JP2011058144A - Polyamide monofilament and industrial woven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polyamide monofilament which can preferably be used as a constituent material for industrial woven fabrics, and industrial woven fabrics using the monofilament, the polyamide monofilament containing MXD6 as its constituent material being made to have improved property of heat resistance, while further achieving an excellent wire diameter accuracy, a high degree of bending durability, and excellent flexural rigidity. <P>SOLUTION: The polyamide monofilament includes a polyamide composition containing: a diamine component with meta-xylylene diamine as a main constituent; polyamide A obtained by polycondensation reaction of a dicarboxylic acid constituent with adipic acid as a main component; and other polyamide B, where the sulfuric acid relative viscosity difference between polyamide A and polyamide B is 1.2 or less, the monofilament including 0.01 to 5 pts.wt. of phenolic antioxidant to the total of 100 pts.wt. of 90 to 55 wt.% of polyamide A and 10 to 45 wt.% of polyamide B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a polyamide monofilament useful as an industrial fabric material having excellent heat resistance and wire diameter accuracy, and also having excellent bending durability, and an industrial fabric using at least a part of this polyamide monofilament In particular, it relates to a papermaking fabric.

  Polyamide monofilaments are widely used as materials for various industrial fabrics, such as paper fabrics such as papermaking wires and dryer canvases, belt fabrics such as conveyor belts and dewatering belts, and filter fabrics such as filters for various belt presses. Yes.

  In addition, when these industrial fabrics are actually used, all of them are in contact with the driving rolls and control rolls that are running and receive wear. Abrasion is required.

  For example, in the papermaking industry, acid paper has been mainly produced in the past. However, as the problem of deterioration of paper over time has become more prominent, conversion to neutral paper has become active. With this conversion from acidic paper to neutral paper, the filler for paper called filler has been changed from talc to calcium carbonate, but the calcium carbonate particles are harder than talc particles, so in the papermaking process The paper making wire used has a fast wear, and the woven fabric made of polyester monofilament, which has been generally used for this purpose, has a short life.

  Therefore, improvement of the wear life of industrial fabrics has been achieved by interweaving polyester monofilaments and polyamide monofilaments such as nylon 6 which are more excellent in wear resistance.

  Here, in a general papermaking fabric, the fabric warp on the running surface has been a problem for improving the wear resistance from the viewpoint of the stability of the fabric in use and the extension of the service life. That is, when the warp is worn, the dimensional change of the fabric occurs, and when the warp is worn and cut, the fabric itself is directly cut, so that the life of the fabric is shortened.

  Therefore, in order to improve such abrasion resistance, warp yarns are not worn by using polyester monofilaments for warps and interweaving using polyamide monofilaments with excellent abrasion resistance for all or part of the wefts. He was devised.

  Furthermore, in the recent papermaking industry, the speed of papermaking has been increasing, but with the aim of improving energy loss during the operation of the papermaking machine due to such high speeding of the papermaking speed, the papermaking machine can be operated by reducing the weight of the papermaking fabric. From this background, fiber products that are used as constituent materials as a means of reducing the weight of fabrics are also used for textile products represented by various monofilaments used in papermaking fabrics. It has been demanded to reduce the diameter.

  Depending on the actual situation, polyamide monofilaments, which are the constituent materials of papermaking fabrics used in these high-speed papermaking, have come to use monofilaments with a smaller diameter than before, but polyamide monofilaments are made of resin materials. Although it is rich in wear resistance as a characteristic, it has the characteristic that it is flexible on the other hand. Compared to polyester monofilaments, it has dimensional stability, fabric rigidity, and the so-called knuckle section where the warp and weft of the fabric intersect. When using thin polyamide monofilaments, the rigidity against bending of the monofilaments is particularly insufficient, so there are cases in which the use of the monofilaments may be discouraged. .

  Furthermore, polyamide monofilaments are inferior in heat resistance to polyester monofilaments, so that not only has the problem that the yarn quality deteriorates due to heat during heat setting after weaving the fabric, but the polyamide resin becomes brittle due to heat. As a result, the wear resistance deteriorates and the durability life is shortened, and the monofilament breaks down due to the effect of heat and the air permeability is lowered, so that the function as a fabric is reduced. Therefore, there has been a strong demand for the development of small-diameter polyamide monofilaments that can be used in paper fabrics that can withstand temperatures, have superior bending rigidity than conventional polyamide monofilaments, and also have high heat resistance.

  In order to solve the above-described problems, various proposals have been conventionally made.

  For example, in order to improve the heat resistance of polyamide monofilament, nylon 66 is mixed and spun at a ratio of 75 to 85% by weight of nylon 66 and 15 to 25% by weight of nylon 6 in a heat resistant round cross-section monofilament, and immediately cooled in a liquid. At this time, a method of adding at least 30 ppm of Cu to nylon 66 to make it heat resistant has been proposed (for example, see Patent Document 1). However, the heat resistance of the polyamide monofilament obtained by this technique exhibits a corresponding effect. However, due to the addition of Cu, there were problems such that the polyamide monofilament turned blue and black over time due to the influence of copper ions, and that yarn breakage occurred during spinning due to the influence of Cu.

  A film or monofilament obtained from a polyamide resin composition containing a total amount of 0.005 to 1 part by weight of a hydroxyphenylpropionic acid ester and a cyclic phosphite having a hydroxy group with respect to 100 parts by weight of the polyamide resin (See, for example, Patent Document 2). However, although this technology is related to the heat resistance improvement of monofilaments composed of a polyamide resin composition, the purpose is to improve the thermal stability of the polyamide resin composition during melt spinning, and The products obtained by the technology are intended to have heat resistance in hot water or water vapor, and therefore have a heat resistance performance at a high temperature exceeding 160 ° C., which is the heat setting temperature in the manufacturing process of papermaking fabrics. From a point of view, it was still insufficient.

  Further, as a technique for improving the heat resistance of polyamide monofilament, hindered phenol is used for 100 parts by weight of nylon 6/66 copolymer comprising caproamide unit (nylon 6 unit) and hexamethylene adipamide unit (nylon 66 unit). A polyamide monofilament (see, for example, Patent Document 3) having improved heat resistance and wear resistance, comprising a composition to which 0.05 to 1 part by weight of a compound and 0.1 to 0.5 part by weight of a bisamide compound are added. Proposed. However, according to this technology, it is possible to realize a polyamide monofilament excellent in heat resistance, but as a polyamide monofilament for use in a papermaking fabric used in a high-speed paper machine, the constituent material is a nylon 6/66 copolymer. For this reason, since only a woven fabric that is too flexible and lacks rigidity can be obtained, the actual situation is that it is insufficient as a polyamide monofilament having excellent bending rigidity.

  On the other hand, as a technology of a polyamide filament that improves the bending rigidity while utilizing the wear resistance performance of the polyamide resin, the crystalline polyamide (A) obtained from the polycondensation reaction of metaxylenediamine and adipic acid is 5 to 50 weights. % And other polyamide (B) 95-50% by weight, a filament made of a polyamide resin composition, and heat shrinkage stress decreases in the temperature drop region at 80 ° C. or lower after heating in a constant length state There has been proposed a polyamide resin filament for industrial textiles (see, for example, Patent Document 4). The polyamide filaments obtained with this technology are superior to the conventional polyamide filaments in terms of flexural rigidity. However, the heat resistance required for papermaking fabrics is completely considered. In addition, it has not yet been sufficient as a technique for realizing a filament having excellent wire diameter accuracy that affects the surface smoothness of industrial fabrics.

Japanese Patent Publication No. 2001-518152 JP 2002-121380 A JP 2002-69748 A JP 2006-144144 A

  In view of the above situation, the present invention has been achieved as a result of studying the solution of problems in the prior art as an object. The object of the present invention is to improve the heat resistance of polyamide monofilament, Even when subjected to heat history under dry heat conditions, the strength decrease due to thermal deterioration is extremely small, and by realizing excellent wire diameter accuracy and bending durability performance, it can be suitably used as a constituent material for industrial fabrics. An object of the present invention is to provide a polyamide monofilament having a bending rigidity superior to a conventional polyamide monofilament and an industrial fabric using the same.

  To achieve the above object, the present invention comprises a diamine component mainly composed of metaxylylenediamine and a polyamide A obtained by polycondensation reaction of a dicarboxylic acid component mainly composed of adipic acid and other polyamides B. The difference in sulfuric acid relative viscosity between the polyamide A and the polyamide B is within 1.2, and the phenolic oxidation is performed with respect to 100 parts by weight of the polyamide A 90 to 55% by weight and the polyamide B 10 to 45% by weight. A polyamide monofilament comprising a polyamide composition containing 0.01 to 5 parts by weight of an inhibitor, the polyamide monofilament having an untreated polyamide monofilament when treated for 4 hours in a dry heat atmosphere at 180 ° C. More than 70% of monofilament strength, monofilament flatness measured in the fiber axis direction 10% or less in diameter variation rate relative to the diameter, the bending fatigue breaking number more than 5000 times, the polyamide monofilaments are provided the number of times bending abrasion fracture is characterized by satisfying 10,000 times or more properties simultaneously.

  Here, in the polyamide monofilament of the present invention, it is preferable that the polyamide B is at least one selected from nylon 6, nylon 66, nylon 610, nylon 612, and nylon 6/66 copolymer. By satisfying this condition, it is possible to obtain a polyamide monofilament having further excellent heat resistance and excellent wire diameter accuracy and excellent bending durability.

  The industrial fabric of the present invention is characterized in that the polyamide monofilament is used in at least a part of warp and / or weft, and the excellent heat resistance, wire diameter accuracy and bending durability of the polyamide monofilament of the present invention. In the case of a thin polyamide monofilament, it is possible to achieve a sufficient bending rigidity compared to the conventional polyamide monofilament, so that the papermaking dryer canvas, papermaking wire, papermaking It is possible to reduce the weight of industrial fabrics such as press felts and filters, and to obtain industrial fabrics having excellent heat resistance and durability.

  According to the present invention, as will be described below, it has not only extremely superior heat resistance but also excellent wire diameter accuracy and bending durability as compared with conventional polyamide monofilaments composed of various polyamide resins. Thus, a polyamide monofilament having both of the above can be obtained. Therefore, the polyamide monofilament of the present invention can be suitably used as a constituent material for industrial fabrics, especially paper fabrics.

  Hereinafter, the present invention will be described in more detail.

  The polyamide monofilament of the present invention comprises a polyamide A obtained by a polycondensation reaction of a diamine component mainly composed of metaxylylenediamine and a dicarboxylic acid component mainly composed of adipic acid, and other polyamide B. Polyamide A: 90 to 55 It is composed of a polyamide composition in which 0.01% to 5 parts by weight of a phenolic antioxidant is mixed with 100% by weight of the total amount of the other polyamide B mixed at a ratio of 10% to 45% by weight. It is characterized by.

  Further, for the polyamide A and the polyamide B constituting the polyamide monofilament of the present invention, it is essential that the difference in the relative viscosity of sulfuric acid measured is 1.2 or less, and at the same time, in a dry heat atmosphere at 180 ° C. The strength retention of polyamide monofilament when treated for 4 hours is 70% or more of the strength of untreated polyamide monofilament, the variation rate of diameter with respect to the average diameter of monofilament measured in the fiber axis direction is 10% or less, and bending The number of fatigue fractures is 5,000 times or more, and the number of bending wear fractures is 10,000 or more.

  Here, the polyamide A constituting the polyamide composition of the present invention is an aromatic polyamide resin obtained by a polycondensation reaction of a diamine component mainly composed of metaxylylenediamine and a dicarboxylic acid component mainly composed of adipic acid. In general, it is a polyamide resin called polyamide MXD6 resin (hereinafter, aromatic polyamide obtained by polycondensation reaction of a diamine component mainly composed of metaxylylenediamine and a dicarboxylic acid component mainly composed of adipic acid. The resin is referred to as MXD6).

  MXD6 constituting polyamide A of the present invention is preferably composed of 60% by mole or more of the diamine component metaxylylenediamine, and the dicarboxylic acid component is mainly composed of adipic acid, but other dicarboxylic acids. MXD6 obtained by polycondensation reaction using sebacic acid, dodecanoic acid, suberic acid, undecanoic acid or the like as the acid component can be preferably used.

  The polyamide B used in the present invention includes, for example, ring-opening polymerization of various lactams, various polyamides obtained by polycondensation of various diamines and various dicarboxylic acids and polycondensation of various aminocarboxylic acids, and polycondensates thereof. Copolyamides that combine condensation and ring-opening polymerization, such as nylon 6, nylon 66, nylon 610, nylon 46, nylon 612, nylon 11, nylon 12, nylon 6/12 copolymer (ε-caprolactam And a copolymer of nylon 6 / nylon 66 (a copolymer of ε-caprolactam and a hexamethylenediamine / adipic acid nylon salt), and the like. In addition, a mixture of two or more of these polyamides It can also be used as lyamide B.

  Among the above polyamide resins, any one or a mixture of two or more of nylon 6, nylon 66, nylon 610, nylon 612, and nylon 6/66 copolymer can be used to obtain the breaking strength and bending durability of the resulting polyamide monofilament. Among these, nylon 6, nylon 66, and nylon 6/66 copolymer are particularly preferable in view of realizing high strength, high hook strength, and excellent bending durability.

  Here, it is important that the polyamide monofilament of the present invention is a mixture of the polyamide A and the polyamide B in a range of polyamide A: polyamide B = 90 to 55 wt%: 10 to 45 wt%. Furthermore, polyamide A: polyamide B = 80 to 70% by weight: 20 to 30% by weight, more preferably polyamide A: polyamide B = 70 to 60% by weight: 30 to 40% by weight Since the improvement in durability of the monofilament becomes even more remarkable, it is preferable.

  The durability referred to in the present invention refers to the number of times of bending fatigue rupture required to cut the polyamide monofilament measured by an MIT bending fatigue tester according to JIS P-8115, or the JIS 2008 L1095 9.10.2 B method. The properties of the polyamide monofilament of the present invention were evaluated by a flexural wear property tester according to the same flexural wear property tester. The polyamide monofilament of the present invention has a flex fatigue fracture number of 5000 times or more and a flexion wear fracture number of 10,000 or more. By satisfying the properties at the same time and satisfying these bending durability at the same time, when used as an industrial fabric, it leads to excellent fabric durability.

  The polyamide monofilament of the present invention is characterized by containing 0.01% to 5 parts by weight of a phenolic antioxidant with respect to 100 parts by weight of the total of polyamide A and polyamide B described above.

Here, examples of the phenolic antioxidant that can be used in the present invention include hindered type, semi-hindered type, and less hindered type compounds. It is preferable to use a hindered phenol antioxidant having two —C (CH ₃ ) ₃ groups at the ortho position.

  Specific examples of the hindered phenol-based antioxidant include N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), octadecyl-3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino ) -1,3,5-triazine, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,5-di-tert-butyl 4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, bis (3 And ethyl 5-di-t-butyl-4-hydroxybenzylphosphonate) calcium, 2,6-di-t-butyl-4-ethylphenol and 2,6-di-t-butyl-P-cresol. In particular, Irganox 1098 (registered trademark, manufactured by Ciba Specialty Chemicals Co., Ltd.), which is N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), Since it can be easily obtained, it can be particularly preferably used. In the present invention, these phenolic antioxidants are used for polyamide A and polyamide B. By containing 0.01 to 5 parts by weight with respect to a total of 100 parts by weight, a dramatic heat resistance improvement effect is exhibited, and the polyamide after being treated for 4 hours in a dry heat atmosphere at 180 ° C., which is a feature of the present invention The strength retention of the monofilament leads to the development of excellent heat resistance of 70% or more with respect to the strength of the untreated polyamide monofilament.

  Here, when the content of the phenolic antioxidant is 0.05 to 3 parts by weight, and further 0.1 to 2 parts by weight, suppression of monofilament strength reduction and further improvement of the wire diameter accuracy, etc. However, when the content of the phenolic antioxidant is less than 0.01%, which is outside the range of the present invention, the desired heat resistance expression effect is small and the polyamide having insufficient heat resistance is obtained. Only monofilaments can be obtained. Also, if the content is too high, not only will the accuracy of the polyamide monofilament's wire diameter decrease, but when melt spinning, the extrusion characteristics of the raw material become unstable, making it impossible to discharge the molten polymer, or the addition rate This leads to inconveniences such as the molten polymer being easily discolored due to the influence of too much phenolic antioxidant.

  The polyamide A and the polyamide B constituting the polyamide composition of the present invention are prepared according to JIS K6810 by dissolving 2.5 g of a polyamide resin sample in 2.5 cc of 98% sulfuric acid and under the condition of a temperature of 25 ° C. A sulfuric acid relative viscosity (hereinafter simply referred to as a relative viscosity) measured by using 2 to 5 can be preferably used, but the relative viscosity difference between polyamide A and polyamide B used in the present invention is 1.2. It is important that:

  That is, the polyamide monofilament of the present invention is characterized in that the diameter variation rate relative to the average diameter of the monofilament measured in the fiber axis direction is 10% or less. Here, the relative viscosity difference between polyamide A and polyamide B is 1 .2 or more, when the polyamide resin having a large relative viscosity difference is fed into a spinning machine such as an extruder for performing melt spinning, melted and kneaded, and then extruded from a nozzle nozzle provided at the tip of the spinning machine, In this case, the melted and kneaded state is not uniformed and the discharge state of the molten polymer extruded from the nozzle nozzle becomes extremely unstable, making it difficult to produce a polyamide monofilament having excellent wire diameter accuracy, and the extruded state of the molten polymer. As a result of extremely worsening of the melt, the molten polymer cannot be taken out or stretched due to the discharge state in a thin state. Resulting in poor operability such as, or a large number of abnormal diameter fluctuations (hereinafter referred to as hump yarns) with a very short length in the fiber axis direction relative to the desired monofilament average diameter. This is because it leads to a very unfavorable result.

  In the polyamide monofilament of the present invention, various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, and carbon black, and various metal particles may be used according to various purposes as long as the properties are not impaired. In addition to these, conventionally known sequestering agents, ion exchange agents, anti-coloring agents, light-proofing agents, antistatic agents, various coloring agents, waxes, silicone oils, and the like may be added.

  The polyamide monofilament of the present invention having the above-mentioned configuration has excellent heat resistance, and has excellent wire diameter accuracy required for polyamide monofilaments constituting woven fabrics used in papermaking processes, including industrial fabrics. Since it can be suitably used for various industrial fiber materials and fabrics and also has excellent bending durability, industrial fabrics using this for at least a part of warps and / or wefts are particularly suitable for papermaking dryers. It is very preferable as a canvas, papermaking wire, papermaking press felt or filter.

  In addition, the polyamide monofilament of the present invention has a cross-sectional shape perpendicular to the fiber axis direction in order to satisfy its use and characteristics, and any shape such as a circle, an ellipse, a flat shape, a regular polygon, and an irregular shape. And may be a composite fiber as necessary.

  In addition, the flat here means an ellipse or a rectangle, but includes an exact ellipse defined mathematically, an ellipse, a rectangle or a similar shape in addition to a rectangle, and a regular polygon is a mathematical In addition to regular polygons that are defined in general, shapes that are substantially similar to this are included.

  Further, the diameter of the polyamide monofilament of the present invention can be appropriately selected according to the intended use, but usually a range of about 0.05 to 5 mm is suitably used, and the tensile breaking strength of these polyamide monofilaments If it is 2.5 cN / dtex or more, expression of a favorable effect as a polyamide monofilament for industrial textile use can be expected.

  Next, as a method for producing the polyamide monofilament of the present invention, it can be produced by a conventionally known method.

  For example, a phenolic antioxidant is added in the form of a powder or slurry in the polyamide monofilament melt spinning process to a polyamide mixture obtained by premixing the polyamide A and polyamide B of the present invention at a desired mixing ratio. And a method of metering and mixing polyamide A, polyamide B and a phenolic antioxidant using an automatic metering mixer before supplying the raw material to a spinning machine for melt spinning.

  In addition, a method using polyamide A and / or polyamide B in which a necessary amount of a phenolic antioxidant is blended in advance, and a polyamide in which a phenolic antioxidant is premixed with polyamide A or polyamide B at a desired blending ratio Any addition method such as A masterbatch (hereinafter, masterbatch is referred to as MB) and / or a method of adding as polyamide B-MB, the blending ratio of the phenolic antioxidant is within the scope of the present invention. If the adjustment is made, the necessary and sufficient heat resistance improvement effect can be exhibited.

  Here, from the viewpoint of handling of raw materials and production efficiency, it is more preferable to add a phenolic antioxidant as polyamide MB in which polyamide A or polyamide B is blended at a high concentration.

  Next, after using the polyamide composition in which the above polyamide A, polyamide B and phenolic antioxidant are appropriately mixed at a desired mixing ratio and melt-kneading with a spinning machine such as an extruder, a molten polyamide polymer is provided at the tip of the spinning machine. The polyamide monofilament of the present invention can be efficiently produced by extruding from the prepared spinneret nozzle and performing cooling, stretching and heat setting by a known method.

  The polyamide monofilament of the present invention thus formed has excellent heat resistance that is not found in conventional polyamide monofilaments, and also has excellent wire diameter accuracy, and by using MXD6 as a constituent material, a narrow-diameter polyamide monofilament Even in the case of having a sufficient bending rigidity not found in conventional polyamide monofilaments, it can be suitably used as a constituent material for industrial fabrics, in particular, in addition to high heat resistance and excellent wire diameter accuracy, Since it has excellent bending durability, industrial fabrics that use it for at least part of warp and / or wefts exhibit extremely excellent properties as a papermaking dryer canvas, papermaking wire, papermaking press felt, or filter. It can be said that it is a thing.

  Hereinafter, examples of the polyamide monofilament of the present invention will be described in more detail. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

  Further, in the polyamide monofilament of the present invention described above and below, the sulfuric acid relative viscosity of the polyamide, the bending fatigue property test, the bending wear property test, the diameter variation rate, the strength retention rate of the polyamide monofilament after dry heat treatment and the yarn forming property, etc. The evaluation was measured and evaluated by the following method.

(1) Sulfuric acid relative viscosity (ηr)
According to JIS K6810, 2.5 g of a polyamide resin sample was dissolved in 2.5 cc of 98% sulfuric acid and measured using an Ostwald viscometer at a temperature of 25 ° C.

(2) Bending fatigue property test According to JIS P-8115, manufactured by Toyo Seiki Co., Ltd .: MIT load resistance tester, load 2.2 cN / dtex, number of bendings 175 times / minute, bending angle 270 degrees (left and right) Measure the number of reciprocating folds until 10 monofilaments are cut per sample under the conditions of about 135 degrees each) and the curvature radius of the left and right bending surfaces of the folding piece sandwiching the monofilaments is 0.38 ± 0.02 mm. The average value was obtained.

(3) Flex abrasion characteristics test It measured with the flex abrasion characteristics tester according to JIS2008 L1095 9.10.2 B method. That is, a monofilament brought into contact with a fixed friction piece (hard steel wire (SWP-A)) having a diameter of 1.0 mm was provided so that the monofilament was bent at an angle of 55 ° to the left and right of the friction piece. Hang it under two free rollers (distance 100 mm between the two rollers) and set it with a load of 0.196 cN / dtex on one end of the monofilament over another free roller. The polyester monofilament was brought into reciprocating contact with the friction element at a speed of 120 reciprocations / minute and a reciprocating stroke of 25 mm, and the number of times until the polyamide monofilament broke was measured.

(4) Average diameter (mm)
A monofilament sample is taken into a 50-meter bowl shape and cut (50 pieces) into a sample length of 100 cm. 20 samples were taken arbitrarily from here, and the diameter of each polyamide monofilament was measured using Anritsu Corporation laser outer diameter measuring machine KL15X series (detection part: KL151A, display part: KL350A), and the average value was calculated as the average diameter. It was.

(5) Monofilament diameter fluctuation rate (%)
Using Anritsu Corporation laser outer diameter measuring machine KL15X series (detection part: KL151A, display part: KL350A), the monofilament was run at a speed of 50 m / min, and the outer diameter was measured for 10 minutes. Yokogawa Electric Corporation A wire diameter chart (diameter spot) was recorded with a recorder LR4220. The maximum value and the minimum value of the diameter of the measured monofilament sample are obtained from this wire diameter recording chart, the difference A (maximum value−minimum value: unit mm) is calculated, and the variation with respect to the average diameter of the monofilament obtained by the above average diameter measurement Was the diameter variation rate. In addition, the formula of a diameter fluctuation rate is a diameter fluctuation rate (%) = (A ÷ average diameter) × 100, and a smaller diameter fluctuation rate indicates a monofilament having a uniform wire diameter.

(6) Strength retention after dry heat treatment (%)
A 50 cm cut monofilament sample is bundled and dry heat-treated for 4 hours under a temperature condition of 180 ° C. using a gear oven GPHH-101 manufactured by Tabai Espec Co., Ltd.

  Ten monofilament samples after dry heat treatment were used according to JIS2008 L1013 8.5, “Tensilon” UTM-4-100 type tensile tester manufactured by Orientec Co., Ltd., test length: 250 mm, tensile speed: 300 mm The tensile strength was measured under the conditions of / min and the average value was calculated. Under the same conditions, the tensile strength of 10 samples before dry heat treatment was measured to calculate an average value, and the monofilament strength retention before and after the dry heat treatment was calculated from these average values. The formula is: strength retention after dry heat treatment (%) = (strength of monofilament after dry heat treatment ÷ strength of monofilament before dry heat treatment) × 100, and the higher the strength retention, the more thermally stable and excellent It is a monofilament having dry heat resistance.

(7) Spinnability (operability)
24 hours of continuous spinning was carried out and judged according to the following criteria.
○ (Good): There is no yarn-making state due to poor biting of the raw material or melt-extrusion failure, no yarn breakage during yarn production, and 10 times of occurrence of bumps exceeding + 10% of the monofilament average diameter It was less than / ton.
In addition, the number of times of the hoop yarn was calculated by the following formula: Spinning extrusion total polymer weight (kg) / 1000 kg × number of hoop yarns.
X (Bad): Evaluation was made based on two criteria: a state in which the yarn could not be produced due to a poor raw material biting or a poor melt extrusion, a yarn breakage occurred during the yarn production, and a knot yarn was generated 10 times / ton or more.

[Example 1]
As polyamide A, MXD6 (Nylon MXD6 S6121 manufactured by Mitsubishi Gas Chemical Co., Inc.) having a relative viscosity of 3.88 is 60% by weight, and as polyamide B, nylon 6 (M1041 manufactured by Toray Industries, Inc.) having a relative viscosity of 4.46 is 40% by weight. %, N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) (Ciba Specialty Chemicals Co., Ltd.) as a phenolic antioxidant ) A polyamide composition prepared by mixing 0.5 parts by weight of Irganox 1098) was prepared.

  This polyamide composition was supplied to an extruder-type spinning machine, melt kneaded at a temperature of 290 ° C., extruded from a spinning nozzle, and then immediately obtained by cooling and solidifying in 50 ° C. warm water.

  Subsequently, the undrawn yarn was drawn at a total draw ratio of 4.5 times and heat-set according to a conventional method to obtain a polyamide monofilament having an average diameter of 0.25 mm.

  Table 1 shows the results of evaluating the strength retention after dry heat treatment, the diameter fluctuation rate, the number of flexural fatigue fractures, the number of flexural wear fractures, the yarn forming property, and the like of the obtained polyamide monofilament.

[Comparative Example 1]
A polyamide monofilament having an average diameter of 0.25 mm obtained by using a polyamide composition in which 0.5 parts by weight of a phenolic antioxidant is added to 100 parts by weight of the same polyamide A as used in Example 1 is dried. Table 1 shows the results of evaluation of the strength retention after heat treatment, the diameter fluctuation rate, the number of bending fatigue fractures, the number of bending wear fractures, the yarn forming property, and the like.

[Examples 2-3 and Comparative Examples 2-4]
Tables 1 to 3 show only the mixing ratios of polyamide A and polyamide B among the mixing ratios of the final polyamide composition using the same polyamide A, polyamide B and phenolic antioxidant as in Example 1. Thus, a polyamide monofilament having an average diameter of 0.25 mm was obtained.

  Tables 1 to 3 show the evaluation results of the obtained polyamide monofilament after dry heat treatment for strength retention, diameter fluctuation rate, number of bending fatigue ruptures, number of bending wear ruptures and yarn-forming properties.

[Examples 4 and 5]
As polyamide A, MXD6 (Nylon MXD6 S6007 manufactured by Mitsubishi Gas Chemical Co., Inc.) having a relative viscosity of 2.97 and nylon 6 (M1021T manufactured by Toray Industries, Inc.) having a relative viscosity of 3.41 as polyamide B are mixed as shown in Table 1. The total amount was 100 parts by weight, and N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) (Ciba Specialty Chemicals ( A polyamide composition in which 0.5 part by weight of Irganox 1098) manufactured by Co., Ltd. was mixed was prepared and spun under the same conditions as in Example 1 to obtain a 0.25 mm polyamide monofilament.

  Table 1 shows the results of evaluation of the strength retention rate, the diameter fluctuation rate, the bending fatigue rupture number, the bending wear rupture number, the yarn forming property, and the like after dry heat treatment of each obtained polyamide monofilament.

[Example 6]
As polyamide A, MXD6 having a relative viscosity of 2.32 (Nylon MXD6 S6001 manufactured by Mitsubishi Gas Chemical Co., Ltd.) and nylon 6 having a relative viscosity of 3.41 as polyamide B (M1021T manufactured by Toray Industries, Inc.) shown in Table 1 are mixed. The total amount was 100 parts by weight, and N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) (Ciba Specialty Chemicals ( A polyamide composition in which 0.5% by weight of Irganox 1098) manufactured by Co., Ltd. was mixed was prepared and spun under the same conditions as in Example 1 to obtain a 0.25 mm polyamide monofilament.

  Table 1 shows the evaluation results of the obtained polyamide monofilaments for strength retention after dry heat treatment, rate of fluctuation in diameter, number of bending fatigue breaks, number of bending wear breaks, yarn forming properties, and the like.

[Examples 7 to 9 and Comparative Examples 6 to 7]
Tables 1 to 3 show only the mixing ratio of the phenolic antioxidant among the mixing ratio as the final polyamide composition using the same polyamide A, polyamide B and phenolic antioxidant as in Example 1. Using the polyamide composition changed to 1, spinning was performed under the same conditions as in Example 1 to obtain a polyamide monofilament of 0.25 mm.

  Tables 1 to 3 show the results of evaluating the strength retention rate after dry heat treatment, the diameter fluctuation rate, the number of flexural fatigue fractures, the number of flexural wear fractures, the yarn forming property, and the like of each obtained polyamide monofilament.

[Examples 10 to 12 and Comparative Example 5]
As the mixing ratio of the same polyamide composition as in Example 1, the polyamide monofilament with an average diameter of 0.25 mm obtained by changing the resin type and relative viscosity of polyamide B as shown in Tables 2 and 3 was strong after dry heat treatment. Tables 2 and 3 show the results of evaluating the retention rate, the diameter variation rate, the bending fatigue rupture frequency, the bending wear rupture frequency, the yarn-making property, and the like. Polyamide B used in Examples 10 to 12 is 6/66 copolymer nylon made by Toray Industries, Inc. M6151 (relative viscosity 4.87), and nylon 66 made by Toray Industries, Inc. M3001 (relative viscosity 2.92). ), Nylon 610 is M2001 (relative viscosity 2.71) manufactured by Toray Industries, Inc., and nylon 6 used in Comparative Example 5 is M1010 (relative viscosity 2.63) manufactured by Toray Industries, Inc.

  As is clear from the results in Tables 1 and 2, the polyamide monofilaments (Examples 1 to 12) according to the present invention both have high heat resistance and excellent wire diameter accuracy, and are also required to have high bending as an industrial fabric. It can be seen that it also has durability.

  On the other hand, polyamide monofilaments that do not satisfy the requirements of the present invention have insufficient heat resistance, low bending durability such as bending fatigue and bending wear, and also to realize the surface smoothness of industrial fabrics. It is clear that none of the polyamide monofilaments constituting the industrial fabric is unfavorable and that the yarn-making property is insufficient, such as the critical monofilament diameter accuracy is low.

  That is, the polyamide monofilament of Comparative Example 1 containing no polyamide B has excellent heat resistance and wire diameter accuracy, but has extremely low bending characteristics such as bending fatigue and bending wear. Furthermore, in Comparative Example 2, which contains polyamide B but has a very low mixing rate, the effect of improving durability by adding polyamide B is insufficient, and only a polyamide monofilament that cannot satisfy durability can be obtained. It was.

  Moreover, in Comparative Example 3 and Comparative Example 4 in which the mixing ratio of polyamide B deviates from the provisions of the present invention, the discharge stability of the polymer extruded from the nozzle nozzle deteriorates. As a result, not only a polyamide monofilament with a low yarn diameter can be obtained, but also the knot yarn is generated 10 times / ton or more. In particular, in Comparative Example 4 in which the mixing ratio of polyamide B is higher than that of polyamide A MXD6, the effect of the phenolic antioxidant is insufficient, and the polyamide has low heat resistance performance in addition to the yarn forming property and the wire diameter accuracy. The result was extremely unfavorable, such as a monofilament.

  In Comparative Example 5 in which the relative viscosity difference between polyamide A and polyamide B deviates from the provisions of the present invention, the difference in viscosity between two or more polyamide resins melt-kneaded in an extruder type spinning machine or the like is too large. As a result, the polymer to be melt extruded cannot be discharged stably, resulting in a monofilament having a low wire diameter accuracy, and the yarn forming property is also deteriorated, for example, the knot yarn is generated 29 times / ton.

  Furthermore, in Comparative Example 6 and Comparative Example 7 in which the phenolic antioxidant is not included in the definition of the present invention, in the case of Comparative Example 6 in which the mixing ratio is too high, due to the influence of the phenolic antioxidant that is mixed in a large amount. However, the characteristics of the raw material biting into the screw of the extruder-type spinning machine deteriorated, and not only the problem of being unable to discharge became sporadic, but continuous yarn production for 5 hours or more became impossible. On the other hand, in the case of Comparative Example 7 in which the mixing ratio of the phenolic antioxidant was too low, only a polyamide monofilament having insufficient heat resistance was obtained.

  As described above, the polyamide monofilament of the present invention has excellent heat resistance, and even when subjected to a thermal history under high temperature dry heat conditions, there is very little reduction in strength due to thermal degradation, and excellent wire diameter accuracy and Since it has a bending durability performance and also has an excellent bending rigidity specific to MXD6, it can be suitably used as a constituent material for industrial fabrics such as a papermaking dryer canvas, papermaking wire, papermaking press felt or filter.

Claims (4)

A polyamide diamine obtained by a polycondensation reaction of a diamine component mainly composed of metaxylylenediamine and a dicarboxylic acid component mainly composed of adipic acid and another polyamide B, and the relative sulfuric acid between the polyamide A and the polyamide B The viscosity difference is within 1.2, and 0.01 to 5 parts by weight of a phenolic antioxidant is contained with respect to 100 parts by weight in total of 90 to 55% by weight of the polyamide A and 10 to 45% by weight of the polyamide B. A polyamide monofilament comprising a polyamide composition, wherein the polyamide monofilament has a strength retention of 70% or more of the untreated polyamide monofilament when treated for 4 hours in a dry heat atmosphere at 180 ° C., in the fiber axis direction. The diameter variation rate with respect to the average diameter of the monofilament measured in 10% or less, Song fatigue fracture number more than 5000 times, polyamide monofilament, characterized in that the number flexing abrasion broken simultaneously satisfies 10000 or more times characteristics. The polyamide monofilament according to claim 1, wherein the polyamide B is at least one selected from nylon 6, nylon 66, nylon 610, nylon 612, and nylon 6/66 copolymer. An industrial fabric, wherein the polyamide monofilament according to any one of claims 1 and 2 is used for at least part of warp and / or weft. The industrial fabric according to claim 3, wherein the industrial fabric is a papermaking dryer canvas, a papermaking wire, a papermaking press felt, or a filter.