Nanofiber non-woven material as well as preparation method and application thereof

Abstract

The invention discloses a nanofiber non-woven material and a preparation method and application thereof, and belongs to the technical field of nanofiber non-woven materials. The preparation method of the nanofiber non-woven material comprises the following steps: mixing and melting a polymer A and a polymer B to obtain a first melt; mixing and melting the polymer B and the polymer C to obtain a second melt; performing conjugate spinning on the first melt and the second melt, then sequentially performing cooling, drafting, net forming and consolidation, and finally performing reduction splitting by adopting a reduction splitting agent to obtain the nanofiber non-woven material, wherein the viscosity of the polymer B is lower than that of the polymer A and the polymer C; the polymer B is removed through a reduction splitting agent; the polymer A and the polymer C are both polymers resistant to decrement splitting agents. According to the method, through the online synergistic effect of shear field reconstruction, conjugate spinning and blended spinning, the scale of the nanofibers can be controlled and adjusted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven materials, in particular to a nanofiber non-woven material and a preparation method and application thereof. BACKGROUND

[0002] In the field of non-woven materials, nanofibers are widely used in filtration, biomedical, energy storage and other fields due to their high specific surface area, excellent filtration performance and flexibility. In recent years, the technology for preparing nanofiber non-woven materials has gradually attracted attention. The reconstruction of the melt shear field and the one-step method aim to directly prepare new nanofiber non-woven materials with narrow diameter distribution or different morphologies through a simplified process, thereby reducing production costs and improving the performance of non-woven materials. However, existing one-step method technologies still face many challenges, such as difficulty in controlling fiber morphology and limitations in material functionality. Therefore, developing an efficient and controllable one-step method for preparing nanofiber non-woven materials has become a technical problem to be solved in this field. SUMMARY

[0003] The purpose of the present application is to provide a nanofiber non-woven material and a preparation method and application thereof to solve the problems existing in the prior art.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions: One of the technical solutions of the present application: a preparation method of a nanofiber non-woven material, comprising the following steps: mixing and melting polymer A and polymer B to obtain a first melt; mixing and melting polymer B and polymer C to obtain a second melt; co-spinning the first melt and the second melt, then sequentially performing cooling, drawing, webbing and consolidation, and finally using a mass reduction opening agent for mass reduction opening to obtain the nanofiber non-woven material; the viscosity of polymer B is lower than that of polymer A and polymer C; polymer B is removed by a mass reduction opening agent; polymer A and polymer C are both mass reduction opening agent-resistant polymers.

[0005] Preferably, in the first melt, the mass percentage of polymer B and polymer A is (10-90%):(90-10%); In the second melt, the mass percentage of polymer B and polymer C is (10-90%):(90-10%).

[0006] Preferably, the mass percentage of the first melt and the second melt is (10-90%):(90-10%).

[0007] Preferably, the polymer A comprises one of polyethylene terephthalate and modified polymers thereof, polytrimethylene terephthalate and modified polymers thereof, polyamide and modified polymers thereof, polypropylene and modified polymers thereof, polybutylene terephthalate and modified polymers thereof. The polymer B comprises one of polyethylene and modified polymers thereof, alkali-soluble polyester and modified polymers thereof, thermoplastic polyvinyl alcohol and modified polymers thereof, polystyrene and modified polymers thereof, cellulose acetate propionate and modified polymers thereof, cellulose acetate butyrate and modified polymers thereof. The polymer C comprises one of polyethylene terephthalate and modified polymers thereof, polytrimethylene terephthalate and modified polymers thereof, polyamide and modified polymers thereof, polyphenylene sulfide and modified polymers thereof, polystyrene and modified polymers thereof.

[0008] Preferably, the spinning assembly used in the conjugate spinning is one of an orange petal type spinning assembly, a fixed island type spinning assembly, a sheath-core type spinning assembly and a side-by-side type spinning assembly.

[0009] Preferably, the number of orange petals of the orange petal type spinning assembly is 4-128 petals. The number of fixed islands of the fixed island type spinning assembly is 16-1000 islands.

[0010] Preferably, the weight-reducing opening agent comprises water, an organic solvent, an alkaline aqueous solution or an acidic aqueous solution.

[0011] More preferably, the weight-reducing opening agent comprises water, toluene, benzene or an aqueous NaOH solution.

[0012] Preferably, the viscosity difference between the polymer A and the polymer B is 1-1000 Pa·s. The viscosity difference between the polymer C and the polymer B is 1-1000 Pa·s. The consolidation mode comprises needle punching, water jetting, thermal bonding or ultrasonic bonding.

[0013] The present application adopts a two-component spunbonding device, controls the viscosity difference between the polymer B and the polymer A and the polymer C and the complex ratio by reconfiguring the shear field of the polymer melt through melt blending technology, so as to obtain a new type of indefinite island-sea fiber with uniform diameter distribution or different morphologies, and a new type of nanofiber nonwoven material is obtained through drawing, webbing, consolidation and weight-reducing opening.

[0014] The diameter of the fiber before the weight-reducing opening is 10-50 μm, the polymer B in the fiber is not resistant to the weight-reducing opening agent, the polymer A and the polymer C are high polymers that can be melt-spun and resistant to the weight-reducing opening agent, so that the polymer A and the polymer C are retained and the polymer B is removed completely during the weight-reducing opening process, thereby forming a multi-scale nanofiber nonwoven material with alternating thick and thin and different lengths, and in the prepared nonwoven material, the diameter of one component is 50-800 nm, and the diameter of another component is 100-1000 nm.

[0015] The second technical solution of the present application is a nanofiber nonwoven material prepared by the preparation method.

[0016] The third technical solution of the present application is an application of the nanofiber nonwoven material in the preparation of synthetic leather, gas-liquid filtration, energy storage or medical material.

[0017] The present application discloses the following technical effects: (1) The present application realizes the synchronous forming (single-step forming) of nanofiber double-component fibers through the online synergistic effect of conjugate spinning (mixing of the first melt and the second melt) and blending spinning (melt spinning of the polymer A and the polymer B, and melt spinning of the polymer B and the polymer C), and solves the problems of long process, insufficient interface stability, uneven fiber mixing and easy delamination existing in the conventional offline composite process.

[0018] (2) The nanofiber nonwoven material of the present application has the advantages of softness, air permeability and moisture permeability.

[0019] (3) The method of the present application can prepare a nonwoven material with uniform distribution of nanofibers (the diameter of a single nanofiber is 50-800 nm), which significantly improves the problem of uneven distribution of conventional indefinite island fiber after opening. The method of the present application can also prepare a multi-scale nanofiber nonwoven material with different scale nanofibers coexisting (the diameter of a single component is 50-800 nm, and the diameter of another single component is 100-1000 nm), which can be used for developing synthetic leather, filter material, wiping material, protective products, bedding, face mask and the like. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 The preparation flowchart of the nanofiber nonwoven material of the embodiment is shown in the figure. Figure 2 A schematic diagram of the spinning device used for the examples, wherein 1 is a first feeding hopper, 2 is a first screw extruder, 3 is a first metering pump, 4 is a composite spinning assembly, 5 is a blowing device, 6 is a draw frame, 7 is a webbing curtain, 8 is a negative pressure suction device, 9 is a water jet fixing device, 10 is a weight reduction device, 11 is a washing device, 12 is a drying device, 13 is a winding device, 14 is a second feeding hopper, 15 is a second screw extruder, 16 is a second metering pump; Figure 3 A cross-sectional SEM image of the nascent fiber prepared in step (4) of Example 1; Figure 4 A schematic diagram of the cross-sectional structure of the nascent fiber prepared in step (4) of Example 1; Figure 5 An SEM image of the multi-scale nanofiber nonwoven material prepared in step (5) of Example 1; Figure 6 A fiber diameter distribution graph of the multi-scale nanofiber nonwoven material prepared in step (5) of Example 1; Figure 7 A schematic diagram of the cross-sectional structure of the nascent fiber prepared in step (4) of Example 4; Figure 8 A schematic diagram of the cross-sectional structure of the composite fiber prepared in step (4) of Comparative Example 1. DETAILED DESCRIPTION

[0022] Various illustrative embodiments of the present application are now described in detail below. The description made herein is not to be construed as limiting the present application, but rather merely as describing certain aspects, features, and embodiments of the present application.

[0023] It should be understood that the terms used herein are merely descriptive, but that the application should not be construed as being limited thereto. In addition, for numerical ranges recited in the application, it is contemplated that every number between the upper and lower limits of the range is specifically recited. Every smaller range that falls between the recited ranges, as well as every individual number within the recited ranges, is also contemplated. The upper and lower limits of these smaller ranges and individual numbers can independently be included or excluded in the ranges.

[0024] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In the case of conflict between the present specification and any document incorporated by reference, the present specification will control.

[0025] Many modifications and variations of the present application described in the specification are possible without departing from the scope or spirit of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.

[0026] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having" or the like are open-ended expressions that are intended to denote the presence of stated features, items, elements, components, or the like but do not preclude the presence or addition of one or more other features, items, elements, components, or the like.

[0027] It should be noted that the present application does not describe in detail the conventional means of the art, and is not the focus of the present application.

[0028] In the first aspect of the present application, a preparation method of nanofiber nonwoven material is provided, comprising the following steps: (1) mixing and melting polymer B with polymer A to obtain a first melt; (2) mixing and melting polymer B with polymer C to obtain a second melt; (3) using a double-screw composite spinning device, the first melt and the second melt are converged at the spinneret through a spinning assembly (orange petal type spinning assembly, fixed island type spinning assembly, skin-core type spinning assembly or side-by-side type spinning assembly), and are extruded into a filament bundle together, and then are sequentially cooled, drawn and webbed to obtain a matrix-fibril type composite filament fiber web; (4) after the matrix-fibril type composite filament fiber web is consolidated, a mass reduction fibrillation agent is used for mass reduction fibrillation, and then washing and winding are performed to obtain a nanofiber nonwoven material; Among them, the viscosity of polymer B is lower than that of polymer A and polymer C. By controlling the viscosity and the composite ratio, polymer B can be in the "sea" phase, and polymer A and polymer C can be in the "island" phase, so as to obtain an indefinite island-sea fiber.

[0029] The mass reduction fibrillation is to remove polymer B by using a mass reduction fibrillation agent; polymer A and polymer C are both mass reduction fibrillation agent-resistant polymers. The mass reduction fibrillation agent can completely dissolve polymer B, leaving nanofibers of polymer A and polymer C.

[0030] Preferably, in the first melt, the mass percentage of polymer B and polymer A is (10-90%): (90-10%); In the second melt, the mass percentage of polymer B and polymer C is (10-90%): (90-10%); The mass percentage of the first melt and the second melt is (10-90%): (90-10%).

[0031] Preferably, polymer A includes one of polyethylene terephthalate (PET) and its modified polymers, polyethylene terephthalate and its modified polymers, polyamide and its modified polymers, polypropylene (PP) and its modified polymers, and polybutylene terephthalate (PBT) and its modified polymers; more preferably, it is one of polyethylene terephthalate and its modified polymers, and polyamide and its modified polymers. Polymer B includes one of polyethylene and its modified polymers, alkali-soluble polyester and its modified polymers, thermoplastic polyvinyl alcohol and its modified polymers, polystyrene (PS) and its modified polymers, cellulose acetate propionate (CAP) and its modified polymers, and cellulose acetate butyrate and its modified polymers, more preferably one of polyethylene and its modified polymers and alkali-soluble polyester and its modified polymers; Polymer C includes one of polyethylene terephthalate (PET) and its modified polymers, polyethylene terephthalate and its modified polymers, polyamide and its modified polymers, polyphenylene sulfide and its modified polymers, and polystyrene (PS) and its modified polymers, more preferably one of polyethylene terephthalate and its modified polymers, polyethylene terephthalate and its modified polymers, and polyamide and its modified polymers.

[0032] Preferably, the number of segments in the orange-petal type spinning assembly is 4-128, more preferably 16 or 32; the number of islands in the island-fixed type spinning assembly is 16-1000, more preferably 16-37.

[0033] Preferably, the fiber-reducing agent includes water, organic solvent, alkaline aqueous solution, or acidic aqueous solution.

[0034] Preferably, the fiber-reducing agent includes water, toluene, benzene, or an aqueous solution of NaOH, more preferably water or toluene.

[0035] Preferably, the fiber opening time is 10-90 min, more preferably 60-90 min; the fiber opening temperature is 40-100℃, more preferably 80-100℃.

[0036] Preferably, the viscosity difference between polymer A and polymer B is 1-1000 Pa·s; The viscosity difference between polymer C and polymer B is 1-1000 Pa·s.

[0037] Preferably, cooling is achieved by using cooling air, which is side-blowing with a wind speed of 0.5-3.0 m / s, a temperature of 15-30℃, and a humidity of 40-80%.

[0038] Preferably, the first melt and the second melt pass through the metering pump, and converge at the spinneret (the number of holes of the spinneret is 1000-2000 holes / m) to form the composite fiber, and after the completion of the compounding, the fiber is drawn; the drawing equipment is preferably a tubular drawing, and the speed of the drawing is 2000-6000 m / s; the drawing is carried out under the cooling wind.

[0039] Preferably, the drawing is an air flow drawing, and after the air flow drawing, the polymer can be directly formed into a web to obtain a matrix-fibril type composite filament fiber web.

[0040] Preferably, the basis weight of the matrix-fibril type composite filament fiber web is 60-1000 g / m 2 .

[0041] Preferably, the consolidation method includes needle punching, water jetting, thermal bonding or ultrasonic bonding, and is preferably needle punching or water jetting.

[0042] Preferably, the washing agent used for washing is water, and the washing temperature is 80-100℃, and more preferably 90-100℃, so as to remove the residual weight-reducing fibrillating agent.

[0043] The present application adopts three kinds of polymer raw materials, adjusts the compounding ratio, the viscosity difference between polymer A and polymer B, and the viscosity difference between polymer B and polymer C, and through the steps of melt spinning, web forming, consolidation and weight-reducing fibrillation, a new type of non-woven material containing one or two different diameter distribution fibers (a new type of non-woven material containing one fiber with a diameter of 50-800 nm; a new type of non-woven material containing two fibers with different diameters, and the diameters of the fibers are 50-800 nm and 100-1000 nm) is prepared, the preparation process of the nanofiber non-woven material is simplified, and the softness, moisture permeability and air permeability of the non-woven material are improved.

[0044] In the second aspect of the present application, a nanofiber non-woven material prepared by the above preparation method is provided.

[0045] In the third aspect of the present application, the nanofiber non-woven material is applied in the preparation of synthetic leather, gas-liquid filtration, energy storage or medical material preparation.

[0046] In the specific embodiments of the present application, there is no special requirement for the melting temperature, which is set according to the types of the selected polymer A, polymer B and polymer C.

[0047] In the specific embodiments of the present application, the polymer A, polymer B and polymer C are selectively subjected to drying treatment; the drying treatment method is dry tower drying, and 0.3 m 3 / h of air with a dew point of-60℃ is introduced into the bottom of the dry tower for protection, so that the water content of the polymer A, polymer B and polymer C is controlled to be below 100 ppm.

[0048] Example 1 A method for preparing a multi-scale nanofiber nonwoven material: (1) Dry polyamide 6 (PA6, weight average molecular weight of 20000 g / mol) by dry tower drying, and introduce 0.3 m 3 / h of air with a dew point of -60℃ at the bottom of the dry tower to protect the polyamide 6 (PA6) so that the water content of the polyamide 6 (PA6) is controlled to be below 100 ppm, to obtain dry polyamide 6 (PA6).

[0049] (2) Add polyethylene (PE, no need to dry, weight average molecular weight of 60000 g / mol; viscosity of 40 Pa·s at a temperature of 270℃ and a shear rate of 3000 s -1 ) and polyamide 6 (viscosity of 65 Pa·s at a temperature of 270℃ and a shear rate of 3000 s -1 ) in a mass ratio of 6:4 into the first feeding hopper 1, melt through the first screw extruder 2 to form a first melt.

[0050] (3) Add polyethylene (PE, viscosity of 40 Pa·s) and polyamide 6 (PA6, viscosity of 65 Pa·s) in a mass ratio of 4:6 into the second feeding hopper 14, melt through the second screw extruder 15 to form a second melt.

[0051] (4) Control the mass of the first melt and the second melt by the first metering pump 3 and the second metering pump 16, so that the first melt and the first melt are combined at the spinneret plate (the number of holes of the spinneret plate is 1200 holes / m) of the composite spinning assembly 4 (island-in-the-sea type spinning assembly, 19 islands) in a mass ratio of 5:5, and the filaments are extruded together to obtain a nascent filament, which is cooled by the blowing device 5, stretched by the stretcher 6, and then falls onto the webbing curtain 7, and is webbed under the action of the negative pressure suction device 8 to obtain a matrix-fibril type composite filament fiber web with a grammage of 400 g / m 2 .

[0052] The blowing device 5 is used to generate cooling air (i.e. to generate a cooling blowing effect), and the cooling air is side blowing air with a speed of 1.2 m / s, a temperature of 16℃, and a humidity of 65%.

[0053] The stretching is tubular stretching, and the speed of the stretching is 4500 m / s; the stretching is performed under the cooling air.

[0054] (5) After the matrix-fibril type composite filament fiber web is hydroentangled and fixed by the hydroentangling and fixing device 9, it enters the mass reduction device 10, and is toluene mass reduction and fibrillation (dissolution of low-density polyethylene), and finally is washed by the washing device 11, dried by the drying device 12, and wound by the winding device 13 in sequence to obtain a matrix-fibril type composite filament fiber web with a grammage of 200 g / m2 Multi-scale nanofiber nonwoven material.

[0055] The detergent used in the washing is water, and the temperature of the washing is 100°C.

[0056] The time for the reduction opening is 90 min, and the temperature is 90°C.

[0057] The diameters of one group of fibers in the multi-scale nanofiber nonwoven material prepared in this example are 210-420 nm, and the diameters of another group of fibers are 600-1000 nm.

[0058] The preparation flowchart of the multi-scale nanofiber nonwoven material is shown in Figure 1 , and the schematic diagram of the spinning device used is shown in Figure 2 .

[0059] The cross-sectional SEM image of the primary filaments prepared in step (4) of this example is shown in Figure 3 , and the schematic diagram of the cross-sectional structure is shown in Figure 4 .

[0060] The SEM image of the multi-scale nanofiber nonwoven material prepared in this example is shown in Figure 5 , and the fiber diameter distribution diagram is shown in Figure 6 .

[0061] Example 2 The same as example 1, except that the mass ratio of polyethylene (PE) and polyamide 6 (PA6) in step (2) is 6:4. The mass ratio of polyethylene (PE) and polyamide 6 (PA6) in step (3) is 6:4.

[0062] The basis weight of the matrix-fibril type composite filament fiber web prepared in step (4) is 500 g / m 2 .

[0063] The material prepared by the method of this example has a fiber diameter distribution concentrated in 210-420 nm, and has good softness, compared with example 1.

[0064] Example 3 The same as example 1, except that the viscosity of polyethylene (PE) in step (2) is 27.68 Pa·s; and the viscosity of polyamide 6 (PA6) is 54.95 Pa·s.

[0065] The viscosity of polyethylene (PE) in step (3) is 27.68 Pa·s; and the viscosity of polyamide 6 (PA6) is 54.95 Pa·s.

[0066] The fiber of the material prepared by the method of the embodiment is finer, and can be better applied in the field of filtration, and has better softness and filtration effect than the material prepared in embodiment 1.

[0067] Embodiment 4 The same as embodiment 1, except that the mass ratio of polyethylene (viscosity of 27.68 Pa·s) and polyamide 6 (viscosity of 70.36 Pa·s) in step (2) is 5:5.

[0068] The mass ratio of polyethylene (viscosity of 27.68 Pa·s) and polyamide 6 (viscosity of 70.36 Pa·s) in step (3) is 5:5.

[0069] The mass ratio of the first melt and the first melt in step (4) is 5:5.

[0070] The composite spinning assembly 4 used in step (4) is an orange petal type composite spinning assembly, 8+8 petals, and the number of holes of the spinneret is 1200 holes / m.

[0071] The cross-sectional structure diagram of the primary filament prepared in step (4) of the embodiment is shown in Figure 7 .

[0072] Embodiment 5 The same as embodiment 1, except that the polyamide 6 in step (2) is replaced by PET (weight average molecular weight of 23328 g / mol; viscosity of 53.65 Pa·s at a temperature of 285℃ and a shear rate of 3000 s -1 ).

[0073] The nanoscale fiber diameter distribution obtained in the embodiment is 100-300 nm and 600-1000 nm.

[0074] Comparative example 1 Preparation method of micrometer fiber non-woven material: (1) Dry polyethylene terephthalate (PET, weight average molecular weight of 23328 g / mol) and polyamide 6 (PA6, weight average molecular weight of 57682 g / mol) respectively, the drying method is drying tower drying, 0.3 m 3 / h of air with a dew point of -60℃ is introduced into the bottom of the drying tower for protection, so that the water content of polyethylene terephthalate (PET) and polyamide 6 (PA6) is controlled below 100 ppm, and dry polyethylene terephthalate (PET) and polyamide 6 (PA6) are obtained.

[0075] (2) Dry polyethylene terephthalate (PET; viscosity of 53.65 Pa·s at a temperature of 285℃ and a shear rate of 3000 s -1The polyamide 6 (PA6; viscosity at 270℃ and shear rate of 3000s -1 The viscosity at 270℃ and shear rate of 3000s

[0076] The viscosity at 270℃ and shear rate of 3000s 2 .

[0077] (4) The mass of the first melt and the second melt was controlled by the first metering pump 3 and the second metering pump 16, and the first melt and the second melt entered the spinning beam in a mass ratio of 5:5, and then the two melts were distributed by the spinning assembly 4 (the spinning assembly was hollow orange petal shape), to form composite fibers at the spinneret (the number of holes of the spinneret was 1200 holes / meter). After cooling by the blowing equipment 5, the composite fibers were drawn by the draw frame 6, and then fell onto the webbing curtain 7, and were webbed under the action of the negative pressure suction equipment 8, to obtain the matrix-fibril type composite filament fiber web, and the basis weight was 200g / m 2 .

[0078] (5) After the matrix-fibril type composite filament fiber web was hydroentangled and fixed by the hydroentangling and fixing equipment 9 (the fiber was opened at the same time of hydroentangling and fixing), the composite filament fiber web directly entered the drying equipment, to obtain the micron fiber nonwoven material with a basis weight of 200g / m 2 .

[0079] The cross-sectional structure diagram of the composite fiber prepared in step (4) of the present comparative example is shown in Figure 8 .

[0080] The properties of the nonwoven material prepared in the examples and the comparative examples are shown in Table 1 and Table 2.

[0081] Table 1 Performance Comparison Table 2 Performance Comparison The above examples only describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for preparing a nanofiber nonwoven material, characterized in that, Includes the following steps: Polymer A and polymer B are mixed and melted to obtain the first melt; Polymer B and polymer C are mixed and melted to obtain a second melt; The first melt and the second melt are conjugate spun and then cooled, drawn, web-formed and consolidated in sequence. Finally, a fiber-reducing agent is used to reduce fiber opening to obtain the nanofiber nonwoven material. The viscosity of polymer B is lower than that of polymers A and C; Polymer B is removed by a fiber-reducing agent; both polymer A and polymer C are polymers resistant to fiber-reducing agents.

2. The preparation method according to claim 1, characterized in that, In the first melt, the mass percentages of polymer B and polymer A are (10-90%) : (90-10%). And / or, in the second melt, the mass percentage of polymer B and polymer C is (10-90%): (90-10%).

3. The preparation method according to claim 1, characterized in that, The mass percentage of the first melt and the second melt is (10-90%): (90-10%).

4. The preparation method according to claim 1, characterized in that, The polymer A includes one of polyethylene terephthalate and its modified polymers, polyethylene terephthalate and its modified polymers, polyamide and its modified polymers, polypropylene and its modified polymers, and polyethylene terephthalate and its modified polymers. And / or, the polymer B includes one of polyethylene and its modified polymers, alkali-soluble polyester and its modified polymers, thermoplastic polyvinyl alcohol and its modified polymers, polystyrene and its modified polymers, cellulose acetate propionate and its modified polymers, and cellulose acetate butyrate and its modified polymers. And / or, the polymer C includes one of polyethylene terephthalate and its modified polymers, polyethylene terephthalate and its modified polymers, polyamide and its modified polymers, polyphenylene sulfide and its modified polymers, and polystyrene and its modified polymers.

5. The preparation method according to claim 1, characterized in that, The spinning assembly used in the conjugate spinning is one of the following: orange petal type spinning assembly, island type spinning assembly, core-sheath type spinning assembly, and parallel type spinning assembly.

6. The preparation method according to claim 5, characterized in that, The number of orange petals in the orange petal-shaped spinning assembly is 4-128. And / or, the number of islands in the island-type spinning assembly is 16-1000 islands.

7. The preparation method according to claim 1, characterized in that, The fiber-reducing agent includes water, organic solvents, alkaline aqueous solutions, or acidic aqueous solutions.

8. The preparation method according to claim 1, characterized in that, The viscosity difference between polymer A and polymer B is 1-1000 Pa·s; And / or, the viscosity difference between polymer C and polymer B is 1-1000 Pa·s; And / or, the consolidation method includes needle punching, hydroentangling, thermal bonding, or ultrasonic bonding.

9. A nanofiber nonwoven material prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the nanofiber nonwoven material of claim 9 in the preparation of synthetic leather, gas-liquid filtration, energy storage or medical materials.

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