JP2013100615A - Polyphenylene sulfide monofilament having flat cross section, and industrial fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PPS (polyphenylene sulfide) monofilament capable of improving occurrence of thread breakage and split yarn when weaving warp yarns or inserting weft yarns in production of an industrial fabric, suppressing occurrence of scraping chips by abrasion, exerting excellent process passability, and making surface smoothness of an industrial fabric in extraordinary good state, and an industrial fabric.SOLUTION: A PPS monofilament contains a 0.5-5.0 wt.% of a polyamide resin as a constituent other than a polyphenylene sulfide resin. In the PPS monofilament having a flat cross section, the shape of a cross section perpendicular to a fiber axis direction is in a flat octagon shape, the interior angles of angle parts facing a center part of the cross section are the same, the Dmax/Dmin is within the range of 1.2-8.0 when having a Dmax of a maximum thickness at a center part of the octagon and a Dmin of a minimum thickness at both end parts where the thickness at a short side is D, the tensile strength measured under the standard of the JIS2003 L1013 is equal to or greater than 2.0 cN/dtex, the tensile elongation likewise is 30% or more and 70% or less, and the hooking strength likewise is equal to or greater than 3.0 cN/dtex.

Description

  The present invention is superior in abrasion resistance than the prior art, exhibits sufficient mechanical properties, and further exhibits stable processability and surface smoothness to industrial fabrics. The present invention relates to a flat cross-sectional polyphenylene sulfide monofilament that can be suitably used as a constituent material of a woven fabric and an industrial woven fabric using the same.

  Polyphenylene sulfide (hereinafter referred to as PPS) is excellent in heat resistance, chemical resistance, flame retardancy and the like, and can be melt-molded. Widely used as and fiber. In particular, PPS fibers are used in various applications such as industrial fabrics such as paper-making dryer canvas, filters and brush hair materials, taking advantage of their excellent heat resistance, chemical resistance and flame retardancy.

  However, fibers made of PPS have problems that physical properties such as tensile strength, knot strength and hook strength, and bending properties are insufficient compared to polyester fibers and polyamide fibers, and more recently. With the introduction of the latest large-scale, high-speed looms from papermakers, there is a growing demand for the realization of PPS monofilaments with improved processability during weaving. For this reason, various proposals have been made for the purpose of improving these physical characteristics and improving processability during weaving.

  For example, the PPS undrawn yarn is stretched in one step at a ratio equal to or higher than the natural stretch ratio, and then subjected to a constant length heat treatment at 150 to 260 ° C. and higher than the first stage stretching temperature, PPS fibers with improved mechanical properties, heat resistance, and chemical resistance (for example, see Patent Document 1) or PPS by stretching in two stages so as to be 1 to 2 times the draw ratio in the first stage. The undrawn yarn obtained by melt spinning is stretched 2 to 7 times at 80 to 260 ° C., and then drawn in a dry heat atmosphere of 285 to 385 ° C. with a draw ratio of 0.8 to 1.35 and 0.1 to 30 Proposed PPS fiber (for example, see Patent Document 2) that has a tensile strength of 3.5 g / d or more and a hook strength of 2.5 g / d or more with improved bending wear and bending fatigue characteristics by heat treatment for 2 seconds. However, PPS fibers and PPS monofilaments obtained with these technologies Although they have some strength and bending resistance, they are actually used as industrial textile yarns, especially PPS monofilaments with high flatness (PPS monofilaments with very long long sides compared to short sides) In such cases, cutting-edge high-speed large-scale looms, which have been increasing in recent years, are extremely productive, including warp breakage caused by impact during warping and weft breakage caused by impact during high-speed driving. The problem of lowering has become apparent.

  Further, the present inventors also made the cross-sectional shape of the PPS monofilament approximately rectangular, a shape having an appropriate bulge at the center in the cross-sectional width direction, and a tensile elongation of 42% or more and 70% or less, A flat cross-sectional polyphenylene sulfide monofilament (see, for example, Patent Document 3) characterized in that the tensile strength has a tensile strength retention rate of 130% or more with respect to the tensile strength has been proposed. Although thread breakage and thread cracking are improved in the processing process for industrial fabrics, since the cross-sectional shape of the yarn has a bulge, it also has a bulge in the long side direction of the PPS monofilament even when it is made into an industrial fabric. Fingers that it is insufficient as a PPS monofilament applied to industrial fabrics that require improved surface smoothness There is that is made.

JP-A-64-3961 JP-A-4-222217 JP 2010-7193 A

  In view of the circumstances as described above, the present invention has been achieved as a result of studying the solution of problems in the prior art as an issue.

  That is, the object of the present invention is to exhibit extremely stable process passage without thread breakage or thread breakage even when used on the state-of-the-art high-speed large-scale loom, and the occurrence of scraping debris due to wear is suppressed. A flat cross-sectional PPS monofilament that can be suitably used as a constituent material of an industrial woven fabric, which can simultaneously realize even better surface smoothness than an industrial woven fabric using a flat cross-sectional PPS monofilament. Is to provide.

  In order to achieve the above object, according to the present invention, a PPS comprising a thermoplastic resin composition mainly composed of a PPS resin containing 0.5 to 5.0% by weight of a polyamide resin as a component other than a polyphenylene sulfide resin. A monofilament, the shape of the cross section perpendicular to the fiber axis direction is a flat octagonal shape, the internal angle of the corner facing the center of the cross section is the same, and when the thickness of the short side is D, Dmax / Dmin is in the range of 1.2 to 8.0 when Dmax where the thickness of the central part of the square is maximum and Dmin where the length of both ends is the shortest, measured according to JIS2003L1013 The tensile strength is 2.0 cN / dtex or more, the tensile elongation is 30% or more and 70% or less, and the hook strength measured by the same method is 3.0 cN / dtex or more. Flat cross PPS monofilament is provided, wherein.

In the flat cross-sectional PPS monofilament of the present invention,
That at least a pair of inner angles of the corners facing the center of the cross section is in the range of 120 ° to 150 °,
The flatness represented by L / Dmax from the length L of the long side and the above Dmax is 1.15 to 10.00, both of which are mentioned as preferable conditions, and further when these conditions are satisfied An excellent effect can be exhibited.

  The industrial fabric of the present invention is characterized by using the flat cross-sectional PPS monofilament as at least a part of warp and / or weft, and uses the flat cross-sectional PPS monofilament as a constituent material, so that it is very stable. Since an industrial fabric having excellent process smoothness and surface smoothness can be obtained, it can be expected to exhibit a very suitable effect particularly when used as a papermaking fabric.

  According to the present invention, the wear resistance is superior to that of conventional PPS monofilaments, sufficient mechanical properties are exhibited, and further, good process passability is exhibited during processing into industrial fabrics. Therefore, it is possible to obtain flat cross-sectional PPS monofilaments and industrial fabrics that can be used very suitably as constituent materials for industrial fabrics typified by papermaking fabrics and the like. .

(A)-(c) is sectional drawing perpendicular | vertical to the fiber axis direction which shows the cross-sectional shape of the flat octagonal cross-section PPS monofilament which satisfy | fills prescription | regulation of this invention. Schematic which showed the measurement location of each site | part, such as long side L and short side thickness Dmin, Dmax in the flat octagonal cross-section PPS monofilament of this invention. (D)-(f) is sectional drawing perpendicular | vertical to the fiber axis direction which shows the cross-sectional shape of the flat cross-sectional PPS monofilament which does not satisfy | fill the prescription | regulation of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  1A to 1C are cross-sectional views perpendicular to the fiber axis direction showing the cross-sectional shape of a flat cross-sectional PPS monofilament that satisfies the provisions of the present invention, and FIGS. It is sectional drawing perpendicular | vertical to the fiber-axis direction which shows the cross-sectional shape of the PPS monofilament which does not satisfy | fill regulation of (2). Moreover, FIG. 2 is the schematic which showed the measurement location of each site | parts, such as thickness Dmin and Dmax of a short side, and the long side L in the PPS monofilament of this invention.

  The flat cross-sectional PPS monofilament of the present invention is characterized in that the cross-sectional shape perpendicular to the fiber axis direction is a flat octagonal shape.

  By making the shape of the cross section perpendicular to the fiber axis direction a flat octagonal shape, it is possible to greatly improve the scraping of the monofilament due to the contact between the PPS monofilaments when weaving the industrial fabric. That is, when the flat cross-sectional PPS monofilament is used as a weft, the cross-sectional shape of the flat PPS monofilament is a substantially octagonal shape at the contact portion that intersects the weft when used as a warp. As a result, the wear of the monofilaments, particularly the wear at the corners, is greatly reduced, and the occurrence of scraps and the like caused by wear when the monofilaments are in contact with each other is reduced.

  Furthermore, since the flat cross-sectional PPS monofilament of the present invention has a flat shape at the long side, the flat part of the flat cross-sectional PPS monofilament is present on the surface of the industrial fabric. This makes it possible to obtain an industrial fabric having excellent surface smoothness.

  In the present invention, in the cross section perpendicular to the fiber axis direction of the PPS monofilament, the internal angles (for example, ∠A and ∠A ′ in FIG. 2) of the corner portions facing the central portion of the cross section are the same. It is a feature.

  Here, when the internal angles of the corners facing the center of the cross section are not the same, a distorted flat octagonal shape is formed, and the surface smoothness is lacked when an industrial fabric is formed.

  In addition, the cross-sectional shape of the flat cross-sectional PPS monofilament of the present invention may have some roundness at each corner.

  The flat cross-sectional PPS monofilament of the present invention has Dmax where the thickness of the central part of the flat octagonal cross section is maximum when D is the thickness of the short side, and Dmax / Dmin is 1.2 to 8.0, but in the range of 1.2 to 4.0, the generation of debris due to scraping of the flat cross-sectional PPS monofilament during weaving is further suppressed. Therefore, more favorable effects can be expected.

  That is, the case where Dmax / Dmin is less than 1.2 is a shape in which the flat cross-sectional PPS monofilament approximates a rectangle instead of an octagonal cross section ((d) and (f) in FIG. 3). On the other hand, the case where Dmax / Dmin exceeds 8.0 is a shape ((e) of FIG. 3) in which the shape of the flat cross-sectional PPS monofilament approximates a hexagon.

  When the cross-sectional shape of the flat cross-sectional PPS monofilament is a shape outside the present invention as described above, when these flat cross-sectional PPS monofilaments are used as constituent materials for industrial fabrics, the corners of the PPS monofilament having a generally rectangular or hexagonal shape are used. Is in contact with the weft and / or warp, leading to extremely undesirable results such as the occurrence of scraping.

  The PPS resin used in the present invention means a polymer containing a phenylene sulfide unit in which the repeating unit of the polymer is a p-phenylene sulfide unit or an m-phenylene sulfide unit. Among these polymers, a polymer in which 90% or more of the repeating units are composed of p-phenylene sulfide units is preferably used.

  A PPS polymer that can be used particularly preferably in the present invention can be produced by polycondensation reaction of sodium sulfide with p-dichlorobenzene, but the p-dichlorobenzene has less than 10 mol% of trichlorobenzene as a branching component. It may be produced by polycondensation.

  In the present invention, in accordance with ASTM D1238-86, the melt indicated by the amount (g) of spilled polymer per 10 minutes measured under the conditions of 316 ° C., orifice diameter 2.095 mm, orifice length 8.00 mm, and load 5 kg. PPS having a flow rate (hereinafter referred to as MFR) of about 20 to 300 g / 10 min can be used, but in particular, MFR is 70 to 200 g / 10 from the standpoints of balance of strength and elongation, diameter unevenness, wear characteristics, and yarn production. PPS of about a minute can be preferably used.

  Here, as a PPS resin which can be used as a commercial item, E1880, E2080, E2280, E2481, M2488, M2588, etc. of Toray Industries, Inc. can be mentioned, for example.

  Even if the PPS resin used in the present invention is not the PPS chip available as the above-mentioned commercial product, there is no problem even if a recycled PPS resin obtained by recycling PPS film waste or PPS fiber waste is used. Absent.

  PPS is usually obtained in powder form, but before being subjected to melt spinning, the powder PPS is heated to a temperature higher than the melting point with an extruder or the like, melted and kneaded, and then filtered with a filter if necessary. It can be removed, extruded into a gut shape, cooled, and then processed into a pellet by a method such as cutting. The PPS powder or PPS pellets are preferably subjected to spinning after being dried at about 100 to 180 ° C. for about 5 to 24 hours under a vacuum.

  Next, the flat cross-sectional PPS monofilament of the present invention is characterized by containing 0.5 to 5.0% by weight of a polyamide resin as a component other than the PPS resin.

  Here, the polyamide resins that can be used in the present invention are various polyamides obtained by ring-opening polymerization of various lactams, polycondensation of various diamines with various dicarboxylic acids and polycondensation of various aminocarboxylic acids, and these Copolyamides combining polycondensation and ring-opening polymerization, specifically, nylon 6, nylon 66, nylon 610, polytetramethylene adipamide, metaxylenediamine-adipic acid polycondensate, polyhexa And methylene dodecanamide, polyundecanamide, polylaurolactam) and a copolymer of nylon 6 and nylon 66 (hereinafter abbreviated as nylon 6/66), among which nylon 6 and nylon 66 are particularly preferred. Can be used.

  The flat cross-sectional PPS monofilament of the present invention is characterized by containing 0.5 to 5.0% by weight of a polyamide resin as a component other than the PPS resin, preferably 1.0 to 4.5% by weight, When the content is 1.2 to 2.5% by weight, a more preferable effect is exhibited.

  In the present invention, the purpose of including the polyamide resin in the PPS resin is to improve the impact resistance of the PPS. In addition to the improvement in wear resistance due to the cross-sectional shape of the flat cross-sectional PPS monofilament of the present invention, the polyamide resin is included. When the flat cross-section PPS monofilament of the present invention is applied as a constituent material for industrial fabrics, the frequency with which the monofilament is cracked or broken by the impact on the loom during weaving is greatly suppressed. A very favorable effect such as that leading to the creation of the image is created.

  Here, with a flat cross-sectional PPS monofilament having a polyamide resin content of less than 0.5% by weight, sufficient impact resistance cannot be obtained, and the frequency of occurrence of thread breakage or thread cracking during weaving is increased. This will lead to undesirable results.

  On the other hand, with a PPS monofilament with a polyamide resin content exceeding 5.0% by weight, although high impact resistance is obtained, the tensile strength is lowered, and the practical strength of the resulting industrial fabric is also lowered. In the melt spinning process, the melt polymer mainly composed of PPS resin spun from the nozzle nozzle becomes thick and stable immediately after spinning from the nozzle discharge hole. Since the discharge state of the molten polymer thus obtained cannot be obtained, it may lead to problems such as a large distortion in the cross-sectional shape of the flat cross-sectional PPS monofilament and an extremely large fineness unevenness in the length direction of the monofilament.

  The flat cross-sectional PPS monofilament of the present invention is characterized in that the tensile strength measured in accordance with the provisions of JIS 2003 L1013 is 2.0 cN / dtex or more, and the similarly measured hook strength is 3.0 cN / dtex or more.

  Here, when the tensile strength is less than 2.0 cN / dtex and the catching strength is less than 3.0 cN / dtex, the practical strength of the resulting industrial fabric is lowered, and the woven joints and warps and wefts of the industrial fabric intersect. This leads to an unfavorable situation such as thread breakage at the so-called knuckle portion.

  Furthermore, the flat cross-sectional PPS monofilament of the present invention is characterized in that its tensile elongation is 30% or more and 70% or less, preferably 35% to 65%, and more preferably 40% to 62%. In addition, it can be expected that the dimensional stability of the industrial fabric is improved and that the process passability during weaving becomes extremely good.

  Here, in a flat cross-section PPS monofilament having a tensile elongation of less than 30%, the elongation is low, so that the occurrence of yarn breakage increases due to impact at the time of weft driving, and the yarn cracking at the time of punching only increases. Alternatively, when the catching strength is measured, the catching strength variation tends to increase, resulting in a flat cross-sectional PPS monofilament lacking in quality stability.

  On the other hand, in flat cross-section PPS monofilaments with a high elongation exceeding 70%, there are few problems such as yarn breakage when using warp and yarn breakage when wefting, but in the case of an industrial fabric, The excessively high elongation appears as it is as a characteristic of industrial fabrics, which is not preferable because the fabric is very easy to stretch and the dimensional stability becomes insufficient.

  Further, in the flat cross-sectional PPS monofilament of the present invention, it is preferable that at least a pair of internal angles of each part facing the central portion of the cross section of the flat cross-sectional monofilament is in the range of 120 to 150 °, more preferably 125 to 145 °. In the case of 130-140 °, it can be expected that a more excellent effect is exhibited.

  Here, when any of the angles of the inner angle is out of the above range, since any of the corners has an acute shape, an undesirable result that the corners are easily worn when weaving the industrial fabric. Will be invited.

  Further, in the flat cross-sectional PPS monofilament of the present invention, it is desirable that the flatness expressed by L / Dmax is in the range of 1.15 to 10.0 from the length L of the long side and the Dmax. Furthermore, when it is set to 1.5 to 8.0, more preferably 1.8 to 5.0, expression of a further excellent effect can be expected.

  Here, when the flatness ratio of the flat cross-sectional PPS monofilament is less than 1.15, the difference between the long side and the short side is small, the yarn is easy to roll and twist is easily mixed when weaving the industrial fabric, and the industrial fabric is excellent. It tends to be difficult to obtain surface smoothness, which is not preferable.

  On the other hand, when the flatness ratio is extremely large exceeding 10.0, in the case of warp, the number of yarns that can be warped as warp within a certain width of the industrial fabric is greatly reduced. This leads to an undesirable result in that the strength in the warp direction of the industrial fabric is lowered. Also, when used for wefts, the flatness of the flat cross-sectional PPS monofilament becomes extremely large, so that wefts are likely to be twisted during weaving and, as a result, the surface smoothness required of the fabric is improved. Not only will this significantly decrease, but it will also lead to a decrease in productivity, such as spending a lot of time on the work to correct these twists. In addition, if wefts are driven in a state where twisting has occurred, extremely unfavorable results will be brought about, such as an increase in the frequency of yarn cracking at locations where twisting occurs in the flat cross-sectional PPS monofilament.

  Although there is no restriction | limiting in particular in the manufacturing method of the flat cross section PPS monofilament of this invention, Usually, the method described below is applied preferably.

  For example, a method using a PPS resin mixture in which a PPS resin and a polyamide resin, which are main constituent materials of the present invention, are preliminarily measured and mixed in a desired mixing ratio, and a polyamide resin that is premixed in a high concentration with a PPS resin. Prepared as a PPS resin composition master batch (hereinafter referred to as “MB”), and weighed the PPS resin and the PPS resin composition MB immediately before melt spinning so that the polyamide resin has the desired content. Examples of the method include mixing and adding to melt spinning, and it is particularly preferable to use the PPS resin and the PPS resin composition MB for melt spinning because of good handling.

  Next, using a PPS resin composition in which polyamide resin is appropriately mixed at a desired mixing ratio, after melt-kneading with a spinning machine such as an extruder, the molten PPS polymer is extruded from a spinneret nozzle provided at the tip of the spinning machine, and a known method The flat cross section PPS monofilament of the present invention can be efficiently produced by cooling, stretching and heat setting.

  More specifically, a PPS resin composition in which a PPS resin and a polyamide resin are appropriately adjusted to have a desired mixing ratio is supplied to a spinning machine such as an extruder type, and is 20 to 80 ° C. higher than the melting point of PPS. After melt-kneading at a temperature, the molten polymer extruded from a desired irregular cross-section die provided at the tip of the melt spinning machine is cooled and solidified in warm water at 60 to 95 ° C. via a measuring gear pump. Subsequently, the obtained undrawn yarn is introduced into a drawing bath or drawing atmosphere adjusted to a temperature equal to or higher than the glass transition temperature of PPS, and one-stage drawing or two-stage or more multi-stage drawing is performed.

  Here, the total draw ratio is preferably in the range of about 2.8 to 5.5 times. Further, in order to adjust the dry heat shrinkage rate, the breaking elongation at the time of fiber breakage, etc., after passing through the stretching step. It is desirable to perform heat setting of about 0.8 to 1.0 times in a temperature atmosphere of about 90 to 280 ° C. with respect to the drawn yarn.

  The flat cross-sectional PPS monofilament of the present invention thus obtained has various inorganic particles such as titanium oxide, silicon oxide, silicon nitride, clay, talc, kaolin and zirconic acid as long as the desired characteristics are not excluded. And crosslinked polymer particles, conventionally known antioxidants, sequestering agents, ion exchangers, anti-coloring agents, light-proofing agents, inclusion compounds, various colorants, waxes, silicone oils, various surfactants, various reinforcing agents Fibers, fluororesins, polyesters, polyolefins, polystyrenes and the like can be contained.

  The flat cross-sectional PPS monofilament of the present invention thus obtained exhibits an extremely stable process passing property without thread breakage or thread breakage even when used in the latest high-speed large-scale loom. Furthermore, the conventional flat cross-sectional PPS monofilament It is possible to achieve a flatter cross-sectional PPS monofilament that can simultaneously realize even more excellent surface smoothness than an industrial fabric using, and can be suitably used as a constituent material of an industrial fabric.

  Hereinafter, the flat cross-sectional PPS monofilament of the present invention will be described in more detail, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

The physical properties and the like of the flat cross-sectional PPS monofilament of the present invention described above and below are values measured by the following method.
(1) Tensile strength and tensile elongation of monofilament According to JIS2003 L1013 8.5, in a temperature / humidity adjustment chamber at 20 ° C. and 65% RH, “Tensilon” UTM-4-100 type tensile test manufactured by Orientec Co., Ltd. Using a machine, test length: 250 mm, tensile speed: 300 mm / min. Measure the strength when the sample is cut, calculate the strength (cN / dtex) by dividing the strength by the fineness, Is shown as an average of 10 measurements.

(2) Hatch strength of monofilament In accordance with JIS2003 L1013 8.7, in a temperature / humidity adjustment chamber at 20 ° C. and 65% RH, using “Tensilon” UTM-4-100 type tensile tester manufactured by Orientec Co., Ltd. Test length: 250 mm, tensile speed: 300 mm / min. Measure the strength when the sample is cut, calculate the strength (cN / dtex) by dividing the strength by the fineness, and measure it ten times. The average value was shown.
(3) The thinnest part Dmin, the thickest part Dmax, and the length L of the long side
A sample for observing a flat cross-sectional PPS monofilament cross-section was cut out from 3 m of the flat cross-sectional PPS monofilament in a direction perpendicular to the fiber axis direction of the monofilament at any five locations.

  This cross-sectional observation sample is observed with a digital microscope VHX-100F manufactured by KEYENCE, and using the measurement tool of this digital microscope, the thinnest portion Dmin portion located at both ends of the flat cross-sectional width direction of the flat cross-sectional PPS monofilament The average value was Dmin, and the portion where the thickness in the vicinity of the central portion in the length direction of the long side was the maximum was Dmax, and measurement was performed up to three digits after the decimal point.

Using the same cross-sectional observation sample as described above, the maximum length in the flat cross-sectional width direction was defined as the long side L, and measurements were made up to 3 digits after the decimal point.
(4) Yarn cracking durability test Ten flat cross-section PPS monofilament samples cut out to a length of 70 mm are bundled, fixed to a motor-driven shaft, and a stainless steel round bar with a diameter of 15 mmφ is installed at a location 50 mm away from the drive shaft. It fixes so that about 20 mm of the monofilament sample front-end | tip part on the opposite side to a sample fixed end may contact the said stainless steel round bar.

  The motor shaft with the flat cross section PPS monofilament sample fixed is rotated at 1200 rpm for 15 minutes, and the tip of the flat cross section PPS monofilament bundle sample is rotated and collided with a stainless steel round bar. The crack durability evaluation was carried out three times, and the thread crack durability was judged according to the following criteria.

            A: Three times of tests were conducted, and no cracking occurred in the flat cross-sectional PPS monofilament, and the yarn cracking durability was extremely excellent.

            ○: Three times of tests were conducted, and only a crack was generated in a flat cross-section PPS monofilament having an average number of less than 1 out of 10 and sufficient durability for use in industrial fabrics was obtained.

X: The test was performed three times, and thread breakage occurred in one or more flat cross-section PPS monofilaments out of 10 in average, resulting in poor thread breakage durability.
(5) Weaving evaluation A warp weaving evaluation or a weft driving evaluation was performed and judged according to the following criteria.
(A) Evaluation of warp weaving A flat canvas PPS monofilament was used for warp to produce a double woven papermaking dryer canvas. The condition of warp breakage per 100 m ^{2 of the} dryer canvas was confirmed and judged according to the following criteria.

  ○: There were no warp cracks in the knuckle where the warp and weft intersected.

X: At the knuckle portion where the warp and the weft intersect, there were one or more warp cracks.
(B) Evaluation of Weft Punching A flat canvas PPS monofilament was used as a weft to produce a double woven papermaking dryer canvas. When weaving this dryer canvas 5 m in the length direction, the yarn breakage condition at the time of weft driving was confirmed and judged according to the following criteria.

  ○: The thread breakage at the time of weft driving was less than once.

X: The yarn breakage occurred twice or more when the weft was driven.
(6) Abrasion resistance evaluation After the above-mentioned warp weaving evaluation and weft driving evaluation, the degree of wear of the yarn and the state of occurrence of scraps were confirmed and judged according to the following criteria.

  ○: There is no thread wear and there is no shaving.

X: Yarn wear was confirmed, and generation of scraps was observed.
[Example 1]
A mixture of PPS resin (E2080 manufactured by Toray Industries Inc., MFR = 90): 80% by weight and polyamide resin (T1021 manufactured by Toray Industries Inc.): 20% by weight is supplied to a twin-screw melt extruder, kneading temperature: 300 ° C., L / D : Melting and kneading under the conditions of 30 and screw rotation speed: 300 rpm, PPS resin composition MB was produced.

  Next, PPS resin: PPS resin composition MB is supplied to an extruder-type spinning machine at a weight ratio of 90:10, melt-kneaded at a spinning machine temperature of 330 ° C., and a molten polymer is discharged from a generally flat cross-section spinneret. After the extrusion, an undrawn yarn of the PPS resin composition immediately cooled and solidified in warm water at 80 ° C. was obtained.

  Subsequently, the above undrawn yarn was first stretched 3.5 times in warm water at 95 ° C., and further subjected to secondary stretching 1.2 times in a dry heat atmosphere at 130 ° C. to give a total draw ratio of 4.2. Then, heat setting was performed under a constant tension condition in a dry heat atmosphere of 190 ° C., Dmin: 0.206 mm, Dmax: 0.401 mm, long side L: 0.803 mm, angle of inner angle (∠A) 135 A flat cross-sectional PPS monofilament shown in FIG.

Table 1 shows the results of the obtained flat cross-sectional PPS monofilament such as tensile strength, tensile elongation, hook strength, yarn cracking durability test, weaving evaluation and wear resistance evaluation.
[Example 2 and Comparative Examples 1-2]
Using the same spinning process as in Example 1, a flat cross-section PPS monofilament having a polyamide content changed as shown in Table 1 was obtained. Dmin, Dmax, L, Dmin / Dmax, long side L, L / Dmax, ∠A, tensile strength, tensile elongation, hook strength, yarn cracking durability, weaving evaluation and abrasion resistance of the obtained flat cross-section PPS monofilament (Hereinafter, Dmin, Dmax, L, Dmin / Dmax, Long side L, L / Dmax, ∠A, Tensile strength, Tensile elongation, Hatch strength, Yarn cracking durability, Weaving evaluation and Abrasion resistance Table 1 and Table 2 show evaluation results such as “result”.
[Examples 3 to 4 and Comparative Examples 3 to 4]
A flat cross-section PPS monofilament having a Dmin / Dmax changed as shown in Table 1 was obtained by changing the substantially rectangular cross-section spinneret using the same spinning process as in Example 1. Each evaluation result is shown in Table 1 and Table 2.
[Examples 5-6 and Comparative Examples 5-6]
By using the same spinning process as in Example 1 and changing the total draw ratio, flat cross-sectional PPS monofilaments having changed tensile strength, tensile elongation, and hook strength as shown in Table 1 were obtained. Each evaluation result is shown in Table 1 and Table 2.
[Comparative Example 7]
By using the same spinning process as in Example 1 and changing the substantially rectangular cross-section spinneret, a flat cross-sectional PPS monofilament having a cross-sectional shape changed as shown in Table 2 was obtained. Each evaluation result is shown in Table 2.

  As is clear from the results in Table 1, the flat cross-sectional PPS monofilament of the present invention has excellent tensile strength, hook strength, yarn cracking durability, weaving property, and wear resistance. It can be seen that the flat cross-sectional PPS monofilament used for textile use can be used very suitably.

  On the other hand, as is clear from the results in Table 2, in the flat cross-sectional PPS monofilament that does not satisfy the provisions of the present invention, yarn breakage occurs in the weaving process of the industrial fabric, or the yarn breaks into the industrial fabric product after weaving. It has become unpreferable as a flat cross-sectional PPS monofilament for industrial textile use due to defects and the like.

  That is, in Comparative Example 1 in which the polyamide content is less than the content of the present invention, the yarn cracking durability test result is insufficient, while in Comparative Example 2 in which the polyamide content exceeds the content of the present invention, the yarn is Although the crack durability test result was good, when weaving industrial fabrics, thread breakage occurred due to the tensile strength of flat cross-section PPS monofilaments being too low. A problematic flat cross-section PPS monofilament was obtained.

  Furthermore, in Comparative Examples 3 to 4 in which Dmax / Dmin does not satisfy the provisions of the present invention and Comparative Example 7 in which the cross-sectional shape is outside the present invention, the characteristics excluding the cross-sectional shape satisfy the provisions of the present invention. As a result, it was confirmed that the cross-sectional shape had a great influence on the process passability during weaving of industrial fabrics, such as a lot of thread wear and scraping in the weaving evaluation.

  The flat cross-sectional PPS monofilament of the present invention has excellent strength characteristics and proper elongation characteristics, and can improve impact resistance by containing polyamide, and the cross-sectional shape of the PPS monofilament is a flat octagonal shape. It shows excellent wear resistance and extremely stable processability when weaving industrial fabrics, and the resulting industrial fabrics also have excellent surface smoothness. It can be said that it is extremely suitable as a constituent material of the woven fabric.

Dmin: thickness of the thinnest part of the short side
Dmax: thickness of the shortest thickest part
L: Length of long side
∠A, ∠A ': Examples of inner angles of a pair of corners facing the center of the cross section

Claims (6)

A PPS monofilament made of a thermoplastic resin composition mainly composed of a PPS resin containing 0.5 to 5.0% by weight of a polyamide resin as a component other than a polyphenylene sulfide resin, and having a cross section perpendicular to the fiber axis direction The shape is a flat octagonal shape, the internal angles of the corners facing the center of the cross section are the same, and when the short side thickness is D, Dmax that maximizes the thickness of the central part of the octagon, and both ends When Dmin has the minimum thickness, Dmax / Dmin is in the range of 1.2 to 8.0, the tensile strength measured according to JIS 2003 L1013 is 2.0 cN / dtex or more, and the tensile elongation is 30% or more and 70% or less, and the cross-sectional polyphenylene sulfide characterized by having a hook strength measured by the same method of 3.0 cN / dtex or more Roh filament. 2. The flat cross-sectional polyphenylene sulfide monofilament according to claim 1, wherein at least a pair of internal angles of corners facing the center of the cross section is in a range of 120 ° to 150 °. The flat cross-sectional polyphenylene sulfide monofilament according to claim 1 or 2, wherein the flatness expressed by L / Dmax is 1.15 to 10.00 from the length L of the long side and the Dmax. . An industrial fabric comprising the flat cross-sectional polyphenylene sulfide monofilament according to any one of claims 1 to 3 as at least a part of warp and / or weft. The industrial fabric according to claim 4, which is a papermaking fabric. The industrial fabric according to claim 5, which is a paper-making dryer canvas.

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