Polyamide multifilament and knitted fabric

Abstract

Provided is a polyamide multifilament which has a fine single-yarn fineness, a product of strength and elongation, and excellent wear resistance. Also provided are a woven fabric using the polyamide multifilament according to the present invention and having excellent tear strength, wear resistance, and air permeability, and a woven fabric having excellent breaking strength, wear resistance, and flexibility. The present invention relates to a polyamide multifilament comprising a core-sheath composite cross-section polyamide fiber, the crystallinity of the sheath part being 35% or less, the single-yarn fineness being 3.0 dtex or less, and the product of strength and elongation being 5.5 or more.

Description

Technical Field

[0001] This invention relates to a polyamide multifilament and woven fabric with excellent abrasion resistance.

[0002] This invention provides a woven fabric with excellent durability when the polyamide multifilament of the present invention is used in woven fabrics. Background Technology

[0003] Polyamide multifilament, as a synthetic fiber, is widely used in clothing applications such as underwear, sportswear, and outdoor apparel due to its excellent properties in terms of softness, durability, color development during dyeing, heat resistance, and moisture absorption.

[0004] In recent years, due to increased awareness of sustainable social development, especially for clothing used in harsh environments for sports and outdoor applications, there is a growing demand for products with long lifespans and high durability.

[0005] In terms of resistance to breakage or abrasion, polyamide is superior to polyester. Existing polyamide multifilaments also have excellent durability, but higher durability is required.

[0006] In clothing intended for sports and outdoor use, deterioration occurs, particularly due to tearing caused by snagging on obstacles such as rocks or trees, and wear caused by friction with these obstacles.

[0007] Therefore, polyamide multifilaments with excellent durability are required to have both high strength and excellent abrasion resistance.

[0008] As a yarn-making technology for high-strength polyamide multifilaments, for example, in Patent Document 1, a heating layer is applied in a circumferential shape directly above the cooling section immediately after the die is ejected, so that the multifilament is cooled slowly, thereby providing a high-strength polyamide multifilament with a tensile product of 10.0 or more.

[0009] In addition, as a yarn-making technology for high-strength polyester multifilament, for example, Patent Document 2 provides a polyester multifilament that achieves high strength and excellent abrasion resistance by configuring a high-viscosity polyester in the core and a low-viscosity polyester in the sheath.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: International Publication No. 2018 / 021011

[0013] Patent Document 2: International Publication No. 2019 / 107111 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] However, the method described in Patent Document 1 actively increases the amount of polymer crystals in order to obtain high-strength yarn. Since the polymer crystals are rigid, the yarn described in Patent Document 1 suffers from the problem of being prone to whitening due to friction and being less wear-resistant.

[0016] Furthermore, the yarn described in Patent Document 2 has low strength and abrasion resistance because it originally uses polyester, and the problem is not adequately solved by simply addressing the viscosity difference between the polyester used in the core and the polyester used in the sheath.

[0017] The present invention solves the aforementioned problem and provides a polyamide multifilament that provides excellent durability against damage or abrasion.

[0018] Technical means to solve the problem

[0019] To address the aforementioned issues, the present invention has the following structure.

[0020] (1) A polyamide multifilament comprising a core-sheath type composite profile polyamide fiber, wherein the crystallinity of the sheath is less than 35%, the fineness of the single yarn is less than 3.0 dtex, and the tensile strength product is more than 5.5.

[0021] (2) According to the polyamide multifilament described in (1), wherein the amide orientation parameter of the core of the core-sheath type composite profile polyamide fiber is 1.5 or higher.

[0022] (3) A woven fabric, a portion of which comprises polyamide multifilaments according to (1) or (2).

[0023] The effects of the invention

[0024] The polyamide multifilament of the present invention provides a woven fabric suitable for sports and outdoor clothing, which exhibits excellent durability against damage or abrasion. Attached Figure Description

[0025] [ Figure 1 ] Figure 1 This is a diagram illustrating one embodiment of a manufacturing apparatus that can be used in the manufacturing method of polyamide multifilaments according to the present invention.

[0026] [ Figure 2 ] Figure 2 This is a schematic diagram showing the cross-sectional view of the polyamide multifilament of the present invention. Detailed Implementation

[0027] Regarding the polyamide multifilament of the present invention, excellent fabric properties against breakage are achieved by increasing the tensile-elongation product, and excellent fabric properties against friction are achieved by suppressing the crystallinity of the sheath. Generally speaking, the increase in the tensile-elongation product of yarn and abrasion resistance are, from the viewpoint of orientation or crystallization, a trade-off. The inventors believe that by setting the cross-section of the polyamide fiber to a core-sheath composite cross-section, both the tensile-elongation product in the core and the abrasion resistance in the sheath can be achieved.

[0028] Therefore, regarding the polyamide multifilament of the present invention, the tensile strength product, the crystallinity of the sheath, and the fineness of the single yarn are set within the aforementioned range.

[0029] That is, the polyamide multifilament of the present invention is a polyamide multifilament comprising core-sheath type composite profile polyamide fiber, wherein the crystallinity of the sheath is less than 35%, the single yarn fineness is less than 3.0 dtex, and the tensile strength product is more than 5.5.

[0030] In particular, in clothing materials for sports and outdoor use, or in the base fabrics of down garments, low breathability is required due to the need for a soft, pleasant feel and to prevent down leakage. Therefore, the yarn fineness is set in the aforementioned range. On the other hand, in areas with fine yarn fineness, the fabric is extremely susceptible to damage or abrasion when made from these fine yarns.

[0031] In this invention, as a method to improve the durability of a single yarn to a fabric against damage or abrasion, the tensile strength product and the crystallinity of the sheath are set within the aforementioned range.

[0032] The polyamide resin contained in the core-sheath type composite profile polyamide fiber of this invention is not particularly limited as long as it is a so-called polyamide resin in which hydrocarbon groups are linked to the main chain via amide bonds. As a polyamide resin, there are polyamide 6 or polyamide 66. In recent years, as an environmentally friendly raw material, polyamide 410, polyamide 510, polyamide 610, polyamide 612, polyamide 1010, polyamide 11, polyamide 12, etc., which contain biomass raw materials, are all acceptable. It can also be a polyamide obtained through material recycling or a polyamide obtained through chemical recycling.

[0033] In addition, as a method to inhibit crystallization, copolyamide can be used as a sheath component to form the sheath. However, it is generally known that the melting point decreases and embrittlement is easily aggravated during high-temperature treatments such as dyeing. It is preferable to use polyamide with a monomer content of 80 mol% or more.

[0034] The core-sheath type composite profile polyamide fiber in this invention may also contain inorganic particles.

[0035] The content of various inorganic particles such as matting agents is not particularly limited relative to the polyamide resin, but the content is preferably 3.0% by mass or less relative to the polymer.

[0036] Since the core mainly bears the strength-tensile product, the content of inorganic particles, represented by titanium dioxide, is preferably less than 3.0% by mass relative to the polymer.

[0037] On the other hand, since the sheath mainly bears the responsibility of wear resistance, the content of inorganic particles, represented by titanium dioxide, is preferably 0.1% to 3.0% by mass relative to the polymer.

[0038] The core-sheath composite profile in this invention refers to a core-sheath composite profile in which the core is completely covered by the sheath in the fiber cross-section, and the core is arranged in a manner that does not expose the fiber surface. By forming such a profile, high durability against damage or abrasion can be achieved.

[0039] Here, the term "core-sheath type" simply means that the core is completely covered by the sheath, and is not limited to being arranged in concentric circles. The cross-sectional shape of the fiber can be round, flat, triangular, square, pentagonal, etc., but a round shape is preferred.

[0040] The single yarn fineness of the core-sheath type composite profile polyamide fiber constituting the polyamide multifilament of the present invention is 3.0 dtex or less, which is important for achieving softness in clothing such as sports and outdoor apparel, down jacket base fabric, and knitted underwear. A single yarn fineness of 2.2 dtex or less is preferred. When the single yarn fineness is coarser than 3.0 dtex, the fabric has low softness, resulting in a poor hand feel required for clothing applications. On the other hand, a finer single yarn fineness is preferred for achieving softness, but this reduces the single yarn strength, leading to decreased tear resistance and abrasion resistance of the fabric. Therefore, the lower limit of the single yarn fineness in the present invention is preferably 0.5 dtex.

[0041] The total fineness of the polyamide multifilament of the present invention is preferably 4 dtex to 100 dtex for clothing applications. For sports and outdoor clothing applications, 4 dtex to 100 dtex is suitable, and for knitted underwear applications, 22 dtex to 66 dtex is suitable.

[0042] The strength of the polyamide multifilament of the present invention is preferably 3.5 cN / dtex or higher, which can be set to 4.5 cN / dtex or higher by stretching, and can be set to 4.2 cN / dtex or higher by processing.

[0043] Regarding the elongation of the polyamide multifilament of the present invention, if it is a full-drawn yarn (FDY), it is preferably set to 30% to 50%; if it is a partially-oriented yarn (POY), it is preferably set to 60% to 90%; and if it is a drawn-textured yarn (DTY) obtained by processing POY, it is preferably set to 30% to 50%.

[0044] The polyamide multifilament of the present invention has a tensile strength product of 5.5 or higher. A tensile strength product of 6.0 or higher is preferred. When the tensile strength product is lower than 5.5, the fabric's durability against tearing is poor, which is required for clothing intended for sports and outdoor use. On the other hand, a higher tensile strength product is preferred to improve the fabric's durability against tearing, but the upper limit of the tensile strength product in the present invention is 10.0.

[0045] In this invention, the crystallinity of the sheath portion of the core-sheath type composite profile polyamide fiber is 35% or less. Preferably, the crystallinity is 33% or less. The crystallinity of the sheath portion is determined by Raman spectroscopy, using vertical spectroscopy, according to… Nearby The bandwidth of the elongation vibration mode is the calculated value. Higher crystallinity indicates higher polymer stiffness.

[0046] The sheath portion of the core-sheath type composite profile polyamide fiber bears the burden of friction durability for the core-sheath type composite profile polyamide fiber, and thus the polyamide multifilament. Therefore, low stiffness and lower crystallinity are preferred. When the crystallinity is higher than 35%, the orientation of the sheath portion advances, the polymer becomes stiff, and therefore it is prone to whitening when subjected to friction, resulting in poor friction durability. Especially for sports and outdoor clothing where long-term product life is sought, the crystallinity of the sheath portion is set to 35% or less. On the other hand, to improve the friction durability of the fabric, lower crystallinity of the sheath portion is preferred, but the lower limit value of the crystallinity of the sheath portion in this invention is 20%.

[0047] In this invention, the amide orientation parameter of the core of the core-sheath type composite profile polyamide fiber is preferably 1.5 or higher. The amide orientation parameter of the core mentioned here is determined by Raman spectroscopy, using parallel and perpendicular spectroscopy. Nearby The value is calculated from the ratio of the peak intensities of the elongation vibration modes.

[0048] In core-sheath type composite profile polyamide fibers, the core bears the strength-elongation product of the multifilament, therefore, a higher amide orientation parameter is preferred. The preferred amide orientation parameter is 1.7 or higher, with an upper limit of 3.0.

[0049] Reference Figure 1An example of manufacturing the polyamide multifilament of the present invention will be described.

[0050] Polyamide, comprising the core component and the sheath component, is melted separately, metered and conveyed using a gear pump, and ejected from the composite spinning die 1. The yarn is cooled to room temperature and solidified by a steam jetting device that sprays steam directly below the spinning die and by a cooling airflow blowing from a cooling device 2 located downstream of the steam jetting device. Then, oil is supplied by an oil supply device 3 to bundle the yarn, which is then interwoven through a fluid interlacing nozzle device 4 and passed through a traction roller 5 and an extension roller 6. At this point, the yarn is extended according to the ratio of the circumferential speeds of the traction roller and the extension roller. Furthermore, the yarn is heat-set by heating the extension roller and then wound by a winding machine (winding device 7).

[0051] The polyamide multifilament of the present invention can not only be manufactured using the aforementioned manufacturing method, but can also be made into highly oriented unstretched yarn that is not stretched between the traction roller and the stretching roller. In addition, it can also be manufactured through a two-stage process of stretching after obtaining the unstretched yarn.

[0052] The polyamide resin used in the polyamide multifilament of the present invention is preferably formulated in a way that the core component promotes orientation or crystallization and the sheath component inhibits orientation or crystallization during the yarn-making process.

[0053] The polyamide resin used in the core and sheath of the polyamide multifilament of the present invention is preferably a polyamide for the core component and a polyamide for the sheath component with a melt viscosity of more than 500 poise at a typical polyamide spinning temperature of 270°C.

[0054] By setting the melt viscosity to 500 poise or higher, the stress on the yarn between the extrusion and traction rollers of each polyamide extruded from the die can be biased towards the core component, promoting orientation or crystallization and inhibiting the orientation or crystallization of the sheath component, thereby controlling the tensile strength product and the crystallinity of the sheath.

[0055] The polyamide resin used in the core and sheath of the polyamide multifilament of the present invention is preferably a polyamide for the core component relative to a polyamide for the sheath component, and the relative viscosity of the sulfuric acid is... It also has high viscosity. The difference is effective when it is above 0.5. By setting it to above 0.5, even during stretching, the stress can be biased towards the core component, promoting orientation or crystallization, and inhibiting the orientation or crystallization of the sheath component, thereby controlling the crystallinity of the polyamide in the tensile-stretch product and the sheath component.

[0056] Furthermore, in the combination of polyamides for the core component and the sheath component, it is preferable that the polyamide for the core component has the same or higher melting point than the polyamide for the sheath component.

[0057] The melting point of polyamide is closely related to the curing point (curing point) of each polymer during melt spinning. If the curing point is early, the polyamide is more susceptible to stress during the spinning process, thus facilitating orientation or crystallization. Therefore, for the core component that is intended to promote orientation or crystallization, the curing point needs to be at least as early as possible compared to the sheath component that is intended to inhibit orientation or crystallization; preferably, the melting point should be set to be at least as early as possible.

[0058] In order to effectively demonstrate the effects of the present invention, the addition of various inorganic particles, such as matting agents represented by titanium dioxide, is not particularly limited relative to the polyamide used in the core and sheath, but the amount is preferably 3.0% by mass or less relative to each polymer.

[0059] When the amount added to the core component exceeds 3.0% by mass, it becomes a foreign substance relative to the polymer, thus hindering orientation and preventing the attainment of a sufficient strength-to-elasticity product.

[0060] Furthermore, when the amount added to the sheath component exceeds 3.0% by mass, the inorganic particles generally have high thermal conductivity, thus becoming cooling points and promoting the cooling of the polymer. The curing point becomes faster, resulting in stress and increased crystallinity, which makes it impossible to obtain sufficient wear resistance.

[0061] Since the polyamide core component mainly bears the strength-tensile product, the amount of inorganic particles, represented by the added titanium dioxide, is preferably less than 3.0% by mass.

[0062] On the other hand, since the polyamide component of the sheath mainly bears the responsibility of wear resistance, it is preferable to add about 0.1% to 3.0% by mass of inorganic particles, represented by titanium dioxide.

[0063] The core-sheath type composite profile polyamide fiber in this invention preferably has a core-sheath ratio (core / sheath ratio) of 50 / 50 to 90 / 10 by weight. More preferably, the core-sheath ratio is 70 / 30 to 80 / 20. A sheath ratio of only 10% is sufficient to adequately cover the core. A higher core ratio is preferred to increase the strength-elongation product; a ratio of 50% or higher is sufficient to obtain a adequate strength-elongation product.

[0064] The circumferential speed of the traction roller is preferably set to 2500 m / min or less. By setting the circumferential speed of the traction roller to 2500 m / min or less, the absolute value of the stress between the ejection point and the traction roller can be suppressed, thereby suppressing the crystallinity of the sheath.

[0065] The temperature of the traction roller is preferably set to 50°C or below. By setting the temperature of the traction roller to 50°C or below, during the process of extending the core by the ratio of the circumferential speeds of the traction roller and the extension roller, stress can be directed towards the polymer of the core component, thereby increasing the amide orientation parameter of the core and suppressing the crystallinity of the sheath.

[0066] This is a method that cannot be achieved by using polyester with a high glass transition temperature and heating the traction roller to near the glass transition temperature. It is the key point discovered by the inventors and others through their hard work.

[0067] Example

[0068] The present invention will be described in more detail below through embodiments.

[0069] A. Strength, elongation, strength-elongation product

[0070] Fiber specimens were tested according to Japanese Industrial Standards (JIS) L 1013-2010 - Tensile strength and elongation determination. Test conditions included a constant-speed tension testing machine, a gripping interval of 50 cm, and a tensile speed of 50 cm / min. Furthermore, the maximum strength and elongation at the point of cut were measured when the strength at cut was lower than the maximum strength.

[0071] Strength and the strength-elasticity product are calculated using the following formula.

[0072] Strength = Strength at cut (cN) / Fineness (dtex)

[0073] Elongation = Elongation at cut (%)

[0074] Strength-elongation product = Strength × ((100 + elongation) / 100).

[0075] B. Fineness

[0076] A fiber sample was placed in a measuring device with a rotation speed of 1.125 m / s and rotated 500 times to form a looped skein. This looped skein was then dried using a hot air dryer. (60 minutes), use a balance scale to measure the skein mass, and calculate the fineness (dtex) based on the value obtained by multiplying by the standard moisture regain.

[0077] C. Relative viscosity of sulfuric acid

[0078] 0.25 g of polyamide fragments or fiber samples were dissolved to make 1 g of sulfuric acid in 100 ml of 98% by mass solution. The flow time (T1) at 25°C was measured using an Oswald viscometer. Subsequently, the flow time (T2) of sulfuric acid in 98% by mass solution was measured only. The ratio of T1 to T2, i.e., T1 / T2, is set as the relative viscosity of sulfuric acid.

[0079] D. Inorganic particle content

[0080] The crucible was fired in an electric furnace at 800°C for 2 hours, cooled for 1 hour, and then precisely weighed (A1). A fiber sample (S) dried to less than 300 ppm was measured in the crucible and heated using an electric furnace and gas burner. The crucible was then heated in an electric furnace at 800°C for 2 hours, cooled for 1 hour, and then precisely weighed. This process of heating and heating using an electric furnace and gas burner, followed by heating and cooling and then precise weighing, was repeated until the same value as the previous precise weighing result was achieved. This precise weighing result is designated as (A2), and the inorganic particle content is calculated using the following formula.

[0081]

[0082] E. Melt viscosity

[0083] For fragmented samples, the moisture regain was set to below 200 ppm using a vacuum dryer, and the melt viscosity was determined by varying the strain rate in stages using a Capilograph 1B laser manufactured by Toyo Seiki. Furthermore, the measurement temperature was set to the spinning temperature, and the time from sample placement in the heating furnace to the start of the measurement was set to 5 minutes, with the measurement conducted under a nitrogen atmosphere.

[0084] F. Storage elastic modulus

[0085] The dynamic viscoelasticity of fiber samples was evaluated by sweeping them from 35°C to 100°C using an AND-manufactured DDV-GP (Rheovibron) automated dynamic viscoelasticity tester. The viscoelastic behavior at 40°C was analyzed, taking into account the yarn temperature at mechanical contact points such as guides. In this temperature range, elastic behavior predominated, thus exhibiting a stored elastic modulus.

[0086] G. Amide Orientation Parameters

[0087] Measurements were performed using Raman spectroscopy with a Jobin Yvon / Atago Bussan Corporation T-64000 microscope. The settings were: measurement mode: micro Raman; objective lens: ×100; beam diameter: 1 μm; light source: Ar. +The measurements were performed under the following conditions: laser wavelength: 514.5 nm; laser power: 100 mW; diffraction grating: single 600, 1800 gr / mm; slit size: 100 μm; detector: Jobin Yvon charge-coupled device (CCD) 1024×256. After embedding the sample in resin (bisphenol-based epoxy resin, 24-hour curing), it was sliced ​​using a pick-and-place machine at a cutting angle of less than 5° along the fiber length. The sliced ​​sample was 1.5 μm thick and cut through the center of the fiber. Orientation was determined under polarization conditions. The case where the polarization direction was aligned with the fiber length direction was defined as parallel polarization ( / / ), and the case where it was orthogonal was defined as perpendicular polarization (⊥). The Raman bands obtained were determined based on their affiliation to 1640 cm⁻¹. -1 The degree of orientation is evaluated by the ratio of the peak intensities of the nearby C=O elongation vibration modes. That is, the amide orientation parameter = (I1640)⊥ / (I1640) / / . The orientation parameter is calculated by irradiating an arbitrary point in the core with a laser. Furthermore, the orientation parameter is calculated using the average value of five single yarns randomly sampled from the core-sheath composite yarn.

[0088] H. Crystallinity

[0089] Crystallinity is the same as the amide orientation parameter, and is determined using laser Raman spectroscopy through polyamide. Nearby C The bandwidth of the stretching vibration mode of O is used for calculation. Before its calculation, five levels of raw yarn with different crystallinity are prepared from individual polyamide yarns. Crystallinity is determined based on X-ray analysis and laser Raman spectroscopy. Nearby C The bandwidth calibration curve of the stretching vibration mode of O was obtained, and then the bandwidth of the original yarn of the present invention was calculated by laser Raman spectroscopy. At this time, the crystallinity was calculated by irradiating the sheath with a laser at any point. In addition, the crystallinity was calculated using the average value of 5 single yarns randomly sampled from the core-sheath composite yarn.

[0090] I. Evaluation of textile products

[0091] (a) Tear strength

[0092] Tear strength was determined for the fabric according to JIS L1096-2020 - Tensile Strength, Single Tongue Method (Method A). The warp tear strength was measured three times, and the average value was used for evaluation in four stages based on the following criteria.

[0093] (For fabric raw yarns with a strength of less than 50 dtex)

[0094] A: 6.0 N or more,

[0095] B: 5.0 N or more but less than 6.0 N

[0096] C: 4.0 N or more but less than 5.0 N

[0097] D: Less than 4.0 N

[0098] Set A and B as having acceptable tear strength.

[0099] (For cases where the raw yarn supplied to the fabric is 50 dtex or higher)

[0100] A: 12.0 N or more,

[0101] B: 10.0 N or more but less than 12.0 N

[0102] C: 8.0 N or higher but less than 10.0 N

[0103] D: Less than 8.0 N

[0104] Set A and B as having acceptable tear strength.

[0105] (b) Wear intensity

[0106] Wear strength was measured on the fabric according to JIS L1096-2020 - Wear Strength, Steel Blade Method (F-1 Method). Five measurements were performed, and the fabric was evaluated in four stages based on the average rotational speed at which holes appeared, according to the following criteria.

[0107] A: 10,000 RPM or higher

[0108] B: 8000 RPM or higher but less than 10000 RPM

[0109] C: 6000 RPM or higher but less than 8000 RPM

[0110] D: Below 6000 RPM

[0111] Set A and B as having acceptable wear strength.

[0112] (c) Durability

[0113] Durability is evaluated using (a) tear strength and (b) abrasion strength, in accordance with the following table.

[0114] [Table 1]

[0115] Table 1

[0116]

[0117] Set A and B as having acceptable durability.

[0118] (d) Air permeability

[0119] The air permeability of the fabrics obtained in the examples or comparative examples was evaluated. Air permeability was determined according to JIS L1096-2010, the Frazier method (Method A). The fabrics were measured three times, and the average value was used for evaluation in four stages according to the following criteria.

[0120] A: Less than 0.7 cc

[0121] B: 0.7 cc or more but less than 1.0 cc

[0122] C: 1.0 cc or more but less than 1.3 cc

[0123] D: 1.3 cc or more

[0124] Set A and B as qualified.

[0125] J. Evaluation of textile products

[0126] (a) Fracture strength

[0127] The bursting strength was determined according to JIS L1096-2020 - Bursting Strength, Mullen Method (Method A). The fabric was measured three times, and the average value was used for evaluation in four stages based on the following criteria.

[0128] (For fabrics where the yarn content is less than 50 dtex)

[0129] A: Above 240 kPa,

[0130] B: Above 210 kPa and below 240 kPa

[0131] C: Above 180 kPa and below 210 kPa

[0132] D: Less than 180 kPa

[0133] Set A and B as having acceptable fracture strength.

[0134] (For cases where the raw yarn supplied for knitting is 50 dtex or higher)

[0135] A: Above 300 kPa,

[0136] B: Above 280 kPa and below 300 kPa

[0137] C: Above 260 kPa and below 280 kPa

[0138] D: Less than 260 kPa

[0139] Set A and B as having acceptable fracture strength.

[0140] (b) Wear intensity

[0141] Wear strength was measured on the fabric according to JIS L1096-2020 - Wear Strength, Steel Blade Method (F-1 Method). Five measurements were performed, and the fabric was evaluated in four stages based on the average rotational speed at which holes appeared, according to the following criteria.

[0142] A: 10,000 RPM or higher

[0143] B: 8000 RPM or higher but less than 10000 RPM

[0144] C: 6000 RPM or higher but less than 8000 RPM

[0145] D: Below 6000 RPM

[0146] Set A and B as having acceptable wear strength.

[0147] (c) Durability

[0148] Durability is evaluated using (a) fracture strength and (b) abrasion strength, in accordance with the following table.

[0149] [Table 2]

[0150] Table 2

[0151]

[0152] Set A and B as having acceptable durability.

[0153] (d) Softness

[0154] For the knitted fabric, 40 dtex, 24 filament nylon 6 multifilament was used. Based on the lace knitted fabric manufactured using the same method as in Example 1, the softness was relatively evaluated by five inspectors with extensive hand feel evaluation experience. The results were calculated by averaging the scores from each inspector, rounding to the nearest decimal. An average of 5 was designated A, an average of 4 B, an average of 3 C, and an average of 1-2 D.

[0155] 5 points: Excellent

[0156] 4 points: Slightly better

[0157] 3 points: Average

[0158] 2 points: Slightly poor

[0159] 1 point: poor

[0160] Set A and B as having acceptable softness.

[0161] [Example 1]

[0162] (Manufacturing of polyamide multifilament)

[0163] Core-sheath type polyamide multifilament

[0164] The core component uses polyamide 6 (melt viscosity: 1500 poise, relative viscosity of sulfuric acid: 3.3, melting point: 225℃, titanium dioxide 0.02% by mass).

[0165] The sheath component uses polyamide 6 (melt viscosity: 500 poise, relative viscosity of sulfuric acid: 2.2, melting point: 225℃, titanium dioxide 0.02% by mass).

[0166] Adjust the moisture regain of each fragment to less than 0.03% by mass, and then put them into... Figure 1 In the spinning machine shown, the yarn is melted at a spinning temperature of 270°C, from which... Figure 2 The polyamide multifilament 100 is designed with a fiber cross-section having a core 11 and a sheath 12, and a spinning die 1 with 80 holes and a diameter of 0.20 mm, so that the core / sheath ratio is 80 / 20. The spun yarn is cooled and solidified by blowing cold air through a cooling device 2, and after being oiled by an oil supply device 3, it is interlaced by a fluid interlacing nozzle device 4. The circumferential speed (traction speed) of the traction roller 5 with a surface temperature of 25°C is set to 1600 m / min (set value). Then, the yarn pulled by the traction roller 5 is pulled by an extension roller 6 with a surface temperature of 155°C, and extended at an extension ratio of 2.0 between the rollers (between roller 5 and roller 6). It is then wound by a winding machine 7 with a winding speed of 4000 m / min (set value) to obtain a core-sheath type polyamide multifilament with two 56 dtex-40 filaments. The fineness, tensile strength, crystallinity, and amide orientation parameters of the obtained polyamide multifilaments were evaluated. The results are shown in Table 3.

[0167] (Fabric manufacturing)

[0168] The obtained 1000 multifilaments were warped and wound onto a warp beam. The yarn wound on the warp beam was then sized or dried to prepare the warp yarns. Subsequently, the obtained multifilaments were driven into the weft yarns through the shuttle of a water-jet loom to weave a plain weave fabric. The woven fabric was then scourted, heat-set (intermediate setting) at 170°C, dyed, and calendered at 170°C to obtain the fabric for a rain jacket. The evaluation results of the obtained fabric are shown in Table 3.

[0169] (The manufacture of woven items)

[0170] The obtained multifilament yarns were warped with 576 strands and wound onto a warp beam. The yarn wound on the warp beam was aged to prepare the warp yarns. Then, using a 28G Raschel knitting machine, the fabric was woven with an elastic mesh structure, using a mixture of 77% of the obtained multifilament yarns and 23% of 156 dtex polyurethane. Next, the greige fabric was scouring, dyeing, and finishing at 180°C to obtain a Raschel knitted fabric for underwear. The evaluation results of the obtained fabric are shown in Table 3.

[0171] [Table 3]

[0172]

[0173] [Examples 2-6, Comparative Examples 1-4]

[0174] The polymer composition was changed as shown in Table 3, except that polyamide multifilaments, fabrics, and knitted fabrics were obtained using the same method as in Example 1. Furthermore, in Comparative Example 4, instead of polyamide 6 used in the sheath composition of Example 1, a copolyamide (melt viscosity: 500 poise, relative viscosity of sulfuric acid: 2.2, melting point: 225°C, titanium dioxide 0.02% by mass) was used. The evaluation results are shown in Table 3.

[0175] [Example 7, Comparative Example 5]

[0176] The traction speed and winding speed were varied as shown in Table 4, and the ratio was corrected by a stretch of 45%. Otherwise, polyamide multifilaments were obtained using the same method as in Example 1. The evaluation results are shown in Table 4.

[0177] [Example 8, Comparative Example 6]

[0178] The concentration (addition rate) of the additives for the sheath component was varied as shown in Table 4. Otherwise, polyamide multifilaments, fabrics, and knitted fabrics were obtained using the same method as in Example 1. The evaluation results are shown in Table 4.

[0179] [Example 9, Comparative Example 7]

[0180] The temperature of the extension front roller (the surface temperature of the traction roller 5) was changed as shown in Table 4. Otherwise, polyamide multifilaments, fabrics, and knitted fabrics were obtained using the same method as in Example 1. The evaluation results are shown in Table 4.

[0181] [Examples 10 to 12]

[0182] The total fineness and filament count (fineness and yarn structure) were varied as shown in Table 4. Otherwise, polyamide multifilaments, fabrics, and knitted fabrics were obtained using the same method as in Example 1. The evaluation results are shown in Table 4.

[0183] [Table 4]

[0184]

[0185] [Comparative Example 8]

[0186] Individual yarns of 56 dtex-18 filaments were obtained using the conditions and methods shown in Table 5. Additionally, fabrics and knitted products were obtained using the same methods as in Example 1. The evaluation results are shown in Table 5.

[0187] [Comparative Example 9, Comparative Example 10]

[0188] Individual yarns of 56 dtex-40 filaments were obtained using the conditions and methods shown in Table 5. In Comparative Examples 9 and 10, polyamide multifilaments with different strength-elongation characteristics were obtained by varying the traction speed. Furthermore, fabrics and knitted fabrics were obtained using the same methods as in Example 1. The evaluation results are shown in Table 5.

[0189] [Table 5]

[0190] Table 5

[0191]

[0192] [Example 13]

[0193] Core-sheath type polyamide multifilament

[0194] The core component uses polyamide 6 (melt viscosity: 1500 poise, relative viscosity with sulfuric acid: 3.3, melting point: 225℃, titanium dioxide 0.02%).

[0195] The sheath is composed of polyamide 6 (melt viscosity: 500 poise, relative viscosity of sulfuric acid: 2.2, melting point: 225℃, titanium dioxide 0.3%).

[0196] Adjust the moisture regain of each fragment to less than 0.03% by mass, and then put them into... Figure 1 In the spinning machine shown, the yarn is melted separately at a spinning temperature of 270°C, from which it becomes... Figure 2The spinning die, designed with a 72-hole nozzle diameter (0.20 mm), was used to achieve a core / sheath ratio of 80 / 20. The spun yarn was cooled and solidified by blowing cold air through cooling device 2, and then oiled by oil supply device 3. Interlacing was then initiated through fluid interlacing nozzle device 4, and traction was performed with the circumferential speed (traction speed) of traction roller 5 set to 2000 m / min (set value). Subsequently, the yarn pulled by traction roller 5 was stretched between rollers (between rollers 5 and 6) at an extension ratio of 1.75 using extension roller 6 with a surface temperature of 155°C. The yarn was then wound on a winding machine 7 with a winding speed set to 3500 m / min (set value) to obtain two 41 dtex-36 filament core-sheath type polyamide multifilaments as POY. The fineness, tensile strength, crystallinity, and amide orientation parameters of the obtained POY were evaluated. The results are shown in Table 6.

[0197] (The manufacture of DTY)

[0198] The obtained POY is subjected to extended friction false twisting using a three-axis friction-type friction disc extended friction false twisting device. It is fed from a feed roller at a circumferential speed of 550 m / min to a contact-type false twisting heater heated to 170°C, resulting in an extension of 1.5 times, with a disc rotation speed of 7500 rpm and a disc diameter of... 51. A D / Y ratio of 2.18 and a false twist coefficient of 30000 were used to extend and simultaneously perform false twisting to obtain 33 dtex-36 filament DTY (D: feed roller speed (m / min), Y: disc rotation speed (m / min)). The fineness, tensile strength, crystallinity, and amide orientation parameters of the obtained DTY were evaluated. The results are shown in Table 6.

[0199] (Fabric manufacturing)

[0200] The obtained 1000 multifilaments were warped and wound onto a warp beam. The yarn wound on the warp beam was then sized or dried to prepare the warp yarns. Subsequently, the obtained multifilaments were driven into the weft yarns through the shuttle of a water-jet loom to weave a plain weave fabric. The woven fabric was then scourted, heat-set (intermediate setting) at 170°C, dyed, and calendered at 170°C to obtain the fabric for a rain jacket. The evaluation results of the obtained fabric are shown in Table 6.

[0201] (The manufacture of woven items)

[0202] The obtained multifilament yarns were warped with 576 strands and wound onto a warp beam. The yarn wound on the warp beam was aged to prepare the warp yarns. Then, using a 28G Raschel knitting machine, the fabric was woven with an elastic mesh structure, using a mixture of 77% of the obtained multifilament yarns and 23% of 140 dtex polyurethane. Next, the greige fabric was scouring, dyeing, and finishing at 180°C to obtain a Raschel knitted fabric for underwear. The evaluation results of the obtained fabric are shown in Table 6.

[0203] [Example 14, Comparative Example 11]

[0204] The traction speed and winding speed were varied as shown in Table 6, and the magnification was corrected so that the elongation of POY was 65%. Otherwise, polyamide multifilaments, fabrics, and knitted fabrics were obtained using the same method as in Example 13. The evaluation results are shown in Table 6.

[0205] [Example 15, Example 16]

[0206] The total fineness and filament count were varied as shown in Table 6, except that polyamide multifilaments, fabrics, and knitted fabrics were obtained using the same method as in Example 13. The evaluation results are shown in Table 6.

[0207] [Table 6]

[0208] Table 6

[0209]

[0210] [Comparative Example 12]

[0211] Individual yarns of 41 dtex-10 filaments were obtained using the conditions and methods shown in Table 7. Additionally, fabrics and knitted products were obtained using the same methods as in Example 13. The evaluation results are shown in Table 7.

[0212] [Comparative Example 13, Comparative Example 14]

[0213] Individual yarns of 41 dtex-36 filaments were obtained using the conditions and methods shown in Table 7. In Comparative Examples 13 and 14, polyamide multifilaments with different strength-elongation characteristics were obtained by varying the traction speed and winding speed. Furthermore, fabrics and knitted fabrics were obtained using the same methods as in Example 13. The evaluation results are shown in Table 7.

[0214] [Table 7]

[0215] Table 7

[0216]

[0217] Industrial availability

[0218] The polyamide multifilament of the present invention provides a polyamide multifilament with fine single yarn fineness, high tensile strength-to-elongation product, and excellent abrasion resistance. Furthermore, it provides a fabric with excellent tear strength, abrasion resistance, and air permeability, as well as a knitted fabric with excellent bursting strength, abrasion resistance, and softness using the polyamide multifilament of the present invention.

[0219] The invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes or modifications may be made without departing from the spirit and scope of the invention.

[0220] This application is based on Japanese patent application filed on March 23, 2023 (Japanese Patent Application No. 2023-46260), the contents of which are incorporated herein by reference.

[0221] Explanation of icon numbers

[0222] 1: Spinning die opening

[0223] 2: Cooling device

[0224] 3: Oil supply device

[0225] 4: Fluid Interlacing Nozzle Device

[0226] 5: Traction roller

[0227] 6: Extension Roller

[0228] 7: Winding device (winding machine)

[0229] 11: Core

[0230] 12: Sheath

[0231] 100: Polyamide multifilament

Claims

1. A polyamide multifilament comprising core-sheath type composite profile polyamide fiber, wherein the crystallinity of the sheath is less than 35%, the single yarn fineness is less than 3.0 dtex, and the tensile strength product is greater than 5.

5.

2. The polyamide multifilament according to claim 1, wherein, The amide orientation parameter of the core of the core-sheath type composite profile polyamide fiber is 1.5 or higher.

3. A woven fabric, a portion of which comprises polyamide multifilament as described in claim 1 or 2.

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