Lightweight down-like synthetic fiber and method for producing the same

Abstract

The application provides a light-weighted synthetic fiber imitating down and a preparation method thereof, wherein a thermoplastic polymer for two-phase separation is selected as a sea phase material and an island phase material, the two are used as skin layer raw materials, a polymer compatible with the two-phase island phase polymer is used as a core layer raw material, a nascent fiber is prepared through an island / sea skin core melt spinning technology method, and the nascent fiber is soaked in an organic solvent to remove the sea phase polymer, so as to obtain the light-weighted synthetic fiber imitating down. The core layer main stem fiber and the skin layer nanometer short fiber of the light-weighted synthetic fiber imitating down are compatible with each other, the two are bonded in a melt spinning process, an integrated structure is formed, the synthetic fiber is not easy to deform, has good durability, the mechanical properties and practicability of the synthetic fiber imitating down are improved, the skin layer nanometer short fiber has a disordered structure, air is filled between the short fibers, the fiber becomes more fluffy, the composite fiber with the structure has good heat preservation effect, and has wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of fiber technology, and in particular to a lightweight down-like synthetic fiber and its preparation method. Background Technology

[0002] Down is a mixture of feathers and down. Feathers, as the structure of feathers, provide support and allow the down to quickly rebound. Down, as a filament structure, consists of numerous down fibers forming a cluster that traps a large amount of stagnant air, giving it excellent warmth retention. Compared to down, fibers such as cotton, silk, synthetic fibers, and wool are linear, containing less trapped air and prone to clumping over time, affecting warmth and comfort. Down, however, does not have this clumping problem and remains fluffy even after long-term use, making it stand out among insulation materials. While natural down possesses properties such as fluffiness, warmth, smoothness, and softness, it is expensive, difficult to source, and its processing is complex and inefficient in order to meet the microbial content standards for fabrics. This has created an opportunity for the development of down-like products.

[0003] In the prior art, an invention patent (application number CN 201710548272.9) discloses a down-like fiber, which includes a thermoplastic polymer body and at least 11 pores extending along the axial direction of the thermoplastic polymer body. The pore diameter is 0.14 μm or larger, and the fineness of a single fiber is 0.4D or larger and 5D or smaller. This down-like fiber has a porous hollow structure and is composed of a porous thermoplastic polymer body. It is lightweight and has high heat retention, making it suitable as a filling material for down jackets. However, this material imparts its heat retention effect through the pores in the thermoplastic polymer, but due to the influence of fiber diameter, the pore filling is limited, and the heat retention performance cannot be further improved.

[0004] An invention patent (application number CN 202211463908.7) discloses a down-like wadding and its preparation method. The down-like wadding is composed of a composite of skeletal fibers and microfibers. The skeletal fibers are one or more of two-dimensional synthetic fibers and three-dimensional crimped hollow fibers, while the microfibers are microfibers of ultrafine polypropylene fibers. The preparation method involves using a blower to combine the microfibers and skeletal fibers, achieving thorough mixing to form the down-like wadding. However, the resulting down-like wadding has poor overall integrity and poor bonding between the skeletal fibers and microfibers, making it prone to separation or clumping during application, thus affecting its warmth retention.

[0005] In view of this, it is necessary to design an improved lightweight down-like synthetic fiber and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a lightweight down-like synthetic fiber and its preparation method. Two-phase thermoplastic polymers are selected as marine and island phase materials, respectively. Nascent fibers are prepared using an island / core-sheath melt spinning technique. The nascent fibers are then immersed in an organic solvent to remove the marine polymer, resulting in a lightweight down-like synthetic fiber containing core backbone fibers and sheath nanofibers. The sheath nanofibers of this down-like synthetic fiber are filled with a large amount of air, giving it excellent heat insulation properties.

[0007] To achieve the above-mentioned objective, this invention provides a method for preparing lightweight down-like synthetic fibers, comprising the following steps: S1. Select a thermoplastic polymer as the island phase polymer, and select a thermoplastic polymer that is incompatible with the island phase polymer as the marine phase polymer, wherein the marine phase polymer is a polymer soluble in organic solvents; S2. The island-phase polymer and the marine-phase polymer are blended and granulated to serve as the skin layer raw material, wherein the mass percentage of the island-phase polymer to the marine-phase polymer is (10%~30%):(70%~90%). S3. Select a polymer that is compatible with the island phase polymer as the core layer raw material, and prepare nascent fibers with a core-shell structure by using core-shell melt spinning technology to combine the skin layer raw material and the core layer raw material. S4. The nascent fibers obtained in step S3 are immersed in an organic solvent to remove the marine polymer in the cortex, thereby obtaining a lightweight down-like synthetic fiber. The lightweight down-like synthetic fiber comprises a core backbone fiber and a cortex nanofiber, wherein the core backbone fiber and the cortex nanofiber are an integrated structure that is mutually bonded. The diameter of the core backbone fiber is 5-15 μm, and the diameter of the cortex nanofiber is 50-800 nm, and the length is 100-5000 nm.

[0008] As a further improvement of the present invention, in step S1, the island phase polymer also contains heat-generating nanoparticles with photothermal conversion properties, wherein the particle size of the heat-generating nanoparticles is 50~500nm.

[0009] As a further improvement of the present invention, in step S1, the marine polymer includes one of polystyrene, polyethylene, and cellulose acetate, and the corresponding organic solvent is selected from toluene, xylene, or acetone.

[0010] As a further improvement of the present invention, in step S3, the melting temperature of the core-sheath melt spinning technology is higher than the melting point of the sheath material and the core material.

[0011] As a further improvement of the present invention, in step S1, the thermoplastic polymer, which is an island phase polymer, includes one of polyester, nylon, and polyolefin.

[0012] As a further improvement of the present invention, in step S3, the core layer raw material also contains an antibacterial agent, which is added to the core layer raw material during melt spinning.

[0013] As a further improvement of the present invention, the heating nanoparticles include one or more of carbon powder and group IV metal carbides.

[0014] As a further improvement of the present invention, the antibacterial agent includes one or more of nano-silver, nano-copper, nano-zinc, guanidine salt, and quaternary ammonium salt.

[0015] The beneficial effects of this invention are: 1. This invention discloses a lightweight down-like synthetic fiber and its preparation method. Two-phase thermoplastic polymers are selected as marine and island phase materials, respectively. The marine and island phase materials are blended as the outer layer raw material, and a polymer compatible with the island phase polymer is used as the core layer raw material. Nascent fibers are prepared using an island / outer-core melt spinning technique. The nascent fibers are then immersed in an organic solvent to remove the marine phase polymer, resulting in a lightweight down-like synthetic fiber containing core layer backbone fibers and outer layer nanofibers. The down-like synthetic fiber of this invention has a large amount of air filling the spaces between the outer layer nanofibers, giving it excellent heat insulation properties. Furthermore, the preparation method is simple and easy to implement, suitable for industrial mass production.

[0016] 2. The lightweight down-like synthetic fiber prepared by the method of the present invention uses a two-phase compatible thermoplastic polymer for its core backbone fiber and sheath nanofibers. During melt spinning, the two fibers adhere to each other through the movement of molecular chains, causing the sheath nanofibers to firmly adhere to the core backbone fiber, forming an integrated structure. This makes the synthetic fiber less prone to deformation, has good durability, and improves the mechanical properties and practicality of the down-like fiber. In addition, the sheath nanofibers have a disordered structure, with air filling the spaces between the fibers, making the fiber more fluffy. Furthermore, the poor thermal conductivity of air gives the fiber with good heat insulation properties.

[0017] 3. The lightweight down-like synthetic fiber of the present invention also contains heat-generating nanoparticles with photothermal conversion properties and antibacterial agents, which makes the fiber not only have good heat conversion properties under light, but also excellent heat preservation and antibacterial effects. Moreover, it is inexpensive, has a simple preparation process, and has broad application prospects. Attached Figure Description

[0018] Figure 1 Microscopic electron microscope image of the cross-section of the nascent fiber prepared in Example 1 of this invention. Figure 2 The image shows a cross-sectional electron microscope image of the lightweight down-like synthetic fiber prepared in Example 1. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0021] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0022] A method for preparing a lightweight down-like synthetic fiber includes the following steps: S1. Select a thermoplastic polymer as the island phase polymer and a thermoplastic polymer that is incompatible with the island phase polymer as the marine phase polymer. The marine phase polymer is a polymer that is soluble in organic solvents. S2. The island-phase polymer and the marine-phase polymer are blended and granulated to be used as the skin layer raw material. The mass percentage of the island-phase polymer to the marine-phase polymer is (10%~30%): (70%~90%). S3. Select a polymer that is compatible with the island phase polymer as the core layer material, and prepare nascent fibers with a sheath-core structure by using sheath-core melt spinning technology; wherein, the melting temperature of the sheath-core melt spinning technology is higher than the melting point of the sheath material and the core material. S4. The nascent fibers from step S3 are soaked in an organic solvent to remove the marine polymer in the cortex, thereby obtaining a lightweight down-like synthetic fiber. The lightweight down-like synthetic fiber includes a core backbone fiber and a cortex nanofiber, wherein the core backbone fiber and the cortex nanofiber are an integrated structure that is mutually bonded. The diameter of the core backbone fiber is 5-15 μm, and the diameter of the cortex nanofiber is 50-800 nm, and the length is 100-5000 nm.

[0023] Specifically, the lightweight down-like synthetic fiber obtained by this preparation method uses a two-phase compatible thermoplastic polymer or directly uses the same type of thermoplastic polymer for its core backbone fibers and sheath nanofibers. During melt spinning, the two fibers adhere to each other through the movement of molecular chains, causing the sheath nanofibers to firmly adhere to the core backbone fibers, forming an integrated structure. This makes the synthetic fiber less prone to deformation, has good durability, and improves the mechanical properties and practicality of the down-like fiber. In addition, the sheath nanofibers have a disordered structure, with air filling the spaces between the fibers, making the fibers more fluffy. Furthermore, the poor thermal conductivity of air gives the fiber structure excellent heat insulation properties.

[0024] Specifically, in step S1, the island-phase polymer also contains heat-generating nanoparticles with photothermal conversion properties, and the particle size of the heat-generating nanoparticles is 50~500nm. By adding heat-generating nanoparticles to the island-phase polymer, it is made to have photothermal conversion properties. After the island-phase polymer is used as a skin material to prepare lightweight down-like synthetic fiber, the heat-generating nanoparticles are located on the surface of the synthetic fiber, which can better exert the photothermal properties.

[0025] More specifically, the marine polymer includes one of polystyrene, polyethylene, and cellulose acetate, and the corresponding organic solvent is toluene, xylene, or acetone; that is, when polystyrene is used as the marine polymer, toluene is used as the organic solvent, when polyethylene is used as the marine polymer, xylene is used as the organic solvent, and when cellulose acetate is used as the marine polymer, acetone is used as the organic solvent. In this way, the marine polymer in the skin layer can be removed more effectively, and skin nanofibers made from the island polymer are obtained.

[0026] In some specific embodiments, in step S1, the thermoplastic polymer in the island phase polymer includes one of polyester, nylon, and polyolefin.

[0027] In some specific embodiments, in step S3, the core layer material also contains an antibacterial agent; the antibacterial agent includes one or more of nano-silver, nano-copper, nano-zinc, guanidine salt, and quaternary ammonium salt. The antibacterial agent is placed in the core layer material, which not only ensures the antibacterial properties of the down-like synthetic fiber, but also prevents the antibacterial agent from shedding or attenuating because it is located in the main core fiber.

[0028] In some specific embodiments, the exothermic nanoparticles include one or more of carbon powder and group IV metal carbides.

[0029] A lightweight down-like synthetic fiber comprises a core layer of main fibers and a sheath layer of short nanofibers, which are interconnected in an integrated structure. The core layer of main fibers has a diameter of 5-15 μm; the sheath layer of short nanofibers has a diameter of 50-800 nm and a length of 100-5000 nm. The down-like synthetic fiber of this invention incorporates a large amount of air between the sheath layer of short nanofibers, giving it excellent heat insulation properties; moreover, the preparation method is simple and easy to implement, suitable for industrial mass production. Example 1 This embodiment provides a lightweight down-like synthetic fiber and its preparation method, including the following steps: S1. Polyester is selected as the island phase polymer, and cellulose acetate ester, which is incompatible with the island phase polymer, is selected as the marine phase polymer. S2. The island-phase polymer and the marine-phase polymer are blended and granulated to be used as the skin layer raw material. The mass ratio of the island-phase polymer to the marine-phase polymer is 10%:90% by mass. S3. Select a polyester of the same type as the island phase polymer as the core layer raw material, melt the sheath material and the core layer raw material, and prepare nascent fibers with a sheath-core structure through sheath-core melt spinning technology; wherein, the melting temperature is 290℃. S4. Soak the nascent fibers from step S3 in acetone to remove the marine polymer in the cortex, thus obtaining lightweight down-like synthetic fibers.

[0030] Please see Figures 1-2 As shown, Figure 1 This is a cross-sectional electron microscope image of the nascent fibers prepared in Example 1. Figure 2 The image shows a cross-sectional electron microscope (EM) image of the lightweight down-like synthetic fiber prepared in Example 1. As can be seen from the image, the nascent fiber prepared by core-sheath melt spinning technology has a distinct core-sheath structure. Figure 2 As can be seen, the lightweight down-like synthetic fiber prepared in this embodiment includes a core layer backbone fiber and a sheath nanofiber, with the sheath nanofiber firmly bonded to the surface of the core layer backbone fiber.

[0031] Example 2 This embodiment provides a method for preparing lightweight down-like synthetic fibers. Compared with Example 1, the difference is that in step S1, polystyrene is selected as the marine polymer and toluene is selected as the organic solvent. The rest is roughly the same as in Example 1, and will not be repeated here.

[0032] Example 3 This embodiment provides a method for preparing lightweight down-like synthetic fiber. Compared with Example 1, the difference is that in step S1, polyethylene is selected as the marine polymer and xylene is selected as the organic solvent. The rest is roughly the same as in Example 1, and will not be repeated here.

[0033] Comparative Examples 1-2 Comparative Examples 1 and 2 respectively provide a pure polyester fiber and a nylon fiber, both of which are obtained by melt spinning technology. The spinning temperature of the polyester fiber is 290℃ and the spinning temperature of the nylon fiber is 280℃.

[0034] Comparative Example 3 Comparative Example 3 provides a method for preparing down-like synthetic fibers. Compared with Example 1, the difference is that polyester and cellulose acetate are directly blended and granulated, and the composite fiber is obtained by melt spinning technology. The melting temperature is 290°C, and the mass ratio of polyester to cellulose acetate is 10%:90%.

[0035] Comparative Example 4 Comparative Example 4 provides a method for preparing down-like synthetic fibers. Compared with Example 1, the difference is that in step S3, polyethylene, which is incompatible with island-phase polymers, is selected as the core layer material. The rest is roughly the same as the example, and will not be repeated here.

[0036] The down-like synthetic fibers prepared in Examples 1-3 and Comparative Examples 1-4 were used to weave fabrics, and the warmth retention and weight of the fabrics were tested. The results are shown in the table below.

[0037] Table 1. Performance characterization of fabrics prepared from down-like synthetic fibers in Examples 1-3 and Comparative Examples 1-4 As shown in Table 1, the samples prepared in Examples 1-3 exhibit good warmth retention (high Clo value) because the island phase material in the cortex is compatible with the core material. After removing the marine phase, the island phase material connects with the core material to form a fluffy structure. This fluffy structure is filled with a large amount of air, which has poor thermal conductivity. In Comparative Examples 1-2, the samples used were ordinary polyester or nylon fibers. Because these fibers are cylindrical and lack a down-like structure, the fabrics prepared from them have poor warmth retention. In Comparative Example 3, after blending and granulating polyester and cellulose acetate ester to prepare fibers, the fibers have a certain warmth retention effect, but it is still worse than that of Examples 1-3. In Comparative Example 4, polyethylene, which is incompatible with the island phase polymer, was selected as the core material. This resulted in poor connectivity between the cortex short fibers and the core backbone fibers, leading to poor spinnability of the fibers. After being spun into fabric, the nanofiber structure of the fibers deformed and weakened.

[0038] Example 4 This embodiment provides a method for preparing lightweight down-like synthetic fibers. Compared with Example 1, the difference is that in step S1, the mass percentage of island phase polymer to marine phase polymer is 30%:70%, and the rest is roughly the same as in Example 1, which will not be repeated here.

[0039] Comparative Example 5 Comparative Example 5 provides a method for preparing down-like synthetic fibers. Compared with Example 1, the difference is that in step S2, the mass percentage of island phase polymer and marine phase polymer is 50%:50%, and the rest is roughly the same as in the example, which will not be repeated here.

[0040] Comparative Example 6 Comparative Example 6 provides a method for preparing down-like synthetic fibers. Compared with Example 1, the difference is that in step S2, the mass percentage of island phase polymer to marine phase polymer is 70%:30%, and the rest is roughly the same as in the example, which will not be repeated here.

[0041] The mechanical properties and warmth retention properties of the down-like synthetic fibers prepared in Example 4 and Comparative Examples 5-6 were tested, and the results are shown in the table below.

[0042] Table 2. Performance characterization of fabrics prepared from down-like synthetic fibers in Examples 4 and Comparative Examples 5-6 As shown in Table 2, Example 4 exhibits the best warmth retention. This is because when the ratio of marine phase to island phase is 30%:70%, the island phase material forms better fiber morphology, allowing for better connection with the core layer material to form a better down structure, thus improving warmth retention. When the ratio of island phase to marine phase decreases, there is less connection between the island phase fibers and the core layer fibers, resulting in smaller pores and reduced warmth retention. When the ratio of island phase to marine phase is too high, the island phase fibers are too coarse, leading to less air filling and thus reduced warmth retention.

[0043] In summary, this invention provides a lightweight down-like synthetic fiber and its preparation method. Two-phase thermoplastic polymers are selected as marine and island phase materials, respectively. The marine and island phase materials are blended as the skin layer raw material, and a polymer compatible with the island phase polymer is used as the core layer raw material. Nascent fibers are prepared by island / skin-core melt spinning technology. The nascent fibers are then soaked in an organic solvent to remove the marine phase polymer, resulting in a lightweight down-like synthetic fiber containing core layer backbone fibers and skin layer nanofibers. The lightweight down-like synthetic fiber of this invention uses a two-phase compatible thermoplastic polymer for its core backbone fibers and sheath nanofibers. During melt spinning, the two fibers adhere to each other through molecular chain movement, resulting in a firmly bonded sheath nanofiber to the core backbone fibers, forming an integrated structure. This makes the synthetic fiber less prone to deformation, more durable, and improves the mechanical properties and practicality of the down-like fiber. Furthermore, the disordered structure of the sheath nanofibers, filled with air, makes the fiber more fluffy, and the poor thermal conductivity of air gives the fiber excellent insulation properties. This lightweight down-like synthetic fiber also contains heat-generating nanoparticles with photothermal conversion properties and antibacterial agents, giving the fiber not only good heat conversion performance under light but also excellent insulation and antibacterial effects. It is also inexpensive, has a simple manufacturing process, and broad application prospects.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing lightweight down-like synthetic fiber, characterized in that, Includes the following steps: S1. Select a thermoplastic polymer as the island phase polymer, and select a thermoplastic polymer that is incompatible with the island phase polymer as the marine phase polymer, wherein the marine phase polymer is a polymer soluble in organic solvents; S2. The island-phase polymer and the marine-phase polymer are blended and granulated to serve as the skin layer raw material, wherein the mass percentage of the island-phase polymer to the marine-phase polymer is (10%~30%):(70%~90%). S3. Select a polymer that is compatible with the island phase polymer as the core layer raw material, and prepare nascent fibers with a core-shell structure by using core-shell melt spinning technology to combine the skin layer raw material and the core layer raw material. S4. The nascent fibers obtained in step S3 are immersed in an organic solvent to remove the marine polymer from the cortex, thereby obtaining a lightweight down-like synthetic fiber. The lightweight down-like synthetic fiber comprises a core backbone fiber and a cortex nanofiber, wherein the core backbone fiber and the cortex nanofiber are an integrated structure that is mutually bonded. The diameter of the core backbone fiber is 5-15 μm, and the diameter of the cortex nanofiber is 50-800 nm, and the length is 100-5000 nm.

2. The method for preparing lightweight down-like synthetic fiber according to claim 1, characterized in that, In step S1, the island-phase polymer also contains heat-generating nanoparticles with photothermal conversion properties, wherein the particle size of the heat-generating nanoparticles is 50~500nm.

3. The method for preparing lightweight down-like synthetic fiber according to claim 1, characterized in that, In step S1, the marine polymer includes one of polystyrene, polyethylene, and cellulose acetate, and the organic solvent is selected from one of toluene, xylene, or acetone.

4. The method for preparing lightweight down-like synthetic fiber according to claim 1, characterized in that, In step S3, the melting temperature of the core-sheath melt spinning technology is higher than the melting points of the sheath material and the core material.

5. The method for preparing lightweight down-like synthetic fiber according to claim 1, characterized in that, In step S1, the thermoplastic polymer that is an island phase polymer includes one of polyester, nylon, and polyolefin.

6. The method for preparing lightweight down-like synthetic fiber according to claim 1, characterized in that, In step S3, the core layer material also contains an antibacterial agent, which is added to the core layer material during melt spinning.

7. The method for preparing lightweight down-like synthetic fiber according to claim 2, characterized in that, The heated nanoparticles include one or more of carbon powder and group IV subgroup metal carbides.

8. The method for preparing lightweight down-like synthetic fiber according to claim 6, characterized in that, The antibacterial agent includes one or more of nano-silver, nano-copper, nano-zinc, guanidine salt, and quaternary ammonium salt.

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