JP2014152407A - Method for producing polyphenylene sulfide fiber, and nonwoven cloth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a PPS short fiber in which cotton blending step upon filter cloth preparation is simplified, and the improvement of dust detachability, the improvement of dust collection efficiency and the reduction of pressure loss are made possible.SOLUTION: Provided is a method for producing a polyphenylene sulfide fiber in which at least two or more kinds of fibers with different fiber sizes are simultaneously spun and combined. The single fiber fineness lies in the range of 0.5 to 15 dtex, and a difference in the single fiber fineness is controlled to 0.5 to 10 dtex. A nonwoven cloth and a filter cloth can be produced using the obtained polyphenylene sulfide fiber.

Description

  The present invention relates to a method for producing a polyphenylene sulfide fiber that does not require a blending process when producing the nonwoven fabric, and a nonwoven fabric comprising the polyphenylene sulfide fiber.

  Polyphenylene sulfide (hereinafter abbreviated as PPS) resin has properties suitable as engineering plastics such as excellent heat resistance, barrier properties, chemical resistance, electrical insulation properties and heat and moisture resistance, and injection. It is used for various electrical and electronic parts, machine parts and automobile parts, films, fibers, etc. mainly for molding and extrusion molding. For example, PPS resin materials are widely used for filter cloths used in various industrial filters such as bag filters for collecting waste gas dust. Such a filter cloth is obtained by laminating a fiber web made of PPS short fibers on a base fabric made from spun yarns of PPS short fibers and needle punching, collecting dust in waste gas, and collecting the dust. It is used to exhaust waste gas that does not contain, but it is important to keep the clogging free for a long period of time, and it is always desired to extend the filter cloth performance. .

  In order to suppress the clogging of the filter cloth and to prolong the life of the filter cloth performance, it is effective to detach the attached dust from the filter cloth efficiently. For example, if the filter cloth is clogged in the bag filter, the exhaust gas cannot be exhausted from the incineration facility. Therefore, the incineration facility must be stopped and the filter cloth must be replaced. That is, if the dust is efficiently removed before the filter cloth is clogged, the life of the filter cloth can be extended, and the incineration facility can be operated continuously for a long time.

  In a bag filter, a pulse jet method is often employed as a method for efficiently separating dust adhering to a filter cloth (see Patent Documents 1 and 2). With the pulse jet method, before the dust attached to the surface of the filter cloth accumulates, the filter cloth is vibrated by periodically blowing a high-speed air flow onto the filter cloth, and the dust attached to the surface of the filter cloth is removed. It is a method. Although such a pulse jet method enables dust to be removed, naturally, in this method, a high-speed air flow applied as an external force tends to decrease the mechanical strength of the filter cloth with time. This is because, when an external force is applied periodically, if the mechanical strength of the filter cloth and the dimensional stability of the filter cloth are insufficient, the filter cloth breaks and cannot function as a bag filter.

  On the other hand, environmental regulations are becoming more and more strict, especially in the United States, the regulations on particulate matter floating in the air that are particularly small (PM2.5 regulations) But it may apply. In response to such a flow, there is a demand for an excellent filter having higher dust collection efficiency and less clogging.

  As a countermeasure, a filter cloth in which PPS fibers having a single fiber fineness of 1.8 d (2.0 dtex) or less are arranged on a fiber web on the air inflow side has been proposed (see Patent Document 3). This proposal certainly has the problem that although the dust separation performance and dust collection efficiency tend to improve, the pressure loss due to clogging of the filter cloth is large.

  In addition, a filter cloth including at least two layers of fiber webs and including 50 mass% or more of PPS fibers with a fiber diameter of 15 μm or less (single fiber fineness of 2.2 dtex or less) on the air inflow side is proposed. (See Patent Document 4). In this proposal, by regulating the fiber weight of 15 μm or less, a certain effect can be obtained in terms of dust separation performance, dust collection efficiency, and pressure loss due to clogging of the filter cloth.

  However, in order to blend PPS fibers having a fiber diameter of 15 μm or less, a blending process is required at the time of making the filter cloth, and when the blended cotton is not uniform, dust releasability, dust collection efficiency and pressure loss There is a concern that the effect will be affected. Therefore, this blending process is a process that has a great influence on the filter cloth performance, and more uniform blending is required. However, the existing methods are still insufficient.

Japanese Patent Laid-Open No. 08-103617 JP 09-248413 A Japanese Patent Laid-Open No. 10-165729 WO2004 / 087293

  Then, the objective of this invention is providing the manufacturing method of the polyphenylene sulfide fiber which can aim at simplification of the blending process at the time of filter cloth preparation especially.

  The present invention is to solve the above problems, and the method for producing polyphenylene sulfide fibers of the present invention is a method for producing polyphenylene sulfide fibers in which at least two types of fibers having different single fiber fineness are simultaneously spun and mixed. It is.

  According to the preferable aspect of the manufacturing method of the polyphenylene sulfide fiber of this invention, the said single fiber fineness is the range of 0.5-15 dtex, It is making the difference of a single fiber fineness into 0.5-10 dtex.

  In this invention, a nonwoven fabric can be manufactured from the polyphenylene sulfide fiber obtained with the manufacturing method of said polyphenylene sulfide fiber, and a filter cloth can be manufactured using this nonwoven fabric.

  According to the present invention, a method for producing polyphenylene sulfide fibers that can simplify the blending process at the time of filter cloth creation is provided.Furthermore, by homogenization of the blended fibers by spinning blending, dust releasability improvement, dust collection efficiency improvement, A method for producing polyphenylene sulfide fiber capable of reducing pressure loss is provided.

FIG. 1 is an exploded cross-sectional view of a filter material (filter cloth) using a nonwoven fabric made of polyphenylene sulfide fiber obtained in the present invention. FIG. 2 is a schematic side view of an atmospheric dust collection efficiency measuring apparatus using a filter material (filter cloth) made of polyphenylene sulfide fiber obtained by the present invention. FIG. 3 is a schematic side view of a pressure loss measuring apparatus after dust removal using a filter material (filter cloth) made of polyphenylene sulfide fiber obtained in the present invention.

  The method for producing polyphenylene sulfide fibers of the present invention is a method for producing polyphenylene sulfide fibers in which at least two types of fibers having different fiber diameters are simultaneously spun and mixed.

  The polyphenylene sulfide (PPS) resin used in the present invention means a polymer containing a phenylene sulfide unit such as a p-phenylene sulfide unit or an m-phenylene sulfide unit represented by the following structural formula (I) as a repeating unit. To do.

  The PPS resin may be a homopolymer or a copolymer having both p-phenylene sulfide units and m-phenylene sulfide units, and may be copolymerized with other aromatic sulfides as long as the effects of the present invention are not impaired. It may be a combination or a mixture.

  The PPS resin preferably has a weight average molecular weight of 30,000 to 90,000. When melt spinning is performed using a PPS resin having a weight average molecular weight of less than 30,000, the spinning tension may be low and yarn breakage may occur frequently during spinning, and if a PPS resin having a weight average molecular weight exceeding 90000 is used, The viscosity at that time is too high, and the spinning equipment must have a special high pressure resistance specification, which is disadvantageous because the equipment costs are high. A more preferred weight average molecular weight is 40,000 to 70,000.

  Examples of commercially available PPS resins used in the present invention include “Torelina” (registered trademark) manufactured by Toray Industries, Inc. and “Fortron” (registered trademark) manufactured by Polyplastics Co., Ltd.

  Next, a method for producing the PPS fiber of the present invention will be described.

  Preferably, a PPS resin having a weight average molecular weight of 30,000 to 90,000 as described above is melted and simultaneously spun from 2 to 100 spout golds, and at least two types of fibers having different single fiber fineness are spun simultaneously. At this time, the spinning is performed so that the ratios of the different finenesses are different from each other, preferably 5% or more, more preferably 10% or more of the total number of spindles that are spun simultaneously.

  The ratio of different fineness here refers to the presence ratio of fibers having the lowest mixing ratio among two or more kinds of fibers having different finenesses. For example, in the case of a mixed fiber in which 3.3T is 80% and 6.6T is 20%, the ratio of the different fineness is 20%. Further, when 3.3T is 50%, 6.6T is 40%, and 7.8T is 10%, the ratio of the different fineness is 10%. By setting the ratio of the different finenesses to 5% or more, the fiber mixture obtained is good and preferable. If it is less than 5%, the resulting mixed fiber is unfavorable.

  In order to obtain two or more different single fiber finenesses, for example, a base having a different number of base holes may be attached, or the amount of polymer discharged to be spun may be changed to adjust the target fineness.

  When attaching a base having a different number of base holes, by making the polymer discharge amount constant for all the bases, the discharge amount per single hole of the base can be adjusted, and the fineness can be adjusted. When changing the polymer discharge amount to be spun, it can be obtained by adjusting the discharge amount per single hole to a predetermined fineness.

  When spinning, it is preferable to distribute and attach evenly throughout the spinning machine. For example, in the case of two kinds of different fineness blends, when the fibers are mixed at a rate of 50%, the bases having different fibers are attached alternately. When the fiber mixing ratio on one side is 66% (A) and the fiber mixing ratio on the other side is 33% (B), one (B) is placed beside the two (A) bases mounted side by side. Install side by side and repeat. In addition, for example, in the case of three kinds of different fineness mixed fibers, when mixed at a rate of 33% each, the obtained fibers are attached side by side with different bases (A), (B), (C), and this is repeated. . When a base having different fibers is fixed to one place of a spinning machine to perform spinning, the mixed state in spinning becomes worse and the uniformity tends to be inferior.

  As described above, when spinning different fibers, it is necessary to simultaneously spin different single fiber finenesses, and the difference between the different single fiber finenesses is preferably 0.5 dtex or more, more preferably 1.0 dtex. That's it. When the single fiber fineness difference is 0.5 dtex or less, there is a tendency that the effects of mixed fiber, such as improvement of dust releasability, improvement of dust collection efficiency, and reduction of pressure loss, are reduced. Moreover, as an upper limit of the single fiber fineness difference, 10 dtex is preferable, More preferably, it is 8 dtex.

  The single fiber fineness of the polyphenylene sulfide fiber of the present invention is preferably a fiber of 0.5 to 15 dtex, more preferably 1.0 to 3.0 dtex. If the single fiber fineness is less than 0.5 dtex, the fineness is too fine, so there is a high possibility that a defect will occur in the card process. If the single fiber fineness exceeds 15 dtex, the atmospheric dust collection efficiency may be low. The single fiber fineness is more preferably 1 to 5 dtex. In the single fiber fineness, the most preferable fineness is 1 to 1.5 dtex, and the medium fineness is 2 to 3 dtex.

  Next, the polyphenylene sulfide undrawn yarn obtained above is hot drawn. The hot stretching is usually performed in warm water having a temperature of 90 to 98 ° C., and a stretching ratio of preferably 2 to 4 times, more preferably 3 to 4 times is employed.

  After the heat stretching treatment, a constant length heat treatment is performed. Constant-length heat treatment refers to performing heat treatment while keeping the length of the yarn substantially constant, and is usually a constant length between a plurality of rollers having substantially the same peripheral speed, and at least a part of the rollers is Heat treatment is performed by using a heating roller or by providing a separate heating means.

  FIG. 1 is an exploded cross-sectional view of a filter material (filter cloth) using a nonwoven fabric made of polyphenylene sulfide fiber obtained in the present invention.

  In FIG. 1, the fiber web 1 that forms the filtration layer on the air inflow surface refers to the surface of the filter material for surface filtration where the air containing dust first comes into contact with the filter material. That is, it indicates a surface on which dust is collected on the filter material surface to form a dust layer. Moreover, the surface on the opposite side is formed by the fiber web 3 that forms the filtration layer of the air discharge surface, and indicates the surface from which the air from which dust has been removed is discharged. Further, a woven fabric (aggregate) 2 made of heat-resistant fibers is sandwiched between the fiber web 1 and the web 3 and made into a felt by a needle punching process, thereby providing mechanical properties such as dimensional stability, tensile strength and wear resistance. It becomes possible to obtain a filter material having excellent strength and dust collection efficiency.

  The PPS fiber obtained by the method for producing a PPS fiber of the present invention can be used as a spun yarn in addition to a non-woven fabric such as a bag filter and papermaking, and the spun yarn can be used as a fabric such as a woven fabric or a knitted fabric.

  Next, the method for producing the polyphenylene sulfide of the present invention will be specifically described with reference to examples. The present invention is not limited by the following examples. Each characteristic value defined in the present invention is obtained by the following method.

(1) Mixing fiber uniformity:
The fiber web after the opener and the carding treatment is taken at random at a magnification of 200 times using a microscope photographer, and five cross-sectional photographs of the fibers are taken. Check the number of fineness varieties out of the number of cross-sections confirmed in 5cm x 5cm squares in each photo, find the mix ratio of fineness varieties for each photo, calculate the standard deviation from them, and mix Uniformity.

  The criteria for determining the uniformity of the mixed fiber are ◯ (good) when the mixed fiber uniformity is 4.0 or less, Δ (slightly better) when the fiber is higher than 4.0 to less than 7.0, 7.0 or higher. In the case of x, it was set as x (bad). ○ (Good) was accepted.

(2) Air dust collection efficiency:
The dust collection efficiency of the filter material was measured by the atmospheric dust calculation method using the atmospheric dust collection efficiency measuring device of FIG. That is, in FIG. 2, an air flow having a filtration wind speed of 1 m / min is passed through the filter material 5 by the blower 8 installed on the downstream side of the filter material 5 (φ170 mm) for 5 minutes, and then the upstream side of the filter material 5 The number A of atmospheric dust (particle size: 0.3-5 μm) was measured by a particle counter (upstream) 4 manufactured by Rion, and the number B of atmospheric dust (particle size: 0.3-5 μm) downstream of the filter 5 was simultaneously measured. Measured with a particle counter (downstream) 6 manufactured by the same company. The measurement sample was n = 3. From the obtained measurement results, the collection efficiency (%) was determined by the following formula.
・ (1- (BA)) × 100
In the above formula, A is the number of upstream atmospheric dust and B is the number of downstream atmospheric dust.

  Judgment criteria for air dust collection efficiency are: ○ (good), dust collection efficiency of particle size of 1 μm or less is 50% or more, 45% to less than 50% is △ (somewhat good), and less than 45% is × (bad) It was. ○ (Good) was accepted.

(3) Pressure loss after dust removal:
The pressure loss after dust removal was measured from the pressure loss measuring device of FIG. That is, in FIG. 3, an air flow having a filtration wind speed of 2.0 m / min was applied to the filter material 5 by the vacuum pump 12 and the flow meter 10 installed on the downstream side of the filter material 5 (φ170 mm). Dust adjusted to a dust concentration of 20 g / m 3 with the dust supplier 14 and the dust disperser 15 was added to the air inflow surface side of the filter material 5 (filtration area 100 cm ² ). Every time the pressure loss measured with the digital manometer 13 increases to 10 mmH ₂ O (980 pa), the pulse jet pressure machine 3 downstream of the filter 5 causes a pulse jet pressure of 3 kgf / cm ² (294 kpa), 0.1 sec. The pressure jet immediately after the pulse jet loading was continuously monitored with the digital manometer 13.

Criteria pressure loss after flicked dust, less than the elapsed time pressure loss 30hr time point _7mH 2 O _(69pa) ○ _{(good), 7mmH} 2 O _(69pa) or 8mmH ₂ O a (78mH2O) hereinafter △ ( Slightly good), a case where it was higher than 8 mmH ₂ O (78 pa) was evaluated as x (bad). ○ (Good) was accepted.

(4) Comprehensive judgment:
If there is at least one x (bad) judgment among the three items in the above criteria for uniformity of mixed fiber, air dust collection efficiency and pressure loss after dust removal, the overall judgment is x (bad). In the case of 3 items, ○ (good) is 2 or more items, the overall judgment is ○ (good), and in 3 items, ○ (good) is 1 item, the overall judgment is Δ. ○ (Good) was accepted.

[Example 1]
Using a single fiber fineness of 3.0 dtex (fiber diameter of 17 μm) and a cut length of 76 mm PPS short fibers (Torucon (R) (registered trademark) S101-3.0T76 mm) manufactured by Toray Industries, Ltd. A spun yarn (total fineness: 600 dtex) having two yarns was obtained. Using this spun yarn, a plain weave fabric was woven to obtain a plain fabric made of PPS spun yarn having a warp density of 26 / 2.54 cm and a cotton yarn density of 18 / 2.54 cm. Using this plain woven fabric as an aggregate, on one side, a single fiber fineness of 2.2 dtex (fiber diameter of 14.5 μm) obtained by spinning and mixing at a mass ratio of 50:50 and a single fiber fineness of 1.0 dtex (fiber diameter) After 9.7 μm) PPS short fibers were carded with an opener, a fiber web obtained by provisional needle punching at a needle needle density of 50 / cm ² was laminated with a basis weight of 194 g / m ² . This fiber web forms a filtration layer on the air inflow surface. On the other side of the woven fabric, a single fiber fineness of 7.8 dtex (fiber diameter: 27.2 μm) and a cut length of 76 mm PPS short fibers (“Torcon (R)” (registered trademark) S101-7.8T51 mm manufactured by Toray Industries, Inc.) ) After 100% carding with an opener, a fiber web obtained by provisional needle punching with a needle needle density of 50 / cm ² was laminated with a basis weight of 220 g / m ² . This fiber web forms a filtration layer on the air discharge surface. Further, the fabric (aggregate) and the above-described fiber web were entangled by needle punching to obtain a filter having a basis weight of 544 g / m ² and a total needle density of 300 needles / cm ² . Table 1 shows the performance of the obtained filter material. The filter material obtained here contracted by the needle punching process, and there was a tendency for the basis weight to be higher than theoretically.

[Example 2]
PPS short fibers having a single fiber fineness of 1.0 dtex (fiber diameter of 9.7 μm) and a single fiber fineness of 2.2 dtex (fiber diameter of 14.5 μm) as fibers constituting the fiber web on the air inflow side. Was obtained in the same manner as in Example 1 except that the fiber was spun and mixed at a mass ratio of 20:80. The performance of the obtained filter material is shown in Table 1.

[Example 3]
As fibers constituting the fiber web on the air inflow surface side, except that the PPS short fibers having a single fiber fineness of 1.0 dtex and a single fiber fineness of 3 dtex were spun and mixed at a mass ratio of 20:80 by spinning and mixing. A filter material was obtained in the same manner as in Example 1. The performance of the obtained filter material is shown in Table 1.

[Comparative Example 1]
As fibers constituting the fiber web on the air inflow surface side, PPS short fibers having a single fiber fineness of 1.0 dtex (fiber diameter of 9.7 μm) and single fiber fineness of 2.2 dtex (fiber diameter of 14.5 μm) are obtained by spinning and mixing. A filter material was obtained in the same manner as in Example 1 except that the PPS short fibers were subjected to a cotton blending operation at a mass ratio of 50:50 and then subjected to an opener and carding treatment. Table 1 shows the performance of the obtained filter material.

[Comparative Example 2]
As fibers constituting the fiber web on the air inflow surface side, PPS short fibers having a single fiber fineness of 1.0 dtex (fiber diameter of 9.7 μm) and single fiber fineness of 2.2 dtex (fiber diameter of 14.5 μm) are obtained by spinning and mixing. A filter material was obtained in the same manner as in Example 1 except that the PPS short fibers were subjected to a cotton blending operation at a mass ratio of 20:80 and then subjected to an opener and carding treatment. Table 1 shows the performance of the obtained filter material.

1: Fiber web forming a filtration layer on the air inflow surface 2: Fabric made of heat-resistant fibers (aggregate)
3: Fiber web forming the filtration layer on the air discharge surface 4: Particle counter (upstream)
5: Filter material 6: Particle counter (downstream)
7: Manometer 8: Blower 9: Pulse jet load machine 10: Flow meter 11: Dust collection filter 12: Vacuum pump 13: Digital manometer 14: Dust feeder 15: Dust disperser 16: Dust collection part 17: Atmospheric dust air 18: Air from which atmospheric dust has been removed 19: Weighed dust 20: Air containing dust 21: Air from which dust has been removed

Claims (4)

  A method for producing polyphenylene sulfide fiber, wherein at least two kinds of fibers having different single fiber fineness are simultaneously spun and mixed.   The method for producing polyphenylene sulfide fibers according to claim 1, wherein the single fiber fineness is in the range of 0.5 to 15 dtex, and the difference in single fiber fineness is 0.5 to 10 dtex.   A nonwoven fabric comprising the polyphenylene sulfide fiber according to claim 1 or 2.   A filter cloth using the nonwoven fabric according to claim 3.

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