Composite elastic fiber and preparation method therefor

Abstract

Disclosed are a composite elastic fiber and a preparation method therefor. The composite elastic fiber is a side-by-side hollow bicomponent composite elastic fiber, and comprises component A and component B, wherein the component A is nylon 6; the component B comprises a nylon 6 elastomer; the nylon 6 elastomer is a linear block copolymer composed of a polycaprolactam hard segment and a polyether or polyether amine soft segment; the mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, and the mass fraction of the soft segment therein is 10-75%. The composite fiber of the present invention has a high three-dimensional self-crimping capability; moreover, the composite fiber has the characteristics of soft and elastic hand feel, high elongation and excellent resilience, and can be dyed with various types of dyes, resulting in bright colors and deep dyeability; the nylon 6 and the nylon 6 elastomer have a relatively high moisture regain; by using a hollow structure, the composite elastic fiber has superior loftiness, and significantly better breathability and moisture regain compared to other elastic fibers such as polyester T400, spandex, and textured nylon, and offers a softness that closely resembles cotton.

Description

Composite elastic fiber and preparation method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application No. 202410244004.8 filed on March 4, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of fiber materials, and in particular to composite elastic fibers and a preparation method thereof. Background Art

[0004] Spandex is widely used in hosiery, swimwear, underwear, pajamas, sportswear, fashion outerwear, and more. However, spandex production requires complex equipment and processes, resulting in high raw material and processing costs and high prices. Furthermore, the fiber is difficult to dye and cannot be chlorine-bleached during dyeing and finishing, is prone to melting during high-temperature finishing, exhibits whitening and blistering when stretched, exhibits excessive elasticity, and suffers from poor comfort. Furthermore, spandex can deform and wrinkle after use, affecting its appearance.

[0005] To address these issues with spandex fibers, bicomponent composite elastic fibers, represented by T400 and T800, emerged. T400 is a composite fiber made of polyethylene terephthalate (PET) and polypropylene terephthalate (PTT), while T800 is a composite fiber made of polybutylene terephthalate (PBT) and polypropylene terephthalate (PTT). Both T400 and T800 are elastic, fluffy, and soft, and can be used independently as fabrics. These fibers utilize the difference in viscoelasticity between the two polymers to create a smooth spiral curl structure in their composite fibers. However, polyester parallel spinning can only be processed with disperse dyes, resulting in less vibrant colors, low moisture regain, and poor wearing comfort.

[0006] CN103882538A produces composite elastic fibers with a three-dimensional crimped structure by using similar polymers with different intrinsic viscosities, such as PET. However, the elasticity of the fibers produced by this method depends entirely on the resulting three-dimensional self-curling structure. Furthermore, due to the similar chemical structure and composition of the two polymer components, the thermal shrinkage stress during the processing and molding process is limited, resulting in low curl and low elastic recovery. Furthermore, the high modulus of the selected polymers results in a stiff feel to the fibers and their products.

[0007] Therefore, it is particularly important to develop a composite elastic fiber with good elasticity, high elastic recovery rate and easy dyeing. Summary of the Invention

[0008] The purpose of the present invention is to overcome the problems of insufficient elasticity, low moisture regain, low dyeing brightness and hard feel of composite elastic fibers in the prior art, and to provide a composite elastic fiber and a preparation method thereof. The composite elastic fiber has the characteristics of good elasticity, high elastic recovery rate and easy dyeing.

[0009] To achieve the above objectives, the first aspect of the present invention provides a composite elastic fiber, which is a parallel hollow bicomponent composite elastic fiber, comprising component A and component B; wherein component A is nylon 6, and component B contains a nylon 6 elastomer, and the nylon 6 elastomer is a linear block copolymer composed of a polycaprolactam hard segment and a polyether or polyetheramine soft segment, wherein the mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, and the mass fraction of the soft segment is 10-75%.

[0010] A second aspect of the present invention provides a method for preparing a composite elastic fiber, the method comprising:

[0011] (1) reacting caprolactam, polyether or polyetheramine, a capping agent, a catalyst, and a stabilizer in water to obtain a nylon 6 elastomer;

[0012] (2) Nylon 6 is used as component A; the nylon 6 elastomer obtained in step (1) is used as component B; and a parallel hollow bicomponent composite elastic fiber is obtained through melt extrusion, dual-channel parallel composite spinning, composite hollow spinning, cooling, stretching, heat setting and winding.

[0013] The third aspect of the present invention provides a composite elastic fiber produced by the preparation method described in the second aspect.

[0014] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0015] (1) The nylon 6 elastomer used in the present invention has the characteristics of low temperature, softness, high deformation rebound, low modulus, and a large number of dye groups. It can increase the compatibility with nylon 6 in the molten high elastic state and maintain good interface adhesion between the two components. At the same time, the crystallization or thermal shrinkage rate of the nylon 6 elastomer and nylon 6 is different, and a large shrinkage difference is produced after the composite fiber, and it has a high three-dimensional self-curling ability. The composite fiber has the characteristics of soft and elastic feel, high elongation and good recovery, and can be dyed with a variety of dyes to produce bright colors and deep colors.

[0016] (2) The nylon 6 and nylon 6 elastomer in the composite fiber of the present invention have a high moisture regain. The composite elastic fiber with a hollow structure has a better fluffiness, and its air permeability and moisture regain are far superior to other elastic fibers such as polyester T400, spandex, and nylon stretch, and it has a soft feel close to cotton. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a cross-sectional view of a hollow composite fiber of nylon 6 and nylon 6 elastomer provided in parallel according to one embodiment of the present invention;

[0018] FIG2 is a device for preparing hollow composite fibers of nylon 6 and nylon 6 elastomer in parallel, provided by one embodiment of the present invention;

[0019] FIG3 is a comparison of the dyeing of acid dyes on alternating woven socks of nylon 6 fibers and hollow composite fibers of nylon 6 and nylon 6 elastomer provided in parallel, provided by one embodiment of the present invention; wherein, the light-colored area is nylon 6 fibers, and the dark-colored fibers are hollow composite fibers of nylon 6 and nylon 6 elastomer provided in parallel.

[0020] Explanation of Reference Numerals 1a, 1b - Hoppers 2a, 2b - Metering Pumps 3 - Spinning Assembly 4 - Tow 5 - Cooling Jacket 5 - Side Blower 7 - First-Stage Hot Drafting Roller 8 - Second-Stage Hot Drafting Roller 9 - Third-Stage Hot Drafting Roller 10 - Winding Bobbin DETAILED DESCRIPTION

[0021] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0022] In a first aspect, the present invention provides a composite elastic fiber, comprising a parallel hollow bicomponent composite elastic fiber comprising component A and component B. Component A is nylon 6, and component B comprises a nylon 6 elastomer, which is a linear block copolymer composed of a polycaprolactam hard segment and a polyether or polyetheramine soft segment. The mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, and the mass fraction of the soft segment is 10-75%. As shown in Figure 1, the light-colored portion is component A, and the dark-colored portion is component B.

[0023] According to the present invention, the mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, for example, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and any value in a range consisting of any two values, preferably 30-70%. The mass fraction of the soft segment is 10-75%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 65%, 70%, 75%, and any value in a range consisting of any two values, preferably 30-70%.

[0024] According to the present invention, the mass fraction of the hard segment and the mass fraction of the soft segment in the nylon 6 elastomer are determined by using a nuclear magnetic resonance spectrometer with deuterated trifluoroacetic acid (CF3COOD) as a solvent and tetramethylsilane (TMS) as an internal standard to determine the hard and soft segment ratio and the polymer structure.

[0025] According to the present invention, the mass fraction of the hard segment and the mass fraction of the soft segment in the nylon 6 elastomer are determined using a high-resolution nuclear magnetic resonance spectrometer with an 800 MHz magnetic field, a 2-second scan time, 128 cumulative scans, 32K sampling points, a spectral width of 20 ppm, an injection volume of 5 μL, and a temperature of 25°C. An NMR experiment is performed using deuterated trifluoroacetic acid (CF3COOD) as a solvent and tetramethylsilane (TMS) as an internal standard, and the NMR spectrum of the sample is recorded. Peaks in the NMR spectrum are analyzed to identify characteristic peaks of the hard and soft segments. The integrated area of ​​each characteristic peak is determined, and the mass fractions of the hard and soft segments are calculated.

[0026] The nylon 6 elastomer used in the present invention has the characteristics of low temperature, softness, high deformation resilience, low modulus, and a large number of dye azole groups. It can increase the compatibility with the mass fraction of the hard segment and the mass fraction of the soft segment of nylon 6 in a molten high-elastic state, maintaining good interface adhesion between the two components. At the same time, the nylon 6 elastomer and nylon 6 have different crystallization or thermal shrinkage rates, resulting in a large shrinkage difference after composite fiber, and has a high three-dimensional self-curling ability. The composite fiber has a soft and elastic feel, high elongation and good recovery, and can be dyed with a variety of dyes to produce bright colors and deep colors.

[0027] The composite elastic fiber of the present invention can be dyed with either disperse dyes or acid dyes. According to some embodiments of the present invention, component B further comprises nylon 6; based on the total weight of component B, the content of nylon 6 in component B is 0-30 wt%, for example, 0 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, or any value within a range consisting of any two of these values, preferably 0-15 wt%.

[0028] According to the present invention, component B can be a nylon 6 elastomer or a mixture of a nylon 6 elastomer and nylon 6. High-viscosity elastomers have poor flow and spinnability, which is not conducive to parallel compounding. Adding some nylon 6 can adjust the spinnability of the nylon elastomer component B and the shrinkage differences of different types of polymers. If the content of nylon 6 in component B exceeds 30wt%, the performance differences of high rebound and high curl in component B are small and not easy to fully demonstrate.

[0029] By adjusting the mass ratio of nylon 6 and nylon 6 elastomer in component B, the difference in thermal shrinkage can be controlled to achieve the purpose of regulating the change in curl rate and elastic recovery rate.

[0030] According to some embodiments of the present invention, the mass ratio of component A to component B is 1:3-3:1, for example, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 3:1, and any value in the range consisting of any two values.

[0031] According to some embodiments of the present invention, the polyether or polyetheramine in the polyether or polyetheramine soft segment is selected from one or more of polytetrahydrofuran, polypropylene glycol, polyethylene glycol, amino-terminated polyoxypropylene ether and amino-terminated polyoxyethylene ether.

[0032] According to some embodiments of the present invention, the number average molecular weight of the polyether or polyetheramine in the polyether or polyetheramine soft segment is 1000-3000 g / mol, for example, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2500 g / mol, 2800 g / mol, 3000 g / mol, and any value in a range consisting of any two values.

[0033] According to some embodiments of the present invention, the relative viscosity of nylon 6 is 2.4-2.7.

[0034] According to some embodiments of the present invention, the relative viscosity of the nylon 6 elastomer is 2.1-2.6.

[0035] According to some embodiments of the present invention, the hardness of the nylon 6 elastomer is 25-75D.

[0036] According to some embodiments of the present invention, the melting point of the nylon 6 elastomer is 170-215°C.

[0037] The nylon 6 and nylon 6 elastomer in the composite fiber of the present invention have a high moisture regain. The composite elastic fiber with a hollow structure has a better fluffiness, and its air permeability and moisture regain are far superior to other elastic fibers such as polyester T400, spandex, and nylon stretch, and it has a soft feel close to cotton.

[0038] A second aspect of the present invention provides a method for preparing a composite elastic fiber, the method comprising:

[0039] (1) reacting caprolactam, polyether or polyetheramine, a capping agent, a catalyst, and a stabilizer in water to obtain a nylon 6 elastomer;

[0040] (2) Nylon 6 is used as component A; the nylon 6 elastomer obtained in step (1) is used as component B; and a parallel hollow bicomponent composite elastic fiber is obtained through melt extrusion, dual-channel parallel composite spinning, composite hollow spinning, cooling, stretching, heat setting and winding.

[0041] According to the present invention, the nylon 6 elastomer is a linear block copolymer composed of a polycaprolactam hard segment and a polyether or polyetheramine soft segment. The mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, for example, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and any value in a range consisting of any two values, preferably 30-70%; the mass fraction of the soft segment is 10-75%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 65%, 70%, 75%, and any value in a range consisting of any two values, preferably 30-70%.

[0042] According to some embodiments of the present invention, the reaction comprises: first heating to 150-200° C. for reaction for 2-5 hours, then reacting at 180-240° C. for 4-7 hours, and then vacuum polycondensing at 220-265° C. and (-0.09) MPa.

[0043] According to some embodiments of the present invention, the processing temperature of component A is 265-285°C, preferably 270-280°C.

[0044] According to some embodiments of the present invention, the processing temperature of component B is 260-295°C, preferably 265-285°C.

[0045] According to some embodiments of the present invention, the polyether or polyetheramine is selected from one or more of polytetrahydrofuran, polypropylene glycol, polyethylene glycol, amino-terminated polyoxypropylene ether and amino-terminated polyoxyethylene ether.

[0046] According to some embodiments of the present invention, the number average molecular weight of the polyether or polyetheramine is 1000-3000 g / mol, for example, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2500 g / mol, 2800 g / mol, 3000 g / mol, and any value in a range consisting of any two values.

[0047] According to some embodiments of the present invention, the component B further contains nylon 6; based on the total weight of the component B, the content of nylon 6 in the component B is 0-30wt%, for example, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, and any value in a range consisting of any two values, preferably 0-15wt%.

[0048] According to some embodiments of the present invention, the end-capping agent is selected from one or more of adipic acid, sebacic acid, terephthalic acid, cyclohexanedicarboxylic acid and benzoic acid.

[0049] According to some embodiments of the present invention, the catalyst is selected from one or more of phosphoric acid, antimony glycol, antimony trioxide and tetrabutyl titanate.

[0050] According to some embodiments of the present invention, the stretching ratio is 1.2-3, and the stretching temperature is 60°C-110°C.

[0051] According to the present invention, the composite hollow spinneret adopts a hollow spinneret, preferably a combination of hollow, K-shaped, C-shaped and cross-shaped, to increase the elasticity and fluffiness of the composite fiber and make the fiber have better three-dimensional natural curl.

[0052] According to the present invention, the parallel hollow bicomponent composite fibers are filaments or staple fibers and can be used for woven fabrics, knitted fabrics, and blended or interwoven with other fibers, cotton, and wool.

[0053] According to a particularly preferred embodiment of the present invention, a method for preparing a nylon 6 and nylon 6 elastomer parallel hollow composite fiber, using the apparatus shown in FIG2 , specifically comprises the following steps:

[0054] (1) adding caprolactam, polyether, polyetheramine, end-capping agent, catalyst, stabilizer and water into a reaction kettle, heating to 150-200°C for reaction for 2-5 hours, then reacting at 180-240°C for 4-7 hours, then vacuum polycondensing at 220-265°C and -0.09 MPa, and finally extracting and drying to obtain the desired spinning nylon 6 elastomer; wherein the hard segment component of the nylon 6 elastomer is caprolactam, the soft segment component is polyether or polyetheramine, the mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, the mass fraction of the soft segment is 10-75%, the hardness is 25-75D, the melting point is 170-215°C, and the relative viscosity is 2.1-2.6;

[0055] (2) Commercially available high-speed spinning fiber-grade nylon 6 chips (relative viscosity 2.4-2.7) are selected and dried as component A. The nylon 6 elastomer chips prepared in step (1) are then added with 0-80 wt% of high-speed spinning fiber-grade nylon 6 chips and dried as component B. Component A and component B are respectively fed into the melt pipe of the screw extruder through hoppers 1a and 1b, and then enter the double-channel parallel spinning assembly 3 through metering pumps 2a and 2b. The filament bundle 4 is spun out from the composite spinneret, cooled by a slow cooling sleeve 5 and a blower 6 to cool the oil tanker and apply oil, and then respectively subjected to the first, second, and third stage hot drawing. Rollers 7, 8, and 9 are used for stretching and heat setting, and finally the fiber is wound on a winding drum 10 to form a composite hollow elastic fiber. Among them, the processing temperature of component A is 265-285°C, and the processing temperature of component B is 260-295°C. The hollow spinneret is preferably a combination of hollow, K-shaped, C-shaped, and cross-shaped to increase the elasticity and fluffiness of the composite fiber and give the fiber a better three-dimensional natural curvature. A heating medium is used, the draft ratio is 1.2-3, and the stretching temperature is 60°C-110°C. The nylon segment and the hard segment are not easy to form crystals during the drafting stage, and the molecular chain is in a highly oriented state.

[0056] The third aspect of the present invention provides a composite elastic fiber produced by the preparation method described in the second aspect.

[0057] The composite elastic fiber of the present invention is primarily used as a nylon-free four-way stretch fabric and for making nylon elastic clothing. Because the composite elastic fiber of the present invention is a nylon elastic fiber, it has a high moisture regain and is breathable and comfortable. Furthermore, the composite elastic fiber of the present invention is also a parallel hollow elastic fiber, exhibiting excellent resilience and bulkiness. Therefore, it is suitable for making close-fitting elastic clothing such as yoga wear, tights, and underwear.

[0058] In the following preparations, examples, and comparative examples, if no specific conditions are specified, conventional conditions or those recommended by the manufacturer were followed. Reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0059] In the following examples and comparative examples,

[0060] Relative viscosity and intrinsic viscosity: Measured using the Ubbelohde viscometer concentrated sulfuric acid method in accordance with the national standard "GB / T38138-2019 Test Method for Fiber-Grade Polycaprolactam (PA6) Slices." The test temperature is 25 ± 0.01°C, the mass fraction of concentrated sulfuric acid is 96.0 ± 0.1 wt.%, and the sample concentration is 0.010 g / ml.

[0061] Breaking strength: According to the national standard "GB / T14337-2022 Test method for tensile properties of chemical staple fibers", the fiber samples were tensile tested on the fiber samples before and after treatment using an electronic single fiber strength tester. The tensile spacing was set to 20 mm, the tensile speed was 20 mm / min, and the tension clamp was selected to be 0.2 cN for mechanical property testing.

[0062] The curl elasticity is measured using the test method for curl properties of chemical staple fibers specified in GB / T 14338-2022. Fiber pre-conditioning conditions: Fibers are placed at a temperature not exceeding 50°C and a relative humidity of 10% to 25%, and weighed every 30 minutes until a constant weight is achieved. Alternatively, the conditioning time corresponding to the specified moisture regain can be used. The specified moisture regain is specified in GB / T 9994. The fiber bundle is clamped at a distance of 20 mm and subjected to a light tension of L0 and a heavy tension of L1. The curl elasticity is then calculated.

[0063] Moisture regain: Moisture regain is tested according to GB / T 6503-2017, "Test Method for Moisture Gain of Chemical Fibers." After drying, place the fiber sample in a constant temperature and humidity chamber at 20°C and 65% humidity for 8 hours. The balance weight is measured as the pre-drying weight. After the moisture is conditioned, place the sample in the drying basket of the oven, raise the temperature to the specified temperature, and begin recording the drying time. After drying for the specified time, weigh the sample again, repeating the drying cycle every 10 minutes until a constant weight is reached. Calculate the fiber moisture regain.

[0064] Bright nylon 6 chips with a viscosity of 2.4-2.45 were purchased from Haiyang Technology Co., Ltd. "Qiuxue" brand. In the following examples and comparative examples, the viscosity is expressed as 2.45.

[0065] Antioxidants: including antioxidant 1098 and antioxidant 168, with the mass ratio of the two being 1:1.

[0066] Heat stabilizer: Chiguard N-442 (SEED) nylon multifunctional light and heat stabilizer.

[0067] Example 1

[0068] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0069] (1) 41.21 kg of caprolactam, 7.5 kg of polytetrahydrofuran 1000, 1.29 kg of 1,4-cyclohexanedicarboxylic acid, 250 g of tetrabutyl titanate, 50 g of antioxidant, 50 g of thermal stabilizer and 100 g of water were added to a reactor, heated to 190°C for reaction for 3 hours, then reacted at 250°C for 4 hours, and then vacuum polycondensed at 260°C and -0.09 MPa for 2 hours. After extraction and drying, the desired spinning nylon 6 elastomer was obtained with a hardness of 74D and a melting point of 212°C.

[0070] (2) Selecting glossy nylon 6 slices, drying them, and making them into component A; selecting 74D nylon 6 elastomer slices prepared in step (1) as component B; melt-extruded them respectively by screw extruder in a mass ratio of 1:1, and entering a double-channel parallel composite spinning assembly, wherein the temperature of component A is 280°C, and the temperature of component B is 285°C, and passing through a hollow double C-type spinneret, a blower, and a tunnel cooling, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a nylon 6 and nylon 6 elastomer composite hollow elastic fiber.

[0071] Example 2

[0072] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0073] (1) 33.36 kg of caprolactam, 7.5 kg of polypropylene glycol 2000, 7.5 kg of polyethylene glycol 1000, 1.64 kg of adipic acid, 500 g of zirconium n-butoxide, 100 g of antioxidant, 100 g of heat stabilizer and 90 g of water were added to a reactor, heated to 160° C. for reaction for 3 hours, then reacted at 210° C. for 5 hours, and then vacuum polycondensed at 230° C. and -0.09 MPa for 4 hours. After extraction and drying, the desired spun nylon 6 elastomer chips were obtained, with a hardness of 62D and a melting point of 202° C.;

[0074] (2) Selecting glossy nylon 6 slices, drying them, and making them into component A; selecting 62D nylon 6 elastomer slices prepared in step (1) as component B; melt-extruded them respectively by screw extruder in a mass ratio of 1:1, and entering a double-channel parallel composite spinning assembly, wherein the temperature of component A is 270°C, and the temperature of component B is 275°C, and passing through a hollow double C-type spinneret, a blower, and a tunnel cooling, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a nylon 6 and nylon 6 elastomer composite hollow elastic fiber.

[0075] Example 3

[0076] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0077] (1) 17 kg of caprolactam, 30 kg of polytetrahydrofuran 1500, 2.92 kg of adipic acid, 300 g of ethylene glycol antimony, 100 g of antioxidant, 100 g of heat stabilizer and 70 g of water were added to a reactor, heated to 170° C. for reaction for 3 hours, then reacted at 230° C. for 6 hours, and then vacuum polycondensed at 250° C. and -0.09 MPa for 5 hours. After extraction and drying, the desired spun nylon 6 elastomer chips were obtained, with a hardness of 42D and a melting point of 188° C.

[0078] (2) Selecting glossy nylon 6 slices, drying them, and making them into component A; selecting 42D nylon 6 elastomer slices prepared in step (1) as component B; melt-extruded them respectively by screw extruder in a mass ratio of 1:1, and entering a double-channel parallel composite spinning assembly, wherein the temperature of component A is 280°C, and the temperature of component B is 285°C, and passing through a hollow double C-type spinneret, a blower, and a tunnel cooling, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a nylon 6 and nylon 6 elastomer composite hollow elastic fiber.

[0079] Example 4

[0080] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0081] (1) 9.65 kg of caprolactam, 20 kg of amino-terminated polyoxyethylene ether 900, 15 kg of polytetrahydrofuran 1500, 5.35 kg of terephthalic acid, 300 g of ethylene glycol antimony, 150 g of antioxidant, 140 g of heat stabilizer and 70 g of water were added to a reactor, heated to 150° C. for reaction for 4 hours, then reacted at 180° C. for 6 hours, and then vacuum polycondensed at 220° C. and -0.09 MPa for 6 hours. After extraction and drying, the desired spun nylon 6 elastomer chips were obtained, with a hardness of 30D and a melting point of 175° C.;

[0082] (2) Selecting glossy nylon 6 slices, drying them, and making them into component A; selecting 30D nylon 6 elastomer slices prepared in step (1) as component B; melt-extruded them respectively by screw extruder in a mass ratio of 1:1, and entering a double-channel parallel composite spinning assembly, wherein the temperature of component A is 270°C, and the temperature of component B is 250°C, and passing through a hollow double C-type spinneret, a blower, and a tunnel cooling, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a hollow elastic fiber composited with nylon 6 and nylon 6 elastomer.

[0083] Example 5

[0084] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0085] (1) 33.54 kg of caprolactam, 10 kg of polypropylene glycol 2000, 5 kg of polyethylene glycol 1000, 1.46 kg of adipic acid, 500 g of zirconium n-butoxide, 100 g of antioxidant, 100 g of heat stabilizer and 90 g of water were added to a reactor, heated to 170°C for reaction for 3 hours, then reacted at 240°C for 5 hours, and then vacuum polycondensed at 250°C and -0.09 MPa for 4 hours. After extraction and drying, the desired spun nylon 6 elastomer chips were obtained, with a hardness of 62D and a melting point of 202°C.

[0086] (2) Selecting bright nylon 6 slices, drying them, and making component A; selecting 62D nylon 6 elastomer slices prepared in step (1) and adding 20% ​​bright nylon 6 slices as component B; melt-extruded them respectively by screw extruder in a mass ratio of 1:1, entering a double-channel parallel composite spinning assembly, the temperature of component A is 280°C, the temperature of component B is 290°C, passing through a hollow double C-type spinneret, blow-by-wind, and cooling in a tunnel, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a hollow elastic fiber composited with nylon 6 and nylon 6 elastomer.

[0087] Example 6

[0088] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0089] (1) 9.83 kg of caprolactam, 17.5 kg of amino-terminated polyoxyethylene ether 900, 17.5 kg of polytetrahydrofuran 1500, 5.17 kg of terephthalic acid, 300 g of ethylene glycol antimony, 150 g of antioxidant, 140 g of heat stabilizer and 70 g of water were added into a reactor, with the mass content of the hard segment being 30% and the mass content of the composite soft segment being 70%. The mixture was heated to 160° C. for reaction for 4 hours, then reacted at 200° C. for 6 hours, and then vacuum polycondensed at 230° C. and -0.09 MPa for 6 hours. After extraction and drying, the desired spinning nylon 6 elastomer chips were obtained, with a hardness of 30D and a melting point of 175° C.

[0090] (2) Selecting glossy nylon 6 slices, drying them, and making component A; selecting 30D nylon 6 elastomer slices prepared in step (1) and adding 80% glossy nylon 6 slices as component B; melt-extruded by a screw extruder in a mass ratio of 1:1, entering a double-channel parallel composite spinning assembly, the temperature of component A is 275°C, the temperature of component B is 270°C, passing through a hollow double C-type spinneret, blow-by air, and cooling in a tunnel, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a nylon 6 and nylon 6 elastomer composite hollow elastic fiber.

[0091] Example 7

[0092] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0093] (1) 18 kg of caprolactam, 30 kg of polytetrahydrofuran 2500, 1.99 kg of terephthalic acid, 300 g of ethylene glycol antimony, 100 g of antioxidant, 100 g of heat stabilizer and 70 g of water were added to a reactor, heated to 170° C. for reaction for 3 hours, then reacted at 230° C. for 6 hours, and then vacuum polycondensed at 250° C. and -0.09 MPa for 5 hours. After extraction and drying, the desired spinning nylon 6 elastomer chips were obtained, with a hardness of 42D and a melting point of 188° C.

[0094] (2) Selecting glossy nylon 6 slices and drying them as component A, and selecting 42D nylon 6 elastomer slices prepared in step (1) as component B; melt-extruded them by screw extruder in a mass ratio of 3:1, and entering a double-channel parallel composite spinning assembly, the temperature of component A is 280°C, and the temperature of component B is 285°C, and passing through a hollow double C-type spinneret, a blower, and a tunnel cooling, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a nylon 6 and nylon 6 elastomer composite hollow elastic fiber.

[0095] Example 8

[0096] A nylon 6 and nylon 6 elastomer parallel hollow composite elastomer fiber, the preparation method of which comprises the following steps:

[0097] (1) 17.42 kg of caprolactam, 30 kg of polytetrahydrofuran 2000, 2.58 kg of 1,4-cyclohexanedicarboxylic acid, 300 g of ethylene glycol antimony, 100 g of antioxidant, 100 g of heat stabilizer and 70 g of water were added to a reactor, heated to 160° C. for reaction for 3 hours, then reacted at 190° C. for 6 hours, and then vacuum polycondensed at 210° C. and -0.09 MPa for 5 hours. After extraction and drying, the desired spun nylon 6 elastomer chips were obtained, with a hardness of 42D and a melting point of 188° C.;

[0098] (2) Selecting glossy nylon 6 slices (relative viscosity 2.45) and drying them as component A, and selecting 42D nylon 6 elastomer slices prepared in step (1) as component B; melt-extruded by a screw extruder in a mass ratio of 1:3, and entering a double-channel parallel composite spinning assembly, the temperature of component A is 270°C, and the temperature of component B is 265°C, and passing through a hollow double C-type spinneret, a blower, and a tunnel cooling, and then passing through the first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally winding to obtain a nylon 6 and nylon 6 elastomer composite hollow elastic fiber.

[0099] Comparative Example 1

[0100] The PET and PTT parallel composite elastomer fibers are prepared by the following method: PET chips (intrinsic viscosity 0.65) commercially available from Hengli Petrochemical Co., Ltd. are used and dried to prepare component A; PTT chips (intrinsic viscosity 0.6) commercially available from Shenghong Group Co., Ltd. are used and dried to prepare component B; they are melt-extruded by a screw extruder in a mass ratio of 1:1, and enter a dual-channel parallel composite spinning assembly, with the temperature of component A being 290°C and the temperature of component B being 295°C. The fibers are cooled through a common spinneret, a blower, and a tunnel, and then stretched and qualitatively oiled through the first, second, and third hot drawing rollers, respectively. Finally, the fibers are wound to obtain the PET / PTT elastic fibers.

[0101] Comparative Example 2

[0102] PA6 and TPEE parallel composite elastomer fibers are prepared by the following method: glossy nylon 6 chips are used and dried to prepare component A; commercially available TPEE chips from DuPont are used and dried to prepare component B; the fibers are melt-extruded by a screw extruder in a mass ratio of 1:1, and then enter a dual-channel parallel composite spinning assembly, with component A and component B having a temperature of 280°C and 285°C, and then pass through a common spinneret, a blower, and a cooling channel, and then pass through first, second, and third hot drawing rollers for stretching and qualitative oiling, and finally are wound to obtain PET / PTT elastic fibers.

[0103] Comparative Example 3

[0104] PA6 and PA66 parallel composite fibers are prepared by the following method: glossy nylon 6 chips are used and dried to prepare component A; PA66 chips (relative viscosity 2.55) commercially available from China Shenma Group Co., Ltd. are used and dried to prepare component B; the components are melt-extruded by a screw extruder in a mass ratio of 1:1, and enter a dual-channel parallel composite spinning assembly, with the temperature of component A being 270°C and the temperature of component B being 295°C. The components are passed through a common spinneret, blown by air, and cooled in a tunnel, and then respectively stretched and qualitatively oiled by first, second, and third hot drawing rollers, and finally wound to obtain the PA6 / PA66 composite fiber.

[0105] Performance Testing

[0106] The performance of the parallel composite elastic fibers prepared in the above embodiments and comparative examples was tested, and the results are shown in Table 1.

[0107] Table 1

[0108] The dyeing in Table 1 was performed using acid dyes, and the color uniformity and depth after dyeing were compared. Using the same acid dye and the same dyeing process conditions, the dyeing time was 105 minutes, with the chroma of conventional nylon 6 fiber as the benchmark chroma, and the benchmark chroma was defined as dyeable; dyeing that was darker than the benchmark chroma after 105 minutes was defined as easy to dye; dyeing that was lighter or whiter than the benchmark chroma after 105 minutes, and still very light or almost invisible even after 120 minutes, was defined as difficult to dye. Figure 3 shows a comparison of acid dye dyeing of nylon 6 fiber and a hollow composite fiber of nylon 6 and nylon 6 elastomer alternately woven socks; the light-colored area is nylon 6 fiber, and the dark-colored area is the composite elastic fiber of the present invention.

[0109] Under the same acid dye and the same dyeing process conditions, the dye uptake rate of conventional nylon fiber is 60-70%, while the dye uptake rate of the composite elastic fiber of the present invention is 85-95%.

[0110] Under the same acid dye and dyeing conditions, the dyeing curve of conventional nylon 6 fiber is generally 110-120 minutes, while the dyeing curve of the composite elastic fiber of the present invention is approximately 95-105 minutes. In other words, under the same dyeing conditions, to achieve the same chromaticity, the composite elastic fiber of the present invention is approximately 20-30% faster than conventional nylon fiber.

[0111] As can be seen from the table, the nylon 6 and nylon 6 hollow composite elastic fibers obtained in Examples 1-8 of the present invention have good elastic crimp, moisture regain, and dyeing properties, especially Examples 2-5 have better elastic crimp, moisture regain, and dyeing properties. Comparative Example 1 uses ordinary PET and PTT to make parallel composite fibers, which are solid fibers. The moisture regain is on the low side, not enough to absorb moisture and be comfortable to wear, the dyeing is limited, and the crimp is low. Comparative Example 2 uses nylon 6 and polyester elastomer to make parallel composite fibers. The compatibility is not good enough, which affects the bonding strength of the composite spinning and the composite is unsuccessful. Comparative Example 3 uses nylon 6 and nylon 66 to make parallel composite fibers. It is a solid fiber, dyes evenly and dyes well, and the bending elastic modulus and moisture regain are both on the low side. It can be seen that the present invention is a comprehensive optimization of the structure, viscosity, performance, and parallel composite spinning formula and processing technology of nylon 6 elastomer.

[0112] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A composite elastic fiber, characterized in that: The composite elastic fiber is a parallel hollow bicomponent composite elastic fiber, comprising component A and component B; wherein component A is nylon 6, and component B contains a nylon 6 elastomer, and the nylon 6 elastomer is a linear block copolymer composed of a polycaprolactam hard segment and a polyether or polyetheramine soft segment, wherein the mass fraction of the hard segment in the nylon 6 elastomer is 25-90%, and the mass fraction of the soft segment is 10-75%.

2. The composite elastic fiber according to claim 1, wherein The component B further contains nylon 6; based on the total weight of the component B, the content of nylon 6 in the component B is 0-30 wt%.

3. The composite elastic fiber according to claim 1 or 2, wherein The polyether or polyetheramine in the polyether or polyetheramine soft segment is selected from one or more of polytetrahydrofuran, polypropylene glycol, polyethylene glycol, amino-terminated polyoxypropylene ether and amino-terminated polyoxyethylene ether.

4. The composite elastic fiber according to claim 2 or 3, wherein The number average molecular weight of the polyether or polyetheramine in the polyether or polyetheramine soft segment is 1500-3000 g / mol.

5. The composite elastic fiber according to claim 1, wherein The relative viscosity of the nylon 6 is 2.4-2.7; and / or, the relative viscosity of the nylon 6 elastomer is 2.1-2.6; And / or, the hardness of the nylon 6 elastomer is 25-75D; And / or, the melting point of the nylon 6 elastomer is 170-215°C.

6. A method for preparing a composite elastic fiber, characterized in that: The preparation method comprises: (1) reacting caprolactam, polyether or polyetheramine, a capping agent, a catalyst, and a stabilizer in water to obtain a nylon 6 elastomer; (2) Nylon 6 is used as component A; the nylon 6 elastomer obtained in step (1) is used as component B; and a parallel hollow bicomponent composite elastic fiber is obtained through melt extrusion, dual-channel parallel composite spinning, composite hollow spinning, cooling, stretching, heat setting and winding.

7. The preparation method according to claim 6, wherein The reaction comprises: first heating to 150-200° C. for reaction for 2-5 hours, then reacting at 180-240° C. for 4-7 hours, and then vacuum polycondensing at 220-265° C. and (-0.09) MPa; and / or, the processing temperature of component A is 265-285°C, preferably 270-280°C; And / or, the processing temperature of component B is 260-295°C, preferably 265-285°C.

8. The preparation method according to claim 6, wherein The polyether or polyetheramine is selected from one or more of polytetrahydrofuran, polypropylene glycol, polyethylene glycol, amino-terminated polyoxypropylene ether and amino-terminated polyoxyethylene ether; And / or, the number average molecular weight of the polyether or polyetheramine is 1500-3000 g / mol.

9. The preparation method according to claim 6, wherein The component B further contains nylon 6; based on the total weight of the component B, the content of nylon 6 in the component B is 0-30wt%; and / or, the end-capping agent is selected from one or more of adipic acid, sebacic acid, terephthalic acid, cyclohexanedicarboxylic acid and benzoic acid; And / or, the catalyst is selected from one or more of phosphoric acid, antimony glycol, antimony trioxide and tetrabutyl titanate.

10. The preparation method according to claim 6, wherein The stretching ratio is 1.2-3, and the stretching temperature is 60°C-110°C.

11. The composite elastic fiber prepared by the preparation method according to any one of claims 6 to 10.

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