A mechanical reinforcement method and apparatus for micro-nano-scale welding of ultrafine fiber materials

Abstract

This invention relates to a method and apparatus for mechanical enhancement through micro-nano-scale welding of ultrafine fiber materials. The method involves directional welding at the submicron scale between ultrafine fibers to obtain ultrafine fiber materials with submicron-scale bonding points. Utilizing the interaction of these submicron-scale bonding points, ultrafine fiber materials with enhanced mechanical properties are obtained. The apparatus includes a spinning system, a micro-nano welding system, and a winding system. The spinning system is used to spin ultrafine fiber materials, the micro-nano welding system is used to form submicron-scale bonding points between the ultrafine fibers, which can significantly enhance the mechanical properties of the ultrafine fiber materials, and the winding system is used to wind and receive the mechanically enhanced ultrafine fiber materials. Compared with existing technologies, the ultrafine fiber materials prepared by this invention improve all mechanical properties while maintaining the original structure. The tensile strength of the ultrafine fiber membrane is increased to over 12 MPa, and the compression resilience of the ultrafine fiber flakes is increased to over 90%.

Description

Technical Field

[0001] This invention relates to the field of fiber materials technology, and in particular to a method and apparatus for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber materials. Background Technology

[0002] Microfibers, as a new generation of synthetic fibers, typically have a diameter of less than 5 μm, thus possessing characteristics such as a large aspect ratio, high specific surface area, and strong structural adjustability. Membranes or flake materials prepared from microfibers exhibit small pore size, high porosity, and excellent pore connectivity, making them highly promising for applications in filtration, lightweight insulation, sound absorption and noise reduction, and high-temperature insulation. However, the extremely small diameter of microfibers and the loose, slipping inter-fiber structure result in poor pore stability, weak shear resistance, and low tensile strength in their products. These issues reduce the service life of the materials and limit their further expansion into various application areas. Therefore, enhancing the mechanical properties of microfiber materials has become an urgent problem to be solved in the fiber manufacturing field.

[0003] To address the aforementioned issues, researchers have already conducted relevant studies in this field. In the manufacture of high-strength polymer fiber membrane materials, patent 202311161572.3 involves re-immersing the prepared fiber membrane material in a solvent (or fumigating it in a solvent atmosphere) to induce micro-dissolution on the fiber surface, thereby ensuring initial adhesion between the fibers. The initially adhered fiber membrane is then subjected to hot rolling, resulting in a tighter bonded structure and preventing fiber membrane delamination. However, this method uses a solvent to dissolve the fibers and then employs a hot rolling process to complete the bonded structure, which can lead to large-area adhesion and even melting film phenomena, damaging the structural integrity and performance of the fiber membrane. Patent 201910675001.9 describes immersing a drug-releasing membrane prepared by electrospinning in an ultraviolet crosslinking agent and then crosslinking the fiber membrane under ultraviolet light. This process uses an immersion method to coat the ultraviolet crosslinking agent, which, under surface tension, forms a reagent film between the fibers. After curing, this film forms a closed-cell structure, damaging the performance of the fiber membrane. Furthermore, immersion treatment results in significant reagent waste. In the manufacture of high-strength fiber wadding materials, patent 202110662354.2 describes adding a low-melting-point skeleton fiber to rabbit hair fibers and preparing a three-dimensional insulating wadding using a web-laying technique. This wadding is then baked in a large oven and hot-rolled to bond the skeleton fiber to the rabbit hair fibers, improving the mechanical properties of the fiber wadding. However, the hot-rolling process in this method causes large-area adhesion between skeleton fibers and between skeleton fibers and rabbit hair fibers, reducing the bulkiness and insulation performance of the fiber wadding.

[0004] Therefore, designing a non-destructive, high-strength mechanical reinforcement method to prepare ultrafine fiber materials with high mechanical properties is the key to the continued development of this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the limitations of existing technologies in preparing ultrafine fiber materials that simultaneously achieve both non-damaging and high strength by providing a mechanical reinforcement method and apparatus for micro-nano-scale welding of ultrafine fiber materials.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a mechanical enhancement method for micro-nano-scale welding of ultrafine fiber materials. The method involves performing submicron-scale directional welding between ultrafine fibers to obtain ultrafine fiber materials with submicron-scale bonding points. By utilizing the interaction of the submicron-scale bonding points, an ultrafine fiber material with enhanced mechanical properties is obtained.

[0008] In some specific embodiments, the microfiber material includes a microfiber membrane or microfiber flakes. When the microfiber material is a microfiber membrane, the method for enhancing the mechanical properties of the microfiber membrane includes the following steps:

[0009] S1-1. Micro-point hot rolling reaction is performed on the ultrafine fiber membrane material to form an ultrafine fiber membrane with micron-level fusion bonding points;

[0010] S1-2. The ultrafine fiber membrane with micron-level fusion bonding points obtained in step S1-1 is subjected to ultraviolet irradiation, which causes nanoscale cross-linking to form between fiber intersections, forming a welding structure at the micro / nano scale, and obtaining an ultrafine fiber membrane with enhanced mechanical properties.

[0011] When the ultrafine fiber material is an ultrafine fiber sheet, the method for enhancing the mechanical properties of the ultrafine fiber sheet includes the following steps:

[0012] S2-1. Under the traction of negative pressure and electrostatic force, micron-sized sol particles are attached to the ultrafine fiber flocs, and under capillary action, the micron-sized sol particles are directionally transferred to the fiber overlap to form ultrafine fiber flocs with sol coating points.

[0013] S2-2. The ultrafine fiber flocs obtained in step S2-1, which have sol-coated points at the fiber overlaps, are heated to form a micro-nano scale welded structure, resulting in ultrafine fiber flocs with enhanced mechanical properties.

[0014] In some specific embodiments, in step S1-1, the ultrafine fiber membrane material is an ultrafine organic polymer fiber membrane material, which is selected from any one or more of the following ultrafine organic polymer fiber membrane materials: polyurethane, polyethylene oxide, polyamide, polyvinyl chloride, polyvinylidene fluoride, polycarbonate, aramid 1313, polymethyl methacrylate, polyimide, polystyrene, polybenzimidazole, polyethylene terephthalate, polycaprolactone, polylactic acid, polyhydroxybutyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polysulfone, polyethyleneimine, polyimide, polypropylene glycol terephthalate, or polyvinyl butyral fiber.

[0015] The raw materials used in the ultrafine fiber membrane material include low-melting-point elastic oligomers, photoreactive reagents, and spinning solutions, wherein:

[0016] The low-melting-point elastic oligomer is selected from any one or more of thermoplastic polyurethane elastomers, polyolefin elastomers, dynamically vulcanized polyolefin elastomers, polystyrene elastomers, polyether ester elastomers, or polyamide elastomers, and the final concentration of the low-melting-point elastic oligomer in the raw material is 0.5 to 8 wt%.

[0017] The photoreaction reagent includes a photoinitiator and a photocrosslinking agent. The photoinitiator is selected from any one or more of TPO (diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide), TPO-L (ethyl 2,4,6-trimethylbenzoylphenylphosphonate), 907 initiator, ITX (2-isopropylthioxanthone), 184 initiator, 1173 initiator, BDK (benzoin dimethyl ether), OMBB (methyl 2-o-benzoylbenzoate), BP (benzophenone), CBP (4-chlorobenzophenone), PBZ (biphenyl benzophenone), 369 initiator, 819 initiator, 754 initiator, 127 initiator, 784 initiator, or TMO (2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide).

[0018] The photocrosslinking agent is selected from any one or more of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylolpropane trimethacrylate, N,N-methyleneacrylamide, or epichlorohydrin.

[0019] The final concentration of the photoinitiator in the raw material is 0.3-3 wt%, and the final concentration of the photocrosslinker in the raw material is 0.5-5 wt%.

[0020] In some specific embodiments, the spinning solution of the ultrafine organic polymer fiber membrane material mainly consists of 10-60 wt% organic polymer and solvent. The organic polymer is selected from one or more of polyurethane, polyethylene oxide, polyamide, polyvinyl chloride, polyvinylidene fluoride, polycarbonate, aramid 1313, polymethyl methacrylate, polyimide, polystyrene, polybenzimidazole, polyethylene terephthalate, polycaprolactone, polylactic acid, polyhydroxybutyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polysulfone, polyethyleneimine, polyimide, polypropylene glycol terephthalate, or polyvinyl butyral. The solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, acetic acid, dimethyl sulfoxide, toluene, acetone, cyclohexane, isobutanol, dichloromethane, butyl acetate, ethyl acetate, or chloroform.

[0021] In some specific embodiments, in step S1-1, the method of micro-point hot rolling reaction is as follows: using small-sized rigid rolling points with a diameter of 1 to 30 μm, hot rolling temperature of 100 to 350°C, loading pressure of 2 to 8 MPa, and hot pressing time of 2 to 10 s.

[0022] More preferably, the material of the small-sized rigid rolling point is selected from any one of silicon carbide, brown fused alumina, white fused alumina, and diamond.

[0023] In some specific embodiments, in step S1-2, the ultraviolet wavelength during ultraviolet irradiation is 365-405nm, and the irradiation intensity is 500-3000mW.

[0024] In some specific embodiments, in step S2-1, the ultrafine fiber floc material is an ultrafine organic polymer fiber floc material or an ultrafine inorganic fiber floc material, wherein:

[0025] The ultrafine organic polymer fiber flocs are selected from any one or more of the following ultrafine organic polymer fiber flocs: polyurethane, polyethylene oxide, polyamide, polyvinyl chloride, polyvinylidene fluoride, polycarbonate, aramid 1313, polymethyl methacrylate, polyimide, polystyrene, polybenzimidazole, polyethylene terephthalate, polycaprolactone, polylactic acid, polyhydroxybutyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polysulfone, polyethyleneimine, polyimide, polypropylene glycol terephthalate, or polyvinyl butyral fiber.

[0026] The ultrafine inorganic fiber flocs are selected from any one or more of the following: silicon dioxide, aluminum oxide, zirconium oxide, titanium dioxide, and mullite fiber.

[0027] The micron-sized sol particles are selected from any one of styrene, acrylic acid, vinyl acetate-acrylic acid, styrene-vinyl acetate, vinyl acetate-tert-carbonic acid-acrylic acid, natural rubber, environmentally friendly resin, silica sol, aluminum sol, zirconium sol, titanium sol, silica-alumina sol, or silica-zirconium sol, with a solid content of 20-60 wt% and a diameter of 1-10 μm.

[0028] In some specific embodiments, the spinning solution of the ultrafine organic polymer fiber wadding material mainly consists of 10-60 wt% organic polymer and solvent. The organic polymer is selected from any one or more of polyurethane, polyethylene oxide, polyamide, polyvinyl chloride, polyvinylidene fluoride, polycarbonate, aramid 1313, polymethyl methacrylate, polyimide, polystyrene, polybenzimidazole, polyethylene terephthalate, polycaprolactone, polylactic acid, polyhydroxybutyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polysulfone, polyethyleneimine, polyimide, polypropylene glycol terephthalate, or polyvinyl butyral. The solvent is selected from any one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, acetic acid, dimethyl sulfoxide, toluene, acetone, cyclohexane, isobutanol, dichloromethane, butyl acetate, ethyl acetate, or chloroform.

[0029] In some specific embodiments, the spinning solution of the ultrafine inorganic fiber flocculent material is mainly composed of 40-70 wt% inorganic raw materials and solvents. The inorganic raw materials are selected from any one or more of the following: tetraethyl orthosilicate, tetra-n-butoxysilane, tetra-n-propoxysilane, trimethylsilyl acetate, vinyltriethoxysilane, titanium tetramethanol, titanium tetraethanol, titanium n-propoxide, titanium isopropoxide, titanium n-butoxide, titanium isobutoxide, titanium tert-butoxide, titanium tetrapentoxide, titanium isooctanol, zirconium tetramethanol, zirconium tetraethanol, zirconium n-propoxide, zirconium isopropoxide, zirconium n-butoxide, zirconium isobutoxide, zirconium tert-butoxide, zirconium tetrapentoxide, aluminum trimethoxy, aluminum triethanoloxide, aluminum tri-n-propoxy, aluminum isopropoxide, aluminum n-butoxide, aluminum sec-butoxide, or aluminum tert-butoxide. The solvent is selected from any one or more of ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, ethylene glycol, butanediol, hexanediol, glycerol, acetic acid, and water.

[0030] More preferably, when the ultrafine fiber flocs are ultrafine organic polymer fiber flocs, the sol particles are selected from any one of acrylic acid, styrene, vinyl acetate-acrylic acid, styrene-vinyl acetate, vinyl acetate-tert-carbonic acid-acrylic acid, natural rubber or environmentally friendly resin, and their solid content is 20-50 wt%.

[0031] When the ultrafine fiber flocs are ultrafine inorganic fiber flocs, the sol particles are selected from any one of silica sol, aluminum sol, zirconium sol, titanium sol, silica-alumina sol, or silica-zirconium sol, and their solid content is 40-60 wt%.

[0032] In some specific embodiments, in step S2-2, the heating method is microwave-assisted heating, with a temperature of 20–800°C and a frequency of 3000–300000MHz. Microwave-assisted heating allows microwaves to penetrate deep into the material and rapidly heat small molecules, forming a submicro-scale welded structure.

[0033] The second technical solution of the present invention provides a mechanical reinforcement device for micro-nano-scale welding of ultrafine fiber materials, used to implement the mechanical reinforcement method for micro-nano-scale welding of ultrafine fiber materials as described in one of the above technical solutions, comprising:

[0034] Spinning systems are used to spin ultrafine fiber materials;

[0035] A micro-nano welding system is used to form ultrafine fiber materials with submicron scale bonding points, and react the submicron scale bonding points to obtain ultrafine fiber materials with enhanced mechanical properties.

[0036] A winding system for winding and receiving the mechanically enhanced microfiber material.

[0037] In some specific embodiments, the spinning system employs any one of electrostatic air-jet spinning, solution electrospinning, or melt electrospinning.

[0038] In some specific embodiments, the spinning system includes a spinneret for receiving spinning raw materials, a spinning nozzle disposed at the bottom of the spinneret for spinning, an auxiliary component disposed at the bottom of the spinning nozzle for forming, and a receiving belt for receiving and transmitting ultrafine fiber material flowing out through the auxiliary component. The spinning nozzle is also connected to a first high-voltage static power supply.

[0039] In some specific embodiments, the microfiber material includes a microfiber membrane or microfiber flakes.

[0040] When the ultrafine fiber material is an ultrafine fiber membrane, the micro-nano welding system includes a plurality of first transmission belts located downstream of the spinning system for transporting the ultrafine fiber membrane, a rigid hot rolling roll assembly located between two of the first transmission belts for micro-point hot rolling, and an ultraviolet beam-gathering assembly located downstream of the rigid hot rolling roll assembly for ultraviolet irradiation.

[0041] When the ultrafine fiber material is an ultrafine fiber flake, the micro-nano welding system includes a sol coating component located downstream of the spinning system for releasing sol particles, and a microwave-assisted heating component located upstream of the sol coating component for heating.

[0042] In some specific embodiments, the rigid hot rolling roll assembly includes an upper roll and a lower roll, wherein the surface of the upper roll is provided with regularly arranged rigid rolling points, and the surface of the lower roll is a smooth rigid roll.

[0043] The diameter of the rigid rolling point is 1 to 30 μm, and the material of the rigid rolling point is selected from any one of silicon carbide, brown fused alumina, white fused alumina, and diamond.

[0044] More preferably, the material of the lower roll is selected from any one of silicon carbide, tungsten carbide, tungsten carbide-titanium carbide-cobalt, and tungsten carbide-titanium carbide-tantalum carbide-cobalt.

[0045] In some specific embodiments, the ultraviolet beam-gathering assembly includes an ultraviolet emitter, a concave mirror and a convex mirror sequentially disposed below the ultraviolet emitter.

[0046] In some specific embodiments, the sol-coating assembly includes a second conveyor belt located downstream of the spinning system for transporting the microfiber flocculations, a semi-enclosed housing, a spray assembly located inside the semi-enclosed housing and respectively positioned above and below the microfiber flocculations, and a dense dot matrix suction assembly.

[0047] The spray assembly is used to spray sol to form sol particles, and includes a spray generator, a second high-voltage static power supply, and a plurality of atomizing nozzles connected to the spray generator and the second high-voltage power supply.

[0048] The dense dot matrix suction assembly is used to disperse the sol particles inside the fiber flocs, and includes a fractal flow channel plate, suction micropores provided on the fractal flow channel plate, and a vacuum pump connected to the fractal flow channel plate through an air pipe.

[0049] In some specific embodiments, the microwave-assisted heating assembly includes a third conveyor belt that abuts against the second transmission belt, a heat insulation shell, a microwave generator and a heating roller disposed inside the heat insulation shell and respectively disposed above and below the microfiber wadding, and the top of the heat insulation shell is also provided with an air outlet.

[0050] The technical principle of this invention is as follows:

[0051] This invention enhances the mechanical strength of ultrafine fiber materials by precisely orienting them to obtain submicron-scale bonding points, and then by reacting with these submicron-scale bonding points.

[0052] For microfiber membrane materials, this invention pre-embeds low-melting-point elastic oligomers and photoreactive reagents inside the microfiber membrane. When the microfiber membrane passes through rigid hot rolling mills, the low-melting-point elastic oligomers melt at high temperatures. At this time, under the pressure of the ultra-small rigid rolling mills, they form extremely small bonding points, avoiding large-area adhesion of the microfiber membrane. Under subsequent high-intensity ultraviolet light irradiation, the ultraviolet crosslinking reagent undergoes a photochemical reaction on the surface of the polymer fibers, generating covalent bonds, thereby causing crosslinking and curing of the fiber cross-points at the micro / nano scale, further enhancing the mechanical properties of the microfiber membrane material.

[0053] To enhance the mechanical properties of microfiber membranes, this invention primarily involves hot-pressing the fiber membrane with ultra-small rigid rolling points, resulting in physical bonding points at the submicron scale. This process avoids large-area melting film phenomena, ensuring the porous structure and flexibility of the fiber membrane. Furthermore, ultraviolet chemical crosslinking further increases micro-nano-scale welding points between fibers, forming a multi-level bridging structure of physical adhesion and chemical crosslinking. This structure can disperse stress at different scales, effectively improving the tensile properties of the fiber membrane material.

[0054] For ultrafine fiber floc materials, this invention transports the prepared loose ultrafine fiber flocs into a sol-coating component filled with uniformly dispersed micron-sized sol particles. Under the traction of negative pressure and electrostatic action, the sol particles diffuse uniformly into the interior of the ultrafine fiber flocs and adhere to the fibers. At this time, under the capillary action formed by the fiber overlap, the sol particles gradually extend directionally to the fiber overlap point and form sol-coating points under the drive of the surface tension of the sol particles. After the ultrafine fiber flocs are transferred to a microwave-assisted heating component, the microwaves perform high-frequency heating on the water molecules in the sol-coating points, disrupting the stable state inside the sol-coating points, thereby causing the sol-coating points to rapidly lose water and solidify. The welding of the ultrafine fiber flocs is completed at the micro-nano scale, which greatly improves the mechanical properties of the ultrafine fiber floc materials.

[0055] Regarding enhancing the mechanical properties of microfiber wadding, this invention mainly involves coating sol-particles at the fiber overlap points and forming robust micro-nano welding points under high temperature, thereby creating a bridging structure between fibers. This allows tensile force to be efficiently distributed across each fiber, thus increasing the tensile properties of the fiber wadding.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The mechanical properties of the ultrafine fiber materials prepared by the present invention are significantly and effectively improved. Among them, the ultrafine fiber membrane material forms extremely small physical bonding points under the rolling of ultrafine rigid rolling points, and a large number of chemical cross-linking points occur between the fibers. Through the combined effect of physical and chemical cross-linking, the mechanical properties of the ultrafine fiber membrane material are improved to the maximum extent without damaging the fiber membrane material. Compared with the unreinforced fiber membrane, the tensile strength of the ultrafine fiber membrane prepared by the present invention is increased to more than 12 MPa.

[0058] The ultrafine fiber wadding material is oriented to form stable and high-strength weld points at the fiber overlap points, which maximizes the material's compression and tensile properties without damaging the porous structure of the fiber wadding; compared with unwelded fiber wadding, its tensile breaking strength is increased to over 0.3 MPa.

[0059] (2) The ultrafine fiber floc material prepared by the present invention also has excellent compression recovery rate and bulkiness. The compression recovery rate of the ultrafine fiber floc material is increased to more than 90%, and the ultrafine fiber membrane material prepared also has excellent porosity and elastic recovery rate.

[0060] (3) The present invention also provides a micro-nano welding device for mechanical reinforcement of ultrafine fiber materials, which is easy to operate, highly versatile and widely applicable. Attached Figure Description

[0061] Figure 1 This is a roadmap for micro / nano welding technology used for mechanical reinforcement of ultrafine fiber materials.

[0062] Figure 2 This is a schematic diagram of the spinning system.

[0063] Figure 3 This is a schematic diagram of a micro / nano welding system used to prepare ultrafine fiber membrane materials with enhanced mechanical properties.

[0064] Figure 4 for Figure 3 A schematic diagram of the structure of a medium-rigidity hot rolling roll assembly.

[0065] Figure 5 for Figure 3 A schematic diagram of the structure of the mid-ultraviolet beam-gathering component.

[0066] Figure 6 This is a schematic diagram of a micro / nano welding system used to prepare ultrafine fiber floc materials with enhanced mechanical properties.

[0067] Figure 7 for Figure 6 A schematic diagram of the structure of the sol-coated component.

[0068] Figure 8 for Figure 7 A schematic diagram of the structure of the central spray assembly.

[0069] Figure 9 for Figure 7 A schematic diagram of the structure of a medium-dense dot matrix suction assembly.

[0070] Figure 10 for Figure 6 A schematic diagram of the structure of the microwave heating component.

[0071] The diagram is labeled as follows:

[0072] 11 is a spinneret, 12 is a spinning nozzle, 13 is an auxiliary component, 14 is the first high-voltage static power supply, 15 is a receiving belt, and 16 is a microfiber material.

[0073] 21 is a rigid hot rolling roll assembly, 211 is an upper rolling roll, 212 is a lower rolling roll, 213 is a rigid rolling point, 22 is an ultraviolet beam assembly, 221 is an ultraviolet emitter, 222 is a concave mirror, 223 is a convex mirror, 224 is an ultraviolet beam, 23 is the first transmission belt, and 24 is a microfiber membrane with enhanced mechanical properties.

[0074] 3 is a sol coating component, 31 is a spray component, 311 is a second high-voltage static power supply, 312 is a spray generator, 313 is an atomizing nozzle, 314 is a semi-enclosed shell, 32 is a dense dot matrix suction component, 321 is a fractal flow channel plate, 322 is a vacuum pump, 323 is an air pipe, 324 is a suction micropore, and 33 is a second conveyor belt.

[0075] 4 is a microwave-assisted heating component, 41 is a microwave generator, 42 is a heating roller, 43 is a third conveyor belt, 44 is an air outlet, 45 is a heat-insulating shell, and 46 is a microfiber wadding with enhanced mechanical properties. Detailed Implementation

[0076] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0077] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art. Unless otherwise specified, the functional components or structures are conventional components or conventional structures used in the art to achieve the corresponding functions.

[0078] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0079] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0080] Example 1:

[0081] like Figure 1 As shown, this embodiment provides a mechanical reinforcement device for micro-nano-scale welding of ultrafine fiber materials, comprising:

[0082] Spinning systems are used to spin ultrafine fiber materials;

[0083] A micro-nano welding system is used to form ultrafine fiber materials with submicron scale bonding points, and react the submicron scale bonding points to obtain ultrafine fiber materials with enhanced mechanical properties.

[0084] A winding system for winding and receiving the mechanically enhanced microfiber material.

[0085] In this embodiment, the microfiber material is oriented to obtain submicron-scale bonding points, and these submicron-scale bonding points are used to enhance the mechanical strength of the microfiber material.

[0086] like Figure 2 As shown, the spinning system can employ any one of electrostatic air-jet spinning, solution electrostatic spinning, or melt electrostatic spinning. For example, the spinning system can include a spinneret 11 for receiving the spinning raw material, a spinning nozzle 12 located at the bottom of the spinneret 11 for spinning, auxiliary components 13 located at the bottom of the spinning nozzle 12 for forming (e.g., heater, air inlet assembly), and a receiving belt 15 for receiving and transmitting the microfiber material 16 flowing out through the auxiliary components 13. The spinning nozzle 12 is also connected to a first high-voltage electrostatic power supply 14. The spinning raw material flows through the spinneret 11 and, under the action of electrostatic force or the stretching force of electrostatic force and airflow, forms microfiber material 16, such as a microfiber membrane or microfiber flakes, which is then received on the receiving belt 15. By adjusting the spinning parameters and combining the auxiliary components 13, microfiber materials with different structures and thicknesses, such as microfiber membranes or microfiber flakes, can be obtained.

[0087] Example 2:

[0088] Based on the spinning system and winding system provided in Example 1, such as Figure 3As shown, this embodiment specifically provides a micro-nano welding system for enhancing the mechanical properties of microfiber membranes. The micro-nano welding system includes several first transmission belts 23 sequentially connected to the receiving belt 15 and for transporting the microfiber membrane; a rigid hot rolling roll assembly 21 disposed between two of the first transmission belts 23 for micro-point hot rolling; and an ultraviolet (UV) beam-gathering assembly 22 disposed above the transmission belts 23 for UV irradiation. Through directional micro-point hot rolling physical adhesion via the rigid hot rolling roll assembly 21, combined with UV chemical cross-linking by the UV beam-gathering assembly 22, the original porous structure and flexibility of the fiber membrane are maintained while further increasing the number of micro-nano-scale welding points, forming a multi-level bridging structure. This structure can disperse stress at different scales, effectively improving the mechanical properties of the fiber membrane, such as tensile properties.

[0089] like Figure 4 As shown, in this embodiment, the rigid hot rolling roll assembly 21 includes an upper roll 211 and a lower roll 212. The upper roll 211 has regularly arranged rigid points 213 on its surface, and the lower roll 212 is a smooth, rigid roll. The diameter of the rigid points 213 is 1–30 μm, and the material of the rigid points is selected from any one of silicon carbide, brown fused alumina, white fused alumina, and diamond. The material of the lower roll 212 is selected from any one of silicon carbide, tungsten carbide, tungsten carbide-titanium carbide-cobalt, and tungsten carbide-titanium carbide-tantalum carbide-cobalt. When the upper roll 211 and the lower roll 212 are used to weld the ultrafine fiber membrane, the rigid points 213 on the upper roll 211 will not make elastic contact with the lower roll 212, reducing the physical cross-linking points on the surface of the fiber membrane and avoiding large-area adhesion.

[0090] like Figure 5 As shown, in this embodiment, the ultraviolet beam-gathering assembly 22 includes an ultraviolet emitter 221, a concave mirror 222, and a convex mirror 223 sequentially disposed below the ultraviolet emitter 221. The ultraviolet light generated by the ultraviolet emitter 221 is beamed into an ultraviolet beam 224 perpendicular to the fiber membrane's running direction by the beam-gathering effect of the concave mirror 222 and the convex mirror 223, increasing the ultraviolet radiation intensity and significantly improving the crosslinking reaction efficiency, thus preparing an ultrafine fiber membrane 24 with enhanced mechanical properties. For example, the light source of the ultraviolet emitter 221 is set as a linear light source, which is practical and easy to control.

[0091] Example 3:

[0092] Based on the spinning system and winding system provided in Example 1, such as Figure 6As shown, this embodiment specifically provides a micro-nano welding system for enhancing the mechanical properties of ultrafine fiber wadding. The micro-nano welding system includes a second conveyor belt 33 connected in sequence with the receiving belt 15 and for transporting the ultrafine fiber wadding, a sol coating component 3 for releasing micron-sized sol particles, and a microwave-assisted heating component 4 for heating. The sol coating component 3 directionally forms sol coating points at the fiber overlaps, and under the high temperature of the microwave-assisted heating component 4, strong micro-nano welding points are formed. Because an interconnected bridging structure is formed between the fibers, the tensile force can be efficiently distributed on each fiber, thereby increasing the mechanical properties of the fiber wadding, such as tensile strength.

[0093] like Figure 7-9 As shown, in this embodiment, the sol coating component 3 includes a semi-enclosed shell 314 with open inlet and outlet, a spray component 31 disposed within the semi-enclosed shell 314 and respectively disposed above and below the ultrafine fiber flocs, and a dense dot matrix suction component 32. The spray component 31 is used to spray sol to form micron-sized sol particles, and includes a spray generator 312, a second high-voltage static power supply 311, and a plurality of atomizing nozzles 313 connected to the spray generator 312 and the second high-voltage static power supply 311. The exemplary spray generator 312 can be an electrostatic or ultrasonic sprayer. The dense dot matrix suction component 32 is used to disperse the micron-sized sol particles inside the ultrafine fiber flocs, and includes a fractal flow channel plate 321, suction micropores 324 disposed on the fractal flow channel plate 321, and a vacuum pump 322 connected to the fractal flow channel plate 321 through an air pipe 323. The voltage of the second high-voltage static power supply 311 is set to 1–10 kV, and the operating frequency of the spray generator 312 is set to 10–100 kHz. Under the combined action of the electrostatic / ultrasonic sprayer and the high static voltage, the sol forms ultrafine micron-sized sol particles with a diameter of 1–10 μm. After the vacuum pump 322 of the dense lattice suction assembly 32 is started, the pumping speed of the vacuum pump 322 is set to 0.5–2 m / s². 3 / h, the gas enters the fractal flow channel plate 321 uniformly from the suction micropores 324, and the negative pressure formed can uniformly disperse the sol particles into the interior of the ultrafine fiber flocs.

[0094] like Figure 10As shown, in this embodiment, the microwave-assisted heating assembly 4 includes a third conveyor belt 43 that abuts against the second transmission belt 33, a heat-insulating shell 45, a microwave generator 41 and a heating roller 42 disposed inside the heat-insulating shell 45 and respectively positioned above and below the microfiber flocs. The top of the heat-insulating shell 45 is also provided with an air outlet 44. Under the action of the electromagnetic waves generated by the microwave generator 41, the sol-coated points on the microfiber flocs rapidly lose water and become disordered, and under the heat radiation of the heating roller 42, quickly form stable and strong welding points, enhancing the mechanical strength of the microfiber flocs and producing a microfiber floc 46 with enhanced mechanical properties.

[0095] The microwave heating component 4 is not limited to the curing of sol-coated points on ultrafine fiber flocs; it can also be used for the rapid calcination of ceramic fiber membranes or floc materials. By adjusting the emission frequency of the microwave generator 41, the small molecular chains within the fiber undergo pre-fracture due to high-frequency vibration and are rapidly removed under the high temperature generated by the heating roller 42. This process can produce flexible ceramic ultrafine fiber materials with small grains and multi-grain boundary structures.

[0096] Example 4:

[0097] Using the apparatus provided in Examples 1 and 2, this embodiment provides a method for mechanical reinforcement of micro / nano-scale welding of ultrafine fiber membranes, comprising the following steps:

[0098] (1) Thermoplastic polyurethane elastomer, TOP initiator and ethylene glycol dimethacrylate monomer were added to polyurethane organic polymer spinning solution (solvent was N,N-dimethylformamide) and mixed evenly to prepare spinning solutions with elastomer, initiator, reactive monomer and polymer concentrations of 0.5, 0.3, 0.5 and 10 wt%, respectively. Polyurethane microfiber membranes were prepared by electrostatic air-jet spinning.

[0099] (2) The ultrafine fiber membrane obtained by spinning is transported to the rigid hot rolling roll assembly 21 for hot rolling for 2 seconds. The hot rolling temperature is set to 200℃ and the hot rolling pressure is 2MPa to obtain an ultrafine fiber membrane with tiny physical bonding points.

[0100] (3) Subsequently, the ultrafine fiber membrane with tiny physical bonding points was transported to the ultraviolet cluster assembly 22 for chemical cross-linking. The ultraviolet wavelength was set to 365nm and the irradiation intensity was 500mW, which realized the high-strength welding of the ultrafine fiber membrane at the micro-nano scale and obtained an ultrafine fiber membrane with enhanced mechanical properties.

[0101] The prepared polyurethane microfiber membrane material has a tensile strength of 20 MPa, a porosity of 89.3%, and an elastic recovery rate of 91.6%.

[0102] Example 5:

[0103] Using the apparatus provided in Example 1, this embodiment provides a method for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber membrane materials, comprising the following steps:

[0104] (1) Polyolefin elastomer, 184 initiator and 1,4-butanediol dimethacrylate monomer were added to polyacrylonitrile organic polymer spinning solution (solvent was N,N-dimethylacetamide) and mixed evenly to prepare spinning solutions with elastomer, initiator, reactive monomer and polymer concentrations of 4, 1, 5 and 25 wt%, respectively; polyacrylonitrile ultrafine fiber membrane was prepared by electrostatic air-jet spinning.

[0105] (2) The ultrafine fiber membrane obtained by spinning is transported to the rigid hot rolling roll assembly 21 for hot rolling for 10 seconds. The hot rolling temperature is set to 350℃ and the hot rolling pressure is 8MPa to obtain an ultrafine fiber membrane with tiny physical bonding points.

[0106] (3) Subsequently, the ultrafine fiber membrane with tiny physical bonding points was transported to the ultraviolet cluster assembly 22 for chemical cross-linking. The ultraviolet wavelength was set to 405nm and the irradiation intensity was 3000mW, which realized the high-strength welding of the ultrafine fiber membrane at the micro-nano scale and obtained an ultrafine fiber membrane with enhanced mechanical properties.

[0107] The prepared polyacrylonitrile microfiber membrane material has a tensile strength of 15 MPa, a porosity of 85.2%, and an elastic recovery rate of 90%.

[0108] Example 6:

[0109] Using the apparatus provided in Examples 1 and 2, this embodiment provides a method for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber membrane materials, comprising the following steps:

[0110] (1) Polyether ester elastomer, TMO initiator and hexanediol dimethacrylate monomer were added to polyvinylidene fluoride organic polymer spinning solution (solvent is N,N-dimethylformamide) and mixed evenly to prepare spinning solutions with elastomer, initiator, reactive monomer and polymer concentrations of 8, 1, 2 and 35 wt%, respectively; ultrafine fiber membranes were prepared by electrostatic air-jet spinning.

[0111] (2) The ultrafine fiber membrane obtained by spinning is transported to the rigid hot rolling roll assembly 21 for hot rolling for 5 seconds. The hot rolling temperature is set to 220℃ and the hot rolling pressure is 6MPa to obtain an ultrafine fiber membrane with tiny physical bonding points.

[0112] (3) Subsequently, the ultrafine fiber membrane with tiny physical bonding points was transported to the ultraviolet cluster assembly 22 for chemical cross-linking. The ultraviolet wavelength was set to 395nm and the irradiation intensity was 1500mW, which realized the high-strength welding of the ultrafine fiber membrane at the micro-nano scale and obtained an ultrafine fiber membrane with enhanced mechanical properties.

[0113] The prepared polyvinylidene fluoride ultrafine fiber membrane material has a tensile strength of 12 MPa, a porosity of 88.2%, and an elastic recovery rate of 94.3%.

[0114] Example 7:

[0115] Using the apparatus provided in Example 3, this example provides a method for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber flocculent materials. The specific steps are as follows:

[0116] (1) Polystyrene and N,N-dimethylformamide were prepared into a 10wt% spinning solution, and polystyrene microfiber flocculent material was prepared by electrostatic air-jet spinning. This material was then transported into the sol-coated assembly 3. At this point, acrylic sol particles with a diameter of 1μm and a solid content of 40wt% were uniformly dispersed within the semi-enclosed shell 314; at 0.5m... 3 At a suction rate of / h, the sol particles diffuse evenly into the interior of the ultrafine fiber flocs, and move to the overlap point to form a coating point under the action of the capillary formed by the fiber overlap.

[0117] (2) The fiber flocs are then transferred to the microwave heating assembly 4. The microwave frequency is set to 3000MHz and the heating temperature is 60℃. The sol coating points are rapidly dehydrated and solidified under the high-frequency vibration of the microwave, forming a stable and strong welding point at the overlap point, thus obtaining an ultrafine fiber floc with enhanced mechanical properties.

[0118] The prepared polystyrene microfiber flocculent material has a thickness of 3 cm, a tensile strength of 0.73 MPa, a compression resilience of 95%, and a bulk density of 2.5 mg / cm³. 3 .

[0119] Example 8:

[0120] Using the apparatus provided in Example 3, this example provides a method for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber flocculent materials. The specific steps are as follows:

[0121] (1) Polyacrylonitrile and dimethyl sulfoxide were prepared into a 12 wt% spinning solution, and polyacrylonitrile microfiber flocculent material was prepared by electrostatic air-jet spinning. The material was then transported into the sol-coated assembly 3. At this time, styrene sol particles with a diameter of 7 μm and a solid content of 25 wt% were uniformly dispersed in the semi-enclosed shell 314. 3 At a suction rate of / h, the sol particles diffuse evenly into the interior of the ultrafine fiber flocs, and move to the overlap point to form a coating point under the action of the capillary formed by the fiber overlap.

[0122] (2) The fiber flocs are then transferred to the microwave heating assembly 4. The microwave frequency is set to 200000MHz and the heating temperature is 80℃. The sol coating points quickly lose water and solidify under the high-frequency vibration of the microwave, forming a stable and strong welding point at the overlap point, thus obtaining an ultrafine fiber floc with enhanced mechanical properties.

[0123] The prepared polyimide microfiber wadding material has a thickness of 4 cm, a tensile strength of 0.68 MPa, a compression resilience of 93%, and a bulk density of 5 mg / cm³. 3 .

[0124] Example 9:

[0125] Using the apparatus provided in Example 3, this example provides a method for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber flocculent materials. The specific steps are as follows:

[0126] (1) A spinning solution of tetraethyl orthosilicate and acetic acid was prepared into a 40 wt% spinning solution, and 1 wt% polyvinyl alcohol was added as an auxiliary raw material. Silica ultrafine fiber flocculent material was prepared by electrostatic air-jet spinning and transported to the sol-coated assembly 3. At this time, silica sol particles with a diameter of 3 μm and a solid content of 50 wt% were uniformly dispersed within the semi-enclosed shell 314. 3 At a suction rate of / h, the sol particles diffuse evenly into the interior of the ultrafine fiber flocs, and move to the overlap point to form a coating point under the action of the capillary formed by the fiber overlap.

[0127] (2) The fiber flocs are then transferred to the microwave heating assembly 4. The microwave frequency is set to 300000MHz and the heating temperature is 700℃. The sol coating points quickly lose water and solidify under the high-frequency vibration of the microwave, forming a stable and strong welding point at the overlap point, thus obtaining an ultrafine fiber floc with enhanced mechanical properties.

[0128] The prepared silica ultrafine fiber flocculent material has a thickness of 5 cm, a tensile strength of 0.37 MPa, a compression resilience of 92%, and a bulk density of 3.7 mg / cm³. 3 .

[0129] Example 10:

[0130] Using the apparatus provided in Example 3, this example provides a method for mechanical reinforcement of micro-nano-scale welding of ultrafine fiber flocculent materials. The specific steps are as follows:

[0131] (1) Tetraethyl orthosilicate, aluminum isopropoxide, aluminum nitrate, and ethanol were mixed to form a 53 wt% spinning solution. Mullite microfiber flocculent material prepared by an electrostatic air-jet spinneret was transported into the sol-coated assembly 3. At this point, silica sol particles with a diameter of 2 μm and a solid content of 60 wt% were uniformly dispersed within the semi-enclosed shell 314; at 1.5 m... 3At a suction rate of / h, the sol particles diffuse evenly into the interior of the ultrafine fiber flocs, and move to the overlap point to form a coating point under the action of the capillary formed by the fiber overlap.

[0132] (2) The fiber flocs are then transferred to a microwave-assisted heating tunnel furnace. The microwave frequency is set to 300000MHz and the heating temperature is set to 800℃. The sol coating points are rapidly dehydrated and solidified under the high-frequency vibration of the microwave, forming stable and strong welding points at the overlap points, thus obtaining ultrafine fiber flocs with enhanced mechanical properties.

[0133] The prepared mullite ultrafine fiber flocculant material has a thickness of 3 cm, a tensile strength of 0.42 MPa, a compression resilience of 90%, and a bulk density of 4.3 mg / cm³. 3 .

[0134] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for mechanical reinforcement through micro-nano-scale welding of ultrafine fiber materials, characterized in that, Submicron-scale directional welding is performed between ultrafine fibers to obtain ultrafine fiber materials with submicron-scale bonding points. By utilizing the interaction of the submicron-scale bonding points, ultrafine fiber materials with enhanced mechanical properties are obtained. The microfiber material includes a microfiber membrane or microfiber flakes. When the microfiber material is a microfiber membrane, the mechanical reinforcement method of the microfiber membrane includes the following steps: S1-1. The ultrafine fiber membrane material is subjected to a micro-point hot rolling reaction to form an ultrafine fiber membrane with micron-level fusion bonding points; the raw materials used in the ultrafine fiber membrane material include a low-melting-point elastic oligomer, a photoreactive agent, and a spinning solution; the photoreactive agent includes a photoinitiator and a photocrosslinking agent; the final concentration of the photoinitiator in the raw materials is 0.3~3wt%, and the final concentration of the photocrosslinking agent in the raw materials is 0.5~5wt%. The micro-point hot rolling reaction method is as follows: using small-sized rigid rolling points with a diameter of 1~30 μm, hot rolling temperature of 100~350℃, loading pressure of 2~8 MPa, and hot pressing time of 2~10 s; S1-2. The ultrafine fiber membrane with micron-level fusion bonding points obtained in step S1-1 is subjected to ultraviolet irradiation, which causes nanoscale cross-linking to form between fiber intersections, forming a welding structure at the micro-nano hierarchical scale, and obtaining an ultrafine fiber membrane with enhanced mechanical properties; the ultraviolet wavelength during ultraviolet irradiation is 365~405 nm. When the microfiber material is a microfiber filament, the mechanical reinforcement method of the microfiber filament includes the following steps: S2-1. Under the traction of negative pressure and electrostatic force, micron-sized sol particles are attached to the ultrafine fiber material, and under capillary action, the micron-sized sol particles are directionally transferred to the fiber overlap to form ultrafine fiber flocs with sol coating points; the micron-sized sol particles are selected from any one of styrene, acrylic acid, vinyl acetate-acrylic acid, styrene-vinyl acetate, vinyl acetate-tert-carbonic acid-acrylic acid, natural rubber, environmentally friendly resin, silica sol, aluminum sol, zirconium sol, titanium sol, silica-alumina sol, or silica-zirconium sol, with a solid content of 20~60wt%, and the diameter of the micron-sized sol particles is 1~10 μm; S2-2. The ultrafine fiber flocs obtained in step S2-1, which have sol-coated points at the fiber overlaps, are heated to form a micro-nano scale welded structure, resulting in ultrafine fiber flocs with enhanced mechanical properties.

2. The mechanical reinforcement method for micro-nano-scale welding of ultrafine fiber materials according to claim 1, characterized in that, In step S1-1, the ultrafine fiber membrane material is an ultrafine organic polymer fiber membrane material, which is selected from any one or more of the following ultrafine organic polymer fiber membrane materials: polyurethane, polyethylene oxide, polyamide, polyvinyl chloride, polyvinylidene fluoride, polycarbonate, aramid 1313, polymethyl methacrylate, polyimide, polystyrene, polybenzimidazole, polyethylene terephthalate, polycaprolactone, polylactic acid, polyhydroxybutyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polysulfone, polyethyleneimine, polyimide, polypropylene glycol terephthalate, or polyvinyl butyral fiber. The low-melting-point elastic oligomer is selected from any one or more of thermoplastic polyurethane elastomers, polyolefin elastomers, dynamically vulcanized polyolefin elastomers, polystyrene elastomers, polyether ester elastomers, or polyamide elastomers, and the final concentration of the low-melting-point elastic oligomer in the raw material is 0.5~8 wt%. The photoinitiator is selected from any one or more of TPO, TPO-L, 907 initiator, ITX, 184 initiator, 1173 initiator, BDK, OMBB, BP, CBP, PBZ, 369 initiator, 819 initiator, 754 initiator, 127 initiator, 784 initiator or TMO; The photocrosslinking agent is selected from any one or more of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylolpropane trimethacrylate, N,N-methyleneacrylamide, or epichlorohydrin.

3. The mechanical reinforcement method for micro-nano-scale welding of ultrafine fiber materials according to claim 1, characterized in that, In step S2-1, the ultrafine fiber floc material is an ultrafine organic polymer fiber floc material or an ultrafine inorganic fiber floc material, wherein: The ultrafine organic polymer fiber flocs are selected from any one or more of the following ultrafine organic polymer fiber flocs: polyurethane, polyethylene oxide, polyamide, polyvinyl chloride, polyvinylidene fluoride, polycarbonate, aramid 1313, polymethyl methacrylate, polyimide, polystyrene, polybenzimidazole, polyethylene terephthalate, polycaprolactone, polylactic acid, polyhydroxybutyrate, polyacrylonitrile, polyvinyl alcohol, polyethylene, polysulfone, polyethyleneimine, polyimide, polypropylene glycol terephthalate, or polyvinyl butyral fiber. The ultrafine inorganic fiber flocs are selected from any one or more of the following: silicon dioxide, aluminum oxide, zirconium oxide, titanium dioxide, and mullite fibers.

4. The mechanical reinforcement method for micro-nano-scale welding of ultrafine fiber materials according to claim 1, characterized in that, In step S2-2, the heating method is microwave-assisted heating, with a heating temperature of 20~800℃ and a frequency of 3000~300000 MHz.

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