Polyamide crimped yarn, false twist textured yarn and cloth

Abstract

Provided is a polyamide latent crimping composite fiber that suppresses variation in shrinkage and has good quality with less wrinkles / creases caused by uneven dyeing and uneven crimping. The polyamide crimping yarn of the present invention contains a composite polyamide fiber of a side-by-side type or an eccentric core-sheath type, and has a hygrothermal shrinkage stress variation rate of 150% or less.

Description

Technical Field

[0001] This invention relates to a crimped yarn, false-twist yarn, and fabric comprising composite polyamide fibers in a parallel or eccentric core-sheath configuration. Background Technology

[0002] Polyamide fibers have long been widely used in clothing applications due to their softness and pleasant feel compared to polyester fibers. Representative polyamide fibers for clothing, such as nylon 6 or nylon 66, are single fibers containing a single polymer. Since the fibers themselves are essentially non-stretchable, they can be treated with processes like false twisting to impart stretch, thus enabling their use in stretchable woven fabrics. However, it is difficult to obtain woven fabrics with adequate stretch from these single fibers through processes such as false twisting.

[0003] Therefore, there are methods such as: obtaining a stretchable woven fabric by using elastic fibers; or obtaining a stretchable woven fabric by using two polymers with different properties to make a composite fiber with potential shrinkage properties that can be exhibited by heat treatment such as dyeing processes.

[0004] Furthermore, as a polyamide composite fiber with potential shrinkage properties, a composite fiber in which two polyamides with different viscosities are arranged in a side-by-side or eccentric core-sheath configuration has also been proposed (see Patent Document 1, Patent Document 2, and Patent Document 3).

[0005] For example, Patent Document 1 discloses a false-twist composite yarn in which a resin composition comprising poly(m-xylene-hexamethylene) and polyamide 6 is included as one component. Patent Document 2 discloses a polyamide potential shrinkage yarn comprising a nylon 6 / 66 copolymer as a high-viscosity polymer and nylon 6 as a low-viscosity polymer, and formed by laminating two polyamides with different viscosities in a side-by-side configuration. Furthermore, Patent Document 3 discloses a side-by-side or eccentric core-sheath type false-twist composite polyamide fiber comprising nylon 610 or nylon 612, a polyamide with low water absorption.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-80717

[0009] Patent Document 2: Japanese Patent Application Publication No. 2009-57679

[0010] Patent Document 3: Japanese Patent Application Publication No. 2018-3190 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, in the composite fibers described in Patent Documents 1 and 2, which are made by bonding two polymers with different properties, there is a problem as follows: due to slight viscosity variations in each polymer, the stress applied to each polymer during the spinning-drawing process changes, resulting in deviations in fiber orientation / crystallinity along the length direction. This leads to large deviations in the shrinkage rate of the crimped or false-twisted yarn obtained from the composite fibers, resulting in uneven dyeing and uneven crimping. Furthermore, even when the yarn itself has excellent crimp, the characteristic wrinkles of polyamide fibers are easily induced during the humid heat process of refining or dyeing the woven fabric. These wrinkles are difficult to eliminate, therefore, tension must be applied to the woven fabric during the humid heat process. As described above, the polyamide composite fibers described in Patent Documents 1 and 2 have the following problem: because tension is applied to the woven fabric during the humid heat process, the crimp inherent in the original or processed yarn cannot be fully manifested, resulting in a woven fabric lacking stretchability.

[0013] In Patent Document 3, regarding the problem of wrinkling in polyamide composite fibers, it is described that by producing parallel or eccentric core-sheath type polyamide composite fibers containing a nylon 610 or nylon 612 composed of a low-absorbency polyamide, wrinkling is less likely to occur during the manufacturing of woven fabrics in humid and hot processes such as dyeing, and sufficient stretchability can be imparted. However, similar to Patent Documents 1 and 2, the following problems exist: deviations in fiber orientation / crystallinity due to slight viscosity variations, deviations in shrinkage rate of crimped or false-twisted yarns, uneven dyeing, uneven crimping, etc.

[0014] Therefore, the object of the present invention is to solve the aforementioned problems and to provide a polyamide crimped yarn that suppresses deviations in shrinkage rate and has good quality with fewer wrinkles / folds caused by uneven dyeing and uneven crimping.

[0015] Technical means to solve the problem

[0016] To achieve the aforementioned objectives, the polyamide crimped yarn and false twisted yarn of the present invention comprise the following structure.

[0017] (1) A polyamide crimped yarn comprising parallel or eccentric core-sheath type composite polyamide fibers, wherein the wet heat shrinkage stress variation rate is less than 150%.

[0018] (2) The polyamide shrink yarn described in (1) is made by bonding two polyamides with different shrinkage properties in a side-by-side or eccentric core-sheath type.

[0019] (3) The polyamide crimped yarn as described in (1) or (2), wherein the wet heat shrinkage stress is 0.001 cN / dtex to 0.50 cN / dtex.

[0020] (4) The polyamide crimped yarn described in any one of (1) to (3), wherein the stretch elongation is 15% to 100%.

[0021] (5) A false twist yarn comprising the polyamide crimped yarn described in any one of (1) to (4).

[0022] (6) The false twisted yarn described in (5) wherein the wet heat shrinkage stress variation rate is less than 150%.

[0023] (7) The false twisted yarn described in (5) has a stretch elongation of 70% to 300%.

[0024] (8) A fabric comprising false-twisted yarn as described in (7).

[0025] The effects of the invention

[0026] According to the present invention, a stretchable polyamide woven fabric is provided that suppresses the deviation of shrinkage rate, which is a problem of polyamide shrinkage yarn and false twist yarn, and has good quality with fewer wrinkles / folds caused by uneven dyeing and uneven shrinkage. Attached Figure Description

[0027] [ Figure 1 ] Figure 1 This is a diagram used to illustrate the method of using composite fibers. Figure 1 (a) is a cross-sectional view showing the parallel and eccentric core-sheath types of embodiments. Figure 1 (b) is a diagram illustrating the eccentric configuration in eccentric core-sheath type composite fibers.

[0028] [ Figure 2 ] Figure 2 This is a schematic process diagram illustrating one embodiment of a manufacturing apparatus preferably used as a method for manufacturing polyamide crimped yarn according to the present invention. Detailed Implementation

[0029] The present invention will now be described in more detail.

[0030] In this specification, "mass" and "weight" have the same meaning.

[0031] The polyamide crimped yarn of the present invention comprises parallel or eccentric core-sheath type composite polyamide fibers, and the wet heat shrinkage stress variation rate is less than 150%.

[0032] <Two types of polyamides (PA) with different shrinkage properties>

[0033] The parallel or eccentric core-sheath structure of the composite polyamide fiber forming the polyamide crimped yarn of the present invention is preferably formed by two polyamides with different shrinkage characteristics. That is, the composite polyamide fiber is composed of crystalline polyamide (A) and crystalline polyamide (B) as two polyamide components with different shrinkage characteristics. By including polyamide in both components, the affinity of the composite interface is high, which can prevent interface delamination, reduce cross-sectional deviation or poor cross-sectional shape, and allow for uniform oiling and interlacing. Therefore, polyamide crimped yarn with less oil deviation or interlacing deviation can be obtained.

[0034] When exemplifying polyamides, examples include: nylon 6, nylon 66, nylon 4, nylon 11, nylon 12, nylon 410, nylon 510, nylon 610, nylon 612, and copolymers of these as main components.

[0035] Regarding the shrinkage characteristics of crystalline polyamide (A) and crystalline polyamide (B), there are no particular limitations as long as the effect of the present invention is not impaired. The difference in boiling water shrinkage rate when each polymer is used as a single yarn is preferably 5.0% or more. The practical upper limit for the difference in boiling water shrinkage rate is 40%.

[0036] In addition, the boiling water shrinkage rate is calculated by taking a sample of a single yarn skein of a 33dtex 12 filament of the polymer, applying a load of 90mg / dtex for 30 seconds, determining the length B, then immersing it in boiling water at 100°C for 20 minutes, air-drying it, applying a load of 90mg / dtex for 30 seconds, determining the length A, and then calculating it according to the following formula.

[0037] Boiling water shrinkage rate (%) = [(BA) / B] × 100

[0038] <Crystall Polyamide (A)>

[0039] Crystalline polyamide (A) is defined as a type of polyamide different from crystalline polyamide (B) among the illustrated polyamides. As crystalline polyamide (A), preferred are nylon 6, nylon 66, nylon 4, nylon 610, nylon 11, nylon 12, and copolymers thereof as main components.

[0040] Crystalline polyamide (A) may contain components other than lactam, aminocarboxylic acid, diamine and dicarboxylic acid in its repeating structure, provided that such components do not impair the effectiveness of the invention.

[0041] Furthermore, from the viewpoints of yarn-making properties, strength, and anti-peel properties, crystalline polyamide (A) is preferably a polymer in which 90 mol% or more of the repeating structure is a single lactam, aminocarboxylic acid, or a combination of diamines and dicarboxylic acids, and more preferably a polymer in which 95 mol% or more of the repeating structure is a single lactam, aminocarboxylic acid, or a combination of diamines and dicarboxylic acids.

[0042] <Crystall Polyamide (B)>

[0043] The crystalline polyamide (B) can be any polymer as long as its shrinkage characteristics differ from those of the crystalline polyamide (A). Examples of crystalline polyamides (B) include the polyamides described above. The crystalline polyamide (B) is preferably nylon 6, nylon 66, nylon 4, nylon 610, nylon 11, nylon 12, and copolymers thereof as main components. Among these, polymers in which 90 mol% or more of the repeating structure is a single lactam, aminocarboxylic acid, or a combination of diamines and dicarboxylic acids are preferred; more preferably, polymers in which 95 mol% or more of the repeating structure is a single lactam, aminocarboxylic acid, or a combination of diamines and dicarboxylic acids are preferred.

[0044] <Combinations of polyamides>

[0045] The combination of crystalline polyamide (A) and crystalline polyamide (B) in the composite polyamide fiber is preferably a combination of nylon 610 or nylon 612 and nylon 6. By adopting the above structure, fabrics exhibiting excellent shrinkage properties and possessing excellent hand feel, durability, and soft stretchability can be formed.

[0046] <Additives>

[0047] In addition, depending on the needs, pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, plasticizers, release agents, lubricants, foaming agents, antistatic agents, formability modifiers and reinforcing agents can be added to crystalline polyamide (A) and crystalline polyamide (B) for use.

[0048] <Composite>

[0049] The composite polyamide fiber forming the polyamide crimped yarn of the present invention has a composite profile formed by bonding two crystalline polyamides with different shrinkage properties. Preferably, the two crystalline polyamides are substantially inseparable and exist in a bonded state. Examples of composite profiles include, for instance... Figure 1 The parallel type (symbols 10a to 10c) or the eccentric core-sheath type (symbol 10d) shown in (a). In the eccentric core-sheath type composite polyamide fiber 10d, the crystalline polyamide (A) (symbol A) as the core component is covered by the crystalline polyamide (B) (symbol B) as the sheath component. Figure 1In the eccentric core-sheath type composite polyamide fiber 10d shown in (a), a structure is shown in which crystalline polyamide (A) forms the core. Since it is only necessary to contain two components with different shrinkage properties, crystalline polyamide (B) can also be the core. Specifically, the structure can be that the polyamide on the low-shrinkage side is located in the core, and the high-shrinkage polyamide with a higher shrinkage property than the low-shrinkage polyamide becomes the sheath, or the opposite structure can be used.

[0050] The interface between crystalline polyamide (A) and crystalline polyamide (B) in the cross-section of composite polyamide fibers can be flat or smooth. Furthermore, the bonded interface can be straight or curved. By setting the composite polyamide fibers to a side-by-side or eccentric core-sheath configuration, curling occurs based on the shrinkage difference between the two components.

[0051] Furthermore, regarding the composite ratio of crystalline polyamide (A) and crystalline polyamide (B), the area ratio in the cross section of the fiber perpendicular to the long axis of the fiber is preferably crystalline polyamide (A): crystalline polyamide (B) = 2:1 to 1:2.

[0052] In eccentric core-sheath type composite polyamide fibers, such as Figure 1 As shown in (b), the ratio L / M between the distance L between the center 11 of the eccentric core-sheath type composite polyamide fiber 10d and the center 12 of the crystalline polyamide (A) which serves as the core, and the length M of the intersection point of the straight line extending the distance L and the outer periphery of the yarn, is more preferably 1 / 8 to 1 / 2. Furthermore, the so-called center of the core refers to the position of the centroid of the core in the cross-section of the fiber.

[0053] <Wet heat shrinkage stress variation rate / shrunk yarn / false twist yarn>

[0054] The wet heat shrinkage stress variation rate of the polyamide crimped yarn of the present invention is less than 150%.

[0055] By limiting the wet-heat shrinkage stress variation rate to below 150%, deviations in yarn shrinkage under wet-heat conditions, such as during refining or dyeing processes, can be suppressed, reducing uneven dyeing and shrinkage during these processes. As a result, woven fabrics with good quality and excellent tensile strength can be obtained.

[0056] In contrast, if the rate of change of wet heat shrinkage stress exceeds 150%, uneven dyeing and uneven shrinkage are likely to occur during the refining or dyeing process, resulting in poor quality and reduced fabric tensile strength.

[0057] The variation rate of damp heat shrinkage stress is preferably 120% or less. Furthermore, the practical lower limit for the variation rate of damp heat shrinkage stress is 50%.

[0058] Furthermore, the wet heat shrinkage stress variation rate of the false-twist yarn comprising the polyamide crimped yarn of the present invention is preferably 150% or less. More preferably, the wet heat shrinkage stress variation rate is 120% or less, and the practical lower limit of the wet heat shrinkage stress variation rate is 0.5%. If the wet heat shrinkage stress variation rate of the false-twist yarn is within the aforementioned range, deviations in the shrinkage rate of the false-twist yarn under wet heat conditions can be suppressed, thereby reducing uneven dyeing and uneven crimping during processing.

[0059] The aforementioned rate of variation in wet heat shrinkage stress refers to the deviation (coefficient of variation, CV%) of the shrinkage stress generated during heat treatment under wet heat conditions, continuously measured along the fiber axis using the "FTA-500" continuous heat shrinkage measuring instrument manufactured by Toray Engineering. In the "FTA-500," the yarn is moved between a feed roller and a draw roller, wet heat treatment is performed using a heated water bath located between the rollers, and the shrinkage stress is continuously measured using a tension measuring instrument located behind it.

[0060] The wet heat shrinkage stress variation rate is calculated by measuring the shrinkage stress of each yarn strip at a frequency of 6 times per 1cm, taking the average value of the 6 measurements as one data point, and collecting more than 1000 data points. The average value f is then calculated based on the 1000 data points obtained. ave The standard deviation σf is calculated using the following formula.

[0061] Moist heat shrinkage stress variation rate (%) = (standard deviation σf) / (mean f) ave )×100

[0062] The testing conditions were as follows: the yarn to be tested was set to 25m, the speed ratio of the feed roller to the traction roller was set to 99 / 100, the temperature of the heating water tank was set to 100℃, and the yarn speed was set to 5m / minute.

[0063] <Moisture-Heat Shrinkage Stress>

[0064] In addition, the average value f of the shrinkage stress obtained by measurement using the continuous heat shrinkage measuring instrument "FTA-500" will be used. ave The value obtained by dividing the total fineness by the total fineness measured according to Japanese Industrial Standards (JIS) L1013 (2010) is set as the wet heat shrinkage stress.

[0065] The wet heat shrinkage stress of the polyamide crimped yarn of the present invention is preferably 0.001 cN / dtex to 0.50 cN / dtex. By setting it to this range, sufficient loop crimp can be observed even in fabrics where the yarn is bound, thus obtaining a woven fabric with excellent tensile strength.

[0066] The damp heat shrinkage stress is preferably 0.002 cN / dtex to 0.40 cN / dtex.

[0067] <Total fineness, single yarn fineness>

[0068] When considering the application in clothing, the total fineness of the polyamide crimped yarn is preferably 20 dtex to 200 dtex. Furthermore, there is no limitation on the fineness of the individual yarns as long as it does not impair the effectiveness of the invention; however, when used for sportswear, down jackets, linings, and inner linings, 1.0 dtex to 6.0 dtex is preferred.

[0069] <Stretch>

[0070] The elongation of the polyamide crimped yarn is preferably 50% to 80%. By setting it to this range, the actual twist number added during false twisting becomes appropriate, imparting uniform crimp to the obtained processed yarn, thereby obtaining processed yarn with less reduction in crimp during warp changes or repeated stretching.

[0071] <Elongation>

[0072] The stretch elongation of the polyamide crimped yarn of the present invention is preferably 15% or more. By setting it to this range, sufficient loop crimping is achieved, thereby obtaining a fabric with good softness and stretchability.

[0073] The practical upper limit for elongation is 100%. More preferably, the elongation of the polyamide crimped yarn is 16% or more, and even more preferably 17% or more.

[0074] Furthermore, the stretch elongation of the false-twist yarn of the present invention is preferably 70% or more. By setting it to this range, sufficient loop shrinkage is achieved, thereby obtaining a fabric with good softness and stretchability.

[0075] The practical upper limit for elongation is 300%. For false-twist yarns, elongation is more preferably 75% or more, and even more preferably 80% or more.

[0076] The elongation is calculated by taking a 1m circumference loop of yarn, immersing it in boiling water at 90℃ for 20 minutes, air-drying it, applying a load of 1.8mg / dtex for 30 seconds, determining the length A, then applying a load of 90mg / dtex for 30 seconds, determining the length B, and then calculating it according to the following formula.

[0077] Elongation (%) = [(BA) / B] × 100

[0078] <Manufacturing Method>

[0079] The method for manufacturing the polyamide crimped yarn of the present invention will be described.

[0080] In the method for manufacturing polyamide crimped yarn of the present invention, the polyamide on the low-shrinkage side is preferably designed to suppress viscosity increase during melt retention. It is known that polyamide undergoes polymerization reaction due to retention during melt spinning, thereby increasing viscosity. Therefore, by adjusting the chip moisture content of the polyamide on the low-shrinkage side and controlling the polymerization equilibrium reaction, the viscosity increase caused by retention during melt spinning can be suppressed.

[0081] Regarding the polyamide on the low-shrinkage side, when the melt viscosity immediately after melting in melt spinning is defined as η0, and the melt viscosity just before exiting the spinning die is defined as ηs, it is preferable that ηs-η0 ≤ 50 poise. By setting ηs-η0 to 50 poise or less, the viscosity increase of the low-shrinkage polyamide can be suppressed, and the stress during spinning-stretching can be appropriately applied to the high-shrinkage polyamide, resulting in orientation difference, thus obtaining a preferred potential shrinkage. ηs-η0 is further preferably -150 poise ≤ ηs-η0 ≤ 50 poise. By setting ηs-η0 to -150 poise or more, the melt viscosity deviation of the polymer in the spinning piping can be suppressed, the fiber structure of the composite fiber can be stabilized, and the shrinkage deviation of the yarn or false twist yarn under humid and hot conditions such as refining or dyeing processes can be suppressed, reducing uneven dyeing and uneven shrinkage during these processes.

[0082] When using nylon 610 with a relative viscosity of 2.7 (based on sulfuric acid) as a low-shrinkage polyamide, the preferred fragment moisture content is 600 ppm to 1800 ppm. With a polyamide moisture content below 1800 ppm, hydrolysis of the polyamide is suppressed when it remains in the melt section, piping, and spinning die, preventing extreme viscosity reduction and thus stabilizing melt viscosity fluctuations. Furthermore, yarn bending during die ejection is suppressed, enabling stable operation.

[0083] Furthermore, the relative viscosity of sulfuric acid is determined by dissolving 0.25g of polyamide in 25ml of 98% by mass sulfuric acid at a concentration of 1g / 100ml, measuring the flow time (T1) at 25°C using an Ostwald viscometer, and then calculating the relative flow time (T2) of T1 to that of 98% by mass sulfuric acid only, using the ratio T1 / T2.

[0084] Regarding the relative viscosity difference of sulfuric acid between crystalline polyamide (A) and crystalline polyamide (B), there is no limitation as long as it does not impair the effects of the present invention, and a range of 0.5 to 1.0 is preferred. By setting the relative viscosity difference of sulfuric acid to 0.5 or more, it is easy to generate a stress difference applied to each polyamide during yarn making, which can produce an orientation difference, thereby obtaining high potential shrinkage performance. In addition, by setting it to 1.0 or less, yarn bending caused by viscosity difference can be suppressed during yarn making, thereby enabling stable yarn making.

[0085] The melt viscosity difference between crystalline polyamide (A) and crystalline polyamide (B) is preferably less than 1000 poise. If the melt viscosity difference is less than 1000 poise, yarn bending during die ejection can be suppressed, enabling stable yarn production, and is therefore preferred. A melt viscosity difference of 600 to 1000 poise is further preferred. If the melt viscosity difference is greater than 600 poise, stress differences applied to each polyamide are easily generated during spinning, resulting in orientation differences, thereby easily obtaining composite polyamide fibers with excellent potential shrinkage properties.

[0086] Furthermore, the composite polyamide fiber forming the polyamide crimped yarn of the present invention has a composite profile formed by bonding two crystalline polyamides. In the parallel type, when the difference in melt viscosity between the two polyamides is large, the polymer flow resistance is different when ejected from the die, and there is a tendency for yarn bending and poor yarn stability to easily occur due to the difference in flow velocity. Therefore, in the manufacture of composite polyamide fibers using crystalline polyamide (A) and crystalline polyamide (B) with a difference in melt viscosity, from the viewpoint of yarn stability, an eccentric core-sheath type is preferred.

[0087] Secondly, the manufacturing method based on high-speed direct spinning will be explained.

[0088] Crystalline polyamide (A) and crystalline polyamide (B) are melted separately, metered and conveyed using a gear pump, and a composite flow is formed directly using conventional methods to achieve a parallel or eccentric core-sheath type. A spinning die for the parallel or eccentric core-sheath type composite fiber is then used to achieve... Figure 1 The composite polyamide fiber sliver is ejected from the spinning die in the manner illustrated in (a). After ejection, the sliver is cooled to 30°C by blowing cooling air through a sliver cooling device such as a chimney. Then, the cooled sliver is oiled and bundled using an oiling device, interlaced by an interlacing device, and then drawn (spinning speed) at 2000 m / min to 4500 m / min using a traction roller, passing between the traction roller and the extension roller. During this process, the sliver is extended at a ratio of 1.0 to 1.5 times, depending on the ratio of the circumferential speeds of the traction roller and the extension roller. Finally, the sliver is wound into a package at a take-up speed of 3000 m / min or higher.

[0089] The preferred spinning speed is 2000 m / min to 3500 m / min. Setting it above 2000 m / min results in a large yarn draft up to the traction roller, easily creating stress differences applied to each polyamide component, which can lead to orientation differences and thus obtain composite polyamide fibers (polyamide crimped yarn) with excellent potential crimping properties. Setting it below 3500 m / min suppresses yarn bending at the die exit, resulting in stable yarn production.

[0090] The false-twist yarn of the present invention can be obtained by conventional false-twist methods. Preferably, the false-twist process is performed using an extension friction false-twist processing apparatus. An example is given below. For instance, the polyamide crimped yarn of the present invention, supplied to the extension friction false-twist processing apparatus, is fed to the supply roller via a desired yarn guide or fluid treatment device. Then, it is guided to the extension roller via a heated false-twist heater, a cooling plate, and a twisting body for extension friction false-twist, and is wound up as false-twist yarn. As extension friction false-twist, friction false-twist processing can be performed before the supply roller of the extension friction false-twist processing apparatus and after extension is applied using a hot pin or hot plate, or it can be performed while extending between the supply roller and the extension roller.

[0091] The twisting method is not limited to spindle twisting, 3-axis twisting machine twisting, or belt clamping. When strengthening the winding, spindle twisting is preferred. When increasing processing speed and reducing production costs, 3-axis twisting machine twisting or belt clamping as a friction twisting method is preferred.

[0092] The polyamide crimped yarn and false-twist processed yarn of the present invention can be woven and braided using existing methods. The resulting fabrics and braids have excellent elasticity.

[0093] In the case of fabrics, the weave may be plain weave, twill weave, satin weave, or any of the variations and mixtures thereof, depending on the intended use.

[0094] In the case of knitted fabrics, the structure can be any of the following, depending on the intended use: plain knit for circular knitting, double rib knit, half-knit for warp knitting, satin knit, jacquard knit, or variations and mixtures thereof.

[0095] Furthermore, the uses of woven fabrics incorporating the polyamide crimped yarn and false-twist processed yarn of the present invention are not limited, but are preferably used for clothing, and more preferably for sportswear, casual wear, or women's and gentlemen's clothing, such as down jackets, windbreakers, golf apparel, and raincoats. It is particularly suitable for sportswear and down jackets.

[0096] Example

[0097] Secondly, the composite polyamide fiber of the present invention will be specifically illustrated through examples.

[0098] A. Melting point:

[0099] For polyamide fragment samples, thermal analysis was performed using a Q1000 instrument manufactured by TA Instruments, and data processing was conducted using Universal Analysis 2000. The thermal analysis was performed under a nitrogen flow (50 mL / min) at a temperature range of -50°C to 300°C, a heating rate of 10°C / min, and with a fragment sample mass of approximately 5 g (calorific data were standardized to normal mass after measurement). The melting point was determined based on the melting peak.

[0100] B. Relative viscosity:

[0101] A 0.25 g sample of polyamide fragments was dissolved in 25 ml of 98% by mass sulfuric acid at a concentration of 1 g / 100 ml. The flow time (T1) at 25°C was measured using an Oswald viscometer. Subsequently, the flow time (T2) of 98% by mass sulfuric acid alone was measured. The ratio of T1 to T2, i.e., T1 / T2, is defined as the relative viscosity of the sulfuric acid.

[0102] C. Melt viscosity (capillary plotter):

[0103] For polyamide fragment samples, the moisture content was adjusted to the specified values ​​as described in Tables 1-3. A capillary plotter 1B manufactured by Toyo Seiki Co., Ltd. was used to progressively change the strain rate and measure the melt viscosity. The measurement temperature was set to the same as the spinning temperature, and measurements were taken at three points: 5 minutes, 10 minutes, and 20 minutes after the sample was placed in the heating furnace until the start of the measurement (holding time). Furthermore, in the examples or comparative examples, 1216 seconds was recorded when the holding time was set to 5 minutes. -1 The melt viscosity. Additionally, the holding time is 1216s. -1 The value obtained by subtracting the minimum value from the maximum value of the melt viscosity (maximum value - minimum value) is set as the melt viscosity variation range.

[0104] D. Fragment moisture content:

[0105] For polyamide fragment samples, a CA-200 micro moisture meter (manufactured by Mitsubishi Chemical Co., Ltd.) was used, and the Karl Fisher reaction electrostatic titration method was used. An electrolyte mainly composed of iodide ions, sulfur dioxide and alcohol was added to the titration cell. Iodine required for titration was generated internally through electrolysis. The amount of electricity required for electrolytic oxidation was accumulated, and the moisture content was calculated.

[0106] E. Boiling water shrinkage rate of single yarn:

[0107] Using the polymers described in the examples as raw materials, the yarn was melt-blown at 280°C using a spinning die with 12 nozzles. The resulting yarn was cooled, oiled, and interlaced, then drawn using a traction roller at 2570 m / min, and subsequently stretched to 1.7 times its original length. It was then heat-fixed at 155°C, and a 33 dtex 12-filament polyamide single yarn was obtained at a take-up speed of 4000 m / min. A sample of the obtained fiber was taken from the skein, and a load of 90 mg / dtex was applied for 30 seconds to determine the length B. The sample was then immersed in boiling water at 100°C for 20 minutes, air-dried, and a load of 90 mg / dtex was applied for 30 seconds to determine the length A. The boiling water shrinkage rate was calculated using the following formula.

[0108] Boiling water shrinkage rate (%) = [(BA) / B] × 100

[0109] F. Total fineness:

[0110] According to JIS L1013 (2010), for fiber samples, 200 skeins were prepared using a measuring machine with a frame circumference of 1.125 m and a tension of 1 / 30 (g). The skeins were dried at 105°C for 60 minutes and then transferred to a desiccator. They were then cooled at 20°C and 55% RH for 30 minutes. The mass of the skeins was measured, and the mass per 10,000 m was calculated based on the obtained values. The total fineness of the fiber yarn was calculated by setting the standard moisture content to 4.5%. Five measurements were performed, and the average value was taken as the total fineness.

[0111] G. Moisture-heat shrinkage stress, rate of change of moisture-heat shrinkage stress:

[0112] Using a heat shrinkage stress tester (manufactured by Toray Engineering, model "FTA-500"), the fiber yarn to be tested was set to 25m, the speed ratio of the feed roller to the traction roller was set to 99 / 100, and a tension of 1 / 50g of the yarn fineness (decitex) was applied. The test was conducted under humid conditions with a set temperature of 100°C in the heated water bath, a yarn speed of 5m / min, and the obtained shrinkage stress was used to calculate the humid heat shrinkage stress and the humid heat shrinkage variation rate according to the following formula.

[0113] Moisture-heat shrinkage stress (cN / dtex) = (average value f) ave (Total fineness)

[0114] Moist heat shrinkage stress variation rate (%) = (standard deviation σf) / (mean f) ave )×100

[0115] H. Elongation at break:

[0116] Prepare a 1m circumference yarn loop from the fiber sample, immerse it in boiling water at 90℃ for 20 minutes, air dry it, apply a load of 1.8mg / dtex for 30 seconds, and calculate the length A. Then, apply a load of 90mg / dtex for 30 seconds and calculate the length B. Calculate the elongation using the following formula.

[0117] Elongation (%) = [(BA) / B] × 100

[0118] I. Strength and elongation:

[0119] Fiber samples were tested using a Tensilon (registered trademark) UCT-100 exciter manufactured by Orientec under constant elongation conditions as specified in JIS L1013 (Test Methods for Chemical Fiber Filament Yarn, 2010). Elongation was determined from the elongation at the point representing maximum strength in the tensile strength-elongation curve. Strength was calculated by dividing the maximum strength by the fineness. Ten tests were performed, and the average value was taken as both strength and elongation.

[0120] J. Fabric Evaluation:

[0121] (a) Manufacturing of weft yarns

[0122] Using N6 (relative viscosity 2.70, melting point 222℃), the yarn was melt-blown at 275℃ using a spinning die with 12 nozzles. After melt-blowing, the resulting yarn was cooled, oiled, and interlaced. It was then drawn using a traction roller at 2570 m / min, stretched to 1.7 times its original length, and heat-fixed at 155℃ to obtain a 70 dtex 12 filament nylon 6 yarn at a take-up speed of 4000 m / min.

[0123] (b) Fabric manufacturing

[0124] The parallel or eccentric core-sheath type polyamide composite false twist processed yarns obtained in Examples 1-10 and Comparative Examples 1-4 were used as warp yarns (warp density 90 yarns / 2.54cm), and the nylon 6 yarns obtained in (a) were used as weft yarns (weft density 90 yarns / 2.54cm) to weave plain weave fabric (warp / processed yarn).

[0125] The obtained fabric was scouring at 80°C for 20 minutes, then adjusted to pH 4 using Kayanol Yellow N5G 1% owf and acetic acid, dyed at 100°C for 30 minutes, then fixed at 80°C for 20 minutes, and finally heat-treated at 170°C for 30 seconds to improve the hand feel.

[0126] (c) Elongation (stretchability) of the fabric in the warp direction

[0127] The elongation in the warp direction of the fabric was determined according to the JIS L1096 method for constant load fabrics (Method B, 2010). Tensile properties were evaluated in three stages. Furthermore, an evaluation of "A" indicates sufficient tensile properties.

[0128] A: More than 15%

[0129] B: 5% or more, but less than 15%

[0130] C: Less than 5%

[0131] (d) Fabric quality

[0132] The quality of the radial stripes on the fabric is confirmed through visual inspection by experienced inspectors and evaluated according to the following four stages. Furthermore, evaluations of "A" and "B" indicate a usable level.

[0133] A: Good

[0134] B: Slightly good (not a flaw, but stripes are visible)

[0135] C: Slightly defective (Although it has defects such as uneven dyeing or streaks, it can be used by cutting around the defective areas, or it can be used as a finished product in the specified color)

[0136] D: Defective (has defects such as uneven dyeing or streaks, and cannot be used as a product).

[0137] [Example 1]

[0138] Nylon 6 (N6) with a relative viscosity of 2.6, a melting point of 222°C, a boiling water shrinkage rate of 13.0% for single yarn, and a moisture content of 50 ppm was used as crystalline polyamide (A). Nylon 610 (N610) with a relative viscosity of 2.7, a melting point of 225°C, a boiling water shrinkage rate of 7.0% for single yarn, and a moisture content of 1400 ppm was used as crystalline polyamide (B). Crystalline polyamide (A) and crystalline polyamide (B) were melted separately and melt-blown at a composite fiber spinning die (12 holes, round holes) with a composite ratio (mass ratio) of crystalline polyamide (A) to crystalline polyamide (B) of 5:5 (spinning temperature 270°C). Regarding the yarn ejected from the die, the yarn is cooled and solidified using a yarn cooling device, as shown in Table 1. After the water-containing oil agent containing wax is supplied through a two-stage oil supply device, it is interwoven using a fluid interlacing nozzle device. Then, it is pulled at 3700 m / min using a traction roller (room temperature 25℃), and extended at 1.15 times between extension rollers (room temperature 25℃). Finally, the package is wound up at a winding speed of 4000 m / min.

[0139] A polyamide potential crimped composite fiber yarn with 63dtex 12 filament, stretch elongation of 17.4%, and wet heat shrinkage stress variation rate of 100% was obtained.

[0140] Using the obtained polyamide potentially crimped composite fiber yarn, false twisting was performed at a heater temperature of 190°C with an extension ratio of 1.25 and a twist ratio (D / Y) of 1.95 to obtain a false twisted yarn with an elongation of 140%. The obtained false twisted yarn was used as warp yarn to weave plain weave fabrics. The resulting fabric exhibited excellent tensile properties and fabric quality. The results are shown in Table 1.

[0141] [Example 2]

[0142] The moisture content of crystalline polyamide (B) was set to 1100 ppm, and it was melt-blown using a spinning die (12 holes, round holes) for parallel composite fibers. It was then stretched to 1.10 times between stretching rollers (room temperature 25°C). Otherwise, a polyamide potential shrinkage composite fiber yarn with a length of 63 dtex 12 filament, a stretch elongation of 18.1%, and a wet heat shrinkage stress variation rate of 110% was obtained using the same method as in Example 1.

[0143] The obtained polyamide potentially crimped composite fiber yarn was false-twisted using the same method as in Example 1 to obtain a false-twisted yarn with an elongation of 145%. The obtained false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile strength and fabric quality. The results are shown in Table 1.

[0144] [Examples 3 and 4]

[0145] Except for changing the moisture content of the crystalline polyamide (B) as shown in Table 1, the polyamide potential shrink composite fiber yarn was obtained using the same method as in Example 1.

[0146] The obtained polyamide potentially crimped composite fiber yarn was false-twisted using the same method as in Example 1, and the resulting false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile properties. Regarding fabric quality, Example 3 showed good results, and Example 4 showed slightly better results. The results are shown in Table 1.

[0147] [Example 5]

[0148] As shown in Table 2, using an eccentric core-sheath type composite fiber spinning die (12 holes, round holes), melt spraying was performed at a spinning temperature of 290°C. In a two-stage oil supply process, a water-containing oiling agent for false twisting was used as the second-stage oiling agent. The yarn was pulled at 3000 m / min using a traction roller (room temperature 25°C) and stretched at 1.20 times between extension rollers (room temperature 25°C). Then, the package was wound at a winding speed of 3582 m / min. Otherwise, a polyamide potential crimp composite fiber yarn with 66 dtex 12 filament, elongation at break of 19.5%, and wet heat shrinkage stress variation of 100% was obtained using the same method as in Example 1.

[0149] The obtained polyamide potentially crimped composite fiber yarn was subjected to frictional false twisting to obtain a false-twist yarn with an elongation of 165%. This false-twist yarn was used as warp yarn to weave plain weave fabrics. The resulting fabric exhibited excellent tensile properties and fabric quality. The results are shown in Table 2.

[0150] [Examples 6-8]

[0151] Except for changing the moisture content of the crystalline polyamide (B) as shown in Table 2, the polyamide potential shrink composite fiber yarn was obtained using the same method as in Example 5.

[0152] The obtained polyamide potentially crimped composite fiber yarn was subjected to frictional false twisting using the same method as in Example 5, and the resulting false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile properties. Regarding fabric quality, Examples 6 and 7 were good, and Example 8 was slightly good. The results are shown in Table 2.

[0153] [Example 9]

[0154] The traction roller speed was set to 2218 m / min, the extension ratio between the traction roller and the extension roller was set to 1.45 times, and the package was wound at a winding speed of 3200 m / min. Otherwise, the polyamide potential crimped composite fiber yarn was obtained using the same method as in Example 5.

[0155] The obtained polyamide potentially crimped composite fiber yarn was subjected to frictional false twisting using the same method as in Example 5. The resulting false-twisted yarn was used as warp yarn to weave a plain weave fabric. The obtained fabric exhibited excellent tensile strength and fabric quality. The results are shown in Table 2.

[0156] [Example 10]

[0157] Except for replacing the polymers of crystalline polyamide (A) and crystalline polyamide (B), the polyamide potential shrink composite fiber yarn was obtained using the same method as in Example 5.

[0158] The obtained polyamide potentially crimped composite fiber yarn was subjected to frictional false twisting using the same method as in Example 5. The resulting false-twisted yarn was used as warp yarn to weave a plain weave fabric. The obtained fabric exhibited excellent tensile strength and fabric quality. The results are shown in Table 2.

[0159] [Table 1]

[0160] Table 1

[0161]

[0162] [Table 2]

[0163] Table 2

[0164]

[0165] [Comparative Example 1]

[0166] Except for using nylon 610 (N610) with a relative viscosity of 2.7, a melting point of 225°C, and a moisture content of 200 ppm as the crystalline polyamide (B), a polyamide potential crimped composite fiber yarn with a length of 63 dtex 12 filament, a stretch elongation of 15.3%, and a wet heat shrinkage stress variation rate of 210% was obtained using the same method as in Example 1.

[0167] The obtained polyamide potentially crimped composite fiber yarn was false-twisted using the same method as in Example 1 to obtain a false-twisted yarn with an elongation of 130%. The obtained false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile strength, but poor fabric quality. The results are shown in Table 3.

[0168] [Comparative Example 2]

[0169] Except that the moisture content of the crystalline polyamide (B) was set to 2000 ppm, a polyamide potential crimped composite fiber yarn with a 63 dtex 12 filament, a stretch elongation of 17.1%, and a wet heat shrinkage stress variation rate of 180% was obtained using the same method as in Example 1.

[0170] The obtained polyamide potentially crimped composite fiber yarn was false-twisted using the same method as in Example 1 to obtain a false-twisted yarn with an elongation of 140%. The obtained false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile strength, but the fabric quality was slightly poor. The results are shown in Table 3.

[0171] [Comparative Example 3]

[0172] Except for using nylon 610 (N610) with a relative viscosity of 2.7, a melting point of 225°C, and a moisture content of 200 ppm as the crystalline polyamide (B), a polyamide potential crimped composite fiber yarn with a length of 66 dtex 12 filament, a stretch elongation of 16.3%, and a wet heat shrinkage stress variation rate of 200% was obtained using the same method as in Example 5.

[0173] The obtained polyamide potentially crimped composite fiber yarn was subjected to frictional false twisting to obtain a false-twisted yarn with an elongation of 145%. This false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile properties, but poor fabric quality. The results are shown in Table 3.

[0174] [Comparative Example 4]

[0175] Except that the moisture content of the crystalline polyamide (B) was set to 2000 ppm, a polyamide potential crimped composite fiber yarn with a length of 66 dtex 12 filament, an elongation at break of 21.1%, and a wet heat shrinkage stress variation of 170% was obtained using the same method as in Example 5.

[0176] The obtained polyamide potentially crimped composite fiber yarn was subjected to frictional false twisting to obtain a false-twisted yarn with an elongation of 175%. This false-twisted yarn was used as warp yarn to weave a plain weave fabric. The resulting fabric exhibited excellent tensile properties, but the fabric quality was slightly poor. The results are shown in Table 3.

[0177] [Table 3]

[0178] Table 3

[0179]

[0180] As can be seen from Tables 1 to 3, fabrics with excellent tensile properties and excellent fabric quality can be obtained in Examples 1 to 10.

[0181] Although the present invention has been described in detail using specific methods, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the intent and scope of the invention. Furthermore, this application is based on Japanese Patent Application No. 2021-036047, filed on March 8, 2021, the entire contents of which are incorporated herein by reference.

[0182] Explanation of symbols

[0183] A: Crystalline polyamide (A)

[0184] B: Crystalline polyamide (B)

[0185] Y: Yarn strip

[0186] 1: Spinning block

[0187] 2: Spinning die opening

[0188] 3: Cooling device

[0189] 4-1: Oil supply unit (first stage)

[0190] 4-2: Oil supply system (second stage)

[0191] 5: Interlaced Nozzle Device

[0192] 6: Traction roller

[0193] 7: Extension Roller

[0194] 8: Winding device

[0195] 10a~10c: Side-by-side composite polyamide fibers

[0196] 10d: Eccentric core-sheath type composite polyamide fiber

[0197] 11: The center of eccentric core-sheath type composite fiber

[0198] 12: The center of the core

Claims

1. A polyamide crimped yarn comprising parallel or eccentric core-sheath composite polyamide fibers, having a wet heat shrinkage stress of 0.001 cN / dtex to 0.50 cN / dtex, an elongation at break of 15% to 100%, and a wet heat shrinkage stress variation rate of less than 150%. The composite polyamide fiber contains two polyamides with different shrinkage properties, wherein the low-shrinkage polyamide has a moisture content of 600 ppm to 1800 ppm. Wet heat shrinkage stress was measured using a continuous heat shrinkage tester. The measurement conditions were as follows: the yarn to be measured was 25 m long; the speed ratio of the feed roller to the traction roller was set to 99 / 100; the temperature of the heating water bath was set to 100℃; the yarn speed was set to 5 m / min; the measurement frequency for each yarn was set to 6 times per 1 cm; the average value of the 6 measurements was used as one data point; and more than 1000 data points were collected. The average value f was calculated based on these 1000 data points. ave , The rate of change of wet heat shrinkage stress was measured using a continuous heat shrinkage tester. The measurement conditions were as follows: the yarn to be measured was set to 25 m; the speed ratio of the feed roller to the traction roller was set to 99 / 100; the temperature of the heating water bath was set to 100℃; the yarn speed was set to 5 m / min; the measurement frequency for the shrinkage stress of each yarn was set to 6 times per 1 cm; the average value of the 6 measurements was used as one data point; and more than 1000 data points were collected. The average value f was calculated based on these 1000 data points. ave The standard deviation σf is calculated using the following formula. Moist heat shrinkage stress variation rate (%) = (standard deviation σf) / (mean f) ave )×100.

2. The polyamide crimped yarn according to claim 1 is formed by bonding two polyamides with different shrinkage properties in a side-by-side or eccentric core-sheath configuration.

3. A false-twist yarn comprising the polyamide crimped yarn as described in claim 1 or 2.

4. The false-twist yarn according to claim 3, wherein, The rate of change of damp heat shrinkage stress is less than 150%.

5. The false-twist yarn according to claim 3, wherein, The elongation rate is 70% to 300%.

6. A fabric comprising the false-twist yarn as described in claim 5.

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