WO2021246270A1

WO2021246270A1 - Polyamide monofilament

Info

Publication number: WO2021246270A1
Application number: PCT/JP2021/020116
Authority: WO
Inventors: 鯨井実月; 山口純郎; 村田祥
Original assignee: 東レ株式会社
Priority date: 2020-06-02
Filing date: 2021-05-27
Publication date: 2021-12-09
Also published as: CN115427617A; CN115427617B; JPWO2021246270A1; EP4141153A1

Abstract

This polyamide monofilament is characterized by including at most one knot having a fiber diameter that is at least 135% of the diameter of the fiber and at most one filament having a fiber diameter that is at most 80% of the diameter of the fiber, wherein the knot and filament are present at a position of 200,000 m in the longitudinal direction of the fiber.　Provided is a polyamide monofilament which is suitable for obtaining a filter having excellent filtration performance due to the excellent opening uniformity of a gauze fabric, and has excellent fiber diameter uniformity due to a small number of knots and filaments.

Description

Polyamide monofilament

The present invention relates to a polyamide monofilament. More specifically, the present invention relates to a polyamide monofilament suitable for obtaining a filter having excellent filtration performance such as an automobile filter, a medical filter, and an acoustic filter. In particular, the present invention provides a polyamide monofilament having excellent mesh opening uniformity, suitable for obtaining a filter having good filtration performance, having few knots and fine threads, and having excellent fiber diameter uniformity.

Polyamide fiber is widely used for clothing and industrial materials because it has excellent mechanical properties, chemical resistance, and heat resistance. In industrial materials, it is widely used for filters using monofilament woven fabrics (screen gauze woven fabrics), and has a wide range of applications such as automobile filters, medical filters, and acoustic filters.

In the electronics field, which has continued to grow rapidly in recent years, and in the medical field, where extremely high quality is required, the demand for quality without clogging or opening is increasing. In particular, there is an increasing demand for knotting threads having fineness spots in the longitudinal direction and local fineness abnormalities, and many techniques have been proposed to improve the quality of these monofilaments.

For example, in Patent Document 1, a gelled polymer is mixed in the yarn as a factor of knotting, and this portion is not sufficiently stretched. The spinning pack is configured by providing a sintered filter made of short metal fibers and gelling. Techniques for sufficiently dispersing the compound have been reported.

In Patent Document 2, the core-sheath structure has a small number of nodes and a small number of nodes, including fine nodes that have become apparent, as opposed to the fineness of a monofilament having high strength, high modulus, and uniform fiber diameter in the longitudinal direction. Techniques for obtaining polyester monofilaments have been reported.

In Patent Document 3, the discharge hole 1 is formed by connecting the inflow hole 2, the measuring hole 3 having a cross-sectional area smaller than that of the inflow hole 2, and the relaxation hole 4 having a cross-sectional area larger than that of the measuring hole 3 in order. A melt-spinning die that can extend the cleaning cycle of the spinnery surface by high-speed spinning by using a spinneret, and a melt-spinning method using the same have been reported. By using this melt-spinning base and the melt-spinning method, the accumulation of dirt on the base surface can be further reduced and the discharge fluctuation can be reduced, so that the production of filaments with less yarn spots can be expected.

Japanese Unexamined Patent Publication No. 2014-231651 International Publication No. 2019/0444449 Japanese Unexamined Patent Publication No. 9-268417

However, in Patent Document 1, although it is effective as a technique for suppressing knotting, there is no mention of fine yarn, and it is insufficient as a technique for solving fine yarn. Until now, the methods for evaluating the quality of abnormal fineness have been the capture rate of the number of nodes by a slab catcher and the evaluation of fineness spots in the longitudinal direction (averaged) by a Wooster tester. There was a possibility that it would be a complaint. Further, in this conventional technique, there is a problem that fineness spots in the longitudinal direction are likely to occur due to destabilization of ejection of the mouthpiece.

Further, in Patent Document 2, in the polyester monofilament yarn having a core-sheath structure, a monofilament having less knotting yarn can be obtained, but in the production of the polyamide monofilament, the polyamide itself is easily thermally deteriorated and thermally decomposed, which causes knotting. This conventional technique is not sufficient for suppressing knotting and fine yarn of polyamide monofilament because it is easy to make a thermally deteriorated polymer and sublimates of low molecular weight materials (monomers, oligomers, etc.) are likely to be generated in comparison with polyester. be. Specifically, there has been a problem that knotted yarns and fine yarns are likely to be generated due to stains on the mouthpiece surface caused by sublimated products having a low molecular weight.

Further, in Patent Document 3, the upper limit of the diameter of the relaxation hole is as low as 0.75 mm, and the dirt accumulation density per unit circumference is high, so that there is a problem that knotting is likely to occur.

Therefore, the present invention is a polyamide monofilament for high-quality filters, which has uniform fineness spots and suppresses knots. The presence of knots leads to thread breakage and scum during warping and weaving. Further, when a monofilament having knots is woven, since the knots have a large diameter with respect to the fiber diameter, clogging occurs in a portion adjacent to the knots when the knots are formed, and the quality of the woven fabric is significantly deteriorated. In addition, the presence of fine yarns smaller than the normal fiber diameter has become apparent as the quality of filters has improved. The presence of fine yarns widens the opening of the fabric, allowing foreign matter to pass through and lead to poor filtration, so suppression of fine yarns is extremely important. The present invention provides a polyamide monofilament having excellent openness uniformity of a gauze fabric, few knots and fine threads suitable for obtaining a filter having good filtration performance, and excellent fiber diameter uniformity.

In order to achieve the above object, the present invention adopts the following configuration.
(1) Fine yarn having a fiber diameter of 135% or more with respect to the fiber diameter of 200,000 m in the fiber longitudinal direction is one or less, and the fiber diameter is 80% or less with respect to the fiber diameter. Polyamide monofilament characterized by one or less.
(2) The polyamide monofilament according to (1), wherein the CV% of the fiber diameter when measured at 200,000 m in the fiber longitudinal direction is 1% or less.
(3) No more than 10 nodes having a fiber diameter of 120% or more and less than 135% with respect to the fiber diameter existing in the fiber longitudinal direction of 200,000 m, and more than 80% and 90% or less with respect to the fiber diameter. The polyamide monofilament according to (1) or (2), wherein the number of fine threads having a diameter is 10 or less.
(4) The polyamide monofilament according to any one of (1) to (3), wherein the minimum value of the strong elongation product when measured 50 times continuously is 90% or more and 100% or less of the average value.
(5) The polyamide monofilament according to any one of (1) to (4), which has a fineness of 6 to 50 dtex.

According to the present invention, it is possible to provide a polyamide monofilament having excellent mesh opening uniformity of a gauze fabric, suitable for obtaining a filter having good filtration performance, few knots and fine threads, and excellent fiber diameter uniformity.

It is a vertical cross-sectional view which shows an example of the discharge hole in the melt spinning mouthpiece used in the manufacture of the polyamide monofilament of this invention. It is a process schematic diagram which shows an example of the manufacturing method of the polyamide monofilament of this invention. It is a vertical cross-sectional view which shows an example of the spinning pack used for the melt spinning of the polyamide monofilament of this invention.

Hereinafter, the implementation of the present invention will be described in detail.

The node in the present invention is a knob-shaped local fiber diameter abnormality existing in the fiber longitudinal direction, and means a thick fiber diameter of 120% or more with respect to the standard fiber diameter. The fine thread means a fine fiber diameter of 90% or less with respect to the standard fiber diameter. Knots and fine threads are measured with an optical external shape detection device (PSD-200 manufactured by Sensotropic) at a traveling speed of 800 m / min, a thread length interval of 0.07 mm, and a thread length of 200,000 m. In the optical external shape detection device, the fiber diameter, the standard deviation of the fiber diameter, the number and size of knots, and the number and size of fine threads are recorded as numerical values.

The polyamide monofilament of the present invention has one or less nodes having a fiber diameter of 135% or more with respect to the fiber diameter, which exists in the fiber longitudinal direction of 200,000 m, and has a fiber diameter of 80% or less with respect to the fiber diameter. There is one or less fine threads. By setting the range of knots and fine threads, a filter having good uniformity of monofilament, excellent uniformity of opening of the gauze fabric, and good filtration performance can be obtained. If there is more than one knot with a fiber diameter of 135% or more of the fiber diameter, opening or clogging will occur in the portion adjacent to the knot when the fabric is made of gauze, and the uniformity of opening will decrease. .. In addition, during high-order processing, it gets caught in the reed, and thread breakage and scum increase. When the number of fine threads having a fiber diameter of 80% or less with respect to the fiber diameter exceeds one, the mesh fabric is opened and the opening uniformity is lowered. If the gauze fabric is opened, foreign matter will pass through it when it is used as a filter, and the filtration performance will deteriorate.

The polyamide monofilament of the present invention has 10 or less nodes having a fiber diameter of 120% or more and less than 135% with respect to the fiber diameter, existing in 200,000 m in the fiber longitudinal direction, and has more than 80% and 90% with respect to the fiber diameter. It is preferable that the number of fine yarns having a fiber diameter of% or less is 10 or less. By setting the number of knots having a fiber diameter of 120% or more and less than 135% with respect to the fiber diameter to 10 or less, it is possible to suppress the defect of clogging of the gauze fabric, and the uniformity of the opening of the gauze fabric is further improved. However, it is possible to improve the filtration performance of the filter. Further, by reducing the number of fine yarns having a fiber diameter of more than 80% and 90% or less with respect to the fiber diameter to 10 or less, it is possible to suppress the defect of opening the gauze fabric, and similarly, the opening of the gauze fabric. The uniformity is further improved, and the filtration performance of the filter can be improved. More preferably, there are 5 or less nodes having a fiber diameter of 120% or more and less than 135% with respect to the fiber diameter existing in the fiber longitudinal direction of 200,000 m, and 80% or more and 90% or less with respect to the fiber diameter. The number of fine threads having a fiber diameter is 5 or less.

The polyamide monofilament of the present invention preferably has a CV% of fiber diameter of 1.0% or less when measured at 200,000 m in the fiber longitudinal direction. The CV% of the fiber diameter can be calculated by the percentage obtained by dividing the standard deviation of the fiber diameter by the average value of the fiber diameter, and indicates the degree of fineness unevenness in the longitudinal direction. The lower the value, the better the uniformity of the fiber diameter. Is shown. By setting the CV% to 1.0% or less, a monofilament having no fineness unevenness in the fiber longitudinal direction and having excellent fiber diameter uniformity can be obtained. In addition, a filter having excellent opening uniformity of the gauze fabric and good filtration performance can be obtained. A more preferable CV% of the fiber diameter is 0.8% or less.

In the polyamide monofilament of the present invention, it is preferable that the minimum value of the strong elongation product when measured 50 times continuously is 90% or more and 100% or less of the average value. If there are knots or fine threads, the points become break points and tend to become weak threads, which tends to locally reduce the durability of the gauze fabric. When it is 90% or more, the durability of the gauze fabric and the durability of the filter are improved.

The polyamide monofilament of the present invention preferably has a fineness of 6 to 50 dtex for high mesh filter applications. More preferably, it is 8 to 47 dtex. In particular, for high-definition high-mesh filter applications, the fineness is preferably 6 to 13 dtex. Further, as will be described later, in the production of the polyamide monofilament of the present invention, by setting the value to 50 dtex or less, it is possible to obtain a polyamide monofilament having excellent filtration performance without knots or fine threads by suppressing cooling spots even in a cooling facility by air cooling. You can. Further, by setting the value to 6 dtex or more, it is possible to obtain a polyamide monofilament having excellent filtration performance without knots or fine threads by suppressing discharge fluctuations.

The polyamide monofilament of the present invention preferably has a strength of 4.0 cN / dtex or more and an elongation of 30 to 60%. Within such a range, the durability of the gauze fabric can be guaranteed.

The manufacturing method for obtaining the polyamide monofilament of the present invention is shown below.

The polyamide referred to in the present invention is a high-molecular-weight body in which a so-called hydrocarbon group is linked to the main chain via an amide bond, and is preferably polycapro because of its excellent dyeability, wash fastness, and mechanical properties. It is a polyamide composed of an amide or a polyhexamethylene adipamide. The term "mainly" as used herein is a polyamide containing mainly ε-caprolactam units constituting the polycaprolamide and mainly containing the polyhexamethylenediaminediammonium adipade unit, and these units are contained in an amount of 80 mol% or more. It is preferable to use 90 mol% or more. The other components are not particularly limited, but are, for example, polydodecanoamide, polyhexamethylene azelamide, polyhexamethylene sebacamide, polyhexamethylene dodecanomid, polymethoxylen adipamide, and polyhexamethylene terephthalamide. , Aminocarboxylic acid, dicarboxylic acid and other units which are monomers constituting polyhexamethylene isophthalamide and the like.

The degree of polymerization of the polyamide may be appropriately selected from the range common sense for producing industrial fibers, but is preferably in the range of 2.0 to 3.3 with a relative viscosity of 98% sulfuric acid, and more preferably 2. The range of 4 to 3.3 is preferable. Within such a range, it becomes possible to obtain a polyamide monofilament having the strength required for a gauze fabric with good silk-reeling properties.

In the production of the polyamide monofilament of the present invention, it is preferable to adjust the moisture content of the polyamide resin chip used for spinning to 0.11 to 0.15% by drying or the like. Within this range, it becomes possible to suppress the knots and fine threads of the polyamide monofilament. The water content referred to here is a value measured by putting a polyamide resin chip sample into a trace moisture meter, vaporizing the moisture at 230 ° C. for 30 minutes, and reading the moisture value.

The melt spinning temperature of the polyamide resin chip is preferably a temperature exceeding the melting point of the polyamide resin, that is, melting at a melting point of plus 20 to 40 ° C. Within this range, it becomes possible to suppress the knots and fine threads of the polyamide monofilament.

In the method for producing a polyamide monofilament of the present invention, the basic production process may be a known technique, for example, a method of continuously performing a spinning-drawing step (direct spinning and drawing method), or once winding an undrawn yarn. It is obtained by a method of stretching later (two-step method).

An example of the method for producing a polyamide monofilament of the present invention will be described with reference to the process schematic diagram of FIG. First, the polyamide resin chips melted by the extruder are applied to the melt spinning pack 10, and the spun yarns are discharged from the spinning spouts 11 having round holes in which two discharge holes are arranged in a circumferential shape. Next, the yarns are cooled by a uniflow type chimney 12 that is blown from one direction, the yarns are divided into yarns one by one, a spinning oil is applied by a refueling guide 13, and then the yarns are picked up by a first gode roller 14. It is stretched between the second god roller 15 and the third god roller 16, heat-treated by the third and fourth god rollers (16, 17), and wound by the winding device 18.

The melt spinning pack used in the production of the polyamide monofilament of the present invention is a melt spinning pack in which at least a spinneret, a pressure plate, a metal wire filter, and a sand filter medium layer or a rectifying plate are arranged, and is a metal wire filter and a sand filter medium layer or. The melt-spun pack described in Patent Document 1 provided with a sintered filter made of short metal fibers having a substantially polygonal cross section between the rectifying plate and the rectifying plate is used.

As the main cause of the nodes generated in the polyamide monofilament, a gelled polymer that was heat-modified due to the variation in the viscosity of the polyamide molten polymer was generated, and the polymer was not completely melted and a gel-like substance was mixed into the thread from the mouthpiece hole. It is considered that this is because the threads are ejected in this state and this portion is not sufficiently stretched. In order to improve the knots, it is necessary to disperse this gel-like substance. In order to disperse the gel-like material, the filtration accuracy of the metal wire filter, sand filter medium layer or rectifying plate constituting the molten spinning pack is improved, and the metal short fibers having a substantially polygonal shape are used to make the metal short fibers mutual. This is because entanglement occurs and the filterability and dispersibility are further improved. The substantially polygonal shape is preferably a shape having an acute-angled cross-sectional shape. This is because the heat-denatured gelled polymer can be finely dispersed by colliding with the acute-angled portion of the cross section, and the heat-denatured gelled polymer can be further subdivided by forming the acute-angled cross-sectional shape. be.

The spinneret used in the production of the polyamide monofilament of the present invention is formed by connecting a polymer inflow hole, a measuring hole having a cross-sectional area smaller than the inflow hole, and a relaxation hole having a cross-sectional area larger than the measuring hole in order. Use the existing melt spinning mouthpiece.

In melt spinning of polyamide, low molecular weight polymers (monomers, oligomers, etc.) discharged from the spinneret sublimate and accumulate as dirt around the polymer discharge holes over time. In general, a mold release material such as silicone is applied to the polymer discharge side surface of the melt spinning spout in order to improve the mold release property of the polymer. However, as described above, dirt accumulation around the polymer discharge hole and polymer release are performed. Due to the deterioration of the performance, the ejection state of the polymer from the spinneret becomes unstable, yarn spots in the yarn longitudinal direction occur, knots and fine yarns are generated, and further, yarn breakage is induced. As a countermeasure, in Patent Document 3 (Japanese Unexamined Patent Publication No. 9-268417), the ratio (D2 / D1) of the measuring hole diameter (D1) to the relaxation hole diameter (D2) is 1.75 to 2.5, and the relaxation hole diameter (D2). Is 0.40 to 0.75 mm, and it is clearly stated that a molten spinneret for high-speed spinning that can be taken up at a high speed of 2000 m / min or more, which can extend the cleaning cycle of the mouthpiece surface by suppressing fineness spots by stabilizing discharge and reducing yarn breakage, is provided. is doing. Further, although it is effective up to a single yarn fineness of 8 denier (9 dtex), even if it is applied to the production of a polyamide monofilament to be taken up at a single yarn fineness of 6 dtex or more and 1000 m / min or less, the discharge state of the polymer becomes unstable over time. , There were thread spots such as knots and fine threads.

FIG. 1 shows an example of a discharge hole provided in the spinneret used in the present invention. In FIG. 1, the discharge hole 1 is formed so that the inflow hole 2, the measuring hole 3, and the relaxation hole 4 are continuous in this order along the flow direction of the molten polymer. In the configuration of the discharge hole 1, the measuring hole 3 has a smaller cross-sectional area than the inflow hole 2 and measures the molten polymer that has flowed in from the inflow hole 2. The relaxation hole 4 following the measurement hole 3 reduces the accumulation density of dirt per unit circumference around the polymer discharge hole by expanding the cross-sectional area as compared with the measurement hole 3, and also has the effect of reducing the ballast by relaxing the pressure of the molten polymer. Can be demonstrated.

In the spinneret used in the production of the present invention, the back pressure of the discharge hole tends to decrease by making the relaxation hole diameter (D2) larger than the measuring hole diameter (D1) as described above. It is necessary to reduce the measuring hole diameter (D1) as much as the back pressure decrease. On the other hand, if the measuring hole diameter (D1) is small, it is difficult to uniformly fill the entire discharge hole with the molten polymer, and the discharge becomes unstable. The measuring hole diameter (D1) is preferably designed so that the ratio (L1 / D1) to the measuring hole length (L1) is 2.0 to 3.5. Within such a range, it is possible to stabilize the discharge of the molten polymer while ensuring the back pressure and the measurable property, and it is possible to obtain a polyamide monofilament having few knots and fine threads and having excellent fiber diameter uniformity. More preferably, it is 2.5 to 3.0.

In the spinneret used in the production of the present invention, the ratio (D2 / D1) of the measuring hole diameter (D1) to the relaxation hole diameter (D2) is preferably 2.6 to 4.0. By setting this range, the molten polymer has a large cross-sectional area in the relaxation hole having a diameter larger than that of the measuring hole, so that the pressure of the molten polymer squeezed by the measuring hole is relaxed and the dirt around the discharge hole is removed. It is possible to suppress thread picking and reduce discharge fluctuations. In addition, it reduces the shear rate and stress of the molten polymer, suppresses the generation of frictional heat, and suppresses stains. Further, since the peripheral length is larger than the polymer discharge amount due to the larger relaxation hole diameter, the accumulation density of dirt per unit peripheral length can be reduced. Therefore, a polyamide monofilament having stable ejection of the molten polymer and good fiber diameter uniformity can be obtained. More preferably, it is 3.0 to 3.7.

In the spinneret used in the production of the present invention, the relaxation hole diameter (D2) is 0.8 to 1.4 mm. By setting the relaxation hole diameter (D2) in this way, the discharge of the molten polymer is stable, and the polymer bending and picking due to dirt around the discharge hole can be suppressed. By improving the discharge stability, it is possible to suppress the generation of knots and fine threads due to poor discharge, and it is possible to obtain a polyamide monofilament having excellent filtration performance. When the relaxation hole diameter (D2) is less than 0.8 mm, the accumulation density of dirt per unit circumference becomes large, so that polymer bending and picking due to dirt around the discharge hole are likely to occur. In addition, since the action of relaxing the pressure of the molten polymer is also reduced, the shear rate of the molten polymer is increased, the area around the discharge hole is contaminated by frictional heat, and the discharge stability is lowered. When the relaxation hole diameter (D2) is 1.4 mm or more, it is difficult to uniformly fill the entire discharge hole (particularly in the relaxation hole), the discharge state is liable to fluctuate, and only knots and fine threads are generated. There are also many spinning yarn breaks. More preferably, it is 1.0 to 1.2 mm.

Further, if the relaxation hole 4 is increased, the polymer rate (slip rate) discharged from the polymer discharge hole decreases, so it is preferable to optimize the spinning speed. When the spinning speed is increased, the larger the difference between the slipping speed and the spinning speed, the more irregular crystal orientation progresses, and knots and fine yarns are more likely to occur. Therefore, in the method for producing a polyamide monofilament of the present invention, the spinning speed is 300 to 1000 m / min, preferably 300 to 600 m / min in the case of two steps, and 300 to 800 m / min in the case of one step. Within this range, a polyamide monofilament having few knots and fine threads and excellent fiber diameter uniformity can be obtained.

Hereinafter, the present invention will be described in more detail by way of examples. The physical property values in the examples were measured by the method described below.

A. Number of knots and fine threads (1) Place one package on the creel.
(2) The thread is unwound at a speed of 800 m / min and passed through an optical inspection device (PSD-200 manufactured by Sensotropic).
(3) The fiber diameter is measured at intervals of 0.07 m in yarn length. The measurement is carried out for 250 minutes.
(4) A node having a fiber diameter of 135% or more with respect to the fiber diameter One node was set for each measured value in which the fiber diameter was increased by 35% or more (fiber diameter of 135% or more) with respect to the standard fiber diameter.
(5) A node having a fiber diameter of 120% or more and less than 135% with respect to the fiber diameter. Therefore, one section was used.
(6) Fine yarn having a fiber diameter of 80% or less with respect to the fiber diameter One fine yarn was used for each measured value reduced by 20% or more (fiber diameter less than 80%) with respect to the standard fiber diameter. ..
(7) Fine yarn having a fiber diameter of more than 80% and 90% or less with respect to the fiber diameter Measured with a decrease of 10% or more and less than 20% (fiber diameter of more than 80% and 90% or less) with respect to the standard fiber diameter. One fine thread was used for each value.

B. CV% of fiber diameter
(1) Place one package on the creel.
(2) The thread is unwound at a speed of 800 m / min and passed through an optical inspection device (PSD-200 manufactured by Sensotropic).
(3) The fiber diameter is measured at intervals of 0.07 m in yarn length. The measurement is carried out for 250 minutes.
(4) The standard deviation of the fiber diameter and the average value of the fiber diameter were read, and the CV% of the fiber diameter was calculated by the following formula.
CV% of fiber diameter = (standard deviation of fiber diameter) / (average value of fiber diameter) × 100.

C. Strength, Elongation, Strong Elongation Product Fiber sample is "Tencilon" (registered trademark) manufactured by Orientec Co., Ltd., according to JIS L1013 (2010), constant speed elongation condition, grip interval 50 cm, tensile speed 50 cm / It was measured 50 times in minutes. The strength was obtained from the point showing the maximum strength in the tensile strength-elongation curve, and the elongation was obtained from the elongation showing the maximum strength. The strength was defined as the value obtained by dividing the maximum strength by the total fineness. The strong elongation product was calculated by the following formula, and the minimum value and the average value of the individual values of 50 measurements were calculated.
Strong elongation product = strength [cN / dtex] × (1 + elongation [%] / 100).

D. Aperture volatility The polyamide monofilament was warped to 20 lines / mm with a warping machine, and weaved to 20 lines / mm (so that the opening was square) with a rapier loom. This trial weaving fabric was observed with a scanning electron microscope (ESEM-2700 manufactured by Nikon) at a magnification of 1000 times, and the interfiber distance of each opening at any 20 locations (the widest part of each opening) was observed. Each measurement) was measured on the order of 0.1 μm. The aperture volatility was calculated by the following equation.
Aperture volatility (%) = (standard deviation of interfiber distance) / (average value of interfiber distance) × 100
As for the aperture volatility, 3% or less, which is an index of a highly precise filter, was accepted.

[Example 1]
The melt spinning pack shown in FIG. 3, which is composed of a spinneret 30, a pressure plate 27, a metal wire filter 26, a sintered filter 25, and a sand filter medium 24, was used. The spinneret 30 has an inflow of a measuring hole diameter φ (D1) 0.30 mm, a measuring hole length (L1) 0.75 mm, a relaxation hole diameter φ (D2) 1.0 mm, and a measuring hole length (L2) 1.0 mm as shown in FIG. It is a discharge hole having a hole 2, a measuring hole 3, and a relaxation hole 4, and has four discharge holes. The sintered filter 25 is a sintered filter (thickness 2 mm) made of short stainless steel fibers having a substantially polygonal cross section, a length of 1.0 to 3.0 mm, a converted diameter of 30 to 60 μm, and an aspect ratio of 10 to 100. , Filtration accuracy 40 μm).

Nylon 66 chips with 98% sulfuric acid relative viscosity of 2.8 are dried, the moisture content is adjusted to 0.13%, and then melted at a melting temperature of 290 ° C., and the polymer discharge rate per molten spinning pack is 6.5 g. The discharge amount was adjusted so as to be / minute, and the yarn was subjected to a melt spinning pack, and the spun yarn was discharged from a round-hole spinneret having two discharge holes arranged in a circumferential shape. Then, by the heating means provided to the base downstream side, heated the heating gas flow path (not shown), 130 ° C. The steam to die, after supplying an amount of the base area of 1 cm ² per 150 mg / min, single The yarns are cooled by a uniflow type chimney that blows from the direction, the yarns are divided into one yarn, and the spinning oil is applied with a refueling guide so that the adhesion amount is 0.5%, and then the spinning speed is 500 m. The thread was wound at / minute. The undrawn yarn was drawn 4.3 times with a drawing machine to obtain a nylon 66 monofilament.

The obtained nylon 66 monofilament was evaluated for the number of nodes, fineness spots, strength product, and aperture ratio of the filter. The results are shown in Table 1.

[Examples 2 to 6, Comparative Examples 1 to 2]
Spinning in the same manner as in Example 1 except that the measuring hole diameter (D1) 7, the measuring hole length (L1) 6, the relaxation hole diameter (D2) 9, and the relaxation hole length (L2) 8 shown in FIG. 1 were changed as shown in Table 1. , Stretching was performed to obtain a nylon 66 monofilament. The results are shown in Table 1.

[Example 7]
Nylon 66 monofilament was obtained by spinning and stretching in the same manner as in Example 1 except that the spinning speed was changed as shown in Table 2. The results are shown in Table 2.

[Example 8]
Using a spinneret having two discharge holes, adjust the discharge amount so that the polymer discharge amount per melt spinning pack is 15 g / min, and measure the measuring hole diameter (D1) 7 shown in FIG. Nylon 66 monofilament was obtained by spinning and stretching in the same manner as in Example 1 except that the hole length (L1) 6, the relaxation hole diameter (D2) 9, and the relaxation hole length (L2) 8 were changed as shown in Table 2. The results are shown in Table 2.

[Example 9]
Using the spinning device shown in FIG. 2, the first Gode roller 14 takes over at a spinning speed of 760 m / min, stretches 4.1 times between the second Gode roller 15 and the third Gode roller 16, and the third and fourth Gode rollers (16). , 17) was heat-treated at 170 ° C., and the same procedure as in Example 1 was carried out except that the winding device 18 was used for winding at 3000 m / min to obtain a nylon 66 monofilament. The results are shown in Table 2.

[Comparative Example 3]
It is a discharge hole composed of only the inflow hole 2 and the measuring hole 3, and spinning and stretching are performed in the same manner as in the first embodiment except that the measuring hole diameter (D1) and the measuring hole length (L1) are changed as shown in Table 2. This was done to obtain a nylon 66 monofilament. The results are shown in Table 2.

1: Discharge hole 2: Inflow hole 3: Measuring hole 4: Relaxing hole 5: Inflow hole diameter 6: Measuring hole length (L1)
7: Measuring hole diameter (D1)
8: Relaxation hole length (L2)
9: Relaxation hole diameter (D2)
10: Molten spinning pack 11: Molten spinneret 12: Chimney 13: Refueling guide 14: 1st Gode roller 15: 2nd Gode roller 16: 3rd Gode roller 17: 4th Gode roller 18: Winding device 19: Polymer introduction part 20: Upper part Pack block 21: Intermediate pack block 22: Lower pack block 23: Protruding step 24: Sand filter medium 25: Sintered filter 26: Metal wire filter 27: Pressure plate 28: Polymer passage hole 29: Packing 30: Spinner 31: Discharge Hole

Claims

One or less knots having a fiber diameter of 135% or more with respect to the fiber diameter and one or less fine yarn having a fiber diameter of 80% or less with respect to the fiber diameter existing in the fiber longitudinal direction of 200,000 m. Polyamide monofilament characterized by being.
The polyamide monofilament according to claim 1, wherein the CV% of the fiber diameter when measured at 200,000 m in the fiber longitudinal direction is 1% or less.
There are 10 or less nodes having a fiber diameter of 120% or more and less than 135% with respect to the fiber diameter existing at 200,000 m in the fiber longitudinal direction, and the fiber diameter is more than 80% and 90% or less with respect to the fiber diameter. The polyamide monofilament according to claim 1 or 2, wherein the number of fine threads is 10 or less.
The polyamide monofilament according to any one of claims 1 to 3, wherein the minimum value of the strong elongation product when measured 50 times continuously is 90% or more and 100% or less of the average value.
The polyamide monofilament according to any one of claims 1 to 4, wherein the fineness is 6 to 50 dtex.