Parallel nylon elastomer composite fiber and preparation method thereof

Abstract

The invention provides a parallel nylon elastomer composite fiber. The parallel nylon elastomer composite fiber is prepared from modified nylon 6 and a modified nylon elastomer, the modified nylon 6 is prepared according to the following steps: carrying out ring-opening reaction on caprolactam, titanium dioxide, terephthalic acid and rare earth stearate to obtain an initial polymer; performing condensation polymerization on the initial polymer to obtain modified nylon 6; the modified nylon elastomer is prepared according to the following method: mixing modified nylon 6, polyether polyol, polyether amine and 4, 4 '-diphenylmethane diisocyanate through double screws, reacting, extruding, granulating, and tackifying to obtain the modified nylon elastomer. According to the parallel nylon elastomer composite fiber, the modified nylon and the modified nylon elastomer which have good compatibility are introduced to form the elastic composite fiber with a spiral structure, and finally the breaking strength, the breaking elongation, the thermal stability and the moisture absorption performance of the composite fiber all meet the requirements of textile fibers.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon, in particular to a parallel nylon elastomer composite fiber and a preparation method thereof. Background Art

[0002] Spandex (polyurethane fiber) is a synthetic fiber with ultra-high elasticity. It is a block copolymer with alternating soft and hard segments, formed by the reaction of polyether / polyester polyols and diisocyanates. Although spandex offers high elasticity and good resilience, it cannot be used alone and has poor UV and chemical resistance. Therefore, ammonia-free elastic fibers are a key research and development focus in the textile industry. Fabrics woven from T400 and T800 parallel elastic fibers are highly popular for their excellent elasticity and pleasant feel, and are presented in the form of special polyester.

[0003] Nylon (polyamide fiber) boasts excellent thermal conductivity and wear resistance, and its usage has been growing rapidly annually. Nylon elastomers (TPAE) are a high-performance material that combines the high strength of nylon with rubber-like elasticity through molecular structural design, introducing a polyether soft segment within the nylon (polyamide) hard segment. Nylon elastomers are widely used, for example, in automotive manufacturing for chassis protection panels and other components, in electronics and electrical equipment for device casings and cable insulation, in construction as door and window sealing materials, and in the medical field for biocompatibility in artificial joints, catheters, and other devices. They also have applications in sporting goods, electronic accessories, and industrial components.

[0004] However, nylon elastomers are rarely used in the field of textiles and clothing. Patents CN114381815A, CN114182370A, and CN110067041A use nylon elastomers to prepare fibers. Specifically, Chinese patent No. CN114381815 prepares nylon elastomer 55-660dtex monofilaments by controlling the ratio of hard segments to soft segments of nylon elastomers. The monofilaments of this solution are only suitable for use in special fields because of their coarse specifications. Chinese patent No. CN114182370A discloses a method of preparing fibers by mixing PA6 with nylon. Elastomer composite preparation of sheath-core fiber, in this solution, PA6 and nylon elastomer are not modified, the compatibility between the two is poor during the spinning process and the two-component fiber is greatly thermally degraded during the spinning process; the Chinese patent with publication number CN110067041A will extrude two or more thermoplastic elastomers from the spinneret and then slowly cool and then force cool to produce wear-resistant elastic fiber. This solution of first slow cooling and then force cooling is somewhat difficult to implement in industrialization; moreover, the fibers finally prepared by the above three solutions all have the problems of low fiber strength and large elongation at break, which are difficult to apply in the field of textiles and clothing. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a parallel nylon elastomer composite fiber. The composite fiber provided by the present application has high breaking strength, excellent elastic elongation and recovery performance. Furthermore, the composite fiber provided by the present application has good moisture absorption performance.

[0006] In view of this, the present application provides a parallel nylon elastomer composite fiber prepared from modified nylon 6 and modified nylon elastomer;

[0007] The preparation method of the modified nylon 6 comprises the following steps:

[0008] Caprolactam, titanium dioxide, terephthalic acid and rare earth stearate are subjected to a ring-opening reaction to obtain an initial polymer;

[0009] subjecting the initial polymer to a polycondensation reaction to obtain modified nylon 6;

[0010] The preparation method of the modified nylon elastomer comprises the following steps:

[0011] The modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate are mixed and reacted through a twin-screw extruder, extruded and pelletized, and then thickened to obtain a modified nylon elastomer.

[0012] In some specific embodiments, the mass ratio of the modified nylon 6 to the modified nylon elastomer is 1:1.

[0013] In some specific embodiments, in the preparation method of modified nylon 6, based on the total mass of caprolactam, titanium dioxide, terephthalic acid and rare earth stearate, the content of caprolactam is 93-97%, the content of titanium dioxide is 0.1-0.3%, the content of terephthalic acid is 1-3%, and the content of rare earth stearate is 1-4%.

[0014] In some specific embodiments, in the preparation method of modified nylon 6, the temperature of the ring-opening reaction is 250-300°C, the pressure of the ring-opening reaction is 1-5 bar, and the time of the ring-opening reaction is 1-5 hours; and / or, the temperature of the polycondensation reaction is 200-260°C, the pressure of the polycondensation reaction is 1.05-1.15 bar, and the time of the polycondensation reaction is 10-15 hours.

[0015] In some specific embodiments, the modified nylon 6 has a relative viscosity of 2.0 to 2.5, a melting point of 215 to 225° C., and an amino content of 40 to 46 mmol / kg.

[0016] In some specific embodiments, in the preparation method of the modified nylon elastomer, based on the total mass of modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate, the content of the modified nylon 6 is 50-60%, the content of the polyether polyol is 10-30%, the content of the polyether amine is 5-10%, and the content of the 4,4'-diphenylmethane diisocyanate is 15-20%.

[0017] In some specific embodiments, the reaction temperature of the twin screw is 200-280°C, the rotation speed of the twin screw is 300-500 r / min, and / or the viscosity increasing is carried out in a vacuum drum device, the temperature of the vacuum drum device is 50-100°C, the rotation speed is 5-10 r / min, and the viscosity increasing time is 24-36h.

[0018] In some specific embodiments, the modified nylon elastomer has a relative viscosity of 2.5 to 3.0 and a melting point of 200 to 220°C.

[0019] The present application also provides a method for preparing a parallel nylon elastomer composite fiber, comprising the following steps:

[0020] S1, ring-opening polymerization of caprolactam, titanium dioxide, terephthalic acid and rare earth stearate to obtain an initial polymer;

[0021] The initial polymer is subjected to a polycondensation reaction, and after the reaction is completed, it is extruded and pelletized to obtain modified nylon 6;

[0022] S2, mixing the modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate through a twin-screw extruder, extruding and pelletizing, drying and viscosity-increasing to obtain a modified nylon elastomer;

[0023] S3, melt-extrude the modified nylon 6 and the modified nylon elastomer in a single-screw machine respectively, then merge and spray out from the spinneret of the spinning manifold, and finally cool, oil, draw and shape, and wind in sequence to obtain parallel nylon elastomer composite fibers.

[0024] In some specific embodiments, in step S3, the melting temperature of the modified nylon 6 in the single-screw machine is 240-260°C, and / or the melting temperature of the modified nylon elastomer in the single-screw extruder is 230-250°C, and / or the mass ratio of the extruded modified nylon 6 to the extruded modified nylon elastomer is 1:1, and / or the drawing temperature is 70-90°C, and / or the setting temperature is 140-160°C, and / or the drawing-setting ratio is 1.5-3.0, and / or the winding speed is 3000-4000 r / min.

[0025] The present application provides a parallel nylon elastomer composite fiber, which is prepared from modified nylon 6 and a modified nylon elastomer, wherein the modified nylon 6 is copolymerized with a rare earth stearate to modify the nylon 6, and the modified nylon elastomer is prepared using the modified nylon 6 as a carrier, so that the modified nylon 6 and the modified nylon elastomer have excellent compatibility, ensuring the smooth progress of the spinning process while ensuring the performance of the composite fiber, and the use of rare earth stearate to modify the above two components improves the thermal stability of the composite fiber, ultimately making the composite fiber have high breaking strength, excellent elastic elongation and recovery properties, and good moisture absorption properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a cross-sectional photograph of the parallel nylon elastomer composite fiber prepared in this example;

[0027] Figure 2 This is a side view of the parallel nylon elastomer composite fiber prepared in this example. DETAILED DESCRIPTION

[0028] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0029] In view of the performance requirements of nylon elastomer fibers for fiber strength and elongation at break, the present application provides a parallel nylon elastomer composite fiber, which introduces modified nylon (PA6) and modified nylon elastomer (TPAE) with good compatibility. The modified PA6 improves the rigid support in the parallel nylon elastomer composite material, and the modified TPAE provides elastic support. By utilizing the relative viscosity difference and shrinkage difference between the two, an elastic composite fiber with a spiral structure is formed. Ultimately, the fiber strength, elongation at break, thermal stability and moisture absorption properties of the composite fiber meet the requirements of textile fiber post-weaving. Specifically, the present application provides a parallel nylon elastomer composite fiber prepared from modified nylon 6 and modified nylon elastomer;

[0030] The preparation method of the modified nylon 6 comprises the following steps:

[0031] Caprolactam, titanium dioxide, terephthalic acid and rare earth stearate are subjected to a ring-opening reaction to obtain an initial polymer;

[0032] subjecting the initial polymer to a polycondensation reaction to obtain modified nylon 6;

[0033] The preparation method of the modified nylon elastomer comprises the following steps:

[0034] The modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate are mixed and reacted through a twin-screw extruder, extruded and pelletized, and then thickened to obtain a modified nylon elastomer.

[0035] In the parallel nylon elastomer composite fiber provided in the present application, the mass ratio of the modified nylon 6 to the modified nylon elastomer is 1:1; the modified nylon 6 and the modified nylon elastomer in the above mass ratio have the best breaking strength and elastic properties.

[0036] In the present application, the modified nylon 6 is stearic acid rare earth salt copolymer modified nylon 6, which is obtained by a two-step reaction; first, caprolactam, titanium dioxide, terephthalic acid and stearic acid rare earth salt are subjected to a ring-opening reaction to obtain an initial polymer. Chemical fiber spinning is a high-temperature process. If the thermal stability of the molten slurry is poor, the following problems will occur: ① After the molten slurry is spun from the spinneret, the probability of floating yarn and broken yarn increases; floating yarn affects product quality, and broken yarn affects continuous production; ② The fiber breaking strength is low, and the yarn often breaks during the weaving process, resulting in many defects on the cloth surface and affecting the weaving efficiency; In summary, it is very important to improve the thermal stability of the molten slurry during the spinning process; the rare earth ions in the modified nylon 6 form coordination bonds with the amide groups in the polyamide molecular chain, which greatly reduces the breakage of the molecular chain at high temperature, thereby improving the thermal stability of the composite fiber; the rare earth stearate is also called rare earth stearate, and an example thereof is a mixture of one or more of lanthanum stearate, cerium stearate, yttrium stearate, samarium stearate, and neodymium stearate. Based on the total mass of caprolactam, titanium dioxide, terephthalic acid and rare earth stearate, the caprolactam content is 93-97%, the titanium dioxide content is 0.1-0.3%, the terephthalic acid content is 1-3%, and the rare earth stearate content is 1-4%. Specifically, the caprolactam content is 94-95%, the titanium dioxide content is 0.2-0.3%, the terephthalic acid content is 1.5-2.5%, and the rare earth stearate content is 1.2-3.7%. The ring-opening reaction temperature is 250-300°C, the pressure is 1-5 bar, and the reaction time is 1-5 hours. Specifically, the ring-opening reaction temperature is 260-280°C, the pressure is 2-3 bar, and the reaction time is 2-3 hours.

[0037] According to the present invention, the initial polymer obtained above is then subjected to a polycondensation reaction to obtain modified nylon 6, wherein the temperature of the polycondensation reaction is 200-260°C, the pressure of the polycondensation reaction is 1.05-1.15 bar, and the time of the polycondensation reaction is 10-15 hours; specifically, the temperature of the polycondensation reaction is 220-245°C, the pressure of the polycondensation reaction is 1.05-1.10 bar, and the time of the polycondensation reaction is 12-14 hours.

[0038] The modified nylon 6 prepared in this application has a relative viscosity of 2.0 to 2.5, a melting point of 215 to 225°C, and an amino content of 40 to 46 mmol / kg. Specifically, the modified nylon 6 has a relative viscosity of 2.2 to 2.4, a melting point of 220 to 225°C, and an amino content of 44 to 45 mmol / kg. The relative viscosity of the modified nylon 6 affects the breaking strength of the fiber, while the amino group affects the dyeing process. The above relative viscosity of the modified nylon 6 prepared in this application ensures that the composite fiber has good breaking strength.

[0039] The modified nylon elastomer described in this application is prepared using the modified nylon 6 as a carrier to prepare a modified nylon elastomer (modified TPAE). Specifically, the modified nylon 6, polyether polyol, polyether amine, and 4,4'-diphenylmethane diisocyanate are mixed and reacted in a twin-screw extruder, extruded, pelletized, and then viscosified to obtain the modified nylon elastomer. During this process, an appropriate amount of polyether amine is introduced. The terminal amino groups of the polyether amine can improve the hydrophilicity of the fiber, imparting a good feel and moisture absorption properties. The modified TPAE is prepared using the modified nylon 6 as a carrier, ensuring good compatibility with the modified nylon 6. The polyether amine is well known to those skilled in the art. In specific embodiments, the polyether amine is selected from polyethylene glycol diamine. The polyether polyol is well known to those skilled in the art. In specific embodiments, the polyether polyol is selected from polytetramethylene glycol. Based on the total mass of modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate, the content of the modified nylon 6 is 50-60%, the content of the polyether polyol is 10-30%, the content of the polyether amine is 5-10%, and the content of the 4,4'-diphenylmethane diisocyanate is 15-20%. Specifically, the content of the modified nylon 6 is 55-58%, the content of the polyether polyol is 20-25%, the content of the polyether amine is 7-9%, and the content of the 4,4'-diphenylmethane diisocyanate is 17-19%. The reaction temperature of the twin screw is 200-280°C, and the rotation speed of the twin screw is 300-500 r / min. Specifically, the reaction temperature of the twin screw is 230-260°C, and the rotation speed of the twin screw is 350-450 r / min. More specifically, the reaction temperature of the twin screw is 240-250°C, and the rotation speed of the twin screw is 380-420 r / min. In order to ensure the elasticity of the composite fiber, the relative viscosity difference between the modified TPAE and the modified PA6 needs to be within a certain range. The viscosity increase described in this application is carried out in a vacuum drum device to increase the relative viscosity of the modified PA6; the temperature of the vacuum drum device is 50-100°C, the rotation speed is 5-10 r / min, and the viscosity increase time is 24-36 hours. Specifically, the temperature of the vacuum drum device is 60-80°C, the rotation speed is 6-8 r / min, and the viscosity increase time is 24-30 hours.

[0040] The modified TPAE prepared above has a relative viscosity of 2.5-3.0 and a melting point of 200-220° C.; specifically, the modified TPAE prepared above has a relative viscosity of 2.8-3.0 and a melting point of 200-210° C.

[0041] Furthermore, the present application provides a method for preparing a parallel nylon elastomer composite fiber, comprising the following steps:

[0042] S1, ring-opening polymerization of caprolactam, titanium dioxide, terephthalic acid and rare earth stearate to obtain an initial polymer;

[0043] The initial polymer is subjected to a polycondensation reaction, and after the reaction is completed, it is extruded and pelletized to obtain modified nylon 6;

[0044] S2, mixing the modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate through a twin-screw extruder, extruding and pelletizing, drying and viscosity-increasing to obtain a modified nylon elastomer;

[0045] S3. The modified nylon 6 and the modified nylon elastomer are melt-extruded separately in a single-screw machine, and then sprayed out from the spinneret of a spinning manifold. Finally, they are cooled, oiled, drawn and shaped, and wound in sequence to obtain parallel nylon elastomer composite fibers.

[0046] In the process of preparing the parallel nylon elastomer composite fiber, stearic acid rare earth salt copolymer modified PA6 is first prepared, then modified TPAE is prepared, and finally the above two are composite spun to form the parallel nylon elastomer composite fiber.

[0047] Specifically, in the process of preparing modified PA6, the above-mentioned ring-opening polymerization and the above-mentioned polycondensation reaction have been described in detail and will not be repeated here; in a specific embodiment, the ring-opening reaction is carried out in a prepolymerization kettle, and the polycondensation reaction is carried out in a normal pressure continuous polymerization reactor. After the polycondensation reaction is completed, the reaction is stopped after the stirring current and the online viscometer value reach preset values.

[0048] In the process of preparing modified TPAE, the above raw materials and reaction process have been described in detail and will not be repeated here.

[0049] After preparing the modified PA6 and modified TPAE, they are melt-extruded separately in a single-screw extruder, then combined and ejected from the spinneret of a spinning manifold. Finally, they are cooled, oiled, drawn and shaped, and wound in sequence to obtain a parallel nylon elastomer composite fiber. In this process, the mass ratio of the modified PA6 to the modified TPAE is 1:1. The melting temperature of the modified nylon 6 in the single-screw extruder is 240-260°C, and the melting temperature of the modified nylon elastomer in the single-screw extruder is 230-250°C. Specifically, the melting temperature of the modified PA6 in the single-screw extruder is 245-255°C, and the melting temperature of the modified TPAE in the single-screw extruder is 235-245°C. The modified PA6 and the modified TPAE have good compatibility. After being melted separately, they are combined and ejected from the spinneret of the spinning manifold to obtain an initial composite fiber with a peanut-shaped parallel structure in cross section. Finally, the initial composite fiber is cooled, oiled, drawn and shaped, and wound; wherein, the cooling is performed by blowing air, the drawing temperature is 70-90°C, the setting temperature is 140-160°C, the drawing and setting ratio is 1.5-3.0, and the winding speed is 3000-4000 r / min; specifically, the drawing temperature is 80-85°C, the setting temperature is 145-155°C, the drawing and setting ratio is 2.0-2.5, and the winding speed is 3500-4000 r / min.

[0050] The parallel nylon elastomer composite fiber provided by the present invention and the preparation method thereof adopts stearic acid rare earth salt to modify PA6, and uses stearic acid rare earth salt copolymerized modified PA6 as a carrier to prepare modified TPAE, and then the two are compositely spun. Due to the excellent compatibility between the two, it is ensured that the spinning process will not have the phenomenon of sticking to the plate, abnormal yarn output, etc.; the present application belongs to the spinning of two-component filaments. Compared with the spinning process of single-component filaments and two-component filaments of the same specifications, the time of each component of the two-component filament in the melt pipe is twice that of the single-component melt in the melt pipe. The increase in time leads to greater thermal degradation of the two-component melt in the pipe, which ultimately leads to The use of rare earth stearate to modify the two components greatly reduces the breakage of the molecular chain at high temperatures, thereby improving the thermal stability of the material and effectively improving the spinning condition. At the same time, the modified TPAE is prepared using polyetheramine. The terminal amino group of the polyetheramine can increase the hydrophilicity of the fiber, making the final fabric have a better feel and moisture absorption performance. The parallel nylon elastomer composite fiber prepared in this application has high breaking strength, good elastic elongation and recovery, and can be well applied to the textile and clothing field. In addition, the use of a twin-screw to prepare TPAE is more flexible and convenient than traditional copolymerization.

[0051] In order to further understand the present invention, the parallel nylon elastomer composite fiber and the preparation method thereof provided by the present invention are described in detail below with reference to the examples. The protection scope of the present invention is not limited by the following examples.

[0052] Example 1

[0053] (1) Preparation of stearic acid rare earth salt copolymer modified PA6: Synthesis was carried out by a two-stage method; 93% caprolactam, 0.3% titanium dioxide, 3% terephthalic acid and 3.7% lanthanum stearate were fed into a prepolymerization reactor for ring-opening reaction at a temperature of 260°C and a pressure of 2 bar. After 3 hours, the polymer from the prepolymerization reactor was fed into a normal pressure continuous polymerization reactor through a gear pump for polycondensation reaction at a temperature of 245°C and a pressure of 1.05 bar. After 12 hours, the reaction was stopped when the stirring current and the online viscometer value reached the preset values. After extrusion, the polymer was pelletized underwater to obtain stearic acid rare earth salt copolymer modified PA6.

[0054] The relative viscosity of the rare earth stearate copolymer modified PA6 prepared above is 2.0, the melting point is 220°C, and the amino content is 45 mmol / kg;

[0055] (2) Preparation of modified TPAE: The rare earth stearate copolymer-modified PA6 prepared in step (1), polybutylene glycol, polyethylene glycol diamine and 4,4'-diphenylmethane diisocyanate are mixed in a twin-screw extruder at a mass fraction ratio of 60%, 10%, 10% and 20%, extruded and pelletized underwater, dried and then sent to a vacuum drum for viscosity increase for 24 hours to obtain a high-viscosity rare earth stearate copolymer-modified TPAE; wherein the twin-screw reaction temperature is controlled at 230-260°C, the screw speed is controlled at 300 r / min, the vacuum drum temperature is controlled at 80°C, and the speed is controlled at 8 r / min;

[0056] The modified TPAE prepared above has a relative viscosity of 3.0 and a melting point of 200°C;

[0057] (3) Preparation of parallel nylon elastomer composite fibers: The stearic acid rare earth salt copolymer modified PA6 prepared in step (1) and the modified TPAE prepared in step (2) are dried and sent to their respective single screw machines for melt extrusion, filtered through CPF and metering pumps, and sprayed out from the spinneret of the spinning box, and then cooled, blown, oiled, stretched and shaped, and wound to obtain parallel nylon elastomer composite fibers; wherein the screw melting temperature of the modified PA6 is 240-260°C, the screw melting temperature of the stearic acid rare earth salt copolymer modified TPAE is 230-250°C, the mass ratio of the two extruded by their respective metering pumps is 50:50, the stretching temperature is 80°C, the shaping temperature is 150°C, the stretching and shaping ratio is 2.5, and the winding speed is 3800r / min.

[0058] Figure 1 This is a cross-sectional photograph of the parallel nylon elastomer composite fiber prepared in this embodiment. Figure 2 This is a side view of the parallel nylon elastomer fibers prepared in this embodiment; as can be seen from the figure, the composite fibers prepared in this application have a peanut-shaped parallel structure.

[0059] Example 2

[0060] (1) Preparation of stearic acid rare earth salt copolymer modified PA6: Synthesis was carried out by a two-stage method; 95% caprolactam, 0.3% titanium dioxide, 3% terephthalic acid and 1.7% rare earth lanthanum stearate were fed into a prepolymerization reactor for ring-opening reaction at a temperature of 260°C and a pressure of 2 bar. After 3 hours, the polymer from the prepolymerization reactor was fed into a normal pressure continuous polymerization reactor through a gear pump for polycondensation reaction at a temperature of 245°C and a pressure of 1.05 bar. After 12 hours, the reaction was stopped when the stirring current and the online viscometer value reached the preset values. After extrusion, the polymer was pelletized underwater to obtain stearic acid rare earth salt copolymer modified PA6.

[0061] The relative viscosity of the rare earth stearate copolymer modified PA6 prepared above is 2.2, the melting point is 220°C, and the amino content is 44 mmol / kg;

[0062] (2) Preparation of modified TPAE: The rare earth stearate copolymer modified PA6 prepared in step (1), polybutylene glycol, polyethylene glycol diamine and 4,4'-diphenylmethane diisocyanate are mixed in a twin-screw extruder at a mass fraction ratio of 55%, 20%, 10% and 15%, extruded and pelletized underwater, dried and then sent to a vacuum drum for viscosity increase for 30 hours to obtain a high-viscosity rare earth stearate copolymer modified TPAE; wherein the twin-screw reaction temperature is controlled at 230-260°C, the screw speed is controlled at 300 r / min, the vacuum drum temperature is controlled at 80°C, and the speed is controlled at 8 r / min;

[0063] The modified TPAE prepared above has a relative viscosity of 3.0 and a melting point of 200°C;

[0064] (3) Preparation of parallel nylon elastomer composite fibers: The stearic acid rare earth salt copolymer modified PA6 prepared in step (1) and the modified TPAE prepared in step (2) are dried and sent to their respective single screw machines for melt extrusion, filtered through CPF and metering pumps, and sprayed out from the spinneret of the spinning box, and then cooled, blown, oiled, stretched and shaped, and wound to obtain parallel nylon elastomer composite fibers; wherein the screw melting temperature of the modified PA6 is 240-260°C, the screw melting temperature of the stearic acid rare earth salt copolymer modified TPAE is 230-250°C, the mass ratio of the two extruded by their respective metering pumps is 50:50, the stretching temperature is 80°C, the shaping temperature is 150°C, the stretching and shaping ratio is 2.5, and the winding speed is 3800r / min.

[0065] Example 3

[0066] (1) Preparation of stearic acid rare earth salt copolymer modified PA6: Synthesis was carried out by a two-stage method; 97% caprolactam, 0.3% titanium dioxide, 1.5% terephthalic acid and 1.2% rare earth lanthanum stearate were fed into a prepolymerization reactor for ring-opening reaction at a temperature of 260°C and a pressure of 2 bar. After 3 hours, the polymer from the prepolymerization reactor was fed into a normal pressure continuous polymerization reactor through a gear pump for polycondensation reaction at a temperature of 245°C and a pressure of 1.05 bar. After 12 hours, the reaction was stopped when the stirring current and the online viscometer value reached the preset values. After extrusion, the polymer was pelletized underwater to obtain stearic acid rare earth salt copolymer modified PA6.

[0067] The relative viscosity of the rare earth stearate copolymer modified PA6 prepared above is 2.5, the melting point is 220°C, and the amino content is 45 mmol / kg;

[0068] (2) Preparation of modified TPAE: The rare earth stearate copolymer modified PA6 prepared in step (1), polybutylene glycol, and polyethylene glycol diamine 4,4'-diphenylmethane diisocyanate are mixed in a twin-screw extruder at a mass fraction ratio of 50%, 30%, 5%, and 15%, and then pelletized underwater after extrusion. After drying, the mixture is sent to a vacuum drum for viscosity increase for 24 hours to obtain a high-viscosity rare earth stearate copolymer modified TPAE; wherein the twin-screw reaction temperature is controlled at 230-260°C, the screw speed is controlled at 300 r / min, the vacuum drum temperature is controlled at 80°C, and the speed is controlled at 8 r / min;

[0069] The modified TPAE prepared above has a relative viscosity of 3.0 and a melting point of 200°C;

[0070] (3) Preparation of parallel nylon elastomer elastic fiber: The stearic acid rare earth salt copolymer modified PA6 prepared in step (1) and the modified TPAE prepared in step (2) are dried and sent to their respective single screw machines for melt extrusion, filtered by CPF and metering pump, and sprayed out from the spinneret of the spinning box, and then cooled, blown, oiled, stretched and shaped, and wound to obtain parallel nylon elastomer composite fiber; wherein the melting temperature of the modified PA6 screw is 240-260°C, the melting temperature of the stearic acid rare earth salt copolymer modified TPAE screw is 230-250°C, the mass ratio of the two extruded by their respective metering pumps is 50:50, the stretching temperature is 80°C, the shaping temperature is 150°C, the stretching and shaping ratio is 2.5, and the winding speed is 3800r / min.

[0071] Comparative Example: PA6 is not modified, and modified TPAE is prepared using ordinary PA6

[0072] (1) Preparation of modified TPAE: Conventional PA6, polyether polyol, polyether amine, and 4,4'-diphenylmethane diisocyanate were mixed in a twin-screw extruder at a mass fraction ratio of 50%, 30%, 5%, and 15%, respectively. After extrusion, the mixture was pelletized underwater, dried, and then subjected to vacuum drum viscosification for 24 hours to obtain high-viscosity stearic acid rare earth salt copolymer-modified TPAE. The twin-screw reaction temperature was controlled at 230-260°C, the screw speed was controlled at 300 r / min, and the vacuum drum temperature was controlled at 80°C, and the speed was controlled at 8 r / min.

[0073] The modified TPAE prepared above has a relative viscosity of 3.0 and a melting point of 200°C;

[0074] (2) Preparation of parallel nylon elastomer composite fibers: Conventional PA6 and the modified TPAE obtained in step (1) are dried and sent to their respective single-screw machines for melt extrusion, filtered and metered by CPF, sprayed out from the spinning plate of the spinning box, and then cooled, blown, oiled, stretched and shaped, and wound to obtain parallel nylon elastomer composite fibers; wherein, the melting temperature of the conventional PA6 screw is 240-260°C, the melting temperature of the modified TPAE screw is 230-250°C, the mass ratio of the two extruded by their respective metering pumps is 50:50, the stretching temperature is 80°C, the shaping temperature is 150°C, the stretching and shaping ratio is 2.5, and the winding speed is 3800r / min; in the above process, it is difficult to produce silk, there are many floating silks, and the breakage rate is high.

[0075] The testing methods of the parallel nylon elastomer composite fibers and fabrics thereof prepared in the above examples and comparative examples are described as follows:

[0076] The fiber fineness test is carried out in accordance with the national standard GB / T 14343-2008;

[0077] The breaking strength and elongation tests were carried out in accordance with the standard GB / T 14344-2008;

[0078] The elastic elongation and elastic recovery of fabrics made of fibers are tested according to ASTM D3107.

[0079] The moisture absorption performance of fabrics made of fibers is tested in accordance with standard GB / T 21655.2-2019.

[0080] The parallel nylon elastomer composite fibers prepared in the examples and comparative examples were tested using the above-mentioned testing methods. The main performance test data of the parallel nylon elastomer composite fibers and their fabrics prepared in the examples and comparative examples are shown in Table 1.

[0081] Table 1 Performance data of parallel nylon elastomer composite fibers prepared in Examples and Comparative Examples

[0082]

[0083] Table 2 Hygroscopicity data of parallel nylon elastomer composite fibers prepared in Examples and Comparative Examples

[0084]

[0085]

[0086] It can be seen from Tables 1 and 2 that, compared with Example 3, the nylon 6 in the parallel nylon elastomer composite fiber prepared in Comparative Example 1 was not modified, which ultimately affected the breaking strength, elastic recovery and moisture absorption properties of the parallel nylon elastomer composite fiber.

[0087] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0088] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A parallel nylon elastomer composite fiber prepared from modified nylon 6 and modified nylon elastomer; The preparation method of the modified nylon 6 comprises the following steps: Caprolactam, titanium dioxide, terephthalic acid and rare earth stearate are subjected to a ring-opening reaction to obtain an initial polymer; subjecting the initial polymer to a polycondensation reaction to obtain modified nylon 6; The preparation method of the modified nylon elastomer comprises the following steps: The modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate are mixed and reacted through a twin-screw extruder, extruded and pelletized, and then thickened to obtain a modified nylon elastomer.

2. The parallel nylon elastomer composite fiber according to claim 1, characterized in that The mass ratio of the modified nylon 6 to the modified nylon elastomer is 1:

1.

3. The parallel nylon elastomer composite fiber according to claim 1 or 2, characterized in that In the preparation method of modified nylon 6, based on the total mass of caprolactam, titanium dioxide, terephthalic acid and rare earth stearate, the content of caprolactam is 93-97%, the content of titanium dioxide is 0.1-0.3%, the content of terephthalic acid is 1-3%, and the content of rare earth stearate is 1-4%.

4. The parallel nylon elastomer composite fiber according to claim 3, characterized in that In the preparation method of modified nylon 6, the temperature of the ring-opening reaction is 250-300°C, the pressure of the ring-opening reaction is 1-5 bar, and the time of the ring-opening reaction is 1-5 hours; and / or the temperature of the polycondensation reaction is 200-260°C, the pressure of the polycondensation reaction is 1.05-1.15 bar, and the time of the polycondensation reaction is 10-15 hours.

5. The parallel nylon elastomer composite fiber according to claim 1 or 4, characterized in that The modified nylon 6 has a relative viscosity of 2.0 to 2.5, a melting point of 215 to 225° C., and an amino content of 40 to 46 mmol / kg.

6. The parallel nylon elastomer composite fiber according to claim 5, characterized in that In the preparation method of the modified nylon elastomer, based on the total mass of modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate, the content of the modified nylon 6 is 50-60%, the content of the polyether polyol is 10-30%, the content of the polyether amine is 5-10%, and the content of the 4,4'-diphenylmethane diisocyanate is 15-20%.

7. The parallel nylon elastomer composite fiber according to claim 1 or 6, characterized in that The reaction temperature of the twin screw is 200-280° C., the rotation speed of the twin screw is 300-500 r / min, and / or the viscosity increasing is carried out in a vacuum drum device, the temperature of the vacuum drum device is 50-100° C., the rotation speed is 5-10 r / min, and the viscosity increasing time is 24-36 hours.

8. The parallel nylon elastomer composite fiber according to claim 7, characterized in that The modified nylon elastomer has a relative viscosity of 2.5 to 3.0 and a melting point of 200 to 220°C.

9. A method for preparing a parallel nylon elastomer composite fiber, comprising the following steps: S1, ring-opening polymerization of caprolactam, titanium dioxide, terephthalic acid and rare earth stearate to obtain an initial polymer; The initial polymer is subjected to a polycondensation reaction, and after the reaction is completed, it is extruded and pelletized to obtain modified nylon 6; S2, mixing the modified nylon 6, polyether polyol, polyether amine and 4,4'-diphenylmethane diisocyanate through a twin-screw extruder, extruding and pelletizing, drying and viscosity-increasing to obtain a modified nylon elastomer; S3, melt-extrude the modified nylon 6 and the modified nylon elastomer in a single-screw machine respectively, then merge and spray out from the spinneret of the spinning manifold, and finally cool, oil, draw and shape, and wind in sequence to obtain parallel nylon elastomer composite fibers.

10. The preparation method according to claim 9, characterized in that In step S3, the melting temperature of the modified nylon 6 in the single-screw machine is 240-260°C, and / or the melting temperature of the modified nylon elastomer in the single-screw extruder is 230-250°C, and / or the mass ratio of the extruded modified nylon 6 and the extruded modified nylon elastomer is 1:1, and / or the drawing temperature is 70-90°C, and / or the setting temperature is 140-160°C, and / or the drawing-setting ratio is 1.5-3.0, and / or the winding speed is 3000-4000 r / min.

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