Method for the production of magnetic fibers and fabrics thereof

Abstract

This invention provides a method for preparing magnetic fibers and their fabrics. The method involves dissolving magnetic particles in a 20-25 wt% polyurethane mother liquor to form a 75-90 wt% magnetic particle dispersion. Then, rush fibers are immersed in the magnetic particle dispersion and subjected to vacuum curing to obtain magnetic fibers. These fibers are then woven with ordinary yarn to form a magnetic fabric, which is subsequently magnetized to obtain the magnetic fabric. By eliminating the spinning process, the rush fibers can adsorb a large number of magnetic particles, ensuring the direct and rapid construction of rush-based magnetic fibers with high magnetic field strength, good mechanical properties, and high durability. Furthermore, the rush fibers maintain their fiber shape both before and during the molding process, and the magnetic fibers used enhance the magnetism of the prepared fabric while ensuring it possesses certain mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of functional textiles, and more particularly to a method for preparing magnetic fibers and their fabrics. Background Technology

[0002] Magnetic materials, due to their excellent magnetoelectric effect, are currently widely used in electrical fields, iron ore sorting, and other areas. In recent years, with the continuous development of flexible wearable technology, the flexibility of magnetic materials has received widespread attention. Currently, commercially, soft magnets with a certain degree of magnetism are mainly prepared by using ferrite powder to prepare magnetic rubber, but the magnetism of this product is relatively weak, which limits its application. Some researchers are also using fibers or fabrics as carriers to synthesize magnetic materials on the surface of fibers to achieve magnetic functionalization of fibers or fabrics for applications in soft robots, smart materials, energy harvesting, and other fields.

[0003] The human body is not only a rich source of green energy but also a terminal for flexible intelligent wearable devices. By effectively integrating flexible energy management devices with the human body, energy generated by the body can be converted into electrical energy to power these devices, enabling them to be self-powered and solving the problem of frequent charging required by current wearable devices. To effectively harvest the high-entropy energy of the human body, energy harvesting and management systems based on thermoelectric, electromagnetic, piezoelectric, hydrovoltaic, and triboelectric effects have received widespread attention.

[0004] Patent CN113718368A discloses a method for preparing micro / nano magnetic fibers. This method involves composite materials obtained by combining magnetic particles with a substrate, and then preparing magnetic fibers with a core-shell structure through thermal stretching. Patent CN112813519A discloses a method for preparing magnetic acrylic fibers and the resulting magnetic acrylic fibers. This method uses catalysts, accelerators, and other substances to co-polymerize magnetic powder with monomers to prepare a magnetic polymer. A spinning solution is then prepared using an organic solvent, and magnetic acrylic fibers are prepared through spinning. Patent CN106400185B discloses a method for preparing magnetic cellulose composite fibers. This method involves melting cellulose lipids, preparing a magnetic dispersion through stirring, and then preparing magnetic cellulose composite fibers through extrusion, coagulation, and stretching. The invention patent with publication number CN110670162A discloses a self-generating flexible electromagnetic fiber and its preparation method and application. The method uses a polymer as a carrier and directly produces fibers of the same diameter through spinning. Regardless of whether wet or dry molding is used, the fibers will deform and form a film, which is not conducive to the spinning process.

[0005] The aforementioned patents all prepare magnetic fibers using traditional spinning methods, which involve complex processes and high technical difficulty. Furthermore, they are limited by the properties of the spinning solution and the particle size of the magnetic powder, making it impossible to achieve the goal of rapidly preparing high-performance magnetic fibers.

[0006] In view of this, it is necessary to design a method for preparing magnetic fibers and their fabrics to solve the above problems. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing magnetic fibers and their fabrics, which can be used to rapidly prepare high-performance magnetic fibers.

[0008] To achieve the above objectives, the present invention provides a method for preparing magnetic fibers, comprising the following steps:

[0009] S1. Under stirring, polyurethane is added to the organic solvent and stirred evenly to obtain a polyurethane mother liquor of a predetermined concentration.

[0010] S2. Magnetic particles of a predetermined particle size are placed in the polyurethane mother liquor and stirred to obtain a magnetic particle dispersion.

[0011] S3. According to the predetermined mass ratio, soak the rush pith fiber in the prepared magnetic particle dispersion and place it in a vacuum for a certain period of time.

[0012] S4. After vacuum treatment, the rush fibers adsorbed with the magnetic particle dispersion are solidified to obtain magnetic fibers.

[0013] Further, the predetermined concentration of the polyurethane mother liquor in step S1 is 20-25 wt%.

[0014] Further, the organic solvent mentioned in step S1 includes one of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, or toluene.

[0015] Further, the magnetic particles in step S2 include one of neodymium iron boron magnetic powder, neodymium nickel cobalt magnetic powder, ferromagnetic powder or chromium dioxide magnetic powder; the predetermined particle size of the magnetic particles is 0.001-400 μm, preferably, the predetermined particle size of the magnetic particles is 30-40 μm.

[0016] Further, the predetermined mass ratio in step S3 is: rush fiber: magnetic dispersion = 1:200; the vacuum treatment time is 1-30 min.

[0017] Further, the curing process in step S4 involves rapidly shaping the rush fiber adsorbed with the magnetic dispersion in a water bath for 3-50 minutes, followed by drying. After the curing process, the magnetic particles in the rush-based magnetic fiber account for 75-90 wt% of the total mass of the magnetic particles and the polyurethane.

[0018] The present invention also provides a method for preparing magnetic fabric using the aforementioned method for preparing magnetic fibers, comprising the following steps: firstly, weaving the magnetic fibers and ordinary yarns into an unmagnetized magnetic fabric through a weave structure; then, magnetizing the unmagnetized magnetic fabric to obtain the magnetic fabric.

[0019] Furthermore, the weave structure includes one of plain weave, twill weave, or satin weave.

[0020] Furthermore, the magnetization intensity during the magnetization process is 0.1 to 3 T.

[0021] Furthermore, the magnetization direction for the magnetization process includes either longitudinal or transverse directions.

[0022] The beneficial effects of this invention are:

[0023] 1. The present invention provides a method for preparing magnetic fibers by placing a certain amount of magnetic particles in a 20-25 wt% polyurethane mother liquor to prepare a 75-90 wt% magnetic particle dispersion, then immersing rush fibers in the specially prepared magnetic particle dispersion, followed by vacuum curing treatment to obtain magnetic fibers. Using rush fibers as a carrier, a large number of high-performance magnetic particles are loaded by adsorbing the magnetic particle dispersion, providing a guarantee for directly and rapidly constructing magnetic fabrics with high magnetic field strength, good mechanical properties, and high durability.

[0024] 2. The present invention provides a method for preparing magnetic fabrics by weaving the obtained magnetic fibers and ordinary yarns into unmagnetized magnetic fabrics, and finally performing a magnetization treatment to obtain the magnetic fabrics. Using rush fiber as a carrier allows the magnetic particle solution to maintain a circular fiber state before and during the forming process, preventing collapse and laying the foundation for the subsequent weaving of magnetic fabrics. In addition, the magnetic fabrics woven based on the magnetic fibers provided by the present invention have strong magnetic induction intensity and durability, and can therefore be used for high-entropy mechanical energy harvesting from the human body. The magnetic fabrics prepared by the present invention can also be fixed to relatively moving limbs. By moving the magnetic fabrics and induction coils relative to each other, the mechanical energy of human movement can be effectively harvested. In the experiment of rapid arm swinging of the human body, the induction coil can output a 2V voltage and a 3mA current, which can drive common wearable electronic devices and can be harvested through energy storage devices.

[0025] 3. The polyurethane mother liquor used in the method for manufacturing magnetic fibers provided by the present invention has a fast phase replacement and shaping speed when curing rush fibers adsorbed with magnetic dispersion, which can significantly improve the production efficiency of magnetic fibers. Attached Figure Description

[0026] Figure 1 This is a photograph of the magnetic fabric prepared in Example 1.

[0027] Figure 2 This is a simulation diagram of energy harvesting from magnetic fabrics, which is provided in Example 1, illustrating a method for preparing magnetic fibers and their application.

[0028] Figure 3 This is a diagram of energy harvesting from a magnetic fabric provided in Embodiment 1 of the present invention.

[0029] Figure Labels

[0030] 1-Rush-based magnetic fiber; 2-Polyester yarn; 3-Induction coil; 4-Magnetic rush fabric. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] 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.

[0034] A method for preparing magnetic fibers includes the following steps:

[0035] S1. Under stirring, add polyurethane to the organic solvent and stir evenly to obtain a polyurethane mother liquor with a concentration of 20-25 wt%.

[0036] S2. Magnetic particles with a particle size of 0.001-400μm are placed in the polyurethane mother liquor and mechanically stirred to obtain a magnetic particle dispersion.

[0037] S3. The mass ratio of rush fiber to magnetic dispersion is 1:200. The rush fiber is soaked in the prepared magnetic dispersion and then placed in a vacuum for 1-30 minutes.

[0038] S4. After vacuum treatment, the rush fibers adsorbed with the magnetic dispersion are subjected to rapid water bath shaping for 3-50 minutes, and then dried to obtain magnetic fibers; wherein, the magnetic particles in the magnetic fibers account for 75-90 wt% of the total mass of the magnetic particles and the polyurethane.

[0039] Specifically, in some embodiments of the present invention, the organic solvent in step S1 includes one of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, or toluene. The magnetic particles in step S2 include one of neodymium iron boron magnetic powder, neodymium nickel cobalt magnetic powder, ferromagnetic powder, or chromium dioxide magnetic powder; preferably, the predetermined particle size of the magnetic particles is 30-40 μm.

[0040] With this setup, using rush fiber as a carrier, a large number of high-performance magnetic particles are loaded onto the magnetic particle dispersion through adsorption, which can directly and quickly construct magnetic fibers with high magnetic field strength, good mechanical properties, and high durability.

[0041] Specifically, the present invention provides a method for preparing magnetic fabric, comprising the following steps: firstly, the magnetic fibers and ordinary yarns are woven into an unmagnetized magnetic fabric through a weave structure; then, the unmagnetized magnetic fabric is magnetized under the condition of a magnetizing machine with a magnetizing intensity of 0.1 to 3T to obtain the magnetic fabric.

[0042] This setup, using rush fiber as a carrier, allows the magnetic particle solution to maintain the rush fiber shape at all times before and during the molding process, making it easy to weave.

[0043] Specifically, in some embodiments of the present invention, the weave structure includes one of plain weave, twill weave, or satin weave. The magnetizing direction of the magnetizer includes one of longitudinal and transverse directions.

[0044] The preparation method of the magnetic fibers and their fabrics provided by the present invention will be specifically described below with reference to the embodiments:

[0045] Example 1

[0046] This embodiment provides a method for preparing magnetic fibers, which specifically includes the following steps:

[0047] A method for preparing a rush-based magnetic fiber includes the following steps:

[0048] S1. Under stirring, add 25g of polyurethane to 75g of organic solvent N,N-dimethylformamide, and stir evenly to obtain a polyurethane mother liquor with a concentration of 25wt%.

[0049] S2. Take 100g of magnetic particles with a particle size of 38μm, place them in the polyurethane mother liquor and mechanically stir to obtain a magnetic particle dispersion.

[0050] S3. Soak the rush pith fiber in the prepared magnetic dispersion at a mass ratio of 1:200, and place it in a vacuum chamber. Treat it in a vacuum environment for 10 minutes to allow the rush pith to fully adsorb the magnetic particle dispersion.

[0051] S4. After vacuum treatment, each rush fiber adsorbed with the magnetic dispersion is placed in deionized water and left to stand for 30 minutes for water bath setting. This process aims to induce phase displacement of the polyurethane in the magnetic dispersion, resulting in rapid curing and fixing of the magnetic particles within the rush fiber. After standing, the treated rush fiber is placed in an oven and dried to constant weight to obtain rush-based magnetic fiber. After water bath setting and drying, the magnetic particles in the rush-based magnetic fiber account for 80 wt% of the total mass of the magnetic particles and polyurethane. The magnetic particles loaded in the rush-based magnetic fiber account for 79% of the total mass of the rush-based magnetic fiber, magnetic particles, and polyurethane. The stress of the rush-based magnetic fiber was detected to be 2.60 MPa, and the strain was 542.36%.

[0052] This embodiment also provides a method for preparing magnetic rush fabric, which specifically includes the following steps:

[0053] like Figure 1 As shown, using 3mm diameter rush-based magnetic fibers as weft yarns and polyester as warp yarns, an unmagnetized magnetic rush fabric with a size of 5*5cm is woven through a plain weave structure; then the unmagnetized magnetic rush fabric is placed in a magnetization cavity and magnetized in a 3T instantaneous strong magnetic field, thus obtaining a magnetic rush fabric 4 with N-level upward and a magnetic field of 35.21mT.

[0054] This embodiment also provides an application of magnetic rush fabric in the preparation of a device for harvesting mechanical energy from human movement. The device includes the magnetic rush fabric and an induction coil. Specifically, the movement between the magnetic rush fabric and the induction coil includes the following two types:

[0055] Category 1

[0056] like Figure 2As shown, the induction coil 3 is a 5*5cm square with a thickness of 1cm, 2000 turns, and a wire diameter of 0.1mm. The magnetic rush fabric 4 and the induction coil 3 are placed vertically opposite each other and fixed to a reciprocating mechanism capable of relative motion, maintaining a 0mm gap. The reciprocating mechanism drives the magnetic rush fabric 4 and the induction coil 3 to move relative to each other at a speed of 1.65m / s. Under these conditions, the 2000-turn induction coil 3 can output a 1V voltage, as shown in the figure. Figure 3 As shown. Increasing the number of layers of the magnetic rush fabric 4 to 5 layers can increase the output voltage to 3V.

[0057] Category 2

[0058] The magnetic rush fabric 4 and the induction coil 3 are fixed to the limbs that can move relative to each other. The magnetic rush fabric 4 is fixed to the wrist, and the induction coil 3 is fixed to the waist. This allows the conversion of mechanical energy to electrical energy through limb movement, thus collecting high-entropy energy from human movement. To effectively utilize the collected electrical energy, a bridge rectifier circuit and an energy storage module are set up to drive common wearable devices and store energy. When a person moves, the limb movement causes the magnetic rush fabric 4 and the induction coil 3 to move relative to each other, generating alternating current (AC). The AC is converted to direct current (DC) by the bridge rectifier circuit, which can drive common wearable devices and store energy through energy storage devices such as capacitors or batteries.

[0059] The rush-based magnetic fiber prepared by this invention has good flexibility and durability. It can effectively collect mechanical energy of human movement through the law of electromagnetic induction. In simulated human movement tests, when volunteers swing their arms quickly, it can generate an AC voltage with a peak value of 2V and a current of 3mA.

[0060] Examples 2-4

[0061] Examples 2-4 respectively provide a method for preparing magnetic fibers and their fabrics, which differ from Example 1 in that:

[0062] In step S1 of Example 2, 100g of organic solvent was added under stirring, and after stirring evenly, a polyurethane mother liquor with a concentration of 20wt% was obtained.

[0063] In step S2 of Example 3, the amount of magnetic particles added is 225g.

[0064] In step S2 of Example 4, 75g of magnetic particles were added.

[0065] The remaining steps are the same as in Example 1, and will not be repeated here.

[0066] Comparative Examples 1-4

[0067] Comparative Examples 1-12 each provide a method for preparing magnetic fibers and their fabrics, which differ from Example 1 in that:

[0068] In step S1 of Comparative Example 1, the amount of organic solvent added was 141.7g.

[0069] In step S1 of Comparative Example 2, the amount of organic solvent added was 58.3g.

[0070] In step S2 of Comparative Example 3, 58.3g of magnetic particles were added.

[0071] In step S2 of Comparative Example 4, 475g of magnetic particles were added.

[0072] Comparative Example 5

[0073] Comparative Example 5 provides a method for manufacturing magnetic polyester fibers and magnetic polyester fabrics, which differs from Example 1 in that:

[0074] In step S3 of Comparative Example 5, polyester fibers were immersed in the prepared magnetic particle dispersion.

[0075] Comparative Example 6

[0076] Comparative Example 6 provides a method for manufacturing magnetic fibers, which differs from Example 1 in that:

[0077] In step S3 of Comparative Example 6, rush fiber was not used.

[0078] The remaining steps are the same as in Example 1, and will not be repeated here.

[0079] The specific parameters and experimental results are shown in Table 1.

[0080] As shown in Table 1, comparing Examples 1-2 and Comparative Examples 1-2, it was found that as the concentration of the polyurethane mother liquor increased from 15% to 25%, the proportion of magnetic particles loaded in the rush-based magnetic fibers (i.e., the proportion of magnetic particles to the total mass of polyurethane, magnetic particles, and rush fibers) remained basically unchanged, both within the range of 78% to 79%. The magnetic properties obtained using the corresponding magnetic rush fabric increased from 13.34 mT to 35.21 mT; the corresponding stress of the rush-based magnetic fibers increased from 0.27 MPa to 2.60 MPa. This indicates that polyurethane, in addition to curing the magnetic particles in rush with a high loading capacity, thereby enhancing the magnetic properties of the magnetic rush fabric, also increases the stress of the rush-based magnetic fibers. When the concentration of the polyurethane mother liquor continued to increase to 30%, although the proportion of magnetic particles loaded in the rush-based magnetic fibers remained unchanged, the magnetic properties obtained using the corresponding magnetic rush fabric decreased to 18.34 mT. This is because as the concentration of the polyurethane mother liquor increases, the number of magnetic particles fixed by the same proportion of magnetic particles also increases, thus improving the magnetism of the magnetic rush fabric. However, when the concentration of the polyurethane mother liquor is too high, the viscosity of the magnetic particle solution increases, and the rheological properties deteriorate, making it difficult for the rush fibers to fully adsorb magnetic particles, resulting in a decrease in magnetism. Comparing Examples 1, 3-4 and Comparative Examples 3-4, it was found that when the content of added magnetic particles increased from 70% to 90%, the proportion of magnetic particles loaded in the rush fibers first increased from 69% to 89%. However, when the content of magnetic particles was further increased to 95%, the entire experimental process was almost impossible to stir normally due to the excessively high viscosity, so the corresponding product could not be obtained. Comparing Examples 1 and Comparative Examples 5-6, it can be seen that if polyester fibers are used to replace the rush fibers used in this application, the number of magnetic particles loaded on the fibers will decrease, thereby affecting the magnetism of the subsequent fabric. While the stress of the magnetic polymer fibers prepared using only polyurethane is comparable to that of the magnetic rush fabric, the resulting magnetic effect is not as good as that provided by this invention. Therefore, by preparing a 75-90 wt% magnetic particle dispersion in 20-25 wt% polyurethane mother liquor, and then immersing the rush fibers in this specially prepared magnetic particle dispersion, followed by water bath setting and drying within 3-50 minutes, the loading of magnetic particles in the rush-based magnetic fibers can be increased, thus obtaining rush-based magnetic fibers with higher magnetic properties.

[0081] Table 1 Experimental parameters and results

[0082]

[0083] In summary, this invention provides a method for preparing magnetic fibers and their fabrics. A certain amount of magnetic particles is placed in a 20-25 wt% polyurethane mother liquor to prepare a 75-90 wt% magnetic particle dispersion. Then, rush fibers are immersed in this specially prepared magnetic particle dispersion, followed by vacuum curing to obtain the magnetic fibers. Using rush fibers as a carrier, a large number of high-performance magnetic particles are loaded by adsorbing the magnetic particle dispersion. This eliminates the need for spinning and allows for the loading of even more magnetic particles, ensuring the direct and rapid construction of magnetic fibers with high magnetic field strength, good mechanical properties, and high durability. The obtained magnetic fibers are woven with ordinary yarn into an unmagnetized magnetic fabric, which is then magnetized to obtain the final magnetic fabric. Using rush fibers as a carrier allows the magnetic particle solution to maintain the fiber shape of the rush fibers before and during molding, and the magnetic fibers also enhance the magnetic and mechanical properties of the prepared fabric. Furthermore, the magnetic fabric woven from the magnetic fibers provided by this invention possesses strong magnetic induction and durability, making it suitable for harvesting high-entropy mechanical energy from the human body. The magnetic fabric prepared by this invention can also be fixed to a relatively moving limb; the movement of the fabric and the induction coil enables effective harvesting of mechanical energy from human movement. During experiments involving rapid arm swinging, the induction coil can output a 2V voltage and a 3mA current, capable of driving common wearable electronic devices and being harvested through energy storage devices. Moreover, the polyurethane mother liquor used allows for rapid phase replacement and shaping when the rush fiber containing the magnetic dispersion of the polyurethane mother liquor is subjected to water bath and drying treatment, significantly improving the production efficiency of the magnetic fiber.

[0084] 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 magnetic fibers, characterized in that, Includes the following steps: S1. Under stirring, polyurethane is added to the organic solvent and stirred until homogeneous to obtain a polyurethane mother liquor of a predetermined concentration; the predetermined concentration of the polyurethane mother liquor is 20-25 wt%. S2. Magnetic particles of a predetermined particle size are placed in the polyurethane mother liquor and stirred to obtain a magnetic particle dispersion; the predetermined particle size of the magnetic particles is 0.001-400 μm. S3. According to the predetermined mass ratio, soak the rush pith fiber in the prepared magnetic particle dispersion and place it in a vacuum for a certain period of time. S4. After vacuum treatment, the rush fiber adsorbed with the magnetic particle dispersion is cured to obtain magnetic fiber. The curing process involves water bath shaping of the rush fiber adsorbed with the magnetic dispersion for 3-50 minutes, followed by drying. After the curing process, the magnetic particles in the rush-based magnetic fiber account for 75-90 wt% of the total mass of the magnetic particles and the polyurethane.

2. The method for preparing magnetic fibers according to claim 1, characterized in that: The organic solvent mentioned in step S1 includes one of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, or toluene.

3. The method for preparing magnetic fibers according to claim 1, characterized in that: The magnetic particles mentioned in step S2 include one of neodymium iron boron magnetic powder, neodymium nickel cobalt magnetic powder, ferromagnetic powder or chromium dioxide magnetic powder.

4. The method for preparing magnetic fibers according to claim 1, characterized in that: The predetermined particle size of the magnetic particles is 30-40 μm.

5. The method for preparing magnetic fibers according to claim 1, characterized in that: The predetermined mass ratio in step S3 is: rush pith fiber: magnetic dispersion = 1:200; the vacuum treatment time is 1-30 min.

6. A method for preparing a magnetic fabric, characterized in that, Includes the following steps: First, the magnetic fibers and ordinary yarn prepared by the method described in any one of claims 1 to 5 are woven into an unmagnetized magnetic fabric through a weave structure; then, the unmagnetized magnetic fabric is magnetized to obtain the magnetic fabric.

7. The method for preparing magnetic fabric according to claim 6, characterized in that: The weave structure includes one of plain weave, twill weave, or satin weave.

8. The method for preparing magnetic fabric according to claim 6, characterized in that: The magnetization intensity during the magnetization process is 0.1~3T.

9. The method for preparing magnetic fabric according to claim 8, characterized in that: The magnetization direction for the magnetization process includes either longitudinal or transverse.

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