JP4450313B2 - Polyphenylene sulfide fiber and industrial fabric - Google Patents

Description

  The present invention relates to a polyphenylene sulfide fiber, and more particularly to a polyphenylene sulfide fiber excellent in bending wear resistance and bending fatigue resistance and an industrial fabric using the same.

  Since polyphenylene sulfide (hereinafter referred to as PPS) is a resin having excellent heat resistance and chemical resistance, industrial parts, fibers, industrial fabrics, films, sheets, plates and the like that make use of these excellent characteristics, etc. It has been widely used as various molded products.

  However, fibers made of PPS, particularly monofilaments, are not only inferior in abrasion resistance (hereinafter referred to as bending abrasion) when subjected to repeated bending and rubbing, but warp yarns in the fiber axis direction when weaving into industrial fabrics. There is a problem that it is inferior in bending durability such as being easily broken, and improvement of these problems has been demanded conventionally.

  Various studies have been made on techniques for improving various properties of PPS fibers, particularly PPS monofilaments.

For example, PPS resin (A) 5 to 99% by weight and (B) polyolefin polymer, conjugated diene polymer, polystyrene polymer, polyamide polymer, polycarbonate polymer, polyphenylene ether polymer, thermoplasticity For a resin composition comprising 1.0 to 95% by weight of at least one thermoplastic resin (B) selected from polyesters, a dehydrogenation catalyst such as an Fe ₂ O ₃ catalyst, a Pd catalyst A thermoplastic resin composition comprising 0.01 to 20% by weight of at least one catalyst (C) selected from deoxygenated catalysts such as deoxygenated catalysts and Cr ₂ O ₃ based catalysts (for example, Patent Document 1) is known, but the melt flow rate (hereinafter referred to as MFR) of this composition and the dispersion state of polyester in the PPS fiber and the dispersion No mention is is Orazu for, according to the study of the present inventors, PPS fibers obtained from this composition was still insufficient in flex abrasion resistance and flexing fatigue resistance both.

Further, in Patent Document 2, 1 to 20% by weight of heat-stabilized nylon 66 is added as an additive having a higher melt viscosity than PPS at the extrusion temperature and having heat resistance deterioration and chemical compatibility with PPS. It is also known for fibers in which the additive is present as individual small elongated spherules parallel to the fiber axis, but according to the study by the inventors, this fiber also has bending wear and bending properties. The fatigue was still not sufficient.
JP-A-7-316428 (page 4-5) Japanese Patent Publication No. 5-83678 (first page)

  The present invention has been made as a result of investigations to solve the above-described problems in the prior art, and is excellent in mechanical properties such as tensile strength and hook strength, and has bending abrasion resistance and bending durability as compared with the prior art. The object is to provide more excellent PPS fibers and various industrial fabrics using the PPS fibers.

As a result of diligent research to achieve the above-mentioned problems, the present inventors have surprisingly found that fibers obtained by melt spinning a resin composition containing polyethylene terephthalate in PPS have flex abrasion and flex durability. Has been found to be a PPS fiber that has been remarkably improved and has a sufficiently high mechanical property, and has reached the present invention.

That is, according to the present invention in order to achieve the above object, relative PPS90~60 wt%, a fiber made of a resin composition containing 10 to 40 wt% of polyethylene terephthalate (A), the polyethylene terephthalate Each spindle is uniformly dispersed in the fiber, its long axis is parallel to the fiber axis, and the diameter of the spindle in the direction perpendicular to the fiber axis is 0.2 to 1.5 μm, In accordance with the bending wear test defined in JIS L-1095-7.10.2B, a friction sample of φ3.0 mm (fiber sample brought into contact with a hard steel wire (SWP-SF)) It is hung under two free rollers (inter-roller distance: 70 mm) provided diagonally at 55 ° angles on the left and right sides of the child, and 0.196 is attached to one end of the fiber through another free roller. Set by applying a load of N / dtex, the fiber sample was reciprocated in contact with the friction element under the conditions of reciprocation frequency: 105 times / min, and reciprocation stroke: 25 mm, and 10 fiber samples were cut for each sample. The number of bending wear cuts obtained by measuring the number of reciprocating bendings until room temperature at room temperature was 9000 to 20000 times, in accordance with the bending fatigue test specified in JIS P-8115 (manufactured by Toyo Seiki) MIT bending fatigue testing machine), load: 0.221 cN / dtex, number of swings: 175 times / minute, swing angle: 270 degrees (135 degrees each to the left and right), Curvature radius: The number of reciprocal bendings until 10 fibers are cut for each same fiber sample under the condition of 0.38 ± 0.03 mm. PPS fibers is provided by the constant bending fatigue number of cuts to obtain an average value is characterized in that 150 to 500 times.

In the PPS fiber of the present invention,
According to ASTM D1238-86, the MFR of the resin composition (A) measured under the conditions of 316 ° C., orifice diameter 2.095 mm, orifice length 8.00 mm and load 5 kg is 100 to 250 g / 10 minutes. And the molecular structure of the PPS is substantially linear ,
Tensile strength measured according to JIS- L1013 is 2.0 to 5.0 cN / dtex, nodule strength is 1.5 to 4.5 cN / dtex, and hook strength is 2.0 to 10.0 cN / dtex. And a monofilament having a diameter of 0.05 to 4.00 mm,
Are mentioned as preferable conditions.

  In addition, the industrial fabric of the present invention comprises the above PPS fiber as at least a part of the constituent material.

  The PPS fiber represented by the monofilament of the present invention maintains excellent heat resistance and moisture and heat resistance, which are the characteristics of PPS, and has excellent bending durability that is difficult to break when subjected to repeated bending and difficult to wear. Since it is excellent in mechanical properties such as strength, tensile elongation, and hook strength, it has a high industrial utility value as an industrial fabric such as papermaking dryer canvas.

  Hereinafter, the present invention will be described in detail.

The PPS fiber of the present invention is a fiber comprising a resin composition in which 10 to 40% by weight of polyethylene terephthalate is blended with 90 to 60% by weight of PPS, and the polyethylene terephthalate is in the form of individual spindles and uniformly dispersed in the fiber. The major axis is parallel to the fiber axis, and the minor axis length, that is, the diameter in the cross section in the direction perpendicular to the fiber axis of the spindle is 0.2 to 1.5 μm . The number of reciprocating wear until cutting in the measured bending wear test is 9000 to 20000 times, and the number of reciprocating bending until cutting in the bending fatigue test measured by the above method is 150 to 500 times. Fiber.

  PPS as used in the present invention is a polymer in which 90% or more of the repeating units of the polymer are composed of p-phenylene sulfide, and can be obtained industrially by polycondensation reaction of sodium sulfide with p-dichlorobenzene. . Further, it may be a polymer obtained by copolycondensation with less than 10 mol% of trichlorobenzene as a branching component.

  In addition, as a raw material PPS, a MFR of 50 to 180 g / 10 minutes, particularly 50 to 150 g / 10 minutes, and a substantially linear molecular structure is preferably used.

  In the case where PPS is obtained by washing PPS after polycondensation with water, it mainly has a sodium carboxylate terminal group at the terminal. Moreover, what washed PPS after polycondensation with the acetic acid aqueous solution, and then washed with water has a carboxylic acid terminal group at the terminal. Furthermore, what washed PPS after polycondensation with the aqueous solution of calcium acetate, and then washed with water has a carboxylate terminal group at the terminal. However, the PPS having a carboxylic acid end group may have a small amount of —COONa end groups, and the PPS having a carboxylic acid metal end group may have a small amount of carboxylic acid end groups.

  When PPS is branched / crosslinked, problems such as poor spinnability and stretchability, and low knot strength of the resulting fiber occur. Therefore, PPS used in the present invention is substantially In particular, it is preferably a linear high polymer.

  In the present invention, commercially available PPS can be obtained and used. As commercial products of PPS, for example, E1880 (MFR: 70 g / 10 min), E2080 (MFR: 100 g / 10 min), E2280 (MFR: 170 g / 10 min) which are PPS having carboxylic acid metal end groups. ) And the like.

The PPS fiber of the present invention is a fiber composed of a resin composition (hereinafter abbreviated as PPS resin composition) in which 10 to 40% by weight of polyethylene terephthalate is blended with 90 to 60% by weight of PPS. When the polyethylene terephthalate is less than 10% by weight, the effect of improving the bending durability does not appear, and when it exceeds 40% by weight, the polyethylene terephthalate tends to aggregate in the PPS, and the strength spots and fineness spots of the resulting fibers are preferably increased. Absent. Therefore, in order to obtain high strength and high bending durability, it is important that the polyethylene terephthalate blended in the PPS is 10 to 40% by weight, and it is particularly preferably in the range of 15 to 30% by weight.

  The PPS resin composition referred to in the present invention preferably has an MFR of 100 to 250 g / 10 minutes, more preferably 130 to 200 g / 10 minutes.

  When the MFR of the PPS resin composition is larger than 250 g / 10 min, in terms of durability of the fiber, particularly bending durability, a dryer canvas for papermaking, a net conveyor for thermal bonding method non-woven fabric thermal bonding process, a belt for conveying in a dryer and a heat treatment machine, or It may be insufficient and unsuitable for use in industrial applications such as filters, and on the other hand, if MFR is less than 100 g / 10 min, melt spinning may tend to be difficult.

In the PPS fiber of the present invention, polyethylene terephthalate contained in the fiber is in the form of individual spindles and uniformly dispersed in the fiber, the major axis is parallel to the fiber axis, and the minor axis length, that is, the spindle It is important that the diameter in the cross section perpendicular to the fiber axis of the body is 0.2 to 1.5 μm.

If the dispersion diameter of the polyethylene terephthalate dispersed in the PPS fiber is less than 0.2 μm, the effect of improving the bending durability does not appear sufficiently, and if it exceeds 1.5 μm, both the strength and the bending durability tend to decrease. is there. Therefore, it is important that the dispersion diameter of the polyethylene terephthalate dispersed in the PPS fiber is 0.2 to 1.5 μm, and it is particularly preferable to be in the range of 0.7 to 1.4 μm.

  In addition, the PPS fiber of the present invention has a tensile strength measured according to JIS-L1013 of 2.0 to 5.0 cN / dtex, a knot strength of 1.5 to 4.5 cN / dtex, and a hook strength of the same. It is desirable to have each characteristic of 2.0-10.0 cN / dtex. If the tensile strength, knot strength, and hook strength are less than the lower limit of the above strength range, they tend to be insufficient for use in industrial applications, and if the upper limit of the strength range is exceeded, bending durability tends to be remarkably reduced.

A general method is used as a method for producing the PPS resin composition used in the present invention. The most common method is to uniformly mix PPS and polyethylene terephthalate with a suitable mixer such as a tumbler or Henschel mixer, and supply the mixture to a twin-screw extruder to heat PPS to a temperature above its melting point. After melting and kneading, if necessary, filter with filters to remove foreign matter, extrude into a gut shape, and cut after cooling. According to this method, the composition is processed into pellets and used Can do.

  Next, the production method of the PPS fiber having the above excellent characteristics will be described by taking a monofilament as an example, but the present invention is not limited to this.

  In the production method of the PPS fiber of the present invention, the PPS resin composition is melt-spun. As described above, the MFR of the PPS resin composition used is 250 g / 10 min or less, particularly 200 g / 10 min or less. preferable.

  First, for example, a PPS resin composition melted at a melting temperature of about 300 to 350 ° C. by an extruder is extruded from a nozzle and cooled in warm water of 70 ° C. or higher through an air layer or an inert gas layer. Next, the obtained undrawn yarn is subsequently subjected to a pressure saturated steam atmosphere with a gauge pressure of 0.98 to 49 kPa, preferably a gauge pressure of 0.98 to 20 kPa, and for 0.1 to 10.0 seconds, preferably During 0.5 to 8.0 seconds, primary stretching is performed by 3.3 to 4.1 times. Subsequently, in an atmosphere of 130 to 180 ° C., preferably 140 to 170 ° C., multi-stage stretching is performed so that the total draw ratio is 4.0 to 7.0 times in the range of 1.05 to 1.8 times. Subsequently, by performing a relaxation heat treatment of 0 to 20% in an atmosphere of 110 to 175 ° C., preferably 110 to 160 ° C., the number of flexing wear cuts as described above is 9000 to 20000 times, and the number of flexing fatigue cuts is 150 to 500. The PPS monofilament according to the present invention having both excellent bending durability and tough mechanical properties can be obtained.

  If the gauge pressure of the pressurized saturated water vapor pressure in the primary stretching is less than the above range, bending durability will be reduced, and if it exceeds the above range, super draw will occur and stable stretching will be performed. Cannot be implemented.

  If the stretching time in the primary stretching is less than the above range, the bending durability is lowered, and if it exceeds the above range, super draw occurs, and it becomes impossible to perform the stable stretching similarly to the above.

  By the way, when using, for example, warm water or dry hot air other than pressurized saturated water vapor as the heat medium for primary stretching, the strength required as a monofilament may not be obtained. About this cause, warm water having a temperature lower than that of pressurized saturated water vapor or dry hot air having a low thermal conductivity cannot heat PPS to Tg or more in the primary stretching, and cannot sufficiently align molecules. This is probably because of this.

  Therefore, the conditions of the gauge pressure and stretching time of the pressurized saturated water vapor pressure in primary stretching are the conditions for obtaining a PPS monofilament capable of performing stable stretching and having both excellent bending durability and tough mechanical properties. This is an important condition.

  Furthermore, when performing multistage stretching, it is desirable to perform the secondary stretching and subsequent processes in an atmosphere of 130 to 180 ° C, preferably 140 to 170 ° C. If the drawing temperature is less than the above range, yarn breakage occurs and stable yarn-making property cannot be obtained, and if it exceeds the above range, bending durability is reduced. The cause of this is not clear at the present time, but is presumed to be a phenomenon that occurs because the crystallization of the amorphous part is promoted by the high thermal history and the flexibility is impaired. In this temperature atmosphere, bending durability and tough mechanical properties are obtained by performing multi-stage stretching in the range of 1.05 to 1.8 times so that the total draw ratio is 4.0 times to 7.0 times. Thus, a PPS monofilament having both of the above can be obtained.

  Next, the relaxation heat treatment is desirably performed in an atmosphere of 110 to 175 ° C, preferably 110 to 160 ° C. If the heat treatment temperature is less than the above range, sufficient heat treatment is not performed, and if it exceeds the above range, bending durability is lowered, which is not preferable. The cause of this is not clear at the present time, but is presumed to be a phenomenon that occurs because the high thermal history promotes crystallization of the amorphous part and impairs flexibility. In this atmosphere, a relaxation heat treatment is performed under the condition of 0 to 20%, whereby a PPS monofilament having both bending durability and tough mechanical properties can be obtained.

  According to the production method of the PPS monofilament, since a high temperature including the melting point of PPS or higher is not required in the stretching or heat setting process, it is easy to take appropriate conditions, and the bending durability is excellent in productivity. An excellent PPS monofilament can be produced efficiently.

  The PPS fiber of the present invention exhibits a particularly excellent effect when it is a monofilament having a diameter of 0.050 mm to 4.00 mm, but also includes multifilaments other than monofilaments. In addition to the single structure, the fiber form includes various forms such as a core-sheath composite yarn, a sea-island composite yarn, a bimetal composite yarn, and a multilayer composite yarn.

  The PPS monofilament referred to in the present invention is a continuous yarn composed of one single yarn. On the other hand, the PPS multifilament referred to in the present invention is a continuous yarn formed by aggregating a plurality of single yarns.

  The cross-sectional shape perpendicular to the fiber axis direction of the PPS fiber of the present invention represented by monofilament (hereinafter referred to as cross-sectional shape or cross-section) is a circle, a flat shape, a square shape, a half moon shape, a triangle shape, a polygon having 5 or more corners, a multi It may have any cross-sectional shape such as a leaf shape, a dogbone shape, or a saddle shape.

  When the PPS fiber typified by the monofilament of the present invention is used as a constituent material of an industrial fabric, the cross-sectional shape of the fiber is preferably a circle or a flat shape. In particular, when PPS monofilament is used as the warp yarn for a papermaking dryer canvas, a monofilament having a flat cross-sectional shape is preferably used from the viewpoint of effectively exhibiting antifouling properties and flatness of the canvas. The flat in the present invention means an ellipse, a square or a rectangle. In addition to an exact ellipse, a square or a rectangle defined mathematically, a shape substantially similar to an ellipse, a square or a rectangle, for example, a square and a rectangle. It includes a shape with rounded four corners. In the case of an ellipse, the length of the major axis (LD) and the length of the minor axis (SD) intersecting at right angles at the center of the ellipse satisfy the following formula. It is preferable that the long side length (LD) and the short side length (SD) of the rectangle satisfy the relationship of Expression 1.0 ≦ LD / SD ≦ 10, respectively.

  The length of the line segment passing through the center of gravity of the cross section of the PPS monofilament can be appropriately selected depending on the application, but is preferably in the range of 0.05 to 4.0 mm.

  The industrial fabric of the present invention is a paper-made dryer canvas using PPS fibers typified by the monofilament of the present invention as at least a part of the weft and / or warp of the fabric, a net conveyor for thermal bonding method nonwoven fabric thermal bonding process, It is a conveyor belt or various filters in a dryer and a heat treatment machine, and these industrial fabrics exhibit useful properties such as excellent bending durability, heat resistance and chemical resistance.

  Here, paper dryer canvas is a variety of fabrics such as plain weave, double weave, and triple weave (a spiral structure with a repetitive structure in which spiral filament monofilaments that follow each other are meshed, and the meshing part is woven by monofilaments on a substantially straight line. Woven fabric used to dry the paper in the dryer of the paper machine. The belt fabric for the thermal bonding process of the nonwoven fabric is a fabric for allowing the nonwoven fabric to pass through a furnace in order to fuse the thermal adhesive fibers such as low melting point polyethylene constituting the nonwoven fabric. Heavy woven fabrics. Further, the conveyor belt in the dryer and heat treatment machine refers to a fabric that transports the semi-finished product in the high-temperature zone for drying, thermosetting, sterilizing, heat cooking and the like of various semi-finished products. Furthermore, various filters are woven fabrics used for filtering high-temperature liquids, gases, powders, and the like.

  The present invention will be described in more detail below with reference to examples of PPS fibers represented by monofilaments, which are one of the preferred forms of the fibers of the present invention, industrial fabrics using the PPS fibers, and methods for producing PPS fibers. .

  First, each physical property evaluation method performed in the present example and the comparative example will be described.

Number of bending wear cuts:
It measured according to the bending abrasion test prescribed | regulated to JISL-1095-7.10.2B. That is, two free rollers in which fibers brought into contact with a fixed friction element (hard steel wire (SWP-SF)) having a diameter of φ3.0 mm are provided obliquely downward at 55 ° angles on the left and right sides of the friction element. It is hung under (distance between rollers: 70 mm) and set on one end of the fiber with a load of 0.196 cN / dtex passing over another free roller. The fiber sample was contacted and reciprocated with a friction element under the conditions of a reciprocation frequency of 105 times / minute and a reciprocation stroke of 25 mm, and the number of reciprocal bendings until 10 monofilaments were cut for each fiber sample was measured at room temperature. The average value was obtained. The larger this average value, the better the bending wear resistance.

Bending fatigue cutting frequency:
It measured according to the bending fatigue test prescribed | regulated to JISP-8115. That is, with a bending fatigue testing machine (manufactured by Toyo Seiki; MIT bending fatigue testing machine), load: 0.221 cN / dtex, number of swings: 175 times / minute, swing angle: 270 degrees (135 degrees on each side), fiber The radius of curvature of the left and right bent surfaces of the folding piece to be sandwiched: Under the conditions of 0.38 ± 0.03 mm each, the number of reciprocating bendings for each of the ten fibers for each same fiber sample is measured to obtain an average value. It was. It represents that bending fatigue property is so favorable that this average value is large.

Measurement of tensile strength, tensile elongation, and hook strength:
According to JIS L1013, measurement was performed under conditions of a test length: 250 mm and a tensile speed: 300 mm / min. The hook strength is a value obtained by conversion per decitex unit of the measurement sample.

Melt flow rate (MFR):
According to ASTM D1238-86, it is a value measured under the conditions of 316 ° C., orifice diameter 2.095 mm, orifice length 8.00 mm, and load 5 kg, and is expressed as an outflow polymer amount (g) per 10 minutes. .

Intrinsic viscosity of polyethylene terephthalate :
Using an Ostwald viscometer, the relative viscosity ηr of a solution in which 8 g of the sample was dissolved in 100 ml of orthochlorophenol was measured at 25 ° C., and the intrinsic viscosity (IV) was calculated from the approximate expression IV = 0.0242 ηr + 0.2634.
However, ηr = (t × d) / (t ₀ × d ₀ )
t: Dropping time of solution (second)
t ₀ : Fall time of orthochlorophenol (seconds)
d: Density of solution (g / cc)
d ₀ : Orthochlorophenol density (g / cc)

Dispersion diameter of polyethylene terephthalate in PPS fiber:
An inclined cross section in the 45 ° direction was cut out on the fiber axis of the PPS fiber, and the cross section was subjected to alkali weight loss treatment in a 20 wt% NaOH aqueous solution at 80 ° C. for 30 minutes to elute polyethylene terephthalate in the PPS fiber.
The cross section after the alkali weight reduction treatment was observed with a scanning electron microscope (hereinafter abbreviated as SEM) at a magnification of 6000, and all the diameters of holes present in 100 μm ² (10 μm × 10 μm) were measured, and the average value was dispersed. The diameter.

Steam heat resistance:
Using a super-accelerated life test apparatus PC-305SIII manufactured by Hirayama Seisakusho, steam heat treatment was performed for 40 days under the conditions of 138 ° C. and 0.294 MPa, and the strength retention was calculated from the tensile strength before and after the heat treatment.

Example 1
20% by weight of polyethylene terephthalate (manufactured by Toray Industries, Inc., hereinafter abbreviated as PET) 20% by weight is mixed with 80% by weight of PPS (E2080, manufactured by Toray Industries, Inc.) having an MFR of 100 g / 10 min. The resin blend is supplied to a twin screw extruder (PCM-30 manufactured by Ikegai Kogyo Co., Ltd.) rotated at a high speed of 320 ° C., two kneading zones and a screw speed of 300 rpm, and discharged after being discharged from the die. Was immediately cooled in ice water to fix the structure.

Further, after discharging from the die, the gut in a state of being rapidly cooled in ice water to fix the structure and compatibilized was supplied to the strand cutter to produce PPS pellets (A1).
The MFR of the PPS pellet (A1) was 180 g / 10 minutes.
PPS pellets (A1) were prepared by drying at 135 ° C. under reduced pressure for 8 hours.

  The PPS pellets (A1) are continuously supplied to a single-screw extruder having a diameter of 40 mm (L / D = 25), and the molten polymer melted at 320 ° C. is passed through a filtration layer in a spinning pack through a gear pump, and then circular. It was extruded into a fiber form from a spinneret for cross-sectional yarn and cooled with hot water at 80 ° C.

  Next, the cooling yarn was subjected to a primary stretching of 3.8 times in a pressurized saturated steam atmosphere with a gauge pressure of 1.96 kPa for 4.1 seconds and a secondary stretching of 1.2 times in hot air at 150 ° C. Then, a monofilament having a circular cross section with a diameter of 0.45 mm was obtained by performing a relaxation heat treatment under conditions of 140 ° C. and 0.98 times. Table 1 shows the test results of the strength and bending durability of the obtained monofilament and the measurement results of the dispersed diameter of PET in the PPS fiber.

Comparative Example 1
PPS (Toray Industries, Inc., E2080) pellets (B1) with an MFR of 100 g / 10 min were prepared by drying at 135 ° C. under reduced pressure for 8 hours.

  A monofilament having a circular cross section with a diameter of 0.45 mm was obtained by spinning in the same manner as in Example 1 except that the raw material was changed to PPS pellets (B1). Table 1 shows the test results of the strength and bending durability of the obtained monofilament and the measurement results of the dispersed diameter of PET in the PPS fiber.

Comparative Example 2
PPS pellets (B2) were produced in the same manner as in Example 1 except that the weight ratio of PPS and PET in Example 1 was 98: 2.
The MFR of the PPS pellet (B2) was 130 g / 10 minutes.

  A monofilament having a circular cross section with a diameter of 0.45 mm was obtained by spinning in the same manner as in Example 1 except that the raw material was changed to PPS pellets (B2). Table 1 shows the test results of the strength and bending durability of the obtained monofilament and the measurement results of the dispersed diameter of PET in the PPS fiber.

Example 2
Except for using a resin blend in which 80% by weight of PPS (manufactured by Toray Industries, Inc., E2080) 80% by weight of MFR of 100 g / 10 min was mixed with 20% by weight of PET (manufactured by Toray Industries, Inc.) having an intrinsic viscosity of 0.75. A PPS pellet (A2) was produced in the same manner as in Example 1.
The MFR of the PPS pellet (A2) was 230 g / 10 minutes.

  A monofilament having a circular cross section with a diameter of 0.45 mm was obtained by spinning in the same manner as in Example 1 except that the raw material was changed to PPS pellets (A2). Table 1 shows the test results of the strength and bending durability of the obtained monofilament and the measurement results of the dispersed diameter of PET in the PPS fiber.

Example 3
PPS pellets (A3) were produced in the same manner as in Example 1 except that the weight ratio of PPS and PET in Example 1 was changed to 65:35.
The MFR of the PPS pellet (A3) was 240 g / 10 minutes.

  A monofilament having a circular cross section with a diameter of 0.45 mm was obtained by spinning in the same manner as in Example 1 except that the raw material was changed to PPS pellets (A3). Table 1 shows the test results of the strength and bending durability of the obtained monofilament and the measurement result of the dispersed diameter of PET in the PPS fiber.

Comparative Example 3
PPS pellets (B3) were produced in the same manner as in Example 1 except that the weight ratio of PPS and PET in Example 1 was changed to 50:50.
The MFR of the PPS pellet (B2) was 540 g / 10 minutes.

  A monofilament having a circular cross section with a diameter of 0.45 mm was obtained by spinning in the same manner as in Example 1 except that the raw material was changed to PPS pellets (B2). Table 1 shows the test results of the strength and bending durability of the obtained monofilament and the measurement results of the dispersed diameter of PET in the PPS fiber.

Example 4
The PPS pellet (A1) used in Example 1 was melted so that the polymer temperature was 315 ° C. with a single screw extruder under a vacuum of 10 Torr, and the molten polymer had 5 μ pores in the spin pack. After filtration through a metal filter, spinning is performed through a spinneret having 50 holes with a hole diameter of 0.30 mm and a hole depth / hole ratio of 4, and the discharge amount is adjusted to the yarn production conditions so that the wound yarn is 220 dtex. It was. An insulating tube is installed directly under the base, and an atmosphere having an atmosphere temperature of 220 ° C. 10 cm below the base is passed through. The yarn is immediately cooled with cold air of 25 ° C., and is cooled and solidified on the unstretched yarn. A water-based emulsion oil was applied so that the amount of oil solids attached to the drawn yarn was 1.5% by weight. Subsequently, it was taken up by a take-up roll heated to 50 ° C. rotating at a speed of 600 m / min, and 1.30 between the undrawn yarn and a feed roll continuously heated to 90 ° C. without being wound up once. Double primary stretching was performed. Subsequently, 3.0-fold secondary stretching was performed between the feed roll and the first stretching roll at 105 ° C. Further, the yarn is subjected to a relaxation treatment of 0.98 times between the second drawing roll and the relaxation roll, and wound with a winder to obtain a PPS multifilament of 225 dtex (50 filaments, single fiber fineness 4.5 dtex). Table 1 shows the test results of the strength and elongation of the obtained multifilament and the bending durability, and the measurement results of the dispersed diameter of PET in the PPS fiber.

Comparative Example 4
A PPS multifilament with 225 dtex (50 filaments, single fiber fineness 4.5 dtex) was obtained in the same manner as in Example 4 except that the raw material was changed to the PPS pellet (B1) used in Comparative Example 1. Table 1 shows the test results of the multifilament strength and bending durability, and the measurement results of the dispersed diameter of PET in the PPS fiber.

  As is apparent from the results in Table 1, monofilaments (Examples 1 to 3) obtained from PPS pellets having an MFR of 300 g / 10 min or less and having a PET dispersion diameter in the fiber of 0.2 to 1.5 μm by SEM observation, and The multifilament (Example 4) had extremely excellent bending resistance with a bending wear number of 9500 times or more and a bending fatigue number of 240 times or more, as well as good tensile strength and elongation and hook strength. Further, the strength after steaming was not inferior to that of PPS single monofilament, and was excellent in heat resistance.

In contrast, the monofilament not containing PET (Comparative Example 1) and the multifilament (Comparative Example 4), and the blending amount of PET are less than specified, and the dispersion diameter of PET in the fiber by SEM observation is less than 0.2 μm. Each of the monofilaments (Comparative Example 2) had insufficient bending resistance. Further, monofilaments obtained from PPS pellets (Comparative Example 3) in which the blending amount of PET is larger than specified, the dispersion diameter of PET in the fiber by SEM observation is larger than 1.5 μm, and the MFR is larger than 300 g / 10 min. ) Was insufficient in bending resistance and further caused a reduction in strength due to steaming because of the high PET ratio.

Example 5
Using the PPS monofilament obtained in Example 1 for weft and warp, a double woven paper making dryer canvas was prepared. When this dryer canvas constituting yarn was checked for cracks, no cracks were found.

  Further, even when the obtained dryer canvas was actually used, yarn cracking did not occur, and further, strength reduction due to hydrolysis did not occur even in a high-temperature and high-humidity environment, and thus the dryer canvas was excellent.

Comparative Example 5
For comparison, the PPS monofilament obtained in Comparative Example 1 was used as a weft and a warp to produce a double woven papermaking dryer canvas. When the yarn breakage of this dryer canvas yarn was checked, there were 8 yarn breaks per 100 m ^{2 of} canvas.

  From the results of Example 5 and Comparative Example 5, it can be seen that the dryer canvas using the PPS monofilament of the present invention has excellent bending durability.

  As described above, the PPS fiber typified by the monofilament of the present invention has excellent bending durability that is difficult to break and wear when subjected to repeated bending, as well as tensile strength, tensile elongation, and hook strength. Since it is excellent in mechanical properties, it has high industrial utility value as an industrial fabric such as papermaking dryer canvas.

Claims (5)

It is a fiber comprising a resin composition (A) in which 10 to 40% by weight of polyethylene terephthalate is blended with 90 to 60% by weight of polyphenylene sulfide, and the polyethylene terephthalate is uniformly dispersed in the fiber in the form of individual spindles. The major axis is parallel to the fiber axis, and the diameter of the spindle in the cross section in the direction perpendicular to the fiber axis is 0.2 to 1.5 μm, as defined in JIS L-1095-7.10.2B. In accordance with the bending abrasion test, a free φ3 mm friction element (a fiber sample brought into contact with a hard steel wire (SWP-SF) was provided obliquely below each of the left and right angles of 55 degrees of the friction element. Hang it under 2 rollers (distance between rollers: 70 mm) and set a load of 0.196 cN / dtex on one end of the fiber through another free roller. Then, the fiber sample was contacted and reciprocated with the friction element under the conditions of the number of reciprocations: 105 times / min and the reciprocation stroke: 25 mm. According to the bending fatigue test (Toyo Seiki; MIT bending fatigue tester) according to the bending fatigue test specified in JIS P-8115, the number of bending wear cuts obtained by measuring the average value was 9000 to 20000 times. Load: 0.221 cN / dtex, Number of swings: 175 times / minute, Swing angle: 270 degrees (135 degrees to the left and right), Curvature radius of the left and right folded surfaces of the folding frame sandwiching the fiber sample: 0.38 ± 0 each Bending fatigue cutting where the average value was obtained by measuring the number of reciprocating bendings until 10 fibers were cut for each same fiber sample under the condition of 0.03 mm. Polyphenylene sulfide fiber number, characterized in that 150 to 500 times.   The resin composition (A) has a melt flow rate of 100 to 250 g / 10 measured at 316 ° C., an orifice diameter of 2.095 mm, an orifice length of 8.00 mm and a load of 5 kg in accordance with ASTM D1238-86. 2. The polyphenylene sulfide fiber according to claim 1, wherein the polyphenylene sulfide fiber is substantially linear and the molecular structure of the polyphenylene sulfide is substantially linear. Tensile strength measured according to JIS-L1013 is 2.0 to 5.0 cN / dtex, nodule strength is 1.5 to 4.5 cN / dtex, and hook strength is 2.0 to 10.0 cN / dtex. The polyphenylene sulfide fiber according to claim 1 or 2 . The polyphenylene sulfide fiber according to any one of claims 1 to 3 , which is a monofilament having a diameter of 0.05 to 4.00 mm. The industrial fabric which uses the polyphenylene sulfide fiber of any one of Claims 1-4 as at least one part of a constituent material.