ES composite fiber and preparation method thereof

Abstract

The present invention discloses an ES composite fiber and a preparation method thereof. The ES composite fiber is a composite fiber with a core-skin structure having a PE resin as a skin layer and a stacked co-extruded PP / PET resin as a core layer. The PP / PET resin is prepared by micro-nano stacking co-extrusion technology from PP and PET, and has multiple PP layers and PET layers arranged alternately in stacks. The core layer and the skin layer resins are subjected to melt composite spinning, pre-spinning oiling, winding and barreling, drawing, drying and shaping, post-spinning oiling and segmenting to obtain the ES composite fiber. The ES composite fiber provided by the present invention combines the advantages of PP / PE and PET / PE composite fibers, has high strength and heat sealing stability, and due to the different thermal shrinkage rates of the core layer PP and PET, the spiral curling of the fiber is promoted during cooling and shaping, making it more fluffy and soft, and having good moisture absorption and flow conduction properties.

Description

Technical Field

[0001] This invention belongs to the field of functional composite fibers, specifically relating to an ES composite fiber and its preparation method. Background Technology

[0002] ES fiber is a sheath-core composite fiber composed of two different polymer materials (PP / PE or PET / PE), possessing characteristics such as good softness, low melting point of the outer layer, high melting point of the inner layer, and high strength. After reprocessing and heat treatment, part of the sheath layer melts and bonds, while the remaining fibers retain their fibrous state. This maintains the fiber's fluffy and soft characteristics without damaging its structure, resulting in high strength and making it a primary raw material for mid-to-high-end hygiene products. Currently, the three most commonly used raw materials for producing ES fiber are PE, PP, and PET, with PP and PET, which have higher melting points, used as the core layer, and PE, which has a lower melting point, used as the sheath layer. PP / PE composite nonwoven fabrics have excellent heat-sealing properties, a soft feel, and good water repellency; PET / PE sheath-core composite fibers have high strength, good fluffiness, and high elastic recovery rate, exhibiting high strength and excellent waterproof performance. With the continuous improvement of people's living standards, the market's requirements for the quality of hygiene products are also constantly increasing. The development of ES fiber must further adapt to market demands, such as lightweight, skin-friendly softness and elasticity, and better moisture absorption, wicking, and quick-drying functions.

[0003] Micro / nano lamination technology, also known as multilayer co-extrusion technology, is a novel melt processing technology. It involves connecting multiple laminators in series after traditional extrusion operations, enabling the synthesis of multilayer polymer composites ranging from nanometer to micrometer scales in the molten state. Within the laminator, the polymer melt undergoes splitting, diffusion, and stacking. During this process, not only are the melt channels elongated, but the polymer melt is also subjected to continuous shear and tensile forces. These force fields help improve the distribution and morphology of the dispersed phase in the matrix. Furthermore, the convergent stretching effect within the laminator forms polymer microfibers at the interlayer interfaces, resulting in advantages such as good two-phase compatibility, uniform dispersion, and significant and controllable reinforcing effects. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of ES fibers in terms of performance, and to provide an ES composite fiber with higher strength and heat-sealing stability, greater fluffiness and softness, and better moisture absorption, wicking and quick-drying functions, as well as its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An ES composite fiber is a coaxial core-sheath structure composite fiber with PE resin as the sheath and PP / PET resin co-extruded in layers as the core, wherein the weight ratio of PE resin to PP / PET resin co-extruded in layers is 70:30 to 55:45.

[0007] The laminated co-extruded PP / PET resin is composed of 2 n It consists of alternating layers of PP and PET, n = 2 to 32, wherein the weight ratio of PP to PET is 20:80 to 80:20.

[0008] The melt flow rate of the PE resin is 15-35 g / 10 min, and the melt flow rate of the laminated co-extruded PP / PET resin is 15-45 g / 10 min.

[0009] The method for preparing the co-extruded PP / PET resin includes the following steps: PP resin and PET resin are respectively fed into two extruders and passed through a micro-nano co-extruded device consisting of a stack distributor, a flaring die, a flow divider, and a cutting mechanism. The two phases are continuously divided and superimposed in the stack distributor. Under the action of a convergent-stretching composite flow field, an alternating multilayer micro-layer structure is formed, and the co-extruded PP / PET resin is obtained by melt extrusion. The stack distributor consists of m stack units connected in series. The composite melt is divided into two equal parts along the width direction at the inlet of the stack unit. Each equal part continues to flow forward along the orientation die and rotates 90° while widening by 2 times and reducing its thickness to 1 / 2 times. It then merges at the outlet and enters the next stack unit. The number of stack units m = 1 to 5.

[0010] The method for preparing the ES fiber includes the following steps:

[0011] S1. First, PE resin is fed into a twin-screw extruder to melt and form melt A. Then, melt A is fed into the spinning box via a metering pump. The temperature of melt A before entering the spinning box is controlled at 235-260℃.

[0012] S2. The laminated co-extruded PP / PET resin is fed into the twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 250-280℃.

[0013] S3. Melt A and melt B simultaneously enter the spinning box and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section, and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole, and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, they form a core-sheath composite fiber.

[0014] S4. Finally, the fibers are cooled, pre-spinned and oiled, wound and dropped into the drum, drawn, dried and set, post-spinned and oiled, and cut into sections to obtain ES composite fibers.

[0015] In step S3, the temperature of the spinning box is controlled at 260-285°C.

[0016] In step S4, the cooling conditions are: side-blowing wind speed of 0.5 to 1.5 m / s, wind temperature of 20 to 30°C, wind humidity of 70% to 80%, and wind pressure of 600 to 950 Pa.

[0017] In step S4, the amount of oil applied during the pre-spinning process is 1.2% to 2.0%, and the winding speed during the winding and dropping process is 550 to 850 m / min.

[0018] This invention utilizes micro-nano lamination technology to composite and spin PP and PET together, which can achieve good compatibility and mutual compensation of physical properties. Furthermore, PP / PET composite fibers are melt-spun with PE to fully combine the various advantages of PP and PET fibers. This not only has good heat-sealing stability and strength, but is also more fluffy and soft, making it particularly suitable for the production of sanitary materials, thermal insulation fillers, filter materials and other products.

[0019] The present invention has the following beneficial effects:

[0020] 1. The uniform distribution of PP and PET resins is achieved through a micro-nano stacked co-extrusion device. By utilizing the strong shear and tensile flow field in the stacker, microfibers of PP and PET are obtained at the interlayer interface. On the one hand, it combines the advantages of PP / PE and PET / PE composite fibers, which have high moisture absorption and heat-sealing stability; on the other hand, it also improves the strength of the composite resin.

[0021] 2. Due to the different heat shrinkage rates of PP and PET, the fibers will spiral curl during cooling and setting, making them more fluffy, soft, and with good flowability.

[0022] 3. The process of this invention is simple, easy to operate and control, can be continuously produced, has high production efficiency and low production cost. Furthermore, by adjusting the ratio of PP and PET in the core layer, the performance of ES fiber can be controlled to a certain extent, which has strong industrialization capability and broad market prospects. Detailed Implementation

[0023] The following examples are intended to enable those skilled in the art to better understand the present invention, but are not intended to limit the invention in any way.

[0024] Example 1

[0025] 1. Preparation of laminated co-extruded PP / PET resin:

[0026] PP resin and PET resin are fed into two extruders at a weight ratio of 80:20. Through a micro-nano stacked extrusion device composed of three series stacked units, the two phases are continuously divided and superimposed in the layer distributor. Under the action of the convergent-stretch composite flow field, an alternating 8-layer micro-layer structure is formed, and the stacked co-extruded PP / PET resin is obtained by melt extrusion.

[0027] 2. Preparation of ES composite fibers:

[0028] S1. 70 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A. Melt A is then fed into the spinning box via a metering pump. The temperature of melt A before entering the spinning box is controlled at 245°C.

[0029] S2. 30 parts by weight of laminated co-extruded PP / PET resin are fed into a twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 275℃.

[0030] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 265°C) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0031] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0032] The cooling conditions are as follows: the side-blowing wind speed is 1 m / s, the wind temperature is 30℃, the wind humidity is 80%, and the wind pressure is 800 Pa; the oiling amount in the pre-spinning oiling is 1.2%, and the winding speed of the winding and falling into the drum is 700 m / min.

[0033] Example 2

[0034] 1. Preparation of laminated co-extruded PP / PET resin:

[0035] PP resin and PET resin are fed into two extruders at a weight ratio of 80:20. Through a micro-nano stacked extrusion device composed of three series stacked units, the two phases are continuously divided and superimposed in the layer distributor. Under the action of the convergent-stretch composite flow field, an alternating 8-layer micro-layer structure is formed, and the stacked co-extruded PP / PET resin is obtained by melt extrusion.

[0036] 2. Preparation of ES composite fibers:

[0037] S1. 60 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A, which is then pumped into the spinning box. The temperature of melt A before entering the spinning box is controlled at 255℃.

[0038] S2. 40 parts by weight of laminated co-extruded PP / PET resin are fed into a twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 270℃.

[0039] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 270℃) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0040] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0041] The cooling conditions are as follows: the side-blowing wind speed is 1 m / s, the wind temperature is 30℃, the wind humidity is 75%, and the wind pressure is 800 Pa; the oiling amount in the pre-spinning oiling is 1.2%, and the winding speed in the winding and dropping drum is 700 m / min.

[0042] Example 3

[0043] 1. Preparation of laminated co-extruded PP / PET resin:

[0044] PP resin and PET resin are fed into two extruders at a weight ratio of 80:20. Through a micro-nano stacked extrusion device composed of three series stacked units, the two phases are continuously divided and superimposed in the layer distributor. Under the action of the convergent-stretch composite flow field, an alternating 8-layer micro-layer structure is formed, and the stacked co-extruded PP / PET resin is obtained by melt extrusion.

[0045] 2. Preparation of ES composite fibers:

[0046] S1. 55 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A, which is then pumped into the spinning box. The temperature of melt A before entering the spinning box is controlled at 255°C.

[0047] S2. 45 parts by weight of laminated co-extruded PP / PET resin are fed into a twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 270℃.

[0048] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 270℃) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0049] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0050] The cooling conditions are as follows: side-blowing wind speed is 0.8 m / s, wind temperature is 30℃, wind humidity is 70%, and wind pressure is 800 Pa; the oiling amount during the pre-spinning process is 1.2%, and the winding speed during the winding and dropping process is 700 m / min.

[0051] Example 4

[0052] 1. Preparation of laminated co-extruded PP / PET resin:

[0053] PP resin and PET resin are fed into two extruders at a weight ratio of 50:50. Through a micro-nano stacked extrusion device composed of three series stacked units, the two phases are continuously divided and superimposed in the layer distributor. Under the action of the convergent-stretch composite flow field, an alternating 8-layer micro-layer structure is formed, and the stacked co-extruded PP / PET resin is obtained by melt extrusion.

[0054] 2. Preparation of ES composite fibers:

[0055] S1. 60 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A, which is then pumped into the spinning box. The temperature of melt A before entering the spinning box is controlled at 255℃.

[0056] S2. 40 parts by weight of laminated co-extruded PP / PET resin are fed into a twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 270℃.

[0057] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 265°C) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0058] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0059] The cooling conditions are as follows: the side-blowing wind speed is 1 m / s, the wind temperature is 30℃, the wind humidity is 80%, and the wind pressure is 800 Pa; the oiling amount in the pre-spinning oiling is 1.2%, and the winding speed of the winding and falling into the drum is 700 m / min.

[0060] Example 5

[0061] 1. Preparation of laminated co-extruded PP / PET resin:

[0062] PP resin and PET resin are fed into two extruders at a weight ratio of 20:80. Through a micro-nano stacked extrusion device composed of three series stacked units, the two phases are continuously divided and superimposed in the layer distributor. Under the action of the convergent-stretch composite flow field, an alternating 8-layer micro-layer structure is formed, and the stacked co-extruded PP / PET resin is obtained by melt extrusion.

[0063] 2. Preparation of ES composite fibers:

[0064] S1. 60 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A, which is then pumped into the spinning box. The temperature of melt A before entering the spinning box is controlled at 255℃.

[0065] S2. 40 parts by weight of laminated co-extruded PP / PET resin are fed into a twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 270℃.

[0066] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 265°C) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0067] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0068] The cooling conditions are as follows: the side-blowing wind speed is 1 m / s, the wind temperature is 30℃, the wind humidity is 80%, and the wind pressure is 800 Pa; the oiling amount in the pre-spinning oiling is 1.2%, and the winding speed of the winding and falling into the drum is 700 m / min.

[0069] Comparative Example 1

[0070] S1. 60 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A, which is then pumped into the spinning box. The temperature of melt A before entering the spinning box is controlled at 255℃.

[0071] S2. 40 parts by weight of PP resin are fed into the twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 270℃.

[0072] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 265°C) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0073] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0074] The cooling conditions are as follows: the side-blowing wind speed is 1 m / s, the wind temperature is 30℃, the wind humidity is 80%, and the wind pressure is 800 Pa; the oiling amount in the pre-spinning oiling is 1.2%, and the winding speed of the winding and falling into the drum is 700 m / min.

[0075] Comparative Example 2

[0076] S1. 60 parts by weight of PE resin are fed into a twin-screw extruder to melt and form melt A, which is then pumped into the spinning box. The temperature of melt A before entering the spinning box is controlled at 255℃.

[0077] S2. 40 parts by weight of PET resin are fed into a twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 270°C.

[0078] S3. Melt A and melt B simultaneously enter the spinning box (the temperature of the spinning box is controlled at 265°C) and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, a core-sheath composite fiber is formed.

[0079] S4. Finally, after cooling, pre-spinning oiling, winding and dropping into the drum, stretching, drying and setting, post-spinning oiling and cutting, ES composite fiber is obtained.

[0080] The cooling conditions are as follows: the side-blowing wind speed is 1 m / s, the wind temperature is 30℃, the wind humidity is 80%, and the wind pressure is 800 Pa; the oiling amount in the pre-spinning oiling is 1.2%, and the winding speed of the winding and falling into the drum is 700 m / min.

[0081] Table 1 Comparison of ES Composite Fiber Properties

[0082]

[0083] As can be seen from the data in Table 1, compared with the ES fibers prepared by layered co-extrusion of PP / PET resin as core material in Comparative Examples 1 and 2, which respectively use pure PP and PET as core material, the ES composite fibers prepared by the present invention in Examples 1-5 can achieve a finer fineness and a higher number of crimps per unit length, making the fabric more fluffy and soft. At the same time, its richer three-dimensional helical structure also provides better elasticity and better moisture absorption and quick-drying performance.

[0084] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art should understand that the specific descriptions above are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

Claims

1. An ES composite fiber, characterized in that, It is a core-sheath composite fiber with PE resin as the sheath and co-extruded PP / PET resin as the core. The weight ratio of PE resin to co-extruded PP / PET resin is 70:30 to 55:

45. The co-extruded PP / PET resin is composed of 2... n It consists of alternating layers of PP and PET, n=2~32, wherein the weight ratio of PP to PET is 20:80 to 80:20; The method for preparing the co-extruded PP / PET resin includes the following steps: PP resin and PET resin are respectively fed into two extruders and passed through a micro-nano co-extruded device consisting of a stack distributor, a flaring die, a flow divider, and a cutting mechanism. The two phases are continuously divided and superimposed in the stack distributor. Under the action of a convergent-stretching composite flow field, an alternating multilayer micro-layer structure is formed, and the co-extruded PP / PET resin is obtained by melt extrusion. The stack distributor consists of m stack units connected in series. The composite melt is divided into two equal parts along the width direction at the inlet of the stack unit. Each equal part continues to flow forward along the orientation die and rotates 90° while widening by 2 times and reducing its thickness to 1 / 2 times. It then merges at the outlet and enters the next stack unit. The number of stack units m = 1~5.

2. The ES composite fiber according to claim 1, characterized in that, The melt flow rate of the PE resin is 15-35 g / 10 min, and the melt flow rate of the laminated co-extruded PP / PET resin is 15-45 g / 10 min.

3. The method for preparing an ES composite fiber as described in claim 1 or 2, characterized in that, Includes the following steps: S1. First, PE resin is fed into a twin-screw extruder to melt and form melt A. Then, melt A is fed into the spinning box via a metering pump. The temperature of melt A before entering the spinning box is controlled at 235-260℃. S2. The laminated co-extruded PP / PET resin is fed into the twin-screw extruder through a masterbatch injector to melt and form melt B. Melt B is then fed into the spinning box through a metering pump. The temperature of melt B before entering the spinning box is controlled at 250-280℃. S3. Melt A and melt B simultaneously enter the spinning box and are ejected from the spinneret. The spinneret is provided with a number of spinneret holes. Each spinneret hole includes a cylindrical guide hole section, a conical guide hole section, and a spinneret micro-hole section arranged sequentially from top to bottom. The spinneret micro-hole section has a coaxial double-layer structure. After melt A and melt B enter the spinning box at the same time, melt A flows into the outer layer of the spinneret hole, and melt B flows into the inner layer of the spinneret hole. Finally, after being ejected through the spinneret hole, they form a core-sheath composite fiber. S4. Finally, the fibers are cooled, pre-spinned and oiled, wound and dropped into the drum, drawn, dried and set, post-spinned and oiled, and cut into sections to obtain ES composite fibers.

4. The method for preparing ES composite fiber according to claim 3, characterized in that, In step S3, the temperature of the spinning box is controlled at 260-285°C.

5. The method for preparing ES composite fiber according to claim 3, characterized in that, In step S4, the cooling conditions are: side-blowing wind speed of 0.5 to 1.5 m / s, wind temperature of 20 to 30°C, wind humidity of 70% to 80%, and wind pressure of 600 to 950 Pa.

6. The method for preparing ES composite fiber according to claim 3, characterized in that, In step S4, the amount of oil applied during the pre-spinning process is 1.2% to 2.0%, and the winding speed during the winding and dropping process is 550 to 850 m / min.

Images