the resin is melt-kneaded in the melt-kneading extruder, and specifically, it is preferably +10 to 100 ° C. from the melting temperature of the resin, and further the melting point of the resin More preferably, the temperature is +10 to 50 ° C. If it is melting | fusing point +10 degreeC or more, since solidification of resin is prevented and sufficient extending | stretching advances, it is preferable. On the other hand, if it is melting | fusing point +50 degrees C or less, since gelatinization and oxidation of resin can be prevented, it is preferable.

  The discharge amount of the melt from the resin discharge port is not particularly limited as long as the effect of the present invention is not impaired, but is preferably in the range of 0.5 to 30.0 g / min / hole, and more preferably 0.7 to 20 More preferably, the range is 0.0 g / min / pore. If it is 0.5 g / min / hole or more, it is preferable because the stability of ejection can be ensured. On the other hand, if it is 30.0 g / min / hole or less, it is preferable from the viewpoint of refinement of the obtained fiber.

  The discharge rate (V1) of the melt from the resin discharge port is not particularly limited as long as the effect of the present invention is not impaired, but is preferably in the range of 0.05 to 2.80 m / s, and more preferably 0.07 to More preferably, the range is 1.90 m / s.

  At the same time as discharging the melt from the resin discharge port, the molten polymer discharged in a strand shape is stretched by air at a temperature higher than the die temperature discharged from the air discharge port provided adjacent to the resin discharge port. A fine fiber is obtained.

  The shape and the diameter of the air discharge port are not particularly limited as long as the effects of the present invention are not impaired. For example, in the case of one hole, the diameter is preferably in the range of 1.0 to 5.0 mmφ. More preferably, it is in the range of 2.0 to 4.0 mmφ. 2.0 mmφ or more is preferable from the viewpoint of airflow stabilization, and 4.0 mmφ or less is preferable from the viewpoint of suppressing a decrease in air temperature and air speed. The shape of the air discharge port may be a slit type or a plurality of holes in addition to a single hole.

  The temperature of the air when discharged from the air discharge port is not particularly limited as long as the effects of the present invention are not impaired, but it is higher than the resin melting temperature, preferably in the range of +10 to 100 ° C. higher than the resin melting temperature, The temperature is preferably in the range of +10 to 50 ° C. higher than the resin melting temperature. If the temperature range is higher than the resin melting temperature by 10 ° C or higher, solidification of the molten polymer can be prevented. On the other hand, if the temperature range is 50 ° C or higher than the resin melting temperature, the resin gelation or This is preferable because oxidation can be prevented.

  The speed at which air is discharged from the air discharge port (air discharge speed (V2)) is not particularly limited as long as the effect of the present invention is not impaired, but is preferably in the range of 300 to 1200 mm / s, and more preferably 500 to More preferably, it is in the range of 1000 mm / s. If it is 500 mm / s or more, it is preferable because the fiber becomes finer. On the other hand, if it is 1000 mm / s or less, it is preferable from the viewpoint of stabilizing the airflow formed by air.

  The air component uses air from the viewpoint of productivity, but is not particularly limited as long as the effects of the present invention are not impaired. From the viewpoint of blocking oxygen and preventing gelation and oxidation of the molten polymer, nitrogen air or the like is used. Inert air may be used.

The speed ratio (V2 / V1) of the air speed (V2) at the air discharge port to the strand speed (V1) discharged from the resin discharge port is not particularly limited as long as the effect of the present invention is not impaired. From the viewpoint of easily producing fibers having a fiber diameter of a micron unit, it is preferably in the range of 1 × 10 ^{2 to} 150 × 10 ² , and more preferably in the range of 4 × 10 ^{2 to} 120 × 10 ^2. More preferred.

  The strand discharge direction at the resin discharge port and the air discharge direction at the air discharge port do not need to be particularly parallel and are not limited, but are substantially parallel from the viewpoint of stable resin discharge during spinning and fiber refinement. It is preferable. The angle between the discharge direction of the strand at the resin discharge port and the discharge direction of the air at the air discharge port is set by the center line of the discharge direction of the nozzle provided on the die and the center line of the discharge direction of the air discharge hole. It is preferable to design and manufacture at an angle. Note that “substantially parallel” refers to the angle formed by the strand discharge direction (center line of the nozzle discharge direction) at the resin discharge port and the air discharge direction (center line of the air discharge hole discharge direction) at the air discharge port. Although it is preferably 0 °, it means that it may be within a range of −20 ° to + 20 °.

  The distance between the air discharge port 5 and the resin discharge port is in the range of 2 to 20 mm, preferably in the range of 5 to 10 mm.

(Process 4)
The obtained polyarylene sulfide resin fibers are collected in the collector part and obtained as a polyarylene sulfide resin fiber aggregate.

  The distance between the resin discharge port and the collector portion is not particularly limited as long as the effects of the present invention are not impaired, but is preferably in the range of 30 to 300 cm, and more preferably in the range of 100 to 200 cm. If it is 30 cm or more, it becomes possible to maintain the high temperature state of the molten resin, and it is preferable for reducing the diameter because it takes a long time to receive the stretching effect by air. It is preferable because fiber collection is easy.

  The collector is not particularly limited as long as the effects of the present invention are not impaired. However, it is preferable that the collector is an apparatus that can continuously collect with a roll.

  In addition, the production method of the present invention is characterized in that the polyarylene sulfide resin and the solvent are rapidly cooled from the state in which they are compatibilized, so that a lamellar structure is easily formed as compared with the case where the polyarylene sulfide resin (a) alone is quenched. . Therefore, even if it is a polyarylene sulfide resin fiber aggregate before annealing treatment, it can be obtained in a higher crystallinity state. For this reason, the dimensional change (heat shrinkage) rate is, for example, in the range of 30% or less, preferably in the range of 15% or less, even when the annealing treatment is performed, even though the fiber is in the range of 50 nm to 10 μm. Can be suppressed. Therefore, when performing the annealing treatment, it is not necessary to fix the fiber or the fiber assembly itself by applying tension (tension), and it is possible to create a non-woven fabric having a small basis weight or a cotton-like fiber assembly.

  Here, the degree of crystallinity of the polyarylene sulfide resin fiber aggregate before annealing, which is obtained through Step 4 of the production method of the present invention, is not particularly limited, but is preferably in the range of 30 to 60%. More preferably, it is 40 to 60% of range.

(Steps 5-6)
Subsequently, the polyarylene sulfide resin fiber assembly obtained in Step 4 is annealed within the range of the melting point from the crystallization temperature of the polyarylene sulfide resin, and the solvent (b) is removed from the fiber assembly. Step 6 of removing is performed.

  The annealing treatment is performed, for example, so that the fiber aggregate is in the range from the crystallization temperature of the polyarylene sulfide resin to be used to the melting point or less, preferably in the intermediate temperature range between the crystallization temperature and the melting point. As a specific method, a hot hot air is applied to the fiber assembly at a wind speed of preferably 1 to 5 m / second for 20 to 180 seconds, a method of irradiating infrared rays, or heating to a predetermined temperature 2 It can be carried out by a method of heating along a pair of rolls without applying pressure, a method of heating at a predetermined temperature by sandwiching both ends of the fiber assembly with a pin tenter, and the like. The crystal state is further stabilized by the annealing treatment.

  The annealing process in step 5 and the solvent removal process in step 6 may be performed in this order or simultaneously.

  The crystallinity of the polyarylene sulfide resin fiber aggregate after the annealing treatment is not particularly limited, but is preferably in the range of 31% to 61%, and more preferably in the range of 36% to 61%. It is more preferable to set it in a range of 41% to 61%.

  As a method for removing the solvent (b) from the obtained fiber aggregate, a known solvent drying method can be employed, for example, a washing solvent such as warm air drying, infrared drying, vacuum drying, etc. is evaporated. Examples thereof include a method, a method of performing evaporation together with evaporation such as suction drying and vapor drying, and a drying method using liquid removal such as air knife draining, spin drying and squeeze roll drying. It is preferable to use these in combination since the solvent can be efficiently removed.

  For example, the fiber assembly is fed with a roller made of a water-absorbing material such as a sponge and sucked and removed, and then the fiber assembly is blown with hot air or irradiated with infrared rays to A method in which the aggregate is heated to a boiling point or higher, or the solvent is boiled by reducing the vapor pressure of the solvent to evaporate the solvent from the fiber aggregate, and the solvent (b ) Is replaced with a solvent (c) which is a solvent in which the polyarylene sulfide resin does not dissolve or swell and is compatible with the solvent (b), and the solvent (c) is dried. Examples of such a solvent (c) include aliphatic alcohols such as acetone, methanol and ethanol, hydrocarbons such as hexane and heptane, chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride, and methyl ethyl ketone. it can.

  It is preferable to make the content of the solvent remaining in the fiber assembly 0.01% by mass or less by the above solvent removal treatment (the mass of the fiber assembly after drying is 100% by mass), and the detection limit More preferably, it is as follows. Insufficient drying and a large amount of the solvent remaining in the fiber assembly is not preferable because the operability deteriorates after the secondary processing of the fiber assembly.

  Furthermore, the polyarylene sulfide resin fiber assembly obtained through Steps 1 to 6 is further subjected to known surface treatments such as crosslinking treatment, hydrophilization treatment, corona treatment machine, plasma treatment machine, ozone treatment machine, flame treatment machine and the like. It is also possible to apply.

  Since the polyarylene sulfide resin fiber assembly of the present invention obtained by the above production method is easy to control the fiber diameter from the submicron range to the micron order range, the fiber diameter (diameter) of the obtained fiber is: Although not particularly limited, it is preferably in the range of 10 μm or less, more preferably in the range of 5 μm or less, and more preferably in the range of 1 μm or less. The lower limit of the fiber diameter is not particularly limited, but is preferably in the range of 50 nm or more, more preferably in the range of 100 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.

The basis weight of the polyarylene sulfide resin fiber aggregate of the present invention obtained by the above production method is not particularly limited. For example, in the range of 10 to 500 g / m ² , the basis weight according to the purpose (10 cm × according to JIS L1085) The value measured as 10 cm). In particular, the production method of the present invention does not need to apply tension to the fiber or fiber assembly itself by annealing treatment, and therefore has excellent selectivity in the spinning process, and has a low basis weight such as 10 to 100 g / m ^2. A cotton-like fiber assembly can be produced.

  Hereinafter, although an example of the apparatus used by this invention is demonstrated, this invention is not limited to the said apparatus. The apparatus used in the present invention is a melt-kneading extruder, a hopper for supplying polyarylene sulfide resin to the extruder, a die provided at the tip of the extruder, and a resin discharge port attached to the tip of the die. A nozzle, an air discharge port provided adjacent to the nozzle, and a collector roller provided at a predetermined distance from the resin discharge port. Air heated by a heater is supplied to the die from an air supply device through an air transport pipe.

  The die consists of an upper die plate and a lower die plate having a heater inside. By combining the upper die plate and the lower die plate, an air chamber for storing heated air is formed inside the die. Further, the air transport pipe is connected to the air chamber, and heated air is supplied. On the other hand, the melted material melted by the extruder is accumulated in the resin chamber through the introduction port, heated by the heater so as to maintain the molten state, and then discharged from the resin discharge port in a strand shape through the nozzle.

Furthermore, the polyarylene sulfide resin fibers collected by the collector roller are accumulated on the collection surface.

  Moreover, although the amorphous polyarylene sulfide resin fiber aggregate obtained by the production method of the present invention is made into ultrafine fibers in an amorphous state, it can suppress heat shrinkage due to annealing treatment. Therefore, when performing the annealing treatment, it is not always necessary to fix the fiber itself by applying tension (tension), and a nonwoven fabric with a small basis weight or a cotton-like fiber aggregate can be produced.

  Since the polyarylene sulfide resin fiber assembly of the present invention also has various performances such as heat resistance and dimensional stability inherent to the polyarylene sulfide resin, for example, connectors, printed circuit boards, sealing molded products, etc. Textiles used in the fields of automotive parts such as electric / 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 as 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 assembly 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.

Example 1
Using the apparatus described in FIGS. 1 and 2, polyphenylene sulfide resin DIC. PPS (V6 melt viscosity at 300 ° C., 10 Pa · s, non-NT index 1.1) 8000 g and benzophenone (DPK solvent) 2000 g were mixed and then melt kneaded with an extruder (temperature 300 ° C.) to obtain a die (resin chamber (Set temperature 300 ° C.), and then strand from the resin discharge port at the tip of the 0.71 mm diameter nozzle provided on the die at a resin discharge rate of 1.5 g / min and a resin discharge speed (V1) of 0.14 m / sec. The molten resin was discharged in the form of a strand, and at the same time, air was discharged from the air discharge port provided in the die at an air temperature of 360 ° C., an air flow rate of 75 liters / min, and an air flow rate (V2) of 830 m / sec. The resin was stretched. The angle formed by the resin discharge port-air discharge port 5 mm, the resin discharge port-collector interval 150 cm, the center line (ψ4a) of the discharge direction of the nozzle 4 and the center line (ψ5) of the discharge direction of the air discharge hole 5 is 0 degree. The molten resin was stretched with air under the conditions (substantially parallel) to obtain a PPS resin fiber assembly (α-1).

  Subsequently, the PPS resin fiber assembly (α-1) was heated to 180 ° C. using a vacuum dryer and held for 5 minutes. Then, the sample was taken out from the vacuum dryer and cooled to room temperature (23 ° C.) to obtain a PPS resin fiber assembly (β-1). Table 1 shows the results of various measurements performed on the obtained PPS resin fiber aggregates (α-1) and (β-1).

(Examples 2 to 6)
PPS resin fiber aggregates (α-2) to (α-6), PPS resin fiber aggregates (α), except that the composition ratios and production conditions described in Tables 1 and 2 were changed to production conditions. β-2) to (β-6) were obtained. Tables 1 and 2 show the results of various measurements performed on the obtained PPS resin fiber assemblies (α-2) to (α-6) and (β-2) to (β-6).

(Reference Example 1)
* In order to investigate the DPK solvent removal effect by the acetone solvent, a PPS resin fiber assembly was prepared without performing the heating step (annealing step).

A PPS resin fiber aggregate (α-7) was obtained in the same manner as in the step of obtaining the PPS resin fiber aggregate (α-1) of Example 1, except that the composition ratios and production conditions described in Tables 1 and 2 were changed. )
Subsequently, the PPS resin fiber aggregate (α-7) was immersed in an acetone solvent for 24 hours to remove the DPK solvent, and then allowed to stand at room temperature for 24 hours to obtain a PPS resin fiber aggregate (β-7). Table 2 shows the results of various measurements performed on the obtained PPS resin fiber aggregates (α-7) and (β-7).

(Comparative Example 1)
A PPS resin fiber assembly (α-8) and a PPS resin fiber assembly (β-8) were obtained in the same manner as in Example 1 except that the composition and production conditions described in Table 2 were used. Table 2 shows the results of various measurements performed on the obtained PPS resin fiber aggregates (α-8) and (β-8).

However, each measured value in the above Examples and Comparative Examples was measured by the following method.

(Measurement of crystallinity / crystallization temperature)
For the PPS resin fiber aggregates (α-1) to (α-8), the crystallinity was measured by the following method. That is, by using a differential scanning calorimeter “DSC8500” manufactured by PerkinElmer Co., Ltd., 5 mg of PPS resin fiber aggregates (α-1) to (α-8) as a sample from 40 ° C. at a heating rate of 20 ° C./min. The temperature was raised to 350 ° C., and the calorific value (ΔH _c , unit is J / g) near the crystallization temperature of the polyarylene sulfide resin and the endothermic amount (ΔH _f , unit is J / g) near the melting point were measured. did. Based on the following formula, the degree of crystallinity X _c (%) was calculated from the obtained heat quantity (J / g). However,

However, ΔH ⁰ _f represents the heat of fusion of the complete crystal and was calculated as “80 J / g” which is typically used (from Brady, DG Journal of Applied Polymer Science 1976, 20, pp2541-2551).

(Dimensional change rate during heat shrinkage of PPS resin fiber assembly)
For the PPS resin fiber assemblies (α-1) to (α-8), a fiber assembly adjusted to a basis weight of 100 g / m ² was hot-pressed at 80 ° C. in order to produce a 100 mm square nonwoven fabric sample. . The measurement section was marked on the obtained sample, and arbitrary three locations were measured (FIG. 5). Next, the sample was heat-treated in an oven at 150 ° C. for 5 minutes, returned to room temperature, and then measured again for the measurement interval. Based on the obtained measured value, the average value was calculated from the dimensional change rate ΔL (%) during heat shrinkage by the following formula.

L ₀ : Length of measurement section before heat treatment (mm)
L: Length of measurement section after heat treatment (mm)

(Measurement of DPK residual ratio in PPS resin fiber assembly)
The residual ratio R (wt%) of DPK in the PPS resin fiber aggregates (β-1) to (β-8) was measured by the following method. That is, using a differential thermal balance (differential thermal balance “TG-8120” manufactured by Rigaku Corporation), PPS resin fiber aggregates (β-1) to (β-8) were weighed as samples (initial weight of PPS fiber aggregates). ), The temperature was raised from 23 ° C. to 480 ° C. at a temperature raising rate of 10 ° C./min, and again weighed (weight after heating of the PPS fiber assembly). A value obtained by subtracting “weight after heating of PPS fiber assembly” from “initial weight of PPS fiber assembly” was defined as “weight reduction amount of sample fiber”. It measured about each sample fiber of Examples 1-5 and the comparative example 1, and calculated DPK residual rate R (wt%) from the following formula | equation.

However,
ΔW _n : Weight reduction amount of each sample (PPS fiber assembly) of Examples 1 to 5 ΔW ₀ : Weight reduction amount of sample of Comparative Example 1 (PPS fiber assembly) W _n : Each sample of Examples 1 to 5 Initial weight of (PPS fiber assembly)

(Average 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).

  As for the fiber diameter, any 20 non-overlapping spots are selected at a magnification (1000 times) at which the fiber diameter can be confirmed, and further, any 5 fibers are extracted at the 20 places, and a predetermined magnification ( The fiber diameter was confirmed at 3000 times. The number average of the obtained fiber diameters of the above 100 points (20 points × 5 points) was calculated and used as the average fiber diameter of the sample.

* 1 Measured value at the discharge hole

* 1 Measured value at discharge hole * 2 Cannot be measured due to fiber aggregation

1 Melting and kneading extruder
2 Hopper
3 die
3a Upper die plate
3b Lower die plate
4a Resin outlet
4 nozzles
5 Air outlet
6 Collector roller
7 Air transport pipe
8 Air supply device
9 Heater
10 Heater
11 Air chamber
12 Introduction port 13 Resin chamber 14 Fiber collection surface ψ4a Center line in the discharge direction of the nozzle 4
ψ5 Center line 21 in the discharge direction of the air discharge hole 5 Melt blow die (high temperature air discharge nozzle part)
22 Melt blow die (molten resin discharge nozzle)
101 Melt kneading extruder
102 hopper
123 Die slit
110 Resin outlet (resin outlet slit)
111 Air discharge port (Air discharge slit)
106 Collector roller
107 Pneumatic transport pipe
108 Air supply device
109 heater
112 Introduction port 114 Fiber collection surface ψ110 Center line in the discharge direction of the resin discharge slit
ψ111 Center line in the discharge direction of the air discharge slit

Claims (8)

Step 1 for obtaining a melted solution in which the polyarylene sulfide resin (a) and the solvent (b) capable of dissolving the resin (a) are heated and melted with a melt-kneading extruder having a die attached to the tip thereof,
Step 2 for feeding the obtained melt to the die,
Step 3 of discharging a strand from a resin discharge port of a die and obtaining a fine fiber by stretching the strand with air at a temperature higher than a resin melting temperature from an air discharge port installed adjacent to the resin discharge port of the die;
Step 4 of collecting the obtained fiber in a collector,
Step 5 of annealing the obtained fiber assembly within the range from the crystallization temperature to the melting point,
Step 6 for removing the solvent (b) from the obtained fiber assembly,
A process for producing a polyarylene sulfide resin fiber assembly characterized by comprising:   The ratio of the resin (a) and the solvent (b) in the lysate is in the range of 50 to 95 parts by mass of the resin (a) and in the range of 5 to 50 parts by mass of the solvent (b). The manufacturing method of the polyarylene sulfide resin fiber assembly of Claim 1 or 2.   The method for producing a polyarylene sulfide resin fiber assembly according to claim 1 or 2, wherein the solvent (b) is at least one solvent selected from the group consisting of benzophenone, diphenyl ether, diphenyl sulfide and 1,3-diphenylacetone. .   The method for producing a polyarylene sulfide resin fiber assembly according to any one of claims 1 to 3, wherein a dimensional change rate of the polyarylene sulfide resin fiber assembly before and after the step 5 is 30% or less.   The method for producing a polyarylene sulfide resin fiber assembly according to any one of claims 1 to 4, wherein the degree of crystallinity of the polyarylene sulfide resin fiber assembly before the step 5 is in the range of 30 to 60%.   The method for producing a polyarylene sulfide resin fiber assembly according to any one of claims 1 to 5, wherein an average fiber diameter of the thermoplastic resin fibers is in a range of 50 [nm] to 10 [[mu] m].   A polyarylene sulfide resin fiber assembly having a crystallinity of 30 to 60% and a dimensional change rate of 30% or less before and after heat treatment at 150 ° C. for 5 minutes.   The polyarylene sulfide resin fiber assembly according to claim 7, wherein the average fiber diameter is in the range of 50 [nm] to 10 [[mu] m].