Polyamide multifilament yarn, method for manufacturing the same and braid

Abstract

A polyamide multifilament is provided, having a strength of 7.0 cN / dtex or higher, an elongation of 33-50%, a total fineness of 56 dtex or less, and a fuzziness and looseness of less than 1 per 100,000 m. This provides a high-strength polyamide multifilament with appropriate elongation and suppressed fuzziness and looseness. Furthermore, the polyamide multifilament of this invention provides a woven fabric with softness and lightweight feel, high passability and excellent product quality and durability.

Description

Technical Field

[0001] This invention relates to polyamide multifilament. More specifically, it relates to a high-strength polyamide multifilament that, when used in woven fabrics, provides a thin (thin) woven fabric with excellent softness, lightweight feel, and durability. Background Technology

[0002] Polyamide fiber, as a synthetic fiber, is widely used in clothing applications such as underwear and outdoor jackets due to its unique softness, high strength, excellent color development during dyeing, heat resistance, and moisture absorption.

[0003] With global warming in recent years, the demand for functional underwear has increased, leading to a desire to improve the hand feel of underwear fabrics and make them thinner. Additionally, the growing popularity of outdoor sports has created a need for lighter and thinner sportswear fabrics. Along with this trend towards thinner fabrics, polyamide multifilaments are becoming increasingly finer in both finer and single-filament fibers. However, this also results in reduced durability, leading to a desire to improve the hand feel and achieve a lighter feel while maintaining the same level of durability.

[0004] For example, in Patent Document 1, by adding stretching rollers for multi-stage stretching, high-ratio stretching can be achieved without producing fuzz, resulting in high-strength polyamide multifilament. Using this high-strength polyamide multifilament, a lace (lace) woven fabric is provided that maintains high throughput, product quality, and durability, while the transparency of the lace thread makes the pattern look beautiful and has an excellent feel.

[0005] Furthermore, in Patent Document 2, by providing a heating cylinder at the spinning section to preferentially mitigate polymer orientation and by performing a stretching process with low spinning speed and high stretching ratio during a stretching phase, a crystal structure is effectively constructed, resulting in a high-strength polyamide multifilament with an appropriate fiber modulus. Using this high-strength polyamide multifilament, a lace knit fabric and stockings (pantyhose) are provided that maintain high passability, product quality, and durability while exhibiting a beautiful pattern and excellent hand feel due to the transparency of the lace thread.

[0006] Prior art literature

[0007] Patent Document 1: International Publication No. 2019 / 146600

[0008] Patent Document 2: International Publication No. 2018 / 021011 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in the method described in Patent Document 1, high strength is achieved by performing high-ratio stretching, resulting in an elongation of 23-33%, which is relatively low for clothing applications. The fiber modulus is high, and the high passability in the manufacturing process of woven fabrics still suffers from a significant reduction due to processing conditions.

[0011] Furthermore, in the method described in Patent Document 2, the interlacing is applied with a low interlacing (entanglement) strength before stretching in order to achieve effective stretching. Therefore, it is easy for the interlacing to untwist through a high-ratio stretching, resulting in fuzziness and looseness, which will be explained in detail later. As a result, there are problems such as poor high-passability in the manufacturing process of woven fabrics and the formation of stripes, which degrade the product quality.

[0012] This invention addresses the aforementioned problems. As woven fabrics become thinner, the fineness of fibers and monofilaments continues to increase. Therefore, the objective of this invention is to provide a polyamide multifilament with high strength, appropriate elongation, and suppressed fuzz and looseness. More specifically, the polyamide multifilament of this invention provides a woven fabric with softness and lightweight feel, high passability, and excellent product quality and durability.

[0013] Methods for solving problems

[0014] To solve the above problems, the present invention is constructed using the following technology.

[0015] (1) A polyamide multifilament, characterized in that it has a strength of 7.0 cN / dtex or more, an elongation of 33 to 50%, a total fineness of 56 dtex or less, and a number of hairy or loose fibers of less than 1 per 100,000 m.

[0016] (2) The polyamide multifilament described in (1) above is characterized in that the dry heat shrinkage rate at 180°C is less than 12.0%.

[0017] (3) A woven fabric in which a portion uses the polyamide multifilament described in (1) or (2).

[0018] (4) A method for manufacturing polyamide multifilament, which employs a direct spinning and stretching method as follows: melting polyamide resin, cooling and solidifying each filament extruded from the spinning head, performing oiling and interlacing treatments, stretching, heat-treating, and winding using rollers with different circumferential speeds, wherein the manufacturing method is a method for manufacturing the polyamide multifilament described in (1), characterized in that the following conditions (A) to (D) are satisfied:

[0019] (A) The degree of interlacing before stretching is 20 to 50. (B) The stretching ratio is 3.0 to 3.5. (C) The heat setting temperature is above 35°C and below 15°C below the melting point of the polyamide resin. (D) The winding tension between the stretching roller and the winding device is 0.15 to 0.20 cN / dtex.

[0020] The effects of the invention

[0021] The polyamide multifilament of the present invention has high strength, appropriate elongation, and suppresses fuzzing and loosening. Furthermore, the polyamide multifilament of the present invention provides a woven fabric with softness and lightweight feel, high passability, and excellent product quality and durability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating one embodiment of a manufacturing apparatus that can be preferably used in the method for manufacturing polyamide multifilaments according to the present invention. Detailed Implementation

[0023] The present invention will now be described in more detail.

[0024] The polyamide multifilament constituting the present invention is a high molecular weight resin composed of so-called hydrocarbon groups linked to the main chain via amide bonds. This polyamide exhibits excellent fiber-forming properties and mechanical characteristics. It is preferably composed primarily of polyhexamethylene amide (nylon 6) and polyhexamethylene adipamide (nylon 66), with nylon 6 being more preferred due to its resistance to gelation and good fiber-forming properties. The phrase "primarily composed of" refers to the presence of 80 mol% or more of the ε-caprolactam unit constituting polyhexamethylene amide and the adipate hexamethylene adipamide unit constituting polyhexamethylene adipamide, more preferably 90 mol% or more. Other components are not particularly limited; examples include aminocarboxylic acid, dicarboxylic acid, and diamine units that constitute monomers of polydodecanoamide, polyhexamethylene adipamide, polyhexamethylene azelaic acid, polyhexamethylene adipamide, polyhexamethylene adipamide, polyhexamethylene adipamide, polyhexamethylene adipamide, polyhexamethylene adipamide, polyhexamethylene terephthalamide, and polyhexamethylene isophthalamide.

[0025] Furthermore, to effectively realize the effects of the present invention, it is preferable that the polyamide does not contain any additives such as matting agents represented by titanium dioxide, but additives may be included as needed within a range that does not hinder the effects of heat-resistant agents, etc. Additionally, the content of these additives may be mixed between 0.001 and 0.3% by weight relative to the polymer, as needed.

[0026] The total fineness, strength, elongation, and number of hairs and loose strands per 100,000 m of the polyamide multifilament of the present invention are all within the above-mentioned range. That is, while a softness and lightweight feel can be obtained by refining the total fineness, durability deteriorates. On the other hand, since durability is proportional to the total fineness and the fineness of the monofilaments, it is necessary to increase the strength in order to simultaneously satisfy softness, lightweight feel, and durability, and to set an appropriate elongation rate in order to maintain high throughput and product quality. In addition, it is necessary to suppress the generation of hairs and loose strands in order to improve high throughput and product quality. Therefore, the inventors have conducted in-depth research and discovered an appropriate range of fineness, strength, elongation, and number of hairs and loose strands for a woven fabric that can achieve excellent high throughput, product quality, product durability, and also excellent softness and lightweight feel.

[0027] The polyamide multifilament of the present invention is characterized by a total fineness of 56 dtex or less. By setting it to this range, the woven fabric exhibits excellent softness and lightweight feel. More preferably, it is 44 dtex or less.

[0028] The polyamide multifilament of the present invention has a strength of 7.0 cN / dtex or higher. By setting it within this range, the durability of the woven fabric reaches a level suitable for practical use. Furthermore, higher strength is better, but in the present invention, its upper limit is approximately 8.0 cN / dtex.

[0029] The elongation of the polyamide multifilament of the present invention is 33-50%. By setting it within this range, filament breakage in higher processing steps is reduced, and high-speed passability and product quality are improved. High-speed passability is particularly excellent during high-speed weaving and knitting. When the elongation is less than 33%, filament breakage increases in higher processing steps such as fabric manufacturing processes (warping and weaving) and woven fabric manufacturing processes (warping and knitting), resulting in poor high-speed passability. The dimensional stability of the woven fabric decreases, and product quality deteriorates. If the elongation exceeds 50%, the strength decreases, and the durability (breaking strength, tear strength) of the woven fabric decreases. A more preferred elongation is 35-45%.

[0030] The polyamide multifilament of this invention has fewer than one fuzzy or loose strand per 100,000 m. If there is more than one, the fuzzy or loose strands will get caught on the reed, needles, etc., during the weaving and knitting processes, leading to increased yarn breakage and poor high-pass permeability. In addition, the tension changes caused by the fuzzy or loose strands getting caught on the reed or needles will cause stripe defects, resulting in poor product quality.

[0031] The dry heat shrinkage rate of the polyamide multifilament of the present invention at 180°C is preferably 12.0% or less. 180°C is a general temperature required for dimensional stabilization and shaping of woven fabrics using polyamide multifilament. The dry heat shrinkage rate at this temperature represents the degree of shrinkage of the filaments generated during the fabric manufacturing process. By keeping it below 12.0%, dimensional stability of the woven fabric can be obtained, and the disadvantage of uneven shrinkage can be suppressed.

[0032] There is no particular limitation on the cross-sectional shape of the polyamide multifilament of the present invention. For example, it can be a circular cross-section, a flat cross-section, a lens-shaped cross-section, a multi-leaf cross-section, a hollow cross-section, and other known irregular cross-sections.

[0033] The polyamide multifilament of the present invention preferably has a filament number of 3 or more. The upper limit is preferably 144 or less when the total fineness is 56 dtex, and preferably 27 or less when the total fineness is 11 dtex.

[0034] The polyamide multifilament of the present invention preferably has a single filament fineness of 0.4 to 10 dtex. The finer the single filament fineness, the more soft the woven fabric for clothing becomes; however, on the other hand, pilling is more likely to occur due to friction, which reduces the durability of the product. By setting it within this range, woven fabrics with excellent softness and durability can be obtained.

[0035] The following is a detailed description of an example of a method for manufacturing polyamide multifilaments according to the present invention. Figure 1 This describes one embodiment of a manufacturing apparatus employing a direct spinning and drawing method preferred in the manufacturing method of the polyamide multifilament of the present invention. In the polyamide multifilament of the present invention, polyamide resin is melted, the polyamide polymer is metered and conveyed using a gear pump, and finally extruded from an outlet provided on a spinning head 1 to form individual filaments. For example... Figure 1 As shown, to suppress contamination of the filaments ejected from the spinning head 1 over time, a gas supply device 2 for spraying steam is provided. For slow cooling, a multi-layered heating cylinder 3 is arranged around the entire circumference. A cooling device 4 cools and solidifies the filaments to room temperature. Then, an oiling agent is applied using an oiling device 5, and the filaments are bundled together to form a multifilament. This multifilament is then interwoven using a fluid interlacing nozzle device 6, passing through the traction roller 7 and the stretching roller 8, while being stretched according to the speed ratio of the traction roller 7 to the stretching roller 8. Furthermore, the filaments are heat-treated by heating the stretching roller 8 and then wound up using a winding device 9.

[0036] The polyamide multifilament of the present invention is preferably manufactured by the following method: setting the relative viscosity of the sulfuric acid in the polyamide polymer used for melt spinning to 2.5 to 4.0, making the melt spinning temperature higher than 20°C and lower than 85°C relative to the melting point of the polyamide, and setting the temperature of the gas supply device and the heating cylinder to 250°C or higher in order to maintain the atmosphere temperature under the nozzle at a high temperature, and setting the cooling start distance LS to 100 to 180 mm by blowing compressed air. To impart bundle properties, the pre-stretch cross-linking degree (CF value) is set to 20–50, the traction roller speed is set to 700–1500 m / min, and the stretching ratio is set to 3.0–3.5 times. To fix the highly oriented crystalline structure resulting from stretching, heat setting is performed at a temperature 35°C or more but less than 15°C below the polymer melting point. To ensure good separation between the stretching roller and the filament and to suppress fuzz and looseness, the tension between the stretching roller and the winding device (winding tension) is set to 0.15–0.20 cN / dtex.

[0037] In the manufacture of the polyamide multifilament of the present invention, the relative viscosity of the polyamide resin with sulfuric acid is preferably 2.5 to 4.0. By setting it within this range, high-strength polyamide multifilaments can be obtained.

[0038] In the manufacture of the polyamide multifilament of the present invention, a heating cylinder 3 is provided above the cooling device 4, surrounding each filament in a circumferential manner. By placing the heating cylinder 3 above the cooling device 4, the temperature of the gas supply device and the atmosphere inside the heating cylinder is maintained at 250°C or higher, thereby allowing for the gentle orientation of the polyamide polymer extruded from the spinning head 1. This gentle orientation, achieved through slow cooling from the nozzle surface to the cooling chamber, results in multifilaments with high strength. Without the heating cylinder, the gentle orientation achieved through slow cooling from the nozzle surface to the cooling chamber is insufficient, making it difficult to obtain fibers with sufficient strength.

[0039] In the manufacture of the polyamide multifilament of the present invention, the cooling device 4 can be a cooling device that blows cooling and rectifying air from a certain direction, or an annular cooling device that blows cooling and rectifying air from the outer periphery to the center, or an annular cooling device that blows cooling and rectifying air from the center to the outer periphery, etc., any of these methods can be used. The vertical distance LS (cooling start distance LS) from the lower surface of the spinning head to the upper end of the cooling air blowing part of the cooling device 4 is preferably in the range of 100 to 180 mm. By making the cooling start distance LS 100 mm or more, it is possible to promote gentle orientation and obtain fibers with sufficient strength; by making the cooling start distance LS 180 mm or less, it is possible to suppress yarn wobbling and ensure productivity. More preferably, it is 110 to 170 mm.

[0040] In the manufacture of the polyamide multifilament of the present invention, the bundled properties of the traveling multifilament before the traction roller 7 are improved. By sufficiently imparting bundled properties, untwisting of the bundled multifilament can be suppressed even after stretching, resulting in good filament separation from the stretching roller 8. This not only suppresses fuzz and looseness but also prevents filament breakage caused by the stretching roller being wound up. In particular, the finer the total fineness, the more necessary it is to appropriately reduce the tension, as filaments are easily wound up by the stretching roller 8, easily generating fuzz and looseness. To improve bundled properties, a fluid interlacing nozzle device 6 is used to impart interlacing, controlling the interlacing degree (CF value) before stretching to be between 20 and 50. The interlacing degree referred to here is measured using an automatic interlacing degree testing machine (Rothschild ENTANGLEMENTTESTERR-2040) with performance equivalent to the method described in JIS L1013, on a sample of multifilament collected by winding the traveling multifilament on the traction roller 7. Specifically, the measurement speed was 2.5 m / min, the trip tension level was 1.2 cN / dtex, the filament length from the tripping point to the next needle insertion was 20 mm, and the measurement was repeated 50 times, with continuous measurement performed on the sample. The open fiber length (mm) from the needle insertion point of the test filament to the tripping tension level (1.2 cN / dtex) was measured. The value obtained by dividing 50000 (mm) by the sum of the open fiber lengths (mm) measured in the 50 trippings was taken as the interlacing degree (number of interlacings per 1 m).

[0041] To control the interlacing degree within this range, the design of the fluid interlacing nozzle device and the method of controlling the fluid ejection pressure in the fluid interlacing nozzle device are useful. For example, by setting the ejection pressure to 0.3 to 0.4 MPa, the interlacing degree can be controlled between 20 and 50. By setting the interlacing degree to 20 or higher, the bundle cohesion increases, the filament peeling from the stretching roller is improved, and fuzz and looseness are suppressed, with the number of fuzz and looseness per 100,000 m being less than 1. In addition, filament breakage due to being wound up by the stretching roller is suppressed. By setting the interlacing degree to 50 or lower, damage caused by the interlacing compressed air is reduced, especially since the finer the total fineness and the finer the single filament fineness, the greater the damage to the filament. Therefore, by suppressing the reduction in strength, the strength reaches 7.0 cN / dtex. In addition, filament breakage due to damage caused by compressed air pressure is suppressed. More preferably, it is 30 to 45.

[0042] In the manufacture of polyamide multifilament of the present invention, stretching is preferably performed in one stage. When the elongation is 33-50%, it can be appropriately adjusted by the stretching ratio. However, by reducing the fineness of the single filament and performing one-stage stretching, friction between the traveling multifilament and the stretching roller under low tension can be suppressed, preventing damage to the filament and preventing a decrease in strength.

[0043] Therefore, in this invention, in order to achieve a specified strength of 7.0 cN / dtex or higher, an elongation of 33-50%, and less than one instance of fuzz or looseness per 100,000 m, the appropriate draw ratio in a single stretching stage is preferably 3.0 to 3.5 times. A draw ratio of 3.0 times or higher yields high strength, while a draw ratio of 3.5 times or less yields polyamide multifilaments with appropriate elongation and suppressed fuzz and looseness. A draw ratio of 3.1 to 3.4 times is preferred.

[0044] In the manufacture of the polyamide multifilament of the present invention, the heat setting process is performed by bringing the filament into contact with a heating element after stretching. Taking the direct spinning stretching method as an example, it is preferable to use a method in which a heater is provided inside the stretching roller, and the filament held (in contact) by the stretching roller is heat-set. The heat setting temperature (temperature of the stretching roller) is preferably a temperature at least 35°C lower than the melting point of the polyamide resin and a temperature at least 15°C lower than the melting point of the polyamide resin. For example, when the melting point of the polyamide resin used in the polyamide multifilament of the present invention is 225°C, the heat setting temperature is 190°C ≤ 210°C.

[0045] By setting a temperature 35°C or higher below the melting point of the polyamide resin, the fiber crystal structure can be sufficiently fixed, achieving a strength of 7.0 cN / dtex and a dry heat shrinkage rate of less than 12.0% at 180°C. Furthermore, after winding, the winding is tightened to suppress multifilament shrinkage, preventing the product from being unable to be pulled off the take-up roller.

[0046] By setting the temperature to 15°C or less below the melting point of the polyamide resin, the friction of the polymer can be suppressed, ensuring the separation of the traveling multifilament from the stretching roller, suppressing fuzz and looseness, with the number of fuzz and looseness per 100,000 m being less than 1.

[0047] In the manufacture of polyamide multifilament of the present invention, the winding tension between the stretching roller 8 and the winding device 9 is 0.15 cN / dtex or higher. As a method to control the tension between the stretching roller 8 and the winding device 9 within this range, controlling the ratio of the circumferential speed of the stretching roller 8 to the winding roller (not shown) within the winding device is useful. Although it also depends on the total fineness and draw ratio, the tension can be adjusted to this range by setting the ratio of the stretching roller circumferential speed to the winding roller circumferential speed to 1.02 to 1.08. By setting the winding tension to 0.15 cN / dtex or higher, the separation of the traveling multifilament from the stretching roller 8 can be ensured, reducing the likelihood of fuzz and looseness, with fewer than one fuzz or looseness per 100,000 m. Furthermore, the upper limit of the winding tension in the present invention is 0.20 cN / dtex. Exceeding this value may result in residual polymer strain stress, causing multifilament shrinkage and tight winding on the winding roller, making it impossible to pull the product roller from the winding roller, thus preventing production. In particular, the finer the total fineness, the easier it is to wind the yarn on the stretching roller 8, the worse the unwinding property becomes, and the more likely it is to produce fuzz and looseness. Therefore, it is very important to control it within this range.

[0048] The polyamide multifilaments of the present invention can be woven and fabricated using conventional methods.

[0049] The knitting pattern can be any of the following: warp-knitted fabric (e.g., tricot, raschel), circular knitted fabric (e.g., single circular, double circular, shaped circular, or shaped horizontal knit). Additionally, the knitting structure can be any of the following: warp-knitted fabric (e.g., half-needle, half-backstitch, modified warp-chain knit, satin, satin mesh, elastic mesh, tricot mesh, or other variations); or circular knitted fabric (e.g., plain knit, plain double-sided, rib, double rib, reverse stitch, or other variations). These can be used without particular limitation.

[0050] In the above, the requirement is that the fabric be both thin and durable, and the fineness range of 33 dtex or above is required to achieve the practical durability of general Raschel warp-knitted fabrics.

[0051] For fabric weaving, you can appropriately choose common fabric structures such as plain weave, twill weave, satin weave, yarn or gauze, garter weave, multi-arm weave, jacquard weave, etc.

[0052] The above requires both thinness and durability of the fabric, and the fineness range of 11 dtex or higher is required to achieve practical durability for general plain weave fabrics.

[0053] The polyamide multifilament of the present invention is used in the form of raw silk for weaving. Furthermore, the dyeing, subsequent post-processing, and final setting conditions after the fabric is made can be carried out according to known methods. As the dye, acid dyes and reactive dyes can be used, and there are no limitations on the color, etc.

[0054] The polyamide multifilament of this invention, by appropriately selecting the fabric structure, can be used as clothing material for women's close-fitting underwear, camisoles, petticoats, shorts, tights, panties, T-shirts, U-neck shirts, round neck shirts, jumpsuits, waistbands, etc.; men's close-fitting T-shirts, U-neck shirts, round neck shirts, running shirts, shorts, tights, briefcases, etc.; sportswear running shirts and shorts, competition shirts and shorts, golf shirts, tennis shirts, cycling shirts and shorts, T-shirts, polo shirts, outdoor shirts, baseball underwear, training clothes, tights, swimwear, sports underwear, ski underwear, speed skating clothing, etc.; and general outerwear sweaters, vests, etc.; in addition, as a material, it can be used for gloves, protective gear, sweatbands, linings, etc.

[0055] Example

[0056] The present invention will be described in more detail below through embodiments.

[0057] A. Strength, elongation

[0058] Tensile strength and elongation of fiber samples were determined according to JIS L1013 (2010). The test conditions were a constant-speed tension testing machine with a clamp spacing 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 was less than the maximum strength.

[0059] Strength and tensile strength product are calculated using the following formula.

[0060] Strength = Strength at cut (cN) / Fineness (dtex)

[0061] Elongation = Elongation at cut (%)

[0062] B. Fineness

[0063] The fiber sample was placed on a measuring tape with a rotation speed of 1.125 m / s and rotated 500 times to form a looped skein. After drying in a hot air dryer (105±2℃×60 minutes), the mass of the skein was weighed using a balance, and the fineness (dtex) was calculated by multiplying the mass by the standard moisture content. The standard moisture content was 4.5%.

[0064] C. Relative viscosity of sulfuric acid (ηr)

[0065] 0.25 g of polyamide chip or fiber sample was dissolved in 100 ml of 98% by mass sulfuric acid to obtain 1 g of solution. The flow time (T1) at 25°C was measured using an Ostwald viscometer. Next, the flow time (T2) of the 98% by mass sulfuric acid solution was measured only. The ratio of T1 to T2, T1 / T2, was taken as the relative viscosity of the sulfuric acid.

[0066] D. Number of feathers and loose pieces

[0067] The obtained fiber sample was wound back at a speed of 500 m / min. A laser-type fuzz detector was set up 2 mm away from the filaments in the winding. The total number of defects detected was converted into the number of defects per 100,000 m.

[0068] E. Dry heat shrinkage rate

[0069] The measurement was performed using a "Heat Shrinkage Unevenness Measurement Apparatus" manufactured by TORAY ENGINEERING. The yarn was continuously subjected to dry heat treatment in the section located between the yarn feed roller and the yarn lead-out roller, and the shrinkage rate caused by heat was continuously measured. The measurement was conducted for 3 minutes at a yarn feed speed of 10 m / min and a heater temperature of 180°C, and the average value was taken as the dry heat shrinkage rate (%).

[0070] F. Intersection before stretching

[0071] The sample collected by winding the traveling multifilament on the traction roller 7 is used as the object sample. Using an automatic interlacing degree tester (Rothschild ENTANGLEMENT TESTERR-2040) with performance equivalent to the method described in JIS L1013, the opening length (mm) from the needle-punched part of the test filament to the break-off tension level is measured and calculated under the following settings.

[0072] Measurement speed: 2.5 m / min

[0073] Breakout tension level 1.2cN

[0074] Thread length from the time of detachment to the next acupuncture: 20mm

[0075] Number of repeated measurements: 50

[0076] CF value = Total fiber opening length / 50000

[0077] G. Coiling tension

[0078] Using the TENSION METER and FT-R pickup sensors manufactured by TORAY ENGINEERING, the measurement was determined. Figure 1The tension between the stretching roller 8 and the winding device 9 shown is used as a value converted to unit fineness (cN / dtex).

[0079] H. Evaluation of Woven Products

[0080] (a) Process passability

[0081] The following criteria were used to evaluate the number of downtimes caused by yarn breakage when knitting 10 strands (1000m / s) in an elastic mesh structure using a Raschel warp knitting machine (No. 28) with a blend of 77% of the original yarn of the present invention and 23% of 140d polyurethane.

[0082] S: less than 2 times

[0083] A: More than 2 times but less than 4 times

[0084] B: 4 or more but less than 6 times

[0085] C: More than 6 times

[0086] S and A indicate that the process passes the test.

[0087] (b) Durability

[0088] Bursting strength was determined as an indicator of durability. Bursting strength of the woven fabric was measured according to JIS L1096 (2010)A method and the Mullen method. The test was performed three times, and the average value was used to evaluate the fabric in four levels according to the following criteria.

[0089] S: Above 300 kPa

[0090] A: Above 280 kPa and below 300 kPa

[0091] B: Above 260kPa and below 280kPa

[0092] C: Less than 260 kPa

[0093] S and A indicate that the durability is acceptable.

[0094] (c) Product Quality

[0095] The unevenness and stripe formation on every 50m of woven fabric are evaluated by visual inspection according to the following criteria.

[0096] S: No streaks or unevenness, with excellent quality.

[0097] A: Although it produces a few streaks or unevenness, it is not a problem for use as a product.

[0098] C: If it produces stripes or unevenness, it cannot be used as a product.

[0099] S and A indicate that the fabric has passed visual inspection.

[0100] I. Evaluation of Fabric Products

[0101] (a) Process passability

[0102] The following criteria were used to evaluate the number of downtimes caused by yarn breakage when a water jet loom was used to weave 10 plain weave fabrics (1000m / fabric) at a loom speed of 750 rpm and a weft yarn length of 1620 mm.

[0103] S: less than 2 times

[0104] A: More than 2 times but less than 4 times

[0105] B: 4 or more but less than 6 times

[0106] C: More than 6 times

[0107] S and A indicate that the process passes the test.

[0108] (b) Durability

[0109] Tear strength was determined as an indicator of durability. Tear strength was measured on the fabric according to JIS L1096 (2010) tensile strength, single-tongue method (Method A). The warp tear strength was measured three times, and the average value was used for a four-level evaluation based on the following criteria.

[0110] S: 6.0N or higher

[0111] A: 5.0N or higher but less than 6.0N

[0112] B: 4.0N or higher but less than 5.0N

[0113] C: Less than 4.0N

[0114] S and A indicate that the durability is acceptable.

[0115] (c) Product Quality

[0116] The unevenness and stripe formation on every 50m of fabric are evaluated by visual inspection according to the following criteria.

[0117] S: No streaks or unevenness, with excellent quality.

[0118] A: Although it produces a few streaks or unevenness, it is not a problem for use as a product.

[0119] C: If it produces stripes or unevenness, it cannot be used as a product.

[0120] S and A indicate that the fabric has passed visual inspection.

[0121] [Example 1]

[0122] (Manufacturing of polyamide multifilament)

[0123] As a polyamide, nylon 6 chips with a relative viscosity (ηr) of 3.3 and a melting point of 225°C were dried to a moisture content of less than 0.03% by mass using conventional methods. The resulting nylon 6 chips were melted at a spinning temperature (melting temperature) of 298°C and extruded from a spinneret (extrusion rate: 41.68 g / min). The spinneret used was a circular spinneret with 20 orifices, a diameter of φ0.25, and a nozzle diameter of 4 filaments / nozzle.

[0124] After exiting the spinning head, the filaments are cooled and solidified to room temperature by passing through a cooling device with cold air at 18°C. They are then oiled and bundled by an oil supply device, and cross-linked to a CF value of 35 by a fluid cross-linking nozzle device. The filaments are then stretched at a stretch ratio of 3.3 times by a traction roller (first guide roller: 1GD) at a speed of 1000 m / min and a stretching roller (second guide roller: 2GD) heated to 195°C. The winding speed is 3200 m / min, and the winding tension is 0.18 cN / dtex, resulting in 33 dtex, 5-filament nylon 6 multifilament. The evaluation results of the obtained nylon 6 multifilament are shown in Table 1.

[0125] (The manufacture of woven fabrics)

[0126] The obtained multifilament yarns were warped with 576 warps and wound onto a warp beam, allowing the yarns wound on the beam to age, thus preparing the warp yarns. Next, using a 28G Raschel warp knitting machine, the yarns were woven in an elastic mesh structure with a blend ratio of 77% of the obtained multifilament yarns and 23% of 140d polyurethane. The original fabric was then refined, dyed, and finally set at 180°C, thereby obtaining a Raschel knitted fabric for underwear. The evaluation results of the obtained knitted fabric are shown in Table 1.

[0127] [Examples 2 and 3] [Comparative Examples 1 and 2]

[0128] The interlacing degree before stretching was changed by adjusting the compressed air pressure as described in Tables 1 and 2. Otherwise, the same method as in Example 1 was used to obtain nylon 6 multifilament with a density of 33 dtex and 5 filaments. The evaluation results are shown in Tables 1 and 2.

[0129] [Example 4]

[0130] The feed rate was changed to 37.26 g / min, the stretch ratio was changed to 3.0, and the take-up speed was changed to 2950 m / min. Otherwise, the same method as in Example 1 was used to obtain 33 dtex, 5-filament nylon 6 multifilament. The evaluation results are shown in Table 1.

[0131] [Example 5]

[0132] The feed rate was changed to 42.32 g / min, the stretch ratio was changed to 3.5 times, and the take-up speed was changed to 3350 m / min. Otherwise, the same method as in Example 1 was used to obtain 33 dtex, 5-filament nylon 6 multifilament. The evaluation results are shown in Table 1.

[0133] [Comparative Example 3]

[0134] The feed rate was changed to 36.25 g / min, the stretch ratio was changed to 2.9 times, and the take-up speed was changed to 2870 m / min. Otherwise, the same method as in Example 1 was used to obtain 33 dtex, 5-filament nylon 6 multifilament. The evaluation results are shown in Table 2.

[0135] [Comparative Example 4]

[0136] The feed rate was changed to 43.33 g / min, the stretch ratio was changed to 3.6 times, and the take-up speed was changed to 3430 m / min. Otherwise, the same method as in Example 1 was used to obtain 33 dtex, 5-filament nylon 6 multifilament. The evaluation results are shown in Table 2.

[0137] [Example 6]

[0138] The winding speed was changed to 3180 m / min, and the winding tension was changed to 0.15 cN / dtex. All other things being done in the same manner as in Example 1, a 33 dtex, 5-filament nylon 6 multifilament was obtained. The evaluation results are shown in Table 1.

[0139] [Example 7]

[0140] The winding speed was changed to 3220 m / min, and the winding tension was changed to 0.20 cN / dtex. Otherwise, the same method as in Example 1 was used to obtain 33 dtex, 5-filament nylon 6 multifilament. The evaluation results are shown in Table 1.

[0141] [Comparative Example 5]

[0142] The winding speed was changed to 3160 m / min, and the winding tension was changed to 0.13 cN / dtex. All other things being done in the same manner as in Example 1, a 33 dtex, 5-filament nylon 6 multifilament was obtained. The evaluation results are shown in Table 2.

[0143] [Examples 8 and 9] [Comparative Examples 6 and 7]

[0144] The temperature of the stretching roller was changed as described in Table 1, and otherwise the same method as in Example 1 was used to obtain 33 dtex, 5 filament nylon 6 multifilament. The evaluation results are shown in Tables 1 and 2.

[0145] [Example 10]

[0146] The feed rate was changed to 49.84 g / min, a spinning head with 72 holes, circular shape, φ0.25 aperture, and 3 filaments / nozzle was used, the draw ratio was changed to 3.3 times, the temperature of the draw roller was changed to 200°C, the take-up speed was changed to 3100 m / min, and the take-up tension was changed to 0.16 g / dtex. All other things being done, the same method as in Example 1 was used to obtain 56 dtex, 24 filament Nylon 6 multifilament. The evaluation results are shown in Table 1.

[0147] [Comparative Example 8]

[0148] Using Patent Document 1 Figure 1 The process (two-stage stretching) was performed with an output weight of 41.86g. The first stage stretching was conducted with a circumferential speed ratio of 2.65 between the traction roller and the first stretching roller, and the second stage stretching was conducted with a circumferential speed ratio of 1.25 between the first stretching roller and the second stretching roller. The overall stretching ratio was set to 3.3 times, and the take-up speed was changed to 3200m / min. All other things being done, the same method as in Example 1 was used to obtain 33dtex, 5-filament nylon 6 multifilament. The evaluation results are shown in Table 2.

[0149]

[0150]

[0151] [Example 11]

[0152] The output rate was set to 19.20 g / min, a spinneret with 48 orifices, circular shape, φ0.20 orifice diameter, and 6 filaments / nozzle was used, the draw ratio was set to 3.2 times, the take-up speed was set to 3040 m / min, and the take-up tension was changed to 0.2 cN / dtex. All other things being done, the same method as in Example 1 was used to obtain 11 dtex, 8-filament nylon 6 multifilament. The evaluation results are shown in Table 3.

[0153] (Fabric manufacturing)

[0154] The obtained multifilament yarns were warped 1000 times and wound onto a warp beam. The yarns wound on the warp beam were then sized and dried to prepare the warp yarns. Next, the obtained multifilament yarns were woven into the weft yarns through the shed of a water-jet loom to produce a fabric. The woven fabric was then refined, heat-set (intermediate setting) at 180°C, dyed, and calendered at 180°C to obtain the fabric for outdoor jackets. The evaluation results of the obtained fabric are shown in Table 3.

[0155] [Comparative Example 9]

[0156] The winding speed was set to 3160 m / min, and the winding tension was changed to 0.13 g / dtex. Otherwise, the same method as in Example 11 was used to obtain 11 dtex, 8-filament nylon 6 multifilament. The evaluation results are shown in Table 3.

[0157] [Comparative Example 10]

[0158] The temperature of the stretching roller was changed to 180°C, and the same method as in Example 11 was used to obtain 11 dtex, 8-filament nylon 6 multifilament. The evaluation results are shown in Table 3.

[0159] Table 3

[0160]

[0161] Explanation of reference numerals in the attached figures

[0162] 1: Spinning head

[0163] 2: Gas supply device

[0164] 3: Heating cylinder

[0165] 4: Cooling device

[0166] 5: Oil supply device

[0167] 6: Fluid Interchange Nozzle Device

[0168] 7: Traction roller

[0169] 8: Stretching roller

[0170] 9: Winding device

Claims

1. A polyamide multifilament obtained by a single-stage stretching process. Strength above 7.0 cN / dtex Elongation rate is 33-50%. The total fineness is below 56 dtex. Less than 1 unit per 100,000 m of downy hair and loose hair. The dry heat shrinkage rate at 180℃ is less than 12.0%. The polyamide multifilament is manufactured using the following direct spinning and drawing method: polyamide resin is melted, the filaments ejected from the spinning head are cooled and solidified, oiled and interlocked, then stretched, heat-treated, and wound using rollers at different circumferential speeds. The stretching is a single-stage stretching process. in, The following conditions (A) to (D) must be met: (A) The degree of interlacing before stretching is 20~50. (B) Stretch ratio of 3.0~3.5, (C) The heat setting temperature is a temperature above 35°C and below 15°C below the melting point of the polyamide resin. (D) The winding tension between the stretching roller and the winding device is 0.15~0.20cN / dtex.

2. A woven fabric comprising the polyamide multifilament as described in claim 1.

3. A method for manufacturing polyamide multifilament, comprising a direct spinning and stretching method as follows: melting polyamide resin, cooling and solidifying the filaments extruded from the spinning head, performing oiling and interlacing treatments, stretching and heat-treating using rollers at different circumferential speeds, and then winding the filaments, wherein the stretching is a single-stage stretching. The manufacturing method is a method for manufacturing the polyamide multifilament according to claim 1, characterized in that... The following conditions (A) to (D) must be met: (A) The degree of interlacing before stretching is 20~50. (B) Stretch ratio of 3.0~3.5, (C) The heat setting temperature is a temperature above 35°C and below 15°C below the melting point of the polyamide resin. (D) The winding tension between the stretching roller and the winding device is 0.15~0.20cN / dtex.

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