Preparation method of elastic fiber

Abstract

The invention provides the preparation method of the elastic fiber, and according to the preparation method of the elastic fiber, the same fiber forming polymer melt is adopted, and the juxtaposed elastic fiber produced only needs one melting device (namely, one extruder) in a manner of shunting, spraying out of spinneret orifices with different pore diameters, collecting and bonding. According to the mode, the equipment configuration is simplified, and compared with the complex configuration of a plurality of melting devices in the traditional process, the equipment investment is obviously reduced. The elastic fibers are made of the same material and are convenient to recycle and regenerate.

Description

Technical Field

[0001] The invention belongs to the technical field of fiber preparation, and in particular relates to a method for preparing elastic fiber. Background Art

[0002] Elastic fibers can achieve a wide range of elastic recovery and are made into fabrics that are soft and close to the skin. There are many ways to achieve fiber elasticity. One is intrinsic elasticity, that is, the molecular structure of the fiber material. The molecular chain itself has high resilience, such as spandex. Another is that the fiber has a three-dimensional curled structure, which has a physical rebound effect similar to a spring. In synthetic fibers, the three-dimensional curled structure can be obtained by false twisting straight yarns, or by compounding two materials with different shrinkage properties on a fiber in parallel, and then shrinking them under certain conditions, which will make the fiber appear naturally curled and have good elasticity. Using heterogeneous materials with large differences in shrinkage rates has better results. Parallel composite nylon elastic fibers themselves have good elasticity. In many applications, they do not need to be compounded with spandex. They have the advantages of good dyeing performance and good recycling.

[0003] At present, the technical scheme generally adopts two materials with different molecular structures, such as PET / PBT, PA6 / PA66, etc. to prepare elastic fibers by parallel compounding. There are also materials with the same molecular structure but different molecular weights, such as high-viscosity or low-viscosity PET or PA6. Commercial products include INVISTA's T400 and DuPont's T800.

[0004] Using raw materials of the same type or specification will make recycling easier, but the elastic effect is not good. The use of heterogeneous materials to prepare parallel elastic fibers has good elastic effect, but heterogeneous materials increase the difficulty of material recycling. The performance of the recycled materials is different from that of the single material, and the performance changes with different proportions. It cannot be stable and can only be downgraded for use. For chemical recycling, the monomer components of different materials are different, which increases the difficulty of separation and energy consumption. Using the same polymer material with different viscosities has a weaker elastic effect, and two sets of melting devices are still required, and the curling effect is not obvious. Therefore, it is necessary to develop a fiber that has good elastic effect and is easy to recycle. Summary of the invention

[0005] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention provides a method for preparing elastic fibers. The method for preparing elastic fibers of the present invention uses the same fiber-forming polymer melt to be ejected through spinnerets with different apertures and converged and bonded, and the elastic fibers produced only require one melting device (i.e., one extruder). This method simplifies the equipment configuration and significantly reduces the equipment investment compared to the complex configuration of multiple melting devices required in the traditional process.

[0006] The first aspect of the present invention provides a method for preparing elastic fibers, comprising dividing the same fiber-forming polymer melt into several parts, spraying them out through spinnerets with different apertures respectively and bonding them at the converging point.

[0007] A technical solution in the method for preparing elastic fiber of the present invention has at least the following beneficial effects:

[0008] The elastic fiber preparation method of the present invention uses the same fiber-forming polymer melt to be ejected through spinnerets with different apertures and then converged and bonded. The elastic fiber produced only requires one melting device (i.e., one extruder). This method simplifies the equipment configuration and significantly reduces the equipment investment compared to the complex configuration of multiple melting devices required in the traditional process.

[0009] The method for preparing elastic fibers of the present invention uses the same melt and realizes the production of parallel elastic fibers through a low-energy consumption melt direct spinning process in the process design. Therefore, compared with the traditional process of parallel compounding of different materials that requires high energy consumption, the present invention has lower energy consumption.

[0010] The method for preparing elastic fibers of the present invention produces parallel curly yarns, and the fibers themselves have a single component. By using fiber materials of the same single component (rather than composites of heterogeneous materials), the produced fibers not only have good elasticity, but also can show performance close to that of new materials during physical recycling. This allows the recycled materials to be better reused, meets environmental protection requirements, and reduces energy consumption and difficulty during the recycling process. In particular, during chemical recycling, since a single polymer material is used, the monomer components after depolymerization are also relatively single, thereby reducing the complexity of the separation process and improving the recycling efficiency. In addition, in most applications, it can be made into elastic fabrics alone without the need to be composited with other highly elastic fibers. The performance of the polymer material after physical recycling is close to that of new materials, and is suitable for recycling.

[0011] The present invention realizes the curling structure of the fiber by dividing the same fiber-forming polymer melt into several parts and using spinnerets with different apertures. This curling effect gives the fiber excellent elastic properties, so that it can be used alone in most applications without compounding other highly elastic materials (such as spandex). Therefore, the elastic fiber produced can independently exert good performance in fabric manufacturing, reducing the dependence on other high-cost composite fibers.

[0012] Since the same material is used and the performance is close to that of new material through physical recycling, the present invention can effectively maintain the stability of material performance during the recycling process, avoiding performance fluctuations caused by the parallel compounding of different materials. The stability of this material can not only meet different industrial needs, but also make the recycled fiber have better comprehensive performance when it is used again, further improving the sustainability of the material.

[0013] In the present invention, the same fiber-forming polymer melt is divided into several parts, which are ejected through spinnerets of different diameters and bonded at the converging point, so that the natural curl of the fiber can be effectively achieved and the fiber is endowed with excellent elasticity. Specifically:

[0014] When the fiber filaments are ejected from spinnerets of different diameters, they shrink to different degrees. The thinner fiber filaments shrink relatively quickly due to the smaller tension, while the thicker fiber filaments shrink slowly. This difference causes the fiber to naturally form a curled state after cooling. The natural curling structure of the fiber has good resilience like a spring, which enables the fiber to quickly return to its original shape under the action of external force, showing excellent elastic recovery ability.

[0015] The present invention adjusts the diameter difference of the spinneret holes to make the fiber curl naturally during the production process, without the need for false twisting or external chemical treatment in the traditional method. This not only simplifies the production process, but also avoids the negative impact of chemical treatment on fiber properties (such as uneven dyeing or degradation of material properties).

[0016] The three-dimensional curled structure of the fiber enables it to quickly return to its original shape after the external force is released, providing a strong elastic recovery force. This structure is similar to a spring, which can significantly improve the elasticity of the fiber, making it more elastic and comfortable in fabrics, especially in the field of clothing, providing a better wearing experience.

[0017] By adjusting the difference in spinneret hole diameter, the curling degree and elastic effect of the fiber can be adjusted according to different needs, which has greater production flexibility. This means that during the production process, the fiber structure can be precisely controlled according to specific fiber elasticity requirements, thereby meeting the application requirements of various elastic textiles, such as elastic sportswear, underwear fabrics, etc.

[0018] The naturally curled fibers not only increase elasticity, but also make the fabric more three-dimensional and improve the comfort of the textile. The curled structure allows the fiber to evenly distribute stress when stretched, avoiding deformation or breakage that may be caused by direct stretching of the fiber, and improving the durability and comfort of the fabric.

[0019] The same fiber material is used and the fiber curling is achieved through physical means (spinneret hole design), without the need to add other high-cost or difficult-to-recycle highly elastic materials (such as spandex). Therefore, the produced fiber has good recyclability and meets the sustainable development requirements of modern fiber products. During the recycling process, the fiber can easily restore its performance through physical or chemical methods, reducing the difficulty of material recycling.

[0020] Therefore, the fiber preparation method of the present invention imparts excellent elasticity to the fiber by natural curling, while avoiding complicated post-processing processes, which not only improves the elastic effect of the fiber, but also makes the production process simpler and more efficient, meeting the requirements of environmental protection and sustainable development. These advantages make the elastic fiber of the present invention have important market competitiveness in the production and application of elastic textiles.

[0021] According to some embodiments of the present invention, the fiber-forming polymer melt includes one of a polyamide melt and a polyester melt.

[0022] According to some embodiments of the present invention, the polyamide melt includes polyamide 6, polyamide 66, polyamide 12, polyamide 56, polyamide 6 / 66, polyamide 66 / 6, polyamide 56 / 66 or polyamide 66 / 56.

[0023] Polyamide 6 / 66 refers to the copolymer of polyamide 6 and 66, which is the same material, not polyamide 6 and polyamide 66.

[0024] The difference between polyamide 6 / 66 and polyamide 66 / 6 is that in polyamide 6 / 66, the content of polyamide 6 is greater than that of polyamide 66. Similarly, in polyamide 66 / 6, the content of polyamide 66 is greater.

[0025] According to some embodiments of the invention, the number of the plurality of parts is 2.

[0026] According to some embodiments of the present invention, the spinneret hole comprises a spinneret hole A and a spinneret hole B, and the diameter of the spinneret hole A is greater than the diameter of the spinneret hole B.

[0027] According to some embodiments of the present invention, the spinneret includes spinneret A and spinneret B, and the equivalent diameter of spinneret A is greater than the equivalent diameter of spinneret B.

[0028] According to some embodiments of the present invention, the ratio of the diameter of the spinneret hole A to the diameter of the spinneret hole B is 1.5 to 5:1.

[0029] According to some embodiments of the present invention, the aspect ratio of the spinneret hole A is 3 to 6:1.

[0030] According to some embodiments of the present invention, the aspect ratio of the spinneret hole A is 3.5 to 5.5:1.

[0031] According to some embodiments of the present invention, the aspect ratio of the spinneret hole B is 1 to 3:1.

[0032] According to some embodiments of the present invention, the aspect ratio of the spinneret hole B is 1.5 to 2.5:1.

[0033] According to some embodiments of the present invention, the preparation method comprises the following steps:

[0034] S1: dividing the same fiber-forming polymer melt into melt A and melt B, wherein the spinneret is provided with spinneret hole A and spinneret hole B;

[0035] S2: the melt A enters the spinneret hole A and is spun to form fiber filaments A, and the melt B enters the spinneret hole B and is spun to form fiber filaments B;

[0036] S3: The fiber filaments A and B are brought together and bonded at a distance C from the spinneret to form parallel filaments;

[0037] S4: After cooling, stretching and heat treatment, the parallel yarns are formed into naturally curled elastic fibers.

[0038] According to some embodiments of the present invention, the distance C is ≥ 10 mm.

[0039] According to some embodiments of the present invention, the flow ratio of the melt A to the melt B is 1:0.5-2.

[0040] According to some embodiments of the present invention, the temperature of the melt A is higher than the temperature of the melt B by 5 to 50°C.

[0041] According to some embodiments of the present invention, the melt A and the melt B are further filtered before entering the spinneret.

[0042] According to some embodiments of the present invention, the filtering step includes: the melt first passes through filter sand, then passes through a filter sheet, and then enters a spinneret hole.

[0043] According to some embodiments of the present invention, before the melt passes through the filter sand, the melt is divided into two parts, one part is transported through a pipeline, metered by a metering pump A, and transported to component filter cup A through a melt pipeline, and the other part is transported through a pipeline, metered by a metering pump B, and transported to component filter cup B through a melt pipeline.

[0044] According to some embodiments of the present invention, the pre-filtration pressure of filter cup A is greater than the pre-filtration pressure of filter cup B of the component.

[0045] According to some embodiments of the present invention, a static or dynamic mixer may be installed in the melt pipeline as needed to improve the uniformity of heating or cooling.

[0046] According to some embodiments of the present invention, cooling may be air cooling with an air temperature of 10 to 25° C. and a speed of 0.2 to 0.5 m / s.

[0047] According to some embodiments of the present invention, the stretching is single-fold or multiple-fold stretching, the stretching temperature is 100 to 140 degrees, and the stretching multiple is 1.0 to 3 times. DETAILED DESCRIPTION

[0048] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0049] In a first aspect, some embodiments of the present invention provide a method for preparing elastic fibers, comprising dividing the same fiber-forming polymer melt into several parts, spraying them out through spinnerets with different apertures respectively and bonding them at the converging point.

[0050] It should be noted that the elastic fiber preparation method of the present invention uses the same fiber-forming polymer melt to be ejected through spinnerets with different apertures and then converged and bonded, and the elastic fiber produced only requires one melting device (i.e., one extruder). This method simplifies the equipment configuration and significantly reduces the equipment investment compared to the complex configuration of multiple melting devices required in the traditional process.

[0051] It can be understood that the preparation method of the elastic fiber of the present invention uses the same melt and the process design realizes the production of parallel elastic fibers through a low-energy melt direct spinning process. Therefore, compared with the traditional process of parallel compounding of different materials that requires high energy consumption, the present invention has lower energy consumption.

[0052] It can also be understood that the method for preparing elastic fibers of the present invention produces parallel curly yarns, and the fibers themselves have a single component. By using fiber materials of the same single component (rather than composites of heterogeneous materials), the produced fibers not only have good elasticity, but also exhibit performance close to that of new materials during physical recycling. This allows the recycled materials to be better reused, meets environmental protection requirements, and reduces energy consumption and difficulty in the recycling process. In particular, during chemical recycling, since a single polymer material is used, the monomer components after depolymerization are also relatively single, thereby reducing the complexity of the separation process and improving the recycling efficiency. And in most applications, it can be made into elastic fabrics alone, without the need to composite other highly elastic fibers. The performance of the polymer material after physical recycling is close to that of new materials, and is suitable for recycling.

[0053] The present invention realizes the curling structure of the fiber by dividing the same fiber-forming polymer melt into several parts and using spinnerets with different apertures. This curling effect gives the fiber excellent elastic properties, so that it can be used alone in most applications without compounding other highly elastic materials (such as spandex). Therefore, the elastic fiber produced can independently exert good performance in fabric manufacturing, reducing the dependence on other high-cost composite fibers.

[0054] Since the same material is used and the performance is close to that of new material through physical recycling, the present invention can effectively maintain the stability of material performance during the recycling process, avoiding performance fluctuations caused by the parallel compounding of different materials. The stability of this material can not only meet different industrial needs, but also make the recycled fiber have better comprehensive performance when it is used again, further improving the sustainability of the material.

[0055] In the present invention, the same fiber-forming polymer melt is divided into several parts, which are ejected through spinnerets of different diameters and bonded at the converging point, so that the natural curl of the fiber can be effectively achieved and the fiber is endowed with excellent elasticity. Specifically:

[0056] When the fiber filaments are ejected from spinnerets of different diameters, they shrink to different degrees. The thinner fiber filaments shrink relatively quickly due to the smaller tension, while the thicker fiber filaments shrink slowly. This difference causes the fiber to naturally form a curled state after cooling. The natural curling structure of the fiber has good resilience like a spring, which enables the fiber to quickly return to its original shape under the action of external force, showing excellent elastic recovery ability.

[0057] The present invention adjusts the diameter difference of the spinneret holes to make the fiber curl naturally during the production process, without the need for false twisting or external chemical treatment in the traditional method. This not only simplifies the production process, but also avoids the negative impact of chemical treatment on fiber properties (such as uneven dyeing or degradation of material properties).

[0058] The three-dimensional curled structure of the fiber enables it to quickly return to its original shape after the external force is released, providing a strong elastic recovery force. This structure is similar to a spring, which can significantly improve the elasticity of the fiber, making it more elastic and comfortable in fabrics, especially in the field of clothing, providing a better wearing experience.

[0059] By adjusting the difference in spinneret hole diameter, the curling degree and elastic effect of the fiber can be adjusted according to different needs, which has greater production flexibility. This means that during the production process, the fiber structure can be precisely controlled according to specific fiber elasticity requirements, thereby meeting the application requirements of various elastic textiles, such as elastic sportswear, underwear fabrics, etc.

[0060] The naturally curled fibers not only increase elasticity, but also make the fabric more three-dimensional and improve the comfort of the textile. The curled structure allows the fiber to evenly distribute stress when stretched, avoiding deformation or breakage that may be caused by direct stretching of the fiber, and improving the durability and comfort of the fabric.

[0061] The same fiber material is used and the fiber curling is achieved through physical means (spinneret hole design), without the need to add other high-cost or difficult-to-recycle highly elastic materials (such as spandex). Therefore, the produced fiber has good recyclability and meets the sustainable development requirements of modern fiber products. During the recycling process, the fiber can easily restore its performance through physical or chemical methods, reducing the difficulty of material recycling.

[0062] Therefore, the fiber preparation method of the present invention imparts excellent elasticity to the fiber by natural curling, while avoiding complicated post-processing processes, which not only improves the elastic effect of the fiber, but also makes the production process simpler and more efficient, meeting the requirements of environmental protection and sustainable development. These advantages make the elastic fiber of the present invention have important market competitiveness in the production and application of elastic textiles.

[0063] In conjunction with the first aspect, in some embodiments of the present invention, the fiber-forming polymer melt includes one of a polyamide melt and a polyester melt.

[0064] In combination with the first aspect, in some embodiments of the present invention, the polyamide melt includes polyamide 6, polyamide 66, polyamide 12, polyamide 56, polyamide 6 / 66, polyamide 66 / 6, polyamide 56 / 66 or polyamide 66 / 56.

[0065] Polyamide 6 / 66 refers to the copolymer of polyamide 6 and 66, which is the same material, not polyamide 6 and polyamide 66.

[0066] In combination with the first aspect, in some embodiments of the present invention, the number of the plurality of parts is 2.

[0067] In combination with the first aspect, in some embodiments of the present invention, the spinneret hole includes a spinneret hole A and a spinneret hole B, and the diameter of the spinneret hole A is greater than the diameter of the spinneret hole B.

[0068] In the present invention, the diameter of the spinneret hole A is larger than the diameter of the spinneret hole B. This design produces multiple beneficial effects in the preparation process of the elastic fiber:

[0069] The difference in diameter between spinneret A and spinneret B causes the fibers ejected through these two apertures to have different shrinkage rates during the cooling process. The fibers ejected from the thicker spinneret A shrink less and form larger fibers, while the fibers ejected from the thinner spinneret B shrink more and form smaller fibers. As the fibers with different shrinkage rates are brought together and bonded in the subsequent process, they form a naturally curled structure with different elastic recovery capabilities. Such a structure is similar to a spring and can restore its shape more effectively, thereby significantly improving the elastic effect of the fiber.

[0070] The difference in diameter between spinneret A and spinneret B results in different elastic recovery behaviors of coarse and fine fibers during the process of fiber curling. Coarser fibers have better stretchability and strength, while finer fibers have stronger elastic recovery capabilities. Through this design, the fiber can quickly recover to its original shape after being stretched and subjected to external forces, providing better elastic effects and suitable for fabric applications with high elasticity requirements.

[0071] Fine fibers and coarse fibers can interweave and work together in the fabric to form a three-dimensional surface structure. Fine fibers provide a softer feel and better comfort, while coarse fibers provide stronger structural support and durability. In this way, the fabric can maintain elasticity while ensuring a certain strength and durability, improving the overall comfort and service life of the textile.

[0072] Using spinnerets with different apertures can control the shrinkage characteristics and elasticity of the fiber according to actual needs. By adjusting the diameter difference between spinneret A and spinneret B, the curling degree of the fiber, the elastic effect and the comfort of the fabric can be accurately adjusted, which improves the flexibility and adjustability of the production process.

[0073] Compared with the traditional composite fiber manufacturing method that requires multiple process steps or high-energy consumption equipment, different elastic effects can be achieved by simply adjusting the diameter difference of the spinneret hole, which reduces the complex subsequent processing process, thereby reducing energy consumption and material waste in the production process. This design makes the production of elastic fibers more efficient and energy-saving.

[0074] Since the present invention uses the same fiber-forming polymer melt, the fibers ejected through spinnerets with different apertures still maintain a uniform material composition, which makes fiber recycling easier. During the recycling process, there is no need to worry about the mixing of material types, and high performance stability can be maintained during physical recycling, while reducing the difficulty of separation during the recycling process.

[0075] Therefore, the diameter difference design of spinneret A and spinneret B can effectively optimize the shrinkage, curling and elastic recovery performance of the fiber, improve the elastic effect and comfort of the fiber, and simplify the production process, reduce energy consumption and material waste. This design provides a better solution for the efficient production and recycling of elastic fibers, with significant economic and environmental advantages.

[0076] In combination with the first aspect, in some embodiments of the present invention, the ratio of the diameter of the spinneret hole A to the diameter of the spinneret hole B is 1.5-5:1.

[0077] When the ratio of the diameter of the spinneret hole A to the diameter of the spinneret hole B is 1.5 to 5:1, the following beneficial effects are achieved:

[0078] The diameter ratio of spinneret A and spinneret B is set between 1.5 and 5:1, so that the fiber filaments ejected from the two diameter spinnerets show obvious shrinkage differences when cooling. The fibers produced by the larger pore size (spinneret A) shrink less during the cooling process, while the fibers produced by the smaller pore size (spinneret B) shrink more. With this design, the shrinkage difference of the fibers is more significant, forming a tighter and elastic natural curling structure after the fibers are gathered. The enhanced curling effect improves the elasticity and resilience of the fibers, allowing the fibers to better recover to their original shape after being subjected to force.

[0079] By adjusting the diameter ratio of spinneret A and spinneret B, the elasticity and comfort of the fiber can be precisely controlled. The larger spinneret A forms thicker fibers, providing stronger mechanical properties (such as strength and wear resistance), while the smaller spinneret B forms thinner fibers, providing higher elasticity and softness. The diameter ratio is within the range of 1.5 to 5:1, so that the elastic effect of the fiber can meet the requirements of high elastic fabrics while maintaining good comfort and performance.

[0080] When the diameter of the spinneret holes varies greatly (such as 1.5 to 5:1), fibers of different diameters can form a more stable three-dimensional curling structure when interwoven together. This structure not only enhances the resilience of the fibers, but also improves the three-dimensional sense and support of the fibers, and enhances the elasticity and comfort of the fabric. Compared with smaller diameter differences, larger diameter differences make the physical interaction between the fibers more complex, further enhancing the three-dimensional elastic effect of the fibers.

[0081] Since the fibers ejected from the larger aperture (spinneret A) are thicker, they have stronger stretchability and can withstand greater external forces; while the fibers ejected from the smaller aperture (spinneret B) have better elastic recovery when stretched. By setting a reasonable ratio, the fibers can maintain their shape after stretching and quickly return to their original shape, greatly improving the elastic recovery ability of the fabric, making it suitable for fabrics that require high elasticity, such as sportswear, stretch denim, etc.

[0082] Setting the diameter ratio of spinneret A to spinneret B to 1.5 to 5:1 can produce fiber products with different elasticity requirements. With this ratio, manufacturers can adjust the size of the spinneret according to actual needs, thereby achieving fine control of the fiber structure, elasticity and comfort. This design makes the production process more flexible, can meet the manufacturing needs of different elastic fibers, and improves the diversity and efficiency of production.

[0083] Since the same raw materials are used and the fiber structure is controlled by spinnerets of different apertures, rather than relying on the combination of different types of materials, the fiber recycling process is relatively simple. The fiber can easily restore its performance after recycling, especially in the physical recycling process. Due to the single material composition of the fiber, the performance after recycling is close to that of the new material, further improving the sustainability and environmental protection of the material.

[0084] In the fiber production process, the use of a spinneret diameter ratio of 1.5 to 5:1 can reduce the reliance on complex processes and improve fiber production efficiency. Because only one melt raw material is needed to achieve the ideal elastic effect, there is no need for multiple complex post-processing processes or the use of additional high-elastic fibers (such as spandex). This not only saves energy consumption in the production process, but also reduces production costs.

[0085] In summary, the design of a 1.5-5:1 ratio of the diameter of spinneret A to spinneret B improves the natural curling, elastic recovery, comfort and recycling performance of the fiber by optimizing the shrinkage difference and elastic effect of the fiber, while also providing greater flexibility and efficiency for production. This design not only meets the demand for high-elastic textiles, but also meets the requirements of modern environmental protection and sustainable development, and has high economic and practical value.

[0086] In combination with the first aspect, in some embodiments of the present invention, the aspect ratio of the spinneret hole A is 3 to 6:1.

[0087] The higher aspect ratio makes the ejected fibers more slender, more uniform and more stable in shape. This design of the spinneret hole A can avoid excessive deformation or irregularity of the fibers during the formation process, help produce fibers with a flat and smooth surface, and improve the overall appearance quality of the textile.

[0088] In combination with the first aspect, in some embodiments of the present invention, the aspect ratio of the spinneret hole A is 3.5-5.5:1.

[0089] In combination with the first aspect, in some embodiments of the present invention, the aspect ratio of the spinneret hole B is 1 to 3:1.

[0090] In combination with the first aspect, in some embodiments of the present invention, the aspect ratio of the spinneret hole B is 1.5-2.5:1.

[0091] When the aspect ratio of spinneret B is 1.5 to 2.5:1, the uniformity of the fiber and the tensile properties of the yarn can be effectively improved, the strength and gloss of the fiber can be improved, and the possibility of spinneret blockage can be reduced. This aspect ratio design makes the melt flow more stable, helps to produce more delicate and higher quality fiber products, and improves the overall performance of textile materials.

[0092] In combination with the first aspect, in some embodiments of the present invention, the preparation method comprises the following steps:

[0093] S1: The same fiber-forming polymer melt is divided into melt A and melt B, and a spinneret is provided with spinneret hole A and spinneret hole B;

[0094] S2: melt A enters spinneret hole A and is spun to form fiber A, melt B enters spinneret hole B and is spun to form fiber B;

[0095] S3: Fiber A and fiber B converge and bond at a distance C from the spinneret to form parallel filaments;

[0096] S4: After cooling, stretching and heat treatment, the parallel yarns form naturally curled elastic fibers.

[0097] In combination with the first aspect, in some embodiments of the present invention, the distance C is ≥ 10 mm.

[0098] In some embodiments of the present invention, the setting of distance C ≥ 10 mm helps to enhance the bonding effect between fiber filaments A and fiber filaments B. A larger distance C allows the melt to be more fully mixed and shaped in the spinneret hole, ensuring that fiber filaments A and fiber filaments B can be more evenly fused when converging to form parallel filaments. This can effectively control the structural stability and elasticity of the fiber, avoiding premature excessive bonding or uneven bonding. In addition, a larger convergence distance C helps to improve the tensile properties and overall elasticity of the fiber, ultimately forming a softer, naturally curled elastic fiber, which is suitable for the manufacture of high-performance textiles.

[0099] In combination with the first aspect, in some embodiments of the present invention, the flow ratio of melt A to melt B is 1:0.5-2.

[0100] The flow ratio of melt A to melt B of 1:0.5-2 helps optimize the structure and properties of the fiber. The appropriate flow ratio ensures that the two melts are evenly distributed during the spinning process, avoiding uneven fiber formation, while adjusting the strength and elasticity of the fiber and improving the softness and elasticity of the final product. In addition, a reasonable flow ratio helps improve the stability and efficiency of the production process, reduce waste, and ensure the production of high-quality elastic fibers.

[0101] In combination with the first aspect, in some embodiments of the present invention, the temperature of melt A is higher than the temperature of melt B by 5 to 50°C.

[0102] The temperature of melt A is 5 to 50°C higher than that of melt B, which helps optimize the fluidity and adhesion of the two melts. The higher temperature of melt A can make it easier to flow during the spinning process and promote the formation of fiber filaments A, while the lower temperature of melt B helps maintain its high viscosity and ensures that fiber filaments A and fiber filaments B can be better bonded when they are gathered. Such a temperature difference helps control the structure and properties of the fiber, improve the uniformity, elasticity and strength of the fiber, and ultimately obtain high-quality elastic fibers.

[0103] In combination with the first aspect, in some embodiments of the present invention, melt A and melt B are further filtered before entering the spinneret hole.

[0104] In combination with the first aspect, in some embodiments of the present invention, the filtering step includes: the melt first passes through filter sand, then passes through a filter sheet, and then enters a spinneret hole.

[0105] In combination with the first aspect, in some embodiments of the present invention, before the melt passes through the filter sand, the melt is divided into two parts, one part is transported through a pipeline, measured by a metering pump A, and transported to a component filter cup A through a melt pipeline, and the other part is transported through a pipeline, measured by a metering pump B, and transported to a component filter cup B through a melt pipeline.

[0106] In combination with the first aspect, in some embodiments of the present invention, the pre-filtration pressure of filter cup A is greater than the pre-filtration pressure of filter cup B of the component.

[0107] The greater pre-filter pressure of filter cup A than that of component filter cup B helps optimize the fluid distribution and filter media usage efficiency during the filtration process. The higher pre-filter pressure can increase the flow velocity of the filtrate, ensuring a higher filtration efficiency of filter cup A, thereby more effectively removing impurities. The relatively lower pre-filter pressure in filter cup B can reduce excessive clogging and premature filter media loss, help extend the service life of filter cup B, and ensure the stability of the filtration process. This pressure difference optimizes the overall performance of the filtration system, improves filtration efficiency and the service life of the equipment.

[0108] In combination with the first aspect, in some embodiments of the present invention, a static or dynamic mixer can be installed in the melt pipeline as needed to improve the uniformity of heating or cooling.

[0109] In combination with the first aspect, in some embodiments of the present invention, cooling may be air cooling with an air temperature of 10 to 25° C. and a speed of 0.2 to 0.5 m / s.

[0110] In combination with the first aspect, in some embodiments of the present invention, the stretching is single-fold or multiple-fold stretching, the stretching temperature is 100 to 140°C, and the stretching multiple is 1.0 to 3 times.

[0111] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0112] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0113] Unless otherwise specified, "room temperature" in the present invention means 25°C±5°C.

[0114] Unless otherwise specified, "about" in the present invention means that the allowable error is within ±2%.

[0115] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0116] Example 1

[0117] An elastic fiber was prepared:

[0118] The equipment is a Φ35 single screw extruder with split components;

[0119] Melting by single screw extruder, the temperature of single screw extruder is 210℃, 240℃, 250℃, 250℃;

[0120] The material is polyamide 6 (Xinhui Meida, brand M2403);

[0121] The spinning specification is 40 / 12 (40 is the fineness, which is related to the thickness, and 12 is the number of strands. There are 12 strands in this bundle of silk);

[0122] The flow ratio of melt pump A and melt pump B is 1:1;

[0123] Pipeline A is equipped with a static mixer, heating jacket, air cooling, and a set temperature of 270°C;

[0124] After melt pump A, the inlet temperature of component filter cup A is 270°C;

[0125] The initial pressure of component filter cup A is 120MPa;

[0126] The diameter of spinneret hole A is 0.1 mm, and the aspect ratio is 4:1;

[0127] Pipeline B has a static mixer, heating jacket, air cooling, and a set temperature of 240°C;

[0128] After melt pump B, the inlet temperature of component filter cup B is 245°C;

[0129] The initial pressure of component filter cup B is 80MPa;

[0130] The diameter of spinneret B is 0.4 mm, and the aspect ratio is 2:1;

[0131] Cooling is air cooling, and the side air temperature is 18℃;

[0132] Winding speed 4000m / min;

[0133] The stretching was 1.2 times, and the stretching setting temperature was 130°C.

[0134] Example 2

[0135] An elastic fiber was prepared:

[0136] The equipment is a Φ35 single screw extruder with split components;

[0137] Melting by single screw extruder, the temperature of single screw extruder is 210℃, 240℃, 250℃, 250℃;

[0138] The material is polyamide 6 (Xinhui Meida, brand M32800);

[0139] The spinning specification is 40 / 12 (40 is the fineness, which is related to the thickness, and 12 is the number of strands. There are 12 strands in this bundle of silk);

[0140] The flow ratio of melt pump A and melt pump B is 1:0.8;

[0141] Pipeline A is equipped with a static mixer, heating jacket, air cooling, and a set temperature of 270°C;

[0142] After melt pump A, the inlet temperature of component filter cup A is 285°C;

[0143] The initial pressure of component filter cup A is 136MPa;

[0144] The diameter of spinneret hole A is 0.1 mm, and the aspect ratio is 4:1;

[0145] Pipeline B has a static mixer, heating jacket, air cooling, and a set temperature of 240°C;

[0146] After melt pump B, the inlet temperature of component filter cup B is 260°C;

[0147] The initial pressure of component filter cup B is 87MPa;

[0148] The diameter of spinneret B is 0.4 mm, and the aspect ratio is 2:1;

[0149] Cooling is air cooling, and the side air temperature is 18℃;

[0150] Winding speed 3800m / min;

[0151] The stretching was 1.25 times, and the stretching setting temperature was 130°C.

[0152] Example 3

[0153] An elastic fiber was prepared:

[0154] The equipment is a Φ35 single screw extruder with split components;

[0155] Melting by single screw extruder, the temperature of single screw extruder is 210℃, 240℃, 250℃, 250℃;

[0156] The material is polyamide 6 (Xinhui Meida, brand M2403);

[0157] The spinning specification is 30 / 12 (30 is the fineness, which is related to the thickness, and 12 is the number of strands. There are 12 strands in this bundle of silk);

[0158] The flow ratio of melt pump A and melt pump B is 1:1;

[0159] Pipeline A is equipped with a static mixer, heating jacket, air cooling, and a set temperature of 270°C;

[0160] After melt pump A, the inlet temperature of component filter cup A is 270°C;

[0161] The initial pressure of component filter cup A is 120MPa;

[0162] The diameter of spinneret hole A is 0.1 mm, and the aspect ratio is 4:1;

[0163] Pipeline B has a static mixer, heating jacket, air cooling, and a set temperature of 240°C;

[0164] After melt pump B, the inlet temperature of component filter cup B is 245°C;

[0165] The initial pressure of component filter cup B is 80MPa;

[0166] The diameter of spinneret B is 0.4 mm, and the aspect ratio is 2:1;

[0167] Cooling is air cooling, and the side air temperature is 18℃;

[0168] Winding speed 4500m / min;

[0169] The stretching was 1.2 times, and the stretching setting temperature was 130°C.

[0170] Example 4

[0171] An elastic fiber was prepared:

[0172] The equipment is a Φ35 single screw extruder with split components;

[0173] Melting by single screw extruder, the temperature of single screw extruder is 210℃, 240℃, 250℃, 250℃;

[0174] The material is polyamide 6 / 66 (Xinhui Meida, brand M97C28);

[0175] The spinning specification is 30 / 12 (30 is the fineness, which is related to the thickness, and 12 is the number of strands. There are 12 strands in this bundle of silk);

[0176] The flow ratio of melt pump A and melt pump B is 1:1;

[0177] Pipeline A is equipped with a static mixer, heating jacket, air cooling, and a set temperature of 270°C;

[0178] After melt pump A, the inlet temperature of component filter cup A is 280°C;

[0179] The initial pressure of component filter cup A is 116MPa;

[0180] The diameter of spinneret hole A is 0.1 mm, and the aspect ratio is 4:1;

[0181] Pipeline B has a static mixer, heating jacket, air cooling, and a set temperature of 240°C;

[0182] After melt pump B, the inlet temperature of component filter cup B is 235°C;

[0183] The initial pressure of component filter cup B is 80MPa;

[0184] The diameter of spinneret B is 0.4 mm, and the aspect ratio is 2:1;

[0185] Cooling is air cooling, and the side air temperature is 18℃;

[0186] Winding speed 400m / min;

[0187] The stretching was 1.2 times, and the stretching setting temperature was 130°C.

[0188] Comparative Example 1

[0189] An elastic fiber was prepared:

[0190] The equipment is a Φ35 single screw extruder with split components;

[0191] Melting by single screw extruder, the temperature of single screw extruder is 210℃, 240℃, 250℃, 250℃;

[0192] The material is polyamide 6 (Xinhui Meida, brand M2403);

[0193] The spinning specification is 40 / 12 (40 is the fineness, which is related to the thickness, and 12 is the number of strands. There are 12 strands in this bundle of silk);

[0194] The flow ratio of melt pump A and melt pump B is 0.2:1;

[0195] Pipeline A is equipped with a static mixer, heating jacket, air cooling, and a set temperature of 270°C;

[0196] After melt pump A, the inlet temperature of component filter cup A is 270°C;

[0197] The initial pressure of component filter cup A is 120MPa;

[0198] The diameter of spinneret hole A is 0.1 mm, and the aspect ratio is 4:1;

[0199] Pipeline B has a static mixer, heating jacket, air cooling, and a set temperature of 240°C;

[0200] After melt pump B, the inlet temperature of component filter cup B is 245°C;

[0201] The initial pressure of component filter cup B is 80MPa;

[0202] The diameter of spinneret B is 0.4 mm, and the aspect ratio is 2:1;

[0203] Cooling is air cooling, and the side air temperature is 18℃;

[0204] Winding speed 4000m / min;

[0205] The stretching was 1.2 times, and the stretching setting temperature was 130°C.

[0206] Comparative Example 2

[0207] An elastic fiber was prepared:

[0208] The equipment is a Φ35 single screw extruder with split components;

[0209] Melting by single screw extruder, the temperature of single screw extruder is 210℃, 240℃, 250℃, 250℃;

[0210] The material is polyamide 6 (Xinhui Meida, brand M2403);

[0211] The spinning specification is 40 / 12 (40 is the fineness, which is related to the thickness, and 12 is the number of strands. There are 12 strands in this bundle of silk);

[0212] The flow ratio of melt pump A and melt pump B is 1:1;

[0213] Pipeline A is equipped with a static mixer, heating jacket, air cooling, and a set temperature of 270°C;

[0214] After melt pump A, the inlet temperature of component filter cup A is 260°C;

[0215] The initial pressure of component filter cup A is 133MPa;

[0216] The diameter of spinneret hole A is 0.4 mm, and the aspect ratio is 2:1;

[0217] Pipeline B has a static mixer, heating jacket, air cooling, and a set temperature of 240°C;

[0218] After melt pump B, the inlet temperature of component filter cup B is 260°C;

[0219] The initial pressure of component filter cup B is 68MPa;

[0220] The diameter of spinneret B is 0.4 mm, and the aspect ratio is 2:1;

[0221] Cooling is air cooling, and the side air temperature is 18℃;

[0222] Winding speed 4000m / min;

[0223] The stretching was 1.2 times, and the stretching setting temperature was 130°C.

[0224] Performance Testing

[0225] The breaking strength, curl shrinkage and curl stability of the elastic fibers prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were tested. The results are shown in Table 1.

[0226] Table 1

[0227] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Breaking strength cN / dtex 3.6 3.8 3.7 3.7 3.9 3.8 Curl shrinkage % 43 48 49 47 24 13 Curl stability % 91.3 92 92 92 92 91

[0228] According to the data in Table 1, we can see that:

[0229] About breaking strength (cN / dtex):

[0230] The breaking strength of Examples 1 to 4 is 3.6-3.8 cN / dtex, showing a relatively consistent strength level. These values ​​are close to the strength of Comparative Example 1 (3.8) and Comparative Example 2 (3.9), indicating that the difference between the Examples and Comparative Examples in terms of strength is not large. The higher breaking strength means that these fibers have better tensile resistance.

[0231] About curl shrinkage (%):

[0232] The curl shrinkage of the examples is generally high, ranging from 43% to 49%, which is significantly higher than that of Comparative Example 1 (13%) and Comparative Example 2 (24%). This indicates that the fibers in the examples have strong natural curls and can produce more elasticity and fluffiness during use. In contrast, the curl shrinkage of the comparative examples is significantly lower, which may mean that these fibers are less curled, straighter, and lack a certain degree of elasticity.

[0233] About curl stability (%):

[0234] The curl stability of Examples 1 to 4 is between 91.3% and 92%, showing good curl persistence and high stability.

[0235] The fiber in the embodiment has a high curl shrinkage rate and good curl stability, showing strong elasticity and good durability, and is suitable for applications requiring high elasticity and curling effects. Although the breaking strength is comparable to that of the control group, the curling performance of the embodiment is significantly better than that of the control group, indicating that the fiber in the embodiment of the present invention has more advantages in elasticity and fluffiness.

[0236] The present invention has been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A method for preparing an elastic fiber, characterized in that: The method comprises dividing the same fiber-forming polymer melt into several parts, spraying them out through spinneret holes of different apertures respectively and bonding them at the converging point.

2. The preparation method according to claim 1, characterized in that: The fiber-forming polymer melt includes one of a polyamide melt and a polyester melt.

3. The preparation method according to claim 1, characterized in that: The number of the plurality of parts is 2.

4. The preparation method according to claim 1, characterized in that: The spinneret holes include a spinneret hole A and a spinneret hole B, and the diameter of the spinneret hole A is greater than the diameter of the spinneret hole B.

5. The preparation method according to claim 4, characterized in that: The ratio of the diameter of the spinneret hole A to the diameter of the spinneret hole B is 1.5 to 5:

1.

6. The preparation method according to claim 4, characterized in that: The aspect ratio of the spinneret hole A is 3 to 6:

1.

7. The preparation method according to claim 4, characterized in that: The aspect ratio of the spinneret hole B is 1 to 3:

1.

8. The preparation method according to any one of claims 1 to 7, characterized in that The following steps are involved: S1: The same fiber-forming polymer melt is divided into melt A and melt B, and a spinneret is provided with spinneret hole A and spinneret hole B; S2: the melt A enters the spinneret hole A and is spun to form fiber filaments A, and the melt B enters the spinneret hole B and is spun to form fiber filaments B; S3: the fiber filaments A and B are brought together and bonded at a distance C from the spinneret to form parallel filaments; S4: After cooling, stretching and heat treatment, the parallel yarns are formed into naturally curled elastic fibers.

9. The preparation method according to claim 8, characterized in that: The flow ratio of the melt A to the melt B is 1:0.5-2; and / or the temperature of the melt A is higher than the temperature of the melt B by 5-50°C.

10. The preparation method according to claim 8, characterized in that: The melt A and the melt B are filtered before entering the spinneret hole.