High-tear-resistance chinlon-polyester double-layer composite fiber and preparation method thereof

Abstract

The invention relates to the technical field of functional fibers, and discloses a high-tear-resistance chinlon-polyester double-layer composite fiber and a preparation method thereof. The high-tear-resistance chinlon-polyester double-layer composite fiber is composed of a skin layer material and a core layer material. The skin layer material is prepared from the following raw materials in parts by weight: 80 to 100 parts of polyamide 6 slices, 2 to 5 parts of a modified reinforcing agent, 0.1 to 0.6 part of an antioxidant 1098 and 0.1 to 0.4 part of zinc stearate; the core layer material comprises the following raw materials in parts by weight: 100 parts of polyester chips, 5-15 parts of a hydrophilic modifier and 0.5-2 parts of a cross-linking agent; the core layer material is coated with the skin layer material, the core layer material accounts for 40-70 parts by weight, and the skin layer material accounts for 40-70 parts by weight. The modified reinforcing agent provided by the invention can improve the tear strength of the fiber and prevent the problems of damage, deformation and the like of the fiber under the conditions of long-term use or extreme stress; the hydrophilic modifier can endow the fiber with hydrophilicity.

Description

Technical Field

[0001] This invention relates to the field of functional fiber technology, specifically to a high tear-resistant nylon-polyester bilayer composite fiber and its preparation method. Background Technology

[0002] Core-sheath composite fibers represent a significant achievement in composite spinning technology. Through conjugated spinning, two polymers with different properties form the sheath and core layers of the fiber, respectively, achieving multiple properties that are difficult to achieve with a single fiber. The core advantage of this type of fiber lies in its ability to flexibly match the sheath and core material combinations according to application requirements. Through synergistic and complementary interlayer properties, it overcomes the performance limitations of single polymer fibers, and is widely used in textiles, apparel, industrial filtration, and safety protection. Nylon and polyester fibers, as two core categories in the synthetic fiber field, have achieved widespread application since industrialization due to their excellent comprehensive properties. Nylon fibers possess excellent breaking strength, elastic recovery rate, and abrasion resistance, while polyester fibers have advantages such as excellent dimensional stability, chemical corrosion resistance, and cost-effectiveness. The core design logic of nylon-polyester bilayer composite fibers is to achieve complementary properties, that is, to leverage the excellent tear resistance of nylon and the excellent dimensional stability and chemical corrosion resistance of polyester to form a synergistic advantage. This is expected to overcome the application limitations of single fibers, but many technical challenges remain in the research and development process. Regarding tear resistance, the industry currently achieves this by introducing modified additives into nylon. However, commonly used inorganic additives tend to agglomerate in the nylon matrix, leading to fluctuations in local fiber properties and affecting the overall mechanical stability of the fiber. Furthermore, while nylon is more hydrophilic than polyester, both are hydrophobic fibers, which can cause problems such as stuffiness and static electricity buildup when worn.

[0003] Patent application number 202011249990.4 discloses a core-sheath structure absorbent fiber and its preparation method. By attaching a layer of sericin to the surface of cellulose nanocrystals, the absorbency of polyester fiber is improved. However, sericin is sensitive to temperature and pH, and is prone to denaturation, affecting product durability. Patent application number 202311006882.8 discloses a lightweight functional composite fabric and its manufacturing process. By introducing sodium palmitate, sodium gluconate, and polyurethane to construct a core reinforcement system, the fabric's tear resistance is significantly improved. However, modified hydrotalcite and light calcium carbonate are both inorganic fillers, and their interfacial bonding with the organic polyurethane film has inherent limitations, leading to a certain decrease in tear resistance after washing. There is still room for improvement in the interfacial compatibility between the filler and the substrate. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a high tear-resistant nylon-polyester bilayer composite fiber and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A high tear-resistant nylon-polyester bilayer composite fiber, the composite fiber being composed of a sheath material and a core material; the sheath material comprising the following raw materials in parts by weight: 80-100 parts of polyamide 6 chips, 2-5 parts of modified reinforcing agent, 0.1-0.6 parts of antioxidant 1098, and 0.1-0.4 parts of zinc stearate;

[0007] The core material comprises the following raw materials in parts by weight: 100 parts polyester chips, 5-15 parts hydrophilic modifier, and 0.5-2 parts crosslinking agent;

[0008] The outer layer material covers the core layer material, with the core layer material comprising 40-70 parts by weight and the outer layer material comprising 40-70 parts by weight;

[0009] The crosslinking agent is trimethylolpropane trimethacrylate;

[0010] The modified reinforcing agent is prepared by the following steps:

[0011] Step A1: Add 3-glycidyl etheroxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran to the polymerization tube and mix them. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted in an oil bath at 70°C for 20 hours to obtain intermediate product 1.

[0012] Furthermore, the ratio of 3-glycidoxypropyltrimethoxysilane, 9-anthracarboxylic acid, and tetrahydrofuran is 3-5 mmol: 3-5 mmol: 6-10 mL;

[0013] In step A1, 3-glycidyl etheroxypropyltrimethoxysilane and 9-anthracarboxylic acid undergo a ring-opening reaction, introducing the methoxy group into the system and providing reaction conditions for the subsequent grafting reaction. Anthrayl is a rigid polycyclic aromatic structure composed of three fused benzene rings. Introducing it into the system reduces the steric hindrance effect of the anthracene group, increases the average molecular chain spacing, increases the proportion of amorphous regions, and improves the mobility of the molecular chain. During stress failure, the π-π interaction between anthracene groups also consumes energy, improving the balance between fiber toughness and rigidity and reducing the risk of stress failure.

[0014] Step A2: Mix CNC (cellulose nanocrystals), anhydrous ethanol and deionized water, sonicate for 10 min, heat to 40°C, add intermediate product 1 solution dropwise, stir for 10 h, then centrifuge, wash, vacuum dry at 50°C for 2 h, and then dry in an oven at 110°C for 2 h to promote silane self-crosslinking, to obtain intermediate product 2.

[0015] Furthermore, the ratio of CNC, anhydrous ethanol, deionized water, and intermediate product 1 solution is 0.1g: 20-30mL: 5-7.5mL: 4-8mL;

[0016] Furthermore, the intermediate product 1 solution is prepared by mixing intermediate product 1 and anhydrous ethanol in a volume ratio of 2-4 mmol: 4-8 mL;

[0017] In step A2, intermediate product 1 and CNC undergo a grafting reaction. The introduced CNC is a nano-sized organic crystal structure with advantages such as low cost, low density, and good biocompatibility. It can be used as a nucleating agent to improve the crystallization rate and crystallinity of the system. In addition, due to its high strength, it can enhance the mechanical strength of the fiber.

[0018] Step A3: Mix lauric acid, intermediate product 2 obtained in step A2, sodium bisulfate and toluene, heat in an oil bath to 120°C, reflux until anhydrous, then separate, monitor using TLC (thin-layer chromatography), cool to room temperature, add deionized water, stir for 15 min, let stand, separate, add 0.5 wt% sodium carbonate solution, stir for 15 min, let stand to separate layers, wash with water, and concentrate under vacuum to obtain the modified reinforcing agent;

[0019] Furthermore, the ratio of lauric acid, intermediate product 1 in step A2, sodium bisulfate, toluene, deionized water, and sodium carbonate solution is 2-6 mol: 1.3-3.9 mmol: 0.5-2 mol: 4-10 mL: 3-5 mL: 3-5 mL;

[0020] In step A3, intermediate product 2 and lauric acid undergo esterification. CNC, as a reinforcing filler in the system, is introduced with long carbon chains. Its high steric hindrance improves the dispersibility of CNC, and the flexible long carbon chains enable physical entanglement between CNC and nylon to form an organic "buffer layer", thereby improving interfacial compatibility. This gives CNC the ability to both strengthen and toughen, and improves the tear resistance of the fiber.

[0021] The hydrophilic modifier is prepared by the following steps:

[0022] Step B1: Sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate are mixed, heated to 150°C, maintained for 10 min, and then heated to 180°C and stirred for 2 h to obtain the sulfonate monomer.

[0023] Furthermore, the ratio of sodium dimethyl isophthalate-5-sulfonate, ethylene glycol, and zinc acetate is 0.3-0.5 mol: 0.72-1.2 mol: 0.03-0.04 g;

[0024] In step B1, sodium dimethyl isophthalate-5-sulfonate and ethylene glycol undergo transesterification to introduce hydroxyl groups into the system, providing reaction conditions for the subsequent polycondensation reaction. The introduced sulfonic acid group is a hydrophilic ionic group, which can effectively improve the hydrophilicity of the system.

[0025] Step B2: Mix the sulfonate monomer obtained in step B1, polyethylene glycol (molecular weight 2000) and antimony trioxide, heat to 250°C, seal the device and evacuate for 20 minutes, then react for 30 minutes, remove the device and obtain the hydrophilic modifier.

[0026] Furthermore, the ratio of polyethylene glycol, sodium dimethyl isophthalate-5-sulfonate in step B1, and antimony trioxide is 0.12-0.2 mol: 0.3-0.5 mol: 0.02-0.03 g;

[0027] In step B2, the sulfonate monomer and polyethylene glycol undergo a polycondensation reaction to generate a copolymer containing polyester and polyether segments. The polyester segments have a molecular structure similar to that of polyester fibers and have good compatibility, while the polyether segments extend into the air or water phase, thereby improving the hydrophilicity of the fiber.

[0028] A method for preparing a high tear-resistant nylon-polyester bilayer composite fiber includes the following steps:

[0029] Step S1: Weigh the raw materials according to the weight parts, add polyamide 6 chips, modifier, antioxidant 1098 and zinc stearate to a high-speed mixer in sequence and mix at a speed of 600-800 rpm for 10-15 minutes. Then extrude and granulate through a twin-screw extruder at an extrusion temperature of 230-240℃ to obtain the skin material.

[0030] Step S2: Mix polyester chips, crosslinking agent and hydrophilic modifier, put them into a mixer and stir for 20-30 minutes, then extrude and granulate them through a twin-screw extruder at an extrusion temperature of 220-280℃ to obtain the core material;

[0031] Step S3: Dry the core material and the sheath material at 70-90℃ until the moisture content is less than 50ppm; feed the dried core material and sheath material into two spinning systems respectively, melt them, filter them, and then input them into the core-sheath composite spinning assembly to obtain a high tear-resistant nylon-polyester bilayer composite fiber material.

[0032] Furthermore, the spinning process in step S3 is as follows: melt spinning, side blowing cooling, oiling, winding, stretching, heat setting, and cutting. The spinning process parameters are: spinning speed 3500-4000 m / min, side blowing temperature 15℃, cooling air relative humidity 75%, side blowing speed 0.4 m / min, stretching ratio 1.4, heat setting temperature 100℃, the number of spinnerets on the spinneret used for spinning is 36, the maximum temperature of the extruder is controlled at 220℃, and the speed of the extruder main unit is 500 r / min.

[0033] The beneficial effects of this invention are:

[0034] The high tear-resistant nylon-polyester bilayer composite fiber of this invention can be widely used in the production of high-end textiles and apparel, industrial textiles, protective equipment, and home textiles. Introducing a modifier during the preparation of the composite fiber significantly improves its tear resistance, preventing damage and deformation under long-term use or extreme stress conditions. By compounding a hydrophilic modifier, the hydrophobic properties of the nylon-polyester composite fiber are overcome, endowing the fiber with excellent and durable hydrophilicity and moisture-wicking properties. The composite fiber of this invention has broad application prospects in the field of high-performance textile materials.

[0035] The modified reinforcing agent of this invention first utilizes a ring-opening reaction between 3-glycidoxypropyltrimethoxysilane and 9-anthracarboxylic acid to introduce an anthracene group, a rigid polycyclic aromatic structure composed of three fused benzene rings. Introducing this anthracene group into the system reduces the packing density of the nylon molecular chains, increases the average chain spacing, and increases the proportion of amorphous regions, thereby improving the mobility of the molecular chains. During stress failure, the π-π interactions between the anthracene groups also consume energy, improving the balance between fiber toughness and rigidity and reducing the risk of stress failure. Subsequently, a grafting reaction is performed with CNC (carbon nanocrystal), introducing a nanoscale organic crystal structure with advantages such as low cost, low density, and good biocompatibility. This CNC can act as a nucleating agent to improve the crystallization rate and crystallinity of the system, and its high strength enhances the mechanical strength of the fiber. Finally, using esterification, CNC is used as a reinforcing filler in the system. By introducing long carbon chains, the high steric hindrance of CNC is used to improve the dispersibility of CNC. The flexible long carbon chains enable CNC and nylon to form an organic "buffer layer" through physical entanglement, thereby improving interfacial compatibility. This gives CNC the ability to both strengthen and toughen, and improves the tear resistance of the fiber.

[0036] The hydrophilic modifier of this invention first utilizes a transesterification reaction between sodium dimethyl isophthalate-5-sulfonate and ethylene glycol to introduce a sulfonic acid group, which is a hydrophilic ionic group that can effectively improve the hydrophilicity of the system. Finally, the sulfonate monomer and polyethylene glycol undergo a polycondensation reaction to generate a copolymer containing polyester and polyether segments. The polyester segments have a molecular structure similar to polyester fibers and exhibit good compatibility, while the polyether segments extend into the air or aqueous phase, thereby improving the hydrophilicity of the fiber. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1: The modified reinforcing agent was prepared by the following steps:

[0039] Step A1: Add 3-glycidoxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran to the polymerization tube and mix them. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted in an oil bath at 70°C for 20 hours to obtain the intermediate product 1,3-glycidoxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran in a ratio of 3 mmol:3 mmol:6 mL.

[0040] Step A2: Mix CNC, anhydrous ethanol and deionized water, sonicate for 10 min, heat to 40℃, add intermediate product 1 solution dropwise, stir for 10 h, then centrifuge, wash, vacuum dry at 50℃ for 2 h, and then dry in an oven at 110℃ for 2 h to promote silane self-crosslinking to obtain intermediate product 2. The volume ratio of CNC, anhydrous ethanol, deionized water and intermediate product 1 solution is 0.1 g: 20 mL: 5 mL: 4 mL. Intermediate product 1 solution is prepared by mixing intermediate product 1 and anhydrous ethanol at a volume ratio of 2 mmol: 4 mL.

[0041] Step A3: Mix lauric acid, intermediate product 2 obtained in step A2, sodium bisulfate, and toluene. Heat the mixture in an oil bath to 120°C and reflux until anhydrous, then separate the mixture. Monitor the reaction using TLC. Cool to room temperature, add deionized water, stir for 15 min, let stand, separate, add 0.5 wt% sodium carbonate solution, stir for 15 min, let stand to separate layers, wash with water, and concentrate under vacuum to obtain the modified reinforcing agent. The ratio of lauric acid, intermediate product 1 from step A2, sodium bisulfate, toluene, deionized water, and sodium carbonate solution is 2 mol: 1.3 mmol: 0.5 mol: 4 mL: 3 mL: 3 mL.

[0042] The hydrophilic modifier is prepared by the following steps:

[0043] Step B1: Sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate are mixed, heated to 150°C, maintained for 10 min, and then heated to 180°C and stirred for 2 h to obtain sulfonate monomers. The ratio of sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate is 0.3 mol: 0.72 mol: 0.03 g.

[0044] Step B2: Mix the sulfonate monomer obtained in step B1, polyethylene glycol, and antimony trioxide, heat to 250°C, seal the device and evacuate it for 20 minutes, then react for 30 minutes, remove the device, and obtain the hydrophilic modifier. The ratio of polyethylene glycol, sodium dimethyl isophthalate-5-sulfonate from step B1, and antimony trioxide is 0.12 mol: 0.3 mol: 0.02 g.

[0045] Example 2: The modified reinforcing agent was prepared by the following steps:

[0046] Step A1: Add 3-glycidoxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran to the polymerization tube and mix them. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted in an oil bath at 70°C for 20 hours to obtain the intermediate product 1,3-glycidoxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran in a ratio of 4 mmol:4 mmol:8 mL.

[0047] Step A2: Mix CNC, anhydrous ethanol, and deionized water, sonicate for 10 min, heat to 40°C, add intermediate product 1 solution dropwise, stir for 10 h, then centrifuge, wash, vacuum dry at 50°C for 2 h, and then dry in an oven at 110°C for 2 h to promote silane self-crosslinking, to obtain intermediate product 2. The volume ratio of CNC, anhydrous ethanol, deionized water, and intermediate product 1 solution is 0.1 g: 25 mL: 6.25 mL: 6 mL. Intermediate product 1 solution is prepared by mixing intermediate product 1 and anhydrous ethanol at a volume ratio of 3 mmol: 6 mL.

[0048] Step A3: Mix lauric acid, intermediate product 2 obtained in step A2, sodium bisulfate, and toluene. Heat the mixture in an oil bath to 120°C and reflux until anhydrous, then separate the mixture. Monitor the reaction using TLC. Cool to room temperature, add deionized water, stir for 15 min, allow to stand, separate, add 0.5 wt% sodium carbonate solution, stir for 15 min, allow to stand for layering, wash with water, and concentrate under vacuum to obtain the modified reinforcing agent. The ratio of lauric acid, intermediate product 1 from step A2, sodium bisulfate, toluene, deionized water, and sodium carbonate solution is 4 mol: 2.6 mmol: 1.25 mol: 7 mL: 4 mL: 4 mL.

[0049] The hydrophilic modifier is prepared by the following steps:

[0050] Step B1: Sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate are mixed, heated to 150°C, maintained for 10 min, and then heated to 180°C and stirred for 2 h to obtain sulfonate monomers. The ratio of sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate is 0.4 mol: 0.96 mol: 0.035 g.

[0051] Step B2: Mix the sulfonate monomer obtained in step B1, polyethylene glycol, and antimony trioxide, heat to 250°C, seal the device and evacuate it for 20 minutes, then react for 30 minutes, remove the device, and obtain the hydrophilic modifier. The ratio of polyethylene glycol, sodium dimethyl isophthalate-5-sulfonate from step B1, and antimony trioxide is 0.16 mol: 0.4 mol: 0.025 g.

[0052] Example 3: The modified reinforcing agent was prepared by the following steps:

[0053] Step A1: Add 3-glycidyloxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran to the polymerization tube and mix them. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted in an oil bath at 70°C for 20 hours to obtain the intermediate product 1,3-glycidyloxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran in a ratio of 5 mmol:5 mmol:10 mL.

[0054] Step A2: Mix CNC, anhydrous ethanol, and deionized water, sonicate for 10 min, heat to 40°C, add intermediate product 1 solution dropwise, stir for 10 h, then centrifuge, wash, vacuum dry at 50°C for 2 h, and then dry in an oven at 110°C for 2 h to promote silane self-crosslinking, to obtain intermediate product 2. The ratio of CNC, anhydrous ethanol, deionized water, and intermediate product 1 solution is 0.1 g: 30 mL: 7.5 mL: 8 mL. Intermediate product 1 solution is prepared by mixing intermediate product 1 and anhydrous ethanol at a ratio of 4 mmol: 8 mL.

[0055] Step A3: Mix lauric acid, intermediate product 2 obtained in step A2, sodium bisulfate, and toluene. Heat the mixture in an oil bath to 120°C, reflux until anhydrous, then separate the mixture. Monitor the reaction using TLC. Cool to room temperature, add deionized water, stir for 15 min, allow to stand, separate, add 0.5 wt% sodium carbonate solution, stir for 15 min, allow to stand for layering, wash with water, and concentrate under vacuum to obtain the modified reinforcing agent. The ratio of lauric acid, intermediate product 1 from step A2, sodium bisulfate, toluene, deionized water, and sodium carbonate solution is 6 mol: 3.9 mmol: 2 mol: 10 mL: 5 mL: 5 mL.

[0056] The hydrophilic modifier is prepared by the following steps:

[0057] Step B1: Sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate are mixed, heated to 150°C, maintained for 10 min, and then heated to 180°C and stirred for 2 h to obtain sulfonate monomers. The ratio of sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate is 0.5 mol: 1.2 mol: 0.04 g.

[0058] Step B2: Mix the sulfonate monomer obtained in step B1, polyethylene glycol, and antimony trioxide, heat to 250°C, seal the device and evacuate it for 20 minutes, then react for 30 minutes, remove the device, and obtain the hydrophilic modifier. The ratio of polyethylene glycol, sodium dimethyl isophthalate-5-sulfonate from step B1, and antimony trioxide is 0.2 mol: 0.5 mol: 0.03 g.

[0059] Example 4: A method for preparing a high tear-resistant nylon-polyester bilayer composite fiber, comprising the following steps:

[0060] The skin material comprises the following raw materials in parts by weight: 80 parts of polyamide 6 chips, 2 parts of the modified reinforcing agent prepared in Example 1, 0.1 parts of antioxidant 1098, and 0.1 parts of zinc stearate;

[0061] The core material comprises the following raw materials in parts by weight: 100 parts polyester chips, 5 parts hydrophilic modifier prepared in Example 1, and 0.5 parts trimethylolpropane trimethacrylate.

[0062] The core material is covered by a skin layer material, with 70 parts by weight of the core layer material and 40 parts by weight of the skin layer material.

[0063] Step S1: Weigh the raw materials according to the weight parts, add polyamide 6 chips, the modified reinforcing agent prepared in Example 1, antioxidant 1098 and zinc stearate to a high-speed mixer in sequence and mix and stir at 600 rpm for 10 min. Then extrude and granulate through a twin-screw extruder at an extrusion temperature of 230℃ to obtain the skin material.

[0064] Step S2: Mix polyester chips, trimethylolpropane trimethacrylate and the hydrophilic modifier prepared in Example 1, stir in a mixer for 20 minutes, and granulate by extrusion through a twin-screw extruder at an extrusion temperature of 220°C to obtain the core material.

[0065] Step S3: Dry the core material and the sheath material at 70°C until the moisture content is below 50 ppm; feed the dried core material and sheath material into two spinning systems respectively, melt them, filter them, and then input them into the core-sheath composite spinning assembly to obtain a high tear-resistant nylon-polyester bilayer composite fiber material. The spinning process is as follows: melt spinning, side-blowing cooling, oiling, winding, stretching, heat setting, and cutting. The spinning process parameters are: spinning speed 3500 m / min, side-blowing temperature 15°C, cooling air relative humidity 75%, side-blowing speed 0.4 m / min, stretching ratio 1.4, heat setting temperature 100°C, the number of spinnerets on the spinneret used for spinning is 36 holes, the maximum temperature of the extruder is controlled at 220°C, and the speed of the extruder main unit is 500 r / min.

[0066] Example 5: A method for preparing a high tear-resistant nylon-polyester bilayer composite fiber, comprising the following steps:

[0067] The skin material comprises the following raw materials in parts by weight: 90 parts of polyamide 6 chips, 4 parts of the modified reinforcing agent prepared in Example 2, 0.3 parts of antioxidant 1098, and 0.2 parts of zinc stearate;

[0068] The core material comprises the following raw materials in parts by weight: 100 parts polyester chips, 10 parts hydrophilic modifier prepared in Example 2, and 1 part trimethylolpropane trimethacrylate.

[0069] The core material is covered by a skin layer material, with 50 parts by weight of the core layer material and 70 parts by weight of the skin layer material.

[0070] Step S1: Weigh the raw materials according to the weight parts, add polyamide 6 chips, the modified reinforcing agent prepared in Example 2, antioxidant 1098 and zinc stearate to a high-speed mixer in sequence, mix and stir at 700 rpm for 13 min, and then extrude and granulate through a twin-screw extruder at an extrusion temperature of 235℃ to obtain the skin material.

[0071] Step S2: Mix polyester chips, trimethylolpropane trimethacrylate and the hydrophilic modifier prepared in Example 2, stir in a mixer for 25 minutes, and extrude and granulate it through a twin-screw extruder at an extrusion temperature of 260°C to obtain the core material.

[0072] Step S3: Dry the core material and the sheath material at 80℃ until the moisture content is below 50ppm; feed the dried core material and sheath material into two spinning systems respectively, melt them, filter them, and then input them into the core-sheath composite spinning assembly to obtain a high tear-resistant nylon-polyester bilayer composite fiber material. The spinning process is as follows: melt spinning, side-blowing cooling, oiling, winding, stretching, heat setting, and cutting. The spinning process parameters are: spinning speed 3700m / min, side-blowing temperature 15℃, cooling air relative humidity 75%, side-blowing speed 0.4m / min, stretching ratio 1.4, heat setting temperature 100℃, the number of spinnerets on the spinneret used for spinning is 36 holes, the maximum temperature of the extruder is controlled at 220℃, and the speed of the extruder main unit is 500r / min.

[0073] Example 6: A method for preparing a high tear-resistant nylon-polyester bilayer composite fiber, comprising the following steps:

[0074] The skin material comprises the following raw materials in parts by weight: 100 parts of polyamide 6 chips, 5 parts of the modified reinforcing agent prepared in Example 3, 0.6 parts of antioxidant 1098, and 0.4 parts of zinc stearate;

[0075] The core material comprises the following raw materials in parts by weight: 100 parts polyester chips, 15 parts hydrophilic modifier prepared in Example 3, and 2 parts trimethylolpropane trimethacrylate.

[0076] The core material is covered by a skin layer material, with 40 parts by weight of the core layer material and 40 parts by weight of the skin layer material.

[0077] Step S1: Weigh the raw materials according to the weight parts, add polyamide 6 chips, the modified reinforcing agent prepared in Example 3, antioxidant 1098 and zinc stearate to a high-speed mixer in sequence, mix and stir at 800 rpm for 15 min, and then extrude and granulate through a twin-screw extruder at an extrusion temperature of 240℃ to obtain the skin material.

[0078] Step S2: Mix polyester chips, trimethylolpropane trimethacrylate and the hydrophilic modifier prepared in Example 3, stir in a mixer for 30 minutes, and extrude and granulate it through a twin-screw extruder at an extrusion temperature of 280°C to obtain the core material.

[0079] Step S3: Dry the core material and the sheath material at 90℃ until the moisture content is below 50ppm; feed the dried core material and sheath material into two spinning systems respectively, melt them, filter them, and then input them into the core-sheath composite spinning assembly to obtain a high tear-resistant nylon-polyester bilayer composite fiber material. The spinning process is as follows: melt spinning, side-blowing cooling, oiling, winding, stretching, heat setting, and cutting. The spinning process parameters are: spinning speed 4000m / min, side-blowing temperature 15℃, cooling air relative humidity 75%, side-blowing speed 0.4m / min, stretching ratio 1.4, heat setting temperature 100℃, the number of spinnerets on the spinneret used for spinning is 36 holes, the maximum temperature of the extruder is controlled at 220℃, and the speed of the extruder main unit is 500r / min.

[0080] Comparative Example 1: This comparative example is a nylon-polyester bilayer composite fiber. The difference between this example and Example 6 is that CNC is used instead of the modified reinforcing agent prepared in Example 3. All other aspects are the same.

[0081] Comparative Example 2: This comparative example is a nylon-polyester bilayer composite fiber. The difference between this example and Example 6 is that polyether F-6 is used instead of the hydrophilic modifier prepared in Example 3. All other aspects are the same.

[0082] Comparative Example 3: This comparative example is a nylon-polyester bilayer composite fiber. The difference between it and Example 6 is that CNC is used instead of the modified reinforcing agent prepared in Example 3, and polyether F-6 is used instead of the hydrophilic modifier prepared in Example 3. All other aspects are the same.

[0083] The composite fibers prepared in Examples 4-6 and Comparative Examples 1-3 were subjected to performance tests:

[0084] Tear resistance: Tested according to GB / T3917.2-2009;

[0085] Moisture permeability: Tested according to GB / T12704.1-2009 "Textiles - Test methods for moisture permeability of fabrics - Part 1: Moisture absorption method";

[0086] The test results are shown in Table 1:

[0087] Table 1: Performance Test Results

[0088]

[0089] As can be seen from Table 1, the bilayer composite fiber prepared by this invention has excellent tear resistance and moisture absorption properties. The tear resistance of the composite fibers obtained in the examples all reached above 11.8 N, and the moisture permeability reached 6878 g / m³. 2• More than 24 hours. Comparative Example 6 and Comparative Example 1 show that the modified reinforcing agent prepared in this invention improves the tear resistance of the composite fiber; comparative Example 6 and Comparative Example 2 show that the hydrophilic modifier prepared in this invention improves the moisture permeability of the composite fiber. This demonstrates that the bilayer composite fiber of this invention possesses excellent tear resistance and moisture absorption.

[0090] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. A high tear-resistant nylon-polyester bilayer composite fiber, characterized in that, The composite fiber is composed of a sheath material and a core material; the sheath material comprises the following raw materials in parts by weight: 80-100 parts of polyamide 6 chips, 2-5 parts of modified reinforcing agent, 0.1-0.6 parts of antioxidant 1098, and 0.1-0.4 parts of zinc stearate; The core material comprises the following raw materials in parts by weight: 100 parts polyester chips, 5-15 parts hydrophilic modifier, and 0.5-2 parts crosslinking agent; The modified reinforcing agent is prepared by the following steps: Step A1: Add 3-glycidyl etheroxypropyltrimethoxysilane, 9-anthracarboxylic acid and tetrahydrofuran to the polymerization tube and mix them. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted in an oil bath at 70°C for 20 hours to obtain intermediate product 1. Step A2: Mix CNC, anhydrous ethanol and deionized water, sonicate for 10 min, heat to 40°C, add intermediate product 1 solution dropwise, stir for 10 h, then centrifuge, wash, vacuum dry at 50°C for 2 h, and then dry in an oven at 110°C for 2 h to promote silane self-crosslinking, to obtain intermediate product 2. Step A3: Mix lauric acid, intermediate product 2 obtained in step A2, sodium bisulfate and toluene, heat in an oil bath to 120°C, reflux until anhydrous, then separate, monitor with TLC, cool to room temperature, add deionized water, stir for 15 min, let stand, separate, add 0.5 wt% sodium carbonate solution, stir for 15 min, let stand to separate, wash with water, vacuum concentrate to obtain the modified reinforcing agent.

2. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 1, characterized in that, In step A1, the ratio of 3-glycidyl etheroxypropyltrimethoxysilane, 9-anthracarboxylic acid, and tetrahydrofuran is 3-5 mmol: 3-5 mmol: 6-10 mL.

3. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 1, characterized in that, In step A2, the ratio of CNC, anhydrous ethanol, deionized water and intermediate product 1 solution is 0.1g:20-30mL:5-7.5mL:4-8mL. Intermediate product 1 solution is prepared by mixing intermediate product 1 and anhydrous ethanol in a ratio of 2-4mmol:4-8mL.

4. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 1, characterized in that, The ratio of lauric acid, intermediate product 1 from step A2, sodium bisulfate, toluene, deionized water, and sodium carbonate solution used in step A3 is 2-6 mol: 1.3-3.9 mmol: 0.5-2 mol: 4-10 mL: 3-5 mL: 3-5 mL.

5. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 1, characterized in that, The outer layer material covers the core layer material, with 40-70 parts by weight of the core layer material and 40-70 parts by weight of the outer layer material. The crosslinking agent is trimethylolpropane trimethacrylate.

6. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 1, characterized in that, The hydrophilic modifier is prepared by the following steps: Step B1: Sodium dimethyl isophthalate-5-sulfonate, ethylene glycol and zinc acetate are mixed, heated to 150°C, maintained for 10 min, and then heated to 180°C and stirred for 2 h to obtain the sulfonate monomer. Step B2: Mix the sulfonate monomer, polyethylene glycol and antimony trioxide obtained in step B1, heat to 250°C, seal the device and evacuate it for 20 minutes, then react for 30 minutes, remove the device, and obtain the hydrophilic modifier.

7. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 6, characterized in that, In step B1, the ratio of sodium dimethyl phthalate-5-sulfonate, ethylene glycol, and zinc acetate is 0.3-0.5 mol: 0.72-1.2 mol: 0.03-0.04 g.

8. The high tear-resistant nylon-polyester bilayer composite fiber according to claim 6, characterized in that, In step B2, the ratio of polyethylene glycol, sodium dimethyl isophthalate-5-sulfonate, and antimony trioxide in step B1 is 0.12-0.2 mol: 0.3-0.5 mol: 0.02-0.03 g.

9. A method for preparing the high tear-resistant nylon-polyester bilayer composite fiber according to any one of claims 1-8, characterized in that, The high tear-resistant nylon-polyester bilayer composite fiber is prepared by the following steps: Step S1: Weigh the raw materials according to the weight parts, add polyamide 6 chips, modifier, antioxidant 1098 and zinc stearate to a high-speed mixer in sequence and mix at a speed of 600-800 rpm for 10-15 minutes. Then extrude and granulate through a twin-screw extruder at an extrusion temperature of 230-240℃ to obtain the skin material. Step S2: Mix polyester chips, crosslinking agent and hydrophilic modifier, put them into a mixer and stir for 20-30 minutes, then extrude and granulate them through a twin-screw extruder at an extrusion temperature of 220-280℃ to obtain the core material; Step S3: Dry the core material and the sheath material at 70-90℃ until the moisture content is below 50ppm; feed the dried core material and sheath material into two spinning systems respectively, melt them, filter them, and then input them into the core-sheath composite spinning assembly to obtain a high tear-resistant nylon-polyester bilayer composite fiber material.

10. The method for preparing high tear-resistant nylon-polyester bilayer composite fiber according to claim 9, characterized in that, The spinning process in step S3 is as follows: melt spinning, side blowing cooling, oiling, winding, stretching, heat setting, and cutting. The spinning process parameters are: spinning speed 3500-4000 m / min, side blowing temperature 15℃, cooling air relative humidity 75%, side blowing speed 0.4 m / min, stretching ratio 1.4, heat setting temperature 100℃, the number of spinnerets on the spinneret used for spinning is 36, the maximum temperature of the extruder is controlled at 220℃, and the speed of the extruder main unit is 500 r / min.

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